Mesomorphism dependence on molecular rigidity and substitution of same functional group on lateral or terminal position of tailed phenyl ring

Article abstract of DOI:10.1080/15421406.2016.1264234

Novel liquid crystal materials (LCs) of low temperature range (53°C to 75°C) have been synthesized through a series of chalconyl derivatives consisting of two phenyl rings bonded through a –CH?CH?CO? central bridge to study the effect of molecular structure on LC properties in general and with a focus on molecular rigidity. The novel homologues series (C₁ to C₁₈) consists of thirteen homologues with general formula RO?C₆H₄?CH?CH?CO?C₆H₄?OC₁₀H₂₁(n) (meta). The C₁, C₂, C₃ homologues are nonliquid crystals (NLC) and the rest of the homologues (C₄ to C₁₈) are either monotropic or enantiotropic liquid crystals. C₄ to C₆ homologues are enantiotropicnematic and the rest of the mesomorphic homologues are (C₇ to C₁₈) monotropicsmectic in addition to monotropicnematic character. Transition and melting temperatures including textures of homologues were determined by an optical polarizing (POM) microscopy equipped with a heating stage. Textures of a nematic phase are threaded or Schlieren, and that of the smectic phase are of the type Smectic A or C as judged directly from the heating top of the microscope. Thermal stability for smectic is very poor and of the nematic is (N-I) 69.3°C whose, total mesophase length ranges between 07.0 to 14.0°C at C₈ and C₄ homologues respectively.

Full text of DOI:10.1080/15421406.2016.1264234

Molecular Crystals and Liquid Crystals
ISSN: 1542-1406 (Print) 1563-5287 (Online) Journal homepage: http://www.tandfonline.com/loi/gmcl20
Mesomorphism dependence on molecular rigidity
and substitution of same functional group on
lateral or terminal position of tailed phenyl ring
Vinay S. Sharma & R. B. Patel
To cite this article: Vinay S. Sharma & R. B. Patel (2017) Mesomorphism dependence
on molecular rigidity and substitution of same functional group on lateral or terminal
position of tailed phenyl ring, Molecular Crystals and Liquid Crystals, 643:1, 178-187, DOI:
10.1080/15421406.2016.1264234
To link to this article: http://dx.doi.org/10.1080/15421406.2016.1264234
Published online: 23 Feb 2017.
Submit your article to this journal
Article views: 1
View related articles
View Crossmark data
Full Terms & Conditions of access and use can be found at
http://www.tandfonline.com/action/journalInformation?journalCode=gmcl20
Download by: [Fudan University]
Date: 26 February 2017, At: 23:25

MOLECULAR CRYSTALS AND LIQUID CRYSTALS
, VOL. , –
http://dx.doi.org/./..
Mesomorphism dependence on molecular rigidity and
substitution of same functional group on lateral or
terminal position of tailed phenyl ring
Vinay S. Sharma and R. B. Patel
Chemistry Department, Shri K. K Shah Jarodwala Maninagar Science College, Ahmedabad, Gujarat University,
Ahmedabad, Gujarat, India
ABSTRACT
KEYWORDS
Chalconyl ester; Liquid
crystals; Nematic; Smectic
Novel liquid crystal materials (LCs) of low temperature range (53°C to
75°C) have been synthesized through a series of chalconyl derivatives
=
–
–
consisting of two phenyl rings bonded through a –CH CH CO central
bridge to study the effect of molecular structure on LC properties in
general and with a focus on molecular rigidity. The novel homologues
series (C1 to C18) consists of thirteen homologues with general formula
–
–
=
–
–
–
RO C6H4 CH CH CO C6H4 OC10H21(n) (meta). The C1, C2, C3 homo-
logues are nonliquid crystals (NLC) and the rest of the homologues (C4
to C18) are either monotropic or enantiotropic liquid crystals. C4 to C6
homologues are enantiotropicnematic and the rest of the mesomorphic
homologues are (C7 to C18) monotropicsmectic in addition to monotrop-
icnematic character. Transition and melting temperatures including
textures of homologues were determined by an optical polarizing
(POM) microscopy equipped with a heating stage. Textures of a nematic
phase are threaded or Schlieren, and that of the smectic phase are of the
type Smectic A or C as judged directly from the heating top of the micro-
scope. Thermal stability for smectic is very poor and of the nematic is
(N-I) 69.3°C whose, total mesophase length ranges between 07.0 to
14.0°C at C8 and C4 homologues respectively.
Introduction
The importance of liquid crystals, which exist as a unique state between crystalline solid
and isotropic liquid is well known. [1] The mesomorphic state of chalconyl derivatives
is well exploited in thermography, LC devices, electronic display devices, pharmaceutical
preparations, as antifungal, antibacterial, antimalarial, anticancer etc. including agricul-
ture field [2–11]. The present investigation is to understand and establish the effect of
molecular structure on LC properties and LC behaviors [12–16] with special reference
to molecular rigidity induced by effective aromaticity of a molecules with same lateral
or terminal group bonded to tailed phenyl ring of a homologues series of chalcone:
–
=
–
–
–
RO C6H4.CH CH CO C6H4 OC10H21 (n) (meta). Present investigation involves the
synthesis of novel chalconyl derivatives and their characterization by thermal, analytical, and
spectral techniques using a polarizing optical microscopy (POM) equipped with heating stage
CONTACT Vinay S. Sharma
vinaysharma@gmail.com; R. B. Patel
Department, ShriK. KShahJarodwalaManinagarScienceCollege, Ahmedabad-, GujaratUniversity, Ahmedabad, Gujarat,
India.
roshanpatel@gmail.com
Chemistry
©  Taylor & Francis Group, LLC

