Volume III, Issue III, March 2016 IJRSI ISSN 2321 - 2705 Synthesis … · 2016. 3. 15. · Volume...

Volume III, Issue III, March 2016 IJRSI ISSN 2321 - 2705

www.rsisinternational.org

Synthesis and Characterisation of Dinuclear Iron(III)

Complexes of the Schiff Base Ligands

G. Ananthakrishnan *, S. Sujatha K. Balasubramanian

Department of Physics, Saranathan College of Engineering, Trichirapalli-620 012, India

Abstract: - Dinuclear metal complexes prepared form Schiff base

having ON-NO donor atoms investigated into the magnetic

properties of molecular-based materials containing a polynuclear

assembly have become a fascinating subject in the field of

condensed matter physics and materials chemistry (Dalai et al.,

2002; Bhaduri et al., 2003. Also, the binuclear Fe (III) complex

have distorted octahedral configurations and was prepared

through the thermal transformation of its mononuclear complex

to the binuclear one. All complexes and the corresponding

thermal products were isolated and their structures were

elucidated by elemental analyses, conductance, IR and electronic

absorption spectra, magnetic moments, 1H NMR and EPR.

I. INTRODUCTION

he study of reactivity of organic molecules mixed to

nuclear transition-metal (e.g.di-iron) complexes has

received a great deal of attention during the past few years.

With the possibility of donating from two to eight electrons, via the

N-lone pairs, the C=N, π-electrons, conjugated diimine

ligands are known to behave a very versatile coordination

property to the bonded metal centre1. The synthesis of

polymeric complexes in this chapter using double bidentate

ligands has aroused much interest recently2-6

. Dinuclear metal

complexes prepared form Schiff base having ON-NO donor

atoms7-9

investigated into the magnetic properties of

molecular-based materials containing a polynuclear assembly

have become a fascinating subject in the field of condensed

matter physics and materials chemistry (Dalai et al., 2002;

Bhaduri et al., 2003). Polynuclear metal complexes have been

widely studied because of their interesting magnetic properties

such as long-range magnetic ordering and special category of

molecule –based materials –single molecule magnets7 -11

.

II. EXPERIMENTAL

Preparation of Schiff base ligands

A. Synthesis of 4,4-bis-[3,5-di-tert-butyl-(2-

iminomethylphenol)] dibenzanilide. (DDBA)(L1)

To an ethanol solution (30mL) of the 3,5-di-t-butyl-2-

hydroxybenzaldehyde (0.344g, 2mmol) was added with 4,4-

diaminobenzanilide (0.23g, 1.0mmol) in 20mL of ethanol.

The solution was stirred for 30 minutes and gently refluxed

for 8 hours when a deep yellow product began to deposit. The

solvent ethanol was evaporated under rotary evaporator and

the resulting shining dark yellow solid was recrystallised with

ethanol. The reaction mixture was cooled to room

temperature, filtered, washed with a minimum volume of

dichloromethane and dried in vacuum P4O10. The remaining

ligands were prepared in the same as above. The preparation

of this ligand is explained in the Scheme 4.1.

Yield-70%

Molecular formula: C43H53N3O3 (659.92), M.pt = 210-213C

1HNMR(CdCl3): δ(phenolic OH) 13.0 (s, 2H); 9.5-9.8 (s, 1H, NH),

8.3-8.6 (s, 2H, CH=N); 7.1 (d, 2H); 7.2 (d, 2H); 7.9-7.2 (m,

8H); 1.3-1.4 (s, 36H) (t-butyl).

B. Synthesis of 4,4-bis-[(2-iminomethylphenol)]

diphenylmethane (IDPM)(L2)

Yield-72%

Molecular formula: C27H22N2O2 (406.48) M.pt = 180-183C

1HNMR(CdCl3): δ (phenolic OH) 13.1 (s, 2H); 8.9-9.0 (s, 2H,

CH=N); 7.2-7.4 (m, 4H); 7.0 (d, 2H); 6.95 (d,2H); 7.21-7.4

(m, 8H); 4.2 (s, 2H).

