Synthesis, structural and spectral analysis of (E)-N′-(4- Methoxybenzylidene)pyridine-3-carbohydrazide dihydrate by density functional theory

Article abstract of DOI:10.1016/j.saa.2014.08.014

New nonlinear optical crystal, (E)-N′-(4-Methoxybenzylidene)pyridine- 3-carbohydrazide dihydrate (MBP3CD 2H2O) has been synthesized and grown as a single crystal by the slow evaporation solution growth technique. The compound was characterized by FTIR (40

Full text of DOI:10.1016/j.saa.2014.08.014

Accepted Manuscript
Synthesis, Structural and Spectral Analysis of (E)-N′-(4-Methoxybenzyli-
dene)Pyridine-3-Carbohydrazide Dihydrate by Density Functional Theory
K. Govindarasu, E. Kavitha, N. Sundaraganesan, M. Suresh, M. Syed Ali
Padusha
PII:
S1386-1425(14)01196-2
http://dx.doi.org/10.1016/j.saa.2014.08.014
SAA 12535
DOI:
Reference:
To appear in:
Spectrochimica Acta Part A: Molecular and Biomo-
lecular Spectroscopy
Received Date:
Revised Date:
Accepted Date:
18 May 2014
14 July 2014
7 August 2014
Please cite this article as: K. Govindarasu, E. Kavitha, N. Sundaraganesan, M. Suresh, M. Syed Ali Padusha,
Synthesis, Structural and Spectral Analysis of (E)-N′-(4-Methoxybenzylidene)Pyridine-3-Carbohydrazide
Dihydrate by Density Functional Theory, Spectrochimica Acta Part A: Molecular and Biomolecular
Spectroscopy (2014), doi: http://dx.doi.org/10.1016/j.saa.2014.08.014
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers
we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and
review of the resulting proof before it is published in its final form. Please note that during the production process
errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

SYNTHESIS, STRUCTURAL AND SPECTRAL ANALYSIS OF (E)-N′-(4-
METHOXYBENZYLIDENE)PYRIDINE-3-CARBOHYDRAZIDE DIHYDRATE BY
DENSITY FUNCTIONAL THEORY
a
a
a
b
b
K. Govindarasu , E. Kavitha *, N. Sundaraganesan , M.Suresh and M. Syed Ali Padusha
a
Department of Physics (Engg.), Annamalai University, Annamalainagar-608 002, India.
b
PG & Research Department of Chemistry, Jamal Mohamed College, Tiruchirappalli-20, India.
Abstract:
New nonlinear optical crystal, (E)-N′-(4-Methoxybenzylidene)pyridine-3-
carbohydrazide dihydrate (MBP3CD∙2H2O) has been synthesized and grown as a single crystal
by the slow evaporation solution growth technique. The compound was characterized by FTIR
-1
-1
(
4000-400 cm ), FT-Raman (3500-50 cm ) and UV–VIS (800-200 nm) spectroscopy. The
optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of
MBP3CD∙2H2O have been investigated experimentally and theoretically using Gaussian03
software package were performed using B3LYP method with the 6-31G(d,p) basis set. Stability
of the molecule arising from hyperconjugative interactions, charge delocalization have been
analyzed using Natural Bond Orbital (NBO) analysis. The calculated first hyperpolarizability is
comparable with the reported values of similar derivatives and is an attractive object for future
studies of nonlinear optics. The HOMO and LUMO analysis is used to determine the charge
transfer within the molecule. In addition, molecular electrostatic potential (MEP), frontier
molecular orbital (FMO) analysis were investigated using theoretical calculations. The Chemical
reactivity and thermodynamic properties (heat capacity, entropy and enthalpy) of
MBP3CD∙2H2O at different temperature are calculated.
Keywords: (E)-N′-(4-Methoxybenzylidene)pyridine-3-carbohydrazide dihydrate; TD-DFT;
NBO; UV-Vis; FTIR; FT-Raman.
*
Corresponding author
E-mail:eswarankavitha@gmail.com
Tel: +91 9442477462
1

1
. Introduction
The design and synthesis of organic molecules exhibiting nonlinear optical (NLO)
properties have been motivated by their potential for applications in optical communications,
optical computing, data storage, dynamic holography, harmonic generators, frequency mixing,
and optical switching [1,2]. Recently much progress has been made in the development of new
NLO organic materials having large nonlinear optical coefficients. The desire to utilize the
properties of these materials has created need for new materials with very large second order
susceptiblies for various applications [3–6]. Hydrazones have attracted much attention for their
excellent biological properties, such as antimicrobial, anti-convulsant, analgestic, anti-
inflammatory, antiplatelet, antitubercular, anticancer, antitumor [7] antiviral and vasodilator
activities [8] . Hydrazones possessing azomethine –NHN═CH– groups constitute an important
class of compounds for new drug development [7]. Moreover, hydrazones derived from 2-
acetylpyridine are known to inhibit the proliferation of tumour cells to a greater extent compared
to standard anticancer agents [9].The title compound (molecular formula;C H N O .2H O),
14
13
3
2
2
comprises one benzohydrazide molecule and two water molecules. Title compound crystallizes
with monoclinic system with cell parameters a = 7.6534 (6) Å, b = 16.3503 (11) Å, c = 11.4887
(
6) Å, β = 96.889 (2) ° and space group P2 /n [10].
1
Jayarama et al [11] reported molecular synthesis, growth, and characterization of 3-(4-
Methoxyphenyl)-1- (pyridin-2-yl) prop-2-en-1-one single crystal: A potential NLO material. B.
Ganapayya et al [12] investigated synthesis, growth, and characterization of a new NLO material
3
-(2, 3-dimethoxyphenyl)-1-(pyridin-2-yl) prop-2-en-1- one. The literature survey reveals that to
the best of our knowledge, no experimental and computational vibrational and UV spectroscopic
study on MBP3CD∙2H2O have published in the literature yet. Therefore, the present work
mainly deals with complete description on the molecular geometry, molecular vibrations,
conformational stabilities, infrared intensities, Raman intensities, and electronic features of the
MBP3CD∙2H2O. Vibrational spectra of MBP3CD∙2H2O have been analyzed on the basis of
calculated total energy distribution (TED). Theoretically computed vibrational wavenumbers
were compared with experimental values. The natural bond orbital (NBO) analysis can be
employed to identify and substantiate the possible intra and intermolecular interactions between
the units that would form the H-bonded network. The UV-Vis spectroscopic studies along with
HOMO–LUMO analysis have been used to explain the charge transfer within the molecule.
2

