Experimental and theoretical studies of (FTIR, FT-NMR, UV-Visible, X-ray and DFT) 2-(4-Allyl-5-pyridin-4-yl-4H-[1,2,4]triazol-3-ylsulfanyl)-1-(3-methyl- 3-phenyl-cyclobutyl)-ethanone

Article abstract of DOI:10.1016/j.molstruc.2014.01.077

The single crystal structure, 2-(4-Allyl-5-pyridin-4-yl-4H-[1,2,4]triazol- 3-ylsulfanyl)-1-(3-methyl-3-phenyl-cyclobutyl)-ethanone, has been synthesized and characterized by IR, NMR, UV spectra and X-ray diffraction methods. In addition, the optimized str

Full text of DOI:10.1016/j.molstruc.2014.01.077

Journal of Molecular Structure 1065-1066 (2014) 1–9
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstruc
Experimental and theoretical studies of (FTIR, FT-NMR, UV–Visible,
X-ray and DFT) 2-(4-Allyl-5-pyridin-4-yl-4H-[1,2,4]triazol-3-ylsulfanyl)-
1-(3-methyl-3-phenyl-cyclobutyl)-ethanone
b
Çig˘dem Yüksektepe Ataol a, , Öner Ekici
⇑
a Department of Physics, Faculty of Science, Cankiri Karatekin University, 18100 Ballica, Cankiri, Turkey
b Department of Chemistry, Faculty of Science, Fırat University, 23119 Elazıg˘, Turkey
h i g h l i g h t s
ꢀ
ꢀ
ꢀ
Theoretical modeling of the C23H24N4OS, in comparison to the experimental.
The single crystal structure of the prepared compound has been investigated by different spectroscopic techniques.
The crystal and the optimized molecular structures are characterized, and discussed.
a r t i c l e i n f o
a b s t r a c t
Article history:
The single crystal structure, 2-(4-Allyl-5-pyridin-4-yl-4H-[1,2,4]triazol-3-ylsulfanyl)-1-(3-methyl-3-phe-
nyl-cyclobutyl)-ethanone, has been synthesized and characterized by IR, NMR, UV spectra and X-ray dif-
fraction methods. In addition, the optimized structure, the vibrational assignments, the chemical shifts,
the molecular orbital energies, molecular electrostatic potential maps and thermodynamic properties,
ionization potential, electron affinity, electronegativity, global chemical hardness and chemical softness
of the molecule have been investigated by using Density Functional Theory with B3LYP/6-31G(d) and
B3LYP/6-311G(d, p) basis sets. UV–Visible spectrum of the compound was recorded and the electronic
properties HOMO and LUMO energies were measured by time-dependent TD-DFT approach. The
observed results of the compound have been compared with theoretical results and it is found that
the experimental data show good agreement with calculated values. The single crystal structure of the
compound crystallizes in the monoclinic system with space group C 2/c.
Received 14 November 2013
Received in revised form 23 January 2014
Accepted 23 January 2014
Available online 20 February 2014
Keywords:
Pyridin
Triazole
Single crystal
Density Functional Theory
Vibrational assignment
Ó 2014 Elsevier B.V. All rights reserved.
1. Introduction
successfully behave as not only the extended exo-bidentate linkers
with the terminal pyridyl groups but also as the promoter of a
Compounds containing triazole subunits have been intensively
studied owing to their diverse biological properties and also be-
cause of the ease of complexation [1–3]. 1,2,4-Triazole and its
derivatives are an important class of ligands used as building tec-
tons in constructing coordination complexes [4–6]. In particular,
pyridyl-decorated triazole ligands are extensively studied, for
example R-Isophthalate (R = AH, ANO2, and ACOOH) as modular
building blocks for mixed-ligand coordination polymers incorpo-
rated with a versatile connector 4-amino-3,5-bis(3-pyridyl)-1,2,4-
triazole 4-amino-3,5-bis(3-pyridyl)-4H-1,2,4-triazole, [7] and
other groups [8,9]. In the published articles, such series of ligands
coordinative cycle with the central triazole upon metalation [9].
1,2,4-Triazoles and their derivatives are found to be associated
with various biological activities such as anticonvulsant, anti-
fungal, anticancer, antiinflammatory and antibacterial properties.
Several compounds containing 1,2,4-Triazole rings are well known
as drugs. For example, fluconazole is used as an antimicrobial drug,
while vorozole, letrozole and anastrozole are non-steroidal drugs
used for the treatment of cancer and loreclezole is used as an
anticonvulsant [10]. The crystal structure of 2-(4-Allyl-5-pyridin-
4-yl-4H-[1,2,4]triazol-3-ylsulfanyl)-1-(3-methyl-3-phenyl-cyclo-
butyl)-ethanone is based on simple reaction between RSH and
R0CH2Cl. In chemistry literature there are some example showing
reactivity of between 4-(prop-2-en-1-yl)-5-(pyridin-4-yl)-4H-
1,2,4-triazole-3-thioland2-chloro-1-(3-methyl-3-phenylcyclobutyl)
ethanone [11–17].
⇑
Corresponding author. Tel.: +90 376 2181123; fax: +90 376 2181031.
E-mail
addresses:
yuksektepe.c@karatekin.edu.tr,
yuksekc@yahoo.com
(Ç.Y. Ataol).
http://dx.doi.org/10.1016/j.molstruc.2014.01.077
0022-2860/Ó 2014 Elsevier B.V. All rights reserved.

