Mesomorphism dependence on lateral substitution and central bridge

Article abstract of DOI:10.1080/15421406.2015.1044637

A novel ester homologous series was synthesized and studied with a view to understanding and establishing the effects of molecular structure on liquid crystal properties with a common laterally substituted-OCH3 group and changing terminal groups. The novel series consists of twelve members. The C₁ to C₃ members are not liquid crystals and the rest of the members C₄ to C₁₆ are smectogenic without exhibition of nematic character. Textures of smectic phase are focal conic fan shaped of the type A or C. The transition temperatures and textures of smectic mesophases were observed through hot stage polarizing microscopy (POM). The transition curves (Cr-I or Cr-M and Sm-I) behaved in normal manner. Analytical and spectral data support the molecular structures. Average thermal stability for smectic is 77.25°C and smectogenic mesophase ranges from 15°C to 33°C. Liquid crystal properties of the present series are compared with structurally similar homologous series. Thus, the series is smectogenic only with three homologs nonmesogenic.

Full text of DOI:10.1080/15421406.2015.1044637

Molecular Crystals and Liquid Crystals
ISSN: 1542-1406 (Print) 1563-5287 (Online) Journal homepage: http://www.tandfonline.com/loi/gmcl20
Mesomorphism dependence on lateral
substitution and central bridge
M. S. Vadodaria, K. D. Ladva, A. V. Doshi & J. J. Travadi
To cite this article: M. S. Vadodaria, K. D. Ladva, A. V. Doshi & J. J. Travadi (2016)
Mesomorphism dependence on lateral substitution and central bridge, Molecular Crystals and
Liquid Crystals, 624:1, 103-111, DOI: 10.1080/15421406.2015.1044637
To link to this article: http://dx.doi.org/10.1080/15421406.2015.1044637
Published online: 11 Feb 2016.
Submit your article to this journal
Article views: 10
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: [University of Toronto Libraries]
Date: 01 April 2016, At: 13:09

MOL. CRYST. LIQ. CRYST.
, VOL. , NO. , –
http://dx.doi.org/./..
Mesomorphism dependence on lateral substitution and central
bridge
M. S. Vadodariaa, K. D. Ladvaa, A. V. Doshib, and J. J. Travadic
aChemistry Department, Shree M. & N. Virani Sc. College, Rajkot, Gujarat, India; bEx. Principal, Matushri Virbaima
Mahila Science and Home Science College, Rajkot, Gujarat, India; cChemistry Department, Kamani Sc. College
and Prataprai Arts College, Amreli, Gujarat, India
ABSTRACT
KEYWORDS
Liquid crystal; mesogenic;
monotropy; nematic; smectic
A novel ester homologous series was synthesized and studied with a
view to understanding and establishing the effects of molecular struc-
ture on liquid crystal properties with a common laterally substituted –
OCH3 group and changing terminal groups. The novel series consists
of twelve members. The C1 to C3 members are not liquid crystals and
the rest of the members C4 to C16 are smectogenic without exhibition of
nematic character. Textures of smectic phase are focal conic fan shaped
of the type A or C. The transition temperatures and textures of smectic
mesophases were observed through hot stage polarizing microscopy
(POM). The transition curves (Cr-I or Cr-M and Sm-I) behaved in nor-
mal manner. Analytical and spectral data support the molecular struc-
tures. Average thermal stability for smectic is 77.25°C and smectogenic
mesophase ranges from 15°C to 33°C. Liquid crystal properties of the
present series arecomparedwith structurallysimilar homologous series.
Thus, the series is smectogenic only with three homologs nonmeso-
genic.
Introduction
Study of mesomorphism and the degree of mesomorphism are important from an applica-
tion’s point [1–4] of view in both thermotropic and lyotropic liquid crystals since their discov-
ery in 1888 [5]. The present investigation is planned to synthesize novel ester [6–9] derivatives
of thermotropic liquid crystals with a view to understanding the effects of molecular struc-
–
ture [10,11] on liquid crystal properties by selecting a OCH3 lateral group bonded at the
–
ortho position of the central bridge linking two phenyl rings and a para-substituted OR and
–
=
–
–
CH CH COO C6H13 (n) end groups. The steric hindrance and polarizability lowers tran-
sition temperatures, which may be useful to the researchers working specially in the applica-
tions of LC materials in LC devices workable at low temperatures or room temperature. The
LC behaviors of the proposed novel substances will be explained on the basis of molecular
rigidity and flexibility [12–16].
CONTACT J. J. Travadi and M. S. Vadodaria,
j.travadi@gmail.com, milanvadodaria@yahoo.com
Radhika Hospital, Chittal Road, Amreli, Gujarat, , or Chemistry Department, Shree M. & N. Virani Sc. College, “Yogidham”,
Kalavad Road, Rajkot, Gujarat, India.
Jyotirav nagar, opp.
©  Taylor & Francis Group, LLC

