Mesomorphism Dependence on Molecular Flexibility by -OCH3 and -H Terminal Units

Article abstract of DOI:10.1080/15421406.2014.953743

A novel ester homologous series: 4-(4′-n-Alkoxy benzoyloxy)-4″-methoxy benzyl cinnamates have been synthesized and studied with a view to understanding and establishing the dependence of liquid crystal behavior on molecular structure. The novel series of eleven homologues is entirely nematogenic without exhibition of any smectogenic character from the very first member of the series. Transition and melting temperatures were determined by an optical polarizing microscopy equipped with a heating stage. Transition curves of a phase diagram show the mesomorphism, which behaves in normal manner. An odd-even effect is exhibited by the nematic-isotropic transition curve. The textures of the nematic mesophase are threaded or schlieren in type. Analytical and spectral data confirm the molecular structures of the novel homologues. Thermal stability for the nematic phase is 211.5°C and the degree of mesomorphism varies from 17°C to 72°C and it is a high melting type series. Mesomorphic properties of the series are compared with structurally similar series.

Full text of DOI:10.1080/15421406.2014.953743

This article was downloaded by: [FU Berlin]
On: 07 May 2015, At: 20:06
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered
office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
Molecular Crystals and Liquid Crystals
Publication details, including instructions for authors and
subscription information:
http://www.tandfonline.com/loi/gmcl20
Mesomorphism Dependence on Molecular
Flexibility by –OCH3 and –H Terminal
Units
B. H. Patela, V. R. Patelb & A. V. Doshic
a Huntsman International India Private Limited, Vadodara, Gujarat,
India
b Sheth P.T. Arts & Science College, Godhra, Gujarat, India
c Dr K. N. Modi University, Newai, Rajasthan, India
Published online: 11 Apr 2015.
Click for updates
To cite this article: B. H. Patel, V. R. Patel & A. V. Doshi (2015) Mesomorphism Dependence on
Molecular Flexibility by –OCH3 and –H Terminal Units, Molecular Crystals and Liquid Crystals, 609:1,
10-18, DOI: 10.1080/15421406.2014.953743
To link to this article: http://dx.doi.org/10.1080/15421406.2014.953743
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the information (the
“Content”) contained in the publications on our platform. However, Taylor & Francis,
our agents, and our licensors make no representations or warranties whatsoever as to
the accuracy, completeness, or suitability for any purpose of the Content. Any opinions
and views expressed in this publication are the opinions and views of the authors,
and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content
should not be relied upon and should be independently verified with primary sources
of information. Taylor and Francis shall not be liable for any losses, actions, claims,
proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or
howsoever caused arising directly or indirectly in connection with, in relation to or arising
out of the use of the Content.
This article may be used for research, teaching, and private study purposes. Any
substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing,
systematic supply, or distribution in any form to anyone is expressly forbidden. Terms &

Conditions of access and use can be found at http://www.tandfonline.com/page/terms-
and-conditions

