Synthesis, structure, spectroscopic studies (FT-IR, FT-Raman and UV), normal coordinate, NBO and NLO analysis of salicylaldehyde p-chlorophenylthiosemicarbazone

Article abstract of DOI:10.1016/j.molstruc.2014.10.024

The thiosemicarbazone compound, salicylaldehyde p-chlorophenylthiosemicarbazone (abbreviated as SCPTSC) was synthesized by refluxing equimolar amounts of 4-(4-methyl phenyl)-3-thiosemicarbazide and salicylaldehyde in presence of one drop of conc. H_2<

Full text of DOI:10.1016/j.molstruc.2014.10.024

Accepted Manuscript
Synthesis, structure, spectroscopic studies (FT-IR, FT-Raman and UV), normal
coordinate, NBO and NLO analysis of salicylaldehyde p-chlorophenyl thiose-
micarbazone
S. Muthu, E. Elamurugu Porchelvi, M. Karabacak, A.M. Asiri, Sushmita S
Swathi
PII:
S0022-2860(14)01037-0
DOI:
http://dx.doi.org/10.1016/j.molstruc.2014.10.024
MOLSTR 21020
Reference:
Journal of Molecular Structure
To appear in:
Received Date:
Revised Date:
Accepted Date:
6 July 2014
11 October 2014
13 October 2014
Please cite this article as: S. Muthu, E. Elamurugu Porchelvi, M. Karabacak, A.M. Asiri, S.S. Swathi, Synthesis,
structure, spectroscopic studies (FT-IR, FT-Raman and UV), normal coordinate, NBO and NLO analysis of
salicylaldehyde p-chlorophenyl thiosemicarbazone, Journal of Molecular Structure (2014), doi: http://dx.doi.org/
10.1016/j.molstruc.2014.10.024
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Synthesis, structure, spectroscopic studies (FT-IR, FT-Raman and UV),
normal coordinate, NBO and NLO analysis of salicylaldehyde p-chlorophenyl
thiosemicarbazone
S. Muthu a*, E. Elamurugu Porchelvi b, M. Karabacak c, A.M. Asiri d,e, Sushmita S Swathif
a Department of Physics, Sri Venkateswara College of Engg, Sriperumbudur-602117, Tamilnadu,
India.
b Department of Physics, Kanchi Pallavan Engineering College, Kanchipram-631502, Tamilnadu,
India.
c Department of Mechatronics Engineering, H.F.T. Technology Faculty, Celal Bayar University,
Turgutlu, Manisa, Turkey
d Department of Chemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
e Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Saudi
Arabia
f Department of Chemical engineering, Sri Venkateswara College of Engg, Sriperumbudur-602117,
Tamilnadu, India.
* Corresponding author, Tel.: 919443690138. Email address: muthu@svce.ac.in ,
mutgee@gmail.com (Dr.S.Muthu)

Abstract
The thiosemicarbazone compound, Salicylaldehyde p-chlorophenylthiosemicarbazone
(abbreviated as SCPTSC) was synthesized by refluxing equimolar amounts of 4-(4-methyl
phenyl)-3-thiosemicarbazide and salicylaldehyde in presence of one drop of conc.H2SO4 in
ethanolic medium for one hour and recrystallised from alcohol. The SCPTSC was characterized
by FT-IR, FT-Raman, UV spectroscopy and thermal analysis. By using density functional theory
(DFT) using B3LYP method with 6-31+G(d,p) and 6-311++G(d,p) basis sets. The molecular
geometry and vibrational frequencies were calculated and compared with the experimental data.
The detailed interpretation of the vibrational spectra has been carried out with aid of normal
coordinate analysis (NCA) following the scaled quantum mechanical force field methodology.
The electronic dipole moment (µD) and the first hyperpolarizability (βtot) values of the
investigated molecule were computed using DFT/B3LYP method with 6-31+G(d,p) and 6-
311++G(d,p) basis sets. The stability and charge delocalization of the title molecule was studied
by natural bond orbital (NBO) analysis. Mulliken population analysis on atomic charges is also
calculated. The molecule orbital contributions were investigated by using the total (TDOS), sum
of α and β electron (αβDOS) density of states. Thermodynamic properties (heat capacity, entropy
and enthalpy) of the title compound at different temperatures are calculated.
Keywords: Thiosemicarbazone compound; FT-IR and FT- Raman spectra; UV spectrum; NCA;
NBO and NLO; αβDOS.

1. Introduction
Thiosemicarbazones (TSCs) are compounds that have been studied for a considerable period of
time for their biological properties. Preparation of transition metal complexes with
thiosemicarbazone (TCS) ligands has been paid considerable attention due to the
pharmacological properties of both ligands and complexes [1,2]. TCS derivatives form an
important class of organic compounds due to their structural chemistry and biological activities,
such as antibacterial, antivirus activities. Heterocyclic sulfur and oxygen containing TCSs have
been the subjects of extensive investigation because of their use for the biological applications
[3,4] TCSs have received great interest because of their bonding modes, biological implications,
structural diversity, and ion-sensing ability [5]. TCS compounds are also applicable in fields of
inorganic chemistry. They are used as a chelating ligand for the formation of metal complexes
because of variety of flexible donor sets of sulfur and nitrogen. TCSs and their metal complexes
are also applicable in the field of material sciences such as nonlinear optical (NLO) [6],
electrochemical sensing [7]. Various TCS derivatives and their metal complexes are notable
materials for their second harmonic generation (SHG) [8]. People are working form last many
years on the synthesis and characterization of transition metal complexes with TCS.
In recent years, among the computational methods calculating the electronic structure of
molecular systems, DFT has been favorite one due to its great accuracy in reproducing the
experimental values in molecule geometry, vibrational frequencies, atomic charges, dipole
moment, thermo dynamical properties, etc. [9-11].
In the present investigation of SCPTSC has been performed using the scaled quantum
mechanical (SQM) force field technique based on DFT calculations. Vibrational spectra of
SCPTSC have been analyzed on the basis of potential energy distribution (PED). The