C. Synthesis of 4,4-bis-[(2-iminomethylphenol)]

oxydibenzene(IODB) (L3)

Yield-73%

Molecular formula: C26H20N2O3 (408.45), M.pt = 185-187◦C

1HNMR(CdCl3): δ (phenolic OH); 13.2 (s, 2H); 8.3-8.6 (s, 2H,

CH=N); 7.42-7.36 (m, 4H); 7.03 (d, 2H); 6.95 (d, 2H); 7.31-

7.09 (m, 8H). The NMR spectrum is shown in Fig. 4.1.

D. Synthesis of 4,4-bis-[(2-iminomethylphenol)]

dibenzanilide(IDBA)(L4)

Yield-76%


1HNMR(CdCl3): δ (phenolic OH); 13.2 (s, 2H); 10.5 (S, 1H); 9.0

(s, 2H, CH=N) 7.61 (d, 2H); 7.5 (d, 2H); 7.4 (d, 2H); 6.7 (d,

2H); 7.5-8.1 (m,8H).

E. Synthesis of 4,4-bis-[3-hydroxy-(2-iminomethylphenol)]

diphenymethane (HDPM) (L5)

T



Yield-77%

Molecular formula: C27H22N2O4 (438.47), M.pt = 206-208◦C

1HNMR(CdCl3): δ (phenolic OH); 13.3-12.5 (s, 4H); 9.2 (s, 2H,

(CH=N); 6.83 (d, 2H); 7.0 (d, 2H); 7.2 (d, 2H); 7.4 -7.6 (m, 8H);

4.1 (s, 2H).

F. Synthesis of 4,4-bis-[3-hydroxy-(2-iminomethylphenol)]

oxydibenzene (HODB) (L6)

Yield-74%


1HNMR(CdCl3): δ (phenolic OH); 13.45-12.1 (s, 4H); 8.96 (s,

2H, CH=N); 7.08 (d, 2H); 6.8 (d, 2H); 6.6 (d, 2H); 7.2-7.5 (m,

8H).

G. Synthesis of 4,4-bis-[3-hydroxy-(2-iminomethylphenol)] dibenzanilide (HDBA) (L7)

Yield-82%

Molecular formula: C27H21N3O5 (467.47), M.pt=205-207◦C

1HNMR(CdCl3): δ (phenolic OH); 13.5-12.9 (s, 4H); 10.5 (S,

1H); 9.02 (s, 2H CH=N); 6.83 (d, 2H); 7.2 (d, 2H); 7.5 (d,

2H); 7.6-7.9 (m, 8H).

III. SYNTHESIS OF THE COMPLEXES

[Fe2(L1)2(Cl2)(H2O)2] To an DMF solution (20mL)

of the ligand (L1) (0.66g, 1mmol) was added triethylammine

(280µmL, 2.0mmol) in 5ml of DMF followed by the addition

of FeCl3. 6H2O (0.27g/1mmol) dissolved in (20ml) of DMF.

After 20 minutes of stirring, the solution was filtered. The

filtrate was kept at room temperature for overnight period,

during which time the red solid was obtained. A deep red

solid like product was filtered off and recrystallised from

dichloromethane. The remaining complexes were prepared in

the same as above. The complex synthesised is exhibited in

Scheme 4.2.

[Fe2(L1)2(Cl2)(H2O)2] ESI-MS: 1534.39 [Fe(L1)]2.,

FT-IR (KBr, /cm-1

): 3430, 2985, 1598, 1402, 1280, 1355,

1180, 1029, 972, 836, 638, 526, 415. Yield-75%.

[Fe2(L2)2(Cl2)(H2O)2] ESI-MS: 1027.55 [FT-IR

(KBr, /cm-1

): 3416, 2937, 1613, 1469, 1349, 1254, 1171,

1032, 841, 683, 576, 463. Yield-80%.