Finally, the thermodynamic properties of the optimized structures were theoretically analyzed.
The results of these spectroscopic and theoretical studies are reported herein.
2
2
. Experimental
.1. Synthesis
Anisaldehyde (1.2 ml, 0.01mol) and benzoic acid hydrazide (1.37 g, 0.01mol) were added
to ethanol (10 ml) of and stirred for an hour in the presence of hydrochloric acid to form a white
precipitate. The precipitate was washed with sodium bicarbonate solution and filtered and again
washed with petroleum ether (40–60%) and dried in air. The compound was recrystallized from
absolute ethanol.
2
.2. FT-IR, FT-Raman and UV–Vis spectral measurements
The FT-IR spectrum of (E)-N′-(4-Methoxybenzylidene)pyridine-3-carbohydrazide
-1
dihydrate compound was recorded in the range of 4000-400 cm on a Perkin Elmer, RXI model
FT-IR spectrometer using KBr pellet technique. The spectrum was recorded in the room
-1
-1
temperature, with scanning speed of 10 cm , and spectral resolution: 4 cm . FT-Raman
spectrum of the title compound was recorded using 1064 nm line of Nd:YAG laser as excitation
-1
wavelength in the region 3500-50 cm on a BRUKER RFS 27: FT-Raman spectrometer
-1
equipped with FT-Raman molecule accessory. The spectral resolution was set to 2 cm in back
scattering mode. The laser output was kept at 100 mW for the solid sample. The ultraviolet
absorption spectra of MBP3CD∙2H2O were examined in the range 200-800 nm using Perkin
Elmer, lambda-35 model UV spectrometer. The UV pattern is taken from a 10-5 molar solution
of MBP3CD∙2H2O, dissolved in DMSO solvent. The FTIR and UV-Vis spectral measurements
were carried out at Saint Joseph College, Tiruchirappalli and FT-Raman spectral measurement
was carried out at Indian Institute of Technology (IIT), Chennai, India.
3
. Computational details
All theoretical calculations were performed with the program package Gaussian 03W.
13] DFT with the B3LYP functional [14, 15] was used for the optimizations of the ground state
[
geometries and simulation of the vibrational spectra. The optimized geometry corresponding to
the minimum on the potential energy surface was obtained by solving selfconsistent field
equation iteratively. In the process of geometry optimization for the fully relaxed method,
convergence of all calculations and the absence of imaginary values in the wavenumbers of the
normal modes confirmed the attainment of global minima on the PES. After molecular
3

optimization, a theoretical wavenumber calculation was performed using the same basis set, in
order to predict the IR and Raman spectra of the molecule. An empirical scaling factor of 0.9608
[
16, 17] was used to offset the systematic error caused by neglecting anharmonicity and electron
correlation. Natural bond orbital (NBO) calculations of MBP3CD∙2H2O were performed at the
B3LYP/6-31G(d,p) level using the program NBO 3.1 [18] included in the Gaussian 03W
program[13]. Furthermore, theoretical vibrational spectra of the title compound were interpreted
by means of TED using the VEDA 4 program [19]. The first order hyperpolarizability (β ) of this
0
molecular system, and related properties (β, α and ∆α) of the title molecule are calculated using
0
HF/6-31G(d,p) level of theory, based on the finite-field approach [20]. UV–Vis spectra,
electronic transitions, vertical excitation energies, absorbance and oscillator strengths were
computed with the time-dependent DFT method. The electronic properties such as HOMO and
LUMO energies were determined by TD-DFT approach. To investigate the reactive sites of the
title compound the MEP were evaluated using the B3LYP/6-31G(d,p) level of calculation. The
theoretically predicted IR and Raman spectra at B3LYP/6-31G(d,p) level of calculation along
with experimental FT-IR and FT- Raman spectra are shown in Figs.1 and 2.
4
. Prediction of Raman intensities
The Raman activities (S ) calculated by Gaussian 03 program [13] have been converted to
i
R
R
relative Raman intensities (I ). The theoretical Raman intensity (I ), which simulates the
measured Raman spectrum, is given by the equation [21, 22]:
R
4
-1
-1
I = C (ν − ν ) ν B S …………………………………. (1)
i
0
i
i
i
i
Where B is a temperature factor which accounts for the intensity contribution of excited
i
vibrational states, and is represented by the Boltzmann distribution:
B = 1 – (exp hν c/kT)……........…………………………. (2)
i
−
i
In Eq. (1) ν is the frequency of the laser excitation line (in this work, we have used the excitation
0
−
1
frequency ν = 9398.5 cm , which corresponds to the wavelength of 1064 nm of a Nd:YAG
0
−
1
laser), ν is the frequency of normal mode (cm ), while S is the Raman scattering activity of the
i
i
R
−12
normal mode Q . I is given in arbitrary units (C is a constant equal 10 ). In Eq. (2) h, k, c, and
i
i
T are Planck and Boltzmann constants, speed of light and temperature in Kelvin, respectively.
4

Thus, the presented theoretical Raman intensities have been computed assuming B equal 1. The
i
theoretical Raman spectra have been calculated by the Raint program [23]. The simulated spectra
-1
were plotted using a Lorentzian band shape with a half-width at half-height (HWHH) of 3 cm .
5
5
. Results and discussion
.1. Conformational stability
To found stable conformers, a PES scan analysis was carried out for the MBP3CD∙2H2O
compound. Conformational space of the title compound was scanned by semi empirical method
and then full geometry optimizations of these structures were performed by B3LYP/6-31G(d,p)
level of theory. The scan was carried out by minimizing the potential energy in all geometrical
parameters by changing the torsion angle every 10° for 360° rotation around the bond. In order to
explain the conformational flexibility of the title molecule, the energy profile as a function of T
(9N-7C-2C-1C), T (10N-9N-7C-2C) and T (12C-11C-10N-9N) torsion angles were achieved.
The conformational energy profile shows one maxima at 150° having the energy -955.897
Hartree and one local minima (stable conformers) at 0 or 360° having the energy -1008.84
Hartree for torsion angle T(9N-7C-2C-1C) shown in fig.3a. Similarly from the figs 3b and 3c
shows one maximum at 10° having the energy -1004.2 Hartree and at 20° having the energy -
1
1
005.21 Hartree and one minimum near 0 or 360° having the energy -1005.29 Hartree and -
005.72 Hartree for the torsion angles T(10N-9N-7C-2C) and T(12C-11C-10N-9N) respectively.
Further results are based on the most stable conformer of MBP3CD∙2H2O molecule to clarify
molecular structure and assignments of vibrational spectra.
5
.2. Structural analysis
A complete geometrical optimization was performed within the C1 point group symmetry
and the optimized molecular structure of the most stable conformer of MBP3CD∙2H2O at
B3LYP method is shown in Fig. 4. The calculated optimized structural parameters such as bond
lengths, bond angles and dihedral angles of MBP3CD∙2H2O by B3LYP method was given in
Table 1.The results are compared with the experimental X-ray diffraction data [10].
The values for all the bond lengths and bond angles have small deviation with the
experimental results are calculated by 6-31G(d,p) basis set. This is due to the theoretical
calculations are performed for an isolated molecule in gaseous phase and the experimental
results are for a molecule in a solid state. The MBP3CD∙2H2O molecule contains an electron
donor methoxy group attached to the carbon (C15) atom of phenyl moiety and the carbonyl
5

group (C═O) along with the pyridine moiety at the other end acts as an electron acceptor. The
charge transfer takes place through the π-conjugation between the electron donor and acceptor
groups. This molecule has twelve C─H bonds, twelve C─C bonds, one C═O bond, one N─H
bond, one C═N bond and four OH bonds. In the benzene ring, C-C bond length is about 1.396 Å
[
24]. The calculated C–C bond length in phenyl ring varies from 1.383-1.401Å by DFT method
which is good agreement with experimental data (1.382-1.400 Å). On the other hand C–C bond
length of the pyridine ring varies from 1.390-1.402 Å; these values are very closer to
experimental XRD values (1.370-1.381).The bond length C2─C7 has the highest value (C2─C7
=1.503 Å by DFT, 1.493 Å by XRD) when compared to other C─C bond lengths. With the
electron donating (methoxy) substituent on the benzene ring, the symmetry of the ring is
distorted, the bond length C14─C15=1.400 Å and C15─C16=1.407 Å which is longer than
C13─C14=1.395 Å and C16-C17=1.383 Å by DFT method at the rest of the substitution. The
C─H bond length of the phenyl and pyridine ring varies from 1.083 Å -1.088 Å which is slightly
greater than that of experimental values (0.930 Å).On the other hand small increment occur in
methoxy group C─H bond lengths C19─H30=1.091 Å, C19─H31=1.098 Å and
C19─H32=1.097 Å by DFT method. The calculated N─H bond length is N9─H24 = 1.021 Å by
DFT method, which is 0.161 Å deviate from the experimental value (0.860 Å). The C7─N9 and
C10═N11 bond lengths calculated by DFT method is 1.371Å and 1.287 Å respectively. The
O─H bond lengths of the water molecules vary from 0.965 Å -0.975 Å by DFT method which is
slightly greater than experimental data (0.814 Å -0.830 Å).
The pyridine ring appears to be a little distorted because of the C═O group substitution as
seen from the bond angles C1–C2–C3, which are calculated as (117.5°) by B3LYP method
which is deviate from the typical hexagonal angle of (120°). With the electron donating
(methoxy) substituents on the benzene ring, the symmetry of the ring is distorted, yielding ring
angles smaller than (120°) at the point of substitution [25]. Due to the electron donating effect of
methoxy group, it is observed that the bond angle at the point of substitution C14-C15-C16
(119.4°) by DFT method, which is good agreement with experimental data (119.9°). The
hydrazone molecule adopts an E conformation with respect to the C11═N10 bond with the
torsion angle (C7─N9─N10─C11) of (176.99°) calculated by DFT method, (177.41°) observed
by XRD data.
6

