CHAPTER-6

FTIR AND FTR ASSIGNMENTS ANDVIBRATIONAL ANALYSIS OF

2-AMINO PYRIDINE AND 2-AMINOlOLINE

FTIR AND FTR ASSIGNMENTS AND VIBRATIONAL

ANALYSIS OF 2-AMINO PYRIDINE AND 2-AMINO PICOLINE

1. INTRODUCTION

Pyridine, also called azabenzene or azine is the most benzene like of the heterocyclic

compounds. It has a high resonance energy and its structure resembles to benzene

quite closely. The presence of nitrogen atom in the ring does, of course, represent a

major perturbation and alkylation which has no analogy in benzene. When we

encounter with the properties of pyridine, they resembles to those of tertiary amine

and the aromatic sextet is not involved in these reaction. Distortion of electron

distribution in both it-bonding system and in the ci- bonding system are due to the

influence of nitrogen atom. Nucleophilic substitution not common in benzene is

much easier in pyridines, particularly at the 2- and 4- positions which are activated

by nitrogen. Aminopyridines are obtained from pyridine by replacing the hydrogen

attached to the ring by an amino group. By an appropriate location of the amine in

the pyridine ring either 2- or 3- or 4-aminopyridine shortened by 2AP, 3AP and 4AP

can be obtained.

Heterocyclic àmines (HAs) serve as potent food mutagens, formed in fried, broiled

or grilled meats and increase rates of colon, mammary, prostate and other cancers in

bioassay rodents. Studies of human dietary HA exposure was done to US National

Continuing Survey of Food Intakes by Individual (CSFII) data on meats consumed

and cooking methods showed that the pan-fried meats were the largest source of

115

HAs in the diet and chicken, the largest source of HAs among different meat types

[1]. The heterocyclic amine(HCA), 2-amino-i -methyl-6-phenylimidazo-[4,5-b]-

pyridine (PhIP) forms high levels of adducts in a number of organs particularly

liver, kidney and heart and causes HCA induced carcinogenesis [2]. The exogenous

compounds such as PhIP (HA) may have an important role in the generation of

tumours in Mismatch Repair (MMR) defective individuals. The datas suggest that

PhIP may increase the risk of human carcinogenesis and there by promote

tumourigenesis by mutating growth regulating genes [3]. As a part of a

comprehensive survey of the heterocyclic amine content of foods, hamburgers,

steaks and pork ribs were purchased from restaurants and the results revealed that

the restaurant products are ten fold higher in heterocyclic amine content [4].

Aminopyridines find wide application in pharmacological industry and in analytical

chemical laboratories. They serve as good anesthetic agent and hence used in the

preparation of drugs for certain brain disease particulary 4-Aminopyridine is an

effective medicine in the treatment for Multiple Sclerosis [5].

Aminopyridines are used as anti-convulsants and sodium channel blockers. The

pharmaceutically acceptable salts and pro drugs are used for the treatment of

neuronal damage following global and focal ischemia, for the treatment or

prevention of neuro degenerative conditions such as Amyotrophic Lateral Sclerosis

(ALS) and for the treatment, prevention or amelioration of both acute or chronic

pain, as anti-tinnitus agents, as anti-manic depressants, as local anesthetics as anti

116

arrhythmics and for the treatment or prevention of diabetic neuropathy [6].

The compounds comprising supramolecular complexes of amino pyridine e.g

Melamine is used in Engineering plastics for high temperature applications since

they have little bubble formation during processing [7]. Memantine and Flupirtine-

the derivatives of aminopyridine are extensively used in pharmacology. The

N-methyl-D-aspartate (NMDA) antagonist Memantine - a drug currently used in the

therapy of spasticity and Parkinson's disease. Flupirtine was found to be centrally

acting, non-opiate analgesic agent which additionally possesses anticonvulsant and

muscle-relaxant activity. Also these drugs almost have no clinical side effects, these

may prove useful both in preventing primary infection of brain cells with the HIV-

virus as well as treating the neurological disorders often associated with the immuno

deficiency syndrome such as AIDS related dementia [8].

The non planarity of aminogroup in aminopyridines were investigated by ab initio

methods and the amino group was found to be non-planar in all the systems [9]. As

4-amino pyridine improves the transmission of nerve impulses down damaged

axons, it drastically improves the conditions of patients suffering from spinal-cord

injury [10]. The 3,4-diaminopyridine plays an effective role in the symptomatic

treatment of multiple sclerosis fatigue like 4-aminopyridine [ 11 ] . Even though

4-Aminopyridine is highly toxic to all mammals including humans if dosages are

exceeded agriculturally, it is used as an extremely effective bird poison sold under

the brand name Avitrol [12].

117

3-aminopyridine is used as intermediate for agro chemical pharmaceuticals mainly

Piroxicam, Tenoxicam, Ampiroxicam and dyes [13]. The pink colour defect in

cooked, uncured turkey is a sporadic problem that can result in economic loss and

consumer dissatisfaction. Fourteen ligands were tested in ground turkey samples for

their ability to reduce pink development and 3AP was one of them [14].

2- amino pyridine can be used as intermediate for the synthesis of pharmaceuticals

especially for antihistamines, anti-inflammatory and other drugs [15]. 2AP is used

in the synthesis of biologically useful synthon 2-chloro-5-hydroxy pyridine- a key

component of the non-opioid analgesic agent [16]. Of several weakly basic

compounds tested, 2- Aminopyridine was selected as the most useful UV-active

substance [17]. 2- Amino pyridine and its pharmaceutically acceptable salts are of

useful in disease like septic shock, rheumatism, allergy, parkinsonism,

cardiovascular diseases, obesity and pain [18]. In high performance liquid

chromatography, 2-amino pyridine is used as a fluorometric label [19]. 2AP is used

in the synthesis of 1,3,1 0-triaryl-imidazolo [4,5-e] pyrido [1,2-a] -2,3,4,1 0-tetra

hydopyrimidine-2-thiones which display notable herbicidal activity [20].

Another derivative of interest in this context is 2-amino-4-methyl pyridine or

4-picoline also known as Amino picoline. It is the new radio ligand and was

developed to measure the binding of molecule to the Nos isoenzymes. Various

nitric oxide synthase (Nos) inhibitors were investigated for their affinity and

118

selectivity towards the three human Nos isoenzymes in radio ligand binding

experiments. 2-amino-4-methyl pyridine bound saturably and with high affinity to

human Nos. The datas identified 2-Amino-4-Picoline as a very useful radio label

for the investigation of the substrate binding site of all three isoforms [21]. Two

new one dimensional oxalato-bridged copper (II) complexes with 2-amino-4-methyl

pyridine and 3-hydroxypyridine were synthesized and characterized by FTIR

spectroscopy [22]. 2-amino picoline serves as an effective reagent in chemical

laboratories. In the chelation-assisted hydroacylation of allylic alcohols 2-amino-4-

picoline is used [23].