Mol. Cryst. Liq. Cryst., Vol. 609: pp. 10–18, 2015
Copyright © Taylor & Francis Group, LLC
ISSN: 1542-1406 print/1563-5287 online
DOI: 10.1080/15421406.2014.953743
Mesomorphism Dependence on Molecular
Flexibility by –OCH3 and –H Terminal Units
B. H. PATEL,1,∗ V. R. PATEL,2 AND A. V. DOSHI3
1Huntsman International India Private Limited, Vadodara, Gujarat, India
2Sheth P.T. Arts & Science College, Godhra, Gujarat, India
3Dr K. N. Modi University, Newai, Rajasthan, India
A novel ester homologous series: 4-(4’-n-Alkoxy benzoyloxy)-4”-methoxy benzyl cinna-
mates have been synthesized and studied with a view to understanding and establishing
the dependence of liquid crystal behavior on molecular structure. The novel series
of eleven homologues is entirely nematogenic without exhibition of any smectogenic
character from the very first member of the series. Transition and melting temperatures
were determined by an optical polarizing microscopy equipped with a heating stage.
Transition curves of a phase diagram show the mesomorphism, which behaves in nor-
mal manner. An odd-even effect is exhibited by the nematic–isotropic transition curve.
The textures of the nematic mesophase are threaded or schlieren in type. Analytical
and spectral data confirm the molecular structures of the novel homologues. Thermal
stability for the nematic phase is 211.5◦C and the degree of mesomorphism varies from
17◦C to 72◦C and it is a high melting type series. Mesomorphic properties of the series
are compared with structurally similar series.
Keywords Liquid crystals; mesomorphism; mesomorphs; nematic; smectic
Introduction
The study of liquid crystalline state [1, 2] is very important because of applications in
the fields of electronic display devices, medical instruments, agriculture, pharmaceuticals
preparations, dyes, plastics, and textiles [3–6] arising from a dual role of flow as a liquid and
of molecular ordering that orients under the influence of electric and/or magnetic field [7, 8].
Therefore, such a unique state of matter between crystalline state and isotropic liquid state is
studied with keen interest by the chemists, physicists, biologists, pharmacists, agriculturists,
and technologists with different aims. A chemist has to study and synthesize novel liquid
crystalline (LC) materials, to characterize their structures and textures, its mesomorphic
phase length and to establish the relation between molecular structure and LC properties of
a material of either thermotropic or lyotropic type [9–11]. Other researchers exploit the LC
state of novel substances with different aims and objectives [12, 13]. The present study is
aimed to synthesize novel thermotropic LC substances derived from derivatives of benzyl
alcohol to study their LC properties by polarizing microscopy, to characterize their structure
and textures and finally to correlate and to establish the relation between LC behavior and
the molecular structure on the basis of molecular rigidity and flexibility [14–17].
∗Address correspondence to Brijesh H. Patel, Huntsman International India Private Limited,
Vadodara, Gujarat, India; E-mail: brijpatel79@gmail.com
10

Mesomorphism Dependence on Molecular Flexibility
11
Experimental
Synthesis
4-Hydroxy benzoic acid was converted to 4-n-alkoxy benzoic acids using suitable alkylating
(R-X) agents by modified method of Dave and Vora [18]. 4-Hydroxy cinnamic acid was
converted to 4-hydroxy-4’-methoxy benzyl cinnamate by the modified method of European
patent EP0117502B1 [19]. 4-n-alkoxy cinnamic acids were individually condensed with
4-hydroxy-4’-methoxy benzyl cinnamate (m.p. 204◦C, yield is 35%) in pyridine through
their acid chlorides in dry cold pyridine [20]. Final products were individually decomposed,
filtered, washed dried, and purified in ethanol until constant transition temperatures were
obtained. Transition and melting temperatures were determined by an optical hot stage
polarizing microscopy.
The chemicals 4-hydroxy cinnamic acid, 4-methoxy benzyl alcohol, dibutyltin oxide,
pyridine, alkyl halides, MeOH, EtOH, thionyl chloride, HCl, and KOH were used as
received, except solvents, which were dried and distilled prior to use. The synthetic route
to the series is shown in Scheme 1.
Scheme 1. Synthetic route to the series. Where R = CnH2n+1; n = 1,2,3,4,5,6,8,10,12,14,16.

12
B. H. Patel et al.
Characterization
Some selected members of the present novel series were characterized by elemental anal-
1
ysis, infra red spectra, HNMR spectra, and mass spectra. Micro analysis was performed
using a Perkin-Elmer PE 2400 CHN analyzer, 1HNMR spectra were recorded on a Bruker
instrument using dimethyl sulfoxide solvent. Infrared spectra were recorded on Perkin
Elmer spectrum GX spectrometer. Transition temperatures and the textures of the nematic
mesophases were determined by a miscibility method through an optical polarizing micro-
scope equipped with a heating stage.
Analytical Data
Table 1. Elemental analysis for methyloxy, ethyloxy, and propyloxy derivatives
Elements % found (% calculated)
Sr. no.
Molecular formula
C
H
1
2
3
C25H22O6
C26H24O6
C27H26O6
71.55 (71.77)
72.17 (72.22)
74.60 (72.64)
5.18 (5.26)
5.28 (5.55)
5.71 (5.82)
Spectral Data
1HNMR in ppm for the decyloxy Derivative: 0.85–1.76 (H of C10H21), 2.51
( O CH2 CH2 of OC10H21), 3.73 ( OCH3), 3.98 ( O CH2 of O C10H21), 5.04
( CH CH ), 6.51 (p-substituted benzene ring) 6.9–8.09 (indicates presence of more than
one benzene rings).
1HNMR in ppm for the dodecyloxy Derivative: 0.80–1.67 (H of C12H25), 2.50
( OCH2 CH2 of OC12H25), 3.7 ( OCH3), 3.95 ( O CH2 of O C12H25), 5.06
( CH CH ), 6.51 (p-substituted benzene ring), 6.9–7.7 (presence of more than one
benzene rings).
IR in cm−1 for tetradecyloxy Derivative: 831 parasubstituted phenyl ring, 1216 ether
linkage of ( C14H29 O C6H4), 1171, 1238,1686 ( COO ester group), 981 (trans
CH CH ).
IR in cm−1 for hexadecyloxy Derivative: 830 para-substituted phenyl ring, 1217 ether
linkage of ( C16H33 O C6H4), 1171, 1238, 1685 ( COO ester group), 981 (trans
CH CH ).
Mass Spectra
Mass spectra for butyloxy Derivative: Molecular formula C28H30O6 Calculated Molecular
weight 460. Practical mass observed by Mass spectroscopy 460.
Texture of Nematic by Miscibility Method
Pentyloxy derivative —————–→Threaded nematic