MOLECULAR CRYSTALS AND LIQUID CRYSTALS
179
etc. Evaluated thermometric data will be interpreted and discussed in terms of molecular
rigidity [17–20]. Present investigation will be compared with structurally similar homologues
series to derive group efficiency order for smectic and nematic. Number of homologues series
of thermotropic LC have been reported till the date since from recognition of LC state [21–27].
Experimental
Synthesis
Alkylation of 4-hydroxy benzaldehyde to give 4-n-alkoxy benzaldehyde is carried out by
reported method [28]. 3-n-Decyloxy acetophenone is obtained by alkylation of 3-hydroxy
acetophenone by reported method [29]. Thus, the chalconyl homologue derivatives (C) were
prepared by usual established method [30]. Final products were collected and filtered, washed
with ethanol solution dried and purified till constant transition temperatures obtained using
an optical polarizing microscope, equipped with a heating stage. Alkyl halides, Acetone,
EtOH, KOH, 3-Hydroxy acetophenone, 4-Hydroxy benzaldehyde etc., required for synthesis
were used as received, except solvents which were dried and distilled prior to use. The
synthetic route to the series is shown below as Scheme 1.
Characterization
Representative homologues of a series were characterized by elemental analysis, Infrared spec-
1
1
troscopy, H NMR spectra. IR spectra were recorded on Perkin–Elmer spectrum GX, H
NMR spectra were recorded on Bruker using CDCl3 as solvent. Microanalysis was performed
on Perkin-Elmer PE 2400 CHN analyzer (Table 1). Transition temperature (Table 3) and LC
properties (Textures) were determined using an optical polarizing microscopy equipped with
heating stage and digital camera (POM). Texture images of nematic phase were determined
by a miscibility method (Table 2).
Scheme . Synthetic route to the series.

180
V. S. SHARMA AND R. B. PATEL
Table . Elemental analysis for (1) butyloxy (c) (2) hexyloxy (c) (3) decyloxy (c) and (4) dodecyloxy (c)
derivatives.
Elements % found
Elements % Calculated
Sr. No.
Molecular formula
CHO
C
H
C
H

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.



