Nonlinear optical studies and structure-activity relationship of chalcone derivatives with in silico insights

Article abstract of DOI:10.1016/j.molstruc.2017.03.064

Nine chalcones were prepared via Claisen-Schmidt condensation, and characterized by UV–vis, IR¹H NMR¹³C NMR and mass spectrometry. One of the representative member 4-NDM-TC has been studied via single crystal XRD and the TGA/DTA tech

Full text of DOI:10.1016/j.molstruc.2017.03.064

Journal of Molecular Structure 1139 (2017) 294e302
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: http://www.elsevier.com/locate/molstruc
Nonlinear optical studies and structure-activity relationship of
chalcone derivatives with in silico insights
Swayamsiddha Kar a, K.S. Adithya b, Pruthvik Shankar a, N. Jagadeesh Babu c,
,
*
Sailesh Srivastava b, G. Nageswara Rao a
a Department of Chemistry, Sri Sathya Sai Institute of Higher Learning, Andhra Pradesh 515134, India
b Department of Physics, Sri Sathya Sai Institute of Higher Learning, Andhra Pradesh 515134, India
c Indian Institute of Chemical Technology, Hyderabad 500007, India
a r t i c l e i n f o
a b s t r a c t
Nine chalcones were prepared via Claisen-Schmidt condensation, and characterized by UVevis, IR, 1H
NMR, 13C NMR and mass spectrometry. One of the representative member 4-NDM-TC has been studied
via single crystal XRD and the TGA/DTA technique. SHG efficiency and NLO susceptibilities of the chal-
cones have been evaluated by the Kurtz and Perry method and Degenerate Four Wave Mixing techniques
respectively. 3-Cl-40-HC was noted to possess SHG efficiency 1.37 times that of urea while 4-NDM-TC
returned the highest third order NLO susceptibilities with respect to CS2. In silico studies help evaluate
various physical parameters, in correlating the observed activities. In conclusion, the structure-activity
relationship was derived based on the in silico and experimental results for the third order NLO
susceptibilities.
Article history:
Received 29 January 2017
Received in revised form
16 March 2017
Accepted 16 March 2017
Keywords:
Chalcones
SHG efficiency
Degenerate four wave mixing
Structure-activity relationship
Molecular modeling
Theoretical studies
© 2017 Elsevier B.V. All rights reserved.
1. Introduction
p-electron acceptor. Chalcones satisfy these criteria given their p-
conjugated bridge that can be manipulated with a wide range of
substitutions.
Various substances/compounds have been studied for optical
properties to be used for several optical devices which include
optical switching, optical limiting, etc. [1e3]. The main re-
quirements for the application are high and fast Nonlinear Optical
(NLO) responses. Among the large varieties of materials evaluated,
organic materials have attracted attention due to their high non-
linear properties and ultrafast response. Conjugated organic sys-
Chalcones have been studied for various biological properties
[5e9] but come into the picture because of their large SHG (Second
Harmonic Generation) efficiencies. Also they have noticeable third-
order nonlinearity. Due to their ability to crystallize in non-centro-
symmetric structure and their blue light transmittance, they have
acquired considerable interest [10e12]. Our main focus is to
establish a structure-activity relationship along with quantitative
measurement of these susceptibilities. Further, to evaluate potential
physical parameters in silico to relate these experimental results.
tems have delocalized
p electrons, which show excellent NLO
properties as they can be easily polarized. A structure-activity
relationship in this regard helps in the design and modeling of
molecules to meet the requirements. The NLO response acquired
for organic molecules can be enhanced by various strategies:
2. Experimental
donoreacceptoredonor (De
p-A-
peD), acceptoredonoreacceptor
(Ae -D- eA) and donore
[4]. There are three features essential for high nonlinear activity
(multi photon absorption) in an organic compound: a strong elec-
p
p
p
edonor (Dep
eD) types of molecules
2.1. Preparation of the chalcones
General scheme for preparation [13]:
tron donor, a highly polarizable
p-conjugated bridge and a strong
The chalcones were prepared (Scheme 1) by dissolving the
required ketone (0.02 mol) and the aldehyde (0.02 mol) in ethanol
(40 ml). Aq. NaOH (30%, 2.7 ml) was added to the above solution
and the reaction mixture was stirred at room temperature. The
* Corresponding author.
E-mail address: gnageswararao@sssihl.edu.in (G. Nageswara Rao).
http://dx.doi.org/10.1016/j.molstruc.2017.03.064
0022-2860/© 2017 Elsevier B.V. All rights reserved.

S. Kar et al. / Journal of Molecular Structure 1139 (2017) 294e302
295
Scheme 1. General Claisen-Schmidt condensation reaction. X & Y represent various substituents and at different positions.
reaction was monitored by Thin Layer Chromatography (TLC). The
reaction time varied depending upon the type of the substituents
present. After the reaction was complete, the contents were filtered
and washed free of alkali. In case of hydroxy-chalcones, NaOH (30%,
5.04 mL) was taken and the solutions were purged with nitrogen
before reaction and nitrogen atmosphere was maintained during
the reaction. After the reaction was complete (shown by TLC), the
contents of the flask were poured into a beaker containing ice. The
pH of the solution was brought to below 7.0 while stirring vigor-
ously to obtain a colored solid. The crude solid was washed with
cold water to remove any excess acid. In all cases, the filtered solid
was dried and re-crystallized from distilled methanol. The com-
pounds prepared along with their sample code, yield and melting
point are shown in Table 1.
evaporation method at room temperature. The recrystallized sub-
stance was used for this purpose and methanol was found to give
the best single crystals. The X-ray data for the compound were
collected at room temperature using a Bruker Smart Apex CCD
diffractometer with graphite monochromated Mo-K
a radiation
(l
¼ 0.71073 Å) with -scan method [14]. Preliminary lattice pa-
u
rameters and orientation matrices were obtained from four sets of
frames. Unit cell dimensions were determined using 5382 re-
flections. Integration and scaling of intensity data were accom-
plished using SAINT program [14]. The structures were solved by
Direct Methods using SHELXS972 and refinement was carried out
by full-matrix least-squares technique using SHELXL-2014/7 [15].
Anisotropic displacement parameters were included for all non-
hydrogen atoms. H bound to N atom was located from the differ-
ence Fourier map. All H atoms were positioned geometrically and
treated as riding on their parent C atoms with C-H distances of
0.93e0.97 Å, and with Uiso(H) ¼ 1.2Ueq (C) or 1.5Ueq for methyl
atoms.
2.2. Single crystal growth and XRD analysis
The single crystal for 4-NDM-TC was obtained by slow
Table 1
Structure, IUPAC names, % yield and melting points of the chalcones prepared.