Mesomorphism Dependence on Molecular Flexibility
13
Table 2. Transition temperatures of series in ◦C
Transition temperature in ◦C
Compound no.
n-alkyl group ( CnH2n+1) (n)
Sm
N
Isotropic
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
8
10
12
14
16
—
—
—
—
—
—
—
—
—
—
—
193.0
127.0
163.0
183.0
188.0
172.0
181.0
166.0
174.0
183.0
170.0
226.0
190.0
235.0
212.0
214.0
213.0
213.0
230.0
198.0
200.0
196.0
10
11
Sm: Smectic N: Nematic.
Hexyloxy derivative —————–→Threaded nematic
Octyloxy derivative —————–→Schlieren nematic
Results and Discussion
All the eleven members of the novel series are enantiotropcially nematogenic without the
exhibition of any smectogenic character. Transition temperatures, melting temperatures,
and texture of mesophase were determined by an optical polarizing microscopy, equipped
with a heating stage. Transition and melting temperatures (Table 2) of homologues were
plotted versus the number of carbon atoms present in n-alkoxy terminal end group. Like or
related points were linked to form solid-nematic and nematic–isotropic transition curves to
construct a phase diagram (Fig. 1) showing phase behaviors of a novel series. The solid-
nematic transition curve adopts a zigzag path of rising and falling values and behaves in
the usual established manner. The nematic–isotropic transition curves for odd and even
homologues initially rise and then descend as series is ascended with exhibition of an odd-
even effect. The transition temperatures for the odd members are relatively higher than the
even members. The N-I transition curves for the odd and even homologues merge into each
other at the hexyloxy homologue and then a single curve results from and beyond hexyloxy
homologue. Thus, the N–I transition curve behaves in a normal manner. Mesomorphic
behavior of the present series varies from homologue to homologue with alternation of
transition temperatures. The novel homologous series is nematogenic without exhibition of
a smectogenic mesophase. The nematogenic mesophase length varies between 17◦C and
72◦C giving a wide degree of mesomorphism and a high melting type. Disappearance of
dimerization between two molecules of 4-n-alkxoy benzoic acids is due to the breaking of
hydrogen bonding on esterification. 4-Hydroxy-4’-methoxy benzyl cinnamate (m.p-204◦C,
yield 33%) is a nonliquid crystal component, but on linking it with 4-n-alkoxy benzoic acids
through their acid chlorides increases molecular length and the lateral attractions that result
in inducing nematogenic mesomorphism throughout the entire series with elimination of

14
B. H. Patel et al.
Figure 1. Phase behavior of series. Series: 4-[4’-n-Alkoxy benzoyloxy]-4”-methoxy benzyl
cinnamates.
smectogenic character from the smectogenic homologues (C7–C16) of 4-n-alkoxy benzoic
acids and induced nematogenic character in nonmesomorphic homologues of 4-n-alkoxy
benzoic acids (C1 and C2). Elimination of smectogenic character from 4-n-alkoxy benzoic
acids on esterification is attributed to the unsuitable magnitudes of molecular rigidity and
flexibility which hinders the formation of lamellar packing of molecules in their crystal
lattice. However, the magnitudes of molecular rigidity and flexibility are sufficient for
all the members of a series to maintain suitable magnitudes of intermolecular end-to-
end attractions which allow statistically parallel orientational order of molecules within
definite range of temperatures. Thus, nematic mesophase formation is favored to appear.