The methoxy group is co–planar with the benzene ring to which it is bound with the
torsion angle (C14─C15─O18─C19 = ─0.34°) by DFT method which is well agreement with
observed value (-0.26°).The comparison of observed and calculated hydrogen bond geometries
are shown in Supplementary material S1. The molecules of benzohydrazide and water are
iii
linked by N9—H24···O36W, O33W—H35···N10 and O33W—H35···O8 hydrogen bonds
network. From the Supplementary material S1 we concluded that the calculated hydrogen bond
geometry values good agreement with experiment findings. Thus MBP3CD∙2H2O molecule
possesses a D-π-A type push-pull structure where charge transfer is from donor end to acceptor
end of the molecule. This ensures the electronic delocalization within the molecule which helps
to possess optical nonlinearity.
5
.3. Vibrational assignments
Infrared and Raman spectroscopic techniques provide important structural information
making them a powerful molecular investigation tool. The aim of the vibrational analysis is to
find vibrational modes connected with specific molecular structures of calculated compound.
The observed (FTIR and FT-Raman) wavenumbers, calculated IR and Raman intensities and
assigned wavenumbers of vibrational modes calculated at the B3LYP level using basis set 6-
3
1G(d,p) along with their TED of MBP3CD∙2H2O are depicted in Table 2. According to the
theoretical calculations, MBP3CD∙2H2O has a planar structure of C1 point group symmetry. The
molecule has 38 atoms and 108 normal modes of fundamental vibrations. All the 108
fundamental vibrations are active in both IR and Raman. In order to facilitate assignment of the
observed peaks; we have analyzed the vibrational wavenumbers and compared our calculated
values with the experimental results. The small difference between the experimental and
calculated vibrational modes could be attributed to the fact that the experimental results belong
to solid phase while the theoretical belong to isolated gaseous phase. The calculated vibrational
frequencies were scaled in order to improve the agreement with the experiment values. In our
study we have followed scaling factor of 0.9608 for B3LYP/6-31G(d,p) [16,17]. After scaling
-1
with a scaling factor the deviation from the experiments is less than 10 cm with few exceptions.
For visual comparison, the observed and simulated FT-IR and FT-Raman spectra are represented
-1
in Figs.1 and 2 respectively. The bands observed in the measured region 4000–400 cm arise
from the vibrations of protons in the hydrogen bonds, the internal vibrations of the
benzohydrazide cations, water molecules and the vibrations of both N─H….O and O─H…..O
7

-1
hydrogen bonds. The bands below 200 cm in the infrared and Raman spectra arise from the
lattice vibrations of the crystal. The vibrational assignments for different functional groups have
been discussed below.
5
.3.1. C–C vibrations
The ring stretching vibrations are very much important in the spectrum of benzene,
pyridine and their derivatives are highly characteristic of the aromatic ring itself. Carbon–carbon
−
1
ring stretching vibrations occur in the region 1430–1625 cm . In general, the bands are of
variable intensity and are observed at 1625–1590, 1575–1590, 1470–1540, 1430–1465 and
−
1
1
280–1380 cm from the wavenumber ranges given by Varsanyi [26] for the five bands in the
-1
region. In the present study, the C─C stretching vibrations are found at 1601(vs) cm in IR and
-1
at 1604(s) and 1155 (m) cm in Raman spectra for Benzene ring. The computed wavenumbers at
-
1
1
600, 1554, 1499, 1410, 1310 and 1158 cm by DFT method assigned C─C stretching
-1
vibrations for the Benzene ring. The band observed at 1511 cm with high intensity in IR and
-1
1
571 and 1512 cm in FT-Raman with medium intensity identified as C─C stretching vibrations
-1
for the pyridine ring. These vibrations also computed at 1581, 1558, 1539 and 1266 cm by DFT
-1
method for pyridine ring. The strong band observed at 1127 cm in FTIR spectrum and
-
1
calculated at 1128 cm by DFT method identified as C2─C7 stretching vibration. Also
-1
-1
C11─C12 stretching vibration observed at 1066 cm in FTIR and 1065 cm in FT-Raman
-1
spectrum. The predicted wave number at 1056 cm assigned C11─C12 stretching vibration. The
-1
C─C─C inplane bending bands always occur between the value 1000- 600 cm [27]. The bands
-1
-1
observed at 496 cm in FT-IR spectrum and 471 cm in FT-Raman spectrum for
MBP3CD∙2H2O are assigned to C─C─C deformations of phenyl ring. The theoretically
-1
computed value at 985, 898, 627 and 494 cm by DFT method gives excellent agreement with
-1
experimental data. The observed wavenumber with weak intensity at 607 cm in FT-Raman
spectrum is identified C─C─C inplane bending vibration of pyridine ring. The predicted
-1
wavenumber at 1001, 897 and 608 cm is assigned C─C─C inplane bending vibration of
pyridine ring. The TED contribution for this mode is a mixed mode as it is evident from Table
-1
2
.The strong band observed at 531 cm in FT-IR spectrum in MBP3CD∙2H2O molecule is
assigned to C–C–C─C torsion bending vibration for the benzene ring. The computed
-1
wavenumber for these modes are at 897, 705, 534, 427 and 418 cm assigned C–C–C─C torsion
-1
bending vibrations for the benzene ring. The observed weak intensity peak at 398 cm in FT-
8

Raman spectrum found to be C–C–C─C torsion bending mode (mode. no; 81) for pyridine ring.
-1
The calculated wavenumber at 397, 382 and 164 cm (mode. no’s; 81, 82 & 96) are assigned as
C–C–C─C torsion bending mode for pyridine ring.
5
.3.2. C─H vibrations
The heteroaromatic organic compounds and its derivatives are structurally very close to
-1
benzene and commonly exhibit multiple week bands in the region 3100–3000 cm due to C–H
stretching vibrations [38]. There are four C─H stretching modes for disubstituted benzenes.
According to selection rules, all four bands are allowed in the IR spectrum [29]. The calculated
-1
values are 3096, 3085, 3048 and 3039 cm and only one band is observed in the IR spectrum at
-1
3
099 cm are identified as C─H stretching vibrations of phenyl ring. The weak intensity bands
-1
observed at 3072 and 3054 cm in FT-Raman spectrum identified as C─H stretching vibrations
-1
of pyridine ring. The calculated wavenumber at 3101, 3081, 3057 and 3045 cm by DFT method
are assigned as C─H stretching vibrations of pyridine ring, which is good agreement with
experimental values and TED contributes almost above 80%. The computed wavenumber at
-1
2
946 cm (mode. no; 16) was assigned C11─H25 stretching vibration, which is evident from the
table 2, TED exactly contribute to 100%. The C–H in-plane bending vibration is usually
-1
expected to occur in the region 1300–1000 cm and these vibrations are very useful for
characterization purpose [30]. The bands due to C–H in-plane bending vibration interact
somewhat with C–C stretching vibrations, are observed as a number of bands in the region 1297
−
1
−1
and 1066 cm in FTIR and 1299, 1155 and 1065 cm in FT-Raman spectrum whereas these
−
1
bands were computed at 1410, 1298, 1158, 1107 and 1056 cm by DFT method assigned C–H
in-plane bending vibration for our MBP3CD∙2H2O molecule. The out-of-plane CH deformations
-1
[
31] are observed between 700 and 1000 cm . Generally the CH out-of-plane deformations with
the highest wavenumbers are weaker than those absorbing at lower wavenumber. The strong CH
-1
band occurring at 840 ± 50 cm , is typical for para substituted benzenes [31]. In the present
-1
work the observed wavenumbers with weak intensity at 1029, 941 and 716 cm in FTIR
-1
spectrum and 773 and 722 cm in FT-Raman spectrum are identified as CH out off plane
bending vibration. Theoretically predicted wavenumbers at 1025, 953, 897, 811, 787, 720, 705,
-1
7
00 cm are assigned to  bending vibrations; these values are also good agreement with
CH
experimental values.
.3.3. O─CH vibrations
5
3
9