C
HO
HO
C
CHO
Analytical data
IR spectra in cm− for hexyloxy & octadecyloxy derivatives
–
–
–
Hexyloxy (C6): 2914 (C H str. of alkane), 2842 (C H str. of –(CH2 ) n group of –OC6H13
=
=
alkyl chain, 1660 (C O str. of chalconyl group), 1604 (C C str. of alkene in chalcone), 1510,
1543 (C C str. of aromatic ring), 999 (C H bending of alkene), 1178 (C-O str. of ether
linkage), 1288, 1246 (C-O str. of carbonyl (>CO) group), 770 Polymethylene ( CH2 ) of –
OC10H21, 675 Polymethylene ( CH2 ) n of –OC6H13, 823(–C H- def. m di-substituted-Para),
=
–
–
–
–
–
–
IR data confirms the molecular structure of comp. C6.
–
–
–
Octadecyloxy (C18): 2916 (C H str. of alkane), 2850 (C H str. of –(CH2 ) n group of –
=
=
OC18H37 group, 1660 (>C O str. of carbonyl group of chalconyl group), 1604(C C str. of
=
–
alkene), 1543 (C C str. of aromatic ring), 1004, (C H bending of alkene), 1199 (C-O str. of
–
–
ether linkage), 1250(C-O str. of carbonyl group), 771 Polymethylene ( CH2 ) of –OC10H21,
823 (–C H- def. m di-substituted-Para), IR data confirms the molecular structure of comp.
–
C18.
HNMRspectra in CDCl in δ ppm for propyloxy, butyloxy, hexyloxy, decyloxy &
dodecyloxy derivative
–
Propyloxy (C3): 0.88 (t, 6H, CH3 of polymethylene –C3H7 and –C10H21), 1.79(p, 10H,
–
–
–
–
–
–
–
–
CH3 CH2 CH2 CH2 CH2 –OC10H21), 1.28 (m, 15H –CH2 CH2 CH2 of –OC10H21),
–
–
–
–
–
1.31 (q, 8H, CH2 CH3 of –C3H7 and –C10H21), 4.06(t, 4H, OCH2 CH2 –C3H7 and –
–
=
–
C10H21), 7.59 (d, 2H, CH CH ), 7.44, 7.27 & 7.82 (4H, meta substituted phenyl ring), 7.56
& 7.97 (4H, phenyl ring with alkoxy chain). NMR data confirms the molecular structure of
comp. C3.
–
Butyloxy (C4): 0.88 (t, 6H, CH3 of –C4H9 and –C10H21), 1.80(p, 10H,
CH3 CH2 CH2 CH2 CH2 CH2 of –OC14H29), 1.28 (m, polymethylene 16H, –
CH2 CH2 CH2 of –OC4H9 and –OC10H21), 1.34 (q, 8H, CH2 CH3 of –C4H9 and –
C10H21), 4.05(t, 4H, OCH2 CH2 –OC4H9 and –OC10H21), 7.59 (d, 2H, CH CH ),7.43,
7.28 &7.83 (4H, meta substituted phenyl ring), 7.56 & 7.97 (4H phenyl ring), 6.95 & 7.62 (4H,
phenyl ring with alkoxy chain). NMR data confirms the molecular structure of comp. C4.
Hexyloxy (C6): 0.88 (t, 6H, CH3 of –C6H13 and –C10H21), 1.80 (p, 10H,
CH3 CH2 CH2 CH2 CH2 CH2 of OC6H13 and –OC10H21), 1.28 (m, polymethylene
–
–
–
–
–
–
–
–
–
–
–
–
–
–
=
–
–
–
–
–
–
–
–
Table . Texture of nematic phase of C, C, C, C by miscibility method.
Sr. No.
Homologue
Texture