Derivatives of picoline have potent hypolipidemic effects, antineoplastic and anti-

inflammatory activities in rodents. Some of the derivatives demonstrated more

potent antineospalastic activity against the Ehrlich ascites carcinoma growth

including 2-amino-4-methyl pyridine cyanoborane and 2-amino-pyridine-

cyanoborane. Most of the derivatives showed good activity against murineL1210

lymphoid leukemia, Tmolt3 human leukemia, Uterine HeLaS cells and human

glioma cell growth [24].

A series of 2-amino-5-substituted pyridine derivatives are toxic and exhibit high

molluscidal activity. The most effective compounds were 2-amino-541-

(benzoliazole- 1 -ylmethyl)-3-methyl pyridine and 2-amino-5- [1 -(benzotriazole-

1-yl)nonyl]-3-methyl pyridine etc [25]. 2-aminopicoline is used along with max.

dose of bromide, chloride or perchlorate complex inorder to the protection towards

119

the human red blood cell damage photoinduced by chloroperbenzoic acid(CPBA)

[26] . 2-amino picoline and 2-amino pyridine have very important effects on the

corrosion of mild steel in HCL and these tend to inhibit the corrosion to a

remarkable extent. It was also found that 2-amino methyl pyridine exhibits higher

maximum efficiency than 2AP [27].

This molecule is also very important in medical and agricultural like applications.

When it is mixed with Rifamycin and iodine in CH202 at room temperature and

treated with 20% ascorbic acid gives 4-deoxy-4-methyl pyrido imidazo rifamycin.

This has outstanding antibacterial properties in vitio and in vivo and are very useful

in combating gastrointestinal micobial infections [28]. However its spectral

characteristics are still not fully explored and has been always a source of interest to

spectroscopists.

Gunasekeran et al. [29] carried out a Fourier transformation infrared and Laser

Raman spectroscopic investigation on 2N (benzoylamino) pyridine. They recorded

the FTIR spectrum in the range 4000 cm-1 - 400 cm4 and the Laser Raman spectrum

in the frequency range 4000 cm -1-100 cm'. They analyzed the spectra on the basis

of C symmetry and assigned the observed bands to different modes of vibration.

The assignments were made from the data collected on magnitude and relative

intensities of the observed bands. They compared assignments with the earlier

relevant works.

120

The study of vibrational spectra of substituted pyridines, aminopyridines attract the

attention of many spectroscopists because of their pharmaceutical and agrochemical

applications. Near infrared spectra of 2-, 3- and 4-aminopyridines and their

deuterated analogs were reported by Padhye and Bhujle [30]. They presented an

analysis of combination and overtone bands involving amino group frequencies.

Their spectral analysis shows that the overtones of the bands due to dimmers of

aminopyridine, clearly observed in the fundamental region, have not been observed

in near infrared region.

Baruah et al. [31] presented the Raman and infrared spectra of 2,6-diaminopyridine

in the region 250 cm'-lOOO cm'. Based on the assumption that 2,6-

diaminopyridine belongs to C 2 , point group symmetry, they proposed the

assignment for the prominent vibrational frequencies of the spectrum. Sanyal et al.

[32] presented the results on investigation on the electronic (3 120A°-2900A°) and

infrared absorption (400 cm'- 4000 cm') spectra of 3-amino-2-chloro pyridine. The

vibrational spectra have been analyzed in terms of fundamentals, the combinations

and overtones. They have assigned most of the prominent vibrational bands in the

spectrum. The IR and Raman spectra of mono crystals and polycrystalline samples

of 4-aminopyridine hemiperchiorate have been studied at various temperatures [33].

The far infrared vapour phase spectra of amino pyridine was presented and analyzed

by Kydd et al. [34]. They reported the spectra between 50- and 665 cm' and found

that the far-infrared vapour phase spectra of amino pyridine were dominated by lines

121

due to transitions in the inversion vibration energy levels of the amino group. The

barriers to inversion were determined by them and were shown to correlate

extremely well with the calculated electron density in the amino nitrogen but slightly

differ with the dihedral angle, between the rings and amino group planes.

The JR and Raman spectroscopic investigation of cadmium tetra cyanonickelate

complexes of amino pyridine was reported and was concluded that ring nitrogen and

not the amino nitrogen is involved in complex formation [35]. Kinie Sasaki et al.

[36] recorded and reported the infrared and Raman spectra for Iodine dichloride and

iodine dibromides of 2-, 3- and 4- aminopyridineim solids. Baran et al. [37] have

presented the polarized infrared spectra of 4-aminopyridine hemiperchiorate single

crystal containing structurally asymmetric NHN bridges at room temperature and

liquid nitrogen temperature. They particularly studied the nature of different modes

of vibrations of nitro group.

Carmona et al. [38] reported the vibrational studies on amino pyridines in aqueous

solution by Laser Raman Spectroscopy. They recorded the Raman spectra of 2-, 3-

and 4-aniinopyridine and 3,4-diaminopyridine in water over the frequency range

4000 cm'-300 cm'. They made the vibrational assignments for many of the

observed frequencies on the basis of isotopic frequency shifts, depolarization ratios,

group frequency consideration as well as comparison with accepted assignments for

certain vibrational modes in other compounds with structural similarities. The

assignments of the Raman spectra of mono amino pyridine was made on the

122

assumption that 2- and 3-amino pyridine belongs to planer Cs point group and the

4-amino pyridine possesses C2 symmetry.

After going through the literatures the need for a through vibrational analysis of

aminopyridines is felt, because the understanding of the force field that hold the

molecular structure of these compounds may provide a deeper insight into their

biological actions when they administered as drugs and in environment as

agrochemicals. Hence in the present investigation the FTIR and FT Raman spectra

of all the 2-, 3-, 4- aminopyridine and 3,4-diaminopyridine were recorded and an

assignment of the observed frequencies to the fundamental vibrational modes of the

molecules were made. A normal coordinate analysis of the said compounds was

also carried out since this could not only help the proper assignment of the

vibrational • frequencies but also present a complete picture about the molecular

dynamics of amino-pyridines.