redistribution of electron density (ED) in various bonding and antibonding orbital’s along with
E(2) energies have been calculated by NBO analysis to give clear evidence of stabilization
originating in the hyperconjugation of hydrogen-bonded interaction. The UV spectroscopic
studies along with HOMO, LUMO analysis have been used to elucidate information regarding
charge transfer within the molecule. By analyzing the total (TDOS) and (αβDOS), the molecular
orbital composition and their contributions to the chemical bonding are studied.
1.
Experimental
The FT-IR spectrum of the sample SCPTSC has been recorded by KBr pellet method in the
region 4000-400 cm-1 using Bruker IFS 66V spectrometer. The FT-Raman spectrum of the
sample was recorded in the range of 4000-100 cm-1 in pure mode using Nd:YAG laser of 200
mw with 4 cm-1 resolution on a BRUKER RFS 100/s . The UV-Vis spectrum has been recorded
using a Perkin Elmer lambda 35 spectrophotometer in the range of 200-1000 nm.All the spectral
measurements are carried out at SAIF, IIT, Chennai, India.
1.1. Preparation of salicylaldehyde p-chlorophenylthiosemicarbazone (SCPTSC)
2.1.1. Preparation of p-chlorophenylthiosemicarbazide
A mixture of p-chloro aniline (0.05 molL-1), 10 mL ammonium hydroxide and 4 mL
carbon disulphide were dissolved in 25 mL ethanol. Mixture of monochloroacetic acid (0.05
molL-1) and sodium hydroxide (0.05 molL-1) is added to the above mixture and shaked well. 10
mL of hydrazine hydrate is added to the above mixture and heated till the volume gets reduced to
half the original volume. The resulting thiosemicarbazide was re-crystallized from water.
(mp=182 0C, yield=75%).
2.1.2. Preparartion of salicylaldehyde p-chlorophenylthiosemicarbazone from p-
chlorophenylthiosemicarbazide
Salicylaldehyde p-chlorophenylthiosemicarbazone was synthesized by refluxing equimolar
amounts of p- chlorophenylthiosemicarbazide and salicyladehyde in presence of one drop of

conc.H2SO4 in ethanolic medium for one hour and re-crystallised from alcohol.(-1960C
,yield=70%). The structure of SCPTSC is shown in Fig. 1.
2.
Computational detail
The molecular structure optimization of the title compound corresponding energy and
vibrational harmonic frequencies are calculated by using the DFT/B3LYP combined with
standard 6-31+G(d,p) and 6-311++G(d,p) basis sets and GAUSSIAN 03W program package
without any constraint on the geometry [12]. In order to fit the theoretical wavenumbers to the
experimental, the scaling factors have been introduced by using a least square optimization of the
computed to the experimental data. Vibrational frequencies are scaled as 0.986 for B3LYP/6-
31+G(d,p) [13] and in the range of wavenumbers above 1700 cm-1 are scaled as 0.958 and below
1700 cm-1 scaled as 0.983 for B3LYP/6-311++G(d,p) [14] to account for systematic errors
caused by basis set incompleteness, neglect of electron correlation and vibrational
anharmonicity. NCA has been performed in order to obtain the detailed interpretation of the
fundamental modes using the MOLVIB program version 7.0 written by Sundius [15]. Natural
co-ordinate as suggested by Pulay et al. [16,17] has been written as input for the MOLVIB
program. The NBO calculations [18] were performed using NBO 3.1 program as implemented in
the Gaussian 03W package at the above said level in order to understand various second order
interaction between the filled orbital of one subsystem and vacant orbital of another subsystem,
which is measure of the intermolecular and intra molecular delocalization or hyper conjugation.
The first hyper polarizabilities and related properties (βtot α, Δα) of title compound SCPTSC
were calculated using B3LYP/6-31+G(d,p) and B3LYP/6-311++G(d,p) basis sets. UV-Vis
Spectra electronic transitions vertical excitation energies, absorbance and oscillator strength were
computed with TD & CIS method. The electronic properties such as HOMO and LUMO
energies are determined by TD-DFT approach. Finally, thermo dynamical functions are
calculated B3LYP/6-31+G(d,p) method.
4.
Results and Discussion
4.1. Structural properties
The molecular structure along with numbering of atoms of SCPTSC is shown in Fig. 1.

The most optimized structural parameters (bond length and bond angle) by B3LYP/6-31+G(d,p)
and B3LYP/6-311++G(d,p) basis sets were shown in Table 1. As the crystal structure of the title
compound is not available as yet, the optimized structure can only be compared with other
similar systems for which the crystal structures have been solved. The calculated values were
compared with the X-ray diffraction results.
It is observed that the calculated C-C bond distances, the C-H and N-H bond lengths are
found to be nearly the same at all levels of calculations. The average bond distances of C-C and
C-H in the benzene ring calculated by DFT method with B3LYP/6-31+G(d,p) and B3LYP/6-
311++G(d,p) basis sets are 1.39 Å and 1.07 Å, respectively. It is very good agreement with
experimental results [19]. The calculated C–N bonds connecting the phenyl rings show excellent
agreement with experimental value.
The C-Cl bond length indicates a considerable increase when substituted in place of C-H.
This has been observed even in benzene derivatives [20-22]. In this study, the C-Cl bond lengths
also are bigger than the C-H ones. The C-Cl bond length by both B3LYP/6-31+G(d,p) and
B3LYP/6-311++G(d,p) basis sets is 1.76 Å. The C-Cl bond length was calculated 1.735-1.744 Å
for similar molecules [20,21]. The bond angles are all well agreed in both the methods. The bond
length value is found to be high for CS bond. In this study, the CS bond length is predicted at
1.68 Å well with experiment values (1.58 Å).
The thermodynamic parameters of the compound, total thermal energy, vibrational energy
contribution to the total energy and the rotational constants values obtained from DFT method
with B3LYP/6-31+G(d,p) and B3LYP/6-311++G(d,p) basis sets are presented in Table 2. The
energy of the compound SCPTSC determined by B3LYP/6-31+G (d,p) and B3LYP/6-
31++G(d,p) basis sets both are equal (-1638 a.u.). However, the zero point vibrational energy is
lower in the DFT/B3LYP method than by other one.
At any given point r(x,y,z) in the vicinity of a molecule, the molecular electrostatic
potential v(r) is defined in terms of the interaction energy between the electrical charge generated
from the molecule electrons, nuclei and positive test charge(a proton) located at r. The molecular
electrostatic potential (MEP) is related to the electronic density and a very useful descriptor for

determining sites for electrophilic attack and nucleophilic reaction as well as hydrogen-bonding
interactions [23]. In the present study, 3D plots of the MEP of SCPTSC are illustrated in Fig. 2.
The different value of electrostatic potential at the surface is represented by different colors.
Potential increases in the order red<orange<yellow<blue. The color code of these maps in the
range between -7.432 eV and +7.432 eV in compound, where blue indicated the strongest
attraction and yellow indicates repulsion. As can seen from the MEP of the title compound while
region having the negative potential are over the electronegative atom (sulfur and chlorine atom),
the region having the positive potential are over the hydrogen atom. From this result, we can say
that the H atom indicates the strongest attraction and Cl and S atom indicate the repulsion. The
contour map of electrostatic potential SCPTSC has been constructed by the DFT/B3LYP/6-
31+G(d,p) method and is shown in Fig. 3. Also confirm the different negative and positive
potential site of the molecule in accordance with the total electron density surface.
4.2. Vibrational analysis
The molecule SCPTSC consists of 32 atoms. Therefore it has 90 normal vibrational modes.
On the basis of CS symmetry the 90 fundamental vibrations of SCPTSC can be distributed as
61A'+29A". The vibrations of the A' species are in-plane and those of the A" species are out-of-
plane. But if the molecule were C1 point group there would not be any relevant distribution A.
FT-IR and FT-Raman spectral wavenumber have been assigned based on the normal
coordinate analysis following the scaled quantum mechanical force field methodology. The PED
for each normal mode among the symmetry coordinates of the molecule were calculated. A
complete assignment of the fundamentals was proposed based on the calculated PED values. The
full set of 119 standard internal valence coordinates was defined in Table 3. From this non-
redundant set of internal coordinates for SCPTSC has been defined in Table 4. Detailed spectral
assignments with PED contributions are given in Table 5. Experimental and simulated spectra
are given in Figs. 4 and 5 for visual comparison. The vibrational assignments for different
functional group have been discussed below.
4.2.1. C-H vibrations
The aromatic C-H stretching vibrations are normally found between 3100-3000 cm-1