Substituent
IUPAC name
Code
Yield (%)
85
Melting point (ꢀC)
R1 ¼ -H, R2 ¼ -H,
(E)-1-phenyl-3-(4-N,N-dimethylaminophenyl)prop-2-ene -1-one
4-NDM-C
68e72
R3 ¼ -N(Me)2, R4 ¼ -H
R1 ¼ -H, R2 ¼ -OH,
R3 ¼ -OMe, R4 ¼ -H
R1 ¼ -OH, R2 ¼ -H,
R3 ¼ -OMe, R4 ¼ -H
R1 ¼ -H, R2 ¼ -OH,
R3 ¼ -Cl, R4 ¼ -H
(E)-1-(4-hydroxyphenyl)-3-(4-methoxyphenyl)prop-2-ene-1-one
(E)-1-(2-hydroxyphenyl)-3-(4-methoxyphenyl)prop-2-ene-1-one
(E)-3-(4-chlorophenyl)-1-(4-hydroxyphenyl)prop-2-ene-1-one
4-MO-40-HC
4-MO-20-HC
4-Cl-40-HC
68
76
90
88
64
78
80
182e184.2
186.2e188
190.52
R1 ¼ -H, R2 ¼ -OH,
R3 ¼ -H, R4 ¼ -Cl
(E)-3-(3-chlorophenyl)-1-(4-hydroxyphenyl)prop-2-ene-1-one
3-Cl-40-HC
198e200
R1 ¼ -H, R2 ¼ -OH,
R3 ¼ -N(Me)2, R4 ¼ -H
R1 ¼ -OH, R2 ¼ -H,
R3 ¼ -N(Me)2, R4 ¼ -H
R1 ¼ -H, R2 ¼ -Br,
R3 ¼ -N(Me)2, R4 ¼ -H
(E)-3-(4-(N,N-dimethylamino)phenyl)-1-(4-hydroxyphenyl)prop-2-ene-1-one
(E)-3-(4-(N,N-dimethylamino)phenyl)-1-(2-hydroxyphenyl)prop-2-ene-1-one
(E)-1-(4-bromophenyl)-3-(4-(N,N-dimethylamino)phenyl)prop-2-ene-1-one
4-NDM-40-HC
4-NDM-20-HC
4-NDM-40-BrC
122.3e124.2
171.8e172.9
145.2e146.8
(E)-3-(4-(N,N-dimethylamino)phenyl)-1-(thiophen-2-yl)prop-2-ene-1-one
4-NDM-TC
91
101e103
e

296
S. Kar et al. / Journal of Molecular Structure 1139 (2017) 294e302
2.3. Instrumentation
using formula [22]:
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
2
The 1HNMR spectra were obtained on VARIAN 400 MHz,
13CNMR on VARIAN 101 MHz using TMS as the internal standard.
The NMR spectra for 4-MO-40-HC, 4-Cl-40-HC and 3-Cl-40-HC were
recorded using DMSO-d6 as the solvent whereas CDCl3 was used for
the other chalcones. For mass spectra AGILENT 6430 Triple Quad
LC/MS was employed. The FT-IR spectra were recorded between
400 and 4000 cmꢁ1 using KBr pellets on Thermo-Nicolet Avatar 370
spectrophotometer. UVevis spectra in methanol were recorded in
the wavelength range 200e600 nm using Shimadzu 2450 spec-
trophotometer. The single crystal X-ray diffraction pattern of the
reported sample was recorded using Bruker Smart Apex CCD
diffractometer. The thermal studies were carried out in SDT Q600
(V20.9 Build 20) instrument with the standard DSC-TGA module.
ꢁ
ꢂ
À
Á
4
2
4
c
ð3ÞðsampleÞ
L
nsample
Isample
1 ꢁ RCS
eff
CS2
2
¼
ꢂ
ꢂ
ꢂ
ꢀ
ꢀ
ꢀ
ꢀ
ꢃ
ꢄ
L2sample
2
4
n
I
CS2
ꢀ
ð3ÞðCS Þ
1 ꢁ Rsample
CS2
c
ꢀ
2
eff
where.
ð3Þ
c
is the third order nonlinear susceptibility, R is surface
eff
reflectance, n is Refractive Index of the medium, L is the path length
and I is the intensity of the phase conjugate signal.
2.5. Computational studies
All the chalcones used for the studies were modelled using
GaussView (3.09) [23]. The energy minimization of these molecules
has been carried out using DFT theory using Gaussian 03 [24].
2.4. Nonlinear optical measurements
2.4.1. Powder SHG measurement
3. Results and discussion
Based on the popular Kurtz and Perry [16,17] powder SHG
technique that measures the SHG efficiency of materials using urea
or potassium dihydrogen phosphate (KDP) as standard, 8 ns pulses
of 1064 nm from Nd:YAG laser working at a repetition rate of 10 Hz
was used for SHG measurement. The microcrystalline powdered
samples taken in glass capillary were smeared with laser pulses of
3.1 mJ/pulse energy. A photomultiplier tube was used to detect the
second harmonic wave of 532 nm produced from the sample and
the resultant signal was fed into an oscilloscope. Urea crystals with
uniform particle size were used as reference for the SHG
experiment.
3.1. Characterization
3.1.1. Structural analysis
Fig. 2 shows the ORTEP diagram obtained from the single crystal
XRD study of 4-NDM-TC.
Crystal data for 4-NDM-TC:
C
15H15NOS,
M
¼
257.34,
0.48 ꢂ 0.18 ꢂ 0.09 mm3, monoclinic, space group P21/c (No. 14),
a ¼ 6.3037(5), b ¼ 10.1112(8), c ¼ 21.6280 Å,
b
¼ 103.795(2)ꢀ,
V ¼ 1338.76(18) Å3, Z ¼ 4, Dc ¼ 1.277 g/cm3, F000 ¼ 544, CCD area
detector, MoK
a
radiation,
l
¼ 0.71073 Å, T ¼ 293(2)K, 2qmax ¼ 52.5ꢀ,
13782 reflections collected, 2695 unique (Rint ¼ 0.025), Final
2.4.2. Degenerate four wave mixing technique
GooF ¼ 1.19, R1 ¼ 0.0619, wR2 ¼ 0.1505, R indices based on 2518
A solution of 3 mg/ml of each chalcone dissolved in a mixture of
tetrahydrofuran; methanol (30:70 %v) was prepared for carrying
out the study.
The third order studies were done using the degenerate four
wave mixing technique [18e21]. Fig. 1 displays the experimental
configuration. The input beam is second harmonic (532 nm) of
fundamental 1064 nm wavelength of a Q-switched Nd:YAG laser,
with a pulse width of 7 ns. The experimental setup is shown in
Fig. 1.
reflections with I > 2s
(I) (refinement on F2), 165 parameters,
m
¼ 0.229 mmꢁ1, Min and Max Resd. Dens. ¼ ꢁ0.25 and 0.31 e/Å3.
