Study the effects of terminal side chain and –nitro group on mesomorphic behaviour of cinnamate-chalconyl based liquid crystal

Article abstract of DOI:10.1080/15421406.2016.1262672

The influence of the terminal side chain and lateral nitro on mesomorphism due to the flexibility and polarity of lateral group is investigated. A new homologues series is synthesized to accomplish this aim. The C₁ to C₃ homologue are nonmesomorphic, while the rest of the homologues exhibit enantiotropic nematic and smectic properties. The texture of the nematic mesophase is of threaded, Schlieren and droplets type. All these compounds were characterized by elemental analyses and spectroscopic techniques of FTIR and ¹H Nuclear magnetic resonance (NMR). The phase behaviour was studied by polarizing optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction techniques.

Full text of DOI:10.1080/15421406.2016.1262672

Molecular Crystals and Liquid Crystals
ISSN: 1542-1406 (Print) 1563-5287 (Online) Journal homepage: http://www.tandfonline.com/loi/gmcl20
Study the effects of terminal side chain and –nitro
group on mesomorphic behaviour of cinnamate-
chalconyl based liquid crystal
Vinay S. Sharma & R. B. Patel
To cite this article: Vinay S. Sharma & R. B. Patel (2017) Study the effects of terminal side chain
and –nitro group on mesomorphic behaviour of cinnamate-chalconyl based liquid crystal, Molecular
Crystals and Liquid Crystals, 643:1, 1-12, DOI: 10.1080/15421406.2016.1262672
To link to this article: http://dx.doi.org/10.1080/15421406.2016.1262672
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Date: 24 February 2017, At: 10:27

MOLECULAR CRYSTALS AND LIQUID CRYSTALS
, VOL. , –
http://dx.doi.org/./..
Study the effects of terminal side chain and –nitro group on
mesomorphic behaviour of cinnamate-chalconyl based
liquid crystal
Vinay S. Sharma and R. B. Patel
Chemistry Department, K.K. Shah Jarodwala Maninagar Science College, Gujarat University, Ahmedabad,
Gujarat, India
ABSTRACT
KEYWORDS
Enantiotropic; liquid crystal;
nematic; smectic
The influence of the terminal side chain and lateral nitro on mesomor-
phism due to the flexibility and polarity of lateral group is investigated.
A new homologues series is synthesized to accomplish this aim. The
C1 to C3 homologue are nonmesomorphic, while the rest of the homo-
logues exhibit enantiotropic nematic and smectic properties. The tex-
ture of the nematic mesophase is of threaded, Schlieren and droplets
type. All these compounds were characterized by elemental analyses
1
and spectroscopic techniques of FTIR and H Nuclear magnetic reso-
nance (NMR). The phase behaviour was studied by polarizing optical
microscopy (POM), differential scanning calorimetry (DSC), and X-ray
diffraction techniques.
GRAPHICAL ABSTRACT
Introduction
Liquid crystal (LC) is an intermediate state of a matter in between the liquid and the crystal
behaving with some typical properties of a liquid as well as some crystalline properties. There
are many kinds of LC materials with different molecular structures, based on which LC can
be divided into three categories, that is, calamitic liquid crystal, bent-shape liquid crystal, and
discotic liquid crystal. Calamitic LC materials are widely used in a flat-panel displays, smart
windows, laser, and other photonics. Liquid crystalline (LC) chalconyl ester derivatives play
dual role useful in LC devices and pharmaceutical preparation and therapeutical treatment to
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 and Francis Group, LLC