[24,25]. In this region, the bands are not affected appreciably by the nature of substituent. The C-
H stretching modes usually appear with strong Raman intensity and are highly polarized. In the
FT-IR and FT-Raman the bands observed at 3290, 3256, 3179, 3138, 3100, 3050, 3000 cm-1 and
3150, 3125, 3110, 3100, 3050, 3025, 3000 2990 cm-1 respectively are assigned to the C-H
stretching vibrations of SCPTSC. The in-plane C-H vibrations normally appear in the range of
1000-1300 cm-1 in the substituted benzenes and out-of plane bending vibrations occur in the
region 750-1000 cm-1 [26,27]. In this study, the C-H in-plane-bending vibrations are assigned to
1206, 1154, 1110, 1077 cm-1 in FT-IR and 1200, 1155, 1130, 1078 cm-1 in FT-Raman. The C-H
out-of-plane bending vibrations are observed at 900, 830, 811, 775, 765, 750 cm-1 in FT-IR and
910, 825, 810, 750 cm-1 in FT-Raman.
4.2.2.C-Cl vibrations
The C-Cl absorption is observed in the broad region between 850 and 550 cm-1 [28,29]. In
this study the C-Cl stretching vibration is observed at 582 cm-1 in FT-IR. This assignment is well
agreed with theoretically calculated C-Cl bond distance of SCPTSC by B3LYP/6-31+G(d,p) and
B3LYP/6-311++G(d,p) methods. Due to longer bond length of C-Cl stretching falls in the lower
frequency region. The C-Cl in-plane bending mode is observed at 240 cm-1 in FT-Raman. These
assignments are good agreement with the literature of N-(chloro substituted phenyl) – 2, 2-
dichloroacetamides, N-substituted aniline and dichloroanilines [28].
4.2.3. Phenyl ring vibrations
The benzene ring posses six stretching vibrations. The carbon-carbon stretching modes of
the phenyl group are expected in the range from 1650 to 1200 cm-1 [30,31]. The actual position
of this mode is determined not so much by the nature of the substituent but by the form of
substitution around the ring [32]. In SCPTSC, the bands appeared at 1650, 1616, 1595, 1563,
1548, 1470, 1458, 1440, 1377, 1330 cm-1 in FT-IR spectrum and 1660, 1615, 1597, 1566, 1489,
1462, 1386, 1340 cm-1 in FT-Raman spectrum is assigned to C-C stretching to the normal
coordinate analysis. These assignments are confirmed by the theoretical observation and PED
calculation. The bands observed at 830 cm-1 in FT-IR spectrum and 825 cm-1 in FT-Raman is
assigned to the CCC in-plane bending modes of the title molecule. In SCPTSC, the CCC in-

plane bending vibration is found at 840 cm-1 and 827 cm-1 at B3LYP/6-31+G(d,p) and B3LYP/6-
311++G(d,p) levels.
4.2.4.C-N, C-S vibrations
The identification of C-N stretching frequencies in the side chain is a rather difficult task,
since there are problems in identifying these frequencies from other vibrations. C-N stretching
usually lies in region 1400-1200 cm-1 [33,34]. In this study, the C-N stretching vibrations of
SCPTSC are identified at 1269, 1242 cm-1 in FT-IR and 1313, 1250 and 1242 cm-1 in FT-Raman
spectrum. The C=N stretching vibrations of SCPTSC are calculated at 1626 cm-1 and observed at
1616 cm-1 in FT-IR. The assignment of C-S stretching vibration in different compounds is
difficult. Both aliphatic and aromatic sulfides have a weak-to-medium band due to C-S stretching
vibration in the region 570-380 cm-1 [35]. In the present study, the band observed at 550 cm-1 in
FT-IR spectrum is assigned to C-S stretching vibration.
4.2.5.NH2 group vibrations
The amino group exhibits scissoring, rocking, twisting, wagging (inversion) and torsional
vibrational modes, in addition to the two sharp stretching modes. In the FT-IR spectrum of the
title compound, 3400 cm-1 and 3350 cm-1 have been assigned to NH2 symmetric asymmetric
stretching vibrations
The observed mode at 1548 cm-1 (FT-IR) has prominent contribution from NH2 scissoring
motion and is in good agreement with calculated wavenumbers. The rocking mode of the amino
group in SCPTSC has been calculated at 1018 cm-1 which is in agreement with the assigned NH2
rocking in the region 1000-1100 cm-1 in literatures [36,37]. This NH2 rocking mode is mixed
with C-C stretching and C-H in-plane bending modes of the phenyl ring. The observed mode at
630 cm-1 (FT-IR) is assigned NH2 twisting motion and is in good agreement with calculated
wavenumbers at 627 cm-1
4.2.6.OH vibrations
The OH group absorbs broadly below 3300 cm-1. In our work, calculated this band at 3676

cm-1 with a contribution of 98% is pure vibration. The band also is observed at 3650 cm-1 in FT-
IR. The O-H in-plane bending vibrations were assigned at 1330 cm-1 in FT-IR experimentally,
which is calculated at 1339 cm-1 (6-311++G(d, p)basis set).
5.
Nonlinear optical effects
Hyperpolarizabilities are very sensitive to the basis sets and level of theoretical approach
employed [38,39], that the electron correlation can change the value of hyperpolarizability. Urea
is one of the prototypical molecules used in the study of the nonlinear optical (NLO) properties
of molecular systems. Therefore it has been used frequently as a threshold value for comparative
purposes. The calculations of the total molecular dipole moment (µD), linear polarizability (α)
and first-order hyperpolarizability (βtot) from the Gaussian output have been explained in detailed
previously and DFT has been extensively used an effective method to investigate the organic
NLO material [40]. The polar properties of the title compound were calculated by DFT/B3LYP
method with 6-31+G(d,p) and 6-311++G(d,p) basis sets using Gaussian 03W program package.
The total molecular dipole moment of SCPTSC from B3LYP with both basis sets are
collected in Table 6. The total molecular dipole moment of SCPTSC from B3LYP/6-31+G(d,p)
and B3LYP/6-311++G(d,p) basis set are 6.249 D and 6.157 D, respectively, which are the four
and half times greater than the value of urea (m=1.3732 D). Similarly the first order
hyperpolarizability of SCPTSC is 2.050x10-30 esu which is 5.5 times greater than the value of
urea (btot=0.372x10-30 esu). Our title molecule with greater dipole moment and
hyperpolarizability value than urea shows that the molecule has large NLO optical property.
6.
Natural bond orbital analysis
NBO analysis provides the most accurate possible ‘natural Lewis structure’ picture of f,
because all orbital details are mathematically chosen to include the highest possible percentage
of the electron density. A useful aspect of the NBO method is that it gives information about
interactions in both filled and virtual orbital spaces that could enhance the analysis of intra- and
intermolecular interactions.
The second order fock matrix was carried out to evaluate the donor-acceptor interactions in

