Post on 04-Aug-2020
Research ArticleAntimicrobial Applications of Transition Metal Complexes ofBenzothiazole Based Terpolymer Synthesis Characterizationand Effect on Bacterial and Fungal Strains
Mohamed A Riswan Ahamed1 Raja S Azarudeen2 and N Mujafar Kani3
1 Department of Chemistry Oxford Engineering College Tiruchirappalli Tamil Nadu 620 009 India2Department of Chemistry Coimbatore Institute of Technology Coimbatore Tamil Nadu 641 014 India3 PG and Research Department of Chemistry Jamal Mohamed College (Autonomous) Tiruchirappalli Tamil Nadu 620 020 India
Correspondence should be addressed to Mohamed A Riswan Ahamed polyrizwangmailcom
Received 29 May 2014 Accepted 20 August 2014 Published 14 September 2014
Academic Editor Claudio Pettinari
Copyright copy 2014 Mohamed A Riswan Ahamed et al This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited
Terpolymer of 2-amino-6-nitro-benzothiazole-ethylenediamine-formaldehyde (BEF) has been synthesized and characterized byelemental analysis and various spectral techniques like FTIR UV-Visible and 1H and 13C-NMRThe terpolymer metal complexeswere prepared with Cu2+ Ni2+ and Zn2+ metal ions using BEF terpolymer as a ligand The complexes have been characterized byelemental analysis and IR UV-Visible ESR 1H-NMR and 13C-NMR spectral studies Gel permeation chromatography was usedto determine the molecular weight of the ligandThe surface features and crystalline behavior of the ligand and its complexes wereanalyzed by scanning electron microscope and X-ray diffraction methods Thermogravimetric analysis was used to analyze thethermal stability of the ligand and its metal complexes Kinetic parameters such as activation energy (119864
119886) and order of reaction
(119899) and thermodynamic parameters namely Δ119878 Δ119865 119878lowast and 119885 were calculated using Freeman-Carroll (FC) Sharp-Wentworth(SW) and Phadnis-Deshpande (PD) methods Thermal degradation model of the terpolymer and its metal complexes was alsoproposed using PDmethod Biological activities of the ligand and its complexes were tested against Shigella sonnei Escherichia coliKlebsiella species Staphylococcus aureus Bacillus subtilis and Salmonella typhimurium bacteria and Aspergillus flavus Aspergillusniger Penicillium species Candida albicans Cryptococcus neoformansMucor species fungi
This paper is dedicated to the memory of Dr A Burkanudeen who had a road accident and sadly died on December 28 2012In the grace of almighty May his soul rest in peace
1 Introduction
The construction of polymers with d-block transition metalcomplexes has been developed rapidly in recent years owingto their interesting high thermal stability and enormouspharmacological activity along with potential applications asfunctional materials Owing to the high thermal stability ofthe polymers they have adverse applications such as in wastewater treatment for metal recovery protective coatings ther-mally stable materials water disinfectants antifouling paintsantimicrobial and surgical materials gels and ointments formedical uses and biological activity [1 2]
Based on the survey made in the literature it hasbeen found that good work has been reported on poly-merscopolymersterpolymers acting as various types ofligands with transition metal ions [3ndash5] The chemicalproperties of benzothiazole based compounds have beenintensively investigated in several research fields especiallyin polymer field because of their high thermal stability andpharmacological activity [6 7]The thiazole ring dramaticallyincreases the diversity of certain biological properties suchas antibacterial [8] antiviral [9] and antitubercular [10]activities These activities are probably due to the presence ofthe ndashN=CndashS group present in the thiazole moiety [11]
Hindawi Publishing CorporationBioinorganic Chemistry and ApplicationsVolume 2014 Article ID 764085 16 pageshttpdxdoiorg1011552014764085
2 Bioinorganic Chemistry and Applications
A series of 4-isopropylthiazole-2-carbohydrazide ana-logs derived from clubbed oxadiazole-thiazole and triazole-thiazole derivatives have been synthesized and characterizedby Mallikarjuna et al [12] The synthesized compoundswere evaluated for their preliminary in vitro antibacterialantifungal and antitubercular activity againstMycobacteriumtuberculosis H
37Rv strain by broth dilution assay method
Ahamad et al [13] reported a new class of metal chelatedpolyurea for its excellent antimicrobial activity against Saureus E coli B subtilis and S typhi The Cu2+ chelatedpolyurea shows higher zone of inhibition than the otherones due to higher stability constant and may be used inbiomedical applications Patel et al [14] reported that thesynthesis of low molecular weight polymeric resins containsseveral functional groups in gaining importance to involvethe antimicrobial activity All the synthesized polymers wereexamined for the antimicrobial activity against bacteria(Escherichia coli Bacillus subtilis and Staphylococcus citreus)fungi (Aspergillus niger Sporotrichum pulverulentum andTrichoderma lignorum) and yeast (Candida utilis Saccha-romyces cerevisiae and Pichia stipitis) It was observed thatmost of the polymers could be used as antibacterial andantifungal agents Alagawadi and Alegaon [15] synthesizedseries of novel 5-substituted-24-thiazolidinedione deriva-tives and studied the antimicrobial screening tests whichreveal the new compounds that act as antibacterial andantifungal agents Ashok et al [16] accounted for the onepot synthesis of some novel derivatives of thiazolo[23-b]dihydropyrimidinone possessing 4-methylthiophenylmoi-ety and evaluation of their antibacterial and antifungalactivities They have exhibited moderate to excellent growthinhibition against the chosen bacteria and fungi due to thepresence of N and S donor atoms present in the antimicrobialagents Ahamad et al [17] studied the in vitro antibacte-rial and antifungal assay of poly-(ethylene oxamide-NN1015840-diacetate) and its polymer-metal complexes The polymer-metal complexes showed excellent antibacterial activitiesagainst both types of microorganisms the polymeric ligandwas also found to be effective but less so than the polymer-metal complexes On the basis of the antimicrobial behaviorthese polymers may be used as antifungal and antifoulingcoating materials in fields like life-saving medical devicesand the bottoms of ships Recently our research groupsynthesized new types of polymer and oligomer ligands andtheir transition metal complexes for their excellent thermalstability and antimicrobial activity [18ndash20]
The present paper aims to introduce the new 2-amino-6-nitro-benzothiazole-ethylenediamine-formaldehyde (BEF)terpolymer ligand and its complexes It provides thesynthesis characterization thermal properties and bio-logical activities of the 2-amino-6-nitro-benzothiazole-ethylenediamine-formaldehyde (BEF) terpolymer ligandand its complexes The physicochemical properties andcharacterization of the BEF terpolymer ligand and itscomplexes were carried out by elemental analysis molarconductivity magnetic susceptibilities GPC FTIR UV-Visible ESR 1H and 13C NMR SEM XRD and TGA Fromthe TGA data the various kinetic and thermodynamic
parameters were evaluated for the BEF terpolymer ligandand its complexes The decomposition model for thethermal degradation reaction was also proposed Theantimicrobial activities of the terpolymer ligand and itscomplexes were reported against six bacterial strains suchas Shigella sonnei Escherichia coli Klebsiella species (NCIM2719) Staphylococcus aureus (ATCC 25923) Bacillus subtilis(ATCC 6633) and Salmonella typhimurium (ATCC 23564)and six fungal strains such as Aspergillus flavus Aspergillusniger Penicillium species Candida albicans Cryptococcusneoformans andMucor species
2 Experimental
21 Materials 2-Amino-6-nitro-benzothiazole and ethyl-enediamine were procured from Sigma Aldrich USA andused as received Formaldehyde (37) was procured fromMerck India and used as receivedDouble distilledwaterwasused for all the experiments All other chemicals and metalsalts were of analytical grade and were used without furtherpurification
22 Synthesis of Terpolymer Ligand Acollectivemixture of 2-amino-6-nitro-benzothiazole (976 g 005M) and ethylene-diamine (812mL 005M) with formaldehyde (811mL01M) was taken as monomers in a clean round bottom flaskequipped with a mechanical stirrer and a refluxed condenserusing dimethyl formamide (DMF) as a reaction medium in1 1 2 mole ratio The homogeneous mixture was refluxed inan oil bath at 150 plusmn 2∘C with constant stirring for 6 h Afterthe reaction time was over the resultant mixture was cooledand then poured into crushed ice with vigorous shaking Theobtained precipitate was separated out by filtration washedwith hot water ether and methanol to remove the unreactedmonomers and recrystallized from tetrahydrofuran (THF)The route of synthesis for the BEF terpolymer is shown inScheme 1
23 Preparation of Metal Complexes The terpolymer metalcomplexes have been prepared using the synthesized terpoly-mers as ligand with few transition metal ions such as Cu2+Ni2+ and Zn2+ ionsThe BEF terpolymer (2 g) was taken in around bottom flask and immersed for 2 h in ethanol solutionfor swelling The cupric nitrate (1 g) was dissolved in ethanolsolution and then poured into round bottom flask equippedwith mechanical stirrer and a reflux condenser The reactionmixture was refluxed at 60∘C for 3 h The obtained colloidalprecipitate in the flask was separated out The product wasthen filtered off andwashed with ether and ethanol to removethe impuritiesThis process has been repeated several times toseparate the purified product The resultant purified samplewas air dried powdered and kept in vacuum desiccatorwith silica gel The same procedure was also followed for thepreparation of BEF complexes with Ni2+ and Zn2+ metal ionsin the form of their nitrate salts The scheme of preparationof the BEF complex with Cu2+ Ni2+ and Zn2+ metal ions isshown in Scheme 2
Bioinorganic Chemistry and Applications 3
O2N
O2N
N
2-Amino-6-nitro-benzothiazole
2-Amino-6-nitro-benzothiazole-Ethylenediamine-Formaldehyde terpolymer
[BEF terpolymer]
Ethylenediamine
DMFFormaldehyde
N
S
Sn
n
nNH2
NH NH NH
CH2
CH2 CH2 CH2 CH2
H HC
O
CH2NH2 NH2 2n+ +
150 plusmn 2∘C6h
Scheme 1 Reaction route of the BEF terpolymer ligand
60∘C
O2NBEF terpolymer ligand
BEF terpolymer metal complexes
EtOH
N
Sn
NH NH NHCH2 CH2 CH2 CH2
O2N
N
Sn
NH NH
M2
NHCH2 CH2 CH2 CH2
3 h reflux
M2+
[M = Cu(II) Ni(II) and Zn(II)]
Scheme 2 Reaction route of the BEF metal complexes
24 Elemental Analysis The elemental analysis has beencarried out using Elementar instrument model Vario ELIII Germany The percentage of elements such as carbon(C) hydrogen (H) nitrogen (N) and sulphur (S) presentin the 2-amino-6-nitro-benzothiazole-ethylenediamine-formaldehyde (BEF) terpolymer and its metal complexeswith the metal ion content was determined
25 Gel Permeation Chromatography The number average(119872119899) weight average (119872
119908) and size average (119872
119911)molecular
weights of terpolymer were measured by gel permeationchromatography (Shimadzu Japan) using tetrahydrofuran(THF) as a mobile phase and CLC polystyrene as a stationaryphase in the column
26 Spectral Analyses TheUV-Visible spectra of the terpoly-mers and its metal complexes were recorded in Shimadzu(model 1601PC) UV-Visible spectrophotometer Japan The
ESR spectra of the terpolymer and its metal complexeswere recorded in Bruker instrument model EleXsys E 500USA The FTIR spectra of the terpolymer and its metalcomplexeswere obtainedwithAvatar (model 330USA) FTIRspectrometer using KBr The 1H and 13C NMR spectra wererecorded on a Bruker 400MHz (USA) NMR spectrometerusing DMSO-d
6as a solvent
27 SEM and XRD Methods The surface analysis of theBEF terpolymer and its metal complexes was examined atdifferent magnifications by scanning electron microscopeusing Hitachi instrument model S-3000H Japan The XRDanalysis of the terpolymer and its metal complexes wasperformed using PANalytical instrument (XrsquoPert PRO TheNetherlands)
28 Thermogravimetric Analysis The thermal stability of theBEF terpolymer and its metal complexes was observed bythermogravimetric analysis using TA instruments model
4 Bioinorganic Chemistry and Applications
SDT Q600 USA at a heating rate of 20∘Cmin in a staticnitrogen atmosphere
281 Thermal Degradation Kinetics and Mechanism Sharp-Wentworth and Freeman-Carroll methods have beenemployed for the determination of kinetic and thermo-dynamic parameters such as order of reaction (119899) activationenergy (119864
119886) entropy change (Δ119878) free energy change
(Δ119865) apparent entropy (119878lowast) and frequency factor (119885)Phadnis-Deshpande method has also been used to proposethe thermal degradation mechanism for the synthesizedterpolymer and its metal complexes [20]
29 Antimicrobial Analysis by Disc Diffusion Method TheBEF terpolymer and its metal complexes were screened fortheir antimicrobial activity by disc diffusion method [21]against six bacterial strains such as Shigella sonneiEscherichiacoli Klebsiella species (NCIM 2719) Staphylococcus aureus(ATCC 25923) Bacillus subtilis (ATCC 6633) and Salmonellatyphimurium (ATCC 23564) and six fungal strains such asAspergillus flavus Aspergillus niger Penicillium species Can-dida albicans Cryptococcus neoformans and Mucor speciesAntimicrobial activity was tested by the filter paper discdiffusion technique involving the cultures of the selectedorganisms for 24 hMuellerHinton agar number 2 (HiMediaIndia) was used as the bacteriological medium and sterileyeast nitrogen base with 2 agar (Hi Media India) was usedas the fungal medium The test solutions of the terpolymerand its metal complexes were prepared in sterile dimethylsulfoxide (DMSO) solvent for the study The synthesized ter-polymer and its metal complexes were tested at different con-centrations ranging from 50 to 1000 ppm to find out the min-imum concentration of the terpolymer ligand and its metalcomplexes required for inhibiting the growth of microbes
Amoxicillin (100 120583gmL) was taken as the standard forantibacterial activity The organism was seeded into sterilenutrient agar medium by mixing one mL of inoculum with20mL sterile melted nutrient agar kept at 48ndash50∘C in a sterilepetri dish The medium was allowed to solidify first Thenthe test solutions the standard drugs and the blank wereimpregnated in whatman filter paper discs placed on thesolidified medium in the petri dish and left undisturbed for2 h at room temperatureThepetri disheswere then incubatedat 37∘C for 24 h and the zone of inhibition for the test samplesstandard and control (DMSO) was measured
Sterile yeast nitrogen base (Hi Media) with 2 agar wasinoculated by a rotating swab (soaked in standard inoculumsuspension) over the surface of the media Fluconazole(100mcgmL) was taken as the standard for antifungalactivity The test solution impregnated discs were placed onthe agar andwere incubated at 37∘C for 18 hThe zone of inhi-bition was measured by measuring the minimum dimensionof the zone of fungal growth around the filter paper disc
3 Results and Discussion
31 Physicochemical and Analytical Data The physicochem-ical and analytical data of the BEF terpolymer and its metal
complexes are given in Table 1 The BEF terpolymer is yellowin colour and itsmetal complexes are brown forCu2+ complexand yellow for Ni2+ and Zn2+ complexesThe yield of the BEFterpolymer ligand was 79 and the yield of Cu2+ Ni2+ andZn2+ complexes was 80 77 and 78 respectively Basedon the analytical data from the elemental analysis the empir-ical formula of the BEF terpolymer ligand and its metal com-plexes is found to be in good agreement with the calculatedelemental values of C H N S and M The amount of metalions present in the metal complexes indicates 1 2ML sto-ichiometry suggesting six coordination involving two coor-dinated water molecules for BEFndashCu BEFndashNi and BEFndashZncomplexes From the results the general empirical formulaof the repeating unit of the BEF terpolymer is C
11H13N5O2S
and of the metal complexes is C22H26N10O4S2Cusdot2H
2O
for BEFndashCu C22H26N10O4S2Nisdot2H
2O for BEFndashNi and
C22H26N10O4S2Znsdot2H
2O for BEFndashZn From the molar con-
ductance values the metal complexes were found to beelectrolytes
32 Molecular Weight Measurements The average molecularweight of the BEF terpolymer was determined by gel perme-ation chromatographyTheweight average (119872
119908) and number
average (119872119899)molecular weight of the terpolymer were found
to be 1941 and 1940 respectively The polydispersity index(119872119908119872119899) was found to be 10005 The average molecular
weight (119872119911) of the terpolymer was found to be 1942 The
polydispersity index (119872119911119872119908) of the terpolymer is 10005
The polydispersity index (119872119908119872119899) and (119872
119911119872119908) values for
the terpolymer indicate the narrow distribution of molecularweight in the terpolymer
33 FTIR Spectra The FTIR spectra of BEF terpolymerligand and its metal complexes are depicted in Figure 1 andthe data are presented in Table 2 The band frequencies andthe groups assigned to both terpolymer ligand and its metalcomplexes are based on the earlier literature [22 23] Theligand spectrum showed a band appearing in the range of3455ndash3297 cmminus1 is assigned to the ndashNH asymmetric andsymmetric vibrations The 268-trisubstituted benzothiazolering is confirmed by sharp and medium absorption bandsappearing between 1296 and 825 cmminus1 A strong band thatappeared at 1532 cmminus1 is due to the ndashNH bending vibrationA band that appeared at 2731 cmminus1 is assigned to the ndashCHstretching vibrations present in the aromatic ring The bandsappearing in the region of 3078ndash2936 cmminus1 are attributed tondashCH2asymmetric and symmetric vibrations present in the
terpolymer ligand The presence of ndashCH2bending vibration
in NndashCH2ndashCH2ndashN bridge in the spectrum is confirmed by
the absorption band that appeared at 1450 cmminus1In the spectra of BEF metal complexes the bands are
slightly broadened compared to the terpolymer ligand Theband that appeared at 1532 cmminus1 is assigned to ndashNH bendingvibrations in the ligand spectrum that is shifted to the lowerfrequencies (1521 to 1527 cmminus1) in the case of polymer-metalcomplexes This shift is due to the coordination of metalions through the lone pair of both nitrogen atoms present
Bioinorganic Chemistry and Applications 5
Table 1 Physicochemical and analytical data
Compound Empirical formula ofthe repeating unit Formula mass
Elemental analysis ()Λ (Ωminus1 cm2 molminus1)Found (calc)
C H N S MBEF ligand C11H13N5O2S 27936 4709 (4729) 416 (435) 2521 (2549) 1120 (1139) mdash mdashBEFndashCu C22H26N10O4S2Cusdot2H2O 65823 4071 (4092) 439 (462) 2174 (2194) 919 (927) 931 (962) 13205BEFndashNi C22H26N10O4S2Nisdot2H2O 65334 4025 (4037) 447 (479) 2129 (2146) 962 (983) 926 (945) 9837BEFndashZn C22H26N10O4S2Znsdot2H2O 66010 4023 (4052) 423 (445) 2138 (2153) 912 (929) 941 (970) 11329C carbon H hydrogen N nitrogen S sulphur and M metal ion
Table 2 FTIR data
Compound Observed frequencies (cmminus1)BEF ligand BEFndashCu BEFndashNi BEFndashZn
] NH (asym and sym) 3455minus3297 3408ndash3296 3348ndash3295 3345ndash3280] NH (bending) 1532 1527 1526 1521CH (stretching) 2731 2697 2712 2725] CH2 (asym and sym) 3078ndash2936 3093ndash2912 3098ndash2932 3087ndash2945] CH2 (bending in NndashCH2ndashCH2ndashN) 1450 1448 1449 1446268-tri substitution (benzothiazole) 1296minus825 1298ndash825 1293ndash827 1292ndash825] NrarrM mdash 432 433 433] CndashNO2 1505ndash1518 1503ndash1576 1524ndash1575 1513ndash1583] C=N 1540 1590 1586 1580] CndashSndashC 740 753 763 748
Tran
smitt
ance
()
(a)
4000 3500 3000 2500 2000 1500 1000 500
(b)
(c)
(d)
Wavenumber (cmminus1)
Figure 1 FTIR spectra of (a) BEF (b) BEFndashCu (c) BEFndashNi and (d)BEFndashZn
in the ethylenediamine moiety It is a clear evidence for theinvolvement of nitrogen atoms in the chelationThis is furthersupported by the appearance of ]NrarrM stretching vibrationat 432ndash433 cmminus1
34 Electronic and ESR Spectra and Magnetic MomentsThe electronic spectra of the BEF terpolymer and its metalcomplexes are shown in Figure 2 and the data are presentedin Table 3 The spectrum of the ligand showed two bands at
100
Abso
rban
ce
050
0400
Wavelength (nm)600200 800
(d)(c)(b)
(a) (d)((c)(b)((((
(a)aaaaa
Figure 2 Electronic spectra of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
260 and 370 nmThese observed positions for the absorptionbands have different intensitiesThe less intense band 260 nmis due to (120587 rarr 120587
lowast) allowed transition of chromophoregroups like NO
2 gtC=N and C=C which are in conjugation
with an aromatic nucleus (benzothiazole ring) and the moreintense band 370 nm may be due to (119899 rarr 120587
lowast) transition ofndashNH groupsThus 120587 rarr 120587lowast transition indicates the presence
6 Bioinorganic Chemistry and Applications
Table 3 UV-Visible ESR data and magnetic moments
Compound Transitions (cmminus1) Assignments Geometry ESR Magnetic moment (BM)119892II 119892
perp
BEF 260 nm 120587 rarr 120587lowast mdash mdash mdash mdash370 nm 119899 rarr 120587
lowast
BEFndashCu14295 1
119861119892rarr
2119864119892
Octahedral 221 211 18516465 1119861119892rarr
2119864119892
24580 Charge transfer
BEFndashNi12474 3119879
2119892(119865) larr 3119860
2119892(119865)
Octahedral mdash mdash 30514642 31198791119892(119865) larr 3119860
2119892(119865)
24370 31198791119892(119875) larr 3119860
2119892(119865)
BEFndashZn mdash mdash Octahedral mdash mdash Diamagnetic
0 1000
Inte
nsity
2000 3000 4000 5000 6000 7000G
Figure 3 ESR spectra of BEFndashCu complex
of aromatic nucleus and 119899 rarr 120587lowast transition indicates thepresence of ndashNH groups The electronic spectrum of BEFndashCu metal complex exhibited bands at 14295 16465 and24580 cmminus1 and the assignments are 1119861
119892rarr2119864119892 1119861119892
rarr2119864119892 and charge transfer spectra which lead to a distorted
octahedral geometry with the magnetic moment of 185 BMThe electronic spectrum of BEFndashNi exhibits three bands at12474 14642 and 24370 cmminus1 assigned to the spin allowedtransitions 3119879
2119892(119865) larr 3119860
2119892(119865) 3119879
1119892(119865) larr 3119860
2119892(119865) and
31198791119892(119875) larr 3
1198602119892(119865) in an octahedral environment with a
magnetic moment of 305 BMThe diamagnetic nature of theBEFndashZn is also confirmed with octahedral geometry Basedon the literature the geometry is assigned to all the metalcomplexes [24]
The ESR spectrum of BEFndashCu complex is shown inFigure 3 and its spectral data are presented in Table 3 Thespectrum provides useful information about the metal ionenvironment in the respective complexes The ESR spectrumof BEFndashCu metal complex showed that 119892
= 221 and
119892perp= 211 lead to an octahedral environment According to
Kivelson and Neimen [25] the bond between the ligand andthe metal possesses a more covalent character than ionic In
general both the parallel and the perpendicular 119892 values canbe used to calculate the 119866 value by the following equation
119866 =119892minus 2002
119892perpminus 2002
(1)
Using the above equation the 119866 value for BEFndashCu was192 which clearly indicates that the complex forms with astrong field ligand
35 Nuclear Magnetic Resonance The NMR (1H and 13C)spectra for BEF terpolymer ligand and its zinc metal complex(due to d9 and d8 configurations both NMR spectra forcopper and nickel metal complexes are complicated) wererecorded to elucidate the structure of the ligand and itscomplex
351 1H NMR Spectra The 1H NMR spectra of BEF ter-polymer ligand and its Zn2+ metal complex are shownin Figure 4 The signals obtained for the terpolymer andits metal complexes were interpreted on the basis of thedata available in the literature [22 26] The spectrum ofterpolymer showed that the signals appearing in the region of739ndash824 ppm are assigned to all the protons of the aromaticring A peak appearing at 250 is assigned to the methyleneprotons of the terpolymer ligand The terpolymer spectrumshowed a signal appearing at 472 ppm that is assigned tothe ndashNH protons of ethylenediamine moiety and the peakappearing at 865 ppm is assigned to ndashNH proton of thiazolering A weak signal appearing at 302 ppmmay be assigned toethylenic protons of an ArndashCH
2ndashNHndashCH
2moiety
The spectrum of the Zn2+ complex showed multiplet inthe range of 740ndash824 ppm is assigned to the aromatic protonsand the methylene protons appeared at 215ndash250 ppm Thesignal obtained at 508 ppm is assigned to ndashNH protons ofethylenediamine and this shift from its ligand gives a clearevidence for the complexation of the ligand with the metalions through the lone pair of nitrogen of ethylenediaminemoiety
352 13C NMR Spectra The 13C NMR spectra of the BEFterpolymer ligand and its Zn2+ metal complex are shown in
Bioinorganic Chemistry and Applications 7
(ppm)
12345678910
(a)
(ppm)1 0234567891011
(b)
Figure 4 1H-NMR spectra of (a) BEF ligand and (b) BEFndashZn
200 180 160 140 120 100 80 60 40 20 0(ppm)
(a)
200 180 160 140 120 100 80 60 40 20 0(ppm)
(b)
Figure 5 13C-NMR spectra of (a) BEF ligand and (b) BEFndashZn
O2N S
N
NH NH
M
NHCH2 CH2 CH2 CH2
n
O2NS
NNH NH NHCH2 CH2 CH2 CH2
n
H2OH2O
[M = Cu(II) Ni(II) and Zn(II)]
Figure 6 Proposed geometry of BEF metal complexes
Figure 5 The observed chemical shifts are assigned on thebasis of the literature [22 27]The spectrum of ligand showedthat the corresponding peaks at 1717 1585 1315 1219 14061167 and 1253 ppm are attributed to the aromatic carbonsof the benzothiazole ring The peak appearing at 502 ppmis assigned to the methylenic carbon of NHndashCH
2bridge in
the ligand The spectrum of Zn2+ complex showed the peaksfor aromatic ring in the same region which was appearingin its parent ligand The shifting of the methylene carbonfrom 502 to 561 ppm from its ligand clearly suggests that the
coordination takes place between the nitrogen atoms of theethylenediamine moiety
From the elemental and spectral data (FTIR UV-VisESR and NMR (1H and 13C)) the structure of the BEF ter-polymer ligand and its metal complexes has been confirmedThe proposed geometry of the BEF complexes is shown inFigure 6
36 Surface Analysis The SEM is applied to understandthe surface features of the polymeric materials The SEM
8 Bioinorganic Chemistry and Applications
(a) (b)
(c) (d)
(e)
Figure 7 SEM images of (a) and (b) BEF ligand (c) BEFndashCu (d) BEFndashNi and (e) BEFndashZn
photographs in times1000 and times2000 magnifications for BEFligand and times3000 magnifications for BEF complexes areshown in Figure 7 The white bar at the bottom of the SEMphotographs represents the scale The SEM photographs ofthe BEF terpolymer ligand show leaf like appearance Thescattered structure of the terpolymer establishes a transitionstate between the crystalline and the amorphous phases [28]
Themorphology of BEF terpolymer resin exhibits growthof crystals from polymer solutions corresponding to the
most prominent organization in polymers on a large scalewith spherulites Ideally spherulites are the aggregates ofsubmicroscopic size particles Spherulites are characterizedby secondary structural features such as faint corrugationsThe SEM photographs of polymers have an appreciableamorphous fraction with a small amount of shallow pitsThe surface of BEF metal complexes contributes to greatersegments of crystalline regions compared to their parentligand which may arise from the contraction of the voids by
Bioinorganic Chemistry and Applications 9
Inte
nsity
(au
)
0 20 40 60 802120579
(a)
Inte
nsity
(au
)
0 20 40 60 802120579
(b)
Inte
nsity
(au
)
0 20 40 60 802120579
(c)
Inte
nsity
(au
)
0 20 40 60 802120579
(d)
Figure 8 XRD patterns of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
the cooperative contribution of the ligand for complexationwith metal ions or the disappearance of the voids in therearrangement of polymer chains for complexation withmetal ions This is a further evidence for the complexationof BEF terpolymer with metal ions
37 XRD Studies X-ray diffraction (XRD) patterns of BEFand its metal complexes are shown in Figure 8 It provides adetailed comparative account of the behavior of the terpoly-mer and itsmetal complexesThepattern of BEF ligand showsthe main characteristic peak and broad shoulder In view ofthe relative half value width it may be concluded that thepolymer is partially crystalline and the broad characteristicpeak indicates the amorphous nature of the terpolymerTherefore the BEF terpolymer has transition state betweenamorphous state and crystalline state whereas its metalchelates possess crystalline nature The enhanced crystallinebehavior of the BEF complexes may be due to the insertion ofmetal ions with their parent ligand [29]
38 Thermal Stability Thermal stability of the BEF terpoly-mer and its metal complexes was analyzed by thermogravi-metric analysis (TGA) The thermograms of the terpolymer
and its metal complexes are shown in Figure 9 and their per-centages of weight loss at various temperatures are presentedin Table 4
381Thermal Stability of BEF Terpolymer From the thermo-gram of BEF terpolymer there were three stages of degra-dation (200ndash320∘C 320ndash580∘C and 580ndash835∘C) observedThe first stage of degradation was observed between 200∘Cand 320∘C (found 5883 calc 5794) which reveals thedegradation of the benzothiazole ring The second stageof degradation begins at 320∘C and ends at 580∘C (found1003 calc 0931) which may be due to the eliminationof cross-linkages The third and final stage of degradation isobserved above 580∘C and continued up to 825∘C (found2506 calc 2473) which can be attributed to the weightloss of aliphatic group (ethylenediamine moiety) from theBEF terpolymer
382 Thermal Stability of BEF Metal Complexes In generalthe water of hydration may be considered as either crystalwater molecules or coordination water molecules Accordingto Nikolaev et al [30] water eliminated below 150∘C can beconsidered as crystal or lattice water and water eliminated
10 Bioinorganic Chemistry and Applications
Table 4 TGA data for thermal stability
Compound Percentage of weight loss at various temperatures11987950
lowast (∘C) 119879maxlowastlowast (∘C)
100 200 300 400 500 600 700 800 (∘C)BEF ligand 0153 0365 4414 6236 6718 7140 8224 9442 310 825BEFminusCu 0194 1432 3180 4301 4996 5549 6686 8122 500 860BEFminusNi 0893 1660 3735 4935 6460 8767 mdash mdash 405 650BEFminusZn 1464 2262 3833 4616 5726 6492 7614 9129 425 830lowastTemperature of 50 weight loss lowastlowastmaximum decomposition temperature
80
60
40
20
0
0
(a)(b)
(c)(d)
200 400 600 800 1000
100
Wei
ght (
)
Temperature (∘C)
Figure 9 TGA of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d)BEFndashZn
above 150∘C may be due to its coordination to the metalatom present in chelates In the present study in the case ofBEFndashCu2+ Ni2+ and Zn2+ complexes the removal of waterfrom the complex was completed within 150∘C These watermolecules are probably crystal or lattice water moleculesTheremoval of water molecules observed in the range of 150ndash200∘C (found 559ndash608 calc 545ndash551) of all the metalchelates is due to the elimination of two coordinated watermolecules These observations further confirm the distortedoctahedral geometry of BEF metal complexes
The thermogravimetric curves of all the BEF metalchelates showed two degradation steps after loss of watermolecules whichmay indicate that the first step (200ndash600∘C)is faster than the second step (600ndash860∘C) This may bedue to the fact that the noncoordinated part of the liganddecomposes firstwhile the coordinated part decomposes laterand finally it may form the representative metal oxides Theweight of the residues confirms fairly well that ofmetal oxides(found 1247ndash1362 calc 1143ndash1232)
The thermal degradation data of the BEF terpolymerand its metal complexes reveal that the polymeric complexesshow better stability than the BEF terpolymer due to thecoordination of metal ions The order of thermal stability ofthe BEF polymer and its complexes is BEFndashCu2+ gt BEFndashZn2+ gt BEF ligand gt BEFndashNi2+ The greater stability of themetal complexes may be due to the coordination and theenhanced cross linking nature with crowd effect of the metal
complexes [31] In the case of Ni2+ complex the degradationoccurred exceptionally at low temperature compared to theirligand which may be due to the oxidation of polymer by thecatalytic action of the metal ion [32]
383 Thermal Kinetics
(1) Sharp-Wentworth and Freeman-Carroll Method Ther-mal kinetic analysis was performed using Sharp-Wentworthmethod and Freeman-Carroll methods The activationenergy (119864
119886) and order of reaction (119899) plots for BEF terpoly-
mer ligand and its metal complexes by Sharp-Wentworthand Freeman-Carroll methods are shown in Figures 10 11and 12 The expressions used to calculate the kinetic andthermodynamic parameters are presented as follows
(i) Entropy change (Δ119878)
Intercept = log 119870119877
ℎΦ119864119886
+Δ119878
2303119877 (2)
where 119870 = 13806 times 10minus16 ergdegmole 119877 =
1987 caldegmole (8314 JKMol) ℎ = 6625 times
10minus27 erg sec Φ = 0166 Δ119878 = change in entropyand 119864
119886= activation energy from graph
(ii) Free energy change (Δ119865)
Δ119865 = Δ119867 minus 119879Δ119878 (3)
where Δ119867 = enthalpy change = activation energy 119879 =temperature in119870 and Δ119878 = result from (2)
(iii) Frequency factor (119885)
11986123
=log119885119864
119886
119877Φ (4)
11986123
= log 3 + log [1 minus 3radic1 minus 120572] minus log119901 (119909) (5)
where 119885 is the frequency factor 119861 is calculatedfrom (5) log119901(119909) is calculated from Doylersquos tablecorresponding to activation energy and 120572 is degreeof transformation (120572 = 119908119882
119888)
(iv) Apparent entropy (119878lowast)
119878lowast= 2303 log 119885ℎ
119877119879lowast (6)
where119885 is calculated from (4) and 119879lowast is half decom-position temperature
Bioinorganic Chemistry and Applications 11
1000T (Kminus1)
Intercept = minus535
minus45
minus50
minus55
minus60
minus65
minus70
minus75
minus80
10 15 20 25 30
Ea = 952
log[
(dC
dT
)(1
minusC
)]
(a)
minus64
minus62
minus60
minus58
minus56
minus54
minus52
1000T (Kminus1)10 15 20 25 30
Intercept = minus527
Ea = 1297
log[
(dC
dT
)(1
minusC
)]
(b)
minus64
minus62
minus50
minus52
minus54
minus56
minus58
minus60
1000T (Kminus1)10 15 20 25 30
Intercept = minus513
Ea = 693
log[
(dC
dT
)(1
minusC
)]
(c)
minus50
minus51
minus52
minus53
minus54
minus55
minus56
minus57
minus58
minus59
1000T (Kminus1)10 15 20 25 30
Intercept = minus538
Ea = 1108
log[
(dC
dT
)(1
minusC
)]
(d)
Figure 10 Sharp-Wentworth plots of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Table 5 Kinetic and thermodynamic parameters data
CompoundActivation energy
(119864119886kJmolminus1) Entropy change
(Δ119878J)Free energy
change (Δ119865kJ)Frequency
factor (119885sminus1)Apparent
entropy (119878lowastJ)Order of
reaction (119899)lowastSW lowastlowastFC
BEF ligand 952 1039 minus15811 5940 1310 minus2295 090BEFminusCu 1297 1367 minus15425 9079 1205 minus2331 104BEFminusNi 693 460 minus16290 7057 1537 minus2294 093BEFminusZn 1108 1213 minus16001 8013 1243 minus2318 102lowastSW Sharp-Wentworth lowastlowastFC Freeman-Carroll
Further from the knowledge of activation energy cal-culated by Freeman-Carroll method it is possible to eval-uate the values of various thermodynamic parameters Theorder of reaction (119899) and activation energy (119864
119886) and the
thermodynamic parameters such as frequency factor (119885)entropy change (Δ119878) free energy change (Δ119865) and apparententropy (119878lowast) are presented inTable 5The119864
119886values calculated
by SW and FC methods are in good agreement with eachother The order of activation energies for BEF ligand andits Cu2+ Ni2+ and Zn2+ complexes is parallel to the orderof their thermal stability [32] The values of thermodynamic
parameters were comparable indicating a common modeof decomposition reaction The abnormal low values offrequency factor (119885) indicate that the decomposition reactionof BEF terpolymer and its metal complexes can be depictedas a slow reaction The order of reactions (119899) of BEF ligandand its metal complexes is found to be 090 104 093 and102 respectively Hence the BEF terpolymer and its mealcomplexes may be following nearly a first order kinetics
(2) Phadnis-Deshpande Method The activation energiescalculated for BEF ligand and its metal complexes using
12 Bioinorganic Chemistry and Applications
minus00012minus00010minus00008minus00006minus00004minus00002minus00000
26242220181614121008060402
log(dWdt)
(1T)
n = 090
logW
r
logWr
(a)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
20
19
18
17
16
15
14
13
12
11
10
log(dWdt)
(1T)
n = 104
logWr
logW
r
(b)
15
16
17
18
19
14
13
12
11
10
09
log(dWdt)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
(1T)
n = 093logW
r
logWr
(c)
15
16
17
18
14
13
12
11
10
log(dWdt)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
(1T)
n = 102
logW
r
logWr
(d)
Figure 11 Freeman-Carroll plots (119899) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Phadnis-Deshpande method are presented in Table 6 Fromthe 119864
119886values it is possible to propose the degradation
reactionmechanism using PDmethod Further the 119864119886values
calculated by PD method are in good agreement with FCand SW methods Based on the closest 119864
119886values calculated
by PD SW and FC methods the Power law mechanismsuits very well for the BEF ligand and BEFndashCu and BEFndashZn metal complexes However BEFndashNi complex follows theBrounshtein-Ginstling 3-dimensional diffusion mechanism
39 Biological Studies
391 Antibacterial Activity To determine the antibacterialactivity of the BEF terpolymer and its Cu2+ Ni2+ andZn2+ complexes the disc diffusion method was used withamoxicillin as the standard antibiotic The prepared com-pounds were tested against Shigella sonnei Escherichia coliKlebsiella species Staphylococcus aureus Bacillus subtilis andSalmonella typhimuriummicroorganisms
Table 7 contains the screening results corresponding tothe polymeric ligand and its metal complexes with fairinhibition of growth against the tested organisms Shigella
sonnei is a nonmotile non-spore-forming and facultativeanaerobic gram-negative bacterium Shigella bacteria multi-ply within colonic epithelial cells and cause mucosal ulcer-ation inflammation bleeding high fever malaise diarrheaand tenesmus The ligand and its metal complexes showeda reasonable activity against the S sonnei species E coliis an aerobic gram-negative and rod shaped bacteriumInfection of E coli can lead to bloody diarrhea and kidneyfailureThe polymeric ligand and its complexes hold amodestactivity against the E coli Klebsiella is a genus of nonmotileand gram-negative bacteria that infects sites such as nasalpassages liver lung urinary tract bloodstream eye boneand joints It causes a wide range of disease states notablypneumonia septicemia soft tissue infections biliary tractinfection infection of the upper and lower respiratory tractand liver abscess The BEF ligand and its metal complexesshowed a reasonable result against the growth of KlebsiellaStaphylococcus aureus a gram-positive and spherical bac-terium leads to life-threatening diseases like pneumoniaosteomyelitis endocarditis and toxic shock syndrome Toxicshock syndrome is characterized by the sudden onset of highfever vomiting diarrhea and muscle aches followed by lowblood pressure (hypotension) which can lead to shock and
Bioinorganic Chemistry and Applications 13
log[g
(120572)T3]
minus95
minus90
minus85
minus80
minus75
10 15 20 25 30
Intercept = minus825
Ea = 1039
1000T (Kminus1)
(a)
log[g
(120572)T3]
minus78
minus80
minus82
minus84
minus86
minus88
minus90
minus92
minus94
minus96
minus76
Intercept = minus805
Ea = 1367
10 15 20 25 30
1000T (Kminus1)
(b)
log[g
(120572)T3]
minus77
minus78
minus79
minus80
minus81
minus82
minus83
minus84
minus85
minus86
minus87
minus88minus89
Intercept = minus849
Ea = 460
10 15 20 25 30
1000T (Kminus1)
(c)
minus78
minus80
minus82
minus84
minus86
minus7610 15 20 25 30
1000T (Kminus1)
log[g
(120572)T3]
Intercept = minus835
Ea = 1213
(d)
Figure 12 Freeman-Carroll plots (119864119886) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Table 6 Activation energies calculated by Phadnis-Deshpande method
Reaction mechanism model Energy of activation (119864119886) (kJmol)
BEF ligand BEFminusCu BEFminusNi BEFminusZnPower law 60932 62642 59691 54312Power law 121864 125284 119382 108625Phase boundary (contracting sphere) 16497 16816 16174 15009Phase boundary (contracting cylinder) 25894 26436 25383 23466Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 12135 13830 11756 07447
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 08090 09220 07837 04964
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 06067 06915 05878 03723
Valensi 2-dimensional diffusion 168354 171926 165034 152695Jander 3-dimensional diffusion 32995 33632 32349 30018Brounshtein-Ginstling 3-dimensional diffusion 56520 55015 55669 57981The values indicated in bold are closest to the 119864119886 value estimated by FC and SWmethods
14 Bioinorganic Chemistry and Applications
Table 7 Antibacterial activity of BEF ligand and its complexes
Compound Inhibition zone (mm)S sonnei E coli Klebsiella sp S aureus B subtilis S typhi
BEF ligand 15 13 13 14 15 12BEFndashCu 21 17 17 18 18 18BEFndashNi 18 15 18 17 20 15BEFndashZn 16 15 15 16 17 15Standard 26 28 26 25 27 28Control mdash mdash mdash mdash mdash mdashStandard amoxicillin control DMSO
Table 8 Antifungal activity of BEF ligand and its complexes
Compound Inhibition zone (mm)Aspergillus flavus Aspergillus niger Penicillium species Candida albicans Cryptococcus neoformans Mucorspecies
BEF ligand 14 12 12 13 11 12BEFndashCu 20 18 19 18 15 19BEFndashNi 17 14 17 15 13 13BEFndashZn 15 15 18 17 14 16Standard 20 21 19 21 18 22Control mdash mdash mdash mdash mdash mdashStandard fluconazole control DMSO
death There may be a rash resembling sunburn with peelingof skin The ligand and its complexes showed a humbleactivity against the growth of S aureus Bacillus subtilis arerod-shaped and nonpathogenic gram-positive bacteria TheBEF ligand and complexes showed superb activity againstthe growth of this bacterium Salmonella typhimurium is apathogenic gram-negative bacteria predominately found inthe intestinal lumen When the bacterial cells enter epithelialcells lining the intestine they cause host cell ruffling whichtemporarily damages the microvilli on the surface of the cellThis causes a rush of white blood cells into the mucosa andleads to diarrheaThe ligand and its metal complexes showeda moderate activity against the growth of the typhi species
A comparative account on the effect of antibacterialactivity against the chosen microbes indicates that the ligandand its three metal chelates show reasonable activity againstShigella sonnei (15 21 18 and 16mm) and Bacillus subtilis (1518 20 and 17mm) while the growth of other organisms ismoderately inhibited by the BEF ligand and its Cu2+ Ni2+and Zn2+ chelates The highest antibacterial action (21mm)has been observed for BEFndashCu2+ complex against Shigellasonnei
392 Antifungal Activity The antifungal activity of the BEFligand and its metal complexes has also given interestingresults and the growth inhibitions against the chosen fungalstrains are tabulated in Table 8 All the complexes and theirligand have an excellent activity against Aspergillus flavusa mold type fungal strain which may invade arteries of thelung or brain to cause infections and also produce a toxinAspergillus niger is one of the most common causes for
otomycosis The chelates and the ligand are found to havea reasonable activity for A niger Penicillium species causesinfection in humans and the resulting disease is known gener-ically as penicilliosis The ligand and the metal complexeshave wonderful activity against this species Further BEFndashCucomplex has a superior activity compared to the rest of othercomplexes Candida albicans is a diploid fungus and a causalagent of opportunistic oral and genital infections in humansand also emerged as an important cause of morbidity andmortality in immunocompromised patients The BEF ligandand its chelates possess a modest activity against C albicansover and above the standard Cryptococcus neoformans is anencapsulated yeast-like fungus that can live in both plantsand animals and cause lung infection The terpolymer ligandand its chelates have a fair activity against this fungal strainThe chelate compounds and the ligand havemoderate activityagainst Mucor species a filamentous fungus which causesseptic arthritis renal infections and pulmonary infections
From the antimicrobial results themetal complexes showhigher activity than their ligand which may be stronglydependent on the central metal ions and coordination num-bers metal chelates The higher activity due to the metal ionsshared with the donor atoms (N and S) of the thiazole ring ispresent in the ligand and the 120587-electron delocalization overthe chelate ring This effect increases the lipophilic characterof the metal ion which favors the permeation through thelipoid layers of the bacterial and fungal membranes [33 34]It is perceived that the factors such as solubility conductivitydipole moment and cell permeability may also contributeto the increased activity of the complexes [35 36] Fromthe results of the studies at 500 ppm concentration thecompounds establish better antimicrobial activity Hence it
Bioinorganic Chemistry and Applications 15
is an interesting result that a very low concentration of thecompound namely 500 ppm is enough to bring out aneffective inhibition against the chosen microbes
4 Conclusion
The synthesized 2-amino-6-nitro-benzothiazole-ethylene-diamine-formaldehyde terpolymer has acted as a ligandsuccessfully to form metal complexes The synthesized com-pounds were well characterized by various spectral andphysical analyses The morphological features suggest thatthe complexes are slightly more crystalline in nature thantheir parent ligandThe antibacterial and antifungal activitiesreveal that the terpolymer and its metal complexes can beactive against the selected bacterial and fungal strains Nearlyall of the compoundsmay suit well for drug delivery field afterchecking for their toxicology behaviour in thorough mannerThermal studies are also helpful to realize the standing capac-ity of the compounds which survive as antimicrobial coatingmaterials in various environmental conditions Because ofthe proven high stability nature and microbial preventioncapacity the BEF terpolymer and its Cu2+ Ni2+ and Zn2+complexes hold inadequate applications in biological fieldThe thermal stability of the terpolymer and its metal com-plexes was found greater From the thermodynamic andkinetic studies the abnormal low values of frequency factor(119885) indicate that the thermal decomposition reaction of BEFterpolymer and its metal complexes can be depicted as a slowreaction The BEF terpolymer and its metal complexes maybe following nearly a first order kinetics
Conflict of Interests
The authors certify that there is no conflict of interests withany financial organization regarding thematerial discussed inthe paper
Acknowledgments
The authors thank the Management and Principal ofOxford Engineering College Tiruchirappalli CoimbatoreInstitute of Technology Coimbatore Jamal Mohamed Col-lege (Autonomous) Tiruchirappalli Tamil Nadu and DrD Jeyakumar Scientist Central Electrochemical ResearchInstitute (CECRI-CSIR) Karaikudi Tamil Nadu for theirsupport and encouragement
References
[1] C U Pittman K S Ramachandran Jr and K R LowyerldquoSynthesis of fungicidal monomers polymers and latticesrdquoJournal of Coating Technology vol 54 pp 27ndash40 1982
[2] M N Patel J R Patel and D H Sutaria ldquoNovel co-ordinationpolychelatesrdquo Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry vol 24 no 8 pp 1297ndash1309 1994
[3] V V Ukey and H D Juneja ldquoSynthetic and spectroscopicstudies of chelate polymers involving azelaoyl bis-N-phenylhydroxamic acid with transition metal ionsrdquo Journal of AppliedPolymer Science vol 99 no 1 pp 273ndash278 2006
[4] S K-H Thiele and D R Wilson ldquoAlternate transition metalcomplex based diene polymerizationrdquo Polymer Reviews vol 43no 4 pp 581ndash628 2003
[5] N Nishat S Ahmad and T Ahamad ldquoSynthesis and character-ization of antibacterial polychelates of urea-formaldehyde resinwith Cr(III) Mn(II) Fe(III) Co(II) Ni(II) Cu(II) and Zn(II)metal ionsrdquo Journal of Applied Polymer Science vol 100 no 2pp 928ndash936 2006
[6] E Brzezinska G Koska and K Walczynski ldquoApplicationof thin-layer chromatographic data in quantitative structure-activity relationship assay of thiazole and benzothiazole deriva-tives with Hmdashantihistamine activityrdquo Journal of Chromatogra-phy A vol 1007 pp 145ndash155 2003
[7] M A R Ahamed and A R Burkanudeen ldquoMetal complexesof a novel terpolymer ligand synthesis spectral morphologythermal degradation kinetics and antimicrobial screeningrdquoJournal of Inorganic andOrganometallic Polymers andMaterialsvol 22 no 5 pp 1046ndash1061 2012
[8] B S Holla K V Malini V S Rao B K Sarojini and N SKumari ldquoSynthesis of some new 24-disubstituted thiazoles aspossible antibacterial and anti-inflammatory agentsrdquo EuropeanJournal of Medicinal Chemistry vol 38 no 3 pp 313ndash318 2003
[9] O I El-Sabbagh M M Baraka S M Ibrahim et al ldquoSynthesisand antiviral activity of new pyrazole and thiazole derivativesrdquoEuropean Journal of Medicinal Chemistry vol 44 no 9 pp3746ndash3753 2009
[10] A Andreani M Granaiola A Leoni A Locatelli R Morigiand M Rambaldi ldquoSynthesis and antitubercular activity ofimidazo[21-b]thiazolesrdquo European Journal of Medicinal Chem-istry vol 36 no 9 pp 743ndash746 2001
[11] E Yousif Y Farina K Kasar A Graisa and K Ayid ldquoCom-plexes of 2-thioacetic acid benzothiazole with somemetal ionsrdquoAmerican Journal of Applied Sciences vol 6 no 4 pp 582ndash5852009
[12] B P Mallikarjuna B S Sastry G V Suresh Kumar Y Rajen-draprasad S M Chandrashekar and K Sathisha ldquoSynthesis ofnew 4-isopropylthiazole hydrazide analogs and some derivedclubbed triazole oxadiazole ring systemsmdasha novel class ofpotential antibacterial antifungal and antitubercular agentsrdquoEuropean Journal of Medicinal Chemistry vol 44 pp 4739ndash4746 2009
[13] T Ahamad V Kumar and N Nishat ldquoNew class of anti-microbial agents synthesis characterization and anti-microbial activities of metal chelated polyureardquo Journal ofBiomedical Materials Research A vol 88 no 2 pp 288ndash2942009
[14] M V Patel J N Patel M B Dolia and R M Patel ldquoPolyether-ketones synthesis characterization and antimicrobial activityrdquoInternational Journal of Polymeric Materials and PolymericBiomaterials vol 54 no 11 pp 1059ndash1071 2005
[15] K R Alagawadi and S G Alegaon ldquoSynthesis characteriza-tion and antimicrobial activity evaluation of new 24-Thiazoli-dinediones bearing imidazo[21-b][134]thiadiazole moietyrdquoArabian Journal of Chemistry vol 4 no 4 pp 465ndash472 2011
[16] M Ashok B S Holla and N S Kumari ldquoConvenientone pot synthesis of some novel derivatives of thiazolo[23-b]dihydropyrimidinone possessing 4-methylthiophenyl moietyand evaluation of their antibacterial and antifungal activitiesrdquoEuropean Journal ofMedicinal Chemistry vol 42 no 3 pp 380ndash385 2007
16 Bioinorganic Chemistry and Applications
[17] T Ahamad V Kumar S Parveen and N Nishat ldquoIn vitroantibacterial and antifungal assay of poly-(ethylene oxamide-NN1015840-diacetate) and its polymer-metal complexesrdquo AppliedOrganometallic Chemistry vol 21 no 12 pp 1013ndash1021 2007
[18] R S Azarudeen M A R Ahamed and A R BurkanudeenldquoBiological and thermal investigations of polychelates derivedfrom a novel terpolymer ligandrdquo Journal of Polymer Researchvol 18 no 6 pp 1331ndash1341 2011
[19] R S Azarudeen and A R Burkanudeen ldquoSynthesis spectralmorphology thermal degradation kinetics and antibacterialstudies of terpolymermetal complexesrdquo Journal of Inorganic andOrganometallic Polymers and Materials vol 22 no 4 pp 791ndash806 2012
[20] R S Azarudeen and A R Burkanudeen ldquoStudies of newoligomer-metal complexes and their antibacterial activitiesrdquoPolymer International vol 62 no 3 pp 362ndash374 2013
[21] G S Devi A K Muthu D S Kumar S Rekha R Indhumathiand R Nandhini ldquoStudies on the antibacterial and antifungalactivities of the ethanolic extracts of Luffa cylindrica (Linn)fruitrdquo International Journal of Drug Development and Researchvol 1 pp 105ndash109 2013
[22] R M Silverstein and G C Bassler Spectrometric IdentificationofOrganic Compounds JohnWileyamp SonsNewYorkNYUSA2nd edition 1967
[23] Y-G Zhao H-Y Shen S-D Pan and M-Q Hu ldquoSyn-thesis characterization and properties of ethylenediamine-functionalized Fe
3O4magnetic polymers for removal of Cr(VI)
in wastewaterrdquo Journal of Hazardous Materials vol 182 no 1-3pp 295ndash302 2010
[24] Y R Sharma Elementary Organic Absorption Spectroscopy SChand amp Co Ltd New Delhi India 1980
[25] D Kivelson and R Neiman ldquoESR line shapes in glasses ofcopper complexesrdquoThe Journal of Chemical Physics vol 35 no1 pp 149ndash155 1961
[26] E Pretsch P Buhlmann and C Afflolter Structure Determi-nation of Organic Compounds Springer New York NY USA2000
[27] J L White Modern Magnetic Resonance Kluwer AcademicPress London UK 2006
[28] M M Patel M A Kapadia and J D Joshi ldquoThermal andcatalytic aspects of Ln(III) polymer-metal complexesrdquo PolymerInternational vol 58 no 7 pp 728ndash737 2009
[29] S Nanjundan C S J Selvamalar and R Jayakumar ldquoSynthesisand characterization of poly(3-acetyl-4-hydroxyphenyl acry-late) and its Cu(II) and Ni(II) complexesrdquo European PolymerJournal vol 40 no 10 pp 2313ndash2321 2004
[30] A V Nikolaev V A Logvinenco and L I Myachina ThermalAnalysis Academic Press New York NY USA 1969
[31] A Z El-Sonbati and M A Hefni ldquoPolymer complexes PartXXVImdashNovel mixed ligand poly-(5-vinyl salicylidene)-12-diaminobenzene complexesrdquo Polymer Degradation and Stabil-ity vol 43 no 1 pp 33ndash42 1994
[32] A S Aswar and N S Bhave ldquoThermal degradation studies ofsome new coordination polymersrdquo Polymer Degradation andStability vol 31 no 1 pp 115ndash124 1991
[33] T Ahamad V Kumar and N Nishat ldquoSynthesis characteri-zation and antimicrobial activity of transition metal chelatedthiourea-formaldehyde resinrdquo Polymer International vol 55no 12 pp 1398ndash1406 2006
[34] M M Patel M A Kapadia G P Patel and J D Joshi ldquoSynthe-sis characterization ion-exchange and antimicrobial study of
poly[(2-hydroxy-4-methoxybenzophenone) propylene] resinand its polychelates with lanthanides (III)rdquo Journal of AppliedPolymer Science vol 106 no 2 pp 1307ndash1317 2007
[35] M A Neelakantan S S Marriappan J Dharmaraja T Jeyaku-mar and K Muthukumaran ldquoSpectral XRD SEM and bio-logical activities of transition metal complexes of polydentateligands containing thiazole moietyrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 71 no 2 pp 628ndash635 2008
[36] G B Bagihalli S A Patil and P S Badami ldquoSynthesisphysicochemical investigation and biological studies of zinc(II)complexes with 124-triazole schiff basesrdquo Journal of the IranianChemical Society vol 6 no 2 pp 259ndash270 2009
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Inorganic ChemistryInternational Journal of
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Carbohydrate Chemistry
International Journal of
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Journal of
Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
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Analytical Methods in Chemistry
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Volume 2014
Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
SpectroscopyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Medicinal ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chromatography Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Applied ChemistryJournal of
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Analytical ChemistryInternational Journal of
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Quantum Chemistry
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ElectrochemistryInternational Journal of
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CatalystsJournal of
2 Bioinorganic Chemistry and Applications
A series of 4-isopropylthiazole-2-carbohydrazide ana-logs derived from clubbed oxadiazole-thiazole and triazole-thiazole derivatives have been synthesized and characterizedby Mallikarjuna et al [12] The synthesized compoundswere evaluated for their preliminary in vitro antibacterialantifungal and antitubercular activity againstMycobacteriumtuberculosis H
37Rv strain by broth dilution assay method
Ahamad et al [13] reported a new class of metal chelatedpolyurea for its excellent antimicrobial activity against Saureus E coli B subtilis and S typhi The Cu2+ chelatedpolyurea shows higher zone of inhibition than the otherones due to higher stability constant and may be used inbiomedical applications Patel et al [14] reported that thesynthesis of low molecular weight polymeric resins containsseveral functional groups in gaining importance to involvethe antimicrobial activity All the synthesized polymers wereexamined for the antimicrobial activity against bacteria(Escherichia coli Bacillus subtilis and Staphylococcus citreus)fungi (Aspergillus niger Sporotrichum pulverulentum andTrichoderma lignorum) and yeast (Candida utilis Saccha-romyces cerevisiae and Pichia stipitis) It was observed thatmost of the polymers could be used as antibacterial andantifungal agents Alagawadi and Alegaon [15] synthesizedseries of novel 5-substituted-24-thiazolidinedione deriva-tives and studied the antimicrobial screening tests whichreveal the new compounds that act as antibacterial andantifungal agents Ashok et al [16] accounted for the onepot synthesis of some novel derivatives of thiazolo[23-b]dihydropyrimidinone possessing 4-methylthiophenylmoi-ety and evaluation of their antibacterial and antifungalactivities They have exhibited moderate to excellent growthinhibition against the chosen bacteria and fungi due to thepresence of N and S donor atoms present in the antimicrobialagents Ahamad et al [17] studied the in vitro antibacte-rial and antifungal assay of poly-(ethylene oxamide-NN1015840-diacetate) and its polymer-metal complexes The polymer-metal complexes showed excellent antibacterial activitiesagainst both types of microorganisms the polymeric ligandwas also found to be effective but less so than the polymer-metal complexes On the basis of the antimicrobial behaviorthese polymers may be used as antifungal and antifoulingcoating materials in fields like life-saving medical devicesand the bottoms of ships Recently our research groupsynthesized new types of polymer and oligomer ligands andtheir transition metal complexes for their excellent thermalstability and antimicrobial activity [18ndash20]
The present paper aims to introduce the new 2-amino-6-nitro-benzothiazole-ethylenediamine-formaldehyde (BEF)terpolymer ligand and its complexes It provides thesynthesis characterization thermal properties and bio-logical activities of the 2-amino-6-nitro-benzothiazole-ethylenediamine-formaldehyde (BEF) terpolymer ligandand its complexes The physicochemical properties andcharacterization of the BEF terpolymer ligand and itscomplexes were carried out by elemental analysis molarconductivity magnetic susceptibilities GPC FTIR UV-Visible ESR 1H and 13C NMR SEM XRD and TGA Fromthe TGA data the various kinetic and thermodynamic