2. EXPERIMENTAL DETAILS

The samples of the compounds 2-amino pyridine and 2-amino-4-methyl pyridine

were obtained from M/s Aldrich Chemicals U.S.A with stated purity 99% and used

as such without further purification to record FTIR and FTR spectra. The FFIR

spectrum of this compound has been recorded in solid phase following the KBr

pellet in the region between 4000 cm-1 - 400 cm' using Bruker IFS 66V spectrometer

with a scanning speed of 30 cm-1 rnin 1 of spectral width 2.0 cm'. The frequencies

for all sharp bands are accurate to ± 1 cm'. The FT Raman spectrum was also

123

recorded in the same instrument with FRA 106 Raman module equipped with

Nd:YAG laser source operating at 1.064 pm line with 200 mW power and the

spectral resolution is 2 cm 1 . The molecular structure of 2-aminopyridine and

2-amino picoline are shown in fig. 1 and fig. 2. The recorded FTIR and FT Raman

spectra of these compounds are shown in fig 3 and fig. 4 respectively.

3. NORMAL COORDINATE ANALYSIS

Section I

2-AMINO PYRIDINE

The compound, 2-amino pyridine under investigation posses C point group

symmetry by assuming (-NH 2) group as point mass and lies in the plane of the

molecule. C symmetry leads to two types of vibrations namely a' (in-plane) and a"

(out-of-plane) and are distributed into

F vib = 25a+ 8a"

All the vibrations are active both in JR and Raman. The normal co-ordinate analysis

program of Fuhrer et al. [39] was used after suitable modification to calculate

vibrational frequencies and potential energy distribution (PED). This program

follows the Wilson's FG matrix method [40-42] of vibrational analysis in which the

normal co-ordinates are defined with respect to a set of molecular co-ordinates.

JUPAC recommendations were also followed for defining the internal co-ordinates

for the out-of-plane bending vibrations. The structural parameters necessary for the

compound are taken from Sutton table [43] and from the literatures C-C = 1.401 A°,

124

NH2

Fig I. Molecular Structure of 2 - amino pyridine

0000CD000I-

00N00I-

00

CD•1>CL

0CE4

E U

-..

CD

crwD

L)

zLLJw

o--

I-LLz4I—ILr)(IL

000(.400N(.400(.400CD(.400co(.4000(V)

0(.4C',

00C,)

CDC!)

C-H = 1.103 A°, C-NH2 = 1.366 A°, N-H = 0.960 A° and all the ring angles are

1200 . These values are cross checked with molecular modeling program [44]. The

Simplified Valance Force Field (SVFF) was adopted and the force constants were

refined by the damped least square technique. The potential energy distributions are

calculated using the final set of force constants. The SVFF is shown to be very

effective in the normal co-ordinate analysis (NCA) because of the valance force

constants can be transferred between the structurally related molecules, benzene and

pyridine. A salient feature of NCA and force field calculations has been that it could

reproduce the frequencies associated with the skeletal rings as well as the -NH2

group within a reasonable limit (±10 cm') with an acceptable potential energy

distribution.

The potential energy distribution has been calculated in order to check whether the

chosen set of vibrational frequencies contributes the maximum to the potential

energy associated with normal co-ordinate of the molecules. The highest PED

contributions corresponding to each of the observed frequencies are alone listed in

the present work and the PEDs are also listed along with the frequencies in the table.

The close agreement between the observed and calculated frequency confirms the

validity of the present assignment.

4. VIBRATIONAL ASSIGNMENT

The initial and final set of force constants employed in the present investigation are

given in the table. l. and the observed and calculated frequencies of 2AP along with

125

their relative intensities and probable assignments are presented in table 2.

Assignments have been made on the basis of relative intensities, magnitude of the

frequencies and mainly on the normal co-ordinate calculations as well as literature

data of molecules of similar structure. The vibration of the molecule under study are

divided into two groups: (1) Skeletal vibrations i.e. the vibrations associated with the

ring and (2) Group vibrations due to the substituents. Apart from the assignments to

fundamental vibrations, attempt was also made to assign the overtone and

combination bands. The purity of the normal modes is further confirmed by

calculating the potential energy to each fundamental vibrations. The assignments

pertaining to overtones and combination bands of the samples were not discussed

but listed in the table 2.

4.1 SKELETAL VIBRATIONS

4.1.1 Carbon-carbon vibrations

The ring stretching vibration C-C are very much prominent in the spectrum of

pyridine and its derivatives and are highly characteristic of the aromatic ring itself

[45] . Benzene has two doubly degenerate mode e2g (1596 cm 1 ) and ei (1495 cm')

and two non-degenerate mode b2 (1310 cm-1 ) and aig (995 cm') due to skeletal

stretching of C-C bond. In general the bands around 1650 cm' to 1400 cm' in

benzene derivatives are assigned to skeletal C-C stretching modes [46] . The actual

position are determined not so much by the nature but by the position of the

substituents around the ring [47]. The bands observed at 1684 cm-' and 1617 cm1

in FTIR have been assigned to C=C stretching vibration of 2AP.

126

The bands at 1584 cm' and 1549 cm' in FTIR and 1584 cm -1 and 1545 cm-1 in FTR

have been assigned to C-C stretching vibrations in 2AP. The band at 1028 cm -1 both

in FTIR and FTR has been assigned to C-N stretching. Also C=N stretching

vibration bands are obtained at 1473 cm' in FTIR while 1470 cm-1 in FTR.

The C-C ring breathing aig (995 cm-1 ) and CCC triagonal bending non-degenerate

b1 (1010 cm-1 ) vibrations of benzene give rise to combined modified modes under

Cs symmetry in the present study. The characteristics absorption bands at 842 cm'

in FTIR and 840 cm-1 in FTR belong to ring breathing. These values are in

agreement with the ring breathing mode vibration at around 1000 cm 1 in substituted

benzene [48-49].

In the case of substituted benzene two more in-plane bending vibrations are obtained

from the non-degenerative b1 (1010 cm) and degenerate e2g (606 cm) mode of

benzene [47]. In this present case of 2AP, these are observed at 973 cm 1 and

942 cm' in FTIR and the Raman counterparts are identified at 970 cm 4 and 949 cm4.

The Carbon out-of-plane bending vibrations are derived from the non-degenerate

b2g (703 cm-) and degenerate e21,(404 cm -) modes of benzene. The former is found

constant in substituted benzene [50]. For 2AP this is shifted to 756 cm 1 in FTIR.

4.1.2 carbon-Hydrogen Vibrations

Because of the four C-H bonds in the structure, 2-amino pyridine gives rise to four

127

C-H stretching vibrations. The hetero-aromatic structure shows the presence of C-H

stretching vibration in the region 3000 cm'- 3100 cm' [46]. In this region the bands

are not affected appreciably by the nature of the substituents. In the present work,

the bands observed at 3066 cm', 3049 cm' and 3017 cm_ i in the infrared spectrum

and the corresponding Raman frequencies are observed at 3070 cm', 3053 cm-1 and

3028 cm-1 are assigned to the aromatic C-H stretching vibrations in 2AP. Studies on

the benzene spectrum show that there appear two degenerate e2g (1178 cm-1 ) and

(1037cm 1) and two non-degenerate b2 (1152 cm 1 ) and a2g (1340 cm-1 ) frequencies

involving C-H in-plane vibrations. C-H in-plane bending vibrations lie in the

region1000cm 1 - 1100 cm'. In the light of the above facts, the frequencies

1428 cm 1 , 1314 cm' and 1263 cm-1 in FTIR and 1442 cm', 1311 cm 1 and

1263 cm' in FIR are assigned to C-H in-plane bending vibrations.