[Fe2(L3)2(Cl2)(H2O)2] ESI-MS: 1031.49 [Fe(L11)]2., FT-

IR (KBr, /cm-1

): 3354, 2956, 1580, 1472, 1345, 1238, 1114,

1088, 926, 842, 548. Yield-85%.


FT-IR (KBr, /cm-1

): 3423, 2985, 1637, 1599, 1342, 1280,

1180, 1029, 972, 908, 836, 638, 530, 456. Yield-83%


FT-IR (KBr, /cm-1

): 3428, 2999, 1340, 1031, 982, 840, 751,

637, 550, 446. Yield-72%.


FT-IR (KBr, /cm-1

): 3376, 2950, 1622, 1382, 1472, 1389,

1252, 1171, 1034, 842, 805, 747, 578, 485. Yield-69%.


FT-IR (KBr, /cm-1

): 3363, 2958, 1389, 1315, 1263, 1246,

1207, 1190, 845, 752, 544, 470.

Yield-77%.

IV. ANALYSIS AND PHYSIOCHEMICAL STUDIES OF

THE COMPLEXES

All the seven complexes were analysed for the metal

percentage. The anions present in the complexes were also

estimated. The molar conductivities of the complexes in DMF

(~10-3

M solutions) were measured at room temperature (28 ±

2C). Elemental analysis was performed on a Perkin Elmer

series II CHN ANALYSER 2400. Electronic spectra of

complexes were recorded using Lambda 35 UV-Vis

spectrophotometer. IR spectra were recorded on FT-IR

spectrophotometer using KBR pellets. EPR spectra of

powdered samples were measured at room temperature on a

JEOL JES-TE100 EPR spectrometer operating at X-band

frequencies, and having a 100 kHz phase modulation to obtain

the first derivative EPR spectrum. DPPH with g value of

2.0036 was used as an internal field marker. Cyclic

voltammograms were recorded on a Model POSG.125,

Central Electro Chemical Research Institute, Karaikudi. Mass

spectra were performed on a Thermo Finigan LCQ 6000

Advantage Max and Q-TOF ESI-MS instrument. Magnetic

susceptibility of the complexes was measured with the help of

SQUID and Vibrating sample magnetometer in the range of -

20000 and +20000 Gauss.

V. RESULTS AND DISCUSSION

A total of seven complexes have been isolated, all of

which are highly insoluble posses high melting point. They

are highly insoluble in common organic solvents like

methanol, acetonitrile, nitrobenzene but soluble in DMF and

DMSO. Analytical data for the ligands and complexes are

presented in (Tables1& 2). Important IR and electronic

spectral bands of the ligands and the complexes with their

tentative assignments are given in (Tables 3&4). Mass spectral data

for all the complexes are given in (Table.5). Cyclic voltammetry

of the complexes are presented in (Table.6). For all the

complexes, EPR and magnetic moment character are well

studied.

Elemental Analysis

The molecular weight of the ligands and the metal

complexes are presented in Tables 1&2



IR Spectroscopy

The infrared spectra of the azo-linked Schiff base

ligands displayed a shoulder of a broad band of weak intensity

around 2900-2911cm-1

. This band was ascribed to the shift to

significantly lower frequencies because of OH-N

intramolecular hydrogen bonding12-13

. The vibration of the

C=N in the complexes is displaced towards lower energies in

comparison with free ligand (Fig.1) (29cm-1

-10cm-1

) for all

complexes. The C-O phenolic is displaced to higher energies

(25 cm-1

) in all complexes. The spectra of the seven

complexes show a broad band at 3400 cm-1

due to water

molecules. The single absorption at 1383 cm-1

is indicative of

the ionic chloride group. On the other hand in the infrared

spectra of the complexes, new absorption bands at 505-

511cm-1

and 445-495cm-1

were observed indicating the M-N and

M-O bonds, respectively14-15

The bands present at 290-310 cm–1

may be assigned to ν(M–Cl) vibrations16-17

.

