Synthesis, characterization, and mesomorphic investigation of vinyl ester-substituted chalcones and effect of lateral ?NO2 and ?OCH3 group

Article abstract of DOI:10.1080/15421406.2016.1272814

A novel homologous series of α-4-(4′-n-alkoxy cinnamoyloxy) phenyl β-2″-nitro, 3″–4″ di methoxy benzoyl ethylenes, H_{2n + 1}CnO?C₆H₄?CH?CH?COO?C₆H₄?CO?CH?CH?C₆H₂(NO₂) (OCH₃)₂ (n = 1–8, 10, 12, 14, 16, 18) has been synthesized. All these compounds have been characterized by suitable spectroscopic techniques. C₁ homologue is nonmesogenic, while C₂ homologue shows enantiotropic nematogenic property and the rest of the homologous (C₃?C₁₈) displayed enantiotropically smectogenic plus nematogenic phase. Phase transition temperatures and textures of the LC phase were determined by an optical polarizing microscopy (POM) equipped with a heating stage. The mesomorphic properties of these compounds were confirmed by differential scanning calorimetry (DSC) analysis.

Full text of DOI:10.1080/15421406.2016.1272814

Molecular Crystals and Liquid Crystals
ISSN: 1542-1406 (Print) 1563-5287 (Online) Journal homepage: http://www.tandfonline.com/loi/gmcl20
Synthesis, characterization, and mesomorphic
investigation of vinyl ester-substituted chalcones
and effect of lateral ‒NO2 and ‒OCH3 group
Vinay S. Sharma & R. B. Patel
To cite this article: Vinay S. Sharma & R. B. Patel (2017) Synthesis, characterization,
and mesomorphic investigation of vinyl ester-substituted chalcones and effect of lateral
‒NO2 and ‒OCH3 group, Molecular Crystals and Liquid Crystals, 643:1, 241-251, DOI:
10.1080/15421406.2016.1272814
To link to this article: http://dx.doi.org/10.1080/15421406.2016.1272814
Published online: 23 Feb 2017.
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Date: 24 February 2017, At: 10:40

MOLECULAR CRYSTALS AND LIQUID CRYSTALS
, VOL. , –
http://dx.doi.org/./..
Synthesis, characterization, and mesomorphic investigation
of vinyl ester-substituted chalcones and effect of lateral
–
–
NO and OCH group
Vinay S. Sharma and R. B. Patel
Chemistry Department, K. K. Shah Jarodwala Maninagar Science College, Gujarat University, Ahmedabad,
Gujarat, India
ABSTRACT
A
KEYWORDS
novel homologous series of α-4-(4ꢀ-n-alkoxy cinnamoy-
Liquid crystal; mesomorphic;
smectic; nematic;
enantiotropic
loxy) phenyl β-2ꢀꢀ-nitro, 3ꢀꢀ–4ꢀꢀ di methoxy benzoyl ethylenes,
– – = – – – – = –
2n+1CnO C6H4 CH CH COO C6H4 CO CH CH C6H2(NO2) (OCH3)2
H
(n = 1–8, 10, 12, 14, 16, 18) has been synthesized. All these compounds
have been characterized by suitable spectroscopic techniques. C1
homologue is nonmesogenic, while C2 homologue shows enan-
tiotropic nematogenic property and the rest of the homologous
–
(C3 C18) displayed enantiotropically smectogenic plus nematogenic
phase. Phase transition temperatures and textures of the LC phase were
determined by an optical polarizing microscopy (POM) equipped with a
heating stage. The mesomorphic properties of these compounds were
confirmed by differential scanning calorimetry (DSC) analysis.
1. Introduction
Liquid crystals are matter in a state that has properties between those of conventional flow
like liquid and solid crystals. For instance, a liquid crystal may flow like a liquid, but its
molecules may orient in a crystal like way [1–4]. Liquid crystals can be divided into ther-
motropic, lyotropic, and metallotropic phases. Presently, we have focus on thermotropic
liquid crystals in which, phase transition into liquid crystal phase as temperature changed
[5–10]. Liquid crystals of the nematic type are most commonly used in the production of
liquid crystal displays (LCD) due to their unique physical properties and wide temperature
range and stability [11–14]. Liquid crystals are fascinating functional materials and are impor-
tant in the field of advanced materials such as electro-optical devices, laser addressed devices,
passive block filters, and devices based on thermochromism such as fever indicators, gadgets,
reflective-type LCDs, field effect transistors, and sensors [15]. They are indispensable in bio-
logical systems and are becoming part of high-tech processes [16]. The mesomorphic behav-
ior of an organic compound is basically dependent on its molecular architecture in which a
slight change in the molecular geometry brings about considerable change in its mesomor-
phic properties. Detailed studies on liquid crystals have led to empirical rules which include
the effect of chemical constitution in the nematogenic and smectogenic mesophases [17, 18].
CONTACT Vinay S. Sharma
vinaysharma@gmail.com
Science College, Gujarat University, Ahmedabad , Gujarat, India.
Chemistry Department, K. K. Shah Jarodwala Maninagar
Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/gmcl.
©  Taylor & Francis Group, LLC