Mesomorphism Dependence on Molecular Flexibility
15
Table 3. Average thermal stability in ◦C
Series→
Series 1
Series X
Smectic-nematic or
Smectic-isotropic
Commencement of smectic phase
Nematic-Isotropic
Commencement of nematic phase
Total mesophase
144.1
(C6–C16)
C6
—
211.54 (C1–C16)
C1
171.4 (C5–C16)
C5
17◦C to 72◦C
C14 C13
33◦C to 53◦C
C6 C16
Range from t1 to t2
Alternation of transition temperatures from homologue to homologue in a series and the
appearance of odd-even effect in N-I transition curve is due to the sequential addition
of methylene unit or units in n-alkyl chain bonded to phenyl ring through oxygen atom.
Disappearance of odd-even effect from and beyond hexyloxy and higher homologues with
longer n-alkyl chain is attributed to the coiling, bending, flexing, or coupling of n-alkyl
chain with the major axis of the core structure of higher homologue molecules. Variations
of mesomorphic behaviors from homologue to homologue in present series is attributed
to the changing number of carbon atoms in CnH2n+1 chain of left terminal end group
keeping right ended –OCH3 terminal end group unchanged. Higher values of melting and
transition temperatures (Table 2) are due to the linear lath like shape and presence of highly
polar –OCH3 end group relatively longer size of molecules without lateral substitution
that reduces intermolecular closeness and raises intermolecular attractions. Consequently,
a high magnitude of heat energy, i.e., higher temperature is required for disruptions of
molecules. Higher molecular rigidity due to presence of conjugated double bond containing
central group, withstands externally exposed thermal vibrations and increases nematogenic
mesophase length maximum of 72◦C at the propyloxy homologue. Following Table 3
represents some mesophase behaviors of present series as under in comparative manner
with structurally similar homologous series-X [21] as shown in Fig 2.
Homologous series-X chosen for comparison and presently investigated novel series-1
are structurally similar (Fig. 2) and identical with respect to three phenyl rings and two
central bridges COO and CH CH COO CH2- sharing their contribution mainly
to the molecular rigidity in equal proportion from series to series. However, the molecular
flexibility by –OR, OCH3, and H are varied from series to series for same homologue
and from homologue to homologue in the same series. Therefore, suitable magnitudes
of anisotropic forces of intermolecular end-to-end and lateral attractions are varied from
series to series for the same homologue and homologue to homologue in the same series.
Thus, variations in mesomorphic behaviors and the degree of mesomorphism are attributed
Figure 2. Structurally similar homologous series.