In aromatic methoxy compounds, υ of CH are expected in the region [31] 2985 ± 20
as
3
−1
-1
and 2955 ± 20 cm . In our title molecule the computed wavenumber at 2958 cm assigned to
C─H asymmetric vibration. The TED exactly contribute to 99% for this mode (mode. no; 15).
−1
The symmetrical stretching modes υsym of CH is expected in the range 2845 ± 45 cm in which
3
-1
all the three CH bonds extend and contract in phase [31]. The strong band observed at 2841 cm
-1
in FTIR and weak intensity Raman band at 2842 cm identified to symmetric stretching
-1
vibrations of the methyl group. The computed wavenumbers at 3027 and 2898 cm are assigned
to symmetric stretching vibrations. The methyl rocking wavenumbers are expected in the regions
−
1
-1
[
31] 1100 ± 95 and 1080 ± 80 cm . In our molecule the computed wavenumber at 1164 cm
-1
was assigned to CH rocking mode in CH ; it is also observed at 1168 cm in FTIR spectrum.
3
-1
The peak at 1457 cm in FTIR observed as CH scissoring vibration of the methyl group is
2
-1
correlate well with the computed wavenumber at 1459 cm (mode.no:29) which is evident from
the TED column almost contribute to 30% . The butterfly mode (mode.no:31) of CH is observed
3
-1
-1
at 1422 cm in FT-Raman and also computed at 1429 cm by DFT method. The theoretically
-1
predicted wavenumber at 1445 cm assigned to CH wagging mode (mode.no:30), for this mode
3
the TED contribute to 83%. Klimentova et al. [32] reported the antisymmetric and symmetric O–
−
1
−1
C stretching vibrations in the range, 1214–1196 cm and 1093–1097 cm . In our case the DFT
−
1
−1
calculations give 1253 cm and 1034 cm as symmetric C15─ O18 and O18 ─C19 stretching
−
1
vibrations, respectively. The very weak band observed at 1044 cm (Raman) was assigned as
O18─ C19 stretching vibration.
5
.3.4. N─H vibrations
The N–H stretching vibrations generally give rise to bands at 3500–3300 cm [33, 34].
In the present case, the bands observed at 3320 (B3LYP) assigned as NH stretching vibrations.
−
1
-1
Furthermore the NH stretching frequency is shifted by 52 cm in the IR spectrum with a strong
-1
intensity from the computed value 3320 cm , which indicates the weakening of the NH bond
-1
[
35]. Panicker et al. [36] reported NH deformation bands at 1538, 1220 cm in IR spectrum and
-1
at 1538, and 1223 cm theoretically. In our present study NH inplane bending (δCNH) vibration
-1
is observed at 1172 and 1155 cm (Raman) and computed wavenumbers at 1464, 1328, 1215 and
-1
1
158 cm by B3lyp method, this is good agreement with experimental findings.
5
.3.5. C─N and C═N vibrations
1
0

The C─N stretching vibration [31] coupled with δNH, is moderately to strongly active in
-1
-1
the region 1275 ± 55 cm . El-Shahawy et al. [37] observed a band at 1320 cm in the IR
spectrum as this C-N stretching mode. For the title compound, the C─N stretching modes are
-1
-1
assigned at 1359, 1249 cm by DFT method. It is also observed medium band at 1373 cm and
-1
-1
very strong band at 1250 cm in FTIR and weak band at 1242 cm in FT-Raman spectrum. The
-1
C═N stretching skeletal bands are expected in the range 1672–1566 cm [38]. The band at 1550
-1
cm given by calculation is assigned as C ═ N stretching vibration for the title compound, which
is evident from the assignment column TED almost contribute to 64%. The observed peaks at
-1
-1
8
29, 764, 669 and 592 cm in FTIR spectrum and 699 cm in FT-Raman spectrum identified to
-
δCCN vibrations. The computed wavenumbers gives these vibrations at 831, 757, 695 and 594 cm
1
-1
.
The CCCN torisional (CCCN) bands observed at 918 cm in FTIR spectrum and 920 and 439
-1
-1
cm in FT-Raman spectrum. The calculated wavenumbers at 925, 811, 700, 447 and 418 cm
were assigned CCCN vibrations.
5
.3.6. C═O and N─N vibrations
The carbonyl group is contained in a large number of different classes of compounds, for
which a strong absorption band due to the C═O stretching vibration is observed in the region
-1
[
28] 1850–1550 cm . If a carbonyl group is part of a conjugated system, then the wavenumber of
the carbonyl stretching vibration decreases, the reason being that the double bond character of
the C═O group is less due to the π-electron conjugation being localized. For the title compound,
-1
the υC═O mode is seen as a strong band at 1656 cm in the IR spectrum. The DFT calculations
-1
give this mode at 1679 cm . The δ
in-plane deformation and the out-of-plane deformation
C═O
-1
C═O are expected in the regions 625 ± 70 and 540 ± 80 cm , respectively [31]. In our present
-1
study δC═O vibrations observed at 592 cm in FTIR spectrum. The predicted wavenumbers gives
-1
these modes (mode no’s: 71 & 73) at 527 and 594 cm by DFT method. Also 
vibrations
C═O
-1
-1
identified in weak band at 716 cm in FTIR and at 722 and 639 cm in FT-Raman spectrum.
-
The theoretical calculation gives these modes (mode no’s: 63, 66 & 70) at 811, 720 and 645 cm
1
.
-1
-1
The N─N stretching has been reported at 1115 cm by Crane et al. [39], at 1121 cm by
-1
Bezerra et al. [40] and at 1130 cm by El-Behery and El-Twigry [41]. For our title compound
-1
-1
υN─N vibrations observed at medium intensity band 1066 cm in IR and 1065 cm in Raman
-1
spectrum and also DFT calculation give this band at 1056 cm .
1
1