the NBO analysis [41]. The interactions result is a loss of occupancy from the localized NBO of
the idealized Lewis structure into an empty non-Lewis orbital. For each donor (i) and acceptor
(j), the stabilization energy E[2] associated with the delocalization i→j is estimated as
E2 = DEij = qi
Where qi is the donor orbital occupancy,
are diagonal elements and F(i,j) is the off
diagonal NBO Fock matrix element. NBO analysis provides an efficient method for studying
intra- and intermolecular bonding and interaction among bonds and also provides a convenient
basis for investigating charge transfer or conjugative interaction in molecular systems. Some
electron donor orbital, acceptor orbital and the interacting stabilization energy resulting from the
second-order micro-disturbance theory are reported [42].
The larger the E(2) value, the more intensive is the interaction between electron donors and
electron acceptors. Delocalization of electron density between occupied Lewis–type (bond or
lone pair) NBO orbitals and formally unoccupied (anti-bond or Rydberg) non-Lewis NBO orbital
correspond to a stabilizing donor-acceptor interaction. NBO analysis has been performed on the
molecule at the DFT/B3LYP6-31+G(d,p) level in order to elucidate the intramolecular,
delocalization of electron density within the molecule.
In the case of s(C1-C2) orbital the s*(C2-C3), (C2-C8) and (N9-N10) shows stabilization
energy of 4.39, 5.55 and 5.21 kJ/mole. The intramolecular hyperconjugative interaction of s(C1-
C9) distribute to s*(C1-C2) and (N10-C11) resulting to a stabilization of 3.66 and 3.10 kJ/mole.
This enhanced further conjugate with anti-bonding orbital of p*(C2-C8), and (N10-C11) show
stabilization energy of 9.22 kJ/mole and 7.66 kJ/mole, respectively. The p*(C3-C5) bond is
interacting with p*(C2-C8) and p*(C6-C7) with the energies 254.17 kJ/mole and 333.32 kJ/mole.
For SCPTSC, s*(C19-H32), of the NBO conjugated with s*(C1-H21) leads to an enormous
stabilization of 6375.44 kJ/mole as shown in Table 7. This is the highest energy from all
interactions. The calculated atomic charge values from the natural population analysis (NPA)
and Mulliken population analysis (MPA) procedures using the B3LYP with 6-31+G(d,p) basis
set values are listed in Table 8. These two methods (NPA and MPA) predict the same trend that

is the charge distribution shows that the more charge is constructed on N13 (N13=-0.4688 (MPA),
N13=-0.4908(NPA)). Whereas the positive charge reside at hydrogen atoms. Moreover, there is
no difference in charge distribution observed on all hydrogen atoms except the H22, H27, H28
hydrogen atoms. The large positive charge on these hydrogen atoms is due to the large charge
accumulated on the O4 and N13 atoms, respectively. The charge distribution of SCPTSC using
NPA and MPA method is shown in Fig. 6.
7.
UV spectra, HOMO and LUMO analysis
The UV-Vis spectral analysis of SCPTSC have been calculated by TD and CIS methods
along with measured UV-Vis data are summarized in Table 9. The UV-Vis spectra of SCPTSC
are shown in Fig. 7 as measured in water solution. Due to Franck-Condon principle, the
maximum absorption peak (λmax) in a visible spectrum corresponds to vertical excitation. TD-
DFT calculations predict three transitions in the UV-Vis region for SCPTSC molecule. The
strong transitions at 3.474eV (356nm) with an oscillator strength f=0.0002 in gas phase, at
5.1605eV (240nm) with an oscillator strength f=0.0009 in gas phase are assigned to n→p*
transition. The highest occupied molecular orbitals (HOMOs) and Lowest-lying unoccupied
molecular orbitals (LUMO) are very useful for physicists and chemists because the energy
difference between these orbitals (energy gap) represents the minimum energy required to
promote an electron, and is therefore often the most-frequent and important energy transfer
mechanism within a system. The orbitals also provide important electron density information
which can help determine which part of the molecule is most actively participating in an energy
transfer event. The 3D plots of important molecular orbital are shown in Fig. 8. In the present
study we find the energy gap to be 5.7247 eV obtained at TD-DFT method using 6-311++G(d,p)
basis set. The energy value of the HOMO-1, HOMO and LUMO, LUMO+1 were calculated
using B3LYP/6-311++G(d,p) are presented in Table 10. The energy gap between HOMO and
LUMO indicates molecular chemical stability.
The ionization potential is determined from the energy difference between the energy of
the compound derived from electron-transfer (radical cation) and the respective neutral
compound; IP=Ecation -En; IP=-EHOMO while the electron affinity is computed from the energy
difference between the neutral molecule and the anion molecule: EA =En-Eanion ; Ea=-ELOMO
,

respectively. The other important quantities such as electro negativity (χ), hardness (η), softens
(S) and electrophilicity index (ω) were deduced from ionization potential and electron affinity
values [44,45].
Electro negativity (χ) µ ≈ -χ =
Chemical hardness (η) ≈
Softness (S) =
Electrophilicity index (ω) =
The values of electro negativity, chemical hardness, softness and electrophilicity index
were computed using B3LYP/6-311++G (d,p) level of theory and all the above values for the
title compound are collected in Table 10. The dipole moment in a molecule is another important
electronic property. For example, the bigger the dipole moment, the stronger will be the
intermolecular interactions. The calculated dipole moment values for the molecule are also given
in Table 10.
8.
Total, sum of alpha plus beta electrons DOS
In the boundary region, neighboring orbitals may show quasi degenerate energy levels. In
such cases consideration of only the HOMO and LUMO may not yield a realistic description of
frontier orbitals. For this reason, the total (TDOS), sum of α and β electron density of states
[46,47], in terms of Mulliken population analysis were calculated and created by convoluting the
molecular orbital information with Gaussian curves of unit height and full width at half
maximum (FWHM) of 0.3 eV by using the Gauss Sum 2.2 program [48]. The TDOS, αβ DOS of
SCPTSC are plotted in Figs. 9-10. They provide a pictorial representation of MO (molecule
orbital) compositions and their contributions to the chemical bonding. The most important
application of the DOS plots is to demonstrate MO compositions and their contributions to the
chemical bonding through the positive and negative charges provide αβDOS, TDOS diagrams.
The αβDOS shows the bonding, sum of positive and negative electron with nature of the
interaction of two orbitals, atoms or groups. In this case, the title molecule consists of 79 α-