104
M. S. VADODARIA ET AL.
Experimental
Synthesis
4-Hydroxy 3-methoxy cinnamic acid (m.p. 64°C, yield 67%) was esterified by n-hexenol by
using conc. H2SO4 by a usual established method [17]. The ester was very viscous and dense
brown liquid, which was purified from distilled n-hexane. The yield was 65.3%. 4-Hydroxy
benzoic acid was alkylated by suitable alkylating agents (R-X) to convert it into dimeric 4-
n-alkoxy benzoic acids by the modified method of Dave and Vora [18]. Dimeric 4-n-alkoxy
benzoic acids were individually condensed with 4-hydroxy, 3-methoxy n-hexyl cinnamate in
dry cold pyridine through the corresponding acid chlorides [19]. Final products were individ-
ually decomposed, filtered, washed, dried, and purified until constant transition temperatures
obtained.
The synthetic route to the series is shown below in Scheme 1.
Scheme . Synthetic route to the series.
The chemicals required such as 4-hydroxy benzoic acid, MeOH, KOH, alkyl halides (R-
X), thionyl chloride, 4-hydroxy,3-methoxy, cinnamic acid (Ferulic acid), n-Hexenol, Conc.
H2SO4, Pyridine, 1:1 HCl, NaHCO3, NaOH, anhydrous CaCl2, silica gel, Petroleum ether,
methyl acetate, and n-hexane were used as received, except solvents which were dried and
purified prior to use.
Characterization
Representative homologs of the series were selected for characterization of structure by ele-
mental analysis, IR spectra, and 1H NMR spectroscopy.
Microanalysis was performed on a Perkin Elmer PE 2400 CHN analyzer. IR spectra were
recorded on Perkin Elmer spectra GX. 1H NMR spectroscopy performed were recorded on
Bruker spectrometer using CDCl3 as solvent. The mesomorphic properties were investigated
using a hot stage polarizing microscope.

MOL. CRYST. LIQ. CRYST.
105
Analytical data
Elemental analysis for ethyloxy, pentyloxy, decyloxy, and tetradecyloxy derivatives
IR spectra in cm-1 for hexyloxy and dodecyloxy homolog derivatives
Hexyloxy
–
The IR spectrum of the compound showed 765.47 cm-1 polymethylene of C6H13 group.
–
–
848.26 cm-1 as p-sub. benzene ring, 1131.55 cm-1 as CO of alkoxy group, 1244.24, 1508.86,
–
–
1634.08, and 1706.13 cm-1 Confirms COO of ester group, 928.89 and 995.57 cm-1 Con-
firms trans CH CH group, 2878.06 and 3097.77 cm-1 Confirms alkyl group.
–
=
–
IR supports the structure
Dodecyloxy
–
The IR spectrum of the compound showed 686.16 cm-1polymethylene of C6H13 group.
–
–
748.11 and 832.78 cm-1 as p-sub. benzene ring, 1132.73 and 1217.74 cm-1 as CO of alkoxy
–
–
group, 1298.61, 1576.69, and 1672.75 cm-1 Confirms COO of ester group, 941.51 and
1094.44 cm-1 Confirms trans CH CH group, 3172.74 and 3229.18 cm-1 Confirms alkyl
–
=
–
group.
IR supports the structure
1H NMR spectra in ppm for hexyloxy and decyloxy derivatives
Hexyloxy
H1 NMR data in δ ppm (n-hexyloxy derivative, 400 MHz, CDCl3, standard TMS):
–
–
–
–
–
0.807 ( CH3 of C6H13), 1.2516 & 1.1745 ( CH2 of – C6H13), 1.7393 ( OCH2 CH2
– –
– –
–
of – C6H13), 3.7641 ( O CH3), 3.9579 ( O CH2- of C6H13), 7.0841 & 7.0684
– –
–
=
–
–
( O C6H4 CH CH CO ), 8.0559 & 8.0781 (p-sub. Benzene ring).
The data supports the molecular structure
Decyloxy
H1 NMR data in δ ppm (n-decyloxy derivative, 400 MHz CDCl3, standard TMS): 0.8101
–
–
–
–
–
–
–
( CH3 of C10H21), 1.2356 ( CH2 of C10H21), 1.759 ( OCH2 CH2 of C10H21), 3.8083
– –
– –
– –
–
=
–
–
( O CH3), 3.9598 ( O CH2- of – C10H21), 7.0034 and 7.0074 ( O C6H4 CH CH CO ),
8.058 and 8.08 (p-sub. Benzene ring).
The data supports the molecular structure
Textures of mesophase by miscibility method
r
Octyloxy homolog——→ Smectic - A
r
Hexyloxy homolog——→ Smectic - A
r
Hexadecyloxy homolog ——→ Smectic - C
Mass spectra
Homolog:
Theoretical
Experimental
C
C
.
.