2
Ç.Y. Ataol, Ö. Ekici / Journal of Molecular Structure 1065-1066 (2014) 1–9
Table 1
Crystallographic data of (1).
In this work, we report the experimental and the theoretical
studies of single crystal structure (C23H24N4OS) and also, in the fol-
lowing we discuss IR, NMR, UV spectra of compound by using Den-
sity Functional Theory (DFT) calculations. The results calculated in
all these methods were compared with the experimental results
which yield good agreement between observed and calculated
values.
Empirical formula
Molecular weight
Temperature, T (K)
Wavelength (Å)
Crystal system
Crystal size (mm3)
Space group
a (Å)
C23H24N4OS
404.53
296
0.71073
Monoclinic
0.720 ꢂ 0.530 ꢂ 0.340
C 2/c
36.1594(14)
5.7537(2)
2. Experimental
b (Å)
c (Å)
33.1187(12)
2.1. General
a
(°)
b (°)
(°)
90
142.261(16)
90
4217.3(3)
8
0.9901, 0.9955
1.425
1.84–27.22
c
IR spectrum was recorded on an ATI Unicam-Mattson 1000 FTIR
spectrophotometer using KBr pellets. 1H NMR and 13C NMR spectra
were obtained by using a Bruker 300 MHz spectrometer. The UV
spectrum of the compound was recorded on a Schimadzu UV-
1700 spectrometer in CHCl3 solvent.
Volume, V (Å3)
Z
Tmin, Tmax
Calculated density (Mg mꢁ3
h Range (°)
)
Index ranges
Measured reflections
Independent reflections
h = ꢁ42 ? 42, k = ꢁ6 ? 6, l = ꢁ38 ? 37
25,264
3711
2.2. Synthesis of the title compound
Observed reflections (I > 2
r
)
3044
1.057
Goodness-of-fit on F2
The compound was synthesized as shown in Scheme 1 by the
following procedure. To a stirred solution of 4-allyl-5-(pyridine-
4-yl)-4H-1,2,4-triazole-3-thiol (10 mmol) and potassium carbonate
(10 mmol) in 30 mL of absolute ethanol, 2-chloro-1-(3-methyl-3-
phenylcyclobutyl) ethanone (10 mmol) in 10 mL of absolute ethanol
was added dropwise and stirring was continued for 2 h. more at
room temperature. The solvent was evaporated in vacuo to dryness.
Residue was triturated with water and filtered. Suitable single
crystals for crystal structure determination were obtained by slow
evaporation of its ethanol solution. Yield: 88%, melting point:
R1 indice (I > 2
wR2 indice (I > 2
qmax (e/Å3)
r
)
r
0.0472
0.1308
ꢁ0.119, 0.103
)
D
qmin, D
Fourier map and refined anisotropically. The all hydrogen atoms
were included using a riding model and refined isotropically with
CH = 0.93 Å (for phenyl group), CH2 = 0.97 Å, CH3 = 0.96 Å and
CH = 0.98 Å Uiso(H) = 1.2 Ueq (1.5 for methyl group). Relevant crys-
tal data and details of the structure determinations are given in
Table 1.
366 K. Characteristic IR bands: 3095–3018 cmꢁ1
2973–2864 cmꢁ1 (aliphatics), 1708 cmꢁ1 (C@O), 1650 cmꢁ1
(C@N pyridine), 1606 cmꢁ1
(C@N triazole or C@C alken). Charac-
m(aromatics),
m
m
m
m
teristic 1H NMR shifts (CDCl3, d, ppm): 1.46 (s, 3H, ACH3 in cyclobu-
tane), 2.28–2.33 (m, 2H, ACH2A in cyclobutane), 2.43–2.50 (m, 2H,
ACH2A in cyclobutane), 3.737 (q, J = 8.78 Hz, 1H, ˜CAH in cyclobu-
tane), 4.34 (s, 2H, SACH2A), 4.73 (t, J = 2.2 Hz, 2H, ANACH2A), 4.86
(d, J = 17.2 Hz, 1H, HAH@CA, on ethylene group), 5.25 (d, J = 10.6 Hz,
1H, HBH@CA, on ethylene group), 5.90–6.01 (m, 1H, AHC@CH2A, on
ethylene group), 7.12–7.18 (m, 3H, aromatics), 7.28–7.32 (m, 2H,
aromatics), 7.65 (d, J = 1.6 Hz, 2H, C@CH aromatics on pyridine ring),
8.75 (d, J = 1.5 Hz, 2H, N@CH aromatics on pyridine ring). Character-
istic 13C NMR shifts (CDCl3, d, ppm): 204.13, 153.69, 152.64, 150.85,
150.63, 134.37, 130.92, 128.32, 125.67, 124.56, 122.11, 118.66,
47.05, 41.27, 39.08, 38.47, 36.69, 30.36.
2.4. Computational methodology
The molecular structures of the title compound in the ground
state (in vacuo) were optimized by DFT methods to include corre-
lation corrections with the 6-31G(d) and 6-311G(d, p) basis sets. In
DFT calculations, hybrid functionals are also used, including the
Becke’s three-parameter functional (B3) [21], which defines the ex-
change functional as the linear combination of Hartree–Fock, local,
and gradient-corrected exchange terms. The B3 hybrid functional
was used in combination with the correlation functionals of Lee
et al. [22].