parameters were evaluated for the BEF terpolymer ligandand its complexes The decomposition model for thethermal degradation reaction was also proposed Theantimicrobial activities of the terpolymer ligand and itscomplexes were reported against six bacterial strains suchas Shigella sonnei Escherichia coli Klebsiella species (NCIM2719) Staphylococcus aureus (ATCC 25923) Bacillus subtilis(ATCC 6633) and Salmonella typhimurium (ATCC 23564)and six fungal strains such as Aspergillus flavus Aspergillusniger Penicillium species Candida albicans Cryptococcusneoformans andMucor species
2 Experimental
21 Materials 2-Amino-6-nitro-benzothiazole and ethyl-enediamine were procured from Sigma Aldrich USA andused as received Formaldehyde (37) was procured fromMerck India and used as receivedDouble distilledwaterwasused for all the experiments All other chemicals and metalsalts were of analytical grade and were used without furtherpurification
22 Synthesis of Terpolymer Ligand Acollectivemixture of 2-amino-6-nitro-benzothiazole (976 g 005M) and ethylene-diamine (812mL 005M) with formaldehyde (811mL01M) was taken as monomers in a clean round bottom flaskequipped with a mechanical stirrer and a refluxed condenserusing dimethyl formamide (DMF) as a reaction medium in1 1 2 mole ratio The homogeneous mixture was refluxed inan oil bath at 150 plusmn 2∘C with constant stirring for 6 h Afterthe reaction time was over the resultant mixture was cooledand then poured into crushed ice with vigorous shaking Theobtained precipitate was separated out by filtration washedwith hot water ether and methanol to remove the unreactedmonomers and recrystallized from tetrahydrofuran (THF)The route of synthesis for the BEF terpolymer is shown inScheme 1
23 Preparation of Metal Complexes The terpolymer metalcomplexes have been prepared using the synthesized terpoly-mers as ligand with few transition metal ions such as Cu2+Ni2+ and Zn2+ ionsThe BEF terpolymer (2 g) was taken in around bottom flask and immersed for 2 h in ethanol solutionfor swelling The cupric nitrate (1 g) was dissolved in ethanolsolution and then poured into round bottom flask equippedwith mechanical stirrer and a reflux condenser The reactionmixture was refluxed at 60∘C for 3 h The obtained colloidalprecipitate in the flask was separated out The product wasthen filtered off andwashed with ether and ethanol to removethe impuritiesThis process has been repeated several times toseparate the purified product The resultant purified samplewas air dried powdered and kept in vacuum desiccatorwith silica gel The same procedure was also followed for thepreparation of BEF complexes with Ni2+ and Zn2+ metal ionsin the form of their nitrate salts The scheme of preparationof the BEF complex with Cu2+ Ni2+ and Zn2+ metal ions isshown in Scheme 2
Bioinorganic Chemistry and Applications 3
O2N
O2N
N
2-Amino-6-nitro-benzothiazole
2-Amino-6-nitro-benzothiazole-Ethylenediamine-Formaldehyde terpolymer
[BEF terpolymer]
Ethylenediamine
DMFFormaldehyde
N
S
Sn
n
nNH2
NH NH NH
CH2
CH2 CH2 CH2 CH2
H HC
O
CH2NH2 NH2 2n+ +
150 plusmn 2∘C6h
Scheme 1 Reaction route of the BEF terpolymer ligand
60∘C
O2NBEF terpolymer ligand
BEF terpolymer metal complexes
EtOH
N
Sn
NH NH NHCH2 CH2 CH2 CH2
O2N
N
Sn
NH NH
M2
NHCH2 CH2 CH2 CH2
3 h reflux
M2+
[M = Cu(II) Ni(II) and Zn(II)]
Scheme 2 Reaction route of the BEF metal complexes
24 Elemental Analysis The elemental analysis has beencarried out using Elementar instrument model Vario ELIII Germany The percentage of elements such as carbon(C) hydrogen (H) nitrogen (N) and sulphur (S) presentin the 2-amino-6-nitro-benzothiazole-ethylenediamine-formaldehyde (BEF) terpolymer and its metal complexeswith the metal ion content was determined
25 Gel Permeation Chromatography The number average(119872119899) weight average (119872
119908) and size average (119872
119911)molecular
weights of terpolymer were measured by gel permeationchromatography (Shimadzu Japan) using tetrahydrofuran(THF) as a mobile phase and CLC polystyrene as a stationaryphase in the column
26 Spectral Analyses TheUV-Visible spectra of the terpoly-mers and its metal complexes were recorded in Shimadzu(model 1601PC) UV-Visible spectrophotometer Japan The
ESR spectra of the terpolymer and its metal complexeswere recorded in Bruker instrument model EleXsys E 500USA The FTIR spectra of the terpolymer and its metalcomplexeswere obtainedwithAvatar (model 330USA) FTIRspectrometer using KBr The 1H and 13C NMR spectra wererecorded on a Bruker 400MHz (USA) NMR spectrometerusing DMSO-d
6as a solvent
27 SEM and XRD Methods The surface analysis of theBEF terpolymer and its metal complexes was examined atdifferent magnifications by scanning electron microscopeusing Hitachi instrument model S-3000H Japan The XRDanalysis of the terpolymer and its metal complexes wasperformed using PANalytical instrument (XrsquoPert PRO TheNetherlands)
28 Thermogravimetric Analysis The thermal stability of theBEF terpolymer and its metal complexes was observed bythermogravimetric analysis using TA instruments model
4 Bioinorganic Chemistry and Applications
SDT Q600 USA at a heating rate of 20∘Cmin in a staticnitrogen atmosphere
281 Thermal Degradation Kinetics and Mechanism Sharp-Wentworth and Freeman-Carroll methods have beenemployed for the determination of kinetic and thermo-dynamic parameters such as order of reaction (119899) activationenergy (119864
119886) entropy change (Δ119878) free energy change
(Δ119865) apparent entropy (119878lowast) and frequency factor (119885)Phadnis-Deshpande method has also been used to proposethe thermal degradation mechanism for the synthesizedterpolymer and its metal complexes [20]
29 Antimicrobial Analysis by Disc Diffusion Method TheBEF terpolymer and its metal complexes were screened fortheir antimicrobial activity by disc diffusion method [21]against six bacterial strains such as Shigella sonneiEscherichiacoli Klebsiella species (NCIM 2719) Staphylococcus aureus(ATCC 25923) Bacillus subtilis (ATCC 6633) and Salmonellatyphimurium (ATCC 23564) and six fungal strains such asAspergillus flavus Aspergillus niger Penicillium species Can-dida albicans Cryptococcus neoformans and Mucor speciesAntimicrobial activity was tested by the filter paper discdiffusion technique involving the cultures of the selectedorganisms for 24 hMuellerHinton agar number 2 (HiMediaIndia) was used as the bacteriological medium and sterileyeast nitrogen base with 2 agar (Hi Media India) was usedas the fungal medium The test solutions of the terpolymerand its metal complexes were prepared in sterile dimethylsulfoxide (DMSO) solvent for the study The synthesized ter-polymer and its metal complexes were tested at different con-centrations ranging from 50 to 1000 ppm to find out the min-imum concentration of the terpolymer ligand and its metalcomplexes required for inhibiting the growth of microbes
Amoxicillin (100 120583gmL) was taken as the standard forantibacterial activity The organism was seeded into sterilenutrient agar medium by mixing one mL of inoculum with20mL sterile melted nutrient agar kept at 48ndash50∘C in a sterilepetri dish The medium was allowed to solidify first Thenthe test solutions the standard drugs and the blank wereimpregnated in whatman filter paper discs placed on thesolidified medium in the petri dish and left undisturbed for2 h at room temperatureThepetri disheswere then incubatedat 37∘C for 24 h and the zone of inhibition for the test samplesstandard and control (DMSO) was measured
Sterile yeast nitrogen base (Hi Media) with 2 agar wasinoculated by a rotating swab (soaked in standard inoculumsuspension) over the surface of the media Fluconazole(100mcgmL) was taken as the standard for antifungalactivity The test solution impregnated discs were placed onthe agar andwere incubated at 37∘C for 18 hThe zone of inhi-bition was measured by measuring the minimum dimensionof the zone of fungal growth around the filter paper disc
3 Results and Discussion
31 Physicochemical and Analytical Data The physicochem-ical and analytical data of the BEF terpolymer and its metal
complexes are given in Table 1 The BEF terpolymer is yellowin colour and itsmetal complexes are brown forCu2+ complexand yellow for Ni2+ and Zn2+ complexesThe yield of the BEFterpolymer ligand was 79 and the yield of Cu2+ Ni2+ andZn2+ complexes was 80 77 and 78 respectively Basedon the analytical data from the elemental analysis the empir-ical formula of the BEF terpolymer ligand and its metal com-plexes is found to be in good agreement with the calculatedelemental values of C H N S and M The amount of metalions present in the metal complexes indicates 1 2ML sto-ichiometry suggesting six coordination involving two coor-dinated water molecules for BEFndashCu BEFndashNi and BEFndashZncomplexes From the results the general empirical formulaof the repeating unit of the BEF terpolymer is C
11H13N5O2S
and of the metal complexes is C22H26N10O4S2Cusdot2H
2O
for BEFndashCu C22H26N10O4S2Nisdot2H
2O for BEFndashNi and
C22H26N10O4S2Znsdot2H
2O for BEFndashZn From the molar con-
ductance values the metal complexes were found to beelectrolytes
32 Molecular Weight Measurements The average molecularweight of the BEF terpolymer was determined by gel perme-ation chromatographyTheweight average (119872
119908) and number
average (119872119899)molecular weight of the terpolymer were found
to be 1941 and 1940 respectively The polydispersity index(119872119908119872119899) was found to be 10005 The average molecular
weight (119872119911) of the terpolymer was found to be 1942 The
polydispersity index (119872119911119872119908) of the terpolymer is 10005
The polydispersity index (119872119908119872119899) and (119872
119911119872119908) values for
the terpolymer indicate the narrow distribution of molecularweight in the terpolymer
33 FTIR Spectra The FTIR spectra of BEF terpolymerligand and its metal complexes are depicted in Figure 1 andthe data are presented in Table 2 The band frequencies andthe groups assigned to both terpolymer ligand and its metalcomplexes are based on the earlier literature [22 23] Theligand spectrum showed a band appearing in the range of3455ndash3297 cmminus1 is assigned to the ndashNH asymmetric andsymmetric vibrations The 268-trisubstituted benzothiazolering is confirmed by sharp and medium absorption bandsappearing between 1296 and 825 cmminus1 A strong band thatappeared at 1532 cmminus1 is due to the ndashNH bending vibrationA band that appeared at 2731 cmminus1 is assigned to the ndashCHstretching vibrations present in the aromatic ring The bandsappearing in the region of 3078ndash2936 cmminus1 are attributed tondashCH2asymmetric and symmetric vibrations present in the
terpolymer ligand The presence of ndashCH2bending vibration
in NndashCH2ndashCH2ndashN bridge in the spectrum is confirmed by
the absorption band that appeared at 1450 cmminus1In the spectra of BEF metal complexes the bands are
slightly broadened compared to the terpolymer ligand Theband that appeared at 1532 cmminus1 is assigned to ndashNH bendingvibrations in the ligand spectrum that is shifted to the lowerfrequencies (1521 to 1527 cmminus1) in the case of polymer-metalcomplexes This shift is due to the coordination of metalions through the lone pair of both nitrogen atoms present
Bioinorganic Chemistry and Applications 5
Table 1 Physicochemical and analytical data
Compound Empirical formula ofthe repeating unit Formula mass
Elemental analysis ()Λ (Ωminus1 cm2 molminus1)Found (calc)
C H N S MBEF ligand C11H13N5O2S 27936 4709 (4729) 416 (435) 2521 (2549) 1120 (1139) mdash mdashBEFndashCu C22H26N10O4S2Cusdot2H2O 65823 4071 (4092) 439 (462) 2174 (2194) 919 (927) 931 (962) 13205BEFndashNi C22H26N10O4S2Nisdot2H2O 65334 4025 (4037) 447 (479) 2129 (2146) 962 (983) 926 (945) 9837BEFndashZn C22H26N10O4S2Znsdot2H2O 66010 4023 (4052) 423 (445) 2138 (2153) 912 (929) 941 (970) 11329C carbon H hydrogen N nitrogen S sulphur and M metal ion
Table 2 FTIR data
Compound Observed frequencies (cmminus1)BEF ligand BEFndashCu BEFndashNi BEFndashZn
] NH (asym and sym) 3455minus3297 3408ndash3296 3348ndash3295 3345ndash3280] NH (bending) 1532 1527 1526 1521CH (stretching) 2731 2697 2712 2725] CH2 (asym and sym) 3078ndash2936 3093ndash2912 3098ndash2932 3087ndash2945] CH2 (bending in NndashCH2ndashCH2ndashN) 1450 1448 1449 1446268-tri substitution (benzothiazole) 1296minus825 1298ndash825 1293ndash827 1292ndash825] NrarrM mdash 432 433 433] CndashNO2 1505ndash1518 1503ndash1576 1524ndash1575 1513ndash1583] C=N 1540 1590 1586 1580] CndashSndashC 740 753 763 748
Tran
smitt
ance
()
(a)
4000 3500 3000 2500 2000 1500 1000 500
(b)
(c)
(d)
Wavenumber (cmminus1)
Figure 1 FTIR spectra of (a) BEF (b) BEFndashCu (c) BEFndashNi and (d)BEFndashZn
in the ethylenediamine moiety It is a clear evidence for theinvolvement of nitrogen atoms in the chelationThis is furthersupported by the appearance of ]NrarrM stretching vibrationat 432ndash433 cmminus1
34 Electronic and ESR Spectra and Magnetic MomentsThe electronic spectra of the BEF terpolymer and its metalcomplexes are shown in Figure 2 and the data are presentedin Table 3 The spectrum of the ligand showed two bands at
100
Abso
rban
ce
050
0400
Wavelength (nm)600200 800
(d)(c)(b)
(a) (d)((c)(b)((((
(a)aaaaa
Figure 2 Electronic spectra of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
260 and 370 nmThese observed positions for the absorptionbands have different intensitiesThe less intense band 260 nmis due to (120587 rarr 120587
lowast) allowed transition of chromophoregroups like NO
2 gtC=N and C=C which are in conjugation
with an aromatic nucleus (benzothiazole ring) and the moreintense band 370 nm may be due to (119899 rarr 120587
lowast) transition ofndashNH groupsThus 120587 rarr 120587lowast transition indicates the presence
6 Bioinorganic Chemistry and Applications
Table 3 UV-Visible ESR data and magnetic moments
Compound Transitions (cmminus1) Assignments Geometry ESR Magnetic moment (BM)119892II 119892
perp
BEF 260 nm 120587 rarr 120587lowast mdash mdash mdash mdash370 nm 119899 rarr 120587
lowast
BEFndashCu14295 1
119861119892rarr
2119864119892
Octahedral 221 211 18516465 1119861119892rarr
2119864119892
24580 Charge transfer
BEFndashNi12474 3119879
2119892(119865) larr 3119860
2119892(119865)
Octahedral mdash mdash 30514642 31198791119892(119865) larr 3119860
2119892(119865)
24370 31198791119892(119875) larr 3119860
2119892(119865)
BEFndashZn mdash mdash Octahedral mdash mdash Diamagnetic
0 1000
Inte
nsity
2000 3000 4000 5000 6000 7000G
Figure 3 ESR spectra of BEFndashCu complex
of aromatic nucleus and 119899 rarr 120587lowast transition indicates thepresence of ndashNH groups The electronic spectrum of BEFndashCu metal complex exhibited bands at 14295 16465 and24580 cmminus1 and the assignments are 1119861
119892rarr2119864119892 1119861119892
rarr2119864119892 and charge transfer spectra which lead to a distorted
octahedral geometry with the magnetic moment of 185 BMThe electronic spectrum of BEFndashNi exhibits three bands at12474 14642 and 24370 cmminus1 assigned to the spin allowedtransitions 3119879
2119892(119865) larr 3119860
2119892(119865) 3119879
1119892(119865) larr 3119860
2119892(119865) and
31198791119892(119875) larr 3
1198602119892(119865) in an octahedral environment with a
magnetic moment of 305 BMThe diamagnetic nature of theBEFndashZn is also confirmed with octahedral geometry Basedon the literature the geometry is assigned to all the metalcomplexes [24]
The ESR spectrum of BEFndashCu complex is shown inFigure 3 and its spectral data are presented in Table 3 Thespectrum provides useful information about the metal ionenvironment in the respective complexes The ESR spectrumof BEFndashCu metal complex showed that 119892
= 221 and
119892perp= 211 lead to an octahedral environment According to
Kivelson and Neimen [25] the bond between the ligand andthe metal possesses a more covalent character than ionic In
general both the parallel and the perpendicular 119892 values canbe used to calculate the 119866 value by the following equation
119866 =119892minus 2002
119892perpminus 2002
(1)
Using the above equation the 119866 value for BEFndashCu was192 which clearly indicates that the complex forms with astrong field ligand
35 Nuclear Magnetic Resonance The NMR (1H and 13C)spectra for BEF terpolymer ligand and its zinc metal complex(due to d9 and d8 configurations both NMR spectra forcopper and nickel metal complexes are complicated) wererecorded to elucidate the structure of the ligand and itscomplex
351 1H NMR Spectra The 1H NMR spectra of BEF ter-polymer ligand and its Zn2+ metal complex are shownin Figure 4 The signals obtained for the terpolymer andits metal complexes were interpreted on the basis of thedata available in the literature [22 26] The spectrum ofterpolymer showed that the signals appearing in the region of739ndash824 ppm are assigned to all the protons of the aromaticring A peak appearing at 250 is assigned to the methyleneprotons of the terpolymer ligand The terpolymer spectrumshowed a signal appearing at 472 ppm that is assigned tothe ndashNH protons of ethylenediamine moiety and the peakappearing at 865 ppm is assigned to ndashNH proton of thiazolering A weak signal appearing at 302 ppmmay be assigned toethylenic protons of an ArndashCH
2ndashNHndashCH
2moiety
The spectrum of the Zn2+ complex showed multiplet inthe range of 740ndash824 ppm is assigned to the aromatic protonsand the methylene protons appeared at 215ndash250 ppm Thesignal obtained at 508 ppm is assigned to ndashNH protons ofethylenediamine and this shift from its ligand gives a clearevidence for the complexation of the ligand with the metalions through the lone pair of nitrogen of ethylenediaminemoiety
352 13C NMR Spectra The 13C NMR spectra of the BEFterpolymer ligand and its Zn2+ metal complex are shown in
Bioinorganic Chemistry and Applications 7
(ppm)
12345678910
(a)
(ppm)1 0234567891011
(b)
Figure 4 1H-NMR spectra of (a) BEF ligand and (b) BEFndashZn
200 180 160 140 120 100 80 60 40 20 0(ppm)
(a)
200 180 160 140 120 100 80 60 40 20 0(ppm)
(b)
Figure 5 13C-NMR spectra of (a) BEF ligand and (b) BEFndashZn
O2N S
N
NH NH
M
NHCH2 CH2 CH2 CH2
n
O2NS
NNH NH NHCH2 CH2 CH2 CH2
n
H2OH2O
[M = Cu(II) Ni(II) and Zn(II)]
Figure 6 Proposed geometry of BEF metal complexes
Figure 5 The observed chemical shifts are assigned on thebasis of the literature [22 27]The spectrum of ligand showedthat the corresponding peaks at 1717 1585 1315 1219 14061167 and 1253 ppm are attributed to the aromatic carbonsof the benzothiazole ring The peak appearing at 502 ppmis assigned to the methylenic carbon of NHndashCH
2bridge in
the ligand The spectrum of Zn2+ complex showed the peaksfor aromatic ring in the same region which was appearingin its parent ligand The shifting of the methylene carbonfrom 502 to 561 ppm from its ligand clearly suggests that the
coordination takes place between the nitrogen atoms of theethylenediamine moiety
From the elemental and spectral data (FTIR UV-VisESR and NMR (1H and 13C)) the structure of the BEF ter-polymer ligand and its metal complexes has been confirmedThe proposed geometry of the BEF complexes is shown inFigure 6
36 Surface Analysis The SEM is applied to understandthe surface features of the polymeric materials The SEM
8 Bioinorganic Chemistry and Applications
(a) (b)
(c) (d)
(e)
Figure 7 SEM images of (a) and (b) BEF ligand (c) BEFndashCu (d) BEFndashNi and (e) BEFndashZn
photographs in times1000 and times2000 magnifications for BEFligand and times3000 magnifications for BEF complexes areshown in Figure 7 The white bar at the bottom of the SEMphotographs represents the scale The SEM photographs ofthe BEF terpolymer ligand show leaf like appearance Thescattered structure of the terpolymer establishes a transitionstate between the crystalline and the amorphous phases [28]
Themorphology of BEF terpolymer resin exhibits growthof crystals from polymer solutions corresponding to the
most prominent organization in polymers on a large scalewith spherulites Ideally spherulites are the aggregates ofsubmicroscopic size particles Spherulites are characterizedby secondary structural features such as faint corrugationsThe SEM photographs of polymers have an appreciableamorphous fraction with a small amount of shallow pitsThe surface of BEF metal complexes contributes to greatersegments of crystalline regions compared to their parentligand which may arise from the contraction of the voids by
Bioinorganic Chemistry and Applications 9
Inte
nsity
(au
)
0 20 40 60 802120579
(a)
Inte
nsity
(au
)
0 20 40 60 802120579
(b)
Inte
nsity
(au
)
0 20 40 60 802120579
(c)
Inte
nsity
(au
)
0 20 40 60 802120579
(d)
Figure 8 XRD patterns of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
the cooperative contribution of the ligand for complexationwith metal ions or the disappearance of the voids in therearrangement of polymer chains for complexation withmetal ions This is a further evidence for the complexationof BEF terpolymer with metal ions
37 XRD Studies X-ray diffraction (XRD) patterns of BEFand its metal complexes are shown in Figure 8 It provides adetailed comparative account of the behavior of the terpoly-mer and itsmetal complexesThepattern of BEF ligand showsthe main characteristic peak and broad shoulder In view ofthe relative half value width it may be concluded that thepolymer is partially crystalline and the broad characteristicpeak indicates the amorphous nature of the terpolymerTherefore the BEF terpolymer has transition state betweenamorphous state and crystalline state whereas its metalchelates possess crystalline nature The enhanced crystallinebehavior of the BEF complexes may be due to the insertion ofmetal ions with their parent ligand [29]
38 Thermal Stability Thermal stability of the BEF terpoly-mer and its metal complexes was analyzed by thermogravi-metric analysis (TGA) The thermograms of the terpolymer
and its metal complexes are shown in Figure 9 and their per-centages of weight loss at various temperatures are presentedin Table 4
381Thermal Stability of BEF Terpolymer From the thermo-gram of BEF terpolymer there were three stages of degra-dation (200ndash320∘C 320ndash580∘C and 580ndash835∘C) observedThe first stage of degradation was observed between 200∘Cand 320∘C (found 5883 calc 5794) which reveals thedegradation of the benzothiazole ring The second stageof degradation begins at 320∘C and ends at 580∘C (found1003 calc 0931) which may be due to the eliminationof cross-linkages The third and final stage of degradation isobserved above 580∘C and continued up to 825∘C (found2506 calc 2473) which can be attributed to the weightloss of aliphatic group (ethylenediamine moiety) from theBEF terpolymer
382 Thermal Stability of BEF Metal Complexes In generalthe water of hydration may be considered as either crystalwater molecules or coordination water molecules Accordingto Nikolaev et al [30] water eliminated below 150∘C can beconsidered as crystal or lattice water and water eliminated
10 Bioinorganic Chemistry and Applications
Table 4 TGA data for thermal stability
Compound Percentage of weight loss at various temperatures11987950
lowast (∘C) 119879maxlowastlowast (∘C)
100 200 300 400 500 600 700 800 (∘C)BEF ligand 0153 0365 4414 6236 6718 7140 8224 9442 310 825BEFminusCu 0194 1432 3180 4301 4996 5549 6686 8122 500 860BEFminusNi 0893 1660 3735 4935 6460 8767 mdash mdash 405 650BEFminusZn 1464 2262 3833 4616 5726 6492 7614 9129 425 830lowastTemperature of 50 weight loss lowastlowastmaximum decomposition temperature
80
60
40
20
0
0
(a)(b)
(c)(d)
200 400 600 800 1000
100
Wei
ght (
)
Temperature (∘C)
Figure 9 TGA of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d)BEFndashZn
above 150∘C may be due to its coordination to the metalatom present in chelates In the present study in the case ofBEFndashCu2+ Ni2+ and Zn2+ complexes the removal of waterfrom the complex was completed within 150∘C These watermolecules are probably crystal or lattice water moleculesTheremoval of water molecules observed in the range of 150ndash200∘C (found 559ndash608 calc 545ndash551) of all the metalchelates is due to the elimination of two coordinated watermolecules These observations further confirm the distortedoctahedral geometry of BEF metal complexes
The thermogravimetric curves of all the BEF metalchelates showed two degradation steps after loss of watermolecules whichmay indicate that the first step (200ndash600∘C)is faster than the second step (600ndash860∘C) This may bedue to the fact that the noncoordinated part of the liganddecomposes firstwhile the coordinated part decomposes laterand finally it may form the representative metal oxides Theweight of the residues confirms fairly well that ofmetal oxides(found 1247ndash1362 calc 1143ndash1232)
The thermal degradation data of the BEF terpolymerand its metal complexes reveal that the polymeric complexesshow better stability than the BEF terpolymer due to thecoordination of metal ions The order of thermal stability ofthe BEF polymer and its complexes is BEFndashCu2+ gt BEFndashZn2+ gt BEF ligand gt BEFndashNi2+ The greater stability of themetal complexes may be due to the coordination and theenhanced cross linking nature with crowd effect of the metal
complexes [31] In the case of Ni2+ complex the degradationoccurred exceptionally at low temperature compared to theirligand which may be due to the oxidation of polymer by thecatalytic action of the metal ion [32]
383 Thermal Kinetics
(1) Sharp-Wentworth and Freeman-Carroll Method Ther-mal kinetic analysis was performed using Sharp-Wentworthmethod and Freeman-Carroll methods The activationenergy (119864
119886) and order of reaction (119899) plots for BEF terpoly-
mer ligand and its metal complexes by Sharp-Wentworthand Freeman-Carroll methods are shown in Figures 10 11and 12 The expressions used to calculate the kinetic andthermodynamic parameters are presented as follows
(i) Entropy change (Δ119878)
Intercept = log 119870119877
ℎΦ119864119886
+Δ119878
2303119877 (2)
where 119870 = 13806 times 10minus16 ergdegmole 119877 =
1987 caldegmole (8314 JKMol) ℎ = 6625 times
10minus27 erg sec Φ = 0166 Δ119878 = change in entropyand 119864
119886= activation energy from graph
(ii) Free energy change (Δ119865)
Δ119865 = Δ119867 minus 119879Δ119878 (3)
where Δ119867 = enthalpy change = activation energy 119879 =temperature in119870 and Δ119878 = result from (2)
(iii) Frequency factor (119885)
11986123
=log119885119864
119886
119877Φ (4)
11986123
= log 3 + log [1 minus 3radic1 minus 120572] minus log119901 (119909) (5)
where 119885 is the frequency factor 119861 is calculatedfrom (5) log119901(119909) is calculated from Doylersquos tablecorresponding to activation energy and 120572 is degreeof transformation (120572 = 119908119882
119888)
(iv) Apparent entropy (119878lowast)
119878lowast= 2303 log 119885ℎ
119877119879lowast (6)
where119885 is calculated from (4) and 119879lowast is half decom-position temperature
Bioinorganic Chemistry and Applications 11
1000T (Kminus1)
Intercept = minus535
minus45
minus50
minus55
minus60
minus65
minus70
minus75
minus80
10 15 20 25 30
Ea = 952
log[
(dC
dT
)(1
minusC
)]
(a)
minus64
minus62
minus60
minus58
minus56
minus54
minus52
1000T (Kminus1)10 15 20 25 30
Intercept = minus527
Ea = 1297
log[
(dC
dT
)(1
minusC
)]
(b)
minus64
minus62
minus50
minus52
minus54
minus56
minus58
minus60
1000T (Kminus1)10 15 20 25 30
Intercept = minus513
Ea = 693
log[
(dC
dT
)(1
minusC
)]
(c)
minus50
minus51
minus52
minus53
minus54
minus55
minus56
minus57
minus58
minus59
1000T (Kminus1)10 15 20 25 30
Intercept = minus538
Ea = 1108
log[
(dC
dT
)(1
minusC
)]
(d)
Figure 10 Sharp-Wentworth plots of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Table 5 Kinetic and thermodynamic parameters data
CompoundActivation energy
(119864119886kJmolminus1) Entropy change
(Δ119878J)Free energy
change (Δ119865kJ)Frequency
factor (119885sminus1)Apparent
entropy (119878lowastJ)Order of
reaction (119899)lowastSW lowastlowastFC
BEF ligand 952 1039 minus15811 5940 1310 minus2295 090BEFminusCu 1297 1367 minus15425 9079 1205 minus2331 104BEFminusNi 693 460 minus16290 7057 1537 minus2294 093BEFminusZn 1108 1213 minus16001 8013 1243 minus2318 102lowastSW Sharp-Wentworth lowastlowastFC Freeman-Carroll
Further from the knowledge of activation energy cal-culated by Freeman-Carroll method it is possible to eval-uate the values of various thermodynamic parameters Theorder of reaction (119899) and activation energy (119864
119886) and the
thermodynamic parameters such as frequency factor (119885)entropy change (Δ119878) free energy change (Δ119865) and apparententropy (119878lowast) are presented inTable 5The119864
119886values calculated
by SW and FC methods are in good agreement with eachother The order of activation energies for BEF ligand andits Cu2+ Ni2+ and Zn2+ complexes is parallel to the orderof their thermal stability [32] The values of thermodynamic
parameters were comparable indicating a common modeof decomposition reaction The abnormal low values offrequency factor (119885) indicate that the decomposition reactionof BEF terpolymer and its metal complexes can be depictedas a slow reaction The order of reactions (119899) of BEF ligandand its metal complexes is found to be 090 104 093 and102 respectively Hence the BEF terpolymer and its mealcomplexes may be following nearly a first order kinetics
(2) Phadnis-Deshpande Method The activation energiescalculated for BEF ligand and its metal complexes using
12 Bioinorganic Chemistry and Applications
minus00012minus00010minus00008minus00006minus00004minus00002minus00000
26242220181614121008060402
log(dWdt)
(1T)
n = 090
logW
r
logWr
(a)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
20
19
18
17
16
15
14
13
12
11
10
log(dWdt)
(1T)
n = 104
logWr
logW
r
(b)
15
16
17
18
19
14
13
12
11
10
09
log(dWdt)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
(1T)
n = 093logW
r
logWr
(c)
15
16
17
18
14
13
12
11
10
log(dWdt)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
(1T)
n = 102
logW
r
logWr
(d)
Figure 11 Freeman-Carroll plots (119899) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Phadnis-Deshpande method are presented in Table 6 Fromthe 119864
119886values it is possible to propose the degradation
reactionmechanism using PDmethod Further the 119864119886values
calculated by PD method are in good agreement with FCand SW methods Based on the closest 119864
119886values calculated
by PD SW and FC methods the Power law mechanismsuits very well for the BEF ligand and BEFndashCu and BEFndashZn metal complexes However BEFndashNi complex follows theBrounshtein-Ginstling 3-dimensional diffusion mechanism
39 Biological Studies
391 Antibacterial Activity To determine the antibacterialactivity of the BEF terpolymer and its Cu2+ Ni2+ andZn2+ complexes the disc diffusion method was used withamoxicillin as the standard antibiotic The prepared com-pounds were tested against Shigella sonnei Escherichia coliKlebsiella species Staphylococcus aureus Bacillus subtilis andSalmonella typhimuriummicroorganisms
Table 7 contains the screening results corresponding tothe polymeric ligand and its metal complexes with fairinhibition of growth against the tested organisms Shigella
sonnei is a nonmotile non-spore-forming and facultativeanaerobic gram-negative bacterium Shigella bacteria multi-ply within colonic epithelial cells and cause mucosal ulcer-ation inflammation bleeding high fever malaise diarrheaand tenesmus The ligand and its metal complexes showeda reasonable activity against the S sonnei species E coliis an aerobic gram-negative and rod shaped bacteriumInfection of E coli can lead to bloody diarrhea and kidneyfailureThe polymeric ligand and its complexes hold amodestactivity against the E coli Klebsiella is a genus of nonmotileand gram-negative bacteria that infects sites such as nasalpassages liver lung urinary tract bloodstream eye boneand joints It causes a wide range of disease states notablypneumonia septicemia soft tissue infections biliary tractinfection infection of the upper and lower respiratory tractand liver abscess The BEF ligand and its metal complexesshowed a reasonable result against the growth of KlebsiellaStaphylococcus aureus a gram-positive and spherical bac-terium leads to life-threatening diseases like pneumoniaosteomyelitis endocarditis and toxic shock syndrome Toxicshock syndrome is characterized by the sudden onset of highfever vomiting diarrhea and muscle aches followed by lowblood pressure (hypotension) which can lead to shock and
Bioinorganic Chemistry and Applications 13
log[g
(120572)T3]
minus95
minus90
minus85
minus80
minus75
10 15 20 25 30
Intercept = minus825
Ea = 1039
1000T (Kminus1)
(a)
log[g
(120572)T3]
minus78
minus80
minus82
minus84
minus86
minus88
minus90
minus92
minus94
minus96
minus76
Intercept = minus805
Ea = 1367
10 15 20 25 30
1000T (Kminus1)
(b)
log[g
(120572)T3]
minus77
minus78
minus79
minus80
minus81
minus82
minus83
minus84
minus85
minus86
minus87
minus88minus89
Intercept = minus849
Ea = 460
10 15 20 25 30
1000T (Kminus1)
(c)
minus78
minus80
minus82
minus84
minus86
minus7610 15 20 25 30
1000T (Kminus1)
log[g
(120572)T3]
Intercept = minus835
Ea = 1213
(d)
Figure 12 Freeman-Carroll plots (119864119886) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Table 6 Activation energies calculated by Phadnis-Deshpande method
Reaction mechanism model Energy of activation (119864119886) (kJmol)
BEF ligand BEFminusCu BEFminusNi BEFminusZnPower law 60932 62642 59691 54312Power law 121864 125284 119382 108625Phase boundary (contracting sphere) 16497 16816 16174 15009Phase boundary (contracting cylinder) 25894 26436 25383 23466Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 12135 13830 11756 07447
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 08090 09220 07837 04964
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 06067 06915 05878 03723
Valensi 2-dimensional diffusion 168354 171926 165034 152695Jander 3-dimensional diffusion 32995 33632 32349 30018Brounshtein-Ginstling 3-dimensional diffusion 56520 55015 55669 57981The values indicated in bold are closest to the 119864119886 value estimated by FC and SWmethods
14 Bioinorganic Chemistry and Applications
Table 7 Antibacterial activity of BEF ligand and its complexes
Compound Inhibition zone (mm)S sonnei E coli Klebsiella sp S aureus B subtilis S typhi
BEF ligand 15 13 13 14 15 12BEFndashCu 21 17 17 18 18 18BEFndashNi 18 15 18 17 20 15BEFndashZn 16 15 15 16 17 15Standard 26 28 26 25 27 28Control mdash mdash mdash mdash mdash mdashStandard amoxicillin control DMSO
Table 8 Antifungal activity of BEF ligand and its complexes
Compound Inhibition zone (mm)Aspergillus flavus Aspergillus niger Penicillium species Candida albicans Cryptococcus neoformans Mucorspecies
BEF ligand 14 12 12 13 11 12BEFndashCu 20 18 19 18 15 19BEFndashNi 17 14 17 15 13 13BEFndashZn 15 15 18 17 14 16Standard 20 21 19 21 18 22Control mdash mdash mdash mdash mdash mdashStandard fluconazole control DMSO
death There may be a rash resembling sunburn with peelingof skin The ligand and its complexes showed a humbleactivity against the growth of S aureus Bacillus subtilis arerod-shaped and nonpathogenic gram-positive bacteria TheBEF ligand and complexes showed superb activity againstthe growth of this bacterium Salmonella typhimurium is apathogenic gram-negative bacteria predominately found inthe intestinal lumen When the bacterial cells enter epithelialcells lining the intestine they cause host cell ruffling whichtemporarily damages the microvilli on the surface of the cellThis causes a rush of white blood cells into the mucosa andleads to diarrheaThe ligand and its metal complexes showeda moderate activity against the growth of the typhi species
A comparative account on the effect of antibacterialactivity against the chosen microbes indicates that the ligandand its three metal chelates show reasonable activity againstShigella sonnei (15 21 18 and 16mm) and Bacillus subtilis (1518 20 and 17mm) while the growth of other organisms ismoderately inhibited by the BEF ligand and its Cu2+ Ni2+and Zn2+ chelates The highest antibacterial action (21mm)has been observed for BEFndashCu2+ complex against Shigellasonnei
392 Antifungal Activity The antifungal activity of the BEFligand and its metal complexes has also given interestingresults and the growth inhibitions against the chosen fungalstrains are tabulated in Table 8 All the complexes and theirligand have an excellent activity against Aspergillus flavusa mold type fungal strain which may invade arteries of thelung or brain to cause infections and also produce a toxinAspergillus niger is one of the most common causes for
otomycosis The chelates and the ligand are found to havea reasonable activity for A niger Penicillium species causesinfection in humans and the resulting disease is known gener-ically as penicilliosis The ligand and the metal complexeshave wonderful activity against this species Further BEFndashCucomplex has a superior activity compared to the rest of othercomplexes Candida albicans is a diploid fungus and a causalagent of opportunistic oral and genital infections in humansand also emerged as an important cause of morbidity andmortality in immunocompromised patients The BEF ligandand its chelates possess a modest activity against C albicansover and above the standard Cryptococcus neoformans is anencapsulated yeast-like fungus that can live in both plantsand animals and cause lung infection The terpolymer ligandand its chelates have a fair activity against this fungal strainThe chelate compounds and the ligand havemoderate activityagainst Mucor species a filamentous fungus which causesseptic arthritis renal infections and pulmonary infections
From the antimicrobial results themetal complexes showhigher activity than their ligand which may be stronglydependent on the central metal ions and coordination num-bers metal chelates The higher activity due to the metal ionsshared with the donor atoms (N and S) of the thiazole ring ispresent in the ligand and the 120587-electron delocalization overthe chelate ring This effect increases the lipophilic characterof the metal ion which favors the permeation through thelipoid layers of the bacterial and fungal membranes [33 34]It is perceived that the factors such as solubility conductivitydipole moment and cell permeability may also contributeto the increased activity of the complexes [35 36] Fromthe results of the studies at 500 ppm concentration thecompounds establish better antimicrobial activity Hence it
Bioinorganic Chemistry and Applications 15
is an interesting result that a very low concentration of thecompound namely 500 ppm is enough to bring out aneffective inhibition against the chosen microbes
4 Conclusion
The synthesized 2-amino-6-nitro-benzothiazole-ethylene-diamine-formaldehyde terpolymer has acted as a ligandsuccessfully to form metal complexes The synthesized com-pounds were well characterized by various spectral andphysical analyses The morphological features suggest thatthe complexes are slightly more crystalline in nature thantheir parent ligandThe antibacterial and antifungal activitiesreveal that the terpolymer and its metal complexes can beactive against the selected bacterial and fungal strains Nearlyall of the compoundsmay suit well for drug delivery field afterchecking for their toxicology behaviour in thorough mannerThermal studies are also helpful to realize the standing capac-ity of the compounds which survive as antimicrobial coatingmaterials in various environmental conditions Because ofthe proven high stability nature and microbial preventioncapacity the BEF terpolymer and its Cu2+ Ni2+ and Zn2+complexes hold inadequate applications in biological fieldThe thermal stability of the terpolymer and its metal com-plexes was found greater From the thermodynamic andkinetic studies the abnormal low values of frequency factor(119885) indicate that the thermal decomposition reaction of BEFterpolymer and its metal complexes can be depicted as a slowreaction The BEF terpolymer and its metal complexes maybe following nearly a first order kinetics
Conflict of Interests
The authors certify that there is no conflict of interests withany financial organization regarding thematerial discussed inthe paper
Acknowledgments
The authors thank the Management and Principal ofOxford Engineering College Tiruchirappalli CoimbatoreInstitute of Technology Coimbatore Jamal Mohamed Col-lege (Autonomous) Tiruchirappalli Tamil Nadu and DrD Jeyakumar Scientist Central Electrochemical ResearchInstitute (CECRI-CSIR) Karaikudi Tamil Nadu for theirsupport and encouragement
References
[1] C U Pittman K S Ramachandran Jr and K R LowyerldquoSynthesis of fungicidal monomers polymers and latticesrdquoJournal of Coating Technology vol 54 pp 27ndash40 1982
[2] M N Patel J R Patel and D H Sutaria ldquoNovel co-ordinationpolychelatesrdquo Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry vol 24 no 8 pp 1297ndash1309 1994
[3] V V Ukey and H D Juneja ldquoSynthetic and spectroscopicstudies of chelate polymers involving azelaoyl bis-N-phenylhydroxamic acid with transition metal ionsrdquo Journal of AppliedPolymer Science vol 99 no 1 pp 273ndash278 2006
[4] S K-H Thiele and D R Wilson ldquoAlternate transition metalcomplex based diene polymerizationrdquo Polymer Reviews vol 43no 4 pp 581ndash628 2003
[5] N Nishat S Ahmad and T Ahamad ldquoSynthesis and character-ization of antibacterial polychelates of urea-formaldehyde resinwith Cr(III) Mn(II) Fe(III) Co(II) Ni(II) Cu(II) and Zn(II)metal ionsrdquo Journal of Applied Polymer Science vol 100 no 2pp 928ndash936 2006
[6] E Brzezinska G Koska and K Walczynski ldquoApplicationof thin-layer chromatographic data in quantitative structure-activity relationship assay of thiazole and benzothiazole deriva-tives with Hmdashantihistamine activityrdquo Journal of Chromatogra-phy A vol 1007 pp 145ndash155 2003
[7] M A R Ahamed and A R Burkanudeen ldquoMetal complexesof a novel terpolymer ligand synthesis spectral morphologythermal degradation kinetics and antimicrobial screeningrdquoJournal of Inorganic andOrganometallic Polymers andMaterialsvol 22 no 5 pp 1046ndash1061 2012
[8] B S Holla K V Malini V S Rao B K Sarojini and N SKumari ldquoSynthesis of some new 24-disubstituted thiazoles aspossible antibacterial and anti-inflammatory agentsrdquo EuropeanJournal of Medicinal Chemistry vol 38 no 3 pp 313ndash318 2003
[9] O I El-Sabbagh M M Baraka S M Ibrahim et al ldquoSynthesisand antiviral activity of new pyrazole and thiazole derivativesrdquoEuropean Journal of Medicinal Chemistry vol 44 no 9 pp3746ndash3753 2009
[10] A Andreani M Granaiola A Leoni A Locatelli R Morigiand M Rambaldi ldquoSynthesis and antitubercular activity ofimidazo[21-b]thiazolesrdquo European Journal of Medicinal Chem-istry vol 36 no 9 pp 743ndash746 2001
[11] E Yousif Y Farina K Kasar A Graisa and K Ayid ldquoCom-plexes of 2-thioacetic acid benzothiazole with somemetal ionsrdquoAmerican Journal of Applied Sciences vol 6 no 4 pp 582ndash5852009
[12] B P Mallikarjuna B S Sastry G V Suresh Kumar Y Rajen-draprasad S M Chandrashekar and K Sathisha ldquoSynthesis ofnew 4-isopropylthiazole hydrazide analogs and some derivedclubbed triazole oxadiazole ring systemsmdasha novel class ofpotential antibacterial antifungal and antitubercular agentsrdquoEuropean Journal of Medicinal Chemistry vol 44 pp 4739ndash4746 2009
[13] T Ahamad V Kumar and N Nishat ldquoNew class of anti-microbial agents synthesis characterization and anti-microbial activities of metal chelated polyureardquo Journal ofBiomedical Materials Research A vol 88 no 2 pp 288ndash2942009
[14] M V Patel J N Patel M B Dolia and R M Patel ldquoPolyether-ketones synthesis characterization and antimicrobial activityrdquoInternational Journal of Polymeric Materials and PolymericBiomaterials vol 54 no 11 pp 1059ndash1071 2005
[15] K R Alagawadi and S G Alegaon ldquoSynthesis characteriza-tion and antimicrobial activity evaluation of new 24-Thiazoli-dinediones bearing imidazo[21-b][134]thiadiazole moietyrdquoArabian Journal of Chemistry vol 4 no 4 pp 465ndash472 2011
[16] M Ashok B S Holla and N S Kumari ldquoConvenientone pot synthesis of some novel derivatives of thiazolo[23-b]dihydropyrimidinone possessing 4-methylthiophenyl moietyand evaluation of their antibacterial and antifungal activitiesrdquoEuropean Journal ofMedicinal Chemistry vol 42 no 3 pp 380ndash385 2007
16 Bioinorganic Chemistry and Applications
[17] T Ahamad V Kumar S Parveen and N Nishat ldquoIn vitroantibacterial and antifungal assay of poly-(ethylene oxamide-NN1015840-diacetate) and its polymer-metal complexesrdquo AppliedOrganometallic Chemistry vol 21 no 12 pp 1013ndash1021 2007
[18] R S Azarudeen M A R Ahamed and A R BurkanudeenldquoBiological and thermal investigations of polychelates derivedfrom a novel terpolymer ligandrdquo Journal of Polymer Researchvol 18 no 6 pp 1331ndash1341 2011
[19] R S Azarudeen and A R Burkanudeen ldquoSynthesis spectralmorphology thermal degradation kinetics and antibacterialstudies of terpolymermetal complexesrdquo Journal of Inorganic andOrganometallic Polymers and Materials vol 22 no 4 pp 791ndash806 2012
[20] R S Azarudeen and A R Burkanudeen ldquoStudies of newoligomer-metal complexes and their antibacterial activitiesrdquoPolymer International vol 62 no 3 pp 362ndash374 2013
[21] G S Devi A K Muthu D S Kumar S Rekha R Indhumathiand R Nandhini ldquoStudies on the antibacterial and antifungalactivities of the ethanolic extracts of Luffa cylindrica (Linn)fruitrdquo International Journal of Drug Development and Researchvol 1 pp 105ndash109 2013
[22] R M Silverstein and G C Bassler Spectrometric IdentificationofOrganic Compounds JohnWileyamp SonsNewYorkNYUSA2nd edition 1967
[23] Y-G Zhao H-Y Shen S-D Pan and M-Q Hu ldquoSyn-thesis characterization and properties of ethylenediamine-functionalized Fe
3O4magnetic polymers for removal of Cr(VI)
in wastewaterrdquo Journal of Hazardous Materials vol 182 no 1-3pp 295ndash302 2010
[24] Y R Sharma Elementary Organic Absorption Spectroscopy SChand amp Co Ltd New Delhi India 1980
[25] D Kivelson and R Neiman ldquoESR line shapes in glasses ofcopper complexesrdquoThe Journal of Chemical Physics vol 35 no1 pp 149ndash155 1961
[26] E Pretsch P Buhlmann and C Afflolter Structure Determi-nation of Organic Compounds Springer New York NY USA2000
[27] J L White Modern Magnetic Resonance Kluwer AcademicPress London UK 2006
[28] M M Patel M A Kapadia and J D Joshi ldquoThermal andcatalytic aspects of Ln(III) polymer-metal complexesrdquo PolymerInternational vol 58 no 7 pp 728ndash737 2009
[29] S Nanjundan C S J Selvamalar and R Jayakumar ldquoSynthesisand characterization of poly(3-acetyl-4-hydroxyphenyl acry-late) and its Cu(II) and Ni(II) complexesrdquo European PolymerJournal vol 40 no 10 pp 2313ndash2321 2004
[30] A V Nikolaev V A Logvinenco and L I Myachina ThermalAnalysis Academic Press New York NY USA 1969
[31] A Z El-Sonbati and M A Hefni ldquoPolymer complexes PartXXVImdashNovel mixed ligand poly-(5-vinyl salicylidene)-12-diaminobenzene complexesrdquo Polymer Degradation and Stabil-ity vol 43 no 1 pp 33ndash42 1994
[32] A S Aswar and N S Bhave ldquoThermal degradation studies ofsome new coordination polymersrdquo Polymer Degradation andStability vol 31 no 1 pp 115ndash124 1991
[33] T Ahamad V Kumar and N Nishat ldquoSynthesis characteri-zation and antimicrobial activity of transition metal chelatedthiourea-formaldehyde resinrdquo Polymer International vol 55no 12 pp 1398ndash1406 2006
[34] M M Patel M A Kapadia G P Patel and J D Joshi ldquoSynthe-sis characterization ion-exchange and antimicrobial study of
poly[(2-hydroxy-4-methoxybenzophenone) propylene] resinand its polychelates with lanthanides (III)rdquo Journal of AppliedPolymer Science vol 106 no 2 pp 1307ndash1317 2007
[35] M A Neelakantan S S Marriappan J Dharmaraja T Jeyaku-mar and K Muthukumaran ldquoSpectral XRD SEM and bio-logical activities of transition metal complexes of polydentateligands containing thiazole moietyrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 71 no 2 pp 628ndash635 2008
[36] G B Bagihalli S A Patil and P S Badami ldquoSynthesisphysicochemical investigation and biological studies of zinc(II)complexes with 124-triazole schiff basesrdquo Journal of the IranianChemical Society vol 6 no 2 pp 259ndash270 2009
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Inorganic ChemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Carbohydrate Chemistry
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
Physical Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom
Analytical Methods in Chemistry
Journal of
Volume 2014
Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
SpectroscopyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Medicinal ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chromatography Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Applied ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Theoretical ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Spectroscopy
Analytical ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Quantum Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Organic Chemistry International
ElectrochemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CatalystsJournal of
Bioinorganic Chemistry and Applications 3
O2N
O2N
N
2-Amino-6-nitro-benzothiazole
2-Amino-6-nitro-benzothiazole-Ethylenediamine-Formaldehyde terpolymer
[BEF terpolymer]
Ethylenediamine
DMFFormaldehyde
N
S
Sn
n
nNH2
NH NH NH
CH2
CH2 CH2 CH2 CH2
H HC
O
CH2NH2 NH2 2n+ +
150 plusmn 2∘C6h
Scheme 1 Reaction route of the BEF terpolymer ligand
60∘C
O2NBEF terpolymer ligand
BEF terpolymer metal complexes
EtOH
N
Sn
NH NH NHCH2 CH2 CH2 CH2
O2N
N
Sn
NH NH
M2
NHCH2 CH2 CH2 CH2
3 h reflux
M2+
[M = Cu(II) Ni(II) and Zn(II)]
Scheme 2 Reaction route of the BEF metal complexes
24 Elemental Analysis The elemental analysis has beencarried out using Elementar instrument model Vario ELIII Germany The percentage of elements such as carbon(C) hydrogen (H) nitrogen (N) and sulphur (S) presentin the 2-amino-6-nitro-benzothiazole-ethylenediamine-formaldehyde (BEF) terpolymer and its metal complexeswith the metal ion content was determined
25 Gel Permeation Chromatography The number average(119872119899) weight average (119872
119908) and size average (119872
119911)molecular
weights of terpolymer were measured by gel permeationchromatography (Shimadzu Japan) using tetrahydrofuran(THF) as a mobile phase and CLC polystyrene as a stationaryphase in the column
26 Spectral Analyses TheUV-Visible spectra of the terpoly-mers and its metal complexes were recorded in Shimadzu(model 1601PC) UV-Visible spectrophotometer Japan The
ESR spectra of the terpolymer and its metal complexeswere recorded in Bruker instrument model EleXsys E 500USA The FTIR spectra of the terpolymer and its metalcomplexeswere obtainedwithAvatar (model 330USA) FTIRspectrometer using KBr The 1H and 13C NMR spectra wererecorded on a Bruker 400MHz (USA) NMR spectrometerusing DMSO-d
6as a solvent
27 SEM and XRD Methods The surface analysis of theBEF terpolymer and its metal complexes was examined atdifferent magnifications by scanning electron microscopeusing Hitachi instrument model S-3000H Japan The XRDanalysis of the terpolymer and its metal complexes wasperformed using PANalytical instrument (XrsquoPert PRO TheNetherlands)
28 Thermogravimetric Analysis The thermal stability of theBEF terpolymer and its metal complexes was observed bythermogravimetric analysis using TA instruments model
4 Bioinorganic Chemistry and Applications
SDT Q600 USA at a heating rate of 20∘Cmin in a staticnitrogen atmosphere
281 Thermal Degradation Kinetics and Mechanism Sharp-Wentworth and Freeman-Carroll methods have beenemployed for the determination of kinetic and thermo-dynamic parameters such as order of reaction (119899) activationenergy (119864
119886) entropy change (Δ119878) free energy change
(Δ119865) apparent entropy (119878lowast) and frequency factor (119885)Phadnis-Deshpande method has also been used to proposethe thermal degradation mechanism for the synthesizedterpolymer and its metal complexes [20]
29 Antimicrobial Analysis by Disc Diffusion Method TheBEF terpolymer and its metal complexes were screened fortheir antimicrobial activity by disc diffusion method [21]against six bacterial strains such as Shigella sonneiEscherichiacoli Klebsiella species (NCIM 2719) Staphylococcus aureus(ATCC 25923) Bacillus subtilis (ATCC 6633) and Salmonellatyphimurium (ATCC 23564) and six fungal strains such asAspergillus flavus Aspergillus niger Penicillium species Can-dida albicans Cryptococcus neoformans and Mucor speciesAntimicrobial activity was tested by the filter paper discdiffusion technique involving the cultures of the selectedorganisms for 24 hMuellerHinton agar number 2 (HiMediaIndia) was used as the bacteriological medium and sterileyeast nitrogen base with 2 agar (Hi Media India) was usedas the fungal medium The test solutions of the terpolymerand its metal complexes were prepared in sterile dimethylsulfoxide (DMSO) solvent for the study The synthesized ter-polymer and its metal complexes were tested at different con-centrations ranging from 50 to 1000 ppm to find out the min-imum concentration of the terpolymer ligand and its metalcomplexes required for inhibiting the growth of microbes
Amoxicillin (100 120583gmL) was taken as the standard forantibacterial activity The organism was seeded into sterilenutrient agar medium by mixing one mL of inoculum with20mL sterile melted nutrient agar kept at 48ndash50∘C in a sterilepetri dish The medium was allowed to solidify first Thenthe test solutions the standard drugs and the blank wereimpregnated in whatman filter paper discs placed on thesolidified medium in the petri dish and left undisturbed for2 h at room temperatureThepetri disheswere then incubatedat 37∘C for 24 h and the zone of inhibition for the test samplesstandard and control (DMSO) was measured
Sterile yeast nitrogen base (Hi Media) with 2 agar wasinoculated by a rotating swab (soaked in standard inoculumsuspension) over the surface of the media Fluconazole(100mcgmL) was taken as the standard for antifungalactivity The test solution impregnated discs were placed onthe agar andwere incubated at 37∘C for 18 hThe zone of inhi-bition was measured by measuring the minimum dimensionof the zone of fungal growth around the filter paper disc
3 Results and Discussion
31 Physicochemical and Analytical Data The physicochem-ical and analytical data of the BEF terpolymer and its metal
complexes are given in Table 1 The BEF terpolymer is yellowin colour and itsmetal complexes are brown forCu2+ complexand yellow for Ni2+ and Zn2+ complexesThe yield of the BEFterpolymer ligand was 79 and the yield of Cu2+ Ni2+ andZn2+ complexes was 80 77 and 78 respectively Basedon the analytical data from the elemental analysis the empir-ical formula of the BEF terpolymer ligand and its metal com-plexes is found to be in good agreement with the calculatedelemental values of C H N S and M The amount of metalions present in the metal complexes indicates 1 2ML sto-ichiometry suggesting six coordination involving two coor-dinated water molecules for BEFndashCu BEFndashNi and BEFndashZncomplexes From the results the general empirical formulaof the repeating unit of the BEF terpolymer is C
11H13N5O2S
and of the metal complexes is C22H26N10O4S2Cusdot2H
2O
for BEFndashCu C22H26N10O4S2Nisdot2H
2O for BEFndashNi and
C22H26N10O4S2Znsdot2H
2O for BEFndashZn From the molar con-
ductance values the metal complexes were found to beelectrolytes
32 Molecular Weight Measurements The average molecularweight of the BEF terpolymer was determined by gel perme-ation chromatographyTheweight average (119872
119908) and number
average (119872119899)molecular weight of the terpolymer were found
to be 1941 and 1940 respectively The polydispersity index(119872119908119872119899) was found to be 10005 The average molecular
weight (119872119911) of the terpolymer was found to be 1942 The
polydispersity index (119872119911119872119908) of the terpolymer is 10005
The polydispersity index (119872119908119872119899) and (119872
119911119872119908) values for
the terpolymer indicate the narrow distribution of molecularweight in the terpolymer
33 FTIR Spectra The FTIR spectra of BEF terpolymerligand and its metal complexes are depicted in Figure 1 andthe data are presented in Table 2 The band frequencies andthe groups assigned to both terpolymer ligand and its metalcomplexes are based on the earlier literature [22 23] Theligand spectrum showed a band appearing in the range of3455ndash3297 cmminus1 is assigned to the ndashNH asymmetric andsymmetric vibrations The 268-trisubstituted benzothiazolering is confirmed by sharp and medium absorption bandsappearing between 1296 and 825 cmminus1 A strong band thatappeared at 1532 cmminus1 is due to the ndashNH bending vibrationA band that appeared at 2731 cmminus1 is assigned to the ndashCHstretching vibrations present in the aromatic ring The bandsappearing in the region of 3078ndash2936 cmminus1 are attributed tondashCH2asymmetric and symmetric vibrations present in the
terpolymer ligand The presence of ndashCH2bending vibration
in NndashCH2ndashCH2ndashN bridge in the spectrum is confirmed by
the absorption band that appeared at 1450 cmminus1In the spectra of BEF metal complexes the bands are
slightly broadened compared to the terpolymer ligand Theband that appeared at 1532 cmminus1 is assigned to ndashNH bendingvibrations in the ligand spectrum that is shifted to the lowerfrequencies (1521 to 1527 cmminus1) in the case of polymer-metalcomplexes This shift is due to the coordination of metalions through the lone pair of both nitrogen atoms present
Bioinorganic Chemistry and Applications 5
Table 1 Physicochemical and analytical data
Compound Empirical formula ofthe repeating unit Formula mass
Elemental analysis ()Λ (Ωminus1 cm2 molminus1)Found (calc)
C H N S MBEF ligand C11H13N5O2S 27936 4709 (4729) 416 (435) 2521 (2549) 1120 (1139) mdash mdashBEFndashCu C22H26N10O4S2Cusdot2H2O 65823 4071 (4092) 439 (462) 2174 (2194) 919 (927) 931 (962) 13205BEFndashNi C22H26N10O4S2Nisdot2H2O 65334 4025 (4037) 447 (479) 2129 (2146) 962 (983) 926 (945) 9837BEFndashZn C22H26N10O4S2Znsdot2H2O 66010 4023 (4052) 423 (445) 2138 (2153) 912 (929) 941 (970) 11329C carbon H hydrogen N nitrogen S sulphur and M metal ion
Table 2 FTIR data
Compound Observed frequencies (cmminus1)BEF ligand BEFndashCu BEFndashNi BEFndashZn
] NH (asym and sym) 3455minus3297 3408ndash3296 3348ndash3295 3345ndash3280] NH (bending) 1532 1527 1526 1521CH (stretching) 2731 2697 2712 2725] CH2 (asym and sym) 3078ndash2936 3093ndash2912 3098ndash2932 3087ndash2945] CH2 (bending in NndashCH2ndashCH2ndashN) 1450 1448 1449 1446268-tri substitution (benzothiazole) 1296minus825 1298ndash825 1293ndash827 1292ndash825] NrarrM mdash 432 433 433] CndashNO2 1505ndash1518 1503ndash1576 1524ndash1575 1513ndash1583] C=N 1540 1590 1586 1580] CndashSndashC 740 753 763 748
Tran
smitt
ance
()
(a)
4000 3500 3000 2500 2000 1500 1000 500
(b)
(c)
(d)
Wavenumber (cmminus1)
Figure 1 FTIR spectra of (a) BEF (b) BEFndashCu (c) BEFndashNi and (d)BEFndashZn
in the ethylenediamine moiety It is a clear evidence for theinvolvement of nitrogen atoms in the chelationThis is furthersupported by the appearance of ]NrarrM stretching vibrationat 432ndash433 cmminus1
34 Electronic and ESR Spectra and Magnetic MomentsThe electronic spectra of the BEF terpolymer and its metalcomplexes are shown in Figure 2 and the data are presentedin Table 3 The spectrum of the ligand showed two bands at
100
Abso
rban
ce
050
0400
Wavelength (nm)600200 800
(d)(c)(b)
(a) (d)((c)(b)((((
(a)aaaaa
Figure 2 Electronic spectra of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
260 and 370 nmThese observed positions for the absorptionbands have different intensitiesThe less intense band 260 nmis due to (120587 rarr 120587
lowast) allowed transition of chromophoregroups like NO
2 gtC=N and C=C which are in conjugation
with an aromatic nucleus (benzothiazole ring) and the moreintense band 370 nm may be due to (119899 rarr 120587
lowast) transition ofndashNH groupsThus 120587 rarr 120587lowast transition indicates the presence