electrons and 79 β-electrons, totally 158 electrons are occupied in density of states. The way
designate a pictorial representation for cat ions and anions is essentially similar to that for neutral
atoms in their ground state. Because of the short range of absorption, alphas are not, in general,
dangerous to life unless the source is ingested or inhaled, in which case they become extremely
dangerous [49]. A positive value of the αβDOS indicates a bonding interaction, negative value
means that there is an anti-bonding interaction and zero value indicates nonbonding interactions
[50].
9.
Thermodynamic properties
On the basis of vibrational analysis and statistical thermodynamics, the standard
thermodynamic functions heat capacity (
) entropy ( ) and enthalpy changes (
) for the
title molecule are obtained from the theoretical harmonic frequencies are listed in Table 11.
From Table 11, it can be observed that these thermodynamic functions are increasing with
temperature ranging from 100 to 1000 K, due to fact that the molecular vibrational intensities
increase with temperature. The correlation equations between heat capacity, entropy, enthalpy
changes and temperatures were fitted by quadratic formulas, and the corresponding fitting factors
(R2) for these thermodynamic properties are 0.9995, 1.0000 and 0.9993, respectively. The
corresponding fitting equations are as follows and the correlation graphics of those shown in Fig.
11. The corresponding fitting equations:
C= 0.7591 + 1.0725T – 0.00054T2
S= 241.85 + 1.0746T – 0.0002T2
H= – 13.886 + 0.1269T + 0.0003T2
(R2= 0.9995)
(R2= 1.0000)
(R2= 0.9993)
These data help to have information for the further study on the SCPTSC. To calculate the
other thermodynamic energies according to relationships of thermodynamic functions and
estimate directions of chemical reactions according to the second law of thermodynamics in
Thermochemical field, the results of thermodynamic calculations can be used.

Conclusion
The complete vibrational spectral analysis and DFT theoretical calculation have been performed
for SCPTSC molecule. The optimized geometric parameters (bond lengths and bond angles) are
theoretically determined compared with the structurally similar molecules. The FT-IR and FT-
Raman spectra of the title molecule are observed with experimental and calculated vibrational
wavenumbers and their PED. The energies of important molecular orbitals and the electronic
absorption wavelengths of the studied molecule are also investigated by TD-DFT method along
with the other electronic and NLO properties. From the hyperpolarizability calculations, we
found that the SCPTSC molecule has non-liner optical response. The strong intramolecular
hyperconjugative interaction of the σ and л electron to the C-C to the C-C anti-bond of the ring
leads to stabilization of the ring as conformed by NBO analysis. The experimental and calculated
results of UV-Vis spectral data were compared. Thermodynamic properties in the range from
100 to 1000 K are obtained. The gradients of
and
increases, as the temperature
increases. The large difference in HOMO and LUMO energy supports the charge - transfer
model of interaction within the molecule. Finally, the theoretical results showed an acceptable
general agreement with experimental record. Thiosemicarbazone compounds are also applicable
in fields of inorganic chemistry. They are used as a chelating ligand for the formation of metal
complexes because of variety of flexible donor sets of sulfur and nitrogen. Thiosemicarbazones
and their metal complexes are also applicable in the field of material sciences such as nonlinear
optical (NLO). Our title molecule with greater dipole moment and hyperpolarizability value than
urea shows that the molecule has large NLO optical property. TSCs are considered to be an
important class of compounds in medicinal chemistry because of their significant antibacterial
antitubercular activity which led a potential area for searching newer anti-tubercular drugs.

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CAPTIONS TO TABLES
Table 1. Optimized parameters for SCPTSC (bond lengths (Å) and bond angles (o).
Table 2. The calculated thermodynamic parameters of SCPTSC employing B3LYP/6-
31+G(d,p) and B3LYP/6-311++G(d,p) methods.
Table 3. Definition of internal coordinates of SCPTSC.
Table 4. Definition of local symmetry coordinates of SCPTSC.
Table 5. Vibrational assignment of SCPTSC by normal coordinate analysis based on SQM
force field calculations.
Table 6. The values of the calculated mD, aO and btotal components for SCPTSC.
Table 7. Second order perturbation theory analysis of fock matrix in NBO basis.
Table 8. Mulliken atomic charges
Table 9. Experimental and calculated absorption wavelength, excitation energies (E), oscillator
strength (f) of SCPTSC by CIS and TD-DFT methods.
Table 10. Calculated energy values of SCPTSC by B3LYP/6-311++G(d,p) method.
Table 11. Thermodynamic properties for SCPTSC obtained by B3LYP/6-31+G(d,p) method.

Table 1. Optimized parameters for SCPTSC (bond lengths (Å) and
bond angles (o).
Parameters
Bond length (Å)
C1-N9
C11-N10
C11-N13
C11-S12
C14-N10
C17-Cl20
C3-O4
Exp.
[19]
B3LYP
6-31+G(d,p)
6-311++G(d,p)
1.26
1.37
1.37
1.58
1.35
1.72
1.36
0.97
1.01
1.10
1.42
1.29
1.44
1.35
1.69
1.46
1.76
1.37
0.97
1.01
1.07
1.39
1.28
1.44
1.35
1.68
1.46
1.76
1.37
0.96
O4-H22
N-H amino average
C-H average
C-C ring average
1.01
1.07
1.39
Bond angle (o)
C14-C19-C18
N10-C14-C19
N10-C14-C15
C19-C14-C15
H28-N13-H27
H28-N13-C11
H27-N13-C11
N13-C11-S12
N13-C11-N10
S12-C11-N10
C14-N10-C11
C14-N10-N9
C11-N10-N9
C1-N9-N10
H22-O4-C3
O4-C3-C2
H21-C1-N9
H21-C1-C2
N9-C1-C2
C-C-C(Ring)
C-C-H (Ring)
122.23
122.14
122.11
115.75
123.31
120.34
116.34
116.07
113.94
129.99
125.14
126.27
108.59
132.66
110.11
117.52
127.13
112.85
120.02
119.03
119.58
122.27
122.10
122.19
115.71
123.44
120.23
116.33
116.10
113.87
130.04
125.08
126.23
108.69
132.80
109.95
117.61
127.23
112.69
120.07
119.12
119.58
120.00
120.00
120.00
118.80
124.30
120.00
124.30
122.00
108.00
124.30
116.50
120.00
123.50
120.00
120.00