5
.3.7. O ─H vibrations
The crystallographic data reveals that the hydrogen atoms of NH group is involved in
N─H….O hydrogen bond with neighboring water molecule (H37-O36-H38).The hydrogen atom
H24) of NH participate in hydrogen bonds of the type N9─H24…..O36 . The hydrogen atom
(
H35 of the water molecule participates in hydrogen bond with neighboring oxygen atom (O8) of
the carbonyl group. Additionally, the water molecule (H34-O33-H35) forms hydrogen bond of
type O33-H35….O8. In the title molecule, there are two water molecules, one connected with
the NH and the other to the first through O8 atom with the help of hydrogen bonds as shown in
-1
Fig. 4. The OH stretching appears at 3590–3400 cm in the intramolecular hydrogen bonded
-1
systems [42]. In the present study OH stretching appears at 3372 cm in FTIR and at 3755, 3717,
-1
3
648 and 3548 cm by DFT calculation; these are pure modes, TED almost contributes to 100%.
-1
The H O deformation mode is appears at 1614 and 1621 cm in IR and Raman spectra,
2
-1
respectively [43]. In our case medium band at 1571 cm in FT-Raman spectra and computed
-1
wavenumbers at 1637, 1585 and 1581 cm assigned to H O deformation modes. The rocking
2
-1
mode (mod.no:89) is assigned to the calculated value at 280 cm . The mode (mod.no:70)
-1
corresponding to H O wagging vibration appears at 639 cm in Raman spectrum and it is also
2
-1
calculated at 645,312 and 269 cm by DFT method. The stretching vibration of O─H…..O
-1
hydrogen bonding appears at 142 cm while the N─H…O hydrogen bonding stretching
-1
vibration appears at 128 cm in DFT calculations.
.4. NBO analysis
NBO analysis provides a clear description of the stabilizing inter- actions between filled
donor) and empty (acceptor) orbitals and destabilizing interactions between filled orbitals [44,
5]; it could enhance the analysis of intra- and intermolecular interactions. The energy values for
5
(
4
the interaction between the filled i and vacant orbital j, calculated by the second order
perturbation theory at the B3LYP/6-31G(d,p) level have been tabulated (Table 3). Gaussian
0
3W software [13] with the NBO 3.0 program [18] was used for analysis of the natural orbitals
and their interactions. The result of interaction is a loss of occupancy from the concentrations of
electron NBO of the idealized Lewis structure into an empty non-Lewis orbital. For each donor
(i) and acceptor (j), the stabilization energy E (2) associates with the delocalization i→ j is
estimated as.
F (i, j)2
E  E  q
2
ij
i
 
j
i
1
2

q is the donor orbital occupancy; E , E is the diagonal elements and Fij is the off diagonal NBO
i
i
j
Fock matrix element. Natural bond orbital analysis is used for investigating charge transfer or
conjugative interaction in the molecular system. Some electron donor orbital, acceptor orbital
and the interacting stabilization energy resulted from the second-order micro-disturbance theory
are reported [46, 47]. The larger the E(2) value, the more intensive is the interaction between
electron donors and acceptors. In our MBP3CD∙2H2O molecule, π*(C5-N6) → π*(C1-C2)
*
interaction has 169.4 kJ/mol, π*(C12-C13) → π (C16-C17) interaction has 198.1 kJ/mol and
π*(C14-C15) →π*(C16-C17) interaction has 114.8 kJ/mol and hence they give stronger
stabilization to the structure. Intramolecular hyperconjugative interactions are formed by the
orbital overlap between [σ and π (C–C, C–N, C–H, N–N, N–H) and σ* and π* (C–C, C–N, C–H,
N–N, N–H)] bonding orbitals which results in Intermolecular Charge Transfer (ICT) causing
stabilization of the system. These interactions are observed as an increase in electron density
(ED) in C–C, C–N and N–N antibonding orbital that weakens the respective bond [48]. The
hyperconjugative interaction and electron density transfer from lone electron pair of the O8 atom
to the O33-H35 antibonding orbital in the O33–H35. . .O8 system has been predicted. This
*
hydrogen bonding is formed by the orbital overlap between LP (2) O8 and π (O33-H35) which
consequences intramolecular charge transfer (ICT) causing stabilization of the hydrogen bonded
system. Hence, hydrogen bonding interaction leads to an increase in electron density of O–H
antibonding orbital. Which is evident from the Table 3 energy involved in the hyper conjugative
*
interaction LP (2) O8 → π (O33-H35) is 5.2 KJ /mol. Similarly N9-H24…..O36 hydrogen
bonding is formed by the magnitude of charge transfer from σ (N9-H24) to antibonding orbital
RY*(1) O36 resulting ICT causing stabilization of the hydrogen bonded system. Which is
evident from the table energy involved in the hyperconjugative interaction σ (N9-H24) →
RY*(1) O36 is 1.9 KJ /mol. On the other hand the electron density transfers from lone electron
pair of O36 atom to σ*(N9-H24) antibonding orbital resulting N9-H24…..O36 hydrogen bond is
formed and stabilization energy of this interaction LP (2) O36 → σ*(N9-H24) is 9.9 KJ /mol.
Hence the charge transfer within the unit2 (water molecule: H34-O33-H35) observed from the
interaction LP (2) O33→RY*(2) H 35 and RY*(2) H34 resulting stabilization energy is 1.6 KJ
/
mol and 1.3 KJ /mol respectively. Similarly most important interaction within the unit 3 (water
molecule: H37-O36-H38) is LP (1) O36 → RY*(2) H38 and LP (2) O36 → RY*(2) having the
stabilization energy of about 0.7 KJ /mol and 0.9 KJ /mol respectively.
1
3

5
.5. Static polarizability and first order hyperpolarizability
Quantum chemical calculations have been shown to be useful in the description of the
relationship between the electronic structure of the systems and its NLO response [49]. The
computational approach allows the determination of molecular NLO properties as an inexpensive
way to design molecules by analyzing their potential before synthesis and to determine high-
order hyperpolarizability tensors of molecules.
The static polarizability (α) and the hyper polarizability (β) and the electric dipole
moment (μ) of the MBP3CD∙2H2O are calculated by finite field method using 6-31G(d,p) basis
set. To calculate all the electric dipole moments and the first hyper polarizabilities for the
isolated molecule, the origin of the cartesian coordinate system (x, y, z) = (0, 0, 0) was chosen at
own center of mass of MBP3CD∙2H2O. The NLO activity provide the key functions for
frequency shifting, optical modulation, optical switching and optical logic for the developing
technologies in areas such as communication, signal processing and optical interconnections
[
50,51].
In discussing nonlinear optical properties, the polarization of the molecule by an external
radiation field is often approximated as the creation of an induced dipole moment by an external
electric field. Under the weak polarization condition, we can use a Taylor series expansion in the
electric field components to demonstrate the dipolar interaction with the external radiation
electric field.
The first static hyperpolarizability (βо) and its related properties (β, αо and ∆α) have been
calculated using B3LYP/6-31G(d,p) level based on finite field approach. In the presence of an
applied electric field, the energy of a system is a function of the electric field and the first
hyperpolarizability is a third rank tensor that can be described by a 3×3×3 matrix. The 27
components of the 3D matrix can be reduced to 10 components because of the Kleinman
symmetry [52]. The matrix can be given in the lower tetrahedral format. It is obvious that the
lower part of the 3×3×3 matrices is a tetrahedral. The components of β are defined as the
coefficients in the Taylor series expansion of the energy in the external electric field. When the
external electric field is weak and homogeneous, this expansion is given below:
o
E=E -µ F − 1/2 α F F − 1/6 β F F F
α
α
αβ
α
β
αβγ
α
β
γ+……
1
4