242
V. S. SHARMA AND R. B. PATEL
C. V. Yellamaggad et al. reported the bent-core unsymmetrical dimers based on cholesteryl
ester and chalconyl moiety, which enhances the biaxiality and chirality of the system [19].
A number of chalcone having reported to exhibit a broad spectrum of antibacterial, anti-
fungal, antiulcer, antimalarial, antitumor, anticancer, anti-inflammatory, and antitubercular.
–
=
–
–
The presence of α, β-unsaturated functional group in chalcone ( CH CH CO ) is responsi-
ble for the anti-microbial activity, which can be altered depending upon the type of substituent
present on the aromatic rings [20–24]. Thus, the object of present work is to synthesize and
studied the mesomorphism in chalconyl vinyl ester linkage group and also the effect of lat-
eral nitro group and methoxy group on LCs. Many series of liquid crystalline compounds
containing heterocyclic groups have been synthesized due to their usefulness in wide applica-
tion electrical, optical, biological, and medical field [25, 26]. R. Gopalakrishnan et al. reported
chalcone based single crystals, growth, and comparison of two new enone shifted chalcones
and their NLO behaviour [27]. Tandel et al. studied the chain chalconyl polymers compounds
to exhibiting threaded type nematic phases [28]. Doshi et al. reported homologous series
based on chalconyl-ester and chalconyl-vinylester linkage group [29–31]. Sadashiva et al.
reported the synthesis and mesomorphic properties of some ester of trans-4-n-alkoxy cin-
namic acid and trans-4-n-alkoxy-α-methyl cinnamic acid with branched chain alkyl tails
exhibiting ferroelectric and anti-ferroelectric phases [32]. Prajapati et al. studied some homol-
ogous series consisted cinnamate linkage group and show its effect on mesomorphic proper-
ties of liquid crystalline compounds [33, 34]. Bhoya et al. reported chalconyl vinyl-ester link-
ing group and studied the effect of bromo group at a lateral position on the mesomorphic
property [35].
In order to explore further factors which govern the thermal stability and mesophase-
length of liquid crystals with vinyl-ester containing chalconyl linking group based on three
benzene core rings. Here, in present study, we compare the effect of linkage group on LC
behaviour, thermal stability, mesophaselength and commencement of mesophase in present
synthesized series with structurally similar reported series. Recently, our group reported
various isomeric and nonisomeric chalconyl ester linking group based homologous series
[36–40].
2. Experimental
2.1. Synthesis
The target chalconyl vinylester compounds were synthesized as outlined in Scheme 1. Trans
4-n-alkoxy cinnamic acids (A) were prepared by the modified method of Dave and Vora
et. al. [41]. (3-(4, 5-dimethoxy-2-nitrophenyl)-1-(4-hydroxy phenyl)-prop-2-en-1-one) (B)
was prepared by the usual established method [42]. In the final step, the coupling of the
compound (A) and (B) is done by Steglich esterification to yield the target product [43].
Thus, chalconyl-ester homologue derivatives were filtered, washed with sodium bicarbon-
ate and dilute sodium hydroxide solution, dried and purified till constant transition temper-
atures appear, using an optical polarizing microscope equipped with a heating stage. Alkyl
halides, 4-hydroxy acetophenone, 4-hydroxy benzaldehyde, 4,5-dimethoxy-2-nitro benzalde-
hyde, malonic acid, dicyclohexyl carbodimide (DCC), dimethyl amino pyridine (DMAP),
dichloro methane, ethanol, pyridine, piperidine, Acetone required for the synthesis was used
as received except solvents which was dried and distilled prior to use. The molecular struc-
tures of the target products and the intermediates were confirmed by spectroscopic analysis
and elemental analysis.