6 Bioinorganic Chemistry and Applications
Table 3 UV-Visible ESR data and magnetic moments
Compound Transitions (cmminus1) Assignments Geometry ESR Magnetic moment (BM)119892II 119892
perp
BEF 260 nm 120587 rarr 120587lowast mdash mdash mdash mdash370 nm 119899 rarr 120587
lowast
BEFndashCu14295 1
119861119892rarr
2119864119892
Octahedral 221 211 18516465 1119861119892rarr
2119864119892
24580 Charge transfer
BEFndashNi12474 3119879
2119892(119865) larr 3119860
2119892(119865)
Octahedral mdash mdash 30514642 31198791119892(119865) larr 3119860
2119892(119865)
24370 31198791119892(119875) larr 3119860
2119892(119865)
BEFndashZn mdash mdash Octahedral mdash mdash Diamagnetic
0 1000
Inte
nsity
2000 3000 4000 5000 6000 7000G
Figure 3 ESR spectra of BEFndashCu complex
of aromatic nucleus and 119899 rarr 120587lowast transition indicates thepresence of ndashNH groups The electronic spectrum of BEFndashCu metal complex exhibited bands at 14295 16465 and24580 cmminus1 and the assignments are 1119861
119892rarr2119864119892 1119861119892
rarr2119864119892 and charge transfer spectra which lead to a distorted
octahedral geometry with the magnetic moment of 185 BMThe electronic spectrum of BEFndashNi exhibits three bands at12474 14642 and 24370 cmminus1 assigned to the spin allowedtransitions 3119879
2119892(119865) larr 3119860
2119892(119865) 3119879
1119892(119865) larr 3119860
2119892(119865) and
31198791119892(119875) larr 3
1198602119892(119865) in an octahedral environment with a
magnetic moment of 305 BMThe diamagnetic nature of theBEFndashZn is also confirmed with octahedral geometry Basedon the literature the geometry is assigned to all the metalcomplexes [24]
The ESR spectrum of BEFndashCu complex is shown inFigure 3 and its spectral data are presented in Table 3 Thespectrum provides useful information about the metal ionenvironment in the respective complexes The ESR spectrumof BEFndashCu metal complex showed that 119892
= 221 and
119892perp= 211 lead to an octahedral environment According to
Kivelson and Neimen [25] the bond between the ligand andthe metal possesses a more covalent character than ionic In
general both the parallel and the perpendicular 119892 values canbe used to calculate the 119866 value by the following equation
119866 =119892minus 2002
119892perpminus 2002
(1)
Using the above equation the 119866 value for BEFndashCu was192 which clearly indicates that the complex forms with astrong field ligand
35 Nuclear Magnetic Resonance The NMR (1H and 13C)spectra for BEF terpolymer ligand and its zinc metal complex(due to d9 and d8 configurations both NMR spectra forcopper and nickel metal complexes are complicated) wererecorded to elucidate the structure of the ligand and itscomplex
351 1H NMR Spectra The 1H NMR spectra of BEF ter-polymer ligand and its Zn2+ metal complex are shownin Figure 4 The signals obtained for the terpolymer andits metal complexes were interpreted on the basis of thedata available in the literature [22 26] The spectrum ofterpolymer showed that the signals appearing in the region of739ndash824 ppm are assigned to all the protons of the aromaticring A peak appearing at 250 is assigned to the methyleneprotons of the terpolymer ligand The terpolymer spectrumshowed a signal appearing at 472 ppm that is assigned tothe ndashNH protons of ethylenediamine moiety and the peakappearing at 865 ppm is assigned to ndashNH proton of thiazolering A weak signal appearing at 302 ppmmay be assigned toethylenic protons of an ArndashCH
2ndashNHndashCH
2moiety
The spectrum of the Zn2+ complex showed multiplet inthe range of 740ndash824 ppm is assigned to the aromatic protonsand the methylene protons appeared at 215ndash250 ppm Thesignal obtained at 508 ppm is assigned to ndashNH protons ofethylenediamine and this shift from its ligand gives a clearevidence for the complexation of the ligand with the metalions through the lone pair of nitrogen of ethylenediaminemoiety
352 13C NMR Spectra The 13C NMR spectra of the BEFterpolymer ligand and its Zn2+ metal complex are shown in
Bioinorganic Chemistry and Applications 7
(ppm)
12345678910
(a)
(ppm)1 0234567891011
(b)
Figure 4 1H-NMR spectra of (a) BEF ligand and (b) BEFndashZn
200 180 160 140 120 100 80 60 40 20 0(ppm)
(a)
200 180 160 140 120 100 80 60 40 20 0(ppm)
(b)
Figure 5 13C-NMR spectra of (a) BEF ligand and (b) BEFndashZn
O2N S
N
NH NH
M
NHCH2 CH2 CH2 CH2
n
O2NS
NNH NH NHCH2 CH2 CH2 CH2
n
H2OH2O
[M = Cu(II) Ni(II) and Zn(II)]
Figure 6 Proposed geometry of BEF metal complexes
Figure 5 The observed chemical shifts are assigned on thebasis of the literature [22 27]The spectrum of ligand showedthat the corresponding peaks at 1717 1585 1315 1219 14061167 and 1253 ppm are attributed to the aromatic carbonsof the benzothiazole ring The peak appearing at 502 ppmis assigned to the methylenic carbon of NHndashCH
2bridge in
the ligand The spectrum of Zn2+ complex showed the peaksfor aromatic ring in the same region which was appearingin its parent ligand The shifting of the methylene carbonfrom 502 to 561 ppm from its ligand clearly suggests that the
coordination takes place between the nitrogen atoms of theethylenediamine moiety
From the elemental and spectral data (FTIR UV-VisESR and NMR (1H and 13C)) the structure of the BEF ter-polymer ligand and its metal complexes has been confirmedThe proposed geometry of the BEF complexes is shown inFigure 6
36 Surface Analysis The SEM is applied to understandthe surface features of the polymeric materials The SEM
8 Bioinorganic Chemistry and Applications
(a) (b)
(c) (d)
(e)
Figure 7 SEM images of (a) and (b) BEF ligand (c) BEFndashCu (d) BEFndashNi and (e) BEFndashZn
photographs in times1000 and times2000 magnifications for BEFligand and times3000 magnifications for BEF complexes areshown in Figure 7 The white bar at the bottom of the SEMphotographs represents the scale The SEM photographs ofthe BEF terpolymer ligand show leaf like appearance Thescattered structure of the terpolymer establishes a transitionstate between the crystalline and the amorphous phases [28]
Themorphology of BEF terpolymer resin exhibits growthof crystals from polymer solutions corresponding to the
most prominent organization in polymers on a large scalewith spherulites Ideally spherulites are the aggregates ofsubmicroscopic size particles Spherulites are characterizedby secondary structural features such as faint corrugationsThe SEM photographs of polymers have an appreciableamorphous fraction with a small amount of shallow pitsThe surface of BEF metal complexes contributes to greatersegments of crystalline regions compared to their parentligand which may arise from the contraction of the voids by
Bioinorganic Chemistry and Applications 9
Inte
nsity
(au
)
0 20 40 60 802120579
(a)
Inte
nsity
(au
)
0 20 40 60 802120579
(b)
Inte
nsity
(au
)
0 20 40 60 802120579
(c)
Inte
nsity
(au
)
0 20 40 60 802120579
(d)
Figure 8 XRD patterns of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
the cooperative contribution of the ligand for complexationwith metal ions or the disappearance of the voids in therearrangement of polymer chains for complexation withmetal ions This is a further evidence for the complexationof BEF terpolymer with metal ions
37 XRD Studies X-ray diffraction (XRD) patterns of BEFand its metal complexes are shown in Figure 8 It provides adetailed comparative account of the behavior of the terpoly-mer and itsmetal complexesThepattern of BEF ligand showsthe main characteristic peak and broad shoulder In view ofthe relative half value width it may be concluded that thepolymer is partially crystalline and the broad characteristicpeak indicates the amorphous nature of the terpolymerTherefore the BEF terpolymer has transition state betweenamorphous state and crystalline state whereas its metalchelates possess crystalline nature The enhanced crystallinebehavior of the BEF complexes may be due to the insertion ofmetal ions with their parent ligand [29]
38 Thermal Stability Thermal stability of the BEF terpoly-mer and its metal complexes was analyzed by thermogravi-metric analysis (TGA) The thermograms of the terpolymer
and its metal complexes are shown in Figure 9 and their per-centages of weight loss at various temperatures are presentedin Table 4
381Thermal Stability of BEF Terpolymer From the thermo-gram of BEF terpolymer there were three stages of degra-dation (200ndash320∘C 320ndash580∘C and 580ndash835∘C) observedThe first stage of degradation was observed between 200∘Cand 320∘C (found 5883 calc 5794) which reveals thedegradation of the benzothiazole ring The second stageof degradation begins at 320∘C and ends at 580∘C (found1003 calc 0931) which may be due to the eliminationof cross-linkages The third and final stage of degradation isobserved above 580∘C and continued up to 825∘C (found2506 calc 2473) which can be attributed to the weightloss of aliphatic group (ethylenediamine moiety) from theBEF terpolymer
382 Thermal Stability of BEF Metal Complexes In generalthe water of hydration may be considered as either crystalwater molecules or coordination water molecules Accordingto Nikolaev et al [30] water eliminated below 150∘C can beconsidered as crystal or lattice water and water eliminated
10 Bioinorganic Chemistry and Applications
Table 4 TGA data for thermal stability
Compound Percentage of weight loss at various temperatures11987950
lowast (∘C) 119879maxlowastlowast (∘C)
100 200 300 400 500 600 700 800 (∘C)BEF ligand 0153 0365 4414 6236 6718 7140 8224 9442 310 825BEFminusCu 0194 1432 3180 4301 4996 5549 6686 8122 500 860BEFminusNi 0893 1660 3735 4935 6460 8767 mdash mdash 405 650BEFminusZn 1464 2262 3833 4616 5726 6492 7614 9129 425 830lowastTemperature of 50 weight loss lowastlowastmaximum decomposition temperature
80
60
40
20
0
0
(a)(b)
(c)(d)
200 400 600 800 1000
100
Wei
ght (
)
Temperature (∘C)
Figure 9 TGA of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d)BEFndashZn
above 150∘C may be due to its coordination to the metalatom present in chelates In the present study in the case ofBEFndashCu2+ Ni2+ and Zn2+ complexes the removal of waterfrom the complex was completed within 150∘C These watermolecules are probably crystal or lattice water moleculesTheremoval of water molecules observed in the range of 150ndash200∘C (found 559ndash608 calc 545ndash551) of all the metalchelates is due to the elimination of two coordinated watermolecules These observations further confirm the distortedoctahedral geometry of BEF metal complexes
The thermogravimetric curves of all the BEF metalchelates showed two degradation steps after loss of watermolecules whichmay indicate that the first step (200ndash600∘C)is faster than the second step (600ndash860∘C) This may bedue to the fact that the noncoordinated part of the liganddecomposes firstwhile the coordinated part decomposes laterand finally it may form the representative metal oxides Theweight of the residues confirms fairly well that ofmetal oxides(found 1247ndash1362 calc 1143ndash1232)
The thermal degradation data of the BEF terpolymerand its metal complexes reveal that the polymeric complexesshow better stability than the BEF terpolymer due to thecoordination of metal ions The order of thermal stability ofthe BEF polymer and its complexes is BEFndashCu2+ gt BEFndashZn2+ gt BEF ligand gt BEFndashNi2+ The greater stability of themetal complexes may be due to the coordination and theenhanced cross linking nature with crowd effect of the metal
complexes [31] In the case of Ni2+ complex the degradationoccurred exceptionally at low temperature compared to theirligand which may be due to the oxidation of polymer by thecatalytic action of the metal ion [32]
383 Thermal Kinetics
(1) Sharp-Wentworth and Freeman-Carroll Method Ther-mal kinetic analysis was performed using Sharp-Wentworthmethod and Freeman-Carroll methods The activationenergy (119864
119886) and order of reaction (119899) plots for BEF terpoly-
mer ligand and its metal complexes by Sharp-Wentworthand Freeman-Carroll methods are shown in Figures 10 11and 12 The expressions used to calculate the kinetic andthermodynamic parameters are presented as follows
(i) Entropy change (Δ119878)
Intercept = log 119870119877
ℎΦ119864119886
+Δ119878
2303119877 (2)
where 119870 = 13806 times 10minus16 ergdegmole 119877 =
1987 caldegmole (8314 JKMol) ℎ = 6625 times
10minus27 erg sec Φ = 0166 Δ119878 = change in entropyand 119864
119886= activation energy from graph
(ii) Free energy change (Δ119865)
Δ119865 = Δ119867 minus 119879Δ119878 (3)
where Δ119867 = enthalpy change = activation energy 119879 =temperature in119870 and Δ119878 = result from (2)
(iii) Frequency factor (119885)
11986123
=log119885119864
119886
119877Φ (4)
11986123
= log 3 + log [1 minus 3radic1 minus 120572] minus log119901 (119909) (5)
where 119885 is the frequency factor 119861 is calculatedfrom (5) log119901(119909) is calculated from Doylersquos tablecorresponding to activation energy and 120572 is degreeof transformation (120572 = 119908119882
119888)
(iv) Apparent entropy (119878lowast)
119878lowast= 2303 log 119885ℎ
119877119879lowast (6)
where119885 is calculated from (4) and 119879lowast is half decom-position temperature
Bioinorganic Chemistry and Applications 11
1000T (Kminus1)
Intercept = minus535
minus45
minus50
minus55
minus60
minus65
minus70
minus75
minus80
10 15 20 25 30
Ea = 952
log[
(dC
dT
)(1
minusC
)]
(a)
minus64
minus62
minus60
minus58
minus56
minus54
minus52
1000T (Kminus1)10 15 20 25 30
Intercept = minus527
Ea = 1297
log[
(dC
dT
)(1
minusC
)]
(b)
minus64
minus62
minus50
minus52
minus54
minus56
minus58
minus60
1000T (Kminus1)10 15 20 25 30
Intercept = minus513
Ea = 693
log[
(dC
dT
)(1
minusC
)]
(c)
minus50
minus51
minus52
minus53
minus54
minus55
minus56
minus57
minus58
minus59
1000T (Kminus1)10 15 20 25 30
Intercept = minus538
Ea = 1108
log[
(dC
dT
)(1
minusC
)]
(d)
Figure 10 Sharp-Wentworth plots of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Table 5 Kinetic and thermodynamic parameters data
CompoundActivation energy
(119864119886kJmolminus1) Entropy change
(Δ119878J)Free energy
change (Δ119865kJ)Frequency
factor (119885sminus1)Apparent
entropy (119878lowastJ)Order of
reaction (119899)lowastSW lowastlowastFC
BEF ligand 952 1039 minus15811 5940 1310 minus2295 090BEFminusCu 1297 1367 minus15425 9079 1205 minus2331 104BEFminusNi 693 460 minus16290 7057 1537 minus2294 093BEFminusZn 1108 1213 minus16001 8013 1243 minus2318 102lowastSW Sharp-Wentworth lowastlowastFC Freeman-Carroll
Further from the knowledge of activation energy cal-culated by Freeman-Carroll method it is possible to eval-uate the values of various thermodynamic parameters Theorder of reaction (119899) and activation energy (119864
119886) and the
thermodynamic parameters such as frequency factor (119885)entropy change (Δ119878) free energy change (Δ119865) and apparententropy (119878lowast) are presented inTable 5The119864
119886values calculated
by SW and FC methods are in good agreement with eachother The order of activation energies for BEF ligand andits Cu2+ Ni2+ and Zn2+ complexes is parallel to the orderof their thermal stability [32] The values of thermodynamic
parameters were comparable indicating a common modeof decomposition reaction The abnormal low values offrequency factor (119885) indicate that the decomposition reactionof BEF terpolymer and its metal complexes can be depictedas a slow reaction The order of reactions (119899) of BEF ligandand its metal complexes is found to be 090 104 093 and102 respectively Hence the BEF terpolymer and its mealcomplexes may be following nearly a first order kinetics
(2) Phadnis-Deshpande Method The activation energiescalculated for BEF ligand and its metal complexes using
12 Bioinorganic Chemistry and Applications
minus00012minus00010minus00008minus00006minus00004minus00002minus00000
26242220181614121008060402
log(dWdt)
(1T)
n = 090
logW
r
logWr
(a)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
20
19
18
17
16
15
14
13
12
11
10
log(dWdt)
(1T)
n = 104
logWr
logW
r
(b)
15
16
17
18
19
14
13
12
11
10
09
log(dWdt)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
(1T)
n = 093logW
r
logWr
(c)
15
16
17
18
14
13
12
11
10
log(dWdt)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
(1T)
n = 102
logW
r
logWr
(d)
Figure 11 Freeman-Carroll plots (119899) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Phadnis-Deshpande method are presented in Table 6 Fromthe 119864
119886values it is possible to propose the degradation
reactionmechanism using PDmethod Further the 119864119886values
calculated by PD method are in good agreement with FCand SW methods Based on the closest 119864
119886values calculated
by PD SW and FC methods the Power law mechanismsuits very well for the BEF ligand and BEFndashCu and BEFndashZn metal complexes However BEFndashNi complex follows theBrounshtein-Ginstling 3-dimensional diffusion mechanism
39 Biological Studies
391 Antibacterial Activity To determine the antibacterialactivity of the BEF terpolymer and its Cu2+ Ni2+ andZn2+ complexes the disc diffusion method was used withamoxicillin as the standard antibiotic The prepared com-pounds were tested against Shigella sonnei Escherichia coliKlebsiella species Staphylococcus aureus Bacillus subtilis andSalmonella typhimuriummicroorganisms
Table 7 contains the screening results corresponding tothe polymeric ligand and its metal complexes with fairinhibition of growth against the tested organisms Shigella
sonnei is a nonmotile non-spore-forming and facultativeanaerobic gram-negative bacterium Shigella bacteria multi-ply within colonic epithelial cells and cause mucosal ulcer-ation inflammation bleeding high fever malaise diarrheaand tenesmus The ligand and its metal complexes showeda reasonable activity against the S sonnei species E coliis an aerobic gram-negative and rod shaped bacteriumInfection of E coli can lead to bloody diarrhea and kidneyfailureThe polymeric ligand and its complexes hold amodestactivity against the E coli Klebsiella is a genus of nonmotileand gram-negative bacteria that infects sites such as nasalpassages liver lung urinary tract bloodstream eye boneand joints It causes a wide range of disease states notablypneumonia septicemia soft tissue infections biliary tractinfection infection of the upper and lower respiratory tractand liver abscess The BEF ligand and its metal complexesshowed a reasonable result against the growth of KlebsiellaStaphylococcus aureus a gram-positive and spherical bac-terium leads to life-threatening diseases like pneumoniaosteomyelitis endocarditis and toxic shock syndrome Toxicshock syndrome is characterized by the sudden onset of highfever vomiting diarrhea and muscle aches followed by lowblood pressure (hypotension) which can lead to shock and
Bioinorganic Chemistry and Applications 13
log[g
(120572)T3]
minus95
minus90
minus85
minus80
minus75
10 15 20 25 30
Intercept = minus825
Ea = 1039
1000T (Kminus1)
(a)
log[g
(120572)T3]
minus78
minus80
minus82
minus84
minus86
minus88
minus90
minus92
minus94
minus96
minus76
Intercept = minus805
Ea = 1367
10 15 20 25 30
1000T (Kminus1)
(b)
log[g
(120572)T3]
minus77
minus78
minus79
minus80
minus81
minus82
minus83
minus84
minus85
minus86
minus87
minus88minus89
Intercept = minus849
Ea = 460
10 15 20 25 30
1000T (Kminus1)
(c)
minus78
minus80
minus82
minus84
minus86
minus7610 15 20 25 30
1000T (Kminus1)
log[g
(120572)T3]
Intercept = minus835
Ea = 1213
(d)
Figure 12 Freeman-Carroll plots (119864119886) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Table 6 Activation energies calculated by Phadnis-Deshpande method
Reaction mechanism model Energy of activation (119864119886) (kJmol)
BEF ligand BEFminusCu BEFminusNi BEFminusZnPower law 60932 62642 59691 54312Power law 121864 125284 119382 108625Phase boundary (contracting sphere) 16497 16816 16174 15009Phase boundary (contracting cylinder) 25894 26436 25383 23466Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 12135 13830 11756 07447
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 08090 09220 07837 04964
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 06067 06915 05878 03723
Valensi 2-dimensional diffusion 168354 171926 165034 152695Jander 3-dimensional diffusion 32995 33632 32349 30018Brounshtein-Ginstling 3-dimensional diffusion 56520 55015 55669 57981The values indicated in bold are closest to the 119864119886 value estimated by FC and SWmethods
14 Bioinorganic Chemistry and Applications
Table 7 Antibacterial activity of BEF ligand and its complexes
Compound Inhibition zone (mm)S sonnei E coli Klebsiella sp S aureus B subtilis S typhi
BEF ligand 15 13 13 14 15 12BEFndashCu 21 17 17 18 18 18BEFndashNi 18 15 18 17 20 15BEFndashZn 16 15 15 16 17 15Standard 26 28 26 25 27 28Control mdash mdash mdash mdash mdash mdashStandard amoxicillin control DMSO
Table 8 Antifungal activity of BEF ligand and its complexes
Compound Inhibition zone (mm)Aspergillus flavus Aspergillus niger Penicillium species Candida albicans Cryptococcus neoformans Mucorspecies
BEF ligand 14 12 12 13 11 12BEFndashCu 20 18 19 18 15 19BEFndashNi 17 14 17 15 13 13BEFndashZn 15 15 18 17 14 16Standard 20 21 19 21 18 22Control mdash mdash mdash mdash mdash mdashStandard fluconazole control DMSO
death There may be a rash resembling sunburn with peelingof skin The ligand and its complexes showed a humbleactivity against the growth of S aureus Bacillus subtilis arerod-shaped and nonpathogenic gram-positive bacteria TheBEF ligand and complexes showed superb activity againstthe growth of this bacterium Salmonella typhimurium is apathogenic gram-negative bacteria predominately found inthe intestinal lumen When the bacterial cells enter epithelialcells lining the intestine they cause host cell ruffling whichtemporarily damages the microvilli on the surface of the cellThis causes a rush of white blood cells into the mucosa andleads to diarrheaThe ligand and its metal complexes showeda moderate activity against the growth of the typhi species
A comparative account on the effect of antibacterialactivity against the chosen microbes indicates that the ligandand its three metal chelates show reasonable activity againstShigella sonnei (15 21 18 and 16mm) and Bacillus subtilis (1518 20 and 17mm) while the growth of other organisms ismoderately inhibited by the BEF ligand and its Cu2+ Ni2+and Zn2+ chelates The highest antibacterial action (21mm)has been observed for BEFndashCu2+ complex against Shigellasonnei
392 Antifungal Activity The antifungal activity of the BEFligand and its metal complexes has also given interestingresults and the growth inhibitions against the chosen fungalstrains are tabulated in Table 8 All the complexes and theirligand have an excellent activity against Aspergillus flavusa mold type fungal strain which may invade arteries of thelung or brain to cause infections and also produce a toxinAspergillus niger is one of the most common causes for
otomycosis The chelates and the ligand are found to havea reasonable activity for A niger Penicillium species causesinfection in humans and the resulting disease is known gener-ically as penicilliosis The ligand and the metal complexeshave wonderful activity against this species Further BEFndashCucomplex has a superior activity compared to the rest of othercomplexes Candida albicans is a diploid fungus and a causalagent of opportunistic oral and genital infections in humansand also emerged as an important cause of morbidity andmortality in immunocompromised patients The BEF ligandand its chelates possess a modest activity against C albicansover and above the standard Cryptococcus neoformans is anencapsulated yeast-like fungus that can live in both plantsand animals and cause lung infection The terpolymer ligandand its chelates have a fair activity against this fungal strainThe chelate compounds and the ligand havemoderate activityagainst Mucor species a filamentous fungus which causesseptic arthritis renal infections and pulmonary infections
From the antimicrobial results themetal complexes showhigher activity than their ligand which may be stronglydependent on the central metal ions and coordination num-bers metal chelates The higher activity due to the metal ionsshared with the donor atoms (N and S) of the thiazole ring ispresent in the ligand and the 120587-electron delocalization overthe chelate ring This effect increases the lipophilic characterof the metal ion which favors the permeation through thelipoid layers of the bacterial and fungal membranes [33 34]It is perceived that the factors such as solubility conductivitydipole moment and cell permeability may also contributeto the increased activity of the complexes [35 36] Fromthe results of the studies at 500 ppm concentration thecompounds establish better antimicrobial activity Hence it
Bioinorganic Chemistry and Applications 15
is an interesting result that a very low concentration of thecompound namely 500 ppm is enough to bring out aneffective inhibition against the chosen microbes
4 Conclusion
The synthesized 2-amino-6-nitro-benzothiazole-ethylene-diamine-formaldehyde terpolymer has acted as a ligandsuccessfully to form metal complexes The synthesized com-pounds were well characterized by various spectral andphysical analyses The morphological features suggest thatthe complexes are slightly more crystalline in nature thantheir parent ligandThe antibacterial and antifungal activitiesreveal that the terpolymer and its metal complexes can beactive against the selected bacterial and fungal strains Nearlyall of the compoundsmay suit well for drug delivery field afterchecking for their toxicology behaviour in thorough mannerThermal studies are also helpful to realize the standing capac-ity of the compounds which survive as antimicrobial coatingmaterials in various environmental conditions Because ofthe proven high stability nature and microbial preventioncapacity the BEF terpolymer and its Cu2+ Ni2+ and Zn2+complexes hold inadequate applications in biological fieldThe thermal stability of the terpolymer and its metal com-plexes was found greater From the thermodynamic andkinetic studies the abnormal low values of frequency factor(119885) indicate that the thermal decomposition reaction of BEFterpolymer and its metal complexes can be depicted as a slowreaction The BEF terpolymer and its metal complexes maybe following nearly a first order kinetics
Conflict of Interests
The authors certify that there is no conflict of interests withany financial organization regarding thematerial discussed inthe paper
Acknowledgments
The authors thank the Management and Principal ofOxford Engineering College Tiruchirappalli CoimbatoreInstitute of Technology Coimbatore Jamal Mohamed Col-lege (Autonomous) Tiruchirappalli Tamil Nadu and DrD Jeyakumar Scientist Central Electrochemical ResearchInstitute (CECRI-CSIR) Karaikudi Tamil Nadu for theirsupport and encouragement
References
[1] C U Pittman K S Ramachandran Jr and K R LowyerldquoSynthesis of fungicidal monomers polymers and latticesrdquoJournal of Coating Technology vol 54 pp 27ndash40 1982
[2] M N Patel J R Patel and D H Sutaria ldquoNovel co-ordinationpolychelatesrdquo Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry vol 24 no 8 pp 1297ndash1309 1994
[3] V V Ukey and H D Juneja ldquoSynthetic and spectroscopicstudies of chelate polymers involving azelaoyl bis-N-phenylhydroxamic acid with transition metal ionsrdquo Journal of AppliedPolymer Science vol 99 no 1 pp 273ndash278 2006
[4] S K-H Thiele and D R Wilson ldquoAlternate transition metalcomplex based diene polymerizationrdquo Polymer Reviews vol 43no 4 pp 581ndash628 2003
[5] N Nishat S Ahmad and T Ahamad ldquoSynthesis and character-ization of antibacterial polychelates of urea-formaldehyde resinwith Cr(III) Mn(II) Fe(III) Co(II) Ni(II) Cu(II) and Zn(II)metal ionsrdquo Journal of Applied Polymer Science vol 100 no 2pp 928ndash936 2006
[6] E Brzezinska G Koska and K Walczynski ldquoApplicationof thin-layer chromatographic data in quantitative structure-activity relationship assay of thiazole and benzothiazole deriva-tives with Hmdashantihistamine activityrdquo Journal of Chromatogra-phy A vol 1007 pp 145ndash155 2003
[7] M A R Ahamed and A R Burkanudeen ldquoMetal complexesof a novel terpolymer ligand synthesis spectral morphologythermal degradation kinetics and antimicrobial screeningrdquoJournal of Inorganic andOrganometallic Polymers andMaterialsvol 22 no 5 pp 1046ndash1061 2012
[8] B S Holla K V Malini V S Rao B K Sarojini and N SKumari ldquoSynthesis of some new 24-disubstituted thiazoles aspossible antibacterial and anti-inflammatory agentsrdquo EuropeanJournal of Medicinal Chemistry vol 38 no 3 pp 313ndash318 2003
[9] O I El-Sabbagh M M Baraka S M Ibrahim et al ldquoSynthesisand antiviral activity of new pyrazole and thiazole derivativesrdquoEuropean Journal of Medicinal Chemistry vol 44 no 9 pp3746ndash3753 2009
[10] A Andreani M Granaiola A Leoni A Locatelli R Morigiand M Rambaldi ldquoSynthesis and antitubercular activity ofimidazo[21-b]thiazolesrdquo European Journal of Medicinal Chem-istry vol 36 no 9 pp 743ndash746 2001
[11] E Yousif Y Farina K Kasar A Graisa and K Ayid ldquoCom-plexes of 2-thioacetic acid benzothiazole with somemetal ionsrdquoAmerican Journal of Applied Sciences vol 6 no 4 pp 582ndash5852009
[12] B P Mallikarjuna B S Sastry G V Suresh Kumar Y Rajen-draprasad S M Chandrashekar and K Sathisha ldquoSynthesis ofnew 4-isopropylthiazole hydrazide analogs and some derivedclubbed triazole oxadiazole ring systemsmdasha novel class ofpotential antibacterial antifungal and antitubercular agentsrdquoEuropean Journal of Medicinal Chemistry vol 44 pp 4739ndash4746 2009
[13] T Ahamad V Kumar and N Nishat ldquoNew class of anti-microbial agents synthesis characterization and anti-microbial activities of metal chelated polyureardquo Journal ofBiomedical Materials Research A vol 88 no 2 pp 288ndash2942009
[14] M V Patel J N Patel M B Dolia and R M Patel ldquoPolyether-ketones synthesis characterization and antimicrobial activityrdquoInternational Journal of Polymeric Materials and PolymericBiomaterials vol 54 no 11 pp 1059ndash1071 2005
[15] K R Alagawadi and S G Alegaon ldquoSynthesis characteriza-tion and antimicrobial activity evaluation of new 24-Thiazoli-dinediones bearing imidazo[21-b][134]thiadiazole moietyrdquoArabian Journal of Chemistry vol 4 no 4 pp 465ndash472 2011
[16] M Ashok B S Holla and N S Kumari ldquoConvenientone pot synthesis of some novel derivatives of thiazolo[23-b]dihydropyrimidinone possessing 4-methylthiophenyl moietyand evaluation of their antibacterial and antifungal activitiesrdquoEuropean Journal ofMedicinal Chemistry vol 42 no 3 pp 380ndash385 2007
16 Bioinorganic Chemistry and Applications
[17] T Ahamad V Kumar S Parveen and N Nishat ldquoIn vitroantibacterial and antifungal assay of poly-(ethylene oxamide-NN1015840-diacetate) and its polymer-metal complexesrdquo AppliedOrganometallic Chemistry vol 21 no 12 pp 1013ndash1021 2007
[18] R S Azarudeen M A R Ahamed and A R BurkanudeenldquoBiological and thermal investigations of polychelates derivedfrom a novel terpolymer ligandrdquo Journal of Polymer Researchvol 18 no 6 pp 1331ndash1341 2011
[19] R S Azarudeen and A R Burkanudeen ldquoSynthesis spectralmorphology thermal degradation kinetics and antibacterialstudies of terpolymermetal complexesrdquo Journal of Inorganic andOrganometallic Polymers and Materials vol 22 no 4 pp 791ndash806 2012
[20] R S Azarudeen and A R Burkanudeen ldquoStudies of newoligomer-metal complexes and their antibacterial activitiesrdquoPolymer International vol 62 no 3 pp 362ndash374 2013
[21] G S Devi A K Muthu D S Kumar S Rekha R Indhumathiand R Nandhini ldquoStudies on the antibacterial and antifungalactivities of the ethanolic extracts of Luffa cylindrica (Linn)fruitrdquo International Journal of Drug Development and Researchvol 1 pp 105ndash109 2013
[22] R M Silverstein and G C Bassler Spectrometric IdentificationofOrganic Compounds JohnWileyamp SonsNewYorkNYUSA2nd edition 1967
[23] Y-G Zhao H-Y Shen S-D Pan and M-Q Hu ldquoSyn-thesis characterization and properties of ethylenediamine-functionalized Fe
3O4magnetic polymers for removal of Cr(VI)
in wastewaterrdquo Journal of Hazardous Materials vol 182 no 1-3pp 295ndash302 2010
[24] Y R Sharma Elementary Organic Absorption Spectroscopy SChand amp Co Ltd New Delhi India 1980
[25] D Kivelson and R Neiman ldquoESR line shapes in glasses ofcopper complexesrdquoThe Journal of Chemical Physics vol 35 no1 pp 149ndash155 1961
[26] E Pretsch P Buhlmann and C Afflolter Structure Determi-nation of Organic Compounds Springer New York NY USA2000
[27] J L White Modern Magnetic Resonance Kluwer AcademicPress London UK 2006
[28] M M Patel M A Kapadia and J D Joshi ldquoThermal andcatalytic aspects of Ln(III) polymer-metal complexesrdquo PolymerInternational vol 58 no 7 pp 728ndash737 2009
[29] S Nanjundan C S J Selvamalar and R Jayakumar ldquoSynthesisand characterization of poly(3-acetyl-4-hydroxyphenyl acry-late) and its Cu(II) and Ni(II) complexesrdquo European PolymerJournal vol 40 no 10 pp 2313ndash2321 2004
[30] A V Nikolaev V A Logvinenco and L I Myachina ThermalAnalysis Academic Press New York NY USA 1969
[31] A Z El-Sonbati and M A Hefni ldquoPolymer complexes PartXXVImdashNovel mixed ligand poly-(5-vinyl salicylidene)-12-diaminobenzene complexesrdquo Polymer Degradation and Stabil-ity vol 43 no 1 pp 33ndash42 1994
[32] A S Aswar and N S Bhave ldquoThermal degradation studies ofsome new coordination polymersrdquo Polymer Degradation andStability vol 31 no 1 pp 115ndash124 1991
[33] T Ahamad V Kumar and N Nishat ldquoSynthesis characteri-zation and antimicrobial activity of transition metal chelatedthiourea-formaldehyde resinrdquo Polymer International vol 55no 12 pp 1398ndash1406 2006
[34] M M Patel M A Kapadia G P Patel and J D Joshi ldquoSynthe-sis characterization ion-exchange and antimicrobial study of
poly[(2-hydroxy-4-methoxybenzophenone) propylene] resinand its polychelates with lanthanides (III)rdquo Journal of AppliedPolymer Science vol 106 no 2 pp 1307ndash1317 2007
[35] M A Neelakantan S S Marriappan J Dharmaraja T Jeyaku-mar and K Muthukumaran ldquoSpectral XRD SEM and bio-logical activities of transition metal complexes of polydentateligands containing thiazole moietyrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 71 no 2 pp 628ndash635 2008
[36] G B Bagihalli S A Patil and P S Badami ldquoSynthesisphysicochemical investigation and biological studies of zinc(II)complexes with 124-triazole schiff basesrdquo Journal of the IranianChemical Society vol 6 no 2 pp 259ndash270 2009
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Inorganic ChemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Carbohydrate Chemistry
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
Physical Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom
Analytical Methods in Chemistry
Journal of
Volume 2014
Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
SpectroscopyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Medicinal ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chromatography Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Applied ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Theoretical ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Spectroscopy
Analytical ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Quantum Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Organic Chemistry International
ElectrochemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CatalystsJournal of
4 Bioinorganic Chemistry and Applications
SDT Q600 USA at a heating rate of 20∘Cmin in a staticnitrogen atmosphere
281 Thermal Degradation Kinetics and Mechanism Sharp-Wentworth and Freeman-Carroll methods have beenemployed for the determination of kinetic and thermo-dynamic parameters such as order of reaction (119899) activationenergy (119864
119886) entropy change (Δ119878) free energy change
(Δ119865) apparent entropy (119878lowast) and frequency factor (119885)Phadnis-Deshpande method has also been used to proposethe thermal degradation mechanism for the synthesizedterpolymer and its metal complexes [20]
29 Antimicrobial Analysis by Disc Diffusion Method TheBEF terpolymer and its metal complexes were screened fortheir antimicrobial activity by disc diffusion method [21]against six bacterial strains such as Shigella sonneiEscherichiacoli Klebsiella species (NCIM 2719) Staphylococcus aureus(ATCC 25923) Bacillus subtilis (ATCC 6633) and Salmonellatyphimurium (ATCC 23564) and six fungal strains such asAspergillus flavus Aspergillus niger Penicillium species Can-dida albicans Cryptococcus neoformans and Mucor speciesAntimicrobial activity was tested by the filter paper discdiffusion technique involving the cultures of the selectedorganisms for 24 hMuellerHinton agar number 2 (HiMediaIndia) was used as the bacteriological medium and sterileyeast nitrogen base with 2 agar (Hi Media India) was usedas the fungal medium The test solutions of the terpolymerand its metal complexes were prepared in sterile dimethylsulfoxide (DMSO) solvent for the study The synthesized ter-polymer and its metal complexes were tested at different con-centrations ranging from 50 to 1000 ppm to find out the min-imum concentration of the terpolymer ligand and its metalcomplexes required for inhibiting the growth of microbes
Amoxicillin (100 120583gmL) was taken as the standard forantibacterial activity The organism was seeded into sterilenutrient agar medium by mixing one mL of inoculum with20mL sterile melted nutrient agar kept at 48ndash50∘C in a sterilepetri dish The medium was allowed to solidify first Thenthe test solutions the standard drugs and the blank wereimpregnated in whatman filter paper discs placed on thesolidified medium in the petri dish and left undisturbed for2 h at room temperatureThepetri disheswere then incubatedat 37∘C for 24 h and the zone of inhibition for the test samplesstandard and control (DMSO) was measured
Sterile yeast nitrogen base (Hi Media) with 2 agar wasinoculated by a rotating swab (soaked in standard inoculumsuspension) over the surface of the media Fluconazole(100mcgmL) was taken as the standard for antifungalactivity The test solution impregnated discs were placed onthe agar andwere incubated at 37∘C for 18 hThe zone of inhi-bition was measured by measuring the minimum dimensionof the zone of fungal growth around the filter paper disc
3 Results and Discussion
31 Physicochemical and Analytical Data The physicochem-ical and analytical data of the BEF terpolymer and its metal
complexes are given in Table 1 The BEF terpolymer is yellowin colour and itsmetal complexes are brown forCu2+ complexand yellow for Ni2+ and Zn2+ complexesThe yield of the BEFterpolymer ligand was 79 and the yield of Cu2+ Ni2+ andZn2+ complexes was 80 77 and 78 respectively Basedon the analytical data from the elemental analysis the empir-ical formula of the BEF terpolymer ligand and its metal com-plexes is found to be in good agreement with the calculatedelemental values of C H N S and M The amount of metalions present in the metal complexes indicates 1 2ML sto-ichiometry suggesting six coordination involving two coor-dinated water molecules for BEFndashCu BEFndashNi and BEFndashZncomplexes From the results the general empirical formulaof the repeating unit of the BEF terpolymer is C
11H13N5O2S
and of the metal complexes is C22H26N10O4S2Cusdot2H
2O
for BEFndashCu C22H26N10O4S2Nisdot2H
2O for BEFndashNi and
C22H26N10O4S2Znsdot2H
2O for BEFndashZn From the molar con-
ductance values the metal complexes were found to beelectrolytes
32 Molecular Weight Measurements The average molecularweight of the BEF terpolymer was determined by gel perme-ation chromatographyTheweight average (119872
119908) and number
average (119872119899)molecular weight of the terpolymer were found
to be 1941 and 1940 respectively The polydispersity index(119872119908119872119899) was found to be 10005 The average molecular
weight (119872119911) of the terpolymer was found to be 1942 The
polydispersity index (119872119911119872119908) of the terpolymer is 10005
The polydispersity index (119872119908119872119899) and (119872
119911119872119908) values for
the terpolymer indicate the narrow distribution of molecularweight in the terpolymer
33 FTIR Spectra The FTIR spectra of BEF terpolymerligand and its metal complexes are depicted in Figure 1 andthe data are presented in Table 2 The band frequencies andthe groups assigned to both terpolymer ligand and its metalcomplexes are based on the earlier literature [22 23] Theligand spectrum showed a band appearing in the range of3455ndash3297 cmminus1 is assigned to the ndashNH asymmetric andsymmetric vibrations The 268-trisubstituted benzothiazolering is confirmed by sharp and medium absorption bandsappearing between 1296 and 825 cmminus1 A strong band thatappeared at 1532 cmminus1 is due to the ndashNH bending vibrationA band that appeared at 2731 cmminus1 is assigned to the ndashCHstretching vibrations present in the aromatic ring The bandsappearing in the region of 3078ndash2936 cmminus1 are attributed tondashCH2asymmetric and symmetric vibrations present in the
terpolymer ligand The presence of ndashCH2bending vibration
in NndashCH2ndashCH2ndashN bridge in the spectrum is confirmed by
the absorption band that appeared at 1450 cmminus1In the spectra of BEF metal complexes the bands are
slightly broadened compared to the terpolymer ligand Theband that appeared at 1532 cmminus1 is assigned to ndashNH bendingvibrations in the ligand spectrum that is shifted to the lowerfrequencies (1521 to 1527 cmminus1) in the case of polymer-metalcomplexes This shift is due to the coordination of metalions through the lone pair of both nitrogen atoms present
Bioinorganic Chemistry and Applications 5
Table 1 Physicochemical and analytical data
Compound Empirical formula ofthe repeating unit Formula mass
Elemental analysis ()Λ (Ωminus1 cm2 molminus1)Found (calc)
C H N S MBEF ligand C11H13N5O2S 27936 4709 (4729) 416 (435) 2521 (2549) 1120 (1139) mdash mdashBEFndashCu C22H26N10O4S2Cusdot2H2O 65823 4071 (4092) 439 (462) 2174 (2194) 919 (927) 931 (962) 13205BEFndashNi C22H26N10O4S2Nisdot2H2O 65334 4025 (4037) 447 (479) 2129 (2146) 962 (983) 926 (945) 9837BEFndashZn C22H26N10O4S2Znsdot2H2O 66010 4023 (4052) 423 (445) 2138 (2153) 912 (929) 941 (970) 11329C carbon H hydrogen N nitrogen S sulphur and M metal ion
Table 2 FTIR data
Compound Observed frequencies (cmminus1)BEF ligand BEFndashCu BEFndashNi BEFndashZn
] NH (asym and sym) 3455minus3297 3408ndash3296 3348ndash3295 3345ndash3280] NH (bending) 1532 1527 1526 1521CH (stretching) 2731 2697 2712 2725] CH2 (asym and sym) 3078ndash2936 3093ndash2912 3098ndash2932 3087ndash2945] CH2 (bending in NndashCH2ndashCH2ndashN) 1450 1448 1449 1446268-tri substitution (benzothiazole) 1296minus825 1298ndash825 1293ndash827 1292ndash825] NrarrM mdash 432 433 433] CndashNO2 1505ndash1518 1503ndash1576 1524ndash1575 1513ndash1583] C=N 1540 1590 1586 1580] CndashSndashC 740 753 763 748
Tran
smitt
ance
()
(a)
4000 3500 3000 2500 2000 1500 1000 500
(b)
(c)
(d)
Wavenumber (cmminus1)
Figure 1 FTIR spectra of (a) BEF (b) BEFndashCu (c) BEFndashNi and (d)BEFndashZn
in the ethylenediamine moiety It is a clear evidence for theinvolvement of nitrogen atoms in the chelationThis is furthersupported by the appearance of ]NrarrM stretching vibrationat 432ndash433 cmminus1
34 Electronic and ESR Spectra and Magnetic MomentsThe electronic spectra of the BEF terpolymer and its metalcomplexes are shown in Figure 2 and the data are presentedin Table 3 The spectrum of the ligand showed two bands at
100
Abso
rban
ce
050
0400
Wavelength (nm)600200 800
(d)(c)(b)
(a) (d)((c)(b)((((
(a)aaaaa
Figure 2 Electronic spectra of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
260 and 370 nmThese observed positions for the absorptionbands have different intensitiesThe less intense band 260 nmis due to (120587 rarr 120587
lowast) allowed transition of chromophoregroups like NO
2 gtC=N and C=C which are in conjugation
with an aromatic nucleus (benzothiazole ring) and the moreintense band 370 nm may be due to (119899 rarr 120587
lowast) transition ofndashNH groupsThus 120587 rarr 120587lowast transition indicates the presence
6 Bioinorganic Chemistry and Applications
Table 3 UV-Visible ESR data and magnetic moments
Compound Transitions (cmminus1) Assignments Geometry ESR Magnetic moment (BM)119892II 119892
perp
BEF 260 nm 120587 rarr 120587lowast mdash mdash mdash mdash370 nm 119899 rarr 120587
lowast
BEFndashCu14295 1
119861119892rarr
2119864119892
Octahedral 221 211 18516465 1119861119892rarr
2119864119892
24580 Charge transfer
BEFndashNi12474 3119879
2119892(119865) larr 3119860
2119892(119865)
Octahedral mdash mdash 30514642 31198791119892(119865) larr 3119860
2119892(119865)
24370 31198791119892(119875) larr 3119860
2119892(119865)
BEFndashZn mdash mdash Octahedral mdash mdash Diamagnetic
0 1000
Inte
nsity
2000 3000 4000 5000 6000 7000G
Figure 3 ESR spectra of BEFndashCu complex
of aromatic nucleus and 119899 rarr 120587lowast transition indicates thepresence of ndashNH groups The electronic spectrum of BEFndashCu metal complex exhibited bands at 14295 16465 and24580 cmminus1 and the assignments are 1119861
119892rarr2119864119892 1119861119892
rarr2119864119892 and charge transfer spectra which lead to a distorted
octahedral geometry with the magnetic moment of 185 BMThe electronic spectrum of BEFndashNi exhibits three bands at12474 14642 and 24370 cmminus1 assigned to the spin allowedtransitions 3119879
2119892(119865) larr 3119860
2119892(119865) 3119879
1119892(119865) larr 3119860
2119892(119865) and
31198791119892(119875) larr 3
1198602119892(119865) in an octahedral environment with a
magnetic moment of 305 BMThe diamagnetic nature of theBEFndashZn is also confirmed with octahedral geometry Basedon the literature the geometry is assigned to all the metalcomplexes [24]
The ESR spectrum of BEFndashCu complex is shown inFigure 3 and its spectral data are presented in Table 3 Thespectrum provides useful information about the metal ionenvironment in the respective complexes The ESR spectrumof BEFndashCu metal complex showed that 119892
= 221 and
119892perp= 211 lead to an octahedral environment According to
Kivelson and Neimen [25] the bond between the ligand andthe metal possesses a more covalent character than ionic In
general both the parallel and the perpendicular 119892 values canbe used to calculate the 119866 value by the following equation
119866 =119892minus 2002
119892perpminus 2002
(1)
Using the above equation the 119866 value for BEFndashCu was192 which clearly indicates that the complex forms with astrong field ligand
35 Nuclear Magnetic Resonance The NMR (1H and 13C)spectra for BEF terpolymer ligand and its zinc metal complex(due to d9 and d8 configurations both NMR spectra forcopper and nickel metal complexes are complicated) wererecorded to elucidate the structure of the ligand and itscomplex
351 1H NMR Spectra The 1H NMR spectra of BEF ter-polymer ligand and its Zn2+ metal complex are shownin Figure 4 The signals obtained for the terpolymer andits metal complexes were interpreted on the basis of thedata available in the literature [22 26] The spectrum ofterpolymer showed that the signals appearing in the region of739ndash824 ppm are assigned to all the protons of the aromaticring A peak appearing at 250 is assigned to the methyleneprotons of the terpolymer ligand The terpolymer spectrumshowed a signal appearing at 472 ppm that is assigned tothe ndashNH protons of ethylenediamine moiety and the peakappearing at 865 ppm is assigned to ndashNH proton of thiazolering A weak signal appearing at 302 ppmmay be assigned toethylenic protons of an ArndashCH
2ndashNHndashCH
2moiety
The spectrum of the Zn2+ complex showed multiplet inthe range of 740ndash824 ppm is assigned to the aromatic protonsand the methylene protons appeared at 215ndash250 ppm Thesignal obtained at 508 ppm is assigned to ndashNH protons ofethylenediamine and this shift from its ligand gives a clearevidence for the complexation of the ligand with the metalions through the lone pair of nitrogen of ethylenediaminemoiety
352 13C NMR Spectra The 13C NMR spectra of the BEFterpolymer ligand and its Zn2+ metal complex are shown in
Bioinorganic Chemistry and Applications 7
(ppm)
12345678910
(a)
(ppm)1 0234567891011
(b)
Figure 4 1H-NMR spectra of (a) BEF ligand and (b) BEFndashZn
200 180 160 140 120 100 80 60 40 20 0(ppm)
(a)
200 180 160 140 120 100 80 60 40 20 0(ppm)
(b)
Figure 5 13C-NMR spectra of (a) BEF ligand and (b) BEFndashZn
O2N S
N
NH NH
M
NHCH2 CH2 CH2 CH2
n
O2NS
NNH NH NHCH2 CH2 CH2 CH2
n
H2OH2O
[M = Cu(II) Ni(II) and Zn(II)]
Figure 6 Proposed geometry of BEF metal complexes
Figure 5 The observed chemical shifts are assigned on thebasis of the literature [22 27]The spectrum of ligand showedthat the corresponding peaks at 1717 1585 1315 1219 14061167 and 1253 ppm are attributed to the aromatic carbonsof the benzothiazole ring The peak appearing at 502 ppmis assigned to the methylenic carbon of NHndashCH
2bridge in
the ligand The spectrum of Zn2+ complex showed the peaksfor aromatic ring in the same region which was appearingin its parent ligand The shifting of the methylene carbonfrom 502 to 561 ppm from its ligand clearly suggests that the
coordination takes place between the nitrogen atoms of theethylenediamine moiety
From the elemental and spectral data (FTIR UV-VisESR and NMR (1H and 13C)) the structure of the BEF ter-polymer ligand and its metal complexes has been confirmedThe proposed geometry of the BEF complexes is shown inFigure 6
36 Surface Analysis The SEM is applied to understandthe surface features of the polymeric materials The SEM
8 Bioinorganic Chemistry and Applications
(a) (b)
(c) (d)
(e)
Figure 7 SEM images of (a) and (b) BEF ligand (c) BEFndashCu (d) BEFndashNi and (e) BEFndashZn
photographs in times1000 and times2000 magnifications for BEFligand and times3000 magnifications for BEF complexes areshown in Figure 7 The white bar at the bottom of the SEMphotographs represents the scale The SEM photographs ofthe BEF terpolymer ligand show leaf like appearance Thescattered structure of the terpolymer establishes a transitionstate between the crystalline and the amorphous phases [28]
Themorphology of BEF terpolymer resin exhibits growthof crystals from polymer solutions corresponding to the
most prominent organization in polymers on a large scalewith spherulites Ideally spherulites are the aggregates ofsubmicroscopic size particles Spherulites are characterizedby secondary structural features such as faint corrugationsThe SEM photographs of polymers have an appreciableamorphous fraction with a small amount of shallow pitsThe surface of BEF metal complexes contributes to greatersegments of crystalline regions compared to their parentligand which may arise from the contraction of the voids by
Bioinorganic Chemistry and Applications 9
Inte
nsity
(au
)
0 20 40 60 802120579
(a)
Inte
nsity
(au
)
0 20 40 60 802120579
(b)
Inte
nsity
(au
)
0 20 40 60 802120579
(c)
Inte
nsity
(au
)
0 20 40 60 802120579
(d)
Figure 8 XRD patterns of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
the cooperative contribution of the ligand for complexationwith metal ions or the disappearance of the voids in therearrangement of polymer chains for complexation withmetal ions This is a further evidence for the complexationof BEF terpolymer with metal ions
37 XRD Studies X-ray diffraction (XRD) patterns of BEFand its metal complexes are shown in Figure 8 It provides adetailed comparative account of the behavior of the terpoly-mer and itsmetal complexesThepattern of BEF ligand showsthe main characteristic peak and broad shoulder In view ofthe relative half value width it may be concluded that thepolymer is partially crystalline and the broad characteristicpeak indicates the amorphous nature of the terpolymerTherefore the BEF terpolymer has transition state betweenamorphous state and crystalline state whereas its metalchelates possess crystalline nature The enhanced crystallinebehavior of the BEF complexes may be due to the insertion ofmetal ions with their parent ligand [29]
38 Thermal Stability Thermal stability of the BEF terpoly-mer and its metal complexes was analyzed by thermogravi-metric analysis (TGA) The thermograms of the terpolymer
and its metal complexes are shown in Figure 9 and their per-centages of weight loss at various temperatures are presentedin Table 4
381Thermal Stability of BEF Terpolymer From the thermo-gram of BEF terpolymer there were three stages of degra-dation (200ndash320∘C 320ndash580∘C and 580ndash835∘C) observedThe first stage of degradation was observed between 200∘Cand 320∘C (found 5883 calc 5794) which reveals thedegradation of the benzothiazole ring The second stageof degradation begins at 320∘C and ends at 580∘C (found1003 calc 0931) which may be due to the eliminationof cross-linkages The third and final stage of degradation isobserved above 580∘C and continued up to 825∘C (found2506 calc 2473) which can be attributed to the weightloss of aliphatic group (ethylenediamine moiety) from theBEF terpolymer
382 Thermal Stability of BEF Metal Complexes In generalthe water of hydration may be considered as either crystalwater molecules or coordination water molecules Accordingto Nikolaev et al [30] water eliminated below 150∘C can beconsidered as crystal or lattice water and water eliminated
10 Bioinorganic Chemistry and Applications
Table 4 TGA data for thermal stability
Compound Percentage of weight loss at various temperatures11987950
lowast (∘C) 119879maxlowastlowast (∘C)
100 200 300 400 500 600 700 800 (∘C)BEF ligand 0153 0365 4414 6236 6718 7140 8224 9442 310 825BEFminusCu 0194 1432 3180 4301 4996 5549 6686 8122 500 860BEFminusNi 0893 1660 3735 4935 6460 8767 mdash mdash 405 650BEFminusZn 1464 2262 3833 4616 5726 6492 7614 9129 425 830lowastTemperature of 50 weight loss lowastlowastmaximum decomposition temperature
80
60
40
20
0
0
(a)(b)
(c)(d)
200 400 600 800 1000
100
Wei
ght (
)
Temperature (∘C)
Figure 9 TGA of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d)BEFndashZn
above 150∘C may be due to its coordination to the metalatom present in chelates In the present study in the case ofBEFndashCu2+ Ni2+ and Zn2+ complexes the removal of waterfrom the complex was completed within 150∘C These watermolecules are probably crystal or lattice water moleculesTheremoval of water molecules observed in the range of 150ndash200∘C (found 559ndash608 calc 545ndash551) of all the metalchelates is due to the elimination of two coordinated watermolecules These observations further confirm the distortedoctahedral geometry of BEF metal complexes
The thermogravimetric curves of all the BEF metalchelates showed two degradation steps after loss of watermolecules whichmay indicate that the first step (200ndash600∘C)is faster than the second step (600ndash860∘C) This may bedue to the fact that the noncoordinated part of the liganddecomposes firstwhile the coordinated part decomposes laterand finally it may form the representative metal oxides Theweight of the residues confirms fairly well that ofmetal oxides(found 1247ndash1362 calc 1143ndash1232)
The thermal degradation data of the BEF terpolymerand its metal complexes reveal that the polymeric complexesshow better stability than the BEF terpolymer due to thecoordination of metal ions The order of thermal stability ofthe BEF polymer and its complexes is BEFndashCu2+ gt BEFndashZn2+ gt BEF ligand gt BEFndashNi2+ The greater stability of themetal complexes may be due to the coordination and theenhanced cross linking nature with crowd effect of the metal
complexes [31] In the case of Ni2+ complex the degradationoccurred exceptionally at low temperature compared to theirligand which may be due to the oxidation of polymer by thecatalytic action of the metal ion [32]
383 Thermal Kinetics
(1) Sharp-Wentworth and Freeman-Carroll Method Ther-mal kinetic analysis was performed using Sharp-Wentworthmethod and Freeman-Carroll methods The activationenergy (119864
119886) and order of reaction (119899) plots for BEF terpoly-
mer ligand and its metal complexes by Sharp-Wentworthand Freeman-Carroll methods are shown in Figures 10 11and 12 The expressions used to calculate the kinetic andthermodynamic parameters are presented as follows
(i) Entropy change (Δ119878)
Intercept = log 119870119877
ℎΦ119864119886
+Δ119878
2303119877 (2)
where 119870 = 13806 times 10minus16 ergdegmole 119877 =
1987 caldegmole (8314 JKMol) ℎ = 6625 times
10minus27 erg sec Φ = 0166 Δ119878 = change in entropyand 119864
119886= activation energy from graph
(ii) Free energy change (Δ119865)
Δ119865 = Δ119867 minus 119879Δ119878 (3)
where Δ119867 = enthalpy change = activation energy 119879 =temperature in119870 and Δ119878 = result from (2)
(iii) Frequency factor (119885)
11986123
=log119885119864
119886
119877Φ (4)
11986123
= log 3 + log [1 minus 3radic1 minus 120572] minus log119901 (119909) (5)
where 119885 is the frequency factor 119861 is calculatedfrom (5) log119901(119909) is calculated from Doylersquos tablecorresponding to activation energy and 120572 is degreeof transformation (120572 = 119908119882
119888)
(iv) Apparent entropy (119878lowast)
119878lowast= 2303 log 119885ℎ
119877119879lowast (6)
where119885 is calculated from (4) and 119879lowast is half decom-position temperature
Bioinorganic Chemistry and Applications 11
1000T (Kminus1)
Intercept = minus535
minus45
minus50
minus55
minus60
minus65
minus70
minus75
minus80
10 15 20 25 30
Ea = 952
log[
(dC
dT
)(1
minusC
)]
(a)
minus64
minus62
minus60
minus58
minus56
minus54
minus52
1000T (Kminus1)10 15 20 25 30
Intercept = minus527
Ea = 1297
log[
(dC
dT
)(1
minusC
)]
(b)
minus64
minus62
minus50
minus52
minus54
minus56
minus58
minus60
1000T (Kminus1)10 15 20 25 30
Intercept = minus513
Ea = 693
log[
(dC
dT
)(1
minusC
)]
(c)
minus50
minus51
minus52
minus53
minus54
minus55
minus56
minus57
minus58
minus59
1000T (Kminus1)10 15 20 25 30
Intercept = minus538
Ea = 1108
log[
(dC
dT
)(1
minusC
)]
(d)
Figure 10 Sharp-Wentworth plots of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Table 5 Kinetic and thermodynamic parameters data
CompoundActivation energy
(119864119886kJmolminus1) Entropy change
(Δ119878J)Free energy
change (Δ119865kJ)Frequency
factor (119885sminus1)Apparent
entropy (119878lowastJ)Order of
reaction (119899)lowastSW lowastlowastFC
BEF ligand 952 1039 minus15811 5940 1310 minus2295 090BEFminusCu 1297 1367 minus15425 9079 1205 minus2331 104BEFminusNi 693 460 minus16290 7057 1537 minus2294 093BEFminusZn 1108 1213 minus16001 8013 1243 minus2318 102lowastSW Sharp-Wentworth lowastlowastFC Freeman-Carroll
Further from the knowledge of activation energy cal-culated by Freeman-Carroll method it is possible to eval-uate the values of various thermodynamic parameters Theorder of reaction (119899) and activation energy (119864
119886) and the
thermodynamic parameters such as frequency factor (119885)entropy change (Δ119878) free energy change (Δ119865) and apparententropy (119878lowast) are presented inTable 5The119864
119886values calculated
by SW and FC methods are in good agreement with eachother The order of activation energies for BEF ligand andits Cu2+ Ni2+ and Zn2+ complexes is parallel to the orderof their thermal stability [32] The values of thermodynamic
parameters were comparable indicating a common modeof decomposition reaction The abnormal low values offrequency factor (119885) indicate that the decomposition reactionof BEF terpolymer and its metal complexes can be depictedas a slow reaction The order of reactions (119899) of BEF ligandand its metal complexes is found to be 090 104 093 and102 respectively Hence the BEF terpolymer and its mealcomplexes may be following nearly a first order kinetics
(2) Phadnis-Deshpande Method The activation energiescalculated for BEF ligand and its metal complexes using
12 Bioinorganic Chemistry and Applications
minus00012minus00010minus00008minus00006minus00004minus00002minus00000
26242220181614121008060402