o
Where E is the energy of the unperturbed molecules, F is the field at the origin, μ ,α
αβ
α
α
and βαβγ are the components of dipole moment, polarizability and first hyperpolarizability,
respectively.
The total static dipole moment μ, the mean polarizability α , the anisotropy of the
о
polarizability ∆α and the mean first hyperpolarizability βo, using the x, y and z components are
defined as:
Dipole moment is
2
2
2 1/2
µ = (μ +µ +μ )
x
y
z
Static polarizability is
α = (α +α +α )/3
0
xx
yy
zz
Total polarizability is
-1/2
2
2
2
2
1/2
∆
α = 2 [( α -α ) +( α -α ) +(α -α ) +6α ]
xx yy yy zz zz xx xz
First order hyperpolarizability is
2
2
2
1/2
β = (β +β +β )
x
y
z
Where
βx = (βxxx +βxyy +βxzz)
βy = (βyyy +β + β )
yzz
yxx
βz = (βzzz +βzxx +βzyy
)
2
2
2 1/2
β = [(βxxx + βxyy + β ) + (β +βyzz +β ) + (β +βzxx +β ) ]
xzz
yyy
yxx
zzz
zyy
Since the values of the polarizabilities (α) and hyperpolarizability (β) of the Gaussian 03
output are reported in atomic units (a.u.), the calculated values have been converted into
-24
-33
electrostatic units (esu) (For α: 1a.u. = 0.1482 × 10 esu; For β: 1a.u. = 8.639 ×10 esu). The
-24
mean polarizability α and total polarizability ∆α of our title molecule are 28.0291×10 esu and
о
-24
2
7.7298×10
esu respectively. The total molecular dipole moment and first order
-30
hyperpolarizability are 3.4031 Debye and 2.0236×10 esu, respectively and are depicted in
Table 4. Total dipole moment of MBP3CD∙2H2O molecule is approximately three times greater
than that of urea and first order hyperpolarizability is 6 times greater than that of urea ( µ and β
-30
of urea are 1.3732 Debye and 0.3728×10 esu obtained by HF method [53] ). This result
indicates the good nonlinearity of the title molecule.
5
5
.6. Electronic properties:
.6.1. UV–Vis spectral analysis
1
5

Ultraviolet spectra analysis of MBP3CD∙2H2O has been investigated in gas phase and in
organic solvent DMSO by theoretical calculation. On the basis of fully optimized ground-state
structure, TD-DFT/B3LYP/6-31G (d, p) calculations have been used to determine the low-lying
excited states results listed in Table 5. Experimentally observed UV–vis absorption spectrum of
MBP3CD∙2H2O molecule recorded within 200–800 nm range in DMSO solvent is presented in
Fig. 5. Due to the Frank–Condon principle, the maximum absorption peak (λmax) in an UV–
visible spectrum corresponds to vertical excitation. As can be seen from the Table 5, the
calculated absorption maxima values have been found to be 347.37, 295.86 and 293.54 nm for
gas phase, 344.89, 283.54 and 280.57 nm for DMSO solution at DFT/B3LYP/6-311G(d,p)
method. Experimentally absorption maxima value has been found to be 212.08 nm. The λmax is a
function of substitution, the stronger the donor character of the substitution, the more electrons
pushed into the molecule, the larger λmax. These values may be slightly shifted by solvent effects.
The role of substituents and of the solvent influence on the UV-spectrum. This band may be due
to intramolecular charge transfer transition involving the whole electronic system of the
compound with a considerable charge transfer character originating mainly from the substituted
phenyl moiety and pointing towards the carbonyl group. Calculations of molecular orbital
geometry show that the visible absorption maximum of this molecule corresponds to the electron
transition between frontier orbitals such as translation from HOMO to LUMO (transition of π-
π*).
5
.6.2. Frontier molecular orbitals
Highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital
(
LUMO) are very important parameters for quantum chemistry. We can determine the way the
molecule interacts with other species; hence, they are called the frontier orbitals. Owing to the
interaction between HOMO and LUMO orbital of a structure, transition state transition of π→π*
type is observed with regard to the molecular orbital theory [54]. Therefore, while the energy of
the HOMO is directly related to the ionization potential, LUMO energy is directly related to the
electron affinity. Energy difference between HOMO and LUMO orbital is called as energy gap
that is an important stability for structures [55]. In addition, 3D plots of highest occupied
molecular orbitals (HOMOs) and lowest unoccupied molecular orbitals (LUMOs) are shown in
Fig. 6. According to B3LYP/6-31G(d,p) calculation, the energy band gap (∆E) (translation from
1
6

HOMO to LUMO) of the molecule is about 3.9039 eV. The highest occupied and lowest
unoccupied molecular orbitals are localized mainly on the both rings..
HOMO Energy = -5.4574 eV
LUMO Energy = -1.5535 eV
HOMO–LUMO Energy gap = 3.9039 eV
6
. Natural Population Analysis
The atomic charges of the neutral, cationic and anionic species of MBP3CD∙2H2O
determined by natural population analysis (NPA) using B3LYP/6-31G(d,p) method is presented
in Supplementary material S2. Among the pyridine ring carbon atoms C1 (0.031e), C5
(
0.028e) and C11 (0.047e) of title molecule have positive charges. The positive charge on C1, C5
and C11 is due to the attachment of nitrogen (N6 & N10) atoms to it respectively. Also C7
0.674e) and C15 (0.332e) have the highest positive charge; this is due to the substitution of
oxygen (O8 & O18) atoms respectively. Hydrogen atoms H34 (0.506e), H35 (0.466e), H37
0.501e) and H38 (0.500e) have the highest positive charge when compare to the other hydrogen
(
(
atoms; this is may be due to presence of electronegative oxygen atoms (O33 & O36) of the water
molecules. The oxygen atom O8 (-0.628) has the negative charge, reason for this high negative
charge is (O33─O35….O8) intramolecular hydrogen bonding. Similarly the nitrogen atom N9 (-
0
.453 e) has the high negative charge due the presence of (N9─H24….O36) intramolecular
hydrogen bonding.
7
. Electrostatic potential, Total electron density and Molecular electrostatic potential
Supplementary material S3 shows, the electrostatic potential (ESP), the total electron
density (TED) and Molecular electrostatic potential (MEP) surfaces of the title molecule under
investigation are constructed by using B3LYP/6-31G(d,p) method. The color scheme of ESP
S3.(a) is the negative electrostatic potentials are shown in red (Oxygen atoms) and yellow,
slightly electron rich region (Nitrogen atom) the intensity of which is proportional to the absolute
value of the potential energy, electrostatic while green indicates surface areas where the
potentials are close to zero. Green areas cover parts of the molecule where electrostatic potentials
are close to zero (C–C and C–H bonds). The total electron density of the title molecule computed
at the 0.020000 a.u isodensity surface. The TED plots for title molecule show a uniform
-2
distribution S3.(b). The color code of these maps is in the range between −7.970 e (deepest red)
-2
and + 7.970 e (deepest blue) in compound. The electron rich and partially negative charge of
1
7

the MEP surface is shown in red color, the blue region reveals the electron deficient and partially
positive charge, the slightly electron rich region is indicated by yellow and the green color shows
neutral as shown in S3.(c).
8
. Global reactivity descriptors
The energy gap between HOMO and LUMO is a critical parameter to determine
molecular electrical transport properties. By using HOMO and LUMO energy values for a
molecule, the global chemical reactivity descriptors of molecules such as hardness (η), chemical
potential (μ), softness (S), electronegativity (χ) and electrophilicity index (ω) have been
defined [56,57]. On the basis of EHOMO and ELUMO, these are calculated using the below
equations.
Using Koopman’s theorem [58] for closed-shell molecules,
The hardness of the molecule is
η =
/ 2
The chemical potential of the molecule is
μ =
/ 2
The softness of the molecule is
S = 1/2η
The electro negativity of the molecule is
χ =
/ 2
The electrophilicity index of the molecule is
2
ω = μ /2η
Where A is the ionization potential and I is the electron affinity of the molecule. I and A can be
expressed through HOMO and LUMO orbital energies as I = - EHOMO and A = - ELUMO. The
Ionization potential A and an electron affinity I of our molecule MBP3CD∙2H2O calculated by
B3LYP/ 6-31G (d,p) method is 1.5535 eV and 5.4574 eV respectively. The calculated values of
the Hardness, Softness, Chemical potential, electronegativity and electrophilicity index of our
molecule is 1.9520, 0.2561, -3.5055, 3.5055 and
3.1476 respectively as shown in
supplementary material S4. Considering the chemical hardness, large HOMO-LUMO gap
represent a hard molecule and small HOMO–LUMO gap represent a soft molecule. Energy gap
of the title molecule is large 3.9039 eV so we conclude that our molecule is hard molecule,
1
8