2
V. S. SHARMA AND R. B. PATEL
cure diseases within definite range of concentration in solution state [1–10]. Liquid crystals in
the nematic group are most commonly used in production of liquid crystal displays (LCD) due
to their unique physical properties and wide temperature range. In the nematic phase, liquid
crystal molecules are oriented on average along a particular direction. By applying an electric
or magnetic field the orientation of the molecules can be derived in a probable approach [11–
17]. This mechanism provides the basis for LCDs.
In our previous work, we have proposed homologous series that consist of three phenyl
rings bonded through vinyl carboxy and chalconyl central groups as well as varying left n-
alkoxy terminal end group and a fixed tail part at right side ended group [18]. Therefore, in
present investigation is planned with a view to understand and establish the effects of tail
group (-OC16H33) and lateral group (-NO2) on molecular structure of LC properties of ther-
motropic mesomorphism. Number of homologous series or LC materials have been reported
in which ester-chalconyl linkage group is present to date [19–24], Group efficiency order and
structure relation with mesomorphism will be derived.
Experimental
Synthesis
Trans 4-n- alkoxy cinnamic acids (A) prepared by modified method of Dave et al. and Vora
et al. [25]. (E)-3-(4-(hexadecyloxy) phenyl)-1-(4-hydroxy-3-nitrophenyl) prop-2-en-1-one
(B) was prepared by usual established method [26]. Esters were synthesized by a method
reported in literature [27]. Thus, the Chalconyl - Ester homologue derivatives were filtered,
washed with sodium bicarbonate solution, dried and purified till constant transition temper-
atures using an optical polarizing microscope equipped with a heating stage. Alkyl halides
(R-Br), 4-hydroxy benzaldehyde, 4-hydroxy 3-nito acetophenone, dicyclohexyl carbodimide
(DCC), Dimethyl amino pyridine (DMAP), Anhydrous K2CO3, Malonic acid, KOH, DCM,
Ethanol, Acetone required for synthesis were used as received except solvents which was dried
and distilled prior to use. The synthetic route to a series is shown in Scheme 1.
Characterization
Representative homologues series were characterised by elemental analysis, Infrared spec-
troscopy, 1H NMR spectra. IR spectra were recorded by Perkin-Elmer spectrum GX, 1HNMR
spectra were recorded on Bruker using CDCl3 as solvent. Microanalysis was performed on
Perkin-Elmer PE 2400 CHN analyzer (Table 1). Transition temperature and LC properties
(Textures) were determined using an optical polarising microscopy equipped with heating
stage (Table 2). Texture image of some homologues for nematic phase were determined
by miscibility method (Table 3). Decomposition temperatures (Table 4) were determined
using of Shimadzu DSC 60 differential Scanning Calorimeter with a heating rate of 5 to
10.0°C min−1. Thermodynamic quantities enthalpy (ꢀH) and entropy (ꢀS = ꢀH/T) are
qualitatively discussed.
Analytical data
IR spectra in cm−1 for butyloxy, hexadecyloxy & octadecyloxy derivatives
–
–
– –
Butyloxy: 640 Polymethylene ( CH2 )n of –OC10H21, 823(–C H def. m di-substituted-
–
–
– –
Para), 734 Polymethylene ( CH2 ) of –OC16H33, 937 (–C H def. hydrocarbon), 1510-1450
–
– – – – –
(N O Str bands) 1056 and 1018( C O ) Str, 1373 and 1303 and 1249, 1165 ( C O Str in

MOLECULAR CRYSTALS AND LIQUID CRYSTALS
3
Scheme . Synthesis route of series-.
– – –
– = –
– =
–(CH2)n chain, 1427 and 1465 ( C H def. in CH2), 1512 ( C C )str, 1602 ( C O group),
–
–
– –
1728 ( COO ester group), 2848 and 2914 ( C H str in CH3).
–
–
–
–
Hexadecyloxy: 740 Polymethylene ( CH2 )n of –OC16H33, 648 Polymethylene ( CH2 )n
–
– – – –
of C16H33 817(–C H def. m di-substituted-Para), 972 (–C H def. hydrocarbon), 1530-
– – – – –
1470 (N-O Str. bands), 1064 ( C O ) Str, 1365 and 1249, 1165 ( C O str in –(CH2)n chain,
– – – – =
– = –
1365 and 1450 ( C H def. in CH2), 1510 ( C C )str, 1604 and 1681 ( C O group), 1735
– –
–
–
( COO ester group), 2854 and 2924( C H str in CH3).
–
–
– –
Octadecyloxy: 734 Polymethylene ( CH2 )n of –OC18H37, 831(–C H def. m di-
– –
–
substituted-Para), 941 (–C H def. hydrocarbon), 1540- 1460 (N O Str bands), 1056
( C O ) Str, 1373 and 1303 and 1249, 1165 ( C O str in –(CH2)n chain, 1388 and 1468
– – –
– –
– – –
– = –
– =
–
–
( C H def. in CH2), 1512 ( C C )str, 1604 and 1681 ( C O group), 1735 ( COO ester
group), 2850 and 2920 ( C H str in CH3).
– –
Table . Elemental analysis for () pentyloxy () hexyloxy () decyloxy, and () dodecyloxy derivatives.
Elements % found
H
Elements % Calculated
H
Sr. no.
Molecular formula
CHNO
C
N
C
N

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.