log(dWdt)
(1T)
n = 090
logW
r
logWr
(a)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
20
19
18
17
16
15
14
13
12
11
10
log(dWdt)
(1T)
n = 104
logWr
logW
r
(b)
15
16
17
18
19
14
13
12
11
10
09
log(dWdt)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
(1T)
n = 093logW
r
logWr
(c)
15
16
17
18
14
13
12
11
10
log(dWdt)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
(1T)
n = 102
logW
r
logWr
(d)
Figure 11 Freeman-Carroll plots (119899) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Phadnis-Deshpande method are presented in Table 6 Fromthe 119864
119886values it is possible to propose the degradation
reactionmechanism using PDmethod Further the 119864119886values
calculated by PD method are in good agreement with FCand SW methods Based on the closest 119864
119886values calculated
by PD SW and FC methods the Power law mechanismsuits very well for the BEF ligand and BEFndashCu and BEFndashZn metal complexes However BEFndashNi complex follows theBrounshtein-Ginstling 3-dimensional diffusion mechanism
39 Biological Studies
391 Antibacterial Activity To determine the antibacterialactivity of the BEF terpolymer and its Cu2+ Ni2+ andZn2+ complexes the disc diffusion method was used withamoxicillin as the standard antibiotic The prepared com-pounds were tested against Shigella sonnei Escherichia coliKlebsiella species Staphylococcus aureus Bacillus subtilis andSalmonella typhimuriummicroorganisms
Table 7 contains the screening results corresponding tothe polymeric ligand and its metal complexes with fairinhibition of growth against the tested organisms Shigella
sonnei is a nonmotile non-spore-forming and facultativeanaerobic gram-negative bacterium Shigella bacteria multi-ply within colonic epithelial cells and cause mucosal ulcer-ation inflammation bleeding high fever malaise diarrheaand tenesmus The ligand and its metal complexes showeda reasonable activity against the S sonnei species E coliis an aerobic gram-negative and rod shaped bacteriumInfection of E coli can lead to bloody diarrhea and kidneyfailureThe polymeric ligand and its complexes hold amodestactivity against the E coli Klebsiella is a genus of nonmotileand gram-negative bacteria that infects sites such as nasalpassages liver lung urinary tract bloodstream eye boneand joints It causes a wide range of disease states notablypneumonia septicemia soft tissue infections biliary tractinfection infection of the upper and lower respiratory tractand liver abscess The BEF ligand and its metal complexesshowed a reasonable result against the growth of KlebsiellaStaphylococcus aureus a gram-positive and spherical bac-terium leads to life-threatening diseases like pneumoniaosteomyelitis endocarditis and toxic shock syndrome Toxicshock syndrome is characterized by the sudden onset of highfever vomiting diarrhea and muscle aches followed by lowblood pressure (hypotension) which can lead to shock and
Bioinorganic Chemistry and Applications 13
log[g
(120572)T3]
minus95
minus90
minus85
minus80
minus75
10 15 20 25 30
Intercept = minus825
Ea = 1039
1000T (Kminus1)
(a)
log[g
(120572)T3]
minus78
minus80
minus82
minus84
minus86
minus88
minus90
minus92
minus94
minus96
minus76
Intercept = minus805
Ea = 1367
10 15 20 25 30
1000T (Kminus1)
(b)
log[g
(120572)T3]
minus77
minus78
minus79
minus80
minus81
minus82
minus83
minus84
minus85
minus86
minus87
minus88minus89
Intercept = minus849
Ea = 460
10 15 20 25 30
1000T (Kminus1)
(c)
minus78
minus80
minus82
minus84
minus86
minus7610 15 20 25 30
1000T (Kminus1)
log[g
(120572)T3]
Intercept = minus835
Ea = 1213
(d)
Figure 12 Freeman-Carroll plots (119864119886) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Table 6 Activation energies calculated by Phadnis-Deshpande method
Reaction mechanism model Energy of activation (119864119886) (kJmol)
BEF ligand BEFminusCu BEFminusNi BEFminusZnPower law 60932 62642 59691 54312Power law 121864 125284 119382 108625Phase boundary (contracting sphere) 16497 16816 16174 15009Phase boundary (contracting cylinder) 25894 26436 25383 23466Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 12135 13830 11756 07447
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 08090 09220 07837 04964
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 06067 06915 05878 03723
Valensi 2-dimensional diffusion 168354 171926 165034 152695Jander 3-dimensional diffusion 32995 33632 32349 30018Brounshtein-Ginstling 3-dimensional diffusion 56520 55015 55669 57981The values indicated in bold are closest to the 119864119886 value estimated by FC and SWmethods
14 Bioinorganic Chemistry and Applications
Table 7 Antibacterial activity of BEF ligand and its complexes
Compound Inhibition zone (mm)S sonnei E coli Klebsiella sp S aureus B subtilis S typhi
BEF ligand 15 13 13 14 15 12BEFndashCu 21 17 17 18 18 18BEFndashNi 18 15 18 17 20 15BEFndashZn 16 15 15 16 17 15Standard 26 28 26 25 27 28Control mdash mdash mdash mdash mdash mdashStandard amoxicillin control DMSO
Table 8 Antifungal activity of BEF ligand and its complexes
Compound Inhibition zone (mm)Aspergillus flavus Aspergillus niger Penicillium species Candida albicans Cryptococcus neoformans Mucorspecies
BEF ligand 14 12 12 13 11 12BEFndashCu 20 18 19 18 15 19BEFndashNi 17 14 17 15 13 13BEFndashZn 15 15 18 17 14 16Standard 20 21 19 21 18 22Control mdash mdash mdash mdash mdash mdashStandard fluconazole control DMSO
death There may be a rash resembling sunburn with peelingof skin The ligand and its complexes showed a humbleactivity against the growth of S aureus Bacillus subtilis arerod-shaped and nonpathogenic gram-positive bacteria TheBEF ligand and complexes showed superb activity againstthe growth of this bacterium Salmonella typhimurium is apathogenic gram-negative bacteria predominately found inthe intestinal lumen When the bacterial cells enter epithelialcells lining the intestine they cause host cell ruffling whichtemporarily damages the microvilli on the surface of the cellThis causes a rush of white blood cells into the mucosa andleads to diarrheaThe ligand and its metal complexes showeda moderate activity against the growth of the typhi species
A comparative account on the effect of antibacterialactivity against the chosen microbes indicates that the ligandand its three metal chelates show reasonable activity againstShigella sonnei (15 21 18 and 16mm) and Bacillus subtilis (1518 20 and 17mm) while the growth of other organisms ismoderately inhibited by the BEF ligand and its Cu2+ Ni2+and Zn2+ chelates The highest antibacterial action (21mm)has been observed for BEFndashCu2+ complex against Shigellasonnei
392 Antifungal Activity The antifungal activity of the BEFligand and its metal complexes has also given interestingresults and the growth inhibitions against the chosen fungalstrains are tabulated in Table 8 All the complexes and theirligand have an excellent activity against Aspergillus flavusa mold type fungal strain which may invade arteries of thelung or brain to cause infections and also produce a toxinAspergillus niger is one of the most common causes for
otomycosis The chelates and the ligand are found to havea reasonable activity for A niger Penicillium species causesinfection in humans and the resulting disease is known gener-ically as penicilliosis The ligand and the metal complexeshave wonderful activity against this species Further BEFndashCucomplex has a superior activity compared to the rest of othercomplexes Candida albicans is a diploid fungus and a causalagent of opportunistic oral and genital infections in humansand also emerged as an important cause of morbidity andmortality in immunocompromised patients The BEF ligandand its chelates possess a modest activity against C albicansover and above the standard Cryptococcus neoformans is anencapsulated yeast-like fungus that can live in both plantsand animals and cause lung infection The terpolymer ligandand its chelates have a fair activity against this fungal strainThe chelate compounds and the ligand havemoderate activityagainst Mucor species a filamentous fungus which causesseptic arthritis renal infections and pulmonary infections
From the antimicrobial results themetal complexes showhigher activity than their ligand which may be stronglydependent on the central metal ions and coordination num-bers metal chelates The higher activity due to the metal ionsshared with the donor atoms (N and S) of the thiazole ring ispresent in the ligand and the 120587-electron delocalization overthe chelate ring This effect increases the lipophilic characterof the metal ion which favors the permeation through thelipoid layers of the bacterial and fungal membranes [33 34]It is perceived that the factors such as solubility conductivitydipole moment and cell permeability may also contributeto the increased activity of the complexes [35 36] Fromthe results of the studies at 500 ppm concentration thecompounds establish better antimicrobial activity Hence it
Bioinorganic Chemistry and Applications 15
is an interesting result that a very low concentration of thecompound namely 500 ppm is enough to bring out aneffective inhibition against the chosen microbes
4 Conclusion
The synthesized 2-amino-6-nitro-benzothiazole-ethylene-diamine-formaldehyde terpolymer has acted as a ligandsuccessfully to form metal complexes The synthesized com-pounds were well characterized by various spectral andphysical analyses The morphological features suggest thatthe complexes are slightly more crystalline in nature thantheir parent ligandThe antibacterial and antifungal activitiesreveal that the terpolymer and its metal complexes can beactive against the selected bacterial and fungal strains Nearlyall of the compoundsmay suit well for drug delivery field afterchecking for their toxicology behaviour in thorough mannerThermal studies are also helpful to realize the standing capac-ity of the compounds which survive as antimicrobial coatingmaterials in various environmental conditions Because ofthe proven high stability nature and microbial preventioncapacity the BEF terpolymer and its Cu2+ Ni2+ and Zn2+complexes hold inadequate applications in biological fieldThe thermal stability of the terpolymer and its metal com-plexes was found greater From the thermodynamic andkinetic studies the abnormal low values of frequency factor(119885) indicate that the thermal decomposition reaction of BEFterpolymer and its metal complexes can be depicted as a slowreaction The BEF terpolymer and its metal complexes maybe following nearly a first order kinetics
Conflict of Interests
The authors certify that there is no conflict of interests withany financial organization regarding thematerial discussed inthe paper
Acknowledgments
The authors thank the Management and Principal ofOxford Engineering College Tiruchirappalli CoimbatoreInstitute of Technology Coimbatore Jamal Mohamed Col-lege (Autonomous) Tiruchirappalli Tamil Nadu and DrD Jeyakumar Scientist Central Electrochemical ResearchInstitute (CECRI-CSIR) Karaikudi Tamil Nadu for theirsupport and encouragement
References
[1] C U Pittman K S Ramachandran Jr and K R LowyerldquoSynthesis of fungicidal monomers polymers and latticesrdquoJournal of Coating Technology vol 54 pp 27ndash40 1982
[2] M N Patel J R Patel and D H Sutaria ldquoNovel co-ordinationpolychelatesrdquo Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry vol 24 no 8 pp 1297ndash1309 1994
[3] V V Ukey and H D Juneja ldquoSynthetic and spectroscopicstudies of chelate polymers involving azelaoyl bis-N-phenylhydroxamic acid with transition metal ionsrdquo Journal of AppliedPolymer Science vol 99 no 1 pp 273ndash278 2006
[4] S K-H Thiele and D R Wilson ldquoAlternate transition metalcomplex based diene polymerizationrdquo Polymer Reviews vol 43no 4 pp 581ndash628 2003
[5] N Nishat S Ahmad and T Ahamad ldquoSynthesis and character-ization of antibacterial polychelates of urea-formaldehyde resinwith Cr(III) Mn(II) Fe(III) Co(II) Ni(II) Cu(II) and Zn(II)metal ionsrdquo Journal of Applied Polymer Science vol 100 no 2pp 928ndash936 2006
[6] E Brzezinska G Koska and K Walczynski ldquoApplicationof thin-layer chromatographic data in quantitative structure-activity relationship assay of thiazole and benzothiazole deriva-tives with Hmdashantihistamine activityrdquo Journal of Chromatogra-phy A vol 1007 pp 145ndash155 2003
[7] M A R Ahamed and A R Burkanudeen ldquoMetal complexesof a novel terpolymer ligand synthesis spectral morphologythermal degradation kinetics and antimicrobial screeningrdquoJournal of Inorganic andOrganometallic Polymers andMaterialsvol 22 no 5 pp 1046ndash1061 2012
[8] B S Holla K V Malini V S Rao B K Sarojini and N SKumari ldquoSynthesis of some new 24-disubstituted thiazoles aspossible antibacterial and anti-inflammatory agentsrdquo EuropeanJournal of Medicinal Chemistry vol 38 no 3 pp 313ndash318 2003
[9] O I El-Sabbagh M M Baraka S M Ibrahim et al ldquoSynthesisand antiviral activity of new pyrazole and thiazole derivativesrdquoEuropean Journal of Medicinal Chemistry vol 44 no 9 pp3746ndash3753 2009
[10] A Andreani M Granaiola A Leoni A Locatelli R Morigiand M Rambaldi ldquoSynthesis and antitubercular activity ofimidazo[21-b]thiazolesrdquo European Journal of Medicinal Chem-istry vol 36 no 9 pp 743ndash746 2001
[11] E Yousif Y Farina K Kasar A Graisa and K Ayid ldquoCom-plexes of 2-thioacetic acid benzothiazole with somemetal ionsrdquoAmerican Journal of Applied Sciences vol 6 no 4 pp 582ndash5852009
[12] B P Mallikarjuna B S Sastry G V Suresh Kumar Y Rajen-draprasad S M Chandrashekar and K Sathisha ldquoSynthesis ofnew 4-isopropylthiazole hydrazide analogs and some derivedclubbed triazole oxadiazole ring systemsmdasha novel class ofpotential antibacterial antifungal and antitubercular agentsrdquoEuropean Journal of Medicinal Chemistry vol 44 pp 4739ndash4746 2009
[13] T Ahamad V Kumar and N Nishat ldquoNew class of anti-microbial agents synthesis characterization and anti-microbial activities of metal chelated polyureardquo Journal ofBiomedical Materials Research A vol 88 no 2 pp 288ndash2942009
[14] M V Patel J N Patel M B Dolia and R M Patel ldquoPolyether-ketones synthesis characterization and antimicrobial activityrdquoInternational Journal of Polymeric Materials and PolymericBiomaterials vol 54 no 11 pp 1059ndash1071 2005
[15] K R Alagawadi and S G Alegaon ldquoSynthesis characteriza-tion and antimicrobial activity evaluation of new 24-Thiazoli-dinediones bearing imidazo[21-b][134]thiadiazole moietyrdquoArabian Journal of Chemistry vol 4 no 4 pp 465ndash472 2011
[16] M Ashok B S Holla and N S Kumari ldquoConvenientone pot synthesis of some novel derivatives of thiazolo[23-b]dihydropyrimidinone possessing 4-methylthiophenyl moietyand evaluation of their antibacterial and antifungal activitiesrdquoEuropean Journal ofMedicinal Chemistry vol 42 no 3 pp 380ndash385 2007
16 Bioinorganic Chemistry and Applications
[17] T Ahamad V Kumar S Parveen and N Nishat ldquoIn vitroantibacterial and antifungal assay of poly-(ethylene oxamide-NN1015840-diacetate) and its polymer-metal complexesrdquo AppliedOrganometallic Chemistry vol 21 no 12 pp 1013ndash1021 2007
[18] R S Azarudeen M A R Ahamed and A R BurkanudeenldquoBiological and thermal investigations of polychelates derivedfrom a novel terpolymer ligandrdquo Journal of Polymer Researchvol 18 no 6 pp 1331ndash1341 2011
[19] R S Azarudeen and A R Burkanudeen ldquoSynthesis spectralmorphology thermal degradation kinetics and antibacterialstudies of terpolymermetal complexesrdquo Journal of Inorganic andOrganometallic Polymers and Materials vol 22 no 4 pp 791ndash806 2012
[20] R S Azarudeen and A R Burkanudeen ldquoStudies of newoligomer-metal complexes and their antibacterial activitiesrdquoPolymer International vol 62 no 3 pp 362ndash374 2013
[21] G S Devi A K Muthu D S Kumar S Rekha R Indhumathiand R Nandhini ldquoStudies on the antibacterial and antifungalactivities of the ethanolic extracts of Luffa cylindrica (Linn)fruitrdquo International Journal of Drug Development and Researchvol 1 pp 105ndash109 2013
[22] R M Silverstein and G C Bassler Spectrometric IdentificationofOrganic Compounds JohnWileyamp SonsNewYorkNYUSA2nd edition 1967
[23] Y-G Zhao H-Y Shen S-D Pan and M-Q Hu ldquoSyn-thesis characterization and properties of ethylenediamine-functionalized Fe
3O4magnetic polymers for removal of Cr(VI)
in wastewaterrdquo Journal of Hazardous Materials vol 182 no 1-3pp 295ndash302 2010
[24] Y R Sharma Elementary Organic Absorption Spectroscopy SChand amp Co Ltd New Delhi India 1980
[25] D Kivelson and R Neiman ldquoESR line shapes in glasses ofcopper complexesrdquoThe Journal of Chemical Physics vol 35 no1 pp 149ndash155 1961
[26] E Pretsch P Buhlmann and C Afflolter Structure Determi-nation of Organic Compounds Springer New York NY USA2000
[27] J L White Modern Magnetic Resonance Kluwer AcademicPress London UK 2006
[28] M M Patel M A Kapadia and J D Joshi ldquoThermal andcatalytic aspects of Ln(III) polymer-metal complexesrdquo PolymerInternational vol 58 no 7 pp 728ndash737 2009
[29] S Nanjundan C S J Selvamalar and R Jayakumar ldquoSynthesisand characterization of poly(3-acetyl-4-hydroxyphenyl acry-late) and its Cu(II) and Ni(II) complexesrdquo European PolymerJournal vol 40 no 10 pp 2313ndash2321 2004
[30] A V Nikolaev V A Logvinenco and L I Myachina ThermalAnalysis Academic Press New York NY USA 1969
[31] A Z El-Sonbati and M A Hefni ldquoPolymer complexes PartXXVImdashNovel mixed ligand poly-(5-vinyl salicylidene)-12-diaminobenzene complexesrdquo Polymer Degradation and Stabil-ity vol 43 no 1 pp 33ndash42 1994
[32] A S Aswar and N S Bhave ldquoThermal degradation studies ofsome new coordination polymersrdquo Polymer Degradation andStability vol 31 no 1 pp 115ndash124 1991
[33] T Ahamad V Kumar and N Nishat ldquoSynthesis characteri-zation and antimicrobial activity of transition metal chelatedthiourea-formaldehyde resinrdquo Polymer International vol 55no 12 pp 1398ndash1406 2006
[34] M M Patel M A Kapadia G P Patel and J D Joshi ldquoSynthe-sis characterization ion-exchange and antimicrobial study of
poly[(2-hydroxy-4-methoxybenzophenone) propylene] resinand its polychelates with lanthanides (III)rdquo Journal of AppliedPolymer Science vol 106 no 2 pp 1307ndash1317 2007
[35] M A Neelakantan S S Marriappan J Dharmaraja T Jeyaku-mar and K Muthukumaran ldquoSpectral XRD SEM and bio-logical activities of transition metal complexes of polydentateligands containing thiazole moietyrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 71 no 2 pp 628ndash635 2008
[36] G B Bagihalli S A Patil and P S Badami ldquoSynthesisphysicochemical investigation and biological studies of zinc(II)complexes with 124-triazole schiff basesrdquo Journal of the IranianChemical Society vol 6 no 2 pp 259ndash270 2009
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Inorganic ChemistryInternational Journal of
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Carbohydrate Chemistry
International Journal of
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Journal of
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Advances in
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Analytical Methods in Chemistry
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Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
SpectroscopyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chromatography Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Applied ChemistryJournal of
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Theoretical ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Spectroscopy
Analytical ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Quantum Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Organic Chemistry International
ElectrochemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CatalystsJournal of
Bioinorganic Chemistry and Applications 5
Table 1 Physicochemical and analytical data
Compound Empirical formula ofthe repeating unit Formula mass
Elemental analysis ()Λ (Ωminus1 cm2 molminus1)Found (calc)
C H N S MBEF ligand C11H13N5O2S 27936 4709 (4729) 416 (435) 2521 (2549) 1120 (1139) mdash mdashBEFndashCu C22H26N10O4S2Cusdot2H2O 65823 4071 (4092) 439 (462) 2174 (2194) 919 (927) 931 (962) 13205BEFndashNi C22H26N10O4S2Nisdot2H2O 65334 4025 (4037) 447 (479) 2129 (2146) 962 (983) 926 (945) 9837BEFndashZn C22H26N10O4S2Znsdot2H2O 66010 4023 (4052) 423 (445) 2138 (2153) 912 (929) 941 (970) 11329C carbon H hydrogen N nitrogen S sulphur and M metal ion
Table 2 FTIR data
Compound Observed frequencies (cmminus1)BEF ligand BEFndashCu BEFndashNi BEFndashZn
] NH (asym and sym) 3455minus3297 3408ndash3296 3348ndash3295 3345ndash3280] NH (bending) 1532 1527 1526 1521CH (stretching) 2731 2697 2712 2725] CH2 (asym and sym) 3078ndash2936 3093ndash2912 3098ndash2932 3087ndash2945] CH2 (bending in NndashCH2ndashCH2ndashN) 1450 1448 1449 1446268-tri substitution (benzothiazole) 1296minus825 1298ndash825 1293ndash827 1292ndash825] NrarrM mdash 432 433 433] CndashNO2 1505ndash1518 1503ndash1576 1524ndash1575 1513ndash1583] C=N 1540 1590 1586 1580] CndashSndashC 740 753 763 748
Tran
smitt
ance
()
(a)
4000 3500 3000 2500 2000 1500 1000 500
(b)
(c)
(d)
Wavenumber (cmminus1)
Figure 1 FTIR spectra of (a) BEF (b) BEFndashCu (c) BEFndashNi and (d)BEFndashZn
in the ethylenediamine moiety It is a clear evidence for theinvolvement of nitrogen atoms in the chelationThis is furthersupported by the appearance of ]NrarrM stretching vibrationat 432ndash433 cmminus1
34 Electronic and ESR Spectra and Magnetic MomentsThe electronic spectra of the BEF terpolymer and its metalcomplexes are shown in Figure 2 and the data are presentedin Table 3 The spectrum of the ligand showed two bands at
100
Abso
rban
ce
050
0400
Wavelength (nm)600200 800
(d)(c)(b)
(a) (d)((c)(b)((((
(a)aaaaa
Figure 2 Electronic spectra of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
260 and 370 nmThese observed positions for the absorptionbands have different intensitiesThe less intense band 260 nmis due to (120587 rarr 120587
lowast) allowed transition of chromophoregroups like NO
2 gtC=N and C=C which are in conjugation
with an aromatic nucleus (benzothiazole ring) and the moreintense band 370 nm may be due to (119899 rarr 120587
lowast) transition ofndashNH groupsThus 120587 rarr 120587lowast transition indicates the presence
6 Bioinorganic Chemistry and Applications
Table 3 UV-Visible ESR data and magnetic moments
Compound Transitions (cmminus1) Assignments Geometry ESR Magnetic moment (BM)119892II 119892
perp
BEF 260 nm 120587 rarr 120587lowast mdash mdash mdash mdash370 nm 119899 rarr 120587
lowast
BEFndashCu14295 1
119861119892rarr
2119864119892
Octahedral 221 211 18516465 1119861119892rarr
2119864119892
24580 Charge transfer
BEFndashNi12474 3119879
2119892(119865) larr 3119860
2119892(119865)
Octahedral mdash mdash 30514642 31198791119892(119865) larr 3119860
2119892(119865)
24370 31198791119892(119875) larr 3119860
2119892(119865)
BEFndashZn mdash mdash Octahedral mdash mdash Diamagnetic
0 1000
Inte
nsity
2000 3000 4000 5000 6000 7000G
Figure 3 ESR spectra of BEFndashCu complex
of aromatic nucleus and 119899 rarr 120587lowast transition indicates thepresence of ndashNH groups The electronic spectrum of BEFndashCu metal complex exhibited bands at 14295 16465 and24580 cmminus1 and the assignments are 1119861
119892rarr2119864119892 1119861119892
rarr2119864119892 and charge transfer spectra which lead to a distorted
octahedral geometry with the magnetic moment of 185 BMThe electronic spectrum of BEFndashNi exhibits three bands at12474 14642 and 24370 cmminus1 assigned to the spin allowedtransitions 3119879
2119892(119865) larr 3119860
2119892(119865) 3119879
1119892(119865) larr 3119860
2119892(119865) and
31198791119892(119875) larr 3
1198602119892(119865) in an octahedral environment with a
magnetic moment of 305 BMThe diamagnetic nature of theBEFndashZn is also confirmed with octahedral geometry Basedon the literature the geometry is assigned to all the metalcomplexes [24]
The ESR spectrum of BEFndashCu complex is shown inFigure 3 and its spectral data are presented in Table 3 Thespectrum provides useful information about the metal ionenvironment in the respective complexes The ESR spectrumof BEFndashCu metal complex showed that 119892
= 221 and
119892perp= 211 lead to an octahedral environment According to
Kivelson and Neimen [25] the bond between the ligand andthe metal possesses a more covalent character than ionic In
general both the parallel and the perpendicular 119892 values canbe used to calculate the 119866 value by the following equation
119866 =119892minus 2002
119892perpminus 2002
(1)
Using the above equation the 119866 value for BEFndashCu was192 which clearly indicates that the complex forms with astrong field ligand
35 Nuclear Magnetic Resonance The NMR (1H and 13C)spectra for BEF terpolymer ligand and its zinc metal complex(due to d9 and d8 configurations both NMR spectra forcopper and nickel metal complexes are complicated) wererecorded to elucidate the structure of the ligand and itscomplex
351 1H NMR Spectra The 1H NMR spectra of BEF ter-polymer ligand and its Zn2+ metal complex are shownin Figure 4 The signals obtained for the terpolymer andits metal complexes were interpreted on the basis of thedata available in the literature [22 26] The spectrum ofterpolymer showed that the signals appearing in the region of739ndash824 ppm are assigned to all the protons of the aromaticring A peak appearing at 250 is assigned to the methyleneprotons of the terpolymer ligand The terpolymer spectrumshowed a signal appearing at 472 ppm that is assigned tothe ndashNH protons of ethylenediamine moiety and the peakappearing at 865 ppm is assigned to ndashNH proton of thiazolering A weak signal appearing at 302 ppmmay be assigned toethylenic protons of an ArndashCH
2ndashNHndashCH
2moiety
The spectrum of the Zn2+ complex showed multiplet inthe range of 740ndash824 ppm is assigned to the aromatic protonsand the methylene protons appeared at 215ndash250 ppm Thesignal obtained at 508 ppm is assigned to ndashNH protons ofethylenediamine and this shift from its ligand gives a clearevidence for the complexation of the ligand with the metalions through the lone pair of nitrogen of ethylenediaminemoiety
352 13C NMR Spectra The 13C NMR spectra of the BEFterpolymer ligand and its Zn2+ metal complex are shown in
Bioinorganic Chemistry and Applications 7
(ppm)
12345678910
(a)
(ppm)1 0234567891011
(b)
Figure 4 1H-NMR spectra of (a) BEF ligand and (b) BEFndashZn
200 180 160 140 120 100 80 60 40 20 0(ppm)
(a)
200 180 160 140 120 100 80 60 40 20 0(ppm)
(b)
Figure 5 13C-NMR spectra of (a) BEF ligand and (b) BEFndashZn
O2N S
N
NH NH
M
NHCH2 CH2 CH2 CH2
n
O2NS
NNH NH NHCH2 CH2 CH2 CH2
n
H2OH2O
[M = Cu(II) Ni(II) and Zn(II)]
Figure 6 Proposed geometry of BEF metal complexes
Figure 5 The observed chemical shifts are assigned on thebasis of the literature [22 27]The spectrum of ligand showedthat the corresponding peaks at 1717 1585 1315 1219 14061167 and 1253 ppm are attributed to the aromatic carbonsof the benzothiazole ring The peak appearing at 502 ppmis assigned to the methylenic carbon of NHndashCH
2bridge in
the ligand The spectrum of Zn2+ complex showed the peaksfor aromatic ring in the same region which was appearingin its parent ligand The shifting of the methylene carbonfrom 502 to 561 ppm from its ligand clearly suggests that the
coordination takes place between the nitrogen atoms of theethylenediamine moiety
From the elemental and spectral data (FTIR UV-VisESR and NMR (1H and 13C)) the structure of the BEF ter-polymer ligand and its metal complexes has been confirmedThe proposed geometry of the BEF complexes is shown inFigure 6
36 Surface Analysis The SEM is applied to understandthe surface features of the polymeric materials The SEM
8 Bioinorganic Chemistry and Applications
(a) (b)
(c) (d)
(e)
Figure 7 SEM images of (a) and (b) BEF ligand (c) BEFndashCu (d) BEFndashNi and (e) BEFndashZn
photographs in times1000 and times2000 magnifications for BEFligand and times3000 magnifications for BEF complexes areshown in Figure 7 The white bar at the bottom of the SEMphotographs represents the scale The SEM photographs ofthe BEF terpolymer ligand show leaf like appearance Thescattered structure of the terpolymer establishes a transitionstate between the crystalline and the amorphous phases [28]
Themorphology of BEF terpolymer resin exhibits growthof crystals from polymer solutions corresponding to the
most prominent organization in polymers on a large scalewith spherulites Ideally spherulites are the aggregates ofsubmicroscopic size particles Spherulites are characterizedby secondary structural features such as faint corrugationsThe SEM photographs of polymers have an appreciableamorphous fraction with a small amount of shallow pitsThe surface of BEF metal complexes contributes to greatersegments of crystalline regions compared to their parentligand which may arise from the contraction of the voids by
Bioinorganic Chemistry and Applications 9
Inte
nsity
(au
)
0 20 40 60 802120579
(a)
Inte
nsity
(au
)
0 20 40 60 802120579
(b)
Inte
nsity
(au
)
0 20 40 60 802120579
(c)
Inte
nsity
(au
)
0 20 40 60 802120579
(d)
Figure 8 XRD patterns of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
the cooperative contribution of the ligand for complexationwith metal ions or the disappearance of the voids in therearrangement of polymer chains for complexation withmetal ions This is a further evidence for the complexationof BEF terpolymer with metal ions
37 XRD Studies X-ray diffraction (XRD) patterns of BEFand its metal complexes are shown in Figure 8 It provides adetailed comparative account of the behavior of the terpoly-mer and itsmetal complexesThepattern of BEF ligand showsthe main characteristic peak and broad shoulder In view ofthe relative half value width it may be concluded that thepolymer is partially crystalline and the broad characteristicpeak indicates the amorphous nature of the terpolymerTherefore the BEF terpolymer has transition state betweenamorphous state and crystalline state whereas its metalchelates possess crystalline nature The enhanced crystallinebehavior of the BEF complexes may be due to the insertion ofmetal ions with their parent ligand [29]
38 Thermal Stability Thermal stability of the BEF terpoly-mer and its metal complexes was analyzed by thermogravi-metric analysis (TGA) The thermograms of the terpolymer
and its metal complexes are shown in Figure 9 and their per-centages of weight loss at various temperatures are presentedin Table 4
381Thermal Stability of BEF Terpolymer From the thermo-gram of BEF terpolymer there were three stages of degra-dation (200ndash320∘C 320ndash580∘C and 580ndash835∘C) observedThe first stage of degradation was observed between 200∘Cand 320∘C (found 5883 calc 5794) which reveals thedegradation of the benzothiazole ring The second stageof degradation begins at 320∘C and ends at 580∘C (found1003 calc 0931) which may be due to the eliminationof cross-linkages The third and final stage of degradation isobserved above 580∘C and continued up to 825∘C (found2506 calc 2473) which can be attributed to the weightloss of aliphatic group (ethylenediamine moiety) from theBEF terpolymer
382 Thermal Stability of BEF Metal Complexes In generalthe water of hydration may be considered as either crystalwater molecules or coordination water molecules Accordingto Nikolaev et al [30] water eliminated below 150∘C can beconsidered as crystal or lattice water and water eliminated
10 Bioinorganic Chemistry and Applications
Table 4 TGA data for thermal stability
Compound Percentage of weight loss at various temperatures11987950
lowast (∘C) 119879maxlowastlowast (∘C)
100 200 300 400 500 600 700 800 (∘C)BEF ligand 0153 0365 4414 6236 6718 7140 8224 9442 310 825BEFminusCu 0194 1432 3180 4301 4996 5549 6686 8122 500 860BEFminusNi 0893 1660 3735 4935 6460 8767 mdash mdash 405 650BEFminusZn 1464 2262 3833 4616 5726 6492 7614 9129 425 830lowastTemperature of 50 weight loss lowastlowastmaximum decomposition temperature
80
60
40
20
0
0
(a)(b)
(c)(d)
200 400 600 800 1000
100
Wei
ght (
)
Temperature (∘C)
Figure 9 TGA of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d)BEFndashZn
above 150∘C may be due to its coordination to the metalatom present in chelates In the present study in the case ofBEFndashCu2+ Ni2+ and Zn2+ complexes the removal of waterfrom the complex was completed within 150∘C These watermolecules are probably crystal or lattice water moleculesTheremoval of water molecules observed in the range of 150ndash200∘C (found 559ndash608 calc 545ndash551) of all the metalchelates is due to the elimination of two coordinated watermolecules These observations further confirm the distortedoctahedral geometry of BEF metal complexes
The thermogravimetric curves of all the BEF metalchelates showed two degradation steps after loss of watermolecules whichmay indicate that the first step (200ndash600∘C)is faster than the second step (600ndash860∘C) This may bedue to the fact that the noncoordinated part of the liganddecomposes firstwhile the coordinated part decomposes laterand finally it may form the representative metal oxides Theweight of the residues confirms fairly well that ofmetal oxides(found 1247ndash1362 calc 1143ndash1232)
The thermal degradation data of the BEF terpolymerand its metal complexes reveal that the polymeric complexesshow better stability than the BEF terpolymer due to thecoordination of metal ions The order of thermal stability ofthe BEF polymer and its complexes is BEFndashCu2+ gt BEFndashZn2+ gt BEF ligand gt BEFndashNi2+ The greater stability of themetal complexes may be due to the coordination and theenhanced cross linking nature with crowd effect of the metal
complexes [31] In the case of Ni2+ complex the degradationoccurred exceptionally at low temperature compared to theirligand which may be due to the oxidation of polymer by thecatalytic action of the metal ion [32]
383 Thermal Kinetics
(1) Sharp-Wentworth and Freeman-Carroll Method Ther-mal kinetic analysis was performed using Sharp-Wentworthmethod and Freeman-Carroll methods The activationenergy (119864
119886) and order of reaction (119899) plots for BEF terpoly-
mer ligand and its metal complexes by Sharp-Wentworthand Freeman-Carroll methods are shown in Figures 10 11and 12 The expressions used to calculate the kinetic andthermodynamic parameters are presented as follows
(i) Entropy change (Δ119878)
Intercept = log 119870119877
ℎΦ119864119886
+Δ119878
2303119877 (2)
where 119870 = 13806 times 10minus16 ergdegmole 119877 =
1987 caldegmole (8314 JKMol) ℎ = 6625 times
10minus27 erg sec Φ = 0166 Δ119878 = change in entropyand 119864
119886= activation energy from graph
(ii) Free energy change (Δ119865)
Δ119865 = Δ119867 minus 119879Δ119878 (3)
where Δ119867 = enthalpy change = activation energy 119879 =temperature in119870 and Δ119878 = result from (2)
(iii) Frequency factor (119885)
11986123
=log119885119864
119886
119877Φ (4)
11986123
= log 3 + log [1 minus 3radic1 minus 120572] minus log119901 (119909) (5)
where 119885 is the frequency factor 119861 is calculatedfrom (5) log119901(119909) is calculated from Doylersquos tablecorresponding to activation energy and 120572 is degreeof transformation (120572 = 119908119882
119888)
(iv) Apparent entropy (119878lowast)
119878lowast= 2303 log 119885ℎ
119877119879lowast (6)
where119885 is calculated from (4) and 119879lowast is half decom-position temperature
Bioinorganic Chemistry and Applications 11
1000T (Kminus1)
Intercept = minus535
minus45
minus50
minus55
minus60
minus65
minus70
minus75
minus80
10 15 20 25 30
Ea = 952
log[
(dC
dT
)(1
minusC
)]
(a)
minus64
minus62
minus60
minus58
minus56
minus54
minus52
1000T (Kminus1)10 15 20 25 30
Intercept = minus527
Ea = 1297
log[
(dC
dT
)(1
minusC
)]
(b)
minus64
minus62
minus50
minus52
minus54
minus56
minus58
minus60
1000T (Kminus1)10 15 20 25 30
Intercept = minus513
Ea = 693
log[
(dC
dT
)(1
minusC
)]
(c)
minus50
minus51
minus52
minus53
minus54
minus55
minus56
minus57
minus58
minus59
1000T (Kminus1)10 15 20 25 30
Intercept = minus538
Ea = 1108
log[
(dC
dT
)(1
minusC
)]
(d)
Figure 10 Sharp-Wentworth plots of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Table 5 Kinetic and thermodynamic parameters data
CompoundActivation energy
(119864119886kJmolminus1) Entropy change
(Δ119878J)Free energy
change (Δ119865kJ)Frequency
factor (119885sminus1)Apparent
entropy (119878lowastJ)Order of
reaction (119899)lowastSW lowastlowastFC
BEF ligand 952 1039 minus15811 5940 1310 minus2295 090BEFminusCu 1297 1367 minus15425 9079 1205 minus2331 104BEFminusNi 693 460 minus16290 7057 1537 minus2294 093BEFminusZn 1108 1213 minus16001 8013 1243 minus2318 102lowastSW Sharp-Wentworth lowastlowastFC Freeman-Carroll
Further from the knowledge of activation energy cal-culated by Freeman-Carroll method it is possible to eval-uate the values of various thermodynamic parameters Theorder of reaction (119899) and activation energy (119864
119886) and the
thermodynamic parameters such as frequency factor (119885)entropy change (Δ119878) free energy change (Δ119865) and apparententropy (119878lowast) are presented inTable 5The119864
119886values calculated
by SW and FC methods are in good agreement with eachother The order of activation energies for BEF ligand andits Cu2+ Ni2+ and Zn2+ complexes is parallel to the orderof their thermal stability [32] The values of thermodynamic
parameters were comparable indicating a common modeof decomposition reaction The abnormal low values offrequency factor (119885) indicate that the decomposition reactionof BEF terpolymer and its metal complexes can be depictedas a slow reaction The order of reactions (119899) of BEF ligandand its metal complexes is found to be 090 104 093 and102 respectively Hence the BEF terpolymer and its mealcomplexes may be following nearly a first order kinetics
(2) Phadnis-Deshpande Method The activation energiescalculated for BEF ligand and its metal complexes using
12 Bioinorganic Chemistry and Applications
minus00012minus00010minus00008minus00006minus00004minus00002minus00000
26242220181614121008060402
log(dWdt)
(1T)
n = 090
logW
r
logWr
(a)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
20
19
18
17
16
15
14
13
12
11
10
log(dWdt)
(1T)
n = 104
logWr
logW
r
(b)
15
16
17
18
19
14
13
12
11
10
09
log(dWdt)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
(1T)
n = 093logW
r
logWr
(c)
15
16
17
18
14
13
12
11
10
log(dWdt)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
(1T)
n = 102
logW
r
logWr
(d)
Figure 11 Freeman-Carroll plots (119899) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Phadnis-Deshpande method are presented in Table 6 Fromthe 119864
119886values it is possible to propose the degradation
reactionmechanism using PDmethod Further the 119864119886values
calculated by PD method are in good agreement with FCand SW methods Based on the closest 119864
119886values calculated
by PD SW and FC methods the Power law mechanismsuits very well for the BEF ligand and BEFndashCu and BEFndashZn metal complexes However BEFndashNi complex follows theBrounshtein-Ginstling 3-dimensional diffusion mechanism
39 Biological Studies
391 Antibacterial Activity To determine the antibacterialactivity of the BEF terpolymer and its Cu2+ Ni2+ andZn2+ complexes the disc diffusion method was used withamoxicillin as the standard antibiotic The prepared com-pounds were tested against Shigella sonnei Escherichia coliKlebsiella species Staphylococcus aureus Bacillus subtilis andSalmonella typhimuriummicroorganisms
Table 7 contains the screening results corresponding tothe polymeric ligand and its metal complexes with fairinhibition of growth against the tested organisms Shigella
sonnei is a nonmotile non-spore-forming and facultativeanaerobic gram-negative bacterium Shigella bacteria multi-ply within colonic epithelial cells and cause mucosal ulcer-ation inflammation bleeding high fever malaise diarrheaand tenesmus The ligand and its metal complexes showeda reasonable activity against the S sonnei species E coliis an aerobic gram-negative and rod shaped bacteriumInfection of E coli can lead to bloody diarrhea and kidneyfailureThe polymeric ligand and its complexes hold amodestactivity against the E coli Klebsiella is a genus of nonmotileand gram-negative bacteria that infects sites such as nasalpassages liver lung urinary tract bloodstream eye boneand joints It causes a wide range of disease states notablypneumonia septicemia soft tissue infections biliary tractinfection infection of the upper and lower respiratory tractand liver abscess The BEF ligand and its metal complexesshowed a reasonable result against the growth of KlebsiellaStaphylococcus aureus a gram-positive and spherical bac-terium leads to life-threatening diseases like pneumoniaosteomyelitis endocarditis and toxic shock syndrome Toxicshock syndrome is characterized by the sudden onset of highfever vomiting diarrhea and muscle aches followed by lowblood pressure (hypotension) which can lead to shock and
Bioinorganic Chemistry and Applications 13
log[g
(120572)T3]
minus95
minus90
minus85
minus80
minus75
10 15 20 25 30
Intercept = minus825
Ea = 1039
1000T (Kminus1)
(a)
log[g
(120572)T3]
minus78
minus80
minus82
minus84
minus86
minus88
minus90
minus92
minus94
minus96
minus76
Intercept = minus805
Ea = 1367
10 15 20 25 30
1000T (Kminus1)
(b)
log[g
(120572)T3]
minus77
minus78
minus79
minus80
minus81
minus82
minus83
minus84
minus85
minus86
minus87
minus88minus89
Intercept = minus849
Ea = 460
10 15 20 25 30
1000T (Kminus1)
(c)
minus78
minus80
minus82
minus84
minus86
minus7610 15 20 25 30
1000T (Kminus1)
log[g
(120572)T3]
Intercept = minus835
Ea = 1213
(d)
Figure 12 Freeman-Carroll plots (119864119886) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Table 6 Activation energies calculated by Phadnis-Deshpande method
Reaction mechanism model Energy of activation (119864119886) (kJmol)
BEF ligand BEFminusCu BEFminusNi BEFminusZnPower law 60932 62642 59691 54312Power law 121864 125284 119382 108625Phase boundary (contracting sphere) 16497 16816 16174 15009Phase boundary (contracting cylinder) 25894 26436 25383 23466Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 12135 13830 11756 07447
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 08090 09220 07837 04964
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 06067 06915 05878 03723
Valensi 2-dimensional diffusion 168354 171926 165034 152695Jander 3-dimensional diffusion 32995 33632 32349 30018Brounshtein-Ginstling 3-dimensional diffusion 56520 55015 55669 57981The values indicated in bold are closest to the 119864119886 value estimated by FC and SWmethods
14 Bioinorganic Chemistry and Applications
Table 7 Antibacterial activity of BEF ligand and its complexes
Compound Inhibition zone (mm)S sonnei E coli Klebsiella sp S aureus B subtilis S typhi
BEF ligand 15 13 13 14 15 12BEFndashCu 21 17 17 18 18 18BEFndashNi 18 15 18 17 20 15BEFndashZn 16 15 15 16 17 15Standard 26 28 26 25 27 28Control mdash mdash mdash mdash mdash mdashStandard amoxicillin control DMSO
Table 8 Antifungal activity of BEF ligand and its complexes
Compound Inhibition zone (mm)Aspergillus flavus Aspergillus niger Penicillium species Candida albicans Cryptococcus neoformans Mucorspecies
BEF ligand 14 12 12 13 11 12BEFndashCu 20 18 19 18 15 19BEFndashNi 17 14 17 15 13 13BEFndashZn 15 15 18 17 14 16Standard 20 21 19 21 18 22Control mdash mdash mdash mdash mdash mdashStandard fluconazole control DMSO
death There may be a rash resembling sunburn with peelingof skin The ligand and its complexes showed a humbleactivity against the growth of S aureus Bacillus subtilis arerod-shaped and nonpathogenic gram-positive bacteria TheBEF ligand and complexes showed superb activity againstthe growth of this bacterium Salmonella typhimurium is apathogenic gram-negative bacteria predominately found inthe intestinal lumen When the bacterial cells enter epithelialcells lining the intestine they cause host cell ruffling whichtemporarily damages the microvilli on the surface of the cellThis causes a rush of white blood cells into the mucosa andleads to diarrheaThe ligand and its metal complexes showeda moderate activity against the growth of the typhi species
A comparative account on the effect of antibacterialactivity against the chosen microbes indicates that the ligandand its three metal chelates show reasonable activity againstShigella sonnei (15 21 18 and 16mm) and Bacillus subtilis (1518 20 and 17mm) while the growth of other organisms ismoderately inhibited by the BEF ligand and its Cu2+ Ni2+and Zn2+ chelates The highest antibacterial action (21mm)has been observed for BEFndashCu2+ complex against Shigellasonnei
392 Antifungal Activity The antifungal activity of the BEFligand and its metal complexes has also given interestingresults and the growth inhibitions against the chosen fungalstrains are tabulated in Table 8 All the complexes and theirligand have an excellent activity against Aspergillus flavusa mold type fungal strain which may invade arteries of thelung or brain to cause infections and also produce a toxinAspergillus niger is one of the most common causes for
otomycosis The chelates and the ligand are found to havea reasonable activity for A niger Penicillium species causesinfection in humans and the resulting disease is known gener-ically as penicilliosis The ligand and the metal complexeshave wonderful activity against this species Further BEFndashCucomplex has a superior activity compared to the rest of othercomplexes Candida albicans is a diploid fungus and a causalagent of opportunistic oral and genital infections in humansand also emerged as an important cause of morbidity andmortality in immunocompromised patients The BEF ligandand its chelates possess a modest activity against C albicansover and above the standard Cryptococcus neoformans is anencapsulated yeast-like fungus that can live in both plantsand animals and cause lung infection The terpolymer ligandand its chelates have a fair activity against this fungal strainThe chelate compounds and the ligand havemoderate activityagainst Mucor species a filamentous fungus which causesseptic arthritis renal infections and pulmonary infections
From the antimicrobial results themetal complexes showhigher activity than their ligand which may be stronglydependent on the central metal ions and coordination num-bers metal chelates The higher activity due to the metal ionsshared with the donor atoms (N and S) of the thiazole ring ispresent in the ligand and the 120587-electron delocalization overthe chelate ring This effect increases the lipophilic characterof the metal ion which favors the permeation through thelipoid layers of the bacterial and fungal membranes [33 34]It is perceived that the factors such as solubility conductivitydipole moment and cell permeability may also contributeto the increased activity of the complexes [35 36] Fromthe results of the studies at 500 ppm concentration thecompounds establish better antimicrobial activity Hence it
Bioinorganic Chemistry and Applications 15
is an interesting result that a very low concentration of thecompound namely 500 ppm is enough to bring out aneffective inhibition against the chosen microbes
4 Conclusion
The synthesized 2-amino-6-nitro-benzothiazole-ethylene-diamine-formaldehyde terpolymer has acted as a ligandsuccessfully to form metal complexes The synthesized com-pounds were well characterized by various spectral andphysical analyses The morphological features suggest thatthe complexes are slightly more crystalline in nature thantheir parent ligandThe antibacterial and antifungal activitiesreveal that the terpolymer and its metal complexes can beactive against the selected bacterial and fungal strains Nearlyall of the compoundsmay suit well for drug delivery field afterchecking for their toxicology behaviour in thorough mannerThermal studies are also helpful to realize the standing capac-ity of the compounds which survive as antimicrobial coatingmaterials in various environmental conditions Because ofthe proven high stability nature and microbial preventioncapacity the BEF terpolymer and its Cu2+ Ni2+ and Zn2+complexes hold inadequate applications in biological fieldThe thermal stability of the terpolymer and its metal com-plexes was found greater From the thermodynamic andkinetic studies the abnormal low values of frequency factor(119885) indicate that the thermal decomposition reaction of BEFterpolymer and its metal complexes can be depicted as a slowreaction The BEF terpolymer and its metal complexes maybe following nearly a first order kinetics
Conflict of Interests
The authors certify that there is no conflict of interests withany financial organization regarding thematerial discussed inthe paper
Acknowledgments
The authors thank the Management and Principal ofOxford Engineering College Tiruchirappalli CoimbatoreInstitute of Technology Coimbatore Jamal Mohamed Col-lege (Autonomous) Tiruchirappalli Tamil Nadu and DrD Jeyakumar Scientist Central Electrochemical ResearchInstitute (CECRI-CSIR) Karaikudi Tamil Nadu for theirsupport and encouragement
References
[1] C U Pittman K S Ramachandran Jr and K R LowyerldquoSynthesis of fungicidal monomers polymers and latticesrdquoJournal of Coating Technology vol 54 pp 27ndash40 1982
[2] M N Patel J R Patel and D H Sutaria ldquoNovel co-ordinationpolychelatesrdquo Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry vol 24 no 8 pp 1297ndash1309 1994
[3] V V Ukey and H D Juneja ldquoSynthetic and spectroscopicstudies of chelate polymers involving azelaoyl bis-N-phenylhydroxamic acid with transition metal ionsrdquo Journal of AppliedPolymer Science vol 99 no 1 pp 273ndash278 2006
[4] S K-H Thiele and D R Wilson ldquoAlternate transition metalcomplex based diene polymerizationrdquo Polymer Reviews vol 43no 4 pp 581ndash628 2003
[5] N Nishat S Ahmad and T Ahamad ldquoSynthesis and character-ization of antibacterial polychelates of urea-formaldehyde resinwith Cr(III) Mn(II) Fe(III) Co(II) Ni(II) Cu(II) and Zn(II)metal ionsrdquo Journal of Applied Polymer Science vol 100 no 2pp 928ndash936 2006
[6] E Brzezinska G Koska and K Walczynski ldquoApplicationof thin-layer chromatographic data in quantitative structure-activity relationship assay of thiazole and benzothiazole deriva-tives with Hmdashantihistamine activityrdquo Journal of Chromatogra-phy A vol 1007 pp 145ndash155 2003
[7] M A R Ahamed and A R Burkanudeen ldquoMetal complexesof a novel terpolymer ligand synthesis spectral morphologythermal degradation kinetics and antimicrobial screeningrdquoJournal of Inorganic andOrganometallic Polymers andMaterialsvol 22 no 5 pp 1046ndash1061 2012
[8] B S Holla K V Malini V S Rao B K Sarojini and N SKumari ldquoSynthesis of some new 24-disubstituted thiazoles aspossible antibacterial and anti-inflammatory agentsrdquo EuropeanJournal of Medicinal Chemistry vol 38 no 3 pp 313ndash318 2003
[9] O I El-Sabbagh M M Baraka S M Ibrahim et al ldquoSynthesisand antiviral activity of new pyrazole and thiazole derivativesrdquoEuropean Journal of Medicinal Chemistry vol 44 no 9 pp3746ndash3753 2009
[10] A Andreani M Granaiola A Leoni A Locatelli R Morigiand M Rambaldi ldquoSynthesis and antitubercular activity ofimidazo[21-b]thiazolesrdquo European Journal of Medicinal Chem-istry vol 36 no 9 pp 743ndash746 2001
[11] E Yousif Y Farina K Kasar A Graisa and K Ayid ldquoCom-plexes of 2-thioacetic acid benzothiazole with somemetal ionsrdquoAmerican Journal of Applied Sciences vol 6 no 4 pp 582ndash5852009
[12] B P Mallikarjuna B S Sastry G V Suresh Kumar Y Rajen-draprasad S M Chandrashekar and K Sathisha ldquoSynthesis ofnew 4-isopropylthiazole hydrazide analogs and some derivedclubbed triazole oxadiazole ring systemsmdasha novel class ofpotential antibacterial antifungal and antitubercular agentsrdquoEuropean Journal of Medicinal Chemistry vol 44 pp 4739ndash4746 2009
[13] T Ahamad V Kumar and N Nishat ldquoNew class of anti-microbial agents synthesis characterization and anti-microbial activities of metal chelated polyureardquo Journal ofBiomedical Materials Research A vol 88 no 2 pp 288ndash2942009
[14] M V Patel J N Patel M B Dolia and R M Patel ldquoPolyether-ketones synthesis characterization and antimicrobial activityrdquoInternational Journal of Polymeric Materials and PolymericBiomaterials vol 54 no 11 pp 1059ndash1071 2005
[15] K R Alagawadi and S G Alegaon ldquoSynthesis characteriza-tion and antimicrobial activity evaluation of new 24-Thiazoli-dinediones bearing imidazo[21-b][134]thiadiazole moietyrdquoArabian Journal of Chemistry vol 4 no 4 pp 465ndash472 2011
[16] M Ashok B S Holla and N S Kumari ldquoConvenientone pot synthesis of some novel derivatives of thiazolo[23-b]dihydropyrimidinone possessing 4-methylthiophenyl moietyand evaluation of their antibacterial and antifungal activitiesrdquoEuropean Journal ofMedicinal Chemistry vol 42 no 3 pp 380ndash385 2007
16 Bioinorganic Chemistry and Applications
[17] T Ahamad V Kumar S Parveen and N Nishat ldquoIn vitroantibacterial and antifungal assay of poly-(ethylene oxamide-NN1015840-diacetate) and its polymer-metal complexesrdquo AppliedOrganometallic Chemistry vol 21 no 12 pp 1013ndash1021 2007
[18] R S Azarudeen M A R Ahamed and A R BurkanudeenldquoBiological and thermal investigations of polychelates derivedfrom a novel terpolymer ligandrdquo Journal of Polymer Researchvol 18 no 6 pp 1331ndash1341 2011
[19] R S Azarudeen and A R Burkanudeen ldquoSynthesis spectralmorphology thermal degradation kinetics and antibacterialstudies of terpolymermetal complexesrdquo Journal of Inorganic andOrganometallic Polymers and Materials vol 22 no 4 pp 791ndash806 2012
[20] R S Azarudeen and A R Burkanudeen ldquoStudies of newoligomer-metal complexes and their antibacterial activitiesrdquoPolymer International vol 62 no 3 pp 362ndash374 2013
[21] G S Devi A K Muthu D S Kumar S Rekha R Indhumathiand R Nandhini ldquoStudies on the antibacterial and antifungalactivities of the ethanolic extracts of Luffa cylindrica (Linn)fruitrdquo International Journal of Drug Development and Researchvol 1 pp 105ndash109 2013
[22] R M Silverstein and G C Bassler Spectrometric IdentificationofOrganic Compounds JohnWileyamp SonsNewYorkNYUSA2nd edition 1967
[23] Y-G Zhao H-Y Shen S-D Pan and M-Q Hu ldquoSyn-thesis characterization and properties of ethylenediamine-functionalized Fe
3O4magnetic polymers for removal of Cr(VI)
in wastewaterrdquo Journal of Hazardous Materials vol 182 no 1-3pp 295ndash302 2010
[24] Y R Sharma Elementary Organic Absorption Spectroscopy SChand amp Co Ltd New Delhi India 1980
[25] D Kivelson and R Neiman ldquoESR line shapes in glasses ofcopper complexesrdquoThe Journal of Chemical Physics vol 35 no1 pp 149ndash155 1961
[26] E Pretsch P Buhlmann and C Afflolter Structure Determi-nation of Organic Compounds Springer New York NY USA2000
[27] J L White Modern Magnetic Resonance Kluwer AcademicPress London UK 2006
[28] M M Patel M A Kapadia and J D Joshi ldquoThermal andcatalytic aspects of Ln(III) polymer-metal complexesrdquo PolymerInternational vol 58 no 7 pp 728ndash737 2009
[29] S Nanjundan C S J Selvamalar and R Jayakumar ldquoSynthesisand characterization of poly(3-acetyl-4-hydroxyphenyl acry-late) and its Cu(II) and Ni(II) complexesrdquo European PolymerJournal vol 40 no 10 pp 2313ndash2321 2004
[30] A V Nikolaev V A Logvinenco and L I Myachina ThermalAnalysis Academic Press New York NY USA 1969
[31] A Z El-Sonbati and M A Hefni ldquoPolymer complexes PartXXVImdashNovel mixed ligand poly-(5-vinyl salicylidene)-12-diaminobenzene complexesrdquo Polymer Degradation and Stabil-ity vol 43 no 1 pp 33ndash42 1994
[32] A S Aswar and N S Bhave ldquoThermal degradation studies ofsome new coordination polymersrdquo Polymer Degradation andStability vol 31 no 1 pp 115ndash124 1991
[33] T Ahamad V Kumar and N Nishat ldquoSynthesis characteri-zation and antimicrobial activity of transition metal chelatedthiourea-formaldehyde resinrdquo Polymer International vol 55no 12 pp 1398ndash1406 2006
[34] M M Patel M A Kapadia G P Patel and J D Joshi ldquoSynthe-sis characterization ion-exchange and antimicrobial study of
poly[(2-hydroxy-4-methoxybenzophenone) propylene] resinand its polychelates with lanthanides (III)rdquo Journal of AppliedPolymer Science vol 106 no 2 pp 1307ndash1317 2007
[35] M A Neelakantan S S Marriappan J Dharmaraja T Jeyaku-mar and K Muthukumaran ldquoSpectral XRD SEM and bio-logical activities of transition metal complexes of polydentateligands containing thiazole moietyrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 71 no 2 pp 628ndash635 2008
[36] G B Bagihalli S A Patil and P S Badami ldquoSynthesisphysicochemical investigation and biological studies of zinc(II)complexes with 124-triazole schiff basesrdquo Journal of the IranianChemical Society vol 6 no 2 pp 259ndash270 2009
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Inorganic ChemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Carbohydrate Chemistry
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
Physical Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom
Analytical Methods in Chemistry
Journal of
Volume 2014
Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
SpectroscopyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Medicinal ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chromatography Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Applied ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Theoretical ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Spectroscopy
Analytical ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Quantum Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Organic Chemistry International
ElectrochemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CatalystsJournal of
6 Bioinorganic Chemistry and Applications
Table 3 UV-Visible ESR data and magnetic moments
Compound Transitions (cmminus1) Assignments Geometry ESR Magnetic moment (BM)119892II 119892
perp
BEF 260 nm 120587 rarr 120587lowast mdash mdash mdash mdash370 nm 119899 rarr 120587
lowast
BEFndashCu14295 1
119861119892rarr
2119864119892
Octahedral 221 211 18516465 1119861119892rarr
2119864119892
24580 Charge transfer
BEFndashNi12474 3119879
2119892(119865) larr 3119860
2119892(119865)
Octahedral mdash mdash 30514642 31198791119892(119865) larr 3119860
2119892(119865)
24370 31198791119892(119875) larr 3119860
2119892(119865)
BEFndashZn mdash mdash Octahedral mdash mdash Diamagnetic
0 1000
Inte
nsity
2000 3000 4000 5000 6000 7000G
Figure 3 ESR spectra of BEFndashCu complex
of aromatic nucleus and 119899 rarr 120587lowast transition indicates thepresence of ndashNH groups The electronic spectrum of BEFndashCu metal complex exhibited bands at 14295 16465 and24580 cmminus1 and the assignments are 1119861
119892rarr2119864119892 1119861119892
rarr2119864119892 and charge transfer spectra which lead to a distorted
octahedral geometry with the magnetic moment of 185 BMThe electronic spectrum of BEFndashNi exhibits three bands at12474 14642 and 24370 cmminus1 assigned to the spin allowedtransitions 3119879
2119892(119865) larr 3119860
2119892(119865) 3119879
1119892(119865) larr 3119860
2119892(119865) and
31198791119892(119875) larr 3
1198602119892(119865) in an octahedral environment with a
magnetic moment of 305 BMThe diamagnetic nature of theBEFndashZn is also confirmed with octahedral geometry Basedon the literature the geometry is assigned to all the metalcomplexes [24]
The ESR spectrum of BEFndashCu complex is shown inFigure 3 and its spectral data are presented in Table 3 Thespectrum provides useful information about the metal ionenvironment in the respective complexes The ESR spectrumof BEFndashCu metal complex showed that 119892
= 221 and
119892perp= 211 lead to an octahedral environment According to
Kivelson and Neimen [25] the bond between the ligand andthe metal possesses a more covalent character than ionic In
general both the parallel and the perpendicular 119892 values canbe used to calculate the 119866 value by the following equation
119866 =119892minus 2002