which is evident from supplementary table S4 the chemical hardness is 1.9520 which is greater
than that of chemical softness.
9
. Thermodynamic properties
The temperature dependence of the thermodynamic properties heat capacity at constant
pressure (Cp), entropy (S) and enthalpy change (∆H →T) for MBP3CD∙2H2O was also
0
determined by B3LYP/6-31G(d,p) method in the temperature range 100-1000 K and listed in the
supplementary Table S5. The supplementary material S6 depicts that the entropies, heat
capacities, and enthalpy changes were increasing with temperature due to the fact that the
molecular vibrational intensities increase with temperature [59]. These observed relations of the
thermodynamic functions vs. temperatures were fitted by quadratic formulas, and the
2
corresponding fitting regression factors (R ) are 0.988, 0.959 and 0.981 for heat capacity,
entropy and enthalpy changes respectively. The correlation graphics of temperature dependence
of thermodynamic functions for MBP3CD∙2H2O molecule are shown in Supplementary
material S6. Vibrational zero-point energy of the molecule MBP3CD∙2H2O is 755.66 kJ/mol.
1
0. Conclusion
E)-N′-(4-Methoxybenzylidene) pyridine-3-carbohydrazide dihydrate was synthesized
(
and the structure of the compound was characterized by IR and Raman and UV spectral studies.
The complete molecular optimized geometries of the compounds have been obtained from DFT
calculations with 6-31G (d,p) basis set. The vibrational frequencies of the fundamental modes of
the compound have been precisely assigned and analyzed and the theoretical results were
compared with the experimental vibrations. The difference between the observed and scaled
wavenumber values of most of the fundamentals is very small. Vibrational and NBO analysis
*
confirms the formation of hydrogen bond by the orbital overlap between LP (O8) and π (O33-
H35) which results intramolecular charge transfer (ICT), results in stabilization of the hydrogen
bonded O33–H35. . . . O8 system. Similarly N9-H24…..O36 hydrogen bonding is formed by the
magnitude of charge transfer from σ (N9-H24) to antibonding orbital RY*(1) O36 resulting ICT
causing stabilization of the hydrogen bonded system. The UV spectrum was measured in DMSO
solution and results are compared with theoretical results. The energies of important MO’s and
the λmax of the compound were also determined from TD-DFT method. The calculated first order
-30
hyperpolarizability was found to be 2.0236×10 esu, which is six times greater than reported in
literature for urea. This study also demonstrates that the title compound can be used as a good
1
9

non-linear optical material. Thermodynamic properties in the range from 100 to 1000 K were
0
0
0
obtained. The gradients of C p and S m to the temperature decreases, but that of ΔH m increases,
as the temperature increases.
References
[
[
1] D.S. Chemla, J. Zyss, Nonlinear Optical Properties of Organic Molecules and Crystals,
Academic Press, New York, 1987.
2] P.N. Prasad, D.J. Williams, Introduction to Nonlinear Optical Effects in Organic Molecules
and Polymers, Wiley, New York, 1991.
[
[
[
3] R. Seth, Marder, J.W. Perry, P. William, Schwefer, Science 234 (1989) 626.
4] B. Milton Boaz, S. Jerome Das, J. Cryst. Growth 279 (2005) 383-389.
5] B. Milton Boaz, J. Mary Linet, Babu Varghese, M. Palanichamy, S. Jerome Das, J. Cryst.
Growth 280 (2005) 448-454.
[
6] B. Milton Boaz, P. Santhana Raman, S. Xavier Jesu Raja, S. Jerome Das, Mater. Chem. Phys.
9
3 (2005) 187-193.
[
[
7] Hai-Yun, Z. Chin. J. Struct. Chem. 30, (2011), 724–730.
8] Parashar, B., Punjabi, P. B., Gupta, G. D. & Sharma, V. K. Int. J. Chem. Tech. Res. 1, (2009),
1
022– 1025
9] Havanur, V. C., Badiger, D. S., Ligade, S. G. & Gudasi, K. B. Pharma Chem. 2, (2010), 390
404
10] J. Josephine Novina , G. Vasuki , M. Suresh and M. Syed Ali Padusha Acta Cryst. E69,
2013), o1177– o1178.
.
[
[
[
[
–
(
11] A. Jayarama, H.J. Ravindra, Anthoni Praveen Menezes, S.M. Dharmaprakash, Seik Weng
Ng J. Mol. Struct. 1051 (2013) 285–291.
12] B. Ganapayya, A. Jayarama, Ravish Sankolli , Venkatesha R. Hathwar , S.M.
Dharmaprakash J. Mol. Struct. 1007 (2012) 175–178.
[
13] M. J. Frisch, G.W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb, J. R. Cheeseman, J.
J. A. Montgomery, T. Vreven, K. N. Kudin, J. C. Burant, J. M. Millam, S. S.
Iyengar,J.Tomasi, V. Barone, B. Mennucci, M. Cossi, G. Scalmani, N. Rega, G. A. Petersson,
H.Nakatsuji, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T.
Nakajima,Y. Honda, O. Kitao, H. Nakai, M. Klene, X. Li, J. E. Knox, H. P. Hratchian, J. B.
Cross, V.Bakken, C. Adamo, J. Jaramillo, R. Gomperts, R. E. Stratmann, O. Yazyev, A. J.
2
0

Austin, R.Cammi, C. Pomelli, J. W. Ochterski, P. Y. Ayala, K. Morokuma, G. A. Voth, P.
Salvador, J.J. Dannenberg, V. G. Zakrzewski, S. Dapprich, A. D. Daniels, M. C. Strain, O.
Farkas, D. K.Malick, A. D. Rabuck, K. Raghavachari, J. B. Foresman, J. V. Ortiz, Q. Cui, A.
G. Baboul,S.Clifford, J.Cioslowski, B. B. Stefanov, G. Liu, A. Liashenko, P. Piskorz, I.
Komaromi, R.L.Martin, D. J. Fox, T. Keith, M. A. Al- Laham, C. Y. Peng, A. Nanayakkara,
M.Challacombe, P. M. W. Gill, B. Johnson,W. Chen, M. W. Wong, C. Gonzalez, J. A.
Pople,Gaussian 03, Rev.D02, Gaussian, Inc.: Pittsburgh, PA, 2004.
[
[
[
14] A. D. Becke, J. Chem. Phys. 1993, 98, 5648-5652.
15] C. Lee,W. Yang, R. G. Parr, Phys. Rev. B 1988, 37, 785-789.
16] National Institute of Standards and Technology. Vibrational Frequency Scaling Factors on
the Web. http://srdata.nist.gov/cccbdb/vsf.asp (accessed Sept 24, 2007).
[
[
17] S.M. Islam, S.D. Huelin, M. Dawe, R.A. Poirier J. Chem. Theory Comput., 4 (2008) 86-100.
18] E. D. Glendening, A. E. Reed, J. E. Carpenter, F.Weinhold, NBO Version 3.1, TCI,
University of Wisconsin: Madison, 1998.
[
[
19] M.H. Jamróz, Vibrational Energy Distribution Analysis VEDA 4, Warsaw, 2004
20] D.A. Kleinman, Nonlinear dielectric polarization in optical media, Phys. Rev126 (1962)
1
977–1979.
[
[
[
21] S. Shen, G.A. Guirgis, J.R. Durig, Struct. Chem. 12 (2001) 33-43.
22] D. Michalska, R. Wysoki´nski, Chem. Phys. Lett. 403 (2005) 211-217.
23] D. Michalska, RAINT, A computer program for calculation of Raman intensities from the
Gaussian outputs, Wrocław University of Technology, 2002.
[
[
[
[
[
24] L.E. Sutton, Tables of Interatomic Distances, Chemical Society, London, 1958.
25] Y. Wang, S. Saebo, C.U. Pittman Jr., J. Mol. Struct.: (Theochem.) 281 (1993) 9l–98.
26] G. Varsanyi, Vibrational Spectra of Benzene Derivatives, Academic Press, New York, 1969.
27] A. Fu, D. Du, Z. Zhou, Spectrochim. Acta 59 (2003) 245–253.
28] G. Socrates, Infrared and Raman Characteristic Group Frequencies, third ed., Wiley, New
York, 2001.
[
29] G. Varsanyi, Assignments of Vibrational Spectra of Seven Hundred Benzene Derivatives,
Wiley, New York, 1974.
[
[
30] G. Thilagavathi, M. Arivazhagan, Spectrochim. Acta 79A (2010) 389–395.
31] N.P.G. Roeges, A Guide to the Complete Interpretation of Infrared Spectra of Organic
Structures, Wiley, New York, 1994.
2
1