MOLECULAR CRYSTALS AND LIQUID CRYSTALS
243
Scheme . Synthetic route of target compounds.
2.2. Reaction scheme
2.3. Characterization
Representative homologues series were characterised by elemental analysis, infrared spec-
1
troscopy, and H NMR spectra. IR spectra were recorded by Perkin-Elmer spectrum GX,
1HNMR spectra were recorded on Bruker using CDCl3 as solvent (400 MHz). Micro-
analysis was performed on Perkin-Elmer PE 2400 CHN analyzer shown in Table 1. Tex-
ture image of some homologues for the nematic phase was determined by the miscibility
method (Table 2). Transition temperature (Table 3) and LC properties (textures image) were
Table . Elemental analysis for () ethoxy, () propyloxy, () butyloxy, () pentyloxy and () hexyloxy
derivatives.
Elements % found
H
Elements % Calculated
H
S.
No. Molecular formula
CHON
C
N
C
N

.
.
.
.
.
.
.
.
.
.
.s
.
.
.
.
.
.
.
.
.
.
.
.
.
.




C
HON
.
.
.
.
CHON
CHON
CHON
.

244
V. S. SHARMA AND R. B. PATEL
Table . Texture of Nematic Phase of C, C, C, C by miscibility method.
S. No.
Homologue
Texture

C
C
C
C
Rodlike
Rodlike
Threaded
Threaded



determined by using an optical polarising microscopy (POM) equipped with the heating
stage. Decomposition temperatures were determined using of Shimadzu DSC 60 differen-
tial Scanning Calorimeter with a heating rate of 5–10.0°C min−1. Thermodynamic quantities
enthalpy (ꢀH) and entropy (ꢀS = ꢀH/T) are qualitatively discussed. The mesophaselength
and thermal stability of mesophase were determined by POM study and the enthalpies for all
newly chalconyl vinylester-based liquid crystals compound were determined by differential
scanning calorimetry (DSC) analysis.
2.4. Analytical data
IR Spectra in cm−1
Chalcone (B): 3624 ( OH str.-bonded), 3016 ( C H- str in CH3), 941 ( C H- def. hydro-
– – – – – – –
:
–
– –
– –
carbon), 1076 and 1022( C O ) str, 1253, ( C H– def. in CH2), 1175 ( O CH3), 1430 (–
– = – = – –
NO2 group), 1512 ( C C–)str, 1662 ( C O group), 2812 and 2927 (aromatic C H str.),
–
=
–
960 (trans, CH CH ) group.
Propyloxy (C3): 810 Polymethylene group of ( CH2 )n of OC3H7, 820 ( C H- def. di-
– – – – – – –
–
–
–
– –
substituted), 930 ( C H- def. hydrocarbon), 1022 ( C O ) str, 1253 ( C O) str in –(CH2)n
– – – –
– = –
chain, 1405 ( C H- def. in CH2), 1440 (-NO2 group), 1175 ( O CH3), 1540 ( C C )str,
– = – –
–
–
–
1630 ( C O group), 1720 ( COO ester group), 2812 and 2927 (aromatic C H str. OCH3
= –
–
=
–
group), 3140, 3170 ( C H str.), 970 (trans, CH CH ) group.
–
–
–
– –
Pentyloxy (C5): 780 Polymethylene group of ( CH2 )n of OC5H11, 820 ( C H- def.
– – – – – – –
di-substituted), 931 ( C H- def. hydrocarbon), 1076 ( C O ) str, 1225 ( C O) str in
– – – –
–(CH2)n chain, 1405 ( C H- def. in CH2), 1175 ( O CH3), 1440–1446 (-NO2 group),
– = –
– =
–
–
= –
1545 ( C C )str, 1640 ( C O group), 1730 ( COO ester group), 2830 and 2928
– –
–
–
=
–
(aromatic C H str. OCH3 group), 3240, 3170 ( C H str.), 970 (trans, CH CH )
group.
Table . Transition temperature in °C by POM.
Transition temperatures in (°C)
S. no.
R = n-alkyl group
Cr
Smectic
Nematic
Isotropic
.













C
C
C
C
C
C
C
C
C
C
C
C
C
·
·
·
·
·
·
·
·
·
·
·
·
·
—
—
—
—
—
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
·
·
·
·
·
·
·
·
·
·
.
·