C
C
C
C
Schlieren
Threaded
Threaded
Schlieren




MOLECULAR CRYSTALS AND LIQUID CRYSTALS
181
–
–
–
–
–
–
16H –CH2 CH2 CH2 of –OC6H13 and –OC10H21), 1.34 (q, 8H, CH2 CH3), 4.05(t, 4H,
–
–
–
–
=
OCH2 CH2 –OC6H13 and –OC10H21), 7.59 (d, 2H, CH CH ),7.43, 7.28 &7.83 (4H,
meta substituted phenyl ring), 7.56 & 7.97 (4H, phenyl ring), 6.95 & 7.62 (4H, phenyl ring
with alkoxy chain). NMR data confirms the molecular structure of comp. C6.
–
Decyloxy (C10): 0.88 (t, 6H, CH3 of –C10H21 and –C10H21), 1.80 (p, 10H,
–
–
–
–
–
–
CH3 CH2 CH2 CH2 CH2 CH2 of OC10H21 and –OC10H21), 1.28 (m, polymethy-
–
–
–
–
–
lene 16H, –CH2 CH2 CH2 of –OC10H21 and –OC10H21), 1.34 (q, 8H, CH2 CH3 of
–OC10H21 and –OC10H21), 4.05(t, 4H, OCH2 CH2 –OC10H21 and –OC10H21), 7.59 (d,
2H, CH CH ),7.43, 7.28 &7.83 (4H, meta substituted phenyl ring), 7.52 & 7.91 (4H, phenyl
ring), 6.98 & 7.64 (4H, phenyl ring with alkoxy chain). NMR data confirms the molecular
structure of comp. C10.
–
–
–
–
=
–
–
Dodecyloxy (C12): 0.88 (t, 6H, CH3 of –C12H25 and –C10H21), 1.80 (p, 10H,
–
–
–
–
–
–
CH3 CH2 CH2 CH2 CH2 CH2 of OC12H25 and –OC10H21), 1.28 (m, polymethylene
–
–
–
–
–
16H –CH2 CH2 CH2 of –OC12H25 and –OC10H21), 1.36 (q, 8H, CH2 CH3 of –
–
–
–
OC12H25 and –OC10H21), 4.05(t, 4H, OCH2 CH2 –OC12H25 and –OC10H21), 7.59 (d, 2H,
–
=
–
CH CH ),7.44, 7.45 &7.63 (4H, meta substituted phenyl ring), 7.63 & 7.27 (4H, phenyl
ring), 6.94 & 7.62 (4H, phenyl ring with alkoxy chain). NMR data confirms the molecular
structure of comp. C12.
Results and discussion
4-n-Alkoxy benzaldehydes and meta-substituted decyloxyacetophenone are nonliquid crystal
components. But on condensing them together induced mesomorphism (LC property) com-
mencing from C4 homologue as enantiotropically nematogenic and from C7 homologue as
monotropic smectogenic plus monotropic nematogenic. Thus, C4 to C18 mesomorphic homo-
logues which include, C4 to C6 homologues as enantiotropically nematogenic and C7 to C18
homologues as monotropically smectogenic plus nematogenic characters. Transition temper-
atures (Table 3) as determined by polarizing optical microscopy (POM) were plotted against
the number of carbon atoms present in n-alkyl chain (R) of –OR group and then Cr-N/I,
Table . Transition temperature in °C.
Transition temperatures in °C
Sr. no
R= n-alkyl group
Smectic
Nematic
Isotropic













C
C
C
C
C
C
C
C
C
C
C
C
C
—
—
—
—
—
—
—
—
.
.
.
(.)
(.)
(.)
(.)
(.)
(.)
(.)
.
.
.
.
.
.
.
.
.
.
.
.
.
—
(.)
(.)
(.)
(.)
(.)
(.)
(.)
() Indicates Monotropy.

182
V. S. SHARMA AND R. B. PATEL
Figure . Phase behaviors of series.
N-I/I-N, N-Sm transition curves are obtained on linking like or related points as depicted in
a phase diagram (Fig. 1).
Cr-N/I transition curve follow zigzag path of rising and falling with overall descending ten-
dency and behaved with normal manner. N-I or I-N transition curve, initially descended and
then negligibly ascended in deviating manner from C10 homologue to C12 homologue with
descending tendency up to C16 and finally ascended by eight degree; with exhibition of odd-
even effect from C4 to C9 or C10. N-Sm transition curve rises and then passes through maxima
at C12 homologue and then descended up to C16 or C18 with exhibition of odd-even effect
from C7 to C9 or C10. Thus, it behaved in normal manner. Interstate transition temperatures
and the degree of mesomorphism or LC properties are varied from homologue to homologue
in the same series. Thermal stabilities for smectic and nematic are low. Textures of nematic
phase are threaded or Schlieren and that of the focal conic smectic are fan shaped smectic A or