.

106
M. S. VADODARIA ET AL.
Table . Elemental analysis for ethyloxy, pentyloxy, decyloxy and tetradecyloxy derivatives.
Compound
no.
Molecular
formula
Mol.% of C Experimental
(Theoretical)
Mol.% of H Experimental
(Theoretical)
C
C
C
C
CHO
CHO
CHO
CHO
. (.)
. (.)
. (.)
. (.)
. (.)
. (.)
. (.)
. (.)
Results and discussion
4-Hydroxy-3-methoxy –n-hexyl cinnamate (very viscous and dense brown liquid, yield
65.3%) is a nonliquid crystal component. However, mesomorphism is induced by linking it
with 4-n-alkoxy benzoic acids, from C4 member of a series to last hexadecyloxy (C16) member.
Transition temperatures of esters formed have relatively lower than the corresponding dimer-
ized n-alkoxy aromatic acids. C1 to C3 members are nonmesomorphic, C4 is monotropic
smectic, C5 to C16 members are enantitropically smectic. Transition temperatures (Table 2)
as determined by an optical polarizing microscope are plotted versus the number of car-
bon atoms present in n-alkyl chain of left n-alkoxy terminal end group. Transition curves
are obtained on linking like or related points showing phase behaviors of a series. Solid-
mesomorphic or isotropic transition curve partly adopt a zigzag path of rising and falling
tendency as series is ascended with overall descending tendency. Smectic-Isotropic (or vice
versa) transition curve gradually rises, passes through maxima at the decyloxy (C10) homolog
and then descended as series is ascended. Thus, Cr-M or Cr-I and Sm-I transition curve
behaved in normal manner in a phase diagram (Fig. 1). Sm-I transition curve exhibited odd-
even effect. Curves (Sm-I) for odd and even members are merging into each other at octyloxy
(C8) derivative of a series and then the Sm-I transition curve prolonged from and beyond C8
homolog as a single transition curve. Analytical and spectral data supported molecular struc-
ture. Nematic mesophase formation is totally absent. The mesogenic properties vary from
homolog to homolog in present series. Thus, present series is smectogenic with an average
thermal stability is 77.25°C and mesogenic phase-length vary between 15°C and 33°C. The
isotropic temperatures of liquid crystalline homologs are between 64°C and 107°C, hence it
is a low-melting type of series.
Linking of dimerized n-alkoxy benzoic acids with 4-hydroxy-3-methoxy-n-hexyl cinna-
mate increases length to breadth ratio, polarity, and polarizability of molecules, end-to-end
Table . Transition temperatures in °C.
n-Alkyl group R =
–
Compound No.
CnHn+
Sm
N
Isotropic












C
C
C
C
C
C
C
C
C
C
C
C
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
.
.
.
.
.
.
.
(.)
.
.
.
.
.
.
.
.
.
.
.
.
.
() indicates monotropy.