Then vibrational frequencies for optimized molecular structures
have been calculated. The geometry of the title compounds, to-
gether with that of tetramethylsilane (TMS) is fully optimized. 1H
and 13C NMR chemical shifts are calculated within GIAO approach
[23,24] applying B3LYP method with 6-31G(d) and 6-311G(d, p)
basis sets. The isotropic shielding values were used to calculate
the isotropic chemical shifts d with respect to tetramethylsilane
2.3. Single crystal XRD
The data collection was performed at 293 K on a Stoe-IPDS-2
image plate detector using a graphite monochromated Mo Ka radi-
0
ation (k = 0.71073 ÅA). Data collection and cell refinement were per-
formed using X-AREA [18] and X-RED32 [18]. The structure was
solved by direct methods using SHELXS-97 [19] and refined by a
full-matrix least-squares procedure using the program SHELXL-
97 [19]. Molecular graphics were performed using ORTEP-3 [20].
All non-hydrogen atoms were easily found from the difference
(TMS). diso(X) =
r
TMS(X) ꢁ
riso(X), where diso is isotropic chemical
shift and riso is isotropic shielding. UV–Visible spectra, electronic
transitions, vertical excitation energies and oscillator strengths
were computed with the time dependent (TD) DFT method. Be-
sides of these, the lowest unoccupied molecular orbital (LUMO)
N
N
N
N
O
C
N
Acetone
O
C
+
K2CO3
SH
+
N
S CH2
N
CH3
CH2 Cl
N
H2C
HC
H3C
H2C
HC
CH2
CH2
Scheme 1. Synthetic route for the synthesis of the target compound.

Ç.Y. Ataol, Ö. Ekici / Journal of Molecular Structure 1065-1066 (2014) 1–9
3
Table 2
highest occupied molecular orbital (HOMO) energy differences for
these species were calculated with this method. All the calcula-
tions were performed using the Gaussview molecular visualization
program [25] and Gaussian 03 program on a personal computer
[26].
Selected geometrical parameters of the title compound (1) with X-ray structure and
DFT method.
Experimental B3LYP 6-
31G(d)
B3LYP 6-311G(d, p)
Bond lengths (Å)
O1AC12
C11AC12
S1AC11
S1AC7
N1AC3
N1AC4
N2AC6
N2AC7
N2AC8
N3AC6
N3AN4
N4AC7
The molecular electrostatic potential (MEP) was evaluated to
research the reactive sites of the title compound using B3LYP/6-
311G(d, p) level. In addition, electronic absorption spectra were
calculated using the time-dependent DFT (TD-DFT) method.
1.213(3)
1.507(3)
1.803(2)
1.749(2)
1.331(4)
1.327(3)
1.361(3)
1.371(3)
1.473(3)
1.315(3)
1.381(3)
1.301(3)
1.216
1.531
1.830
1.766
1.337
1.341
1.379
1.376
1.463
1.323
1.369
1.317
1.210
1.528
1.829
1.766
1.335
1.339
1.378
1.376
1.463
1.319
1.366
1.312
3. Results and discussion
3.1. Description of the crystal structure using XRD
The single crystal structure is shown in Fig. 1. The title com-
pound (1) crystallizes in the monoclinic space group C 2/c with
eight molecules in the unit cell but the asymmetric unit in the
crystal structure contains only one.
The crystal structure (C23H24N4OS) contains pyridine, triazole,
phenyl and cyclobutane rings. The pyridine, triazole and phenyl
rings are planar with maximum deviations of ꢁ0.0051(17),
0.0074(13) and ꢁ0.0042(16) Å, respectively. The dihedral angles
between the pyridine ring A(N1/C1AC5), the triazole ring
B(N2AN4/C6AC7), the cyclobutane ring C(C13AC16) and
D(C18AC23) are 44.15(11)° A/B, 83.23(12)° A/C, 62.72(09)° A/D,
53.40(13)° B/C, 26.05(12)° B/D and 36.25(15)° C/D.
In the cyclobutane ring C, the dihedral angle between
C14AC15AC16 plane and C14AC13AC16 plane is 25.91(44)°. The
value found in this study is in agreement with literature values
such as 24.02(22)° [27], 25.74(15)° [13] and 24.3° [28]. As can be
seen in Table 2, in the triazole ring, due to conjugations of elec-
trons, the N3AN4 single bond length is shorter than reported val-
ues [29,30]. The crystal structure exhibits intra–inter molecular
interactions. In the crystal packing, there are two intra-molecular
CAH. . .O1/N2 and an intermolecular CAH. . .N hydrogen bonding,
details of which are given in Table 3. Intra molecular hydrogen
bonds are shown in Fig. 1. In addition, inter molecular hydrogen
bonding, the atom C13 of cyclobutane ring at (x, y, z) acts as hydro-
gen-bond donor, via atom H13, to atom N4 of the triazole ring at
(1/2 ꢁ x, ꢁ1/2 + y, 1/2 ꢁ z). This dimers stabilize crystal packing
in three dimensional space (see Fig. 2).