CCDC 1453426 contains the supplementary crystallographic data
for this paper which can be obtained free of charge at https://
summary.ccdc.cam.ac.uk/structure-summary-form or from the
Cambridge Crystallographic Data Centre (CCDC), 12 Union Road,
Cambridge CB2 1EZ, UK; fax: þ44(0) 1223 336 033; email: deposit@
ccdc.cam.ac.uk.
Given the role of the structure in the consequential property of
the non-linear optics evaluated extensively in our study, we
confirmed the structure using the XRD of the single crystal. Further,
to establish the reliability of the in silico strategy used, we
compared the simulated bond lengths and bond angles obtained
from the least energy conformation of 4-NDM-TC in G03. The
This beam is divided by beam splitters so that the two counter
propagating pump beams have the same energy(18 mJ) and the
probe beam has 5 mJ.The
reference sample CS2.
c
(3) measurements were made using the
The magnitude of the third order nonlinearity was calculated
Fig. 1. The DFWM set-up.

S. Kar et al. / Journal of Molecular Structure 1139 (2017) 294e302
297
Fig. 2. ORTEP diagram of 4-NDM-TC with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of
arbitrary radius.
complete comparison values are tabulated in the supplementary
data (Table SD1 and SD2). The significant correlation of 0.97 and
0.89 with respect to the bond lengths and bond angles respectively
provide the confirmation of the proposed structure and help us
above 3000 cmꢁ1 attached to sp2 carbons. The C]C stretch is seen
at 1600 cmꢁ1. The out of plane bending vibrations of aromatic
system with para substitutions are seen in the 900 cmꢁ1 to
700 cmꢁ1 range. The chalcones with halogen substitutions have
peaks around 650 cmꢁ1 for Br and 720 cmꢁ1 for Cl. Strong band in
the region 850e800 cmꢁ1 shows benzene rings with para di-
substitutions [25e27]. The UVevis spectra for all the chalcones
have been overlaid in Fig. 3.
visualize its D-A-p-D system.
3.1.2. Spectroscopic analysis
The 1H NMR spectra of these compounds were completely
analyzed. The eOH protons which are highly de-shielded due to
Characterization data of the prepared chalcone analogues:
chelation in 2’-hydroxy chalcones were observed at
d
12.95 and
d
13.21 as singlets. Whereas for eOH proton in 4’-hydroxy chal-
cones, the shifts were observed to be relatively less (d 9.85e10.46).
In the case of the 4’-substituted chalcones H-3 and H-5 were
observed as doublets ( 6.90e7.10). These lower values are due to
shielding from the 40 substituent. Whereas H-2 and H-6 were
observed as doublets between 7.50 and 8.20. In 2’-hydroxy
chalcones H-3, H-4, H-5 and H-6 had different chemical shifts. The
two olefinic protons H-8 ( 6.85e7.45) and H-9 ( 7.60e7.97) signals
appeared as doublets with a large coupling constant (J ¼ 13e16 Hz)
indicating the trans double bond. The chalcones with p-substition
showed signals for H-12 and H-14 as doublets in the range
d
d
d
4-NDM-C: 1H NMR(400 MHz, CDCl3)
d, ppm 8.01 (m, 2H, H-2
and H-6), 7.81 (m, 2H, H-3 and H-5), 7.79 (t,1H, H-4), 7.61 (m, 2H, H-
11 and H-15), 7.52 (d, 1H, J ¼ 16 Hz, H-9), 7.48 (d, 1H, J ¼ 16 Hz, H-8),
6.70 (d, 2H, H-12 and H-14), and 3.04 (s, 6H, -N(CH3)2); 13C
d
d
NMR(101 MHz, CDCl3) d, ppm 139.06 (C1), 128.32 (C2, C6), 128.46
(C3, C5), 132.16 (C4), 190.71 (C7), 121.3 (C8), 145.84 (C9), 116.96
(C10), 130.42 (C11, C15), 111.89 (C12, C14), 152.12 (C13), and 40.20
(-N-CH3); IR (KBr disc): 3094-w (alkene C-H stretch), 2941-w,1680-
s(C]O stretch) 1615-s (C]C stretch), 1532,1515-m (aromatic
skeletal bands), 1426 (aromatic C-H bend), 840-s, 822-s (C-H oop
bend); UVevis (MeOH) lmax nm: 202, 264, 420; Mass:
[MþH]þ ¼ m/z 252.0.
d
6.80e7.40. H-11 and H-15 were observed between d 7.45 and
7.83. The spectra are pretty symmetric in case of 4 and 4’-
d
substituted chalcones. In 3-Cl-40-HC, H-11, H-12, H-13 and H-15
showed different shifts which resulted in a multiplet due to both
meta and ortho couplings. In case of 4-NDM-TC we have doublets
for H-1 and H-3 at
identified as a doublet of doublet at
dimethylamino group were identified by the singlet between
d
7.83 and
d
7.63 respectively, whereas H-2 was
d
7.19. The protons in N,N-
4-MO-4′-HC: 1H NMR(400 MHz, CDCl3)
d, ppm 10.40 (s, 1H, 4-
d
3.08e3.04 (6H). Similarly for the methoxy group, singlet between
3.82e3.87 (3H).
d
The 13CNMR spectra of these chalcones indicated the presence
of C]O by the signal between
pected for olefinic carbons and the aryl ring are observed in sp2
region of
111 to 165 as given in the data. The 13CNMR signal of the
methoxy and the N,N-dimethylamino group are observed at around
55.39 and 40.12 respectively.
d 182 and 193. Other signals as ex-
C
d
d
d
All the compounds in the present study showed molecular ions
in their ESI-mass spectra as [MþH]þ peaks. In 4-NDM-TC the [Mþ2]
þ
peak of around 4e5% intensity is observed which indicates the
presence of Sulphur. In case of 3-Cl-40-HC and 4-Cl-40-HC with
[Mþ2] þ peaks around 33% intensity was observed which indicated
the presence of ‘Cl’. In 4-NDM-40BrC, the [M] þ and [Mþ2] þ peaks
were of the same intensity.
The IR spectra for all compounds have the carbonyl absorption
around 1680 - 1660 cmꢁ1. Other features include the hydrogen
Fig. 3. UVevis spectra for all the samples.