MOL. CRYST. LIQ. CRYST.
107
Figure . Phase behaviors of series.
and lateral attractions, permanent dipole moment across the long molecular axis, etc., as
a result of yielded molecular rigidity and flexibility. Therefore, magnitudes of anisotropic
forces of intermolecular attractions attain suitability to induced mesophase (Sm) from buty-
loxy homolog (C4) to hexadecyloxy (C16) homolog. The lowering of transition tempera-
tures in comparison with corresponding n-alkoxy acids and disappearance of their dimer-
ization is attributed to the breaking of hydrogen bonding between two molecules of aro-
matic acids by esterification process. Thus, smectogenic mesophase commences from buty-
loxy homolog derivative. Nonliquid crystalline behaviors of methoxy, ethoxy, and propyloxy
(C1–C3) homologs is attributed to their high crystallizing tendency arising from unsuitable
magnitudes of molecular rigidity and flexibility induced by low dipole-dipole interactions and
low magnitudes of dispersion forces by the interactions between instantaneous dipoles pro-
duced by the spontaneous oscillations of electron clouds of the molecules. Thus, the C1 to
C3 homologs are unable to resist exposed thermal vibrations. Hence, the crystal lattices of
molecules are abruptly breaking and sharply transformed into the isotropic liquid without
passing through an intermediate liquid crystalline state. Thus, exhibition of high crystalliz-
ing tendency precludes showing up of nematic property even in a monotropic condition. The
exhibition of the smectic mesophase from and beyond the C4 homolog is attributed to the
layered arrangement of molecules through their lamellar packing. On cooling of the isotropic
melt of the C4 homolog a monotropically induced smectic phase arises, and the rest of the
homologs (C5 to C16) exhibit an enantiotropic smectic phase. The textures of the smectic
phase are focal conic fan shaped of the type smectic A or C. The terminal attractions are not
sufficiently strong enough to induce a nematic phase because of the overall molecular polariz-
ability, including polarizability due to laterally substituted –OCH3 group. The odd-even effect
observed for the smectic-isotropic (or vice versa) transition curve is due to alternation of tran-
sition temperatures for C4, C5, C6, and C7 homologs. The disappearance of the odd-even effect
from and beyond the octyloxy (C8) homolog is attributed to the longer n-alkyl chains, which
may coil, bend or flex or couple to lie with major axis of the core structure of the molecules.
The variations in mesomorphic properties for homolog to homolog in the same series is due
to the sequential and progressive addition of a methylene unit in the terminal chain. The low
thermal stability (77.25°C) and mesophase lengths (15°C–33°C) is attributed to the low resis-
tivity of the molecules toward exposed thermal vibrations. The liquid crystal properties of

108
M. S. VADODARIA ET AL.
presently investigated novel homologous series-1 are compared with the structurally similar
known homologous series-X [20] and -Y [21] as mentioned below in Fig. 2.
Homologous series-1 of present investigation and the homologous series-X and -Y cho-
sen for comparison are identical with respect to two phenyl rings, right-side terminal end
–
=
–
group CH CH COOC6H13(n) and left terminal end group –OR for the same homolog
from series to series. However, a homologous series-1 differs from series-X and -Y with respect
to laterally substituted –OCH3 polar group which induces polarizability factor and steric hin-
drance in addition to length-to-breadth ratio and the ratio of the molecular polarizability etc.,
which differs considerably. Homologous series-1 and -X are identical with respect to central
–
–
–
–
bridge COO , but it differs from series-Y in which central bridge COO is replaced by
–
=
–
–
CH CH COO . Thus, liquid crystal properties and the degree of mesomorphism depend
upon the differing features of series-1, -X, and -Y as a consequence of changing magnitudes of
molecular rigidity and flexibility. Table 3 represents some properties related to liquid crystal
state as under.
Table 3 indicates that,
r
Homologous series-1 is only smectgenic, whereas series-X and -Y are nematogenic in
addition to smectogenic mesophase formation.
r
Smectogenic character commences earlier from C4 homolog in a present series-1,
whereas it commences late from C8 and C7 homologs in series-X and -Y, respectively.
r
Nematic mesophase commences from C6 and C3 homolog in series-X and -Y, respec-
tively, whereas it does not commence till the last homolog (C16) of a present series-1.
r
Mesomorphic phaselength range of present series is the shortest (10°C–33°C), whereas
it is the highest (10°C–60°C) for series-Y and 24°C–60°C for series-X.
r
Smectic thermal stability gradually increases from series-1 to series-X to series-Y.
r
Nematic thermal stability is zero for series-1 and it increases from series-X (136.4°C) to
Y (190.9°C).
r
Odd-even effects are exhibited by transition curves in a phase diagrams of series-1 and
-Y, whereas it is absent for the curves of series-X.
Homologous series-1 of present investigation bears laterally substituted –OCH3 group at
–
–
the ortho position to central COO group, whereas series-X and -Y are linear lath like.
Therefore, intermolecular distance between any two molecules of series-1 is wider than the
series-X and -Y under identical condition. Enhancement in intermolecular distance can cause
Figure . Structurally similar series.