The C-H out-of-plane deformation results from b2g (985 cm-') e2 (970 cm1),

eig (820 cm') and a2U(671 cm) modes of benzene and they are expected to occur in

the region 600 cm'- 1000 cm'. The changes in the frequencies of these

deformations from their values in benzene are almost determined exclusively by the

relative position of the sub stituents and are almost independent of their nature [451.

Hence the band 1170 cm - ', 1142 cm 1 , 1128 cm' and 1110 cm' in FTIR and have

almost same counterparts in FIR are assigned to C-H out-of-plane vibrations.

4.1.4 Carbon-Amine vibrations

Carmona et al. [38] assigned C-NH2 stretching absorption in the region 1250 cm1

and 1340 cm' in all the primary aromatic amines. The intensity of the bands

128

appears to be rather variable and probably it is associated with some substituents or

other structural features. Here in this present work, the medium strong bands at

1328 cm 1 in FTIR and in FTR are assigned to C-NH2 stretching vibrations. C-NH2

in-plane bending vibration is assigned at 428 cm 1 in FTIR and C-NH2 out-of-plane

vibration is assigned at 400 cm' in FTIR and 403 cm-1 in Raman.

4.2. GROUP VIBRATION

4.2.1 Amino group

Group vibrations were determined in terms of the motions of the nuclei undergo

during vibrations in the molecules and they appear in fairly constant region of the

spectrum. 2AP possess one NH 2 group and hence one expects one asymmetric and

one symmetric NH stretching in its spectra. It is stated that in amines, the N-H

stretching vibrations occur in the region 3500 cm'-3000 cm 1 [51]. The asymmetric

-NH2 stretching vibration appears from 3500 cm 1 - 3420 cm' and the symmetric

-NH2 stretching is observed in the range 3420 cm 1 to 3340 cm-1 . With reference to

this, the vibrational frequencies observed at 3442 cm -1 both in FTIR and FTR is

assigned to N-H asymmetric stretching vibration and the frequency observed at

3300 cm-1 both in FTIR and FTR is assigned to N-H symmetric stretching

vibrations. These observations agree well with the earlier work [52-531.

Other vibrations of amino group that is deformation has the characteristic frequency

usually located in the region 1650 cm-1 - 1600 cm-1 [47]. Therefore the medium

band in Raman at 1628 cm 1 is assigned to the deformation vibration mode of amino

129

group. Like wise the out-of-plane bending of amino group or wagging, the band

appears between 850 cm-1 and 750 cm-1 . Here the band at 617 cm' in infrared and

at 621cm' in Raman spectra is attributed to the amino wagging mode.

5. POTENTIAL ENERGY DISTRIBUTION

The Potential Energy Distribution (PED) has been calculated to check whether the

chosen set of assignments contribute the most to the potential energy associated with

normal co-ordinates of the molecules. The higher PEDs contribution corresponding

to each of the observed frequency is listed in the table 2.

From the normal coordinate analysis, the calculation of potential energy distribution

of the fundamental vibration modes show that almost all skeletal as well as group

vibration of the compound contribute maximum to the potential energy associated

with the respective bonds. Generally the skeletal carbon stretching vibrations

coupled slightly with the C-H stretching and CCC in-plane bending modes. The C-

H stretching, -NH2 stretching vibrations are considered to be absolutely pure modes

since the PED contribution of these modes are almost 100%. The C-H in-plane and

out-of-plane bending vibrations are also obtained in pure modes. From the NCA, it

is also observed that the maximum number of fundamental vibrations obtained

below 500 cm_ i significantly mixed with the neighboring modes. The RE

calculation determines the reliability and precision of the present spectral

assignments of the fundamental vibrational modes of the compound.

130

SECTION II

2-AMINO 4-METHYL PYRIDINE

2-amino-4-methyl pyridine also posses a C point group symmetry and the (-NH2)

group and (-CH3) group are considered as point masses and lie in the plane of the

molecule. Due to the C 5 symmetry, there are two types of vibrations in-plane (a') and

out-of-plane (a"). They are distributed into

Fvib = 30 a'+ 12 a"

All the vibrations are active both in infrared and Raman. The normal co-ordinate

analysis was used after suitable modification to calculate vibrational frequencies and

potential energy distribution. The structural parameters necessary for the compound

are taken from Sutton table [43] and similar molecules. Both for the in-plane and

out-of-plane vibrations, the simplified general valance force field was adopted and

were refined by the damped least square technique. The potential energy

distributions are calculated using final set of force constants. The SVFF is shown to

be very effective in the normal coordinate analysis because of the valance force

constants can be transferred between the structurally related molecules. The normal

co-ordinate analysis and the force field calculations have a salient feature that they

could reproduce the frequencies associated with the skeletal rings as well as the

(-NH2) and (-CH3) groups within a reasonable limit (±10 cm 1) with acceptable

potential energy distribution.

6. VIBRATIONAL ASSIGNMENTS:

The recorded FTIR and FTR spectrum of 2-amino-4-picoline is shown in fig 4. The

131

. I

NH2[a

Fig 2. Molecular Structure of 2-amino picoline

N00N00'CDN00

I—ILaz4I—IL0IL

00

— 7 =--:: ^ ^>

. ---: n000N0000CD0.0co

c0CL

NT

E

0 'E

LL

0 W

O000.0

uJ

N(I)

observed and calculated frequencies of 2-amino-4-picoline along with their relative

intensities and probable assignments are presented in table 3. Assignments have

been made on the basis of relative intensities, magnitude of the frequencies and

mainly on the normal co-ordinate calculations as well as literature data of the

molecules of similar structure. The purity of the normal modes is further confirmed

by calculating the potential energy to each fundamental vibration.

6.1 SKELETAL VIBRATIONS

6.1.1 Carbon-Carbon vibrations

The bands around 1400 cm' to 1650 cm-1 in benzene derivatives are assigned to

skeletal C-C bands. The bands observed at 1491 cm' and 1470 cm' in FTIR and

1484 cm' in FTR have been assigned to C-C aromatic stretching vibrations. The

actual position of the bands are determined not so much by the nature of the

substituents but by the position of the substituents in the ring [47]. The bands at

1635 cm 1 and 1607 cm' in FTIR and 1642 cm' and 1603 cm' in FTR are assigned

to C=C stretching vibration of 2-amino-4-picoline. The medium intensity band

obtained at 856 cm-1 in FTIR corresponds to ring breathing vibration which is in line

with Mohan et al. [54].