MOLECULAR CRYSTALS AND LIQUID CRYSTALS
183
smectic C. Analytical and spectral including thermal data supported molecular structures of
homologues.
The linking of two nonmesomorphic components viz. alkoxy aldehydes and acetophenone
increases molecular length to breadth ratio, the ratio of the polarity to polarizability, inter-
molecular dispersion forces and dipole-dipole interactions, permanent dipole moment across
the long molecular axis aromaticity etc. as a consequence of increasing molecular rigidity
and flexibility. However, the suitable magnitudes (not more or less) of anisotropic forces of
intermolecular cohesions and closeness as a result of favorable combined effect commences
from C4 member of a series. The nonmesomorphicity of C1 to C3 homologues is attributed
to their high crystallizing tendency arising due to low magnitudes of intermolecular dis-
persion forces and the low magnitudes of dipole-dipole interactions inducing unfavorable
molecular rigidity and flexibility which, hinders the disalignment of molecules neither to
ninety degree, nor to less than ninety degree on the floating surface, either in reversible or
irreversible manner; under the influence of exposed thermal vibrations, as to facilitate and
stabilize smectic or nematic phase. However, the molecules of homologues higher than C3
(i.e., C4 to C18) exhibited mesophase either reversibly or irreversibly to facilitate and stabilize
either only enantiotropicnematic (C4 to C6) or smectic plus nematic phase (C7 to C18) in
monotropic manner. The monotropic mesophase showing homologues on heating transform
into isotropic liquid without passing through LC state from and beyond isotropic temperature
at which, the molecules are randomly oriented in all possible directions with high order of
disorder or high entropy (ꢀS = ꢀH/T). But, on careful cooling the same, a thermodynamic
system under microscopic (POM) examination radiates heat energy towards surroundings
from system (C7 to C18) in irreversible manner and set the molecular organization related
to suitable magnitudes of anisotropic forces of intermolecular end to end as well as lateral
attractions to facilitate molecular arrangement with stastically parallel orientational order
and then with sliding layered order for definite range of temperature, called as mesophase
length, to induce first nematic from isotropic and then from nematic to smectic mesophase.
The exhibition of odd-even effect by mesogenic transition curves (N-I)/I-N and N-Sm) are
attributed to progressively added methylene unit at the n-alkyl chain “R” of –OR group
and then odd-even effect diminishes after merging of odd-even transition curves for higher
homologues (greater than C10) of longer n-alkyl chain “R” of –OR group; showing single
transition curve. The longer n-alkyl chain “R” of –OR group and –C10H21 (n) chain bonded
through oxygen atom at meta substituted lateral may coil, bend, flex or couple to lie with
major axis of the core structure of a molecule which causes uncertainty in the status of n-alkyl
chain. Consequently, the magnitudes of molecular rigidity and flexibility undergo modified
to more or less extent to cause deviation from normal expected behavior of transition curve
or curves in a phase diagram. The variations in mesogenic properties from homologue to
homologue in the same series is attributed to the varying molecular rigidity and/or flexibility
as occurred due to addition of carbon atom in n-alkyl chain “R”, lateral –C10H21(n) alkyl chain
as well as uncertainty in their unexpected and modified positional status. The thermometric
some properties of presently investigated novel series-1 are compared with the structurally
similar analogous series-X [31] as mentioned below in Fig. 2.

184
V. S. SHARMA AND R. B. PATEL
Figure . Structurally similar series.
A novel homologous series-1 of present investigation are identical with respect to flexi-
ble terminally situated –OR and –OC10H21 end or lateral groups for the same homologue
from series to series, which contributes to the total molecular flexibility. But they differ with
respect to total molecular rigidity by two and three aromatic phenyl rings as well as absent and
–
–
present smectogenic carboxy ( COO ) central bridge of series 1 and X respectively. Therefore
the vibrations in the mesomorphic (LC) properties, or mesogenic behaviors or the degree of
mesomorphism are depended upon the differing features of series 1 and X or more precisely
or specifically depended upon differing molecular rigidity or differing magnitudes of aro-
maticity between series-1 and X for the same homologue. Following Table 4 represents some
thermometric experimental data for series-1 and series-X under comparative study.
Careful observation of Table 4 show that,
r
Presently investigated novel homologous series 1 is smectogenic plus nematogenic,
whereas, a homologous series-X is only nematogenic with absence of smectogenic
character.
Smectogenic character commences from C7 homologue, but it does not commence till
the last member of series-X.
Nematic mesophase identically commences from C4 homologue of series 1 and X.
Thermal stability for smectic is very low or negligible for present novel series-1 and it
does not stabilize till the last C16 homologue of series-X under comparison.
Thermal stability of present novel series-1 is lower than a series-X.
r
r
r
r
r
Upper and lower mesophase lengths of series-1 are less than a series-X.
Table . Relative thermal stabilities in °C.
Series
Series-
Series-X
—
Sm-N or Sm-I
 or less than °C
–
Or N-Sm or Sm Cr
(C – C)
Commencement of Smectic phase
N-I or I-N
Commencement of
Nematic phase
C
.
.
(C – C)
C
(C – C)
C
Total mesophase length in °C
from lower to upper.
.°C to .°C
CC
. to .
C/CC