MOLECULAR CRYSTALS AND LIQUID CRYSTALS
245
–
–
–
– –
Dodecyloxy (C12): 760 Polymethylene group of ( CH2 )n of OC12H25, 820 ( C H-
– – – – – – –
def. di-substituted), 932 ( C H- def. hydrocarbon), 1024 ( C O ) str, 1245 ( C O) str
– – – –
in –(CH2)n chain, 1405 ( C H- def. in CH2), 1175 ( O CH3), 1446 (-NO2 group), 1540
– = – – =
–
–
( C C )str, 1660 ( C O group), 1740 ( COO ester group), 2840 and 2930 (aromatic
– –
–
–
–
=
–
C H str. OCH3 group), 3130 (=C H str.), 975(trans, CH CH ) group.
–
–
–
– –
Tetradecyloxy (C14): 741 Polymethylene group of ( CH2 )n of OC14H29, 820 ( C H-
– – – – – – –
def. di-substituted), 931 ( C H- def. hydrocarbon), 1076 ( C O ) str, 1253 ( C O) str
– – – –
in –(CH2)n chain, 1175 ( O CH3), 1405 ( C H- def. in CH2), 1441 (-NO2 group), 1540
( C C )str, 1640 ( C O group), 1730 ( COO ester group), 2830 and 2927 (aromatic
C H str. OCH3 group), 3130 (=C H str.), 960 (trans, CH CH ) group.
– = –
– =
–
–
– –
–
–
–
=
–
1H NMR spectra in CDCl3 in δ ppm:
–
Chalcone (B): 3.84 (s, 6H, 2 ( OCH3)2 group, 7.70 (1H, d, J = 17Hz, = CH–Ar), 7.50 (1H,
–
–
–
d, J = 17Hz, CO CH = ), 6.80 (s, 1H, OH group), 6.92 (d, 2H, first phenyl ring), 7.44 (d,
2H, first phenyl ring), 8.02 (s, 1H, second phenyl ring), 7.47 (s, 1H, second phenyl ring).
–
–
–
–
Propyloxy (C3): 0.90 (t, 3H, CH3 of OC3H7), 1.72 (q, 2H, of OC3H7), 3.83 (6H,
2( OCH3)2, 4.06 (t, 2H, O CH2 of OC3H7), 7.05 (d, 1H, CO CH CH ), 8.54 (d, 1H,
CO CH CH ), 7.44 (d, 1H, CH CH COO ), 6.26 (d, 1H, CH CH COO ), 6.94 &
7.61 (d, 4H, left side phenyl ring), 7.51 & 8.14 (d, 4H, central phenyl ring), 7.04 & 7.72 (d, 2H,
–
– –
–
=
–
–
=
–
–
–
=
–
–
–
–
–
=
–
–
terminal phenyl ring).
–
–
–
Octyloxy (C8): 0.88–0.90 (t, 3H, CH3 of OC8H17), 1.29–1.31 (m, 6H of OC8H17), 1.74
–
–
–
– –
–
–
–
=
(t, 2H, OC8H17), 3.83 (6H, ( OCH3)2), 4.06 (t, 3H, O CH2 of OC8H17), 7.06 (d, 1H,
–
–
=
–
–
=
–
–
–
CO CH CH ), 8.56 (d, 1H, CO CH CH ), 7.44 (d, 1H, CH CH COO ), 6.26 (d,
1H, CH CH COO ), 6.84 & 7.61 (d, 4H, left side phenyl ring), 7.51 & 8.14 (d, 4H, central
phenyl ring), 7.04 & 7.71 (d, 2H, terminal phenyl ring).
–
=
–
–
–
–
–
Decyloxy (C10): 0.88–0.90 (t, 3H, CH3 of OC10H21), 1.29–1.31 (m, 6H of OC10H21),
– – –
1.74 (t, 2H, OC10H21), 1.31 (q, 2H, OC10H21), 3.83 (6H, ( OCH3)2), 4.06 (t, 3H, O CH2
–
–
–
–
–
–
=
–
–
–
=
–
of OC10H21), 7.06 (d, 1H, CO CH CH ), 8.56–8.58 (d, 1H, CO CH CH ), 7.43 (d,
1H, CH CH COO ), 6.26 (d, 1H, CH CH COO ), 6.84 & 7.61 (d, 4H, left side phenyl
ring), 7.52 & 8.16 (d, 4H, central phenyl ring), 7.04 & 7.71 (d, 2H, terminal phenyl ring).
–
=
–
–
–
=
–
–
–
–
–
Dodecyloxy(C12): 0.88–0.90 (t, 3H, CH3 of OC12H25), 1.26–1.29 (m, 14H of OC12H25),
– – –
1.31 (q, 2H, OC12H25), 1.74 (t, 2H, OC12H25), 3.83 (6H, ( OCH3)2), 4.06 (t, 3H, O CH2
–
–
–
–
–
–
=
–
–
–
=
–
of OC12H25), 7.06 (d, 1H, CO CH CH ), 8.56 (d, 1H, CO CH CH ), 7.44 (d, 1H,
CH CH COO ), 6.26 (d, 1H, CH CH COO ), 6.82 & 7.64 (d, 4H, left side phenyl ring),
7.51 & 8.14 (d, 4H, central phenyl ring), 7.04 & 7.70 (d, 2H, terminal phenyl ring).
–
=
–
–
–
=
–
–
3. Result and discussion
The synthetic route for the preparation of chalcone and trans 4-n-alkoxy cinnamic acid and
the target compounds α-4-[4ꢀ-n-alkoxy cinnamoyloxy] benzoyl-β-2ꢀꢀ-nitro, 4ꢀꢀ-5ꢀꢀ-dimethoxy
phenyl ethylenes is outlined in Scheme 1. In the present study, we have synthesized total 13
homologous (C1 to C8, C10, C12, C14, C16, C18). The mesomorphic properties of synthesized
novel compounds were characterized and investigated by DSC and POM.
3.1. DSC analysis
DSC is a valuable method for the detection of phase transitions. It yields quantitative results.
In the present study, DSC data of two homologous are mention in Fig. 1, which helps to fur-
ther confirm the mesophase appeared during POM investigation. C18 homologue reveals two