The carbon in-plane bending vibration are derived from non-degenerate b1

(1010 cm") and degenerate e2g (606 cm') mode of benzene [47] . The degenerate

frequency 606 cm-1 of benzene splits into two when symmetry is reduced. The

magnitude of one of the component remains almost unchanged while the other is

132

reduced substantially [55]. The band obtained at 849 cm -1 and 842 cm-' in FTR

have been assigned to CCC in-plane bending vibration. In this present work of

2-amino-4-picoline, the out-of-plane vibrations have been assigned to 765 cm' in

FTIR and 756 cm-1 both in infra red and Raman.

6.1. 2 Carbon - Hydrogen vibrations

In aromatic compound the C-H stretching vibration generally lie in the region

3000 cm' to 3100 cm-1 which enables quick identification of the band. They will

not be much affected by the nature of the substituents. Because of the four C-H

bonds in the structure of 2-amino-4-picolifle, it gives rise to four C-H stretching

vibrations. In the present study, the bands at 2914 cm', 2842 cm 1 and 2770 cm 1 in

FTIR and 2914 cm', 2863 cm 1 and 2849 cm-1 in FTR have been assigned to C-H

stretching vibrations . Studies on the benzene spectrum show that there appear two

degenerate e2g (1178 cm) and ej u (1037 cm') and two non-degenerate b2

(1152 c1d) and a2g (1340 cm') frequencies involving C-H in-plane vibrations. C-H

in-plane bending vibrations lie in the region 1000 cm -1 -1100 cm'. By keeping the

above facts in account, the frequencies corresponding to 1307 cm 1 , 1270 cm-1 and

1237 cm 1 in FTIR are assigned to C-H in-plane bending vibrations. The

corresponding C-H in-plane bending vibrations obtained in the FTR are 1307 cm',

1266 cm 1 and 1235 cm1.

The C-H out-of-plane deformation results from b2g (985 cm 1 ), e2 (970 cm1),

elg (820 cm 1 ) and a (671 cm-) modes of benzene and they are expected to occur in

133

the region 600 cm'- 1000 cm'. Even if the frequencies are independent of the

nature of the substituents, they are almost determined by the relative position of the

substituents. Hence the bands obtained at 1177 cm 1 and 1128 cm 1 in FTIR and

1184 cm 1 , 1173 cm-1 and 1128 cm-1 in FTR correspond to 3 out-of-plane C-H

bending vibrations.

6.1.3 Carbon-Amine vibrations

The result of normal co-ordinate analysis is used to assign the band observed at

1335 cm -1 to C-NH2 stretching vibration in FTIR and the counterpart in FTR is

obtained at 1331 cm -1 . The C-NH2 in-plane bending modes are observed at

449 cm in FTIR and 442 cm 1 in FTR. The band that is observed at 307 cm4 both

in FTIIR and in Raman has been assigned to C-NH2 out-of-plane bending vibration.

6.1.4 Carbon-Methyl vibrations

The band observed at 977 cm' in infrared is attributed to the C-CH 3 stretching. The

in-plane bending vibration is observed at 703 cm-1 in infrared and the out-of-plane

bending vibrations are attributed to 521 cm' in FTIR and 514 cm' in Raman.

Almost 25% of the C-CH3 stretching, in-plane and out-of-plane vibrations are

contributed by the CC modes of stretching, in-plane and out-of-plane vibrations

respectively.

134

6.2 GROUP VIBRATIONS

6.2.1 Amino group

Group vibrations were determined in terms of the motions of the nuclei in the

molecules, undergo during vibrations and they appear in fairly constant region of the

spectrum. 2 amino-4-picoline possess one NH 2 group and hence one expects one

asymmetric and one symmetric NH stretching in its spectrum. In amines, the N-H

stretching vibrations occur in the region 3500 cm -1 - 3000 cm' [51]. The

asymmetric -NH2 stretching vibration appears from 3500 cm'- 3420 cm' and the

symmetric -NH2 stretching is observed in the range 3420 cm -1 to 3340 cm-1 . With

reference to this, the vibrational frequencies observed at 3435 cm_ I in FTIR and

3431 cm-1 in FTR are assigned to N-H asymmetric stretching vibration and the

frequency observed at 3307 cm' in FTIR is assigned to N-H symmetric stretching

vibrations. These observations agree well with the earlier work [52-53]. The medium

band in infrared at 1370 cm-1 and the weak band at 1363 cm' in Raman are

assigned to the deformation vibration mode of amino group. Like wise the out-of-

plane bending of amino group or the torsional mode of vibration is assigned to the

weak bands observed at 235 cm' both in FTIR and FTR..

6.2.2 Methyl Group

The major spectral changes in the compound, 2-amino-4-picoline is due to the

substituent (-CH 3) group attached with the ring can have the following types of

vibrations. Symmetric and asymmetric stretching, deformation, rocking, wagging

and torsion. Some of these vibrations are observed and are discussed below.

135

The asymmetric and symmetric stretching vibrations of a methyl group usually

occur at about 2965 cm-1 and 2880 cm' respectively. If the C-H bond is adjacent to

an aromatic ring, the C-H stretching frequency and absorption between 3100 cm1

and 3000 cm-1 can be expected. In the light of the above facts the bands at

3135 cm-1 and 3059 cm' in FTIR and 3049 cm-1 in FTR are attributed to C-H

asymmetric stretching in CH 3. Similarly, the bands at 2977 cm -1 in infrared and

2970 cm-1 in Raman are attributed to C-H symmetric stretching in CH3 . And this

C-H stretching modes of vibrations are considered to be absolutely pure modes,

since the PED contribution of these modes are high.

The CH3 in-plane bending vibrations i.e the deformation and rocking mode of

vibrations are assigned for this molecule as follows. The strong band observed at

1456 cm-1 in FTIR and the weak band of the same frequency in Raman are assigned

to the deformation mode of vibration. The medium intensity band at 1335 cm-1 in

FTIR is attributed to the CH 3 rocking mode of vibration.

The next mode of vibration that has to be assigned is the out-of-plane vibrations of

methyl group. The medium/strong intensity band at 403 cm -1 in FTIR and very

weak intensity band at 407 cm' in FTR are assigned to the wagging mode of

vibration. The medium intensity band at 377 cm-1 in infrared has been assigned to

the torsional mode of vibration.

136

7. POTENTIAL ENERGY DISTRIBUTION

The potential energy distribution has been calculated to check whether the chosen

set of assignments contribute maximum to the potential energy associated with

normal co-ordinates of the molecules. The PED contribution corresponding to each

of the observed frequencies are listed in the table 3.