119892perpminus 2002
(1)
Using the above equation the 119866 value for BEFndashCu was192 which clearly indicates that the complex forms with astrong field ligand
35 Nuclear Magnetic Resonance The NMR (1H and 13C)spectra for BEF terpolymer ligand and its zinc metal complex(due to d9 and d8 configurations both NMR spectra forcopper and nickel metal complexes are complicated) wererecorded to elucidate the structure of the ligand and itscomplex
351 1H NMR Spectra The 1H NMR spectra of BEF ter-polymer ligand and its Zn2+ metal complex are shownin Figure 4 The signals obtained for the terpolymer andits metal complexes were interpreted on the basis of thedata available in the literature [22 26] The spectrum ofterpolymer showed that the signals appearing in the region of739ndash824 ppm are assigned to all the protons of the aromaticring A peak appearing at 250 is assigned to the methyleneprotons of the terpolymer ligand The terpolymer spectrumshowed a signal appearing at 472 ppm that is assigned tothe ndashNH protons of ethylenediamine moiety and the peakappearing at 865 ppm is assigned to ndashNH proton of thiazolering A weak signal appearing at 302 ppmmay be assigned toethylenic protons of an ArndashCH
2ndashNHndashCH
2moiety
The spectrum of the Zn2+ complex showed multiplet inthe range of 740ndash824 ppm is assigned to the aromatic protonsand the methylene protons appeared at 215ndash250 ppm Thesignal obtained at 508 ppm is assigned to ndashNH protons ofethylenediamine and this shift from its ligand gives a clearevidence for the complexation of the ligand with the metalions through the lone pair of nitrogen of ethylenediaminemoiety
352 13C NMR Spectra The 13C NMR spectra of the BEFterpolymer ligand and its Zn2+ metal complex are shown in
Bioinorganic Chemistry and Applications 7
(ppm)
12345678910
(a)
(ppm)1 0234567891011
(b)
Figure 4 1H-NMR spectra of (a) BEF ligand and (b) BEFndashZn
200 180 160 140 120 100 80 60 40 20 0(ppm)
(a)
200 180 160 140 120 100 80 60 40 20 0(ppm)
(b)
Figure 5 13C-NMR spectra of (a) BEF ligand and (b) BEFndashZn
O2N S
N
NH NH
M
NHCH2 CH2 CH2 CH2
n
O2NS
NNH NH NHCH2 CH2 CH2 CH2
n
H2OH2O
[M = Cu(II) Ni(II) and Zn(II)]
Figure 6 Proposed geometry of BEF metal complexes
Figure 5 The observed chemical shifts are assigned on thebasis of the literature [22 27]The spectrum of ligand showedthat the corresponding peaks at 1717 1585 1315 1219 14061167 and 1253 ppm are attributed to the aromatic carbonsof the benzothiazole ring The peak appearing at 502 ppmis assigned to the methylenic carbon of NHndashCH
2bridge in
the ligand The spectrum of Zn2+ complex showed the peaksfor aromatic ring in the same region which was appearingin its parent ligand The shifting of the methylene carbonfrom 502 to 561 ppm from its ligand clearly suggests that the
coordination takes place between the nitrogen atoms of theethylenediamine moiety
From the elemental and spectral data (FTIR UV-VisESR and NMR (1H and 13C)) the structure of the BEF ter-polymer ligand and its metal complexes has been confirmedThe proposed geometry of the BEF complexes is shown inFigure 6
36 Surface Analysis The SEM is applied to understandthe surface features of the polymeric materials The SEM
8 Bioinorganic Chemistry and Applications
(a) (b)
(c) (d)
(e)
Figure 7 SEM images of (a) and (b) BEF ligand (c) BEFndashCu (d) BEFndashNi and (e) BEFndashZn
photographs in times1000 and times2000 magnifications for BEFligand and times3000 magnifications for BEF complexes areshown in Figure 7 The white bar at the bottom of the SEMphotographs represents the scale The SEM photographs ofthe BEF terpolymer ligand show leaf like appearance Thescattered structure of the terpolymer establishes a transitionstate between the crystalline and the amorphous phases [28]
Themorphology of BEF terpolymer resin exhibits growthof crystals from polymer solutions corresponding to the
most prominent organization in polymers on a large scalewith spherulites Ideally spherulites are the aggregates ofsubmicroscopic size particles Spherulites are characterizedby secondary structural features such as faint corrugationsThe SEM photographs of polymers have an appreciableamorphous fraction with a small amount of shallow pitsThe surface of BEF metal complexes contributes to greatersegments of crystalline regions compared to their parentligand which may arise from the contraction of the voids by
Bioinorganic Chemistry and Applications 9
Inte
nsity
(au
)
0 20 40 60 802120579
(a)
Inte
nsity
(au
)
0 20 40 60 802120579
(b)
Inte
nsity
(au
)
0 20 40 60 802120579
(c)
Inte
nsity
(au
)
0 20 40 60 802120579
(d)
Figure 8 XRD patterns of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
the cooperative contribution of the ligand for complexationwith metal ions or the disappearance of the voids in therearrangement of polymer chains for complexation withmetal ions This is a further evidence for the complexationof BEF terpolymer with metal ions
37 XRD Studies X-ray diffraction (XRD) patterns of BEFand its metal complexes are shown in Figure 8 It provides adetailed comparative account of the behavior of the terpoly-mer and itsmetal complexesThepattern of BEF ligand showsthe main characteristic peak and broad shoulder In view ofthe relative half value width it may be concluded that thepolymer is partially crystalline and the broad characteristicpeak indicates the amorphous nature of the terpolymerTherefore the BEF terpolymer has transition state betweenamorphous state and crystalline state whereas its metalchelates possess crystalline nature The enhanced crystallinebehavior of the BEF complexes may be due to the insertion ofmetal ions with their parent ligand [29]
38 Thermal Stability Thermal stability of the BEF terpoly-mer and its metal complexes was analyzed by thermogravi-metric analysis (TGA) The thermograms of the terpolymer
and its metal complexes are shown in Figure 9 and their per-centages of weight loss at various temperatures are presentedin Table 4
381Thermal Stability of BEF Terpolymer From the thermo-gram of BEF terpolymer there were three stages of degra-dation (200ndash320∘C 320ndash580∘C and 580ndash835∘C) observedThe first stage of degradation was observed between 200∘Cand 320∘C (found 5883 calc 5794) which reveals thedegradation of the benzothiazole ring The second stageof degradation begins at 320∘C and ends at 580∘C (found1003 calc 0931) which may be due to the eliminationof cross-linkages The third and final stage of degradation isobserved above 580∘C and continued up to 825∘C (found2506 calc 2473) which can be attributed to the weightloss of aliphatic group (ethylenediamine moiety) from theBEF terpolymer
382 Thermal Stability of BEF Metal Complexes In generalthe water of hydration may be considered as either crystalwater molecules or coordination water molecules Accordingto Nikolaev et al [30] water eliminated below 150∘C can beconsidered as crystal or lattice water and water eliminated
10 Bioinorganic Chemistry and Applications
Table 4 TGA data for thermal stability
Compound Percentage of weight loss at various temperatures11987950
lowast (∘C) 119879maxlowastlowast (∘C)
100 200 300 400 500 600 700 800 (∘C)BEF ligand 0153 0365 4414 6236 6718 7140 8224 9442 310 825BEFminusCu 0194 1432 3180 4301 4996 5549 6686 8122 500 860BEFminusNi 0893 1660 3735 4935 6460 8767 mdash mdash 405 650BEFminusZn 1464 2262 3833 4616 5726 6492 7614 9129 425 830lowastTemperature of 50 weight loss lowastlowastmaximum decomposition temperature
80
60
40
20
0
0
(a)(b)
(c)(d)
200 400 600 800 1000
100
Wei
ght (
)
Temperature (∘C)
Figure 9 TGA of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d)BEFndashZn
above 150∘C may be due to its coordination to the metalatom present in chelates In the present study in the case ofBEFndashCu2+ Ni2+ and Zn2+ complexes the removal of waterfrom the complex was completed within 150∘C These watermolecules are probably crystal or lattice water moleculesTheremoval of water molecules observed in the range of 150ndash200∘C (found 559ndash608 calc 545ndash551) of all the metalchelates is due to the elimination of two coordinated watermolecules These observations further confirm the distortedoctahedral geometry of BEF metal complexes
The thermogravimetric curves of all the BEF metalchelates showed two degradation steps after loss of watermolecules whichmay indicate that the first step (200ndash600∘C)is faster than the second step (600ndash860∘C) This may bedue to the fact that the noncoordinated part of the liganddecomposes firstwhile the coordinated part decomposes laterand finally it may form the representative metal oxides Theweight of the residues confirms fairly well that ofmetal oxides(found 1247ndash1362 calc 1143ndash1232)
The thermal degradation data of the BEF terpolymerand its metal complexes reveal that the polymeric complexesshow better stability than the BEF terpolymer due to thecoordination of metal ions The order of thermal stability ofthe BEF polymer and its complexes is BEFndashCu2+ gt BEFndashZn2+ gt BEF ligand gt BEFndashNi2+ The greater stability of themetal complexes may be due to the coordination and theenhanced cross linking nature with crowd effect of the metal
complexes [31] In the case of Ni2+ complex the degradationoccurred exceptionally at low temperature compared to theirligand which may be due to the oxidation of polymer by thecatalytic action of the metal ion [32]
383 Thermal Kinetics
(1) Sharp-Wentworth and Freeman-Carroll Method Ther-mal kinetic analysis was performed using Sharp-Wentworthmethod and Freeman-Carroll methods The activationenergy (119864
119886) and order of reaction (119899) plots for BEF terpoly-
mer ligand and its metal complexes by Sharp-Wentworthand Freeman-Carroll methods are shown in Figures 10 11and 12 The expressions used to calculate the kinetic andthermodynamic parameters are presented as follows
(i) Entropy change (Δ119878)
Intercept = log 119870119877
ℎΦ119864119886
+Δ119878
2303119877 (2)
where 119870 = 13806 times 10minus16 ergdegmole 119877 =
1987 caldegmole (8314 JKMol) ℎ = 6625 times
10minus27 erg sec Φ = 0166 Δ119878 = change in entropyand 119864
119886= activation energy from graph
(ii) Free energy change (Δ119865)
Δ119865 = Δ119867 minus 119879Δ119878 (3)
where Δ119867 = enthalpy change = activation energy 119879 =temperature in119870 and Δ119878 = result from (2)
(iii) Frequency factor (119885)
11986123
=log119885119864
119886
119877Φ (4)
11986123
= log 3 + log [1 minus 3radic1 minus 120572] minus log119901 (119909) (5)
where 119885 is the frequency factor 119861 is calculatedfrom (5) log119901(119909) is calculated from Doylersquos tablecorresponding to activation energy and 120572 is degreeof transformation (120572 = 119908119882
119888)
(iv) Apparent entropy (119878lowast)
119878lowast= 2303 log 119885ℎ
119877119879lowast (6)
where119885 is calculated from (4) and 119879lowast is half decom-position temperature
Bioinorganic Chemistry and Applications 11
1000T (Kminus1)
Intercept = minus535
minus45
minus50
minus55
minus60
minus65
minus70
minus75
minus80
10 15 20 25 30
Ea = 952
log[
(dC
dT
)(1
minusC
)]
(a)
minus64
minus62
minus60
minus58
minus56
minus54
minus52
1000T (Kminus1)10 15 20 25 30
Intercept = minus527
Ea = 1297
log[
(dC
dT
)(1
minusC
)]
(b)
minus64
minus62
minus50
minus52
minus54
minus56
minus58
minus60
1000T (Kminus1)10 15 20 25 30
Intercept = minus513
Ea = 693
log[
(dC
dT
)(1
minusC
)]
(c)
minus50
minus51
minus52
minus53
minus54
minus55
minus56
minus57
minus58
minus59
1000T (Kminus1)10 15 20 25 30
Intercept = minus538
Ea = 1108
log[
(dC
dT
)(1
minusC
)]
(d)
Figure 10 Sharp-Wentworth plots of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Table 5 Kinetic and thermodynamic parameters data
CompoundActivation energy
(119864119886kJmolminus1) Entropy change
(Δ119878J)Free energy
change (Δ119865kJ)Frequency
factor (119885sminus1)Apparent
entropy (119878lowastJ)Order of
reaction (119899)lowastSW lowastlowastFC
BEF ligand 952 1039 minus15811 5940 1310 minus2295 090BEFminusCu 1297 1367 minus15425 9079 1205 minus2331 104BEFminusNi 693 460 minus16290 7057 1537 minus2294 093BEFminusZn 1108 1213 minus16001 8013 1243 minus2318 102lowastSW Sharp-Wentworth lowastlowastFC Freeman-Carroll
Further from the knowledge of activation energy cal-culated by Freeman-Carroll method it is possible to eval-uate the values of various thermodynamic parameters Theorder of reaction (119899) and activation energy (119864
119886) and the
thermodynamic parameters such as frequency factor (119885)entropy change (Δ119878) free energy change (Δ119865) and apparententropy (119878lowast) are presented inTable 5The119864
119886values calculated
by SW and FC methods are in good agreement with eachother The order of activation energies for BEF ligand andits Cu2+ Ni2+ and Zn2+ complexes is parallel to the orderof their thermal stability [32] The values of thermodynamic
parameters were comparable indicating a common modeof decomposition reaction The abnormal low values offrequency factor (119885) indicate that the decomposition reactionof BEF terpolymer and its metal complexes can be depictedas a slow reaction The order of reactions (119899) of BEF ligandand its metal complexes is found to be 090 104 093 and102 respectively Hence the BEF terpolymer and its mealcomplexes may be following nearly a first order kinetics
(2) Phadnis-Deshpande Method The activation energiescalculated for BEF ligand and its metal complexes using
12 Bioinorganic Chemistry and Applications
minus00012minus00010minus00008minus00006minus00004minus00002minus00000
26242220181614121008060402
log(dWdt)
(1T)
n = 090
logW
r
logWr
(a)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
20
19
18
17
16
15
14
13
12
11
10
log(dWdt)
(1T)
n = 104
logWr
logW
r
(b)
15
16
17
18
19
14
13
12
11
10
09
log(dWdt)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
(1T)
n = 093logW
r
logWr
(c)
15
16
17
18
14
13
12
11
10
log(dWdt)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
(1T)
n = 102
logW
r
logWr
(d)
Figure 11 Freeman-Carroll plots (119899) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Phadnis-Deshpande method are presented in Table 6 Fromthe 119864
119886values it is possible to propose the degradation
reactionmechanism using PDmethod Further the 119864119886values
calculated by PD method are in good agreement with FCand SW methods Based on the closest 119864
119886values calculated
by PD SW and FC methods the Power law mechanismsuits very well for the BEF ligand and BEFndashCu and BEFndashZn metal complexes However BEFndashNi complex follows theBrounshtein-Ginstling 3-dimensional diffusion mechanism
39 Biological Studies
391 Antibacterial Activity To determine the antibacterialactivity of the BEF terpolymer and its Cu2+ Ni2+ andZn2+ complexes the disc diffusion method was used withamoxicillin as the standard antibiotic The prepared com-pounds were tested against Shigella sonnei Escherichia coliKlebsiella species Staphylococcus aureus Bacillus subtilis andSalmonella typhimuriummicroorganisms
Table 7 contains the screening results corresponding tothe polymeric ligand and its metal complexes with fairinhibition of growth against the tested organisms Shigella
sonnei is a nonmotile non-spore-forming and facultativeanaerobic gram-negative bacterium Shigella bacteria multi-ply within colonic epithelial cells and cause mucosal ulcer-ation inflammation bleeding high fever malaise diarrheaand tenesmus The ligand and its metal complexes showeda reasonable activity against the S sonnei species E coliis an aerobic gram-negative and rod shaped bacteriumInfection of E coli can lead to bloody diarrhea and kidneyfailureThe polymeric ligand and its complexes hold amodestactivity against the E coli Klebsiella is a genus of nonmotileand gram-negative bacteria that infects sites such as nasalpassages liver lung urinary tract bloodstream eye boneand joints It causes a wide range of disease states notablypneumonia septicemia soft tissue infections biliary tractinfection infection of the upper and lower respiratory tractand liver abscess The BEF ligand and its metal complexesshowed a reasonable result against the growth of KlebsiellaStaphylococcus aureus a gram-positive and spherical bac-terium leads to life-threatening diseases like pneumoniaosteomyelitis endocarditis and toxic shock syndrome Toxicshock syndrome is characterized by the sudden onset of highfever vomiting diarrhea and muscle aches followed by lowblood pressure (hypotension) which can lead to shock and
Bioinorganic Chemistry and Applications 13
log[g
(120572)T3]
minus95
minus90
minus85
minus80
minus75
10 15 20 25 30
Intercept = minus825
Ea = 1039
1000T (Kminus1)
(a)
log[g
(120572)T3]
minus78
minus80
minus82
minus84
minus86
minus88
minus90
minus92
minus94
minus96
minus76
Intercept = minus805
Ea = 1367
10 15 20 25 30
1000T (Kminus1)
(b)
log[g
(120572)T3]
minus77
minus78
minus79
minus80
minus81
minus82
minus83
minus84
minus85
minus86
minus87
minus88minus89
Intercept = minus849
Ea = 460
10 15 20 25 30
1000T (Kminus1)
(c)
minus78
minus80
minus82
minus84
minus86
minus7610 15 20 25 30
1000T (Kminus1)
log[g
(120572)T3]
Intercept = minus835
Ea = 1213
(d)
Figure 12 Freeman-Carroll plots (119864119886) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Table 6 Activation energies calculated by Phadnis-Deshpande method
Reaction mechanism model Energy of activation (119864119886) (kJmol)
BEF ligand BEFminusCu BEFminusNi BEFminusZnPower law 60932 62642 59691 54312Power law 121864 125284 119382 108625Phase boundary (contracting sphere) 16497 16816 16174 15009Phase boundary (contracting cylinder) 25894 26436 25383 23466Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 12135 13830 11756 07447
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 08090 09220 07837 04964
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 06067 06915 05878 03723
Valensi 2-dimensional diffusion 168354 171926 165034 152695Jander 3-dimensional diffusion 32995 33632 32349 30018Brounshtein-Ginstling 3-dimensional diffusion 56520 55015 55669 57981The values indicated in bold are closest to the 119864119886 value estimated by FC and SWmethods
14 Bioinorganic Chemistry and Applications
Table 7 Antibacterial activity of BEF ligand and its complexes
Compound Inhibition zone (mm)S sonnei E coli Klebsiella sp S aureus B subtilis S typhi
BEF ligand 15 13 13 14 15 12BEFndashCu 21 17 17 18 18 18BEFndashNi 18 15 18 17 20 15BEFndashZn 16 15 15 16 17 15Standard 26 28 26 25 27 28Control mdash mdash mdash mdash mdash mdashStandard amoxicillin control DMSO
Table 8 Antifungal activity of BEF ligand and its complexes
Compound Inhibition zone (mm)Aspergillus flavus Aspergillus niger Penicillium species Candida albicans Cryptococcus neoformans Mucorspecies
BEF ligand 14 12 12 13 11 12BEFndashCu 20 18 19 18 15 19BEFndashNi 17 14 17 15 13 13BEFndashZn 15 15 18 17 14 16Standard 20 21 19 21 18 22Control mdash mdash mdash mdash mdash mdashStandard fluconazole control DMSO
death There may be a rash resembling sunburn with peelingof skin The ligand and its complexes showed a humbleactivity against the growth of S aureus Bacillus subtilis arerod-shaped and nonpathogenic gram-positive bacteria TheBEF ligand and complexes showed superb activity againstthe growth of this bacterium Salmonella typhimurium is apathogenic gram-negative bacteria predominately found inthe intestinal lumen When the bacterial cells enter epithelialcells lining the intestine they cause host cell ruffling whichtemporarily damages the microvilli on the surface of the cellThis causes a rush of white blood cells into the mucosa andleads to diarrheaThe ligand and its metal complexes showeda moderate activity against the growth of the typhi species
A comparative account on the effect of antibacterialactivity against the chosen microbes indicates that the ligandand its three metal chelates show reasonable activity againstShigella sonnei (15 21 18 and 16mm) and Bacillus subtilis (1518 20 and 17mm) while the growth of other organisms ismoderately inhibited by the BEF ligand and its Cu2+ Ni2+and Zn2+ chelates The highest antibacterial action (21mm)has been observed for BEFndashCu2+ complex against Shigellasonnei
392 Antifungal Activity The antifungal activity of the BEFligand and its metal complexes has also given interestingresults and the growth inhibitions against the chosen fungalstrains are tabulated in Table 8 All the complexes and theirligand have an excellent activity against Aspergillus flavusa mold type fungal strain which may invade arteries of thelung or brain to cause infections and also produce a toxinAspergillus niger is one of the most common causes for
otomycosis The chelates and the ligand are found to havea reasonable activity for A niger Penicillium species causesinfection in humans and the resulting disease is known gener-ically as penicilliosis The ligand and the metal complexeshave wonderful activity against this species Further BEFndashCucomplex has a superior activity compared to the rest of othercomplexes Candida albicans is a diploid fungus and a causalagent of opportunistic oral and genital infections in humansand also emerged as an important cause of morbidity andmortality in immunocompromised patients The BEF ligandand its chelates possess a modest activity against C albicansover and above the standard Cryptococcus neoformans is anencapsulated yeast-like fungus that can live in both plantsand animals and cause lung infection The terpolymer ligandand its chelates have a fair activity against this fungal strainThe chelate compounds and the ligand havemoderate activityagainst Mucor species a filamentous fungus which causesseptic arthritis renal infections and pulmonary infections
From the antimicrobial results themetal complexes showhigher activity than their ligand which may be stronglydependent on the central metal ions and coordination num-bers metal chelates The higher activity due to the metal ionsshared with the donor atoms (N and S) of the thiazole ring ispresent in the ligand and the 120587-electron delocalization overthe chelate ring This effect increases the lipophilic characterof the metal ion which favors the permeation through thelipoid layers of the bacterial and fungal membranes [33 34]It is perceived that the factors such as solubility conductivitydipole moment and cell permeability may also contributeto the increased activity of the complexes [35 36] Fromthe results of the studies at 500 ppm concentration thecompounds establish better antimicrobial activity Hence it
Bioinorganic Chemistry and Applications 15
is an interesting result that a very low concentration of thecompound namely 500 ppm is enough to bring out aneffective inhibition against the chosen microbes
4 Conclusion
The synthesized 2-amino-6-nitro-benzothiazole-ethylene-diamine-formaldehyde terpolymer has acted as a ligandsuccessfully to form metal complexes The synthesized com-pounds were well characterized by various spectral andphysical analyses The morphological features suggest thatthe complexes are slightly more crystalline in nature thantheir parent ligandThe antibacterial and antifungal activitiesreveal that the terpolymer and its metal complexes can beactive against the selected bacterial and fungal strains Nearlyall of the compoundsmay suit well for drug delivery field afterchecking for their toxicology behaviour in thorough mannerThermal studies are also helpful to realize the standing capac-ity of the compounds which survive as antimicrobial coatingmaterials in various environmental conditions Because ofthe proven high stability nature and microbial preventioncapacity the BEF terpolymer and its Cu2+ Ni2+ and Zn2+complexes hold inadequate applications in biological fieldThe thermal stability of the terpolymer and its metal com-plexes was found greater From the thermodynamic andkinetic studies the abnormal low values of frequency factor(119885) indicate that the thermal decomposition reaction of BEFterpolymer and its metal complexes can be depicted as a slowreaction The BEF terpolymer and its metal complexes maybe following nearly a first order kinetics
Conflict of Interests
The authors certify that there is no conflict of interests withany financial organization regarding thematerial discussed inthe paper
Acknowledgments
The authors thank the Management and Principal ofOxford Engineering College Tiruchirappalli CoimbatoreInstitute of Technology Coimbatore Jamal Mohamed Col-lege (Autonomous) Tiruchirappalli Tamil Nadu and DrD Jeyakumar Scientist Central Electrochemical ResearchInstitute (CECRI-CSIR) Karaikudi Tamil Nadu for theirsupport and encouragement
References
[1] C U Pittman K S Ramachandran Jr and K R LowyerldquoSynthesis of fungicidal monomers polymers and latticesrdquoJournal of Coating Technology vol 54 pp 27ndash40 1982
[2] M N Patel J R Patel and D H Sutaria ldquoNovel co-ordinationpolychelatesrdquo Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry vol 24 no 8 pp 1297ndash1309 1994
[3] V V Ukey and H D Juneja ldquoSynthetic and spectroscopicstudies of chelate polymers involving azelaoyl bis-N-phenylhydroxamic acid with transition metal ionsrdquo Journal of AppliedPolymer Science vol 99 no 1 pp 273ndash278 2006
[4] S K-H Thiele and D R Wilson ldquoAlternate transition metalcomplex based diene polymerizationrdquo Polymer Reviews vol 43no 4 pp 581ndash628 2003
[5] N Nishat S Ahmad and T Ahamad ldquoSynthesis and character-ization of antibacterial polychelates of urea-formaldehyde resinwith Cr(III) Mn(II) Fe(III) Co(II) Ni(II) Cu(II) and Zn(II)metal ionsrdquo Journal of Applied Polymer Science vol 100 no 2pp 928ndash936 2006
[6] E Brzezinska G Koska and K Walczynski ldquoApplicationof thin-layer chromatographic data in quantitative structure-activity relationship assay of thiazole and benzothiazole deriva-tives with Hmdashantihistamine activityrdquo Journal of Chromatogra-phy A vol 1007 pp 145ndash155 2003
[7] M A R Ahamed and A R Burkanudeen ldquoMetal complexesof a novel terpolymer ligand synthesis spectral morphologythermal degradation kinetics and antimicrobial screeningrdquoJournal of Inorganic andOrganometallic Polymers andMaterialsvol 22 no 5 pp 1046ndash1061 2012
[8] B S Holla K V Malini V S Rao B K Sarojini and N SKumari ldquoSynthesis of some new 24-disubstituted thiazoles aspossible antibacterial and anti-inflammatory agentsrdquo EuropeanJournal of Medicinal Chemistry vol 38 no 3 pp 313ndash318 2003
[9] O I El-Sabbagh M M Baraka S M Ibrahim et al ldquoSynthesisand antiviral activity of new pyrazole and thiazole derivativesrdquoEuropean Journal of Medicinal Chemistry vol 44 no 9 pp3746ndash3753 2009
[10] A Andreani M Granaiola A Leoni A Locatelli R Morigiand M Rambaldi ldquoSynthesis and antitubercular activity ofimidazo[21-b]thiazolesrdquo European Journal of Medicinal Chem-istry vol 36 no 9 pp 743ndash746 2001
[11] E Yousif Y Farina K Kasar A Graisa and K Ayid ldquoCom-plexes of 2-thioacetic acid benzothiazole with somemetal ionsrdquoAmerican Journal of Applied Sciences vol 6 no 4 pp 582ndash5852009
[12] B P Mallikarjuna B S Sastry G V Suresh Kumar Y Rajen-draprasad S M Chandrashekar and K Sathisha ldquoSynthesis ofnew 4-isopropylthiazole hydrazide analogs and some derivedclubbed triazole oxadiazole ring systemsmdasha novel class ofpotential antibacterial antifungal and antitubercular agentsrdquoEuropean Journal of Medicinal Chemistry vol 44 pp 4739ndash4746 2009
[13] T Ahamad V Kumar and N Nishat ldquoNew class of anti-microbial agents synthesis characterization and anti-microbial activities of metal chelated polyureardquo Journal ofBiomedical Materials Research A vol 88 no 2 pp 288ndash2942009
[14] M V Patel J N Patel M B Dolia and R M Patel ldquoPolyether-ketones synthesis characterization and antimicrobial activityrdquoInternational Journal of Polymeric Materials and PolymericBiomaterials vol 54 no 11 pp 1059ndash1071 2005
[15] K R Alagawadi and S G Alegaon ldquoSynthesis characteriza-tion and antimicrobial activity evaluation of new 24-Thiazoli-dinediones bearing imidazo[21-b][134]thiadiazole moietyrdquoArabian Journal of Chemistry vol 4 no 4 pp 465ndash472 2011
[16] M Ashok B S Holla and N S Kumari ldquoConvenientone pot synthesis of some novel derivatives of thiazolo[23-b]dihydropyrimidinone possessing 4-methylthiophenyl moietyand evaluation of their antibacterial and antifungal activitiesrdquoEuropean Journal ofMedicinal Chemistry vol 42 no 3 pp 380ndash385 2007
16 Bioinorganic Chemistry and Applications
[17] T Ahamad V Kumar S Parveen and N Nishat ldquoIn vitroantibacterial and antifungal assay of poly-(ethylene oxamide-NN1015840-diacetate) and its polymer-metal complexesrdquo AppliedOrganometallic Chemistry vol 21 no 12 pp 1013ndash1021 2007
[18] R S Azarudeen M A R Ahamed and A R BurkanudeenldquoBiological and thermal investigations of polychelates derivedfrom a novel terpolymer ligandrdquo Journal of Polymer Researchvol 18 no 6 pp 1331ndash1341 2011
[19] R S Azarudeen and A R Burkanudeen ldquoSynthesis spectralmorphology thermal degradation kinetics and antibacterialstudies of terpolymermetal complexesrdquo Journal of Inorganic andOrganometallic Polymers and Materials vol 22 no 4 pp 791ndash806 2012
[20] R S Azarudeen and A R Burkanudeen ldquoStudies of newoligomer-metal complexes and their antibacterial activitiesrdquoPolymer International vol 62 no 3 pp 362ndash374 2013
[21] G S Devi A K Muthu D S Kumar S Rekha R Indhumathiand R Nandhini ldquoStudies on the antibacterial and antifungalactivities of the ethanolic extracts of Luffa cylindrica (Linn)fruitrdquo International Journal of Drug Development and Researchvol 1 pp 105ndash109 2013
[22] R M Silverstein and G C Bassler Spectrometric IdentificationofOrganic Compounds JohnWileyamp SonsNewYorkNYUSA2nd edition 1967
[23] Y-G Zhao H-Y Shen S-D Pan and M-Q Hu ldquoSyn-thesis characterization and properties of ethylenediamine-functionalized Fe
3O4magnetic polymers for removal of Cr(VI)
in wastewaterrdquo Journal of Hazardous Materials vol 182 no 1-3pp 295ndash302 2010
[24] Y R Sharma Elementary Organic Absorption Spectroscopy SChand amp Co Ltd New Delhi India 1980
[25] D Kivelson and R Neiman ldquoESR line shapes in glasses ofcopper complexesrdquoThe Journal of Chemical Physics vol 35 no1 pp 149ndash155 1961
[26] E Pretsch P Buhlmann and C Afflolter Structure Determi-nation of Organic Compounds Springer New York NY USA2000
[27] J L White Modern Magnetic Resonance Kluwer AcademicPress London UK 2006
[28] M M Patel M A Kapadia and J D Joshi ldquoThermal andcatalytic aspects of Ln(III) polymer-metal complexesrdquo PolymerInternational vol 58 no 7 pp 728ndash737 2009
[29] S Nanjundan C S J Selvamalar and R Jayakumar ldquoSynthesisand characterization of poly(3-acetyl-4-hydroxyphenyl acry-late) and its Cu(II) and Ni(II) complexesrdquo European PolymerJournal vol 40 no 10 pp 2313ndash2321 2004
[30] A V Nikolaev V A Logvinenco and L I Myachina ThermalAnalysis Academic Press New York NY USA 1969
[31] A Z El-Sonbati and M A Hefni ldquoPolymer complexes PartXXVImdashNovel mixed ligand poly-(5-vinyl salicylidene)-12-diaminobenzene complexesrdquo Polymer Degradation and Stabil-ity vol 43 no 1 pp 33ndash42 1994
[32] A S Aswar and N S Bhave ldquoThermal degradation studies ofsome new coordination polymersrdquo Polymer Degradation andStability vol 31 no 1 pp 115ndash124 1991
[33] T Ahamad V Kumar and N Nishat ldquoSynthesis characteri-zation and antimicrobial activity of transition metal chelatedthiourea-formaldehyde resinrdquo Polymer International vol 55no 12 pp 1398ndash1406 2006
[34] M M Patel M A Kapadia G P Patel and J D Joshi ldquoSynthe-sis characterization ion-exchange and antimicrobial study of
poly[(2-hydroxy-4-methoxybenzophenone) propylene] resinand its polychelates with lanthanides (III)rdquo Journal of AppliedPolymer Science vol 106 no 2 pp 1307ndash1317 2007
[35] M A Neelakantan S S Marriappan J Dharmaraja T Jeyaku-mar and K Muthukumaran ldquoSpectral XRD SEM and bio-logical activities of transition metal complexes of polydentateligands containing thiazole moietyrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 71 no 2 pp 628ndash635 2008
[36] G B Bagihalli S A Patil and P S Badami ldquoSynthesisphysicochemical investigation and biological studies of zinc(II)complexes with 124-triazole schiff basesrdquo Journal of the IranianChemical Society vol 6 no 2 pp 259ndash270 2009
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Inorganic ChemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Carbohydrate Chemistry
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
Physical Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom
Analytical Methods in Chemistry
Journal of
Volume 2014
Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
SpectroscopyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Medicinal ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chromatography Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Applied ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Theoretical ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Spectroscopy
Analytical ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Quantum Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Organic Chemistry International
ElectrochemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CatalystsJournal of
Bioinorganic Chemistry and Applications 7
(ppm)
12345678910
(a)
(ppm)1 0234567891011
(b)
Figure 4 1H-NMR spectra of (a) BEF ligand and (b) BEFndashZn
200 180 160 140 120 100 80 60 40 20 0(ppm)
(a)
200 180 160 140 120 100 80 60 40 20 0(ppm)
(b)
Figure 5 13C-NMR spectra of (a) BEF ligand and (b) BEFndashZn
O2N S
N
NH NH
M
NHCH2 CH2 CH2 CH2
n
O2NS
NNH NH NHCH2 CH2 CH2 CH2
n
H2OH2O
[M = Cu(II) Ni(II) and Zn(II)]
Figure 6 Proposed geometry of BEF metal complexes
Figure 5 The observed chemical shifts are assigned on thebasis of the literature [22 27]The spectrum of ligand showedthat the corresponding peaks at 1717 1585 1315 1219 14061167 and 1253 ppm are attributed to the aromatic carbonsof the benzothiazole ring The peak appearing at 502 ppmis assigned to the methylenic carbon of NHndashCH
2bridge in
the ligand The spectrum of Zn2+ complex showed the peaksfor aromatic ring in the same region which was appearingin its parent ligand The shifting of the methylene carbonfrom 502 to 561 ppm from its ligand clearly suggests that the
coordination takes place between the nitrogen atoms of theethylenediamine moiety
From the elemental and spectral data (FTIR UV-VisESR and NMR (1H and 13C)) the structure of the BEF ter-polymer ligand and its metal complexes has been confirmedThe proposed geometry of the BEF complexes is shown inFigure 6
36 Surface Analysis The SEM is applied to understandthe surface features of the polymeric materials The SEM
8 Bioinorganic Chemistry and Applications
(a) (b)
(c) (d)
(e)
Figure 7 SEM images of (a) and (b) BEF ligand (c) BEFndashCu (d) BEFndashNi and (e) BEFndashZn
photographs in times1000 and times2000 magnifications for BEFligand and times3000 magnifications for BEF complexes areshown in Figure 7 The white bar at the bottom of the SEMphotographs represents the scale The SEM photographs ofthe BEF terpolymer ligand show leaf like appearance Thescattered structure of the terpolymer establishes a transitionstate between the crystalline and the amorphous phases [28]
Themorphology of BEF terpolymer resin exhibits growthof crystals from polymer solutions corresponding to the
most prominent organization in polymers on a large scalewith spherulites Ideally spherulites are the aggregates ofsubmicroscopic size particles Spherulites are characterizedby secondary structural features such as faint corrugationsThe SEM photographs of polymers have an appreciableamorphous fraction with a small amount of shallow pitsThe surface of BEF metal complexes contributes to greatersegments of crystalline regions compared to their parentligand which may arise from the contraction of the voids by
Bioinorganic Chemistry and Applications 9
Inte
nsity
(au
)
0 20 40 60 802120579
(a)
Inte
nsity
(au
)
0 20 40 60 802120579
(b)
Inte
nsity
(au
)
0 20 40 60 802120579
(c)
Inte
nsity
(au
)
0 20 40 60 802120579
(d)
Figure 8 XRD patterns of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
the cooperative contribution of the ligand for complexationwith metal ions or the disappearance of the voids in therearrangement of polymer chains for complexation withmetal ions This is a further evidence for the complexationof BEF terpolymer with metal ions
37 XRD Studies X-ray diffraction (XRD) patterns of BEFand its metal complexes are shown in Figure 8 It provides adetailed comparative account of the behavior of the terpoly-mer and itsmetal complexesThepattern of BEF ligand showsthe main characteristic peak and broad shoulder In view ofthe relative half value width it may be concluded that thepolymer is partially crystalline and the broad characteristicpeak indicates the amorphous nature of the terpolymerTherefore the BEF terpolymer has transition state betweenamorphous state and crystalline state whereas its metalchelates possess crystalline nature The enhanced crystallinebehavior of the BEF complexes may be due to the insertion ofmetal ions with their parent ligand [29]
38 Thermal Stability Thermal stability of the BEF terpoly-mer and its metal complexes was analyzed by thermogravi-metric analysis (TGA) The thermograms of the terpolymer
and its metal complexes are shown in Figure 9 and their per-centages of weight loss at various temperatures are presentedin Table 4
381Thermal Stability of BEF Terpolymer From the thermo-gram of BEF terpolymer there were three stages of degra-dation (200ndash320∘C 320ndash580∘C and 580ndash835∘C) observedThe first stage of degradation was observed between 200∘Cand 320∘C (found 5883 calc 5794) which reveals thedegradation of the benzothiazole ring The second stageof degradation begins at 320∘C and ends at 580∘C (found1003 calc 0931) which may be due to the eliminationof cross-linkages The third and final stage of degradation isobserved above 580∘C and continued up to 825∘C (found2506 calc 2473) which can be attributed to the weightloss of aliphatic group (ethylenediamine moiety) from theBEF terpolymer
382 Thermal Stability of BEF Metal Complexes In generalthe water of hydration may be considered as either crystalwater molecules or coordination water molecules Accordingto Nikolaev et al [30] water eliminated below 150∘C can beconsidered as crystal or lattice water and water eliminated
10 Bioinorganic Chemistry and Applications
Table 4 TGA data for thermal stability
Compound Percentage of weight loss at various temperatures11987950
lowast (∘C) 119879maxlowastlowast (∘C)
100 200 300 400 500 600 700 800 (∘C)BEF ligand 0153 0365 4414 6236 6718 7140 8224 9442 310 825BEFminusCu 0194 1432 3180 4301 4996 5549 6686 8122 500 860BEFminusNi 0893 1660 3735 4935 6460 8767 mdash mdash 405 650BEFminusZn 1464 2262 3833 4616 5726 6492 7614 9129 425 830lowastTemperature of 50 weight loss lowastlowastmaximum decomposition temperature
80
60
40
20
0
0
(a)(b)
(c)(d)
200 400 600 800 1000
100
Wei
ght (
)
Temperature (∘C)
Figure 9 TGA of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d)BEFndashZn
above 150∘C may be due to its coordination to the metalatom present in chelates In the present study in the case ofBEFndashCu2+ Ni2+ and Zn2+ complexes the removal of waterfrom the complex was completed within 150∘C These watermolecules are probably crystal or lattice water moleculesTheremoval of water molecules observed in the range of 150ndash200∘C (found 559ndash608 calc 545ndash551) of all the metalchelates is due to the elimination of two coordinated watermolecules These observations further confirm the distortedoctahedral geometry of BEF metal complexes
The thermogravimetric curves of all the BEF metalchelates showed two degradation steps after loss of watermolecules whichmay indicate that the first step (200ndash600∘C)is faster than the second step (600ndash860∘C) This may bedue to the fact that the noncoordinated part of the liganddecomposes firstwhile the coordinated part decomposes laterand finally it may form the representative metal oxides Theweight of the residues confirms fairly well that ofmetal oxides(found 1247ndash1362 calc 1143ndash1232)
The thermal degradation data of the BEF terpolymerand its metal complexes reveal that the polymeric complexesshow better stability than the BEF terpolymer due to thecoordination of metal ions The order of thermal stability ofthe BEF polymer and its complexes is BEFndashCu2+ gt BEFndashZn2+ gt BEF ligand gt BEFndashNi2+ The greater stability of themetal complexes may be due to the coordination and theenhanced cross linking nature with crowd effect of the metal
complexes [31] In the case of Ni2+ complex the degradationoccurred exceptionally at low temperature compared to theirligand which may be due to the oxidation of polymer by thecatalytic action of the metal ion [32]
383 Thermal Kinetics
(1) Sharp-Wentworth and Freeman-Carroll Method Ther-mal kinetic analysis was performed using Sharp-Wentworthmethod and Freeman-Carroll methods The activationenergy (119864
119886) and order of reaction (119899) plots for BEF terpoly-
mer ligand and its metal complexes by Sharp-Wentworthand Freeman-Carroll methods are shown in Figures 10 11and 12 The expressions used to calculate the kinetic andthermodynamic parameters are presented as follows
(i) Entropy change (Δ119878)
Intercept = log 119870119877
ℎΦ119864119886
+Δ119878
2303119877 (2)
where 119870 = 13806 times 10minus16 ergdegmole 119877 =
1987 caldegmole (8314 JKMol) ℎ = 6625 times
10minus27 erg sec Φ = 0166 Δ119878 = change in entropyand 119864
119886= activation energy from graph
(ii) Free energy change (Δ119865)
Δ119865 = Δ119867 minus 119879Δ119878 (3)
where Δ119867 = enthalpy change = activation energy 119879 =temperature in119870 and Δ119878 = result from (2)
(iii) Frequency factor (119885)
11986123
=log119885119864
119886
119877Φ (4)
11986123
= log 3 + log [1 minus 3radic1 minus 120572] minus log119901 (119909) (5)
where 119885 is the frequency factor 119861 is calculatedfrom (5) log119901(119909) is calculated from Doylersquos tablecorresponding to activation energy and 120572 is degreeof transformation (120572 = 119908119882
119888)
(iv) Apparent entropy (119878lowast)
119878lowast= 2303 log 119885ℎ
119877119879lowast (6)
where119885 is calculated from (4) and 119879lowast is half decom-position temperature
Bioinorganic Chemistry and Applications 11
1000T (Kminus1)
Intercept = minus535
minus45
minus50
minus55
minus60
minus65
minus70
minus75
minus80
10 15 20 25 30
Ea = 952
log[
(dC
dT
)(1
minusC
)]
(a)
minus64
minus62
minus60
minus58
minus56
minus54
minus52
1000T (Kminus1)10 15 20 25 30
Intercept = minus527
Ea = 1297
log[
(dC
dT
)(1
minusC
)]
(b)
minus64
minus62
minus50
minus52
minus54
minus56
minus58
minus60
1000T (Kminus1)10 15 20 25 30
Intercept = minus513
Ea = 693
log[
(dC
dT
)(1
minusC
)]
(c)
minus50
minus51
minus52
minus53
minus54
minus55
minus56
minus57
minus58
minus59
1000T (Kminus1)10 15 20 25 30
Intercept = minus538
Ea = 1108
log[
(dC
dT
)(1
minusC
)]
(d)
Figure 10 Sharp-Wentworth plots of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Table 5 Kinetic and thermodynamic parameters data
CompoundActivation energy
(119864119886kJmolminus1) Entropy change
(Δ119878J)Free energy
change (Δ119865kJ)Frequency
factor (119885sminus1)Apparent
entropy (119878lowastJ)Order of
reaction (119899)lowastSW lowastlowastFC
BEF ligand 952 1039 minus15811 5940 1310 minus2295 090BEFminusCu 1297 1367 minus15425 9079 1205 minus2331 104BEFminusNi 693 460 minus16290 7057 1537 minus2294 093BEFminusZn 1108 1213 minus16001 8013 1243 minus2318 102lowastSW Sharp-Wentworth lowastlowastFC Freeman-Carroll
Further from the knowledge of activation energy cal-culated by Freeman-Carroll method it is possible to eval-uate the values of various thermodynamic parameters Theorder of reaction (119899) and activation energy (119864
119886) and the
thermodynamic parameters such as frequency factor (119885)entropy change (Δ119878) free energy change (Δ119865) and apparententropy (119878lowast) are presented inTable 5The119864
119886values calculated
by SW and FC methods are in good agreement with eachother The order of activation energies for BEF ligand andits Cu2+ Ni2+ and Zn2+ complexes is parallel to the orderof their thermal stability [32] The values of thermodynamic
parameters were comparable indicating a common modeof decomposition reaction The abnormal low values offrequency factor (119885) indicate that the decomposition reactionof BEF terpolymer and its metal complexes can be depictedas a slow reaction The order of reactions (119899) of BEF ligandand its metal complexes is found to be 090 104 093 and102 respectively Hence the BEF terpolymer and its mealcomplexes may be following nearly a first order kinetics
(2) Phadnis-Deshpande Method The activation energiescalculated for BEF ligand and its metal complexes using
12 Bioinorganic Chemistry and Applications
minus00012minus00010minus00008minus00006minus00004minus00002minus00000
26242220181614121008060402
log(dWdt)
(1T)
n = 090
logW
r
logWr
(a)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
20
19
18
17
16
15
14
13
12
11
10
log(dWdt)
(1T)
n = 104
logWr
logW
r
(b)
15
16
17
18
19
14
13
12
11
10
09
log(dWdt)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
(1T)
n = 093logW
r
logWr
(c)
15
16
17
18
14
13
12
11
10
log(dWdt)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
(1T)
n = 102
logW
r
logWr
(d)
Figure 11 Freeman-Carroll plots (119899) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Phadnis-Deshpande method are presented in Table 6 Fromthe 119864
119886values it is possible to propose the degradation
reactionmechanism using PDmethod Further the 119864119886values
calculated by PD method are in good agreement with FCand SW methods Based on the closest 119864
119886values calculated
by PD SW and FC methods the Power law mechanismsuits very well for the BEF ligand and BEFndashCu and BEFndashZn metal complexes However BEFndashNi complex follows theBrounshtein-Ginstling 3-dimensional diffusion mechanism
39 Biological Studies
391 Antibacterial Activity To determine the antibacterialactivity of the BEF terpolymer and its Cu2+ Ni2+ andZn2+ complexes the disc diffusion method was used withamoxicillin as the standard antibiotic The prepared com-pounds were tested against Shigella sonnei Escherichia coliKlebsiella species Staphylococcus aureus Bacillus subtilis andSalmonella typhimuriummicroorganisms
Table 7 contains the screening results corresponding tothe polymeric ligand and its metal complexes with fairinhibition of growth against the tested organisms Shigella
sonnei is a nonmotile non-spore-forming and facultativeanaerobic gram-negative bacterium Shigella bacteria multi-ply within colonic epithelial cells and cause mucosal ulcer-ation inflammation bleeding high fever malaise diarrheaand tenesmus The ligand and its metal complexes showeda reasonable activity against the S sonnei species E coliis an aerobic gram-negative and rod shaped bacteriumInfection of E coli can lead to bloody diarrhea and kidneyfailureThe polymeric ligand and its complexes hold amodestactivity against the E coli Klebsiella is a genus of nonmotileand gram-negative bacteria that infects sites such as nasalpassages liver lung urinary tract bloodstream eye boneand joints It causes a wide range of disease states notablypneumonia septicemia soft tissue infections biliary tractinfection infection of the upper and lower respiratory tractand liver abscess The BEF ligand and its metal complexesshowed a reasonable result against the growth of KlebsiellaStaphylococcus aureus a gram-positive and spherical bac-terium leads to life-threatening diseases like pneumoniaosteomyelitis endocarditis and toxic shock syndrome Toxicshock syndrome is characterized by the sudden onset of highfever vomiting diarrhea and muscle aches followed by lowblood pressure (hypotension) which can lead to shock and
Bioinorganic Chemistry and Applications 13
log[g
(120572)T3]
minus95
minus90
minus85
minus80
minus75
10 15 20 25 30
Intercept = minus825
Ea = 1039
1000T (Kminus1)
(a)
log[g
(120572)T3]
minus78
minus80
minus82
minus84
minus86
minus88
minus90
minus92
minus94
minus96
minus76
Intercept = minus805
Ea = 1367
10 15 20 25 30
1000T (Kminus1)
(b)
log[g
(120572)T3]
minus77
minus78
minus79
minus80
minus81
minus82
minus83
minus84
minus85
minus86
minus87
minus88minus89
Intercept = minus849
Ea = 460
10 15 20 25 30
1000T (Kminus1)
(c)
minus78
minus80
minus82
minus84
minus86
minus7610 15 20 25 30
1000T (Kminus1)
log[g
(120572)T3]
Intercept = minus835
Ea = 1213
(d)
Figure 12 Freeman-Carroll plots (119864119886) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Table 6 Activation energies calculated by Phadnis-Deshpande method
Reaction mechanism model Energy of activation (119864119886) (kJmol)
BEF ligand BEFminusCu BEFminusNi BEFminusZnPower law 60932 62642 59691 54312Power law 121864 125284 119382 108625Phase boundary (contracting sphere) 16497 16816 16174 15009Phase boundary (contracting cylinder) 25894 26436 25383 23466Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 12135 13830 11756 07447
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 08090 09220 07837 04964
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 06067 06915 05878 03723
Valensi 2-dimensional diffusion 168354 171926 165034 152695Jander 3-dimensional diffusion 32995 33632 32349 30018Brounshtein-Ginstling 3-dimensional diffusion 56520 55015 55669 57981The values indicated in bold are closest to the 119864119886 value estimated by FC and SWmethods
14 Bioinorganic Chemistry and Applications
Table 7 Antibacterial activity of BEF ligand and its complexes
Compound Inhibition zone (mm)S sonnei E coli Klebsiella sp S aureus B subtilis S typhi
BEF ligand 15 13 13 14 15 12BEFndashCu 21 17 17 18 18 18BEFndashNi 18 15 18 17 20 15BEFndashZn 16 15 15 16 17 15Standard 26 28 26 25 27 28Control mdash mdash mdash mdash mdash mdashStandard amoxicillin control DMSO
Table 8 Antifungal activity of BEF ligand and its complexes
Compound Inhibition zone (mm)Aspergillus flavus Aspergillus niger Penicillium species Candida albicans Cryptococcus neoformans Mucorspecies
BEF ligand 14 12 12 13 11 12BEFndashCu 20 18 19 18 15 19BEFndashNi 17 14 17 15 13 13BEFndashZn 15 15 18 17 14 16Standard 20 21 19 21 18 22Control mdash mdash mdash mdash mdash mdashStandard fluconazole control DMSO
death There may be a rash resembling sunburn with peelingof skin The ligand and its complexes showed a humbleactivity against the growth of S aureus Bacillus subtilis arerod-shaped and nonpathogenic gram-positive bacteria TheBEF ligand and complexes showed superb activity againstthe growth of this bacterium Salmonella typhimurium is apathogenic gram-negative bacteria predominately found inthe intestinal lumen When the bacterial cells enter epithelialcells lining the intestine they cause host cell ruffling whichtemporarily damages the microvilli on the surface of the cellThis causes a rush of white blood cells into the mucosa andleads to diarrheaThe ligand and its metal complexes showeda moderate activity against the growth of the typhi species
A comparative account on the effect of antibacterialactivity against the chosen microbes indicates that the ligandand its three metal chelates show reasonable activity againstShigella sonnei (15 21 18 and 16mm) and Bacillus subtilis (1518 20 and 17mm) while the growth of other organisms ismoderately inhibited by the BEF ligand and its Cu2+ Ni2+and Zn2+ chelates The highest antibacterial action (21mm)has been observed for BEFndashCu2+ complex against Shigellasonnei
392 Antifungal Activity The antifungal activity of the BEFligand and its metal complexes has also given interestingresults and the growth inhibitions against the chosen fungalstrains are tabulated in Table 8 All the complexes and theirligand have an excellent activity against Aspergillus flavusa mold type fungal strain which may invade arteries of thelung or brain to cause infections and also produce a toxinAspergillus niger is one of the most common causes for
otomycosis The chelates and the ligand are found to havea reasonable activity for A niger Penicillium species causesinfection in humans and the resulting disease is known gener-ically as penicilliosis The ligand and the metal complexeshave wonderful activity against this species Further BEFndashCucomplex has a superior activity compared to the rest of othercomplexes Candida albicans is a diploid fungus and a causalagent of opportunistic oral and genital infections in humansand also emerged as an important cause of morbidity andmortality in immunocompromised patients The BEF ligandand its chelates possess a modest activity against C albicansover and above the standard Cryptococcus neoformans is anencapsulated yeast-like fungus that can live in both plantsand animals and cause lung infection The terpolymer ligandand its chelates have a fair activity against this fungal strainThe chelate compounds and the ligand havemoderate activityagainst Mucor species a filamentous fungus which causesseptic arthritis renal infections and pulmonary infections
From the antimicrobial results themetal complexes showhigher activity than their ligand which may be stronglydependent on the central metal ions and coordination num-bers metal chelates The higher activity due to the metal ionsshared with the donor atoms (N and S) of the thiazole ring ispresent in the ligand and the 120587-electron delocalization overthe chelate ring This effect increases the lipophilic characterof the metal ion which favors the permeation through thelipoid layers of the bacterial and fungal membranes [33 34]It is perceived that the factors such as solubility conductivitydipole moment and cell permeability may also contributeto the increased activity of the complexes [35 36] Fromthe results of the studies at 500 ppm concentration thecompounds establish better antimicrobial activity Hence it
Bioinorganic Chemistry and Applications 15
is an interesting result that a very low concentration of thecompound namely 500 ppm is enough to bring out aneffective inhibition against the chosen microbes
4 Conclusion
The synthesized 2-amino-6-nitro-benzothiazole-ethylene-diamine-formaldehyde terpolymer has acted as a ligandsuccessfully to form metal complexes The synthesized com-pounds were well characterized by various spectral andphysical analyses The morphological features suggest thatthe complexes are slightly more crystalline in nature thantheir parent ligandThe antibacterial and antifungal activitiesreveal that the terpolymer and its metal complexes can beactive against the selected bacterial and fungal strains Nearlyall of the compoundsmay suit well for drug delivery field afterchecking for their toxicology behaviour in thorough mannerThermal studies are also helpful to realize the standing capac-ity of the compounds which survive as antimicrobial coatingmaterials in various environmental conditions Because ofthe proven high stability nature and microbial preventioncapacity the BEF terpolymer and its Cu2+ Ni2+ and Zn2+complexes hold inadequate applications in biological fieldThe thermal stability of the terpolymer and its metal com-plexes was found greater From the thermodynamic andkinetic studies the abnormal low values of frequency factor(119885) indicate that the thermal decomposition reaction of BEFterpolymer and its metal complexes can be depicted as a slowreaction The BEF terpolymer and its metal complexes maybe following nearly a first order kinetics
Conflict of Interests
The authors certify that there is no conflict of interests withany financial organization regarding thematerial discussed inthe paper
Acknowledgments
The authors thank the Management and Principal ofOxford Engineering College Tiruchirappalli CoimbatoreInstitute of Technology Coimbatore Jamal Mohamed Col-lege (Autonomous) Tiruchirappalli Tamil Nadu and DrD Jeyakumar Scientist Central Electrochemical ResearchInstitute (CECRI-CSIR) Karaikudi Tamil Nadu for theirsupport and encouragement
References
[1] C U Pittman K S Ramachandran Jr and K R LowyerldquoSynthesis of fungicidal monomers polymers and latticesrdquoJournal of Coating Technology vol 54 pp 27ndash40 1982
[2] M N Patel J R Patel and D H Sutaria ldquoNovel co-ordinationpolychelatesrdquo Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry vol 24 no 8 pp 1297ndash1309 1994
[3] V V Ukey and H D Juneja ldquoSynthetic and spectroscopicstudies of chelate polymers involving azelaoyl bis-N-phenylhydroxamic acid with transition metal ionsrdquo Journal of AppliedPolymer Science vol 99 no 1 pp 273ndash278 2006
[4] S K-H Thiele and D R Wilson ldquoAlternate transition metalcomplex based diene polymerizationrdquo Polymer Reviews vol 43no 4 pp 581ndash628 2003
[5] N Nishat S Ahmad and T Ahamad ldquoSynthesis and character-ization of antibacterial polychelates of urea-formaldehyde resinwith Cr(III) Mn(II) Fe(III) Co(II) Ni(II) Cu(II) and Zn(II)metal ionsrdquo Journal of Applied Polymer Science vol 100 no 2pp 928ndash936 2006
[6] E Brzezinska G Koska and K Walczynski ldquoApplicationof thin-layer chromatographic data in quantitative structure-activity relationship assay of thiazole and benzothiazole deriva-tives with Hmdashantihistamine activityrdquo Journal of Chromatogra-phy A vol 1007 pp 145ndash155 2003
[7] M A R Ahamed and A R Burkanudeen ldquoMetal complexesof a novel terpolymer ligand synthesis spectral morphologythermal degradation kinetics and antimicrobial screeningrdquoJournal of Inorganic andOrganometallic Polymers andMaterialsvol 22 no 5 pp 1046ndash1061 2012
[8] B S Holla K V Malini V S Rao B K Sarojini and N SKumari ldquoSynthesis of some new 24-disubstituted thiazoles aspossible antibacterial and anti-inflammatory agentsrdquo EuropeanJournal of Medicinal Chemistry vol 38 no 3 pp 313ndash318 2003
[9] O I El-Sabbagh M M Baraka S M Ibrahim et al ldquoSynthesisand antiviral activity of new pyrazole and thiazole derivativesrdquoEuropean Journal of Medicinal Chemistry vol 44 no 9 pp3746ndash3753 2009
[10] A Andreani M Granaiola A Leoni A Locatelli R Morigiand M Rambaldi ldquoSynthesis and antitubercular activity ofimidazo[21-b]thiazolesrdquo European Journal of Medicinal Chem-istry vol 36 no 9 pp 743ndash746 2001
[11] E Yousif Y Farina K Kasar A Graisa and K Ayid ldquoCom-plexes of 2-thioacetic acid benzothiazole with somemetal ionsrdquoAmerican Journal of Applied Sciences vol 6 no 4 pp 582ndash5852009
[12] B P Mallikarjuna B S Sastry G V Suresh Kumar Y Rajen-draprasad S M Chandrashekar and K Sathisha ldquoSynthesis ofnew 4-isopropylthiazole hydrazide analogs and some derivedclubbed triazole oxadiazole ring systemsmdasha novel class ofpotential antibacterial antifungal and antitubercular agentsrdquoEuropean Journal of Medicinal Chemistry vol 44 pp 4739ndash4746 2009
[13] T Ahamad V Kumar and N Nishat ldquoNew class of anti-microbial agents synthesis characterization and anti-microbial activities of metal chelated polyureardquo Journal ofBiomedical Materials Research A vol 88 no 2 pp 288ndash2942009
[14] M V Patel J N Patel M B Dolia and R M Patel ldquoPolyether-ketones synthesis characterization and antimicrobial activityrdquoInternational Journal of Polymeric Materials and PolymericBiomaterials vol 54 no 11 pp 1059ndash1071 2005
[15] K R Alagawadi and S G Alegaon ldquoSynthesis characteriza-tion and antimicrobial activity evaluation of new 24-Thiazoli-dinediones bearing imidazo[21-b][134]thiadiazole moietyrdquoArabian Journal of Chemistry vol 4 no 4 pp 465ndash472 2011
[16] M Ashok B S Holla and N S Kumari ldquoConvenientone pot synthesis of some novel derivatives of thiazolo[23-b]dihydropyrimidinone possessing 4-methylthiophenyl moietyand evaluation of their antibacterial and antifungal activitiesrdquoEuropean Journal ofMedicinal Chemistry vol 42 no 3 pp 380ndash385 2007
16 Bioinorganic Chemistry and Applications
[17] T Ahamad V Kumar S Parveen and N Nishat ldquoIn vitroantibacterial and antifungal assay of poly-(ethylene oxamide-NN1015840-diacetate) and its polymer-metal complexesrdquo AppliedOrganometallic Chemistry vol 21 no 12 pp 1013ndash1021 2007