298
S. Kar et al. / Journal of Molecular Structure 1139 (2017) 294e302
OH), 8.77 (d, 2H, H-2 and H-6), 7.83 (m, 2H, H-3 and H-5), 7.80 (d,
1H, J ¼ 16 Hz, H-9), 7.60 (d, 1H, J ¼ 16 Hz, H-8), 7.10 (d, 2H, H-11 and
H-15), 6.90 (d, 2H, H-12 and H-14), and 3.82 (s, 3H, -OCH3); 13C
C15), 111.82(C12, C14), 152.23 (C13), and 40.12(-N-CH3); IR (KBr
disc): 3060-w, 2911-w, 1632-s (C]O stretch), 1611-s (C]C stretch),
1559-m, 1487-s(aromatic skeletal bands), 1434-s, 1417-s (aromatic
C-H bend), 1340-s, 1277-s,1177-s (CdO stretch), 1035-s, 989-s, 814-
s, 768s(C-H oop bend); UVevis (MeOH) lmax nm: 202, 275, 435;
Mass: m/z [MþH]þ ¼ 268.0.
NMR(101 MHz, CDCl3) d, ppm 129.76 (C1), 131.45 (C2, C6), 115.73
(C3, C5), 162.42 (C4), 187.44 (C7), 119.96 (C8), 143.112 (C9), 127.92
(C10), 130.96 (C11, C15), 114.77 (C12, C14), 161.52 (C13), and 55.74
(-O-CH3); IR (KBr disc): 3099-w (alkene C-H stretch), 2932-w,1678-
s(C]O stretch) 1615-s (C]C stretch), 1548,1530-m (aromatic
skeletal bands), 1418 (aromatic C-H bend), 1360-m, 1240-s, 1176-s
(CdO stretch), 838-s, 826-s, 733-s (C-H oop bend); UVevis
(MeOH) lmax nm: 201, 234, 344; Mass: [M]þ ¼ m/z 254.9.
4-NDM-4′-BrC: 1H NMR(400 MHz, CDCl3)
d, ppm ¼ 7.87 (d, 2H,
J ¼ 8 Hz, H-2 and H-6), 7.77 (d, 1H, J ¼ 16 Hz, H-9), 7.62 (d, 2H,
J ¼ 8 Hz, H-3 and H-5), 7.55 (d, 2H, J ¼ 7.8 Hz, H-11 and H-15), 7.29
(d, 1H, J ¼ 16 Hz, H-8), 6.71 (d, 2H, J ¼ 7.8 Hz, H-12 and H-14) and
3.04 (s, 6H, -N(CH3)2); 13C NMR(101 MHz, CDCl3)
d,
4-MO-2′-HC: 1H NMR(400 MHz, CDCl3)
d, ppm 12.95 (s, 1H,-
ppm ¼ 137.80(C1), 130.58 (C2, C6), 131.71 (C3, C5), 127.08(C4),
189.39 (C7, C]O), 116.14 (C8), 146.42 (C9), 122.08 (C10), 129.88(C11,
C15), 111.84 (C12, C14), 152.11 (C13), and 40.17(-N-CH3); IR (KBr
disc): 3080-w, 1647-s (C]O stretch),1610(C]C stretch) 1581-m,
1479-s(aromatic skeletal bands), 1430-s 1410-s (aromatic C-H
bend), 1067-s, 982-s, 810-s, 809-s(C-H oop bend), 690-m (C-Br
stretch); UVevis (MeOH) lmax nm: 202, 275, 428; Mass: m/z
[MþH]þ ¼ 330.0 and [MþHþ2]þ ¼ 332.0.
OH), 7.93e7.89 (m, 2H, H-6 and H-9), 7.63 (d, 2H, H-11 and H-15),
7.56e7.46 (m, 2H, H-4 & H-8), 7.02 (d, 1H, H-3), 6.96e6.92 (m, 3H,
H-4, H12 & H-14), and 3.87 (s, 3H, -OCH3); 13C NMR(101 MHz,
CDCl3) d, ppm 120.11 (C1), 163.54 (C2), 118.77 (C3), 136.17 (C4),
117.56 (C5), 129.53 (C6), 193.68 (C7), 118.59 (C8), 145.37 (C9), 127.32
(C10), 130.57 (C11, C15), 114.52 (C12, C14), 162.02 (C13), and 55.47
(-O-CH3); IR (KBr disc): 3095-w (alkene C-H stretch), 2902-w,1668-
s(C]O stretch) 1610-s (C]C stretch), 1545,1525-m (aromatic
skeletal bands), 1422 (aromatic C-H bend),1361-m, 1242-s, 1166-s
(CdO stretch), 835-s, 822-s, 737-s (C-H oop bend); UVevis
(MeOH) lmax nm: 201, 241, 365; Mass: [M]þ ¼ m/z 254.9.
4-Cl-4′-HC: 1H NMR(400 MHz, CDCl3)
8.09 (d, 2H, H-2 and H-6), 7.93 (m, 3H, H-9, H-11 and H-15), 7.67 (d,
1H, H-8), 7.51 (d, 2H, H12 &H-14), and 6.91 (d, 2H, H-3 and H-5); 13
NMR(101 MHz, CDCl3); , ppm 130.82 (C1), 131.68 (C2, C6), 115.80
d, ppm 10.46 (s, 1H,-OH),
C
d
(C3, C5), 162.70 (C4), 187.40 (C7), 123.26 (C8), 141.66 (C9), 134.29
(C10), 129.42 (C11, C15), 129.31 (C12, C14), and 135.18 (C13); IR (KBr
disc): 3098-w (alkene C-H stretch), 1675-s(C]O stretch) 1606-s
(C]C stretch), 1558,1555-m (aromatic skeletal bands), 1420 (aro-
matic C-H bend),1376-m, 1238-s, 1160-s (CdO stretch), 826-s, 812-
s, 727-s (C-H oop bend); UVevis (MeOH) lmax nm: 201, 229, 321;
Mass: [M]þ ¼ 258.9, [Mþ2]þ ¼ m/z 260.9.
4-NDM-TC: 1H NMR(400 MHz, CDCl3)
d, ppm ¼ 7.83 (d, 1H,
J ¼ 4.0 Hz, H-1), 7.82 (d, 1H, J ¼ 15.2 Hz, H-7), 7.62 (d, 1H, J ¼ 4.0 Hz,
H-3), 7.55 (d, 2H, J ¼ 8.0 Hz, H-9 and H-13), 7.24 (d, 1H, J ¼ 15.2 Hz,
H-6), 7.16 (dd, 1H, J ¼ 4.0 Hz, 4.8 Hz, H-2), 6.72 (d, 2H, J ¼ 8.0 Hz, H-
10 and H-12) and 3.04 (s, 6H, -N(CH3)2);13C NMR(101 MHz, CDCl3)
d
, ppm ¼ 144.95(C1), 130.94 (C2), 132.90 (C3), 146.34 (C4), 182.13
3-Cl-4′-HC: 1H NMR(400 MHz, CDCl3)
d
, ppm 10.47 (s, 1H, -OH),
(C]O, C5), 151.98 (C11), 111.88 (C6), 130.50 (C7), 116.28(C8), 130.48
(C9 and C13), 128.08 (C10 and C12), and 55.39 (dN(CH3)2); IR (KBr
disc): 3080-w (alkene C-H stretch), 1632-s (C]O stretch), 1611-s
(C]C stretch), 1559-m (aromatic skeletal bands), 1434-s, 1417-s
(aromatic C-H bend), 1295-m, 1206-s, 859-s, 839-s, 809-s (C-H
oop bend); UVevis (MeOH) lmax nm: 203, 280, 430, 428; Mass: m/z
[MþH]þ ¼ 258.0, [Mþ2þH]þ ¼ 260, [MþH-CH3]þ ¼ 243 and [M-
C4H3S]þ ¼ 174.