C
HNO
HNO
CHNO
C

4
V. S. SHARMA AND R. B. PATEL
Table . Transition temperature in °C by POM.
Transition temperatures in °C
Sr.no
R = n-alkyl group
Cr
Smectic
Nematic
Isotropic













C
C
C
C
C
C
C
C
C
C
C
C
C
·
·
·
·
·
·
·
·
·
·
·
·
·
—
—
—
—
—
—
—
·
—
—
—
—
.
.
.
.
.
.
.
.
.
—
—
—
—
.
.
.
.
.
.
.
.
.
.
.
.
.
·
·
·
·
·
·
·
·
·
·
·
·
·
—
—
·
.
.
.
.
.
.
.
.
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
Table . Texture of nematic phase of C, C, C, C by miscibility method.
Sr. no.
Homologue
Texture

C
Threaded
Schlieren
Threaded
Schlieren



C
C
C
Table . Transition temperature (°C) and enthalpy (J g−) and entropy change (J g−k−) by DSC
measurement.
Homologues
or Comp.
Heating scan Cooling scan
Transition
(°C)
(°C)
ꢀH (-Jg−
)
ꢀH (Jg−
)
ꢀS(J g−k−
)
ꢀS(J g−k−
)
C5
Cr-SmC
SmC-N
N-I
Cr-SmC
SmC-N
N-I
Cr-SmC
SmC-N
N-I
Cr-SmC
SmC-N
N-I
—

>


>


>


—

—


—


—


—
—
.
—
.
.
—
.
.
—
.
.
—
—
.
—
.
.
—
.
.
—
.
.
—
—
.
—
.
.
—
.
.
—
.
.
—
—
.
—
.
.
—
.
.
—
.
.
—
C14
C16
C18
>
1HNMR spectra in CDCl3 in δ ppm for methoxy, pentyloxy, octyloxy, decyloxy, and
dodecyloxy derivative
–
Methoxy: 0.88 (t, 3H, CH3 of –C16H33), 1.26 (m, 2H n-poly methylene groups
–
of OC16H33),1.75 (m, 2H, n-poly methylene groups of –OC16H33), 1.29 (P, 10 H of –OC16H33
– – – –
–
–
=
group), 3.81 (s, O CH2 CH3-of –OCH3), 4.06 (t, 3H, O CH2 CH2-of –OC16H33), 6.93-
–
–
=
–
–
–
–
6.95 (d, 1H, CO CH CH ), 7.53-7.55 (d, 1H, CO CH CH ), 7.28-7.31 (d, 1H,