[18] R S Azarudeen M A R Ahamed and A R BurkanudeenldquoBiological and thermal investigations of polychelates derivedfrom a novel terpolymer ligandrdquo Journal of Polymer Researchvol 18 no 6 pp 1331ndash1341 2011
[19] R S Azarudeen and A R Burkanudeen ldquoSynthesis spectralmorphology thermal degradation kinetics and antibacterialstudies of terpolymermetal complexesrdquo Journal of Inorganic andOrganometallic Polymers and Materials vol 22 no 4 pp 791ndash806 2012
[20] R S Azarudeen and A R Burkanudeen ldquoStudies of newoligomer-metal complexes and their antibacterial activitiesrdquoPolymer International vol 62 no 3 pp 362ndash374 2013
[21] G S Devi A K Muthu D S Kumar S Rekha R Indhumathiand R Nandhini ldquoStudies on the antibacterial and antifungalactivities of the ethanolic extracts of Luffa cylindrica (Linn)fruitrdquo International Journal of Drug Development and Researchvol 1 pp 105ndash109 2013
[22] R M Silverstein and G C Bassler Spectrometric IdentificationofOrganic Compounds JohnWileyamp SonsNewYorkNYUSA2nd edition 1967
[23] Y-G Zhao H-Y Shen S-D Pan and M-Q Hu ldquoSyn-thesis characterization and properties of ethylenediamine-functionalized Fe
3O4magnetic polymers for removal of Cr(VI)
in wastewaterrdquo Journal of Hazardous Materials vol 182 no 1-3pp 295ndash302 2010
[24] Y R Sharma Elementary Organic Absorption Spectroscopy SChand amp Co Ltd New Delhi India 1980
[25] D Kivelson and R Neiman ldquoESR line shapes in glasses ofcopper complexesrdquoThe Journal of Chemical Physics vol 35 no1 pp 149ndash155 1961
[26] E Pretsch P Buhlmann and C Afflolter Structure Determi-nation of Organic Compounds Springer New York NY USA2000
[27] J L White Modern Magnetic Resonance Kluwer AcademicPress London UK 2006
[28] M M Patel M A Kapadia and J D Joshi ldquoThermal andcatalytic aspects of Ln(III) polymer-metal complexesrdquo PolymerInternational vol 58 no 7 pp 728ndash737 2009
[29] S Nanjundan C S J Selvamalar and R Jayakumar ldquoSynthesisand characterization of poly(3-acetyl-4-hydroxyphenyl acry-late) and its Cu(II) and Ni(II) complexesrdquo European PolymerJournal vol 40 no 10 pp 2313ndash2321 2004
[30] A V Nikolaev V A Logvinenco and L I Myachina ThermalAnalysis Academic Press New York NY USA 1969
[31] A Z El-Sonbati and M A Hefni ldquoPolymer complexes PartXXVImdashNovel mixed ligand poly-(5-vinyl salicylidene)-12-diaminobenzene complexesrdquo Polymer Degradation and Stabil-ity vol 43 no 1 pp 33ndash42 1994
[32] A S Aswar and N S Bhave ldquoThermal degradation studies ofsome new coordination polymersrdquo Polymer Degradation andStability vol 31 no 1 pp 115ndash124 1991
[33] T Ahamad V Kumar and N Nishat ldquoSynthesis characteri-zation and antimicrobial activity of transition metal chelatedthiourea-formaldehyde resinrdquo Polymer International vol 55no 12 pp 1398ndash1406 2006
[34] M M Patel M A Kapadia G P Patel and J D Joshi ldquoSynthe-sis characterization ion-exchange and antimicrobial study of
poly[(2-hydroxy-4-methoxybenzophenone) propylene] resinand its polychelates with lanthanides (III)rdquo Journal of AppliedPolymer Science vol 106 no 2 pp 1307ndash1317 2007
[35] M A Neelakantan S S Marriappan J Dharmaraja T Jeyaku-mar and K Muthukumaran ldquoSpectral XRD SEM and bio-logical activities of transition metal complexes of polydentateligands containing thiazole moietyrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 71 no 2 pp 628ndash635 2008
[36] G B Bagihalli S A Patil and P S Badami ldquoSynthesisphysicochemical investigation and biological studies of zinc(II)complexes with 124-triazole schiff basesrdquo Journal of the IranianChemical Society vol 6 no 2 pp 259ndash270 2009
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Inorganic ChemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Carbohydrate Chemistry
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
Physical Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom
Analytical Methods in Chemistry
Journal of
Volume 2014
Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
SpectroscopyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Medicinal ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chromatography Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Applied ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Theoretical ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Spectroscopy
Analytical ChemistryInternational Journal of
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Quantum Chemistry
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Organic Chemistry International
ElectrochemistryInternational Journal of
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CatalystsJournal of
8 Bioinorganic Chemistry and Applications
(a) (b)
(c) (d)
(e)
Figure 7 SEM images of (a) and (b) BEF ligand (c) BEFndashCu (d) BEFndashNi and (e) BEFndashZn
photographs in times1000 and times2000 magnifications for BEFligand and times3000 magnifications for BEF complexes areshown in Figure 7 The white bar at the bottom of the SEMphotographs represents the scale The SEM photographs ofthe BEF terpolymer ligand show leaf like appearance Thescattered structure of the terpolymer establishes a transitionstate between the crystalline and the amorphous phases [28]
Themorphology of BEF terpolymer resin exhibits growthof crystals from polymer solutions corresponding to the
most prominent organization in polymers on a large scalewith spherulites Ideally spherulites are the aggregates ofsubmicroscopic size particles Spherulites are characterizedby secondary structural features such as faint corrugationsThe SEM photographs of polymers have an appreciableamorphous fraction with a small amount of shallow pitsThe surface of BEF metal complexes contributes to greatersegments of crystalline regions compared to their parentligand which may arise from the contraction of the voids by
Bioinorganic Chemistry and Applications 9
Inte
nsity
(au
)
0 20 40 60 802120579
(a)
Inte
nsity
(au
)
0 20 40 60 802120579
(b)
Inte
nsity
(au
)
0 20 40 60 802120579
(c)
Inte
nsity
(au
)
0 20 40 60 802120579
(d)
Figure 8 XRD patterns of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
the cooperative contribution of the ligand for complexationwith metal ions or the disappearance of the voids in therearrangement of polymer chains for complexation withmetal ions This is a further evidence for the complexationof BEF terpolymer with metal ions
37 XRD Studies X-ray diffraction (XRD) patterns of BEFand its metal complexes are shown in Figure 8 It provides adetailed comparative account of the behavior of the terpoly-mer and itsmetal complexesThepattern of BEF ligand showsthe main characteristic peak and broad shoulder In view ofthe relative half value width it may be concluded that thepolymer is partially crystalline and the broad characteristicpeak indicates the amorphous nature of the terpolymerTherefore the BEF terpolymer has transition state betweenamorphous state and crystalline state whereas its metalchelates possess crystalline nature The enhanced crystallinebehavior of the BEF complexes may be due to the insertion ofmetal ions with their parent ligand [29]
38 Thermal Stability Thermal stability of the BEF terpoly-mer and its metal complexes was analyzed by thermogravi-metric analysis (TGA) The thermograms of the terpolymer
and its metal complexes are shown in Figure 9 and their per-centages of weight loss at various temperatures are presentedin Table 4
381Thermal Stability of BEF Terpolymer From the thermo-gram of BEF terpolymer there were three stages of degra-dation (200ndash320∘C 320ndash580∘C and 580ndash835∘C) observedThe first stage of degradation was observed between 200∘Cand 320∘C (found 5883 calc 5794) which reveals thedegradation of the benzothiazole ring The second stageof degradation begins at 320∘C and ends at 580∘C (found1003 calc 0931) which may be due to the eliminationof cross-linkages The third and final stage of degradation isobserved above 580∘C and continued up to 825∘C (found2506 calc 2473) which can be attributed to the weightloss of aliphatic group (ethylenediamine moiety) from theBEF terpolymer
382 Thermal Stability of BEF Metal Complexes In generalthe water of hydration may be considered as either crystalwater molecules or coordination water molecules Accordingto Nikolaev et al [30] water eliminated below 150∘C can beconsidered as crystal or lattice water and water eliminated
10 Bioinorganic Chemistry and Applications
Table 4 TGA data for thermal stability
Compound Percentage of weight loss at various temperatures11987950
lowast (∘C) 119879maxlowastlowast (∘C)
100 200 300 400 500 600 700 800 (∘C)BEF ligand 0153 0365 4414 6236 6718 7140 8224 9442 310 825BEFminusCu 0194 1432 3180 4301 4996 5549 6686 8122 500 860BEFminusNi 0893 1660 3735 4935 6460 8767 mdash mdash 405 650BEFminusZn 1464 2262 3833 4616 5726 6492 7614 9129 425 830lowastTemperature of 50 weight loss lowastlowastmaximum decomposition temperature
80
60
40
20
0
0
(a)(b)
(c)(d)
200 400 600 800 1000
100
Wei
ght (
)
Temperature (∘C)
Figure 9 TGA of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d)BEFndashZn
above 150∘C may be due to its coordination to the metalatom present in chelates In the present study in the case ofBEFndashCu2+ Ni2+ and Zn2+ complexes the removal of waterfrom the complex was completed within 150∘C These watermolecules are probably crystal or lattice water moleculesTheremoval of water molecules observed in the range of 150ndash200∘C (found 559ndash608 calc 545ndash551) of all the metalchelates is due to the elimination of two coordinated watermolecules These observations further confirm the distortedoctahedral geometry of BEF metal complexes
The thermogravimetric curves of all the BEF metalchelates showed two degradation steps after loss of watermolecules whichmay indicate that the first step (200ndash600∘C)is faster than the second step (600ndash860∘C) This may bedue to the fact that the noncoordinated part of the liganddecomposes firstwhile the coordinated part decomposes laterand finally it may form the representative metal oxides Theweight of the residues confirms fairly well that ofmetal oxides(found 1247ndash1362 calc 1143ndash1232)
The thermal degradation data of the BEF terpolymerand its metal complexes reveal that the polymeric complexesshow better stability than the BEF terpolymer due to thecoordination of metal ions The order of thermal stability ofthe BEF polymer and its complexes is BEFndashCu2+ gt BEFndashZn2+ gt BEF ligand gt BEFndashNi2+ The greater stability of themetal complexes may be due to the coordination and theenhanced cross linking nature with crowd effect of the metal
complexes [31] In the case of Ni2+ complex the degradationoccurred exceptionally at low temperature compared to theirligand which may be due to the oxidation of polymer by thecatalytic action of the metal ion [32]
383 Thermal Kinetics
(1) Sharp-Wentworth and Freeman-Carroll Method Ther-mal kinetic analysis was performed using Sharp-Wentworthmethod and Freeman-Carroll methods The activationenergy (119864
119886) and order of reaction (119899) plots for BEF terpoly-
mer ligand and its metal complexes by Sharp-Wentworthand Freeman-Carroll methods are shown in Figures 10 11and 12 The expressions used to calculate the kinetic andthermodynamic parameters are presented as follows
(i) Entropy change (Δ119878)
Intercept = log 119870119877
ℎΦ119864119886
+Δ119878
2303119877 (2)
where 119870 = 13806 times 10minus16 ergdegmole 119877 =
1987 caldegmole (8314 JKMol) ℎ = 6625 times
10minus27 erg sec Φ = 0166 Δ119878 = change in entropyand 119864
119886= activation energy from graph
(ii) Free energy change (Δ119865)
Δ119865 = Δ119867 minus 119879Δ119878 (3)
where Δ119867 = enthalpy change = activation energy 119879 =temperature in119870 and Δ119878 = result from (2)
(iii) Frequency factor (119885)
11986123
=log119885119864
119886
119877Φ (4)
11986123
= log 3 + log [1 minus 3radic1 minus 120572] minus log119901 (119909) (5)
where 119885 is the frequency factor 119861 is calculatedfrom (5) log119901(119909) is calculated from Doylersquos tablecorresponding to activation energy and 120572 is degreeof transformation (120572 = 119908119882
119888)
(iv) Apparent entropy (119878lowast)
119878lowast= 2303 log 119885ℎ
119877119879lowast (6)
where119885 is calculated from (4) and 119879lowast is half decom-position temperature
Bioinorganic Chemistry and Applications 11
1000T (Kminus1)
Intercept = minus535
minus45
minus50
minus55
minus60
minus65
minus70
minus75
minus80
10 15 20 25 30
Ea = 952
log[
(dC
dT
)(1
minusC
)]
(a)
minus64
minus62
minus60
minus58
minus56
minus54
minus52
1000T (Kminus1)10 15 20 25 30
Intercept = minus527
Ea = 1297
log[
(dC
dT
)(1
minusC
)]
(b)
minus64
minus62
minus50
minus52
minus54
minus56
minus58
minus60
1000T (Kminus1)10 15 20 25 30
Intercept = minus513
Ea = 693
log[
(dC
dT
)(1
minusC
)]
(c)
minus50
minus51
minus52
minus53
minus54
minus55
minus56
minus57
minus58
minus59
1000T (Kminus1)10 15 20 25 30
Intercept = minus538
Ea = 1108
log[
(dC
dT
)(1
minusC
)]
(d)
Figure 10 Sharp-Wentworth plots of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Table 5 Kinetic and thermodynamic parameters data
CompoundActivation energy
(119864119886kJmolminus1) Entropy change
(Δ119878J)Free energy
change (Δ119865kJ)Frequency
factor (119885sminus1)Apparent
entropy (119878lowastJ)Order of
reaction (119899)lowastSW lowastlowastFC
BEF ligand 952 1039 minus15811 5940 1310 minus2295 090BEFminusCu 1297 1367 minus15425 9079 1205 minus2331 104BEFminusNi 693 460 minus16290 7057 1537 minus2294 093BEFminusZn 1108 1213 minus16001 8013 1243 minus2318 102lowastSW Sharp-Wentworth lowastlowastFC Freeman-Carroll
Further from the knowledge of activation energy cal-culated by Freeman-Carroll method it is possible to eval-uate the values of various thermodynamic parameters Theorder of reaction (119899) and activation energy (119864
119886) and the
thermodynamic parameters such as frequency factor (119885)entropy change (Δ119878) free energy change (Δ119865) and apparententropy (119878lowast) are presented inTable 5The119864
119886values calculated
by SW and FC methods are in good agreement with eachother The order of activation energies for BEF ligand andits Cu2+ Ni2+ and Zn2+ complexes is parallel to the orderof their thermal stability [32] The values of thermodynamic
parameters were comparable indicating a common modeof decomposition reaction The abnormal low values offrequency factor (119885) indicate that the decomposition reactionof BEF terpolymer and its metal complexes can be depictedas a slow reaction The order of reactions (119899) of BEF ligandand its metal complexes is found to be 090 104 093 and102 respectively Hence the BEF terpolymer and its mealcomplexes may be following nearly a first order kinetics
(2) Phadnis-Deshpande Method The activation energiescalculated for BEF ligand and its metal complexes using
12 Bioinorganic Chemistry and Applications
minus00012minus00010minus00008minus00006minus00004minus00002minus00000
26242220181614121008060402
log(dWdt)
(1T)
n = 090
logW
r
logWr
(a)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
20
19
18
17
16
15
14
13
12
11
10
log(dWdt)
(1T)
n = 104
logWr
logW
r
(b)
15
16
17
18
19
14
13
12
11
10
09
log(dWdt)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
(1T)
n = 093logW
r
logWr
(c)
15
16
17
18
14
13
12
11
10
log(dWdt)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
(1T)
n = 102
logW
r
logWr
(d)
Figure 11 Freeman-Carroll plots (119899) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Phadnis-Deshpande method are presented in Table 6 Fromthe 119864
119886values it is possible to propose the degradation
reactionmechanism using PDmethod Further the 119864119886values
calculated by PD method are in good agreement with FCand SW methods Based on the closest 119864
119886values calculated
by PD SW and FC methods the Power law mechanismsuits very well for the BEF ligand and BEFndashCu and BEFndashZn metal complexes However BEFndashNi complex follows theBrounshtein-Ginstling 3-dimensional diffusion mechanism
39 Biological Studies
391 Antibacterial Activity To determine the antibacterialactivity of the BEF terpolymer and its Cu2+ Ni2+ andZn2+ complexes the disc diffusion method was used withamoxicillin as the standard antibiotic The prepared com-pounds were tested against Shigella sonnei Escherichia coliKlebsiella species Staphylococcus aureus Bacillus subtilis andSalmonella typhimuriummicroorganisms
Table 7 contains the screening results corresponding tothe polymeric ligand and its metal complexes with fairinhibition of growth against the tested organisms Shigella
sonnei is a nonmotile non-spore-forming and facultativeanaerobic gram-negative bacterium Shigella bacteria multi-ply within colonic epithelial cells and cause mucosal ulcer-ation inflammation bleeding high fever malaise diarrheaand tenesmus The ligand and its metal complexes showeda reasonable activity against the S sonnei species E coliis an aerobic gram-negative and rod shaped bacteriumInfection of E coli can lead to bloody diarrhea and kidneyfailureThe polymeric ligand and its complexes hold amodestactivity against the E coli Klebsiella is a genus of nonmotileand gram-negative bacteria that infects sites such as nasalpassages liver lung urinary tract bloodstream eye boneand joints It causes a wide range of disease states notablypneumonia septicemia soft tissue infections biliary tractinfection infection of the upper and lower respiratory tractand liver abscess The BEF ligand and its metal complexesshowed a reasonable result against the growth of KlebsiellaStaphylococcus aureus a gram-positive and spherical bac-terium leads to life-threatening diseases like pneumoniaosteomyelitis endocarditis and toxic shock syndrome Toxicshock syndrome is characterized by the sudden onset of highfever vomiting diarrhea and muscle aches followed by lowblood pressure (hypotension) which can lead to shock and
Bioinorganic Chemistry and Applications 13
log[g
(120572)T3]
minus95
minus90
minus85
minus80
minus75
10 15 20 25 30
Intercept = minus825
Ea = 1039
1000T (Kminus1)
(a)
log[g
(120572)T3]
minus78
minus80
minus82
minus84
minus86
minus88
minus90
minus92
minus94
minus96
minus76
Intercept = minus805
Ea = 1367
10 15 20 25 30
1000T (Kminus1)
(b)
log[g
(120572)T3]
minus77
minus78
minus79
minus80
minus81
minus82
minus83
minus84
minus85
minus86
minus87
minus88minus89
Intercept = minus849
Ea = 460
10 15 20 25 30
1000T (Kminus1)
(c)
minus78
minus80
minus82
minus84
minus86
minus7610 15 20 25 30
1000T (Kminus1)
log[g
(120572)T3]
Intercept = minus835
Ea = 1213
(d)
Figure 12 Freeman-Carroll plots (119864119886) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Table 6 Activation energies calculated by Phadnis-Deshpande method
Reaction mechanism model Energy of activation (119864119886) (kJmol)
BEF ligand BEFminusCu BEFminusNi BEFminusZnPower law 60932 62642 59691 54312Power law 121864 125284 119382 108625Phase boundary (contracting sphere) 16497 16816 16174 15009Phase boundary (contracting cylinder) 25894 26436 25383 23466Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 12135 13830 11756 07447
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 08090 09220 07837 04964
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 06067 06915 05878 03723
Valensi 2-dimensional diffusion 168354 171926 165034 152695Jander 3-dimensional diffusion 32995 33632 32349 30018Brounshtein-Ginstling 3-dimensional diffusion 56520 55015 55669 57981The values indicated in bold are closest to the 119864119886 value estimated by FC and SWmethods
14 Bioinorganic Chemistry and Applications
Table 7 Antibacterial activity of BEF ligand and its complexes
Compound Inhibition zone (mm)S sonnei E coli Klebsiella sp S aureus B subtilis S typhi
BEF ligand 15 13 13 14 15 12BEFndashCu 21 17 17 18 18 18BEFndashNi 18 15 18 17 20 15BEFndashZn 16 15 15 16 17 15Standard 26 28 26 25 27 28Control mdash mdash mdash mdash mdash mdashStandard amoxicillin control DMSO
Table 8 Antifungal activity of BEF ligand and its complexes
Compound Inhibition zone (mm)Aspergillus flavus Aspergillus niger Penicillium species Candida albicans Cryptococcus neoformans Mucorspecies
BEF ligand 14 12 12 13 11 12BEFndashCu 20 18 19 18 15 19BEFndashNi 17 14 17 15 13 13BEFndashZn 15 15 18 17 14 16Standard 20 21 19 21 18 22Control mdash mdash mdash mdash mdash mdashStandard fluconazole control DMSO
death There may be a rash resembling sunburn with peelingof skin The ligand and its complexes showed a humbleactivity against the growth of S aureus Bacillus subtilis arerod-shaped and nonpathogenic gram-positive bacteria TheBEF ligand and complexes showed superb activity againstthe growth of this bacterium Salmonella typhimurium is apathogenic gram-negative bacteria predominately found inthe intestinal lumen When the bacterial cells enter epithelialcells lining the intestine they cause host cell ruffling whichtemporarily damages the microvilli on the surface of the cellThis causes a rush of white blood cells into the mucosa andleads to diarrheaThe ligand and its metal complexes showeda moderate activity against the growth of the typhi species
A comparative account on the effect of antibacterialactivity against the chosen microbes indicates that the ligandand its three metal chelates show reasonable activity againstShigella sonnei (15 21 18 and 16mm) and Bacillus subtilis (1518 20 and 17mm) while the growth of other organisms ismoderately inhibited by the BEF ligand and its Cu2+ Ni2+and Zn2+ chelates The highest antibacterial action (21mm)has been observed for BEFndashCu2+ complex against Shigellasonnei
392 Antifungal Activity The antifungal activity of the BEFligand and its metal complexes has also given interestingresults and the growth inhibitions against the chosen fungalstrains are tabulated in Table 8 All the complexes and theirligand have an excellent activity against Aspergillus flavusa mold type fungal strain which may invade arteries of thelung or brain to cause infections and also produce a toxinAspergillus niger is one of the most common causes for
otomycosis The chelates and the ligand are found to havea reasonable activity for A niger Penicillium species causesinfection in humans and the resulting disease is known gener-ically as penicilliosis The ligand and the metal complexeshave wonderful activity against this species Further BEFndashCucomplex has a superior activity compared to the rest of othercomplexes Candida albicans is a diploid fungus and a causalagent of opportunistic oral and genital infections in humansand also emerged as an important cause of morbidity andmortality in immunocompromised patients The BEF ligandand its chelates possess a modest activity against C albicansover and above the standard Cryptococcus neoformans is anencapsulated yeast-like fungus that can live in both plantsand animals and cause lung infection The terpolymer ligandand its chelates have a fair activity against this fungal strainThe chelate compounds and the ligand havemoderate activityagainst Mucor species a filamentous fungus which causesseptic arthritis renal infections and pulmonary infections
From the antimicrobial results themetal complexes showhigher activity than their ligand which may be stronglydependent on the central metal ions and coordination num-bers metal chelates The higher activity due to the metal ionsshared with the donor atoms (N and S) of the thiazole ring ispresent in the ligand and the 120587-electron delocalization overthe chelate ring This effect increases the lipophilic characterof the metal ion which favors the permeation through thelipoid layers of the bacterial and fungal membranes [33 34]It is perceived that the factors such as solubility conductivitydipole moment and cell permeability may also contributeto the increased activity of the complexes [35 36] Fromthe results of the studies at 500 ppm concentration thecompounds establish better antimicrobial activity Hence it
Bioinorganic Chemistry and Applications 15
is an interesting result that a very low concentration of thecompound namely 500 ppm is enough to bring out aneffective inhibition against the chosen microbes
4 Conclusion
The synthesized 2-amino-6-nitro-benzothiazole-ethylene-diamine-formaldehyde terpolymer has acted as a ligandsuccessfully to form metal complexes The synthesized com-pounds were well characterized by various spectral andphysical analyses The morphological features suggest thatthe complexes are slightly more crystalline in nature thantheir parent ligandThe antibacterial and antifungal activitiesreveal that the terpolymer and its metal complexes can beactive against the selected bacterial and fungal strains Nearlyall of the compoundsmay suit well for drug delivery field afterchecking for their toxicology behaviour in thorough mannerThermal studies are also helpful to realize the standing capac-ity of the compounds which survive as antimicrobial coatingmaterials in various environmental conditions Because ofthe proven high stability nature and microbial preventioncapacity the BEF terpolymer and its Cu2+ Ni2+ and Zn2+complexes hold inadequate applications in biological fieldThe thermal stability of the terpolymer and its metal com-plexes was found greater From the thermodynamic andkinetic studies the abnormal low values of frequency factor(119885) indicate that the thermal decomposition reaction of BEFterpolymer and its metal complexes can be depicted as a slowreaction The BEF terpolymer and its metal complexes maybe following nearly a first order kinetics
Conflict of Interests
The authors certify that there is no conflict of interests withany financial organization regarding thematerial discussed inthe paper
Acknowledgments
The authors thank the Management and Principal ofOxford Engineering College Tiruchirappalli CoimbatoreInstitute of Technology Coimbatore Jamal Mohamed Col-lege (Autonomous) Tiruchirappalli Tamil Nadu and DrD Jeyakumar Scientist Central Electrochemical ResearchInstitute (CECRI-CSIR) Karaikudi Tamil Nadu for theirsupport and encouragement
References
[1] C U Pittman K S Ramachandran Jr and K R LowyerldquoSynthesis of fungicidal monomers polymers and latticesrdquoJournal of Coating Technology vol 54 pp 27ndash40 1982
[2] M N Patel J R Patel and D H Sutaria ldquoNovel co-ordinationpolychelatesrdquo Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry vol 24 no 8 pp 1297ndash1309 1994
[3] V V Ukey and H D Juneja ldquoSynthetic and spectroscopicstudies of chelate polymers involving azelaoyl bis-N-phenylhydroxamic acid with transition metal ionsrdquo Journal of AppliedPolymer Science vol 99 no 1 pp 273ndash278 2006
[4] S K-H Thiele and D R Wilson ldquoAlternate transition metalcomplex based diene polymerizationrdquo Polymer Reviews vol 43no 4 pp 581ndash628 2003
[5] N Nishat S Ahmad and T Ahamad ldquoSynthesis and character-ization of antibacterial polychelates of urea-formaldehyde resinwith Cr(III) Mn(II) Fe(III) Co(II) Ni(II) Cu(II) and Zn(II)metal ionsrdquo Journal of Applied Polymer Science vol 100 no 2pp 928ndash936 2006
[6] E Brzezinska G Koska and K Walczynski ldquoApplicationof thin-layer chromatographic data in quantitative structure-activity relationship assay of thiazole and benzothiazole deriva-tives with Hmdashantihistamine activityrdquo Journal of Chromatogra-phy A vol 1007 pp 145ndash155 2003
[7] M A R Ahamed and A R Burkanudeen ldquoMetal complexesof a novel terpolymer ligand synthesis spectral morphologythermal degradation kinetics and antimicrobial screeningrdquoJournal of Inorganic andOrganometallic Polymers andMaterialsvol 22 no 5 pp 1046ndash1061 2012
[8] B S Holla K V Malini V S Rao B K Sarojini and N SKumari ldquoSynthesis of some new 24-disubstituted thiazoles aspossible antibacterial and anti-inflammatory agentsrdquo EuropeanJournal of Medicinal Chemistry vol 38 no 3 pp 313ndash318 2003
[9] O I El-Sabbagh M M Baraka S M Ibrahim et al ldquoSynthesisand antiviral activity of new pyrazole and thiazole derivativesrdquoEuropean Journal of Medicinal Chemistry vol 44 no 9 pp3746ndash3753 2009
[10] A Andreani M Granaiola A Leoni A Locatelli R Morigiand M Rambaldi ldquoSynthesis and antitubercular activity ofimidazo[21-b]thiazolesrdquo European Journal of Medicinal Chem-istry vol 36 no 9 pp 743ndash746 2001
[11] E Yousif Y Farina K Kasar A Graisa and K Ayid ldquoCom-plexes of 2-thioacetic acid benzothiazole with somemetal ionsrdquoAmerican Journal of Applied Sciences vol 6 no 4 pp 582ndash5852009
[12] B P Mallikarjuna B S Sastry G V Suresh Kumar Y Rajen-draprasad S M Chandrashekar and K Sathisha ldquoSynthesis ofnew 4-isopropylthiazole hydrazide analogs and some derivedclubbed triazole oxadiazole ring systemsmdasha novel class ofpotential antibacterial antifungal and antitubercular agentsrdquoEuropean Journal of Medicinal Chemistry vol 44 pp 4739ndash4746 2009
[13] T Ahamad V Kumar and N Nishat ldquoNew class of anti-microbial agents synthesis characterization and anti-microbial activities of metal chelated polyureardquo Journal ofBiomedical Materials Research A vol 88 no 2 pp 288ndash2942009
[14] M V Patel J N Patel M B Dolia and R M Patel ldquoPolyether-ketones synthesis characterization and antimicrobial activityrdquoInternational Journal of Polymeric Materials and PolymericBiomaterials vol 54 no 11 pp 1059ndash1071 2005
[15] K R Alagawadi and S G Alegaon ldquoSynthesis characteriza-tion and antimicrobial activity evaluation of new 24-Thiazoli-dinediones bearing imidazo[21-b][134]thiadiazole moietyrdquoArabian Journal of Chemistry vol 4 no 4 pp 465ndash472 2011
[16] M Ashok B S Holla and N S Kumari ldquoConvenientone pot synthesis of some novel derivatives of thiazolo[23-b]dihydropyrimidinone possessing 4-methylthiophenyl moietyand evaluation of their antibacterial and antifungal activitiesrdquoEuropean Journal ofMedicinal Chemistry vol 42 no 3 pp 380ndash385 2007
16 Bioinorganic Chemistry and Applications
[17] T Ahamad V Kumar S Parveen and N Nishat ldquoIn vitroantibacterial and antifungal assay of poly-(ethylene oxamide-NN1015840-diacetate) and its polymer-metal complexesrdquo AppliedOrganometallic Chemistry vol 21 no 12 pp 1013ndash1021 2007
[18] R S Azarudeen M A R Ahamed and A R BurkanudeenldquoBiological and thermal investigations of polychelates derivedfrom a novel terpolymer ligandrdquo Journal of Polymer Researchvol 18 no 6 pp 1331ndash1341 2011
[19] R S Azarudeen and A R Burkanudeen ldquoSynthesis spectralmorphology thermal degradation kinetics and antibacterialstudies of terpolymermetal complexesrdquo Journal of Inorganic andOrganometallic Polymers and Materials vol 22 no 4 pp 791ndash806 2012
[20] R S Azarudeen and A R Burkanudeen ldquoStudies of newoligomer-metal complexes and their antibacterial activitiesrdquoPolymer International vol 62 no 3 pp 362ndash374 2013
[21] G S Devi A K Muthu D S Kumar S Rekha R Indhumathiand R Nandhini ldquoStudies on the antibacterial and antifungalactivities of the ethanolic extracts of Luffa cylindrica (Linn)fruitrdquo International Journal of Drug Development and Researchvol 1 pp 105ndash109 2013
[22] R M Silverstein and G C Bassler Spectrometric IdentificationofOrganic Compounds JohnWileyamp SonsNewYorkNYUSA2nd edition 1967
[23] Y-G Zhao H-Y Shen S-D Pan and M-Q Hu ldquoSyn-thesis characterization and properties of ethylenediamine-functionalized Fe
3O4magnetic polymers for removal of Cr(VI)
in wastewaterrdquo Journal of Hazardous Materials vol 182 no 1-3pp 295ndash302 2010
[24] Y R Sharma Elementary Organic Absorption Spectroscopy SChand amp Co Ltd New Delhi India 1980
[25] D Kivelson and R Neiman ldquoESR line shapes in glasses ofcopper complexesrdquoThe Journal of Chemical Physics vol 35 no1 pp 149ndash155 1961
[26] E Pretsch P Buhlmann and C Afflolter Structure Determi-nation of Organic Compounds Springer New York NY USA2000
[27] J L White Modern Magnetic Resonance Kluwer AcademicPress London UK 2006
[28] M M Patel M A Kapadia and J D Joshi ldquoThermal andcatalytic aspects of Ln(III) polymer-metal complexesrdquo PolymerInternational vol 58 no 7 pp 728ndash737 2009
[29] S Nanjundan C S J Selvamalar and R Jayakumar ldquoSynthesisand characterization of poly(3-acetyl-4-hydroxyphenyl acry-late) and its Cu(II) and Ni(II) complexesrdquo European PolymerJournal vol 40 no 10 pp 2313ndash2321 2004
[30] A V Nikolaev V A Logvinenco and L I Myachina ThermalAnalysis Academic Press New York NY USA 1969
[31] A Z El-Sonbati and M A Hefni ldquoPolymer complexes PartXXVImdashNovel mixed ligand poly-(5-vinyl salicylidene)-12-diaminobenzene complexesrdquo Polymer Degradation and Stabil-ity vol 43 no 1 pp 33ndash42 1994
[32] A S Aswar and N S Bhave ldquoThermal degradation studies ofsome new coordination polymersrdquo Polymer Degradation andStability vol 31 no 1 pp 115ndash124 1991
[33] T Ahamad V Kumar and N Nishat ldquoSynthesis characteri-zation and antimicrobial activity of transition metal chelatedthiourea-formaldehyde resinrdquo Polymer International vol 55no 12 pp 1398ndash1406 2006
[34] M M Patel M A Kapadia G P Patel and J D Joshi ldquoSynthe-sis characterization ion-exchange and antimicrobial study of
poly[(2-hydroxy-4-methoxybenzophenone) propylene] resinand its polychelates with lanthanides (III)rdquo Journal of AppliedPolymer Science vol 106 no 2 pp 1307ndash1317 2007
[35] M A Neelakantan S S Marriappan J Dharmaraja T Jeyaku-mar and K Muthukumaran ldquoSpectral XRD SEM and bio-logical activities of transition metal complexes of polydentateligands containing thiazole moietyrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 71 no 2 pp 628ndash635 2008
[36] G B Bagihalli S A Patil and P S Badami ldquoSynthesisphysicochemical investigation and biological studies of zinc(II)complexes with 124-triazole schiff basesrdquo Journal of the IranianChemical Society vol 6 no 2 pp 259ndash270 2009
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Inorganic ChemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Carbohydrate Chemistry
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
Physical Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom
Analytical Methods in Chemistry
Journal of
Volume 2014
Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
SpectroscopyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Medicinal ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chromatography Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Applied ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Theoretical ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Spectroscopy
Analytical ChemistryInternational Journal of
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Quantum Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Organic Chemistry International
ElectrochemistryInternational Journal of
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CatalystsJournal of
Bioinorganic Chemistry and Applications 9
Inte
nsity
(au
)
0 20 40 60 802120579
(a)
Inte
nsity
(au
)
0 20 40 60 802120579
(b)
Inte
nsity
(au
)
0 20 40 60 802120579
(c)
Inte
nsity
(au
)
0 20 40 60 802120579
(d)
Figure 8 XRD patterns of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
the cooperative contribution of the ligand for complexationwith metal ions or the disappearance of the voids in therearrangement of polymer chains for complexation withmetal ions This is a further evidence for the complexationof BEF terpolymer with metal ions
37 XRD Studies X-ray diffraction (XRD) patterns of BEFand its metal complexes are shown in Figure 8 It provides adetailed comparative account of the behavior of the terpoly-mer and itsmetal complexesThepattern of BEF ligand showsthe main characteristic peak and broad shoulder In view ofthe relative half value width it may be concluded that thepolymer is partially crystalline and the broad characteristicpeak indicates the amorphous nature of the terpolymerTherefore the BEF terpolymer has transition state betweenamorphous state and crystalline state whereas its metalchelates possess crystalline nature The enhanced crystallinebehavior of the BEF complexes may be due to the insertion ofmetal ions with their parent ligand [29]
38 Thermal Stability Thermal stability of the BEF terpoly-mer and its metal complexes was analyzed by thermogravi-metric analysis (TGA) The thermograms of the terpolymer
and its metal complexes are shown in Figure 9 and their per-centages of weight loss at various temperatures are presentedin Table 4
381Thermal Stability of BEF Terpolymer From the thermo-gram of BEF terpolymer there were three stages of degra-dation (200ndash320∘C 320ndash580∘C and 580ndash835∘C) observedThe first stage of degradation was observed between 200∘Cand 320∘C (found 5883 calc 5794) which reveals thedegradation of the benzothiazole ring The second stageof degradation begins at 320∘C and ends at 580∘C (found1003 calc 0931) which may be due to the eliminationof cross-linkages The third and final stage of degradation isobserved above 580∘C and continued up to 825∘C (found2506 calc 2473) which can be attributed to the weightloss of aliphatic group (ethylenediamine moiety) from theBEF terpolymer
382 Thermal Stability of BEF Metal Complexes In generalthe water of hydration may be considered as either crystalwater molecules or coordination water molecules Accordingto Nikolaev et al [30] water eliminated below 150∘C can beconsidered as crystal or lattice water and water eliminated
10 Bioinorganic Chemistry and Applications
Table 4 TGA data for thermal stability
Compound Percentage of weight loss at various temperatures11987950
lowast (∘C) 119879maxlowastlowast (∘C)
100 200 300 400 500 600 700 800 (∘C)BEF ligand 0153 0365 4414 6236 6718 7140 8224 9442 310 825BEFminusCu 0194 1432 3180 4301 4996 5549 6686 8122 500 860BEFminusNi 0893 1660 3735 4935 6460 8767 mdash mdash 405 650BEFminusZn 1464 2262 3833 4616 5726 6492 7614 9129 425 830lowastTemperature of 50 weight loss lowastlowastmaximum decomposition temperature
80
60
40
20
0
0
(a)(b)
(c)(d)
200 400 600 800 1000
100
Wei
ght (
)
Temperature (∘C)
Figure 9 TGA of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d)BEFndashZn
above 150∘C may be due to its coordination to the metalatom present in chelates In the present study in the case ofBEFndashCu2+ Ni2+ and Zn2+ complexes the removal of waterfrom the complex was completed within 150∘C These watermolecules are probably crystal or lattice water moleculesTheremoval of water molecules observed in the range of 150ndash200∘C (found 559ndash608 calc 545ndash551) of all the metalchelates is due to the elimination of two coordinated watermolecules These observations further confirm the distortedoctahedral geometry of BEF metal complexes
The thermogravimetric curves of all the BEF metalchelates showed two degradation steps after loss of watermolecules whichmay indicate that the first step (200ndash600∘C)is faster than the second step (600ndash860∘C) This may bedue to the fact that the noncoordinated part of the liganddecomposes firstwhile the coordinated part decomposes laterand finally it may form the representative metal oxides Theweight of the residues confirms fairly well that ofmetal oxides(found 1247ndash1362 calc 1143ndash1232)
The thermal degradation data of the BEF terpolymerand its metal complexes reveal that the polymeric complexesshow better stability than the BEF terpolymer due to thecoordination of metal ions The order of thermal stability ofthe BEF polymer and its complexes is BEFndashCu2+ gt BEFndashZn2+ gt BEF ligand gt BEFndashNi2+ The greater stability of themetal complexes may be due to the coordination and theenhanced cross linking nature with crowd effect of the metal
complexes [31] In the case of Ni2+ complex the degradationoccurred exceptionally at low temperature compared to theirligand which may be due to the oxidation of polymer by thecatalytic action of the metal ion [32]
383 Thermal Kinetics
(1) Sharp-Wentworth and Freeman-Carroll Method Ther-mal kinetic analysis was performed using Sharp-Wentworthmethod and Freeman-Carroll methods The activationenergy (119864
119886) and order of reaction (119899) plots for BEF terpoly-
mer ligand and its metal complexes by Sharp-Wentworthand Freeman-Carroll methods are shown in Figures 10 11and 12 The expressions used to calculate the kinetic andthermodynamic parameters are presented as follows
(i) Entropy change (Δ119878)
Intercept = log 119870119877
ℎΦ119864119886
+Δ119878
2303119877 (2)
where 119870 = 13806 times 10minus16 ergdegmole 119877 =
1987 caldegmole (8314 JKMol) ℎ = 6625 times
10minus27 erg sec Φ = 0166 Δ119878 = change in entropyand 119864
119886= activation energy from graph
(ii) Free energy change (Δ119865)
Δ119865 = Δ119867 minus 119879Δ119878 (3)
where Δ119867 = enthalpy change = activation energy 119879 =temperature in119870 and Δ119878 = result from (2)
(iii) Frequency factor (119885)
11986123
=log119885119864
119886
119877Φ (4)
11986123
= log 3 + log [1 minus 3radic1 minus 120572] minus log119901 (119909) (5)
where 119885 is the frequency factor 119861 is calculatedfrom (5) log119901(119909) is calculated from Doylersquos tablecorresponding to activation energy and 120572 is degreeof transformation (120572 = 119908119882
119888)
(iv) Apparent entropy (119878lowast)
119878lowast= 2303 log 119885ℎ
119877119879lowast (6)
where119885 is calculated from (4) and 119879lowast is half decom-position temperature
Bioinorganic Chemistry and Applications 11
1000T (Kminus1)
Intercept = minus535
minus45
minus50
minus55
minus60
minus65
minus70
minus75
minus80
10 15 20 25 30
Ea = 952
log[
(dC
dT
)(1
minusC
)]
(a)
minus64
minus62
minus60
minus58
minus56
minus54
minus52
1000T (Kminus1)10 15 20 25 30
Intercept = minus527
Ea = 1297
log[
(dC
dT
)(1
minusC
)]
(b)
minus64
minus62
minus50
minus52
minus54
minus56
minus58
minus60
1000T (Kminus1)10 15 20 25 30
Intercept = minus513
Ea = 693
log[
(dC
dT
)(1
minusC
)]
(c)
minus50
minus51
minus52
minus53
minus54
minus55
minus56
minus57
minus58
minus59
1000T (Kminus1)10 15 20 25 30
Intercept = minus538
Ea = 1108
log[
(dC
dT
)(1
minusC
)]
(d)
Figure 10 Sharp-Wentworth plots of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Table 5 Kinetic and thermodynamic parameters data
CompoundActivation energy
(119864119886kJmolminus1) Entropy change
(Δ119878J)Free energy
change (Δ119865kJ)Frequency
factor (119885sminus1)Apparent
entropy (119878lowastJ)Order of
reaction (119899)lowastSW lowastlowastFC
BEF ligand 952 1039 minus15811 5940 1310 minus2295 090BEFminusCu 1297 1367 minus15425 9079 1205 minus2331 104BEFminusNi 693 460 minus16290 7057 1537 minus2294 093BEFminusZn 1108 1213 minus16001 8013 1243 minus2318 102lowastSW Sharp-Wentworth lowastlowastFC Freeman-Carroll
Further from the knowledge of activation energy cal-culated by Freeman-Carroll method it is possible to eval-uate the values of various thermodynamic parameters Theorder of reaction (119899) and activation energy (119864
119886) and the
thermodynamic parameters such as frequency factor (119885)entropy change (Δ119878) free energy change (Δ119865) and apparententropy (119878lowast) are presented inTable 5The119864
119886values calculated
by SW and FC methods are in good agreement with eachother The order of activation energies for BEF ligand andits Cu2+ Ni2+ and Zn2+ complexes is parallel to the orderof their thermal stability [32] The values of thermodynamic
parameters were comparable indicating a common modeof decomposition reaction The abnormal low values offrequency factor (119885) indicate that the decomposition reactionof BEF terpolymer and its metal complexes can be depictedas a slow reaction The order of reactions (119899) of BEF ligandand its metal complexes is found to be 090 104 093 and102 respectively Hence the BEF terpolymer and its mealcomplexes may be following nearly a first order kinetics
(2) Phadnis-Deshpande Method The activation energiescalculated for BEF ligand and its metal complexes using
12 Bioinorganic Chemistry and Applications
minus00012minus00010minus00008minus00006minus00004minus00002minus00000
26242220181614121008060402
log(dWdt)
(1T)
n = 090
logW
r
logWr
(a)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
20
19
18
17
16
15
14
13
12
11
10
log(dWdt)
(1T)
n = 104
logWr
logW
r
(b)
15
16
17
18
19
14
13
12
11
10
09
log(dWdt)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
(1T)
n = 093logW
r
logWr
(c)
15
16
17
18
14
13
12
11
10
log(dWdt)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
(1T)
n = 102
logW
r
logWr
(d)
Figure 11 Freeman-Carroll plots (119899) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Phadnis-Deshpande method are presented in Table 6 Fromthe 119864
119886values it is possible to propose the degradation
reactionmechanism using PDmethod Further the 119864119886values
calculated by PD method are in good agreement with FCand SW methods Based on the closest 119864
119886values calculated
by PD SW and FC methods the Power law mechanismsuits very well for the BEF ligand and BEFndashCu and BEFndashZn metal complexes However BEFndashNi complex follows theBrounshtein-Ginstling 3-dimensional diffusion mechanism
39 Biological Studies
391 Antibacterial Activity To determine the antibacterialactivity of the BEF terpolymer and its Cu2+ Ni2+ andZn2+ complexes the disc diffusion method was used withamoxicillin as the standard antibiotic The prepared com-pounds were tested against Shigella sonnei Escherichia coliKlebsiella species Staphylococcus aureus Bacillus subtilis andSalmonella typhimuriummicroorganisms
Table 7 contains the screening results corresponding tothe polymeric ligand and its metal complexes with fairinhibition of growth against the tested organisms Shigella
sonnei is a nonmotile non-spore-forming and facultativeanaerobic gram-negative bacterium Shigella bacteria multi-ply within colonic epithelial cells and cause mucosal ulcer-ation inflammation bleeding high fever malaise diarrheaand tenesmus The ligand and its metal complexes showeda reasonable activity against the S sonnei species E coliis an aerobic gram-negative and rod shaped bacteriumInfection of E coli can lead to bloody diarrhea and kidneyfailureThe polymeric ligand and its complexes hold amodestactivity against the E coli Klebsiella is a genus of nonmotileand gram-negative bacteria that infects sites such as nasalpassages liver lung urinary tract bloodstream eye boneand joints It causes a wide range of disease states notablypneumonia septicemia soft tissue infections biliary tractinfection infection of the upper and lower respiratory tractand liver abscess The BEF ligand and its metal complexesshowed a reasonable result against the growth of KlebsiellaStaphylococcus aureus a gram-positive and spherical bac-terium leads to life-threatening diseases like pneumoniaosteomyelitis endocarditis and toxic shock syndrome Toxicshock syndrome is characterized by the sudden onset of highfever vomiting diarrhea and muscle aches followed by lowblood pressure (hypotension) which can lead to shock and
Bioinorganic Chemistry and Applications 13
log[g
(120572)T3]
minus95
minus90
minus85
minus80
minus75
10 15 20 25 30
Intercept = minus825
Ea = 1039
1000T (Kminus1)
(a)
log[g
(120572)T3]
minus78
minus80
minus82
minus84
minus86
minus88
minus90
minus92
minus94
minus96
minus76
Intercept = minus805
Ea = 1367
10 15 20 25 30
1000T (Kminus1)
(b)
log[g
(120572)T3]
minus77
minus78
minus79
minus80
minus81
minus82
minus83
minus84
minus85
minus86
minus87
minus88minus89
Intercept = minus849
Ea = 460
10 15 20 25 30
1000T (Kminus1)
(c)
minus78
minus80
minus82
minus84
minus86
minus7610 15 20 25 30
1000T (Kminus1)
log[g
(120572)T3]
Intercept = minus835
Ea = 1213
(d)
Figure 12 Freeman-Carroll plots (119864119886) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Table 6 Activation energies calculated by Phadnis-Deshpande method
Reaction mechanism model Energy of activation (119864119886) (kJmol)
BEF ligand BEFminusCu BEFminusNi BEFminusZnPower law 60932 62642 59691 54312Power law 121864 125284 119382 108625Phase boundary (contracting sphere) 16497 16816 16174 15009Phase boundary (contracting cylinder) 25894 26436 25383 23466Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 12135 13830 11756 07447
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 08090 09220 07837 04964
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 06067 06915 05878 03723
Valensi 2-dimensional diffusion 168354 171926 165034 152695Jander 3-dimensional diffusion 32995 33632 32349 30018Brounshtein-Ginstling 3-dimensional diffusion 56520 55015 55669 57981The values indicated in bold are closest to the 119864119886 value estimated by FC and SWmethods
14 Bioinorganic Chemistry and Applications
Table 7 Antibacterial activity of BEF ligand and its complexes
Compound Inhibition zone (mm)S sonnei E coli Klebsiella sp S aureus B subtilis S typhi
BEF ligand 15 13 13 14 15 12BEFndashCu 21 17 17 18 18 18BEFndashNi 18 15 18 17 20 15BEFndashZn 16 15 15 16 17 15Standard 26 28 26 25 27 28Control mdash mdash mdash mdash mdash mdashStandard amoxicillin control DMSO
Table 8 Antifungal activity of BEF ligand and its complexes
Compound Inhibition zone (mm)Aspergillus flavus Aspergillus niger Penicillium species Candida albicans Cryptococcus neoformans Mucorspecies
BEF ligand 14 12 12 13 11 12BEFndashCu 20 18 19 18 15 19BEFndashNi 17 14 17 15 13 13BEFndashZn 15 15 18 17 14 16Standard 20 21 19 21 18 22Control mdash mdash mdash mdash mdash mdashStandard fluconazole control DMSO
death There may be a rash resembling sunburn with peelingof skin The ligand and its complexes showed a humbleactivity against the growth of S aureus Bacillus subtilis arerod-shaped and nonpathogenic gram-positive bacteria TheBEF ligand and complexes showed superb activity againstthe growth of this bacterium Salmonella typhimurium is apathogenic gram-negative bacteria predominately found inthe intestinal lumen When the bacterial cells enter epithelialcells lining the intestine they cause host cell ruffling whichtemporarily damages the microvilli on the surface of the cellThis causes a rush of white blood cells into the mucosa andleads to diarrheaThe ligand and its metal complexes showeda moderate activity against the growth of the typhi species
A comparative account on the effect of antibacterialactivity against the chosen microbes indicates that the ligandand its three metal chelates show reasonable activity againstShigella sonnei (15 21 18 and 16mm) and Bacillus subtilis (1518 20 and 17mm) while the growth of other organisms ismoderately inhibited by the BEF ligand and its Cu2+ Ni2+and Zn2+ chelates The highest antibacterial action (21mm)has been observed for BEFndashCu2+ complex against Shigellasonnei
392 Antifungal Activity The antifungal activity of the BEFligand and its metal complexes has also given interestingresults and the growth inhibitions against the chosen fungalstrains are tabulated in Table 8 All the complexes and theirligand have an excellent activity against Aspergillus flavusa mold type fungal strain which may invade arteries of thelung or brain to cause infections and also produce a toxinAspergillus niger is one of the most common causes for
otomycosis The chelates and the ligand are found to havea reasonable activity for A niger Penicillium species causesinfection in humans and the resulting disease is known gener-ically as penicilliosis The ligand and the metal complexeshave wonderful activity against this species Further BEFndashCucomplex has a superior activity compared to the rest of othercomplexes Candida albicans is a diploid fungus and a causalagent of opportunistic oral and genital infections in humansand also emerged as an important cause of morbidity andmortality in immunocompromised patients The BEF ligandand its chelates possess a modest activity against C albicansover and above the standard Cryptococcus neoformans is anencapsulated yeast-like fungus that can live in both plantsand animals and cause lung infection The terpolymer ligandand its chelates have a fair activity against this fungal strainThe chelate compounds and the ligand havemoderate activityagainst Mucor species a filamentous fungus which causesseptic arthritis renal infections and pulmonary infections
From the antimicrobial results themetal complexes showhigher activity than their ligand which may be stronglydependent on the central metal ions and coordination num-bers metal chelates The higher activity due to the metal ionsshared with the donor atoms (N and S) of the thiazole ring ispresent in the ligand and the 120587-electron delocalization overthe chelate ring This effect increases the lipophilic characterof the metal ion which favors the permeation through thelipoid layers of the bacterial and fungal membranes [33 34]It is perceived that the factors such as solubility conductivitydipole moment and cell permeability may also contributeto the increased activity of the complexes [35 36] Fromthe results of the studies at 500 ppm concentration thecompounds establish better antimicrobial activity Hence it
Bioinorganic Chemistry and Applications 15
is an interesting result that a very low concentration of thecompound namely 500 ppm is enough to bring out aneffective inhibition against the chosen microbes
4 Conclusion
The synthesized 2-amino-6-nitro-benzothiazole-ethylene-diamine-formaldehyde terpolymer has acted as a ligandsuccessfully to form metal complexes The synthesized com-pounds were well characterized by various spectral andphysical analyses The morphological features suggest thatthe complexes are slightly more crystalline in nature thantheir parent ligandThe antibacterial and antifungal activitiesreveal that the terpolymer and its metal complexes can beactive against the selected bacterial and fungal strains Nearlyall of the compoundsmay suit well for drug delivery field afterchecking for their toxicology behaviour in thorough mannerThermal studies are also helpful to realize the standing capac-ity of the compounds which survive as antimicrobial coatingmaterials in various environmental conditions Because ofthe proven high stability nature and microbial preventioncapacity the BEF terpolymer and its Cu2+ Ni2+ and Zn2+complexes hold inadequate applications in biological fieldThe thermal stability of the terpolymer and its metal com-plexes was found greater From the thermodynamic andkinetic studies the abnormal low values of frequency factor(119885) indicate that the thermal decomposition reaction of BEFterpolymer and its metal complexes can be depicted as a slowreaction The BEF terpolymer and its metal complexes maybe following nearly a first order kinetics
Conflict of Interests
The authors certify that there is no conflict of interests withany financial organization regarding thematerial discussed inthe paper
Acknowledgments
The authors thank the Management and Principal ofOxford Engineering College Tiruchirappalli CoimbatoreInstitute of Technology Coimbatore Jamal Mohamed Col-lege (Autonomous) Tiruchirappalli Tamil Nadu and DrD Jeyakumar Scientist Central Electrochemical ResearchInstitute (CECRI-CSIR) Karaikudi Tamil Nadu for theirsupport and encouragement
References
[1] C U Pittman K S Ramachandran Jr and K R LowyerldquoSynthesis of fungicidal monomers polymers and latticesrdquoJournal of Coating Technology vol 54 pp 27ndash40 1982
[2] M N Patel J R Patel and D H Sutaria ldquoNovel co-ordinationpolychelatesrdquo Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry vol 24 no 8 pp 1297ndash1309 1994
[3] V V Ukey and H D Juneja ldquoSynthetic and spectroscopicstudies of chelate polymers involving azelaoyl bis-N-phenylhydroxamic acid with transition metal ionsrdquo Journal of AppliedPolymer Science vol 99 no 1 pp 273ndash278 2006
[4] S K-H Thiele and D R Wilson ldquoAlternate transition metalcomplex based diene polymerizationrdquo Polymer Reviews vol 43no 4 pp 581ndash628 2003
[5] N Nishat S Ahmad and T Ahamad ldquoSynthesis and character-ization of antibacterial polychelates of urea-formaldehyde resinwith Cr(III) Mn(II) Fe(III) Co(II) Ni(II) Cu(II) and Zn(II)metal ionsrdquo Journal of Applied Polymer Science vol 100 no 2pp 928ndash936 2006
[6] E Brzezinska G Koska and K Walczynski ldquoApplicationof thin-layer chromatographic data in quantitative structure-activity relationship assay of thiazole and benzothiazole deriva-tives with Hmdashantihistamine activityrdquo Journal of Chromatogra-phy A vol 1007 pp 145ndash155 2003
[7] M A R Ahamed and A R Burkanudeen ldquoMetal complexesof a novel terpolymer ligand synthesis spectral morphologythermal degradation kinetics and antimicrobial screeningrdquoJournal of Inorganic andOrganometallic Polymers andMaterialsvol 22 no 5 pp 1046ndash1061 2012
[8] B S Holla K V Malini V S Rao B K Sarojini and N SKumari ldquoSynthesis of some new 24-disubstituted thiazoles aspossible antibacterial and anti-inflammatory agentsrdquo EuropeanJournal of Medicinal Chemistry vol 38 no 3 pp 313ndash318 2003
[9] O I El-Sabbagh M M Baraka S M Ibrahim et al ldquoSynthesisand antiviral activity of new pyrazole and thiazole derivativesrdquoEuropean Journal of Medicinal Chemistry vol 44 no 9 pp3746ndash3753 2009
[10] A Andreani M Granaiola A Leoni A Locatelli R Morigiand M Rambaldi ldquoSynthesis and antitubercular activity ofimidazo[21-b]thiazolesrdquo European Journal of Medicinal Chem-istry vol 36 no 9 pp 743ndash746 2001
[11] E Yousif Y Farina K Kasar A Graisa and K Ayid ldquoCom-plexes of 2-thioacetic acid benzothiazole with somemetal ionsrdquoAmerican Journal of Applied Sciences vol 6 no 4 pp 582ndash5852009
[12] B P Mallikarjuna B S Sastry G V Suresh Kumar Y Rajen-draprasad S M Chandrashekar and K Sathisha ldquoSynthesis ofnew 4-isopropylthiazole hydrazide analogs and some derivedclubbed triazole oxadiazole ring systemsmdasha novel class ofpotential antibacterial antifungal and antitubercular agentsrdquoEuropean Journal of Medicinal Chemistry vol 44 pp 4739ndash4746 2009
[13] T Ahamad V Kumar and N Nishat ldquoNew class of anti-microbial agents synthesis characterization and anti-microbial activities of metal chelated polyureardquo Journal ofBiomedical Materials Research A vol 88 no 2 pp 288ndash2942009
[14] M V Patel J N Patel M B Dolia and R M Patel ldquoPolyether-ketones synthesis characterization and antimicrobial activityrdquoInternational Journal of Polymeric Materials and PolymericBiomaterials vol 54 no 11 pp 1059ndash1071 2005
[15] K R Alagawadi and S G Alegaon ldquoSynthesis characteriza-tion and antimicrobial activity evaluation of new 24-Thiazoli-dinediones bearing imidazo[21-b][134]thiadiazole moietyrdquoArabian Journal of Chemistry vol 4 no 4 pp 465ndash472 2011
[16] M Ashok B S Holla and N S Kumari ldquoConvenientone pot synthesis of some novel derivatives of thiazolo[23-b]dihydropyrimidinone possessing 4-methylthiophenyl moietyand evaluation of their antibacterial and antifungal activitiesrdquoEuropean Journal ofMedicinal Chemistry vol 42 no 3 pp 380ndash385 2007
16 Bioinorganic Chemistry and Applications
[17] T Ahamad V Kumar S Parveen and N Nishat ldquoIn vitroantibacterial and antifungal assay of poly-(ethylene oxamide-NN1015840-diacetate) and its polymer-metal complexesrdquo AppliedOrganometallic Chemistry vol 21 no 12 pp 1013ndash1021 2007
[18] R S Azarudeen M A R Ahamed and A R BurkanudeenldquoBiological and thermal investigations of polychelates derivedfrom a novel terpolymer ligandrdquo Journal of Polymer Researchvol 18 no 6 pp 1331ndash1341 2011
[19] R S Azarudeen and A R Burkanudeen ldquoSynthesis spectralmorphology thermal degradation kinetics and antibacterialstudies of terpolymermetal complexesrdquo Journal of Inorganic andOrganometallic Polymers and Materials vol 22 no 4 pp 791ndash806 2012
[20] R S Azarudeen and A R Burkanudeen ldquoStudies of newoligomer-metal complexes and their antibacterial activitiesrdquoPolymer International vol 62 no 3 pp 362ndash374 2013
[21] G S Devi A K Muthu D S Kumar S Rekha R Indhumathiand R Nandhini ldquoStudies on the antibacterial and antifungalactivities of the ethanolic extracts of Luffa cylindrica (Linn)fruitrdquo International Journal of Drug Development and Researchvol 1 pp 105ndash109 2013
[22] R M Silverstein and G C Bassler Spectrometric IdentificationofOrganic Compounds JohnWileyamp SonsNewYorkNYUSA2nd edition 1967