UV.Visible Spectroscopy

The UV- Vis spectrum (>200 nm) of ligands in DMF

consist of a band at 403.9 nm in ligand, refer to

n→π*excitation of the azomethine group and the bands

appears in 225-316 nm respectively in (Fig.2) which are

assigned as π→π* type transitions involving molecular

orbitals located on the phenolic chromophore, shift to a lower

wavelength in the complexes. This blue shift in the complexes

may be due to the donation of a lone pair of electrons by the

oxygen of the phenoxy group to the central metal atom. These

results show the imine group nitrogen atom has been

coordinated to the metal ion. The band at 233nm in complexes

refer to LMCT (πCl→dFe)18,19-21

.

The complexes exhibits the LMCT at energies higher

than the other complexes because the presence of electron

releasing group which enhances the electron density on

iron(III) destabilizing the d π* orbitals leading to an increase

in energy gap between the ligand and the metal orbitals and

hence the increase in energy of the observed LMCT bands.22

The less intense band observed in the range of 313-650 nm are

assigned respectively to phenolate (pπ)-Fe(III)(d∂*) and

phenolate (pπ)→Fe(III)(dπ*) ligand to metal charge transfer

(LMCT) transition23

. The important IR and UV spectral data

are presented in Tables 3&4 and shown in Fig.2.

EPR Spectroscopy

The X-band EPR spectra observed for all the

complexes in aqueous DMF exhibit an intense peak at g~4.3-

4.5 in the region of 1,500 gauss, typical of high spin (s = 5/2,

d5) iron(III) complexes (Fig.3) with low symmetry, as well as

commonly found in a variety of solid state materials, chelates

and metalloproteins24-25

.

Magnetic Moment Measurement

The magnetic moment values of all the complexes at

room temperature were found to be respectively, in

conformity with distorted octahedral high spin (s = 5/2, d5)

26

configuration for the complexes. For all the complexes

according to the curie Weiss fit: 1/χ vs T, where effective

moment value is 10.81 μB-11.15 μB (for 2 Fe ions)12

and 5.41-

5.57μB per Fe3+

ions is in high Spin state (3d5)

27 shown in Fig.

4.. These values are close to the theoretical value of 10.95 for

an spin state arising from two ferromagnetically coupled s =

5/2 with g = 2. These compounds are rare example of di-iron

clusters displaying ferromagnetic interactions28

. Since Fe3+

ion

in high spin state, M vs H plot shows ferromagnetic behaviour

at 5 K -300k in Figs.4.&4(a)&(b).

ESI-MS Studies

The ESI-MS of all the ligands and the complexes

showing a prominent peak corresponding to L4(435.48)

depicted in(Fig. 5). The ESI-MS of all the complexes showing

a prominent peak corresponding to a mononuclear ion peak

with high intensity in the range of 85-90% and the binuclear

ion with low intensity in the range of 5-10% presented in

Table.5 and its corresponding ESI-MS of the C86H102N6

O6.Fe2Cl2.(2H2O) complexes are depicted in (Fig. 5(a)).

Conductance Measurement

The electrical conductance of the complexes

Fe2(L1)2.Cl2, Fe2(L2)2.Cl2, Fe2(L3)2.Cl2, Fe2(L4)2.Cl2, Fe2(L5)2.Cl2,

Fe2(L6)2.Cl2 and Fe2(L7)2.Cl2 were 142.1, 140.5, 136.7, 168.5,

164.5, 166.8, 105.8, 135.7, 131.9 ohm-1

cm2 mol

-1 suggesting

1:2 electrolytic nature of the complexes29

.