MOLECULAR CRYSTALS AND LIQUID CRYSTALS
5
–
=
–
–
–
=
–
–
CH CH COO ), 6.50 (d, 1H, CH CH COO ), 6.94-6.92 & 7.62-7.62 (d, 4H, left side
phenyl ring), 7.74 & 8.58, 8.41 (3H, central phenyl ring), 7.62-7.61 & 6.95-6.92 (d, 4H, termi-
nal phenyl ring).
–
Pentyloxy: 0.88-0.90 (t, 6H, CH3 of –OC5H11 & –OC16H33), 1.26 (m, n-poly methy-
lene groups of -OC16H33), 1.31 (q, 8H, CH2 of –OC5H11 & –OC16H33), 1.29 (P, 10 H
–
of –OC5H11 & –OC16H33 group), 1.75 (m, n-poly methylene groups of –OC5H11), 3.5-
–
–
– –
–
–
–
&
3.6 (s, OCH2 CH2-of-OC12H25), 4.06 (t, 6H, O CH2 CH2-of –OC5H11
OC16H33),
–
–
=
–
–
=
–
7.54-7.56 (d, 1H, CO CH CH ), 8.30-8.32 (d, 1H, CO CH CH ), 7.62-7.64 (d, 1H,
–
=
–
–
–
=
–
–
CH CH COO ), 6.30 (d, 1H, CH CH COO ), 6.94-6.91 & 7.60-7.62 (d, 4H, left side
phenyl ring), 7.72 & 8.58, 8.41 (3H, central phenyl ring), 7.60-7.61 & 6.95-6.92 (d, 4H, termi-
nal phenyl ring).
–
Octyloxy: 0.88 (t, 6H, CH3 of –OC8H17 & –OC16H33), 1.2-1.3 (m, n-poly methy-
lene groups of –OC8H17
group), 1.74-1.76 (m, n-poly methylene groups of –OC8H17
–
OC16H33), 1.29 (P, 10 H of –OC8H17 & –OC16H33
&
–
&
OC16H33), 4.06 (t, 6H,-
–
–
–
–
=
–
O CH2 CH2-of –OC8H17 & –OC16H33), 6.92-6.95 (d, 1H, CO CH CH ), 7.52-7.55 (d,
–
–
=
–
–
=
–
–
–
=
–
–
1H, CO CH CH ), 7.28-7.31 (d, 1H, CH CH COO ), 6.50 (d, 1H, CH CH COO ),
6.94-6.90 & 7.61-7.62 (d, 4H, left side phenyl ring), 7.74 & 8.58, 8.41 (3H, central phenyl ring),
7.62-7.60 & 6.95-6.92 (d, 4H, terminal phenyl ring).
–
Decyloxy: 0.88 (t, 6H, CH3 of –OC10H21 & –OC16H33), 1.2-1.5 (m, n-poly methy-
lene groups of –OC10H21 & -OC16H33), 1.29 (P, 10 H of –OC10H21 & –OC16H33 group),
1.31 (q, 8H of 1.80 (m, n-poly methylene groups of –OC10H21 & –OC16H33), 4.06
– –
–
–
–
–
=
–
(t, 6H, O CH2 CH2-of –OC10H21 & –OC16H33), 6.93-6.95 (d, 1H, CO CH CH ),
–
–
=
–
–
=
–
7.53-7.55 (d, 1H, CO CH CH ), 7.28-7.31 (d, 1H, CH CH COO ), 6.50 (d, 1H,
–
=
–
–
CH CH COO ), 6.94-6.92 & 7.62-7.62 (d, 4H, left side phenyl ring), 7.74 & 8.58, 8.40
(3H, central phenyl ring), 7.62-7.61 & 6.94-6.92 (d, 4H, terminal phenyl ring).
–
Dodecyloxy: 0.87 (t, 6H, CH3 of –OC12H25 & –OC16H33), 1.2-1.5(m, n-poly methy-
lene groups of –OC12H25 & -OC16H33), 1.80 (m, n-poly methylene groups of –OC12H25
–OC16H33), 1.29 (P, 10 H of –OC12H25 & –OC16H33 group), 1.31 (q, 8H of 1.80 (m, n-poly
– –
&
–
–
methylene groups of –OC12H25 & –OC16H33), 4.06 (t, 6H, O CH2 CH2-of -OC12H25 & –
–
–
=
–
–
=
–
OC16H33), 6.93-6.95 (d, 1H, CO CH CH ), 7.53-7.55 (d, 1H, CO CH CH ), 7.28-7.31
–
=
–
–
–
=
–
–
(d, 1H, CH CH COO ), 6.50 (d, 1H, CH CH COO ), 6.94-6.92 & 7.62-7.62 (d, 4H,
left side phenyl ring), 7.74 & 8.58, 8.41 (3H, central phenyl ring), 7.62-7.61 & 6.95-6.92 (d,
4H, terminal phenyl ring).
Result and discussion
POM investigation
From the POM measurements, we have found that the 4-hydroxy nitro derivative of chal-
cone (m.p. 71°C, yield 74%) do not possess liquid crystalline phase however by the linking
with trans cinnamic acid that display mesomorphism property. Mesomorphic character com-
mences at C5 homologue and continued up to last C18 homologue as enantiotropically manner
and shows smectic as well as nematic mesophase. C1 to C4 homologues are does not show LC
phase due to their high crystallising tendency. This compounds are directly converted from
solid phase to liquid phase without exhibit liquid crystalline property. In present case, we
–
have represents the effect of polarity or polarizability of laterally nitro group ( NO2) and flex-
–
ibility due to end side chain ( OC16H33) in liquid crystalline behaviour. The phase diagram
is shown in Fig. 1, which is plotted against the number of carbons atoms present in n-alkyl