Bond angles (°)
C4AN1AC3
C11AC12AC13
C11AC12AO1
C12AC11AS1
C11AS1AC7
S1AC7AN2
S1AC7AN4
C7AN2AC6
N2AC6AN3
C6AN3AN4
N3AN4AC7
N4AC7AN2
N2AC8AC9
116.2(2)
116.5(2)
121.6(2)
115.7(2)
100.6(1)
125.3(2)
124.2(2)
104.6(2)
110.3(2)
107.2(2)
107.5(2)
110.4(2)
117.3(2)
116.6
114.9
122.7
115.3
98.7
124.0
125.2
103.9
109.9
108.1
107.3
110.8
114.8
116.7
114.7
122.7
115.4
98.5
124.0
125.2
103.9
109.8
108.1
107.4
110.7
115.0
Torsion angles (°)
C18AC15AC16AC13 137.7(2)
C15AC16AC13AC12 ꢁ139.3(2)
C16AC13AC12AC11 ꢁ80.9(3)
136.1
ꢁ136.8
ꢁ88.3
169.6
73.2
135.6
ꢁ136.4
ꢁ85.1
169.6
73.1
C13AC12AC11AS1
C12AAC11AS1AC7
O1AC12AC11AS1
C11AS1AC7AN4
C11AS1AC7AN2
S1AC7AN4AN3
S1AC7AN2AC6
168.6(2)
89.5(2)
ꢁ8.7(3)
ꢁ9.1
ꢁ9.5
77.0(2)
58.8
58.8
ꢁ104.6(2)
179.9(2)
ꢁ179.3(2)
ꢁ2.7(5)
ꢁ121.3
ꢁ179.4
ꢁ180.0
ꢁ2.2
ꢁ120.5
ꢁ178.7
179.3
ꢁ1.4
N2AC8AC9AC10
Table 3
Hydrogen bond interactions of the title compound (1) (Å, °).
3.2. Theoretical studies using DFT method
Hydrogen bond (Å, °)
DAH
H. . .A
D. . .A
DAH. . .A
3.2.1. Optimized structure
C13AH13. . .N4i
C8AH8A. . .O1
C10AH10A. . .N2
0.98
0.97
0.93
2.49
2.29
2.55
3.387(3)
3.220(6)
2.883(5)
153
161
102
The optimized molecular geometries are calculated by using
B3LYP/6-31G(d) and B3LYP/6-311G(d, p) methods. Some selected
geometric parameters experimentally obtained and theoretically
calculated by B3LYP/6-31G(d) and B3LYP/6-311G(d, p) methods
Symmetry code: (i): 1/2 ꢁ x, ꢁ1/2 + y, 1/2 ꢁ z.
Fig. 1. ORTEP drawing of the basic crystallographic unit including intramolecular hydrogen bonds, showing the atom-numbering scheme. Displacement ellipsoids are drawn
at the 30% probability level and H atoms are shown as small spheres of arbitrary radii.

4
Ç.Y. Ataol, Ö. Ekici / Journal of Molecular Structure 1065-1066 (2014) 1–9
Fig. 2. A diagram showing the CAH. . .N intermolecular hydrogen bonds in the title compound. Only those H atoms involved in the hydrogen bonding interactions are shown.
[Symmetry code: (i):1/2 ꢁ x, ꢁ1/2 + y, 1/2 ꢁ z.]
are listed in Table 1 and compared with X-ray results. We noted
that the experimental results belong to solid phase and theoretical
calculations belong to gaseous phase. In the solid state, the exis-
tence of the crystal field along with the intermolecular interactions
have connected the molecules together, which result in the differ-
ences of bond parameters between the calculated and experimen-
tal values. It is well known that DFT optimized geometric
parameters are usually good agreement with experimental values
and more accurate than Hartree–Fock and semi-empirical meth-
ods, due to inclusion of electron correlation. The largest differences
between experimental and calculated bond lengths, bond angles
and torsion angles are about 0.027 Å and 0.026 Å, 2.5° and 2.3°,
18.2° and 18.2° for B3LYP/6-31G(d) and B3LYP/6-311G(d, p),
respectively. Both the optimized bond lengths and bond angles
provided by B3LYP/6-311G(d, p) method are the closest to the
experimental values (see Table 1).
harmonic vibrations [31]. To describe the observed modes, we cal-
culate harmonic vibrational frequencies and compare theoretical
and experimental results (see Table 4).
The characteristic
t(CH) stretching vibrations of heteroaromatic
structures are expected to appear in 3000–3100 cmꢁ1 [27]. In the
present study, t(CH) symmetric and asymmetric stretching modes
are observed in the range of 3019–3089 cmꢁ1. The experimental
C@O stretching mode is observed at 1707 cmꢁ1. In the pyridine
and triazole rings, CN and C@N stretching vibrations are observed
at 1510/1263 cmꢁ1 and 1606 cmꢁ1
, respectively. Also, t(SC)
stretching mode is observed at 674 cmꢁ1. The other stretching,
bending, twist, rocking, scissorsing modes can be seen in Table 4.
Despite the differences between observed and calculated values,
the general agreement is good.
3.2.3. Molecular electrostatic potential
Electrostatic potential maps, also known as electrostatic poten-
tial energy maps, or molecular electrical potential surfaces, illus-
trate the charge distributions of molecules three dimensionally.
The purpose of finding the electrostatic potential is to find the
reactive site of a molecule. These maps allow us to visualise vari-
ably charged regions of a molecule. Knowledge of the charge distri-
butions can be used to determine how molecules interact with one
another. Molecular electrostatic potential (MESP) mapping is very
useful in the investigation of the molecular structure with its phys-
iochemical property relationships [32].