8. CONCLUSION

The above investigation thoroughly analysed the vibrational spectra both infrared

and Raman of 2-amino pyridine and 2-amino-4-picoline. All the vibrational bands

observed in the FT infrared and FT Raman spectra of these compounds are assigned

to the various modes of vibration. Normal co-Ordinate analysis was also carried out

by transferring the force constants from the structurally related molecules and the

calculated frequencies based on NCA are well within the range of observed

frequencies in the spectra of these compounds. PED was also calculated to check

the correctness of the chosen set of force constants, which reveals the purity of the

mode.

137

Table 1

Initial and final set of potential constants of 2-aminopyridine and 2-amino picoline

Type of force Parameter Coordinates Initial value Final valueConstant Involved

Diagonal constants

Stretching fD C=C 5.601 5.587

fd C-C

2.850

2.712

Jr C-H

4.500

4.534

Is C-N

5.130

5.147

ft C-NH2 5.224

5.001

A

C-CH3 5.047

4.821

Bending

Ia CCC

0.543

0.444

fp CCN

0.315

0.285

fy CNC

0.262

0.216

A

CCH

0.310

0.299

Interaction constants

Stretch-stretch

fDd C=C, C-C

1.434

0.986

fDr C=C, C-H

0.190

0.191

C-N, C-N

0.698

0.486

Stretch-Bend

IDa C=C, CCC

0.360

0.258

Ja C-H, CCC

0.255

0.216

fDp C=C, CCN

0.486

0.392

fD C=C, CNC

0.480

0.386

A

C-N, CNC

0.102

0.112

All stretching force constants are in units of millidynes per angstrom, bending in millidyne

angstrom per square radians and stretching-bending interactions in millidynes per radian

\00en

IVC

)

CIS

C) ,0

C.)

0

o —It 0

'Cl-en

enen

C)

0en

en

-C

l) C

l) C

l)C

l) C

l)

C)

Cl) E

E

E

Et--

c'0

tnen

- \o

NI t 0 cfl '.0

'. en e

—

— 0

en

en

en

en

en

en

en

C)

C)

C)00Cl)

0II4!Cd

•1

:HIz•;

.EbOECl)

C.)Cl)

C)

bO(1)

—400

E

C14N

Cl) 0

0

00

\0

Cl

0

'.0

+0

—4

'—

.—

Cfl

+

C)

Cl)+

+

'.0

r

-U

)

s.r

-<

N

00—

—4. C'I

(N

0Cl)

0

-—

—4 —

4en e

n e

n 00O\

II

Cl)

C)

-4C.)

C)

r/D

C3d

000

00 —

00

00

00

N

tO

tbi

..

.ti.)

ti)ti.)

ttOb

0000

't 0

0

N N

C-

-N

-

N

f r N

t

m C

C.)C.)

C.)I

00'-

4

<<

-

<N

.0N

0.)0.)

0).—

i-

'O

..O

N

N

's.0N

'crN

'4

+

+ '

+

+'

+

cIDN

It +

+

N

+ N

+

+

+

z

,- - m

cn - -

00t 0

0

NC

n N

N

O

cn N

— N

C.) 0 C

.) —

—4 O

\ O

\ -

1-4 N

t

-

ffl

D

N

C\

CIS

n N

-

C C

Cen

enen

EC

f)00

tr) C

14I

II

II

II

II

II

I

C C

enen

E

EN

C N

en N

C C

N

N

N

N

N

C 00

N

N

't

C -

00C

\N

O

C\ C

\ 0

0 N

N N

N

N

N

N

N

- '- -

—4

I -M

10

•

UUUN+U

C14 U

IIII

u

N —

rnN

\O

00

C?

UN00

N

CA

Ii

001

'.0

ci

•'c!3

Cl) (I)

N—4

Cl)

Cd

Cl)

00

N 0

0

fN

—en

c1r)—

4—

4

_C

•

Cl)

Ecn'.0N—4

U U

—' U

Uc

-N

C\

2+

—_

+ ,;

+U

Z

.U

II

,

zU

U U

U U

U-

c,C

N C

'.0 C

CN

N

'.0 '.0 "

N

U00

0.)0)

.E.E

0)

.—

.-'.-

•bi

0.)0.)

-0.)

0.)

0.)0.)

••0

)C

0)

-0

)o

;-4

0I•

o

•()

C.)c

c

0.)b

—0.)

II

I00

.4

—4

u

U N

UU

Z Z

IIII

'.0C

U Z

U N

U

U U

U U

U U

N

U

C

N C

'-4 Q

\ '.0 C

N

C00 N

00It N

N

-

N C

110

'.0'.0

N

E

E

E

'"

C

't-cfl

'00

C N

00 —

'N

C 0

0 N

N

N '

O\ '.

N N

_4

Em

N

S'—I

- -

— —

.- —

EE

cn N

C

10

ON

ON

00

005

UL) U

ZU

U U

:-:-- m

00

r N

N N

+ +

+ +

U U

U U

---

n

'rIt

C)N+

U

z z

UU

U U

U U

U

-, _,

cell

rn

c00

O

NN

- -

N

N+

+ +

+ +

U U

U Z

U U

UZ

U U

U U

U Z

UU

U U

U U

U, U

U,-./',

-,;.

0L

c

--

:-

00 00

—N

00

O

00kn

'(

'It

t1

LbO

.-

.-

.-

..-.

bO

bJb

bO

a)

a)

-. -

• -

• -

• -

• -

..0

a.))

)

a)

•a)

a)

a)

a)

a)

a)

—I

.0 .0 -

bO

.0 .0 .0 c

cda)

a)

)

)

a.)'1

)

. c

(

mm

CC'

C() - •-1 -

- - - 0

o0

0

000C

d

IM4

CL,

C14

iN

2'

.-.-

•- .0

••

.

o

° 0 c

zU

U u

o Z

U U

UU

() U

U U

Z U

U U

U U

- U

U U

U

U Z

OO

C

00

——

N

.-4 —

C\\C

It N

— _4 —

— —

—

I(

C#)

IE

EE

I C N

00 C

C

\ 00

Ni

NIS

N

N c

n

V4

—

—

—

C C

S

00 00

5

I_

—

''

U Z

U U

U\-,-

-C

\oN

+

+Uc_)

zC.)

•'I I Ii

ti)0)

0)0)

Cd

I—

000

0

'i

00—

N

i C

2

. N

m0

N

\C

C

flN

00.—

iC

'0

Qct

C4

—1

\I

I0

IN

Nc\

'z1-

LflQ

00z N

Z Z

00C

tI

'C

ö ö

C

'fl 'fl N

—

U

'l-l

—CN

—m

IcI

00'

Nin

cn

IN

N N

IN

'C

'fl

lE

E

E

EE

E\C

N

i

N 00 0 'C

C

N—

N

C

'f N

s'C

m

N

NCN

0E

rA 2r.