246
V. S. SHARMA AND R. B. PATEL
Figure . DSC curves of compound C and C homologous.
separate endothermic peaks at 98.26°C and 140.8°C on heating condition, which indicates the
presence of SmC and nematic mesophase. While on cooling condition, again two peaks were
trace at 86.34°C and 141.8°C, respectively. The similar phase behaviour was obtained for C16
homologue, first endothermic peak traced at 95.48°C and second endothermic peak observed
at 143.7°C, while on the cooling stage again two endothermic peaks appeared at 94.72°C and
141.4°C. which was further confirmed by POM analysis.
3.2. POM investigation
As a preliminary investigation, the mesophases exhibited by present series were examined
by using a polarising optical microscope. The samples were sandwich between a glass slide
and a cover slip. All the compounds of the series show mesomorphism except C1 homo-
logue which displayed the nonmesogenic property. In present synthesized series, the nematic
mesophase commences from C2 to C18 homologue and the smectic phase commences from
C3 to C18 homologous, respectively. Compound C2 to C18 shows enantiotropically LCs prop-
erty. In addition, compound C2 shows only nematic phase and compound C3 to C18 displayed
smectic as well as nematic phase enantiotropically manner. Transition temperatures (Table 3)
determined by optical polarization microscope and the phase diagram was plotted against the
transition temperature versus the number of carbon atoms present in n-alkyl chain of the left
–
n-alkoxy terminal end group ( OR).
The phase diagram shows I/Cr–M, Sm–N and N–I transition curve drawn by linking like
or related transition points as mention in Fig. 2. The I/Cr–M curve falling up to C3 homo-
logue and then ascends at C4 homologue and continued to decreased at C6 homologue and
again reaching maxima at C7 homologue. The odd–even effect is present in the I/Cr–M tran-
sition curve mentioned the in the phase diagram. The Sm–N transition curve initially falls at
C4 homologue and rising to C5 homologue, this is due to the presence of the odd–even effect
and then continued to decrease up to C10 homologue. The Sm–N transition curve slightly
increases at C12 to C14 homologue because of the effect of abnormality and decreasing transi-
tion curve from C16 to C18 homologue due to the number of methylene units increase which
inducing molecule to more polar and flexible. The N–I phase transition curve descending
at C5 homologue and ascends at C6 homologue and reaching maxima at C7 homologue and
again descends at C8 homologue and rising up to C10 homologue and then gradually decreased
up to last homologues. The odd and even parity of carbon present at C5 to C6 and C7 to
C8 in the N–I transition curve. While increasing number of carbon it behaves due to fairly

MOLECULAR CRYSTALS AND LIQUID CRYSTALS
247
Figure . Phase diagram of present series.
abnormality from decyloxy to octadecyloxy derivative. The mesogenic properties are vary-
ing from homologue to homologue in same series because of numbers of methylene group
–
–
( CH2 )n added in left side of alkoxy terminal side chain group.
On cooling the isotropic mass on a slide, the nematic mesophase observed and on applying
further cooling the nematic mesophase is reappeared to the smectic C phase in present series.
A Smectic C mesophase with rod-like texture is revealed for compound C6 in the heating and
cooling cycle on the basis of POM mention in Fig. 3(a). Compound C14 shows nematic type
droplets at 138°C on the cooling condition. Compound C16 displayed mosaic type smectic
A phase at nearly 96°C in the cooling cycle and further increasing temperature up to 142°C,
SmA mesophase transfer into the nematic phase. This is due to the flexibility of the layers
leads to more distortions within the molecules to floating on the surface with statistically
parallel orientational order within the definite range of temperature to exhibiting nematogenic
character. C8 homologue shows the typical texture image of the smectic C phase at 136°C on
the cooling cycle.
Compound C1 directly transformsfrom the solid phase to the isotropic phase without
showing LCs property and on cooling condition solidification occurs from isotropic mass
without display any LC phase. The nonmesomorphic property of C1 homologue attributed
–
to the presence of short alkyl spacer ( OCH3) at left side chain and become less flexible as
compared to other homologous in present series. The LC properties of newly synthesize com-
pounds are changing from varying left side chain in the same series as a result of changing
its molecular structure from lower homologue to higher homologue and keeping rest of right
–
side laterally substituted –NO2 and two sides substituted OCH3 group.
Nonmesomorphic chalcone linking with Trans 4-n-alkoxy cinnamic acid, as a result
increases the molecular length, permanent dipole moment across the axis, dispersion forces,
dipole-dipole interaction and polarizability of molecule with left side alkyl chain and lateral
–
attractions due to the presence of nitro group and OCH3 group which increase the polarity of
molecule to induce mesophase. Which disalign the molecules of all the homologues of a series
except C1 at an angle ninety degree or less than ninety degree under the control of exposed
thermal vibration as a consequence of molecular rigidity and flexibility [44]. In the previous
study, we reported that chalconyl-vinylester based liquid crystalline compounds shows good
–
–
=
–
biologically and fungal activity [23]. It has been studied that CO CH CH linkage group is