8.11 (d, 2H, H-2 and H-6), 8.07 (m, 2H, H-11 &H-15), 7.80 (d, 1H,
J ¼ 15.6, H-9), 7.66 (d,1H, J ¼ 15.6, H-8), 7.48 (m, 2H, H-13 and H-14)
and 6.91 (d, 2H, H-3 and H-5); 13C NMR(101 MHz, CDCl3)
d, ppm
131.06 (C1), 131.78(C2, C6), 115.80 (C3, C5), 162.77 (C4), 187.36 (C7),
124.05 (C8), 141.44 (C9), 137.60 (C10), 128.21 (C11), 130.27 (C12),
129.35 (C13), 134.12 (C14), 128.17(C15); IR (KBr disc): 3099-w
(alkene C-H stretch), 2926-w, 1670-s(C]O stretch) 1605-s (C]C
stretch), 1548,1535-m (aromatic skeletal bands), 1430 (aromatic C-
H bend),1371-m, 1232-s, 1170-s (CdO stretch), 825-s, 812-s, 727-s
(C-H oop bend); UVevis (MeOH) lmax nm: 202, 233, 318; Mass:
[M]þ ¼ m/z 258.9, [Mþ2]þ ¼ m/z 260.9.
3.2. Thermal studies for 4-NDM-TC
Thermal analysis of
a material gives useful information
4-NDM-4′-HC: 1H NMR(400 MHz, CDCl3)
d
, ppm ¼ 9.85 (s, 1H,
regarding the thermal stability of that material [28]. To find the
thermal stability of 4-NDM-TC, thermo gravimetric analysis was
carried out. Dried crystals of 4-NDM-TC were selected for this
purpose and the analysis was carried out under nitrogen flow of
100 mL/min 30 ꢀC was chosen as the temperature to equilibrate and
then the instrument was heated to 600 ꢀC at a heating rate of 10 ꢀC/
min in the SDT Q600 TGA/DTA analyzer.
The results obtained from this analysis are depicted in Fig. 4. The
DTA curve implies that the material undergoes an irreversible
endothermic transition at 101 ꢀC, where melting begins. The
endothermic peak represents the temperature at which the melting
terminates, which corresponds to its melting point at 103 ꢀC.
Further it indicates that there is no phase transition before melting.
The peak shows the good degree of crystallinity and purity of the
sample. The TGA curve of this sample indicates that the sample is
stable upto 310 ꢀC and above this temperature the weight loss is not
due to self-degradation of 4-NDM-TC, but merely due to evapora-
tion after its melting. The exothermic peak at 335.0 ꢀC indicates that
the sample undergoes decomposition at this temperature.
-OH), 7.98 (d, 1H, H-9), 7.41e7.79 (m, 5H),7.05 (d, 2H, H-3 and H-5),
6.74 (d, 2H, H-12 and H-14) and 3.05 (s, 6H, -N(CH3)2); 13C
NMR(101 MHz, CDCl3)
d, ppm ¼ 130.59 (C1), 131.37 (C2, C6), 116.45
(C3, C5), 164.32 (C4), 189.77 (C7, C]O), 121.45 (C8), 145.18 (C9),
124.78 (C10), 129.56 (C11, C15), 111.75 (C12, C14), 153.5 (C13), and
40.39(-N-CH3); IR (KBr disc): 3094-w (alkene C-H stretch), 2906-w,
1660-s(C]O stretch) 1600-s (C]C stretch), 1548,1535-m (aromatic
skeletal bands), 1432 (aromatic C-H bend),1371-m, 1232-s, 1164-s
(CdO stretch), 825-s, 812-s, 727-s (C-H oop bend); UVevis
(MeOH) lmax nm: 202, 241, 341; Mass: m/z [MþH]þ ¼ 268.0.
4-NDM-2′-HC: 1H NMR(400 MHz, CDCl3)
d
, ppm ¼ 13.21 (s, 1H,
-OH), 7.92 (d, 1H, J ¼ 8 Hz, H-6), 7.90 (d, 1H, J ¼ 16 Hz, H-9), 7.57 (d,
1H, J ¼ 16 Hz, H-8), 7.47 (d, 2H, J ¼ 8.2 Hz, H-11 and H-15), 7.35 (t,
1H, J ¼ 7.8 Hz, 8 Hz, H-4), 7.16 (d, 1H, J ¼ 7.8 Hz, H-3), 6.95 (t,
J ¼ 8 Hz,1H, H-5), 6.71 (d, 2H, J ¼ 8.2 Hz, H-12 and H-14) and 3.08 (s,
6H, -N(CH3)2);13C NMR(101 MHz, CDCl3)
163.46 (C2), 120.35 (C3), 135.63 (C4), 118.42 (C5), 129.36 (C6),
d
, ppm ¼ 120.36 (C1),
193.44 (C7, C]O), 118.47 (C8), 146.52 (C9), 122.41(C10), 130.86 (C11,

S. Kar et al. / Journal of Molecular Structure 1139 (2017) 294e302
299
Fig. 4. TGA/DTA curve for 4-NDM-TC.
3.3. Nonlinear optical properties
times urea [31] and in our case 4-NDM-TC showed activity 0.45
times urea which indicates that symmetric structures in thienyl
chalcones is essential for higher SHG efficiency.
3.3.1. SHG efficiency
The chalcones were evaluated for their SHG efficiency and the
values obtained from the SHG measurement are shown in Table 2. It
is known that the SHG values depend upon various factors for a
given compound. Some of the factors are conjugation, hydrogen
bonds, parallel stacking and pep interactions apart from the non-
centrosymmetric crystal structure [29].
3.3.2. Nonlinear optical susceptibilities measurements
The 3rd order NLO values obtained for the chalcones via the
Degenerate Four Wave Mixing technique are shown in Table 3.