MOL. CRYST. LIQ. CRYST.
109
Table . Relative thermal stability in °C.
Series:→

. (C–C)
C
X
. (C–C)
C
Y
. (C–C)
C
Smectic-isotropic or
Smectic-nematic
Commencement of
Smectic phase
Nematic-isotropic
Commencement of
nematic phase
Mesophaselength (Sm
+N) in °C
–
–
. (C–C)
C
. (C–C)
C
–
–
–
reduction in anisotropic forces of intermolecular end-to-end and lateral attractions on one
hand and at the same time, the intermolecular attractions are raised by increasing molecular
polarizability through laterally substituted –OCH3 polar group in case of molecules of series-
1 as compared to the corresponding molecules of series-X and -Y. Thus, two opposing forces
are operated at a time for the same reason. Therefore, the resultant or effective intermolecular
attractions depend upon the predominancy or effectiveness of two opposing effects operated
at a time. The molecules of series-X and -Y being linear and lath like without any laterally sub-
stituted group, obviously undergo stronger intermolecular anisotropic forces of end-to-end
and lateral attractions than corresponding homolog of series-1. Thus, from the values of ther-
mal stabilities as indicated in Table 3 suggests that the increase in the intermolecular distance
by the presence of lateral –OCH3 group in case of series-1 predominates and surpasses the
effect due to polarizability factor for the same homolog from series to series. Thus, the thermal
stability and mesophase length range of series-1 are lower than the series-X and -Y. The high-
est value of thermal stability and mesophase length of series-Y is attributed to the presence of
–
=
–
–
CH CH COO as central and terminal group which increases molecular length and con-
–
–
jugated double bond as compared to series-1 and -X as these series contain shorter COO
–
=
–
–
central group in place of CH CH COO central group. Hence, the length to breadth ratio
is favorable more for the molecules of series-Y than the series-1 and -X. Thus, suitable mag-
nitudes of anisotropic forces of intermolecular attractions resist or withstand against exposed
thermal vibrations for longer degree of mesomorphism to stabilize and facilitate smectic and
nematic mesophases one after another in case of series-X and -Y. The steric hindrance caused
by –OCH3 lateral group which hinders the stabilization of nematic mesophase formation and
permits only the stabilization of focal conic fan-shaped mesophase formation of smectic A or
C type due to originally present lamellar packing of molecules in crystal lattices of homologs
of series-1. Unexhibition of odd-even effect by the mesomorphic homologs of series-X is
attributed to the late commencement (from C6) of mesophase (only even members) from
which alternation of transition temperatures diminish, that is, early odd members C1, C3, and
C5 are nonmesomorphic, whereas in case of series-Y and -1 the mesophase commences from
C3 and C4 members of respective series, which created the possibility of the effect under dis-
cussion. The suitable magnitudes of anisotropic forces of intermolecular end-to-end or/and
lateral attractions which is a driving force to induce early or late mesophase, as a consequence
of favorable molecular rigidity and/or flexibility which depend upon molecular structure only,
and it varies from series to series. Thus, changing trend and type of mesophase for the same
homolog from series to series in present comparison depend upon changing either central
group or due to the presence or absence of lateral group keeping rest of the molecular part
unchanged.

110
M. S. VADODARIA ET AL.
Conclusions
Present novel ester homologous series of twelve homologs gives rise to nine smectogenic
mesomorphs by lateral substitution of –OCH3 group which broadens the molecules and
affects molecular polarizability and causes steric hindrance.
r
Present novel series is smectogenic without exhibition of nematic property.
r
Group efficiency order derived on the basis of (i) thermal stability, (ii) early commence-
ment of mesophase, and (iii) mesophase length range for smectic and/or nematic are as
under.
i. Nematic
–
–
–
–
H with> H> OCH3
=
–
–
–
–
–
–
CH CH COO central group with COO central group with COO central
group
Smectic
–
–
–
–
H> H> OCH3
=
–
–
–
–
–
–
with CH CH COO with COO with COO
ii. Smectic
–
–
–
OCH3> H> H
–
–
–
=
–
–
–
–
with COO With CH CH COO with COO
Nematic
–
–
–
–
H> H> OCH3
=
–
–
–
–
–
–
with CH CH COO with COO with COO
iii. Smectic
–
–
–
H> H> OCH3
–
=
–
–
–
–
–
–
with CH CH COO with COO with COO
r
r
r
Mesomorphic properties (LC) and the degree of mesomorphism are sensitive and sus-
ceptible to molecular structure.
Suitable magnitudes of molecular rigidity and flexibility are the driving forces to induce
mesomorphism.
Present investigation may be useful for the following:
(i) The devices to be operated at desired temperature or room temperature by the study of
mixed mesomorphism or using directly a homolog between 40°C and 60°C.
(ii) Biological activity study for the growth of flower and fruits.
(iii) The researchers working on applications of LC.
Acknowledgments
The authors are especially thankful to management, principal, and HOD (Chemistry Dept.) of Shree
M. and N. Virani Sc. College, Rajkot and Kamani Sc. College and Prataprai Arts College, Amreli for
their valuable cooperation to facilitate for present research work and IR spectra. The authors are also
thankful to the authorities of Saurashtra University for analytical services.
References
[1] Kim, W. S., Elston, S. J., & Raynes, F. P. (2008). Displays, 29, 458–463.
[2] Naemura, S. (2001). Displays, 12(1
[3] Iwabuta, K., et al. (2013). Molecules, 18, 4703–4717.
[4] (a) Tadwee, I., Shahi, S., Ramteke V., & Syed, I. (2012). “IJPRAS” Int. J. Pharm. Res. Allied Sci., 1(2),
06–11. (b) Darshan Raj, B. K. et al. (2013). Der Pharma Chemica, 5(3), 305–317.