248
V. S. SHARMA AND R. B. PATEL
Figure . Microphotographs of the compounds (a) rod-like texture image of C at °C in the heating cycle;
(b) nematic droplets type texture image of C at °C in the cooling cycle; (c) mosaic texture of C at °C
in the cooling cycle; (d) typical texture image of C homologue at °C in the cooling cycle.
–
–
less conductive to induce mesomorphism as compared to benzoate ( COO ) and cinnamate
–
=
–
–
( CH CH COO ) group.
The liquid crystal property of newly homologous series-1 is compared with the other struc-
turally similar series-X [45] and series-Y [46] as shown in Fig. 4. Homologous series X and Y
chosen for comparison and the novel homologous series 1 is similar in respect of three phenyl
–
=
–
–
rings inbuilt with one central linking groups CH CH CO and the presence of left n-alkoxy
Figure . Structurally similar series.

MOLECULAR CRYSTALS AND LIQUID CRYSTALS
249
Figure . Space filling diagram of structurally similar series.
–
side chain present in ( OR) left terminal end group. Series-1 and series-X having vinyl-ester
linking group as compared to series-Y. They also differ in respect of the lateral groups in the
terminal or lateral positions on third phenyl ring. Therefore, the observed variations in their
mesomorphic properties and the degree of mesomorphism can be attributed to the differing
features of series 1, X and Y. The molecular length to breadth ratio, intermolecular end-to-
end and lateral attractions by substituted group and molecular polarizability of compounds is
increased by the presence of more polar lateral groups.
The geometrical shapes of molecules are linear rod like with the presence of lateral group
in series-1, -X, -Y mention in Fig. 5. The linearity and width of molecules in series-1, -X are
more as compared to series-X. The highest width of compounds in series-1as compared to
series-X and series-Y, due to the presence of three lateral groups. In addition, the presence of
–
=
–
–
=
–
–
ethylene ( CH CH ) unit in ( CH CH COO ) group in both series-1, -X, while in series-
–
–
Y, only carboxy ( COO ) group is present. In series-1, three lateral polar groups are present,
while in series-X, -Y only two methoxy groups are present.
Table 4 represents the thermal stability of series-1 with series-X and series-Y. In series-1
and series-Y, smectic and nematic phases are present and the absence of the smectic phase
in series-X respectively. In series-X, the smectic phase commences from C3 to C18 homolo-
gous, while in series-Y, it commences from C6 to C16 homologous. Total mesophaselength
(smectic + nematic) vary from maximum to minimum between C5 to C14 in series-1. N–I
thermal stability of series-X is higher as compared to series-1 and series-X, because of the
linearity of series-X is more than series-Y. Sm–N thermal stability of series-1 is higher as
compared to series-Y, for the reason that series 1 contains three highly polar groups -NO2
–
& OCH3, which increases its polarity and polarizability more as compared to series-X, -Y.
However, in series-X and series-Y it contains only one polar group. The presence of the double
Table . Average thermal stabilities in °C.
Series
Series-
Series-X
—
Series-Y
.
Sm–N or Sm–I
Commencement of smectic phase
.
(C – C)
C
–
(C C)
C
.
N–I
.
.
–
–
–
Commencement of nematic phase
(C C)
(C C)
(C C)
C
C
C
Total mesophase length in °C from
minimum to maximum
. to .
C C
. to .
C C
. to .
C C