Cylic Voltammetry

The electrochemical behaviour of complexes (C1-C7)

was carried out by employing CV and differential pulse

voltammetry (DPV) using a stationery Platinum sphere as

working electrode and non-aqueous Ag/Ag+ electrode as

reference electrode. A single process is observed for (C1-C7)

complexes in acetonitrile, being attributed to the redox couple

Fe(III)/Fe(II). The redox couple is electrochemically quasi

reversible (ΔEp > 100mV) in (Fig.6 & Table 6) where both

reduction and oxidation takes place. The free ligands did not

show any response, where the complexes indicates (ΔEp > 100

mV) corresponding to (FeIII

/FeII) couple with half –wave

potential (E1/2), being negative. In the mononuclear iron(III)

complexes undergoing a one –electron reduction30-31

and for

dinuclear iron(III) complexes32

exhibiting a two –electron

reduction process. Interesting the E1/2 values of FeIII/II redox

values of the dimeric complexes (C3) are observed at potential

more negative than the mononuclear complexes. This is an

interesting as incorporation of the electron releasing tert-butyl

groups (C3)as in the former would be expected to decrease

the Lewis acidity of the ferric centre and hence shifts to more

negative potential values33

.

The presence of the electron withdrawing would be

expected to increase the Lewis acidity of the ferric centre and

hence shifts to less negative potential values as compared to

the complexes (C5), (C6) & (C7). So these observation reveals



that the bulky t-butyl group adjacent to the phenolate

donor sterically hinders it form a strong bond with iron(III).

The Kcon value 1.822 106

– 3.452 102

obtained

for the complexes respectively. These values are consistent

with moderate coupling and charge delocalization between the

metal centres.

VI. SUMMARY

The geometry of the complexes is found to be

distorted octahedral geometry and was confirmed by

elemental analysis, UV, EPR, conductance measurements

Aquated di-iron(III)-Schiff base complexes of the type

[Fe(Ln) (H2O)2Cl2] have been synthesized from the reaction

of [N2O2] donor tetradentate Schiff bases (L1-L7) with

FeCl3.6H2O and characterized by spectroscopic methods.

EPR, Magnetic measurements and conductivity

studies support a high spin (d5) 1:2 electrolytic nature of the

complexes. The complexes reveal quasi-reversible redox

behavior with peak separation, ΔEp > 100 mV. These

compounds are rare example of di-iron clusters displaying

ferromagnetic interactions. These values are close to the

theoretical value of 10.95 for a spin state arising from two

ferromagnetically coupled s = 5/2 with g = 2. These

compounds are rare examples of di-iron clusters displaying

ferromagnetic interactions. Since Fe3+

ion is in high spin state,

M vs H plot shows ferromagnetic behaviour at 5K-300K.

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3437.



CHO

OH +

NH2

Stirred 30 minutes

Refluxed 8 hours

HO

N

H

H2N

OH

N

H

Ligand R1 R2

(R3)

R3

(L7)

(L8)

(L9)

(L10)

(L11)

(L12)

(L13)

(L14)

(L15)

t-butyl

t-butyl

t-butyl

H

H

H

OH

OH

OH

H

H

H

t-butyl

t-butyl

t-butyl

H

H

H

4'4-diaminodiphenylmethane

4'4-oxydianiline

4'4-diaminobenzanilide


4'4-oxydianiline



4'4-oxydianiline


H

H

Salicylaldehyde4'4-diaminodiphenylmethane

(R2)

(R1)

H

H H

H

(L10)

Scheme – I



H2O Fe Cl

O

Cl Fe OH2

H

N

O

N

H H

N

O

H

N

O

H

H H

H

H

H H

H

(C10)

HO

N

H

OH

N

H

H

H H

H

(L10)

+ FeCl36H2O

Stirred for 30 minutes

Refluxed for 4 hours

Scheme – II



Fig.1: Infrared Spectrum of Complex Fe(L13)Cl2.2H2O



Fig.2: UV-Vis absorption spectra of Complex for Fe2(L10)Cl2.2H2O and d-d transistion of Fe2(L15)Cl2.2H2O in the solvent of DMF at 298K



Fig. 3: g values of the X-band EPR spectra for Fe2(L3)2 at temperature 6 K, microwave frequency 9.338 GHz, modulation 1G .