6
V. S. SHARMA AND R. B. PATEL
Figure . Phase diagram of series by POM.
chain of left n-alkoxy terminal end groups versus the transition temperatures of homologues
as observed and determined using an optical polarizing microscope equipped with a heat-
ing stage. Solid-isotropic curve follows a zigzag way of rising and falling as series is increased
with number of methylene unit linked in it and inclusive descending and slightly increases
at dodecyloxy homologue of the present homologues series. The smectic to nematic tran-
sition curve drop away with slightly ascends at C12 homologue and descends continue with
C18 homologue, respectively. Nematic-isotropic phase transition curve shows descending ten-
dency and ascending at C12 homologue, it behaves due to fairly abnormality from dodecyloxy
to octadecyloxy derivative. Both the transition curve indicated odd-even effect. The meso-
morphic properties are varying from homologue to homologue in same series because of
added methylene group in left side of the n-alkyl chain containing n-alkoxy terminal side
chain. The presence of odd-even effect diminishes as series is ascended beyond octyloxy
derivatives.
Texture image shown in Fig. 2, for C10 homologue, the schlieren texture image at 166°C,
(b) Smectic C phase for C12 homologue at 148°C, (c) Smectic C phase for C8 homologue
at 160°C, (d) Threaded type nematic phase of C18 homologue at 120°C during heating and
cooling conditions respectively. C16, C14, C5 homologue display nematic phase mention in
Fig. S1 (Supplementary data).

MOLECULAR CRYSTALS AND LIQUID CRYSTALS
7
Figure . POM image of (a) C homologue, (b) C homologue, (c) C homologue, (d) C homologue.
The absence of lamellar packing of molecules in their solid crystal lattices at solid form (C1
to C4) due to unsuitable magnitudes of intermolecular anisotropic forces of lateral attractions
which hinders to maintain sliding moving layered of molecules in their floating condition
on the surface under exposed thermal vibrations. As increasing the chain which sliding
moving the arrangement of molecules closeness to each other to cause smectic mesophase
(C6 to C18) homologue. The exhibition of nematic mesophase formation for definite range of
temperature by C5 to C18 homologue is attributed to the suitable magnitudes of anisotropic
forces of intermolecular attractions due to fittest magnitudes of molecular polarity and
polarizability, permanent dipole-moment across long molecular axis with increasing chain,
dispersion forces etc. as a consequence of favourable molecular rigidity and flexibility which
facilitated statistically parallel orientational order of molecules in floating condition on
the surface to cause nematic mesophase (threaded and Schlieren type) in the presence
of thermal energy. The changing magnitudes of mesogenic properties from homologue
to homologue in the same series is due to the changing number linked methylene unit
which made variations in the gradual variations in molecular rigidity and flexibility due
to long chain at terminal side. The phase sequence of comp.C10 during cooling condition
shown in Fig. 3. The nematic phase starts at 166°C from isotropic mass, than it cooled
to convert into nematic droplets and applying further cooling, movement of sliding layer
and it transform into smectic mesophase which on more cooling switch into solid crystal
phase.
Textures of nematic phase in presently prepared series are threaded, schlieren, while the
smectic phase are of the type of smectic C. Thermal stabilities for smectic and nematic are
157.0°C and 175.33°C, respectively, whose observed total mesophaselength (Sm+N) at 10–
42°C.

8
V. S. SHARMA AND R. B. PATEL
Figure . Phase sequence of C homologue at heating condition by POM
DSC study
The thermal behaviour of novel homologues series were examined by using DSC measure-
ment. In Fig. 4, C18 homologue, heating condition first endothermic peak at 110°C, which
indicates the presence of SmC. That was further confirmed by POM. While second peak
observed at 138°C shows nematic phase. However, at cooled condition, the endothermic peak
observed at 104°C and 132°C. In C14 homologue, first endothermic peak at 110°C and second
peak at 140°C during heating stage, while in cooling stage two peak trace at 132°C and 105°C.
That was confirmed by POM analysis and that indicates the mesophase obtained enantiotropi-
cally. C16 homologue, during heating first endothermic peak observed at 105°C confirmed the
Figure . DSC measurement (A) C homologue, (B) C homologue, (C) C homologue, (D) C homologue.