Table 2. The calculated thermodynamic parameters of SCPTSC employing B3LYP/6-31+G(d,p)
and B3LYP/6-311++G(d,p) methods.
Thermodynamic parameters
SCF energy (a.u)
B3LYP/6-31+G(d,p) B3LYP/6-311++(d,p)
-1638.57
159.1
-1638.78
158.51
64.44
Total energy (thermal), Etotal(kcal mol-1)
Heat capacity at cont. volume, CV (cal mol-1 K-1)
Entropy, S (cal mol-1 K-1)
Zero point vibrational energy, (joule/mol)
Vibrational energy, Evib (kcal mol-1)
Translational energy (kcal mol-1)
Rotational energy
64.18
128.68
623808
157.32
0.889
130.29
620950
156.73
0.889
0.889
0.889
Rotational constants (GHZ)
A
B
0.3923
0.1468
0.1068
0.3919
0.1476
0.1072
C

Table 3. Definition of internal coordinates of SCPTSC.
I. C. No.
Stretching
1-12
Symbol
Type
Definitions
Ri
C-C
C2-C3, C3-C5, C5-C6, C6-C7, C7-C8, C8-C2, C14-C15, C15-C16, C16-
C17, C17-C18, C18-C19, C19-C14
C1-C2
13
14-17
Ri
Ri
C-C
C-N
C1-N9, C14-N10, C11-N13, C11-N10
18
Ri
Ri
C-S
C11-S12
19-27
C-H
C1-H21, C5-H23, C6-H24, C7-H25, C8-H26, C15-H25, C16-H30, C18-
H31, C19-H32
N13-H27, N13-H28
C3-O4
O4-H22
C17-Cl20
28-29
30
31
Ri
Ri
Ri
Ri
N-H
C-O
O-H
C-Cl
32
In-plane bending
33-38
39-44
βi
βi
Ring 1
Ring 2
C2-C3-C5, C3-C5-C6, C5-C6-C7, C6-C7-C8, C7-C8-C1, C8-C2-C3
C14-C15-C16, C15-C16-C17, C16-C17-C18, C17-C18-C19, C18-C19-C14
, C19-C14-C15
45-60
αi
C-C-H
C3-C5-H23, C6-C5-H23, C5-C6-H24, C7-C6-H24, C6-C7-H25, C8-C7-
H25, C2-C8-H26, C7-C8-H26, C14-C15-H32, C18-C19-H32, C14-C15-
H29, C16-C15-H29, C17-C16-H30, C15-C16-H30, C19-C18-H31, C17-
C18-H31
61-62
63-64
65-66
67
68-70
71
72-73
74-75
76
αi
αi
αi
αi
αi
αi
αi
αi
αi
αi
αi
C-C-C
C-C-Cl
C-N-N
N-C-N
C-C-N
H-N-H
C-C-O
N-C-S
C-O-H
H-C-N
C-N-H
C1-C2-C3, C1-C2-C8
C16-C17-Cl20, C18-C17-Cl20
C1-N9-N10, C14-N10-N9
N10-C11-N13
C2-C1-N9, C19-C14-N10, C15-C14-N10
H27-N3-H28
C2-C3-O4, C5-C3-O4
N10-C11-S12, N13-C11-S12
C3-O4-H22
77
78-79
H21-C1-N9
C11-N13-H27, C11-N13-H28
Out of plane bending
80-89
ωi
H-C-C-C
H21-C1-C2-C3, H21-C1-C2-C8, H23-C5-C6-C3, H24-C6-C7-C5, H25-C7-
C8-C6, H26-C8-C2-C7, H29-C15-C16-C14, H30-C16-C17-C15, H31-C18-
C19-C17, H32-C19-C18-C14
90
ωi
ωi
ωi
ωi
ωi
ωi
ωi
ωi
ωi
C-C-C-C
C-C-O-H
C-N-N-C
O-C-C-C
Cl-C-C-C
N-C-C-C
C-N-C-S
C-N-C-N
N-C-C-H
C1-C2-C3-C8
91-92
93-94
95
96
97
98
99
100-101
C5-C3-O4-H22, C2-C3-O4-H22.
C1-N9-N10-C14, C1-N9-N10-C11
O4-C3-C5-C2
Cl20-C17-C18-C16
N10-C14-C15-C19
C14-N10-C11-S12
C14-N10-C11-N13
N10-C14-C15-H32, N10-C14-C15-H29
Torsion
102-107
ti
ti
ti
Ring 1
C2-C3-C5-C6, C3-C5-C6-C7, C5-C6-C7-C8, C6-C7-C8-C2, C7-C8-C2-C3,
C8-C2-C3-C5
C14-C15-C16-C17, C15-C16-C17-C18, C16-C17-C18-C19, C17-C18-C19-
C14, C18-C19-C14-C15, C19-C14-C15-C16
C11-N13-H27-H28
108-113
Ring 2
114
C-N-H-H
115
116
117-118
ti
ti
ti
N-N-C-S
N-N-C-N
N-C-N-H
N9-N10-C11-S12
N9-N10-C11-N13
N10-C11-N13-H27, N10-C11-N13-H28

Table 4
Definition of local symmetry coordinates of SCPTSC.
No.
Symbol
Definition
stretching
1-12
γCC
γCC
γCN
γCS
R1,R2,R3, R4, R5, R6,R7,R8,R9,R10,R11,R12
13
R13
14-17
18
R14,R15,R16,R17
R18
19-27
28-29
γCH
γNH2ss, γNH2as
R19,R20,R21,R22,R23,R24,R25,R26, R27
R28+R29/ , R28-R29/
30
31
32
γCO
γOH
γCCl
R30
R31
R32
In plane bending
(β33- β34+ β35- β36+ β37- β38 )
(-β33- β34+ 2β35- β36+ β37-β38
(β33- β34+ β36- β37
33
34
35
36
37
38
b trig 1
b asym 1
b sym 1
b trig 2
b asym 2
b sym 2
(β39- β40+ β41- β42+β43- β44
(-β39- β40+2β41- β42- β43-β44
(β39- β40+ β42- β43 )
(α45- α46)/ , (α47- α48)/ , (α49- α50)/
,
(α51- α52)/ , (α53- α54)/ , (α55- α56)/ (α57- α58)/
,
(α59- α60)/
39-46
47
b CCH
b CCC
b CCCl
b CNN
b NCN
b CCN
b HNH
b CCO
(α61- α62)/
(α63- α64)/
48
(α65- α66)/
49
(α67- α68)/
50
(α69- α70)/ , (α71- α72)/
(α73- α74)/
51-52
53
(α73- α74)/
54
(α75- α76)/
55
56
57
b NCS
b COH
b HCN
α77
α78
(α79- α80)/
58
b CNH
Out of plan bending
59-68
69
ω HCCC
ω CCCC
ω CCOH
ꢀ81, ꢀ82, ꢀ83, ꢀ84, ꢀ85, ꢀ86, ꢀ87, ꢀ88, ꢀ89, ꢀ90
η91
70-71
Ψ92, ψ93