0 50 100 150 200 250 300 350

0

10

20

30

40

50

60

70

1/

O

e-m

ole

/em

u

Temperature (K)

Fig 4.: The Curie-Weiss plot shows the inverse of magnetic susceptibility as a function of temperature for complex Fe(L7). The solid line resulted from a least-squares fit of the data



-8 -6 -4 -2 0 2 4 6 8-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

H (T)

M (

B/ m

ole

cule

)

MuB/molecule

C-15

T = 5 K

Fig. 4.(a): The plot shows M vs H at 5K for the complex [Fe(L7)]+



-8 -6 -4 -2 0 2 4 6 8-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

H (T)

M (

B/

mo

lecu

le)

MuB/molecule C-15

T = 300 K

Fig. 4.(b): The plot shows M vs H at 300K for the complex [Fe(L7)]+



Fig. 5: Electrospray mass spectrum of the ligand (L4)



Fig. 5(a): Electrospray mass spectrum of C86H102N6 O6.Fe2Cl2.(2H2O)



Fig.6: Cyclic voltammogram of Fe2(L5)2Cl2.2H2O of 1mmol.dm-3 in DMF solvent at a scan rate of 100mv/sec measured in 100mmol.dm-3 TBAPF6/CH3CN on a glassy carbon electrode at 25C



Table 1

Elemental analysis of the Schiff base ligands

Ligand Molecular

formula Colour

Formula

weight Yield %

Found (calculated)%

C H N O

(L1) C43H53N3O3 Light yellow powder 659.92 85 76.38

(77.50)

8.09

(8.05)

6.36

(6.56)

7.27

(7.57)

(L2) C27H22N2O2 Yellow crystalline powder 406.48 70 79.63

(79.60)

5.45

(5.60)

6.88

(6.98)

7.87

(7.97)

(L3) C26H20N2O3 Light Yellow 408.45 85 78.19

(77.19)

4.93

(5.03)

6.85

(7.25)

11.75

(11.70)

(L4) C27H21N3O3 Yellow solid 435.48 75 74.40

(73.50)

4.86

(4.96)

9.64

(9.78)

11.02

(11.23)

(L5) C27H22N2O4 Dark Orange solid 438.47 80 73.89

(74.58)

5.05

(5.95)

6.38

(6.95)

14.59

(14.35)

(L6) C26H20N2O5 Dark Orange solid 440.44 75 70.83

(71.25)

4.57

(4.87)

6.35

(5.53)

18.16

(17.96)

(L7) C27H21N3O5 Dark orange solid 467.46 85 69.30

(68.95)

4.52

(4.92)

8.98

(9.58)

17.11

(16.58)