[23] Y-G Zhao H-Y Shen S-D Pan and M-Q Hu ldquoSyn-thesis characterization and properties of ethylenediamine-functionalized Fe
3O4magnetic polymers for removal of Cr(VI)
in wastewaterrdquo Journal of Hazardous Materials vol 182 no 1-3pp 295ndash302 2010
[24] Y R Sharma Elementary Organic Absorption Spectroscopy SChand amp Co Ltd New Delhi India 1980
[25] D Kivelson and R Neiman ldquoESR line shapes in glasses ofcopper complexesrdquoThe Journal of Chemical Physics vol 35 no1 pp 149ndash155 1961
[26] E Pretsch P Buhlmann and C Afflolter Structure Determi-nation of Organic Compounds Springer New York NY USA2000
[27] J L White Modern Magnetic Resonance Kluwer AcademicPress London UK 2006
[28] M M Patel M A Kapadia and J D Joshi ldquoThermal andcatalytic aspects of Ln(III) polymer-metal complexesrdquo PolymerInternational vol 58 no 7 pp 728ndash737 2009
[29] S Nanjundan C S J Selvamalar and R Jayakumar ldquoSynthesisand characterization of poly(3-acetyl-4-hydroxyphenyl acry-late) and its Cu(II) and Ni(II) complexesrdquo European PolymerJournal vol 40 no 10 pp 2313ndash2321 2004
[30] A V Nikolaev V A Logvinenco and L I Myachina ThermalAnalysis Academic Press New York NY USA 1969
[31] A Z El-Sonbati and M A Hefni ldquoPolymer complexes PartXXVImdashNovel mixed ligand poly-(5-vinyl salicylidene)-12-diaminobenzene complexesrdquo Polymer Degradation and Stabil-ity vol 43 no 1 pp 33ndash42 1994
[32] A S Aswar and N S Bhave ldquoThermal degradation studies ofsome new coordination polymersrdquo Polymer Degradation andStability vol 31 no 1 pp 115ndash124 1991
[33] T Ahamad V Kumar and N Nishat ldquoSynthesis characteri-zation and antimicrobial activity of transition metal chelatedthiourea-formaldehyde resinrdquo Polymer International vol 55no 12 pp 1398ndash1406 2006
[34] M M Patel M A Kapadia G P Patel and J D Joshi ldquoSynthe-sis characterization ion-exchange and antimicrobial study of
poly[(2-hydroxy-4-methoxybenzophenone) propylene] resinand its polychelates with lanthanides (III)rdquo Journal of AppliedPolymer Science vol 106 no 2 pp 1307ndash1317 2007
[35] M A Neelakantan S S Marriappan J Dharmaraja T Jeyaku-mar and K Muthukumaran ldquoSpectral XRD SEM and bio-logical activities of transition metal complexes of polydentateligands containing thiazole moietyrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 71 no 2 pp 628ndash635 2008
[36] G B Bagihalli S A Patil and P S Badami ldquoSynthesisphysicochemical investigation and biological studies of zinc(II)complexes with 124-triazole schiff basesrdquo Journal of the IranianChemical Society vol 6 no 2 pp 259ndash270 2009
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Inorganic ChemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Carbohydrate Chemistry
International Journal of
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Journal of
Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
Physical Chemistry
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Analytical Methods in Chemistry
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Volume 2014
Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
SpectroscopyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Medicinal ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chromatography Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Applied ChemistryJournal of
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Theoretical ChemistryJournal of
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Journal of
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Analytical ChemistryInternational Journal of
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Quantum Chemistry
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Organic Chemistry International
ElectrochemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CatalystsJournal of
10 Bioinorganic Chemistry and Applications
Table 4 TGA data for thermal stability
Compound Percentage of weight loss at various temperatures11987950
lowast (∘C) 119879maxlowastlowast (∘C)
100 200 300 400 500 600 700 800 (∘C)BEF ligand 0153 0365 4414 6236 6718 7140 8224 9442 310 825BEFminusCu 0194 1432 3180 4301 4996 5549 6686 8122 500 860BEFminusNi 0893 1660 3735 4935 6460 8767 mdash mdash 405 650BEFminusZn 1464 2262 3833 4616 5726 6492 7614 9129 425 830lowastTemperature of 50 weight loss lowastlowastmaximum decomposition temperature
80
60
40
20
0
0
(a)(b)
(c)(d)
200 400 600 800 1000
100
Wei
ght (
)
Temperature (∘C)
Figure 9 TGA of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d)BEFndashZn
above 150∘C may be due to its coordination to the metalatom present in chelates In the present study in the case ofBEFndashCu2+ Ni2+ and Zn2+ complexes the removal of waterfrom the complex was completed within 150∘C These watermolecules are probably crystal or lattice water moleculesTheremoval of water molecules observed in the range of 150ndash200∘C (found 559ndash608 calc 545ndash551) of all the metalchelates is due to the elimination of two coordinated watermolecules These observations further confirm the distortedoctahedral geometry of BEF metal complexes
The thermogravimetric curves of all the BEF metalchelates showed two degradation steps after loss of watermolecules whichmay indicate that the first step (200ndash600∘C)is faster than the second step (600ndash860∘C) This may bedue to the fact that the noncoordinated part of the liganddecomposes firstwhile the coordinated part decomposes laterand finally it may form the representative metal oxides Theweight of the residues confirms fairly well that ofmetal oxides(found 1247ndash1362 calc 1143ndash1232)
The thermal degradation data of the BEF terpolymerand its metal complexes reveal that the polymeric complexesshow better stability than the BEF terpolymer due to thecoordination of metal ions The order of thermal stability ofthe BEF polymer and its complexes is BEFndashCu2+ gt BEFndashZn2+ gt BEF ligand gt BEFndashNi2+ The greater stability of themetal complexes may be due to the coordination and theenhanced cross linking nature with crowd effect of the metal
complexes [31] In the case of Ni2+ complex the degradationoccurred exceptionally at low temperature compared to theirligand which may be due to the oxidation of polymer by thecatalytic action of the metal ion [32]
383 Thermal Kinetics
(1) Sharp-Wentworth and Freeman-Carroll Method Ther-mal kinetic analysis was performed using Sharp-Wentworthmethod and Freeman-Carroll methods The activationenergy (119864
119886) and order of reaction (119899) plots for BEF terpoly-
mer ligand and its metal complexes by Sharp-Wentworthand Freeman-Carroll methods are shown in Figures 10 11and 12 The expressions used to calculate the kinetic andthermodynamic parameters are presented as follows
(i) Entropy change (Δ119878)
Intercept = log 119870119877
ℎΦ119864119886
+Δ119878
2303119877 (2)
where 119870 = 13806 times 10minus16 ergdegmole 119877 =
1987 caldegmole (8314 JKMol) ℎ = 6625 times
10minus27 erg sec Φ = 0166 Δ119878 = change in entropyand 119864
119886= activation energy from graph
(ii) Free energy change (Δ119865)
Δ119865 = Δ119867 minus 119879Δ119878 (3)
where Δ119867 = enthalpy change = activation energy 119879 =temperature in119870 and Δ119878 = result from (2)
(iii) Frequency factor (119885)
11986123
=log119885119864
119886
119877Φ (4)
11986123
= log 3 + log [1 minus 3radic1 minus 120572] minus log119901 (119909) (5)
where 119885 is the frequency factor 119861 is calculatedfrom (5) log119901(119909) is calculated from Doylersquos tablecorresponding to activation energy and 120572 is degreeof transformation (120572 = 119908119882
119888)
(iv) Apparent entropy (119878lowast)
119878lowast= 2303 log 119885ℎ
119877119879lowast (6)
where119885 is calculated from (4) and 119879lowast is half decom-position temperature
Bioinorganic Chemistry and Applications 11
1000T (Kminus1)
Intercept = minus535
minus45
minus50
minus55
minus60
minus65
minus70
minus75
minus80
10 15 20 25 30
Ea = 952
log[
(dC
dT
)(1
minusC
)]
(a)
minus64
minus62
minus60
minus58
minus56
minus54
minus52
1000T (Kminus1)10 15 20 25 30
Intercept = minus527
Ea = 1297
log[
(dC
dT
)(1
minusC
)]
(b)
minus64
minus62
minus50
minus52
minus54
minus56
minus58
minus60
1000T (Kminus1)10 15 20 25 30
Intercept = minus513
Ea = 693
log[
(dC
dT
)(1
minusC
)]
(c)
minus50
minus51
minus52
minus53
minus54
minus55
minus56
minus57
minus58
minus59
1000T (Kminus1)10 15 20 25 30
Intercept = minus538
Ea = 1108
log[
(dC
dT
)(1
minusC
)]
(d)
Figure 10 Sharp-Wentworth plots of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Table 5 Kinetic and thermodynamic parameters data
CompoundActivation energy
(119864119886kJmolminus1) Entropy change
(Δ119878J)Free energy
change (Δ119865kJ)Frequency
factor (119885sminus1)Apparent
entropy (119878lowastJ)Order of
reaction (119899)lowastSW lowastlowastFC
BEF ligand 952 1039 minus15811 5940 1310 minus2295 090BEFminusCu 1297 1367 minus15425 9079 1205 minus2331 104BEFminusNi 693 460 minus16290 7057 1537 minus2294 093BEFminusZn 1108 1213 minus16001 8013 1243 minus2318 102lowastSW Sharp-Wentworth lowastlowastFC Freeman-Carroll
Further from the knowledge of activation energy cal-culated by Freeman-Carroll method it is possible to eval-uate the values of various thermodynamic parameters Theorder of reaction (119899) and activation energy (119864
119886) and the
thermodynamic parameters such as frequency factor (119885)entropy change (Δ119878) free energy change (Δ119865) and apparententropy (119878lowast) are presented inTable 5The119864
119886values calculated
by SW and FC methods are in good agreement with eachother The order of activation energies for BEF ligand andits Cu2+ Ni2+ and Zn2+ complexes is parallel to the orderof their thermal stability [32] The values of thermodynamic
parameters were comparable indicating a common modeof decomposition reaction The abnormal low values offrequency factor (119885) indicate that the decomposition reactionof BEF terpolymer and its metal complexes can be depictedas a slow reaction The order of reactions (119899) of BEF ligandand its metal complexes is found to be 090 104 093 and102 respectively Hence the BEF terpolymer and its mealcomplexes may be following nearly a first order kinetics
(2) Phadnis-Deshpande Method The activation energiescalculated for BEF ligand and its metal complexes using
12 Bioinorganic Chemistry and Applications
minus00012minus00010minus00008minus00006minus00004minus00002minus00000
26242220181614121008060402
log(dWdt)
(1T)
n = 090
logW
r
logWr
(a)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
20
19
18
17
16
15
14
13
12
11
10
log(dWdt)
(1T)
n = 104
logWr
logW
r
(b)
15
16
17
18
19
14
13
12
11
10
09
log(dWdt)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
(1T)
n = 093logW
r
logWr
(c)
15
16
17
18
14
13
12
11
10
log(dWdt)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
(1T)
n = 102
logW
r
logWr
(d)
Figure 11 Freeman-Carroll plots (119899) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Phadnis-Deshpande method are presented in Table 6 Fromthe 119864
119886values it is possible to propose the degradation
reactionmechanism using PDmethod Further the 119864119886values
calculated by PD method are in good agreement with FCand SW methods Based on the closest 119864
119886values calculated
by PD SW and FC methods the Power law mechanismsuits very well for the BEF ligand and BEFndashCu and BEFndashZn metal complexes However BEFndashNi complex follows theBrounshtein-Ginstling 3-dimensional diffusion mechanism
39 Biological Studies
391 Antibacterial Activity To determine the antibacterialactivity of the BEF terpolymer and its Cu2+ Ni2+ andZn2+ complexes the disc diffusion method was used withamoxicillin as the standard antibiotic The prepared com-pounds were tested against Shigella sonnei Escherichia coliKlebsiella species Staphylococcus aureus Bacillus subtilis andSalmonella typhimuriummicroorganisms
Table 7 contains the screening results corresponding tothe polymeric ligand and its metal complexes with fairinhibition of growth against the tested organisms Shigella
sonnei is a nonmotile non-spore-forming and facultativeanaerobic gram-negative bacterium Shigella bacteria multi-ply within colonic epithelial cells and cause mucosal ulcer-ation inflammation bleeding high fever malaise diarrheaand tenesmus The ligand and its metal complexes showeda reasonable activity against the S sonnei species E coliis an aerobic gram-negative and rod shaped bacteriumInfection of E coli can lead to bloody diarrhea and kidneyfailureThe polymeric ligand and its complexes hold amodestactivity against the E coli Klebsiella is a genus of nonmotileand gram-negative bacteria that infects sites such as nasalpassages liver lung urinary tract bloodstream eye boneand joints It causes a wide range of disease states notablypneumonia septicemia soft tissue infections biliary tractinfection infection of the upper and lower respiratory tractand liver abscess The BEF ligand and its metal complexesshowed a reasonable result against the growth of KlebsiellaStaphylococcus aureus a gram-positive and spherical bac-terium leads to life-threatening diseases like pneumoniaosteomyelitis endocarditis and toxic shock syndrome Toxicshock syndrome is characterized by the sudden onset of highfever vomiting diarrhea and muscle aches followed by lowblood pressure (hypotension) which can lead to shock and
Bioinorganic Chemistry and Applications 13
log[g
(120572)T3]
minus95
minus90
minus85
minus80
minus75
10 15 20 25 30
Intercept = minus825
Ea = 1039
1000T (Kminus1)
(a)
log[g
(120572)T3]
minus78
minus80
minus82
minus84
minus86
minus88
minus90
minus92
minus94
minus96
minus76
Intercept = minus805
Ea = 1367
10 15 20 25 30
1000T (Kminus1)
(b)
log[g
(120572)T3]
minus77
minus78
minus79
minus80
minus81
minus82
minus83
minus84
minus85
minus86
minus87
minus88minus89
Intercept = minus849
Ea = 460
10 15 20 25 30
1000T (Kminus1)
(c)
minus78
minus80
minus82
minus84
minus86
minus7610 15 20 25 30
1000T (Kminus1)
log[g
(120572)T3]
Intercept = minus835
Ea = 1213
(d)
Figure 12 Freeman-Carroll plots (119864119886) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Table 6 Activation energies calculated by Phadnis-Deshpande method
Reaction mechanism model Energy of activation (119864119886) (kJmol)
BEF ligand BEFminusCu BEFminusNi BEFminusZnPower law 60932 62642 59691 54312Power law 121864 125284 119382 108625Phase boundary (contracting sphere) 16497 16816 16174 15009Phase boundary (contracting cylinder) 25894 26436 25383 23466Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 12135 13830 11756 07447
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 08090 09220 07837 04964
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 06067 06915 05878 03723
Valensi 2-dimensional diffusion 168354 171926 165034 152695Jander 3-dimensional diffusion 32995 33632 32349 30018Brounshtein-Ginstling 3-dimensional diffusion 56520 55015 55669 57981The values indicated in bold are closest to the 119864119886 value estimated by FC and SWmethods
14 Bioinorganic Chemistry and Applications
Table 7 Antibacterial activity of BEF ligand and its complexes
Compound Inhibition zone (mm)S sonnei E coli Klebsiella sp S aureus B subtilis S typhi
BEF ligand 15 13 13 14 15 12BEFndashCu 21 17 17 18 18 18BEFndashNi 18 15 18 17 20 15BEFndashZn 16 15 15 16 17 15Standard 26 28 26 25 27 28Control mdash mdash mdash mdash mdash mdashStandard amoxicillin control DMSO
Table 8 Antifungal activity of BEF ligand and its complexes
Compound Inhibition zone (mm)Aspergillus flavus Aspergillus niger Penicillium species Candida albicans Cryptococcus neoformans Mucorspecies
BEF ligand 14 12 12 13 11 12BEFndashCu 20 18 19 18 15 19BEFndashNi 17 14 17 15 13 13BEFndashZn 15 15 18 17 14 16Standard 20 21 19 21 18 22Control mdash mdash mdash mdash mdash mdashStandard fluconazole control DMSO
death There may be a rash resembling sunburn with peelingof skin The ligand and its complexes showed a humbleactivity against the growth of S aureus Bacillus subtilis arerod-shaped and nonpathogenic gram-positive bacteria TheBEF ligand and complexes showed superb activity againstthe growth of this bacterium Salmonella typhimurium is apathogenic gram-negative bacteria predominately found inthe intestinal lumen When the bacterial cells enter epithelialcells lining the intestine they cause host cell ruffling whichtemporarily damages the microvilli on the surface of the cellThis causes a rush of white blood cells into the mucosa andleads to diarrheaThe ligand and its metal complexes showeda moderate activity against the growth of the typhi species
A comparative account on the effect of antibacterialactivity against the chosen microbes indicates that the ligandand its three metal chelates show reasonable activity againstShigella sonnei (15 21 18 and 16mm) and Bacillus subtilis (1518 20 and 17mm) while the growth of other organisms ismoderately inhibited by the BEF ligand and its Cu2+ Ni2+and Zn2+ chelates The highest antibacterial action (21mm)has been observed for BEFndashCu2+ complex against Shigellasonnei
392 Antifungal Activity The antifungal activity of the BEFligand and its metal complexes has also given interestingresults and the growth inhibitions against the chosen fungalstrains are tabulated in Table 8 All the complexes and theirligand have an excellent activity against Aspergillus flavusa mold type fungal strain which may invade arteries of thelung or brain to cause infections and also produce a toxinAspergillus niger is one of the most common causes for
otomycosis The chelates and the ligand are found to havea reasonable activity for A niger Penicillium species causesinfection in humans and the resulting disease is known gener-ically as penicilliosis The ligand and the metal complexeshave wonderful activity against this species Further BEFndashCucomplex has a superior activity compared to the rest of othercomplexes Candida albicans is a diploid fungus and a causalagent of opportunistic oral and genital infections in humansand also emerged as an important cause of morbidity andmortality in immunocompromised patients The BEF ligandand its chelates possess a modest activity against C albicansover and above the standard Cryptococcus neoformans is anencapsulated yeast-like fungus that can live in both plantsand animals and cause lung infection The terpolymer ligandand its chelates have a fair activity against this fungal strainThe chelate compounds and the ligand havemoderate activityagainst Mucor species a filamentous fungus which causesseptic arthritis renal infections and pulmonary infections
From the antimicrobial results themetal complexes showhigher activity than their ligand which may be stronglydependent on the central metal ions and coordination num-bers metal chelates The higher activity due to the metal ionsshared with the donor atoms (N and S) of the thiazole ring ispresent in the ligand and the 120587-electron delocalization overthe chelate ring This effect increases the lipophilic characterof the metal ion which favors the permeation through thelipoid layers of the bacterial and fungal membranes [33 34]It is perceived that the factors such as solubility conductivitydipole moment and cell permeability may also contributeto the increased activity of the complexes [35 36] Fromthe results of the studies at 500 ppm concentration thecompounds establish better antimicrobial activity Hence it
Bioinorganic Chemistry and Applications 15
is an interesting result that a very low concentration of thecompound namely 500 ppm is enough to bring out aneffective inhibition against the chosen microbes
4 Conclusion
The synthesized 2-amino-6-nitro-benzothiazole-ethylene-diamine-formaldehyde terpolymer has acted as a ligandsuccessfully to form metal complexes The synthesized com-pounds were well characterized by various spectral andphysical analyses The morphological features suggest thatthe complexes are slightly more crystalline in nature thantheir parent ligandThe antibacterial and antifungal activitiesreveal that the terpolymer and its metal complexes can beactive against the selected bacterial and fungal strains Nearlyall of the compoundsmay suit well for drug delivery field afterchecking for their toxicology behaviour in thorough mannerThermal studies are also helpful to realize the standing capac-ity of the compounds which survive as antimicrobial coatingmaterials in various environmental conditions Because ofthe proven high stability nature and microbial preventioncapacity the BEF terpolymer and its Cu2+ Ni2+ and Zn2+complexes hold inadequate applications in biological fieldThe thermal stability of the terpolymer and its metal com-plexes was found greater From the thermodynamic andkinetic studies the abnormal low values of frequency factor(119885) indicate that the thermal decomposition reaction of BEFterpolymer and its metal complexes can be depicted as a slowreaction The BEF terpolymer and its metal complexes maybe following nearly a first order kinetics
Conflict of Interests
The authors certify that there is no conflict of interests withany financial organization regarding thematerial discussed inthe paper
Acknowledgments
The authors thank the Management and Principal ofOxford Engineering College Tiruchirappalli CoimbatoreInstitute of Technology Coimbatore Jamal Mohamed Col-lege (Autonomous) Tiruchirappalli Tamil Nadu and DrD Jeyakumar Scientist Central Electrochemical ResearchInstitute (CECRI-CSIR) Karaikudi Tamil Nadu for theirsupport and encouragement
References
[1] C U Pittman K S Ramachandran Jr and K R LowyerldquoSynthesis of fungicidal monomers polymers and latticesrdquoJournal of Coating Technology vol 54 pp 27ndash40 1982
[2] M N Patel J R Patel and D H Sutaria ldquoNovel co-ordinationpolychelatesrdquo Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry vol 24 no 8 pp 1297ndash1309 1994
[3] V V Ukey and H D Juneja ldquoSynthetic and spectroscopicstudies of chelate polymers involving azelaoyl bis-N-phenylhydroxamic acid with transition metal ionsrdquo Journal of AppliedPolymer Science vol 99 no 1 pp 273ndash278 2006
[4] S K-H Thiele and D R Wilson ldquoAlternate transition metalcomplex based diene polymerizationrdquo Polymer Reviews vol 43no 4 pp 581ndash628 2003
[5] N Nishat S Ahmad and T Ahamad ldquoSynthesis and character-ization of antibacterial polychelates of urea-formaldehyde resinwith Cr(III) Mn(II) Fe(III) Co(II) Ni(II) Cu(II) and Zn(II)metal ionsrdquo Journal of Applied Polymer Science vol 100 no 2pp 928ndash936 2006
[6] E Brzezinska G Koska and K Walczynski ldquoApplicationof thin-layer chromatographic data in quantitative structure-activity relationship assay of thiazole and benzothiazole deriva-tives with Hmdashantihistamine activityrdquo Journal of Chromatogra-phy A vol 1007 pp 145ndash155 2003
[7] M A R Ahamed and A R Burkanudeen ldquoMetal complexesof a novel terpolymer ligand synthesis spectral morphologythermal degradation kinetics and antimicrobial screeningrdquoJournal of Inorganic andOrganometallic Polymers andMaterialsvol 22 no 5 pp 1046ndash1061 2012
[8] B S Holla K V Malini V S Rao B K Sarojini and N SKumari ldquoSynthesis of some new 24-disubstituted thiazoles aspossible antibacterial and anti-inflammatory agentsrdquo EuropeanJournal of Medicinal Chemistry vol 38 no 3 pp 313ndash318 2003
[9] O I El-Sabbagh M M Baraka S M Ibrahim et al ldquoSynthesisand antiviral activity of new pyrazole and thiazole derivativesrdquoEuropean Journal of Medicinal Chemistry vol 44 no 9 pp3746ndash3753 2009
[10] A Andreani M Granaiola A Leoni A Locatelli R Morigiand M Rambaldi ldquoSynthesis and antitubercular activity ofimidazo[21-b]thiazolesrdquo European Journal of Medicinal Chem-istry vol 36 no 9 pp 743ndash746 2001
[11] E Yousif Y Farina K Kasar A Graisa and K Ayid ldquoCom-plexes of 2-thioacetic acid benzothiazole with somemetal ionsrdquoAmerican Journal of Applied Sciences vol 6 no 4 pp 582ndash5852009
[12] B P Mallikarjuna B S Sastry G V Suresh Kumar Y Rajen-draprasad S M Chandrashekar and K Sathisha ldquoSynthesis ofnew 4-isopropylthiazole hydrazide analogs and some derivedclubbed triazole oxadiazole ring systemsmdasha novel class ofpotential antibacterial antifungal and antitubercular agentsrdquoEuropean Journal of Medicinal Chemistry vol 44 pp 4739ndash4746 2009
[13] T Ahamad V Kumar and N Nishat ldquoNew class of anti-microbial agents synthesis characterization and anti-microbial activities of metal chelated polyureardquo Journal ofBiomedical Materials Research A vol 88 no 2 pp 288ndash2942009
[14] M V Patel J N Patel M B Dolia and R M Patel ldquoPolyether-ketones synthesis characterization and antimicrobial activityrdquoInternational Journal of Polymeric Materials and PolymericBiomaterials vol 54 no 11 pp 1059ndash1071 2005
[15] K R Alagawadi and S G Alegaon ldquoSynthesis characteriza-tion and antimicrobial activity evaluation of new 24-Thiazoli-dinediones bearing imidazo[21-b][134]thiadiazole moietyrdquoArabian Journal of Chemistry vol 4 no 4 pp 465ndash472 2011
[16] M Ashok B S Holla and N S Kumari ldquoConvenientone pot synthesis of some novel derivatives of thiazolo[23-b]dihydropyrimidinone possessing 4-methylthiophenyl moietyand evaluation of their antibacterial and antifungal activitiesrdquoEuropean Journal ofMedicinal Chemistry vol 42 no 3 pp 380ndash385 2007
16 Bioinorganic Chemistry and Applications
[17] T Ahamad V Kumar S Parveen and N Nishat ldquoIn vitroantibacterial and antifungal assay of poly-(ethylene oxamide-NN1015840-diacetate) and its polymer-metal complexesrdquo AppliedOrganometallic Chemistry vol 21 no 12 pp 1013ndash1021 2007
[18] R S Azarudeen M A R Ahamed and A R BurkanudeenldquoBiological and thermal investigations of polychelates derivedfrom a novel terpolymer ligandrdquo Journal of Polymer Researchvol 18 no 6 pp 1331ndash1341 2011
[19] R S Azarudeen and A R Burkanudeen ldquoSynthesis spectralmorphology thermal degradation kinetics and antibacterialstudies of terpolymermetal complexesrdquo Journal of Inorganic andOrganometallic Polymers and Materials vol 22 no 4 pp 791ndash806 2012
[20] R S Azarudeen and A R Burkanudeen ldquoStudies of newoligomer-metal complexes and their antibacterial activitiesrdquoPolymer International vol 62 no 3 pp 362ndash374 2013
[21] G S Devi A K Muthu D S Kumar S Rekha R Indhumathiand R Nandhini ldquoStudies on the antibacterial and antifungalactivities of the ethanolic extracts of Luffa cylindrica (Linn)fruitrdquo International Journal of Drug Development and Researchvol 1 pp 105ndash109 2013
[22] R M Silverstein and G C Bassler Spectrometric IdentificationofOrganic Compounds JohnWileyamp SonsNewYorkNYUSA2nd edition 1967
[23] Y-G Zhao H-Y Shen S-D Pan and M-Q Hu ldquoSyn-thesis characterization and properties of ethylenediamine-functionalized Fe
3O4magnetic polymers for removal of Cr(VI)
in wastewaterrdquo Journal of Hazardous Materials vol 182 no 1-3pp 295ndash302 2010
[24] Y R Sharma Elementary Organic Absorption Spectroscopy SChand amp Co Ltd New Delhi India 1980
[25] D Kivelson and R Neiman ldquoESR line shapes in glasses ofcopper complexesrdquoThe Journal of Chemical Physics vol 35 no1 pp 149ndash155 1961
[26] E Pretsch P Buhlmann and C Afflolter Structure Determi-nation of Organic Compounds Springer New York NY USA2000
[27] J L White Modern Magnetic Resonance Kluwer AcademicPress London UK 2006
[28] M M Patel M A Kapadia and J D Joshi ldquoThermal andcatalytic aspects of Ln(III) polymer-metal complexesrdquo PolymerInternational vol 58 no 7 pp 728ndash737 2009
[29] S Nanjundan C S J Selvamalar and R Jayakumar ldquoSynthesisand characterization of poly(3-acetyl-4-hydroxyphenyl acry-late) and its Cu(II) and Ni(II) complexesrdquo European PolymerJournal vol 40 no 10 pp 2313ndash2321 2004
[30] A V Nikolaev V A Logvinenco and L I Myachina ThermalAnalysis Academic Press New York NY USA 1969
[31] A Z El-Sonbati and M A Hefni ldquoPolymer complexes PartXXVImdashNovel mixed ligand poly-(5-vinyl salicylidene)-12-diaminobenzene complexesrdquo Polymer Degradation and Stabil-ity vol 43 no 1 pp 33ndash42 1994
[32] A S Aswar and N S Bhave ldquoThermal degradation studies ofsome new coordination polymersrdquo Polymer Degradation andStability vol 31 no 1 pp 115ndash124 1991
[33] T Ahamad V Kumar and N Nishat ldquoSynthesis characteri-zation and antimicrobial activity of transition metal chelatedthiourea-formaldehyde resinrdquo Polymer International vol 55no 12 pp 1398ndash1406 2006
[34] M M Patel M A Kapadia G P Patel and J D Joshi ldquoSynthe-sis characterization ion-exchange and antimicrobial study of
poly[(2-hydroxy-4-methoxybenzophenone) propylene] resinand its polychelates with lanthanides (III)rdquo Journal of AppliedPolymer Science vol 106 no 2 pp 1307ndash1317 2007
[35] M A Neelakantan S S Marriappan J Dharmaraja T Jeyaku-mar and K Muthukumaran ldquoSpectral XRD SEM and bio-logical activities of transition metal complexes of polydentateligands containing thiazole moietyrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 71 no 2 pp 628ndash635 2008
[36] G B Bagihalli S A Patil and P S Badami ldquoSynthesisphysicochemical investigation and biological studies of zinc(II)complexes with 124-triazole schiff basesrdquo Journal of the IranianChemical Society vol 6 no 2 pp 259ndash270 2009
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Inorganic ChemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Carbohydrate Chemistry
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
Physical Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom
Analytical Methods in Chemistry
Journal of
Volume 2014
Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
SpectroscopyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Medicinal ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chromatography Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Applied ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Theoretical ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Spectroscopy
Analytical ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Quantum Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Organic Chemistry International
ElectrochemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CatalystsJournal of
Bioinorganic Chemistry and Applications 11
1000T (Kminus1)
Intercept = minus535
minus45
minus50
minus55
minus60
minus65
minus70
minus75
minus80
10 15 20 25 30
Ea = 952
log[
(dC
dT
)(1
minusC
)]
(a)
minus64
minus62
minus60
minus58
minus56
minus54
minus52
1000T (Kminus1)10 15 20 25 30
Intercept = minus527
Ea = 1297
log[
(dC
dT
)(1
minusC
)]
(b)
minus64
minus62
minus50
minus52
minus54
minus56
minus58
minus60
1000T (Kminus1)10 15 20 25 30
Intercept = minus513
Ea = 693
log[
(dC
dT
)(1
minusC
)]
(c)
minus50
minus51
minus52
minus53
minus54
minus55
minus56
minus57
minus58
minus59
1000T (Kminus1)10 15 20 25 30
Intercept = minus538
Ea = 1108
log[
(dC
dT
)(1
minusC
)]
(d)
Figure 10 Sharp-Wentworth plots of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Table 5 Kinetic and thermodynamic parameters data
CompoundActivation energy
(119864119886kJmolminus1) Entropy change
(Δ119878J)Free energy
change (Δ119865kJ)Frequency
factor (119885sminus1)Apparent
entropy (119878lowastJ)Order of
reaction (119899)lowastSW lowastlowastFC
BEF ligand 952 1039 minus15811 5940 1310 minus2295 090BEFminusCu 1297 1367 minus15425 9079 1205 minus2331 104BEFminusNi 693 460 minus16290 7057 1537 minus2294 093BEFminusZn 1108 1213 minus16001 8013 1243 minus2318 102lowastSW Sharp-Wentworth lowastlowastFC Freeman-Carroll
Further from the knowledge of activation energy cal-culated by Freeman-Carroll method it is possible to eval-uate the values of various thermodynamic parameters Theorder of reaction (119899) and activation energy (119864
119886) and the
thermodynamic parameters such as frequency factor (119885)entropy change (Δ119878) free energy change (Δ119865) and apparententropy (119878lowast) are presented inTable 5The119864
119886values calculated
by SW and FC methods are in good agreement with eachother The order of activation energies for BEF ligand andits Cu2+ Ni2+ and Zn2+ complexes is parallel to the orderof their thermal stability [32] The values of thermodynamic
parameters were comparable indicating a common modeof decomposition reaction The abnormal low values offrequency factor (119885) indicate that the decomposition reactionof BEF terpolymer and its metal complexes can be depictedas a slow reaction The order of reactions (119899) of BEF ligandand its metal complexes is found to be 090 104 093 and102 respectively Hence the BEF terpolymer and its mealcomplexes may be following nearly a first order kinetics
(2) Phadnis-Deshpande Method The activation energiescalculated for BEF ligand and its metal complexes using
12 Bioinorganic Chemistry and Applications
minus00012minus00010minus00008minus00006minus00004minus00002minus00000
26242220181614121008060402
log(dWdt)
(1T)
n = 090
logW
r
logWr
(a)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
20
19
18
17
16
15
14
13
12
11
10
log(dWdt)
(1T)
n = 104
logWr
logW
r
(b)
15
16
17
18
19
14
13
12
11
10
09
log(dWdt)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
(1T)
n = 093logW
r
logWr
(c)
15
16
17
18
14
13
12
11
10
log(dWdt)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
(1T)
n = 102
logW
r
logWr
(d)
Figure 11 Freeman-Carroll plots (119899) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Phadnis-Deshpande method are presented in Table 6 Fromthe 119864
119886values it is possible to propose the degradation
reactionmechanism using PDmethod Further the 119864119886values
calculated by PD method are in good agreement with FCand SW methods Based on the closest 119864
119886values calculated
by PD SW and FC methods the Power law mechanismsuits very well for the BEF ligand and BEFndashCu and BEFndashZn metal complexes However BEFndashNi complex follows theBrounshtein-Ginstling 3-dimensional diffusion mechanism
39 Biological Studies
391 Antibacterial Activity To determine the antibacterialactivity of the BEF terpolymer and its Cu2+ Ni2+ andZn2+ complexes the disc diffusion method was used withamoxicillin as the standard antibiotic The prepared com-pounds were tested against Shigella sonnei Escherichia coliKlebsiella species Staphylococcus aureus Bacillus subtilis andSalmonella typhimuriummicroorganisms
Table 7 contains the screening results corresponding tothe polymeric ligand and its metal complexes with fairinhibition of growth against the tested organisms Shigella
sonnei is a nonmotile non-spore-forming and facultativeanaerobic gram-negative bacterium Shigella bacteria multi-ply within colonic epithelial cells and cause mucosal ulcer-ation inflammation bleeding high fever malaise diarrheaand tenesmus The ligand and its metal complexes showeda reasonable activity against the S sonnei species E coliis an aerobic gram-negative and rod shaped bacteriumInfection of E coli can lead to bloody diarrhea and kidneyfailureThe polymeric ligand and its complexes hold amodestactivity against the E coli Klebsiella is a genus of nonmotileand gram-negative bacteria that infects sites such as nasalpassages liver lung urinary tract bloodstream eye boneand joints It causes a wide range of disease states notablypneumonia septicemia soft tissue infections biliary tractinfection infection of the upper and lower respiratory tractand liver abscess The BEF ligand and its metal complexesshowed a reasonable result against the growth of KlebsiellaStaphylococcus aureus a gram-positive and spherical bac-terium leads to life-threatening diseases like pneumoniaosteomyelitis endocarditis and toxic shock syndrome Toxicshock syndrome is characterized by the sudden onset of highfever vomiting diarrhea and muscle aches followed by lowblood pressure (hypotension) which can lead to shock and
Bioinorganic Chemistry and Applications 13
log[g
(120572)T3]
minus95
minus90
minus85
minus80
minus75
10 15 20 25 30
Intercept = minus825
Ea = 1039
1000T (Kminus1)
(a)
log[g
(120572)T3]
minus78
minus80
minus82
minus84
minus86
minus88
minus90
minus92
minus94
minus96
minus76
Intercept = minus805
Ea = 1367
10 15 20 25 30
1000T (Kminus1)
(b)
log[g
(120572)T3]
minus77
minus78
minus79
minus80
minus81
minus82
minus83
minus84
minus85
minus86
minus87
minus88minus89
Intercept = minus849
Ea = 460
10 15 20 25 30
1000T (Kminus1)
(c)
minus78
minus80
minus82
minus84
minus86
minus7610 15 20 25 30
1000T (Kminus1)
log[g
(120572)T3]
Intercept = minus835
Ea = 1213
(d)
Figure 12 Freeman-Carroll plots (119864119886) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Table 6 Activation energies calculated by Phadnis-Deshpande method
Reaction mechanism model Energy of activation (119864119886) (kJmol)
BEF ligand BEFminusCu BEFminusNi BEFminusZnPower law 60932 62642 59691 54312Power law 121864 125284 119382 108625Phase boundary (contracting sphere) 16497 16816 16174 15009Phase boundary (contracting cylinder) 25894 26436 25383 23466Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 12135 13830 11756 07447
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 08090 09220 07837 04964
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 06067 06915 05878 03723
Valensi 2-dimensional diffusion 168354 171926 165034 152695Jander 3-dimensional diffusion 32995 33632 32349 30018Brounshtein-Ginstling 3-dimensional diffusion 56520 55015 55669 57981The values indicated in bold are closest to the 119864119886 value estimated by FC and SWmethods
14 Bioinorganic Chemistry and Applications
Table 7 Antibacterial activity of BEF ligand and its complexes
Compound Inhibition zone (mm)S sonnei E coli Klebsiella sp S aureus B subtilis S typhi
BEF ligand 15 13 13 14 15 12BEFndashCu 21 17 17 18 18 18BEFndashNi 18 15 18 17 20 15BEFndashZn 16 15 15 16 17 15Standard 26 28 26 25 27 28Control mdash mdash mdash mdash mdash mdashStandard amoxicillin control DMSO
Table 8 Antifungal activity of BEF ligand and its complexes
Compound Inhibition zone (mm)Aspergillus flavus Aspergillus niger Penicillium species Candida albicans Cryptococcus neoformans Mucorspecies
BEF ligand 14 12 12 13 11 12BEFndashCu 20 18 19 18 15 19BEFndashNi 17 14 17 15 13 13BEFndashZn 15 15 18 17 14 16Standard 20 21 19 21 18 22Control mdash mdash mdash mdash mdash mdashStandard fluconazole control DMSO
death There may be a rash resembling sunburn with peelingof skin The ligand and its complexes showed a humbleactivity against the growth of S aureus Bacillus subtilis arerod-shaped and nonpathogenic gram-positive bacteria TheBEF ligand and complexes showed superb activity againstthe growth of this bacterium Salmonella typhimurium is apathogenic gram-negative bacteria predominately found inthe intestinal lumen When the bacterial cells enter epithelialcells lining the intestine they cause host cell ruffling whichtemporarily damages the microvilli on the surface of the cellThis causes a rush of white blood cells into the mucosa andleads to diarrheaThe ligand and its metal complexes showeda moderate activity against the growth of the typhi species
A comparative account on the effect of antibacterialactivity against the chosen microbes indicates that the ligandand its three metal chelates show reasonable activity againstShigella sonnei (15 21 18 and 16mm) and Bacillus subtilis (1518 20 and 17mm) while the growth of other organisms ismoderately inhibited by the BEF ligand and its Cu2+ Ni2+and Zn2+ chelates The highest antibacterial action (21mm)has been observed for BEFndashCu2+ complex against Shigellasonnei
392 Antifungal Activity The antifungal activity of the BEFligand and its metal complexes has also given interestingresults and the growth inhibitions against the chosen fungalstrains are tabulated in Table 8 All the complexes and theirligand have an excellent activity against Aspergillus flavusa mold type fungal strain which may invade arteries of thelung or brain to cause infections and also produce a toxinAspergillus niger is one of the most common causes for
otomycosis The chelates and the ligand are found to havea reasonable activity for A niger Penicillium species causesinfection in humans and the resulting disease is known gener-ically as penicilliosis The ligand and the metal complexeshave wonderful activity against this species Further BEFndashCucomplex has a superior activity compared to the rest of othercomplexes Candida albicans is a diploid fungus and a causalagent of opportunistic oral and genital infections in humansand also emerged as an important cause of morbidity andmortality in immunocompromised patients The BEF ligandand its chelates possess a modest activity against C albicansover and above the standard Cryptococcus neoformans is anencapsulated yeast-like fungus that can live in both plantsand animals and cause lung infection The terpolymer ligandand its chelates have a fair activity against this fungal strainThe chelate compounds and the ligand havemoderate activityagainst Mucor species a filamentous fungus which causesseptic arthritis renal infections and pulmonary infections
From the antimicrobial results themetal complexes showhigher activity than their ligand which may be stronglydependent on the central metal ions and coordination num-bers metal chelates The higher activity due to the metal ionsshared with the donor atoms (N and S) of the thiazole ring ispresent in the ligand and the 120587-electron delocalization overthe chelate ring This effect increases the lipophilic characterof the metal ion which favors the permeation through thelipoid layers of the bacterial and fungal membranes [33 34]It is perceived that the factors such as solubility conductivitydipole moment and cell permeability may also contributeto the increased activity of the complexes [35 36] Fromthe results of the studies at 500 ppm concentration thecompounds establish better antimicrobial activity Hence it
Bioinorganic Chemistry and Applications 15
is an interesting result that a very low concentration of thecompound namely 500 ppm is enough to bring out aneffective inhibition against the chosen microbes
4 Conclusion
The synthesized 2-amino-6-nitro-benzothiazole-ethylene-diamine-formaldehyde terpolymer has acted as a ligandsuccessfully to form metal complexes The synthesized com-pounds were well characterized by various spectral andphysical analyses The morphological features suggest thatthe complexes are slightly more crystalline in nature thantheir parent ligandThe antibacterial and antifungal activitiesreveal that the terpolymer and its metal complexes can beactive against the selected bacterial and fungal strains Nearlyall of the compoundsmay suit well for drug delivery field afterchecking for their toxicology behaviour in thorough mannerThermal studies are also helpful to realize the standing capac-ity of the compounds which survive as antimicrobial coatingmaterials in various environmental conditions Because ofthe proven high stability nature and microbial preventioncapacity the BEF terpolymer and its Cu2+ Ni2+ and Zn2+complexes hold inadequate applications in biological fieldThe thermal stability of the terpolymer and its metal com-plexes was found greater From the thermodynamic andkinetic studies the abnormal low values of frequency factor(119885) indicate that the thermal decomposition reaction of BEFterpolymer and its metal complexes can be depicted as a slowreaction The BEF terpolymer and its metal complexes maybe following nearly a first order kinetics
Conflict of Interests
The authors certify that there is no conflict of interests withany financial organization regarding thematerial discussed inthe paper
Acknowledgments
The authors thank the Management and Principal ofOxford Engineering College Tiruchirappalli CoimbatoreInstitute of Technology Coimbatore Jamal Mohamed Col-lege (Autonomous) Tiruchirappalli Tamil Nadu and DrD Jeyakumar Scientist Central Electrochemical ResearchInstitute (CECRI-CSIR) Karaikudi Tamil Nadu for theirsupport and encouragement
References
[1] C U Pittman K S Ramachandran Jr and K R LowyerldquoSynthesis of fungicidal monomers polymers and latticesrdquoJournal of Coating Technology vol 54 pp 27ndash40 1982
[2] M N Patel J R Patel and D H Sutaria ldquoNovel co-ordinationpolychelatesrdquo Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry vol 24 no 8 pp 1297ndash1309 1994
[3] V V Ukey and H D Juneja ldquoSynthetic and spectroscopicstudies of chelate polymers involving azelaoyl bis-N-phenylhydroxamic acid with transition metal ionsrdquo Journal of AppliedPolymer Science vol 99 no 1 pp 273ndash278 2006
[4] S K-H Thiele and D R Wilson ldquoAlternate transition metalcomplex based diene polymerizationrdquo Polymer Reviews vol 43no 4 pp 581ndash628 2003
[5] N Nishat S Ahmad and T Ahamad ldquoSynthesis and character-ization of antibacterial polychelates of urea-formaldehyde resinwith Cr(III) Mn(II) Fe(III) Co(II) Ni(II) Cu(II) and Zn(II)metal ionsrdquo Journal of Applied Polymer Science vol 100 no 2pp 928ndash936 2006
[6] E Brzezinska G Koska and K Walczynski ldquoApplicationof thin-layer chromatographic data in quantitative structure-activity relationship assay of thiazole and benzothiazole deriva-tives with Hmdashantihistamine activityrdquo Journal of Chromatogra-phy A vol 1007 pp 145ndash155 2003
[7] M A R Ahamed and A R Burkanudeen ldquoMetal complexesof a novel terpolymer ligand synthesis spectral morphologythermal degradation kinetics and antimicrobial screeningrdquoJournal of Inorganic andOrganometallic Polymers andMaterialsvol 22 no 5 pp 1046ndash1061 2012
[8] B S Holla K V Malini V S Rao B K Sarojini and N SKumari ldquoSynthesis of some new 24-disubstituted thiazoles aspossible antibacterial and anti-inflammatory agentsrdquo EuropeanJournal of Medicinal Chemistry vol 38 no 3 pp 313ndash318 2003
[9] O I El-Sabbagh M M Baraka S M Ibrahim et al ldquoSynthesisand antiviral activity of new pyrazole and thiazole derivativesrdquoEuropean Journal of Medicinal Chemistry vol 44 no 9 pp3746ndash3753 2009
[10] A Andreani M Granaiola A Leoni A Locatelli R Morigiand M Rambaldi ldquoSynthesis and antitubercular activity ofimidazo[21-b]thiazolesrdquo European Journal of Medicinal Chem-istry vol 36 no 9 pp 743ndash746 2001
[11] E Yousif Y Farina K Kasar A Graisa and K Ayid ldquoCom-plexes of 2-thioacetic acid benzothiazole with somemetal ionsrdquoAmerican Journal of Applied Sciences vol 6 no 4 pp 582ndash5852009
[12] B P Mallikarjuna B S Sastry G V Suresh Kumar Y Rajen-draprasad S M Chandrashekar and K Sathisha ldquoSynthesis ofnew 4-isopropylthiazole hydrazide analogs and some derivedclubbed triazole oxadiazole ring systemsmdasha novel class ofpotential antibacterial antifungal and antitubercular agentsrdquoEuropean Journal of Medicinal Chemistry vol 44 pp 4739ndash4746 2009
[13] T Ahamad V Kumar and N Nishat ldquoNew class of anti-microbial agents synthesis characterization and anti-microbial activities of metal chelated polyureardquo Journal ofBiomedical Materials Research A vol 88 no 2 pp 288ndash2942009
[14] M V Patel J N Patel M B Dolia and R M Patel ldquoPolyether-ketones synthesis characterization and antimicrobial activityrdquoInternational Journal of Polymeric Materials and PolymericBiomaterials vol 54 no 11 pp 1059ndash1071 2005
[15] K R Alagawadi and S G Alegaon ldquoSynthesis characteriza-tion and antimicrobial activity evaluation of new 24-Thiazoli-dinediones bearing imidazo[21-b][134]thiadiazole moietyrdquoArabian Journal of Chemistry vol 4 no 4 pp 465ndash472 2011
[16] M Ashok B S Holla and N S Kumari ldquoConvenientone pot synthesis of some novel derivatives of thiazolo[23-b]dihydropyrimidinone possessing 4-methylthiophenyl moietyand evaluation of their antibacterial and antifungal activitiesrdquoEuropean Journal ofMedicinal Chemistry vol 42 no 3 pp 380ndash385 2007
16 Bioinorganic Chemistry and Applications
[17] T Ahamad V Kumar S Parveen and N Nishat ldquoIn vitroantibacterial and antifungal assay of poly-(ethylene oxamide-NN1015840-diacetate) and its polymer-metal complexesrdquo AppliedOrganometallic Chemistry vol 21 no 12 pp 1013ndash1021 2007
[18] R S Azarudeen M A R Ahamed and A R BurkanudeenldquoBiological and thermal investigations of polychelates derivedfrom a novel terpolymer ligandrdquo Journal of Polymer Researchvol 18 no 6 pp 1331ndash1341 2011
[19] R S Azarudeen and A R Burkanudeen ldquoSynthesis spectralmorphology thermal degradation kinetics and antibacterialstudies of terpolymermetal complexesrdquo Journal of Inorganic andOrganometallic Polymers and Materials vol 22 no 4 pp 791ndash806 2012
[20] R S Azarudeen and A R Burkanudeen ldquoStudies of newoligomer-metal complexes and their antibacterial activitiesrdquoPolymer International vol 62 no 3 pp 362ndash374 2013
[21] G S Devi A K Muthu D S Kumar S Rekha R Indhumathiand R Nandhini ldquoStudies on the antibacterial and antifungalactivities of the ethanolic extracts of Luffa cylindrica (Linn)fruitrdquo International Journal of Drug Development and Researchvol 1 pp 105ndash109 2013
[22] R M Silverstein and G C Bassler Spectrometric IdentificationofOrganic Compounds JohnWileyamp SonsNewYorkNYUSA2nd edition 1967
[23] Y-G Zhao H-Y Shen S-D Pan and M-Q Hu ldquoSyn-thesis characterization and properties of ethylenediamine-functionalized Fe
3O4magnetic polymers for removal of Cr(VI)
in wastewaterrdquo Journal of Hazardous Materials vol 182 no 1-3pp 295ndash302 2010
[24] Y R Sharma Elementary Organic Absorption Spectroscopy SChand amp Co Ltd New Delhi India 1980
[25] D Kivelson and R Neiman ldquoESR line shapes in glasses ofcopper complexesrdquoThe Journal of Chemical Physics vol 35 no1 pp 149ndash155 1961
[26] E Pretsch P Buhlmann and C Afflolter Structure Determi-nation of Organic Compounds Springer New York NY USA2000
[27] J L White Modern Magnetic Resonance Kluwer AcademicPress London UK 2006
[28] M M Patel M A Kapadia and J D Joshi ldquoThermal andcatalytic aspects of Ln(III) polymer-metal complexesrdquo PolymerInternational vol 58 no 7 pp 728ndash737 2009
[29] S Nanjundan C S J Selvamalar and R Jayakumar ldquoSynthesisand characterization of poly(3-acetyl-4-hydroxyphenyl acry-late) and its Cu(II) and Ni(II) complexesrdquo European PolymerJournal vol 40 no 10 pp 2313ndash2321 2004
[30] A V Nikolaev V A Logvinenco and L I Myachina ThermalAnalysis Academic Press New York NY USA 1969
[31] A Z El-Sonbati and M A Hefni ldquoPolymer complexes PartXXVImdashNovel mixed ligand poly-(5-vinyl salicylidene)-12-diaminobenzene complexesrdquo Polymer Degradation and Stabil-ity vol 43 no 1 pp 33ndash42 1994
[32] A S Aswar and N S Bhave ldquoThermal degradation studies ofsome new coordination polymersrdquo Polymer Degradation andStability vol 31 no 1 pp 115ndash124 1991
[33] T Ahamad V Kumar and N Nishat ldquoSynthesis characteri-zation and antimicrobial activity of transition metal chelatedthiourea-formaldehyde resinrdquo Polymer International vol 55no 12 pp 1398ndash1406 2006
[34] M M Patel M A Kapadia G P Patel and J D Joshi ldquoSynthe-sis characterization ion-exchange and antimicrobial study of
poly[(2-hydroxy-4-methoxybenzophenone) propylene] resinand its polychelates with lanthanides (III)rdquo Journal of AppliedPolymer Science vol 106 no 2 pp 1307ndash1317 2007
[35] M A Neelakantan S S Marriappan J Dharmaraja T Jeyaku-mar and K Muthukumaran ldquoSpectral XRD SEM and bio-logical activities of transition metal complexes of polydentateligands containing thiazole moietyrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 71 no 2 pp 628ndash635 2008
[36] G B Bagihalli S A Patil and P S Badami ldquoSynthesisphysicochemical investigation and biological studies of zinc(II)complexes with 124-triazole schiff basesrdquo Journal of the IranianChemical Society vol 6 no 2 pp 259ndash270 2009
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Inorganic ChemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Carbohydrate Chemistry
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
Physical Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom
Analytical Methods in Chemistry
Journal of
Volume 2014
Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
SpectroscopyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Medicinal ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chromatography Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Applied ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Theoretical ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Spectroscopy
Analytical ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Quantum Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Organic Chemistry International
ElectrochemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CatalystsJournal of
12 Bioinorganic Chemistry and Applications
minus00012minus00010minus00008minus00006minus00004minus00002minus00000
26242220181614121008060402
log(dWdt)
(1T)
n = 090
logW
r
logWr
(a)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
20
19
18
17
16
15
14
13
12
11
10
log(dWdt)
(1T)
n = 104
logWr
logW
r
(b)
15
16
17
18
19
14
13
12
11
10
09
log(dWdt)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
(1T)
n = 093logW
r
logWr
(c)
15
16
17
18
14
13
12
11
10
log(dWdt)
minus00012 minus00010 minus00008 minus00006 minus00004 minus00002
(1T)
n = 102
logW
r
logWr
(d)
Figure 11 Freeman-Carroll plots (119899) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Phadnis-Deshpande method are presented in Table 6 Fromthe 119864
119886values it is possible to propose the degradation
reactionmechanism using PDmethod Further the 119864119886values
calculated by PD method are in good agreement with FCand SW methods Based on the closest 119864
119886values calculated
by PD SW and FC methods the Power law mechanismsuits very well for the BEF ligand and BEFndashCu and BEFndashZn metal complexes However BEFndashNi complex follows theBrounshtein-Ginstling 3-dimensional diffusion mechanism
39 Biological Studies
391 Antibacterial Activity To determine the antibacterialactivity of the BEF terpolymer and its Cu2+ Ni2+ andZn2+ complexes the disc diffusion method was used withamoxicillin as the standard antibiotic The prepared com-pounds were tested against Shigella sonnei Escherichia coliKlebsiella species Staphylococcus aureus Bacillus subtilis andSalmonella typhimuriummicroorganisms
Table 7 contains the screening results corresponding tothe polymeric ligand and its metal complexes with fairinhibition of growth against the tested organisms Shigella
sonnei is a nonmotile non-spore-forming and facultativeanaerobic gram-negative bacterium Shigella bacteria multi-ply within colonic epithelial cells and cause mucosal ulcer-ation inflammation bleeding high fever malaise diarrheaand tenesmus The ligand and its metal complexes showeda reasonable activity against the S sonnei species E coliis an aerobic gram-negative and rod shaped bacteriumInfection of E coli can lead to bloody diarrhea and kidneyfailureThe polymeric ligand and its complexes hold amodestactivity against the E coli Klebsiella is a genus of nonmotileand gram-negative bacteria that infects sites such as nasalpassages liver lung urinary tract bloodstream eye boneand joints It causes a wide range of disease states notablypneumonia septicemia soft tissue infections biliary tractinfection infection of the upper and lower respiratory tractand liver abscess The BEF ligand and its metal complexesshowed a reasonable result against the growth of KlebsiellaStaphylococcus aureus a gram-positive and spherical bac-terium leads to life-threatening diseases like pneumoniaosteomyelitis endocarditis and toxic shock syndrome Toxicshock syndrome is characterized by the sudden onset of highfever vomiting diarrhea and muscle aches followed by lowblood pressure (hypotension) which can lead to shock and
Bioinorganic Chemistry and Applications 13
log[g
(120572)T3]
minus95
minus90
minus85
minus80
minus75
10 15 20 25 30
Intercept = minus825
Ea = 1039
1000T (Kminus1)
(a)
log[g
(120572)T3]
minus78
minus80
minus82
minus84
minus86
minus88
minus90
minus92
minus94
minus96
minus76
Intercept = minus805
Ea = 1367
10 15 20 25 30
1000T (Kminus1)
(b)
log[g
(120572)T3]
minus77
minus78
minus79
minus80
minus81
minus82
minus83
minus84
minus85
minus86
minus87
minus88minus89
Intercept = minus849
Ea = 460
10 15 20 25 30
1000T (Kminus1)
(c)
minus78
minus80
minus82
minus84
minus86
minus7610 15 20 25 30
1000T (Kminus1)
log[g
(120572)T3]
Intercept = minus835
Ea = 1213
(d)
Figure 12 Freeman-Carroll plots (119864119886) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Table 6 Activation energies calculated by Phadnis-Deshpande method
Reaction mechanism model Energy of activation (119864119886) (kJmol)
BEF ligand BEFminusCu BEFminusNi BEFminusZnPower law 60932 62642 59691 54312Power law 121864 125284 119382 108625Phase boundary (contracting sphere) 16497 16816 16174 15009Phase boundary (contracting cylinder) 25894 26436 25383 23466Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 12135 13830 11756 07447
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 08090 09220 07837 04964
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 06067 06915 05878 03723
Valensi 2-dimensional diffusion 168354 171926 165034 152695Jander 3-dimensional diffusion 32995 33632 32349 30018Brounshtein-Ginstling 3-dimensional diffusion 56520 55015 55669 57981The values indicated in bold are closest to the 119864119886 value estimated by FC and SWmethods
14 Bioinorganic Chemistry and Applications
Table 7 Antibacterial activity of BEF ligand and its complexes
Compound Inhibition zone (mm)S sonnei E coli Klebsiella sp S aureus B subtilis S typhi
BEF ligand 15 13 13 14 15 12BEFndashCu 21 17 17 18 18 18BEFndashNi 18 15 18 17 20 15BEFndashZn 16 15 15 16 17 15Standard 26 28 26 25 27 28Control mdash mdash mdash mdash mdash mdashStandard amoxicillin control DMSO
Table 8 Antifungal activity of BEF ligand and its complexes
Compound Inhibition zone (mm)Aspergillus flavus Aspergillus niger Penicillium species Candida albicans Cryptococcus neoformans Mucorspecies
BEF ligand 14 12 12 13 11 12BEFndashCu 20 18 19 18 15 19BEFndashNi 17 14 17 15 13 13BEFndashZn 15 15 18 17 14 16Standard 20 21 19 21 18 22Control mdash mdash mdash mdash mdash mdashStandard fluconazole control DMSO
death There may be a rash resembling sunburn with peelingof skin The ligand and its complexes showed a humbleactivity against the growth of S aureus Bacillus subtilis arerod-shaped and nonpathogenic gram-positive bacteria TheBEF ligand and complexes showed superb activity againstthe growth of this bacterium Salmonella typhimurium is apathogenic gram-negative bacteria predominately found inthe intestinal lumen When the bacterial cells enter epithelialcells lining the intestine they cause host cell ruffling whichtemporarily damages the microvilli on the surface of the cellThis causes a rush of white blood cells into the mucosa andleads to diarrheaThe ligand and its metal complexes showeda moderate activity against the growth of the typhi species
A comparative account on the effect of antibacterialactivity against the chosen microbes indicates that the ligandand its three metal chelates show reasonable activity againstShigella sonnei (15 21 18 and 16mm) and Bacillus subtilis (1518 20 and 17mm) while the growth of other organisms ismoderately inhibited by the BEF ligand and its Cu2+ Ni2+and Zn2+ chelates The highest antibacterial action (21mm)has been observed for BEFndashCu2+ complex against Shigellasonnei
392 Antifungal Activity The antifungal activity of the BEFligand and its metal complexes has also given interestingresults and the growth inhibitions against the chosen fungalstrains are tabulated in Table 8 All the complexes and theirligand have an excellent activity against Aspergillus flavusa mold type fungal strain which may invade arteries of thelung or brain to cause infections and also produce a toxinAspergillus niger is one of the most common causes for