72-73
74
ω CNNC
ω OCCC
ω ClCCC
ω NCCC
Φ94, Φ95
γ96
,75
76
Σ97
Σ98
﴾π99- π100
﴿
77
ω CNCS
ω NCCH
Ω101, Ω102
78-79
Torsion
(τ103- τ 104+ τ 105- τ 106+ τ 107- τ 108 ) /
(-τ 103- τ 104+ 2τ 105- τ 106-τ 107+2τ 108) /
(τ 103- τ 104+ τ106- τ 107) /
80
81
82
83
84
τ ring 1
τ asym 1
τsym 1
τ ring 2
τ asym 2
(τ 109- τ 110+ τ 111- τ 112+ τ 113- τ 114) /
(-τ 109- τ 110+ 2τ111- τ112- τ 113+2τ 114) /
(τ 109- τ 110+ τ112- τ 113
)
85
τ sym 2
86
τ (C-NH2)
τ (NNCS)
τ (NNCN)
τ (NCNH)
τ115
87
88
τ116
τ117
89-90
τ118, τ119

Table 5. Vibrational assignment of SCPTSC by normal coordinate analysis based on SQM force field calculations.
Experimental
wavenumber
FT-IR FT-Raman
Calculated wavenumber(scaled) B3LYP/6-31+G(d,p) B3LYP/6-311++G(d,p)
b
c
b
c
No
1
2
3
4
5
6
7
8
6-31+G(d,p)a 6-311++G(d,p)a
IIR
IRaman
7
IIR
IRaman
6
Vibrational assignments d (%PED)
νOH(98)
νasNH2(98)
νssNH2(96)
νCH(100)
νCH(98)
νCH(99)
νCH(96)
νCH(98)
νCH(97)
νCH(96)
νCH(95)
νCH(98)
νCC(94)
νCN(98)
νCC(80), νCO(9)
νCC(97)
ρNH2(80)
3650
3400
3350
3290
3256
3179
3138
3100
-
3050
3000
-
1650
1616
1595
1563
1548
-
-
-
-
-
3778
3698
3549
3357
3241
3218
3182
3171
3168
3165
3151
3126
1666
1626
1616
1608
1590
1536
1514
1511
1474
1446
1407
1353
1347
1324
1316
1305
1262
1256
1235
1211
3676
3576
3437
3245
3128
3112
3074
3064
3061
3058
3045
3021
1644
1607
1596
1591
1574
1521
1501
1495
1459
1432
1392
1339
1328
1310
1299
1292
1247
1246
1225
1201
22
38
21
1
23
37
21
0
3
8
2
3
8
2
3150
3125
3110
3100
3050
3025
3000
2990
1660
-
4
24
3
0
1
4
1
4
12
3
0
5
0
61
62
1
24
5
6
26
9
22
3
34
23
100
27
6
1
6
4
3
5
10
4
4
23
2
0
1
4
1
3
12
2
0
5
0
57
62
1
23
4
8
30
8
16
17
28
15
100
20
4
1
6
4
3
5
10
4
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
5
5
77
100
14
11
1
1
7
8
9
5
3
2
1
1
1
3
28
2
68
100
15
16
1
1
7
9
9
5
3
2
1
2
0
2
1615
-
1597
1566
1489
1462
-
νCC(84), νCN(11)
νCC(95)
νCC(97)
1470
1458
-
νCC(98)
1440
1377
1330
-
1312
-
1269
1242
-
1206
-
-
νCC(80), bCCH(10)
νCC(70), νCO(19)
bOH(75), νCC(15)
νCC(64), νCO(30)
νCO(60), νCC(21)
νCN(75), νCO(11), bCCH(10)
νCN(65), bCCH(19)
νCN(58), νCC(32)
νCN(46), bR2 sym d(22)
bCCH(60), bR1 sym d(25), bR2 sym d(18)
bCCH(90)
1388
-
1340
1320
1313
-
1250
1242
1200
-
15
15
1
2
4
3

33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
1154
-
-
1155
-
-
1130
-
1078
1033
1009
1000
980
960
943
-
1171
1169
1167
1152
1113
1100
1052
1018
1015
997
971
970
936
922
889
874
844
840
825
820
752
748
737
719
684
664
637
627
607
583
563
546
520
508
502
474
470
440
394
382
1163
1159
1156
1143
1103
1093
1044
1007
1004
993
960
956
924
913
881
867
842
827
815
814
745
740
732
717
683
661
634
624
604
579
560
541
517
506
497
470
467
437
389
376
24
11
9
6
17
6
1
15
33
8
0
0
1
0
4
9
11
1
8
1
1
21
5
0
0
3
1
0
0
5
8
0
3
14
4
4
13
0
2
4
3
0
3
4
5
1
0
0
0
0
0
2
1
0
0
3
0
0
1
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
11
9
27
6
17
4
1
4
45
9
0
0
1
0
4
11
11
1
8
1
0
21
5
0
1
3
1
0
0
5
8
0
3
14
4
4
8
2
2
2
13
4
3
0
3
1
8
1
0
0
0
0
0
2
1
0
0
4
0
0
1
0
0
0
0
0
0
1
0
0
0
0
0
0
1
0
0
0
bCCH(77)
bCCH(62), bR1 sym d(32)
bCCH(71), bR2 sym d(22)
bCCH(89), ωHCCC(6)
-
1110
1077
1033
1010
-
985
-
959
-
bCCH(45), νCC(28), bR1 sym d(12)
bCCH(67), bR1 sym d(25)
bR1 sym d(45), bCCH(35)
rNH2(51), bR1 trig d(32)
bR2 trig d(49), bR1 trig d(19)
bR2 trig d(65), bR2 asym d(21)
bR1 asym d(54), bCCH(38)
bR2 asym d(62), ωHCCC(26)
ωHCCC(37), bR1 asym d(27)
ωHCCC(29), bCCC(28)
ωHCCC(41), bR2 asym d(34)
ωHCCC(48), bCCC(25)
ωHCCC(60), τR1 sym d(17)
bCCC(68), ωHCCC(15)
ωHCCC(59), τR2 sym d(11)
ωHCCC(69), τR1 sym d(29)
ωHCCC(45), τR1 asym d(27)
ωHCCC(40), bCCO(25)
ωHCCC(49), τR1 asym d(18), bCOH(15)
τR1sym d(52), bCOH(15), τR2asymd(14)
τR2sym d(44), ωCCCC(25)
bCCO(71), bCOH(18)
bCOH(69), bCCO(21)
tNH2(45), bCCN(27)
τR2trig d(34), τR1trig d(32)
νCCl(60), bCCN(31)
bCCN(51), γCS(30)
νCS(70), τR1 asym d(19)
τ R1 asym d(39), bCCN(31)
τ R2 asym d(42), bCNN(24)
bCCN(62), νCCl(20)
ωCCCC(41), τR1 asym d(38)
bCNN(59), νCCl(30)
τNNCS(24), bHNH(19)
bCNH(32), ωCCCCl(13)
bHNH(47), bNCS(22)
900
-
-
910
-
-
-
-
830
-
825
-
810
811
775
765
750
-
680
657
-
630
611
582
567
550
-
-
750
-
710
-
660
640
-
600
-
570
-
-
-
-
494
478
460
-
-
-
499
-
470
450
-
8
2
2
2
1
1
-