250
V. S. SHARMA AND R. B. PATEL
bond in vinyl ester group can cause the isomerism and arrangement of atoms in space may
operate and create such an extent of noncoplanarity of molecules that smectic mesophase
is observed. Molecular rigidity is also changed from homologue to homologue and series to
series due to the presence of two different central bridges and vibrations cause by lateral group.
–
=
–
–
All three homologous series-1, -X, -Y contain common chalconyl ( CH CH CO ) group.
This result suggests that the presence of chalconyl unit can act as stronger activating group
due to the presence of α, β-unsaturated ketone.
4. Conclusion
In summary, we have successfully synthesized a new homologous series based on chalconyl
–
–
=
–
–
=
–
–
( CO CH CH ) and vinyl ester ( CH CH COO ) linkage group. The present synthesized
series having left terminal alkoxy side chains (n = 1–8, 10, 12, 14, 16, 18) has been . The
lower member of the series (C1) shows the nonmesomorphic property and (C2) homologue
displayed only the nematic mesophase. While other members of the series (n = 3–8, 10, 12, 14,
16, 18) shows smectic as well as nematic property. We have also studied the effect of lateral
side group on the mesomorphic property and compare against previously reported similar
series. Present synthesized series exhibits good thermal stability and mesophaselength.
Acknowledgments
The authors acknowledge thanks to Dr. R. R. Shah, principal of K. K. Shah Jarodwala Maninagar Sci-
ence College, Ahmedabad. The authors also thank to Centre of Excellence, NFDD center Rajkot for the
analytical and spectral services.
References
[1] Reinitzer, F. (1888). Monatsh. Chem., 9, 421.
[2] Narmura, S. (2001). Displays, 22(1), 1.
[3] Kim, W. S., Elston, S. J., & Ranyes, F. P. (2008). Display, 29, 458.
[4] Glendenning, M. E., Goodby, J. W., Hird, M., Jones, J. C., Toyne, K. J., Slaney, A. J., & Minter, V.
(1999). Mol. Cryst. Liq. Cryst., 332, 321.
[5] Vora, R.A., & Dixit, N. (1980). Mol .Cryst. Liq. Cryst., 59, 63.
[6] Demus, D. (1988). Mol. Cryst. Liq. Cryst., 165, 45.
[7] Hird, M. (2005). Liq. Cryst. Tod., 4, 9.
[8] Imrie, C. T. (1999). Struct. Bond., 95, 149.
[9] Seed, A. J., Hird, M., Styring, P., Gleeson, H. F., & Mills, J. T. (1997). Mol. Cryst. Liq. Cryst., 299,
19.
[10] Hird, M., Toyne, K. J., Goodby, J. W., Gray, G. W., Minter, V., Tuffin, R. P., & Mc Donnell, D. G.
(2004). J. Mater. Chem., 14, 1731.
[11] Yelamaggad, C. V., Prabhu, R., Shanker, G., & Bruce, D. W. (2009). Liq. Cryst., 36, 247.
[12] Klein, C., Baranoff, E., Nazeeruddin, M. K., & Gratzel, M. (2010). Tetrahedron Lett., 51, 6161.
[13] Prajapati, A. K., & Bonde, N. L. (2009). Mol. Cryst. Liq. Cryst., 501, 72.
[14] Aldred, N. L., Vlachos, P., & Dong, D. (2005). Liq. Cryst., 32, 951.
[15] (a) Sago, K. K., & Fujita, A. (2007). Mol. Cryst. Liq. Cryst., 479, 151. (b) Chulson, K., Park, D. J., &
Kim, Y. B. (2007). Mol. Cryst. Liq. Cryst., 479, 81.
[16] (a) Seredyuk, M., Gasper, A. B., & Reiman, S. (2006). Chem. Mater., 18, 2513. (b) Stewart, G. T.
(2003). Liq. Cryst., 30, 541. (c) Stewart, G. T. (2004). Liquid Cryst., 31, 443.
[17] Singh, S. K., Singh, M. K., Singh, H. K., & Singh, B. (2016). Mol. Cryst. Liq. Cryst., 624, 77.
[18] Singh, H. K., Singh, S. K., Kumar, V., & Singh, B. (2013). Mol. Cryst. Liq. Cryst., 587, 1.
[19] Yelamaggad, C. V., Bonde, N. L., Ammathnadu, S. A., Doddamane, S. R., Prasad, S.K., & Prajapati,
A. K., (2007). Chem. Mater., 19, 2463.