3.2.2. Vibrational spectra
IR spectrum is obtained using an ATI Unicam-Mattson 1000
FTIR spectrophotometer using KBr pellets and IR spectrum of this
structure is shown in Fig. 3. Harmonic vibrational frequencies were
calculated by using B3LYP/6-31G(d) and B3LYP/6-311G(d, p) lev-
els. The experimental and calculated frequencies show differences.
The first reason is that the experimental spectrum has been re-
corded for the compound in the solid state, while the computed
spectra correspond to isolated molecule in the gas phase. The sec-
ond reason is the fact that the experimental values correspond to
anharmonic vibrations, whereas the calculated values are
The molecular electrostatic potential, V(r), at a given point r(x, y,
z) in the vicinity of a molecule, is defined in terms of the
80
70
475
512
1647
1301
1494
1264
60
1027
1345
3091
50
584
548
3055
3018
1063
%
T
2862
40
30
20
10
1393
2914
2934
834
769
2970
1457
1429
1212
1140
1095
934
1606
983
701
1711
4000
3500
3000
2500
2000
1500
1000
500
Wavenumbers, nm
Fig. 3. FTIR spectrum of the title compound.

Ç.Y. Ataol, Ö. Ekici / Journal of Molecular Structure 1065-1066 (2014) 1–9
5
Table 4
Vibrational frequencies of the title compound (1) with experimental and DFT/B3LYP
Methods.
Frequencies
Experimental B3LYP 6-
31G(d)
B3LYP 6-311G(d,
p)
t
t
t
t
t
t
t
t
t
t
t
t
as(CH2) all.
s(CH) pyr.
as(CH) pyr.
s(CH) phe.
as(CH) phe.
3108
3089
3055
3040
3019
2968
2959
2951
2933
2915
2859
2818
3224
3152
3146
3189/3154
3177–3169
3145
3135
3121–3105
3098
3092/3083
3087
3062–3059/
3048
3252
3178
3172
3209
3197–3189
3174
3161
3142–3126
3117
3118/3107
3112
s(CH2) +
s(CH2) +
t
t
s(CH) all.
as(CH) all.
as(CH2) cyc.
as(CH2)
as(CH3)
as(CH2) all.
s(CH2) +
t
(CH) cyc.
3081–3078/3069
t
t
t
t
t
t
t
t
s(CH2) all.
s(CH2)
s(CH3)
(C@O)
(C@C)
(CC) phe.
(CC) pyr.
(CN) pyr.
–
–
–
3054
3050
3019
1784
1710
1646
1639
1594
3074
3067
3040
1804
1733
1664
1655
1610
Fig. 4. The total electron density surface mapped with electrostatic potential of the
title compound by B3LYP/6-311G(d, p).
1707
1606
1557
1534
1510
1494
1465
1455
integration variable. The MEP is related to the electronic density
and is a very useful descriptor in understanding sites of electro-
philic attack and nucleophilic reactions as well as hydrogen bond-
ing interactions [34–36]. The electrostatic potential V(r) is also
well suited for analyzing processes based on the ‘‘recognition’’ of
one molecule by another, such as in drug–receptor and enzyme–
substrate interactions, because it is through their potentials that
the two species first ‘‘see’’ each other [37,38]. Being a real physical
property, V(r) can be determined experimentally by diffraction or
computational methods [39].
Total SCF electron density surface mapped with molecular elec-
trostatic potential (MESP) of the title compound (1) are shown in
Fig. 4. The molecular electrostatic potential surface MESP which
is a 3D plot of electrostatic potential mapped onto the iso-electron
density surface simultaneously displays molecular shape, size and
electrostatic potential values. The colour scheme for the MESP sur-
face is red-electron rich or partially negative charge; blue-electron
deficient or partially positive charge; light blue-slightly electron
deficient region; yellow-slightly electron rich region, respectively.
Areas of low potential, red1, are characterized by an abundance of
electrons. Areas of high potential, blue, are characterized by a rela-
tive absence of electrons. Nitrogen has a higher electronegativity va-
lue would consequently have a higher electron density around them.
Thus the spherical region that corresponds to nitrogen atom would
have a red portion on it. The MESP of the compound clearly indicates
the electron rich centres of nitrogen and oxygen atoms. The contour
map of electrostatic potential of the compound has been constructed
by the DFT method and is shown in Fig. 5 also confirms the different
negative and positive potential sites of the molecule in accordance
with the total electron density surface.
d(CH) phe.
s(CH2) +
1529
1503/1493
1496
1548/1493
1529–1520
1509
q
q
s(CH3) cyc.
d(CH) pyr. + d(NCN)
tri.
s(CH2) all.
q
q
q
q
q
1429
1403
1393
1374
1343
1606
1298
1263
1220
1206
1491
1455
1449
1422
1412
1412
1395
1378
1375
1321
1513
1471
1467
1452
s(CH) + (CNC) pyr.
t
s(CH2) + d(CH) all.
s(CH2)
t(CH3)
(C@N) tri.
1435
t
1444/1425
1425/1410
1392
1390
1335
d(CH2) all.
t(CH2) all. +
d(CH)
t
(CN) tri.
t
(Cphe.Ccyc.) + d(CH2)
cyc.
d(CH2)
1188
1293
1286
1268
1249
1220
1203
1174
1137/1091
1017
1114
1010
1001
992/852
981
1309
1297
1290
1267/1095
1226
1215
1167/1122
1144
1057/1017
1122
1012
994
989
1006/988
950
766
t(CH2) all. + d(NCN) tri. 1171
t
(CNC) pyr.
t(CH2) + t(CH) cyc.
t(CH2) all.