^cd co

..mc

a)

a)01-IU)

0U)

a)

a)cvj

I4 tiiiI— a)

U)

0 IE

0

U)a)'-40ci)

00

0

caca

>—

O

C

00

00

00

m

en

0 0

0

0•-.

•-

•-bO

bO

. _•4•

•-

•-

•,-4•,-4

o

C)

C)

#•

C)

C)

ci)a)

a)

a)U

),

S

U)

U)

O

,U

)Q

If)U

)

C)+

U)

IfU

)±

ciU

)

Cd

Lf

Cd

Q

U)

z z

4'° — 0

c 0

— 0

C\

Itr C

en en

enen

N

E

'00 C

C)

enN

S

C C

C

\

enN

U)

E

E

E00 5

en

C '

C) If)

1-4-4 C

C C

C)

en N

en

en

en

en

a-,

-,

en

CNr-

00 00

00

tob

b.

.e1)

)

bJtO

en

C

CC

—

u

N

N C

C:)

f_

I.N

L

fl N

00

C

—

.)t)

'- N

C

't

It

O' 00

ON

+ bb +

C

r- +

,- —

+

N

11C

CO)en N

N

++

C

—'

+110 z

It fl N

— N

N

'N

< N

00 C

fl

en

< N

N 0

- 0 0 —

N

N —

C

N

—4

C00 N

N

N N

E

P00NE

I "N

C

N

en

N

en

c\

len

N C

C

't —

t C

t—

00 N

N

O

'r

en

N N

N N

N N

N

N

N N

N

N

N

cq

II

II

N- Q

0

\0—

4 —

4

O\

-It

00—

4 —

4cn

It

—4

C)

—4

+

C) C

)11

11C

) C

)C00

00

C)

CN I

C) C

)——

N N

+

+ +

II

C) C

)

coC

IO

c

.O

—

0

0 —

N 00 00

bbO

..

..

..)

)

..'

0

0bO

boo

.-4—

o

0Ifl L

fl C

N

. N

2 o _

cn c

N

C

Q N

40

, to

n

..0'i

Cfl—

—

4—

tn

110c

c4

C'I

Itt + +

+

C

) +

fl C

) C

) ±

C

) C

) C

)

cnz

GIN

O\

O\

C\

00II

IIII

NIt N

U

C

)

It Z

C

) C

) C

) Z

—4

C"

0C

1-4

—4

00—

It

—4

\0cfl

000

'fl \C

)I r

It

It

Nt

—4 —

4 —

4 —

4 —

4

N'I

N N

"0 '

C \C

C

IN

'C

N

C\ N

tn

It

I —O

IN00

N N

mN

N

.-4

—

,-4

—4

'cr3c

-

00'.0+

-4

+0 0

Zo

0Z

0

0

0 .

-4

m

'.0+

-4

N

'.0

+

+

+

zz N

Qz

0000

00

000

c.

cr.

- m

Q

—

N

C

—

00 Itt C

'II00

N

N

'.0 N

'1N

(( —

to w

bO

to

to

bD 1)-

-a)

a)

a.)a)

a)

a.) a.)

.'1)

a.))

o

-—

—

—

a)

a)

)

— —

0 0 9

a)P

4

0404'

'.0en

II

N

'0 0 +

N

ZN

fl Z

0C

<I

0 0

00000 m

N

00

000N

00 0

0.

O\

00

'r

00

bO

—In

1+

m

bO-4 —

N0

1 10'-4

It

-

N

000

N C

110 c

fl

N '.0

Nm

fl N

N1-4

1-4

-4

4,

0\ C

N N

0\

C'0

-4

N

In0

00

Et

NNaN

'rC

fl 00

Ncn C

'.0 fl 0

0 N

N N

fl N

N

—

— C

1-4

—

1-4

-4

'-4

1-4

II

I

E E

0 In

'0'n

cn In

ONON

00

C/)

Cl)

:E

I N

C

N

N

00 C

N

I cn 0

N

m

N' N

N

00I

) N

N

—

- C

C

o

'0303

Cd_C

C1

CItt

00 C

'.0

'.0

'.0

C'n

n

*t)-4

C

110C

N

00

M 00 fl

t C

It

00 N

N

N

'.0

+z0N+I!

000

0o L) 0

0 -

' 0 0

:-en

— N

NN

++

++

+,-;;

++

'000

G' u

z

00 0

00 0

o

Z0

0 Z

0 0

0000

\_

-,

\__

Co.

Co.

-:-

N O

--1

00

—

00

110O

110C

flfl

"

"

tIO

'-4

Ob1J

O•,

bO)

ti)

0.)0.)

0.)0.)

0.)—

- c

c 0)

C14

C^4

0)0.)

0)0)

0.)

en

enC

)N

0cn.

. •-

0

N

..

CN

00

00

0+

o .- z

00 0

000

0 Z

00

0 Z

OO

ON

'- -

00

0

N

0.)00.)

0

E E

(i It

I I

I I

'.0en

iIt

It

00S

In00

00 r-

>>

'.o en 'n

C

S

-4 C

00C

en C

N

N N

N

N N

'.0

'.0

In

N

•'cv

•'•'

N'-4

C00NN

CCCn

II

II

I

NC

Ni

NCCn

0

Cd

cdD

E(IDt.)

(IDEEa)(ID00a)

+

C'I

0'

z

''0'—I

s::-

9O

O

—

NN

—

C4

++

+

+

+

Z 0 0

0

00

o —

0 C

N

-

flN

toto

O)ti)

to

si.)c)

)—

— —

oo •—

0

ob1tocq

jN

-fl cfl C

o

0

N B

N

C

'C

*,0

00

C?

r

r

--

C"

0 Z

"0 It C

Z

z—

'fl00

erI

Z 00 N

O —

N

N

'—

0

Z

E E

E—

cn

•C

01%

00 0

0

NN

C

00 N

N

N C

cn m

Cfl

•1

I'-)N

REFERENCES

1. Bogen K.T and Keating G.A, J. Esposure-Analysis-and-Environmental-

Epidemiology 11 (2001) 155.

2. Thorgeirsson S.S, Davis C.D, Schut H.A, Adamson R, Snyderwine E.G,

Princess-Takamasu-Symp., 23 (1995) 85

3. Glaab W.E, Kort K.L, Skopek T.R, Cancer-Research, 60 (2000) 4921

4. Knize M.G, Sinha R, Brown E.D, Salmon C.P, Levander O.A, Felton J.S and

Rothman N, J. Agricultural-and-food-chemistry, 46 (1998) 4648.