MOLECULAR CRYSTALS AND LIQUID CRYSTALS
251
[20] Sashidhara, K. V., Rao, K. B., Kushwaha, P., Modukuri, R. K., Singh, P., Soni, I., Shukla, P. K.,
Chopra, S., & Pasupuleti, M. (2015). ACS Med. Chem. Lett., 6, 809.
[21] Gaikwad, P. P., Desai, M. T. (2013). Interna. J. Pharma Res. Rev., 2(12), 40.
[22] Jose, N., Leo, D. C., Rodrigues, J., Dominguez, N. G., Gut, J., & Rosenthal, P. J. (2005). J. Med.
Chem., 48, 3654.
[23] Sharma, V. S., & Patel, R. B., (2016). WSN, 54, 240.
[24] Sashidhara, K. V., Kumar, A., Kumar, M., Sarkar, J., & Sinha, S. (2010). Bio Org. Med. Chem. Lett.,
20, 7205.
[25] Nielsen, S. F., Larsen, M., Boesen, T., Schonning, K., & Kromann, H. (2005). J. Med. Chem., 48,
2667.
[26] Shah, D. R., Lakum, H. P., & Chikhalia, K. H. (2014). ILCPA, 17(2), 207.
[27] Ramkumar, V., Anandhi, S., Kannan, P., & Gopalakrishnan, R. (2013). Cryst. Eng. Comm., 15,
2438.
[28] Tandel, R. C., Gohil, J., & Patel, N. K. (2012). Res. J. Rec. Scis., 1, 122.
[29] Patel, R. B., & Doshi, A. V. (2011). Der Pharma Chemica., 3(2), 147.
[30] Chauhan, H. N., & Doshi, A. V. (2013). Mol. Cryst. Liq. Cryst., 570, 92.
[31] (a) Chaudhari, R. P., Chauhan, M. L., & Doshi, A. V. (2013). Mol. Cryst. Liq. Cryst., 575, 88. (b)
Patel, R. B., Patel, V. R., & Doshi, A. V. (2012). Mol. Cryst. Liq. Cryst., 552, 3. (c) Chauhan, H. N.,
Shah, R. R., & Doshi, A. V. (2013). Mol. Cryst. Liq. Cryst., 577, 36.
[32] Sadashiva, B. K., Ksthuraiah, N., Krishnaprasad, S., & Nair, G. C. (1998). Liq. Cryst., 24, 639.
[33] Prajapati, A. K., Thakkar, V., & Bonde, N. (2003). Mol. Cryst. Liq. Cryst., 393, 41.
[34] Prajapati, A. K., & Patel, H. N. (2007). Mol. Cryst. Liq. Cryst., 34, 903.
[35] Maheta, S. A., Bhola, G. N., & Bhoya, U. C. (2015). ILCPA, 8(1), 77.
[36] (a) Sharma, V. S., Solanki, R. B., Patel, P. K., & Patel, R. B. (2016). Mol. Cryst. Liq. Cryst., 625, 137.
(b) Solanki, R. B., Sharma, V. S., & Patel, R. B. (2016). Mol. Cryst. Liq. Cryst., 631, 107. (c) Sharma,
V. S., & Patel, R. B. (2016). Mol. Cryst. Liq. Cryst., 630, 162.
[37] (a) Sharma, V. S., & Patel, R. B. (2016). Mol. Cryst. Liq. Cryst., 633, 80. (b) Solanki, R. B., & Patel,
R. B. (2016). Mol. Cryst. Liq. Cryst., 634, 24. (c) Solanki, R. B., & Patel, R. B. (2016). Mol. Cryst.
Liq. Cryst., 634, 50.
[38] Sharma, V. S., Jain, B. B., Chauhan, H. N., & Patel, R. B. (2016). Mol. Cryst. Liq. Cryst., 630, 79.
[39] Sharma, V. S., & Patel, R. B. (2016). ILCPA Scipress, 64, 69.
[40] Sharma, V. S., & Patel, R. B. (2015). ILCPA Scipress, 60, 182.
[41] Dave, J.S., & Vora. R. A. (1970). In: Liquid crystals and ordered fluids, Johnson, J. F. & Porter R. S.
(Eds.), Plenum Press: New York, 477.
[42] Furniss, B. S., Hannford, A. J., Smith, P. W. G., & Tatchell, A. R. (Eds.). (1989).Vogel’s Textbook 245
of Practical Organic Chemistry (4th ed.), 563, Longmann Singapore Publishers Pvt. Ltd.: Singapore.
[43] Pinol, R., Ros, M. B., Serrano, J. L., & Sierra, T. (2004). Liq. Cryst., 31, 1293
[44] Bhola, G. N., Bhoya, U. C. (2016). Mol. Cryst. Liq. Cryst., 630, 188.
[45] Suthar, D. M., Doshi, A. A., & Doshi, A. V. (2013). Mol. Cryst, Liq. Cryst., 577, 51.
[46] Suthar, D. M., Doshi, A. A., & Doshi, A. V. (2013). Mol. Cryst, Liq. Cryst., 582, 79.