1135
1092
1074
1062
1027
982
945
926
883
868
831
766
740
728
701
674
q
q
s(CH) phe.
t(CH2) +
qt(CH3) cyc.
t
(NN) tri.
h(phe.)
s(CH) pyr.
q
h(pyr.)
t(CH) phe.
t(CH) pyr.
h(cyc.)
d(CH2) all.
d(CCS)
d(NCN) out of plane
m
953
762
725
724
778/721
728
(SC)
all.: allyl, pyr.: pyridin, phe.: phenyl, cyc.: cyclobutyl, tri: triazole,
twist, d: bending, qs scissorsing, ts symmetric stretching, tas
stretching, h: breathing.
q
:
t: rocking, t:
asymmetric
:
:
3.2.4. Natural bond orbital analysis
interaction energy between the electrical charge generated from
the molecule’s electrons and nuclei and a positive test charge (a
proton) located at r. For the system studied, the V(r) values were
calculated as described previously using the following equation
[33]:
The charges of the atoms determined by natural bond orbital
(NBO) analysis by B3LYP/6-31G(d) and B3LYP/6-311G(d, p) meth-
ods are presented in Table 5. The more positive charges on C12
and C6 carbon atoms are due to the highly electronegative nitrogen
and oxygen attachment with that carbon atom. This is caused by
the electronegativity of nitrogen and oxygen atoms. When com-
pared the charges of the aromatic ring carbon atoms, less positive
Z
X
ZA
jRA ꢁ rj
VðrÞ ¼
ꢁ
q
ðr0Þ=jr0 ꢁ rjd3r0
ð1Þ
(r0) is the
1
where ZA is the charge of nucleus A located at RA,
q
For interpretation of color in Fig. 4, the reader is referred to the web version of
electronic density function of the molecule, and r0 is the dummy
this article.

6
Ç.Y. Ataol, Ö. Ekici / Journal of Molecular Structure 1065-1066 (2014) 1–9
The 13C chemical shift values (with respect to TMS) are ob-
served to be 204.13–30.36 ppm range and it is found that these
values are at the 198.795–31.889 ppm range by the
B3LYP/6-31G(d) level and 213.946–34.518 ppm range by the
B3LYP/6-311G(d, p) level. 13C NMR spectra of the title compound
show the signals at 153.69 and 150.85 ppm related to C(6) and
C(7) atoms next to the N atoms of the five-membered triazole ring.
This signals are calculated as 149.329 and 162.148 ppm for the
C(6) atom and 152.474 and 164.694 ppm for the C(7) atom by
using the B3LYP/6-31G(d) and B3LYP/6-311G(d, p) levels, respec-
tively. The chemical shift values of C12 atom next to oxygen atom
are observed as 204.13 ppm in the 13C NMR spectra.
Besides of the 13C chemical shift values, the 1H chemical shift
values are observed in the range of 8.75–1.46 ppm and the 1H
chemical shift values (with respect to TMS) have been calculated
as 8.739–1.208 ppm with B3LYP/6-31G(d) level and 9.031–
1.203 ppm with B3LYP/6-311G(d, p) level.
Fig. 5. The contour map of electrostatic potential of the total density of the title
compound by B3LYP/6-311G(d, p).
Table 5
The charges of the atoms determined from natural bond orbital analysis (NBO) by
B3LYP method.
3.2.6. Thermodynamic properties
In this study, we calculated total energy, dipole moment, zero-
point vibrational (ZPVE) energy and the standard thermodynamic
parameters such as standard heat capacity Cvib, standard entropy
Svib and standard enthalpy Hvib of the title compound at 298.15 K
temperature and 1 atm pressure by using B3LYP/6-31G(d) and
B3LYP/6-311G(d, p) levels. As can be seen in Table 7, the ZPVE
and Etotal of the molecular structure obtained by the B3LYP/6-
311G(d, p) method are much lower than that obtained by the
B3LYP/6-31G(d) method. They are at 268.131 kcal molꢁ1 and
Atoms B3LYP 6-
31G(d)
B3LYP6-
311G(d, p)
Atoms B3LYP 6-
31G(d)
B3LYP 6-
311G(d, p)
S1
N1
N2
N3
N4
O1
C1
C2
C3
C4
C5
C6
C7
C8
C9
C10
C11
C12
C13
C14
C15
C16
C17
C18
C19
C20
C21
C22
C23
0.2937
ꢁ0.4483
ꢁ0.4004
ꢁ0.2857
ꢁ0.3070
ꢁ0.5528
ꢁ0.0725
ꢁ0.2679
0.0243
0.2461
ꢁ0.4486
ꢁ0.4133
ꢁ0.2906
ꢁ0.3171
ꢁ0.5664
ꢁ0.0627
ꢁ0.2418
0.0680
H2
H3
H4
H5
H8A
H8B
H9
H10A
H10B
H11A
H11B
H13
H14A
H14B
H16A
H16B
H17A
H17B
H17C
H19
H20
H21
H22
H23
0.2468
0.2245
0.2262
0.2614
0.2870
0.2610
0.2372
0.2238
0.2292
0.2722
0.2879
0.2556
0.2576
0.2384
0.2374
0.2456
0.2265
0.2375
0.2400
0.2349
0.2367
0.2364
0.2361
0.2317
0.2161
0.1824
0.1841
0.2274
0.2479
0.2202
0.1985
0.1919
0.1956
0.2320
0.2480
0.2143
0.2211
0.2006
0.1989
0.2059
0.1917
0.2008
0.2034
0.2024
0.2008
0.2010
0.2003
0.1991
284.851 kcal molꢁ1 270.133 kcal molꢁ1 and 286.809 kcal molꢁ1
,
by using B3LYP/6-311G(d, p) and B3LYP/6-31G(d) methods,
respectively. The results of the energies, dipole moment, enthalpy,
entropy, heat capacity, and ZPVE provide helpful information to
further study the title compounds. They can be used to compute
the other thermodynamic energies according to relationships of
thermodynamic functions and estimate directions of chemical
reactions according to the second law of thermodynamics in ther-
mochemical fields.