16
B. H. Patel et al.
to the changing molecular part of the series 1 and X under comparison, affecting molec-
ular flexibility in combination with molecular rigidity. Changing molecular flexibility by
n-alkyl chain (CnH2n+1 = R-), keeping –OCH3 or –H unchanged, vary mesogenic properties
from homologue to homologue in the same series but variation in flexibility by replacement
of –H (series-X) by –OCH3 (series-1) cause variations in mesogenic properties for the same
homologue from series to series. Table 3 represents the difference of thermal stabilities,
commencement of mesophase or mesophases, mesophase lengths, or range etc. as under.
• Homologous serie-1 is entirely nematogenic without exhibition of smectogenic
property, whereas homologous series-X is predominantly nematogenic and partly
smectogenic.
• Nematogenic mesophase commences from the very first member of series-1, while
it commences from the fifth member of a series-X.
• Smectic mesophase commences from a sixth member of a series-X, while it does
not commence till the last member of series-1.
• Mesophase length of a series-1 is relatively wider than a series-X.
• Thermal stability for the nematogenic mesophase formation of series-1 is higher
than a series-X chosen for comparison.
• Smectogenic mesophase stabilizes in case of series-X with absence of mesophase
formation (either smectic or nematic phase) prior to pentyloxy homologue of a
series-X, while mesophase formation occurred (only nematic) from very first to last
member of a present series-1 with none of the member of series as nonmesomorphic.
Suitable magnitudes of anisotropic forces of intermolecular attractions (either only end-to-
end or including lateral) and favorable closeness as a consequence of molecular rigidity
and flexibility can induce either only nematic or only smectic or smectic in addition
to nematic property. The observed differences of mesomorphic behaviors for the same
homologue from series to series (1 to X) are attributed to the difference between two right
hand sided terminal end groups in which –H (series-X) is replaced by –OCH3 (series-
1). The group polarity of –OCH3 terminal and its contribution to molecular length are
obviously more than a terminal –H. Therefore, suitable magnitudes of anisotropic forces of
intermolecular end to end attractions, extent of noncoplanarity tendency to form lamellar
packing of molecules in their crystal lattices for the same homologue vary from series 1 to
X. Thus, the resistivity against externally exposed thermal vibrations, thermal stabilities,
commencement of mesophase formation mesomorphic phase length and the type or types
of mesophase vary accordingly. The presence of penta atomic –OCH3 terminal end group
though favors the statistically parallel orientational order of molecular floating on the
surface with higher resistivity, facing exposed thermal vibrations more effectively than a
terminal end group –H of series-X to stabilize and to facilitate nematic phase, but it hinders
the formation of lamellar packing of molecules (of series-1) to stabilize and facilitate three-
dimensional network in solid crystal or two-dimensional molecular network as sliding
layered network in floating condition due to unsuitable extent of molecular noncoplanarity.
Thus, molecules of entire series-1 are only nematogenic without exhibition of smectic
property. However, on replacing penta atomic –OCH3 (series-1) by monoatomic terminal
end group –H offers, relatively unhindered and favorable intermolecular anisotropic forces
of attractions of such a suitable magnitudes, that, two-dimensional molecular network as
sliding layers floating on the surface are facilitated to form a smectic mesophase from
the hexyloxy homologue of series-X, in addition to nematogenic mesophase. Thus, apart
from more or less magnitudes of anisotropic forces of intermolecular attractions to induce
liquid crystal property, a suitable magnitudes of anisotropic forces of intermolecular end

Mesomorphism Dependence on Molecular Flexibility
17
to end or/and lateral attractions required to induce smectic or/and nematic phase which is
an important, as a consequence of favorable molecular rigidity and/or flexibility depending
on molecular structure. Hence, excessive polarity and flexibility of –OCH3, terminal end
group can enhance thermal stability for nematic, early commencement of nematic phase
and relatively wider nematogenic phase length, but, fails to build up lamellar packing of
molecules in their crystal lattices to induce smectic mesophase as compared to terminal
end group –H of series-X. The molecules of series-X though induces smectic mesophase,
in addition to nematic phase but mesophase length range is relatively shorter than series-1,
because of the low resistivity against externally exposed thermal vibrations due to weakly
polar end group –H as compared to –OCH3.
Thus, variations in mesomorphic behaviors from homologue to homologue in the same
series and, the series to series for the same homologue are due to the changing number of
carbon atoms in n-alkyl chain of –OR terminal end group and varying terminals –OCH3,
-H for the same homologue from series to series, respectively.
Conclusions
• Group efficiency order derived for smectic and nematic on the basis of (i) thermal
stability and (ii) the early commencement of smectic and nematic phase are as under.
i. Smectic: H > OCH3
Nematic: OCH3 >
H
ii. Smectic: H > OCH3
Nematic: OCH3 >
H
• Presently investigated ester homologous series using para-substituted benzyl alco-
hol is entirely nematogenic without exhibition of smectogenic character, whose
mesophase lengths are relatively wider and high melting type.
• Suitable magnitudes of anisotropic forces of intermolecular attractions as a con-
sequence of favorable molecular rigidity and flexibility can induce possibility of
mesophase formation in a substance.
• Molecular rigidity and flexibility of a molecular structure are very sensitive and
susceptible to induce liquid crystal property in a substance.
• Variations in mesomorphic behaviors from homologue to homologue in the same
series depend on changing part of a molecule and solely depend upon molecular
structure.
• Presently investigated novel substances may be useful as bioactive molecules.
Acknowledgments
The authors acknowledge thanks to the Green Circle Inc. Lab for research facilities services
as and when needed. The authors also thank Dr. Umed Bhoya for his valuable helping hand
and microscopic facility. Thanks are due to the Sophisticated Analytical Instrumentation
Facility, Punjab University, Chandigarh for analytical services.
References
[1] Demus, D. (1988). 100 years of liquid crystal chemistry. Mol. Cryst. Liq. Cryst., 165, 45–84
[2] Demus, D. (1989). Plenary lecturers: 100 years of liquid crystal chemistry, Thermotropic liquid
crystals with conventional and unconventional molecular structure. Liq. Cryst., 5, 75–110.