MOLECULAR CRYSTALS AND LIQUID CRYSTALS
185
Exhibition of smectogenic character in addition to nematic character by present novel
series-1 and absence of smectogenic character in series-X is attributed to the substitution of –
OC10H21 (n) flexible group at the tailed phenyl rings at meta lateral and para terminal position.
Meta substituted –OC10H21(n) group increases molecular polarizability relatively more than
para substituted –OC10H21 (n) to facilitate lamellar packing of molecules in crystal lattices
of homologues (C7 to C18) belonging to series-1 of present investigation, which on cooling
the isotropic mass in irreversible manner induces smectogenic character with monotropic
manner from C7 to C18 members of a series-1. Homologous series-X chosen for compara-
tive study is linear and lath like, in which end to end intermolecular attractions and closeness
are stronger than corresponding homologue of series-1. Which favors to induce nematogenic
molecular textures of mesophase and hinders to facilitate lamellar packing of molecules to
exclude the possibility of facilitation of smectogenic character. Early or late commencement
of smectic phase depends upon the favorable or unfavorable extent of molecular noncopla-
narity under the influence of exposed thermal vibrations. The extent of molecular noncopla-
narity due to meta or para position of same –OC10H21 (n) flexible group linked to tailed ended
phenyl ring causes the difference of the ratio of the intermolecular polarity to polarizability
distance and the permanent dipolemoment across the long molecular axis, dispersive forces
–
and dipolarity of C-X bonds etc., which positively or negatively affects the suitable mag-
nitudes of anisotropic forces of end to end and/or lateral attractions to commence smectic
or/and nematic phase. Therefore through irrespective of presence or absence of smectic phase,
the nematogenic mesophase commences from C4 homologue of series 1 and X. Thermal sta-
bility, the degree of mesomorphism of nematic and thermal resistivity against exposed ther-
mal vibrations related with suitable magnitudes of anisotropic forces responsible to induce
mesophase or mesophases as consequence of molecular rigidity; as occurred through num-
ber of aromatic rings present in a molecule and other favorable or unfavorable factors. But
the aromaticity and the molecular rigidity are the predominated factors which increase ther-
mal stability for nematic and total mesophase lengths (lower and upper) from series 1 to
X or thermal stability for nematic and mesophase lengths of series-X are higher than a
series-1.
Conclusions
r
A laterally substituted chalconyl homologous series consisted of two aromatic rings is
predominantly nematogenic and partly monotropically smectogenic whose mesogenic
transition temperatures are low below 100°C.
Mesomorphism is very sensitive and susceptible to molecular structure as a result of low
molecular rigidity or low aromaticity and lateral substitution.
Present investigation may be useful to mankind in LC devices to be operated at room
temperature or desired temperature using the knowledge of binary system. Also, chal-
conyl derivatives being bioactive molecules may be useful for the preparations of
pharmaceutical and agricultural products against the protection of corps, flowers, and
fruits.
r
r
r
Group efficiency order derived for smectic and nematic on the basis of (i) ther-
mal stability (ii) Early commencement of mesophase and (iii) total mesophase
lengths.
(i). Smectic
–
–
lateral OC10H21(n) > terminal OC10H21 (n)
Nematic