MOL. CRYST. LIQ. CRYST.
111
[5] Reinitzer, F. (1888). Monatsch, 9, 421.
[6] Demus, D. (1988). Mol. Cryst. Liq. Cryst., 165, 45–84.
[7] Demus, D. (1989). Liq. Cryst., 5, 75–110.
[8] Gray, G. W. (1958). In: Steric Effects in Conjugated System, Gray, G. W. (Ed.), Bulterworths: Lon-
don.
[9] Lohar, J. M., & Doshi, A. V. (1993). Proc. Ind. Acad. Sci. (Chem. Sci.)., 105, 209–214.
[10] Gray, G. W. (1962). Molecular Structure and the Properties of Liquid Crystals, Academic Press:
London.
[11] Gray, G. W., & Windsor, P. A. (1974). Liquid Crystals and Plastic Crystals, Vol. 1., Chapter 4, Ellis
Horwood Ltd.: Chichester Halsted Press, U.K.
[12] Collings, P. J., & Hird, M. (1997). Introduction to Liquid Crystals Chemistry and Physics, Taylor
and Francis: New York.
[13] Hird, M., Toyne, K. J., & Gray, G. W. (1993). Liq. Cryst., 14, 741.
[14] Marcos, M., Omenat, A., Serrano, J. L., & Ezcurra, A. (1992). Adv. Mater., 4, 285.
[15] (a) Hird, M., Toyne, K. J., Gray, G. W., Day, S. E., & Mc Donnell, D. G. (1993). Liq. Cryst., 15, 123.
(b) Gonzalez, Y., Ros, M. B., Serrano, J. L., & Perezjubind, A. (1998). Liq. Cryt., 18, 751.
[16] (a) Imrie, C. T. (1999). Liq. Crystal Dimmers. Struct. Bond, 95, 149–192. (b) Imrie, C. T. & Luck-
hurst, G. R. (1998). Liquid crystal dimers, oligomers. In: Handbook of Liquid Crystals, Vol. 2B: Low
Molecular Weight Liquid Crystals, pp. 801-833, Demus, D., Goodby, J. W., Gray, G. W., Spiess H.
W., Vill, V., Eds., Wiley-VCH: Weinheim, Germany. (c) Imrie, C. T., & Henderson, P. A. (2007).
Chem. Soc. Rev., 36, 2096–2124.
[17] Vogel, A. I. (1989). Text Book of Practical Organic Chemistry, 5th ed. ELBS: Longman, London, p.
946.
[18] Dave, J. S., & Vora, R. A., (1970). Liquid Crystal and Ordered Fluids, Plenum Press: New York.
[19] (a) Bhoya, U. C., Vyas, N. N., & Doshi, A. V. (2012). Mol. Cryst. Liq. Cryst., 624, 104–110. (b)
Doshi, A. V., & Ganatra, K. J. (2000). J. Ind. Chem. Soc., 77, 61–64. (c) Doshi, A. V., Bhoya, U. C.,
& Travadi, J. J. (2012). Mol. Cryst. Liq. Cryst., 552, 10–15.
[20] Chauhan, M. L. (Nov. 2006). Ph.D. Thesis entitled “Synthesis and study of mesogenic material”
submitted to the Saurastra University. Rajkot, Gujarat.
[21] Doshi, A. V., & Patel, R. B. (2011). Der Pharma Chemica, 3(1), 338–348.