otomycosis The chelates and the ligand are found to havea reasonable activity for A niger Penicillium species causesinfection in humans and the resulting disease is known gener-ically as penicilliosis The ligand and the metal complexeshave wonderful activity against this species Further BEFndashCucomplex has a superior activity compared to the rest of othercomplexes Candida albicans is a diploid fungus and a causalagent of opportunistic oral and genital infections in humansand also emerged as an important cause of morbidity andmortality in immunocompromised patients The BEF ligandand its chelates possess a modest activity against C albicansover and above the standard Cryptococcus neoformans is anencapsulated yeast-like fungus that can live in both plantsand animals and cause lung infection The terpolymer ligandand its chelates have a fair activity against this fungal strainThe chelate compounds and the ligand havemoderate activityagainst Mucor species a filamentous fungus which causesseptic arthritis renal infections and pulmonary infections
From the antimicrobial results themetal complexes showhigher activity than their ligand which may be stronglydependent on the central metal ions and coordination num-bers metal chelates The higher activity due to the metal ionsshared with the donor atoms (N and S) of the thiazole ring ispresent in the ligand and the 120587-electron delocalization overthe chelate ring This effect increases the lipophilic characterof the metal ion which favors the permeation through thelipoid layers of the bacterial and fungal membranes [33 34]It is perceived that the factors such as solubility conductivitydipole moment and cell permeability may also contributeto the increased activity of the complexes [35 36] Fromthe results of the studies at 500 ppm concentration thecompounds establish better antimicrobial activity Hence it
Bioinorganic Chemistry and Applications 15
is an interesting result that a very low concentration of thecompound namely 500 ppm is enough to bring out aneffective inhibition against the chosen microbes
4 Conclusion
The synthesized 2-amino-6-nitro-benzothiazole-ethylene-diamine-formaldehyde terpolymer has acted as a ligandsuccessfully to form metal complexes The synthesized com-pounds were well characterized by various spectral andphysical analyses The morphological features suggest thatthe complexes are slightly more crystalline in nature thantheir parent ligandThe antibacterial and antifungal activitiesreveal that the terpolymer and its metal complexes can beactive against the selected bacterial and fungal strains Nearlyall of the compoundsmay suit well for drug delivery field afterchecking for their toxicology behaviour in thorough mannerThermal studies are also helpful to realize the standing capac-ity of the compounds which survive as antimicrobial coatingmaterials in various environmental conditions Because ofthe proven high stability nature and microbial preventioncapacity the BEF terpolymer and its Cu2+ Ni2+ and Zn2+complexes hold inadequate applications in biological fieldThe thermal stability of the terpolymer and its metal com-plexes was found greater From the thermodynamic andkinetic studies the abnormal low values of frequency factor(119885) indicate that the thermal decomposition reaction of BEFterpolymer and its metal complexes can be depicted as a slowreaction The BEF terpolymer and its metal complexes maybe following nearly a first order kinetics
Conflict of Interests
The authors certify that there is no conflict of interests withany financial organization regarding thematerial discussed inthe paper
Acknowledgments
The authors thank the Management and Principal ofOxford Engineering College Tiruchirappalli CoimbatoreInstitute of Technology Coimbatore Jamal Mohamed Col-lege (Autonomous) Tiruchirappalli Tamil Nadu and DrD Jeyakumar Scientist Central Electrochemical ResearchInstitute (CECRI-CSIR) Karaikudi Tamil Nadu for theirsupport and encouragement
References
[1] C U Pittman K S Ramachandran Jr and K R LowyerldquoSynthesis of fungicidal monomers polymers and latticesrdquoJournal of Coating Technology vol 54 pp 27ndash40 1982
[2] M N Patel J R Patel and D H Sutaria ldquoNovel co-ordinationpolychelatesrdquo Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry vol 24 no 8 pp 1297ndash1309 1994
[3] V V Ukey and H D Juneja ldquoSynthetic and spectroscopicstudies of chelate polymers involving azelaoyl bis-N-phenylhydroxamic acid with transition metal ionsrdquo Journal of AppliedPolymer Science vol 99 no 1 pp 273ndash278 2006
[4] S K-H Thiele and D R Wilson ldquoAlternate transition metalcomplex based diene polymerizationrdquo Polymer Reviews vol 43no 4 pp 581ndash628 2003
[5] N Nishat S Ahmad and T Ahamad ldquoSynthesis and character-ization of antibacterial polychelates of urea-formaldehyde resinwith Cr(III) Mn(II) Fe(III) Co(II) Ni(II) Cu(II) and Zn(II)metal ionsrdquo Journal of Applied Polymer Science vol 100 no 2pp 928ndash936 2006
[6] E Brzezinska G Koska and K Walczynski ldquoApplicationof thin-layer chromatographic data in quantitative structure-activity relationship assay of thiazole and benzothiazole deriva-tives with Hmdashantihistamine activityrdquo Journal of Chromatogra-phy A vol 1007 pp 145ndash155 2003
[7] M A R Ahamed and A R Burkanudeen ldquoMetal complexesof a novel terpolymer ligand synthesis spectral morphologythermal degradation kinetics and antimicrobial screeningrdquoJournal of Inorganic andOrganometallic Polymers andMaterialsvol 22 no 5 pp 1046ndash1061 2012
[8] B S Holla K V Malini V S Rao B K Sarojini and N SKumari ldquoSynthesis of some new 24-disubstituted thiazoles aspossible antibacterial and anti-inflammatory agentsrdquo EuropeanJournal of Medicinal Chemistry vol 38 no 3 pp 313ndash318 2003
[9] O I El-Sabbagh M M Baraka S M Ibrahim et al ldquoSynthesisand antiviral activity of new pyrazole and thiazole derivativesrdquoEuropean Journal of Medicinal Chemistry vol 44 no 9 pp3746ndash3753 2009
[10] A Andreani M Granaiola A Leoni A Locatelli R Morigiand M Rambaldi ldquoSynthesis and antitubercular activity ofimidazo[21-b]thiazolesrdquo European Journal of Medicinal Chem-istry vol 36 no 9 pp 743ndash746 2001
[11] E Yousif Y Farina K Kasar A Graisa and K Ayid ldquoCom-plexes of 2-thioacetic acid benzothiazole with somemetal ionsrdquoAmerican Journal of Applied Sciences vol 6 no 4 pp 582ndash5852009
[12] B P Mallikarjuna B S Sastry G V Suresh Kumar Y Rajen-draprasad S M Chandrashekar and K Sathisha ldquoSynthesis ofnew 4-isopropylthiazole hydrazide analogs and some derivedclubbed triazole oxadiazole ring systemsmdasha novel class ofpotential antibacterial antifungal and antitubercular agentsrdquoEuropean Journal of Medicinal Chemistry vol 44 pp 4739ndash4746 2009
[13] T Ahamad V Kumar and N Nishat ldquoNew class of anti-microbial agents synthesis characterization and anti-microbial activities of metal chelated polyureardquo Journal ofBiomedical Materials Research A vol 88 no 2 pp 288ndash2942009
[14] M V Patel J N Patel M B Dolia and R M Patel ldquoPolyether-ketones synthesis characterization and antimicrobial activityrdquoInternational Journal of Polymeric Materials and PolymericBiomaterials vol 54 no 11 pp 1059ndash1071 2005
[15] K R Alagawadi and S G Alegaon ldquoSynthesis characteriza-tion and antimicrobial activity evaluation of new 24-Thiazoli-dinediones bearing imidazo[21-b][134]thiadiazole moietyrdquoArabian Journal of Chemistry vol 4 no 4 pp 465ndash472 2011
[16] M Ashok B S Holla and N S Kumari ldquoConvenientone pot synthesis of some novel derivatives of thiazolo[23-b]dihydropyrimidinone possessing 4-methylthiophenyl moietyand evaluation of their antibacterial and antifungal activitiesrdquoEuropean Journal ofMedicinal Chemistry vol 42 no 3 pp 380ndash385 2007
16 Bioinorganic Chemistry and Applications
[17] T Ahamad V Kumar S Parveen and N Nishat ldquoIn vitroantibacterial and antifungal assay of poly-(ethylene oxamide-NN1015840-diacetate) and its polymer-metal complexesrdquo AppliedOrganometallic Chemistry vol 21 no 12 pp 1013ndash1021 2007
[18] R S Azarudeen M A R Ahamed and A R BurkanudeenldquoBiological and thermal investigations of polychelates derivedfrom a novel terpolymer ligandrdquo Journal of Polymer Researchvol 18 no 6 pp 1331ndash1341 2011
[19] R S Azarudeen and A R Burkanudeen ldquoSynthesis spectralmorphology thermal degradation kinetics and antibacterialstudies of terpolymermetal complexesrdquo Journal of Inorganic andOrganometallic Polymers and Materials vol 22 no 4 pp 791ndash806 2012
[20] R S Azarudeen and A R Burkanudeen ldquoStudies of newoligomer-metal complexes and their antibacterial activitiesrdquoPolymer International vol 62 no 3 pp 362ndash374 2013
[21] G S Devi A K Muthu D S Kumar S Rekha R Indhumathiand R Nandhini ldquoStudies on the antibacterial and antifungalactivities of the ethanolic extracts of Luffa cylindrica (Linn)fruitrdquo International Journal of Drug Development and Researchvol 1 pp 105ndash109 2013
[22] R M Silverstein and G C Bassler Spectrometric IdentificationofOrganic Compounds JohnWileyamp SonsNewYorkNYUSA2nd edition 1967
[23] Y-G Zhao H-Y Shen S-D Pan and M-Q Hu ldquoSyn-thesis characterization and properties of ethylenediamine-functionalized Fe
3O4magnetic polymers for removal of Cr(VI)
in wastewaterrdquo Journal of Hazardous Materials vol 182 no 1-3pp 295ndash302 2010
[24] Y R Sharma Elementary Organic Absorption Spectroscopy SChand amp Co Ltd New Delhi India 1980
[25] D Kivelson and R Neiman ldquoESR line shapes in glasses ofcopper complexesrdquoThe Journal of Chemical Physics vol 35 no1 pp 149ndash155 1961
[26] E Pretsch P Buhlmann and C Afflolter Structure Determi-nation of Organic Compounds Springer New York NY USA2000
[27] J L White Modern Magnetic Resonance Kluwer AcademicPress London UK 2006
[28] M M Patel M A Kapadia and J D Joshi ldquoThermal andcatalytic aspects of Ln(III) polymer-metal complexesrdquo PolymerInternational vol 58 no 7 pp 728ndash737 2009
[29] S Nanjundan C S J Selvamalar and R Jayakumar ldquoSynthesisand characterization of poly(3-acetyl-4-hydroxyphenyl acry-late) and its Cu(II) and Ni(II) complexesrdquo European PolymerJournal vol 40 no 10 pp 2313ndash2321 2004
[30] A V Nikolaev V A Logvinenco and L I Myachina ThermalAnalysis Academic Press New York NY USA 1969
[31] A Z El-Sonbati and M A Hefni ldquoPolymer complexes PartXXVImdashNovel mixed ligand poly-(5-vinyl salicylidene)-12-diaminobenzene complexesrdquo Polymer Degradation and Stabil-ity vol 43 no 1 pp 33ndash42 1994
[32] A S Aswar and N S Bhave ldquoThermal degradation studies ofsome new coordination polymersrdquo Polymer Degradation andStability vol 31 no 1 pp 115ndash124 1991
[33] T Ahamad V Kumar and N Nishat ldquoSynthesis characteri-zation and antimicrobial activity of transition metal chelatedthiourea-formaldehyde resinrdquo Polymer International vol 55no 12 pp 1398ndash1406 2006
[34] M M Patel M A Kapadia G P Patel and J D Joshi ldquoSynthe-sis characterization ion-exchange and antimicrobial study of
poly[(2-hydroxy-4-methoxybenzophenone) propylene] resinand its polychelates with lanthanides (III)rdquo Journal of AppliedPolymer Science vol 106 no 2 pp 1307ndash1317 2007
[35] M A Neelakantan S S Marriappan J Dharmaraja T Jeyaku-mar and K Muthukumaran ldquoSpectral XRD SEM and bio-logical activities of transition metal complexes of polydentateligands containing thiazole moietyrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 71 no 2 pp 628ndash635 2008
[36] G B Bagihalli S A Patil and P S Badami ldquoSynthesisphysicochemical investigation and biological studies of zinc(II)complexes with 124-triazole schiff basesrdquo Journal of the IranianChemical Society vol 6 no 2 pp 259ndash270 2009
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Inorganic ChemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Carbohydrate Chemistry
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
Physical Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom
Analytical Methods in Chemistry
Journal of
Volume 2014
Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
SpectroscopyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Medicinal ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chromatography Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Applied ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Theoretical ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Spectroscopy
Analytical ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Quantum Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Organic Chemistry International
ElectrochemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CatalystsJournal of
Bioinorganic Chemistry and Applications 13
log[g
(120572)T3]
minus95
minus90
minus85
minus80
minus75
10 15 20 25 30
Intercept = minus825
Ea = 1039
1000T (Kminus1)
(a)
log[g
(120572)T3]
minus78
minus80
minus82
minus84
minus86
minus88
minus90
minus92
minus94
minus96
minus76
Intercept = minus805
Ea = 1367
10 15 20 25 30
1000T (Kminus1)
(b)
log[g
(120572)T3]
minus77
minus78
minus79
minus80
minus81
minus82
minus83
minus84
minus85
minus86
minus87
minus88minus89
Intercept = minus849
Ea = 460
10 15 20 25 30
1000T (Kminus1)
(c)
minus78
minus80
minus82
minus84
minus86
minus7610 15 20 25 30
1000T (Kminus1)
log[g
(120572)T3]
Intercept = minus835
Ea = 1213
(d)
Figure 12 Freeman-Carroll plots (119864119886) of (a) BEF ligand (b) BEFndashCu (c) BEFndashNi and (d) BEFndashZn
Table 6 Activation energies calculated by Phadnis-Deshpande method
Reaction mechanism model Energy of activation (119864119886) (kJmol)
BEF ligand BEFminusCu BEFminusNi BEFminusZnPower law 60932 62642 59691 54312Power law 121864 125284 119382 108625Phase boundary (contracting sphere) 16497 16816 16174 15009Phase boundary (contracting cylinder) 25894 26436 25383 23466Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 12135 13830 11756 07447
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 08090 09220 07837 04964
Nucleation and nuclei growth(Avrami-Erofeev nuclei growth) 06067 06915 05878 03723
Valensi 2-dimensional diffusion 168354 171926 165034 152695Jander 3-dimensional diffusion 32995 33632 32349 30018Brounshtein-Ginstling 3-dimensional diffusion 56520 55015 55669 57981The values indicated in bold are closest to the 119864119886 value estimated by FC and SWmethods
14 Bioinorganic Chemistry and Applications
Table 7 Antibacterial activity of BEF ligand and its complexes
Compound Inhibition zone (mm)S sonnei E coli Klebsiella sp S aureus B subtilis S typhi
BEF ligand 15 13 13 14 15 12BEFndashCu 21 17 17 18 18 18BEFndashNi 18 15 18 17 20 15BEFndashZn 16 15 15 16 17 15Standard 26 28 26 25 27 28Control mdash mdash mdash mdash mdash mdashStandard amoxicillin control DMSO
Table 8 Antifungal activity of BEF ligand and its complexes
Compound Inhibition zone (mm)Aspergillus flavus Aspergillus niger Penicillium species Candida albicans Cryptococcus neoformans Mucorspecies
BEF ligand 14 12 12 13 11 12BEFndashCu 20 18 19 18 15 19BEFndashNi 17 14 17 15 13 13BEFndashZn 15 15 18 17 14 16Standard 20 21 19 21 18 22Control mdash mdash mdash mdash mdash mdashStandard fluconazole control DMSO
death There may be a rash resembling sunburn with peelingof skin The ligand and its complexes showed a humbleactivity against the growth of S aureus Bacillus subtilis arerod-shaped and nonpathogenic gram-positive bacteria TheBEF ligand and complexes showed superb activity againstthe growth of this bacterium Salmonella typhimurium is apathogenic gram-negative bacteria predominately found inthe intestinal lumen When the bacterial cells enter epithelialcells lining the intestine they cause host cell ruffling whichtemporarily damages the microvilli on the surface of the cellThis causes a rush of white blood cells into the mucosa andleads to diarrheaThe ligand and its metal complexes showeda moderate activity against the growth of the typhi species
A comparative account on the effect of antibacterialactivity against the chosen microbes indicates that the ligandand its three metal chelates show reasonable activity againstShigella sonnei (15 21 18 and 16mm) and Bacillus subtilis (1518 20 and 17mm) while the growth of other organisms ismoderately inhibited by the BEF ligand and its Cu2+ Ni2+and Zn2+ chelates The highest antibacterial action (21mm)has been observed for BEFndashCu2+ complex against Shigellasonnei
392 Antifungal Activity The antifungal activity of the BEFligand and its metal complexes has also given interestingresults and the growth inhibitions against the chosen fungalstrains are tabulated in Table 8 All the complexes and theirligand have an excellent activity against Aspergillus flavusa mold type fungal strain which may invade arteries of thelung or brain to cause infections and also produce a toxinAspergillus niger is one of the most common causes for
otomycosis The chelates and the ligand are found to havea reasonable activity for A niger Penicillium species causesinfection in humans and the resulting disease is known gener-ically as penicilliosis The ligand and the metal complexeshave wonderful activity against this species Further BEFndashCucomplex has a superior activity compared to the rest of othercomplexes Candida albicans is a diploid fungus and a causalagent of opportunistic oral and genital infections in humansand also emerged as an important cause of morbidity andmortality in immunocompromised patients The BEF ligandand its chelates possess a modest activity against C albicansover and above the standard Cryptococcus neoformans is anencapsulated yeast-like fungus that can live in both plantsand animals and cause lung infection The terpolymer ligandand its chelates have a fair activity against this fungal strainThe chelate compounds and the ligand havemoderate activityagainst Mucor species a filamentous fungus which causesseptic arthritis renal infections and pulmonary infections
From the antimicrobial results themetal complexes showhigher activity than their ligand which may be stronglydependent on the central metal ions and coordination num-bers metal chelates The higher activity due to the metal ionsshared with the donor atoms (N and S) of the thiazole ring ispresent in the ligand and the 120587-electron delocalization overthe chelate ring This effect increases the lipophilic characterof the metal ion which favors the permeation through thelipoid layers of the bacterial and fungal membranes [33 34]It is perceived that the factors such as solubility conductivitydipole moment and cell permeability may also contributeto the increased activity of the complexes [35 36] Fromthe results of the studies at 500 ppm concentration thecompounds establish better antimicrobial activity Hence it
Bioinorganic Chemistry and Applications 15
is an interesting result that a very low concentration of thecompound namely 500 ppm is enough to bring out aneffective inhibition against the chosen microbes
4 Conclusion
The synthesized 2-amino-6-nitro-benzothiazole-ethylene-diamine-formaldehyde terpolymer has acted as a ligandsuccessfully to form metal complexes The synthesized com-pounds were well characterized by various spectral andphysical analyses The morphological features suggest thatthe complexes are slightly more crystalline in nature thantheir parent ligandThe antibacterial and antifungal activitiesreveal that the terpolymer and its metal complexes can beactive against the selected bacterial and fungal strains Nearlyall of the compoundsmay suit well for drug delivery field afterchecking for their toxicology behaviour in thorough mannerThermal studies are also helpful to realize the standing capac-ity of the compounds which survive as antimicrobial coatingmaterials in various environmental conditions Because ofthe proven high stability nature and microbial preventioncapacity the BEF terpolymer and its Cu2+ Ni2+ and Zn2+complexes hold inadequate applications in biological fieldThe thermal stability of the terpolymer and its metal com-plexes was found greater From the thermodynamic andkinetic studies the abnormal low values of frequency factor(119885) indicate that the thermal decomposition reaction of BEFterpolymer and its metal complexes can be depicted as a slowreaction The BEF terpolymer and its metal complexes maybe following nearly a first order kinetics
Conflict of Interests
The authors certify that there is no conflict of interests withany financial organization regarding thematerial discussed inthe paper
Acknowledgments
The authors thank the Management and Principal ofOxford Engineering College Tiruchirappalli CoimbatoreInstitute of Technology Coimbatore Jamal Mohamed Col-lege (Autonomous) Tiruchirappalli Tamil Nadu and DrD Jeyakumar Scientist Central Electrochemical ResearchInstitute (CECRI-CSIR) Karaikudi Tamil Nadu for theirsupport and encouragement
References
[1] C U Pittman K S Ramachandran Jr and K R LowyerldquoSynthesis of fungicidal monomers polymers and latticesrdquoJournal of Coating Technology vol 54 pp 27ndash40 1982
[2] M N Patel J R Patel and D H Sutaria ldquoNovel co-ordinationpolychelatesrdquo Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry vol 24 no 8 pp 1297ndash1309 1994
[3] V V Ukey and H D Juneja ldquoSynthetic and spectroscopicstudies of chelate polymers involving azelaoyl bis-N-phenylhydroxamic acid with transition metal ionsrdquo Journal of AppliedPolymer Science vol 99 no 1 pp 273ndash278 2006
[4] S K-H Thiele and D R Wilson ldquoAlternate transition metalcomplex based diene polymerizationrdquo Polymer Reviews vol 43no 4 pp 581ndash628 2003
[5] N Nishat S Ahmad and T Ahamad ldquoSynthesis and character-ization of antibacterial polychelates of urea-formaldehyde resinwith Cr(III) Mn(II) Fe(III) Co(II) Ni(II) Cu(II) and Zn(II)metal ionsrdquo Journal of Applied Polymer Science vol 100 no 2pp 928ndash936 2006
[6] E Brzezinska G Koska and K Walczynski ldquoApplicationof thin-layer chromatographic data in quantitative structure-activity relationship assay of thiazole and benzothiazole deriva-tives with Hmdashantihistamine activityrdquo Journal of Chromatogra-phy A vol 1007 pp 145ndash155 2003
[7] M A R Ahamed and A R Burkanudeen ldquoMetal complexesof a novel terpolymer ligand synthesis spectral morphologythermal degradation kinetics and antimicrobial screeningrdquoJournal of Inorganic andOrganometallic Polymers andMaterialsvol 22 no 5 pp 1046ndash1061 2012
[8] B S Holla K V Malini V S Rao B K Sarojini and N SKumari ldquoSynthesis of some new 24-disubstituted thiazoles aspossible antibacterial and anti-inflammatory agentsrdquo EuropeanJournal of Medicinal Chemistry vol 38 no 3 pp 313ndash318 2003
[9] O I El-Sabbagh M M Baraka S M Ibrahim et al ldquoSynthesisand antiviral activity of new pyrazole and thiazole derivativesrdquoEuropean Journal of Medicinal Chemistry vol 44 no 9 pp3746ndash3753 2009
[10] A Andreani M Granaiola A Leoni A Locatelli R Morigiand M Rambaldi ldquoSynthesis and antitubercular activity ofimidazo[21-b]thiazolesrdquo European Journal of Medicinal Chem-istry vol 36 no 9 pp 743ndash746 2001
[11] E Yousif Y Farina K Kasar A Graisa and K Ayid ldquoCom-plexes of 2-thioacetic acid benzothiazole with somemetal ionsrdquoAmerican Journal of Applied Sciences vol 6 no 4 pp 582ndash5852009
[12] B P Mallikarjuna B S Sastry G V Suresh Kumar Y Rajen-draprasad S M Chandrashekar and K Sathisha ldquoSynthesis ofnew 4-isopropylthiazole hydrazide analogs and some derivedclubbed triazole oxadiazole ring systemsmdasha novel class ofpotential antibacterial antifungal and antitubercular agentsrdquoEuropean Journal of Medicinal Chemistry vol 44 pp 4739ndash4746 2009
[13] T Ahamad V Kumar and N Nishat ldquoNew class of anti-microbial agents synthesis characterization and anti-microbial activities of metal chelated polyureardquo Journal ofBiomedical Materials Research A vol 88 no 2 pp 288ndash2942009
[14] M V Patel J N Patel M B Dolia and R M Patel ldquoPolyether-ketones synthesis characterization and antimicrobial activityrdquoInternational Journal of Polymeric Materials and PolymericBiomaterials vol 54 no 11 pp 1059ndash1071 2005
[15] K R Alagawadi and S G Alegaon ldquoSynthesis characteriza-tion and antimicrobial activity evaluation of new 24-Thiazoli-dinediones bearing imidazo[21-b][134]thiadiazole moietyrdquoArabian Journal of Chemistry vol 4 no 4 pp 465ndash472 2011
[16] M Ashok B S Holla and N S Kumari ldquoConvenientone pot synthesis of some novel derivatives of thiazolo[23-b]dihydropyrimidinone possessing 4-methylthiophenyl moietyand evaluation of their antibacterial and antifungal activitiesrdquoEuropean Journal ofMedicinal Chemistry vol 42 no 3 pp 380ndash385 2007
16 Bioinorganic Chemistry and Applications
[17] T Ahamad V Kumar S Parveen and N Nishat ldquoIn vitroantibacterial and antifungal assay of poly-(ethylene oxamide-NN1015840-diacetate) and its polymer-metal complexesrdquo AppliedOrganometallic Chemistry vol 21 no 12 pp 1013ndash1021 2007
[18] R S Azarudeen M A R Ahamed and A R BurkanudeenldquoBiological and thermal investigations of polychelates derivedfrom a novel terpolymer ligandrdquo Journal of Polymer Researchvol 18 no 6 pp 1331ndash1341 2011
[19] R S Azarudeen and A R Burkanudeen ldquoSynthesis spectralmorphology thermal degradation kinetics and antibacterialstudies of terpolymermetal complexesrdquo Journal of Inorganic andOrganometallic Polymers and Materials vol 22 no 4 pp 791ndash806 2012
[20] R S Azarudeen and A R Burkanudeen ldquoStudies of newoligomer-metal complexes and their antibacterial activitiesrdquoPolymer International vol 62 no 3 pp 362ndash374 2013
[21] G S Devi A K Muthu D S Kumar S Rekha R Indhumathiand R Nandhini ldquoStudies on the antibacterial and antifungalactivities of the ethanolic extracts of Luffa cylindrica (Linn)fruitrdquo International Journal of Drug Development and Researchvol 1 pp 105ndash109 2013
[22] R M Silverstein and G C Bassler Spectrometric IdentificationofOrganic Compounds JohnWileyamp SonsNewYorkNYUSA2nd edition 1967
[23] Y-G Zhao H-Y Shen S-D Pan and M-Q Hu ldquoSyn-thesis characterization and properties of ethylenediamine-functionalized Fe
3O4magnetic polymers for removal of Cr(VI)
in wastewaterrdquo Journal of Hazardous Materials vol 182 no 1-3pp 295ndash302 2010
[24] Y R Sharma Elementary Organic Absorption Spectroscopy SChand amp Co Ltd New Delhi India 1980
[25] D Kivelson and R Neiman ldquoESR line shapes in glasses ofcopper complexesrdquoThe Journal of Chemical Physics vol 35 no1 pp 149ndash155 1961
[26] E Pretsch P Buhlmann and C Afflolter Structure Determi-nation of Organic Compounds Springer New York NY USA2000
[27] J L White Modern Magnetic Resonance Kluwer AcademicPress London UK 2006
[28] M M Patel M A Kapadia and J D Joshi ldquoThermal andcatalytic aspects of Ln(III) polymer-metal complexesrdquo PolymerInternational vol 58 no 7 pp 728ndash737 2009
[29] S Nanjundan C S J Selvamalar and R Jayakumar ldquoSynthesisand characterization of poly(3-acetyl-4-hydroxyphenyl acry-late) and its Cu(II) and Ni(II) complexesrdquo European PolymerJournal vol 40 no 10 pp 2313ndash2321 2004
[30] A V Nikolaev V A Logvinenco and L I Myachina ThermalAnalysis Academic Press New York NY USA 1969
[31] A Z El-Sonbati and M A Hefni ldquoPolymer complexes PartXXVImdashNovel mixed ligand poly-(5-vinyl salicylidene)-12-diaminobenzene complexesrdquo Polymer Degradation and Stabil-ity vol 43 no 1 pp 33ndash42 1994
[32] A S Aswar and N S Bhave ldquoThermal degradation studies ofsome new coordination polymersrdquo Polymer Degradation andStability vol 31 no 1 pp 115ndash124 1991
[33] T Ahamad V Kumar and N Nishat ldquoSynthesis characteri-zation and antimicrobial activity of transition metal chelatedthiourea-formaldehyde resinrdquo Polymer International vol 55no 12 pp 1398ndash1406 2006
[34] M M Patel M A Kapadia G P Patel and J D Joshi ldquoSynthe-sis characterization ion-exchange and antimicrobial study of
poly[(2-hydroxy-4-methoxybenzophenone) propylene] resinand its polychelates with lanthanides (III)rdquo Journal of AppliedPolymer Science vol 106 no 2 pp 1307ndash1317 2007
[35] M A Neelakantan S S Marriappan J Dharmaraja T Jeyaku-mar and K Muthukumaran ldquoSpectral XRD SEM and bio-logical activities of transition metal complexes of polydentateligands containing thiazole moietyrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 71 no 2 pp 628ndash635 2008
[36] G B Bagihalli S A Patil and P S Badami ldquoSynthesisphysicochemical investigation and biological studies of zinc(II)complexes with 124-triazole schiff basesrdquo Journal of the IranianChemical Society vol 6 no 2 pp 259ndash270 2009
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Inorganic ChemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Carbohydrate Chemistry
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
Physical Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom
Analytical Methods in Chemistry
Journal of
Volume 2014
Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
SpectroscopyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Medicinal ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chromatography Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Applied ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Theoretical ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Spectroscopy
Analytical ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Quantum Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Organic Chemistry International
ElectrochemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CatalystsJournal of
14 Bioinorganic Chemistry and Applications
Table 7 Antibacterial activity of BEF ligand and its complexes
Compound Inhibition zone (mm)S sonnei E coli Klebsiella sp S aureus B subtilis S typhi
BEF ligand 15 13 13 14 15 12BEFndashCu 21 17 17 18 18 18BEFndashNi 18 15 18 17 20 15BEFndashZn 16 15 15 16 17 15Standard 26 28 26 25 27 28Control mdash mdash mdash mdash mdash mdashStandard amoxicillin control DMSO
Table 8 Antifungal activity of BEF ligand and its complexes
Compound Inhibition zone (mm)Aspergillus flavus Aspergillus niger Penicillium species Candida albicans Cryptococcus neoformans Mucorspecies
BEF ligand 14 12 12 13 11 12BEFndashCu 20 18 19 18 15 19BEFndashNi 17 14 17 15 13 13BEFndashZn 15 15 18 17 14 16Standard 20 21 19 21 18 22Control mdash mdash mdash mdash mdash mdashStandard fluconazole control DMSO
death There may be a rash resembling sunburn with peelingof skin The ligand and its complexes showed a humbleactivity against the growth of S aureus Bacillus subtilis arerod-shaped and nonpathogenic gram-positive bacteria TheBEF ligand and complexes showed superb activity againstthe growth of this bacterium Salmonella typhimurium is apathogenic gram-negative bacteria predominately found inthe intestinal lumen When the bacterial cells enter epithelialcells lining the intestine they cause host cell ruffling whichtemporarily damages the microvilli on the surface of the cellThis causes a rush of white blood cells into the mucosa andleads to diarrheaThe ligand and its metal complexes showeda moderate activity against the growth of the typhi species
A comparative account on the effect of antibacterialactivity against the chosen microbes indicates that the ligandand its three metal chelates show reasonable activity againstShigella sonnei (15 21 18 and 16mm) and Bacillus subtilis (1518 20 and 17mm) while the growth of other organisms ismoderately inhibited by the BEF ligand and its Cu2+ Ni2+and Zn2+ chelates The highest antibacterial action (21mm)has been observed for BEFndashCu2+ complex against Shigellasonnei
392 Antifungal Activity The antifungal activity of the BEFligand and its metal complexes has also given interestingresults and the growth inhibitions against the chosen fungalstrains are tabulated in Table 8 All the complexes and theirligand have an excellent activity against Aspergillus flavusa mold type fungal strain which may invade arteries of thelung or brain to cause infections and also produce a toxinAspergillus niger is one of the most common causes for
otomycosis The chelates and the ligand are found to havea reasonable activity for A niger Penicillium species causesinfection in humans and the resulting disease is known gener-ically as penicilliosis The ligand and the metal complexeshave wonderful activity against this species Further BEFndashCucomplex has a superior activity compared to the rest of othercomplexes Candida albicans is a diploid fungus and a causalagent of opportunistic oral and genital infections in humansand also emerged as an important cause of morbidity andmortality in immunocompromised patients The BEF ligandand its chelates possess a modest activity against C albicansover and above the standard Cryptococcus neoformans is anencapsulated yeast-like fungus that can live in both plantsand animals and cause lung infection The terpolymer ligandand its chelates have a fair activity against this fungal strainThe chelate compounds and the ligand havemoderate activityagainst Mucor species a filamentous fungus which causesseptic arthritis renal infections and pulmonary infections
From the antimicrobial results themetal complexes showhigher activity than their ligand which may be stronglydependent on the central metal ions and coordination num-bers metal chelates The higher activity due to the metal ionsshared with the donor atoms (N and S) of the thiazole ring ispresent in the ligand and the 120587-electron delocalization overthe chelate ring This effect increases the lipophilic characterof the metal ion which favors the permeation through thelipoid layers of the bacterial and fungal membranes [33 34]It is perceived that the factors such as solubility conductivitydipole moment and cell permeability may also contributeto the increased activity of the complexes [35 36] Fromthe results of the studies at 500 ppm concentration thecompounds establish better antimicrobial activity Hence it
Bioinorganic Chemistry and Applications 15
is an interesting result that a very low concentration of thecompound namely 500 ppm is enough to bring out aneffective inhibition against the chosen microbes
4 Conclusion
The synthesized 2-amino-6-nitro-benzothiazole-ethylene-diamine-formaldehyde terpolymer has acted as a ligandsuccessfully to form metal complexes The synthesized com-pounds were well characterized by various spectral andphysical analyses The morphological features suggest thatthe complexes are slightly more crystalline in nature thantheir parent ligandThe antibacterial and antifungal activitiesreveal that the terpolymer and its metal complexes can beactive against the selected bacterial and fungal strains Nearlyall of the compoundsmay suit well for drug delivery field afterchecking for their toxicology behaviour in thorough mannerThermal studies are also helpful to realize the standing capac-ity of the compounds which survive as antimicrobial coatingmaterials in various environmental conditions Because ofthe proven high stability nature and microbial preventioncapacity the BEF terpolymer and its Cu2+ Ni2+ and Zn2+complexes hold inadequate applications in biological fieldThe thermal stability of the terpolymer and its metal com-plexes was found greater From the thermodynamic andkinetic studies the abnormal low values of frequency factor(119885) indicate that the thermal decomposition reaction of BEFterpolymer and its metal complexes can be depicted as a slowreaction The BEF terpolymer and its metal complexes maybe following nearly a first order kinetics
Conflict of Interests
The authors certify that there is no conflict of interests withany financial organization regarding thematerial discussed inthe paper
Acknowledgments
The authors thank the Management and Principal ofOxford Engineering College Tiruchirappalli CoimbatoreInstitute of Technology Coimbatore Jamal Mohamed Col-lege (Autonomous) Tiruchirappalli Tamil Nadu and DrD Jeyakumar Scientist Central Electrochemical ResearchInstitute (CECRI-CSIR) Karaikudi Tamil Nadu for theirsupport and encouragement
References
[1] C U Pittman K S Ramachandran Jr and K R LowyerldquoSynthesis of fungicidal monomers polymers and latticesrdquoJournal of Coating Technology vol 54 pp 27ndash40 1982
[2] M N Patel J R Patel and D H Sutaria ldquoNovel co-ordinationpolychelatesrdquo Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry vol 24 no 8 pp 1297ndash1309 1994
[3] V V Ukey and H D Juneja ldquoSynthetic and spectroscopicstudies of chelate polymers involving azelaoyl bis-N-phenylhydroxamic acid with transition metal ionsrdquo Journal of AppliedPolymer Science vol 99 no 1 pp 273ndash278 2006
[4] S K-H Thiele and D R Wilson ldquoAlternate transition metalcomplex based diene polymerizationrdquo Polymer Reviews vol 43no 4 pp 581ndash628 2003
[5] N Nishat S Ahmad and T Ahamad ldquoSynthesis and character-ization of antibacterial polychelates of urea-formaldehyde resinwith Cr(III) Mn(II) Fe(III) Co(II) Ni(II) Cu(II) and Zn(II)metal ionsrdquo Journal of Applied Polymer Science vol 100 no 2pp 928ndash936 2006
[6] E Brzezinska G Koska and K Walczynski ldquoApplicationof thin-layer chromatographic data in quantitative structure-activity relationship assay of thiazole and benzothiazole deriva-tives with Hmdashantihistamine activityrdquo Journal of Chromatogra-phy A vol 1007 pp 145ndash155 2003
[7] M A R Ahamed and A R Burkanudeen ldquoMetal complexesof a novel terpolymer ligand synthesis spectral morphologythermal degradation kinetics and antimicrobial screeningrdquoJournal of Inorganic andOrganometallic Polymers andMaterialsvol 22 no 5 pp 1046ndash1061 2012
[8] B S Holla K V Malini V S Rao B K Sarojini and N SKumari ldquoSynthesis of some new 24-disubstituted thiazoles aspossible antibacterial and anti-inflammatory agentsrdquo EuropeanJournal of Medicinal Chemistry vol 38 no 3 pp 313ndash318 2003
[9] O I El-Sabbagh M M Baraka S M Ibrahim et al ldquoSynthesisand antiviral activity of new pyrazole and thiazole derivativesrdquoEuropean Journal of Medicinal Chemistry vol 44 no 9 pp3746ndash3753 2009
[10] A Andreani M Granaiola A Leoni A Locatelli R Morigiand M Rambaldi ldquoSynthesis and antitubercular activity ofimidazo[21-b]thiazolesrdquo European Journal of Medicinal Chem-istry vol 36 no 9 pp 743ndash746 2001
[11] E Yousif Y Farina K Kasar A Graisa and K Ayid ldquoCom-plexes of 2-thioacetic acid benzothiazole with somemetal ionsrdquoAmerican Journal of Applied Sciences vol 6 no 4 pp 582ndash5852009
[12] B P Mallikarjuna B S Sastry G V Suresh Kumar Y Rajen-draprasad S M Chandrashekar and K Sathisha ldquoSynthesis ofnew 4-isopropylthiazole hydrazide analogs and some derivedclubbed triazole oxadiazole ring systemsmdasha novel class ofpotential antibacterial antifungal and antitubercular agentsrdquoEuropean Journal of Medicinal Chemistry vol 44 pp 4739ndash4746 2009
[13] T Ahamad V Kumar and N Nishat ldquoNew class of anti-microbial agents synthesis characterization and anti-microbial activities of metal chelated polyureardquo Journal ofBiomedical Materials Research A vol 88 no 2 pp 288ndash2942009
[14] M V Patel J N Patel M B Dolia and R M Patel ldquoPolyether-ketones synthesis characterization and antimicrobial activityrdquoInternational Journal of Polymeric Materials and PolymericBiomaterials vol 54 no 11 pp 1059ndash1071 2005
[15] K R Alagawadi and S G Alegaon ldquoSynthesis characteriza-tion and antimicrobial activity evaluation of new 24-Thiazoli-dinediones bearing imidazo[21-b][134]thiadiazole moietyrdquoArabian Journal of Chemistry vol 4 no 4 pp 465ndash472 2011
[16] M Ashok B S Holla and N S Kumari ldquoConvenientone pot synthesis of some novel derivatives of thiazolo[23-b]dihydropyrimidinone possessing 4-methylthiophenyl moietyand evaluation of their antibacterial and antifungal activitiesrdquoEuropean Journal ofMedicinal Chemistry vol 42 no 3 pp 380ndash385 2007
16 Bioinorganic Chemistry and Applications
[17] T Ahamad V Kumar S Parveen and N Nishat ldquoIn vitroantibacterial and antifungal assay of poly-(ethylene oxamide-NN1015840-diacetate) and its polymer-metal complexesrdquo AppliedOrganometallic Chemistry vol 21 no 12 pp 1013ndash1021 2007
[18] R S Azarudeen M A R Ahamed and A R BurkanudeenldquoBiological and thermal investigations of polychelates derivedfrom a novel terpolymer ligandrdquo Journal of Polymer Researchvol 18 no 6 pp 1331ndash1341 2011
[19] R S Azarudeen and A R Burkanudeen ldquoSynthesis spectralmorphology thermal degradation kinetics and antibacterialstudies of terpolymermetal complexesrdquo Journal of Inorganic andOrganometallic Polymers and Materials vol 22 no 4 pp 791ndash806 2012
[20] R S Azarudeen and A R Burkanudeen ldquoStudies of newoligomer-metal complexes and their antibacterial activitiesrdquoPolymer International vol 62 no 3 pp 362ndash374 2013
[21] G S Devi A K Muthu D S Kumar S Rekha R Indhumathiand R Nandhini ldquoStudies on the antibacterial and antifungalactivities of the ethanolic extracts of Luffa cylindrica (Linn)fruitrdquo International Journal of Drug Development and Researchvol 1 pp 105ndash109 2013
[22] R M Silverstein and G C Bassler Spectrometric IdentificationofOrganic Compounds JohnWileyamp SonsNewYorkNYUSA2nd edition 1967
[23] Y-G Zhao H-Y Shen S-D Pan and M-Q Hu ldquoSyn-thesis characterization and properties of ethylenediamine-functionalized Fe
3O4magnetic polymers for removal of Cr(VI)
in wastewaterrdquo Journal of Hazardous Materials vol 182 no 1-3pp 295ndash302 2010
[24] Y R Sharma Elementary Organic Absorption Spectroscopy SChand amp Co Ltd New Delhi India 1980
[25] D Kivelson and R Neiman ldquoESR line shapes in glasses ofcopper complexesrdquoThe Journal of Chemical Physics vol 35 no1 pp 149ndash155 1961
[26] E Pretsch P Buhlmann and C Afflolter Structure Determi-nation of Organic Compounds Springer New York NY USA2000
[27] J L White Modern Magnetic Resonance Kluwer AcademicPress London UK 2006
[28] M M Patel M A Kapadia and J D Joshi ldquoThermal andcatalytic aspects of Ln(III) polymer-metal complexesrdquo PolymerInternational vol 58 no 7 pp 728ndash737 2009
[29] S Nanjundan C S J Selvamalar and R Jayakumar ldquoSynthesisand characterization of poly(3-acetyl-4-hydroxyphenyl acry-late) and its Cu(II) and Ni(II) complexesrdquo European PolymerJournal vol 40 no 10 pp 2313ndash2321 2004
[30] A V Nikolaev V A Logvinenco and L I Myachina ThermalAnalysis Academic Press New York NY USA 1969
[31] A Z El-Sonbati and M A Hefni ldquoPolymer complexes PartXXVImdashNovel mixed ligand poly-(5-vinyl salicylidene)-12-diaminobenzene complexesrdquo Polymer Degradation and Stabil-ity vol 43 no 1 pp 33ndash42 1994
[32] A S Aswar and N S Bhave ldquoThermal degradation studies ofsome new coordination polymersrdquo Polymer Degradation andStability vol 31 no 1 pp 115ndash124 1991
[33] T Ahamad V Kumar and N Nishat ldquoSynthesis characteri-zation and antimicrobial activity of transition metal chelatedthiourea-formaldehyde resinrdquo Polymer International vol 55no 12 pp 1398ndash1406 2006
[34] M M Patel M A Kapadia G P Patel and J D Joshi ldquoSynthe-sis characterization ion-exchange and antimicrobial study of
poly[(2-hydroxy-4-methoxybenzophenone) propylene] resinand its polychelates with lanthanides (III)rdquo Journal of AppliedPolymer Science vol 106 no 2 pp 1307ndash1317 2007
[35] M A Neelakantan S S Marriappan J Dharmaraja T Jeyaku-mar and K Muthukumaran ldquoSpectral XRD SEM and bio-logical activities of transition metal complexes of polydentateligands containing thiazole moietyrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 71 no 2 pp 628ndash635 2008
[36] G B Bagihalli S A Patil and P S Badami ldquoSynthesisphysicochemical investigation and biological studies of zinc(II)complexes with 124-triazole schiff basesrdquo Journal of the IranianChemical Society vol 6 no 2 pp 259ndash270 2009
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Inorganic ChemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Carbohydrate Chemistry
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
Physical Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom
Analytical Methods in Chemistry
Journal of
Volume 2014
Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
SpectroscopyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Medicinal ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chromatography Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Applied ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Theoretical ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Spectroscopy
Analytical ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Quantum Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Organic Chemistry International
ElectrochemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CatalystsJournal of
Bioinorganic Chemistry and Applications 15
is an interesting result that a very low concentration of thecompound namely 500 ppm is enough to bring out aneffective inhibition against the chosen microbes
4 Conclusion
The synthesized 2-amino-6-nitro-benzothiazole-ethylene-diamine-formaldehyde terpolymer has acted as a ligandsuccessfully to form metal complexes The synthesized com-pounds were well characterized by various spectral andphysical analyses The morphological features suggest thatthe complexes are slightly more crystalline in nature thantheir parent ligandThe antibacterial and antifungal activitiesreveal that the terpolymer and its metal complexes can beactive against the selected bacterial and fungal strains Nearlyall of the compoundsmay suit well for drug delivery field afterchecking for their toxicology behaviour in thorough mannerThermal studies are also helpful to realize the standing capac-ity of the compounds which survive as antimicrobial coatingmaterials in various environmental conditions Because ofthe proven high stability nature and microbial preventioncapacity the BEF terpolymer and its Cu2+ Ni2+ and Zn2+complexes hold inadequate applications in biological fieldThe thermal stability of the terpolymer and its metal com-plexes was found greater From the thermodynamic andkinetic studies the abnormal low values of frequency factor(119885) indicate that the thermal decomposition reaction of BEFterpolymer and its metal complexes can be depicted as a slowreaction The BEF terpolymer and its metal complexes maybe following nearly a first order kinetics
Conflict of Interests
The authors certify that there is no conflict of interests withany financial organization regarding thematerial discussed inthe paper
Acknowledgments
The authors thank the Management and Principal ofOxford Engineering College Tiruchirappalli CoimbatoreInstitute of Technology Coimbatore Jamal Mohamed Col-lege (Autonomous) Tiruchirappalli Tamil Nadu and DrD Jeyakumar Scientist Central Electrochemical ResearchInstitute (CECRI-CSIR) Karaikudi Tamil Nadu for theirsupport and encouragement
References
[1] C U Pittman K S Ramachandran Jr and K R LowyerldquoSynthesis of fungicidal monomers polymers and latticesrdquoJournal of Coating Technology vol 54 pp 27ndash40 1982
[2] M N Patel J R Patel and D H Sutaria ldquoNovel co-ordinationpolychelatesrdquo Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry vol 24 no 8 pp 1297ndash1309 1994
[3] V V Ukey and H D Juneja ldquoSynthetic and spectroscopicstudies of chelate polymers involving azelaoyl bis-N-phenylhydroxamic acid with transition metal ionsrdquo Journal of AppliedPolymer Science vol 99 no 1 pp 273ndash278 2006
[4] S K-H Thiele and D R Wilson ldquoAlternate transition metalcomplex based diene polymerizationrdquo Polymer Reviews vol 43no 4 pp 581ndash628 2003
[5] N Nishat S Ahmad and T Ahamad ldquoSynthesis and character-ization of antibacterial polychelates of urea-formaldehyde resinwith Cr(III) Mn(II) Fe(III) Co(II) Ni(II) Cu(II) and Zn(II)metal ionsrdquo Journal of Applied Polymer Science vol 100 no 2pp 928ndash936 2006
[6] E Brzezinska G Koska and K Walczynski ldquoApplicationof thin-layer chromatographic data in quantitative structure-activity relationship assay of thiazole and benzothiazole deriva-tives with Hmdashantihistamine activityrdquo Journal of Chromatogra-phy A vol 1007 pp 145ndash155 2003
[7] M A R Ahamed and A R Burkanudeen ldquoMetal complexesof a novel terpolymer ligand synthesis spectral morphologythermal degradation kinetics and antimicrobial screeningrdquoJournal of Inorganic andOrganometallic Polymers andMaterialsvol 22 no 5 pp 1046ndash1061 2012
[8] B S Holla K V Malini V S Rao B K Sarojini and N SKumari ldquoSynthesis of some new 24-disubstituted thiazoles aspossible antibacterial and anti-inflammatory agentsrdquo EuropeanJournal of Medicinal Chemistry vol 38 no 3 pp 313ndash318 2003
[9] O I El-Sabbagh M M Baraka S M Ibrahim et al ldquoSynthesisand antiviral activity of new pyrazole and thiazole derivativesrdquoEuropean Journal of Medicinal Chemistry vol 44 no 9 pp3746ndash3753 2009
[10] A Andreani M Granaiola A Leoni A Locatelli R Morigiand M Rambaldi ldquoSynthesis and antitubercular activity ofimidazo[21-b]thiazolesrdquo European Journal of Medicinal Chem-istry vol 36 no 9 pp 743ndash746 2001
[11] E Yousif Y Farina K Kasar A Graisa and K Ayid ldquoCom-plexes of 2-thioacetic acid benzothiazole with somemetal ionsrdquoAmerican Journal of Applied Sciences vol 6 no 4 pp 582ndash5852009
[12] B P Mallikarjuna B S Sastry G V Suresh Kumar Y Rajen-draprasad S M Chandrashekar and K Sathisha ldquoSynthesis ofnew 4-isopropylthiazole hydrazide analogs and some derivedclubbed triazole oxadiazole ring systemsmdasha novel class ofpotential antibacterial antifungal and antitubercular agentsrdquoEuropean Journal of Medicinal Chemistry vol 44 pp 4739ndash4746 2009
[13] T Ahamad V Kumar and N Nishat ldquoNew class of anti-microbial agents synthesis characterization and anti-microbial activities of metal chelated polyureardquo Journal ofBiomedical Materials Research A vol 88 no 2 pp 288ndash2942009
[14] M V Patel J N Patel M B Dolia and R M Patel ldquoPolyether-ketones synthesis characterization and antimicrobial activityrdquoInternational Journal of Polymeric Materials and PolymericBiomaterials vol 54 no 11 pp 1059ndash1071 2005
[15] K R Alagawadi and S G Alegaon ldquoSynthesis characteriza-tion and antimicrobial activity evaluation of new 24-Thiazoli-dinediones bearing imidazo[21-b][134]thiadiazole moietyrdquoArabian Journal of Chemistry vol 4 no 4 pp 465ndash472 2011
[16] M Ashok B S Holla and N S Kumari ldquoConvenientone pot synthesis of some novel derivatives of thiazolo[23-b]dihydropyrimidinone possessing 4-methylthiophenyl moietyand evaluation of their antibacterial and antifungal activitiesrdquoEuropean Journal ofMedicinal Chemistry vol 42 no 3 pp 380ndash385 2007
16 Bioinorganic Chemistry and Applications
[17] T Ahamad V Kumar S Parveen and N Nishat ldquoIn vitroantibacterial and antifungal assay of poly-(ethylene oxamide-NN1015840-diacetate) and its polymer-metal complexesrdquo AppliedOrganometallic Chemistry vol 21 no 12 pp 1013ndash1021 2007
[18] R S Azarudeen M A R Ahamed and A R BurkanudeenldquoBiological and thermal investigations of polychelates derivedfrom a novel terpolymer ligandrdquo Journal of Polymer Researchvol 18 no 6 pp 1331ndash1341 2011
[19] R S Azarudeen and A R Burkanudeen ldquoSynthesis spectralmorphology thermal degradation kinetics and antibacterialstudies of terpolymermetal complexesrdquo Journal of Inorganic andOrganometallic Polymers and Materials vol 22 no 4 pp 791ndash806 2012
[20] R S Azarudeen and A R Burkanudeen ldquoStudies of newoligomer-metal complexes and their antibacterial activitiesrdquoPolymer International vol 62 no 3 pp 362ndash374 2013
[21] G S Devi A K Muthu D S Kumar S Rekha R Indhumathiand R Nandhini ldquoStudies on the antibacterial and antifungalactivities of the ethanolic extracts of Luffa cylindrica (Linn)fruitrdquo International Journal of Drug Development and Researchvol 1 pp 105ndash109 2013
[22] R M Silverstein and G C Bassler Spectrometric IdentificationofOrganic Compounds JohnWileyamp SonsNewYorkNYUSA2nd edition 1967
[23] Y-G Zhao H-Y Shen S-D Pan and M-Q Hu ldquoSyn-thesis characterization and properties of ethylenediamine-functionalized Fe
3O4magnetic polymers for removal of Cr(VI)
in wastewaterrdquo Journal of Hazardous Materials vol 182 no 1-3pp 295ndash302 2010
[24] Y R Sharma Elementary Organic Absorption Spectroscopy SChand amp Co Ltd New Delhi India 1980
[25] D Kivelson and R Neiman ldquoESR line shapes in glasses ofcopper complexesrdquoThe Journal of Chemical Physics vol 35 no1 pp 149ndash155 1961
[26] E Pretsch P Buhlmann and C Afflolter Structure Determi-nation of Organic Compounds Springer New York NY USA2000
[27] J L White Modern Magnetic Resonance Kluwer AcademicPress London UK 2006
[28] M M Patel M A Kapadia and J D Joshi ldquoThermal andcatalytic aspects of Ln(III) polymer-metal complexesrdquo PolymerInternational vol 58 no 7 pp 728ndash737 2009
[29] S Nanjundan C S J Selvamalar and R Jayakumar ldquoSynthesisand characterization of poly(3-acetyl-4-hydroxyphenyl acry-late) and its Cu(II) and Ni(II) complexesrdquo European PolymerJournal vol 40 no 10 pp 2313ndash2321 2004
[30] A V Nikolaev V A Logvinenco and L I Myachina ThermalAnalysis Academic Press New York NY USA 1969
[31] A Z El-Sonbati and M A Hefni ldquoPolymer complexes PartXXVImdashNovel mixed ligand poly-(5-vinyl salicylidene)-12-diaminobenzene complexesrdquo Polymer Degradation and Stabil-ity vol 43 no 1 pp 33ndash42 1994
[32] A S Aswar and N S Bhave ldquoThermal degradation studies ofsome new coordination polymersrdquo Polymer Degradation andStability vol 31 no 1 pp 115ndash124 1991
[33] T Ahamad V Kumar and N Nishat ldquoSynthesis characteri-zation and antimicrobial activity of transition metal chelatedthiourea-formaldehyde resinrdquo Polymer International vol 55no 12 pp 1398ndash1406 2006
[34] M M Patel M A Kapadia G P Patel and J D Joshi ldquoSynthe-sis characterization ion-exchange and antimicrobial study of
poly[(2-hydroxy-4-methoxybenzophenone) propylene] resinand its polychelates with lanthanides (III)rdquo Journal of AppliedPolymer Science vol 106 no 2 pp 1307ndash1317 2007
[35] M A Neelakantan S S Marriappan J Dharmaraja T Jeyaku-mar and K Muthukumaran ldquoSpectral XRD SEM and bio-logical activities of transition metal complexes of polydentateligands containing thiazole moietyrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 71 no 2 pp 628ndash635 2008
[36] G B Bagihalli S A Patil and P S Badami ldquoSynthesisphysicochemical investigation and biological studies of zinc(II)complexes with 124-triazole schiff basesrdquo Journal of the IranianChemical Society vol 6 no 2 pp 259ndash270 2009
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Inorganic ChemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Carbohydrate Chemistry
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
Physical Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom
Analytical Methods in Chemistry
Journal of
Volume 2014
Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
SpectroscopyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Medicinal ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chromatography Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Applied ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Theoretical ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Spectroscopy
Analytical ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Quantum Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Organic Chemistry International
ElectrochemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CatalystsJournal of
16 Bioinorganic Chemistry and Applications
[17] T Ahamad V Kumar S Parveen and N Nishat ldquoIn vitroantibacterial and antifungal assay of poly-(ethylene oxamide-NN1015840-diacetate) and its polymer-metal complexesrdquo AppliedOrganometallic Chemistry vol 21 no 12 pp 1013ndash1021 2007
[18] R S Azarudeen M A R Ahamed and A R BurkanudeenldquoBiological and thermal investigations of polychelates derivedfrom a novel terpolymer ligandrdquo Journal of Polymer Researchvol 18 no 6 pp 1331ndash1341 2011
[19] R S Azarudeen and A R Burkanudeen ldquoSynthesis spectralmorphology thermal degradation kinetics and antibacterialstudies of terpolymermetal complexesrdquo Journal of Inorganic andOrganometallic Polymers and Materials vol 22 no 4 pp 791ndash806 2012
[20] R S Azarudeen and A R Burkanudeen ldquoStudies of newoligomer-metal complexes and their antibacterial activitiesrdquoPolymer International vol 62 no 3 pp 362ndash374 2013
[21] G S Devi A K Muthu D S Kumar S Rekha R Indhumathiand R Nandhini ldquoStudies on the antibacterial and antifungalactivities of the ethanolic extracts of Luffa cylindrica (Linn)fruitrdquo International Journal of Drug Development and Researchvol 1 pp 105ndash109 2013
[22] R M Silverstein and G C Bassler Spectrometric IdentificationofOrganic Compounds JohnWileyamp SonsNewYorkNYUSA2nd edition 1967
[23] Y-G Zhao H-Y Shen S-D Pan and M-Q Hu ldquoSyn-thesis characterization and properties of ethylenediamine-functionalized Fe
3O4magnetic polymers for removal of Cr(VI)
in wastewaterrdquo Journal of Hazardous Materials vol 182 no 1-3pp 295ndash302 2010
[24] Y R Sharma Elementary Organic Absorption Spectroscopy SChand amp Co Ltd New Delhi India 1980
[25] D Kivelson and R Neiman ldquoESR line shapes in glasses ofcopper complexesrdquoThe Journal of Chemical Physics vol 35 no1 pp 149ndash155 1961
[26] E Pretsch P Buhlmann and C Afflolter Structure Determi-nation of Organic Compounds Springer New York NY USA2000
[27] J L White Modern Magnetic Resonance Kluwer AcademicPress London UK 2006
[28] M M Patel M A Kapadia and J D Joshi ldquoThermal andcatalytic aspects of Ln(III) polymer-metal complexesrdquo PolymerInternational vol 58 no 7 pp 728ndash737 2009
[29] S Nanjundan C S J Selvamalar and R Jayakumar ldquoSynthesisand characterization of poly(3-acetyl-4-hydroxyphenyl acry-late) and its Cu(II) and Ni(II) complexesrdquo European PolymerJournal vol 40 no 10 pp 2313ndash2321 2004
[30] A V Nikolaev V A Logvinenco and L I Myachina ThermalAnalysis Academic Press New York NY USA 1969
[31] A Z El-Sonbati and M A Hefni ldquoPolymer complexes PartXXVImdashNovel mixed ligand poly-(5-vinyl salicylidene)-12-diaminobenzene complexesrdquo Polymer Degradation and Stabil-ity vol 43 no 1 pp 33ndash42 1994
[32] A S Aswar and N S Bhave ldquoThermal degradation studies ofsome new coordination polymersrdquo Polymer Degradation andStability vol 31 no 1 pp 115ndash124 1991
[33] T Ahamad V Kumar and N Nishat ldquoSynthesis characteri-zation and antimicrobial activity of transition metal chelatedthiourea-formaldehyde resinrdquo Polymer International vol 55no 12 pp 1398ndash1406 2006
[34] M M Patel M A Kapadia G P Patel and J D Joshi ldquoSynthe-sis characterization ion-exchange and antimicrobial study of
poly[(2-hydroxy-4-methoxybenzophenone) propylene] resinand its polychelates with lanthanides (III)rdquo Journal of AppliedPolymer Science vol 106 no 2 pp 1307ndash1317 2007
[35] M A Neelakantan S S Marriappan J Dharmaraja T Jeyaku-mar and K Muthukumaran ldquoSpectral XRD SEM and bio-logical activities of transition metal complexes of polydentateligands containing thiazole moietyrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 71 no 2 pp 628ndash635 2008
[36] G B Bagihalli S A Patil and P S Badami ldquoSynthesisphysicochemical investigation and biological studies of zinc(II)complexes with 124-triazole schiff basesrdquo Journal of the IranianChemical Society vol 6 no 2 pp 259ndash270 2009
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Inorganic ChemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Carbohydrate Chemistry
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Spectroscopy
Analytical ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Organic Chemistry International
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Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Inorganic ChemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Carbohydrate Chemistry
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
Physical Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom
Analytical Methods in Chemistry
Journal of
Volume 2014
Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
SpectroscopyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Medicinal ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chromatography Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Applied ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Theoretical ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Spectroscopy
Analytical ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Quantum Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Organic Chemistry International
ElectrochemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CatalystsJournal of