0.0211
0.0655
ꢁ0.2355
ꢁ0.2049
0.3571
0.3586
0.1762
0.2234
ꢁ0.2939
ꢁ0.2392
ꢁ0.4323
ꢁ0.6854
0.5969
ꢁ0.3448
ꢁ0.4381
ꢁ0.0599
ꢁ0.4298
ꢁ0.6625
ꢁ0.0353
ꢁ0.2288
ꢁ0.2245
ꢁ0.2392
ꢁ0.2254
ꢁ0.2318
ꢁ0.2178
ꢁ0.1872
ꢁ0.3733
ꢁ0.5822
0.6053
ꢁ0.2974
ꢁ0.3745
ꢁ0.0304
ꢁ0.3612
ꢁ0.5621
ꢁ0.0307
ꢁ0.2043
ꢁ0.1858
ꢁ0.2047
ꢁ0.1871
ꢁ0.2075
3.2.7. Electronic absorption spectra
The excited states were taken into account for the TD-DFT
method based on the B3LYP/6-311G(d, p) and B3LYP/6-31G(d) lev-
els including chloroform solvent in order to investigate the proper-
ties of electronic absorption. The energies of four important
molecular orbitals of the title compound (1): the second highest
and highest occupied MO’s (HOMO and HOMOꢁ1), the lowest
and the second lowest unoccupied MO’s (LUMO and LUMO+1)
were calculated and are presented in Table 8.
It is known that photon energy E is given by:
charge is observed in the C3 and C4 carbon atoms which is at-
tached to the highly electronegative nitrogen (N1) atom.
E ¼ hc=k
ð2Þ
where h is the Planck’s constant, c is the light velocity in vacuum,
and k is the wavelength of light. For molecular maximum absorp-
tion spectrum, E can be replaced with molecular orbital energy level
3.2.5. NMR spectra
The ‘‘gauge-independent atomic orbital’’ (GIAO) method has
proven to be quite accepted and accurate, in particular when ap-
plied in the context of highly correlated ab initio methods, such
as perturbation theory and coupled cluster theory. Both ap-
proaches are computationally expensive and time consuming and
often cannot be applied to larger molecular systems. Density Func-
tional Theory (DFT) shielding calculations are rapid and applicable
to large systems, but the paramagnetic contribution to the shield-
ing trends to be overestimated. In this sense, theoretical calcula-
tions of the chemical shifts may be used as an aid for the
assignment of the experimental data. The results of these calcula-
tions are tabulated in Table 6. The theoretical 13C and 1H chemical
shift values (with respect to TMS) of the title compound are com-
pared to the experimental 13C and 1H chemical shift values.
difference (
DE); thus, Eq. (3) changes to [40]:
D
E ¼ hc=k
ð3Þ
The calculations were also performed with CHCl3 solvent effect. The
energy gap between HOMO and LUMO is a critical parameter in
determining molecular electrical transport properties [32]. The
experimental and calculated UV–Vis absorption spectrums are
shown in Fig. 6. Experimentally, electronic absorption spectrum of
the title compound in CHCl3 solvent shows two bands at 274 and
256 nm. One of the absorption bands at 274 nm is caused by the
n ? p* transition and the other band at 256 nm is due to
transition. The
p* transitions are expected to occur relatively
at lower wavelength, due to the consequence of the extended aro-
p ?
p*
p
?

Ç.Y. Ataol, Ö. Ekici / Journal of Molecular Structure 1065-1066 (2014) 1–9
7
Table 6
Theoretical and experimental 13C and 1H isotropic chemical shifts (diso) (with respect to TMS all values in ppm) for the title compound.
Atoms
Exp.
B3LYP 6-31G(d) (diso
)
B3LYP 6-311G(d, p) (diso
)
Atoms
Exp.