[
[
[
[
[
[
[
32] J. Klimentova, P. Vojtisek, M. Sklenarova, J. Mol. Struct. 871 (2007) 33–41.
33]L.J. Bellamy, The IR Spectra of Complex Molecules, John Wiley and Sons, New York, 1975.
34] A. Spire, M. Barthes, H. Kallouai, G. De Nunzio, Physics D 137 (2000) 392–401.
35] M. Barthes, G. DeNunzio, G. Ribet, Synth. Met. 76 (1996) 337–340.
36] C.Y. Panicker, H.T. Varghese, T. Tansani, Turk. J. Chem. 33 (2009) 1-14.
37] A.S. El-Shahawy, S.M. Ahmed, N.K. Sayed, Spectrochim. Acta 66A (2007) 143-152.
38] R.M. Silverstein, G.C. Bassler, T.C. Morril, Spectrometric Identification of Organic
Compounds, 5th ed., John Wiley and Sons Inc., Singapore, 1991.
[
[
[
[
39] L.G. Crane, D. Wang, L.M. Sears, B. Heyns, K. Carron, Anal. Chem. 67 (1995) 360.
40] A.C.S. Bezerra, E.L. de Sa, F.C. Nart, J. Phys. Chem. B 101 (1997) 6443.
41] M. El-Behery, H. El-Twigry, Spectrochim. Acta A 66 (2007) 28-36.
42] S. Subashchandrabose, H. Saleem, Y. Erdogdu, O. Dereli, V. Thanikachalam, Jayabharathi,
Spectrochim. Acta A 86 (2012) 231-241.
[
43] V. Arjunan , M. Kalaivani , M.K. Marchewka , S. Mohan , Journal of Molecular Structure
1
045 (2013) 160–170.
[
[
[
44] R. Ditchfield, Mol. Phys. 27 (1974) 789–807.
45] K. Wolinski, J.F. Hinton, P. Pulay, J. Am. Chem. Soc. 112 (1990) 8251–8260.
46] C. James, A. Amal Raj, R. Rehunathan, I. Hubert Joe, V.S. Jayakumar, J. Raman Spectrosc.
3
7 (2006) 1381-1392.
[
[
47] Liu Jun-na, Chen Zhi-rang, Yuan Shen-fang, J. Zhejiag, University Sci. 6B (2005) 584.
48] C. James, G.R. Pettit, O.F. Nielsen, V.S. Jayakumar, I.H. Joe, Spectrochim. Acta 70A (2008)
1
208–1216.
[
[
49] D.M. Burland, R.D. Miller, C.A. Walsh, Chem. Rev. 94 (1994) 31-75.
50] C. Andraud, T. Brotin, C. Garcia, F. Pelle, P. Goldner, B. Bigot, A. Collet, J. Am.Chem.
Soc. 116 (1994) 2094–2101.
[
[
[
[
51] V.M. Geskin, C. Lambert, J.L. Bredas, J. Am. Chem. Soc. 125 (2003) 15651– 15658.
52] D.A. Kleinman, Phys. Rev. 126 (1977) 1962–1979.
53] K. Govindarasu, E. Kavitha, Spectrochim. Acta A, 122 (2014) 130–141.
54] K. Fukui, Theory of Orientation and Stereo Selection, Springer-Verlag, Berlin, 1975 (see
also: K. Fukui, Science 218 (1987) 747).
[
[
55] D.F.V. Lewis, C. Ioannides, D.V. Parke, Xenobiotica 24 (1994) 401.
56] R. Parr, L. Szentpaly, S. Liu, Am. Chem. Soc. 121 (1999) 1922–1924.
2
2

[
[
[
57] P. Chattraj, B. Maiti, U. Sarkar, J. Phys. Chem. A107 (2003) 4973–4975.
58]T. A. Koopmans, Physica 1 (1934) 104-113.
59] Z. Ran, D. Baotong, S. Gang, S. Yuxi, Spectrochim. Acta 75A (2010) 1115–1124.
***********
2
3

i
t
s
)
n
.u
b
a
r
B3lyp/6-31G(d,p)
s
i
t
y
(
n
t
e
Experimental
4000
3500
3000
2500
2000
1500
1000
500
-
Wavenumber (cm )
1
Fig. 1 Comparison of experimental and theoretical B3LYP/6-31G(d,p) FT-IR spectra for
E)-N′-(4-Methoxybenzylidene)pyridine-3-carbohydrazide dihydrate.
(

B3lyp/6-31G (d,p)
i
t
s
)
n
Experimental
3500
3000
2500
2000
1500
1000
500
-
Wavenumber (cm )
1
Fig. 2 Comparison of experimental and theoretical B3LYP/6-31G(d,p) FT-Raman spectra
for (E)-N′-(4-Methoxybenzylidene)pyridine-3-carbohydrazide dihydrate.

-950
-960
-970
-980
-990
(a)
-
-
-
1000
1010
1004
°
0
0
0
50
50
50
100
150
200
250
300
350
350
350
400
400
400
9
N-7C-2C-1C Dihedral angle(°)
-1005
-1006
-1007
-1008
-1009
(
b)
-
-
-
-
-
-
-
-
-
1005.0
1005.5
1006.0
1006.5
1007.0
1007.5
1008.0
1008.5
1009.0
100
150
200
250
300
1
0N-9N-7C-2C Dihedral angle (°)
(
C)
100
150
200
250
300
1
2C-11C-10N-9N Dihedral angle(°)
Fig. 3 Dihedral angle-relative energy curves of (E)-N′-(4-Methoxybenzylidene) pyridine-3-
carbohydrazide dihydrate by B3LYP/6- 31G(d,p) level of theory.

Fig.4 Optimized Molecular structure and atomic numbering of (E)-N′-(4-Methoxybenzylidene)pyridine-3-carbohydrazide
dihydrate

4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
2
12
200
300
400
500
600
700
800
-1
Wavelength (cm )
Fig.5 The UV-visible spectrum (Ethanol) of (E)-N′-(4-Methoxybenzylidene)pyridine-3-
carbohydrazide dihydrate

LUMO Plot
(First excited state)
LUMO Energy = -1.5535 eV
Energy gap = 3.9039 eV
HOMO Energy = - 5.4574 eV
(Ground state)
HUMO Plot
Fig.6 The atomic orbital compositions of the frontier molecular orbital for (E)-N′-(4-
Methoxybenzylidene)pyridine-3-carbohydrazide dehydrate.