186
V. S. SHARMA AND R. B. PATEL
–
–
terminal OC10H21 (n) > lateral OC10H21(n)
(ii). Smectic
–
–
lateral OC10H21(n) > terminal OC10H21 (n)
Nematic
–
lateral OC10H21(n) = terminal –OC10H21 (n)
(iii). Total mesophase length
r
Present investigation raises and supports the conclusion drawn earlier.
Acknowledgments
Authors acknowledge thanks to Dr. R.R. Shah, principal and management of K. K. Shah Jarodwala
Maninagar Science College, Ahmedabad. Authors are also thankful to Dr. A.V. Doshi, Ex-principal of
M.V.M. Science and Home Sci. College-Rajkot for his constant support, inspirations, help, and valuable
comments and suggestions, as and when needed during the course of present investigation. Authors
also thank to Centre of Excellence Rajkot for the spectral and analytical 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., & Raynes, F. P. (2008). Displays, 29, 458.
[4] Hertz, E., Lavorel, B., & Faucher, O. (2011). Nature Photon., 5, 783.
[5] Singh, S. K., Singh, M. K., Singh, H. K., & Singh, B. (2016). Mol. Cryst. Liq. Cryst., 624(1), 77.
[6] Rajesh, G., Mansi, K., Srikant, K., Babasaheb, B., Nagesh, D., Kavita, S., & Ajay, C. (2008). Chem.
Pharm. Bull., 56, 897.
[7] Calliste, C. A., Bail, J. C. L., Trouilas, P., Proug, C., Chulia, A. J., & Duroux, L. J. (2001). Anticancer,
Res., 21, 3949.
[8] Imaran, T., Shahi, S., Ramtekem, V., & Syed, I. (2012). IJPRAS, 1(2), 6.
[9] Jain, U. K., Bhatia, R. K., Rao, A. R., Singh, R., Saxena, A. K., & Irun, S. (2014). Trop. J. Pharm.
Res., 13(1), 73.
[10] (a) Kumudini, M. Meepagala, & Schrader, K. K. (2014). J. Agric. Chem. Environ., 3, 89. (b)
Venkateswarlu, S., Marellapudi, S., Ramachandra, A., Krishnaraju, V., Trimurtulu, G., & Sub-
baraju, G. V. (2006). Indian J. Chem., 45, 252. (a) Shakil, N. A., Singh, M. K., Sathiyendiram,
M., Kumar, J., & Padaria, J. C. (2013). Eur. J. Med. Chem., 59,120. (b) Lianghao, P., Liu, C. L.,
Huang, W., Wang, Y. Z., & Yang, G. F. (2007). J. Agric. Food. Chem., 55, 5697.
[12] Imrie, C. T. (1999). Struct. Bond.,95, 149.
[13] Gray G. W., & Winsor, P. A. (1974). In: Liquid crystals and plastic crystals, Chapter 4. Volume 1,
Ellis Horwood: Chichester, 103.
[14] Gray, G. W. (1962). Molecular structures and properties of liquid crystals, Academic Press: London.
[15] Henderson, P. A., Niemeyer, O., & Imrie, C. T. (2001). Liq. Cryst., 28, 463.
[16] Stewart, G. T. (2003). Liq. Cryst., 30, 541.
[17] Hird, M., Toyne, K. J., Gray, G. W., Day, S. E, & Mc Donnell, D.G. (1993). Liq. Cryst., 15, 123.
[18] Collings, P. J., & Hird, M. (1998). Introduction of liquid crystals chemistry and physics, Taylor and
Francis Ltd.: U. K.
[19] Marcos, M., Omenat, A., Serrano, J. L., & Ezcurra, A. (1992). Adv. Matter, 4, 285.
[20] Hird, M, Toyne, K. J., Gray, G. W., Day, S. E. (1993). Liq. Cryst., 14, 741.
[21] Demus, D. (1988). Mol. Cryst. Liq. Cryst., 165, 45.
[22] Demus, D. (1988). Liq. Cryst, 5, 75.

MOLECULAR CRYSTALS AND LIQUID CRYSTALS
187
[23] (i) Chauhan, H. N., & Doshi, A. V. (2013). Mol. Cryst. Liq. Cryst., 570, 92. (ii) Chaudhary, R. P.,
Chauhan, M. L., & Doshi, A. V. (2013). Mol. Cryst. Liq. Cryst., 575, 88. (iii)Bhoya, U. C., Vyas, N.
N., & Doshi, A. V. (2012). Mol. Cryst. Liq. Cryst., 552. 104.
[24] Makwana, N. G, & Doshi, A. V. (2011). Der Pharma Chemica., 3(2), 433.
[25] (a) Patel, B. H., & Doshi, A. V. (2015). Mol. Cryst. Liq. Cryst., 607, 38. (b) Tandel, R. C., Gohil, J.,
& Patel, N. K. (2012). Res. J. Recent. Sci., 1, 122.
[26] (a) Marathe, R. B., & Doshi, A. V. (2016). Mol. Cryst. Liq. Cryst., 624, 122. (b) Marathe, R. B., &
Doshi, A. V. (2016). Mol. Cryst. Liq. Cryst., 625, 81.
[27] Suthar, D. M., Doshi, A. A., Doshi, A. V. (2013). Mol. Cryst. Liq. Cryst., 582, 79.
[28] Hasan, A., Abbas, A., & Akhtar, M. N. (2011). Molecule, 16, 7789.
[29] Nikitin, K. V., Andryukhova, N. P. (2004). Can. J. Chem., 82, 571.
[30] Furniss, B. S., Hannford, A. J., Smith, P. W. G., & Tatchell, A. R. (1989). Vogel’s Textbook of Practical
Organic Chemistry (4th edn.), Longmann Singapore Publishers Pvt. Ltd.: Singapore, 563.
[31] Pandya, S. H., & Patel, V. R. (2016). Mol. Cryst. Liq. Cryst., 638, 806.