Table 2

Elemental analysis of the dinuclear iron(III) complexes

Complex Molecular formula Colour

Formula

weight

Yield

%

(calculated)%Found

C H N O Fe Cl

(C1) C86H102N6 O6.Fe2Cl2. (2H2O) Dark Green 1534.39 55 67.32

66.58

6.96

7.58

5.48

5.26

8.34

8.54

7.38

7.46

4.62

4.55

(C2) C54H40N4O4 Fe2Cl2. (2H2O) Reddish Brown solid 1027.55 56 63.12

62.95

4.32

4.05

5.45

5.98

9.34

1.058

10.87

11.56

6.90

7.80


61.05

3.91

3.97

5.43

5.68

12.41

12.96

10.83

11.25

6.87

6.98


58.95

3.9

3.97

7.74

8.25

11.79

12.56

10.29

09.85

6.53

5.89

(C5) C54H44N4O8.Fe2Cl2. (2H2O) Black solid 1091.54 65 59.42

58.39

4.06

3.78

5.13

5.65

14.66

13.98

10.23

09.78

6.50

5.98

(C6) C52H40N4O10.Fe2Cl2. (2H2O) Black solid 1095.49 45 57.01

56.95

3.68

3.25

5.11

4.95

17.53

16.95

10.20

9.89

6.47

6.05

(C7) C54H42N6O10.Fe2Cl2. (2H2O) Black solid 1149.54 65 56.42 55.95

3.68 3.95

7.31 6.98

16.70 15.98

9.72 9.56

6.17 6.35



Table 3

UV and IR spectral data of Schiff base ligands

Ligand UV DATA(nm)

IR spectral data (cm-1)

-OH (C=N) (C-O)

(L1) 255, 325, 351 3459 1601 1325

(L2) 230, 304, 356 3466 1629 1329

(L3) 270, 345, 355 3459 1638 1320

(L4) 260, 293, 375 3526 1650 1322

(L5) 265, 290, 368 3450 1637 1319

(L6) 254, 323, 325 3455 1620 1352

(L7) 261, 308, 356 3464 1646 1369

Table 4

UV and IR spectral data of the dinuclear iron(III) complexes

Complex UV DATA(nm)

IR spectral data (cm-1

2H Oν CH=N C-O M-N M-O

(C1) 251, 381, 387, 630 3430 1598 1355 526 415

(C2) 198, 240, 313, 360, 631 3416 1613 1349 576 463

(C3) 243(sh), 383(sh), 649 3354 1623 1345 548 ------

(C4) 233(sh), 423, 641 3423 1627 1342 530 456

(C5) 232(sh), 480, 650 3428 1637 1340 550 446

(C6) 241, 453, 650 3376 1622 1382 578 485

(C7) 237, 424, 670 3363 1646 1389 544 470



Table 5

ESI –MS Analysis of the complexes

Complex Structural Elucidation E/S mz

(C1) C43H51N3O3FeCl.H2O

C86H102N6 O6Fe2Cl2.2H2O

767.19

1534(M+H+)


C54H40N4O4 Fe2Cl2.2H2O

513.77

1027(M+H+)


C52H36N4O6 Fe2.Cl2.2H2O 515.74

1031(M+H+)


C54H38N6O6 Fe2.Cl2.2H2O

542.77

1085(M+H+)


C54H44N4O8 Fe2.Cl2.2H2O 545.77

1091(M+H+)


C52H40 N4O10Fe2Cl2.2H2O

547.74

1095(M+H+)


C54H42N6O10Fe2Cl2.2H2O

574.77

1149(M+H+)

Table 6

Cyclic Voltammetry for the dinuclear iron(III) complexes

Complex Epa(v) Epc(v) ΔEp(V) E1/2(V)b Kcon

(C1) -1.03

-1.25

-0.85

-1.18

-0.18

-0.07

-0.94

-1.21 3.702 104

(C2) -0.51

-0.67

-0.41

-0.55

-0.10

-0.12

-0.46

-0.61 3.452 102

(C3) -0.45

-0.77

-0.34

-0.62

-0.11

-0.15

-0.40

-0.70 1.191 105

(C4) -0.50

-0.72

-0.32

-0.56

-0.18

-0.16

-0.41

-0.64 7.793 103

(C5) -0.52

-0.85

-0.58

-0.75

-0.06

-0.10

-0.55

-0.80 1.698 104

(C6) -0.64

-0.92

-0.52

-0.76

-0.12

-0.16

-0.58

-0.84 2.507 104

(C7) -0.48

-0.81

-0.36

-0.72

-0.12

-0.09

-0.42

-0.76 8.359 105

Volume III, Issue III, March 2016 IJRSI ISSN 2321 - 2705 Synthesis … · 2016. 3. 15. · Volume...

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Transcript of Volume III, Issue III, March 2016 IJRSI ISSN 2321 - 2705 Synthesis … · 2016. 3. 15. · Volume...