5. Smith R.C, Emmem H.H, Bertels Mann F.W, Kulig B.M, Van Loenen A.C, and

Polman C.H, Neurology, 44 (1994) 1701.

6. Hogent Camp and Derk, J. Handbook of Am. Chem. Soc. (2001).

7. Loont Jens, Jacobus Antonius, Clauswitz and Kai Uwe, Plastics. Manufacture

and processing (2001)

8. Muller W.E, Pergande G, Ushijima H,Schleger C, Kelve M and Perovic 5,

Prog. Mol.Subcell-Biol., 16 (1996) 44.

9. Bludsky 0, Sponer J, Leszczynski J, Spirko V and Hobza P, J. Chem. Phy. 105

(1998) 11042

10. HYPERLINK http://www.wheelweb.com/aminopyridine.htm

www.wheelweb.com/2-aminopyridine.htm

11. Sheam G.T, Murray N.M.F, Rothwell J.C, Miller D.H and Thompson A.J Brain

121 (1998).

138

12. EXTOXNET, http//ace.ace.orst.eduJinfO/eXOtOXfletIPiPst4T1in0P.htm.

13. www.chemicalland 21.com/arokarhi/lifescience/ago/3- aminopyridine.htm

14. Schwarz S.J, Claus J.R, Wang H, Math Ott N.G, Graham P.P and Fernandes

C.F Poult. Sci., 76 (1997) 1450

15. www.chemicalland 21.com/arokarhi/lifescience/Phar/2- aminopyridine.htm.

16. Krow, Grant R, Xiao, Yushi, Cannon, Kevin, Swan, ScotA, Nickel and Andrew,

Synthetic Communications, 30 (2001) 4093

17. Cheng, Kezhan, Nordmeyer, Francis R, Lamb and John D, J. Capillary.

Electrophoresis, 2 (1995) 279

18. Natsuka, Shunji, Hare and Sumihiro, Methods in Mole. Bio., 76 (1998) 101

19. Araki Y, Andoh A, FujiyamaY, Hata K, Makino J, Okuno T, Nakanura F.

Bamba T, J. Chromatography B: Biomedical Sciences. and Applications, 753

(2001) 209

20. Nizamuddin, Khan, Mukhtar Hussain, Srivastava, ManojKumar, Tiwari and

Shailendra, Indian J Chem. Sec B & Chem. including Medical Chem., 398

(2000) 853.

21. Boer, Rainer, Ulrich, Wolf Rudiger, Klein, Thomas Mirau, bent, Haas, Sabine,

Baur and Ilka, Mole. Phamacology, 58 (2000) 1026.

22. Castillo 0, Luque A, Julve M, Lioret F and Roman P, Inorganica Chimica

Acta, 315 (2001)9.

23. Lee, Dae Yon, Jun, Chul Ho, Moon and Choong Woon, J. Organic Chemistry,

67 (2002) 3945.

139

24. Das M.K, Maiti P,K, Roy S, Mittakanli M, Morse K.W, Hall LH, Arch. Pharm-

Weinheim, 325 (1992) 267

25. Zemity S.R and Radwan M.A, Pesticide Science, 55 (1999) 1203

26. el-Naggar M.M, J. Inorg-Bio. Chem., 65 (1997) 263

27. Ita B.L and Offiony O.E, J. Pure and Appi. Sciences, 6 (2000) 51

28. Cannata, Vincenzo, Tamagnore, gain F, Piani, Silvano, Campana, Manula and

Da Roit, Giovanni. Can., (1986) 30

29. Gunasekaran S, Vardhan R.S and Manoharan K, Indian J. Phys., 67(1993)95.

30. Padhye M.R. and Bhujle V.V, Indian J. Pure and Appi. Phys., 8 (1970) 479

31. Baruah G.D, Ammani AmmaR, Dube P.S and Rai S.N, Indian J. Pure and

Appi. Phys., 8 (1970) 761.

32. Sanyal K.N, Srivastava S.1 and Mrs. Ananda Devi, Indian J. Pure and Appi.

Phys., 21(1983) 56.

33. Grech E, Malarski Z, Sobczyle L, Potier J and Roziere J, J. Mole. Str., 175

(1988) 23

34. Kydd R.A. Spectrochim. Acta 35A (1979) 409

35. Akyoz S, J. Mole. Str., 175 (1988) 365

36. Kimie Sasaki, Ichiro Kuwano and Koyo Aida, J. Inorg. Nuci. Chem., 43 (1981)

485

37. Baron J, Malarski Z, Sobczyle and Erreach B, Spectrochim. Acta, 44A (1988)

993

38. Carmona P, Molina M and Escobar R, Spectrochim. Acta 49A (1993) 1

140

39. Fulirer H, Kartha V.B, Kidd K.L, Kruger P.J and Mantsch H.H, Computer

program for infrared and spectrometry. Normal co-ordinate analysis vol.5,

national research council, ottawa, Canada 1976.

40. Wilson E.B, J. Chem. Phys., 7 (1939) 1047

41. Wilson E.B, J. Chem. Phys., 9 (1947) 76

42. Wilson E.B, Decius J.0 and Cross P.C, Molecular vibrations, MC

Graw Hill, Newyork (1955).

43. Sutton L.E. The interatomic Bond distances and Bond angles in Molecules and

Ions. London Chem-Soc. London (1958)

44. ACD/Chemsketch, Version 3.5, Advanced Chemistry Development Inc. Canada

(1998)

45. Varsanyi G; Vibrational spectra of Benzene derivatives, Akademiai

Kiado, Budapest (1969)

46. George W.O and Mcintyre P.S. Infrared Spectroscopy. John Wiley &

Sons, London (1987)

47. Bellamy L.J, The Infrared Spectra of Complex Molecules, Wiley, New

York 1959.

48. Tripathi R.S, Indian J. Pure Appl. Phys., 11(1973) 277

49. Sharma S.N and Dwivedi C.P, Indian J. Pure and App!. Phys., 13 (1975) 670

50. Green J.H.S, Spectrochim Acta, 18 (1962) 39

51. DilellaD.P and StidhamH.D, J. Raman Spectrosc., 9 (1980) 90

52. Lopez Tocon I, Wolley M-S, Otero J.0 and Marcos J.I, J. Mol.Struct.,

470 (1998) 241

141

53. Arenas J.F, Lopez Tocon I, Otero J.0 and Marcos J.I, J. Mol. Struct., 476

(1999) 139

54. Mohan S, Murugan R and Srinivasan S, Proc.Nat. Acad. Sci. India

62 (1992)154

55. Johri G.K, Prakash V and Srivastava C.L, Indian J. Pure and Appi.

Phys., 14 (1976) 418.

142