MOLECULAR CRYSTALS AND LIQUID CRYSTALS
9
Figure . (a) DSC measurement of C homologue.
presence of SmC and second endothermic at 132°C, that confirm the nematic mesophase, At
cold condition mesophase confirm by POM investigation that shows two peaks are at 125°C
and 102°C which confirmed the presence of mesophase smectic as well as nematic that was
also confirmed by POM study enantiotropically manner. (D) C5 homologue, one endother-
mic peak observed at 168°C, that indicates the presence of only nematic phase, again at cooled
condition, the single peak was traced at 155°C, which was confirmed by POM at late com-
mencement of mesophase at 182°C, heating and cooling condition.
Transition temperature obtained by DSC analysis at heating and cooling condition and the
value of enthalpy and entropy is mention in Table 4. Molecules of every homologue randomly
oriented in all possible directions with high order of disorder or entropy (ꢀS = ꢀH/T) beyond
isotropic temperature and the enthalpy value (ꢀH). But, at cooled condition, the same from
and below isotropic temperature, the mesophase is persisted to appear reversibly at the high
temperature at observed during heating condition. The mesophase obtained in this present
series is enantiotropically smectogenic and nematogenic manner respectively. In Fig. 5, LC
phase is confirmed by DSC analysis with trace two endothermic peak which confirmed the
presence of smectic and nematic phase at heating and cooling condition.
Powder X-ray diffractometer study
In order to correlate the results of the DSC and POM, we have performed powder X-ray
diffraction. The molecular arrangement and the presence of smectic phase is confirmed by
using XRD measurement. Heated compound at its transition temperature. In Fig. 6, the graph-
ical representation of proposed molecular packing of smectic C phase. The XRD of C7 homo-
logue at 148°C. Two diffraction peaks are obtained at low angles (d: 33.08 A° and 6.92A°)
show in Fig. 7.
The changing mesogenic behaviours from varying left side chain in the same series is
attributed due to changing number of methylene units linked with it, which causes variations
in the magnitudes of the total molecular part including tailed group with presence of –NO2
group at lateral side with effect of its polarity and polarizability to induce mesophase and
molecular rigidity unaltered because rest of the molecular part including tailed end remains
unchanged throughout the novel synthesized homologues series. Some LC properties eval-
uated from thermotropic data of presently investigated novel series-1 with compared with
structurally similar analogues series X [28] as mentioned below Fig. 8.

10
V. S. SHARMA AND R. B. PATEL
Figure . Proposed molecular packing of the Sm C phase in present series.
Figure . XRD diffractogram of Compound C homologue at °C.
Figure . Structurally similar analogous series.
In Fig. 8, the homologous series-1 is presently investigated and series-X is taken for com-
parison, same in linearity except series-1 contain one more vinyl linkage group and nitro
group at lateral side. Therefore the magnitudes of molecular rigidity and flexibility differ-
–
=
–
–
ing from homologue with presence of vinyl carboxy ( CH CH COO-) in series-X and lat-
eral side (-NO2), however, in series-X, carboxy linkage group ( COO-) and no any lateral

MOLECULAR CRYSTALS AND LIQUID CRYSTALS
11
Figure . Space filling diagram of series- and series-X.
group. Thus, variations in mesomorphic properties like thermal stability and mesophase-
lengths, commencement of mesophase etc. will depend upon the magnitudes of changing
features of homologous series 1, and series X taken under comparative study. Figure 9 shows
the space filling diagram of series 1 and series X respectively. Series 1 is more linear as com-
pare to series X, it is differ with ethylene linkage with carboxy linking group in cinnamates
with middle phenyl ring, while in series X carboxy group linked with first and second phenyl
ring with absence of nitro group.
Nematic thermal stability of present series-1 is the greater than series-X under compari-
son. Nematic mesophase instigates from C6 homologue for a series-X, while smectic property
is totally absent. The exhibition of nematic mesophase in addition to smectic phase in case of
present synthesized series-1 is attributed to the ortho substituted –NO2 lateral group, which
rises molecular polarity and polarizability. Though broaden of molecule in which, reducing
at end to end fascinations, but, the magnitudes of intermolecular attractions through polar-
izability increases to such an extent that, the environmental situation favours sliding layered
molecular arrangement at Cr-Sm transition temperature and then, statistically parallel orien-
tational order of molecules in fluctuating condition between Sm-N and N-I transition tem-
peratures. Thus, the more polarizable series-1 and X are missing smectogenic character and
additional polarizable series-1 to convince with lateral substitution facilitated exhibition of
smectic property in addition to nematic property.
Conclusions
In summary, we have synthesized a series of chalconyl esters linked groups with flexible
aliphatic side chain with benzene core, which exhibit smectogenic and nematogenic prop-
erty enantiotropically manner, the mesomorphism was confirmed by POM, DSC, and pow-
der XRD. The degree of mesomorphism is higher with introduced lateral side by nitro group
as compare to series-X.
Acknowledgments
Authors acknowledge thanks to Dr. R. R. Shah, principal of K. K. Shah Jarodwala Maninagar Sci-
ence College, Ahmedabad. Authors are also thankful to Dr. A. V. Doshi, Ex-principal of M.V.M.
Science College - Rajkot for his constant support, inspirations and help, as and when needed during
the course of present investigation. Authors thank to Centre of Excellence, Rajkot for the spectral
services.

12
V. S. SHARMA AND R. B. PATEL
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