73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
327
326
315
304
294
267
238
208
200
167
132
128
109
97
325
316
302
295
265
258
230
207
199
163
131
125
112
93
38
0
10
1
18
0
0
1
0
0
0
1
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
29
1
3
0
29
1
1
0
1
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
ωCCCC(33), bNCS(26)
bNCN(44), τ C-NH2(21)
bNCS(39), ωCCCCl(11)
bHCN(59), ωCCCCl(22)
-
307
-
271
240
210
-
163
132
-
-
-
85
-
-
ωCCCCl(53), τHCNH(16)
τHCNH(46), bNCS(19), ωCCCO(13)
bCCCl(59), ωCNNC(13), τC-NH2(11)
ωCCOH(43), τNCNH(26), ωCNNC(12)
ωCCOH(43), ωCCCCl(28)
ωOCCC(63), ωNCCCl(10)
ωCNNC(29), τNNCS(26)
ωCNNC(41), τC-NH2(21)
τ NCNH(51), ωOCCC(22)
τNCNH(55), ωCNCS(17)
ωCNCS(47), τC-NH2(11)
τC-NH2(61), ωNCCC(27)
ωNCCC(37), τNCNH(16)
ωNCCC(40), ωCNCS(10)
86
61
48
18
85
63
47
22
-
a scaling factor 0.986 for B3LYP/6-31+G(d,p) and 0.983 (for wavenumber under 1700 cm-1) and 0.958 (for those over 1700 cm-1) for B3LYP/6-311++G(d,p)
b relative absorption intensities normalized with highest peak absorption equal to 100.
c relative Raman intensities normalized to 100.
d n; stretching, ss; symmetric stretching, as; asymmetric stretching, b; in plane bending, ω; out of plane bending, ρ; scissoring, r; rocking, t; twisting, τ; torsion, R; Ring,
sym d; symmetric deformation, asym d; asymmetric deformation, trig d; trigonal deformation. 6-31+G(d,p) basis set was used to obtain the PEDs.

Table 6. The values of the calculated mD, aO and btotal components for
SCPTSC.
parameters B3LYP/6-31+G(d,p)
B3LYP/6-311++G(d,p)
5.714
5.797
-2.316
mx
my
-2.276
0.281
0.282
mz
6.249
6.157
mD
342.623
-21.844
303.588
0
344.314
-21.841
303.536
0
axx
axy
ayy
axz
0
0
ayz
110.657
3.739x10-23
9.355x10-23
1346.07
-614.22
446.86
1991.15
0.1732
-0.0278
0.2657
80.721
124.28
0.000605
2.050x10-30
111.081
3.749x10-23
9.391x10-23
1364.61
-614.22
446.86
azz
aO (esu)
Da (esu)
bxxx
bxxy
bxyy
byyy
bxxz
bxyz
byyz
bxzz
byzz
bzzz
btotal (esu)
1991.15
0.1732
-0.0278
0.2657
80.72
124.28
0.000605
2.0865x10-30

Table 7. Second order perturbation theory analysis of fock matrix in NBO basis.
Donar (i) Type
ED/e Acceptor(i)
1.9608 C2-C3
C2-C8
N9-N10
1.9844 C1-C2
N10-C11
Type
σ*
σ*
σ*
σ*
σ*
π*
π*
ED/e E(2)a(kjmol-1) E(j)-E(i)b(a.u.) F(i,j)c(a.u.)
C1-C2
σ
0.0382
0.0342
0.0394
0.0342
0.0734
0.4028
0.7161
0.2404
4.39
5.55
5.21
3.66
3.10
9.22
7.66
21.55
1.39
1.40
1.38
1.60
1.34
0.40
0.26
1.38
0.070
0.079
0.059
0.069
0.056
0.059
0.049
0.155
C1-C9
σ
π
σ
σ
π
σ
π
1.9187 C2-C8
N10-C11
C1-H21
C1-H21
C2-C8
1.7896
σ*
σ*
σ*
C19-H32
1.9575 C1-C2
C2-C3
1.6153 C1-N9
C3-C5
1.9744 C2-C3
C5-C6
1.6475 C2-C8
C6-C7
1.9607 N10-C14
1.8155 C14-C19
1.9607 C16-C17
C17-Cl20
1.6487 C14-C19
C17-C18
1.7407 C1-H21
C19-H32
1.9745 C3-C5
1.8849 C3-C5
1.9396 N10-C11
C15-H29
1.6952 N10-C11
C15-H29
0.3831 C2-C8
C6-C7
0.4391 C15-C16
0.1856 C1-H21
0.0088
0.0342
188.40
5.88
1.36
1.40
0.154
0.087
σ*
π*
π*
σ*
σ*
π*
π*
σ*
π*
σ*
σ*
π*
π*
σ*
σ*
σ*
π*
σ*
σ*
π*
π*
π*
π*
π*
σ*
0.0382
0.2436
0.3831
0.0382
0.0192
0.4028
0.3570
0.0473
0.4391
0.0358
0.0470
0.4391
0.3875
0.2404
0.1856
0.0278
0.3831
0.0734
0.2020
0.0734
0.2020
0.4028
0.3570
0.2981
0.2404
3.85
26.24
27.72
5.95
1.40
0.28
0.30
1.41
1.41
0.33
0.33
1.37
0.41
1.37
0.90
0.29
0.29
1.33
1.37
1.21
0.38
1.00
1.14
0.64
0.77
0.02
0.01
0.02
0.02
0.060
0.079
0.081
0.082
0.069
0.072
0.079
0.060
0.089
0.071
0.066
0.077
0.073
0.535
0.189
0.078
0.096
0.084
0.140
0.064
0.304
0.094
0.091
0.094
0.746
C3-C5
4.22
19.07
24.05
3.24
20.96
4.61
N10-C11
C15-C16
σ
π
σ
6.04
π
σ
24.55
22.89
267.41
32.91
6.38
26.41
8.71
19.96
7.15
142.08
254.17
333.22
172.30
6375.44
C19-H32
LP(1)O4
LP(2)O4
LP(1)S12
σ
π
σ
LP(2)S12
C3-C5
π*
π*
C14-C19
C19-H32
π
σ*
a E(2) means energy of hyper conjugative interaction (stabilization energy)
b Energy difference donor and acceptor i and j NBO orbitals.
c F(i.j) is the fork matrix element between i and j NBO orbitals.