When all the interacting waves in four wave mixing have same
frequency the process is said to be degenerate. This process results
from nonlinear index of refraction. DFWM provides information
about the magnitude and response of the third-order nonlinearity.
The strength of the fourth beam depends on a coupling constant
that is proportional to effective cð3Þ (third order nonlinear sus-
ceptibility). Thus measurements of the observed signal will yield
information about the cð3Þ tensor components of the medium. As a
technique, DFWM is the most frequently used method to charac-
terize third nonlinearity of novel materials. Although third order
NLO using z-scan has been reported for chalcones, we report the
first NLO measurements via DFWM for these set of chalcones.
In this study, we find that 3-Cl-40-HC is 1.37 times more active
than urea followed by 4-MO-20-HC with a relative gain of 1.30 [30].
Reduced activity is seen in 4-NDM-TC (0.45 times urea), 4-NDM-C
(0.35 times urea), 4-NDM-4'-BrC (0.33 times urea), and 4-Cl-40-HC
(0.25 times urea). It is interesting to note that among the chalcones
containing the N,N-dimethylamino group, all show SHG activity
other than 4-NDM-40-HC and 4-NDM-20-HC. This indicates that the
N,N-dimethylamino group is essential for SHG activity whereas
presence of hydroxyl along with the N,N-dimethylamino group
leads to inactivity. 3-Cl-40HC and 4-Cl-40-HC are isomers where
only the position of the eCl substituent is different. The role of the
position of the substituent is evident from the difference in the SHG
values, where 3-Cl-40-HC has the highest SHG efficiency (1.37 times
urea) while 4-Cl-40-HC has lowest observed SHG efficiency (0.25
times urea).
These chalcones possess a D-A-
p
-D type of arrangement. 4-
NDM-TC has highest NLO activity (c(3)
¼ 0.679) with respect
xxxx
to CS2 as the reference whereas others have lower c(3) values.
Firstly, examining the Chalcones containing the N,N-dimethy-
lamino substituent only, we have one fixed aldehyde side with the
eNMe2 group. Hence, the 4-NDM-C is the simplest of all the chal-
cones containing the eNMe2 group. In the ketone side we have 40-
OH, 40-Br, 20-OH substituents and also a different aromatic ketone,
i.e. 2-Acetyl thiophene. The chalcone resulting from 2-acetyl thio-
phene, 4-NDM-TC demonstrates the highest activity. Upon further
examination, it is observed that these substituents pump electrons
to the ring. Thus, we infer that substituents with þR effect decrease
the NLO activity. But the bromo substituent has eI effect also
because of which there is a sharp rise in the activity from 4-NDM-
40-HC to 4-NDM-40-BrC. The position of these functional groups is
para. On similar lines another study reports the third order NLO
values of three chalcones using the Z-scan technique where the
chalcones have fixed B ring and substituents vary on the A ring [32].
In the mentioned study the compound 4Br4MSP has a Rejc(3)j value
A thienyl chalcone named T-CHL-2T has shown a SHG value of
52 times that of urea which is attributed to its symmetrical struc-
ture. Whereas chalcone T-CHL-CAN showed lower activity of 0.27
Table 2
SHG efficiency of the chalcones.
Sample
SHG values vs urea
3-Cl-40-HC
1.37
1.30
0.45
0.35
0.33
0.25
0
4-MO-20-HC
4-NDM-TC
4-NDM-C
4-NDM-40-BrC
4-Cl-40-HC
4-NDM-40-HC
4-NDM-20-HC
4-MO-40-HC
of 2.27 ꢂ 10ꢁ22 m2/V2 and the compound 4N4MSP has a Rejc(3)
j
0
0
value of 2.36 ꢂ 10ꢁ22 m2/V2. In both 4Br4MSP and 4N4MSP, the eBr

300
S. Kar et al. / Journal of Molecular Structure 1139 (2017) 294e302
Table 3
Observed and Relative 3rd order NLO susceptibilities of the chalcones along with their measured refractive indices.
Sample
Refractive index
c(3)
(observed)
c(3)
(relative)
c(3)
(observed)
c(3)
(relative)
yxyx
xxxx
xxxx
yxyx
CS2
4-NDM-TC
4-NDM-C
4-NDM-20-HC
4-NDM-40-BrC
4-NDM-40-HC
4-MO-40-HC
4-MO-20-HC
4-Cl-40-HC
3-Cl-40-HC
1.620
1.351
1.342
1.346
1.332
1.365
1.342
1.463
1.343
1.345
16.57
9.718
6.940
5.946
5.244
3.805
3.013
2.950
2.457
2.245
1
10.030
5.971
5.495
4.717
4.114
3.652
3.013
2.333
2.344
2.145
1
0.679
0.523
0.440
0.406
0.274
0.233
0.218
0.182
0.166
0.688
0.656
0.589
0.466
0.399
0.233
0.291
0.293
0.268
Note: The order for c
(3) is 10ꢁ21 m2/V2.
and the eNO2 functional groups are present in the para (4th) po-
sition. The nitro group is a stronger electron withdrawing group as
compared to bromo, resulting in the higher Rejc(3)j value of
4N4MSP as compared to that of 4Br4MSP. As observed in our work
and also in the mentioned study, electron withdrawing group (-I or
eR effect) at the para position increase the NLO activity as
compared to an electron pumping substituent, the effect observed
in Fig. 5.
Secondly, we observe that all the molecules containing the N,N-
dimethylamino substituent have NLO susceptibilities higher than
the other molecules. This indicates that the N,N-dimethylamino
group owing to its higher þR effect increases NLO activity, followed
by the methoxy substituent, and the chloro substituent at last.
Overall, we can conclude that substituents with þR effect on the B-
ring increase the activity. A similar kind of work has also been re-
ported using the Z-scan method, supporting our claim that an
electron pumping group in the phenylene ring (B ring) increase
activity [33]. Hence, this study makes the role of substituents very
important in the 3rd order NLO activity, helping establish a certain
structure-activity relationship.
3.3.3. Computational studies
The molecules were built and minimized using GaussView
(3.09). The obtained output files were studied extensively. The
various calculations were determined [34] and the values obtained
are summarized in Tables 4 and 5 given below.
The predicted MO energy gap correlated with the observed NLO
values. It is observed that the sample 4-NDM-TC, with the highest
3rd order NLO susceptibilities has the lowest energy gap whereas
3-Cl-40-HC has the lowest 3rd order NLO susceptibilities with
relatively higher energy gap. This trend continues barring a few
exceptions. The plot of observed values vs the energy gap depicted
in Fig. 6 demonstrated a significant correlation with the R2 value of
0.9327. We know that the hardness or the softness of the molecule
is directly related to its reactivity. Here we have obtained a specific
trend being followed in case of the obtained hardness and softness
values. The hardness increases with decreasing 3rd order NLO
susceptibilities whereas the softness of the samples increase. 4-
NDM-TC has the lowest hardness of 0.07449 units and the high-
est softness of 6.71231 units while, 4-Cl-40-HC has the highest
hardness of 0.088895 units and the least softness of 5.624613 units.