18
B. H. Patel et al.
[3] Tadwee, I., Dr. Shahi, S., Ramteke, V., & Syed, I. (2012). “Liquid Crystals Pharmaceutical
Application: A Review, “IJPRAS.” Int. J. Pharma. Res. Allied Sci., 1(2), 6–11.
[4] Gray, G. W., & Windor, P. A. (1974). Liquid Crystals and Plastic Crystals. Ellis Horwood Ltd.:
Chichester; Halsted Press: A division of John Wiley and Sons, Inc. New York, London. Vol. 1,
Chap. 7, pp. 327–356.
[5] Darshan Raj B. K. et al. (2013). Derpharma Chem., 5(3), 305–317
[6] (a) Iwabuta, K. et al. (2013). Review, Molecules 2013, Appl. Biomater. Liq. Cryst., 18,
4703–4717, doi: 10. 3390/ molecules 18044703. (b) European Patent EP0117502 B1, Pro-
cess of producing benzyl ester of aromatic hydroxy carboxylic acids, Example-1 page 1, date
of publication on 19-11-1987.
[7] Mossety–Leszczak, B., Galina, H., & Wlodarsko, M. (2011). Phase transitions, 84(1), 15–28.
[8] Gray, G. W., & Windor, P. A. (1974). Liquid Crystals and Plastic Crystals. Ellis Horwood Ltd.:
Chichester; Halsted Press: A division of John Wiley and Sons, Inc. New York, London. Vol. 1,
Chap. 4. pp. 103–175.
[9] Gray, G. W. (1962). Molecular Structure and Properties of Liquid Crystals. Academic Press:
London.
[10] Gray, G. W. (1979). Liquid Crystals and Molecular Structure in Molecular Physics, Academic
Press: London. pp. 1–30.
[11] Gray, G. W., & Jones, B. (1954). Mesomorphism and Chemical Constitution, part-II, The
trans-p-n-alkoxy cinnamic acids. J. Chem. Soc., 1467–1470.
[12] Attarot, G. S., Date, R., Imrie, C. T., Luckhurst, G. R., Reskilly, S. J. et al. (1994). Liq. Cryst.,
16, 529–581.
[13] Marcelis, A. T. M., Koudjs, A., Karaczmarzyk, Z., & Sudholter, E. J. R. (2003). Liq. Cryst., 30,
1357–1364.
[14] (a) Hird, M., Toyne, K. J., Gray, G. W., Day, S. E., & McDonnell, D. G. (1993). Liq. Cryst., 15,
123. (b) Hird, M., Toyne, K. J., & Gray, G. W. (1993). Liq. Cryst., 14, 741
[15] Gonzalez, Y., Ros, M. B., Serrano, J. L., & Perezjubind, A. (1998). Liq. Cryst., 18, 751.
[16] Marcos, M., Omenat, A., Serrano, J. L., & Ezcurra, A. (1992). Adv. Mater., 4, 285.
[17] Collings, P. J., & Hird, M. (1997). Introduction to Liquid Crystal Chemistry and Physics. Taylor
and Francis: New York
[18] Dave, J. S. & Vora, R. A. (1978). Liquid Crystals and Ordered Fluids, Johnson, J. F. & Porter,
R. S. (Eds.) Plenum Press: New York.
[19] European Patent EP0117502 B1, Process of producing benzyl ester of aromatic hydroxy car-
boxylic acids, Example-1 page-4, date of publication on 19-11-1987.
[20] (a) Ganatra, K. J. & Doshi, A. V. (1999). Proc. Ind. Acad. Sci. (Chem. Sci), 4(11), 562. (b) Suthar,
D. M. & Doshi, A. V. (2012). Mol. Cryst. Liq. Cryst., 569, 64. (c) Chouhan, B. C. & Doshi, A.
V. (2011). Der Pharma. Chem., 3(1), 172.
[21] Manuscript of research paper, entitled, “Mesomorphism and Molecular Structure in an Ester Ho-
mologous Series: 4-(4’-n-Alkoxy Benzoyloxy) Benzyl Cinnamates” submitted for publication
through Taylor and Francis, Mol. Cryst. Liq. Cryst. LC-MH236, date 1.12.2013.