B3LYP 6-31G(d) (diso
)
B3LYP 6-311G(d, p) (diso)
C1
C2
C3
C4
C5
C6
C7
C8
134.27
122.11
152.64
152.64
122.11
153.69
150.85
39.08
130.92
118.66
41.27
204.13
47.05
36.69
38.47
36.69
30.36
150.63
124.56
128.32
125.67
128.32
124.56
129.336
114.579
144.131
144.578
117.650
149.329
152.474
49.289
129.461
110.094
50.715
198.795
39.386
33.559
41.194
41.418
31.889
145.376
118.494
121.827
119.178
121.755
118.379
141.801
125.167
157.168
157.643
128.619
162.148
164.694
53.838
145.166
121.104
54.553
213.946
42.444
35.824
45.003
45.345
34.518
161.743
130.713
–
H2
H3
H4
H5
H8A
H8B
H9
H10A
H10B
H11A
H11B
H13
H14A
H14B
H16A
H16B
H17A
H17B
H17C
H19
H20
H21
H22
H23
7.65
8.75
8.75
7.65
4.73
4.73
5.90–6.01
4.86
5.25
4.34
4.34
3.74
2.33
2.28
2.50
2.43
1.46
7.287
8.673
8.739
7.802
5.604
4.482
6.334
4.930
5.481
3.628
4.293
3.328
2.859
1.912
2.639
2.197
1.782
1.250
1.208
7.016
7.209
7.124
7.227
6.960
7.628
8.963
9.031
8.162
5.841
4.703
6.609
5.092
5.683
3.846
4.382
3.297
2.842
1.842
2.654
2.105
1.756
1.259
1.203
7.277
7.497
7.389
7.508
7.229
C9
C10
C11
C12
C13
C14
C15
C16
C17
C18
C19
C20
C21
C22
C23
1.46
1.46
7.28–7.32
7.12–7.18
7.12–7.18
7.12–7.18
7.28–7.32
131.643
134.488
130.859
Table 7
The calculated thermodynamic parameters of compound (1) using by B3LYP/6-
311G(d, p), B3LYP/6-31G(d) methods.
Thermodynamic parameters (298 K and
1 atm)
B3LYP/6-
31G(d)
B3LYP/6-
311G(d, p)
SCF energy (Hartree)
ꢁ1583.251
286.809
101.164
ꢁ1583.566
284.851
101.604
Total energy (thermal), Etotal (kcal molꢁ1
Heat capacity at const. volume, Cvib
)
(cal molꢁ1 Kꢁ1
)
Entropy, Svib (cal molꢁ1 Kꢁ1
)
188.227
17.269
285.032
270.133
188.461
17.313
283.074
268.131
Enthalpy, H (kcal molꢁ1
)
Vibrational energy, Evib (kcal molꢁ1
Zero-point vibrational energy, E0
)
(kcal molꢁ1
)
Rotational constants (GHz)
A
B
C
0.264
0.063
0.059
5.593
0.267
0.062
0.059
5.576
Dipole moment (Debye)
Fig. 6. The experimental and the calculated UV–Vis absorption spectra of the title
compound.
maticity of the benzene, triazole and pyridine rings. Then the n ? p*
transition is more significant due to the presence of lone pair of
electrons in the oxygen and nitrogen atoms in the molecular struc-
ture. Some frontier molecular orbitals are shown in Fig. 7. As shown
from Fig. 7, the electron clouds of the HOMO and HOMOꢁ1 are
delocalized all of the molecule and benzene moiety, respectively.
This orbitals are seem to be the
p-bonding type orbital. LUMO is
found mainly delocalized on triazole and pyridine rings but
LUMO+1 is found mainly delocalized on carbonyl group. The
energy gap of HOMO–LUMO explains the eventual charge transfer
Table 8
The calculated absorption wavelength (k), excitation energies (E), oscillator strength (f) and frontier orbital energies of compound (1) by TD-DFT method.
Methods
k (nm)
E (eV)
f
EHOMO (eV)
ꢁ6.430
ELUMO (eV)
ꢁ1.488
EHOMOꢁ1 (eV)
ꢁ6.572
ELUMO+1 (eV)
ꢁ0.835
B3LYP 6-31G(d)
282.95
278.17
271.37
4.3819
4.4571
4.5689
0.2786
0.0790
0.0176
B3LYP 6-311G(d, p)
Experimental
285.08
276.86
274.51
4.3490
4.4782
4.5165
0.3320
0.0140
0.0170
ꢁ6.631
ꢁ1.723
ꢁ6.817
ꢁ1.023
274
256

8
Ç.Y. Ataol, Ö. Ekici / Journal of Molecular Structure 1065-1066 (2014) 1–9
slightly different from its optimized structures. The results show
that the optimized bond lengths are slightly longer than the
experimental values, and the optimized bond angles are slightly
different from the experimental ones. It was noted that the exper-
imental results belong to solid phase and theoretical calculations
belong to gaseous phase. Also, the other experimental results are
in good agreement with the theoretical results.
LUMO +1 : -0.835 eV
LUMO +1 : -1.023 eV
Supplementary data
Crystallographic data for the structural analysis have been
deposited with the Cambridge Crystallographic Data Centre, CCDC
No. 808472. Copies of this information may be obtained free of
charge from the Director, CCDC, 12 Union Road, Cambridge CB2
1EZ, UK (fax: +44 1223 336033; e-mail: deposit@ccdc.cam.ac.uk
or www: http://www.ccdc.cam.ac.uk).
LUMO : -1.488 eV
LUMO : -1.723 eV
Acknowledgments
The authors wish to acknowledge the Faculty of Arts and
Sciences, Ondokuz Mayis University, Turkey, for the use of the
STOE IPDS-II diffractometer (purchased under Grant F.279 of the
University Research Fund).
HOMO : -6.430 eV
HOMO : -6.631 eV
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4. Conclusion
In this study, we investigate X-ray structure, IR, 1H NMR, 13C
NMR of the title compound. In addition to the experimental stud-
ies, most of the properties of the molecular structure have been
calculated by using B3LYP/6-31G(d) and B3LYP/6-311G(d, p) basis
sets. Single crystal structure has been compared the optimized
molecular structure. The X-ray structure is found to be very
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