Another feature to notice is that 4-NDM-TC also has the highest
static dipole moment. And also all the molecules containing the
N,N-dimethylamino substituent have higher dipole moments than
the other molecules. This is reflected in their higher third order NLO
susceptibilities and better SHG efficiency in most cases. This fact
helps us conclude that higher static dipole moments in molecules
lead to better activity.
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
These observations are from the calculations obtained from
isolated gaseous molecule where we do not observe any specific
trend in the second order hyperpolarisability values which is
directly related to the
c(3) values of the molecule. However, the
calculations in a solvent medium when done as in accordance with
the experimental studies in methanol as the solvent, returns a
change in the second order hyperpolarisability values. These values
4-NDM-4'-H-C
4-NDM-4'-Br-C
4-NDM-2'-H-C
Sample name
4-NDM-C
4-NDM-T-C
now follow a trend proportional to their
c(3) values. Barring 4-
NDM-40-BrC, the second order hyperpolarisability values for the
molecules obtained from the solvent phase calculations increase as
Fig. 5. Plot of c(3)xxxx of molecules containing N,N-dimethylamino substituent only.
Table 4
Various parameters obtained with respect to the molecular orbitals.
Sample
Energy gap in AU (MeOH)
Hardness in AU (MeOH)
Softness in AU (MeOH)
3-Cl-40-HC
0.17469
0.17444
0.17482
0.16698
0.15389
0.15044
0.15241
0.14813
0.14443
0.088825
0.088895
0.089280
0.089015
0.079290
0.076845
0.078280
0.078755
0.074490
5.629046
5.624613
5.600358
5.617031
6.305965
6.506604
6.387328
6.348803
6.712310
4-Cl-40-HC
4-MO-20-HC
4-MO-40-HC
4-NDM-40-HC
4-NDM-40-BrC
4-NDM-20-HC
4-NDM-C
4-NDM-TC

S. Kar et al. / Journal of Molecular Structure 1139 (2017) 294e302
301
Table 5
Parameters obtained with respect to polarizability in gaseous and solvent phase.
Sample
Static dipole moment
(Gas phase) debye
Second order hyperpolarisability
(Gaseous) debye-ang**3
Second order hyperpolarisability
(MeOH) Debye-ang**3
3-Cl-40-HC
2.5991
1.8861
2.4033
0.8405
2.4775
3.9909
3.6802
3.9622
4.3634
ꢁ10998.05024
ꢁ12445.73106
ꢁ11374.39172
ꢁ11603.24782
ꢁ13827.04074
ꢁ18869.80974
ꢁ13276.69886
ꢁ13204.40990
ꢁ13052.21288
ꢁ10640.09080
ꢁ10833.18972
ꢁ11411.69180
ꢁ11417.75892
ꢁ12993.25620
ꢁ19079.00120
ꢁ13565.89724
ꢁ13851.18242
ꢁ13933.13580
4-Cl-40-HC
4-MO-20-HC
4-MO-40-HC
4-NDM-40-HC
4-NDM-40-BrC
4-NDM-20-HC
4-NDM-C
4-NDM-TC
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
providing the TGA/DTA data. The authors acknowledge the valuable
inputs and help given by Sri C. Sai Manohar, Department of
Chemistry, SSSIHL and Sri Parth Gupta, Department of Chemistry,
IIT-Madras.
R² = 0.9327
Appendix A. Supplementary data
Supplementary data related to this article can be found at http://
dx.doi.org/10.1016/j.molstruc.2017.03.064.
0.17469 0.17444 0.17482 0.16698 0.15389 0.15044 0.15241 0.14813 0.14443
Calculated Energy Gap (a.u.)
References
Fig. 6. Plot of c(3)xxxx of molecules vs the calculated energy gap.
[1] R.L. Sutherland, Handbook of Nonlinear Optics, second ed., Dekker, New York,
1996.
[2] J.W. Perry, K. Mansour, I.Y.S. Lee, X.L. Wu, P.V. Bedworth, C.T. Chen, et al.,
Organic optical limiter with a strong nonlinear absorptive response, Science
273 (1996) 1533e1536.
[3] S. Dhanuskodi, T.C.S. Girisun, N. Smijesh, R. Philip, Two-photon absorption and
optical limiting in tris-thiourea cadmium sulphate, Chem. Phys. Lett. 486
(2010) 80e83.
[4] M. Sai Kiran, Benoy Anand, S. Siva Sankara Sai, G. Nageswara Rao, Second- and
third-order nonlinear optical properties of bis-chalcone derivatives,
J. Photochem. Photobiol. A Chem. 290 (2014) 38e42.
their
values and second order hyperpolarisability values.
Thus, a thorough in silico investigation of the molecules gives a
broad idea about the various physical parameters for the molecules,
enabling their correlation unto observed 3rd order NLO
susceptibilities.
c c(3)
(3) values also increase. 3-Cl-40-HC has the lowest
[5] B.T. Yin, C.Y. Yan, X.M. Peng, S.L. Zhang, S. Rasheed, R.X. Geng, C.-H. Zhou,
Synthesis and biological evaluation of a-triazolyl chalcones as a new type of
4. Conclusions
potential antimicrobial agents and their interaction with calf thymus DNA and
human serum albumin, Eur. J. Med. Chem. 71 (2014) 148e159.
[6] Z. Liu, L. Tang, P. Zou, Y. Zhang, Z. Wang, Q. Fang, L. Jiang, G. Chen, Z. Xu,
H. Zhang, G. Liang, Synthesis and biological evaluation of allylated and pre-
nylated mono-carbonyl analogs of curcumin as anti-inflammatory agents, Eur.
J. Med. Chem. 74 (2014) 671e682.
[7] B. Kupcewicz, A.A. Jarze˛cki, M. Małecka, U. Krajewska, M. Rozalski, Cytotoxic
activity of substituted chalcones in terms of molecular electronic properties,
Bioorg. Med. Chem. Lett. 24 (2014) 4260e4265.
[8] S. Shenvi, K. Kumar, K.S. Hatti, K. Rijesh, L. Diwakar, G.C. Reddy, Synthesis,
anticancer and antioxidant activities of 2,4,5-trimethoxy chalcones and ana-
logues from asaronaldehyde: structure-activity relationship, Eur. J. Med.
Chem. 62 (2013) 435e442.
[9] R. Shivahare, et al., Synthesis, structureeactivity relationships, and biological
studies of chromenochalcones as potential antileishmanial agents, J. Med.
Chem. 57 (2014) 3342e3357.
[10] V. Shettigar, et al., Crystal growth and characterization of new nonlinear
optical chalcone derivative: 1-(4-Methoxyphenyl)-3-(3, 4-dimethoxyphenyl)-
2-propen-1-one, J. Cryst. Growth 295 (2006) 44e49.
[11] Konstantinos Iliopoulos, et al., Nonlinear absorption reversing between an
electroactive ligand and its metal complexes, Opt. Express 23 (2012)
25311e25316.
[12] H.J. Ravindra, H.J. Ravindra, A. John Kiran, K. Chandrasekharan,
H.D. Shashikala, S.M. Dharmaprakash, Third order nonlinear optical properties
and optical limiting in donor/acceptor substituted 40-methoxy chalcone de-
rivatives, Appl. Phys. B 88 (2007) 105e110.
[13] A.I. Vogel, B.S. Furniss, Vogel's Textbook of Practical Organic Chemistry, fourth
ed., Longman, USA, 1989.
We have presented nine chalcones which have been prepared
by the Claisen-Schmidt condensation, characterized with spectro-
scopic techniques and one of the representative member has been
studied via single crystal XRD. Further its purity by thermal
profiling was studied using the TGA/DTA technique. The SHG and
NLO activities have been studied, with the NLO properties being
evaluated using the Degenerate Four Wave Mixing technique. We
also have established the effect of various substituents on the NLO
properties, thus establishing a structure-activity relationship never
done before using the DFWM technique. This study concludes that
in these chalcones electron withdrawing groups (-I or eR effect) on
the A-ring at the para (40) position increase the NLO activity as
compared to an electron pumping group. On the other hand sub-
stituents with þR effect on the B-ring increase the activity. These
chalcones have been evaluated extensively by in silico techniques to
obtain various parameters which are useful to predict different
activities and patterns which in turn help us to design molecules
with enhanced activities. The resonance of the computed and
experimental values shows the accuracy of the in silico calculations.
The NLO studies have indicated that these chalcones have potential
applications in optical switching, photonic devices, etc.
[14] SMART, SAINT, Software Reference Manuals. Versions 6.28a & 5.625, Bruker
Analytical X-ray Systems Inc, Madison, Wisconsin, U.S.A., 2001.
[15] G. M. Sheldrick, SHELXS97 and SHELXL Version 2014/7, http://shelx.uni-ac.
gwdg.de/SHELX/index.php.
[16] J. Giuliani, L. Goldberg, F. Von Batchelder, An evaluation of nonlinear optical
materials by the second-harmonic powder technique, in: DTIC Document,
1971.
[17] S. Kurtz, T. Perry, A powder technique for the evaluation of nonlinear optical
materials, J. Appl. Phys. 39 (2003) 3798e3813.
[18] G. Rivoire, Modern Nonlinear Optics, Part 1, Wiley, New York, 1993.
Acknowledgements
The authors are grateful to Bhagawan Sri Sathya Sai Baba,
Founder Chancellor, SSSIHL, for His constant inspiration. The au-
thors thank Dr. D Rajesh Babu, Department of Chemistry, SSSIHL for

302
S. Kar et al. / Journal of Molecular Structure 1139 (2017) 294e302
[19] J.P. Bourdin, Phu X. Nguyen, G. Rivoir, J.M. Nunz, Polarization properties of the
orientational response in phase conjugation, Nonlinear Opt. 7 (1994) 1e6.
[20] B. Sahraoui, Phu X. Nguyen, M. Salle, A. Gorgues, Electronic and nuclear
contributions to the third-order nonlinear optical susceptibilities of new p-N,
N0-dimethylaniline tetrathiafulvalene derivatives, Opt. Lett. 23 (1998)
1811e1813.
Academic & Professional London, 1987.
[29] K. Naseema, Vijayalakshmi Rao, K.V. Sujith, Balakrishna Kalluraya, Crystal
growth and characterization of an NLO organic crystal: N0-[(Z)-(4-
methylphenyl)methylidene]-4-nitrobenzohydrazide, Curr. Appl. Phys. 10
(2010) 1236e1241.
[30] Y. Goto, A. Hayashi, Y. Kimura, M. Nakayama, Second harmonic generation
and crystal growth of substituted thienyl chalcone, J. Cryst. Growth 108
(1991) 688e698.
[21] B. Sahraoui, G. Rivoire, Degenerate four-wave mixing in absorbing isotropic
media, Opt. Commun. 138 (1997) 109e112.
[22] R.G. Caro, M.C. Gower, Phase conjugation by degenerate four wave mixing in
absorbing media, IEEE J. Quantum Electron 18 (1987), 1376e1982.
[23] R.I.I. Dennington, et al., GaussView, Version 3.09, Semichem, Inc., Shawnee
Mission, KS, 2003.
[24] M.J. Frisch, et al., Gaussian 03, Revision C.02, Gaussian, Inc., Wallingford CT,
2004.
[25] R.M. Silverstein, F.X. Webster, D.J. Kiemle, Spectrometric Identification of
Organic Compounds, seventh ed., John Wiley & Sons, USA, 2005.
[26] D.L. Pavia, G.M. Lampman, G.S. Kriz, J.R. Vyvyan, Introduction to Spectroscopy,
fourth ed., Cengage Learning, USA, 2009.
[31] G. Nageswara Rao, et al., D-A-p-D Synthetic approach for thienyl chalcones e
NLO e a structure activity study, J. Photochem. Photobiol. A Chem. 324 (2016)
33e39.
[32] E.D. D’silva, G. Krishna Podagatlapalli, S. Venugopal Rao, S.M. Dharmaprakash,
Study on third-order nonlinear optical properties of 4-methylsulfanyl chal-
cone derivatives using picosecond pulses, Mater. Res. Bull. 47 (2012)
3552e3557.
[33] H.J. Ravindra, K. Chandrashekaran, W.T.A. Harrison, S.M. Dharmaprakash,
Structure and NLO property relationship in a novel chalcone co-crystal, Appl.
Phys. B 94 (2009) 503e511.
[27] P. Menezes, A. Jayarama, W.N. Seik, Synthesis, Crystal growth and charac-
[34] N. Günay, H. Pir, D. Avcı, Y. Atalay, NLO and NBO analysis of sarcosine-maleic
acid by using HF and B3LYP calculations, J. Chem. 2013 (2013), http://
dx.doi.org/10.1155/2013/712130.
terization of a D-p-A type novel organic nonlinear optical single crystal,
J. Cryst. Growth 402 (2014) 130e137.
[28] P.J. Haines, in: Thermal Analysis Principle; Applications and Problems, Blackie,