Synthesis and mesomorphic properties of laterally fluorinated alkyl 4′′-alkylterphenyl-4-yl carbonate liquid crystals

Article abstract of DOI:10.1039/c3tc31461h

Fifteen series of homologues of a variety of mono-, di- and trifluorosubstituted alkyl 4′′-alkylterphenyl-4-yl carbonates have been synthesized and their mesomorphic properties have been determined. From among 95 prepared compounds, 40 pure nematogens have been found, as well as 55 mesogens with orthogonal and tilted smectic phases in broad temperature ranges. The type and combination of the LC phase strongly depend on the position and number of the fluorine atoms. Physical properties and correlations between the molecular core fluorosubstitution, the length of the terminal chains and the type and sequence of the liquid crystalline phases, have been determined. The compounds are useful for the formulation of nematic mixtures as well as ferroelectric ones.

Full text of DOI:10.1039/c3tc31461h

Journal of
Materials Chemistry C
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PAPER
Synthesis and mesomorphic properties of laterally
fluorinated alkyl 400-alkylterphenyl-4-yl carbonate
Cite this: J. Mater. Chem. C, 2014, 2,
liquid crystals†
891
a
Artur Chołuj, Przemysław Kula,a Roman Dabrowski,a Marzena Tykarskaa
*
˛
and Leszek Jaroszewiczb
Fifteen series of homologues of a variety of mono-, di- and trifluorosubstituted alkyl 400-alkylterphenyl-4-yl
carbonates have been synthesized and their mesomorphic properties have been determined. From among
95 prepared compounds, 40 pure nematogens have been found, as well as 55 mesogens with orthogonal
and tilted smectic phases in broad temperature ranges. The type and combination of the LC phase strongly
depend on the position and number of the fluorine atoms. Physical properties and correlations between the
molecular core fluorosubstitution, the length of the terminal chains and the type and sequence of the liquid
crystalline phases, have been determined. The compounds are useful for the formulation of nematic
mixtures as well as ferroelectric ones.
Received 26th July 2013
Accepted 23rd October 2013
DOI: 10.1039/c3tc31461h
www.rsc.org/MaterialsC
In this paper, we describe the synthesis of alkyl 400-alkylter-
phenyl-4-yl carbonates laterally substituted with uorine atoms
Introduction
at different core positions and with different terminal chain
lengths, expressed by a common structural formula (Fig. 1,
where X1–6 is a hydrogen or uorine atom), with up to three
uorine atom substitutions. Studies were also conducted on the
relationship between the structure and its mesomorphic and
physical properties. For the purposes of clarity, the homologue
series have been named 1.mn to 15.mn (see Fig. 2), where the
indices n and m refer to the different lengths of the alkyl chains
for successive members within a particular series. Obtained
compounds are valuable components of nematic and ferro-
electric mixtures, which are named in our patent application20
and which will be the subject of a future report.
Laterally uorosubstituted dialkyl and alkyl-alkoxy terphenyl
derivatives were rstly designed for ferroelectric mixtures.1–4
Subsequently reported terphenyls with short chains were
considered as medium birefringent mixture components for
negative dielectric anisotropy nematics crucial to many applica-
tions,5–7 mainly in vertical alignment (VA), and especially in
projection microdisplays and electrically controlled birefringence
(ECB) modes. In addition, they are very important components
for high birefringent dual frequency addressed mixtures,8–10 and
they are also of considerable interest in the infra-red and THz
range.11 The terphenyl core was also found to be suitable for use
in antiferroelectric liquid crystals.4,12 Dialkyl, alkyl-alkoxy and
dialkoxy laterally uorosubstituted terphenyl derivatives have
been investigated in earlier studies,13,14 but until now there have
been no reports on alkyl carbonates linked with an alkyl uori-
nated terphenyl moiety. The carbonate group is well known for its
high chemical and photochemical stability, e.g. in poly-
carbonates,15–17 but is rarely used in the design of liquid crystal-
line compounds. Recently, an alkylbicyclohexyl family of nematic
materials incorporating a carbonate group with a very low ordi-
nary index below silica glass was prepared,18 which enabled
guidance of the light according to the total internal reection
mechanism in the liquid crystal photonic bres.19
Synthesis
The synthesised unsubstituted, mono-, di- and triuorosubstituted
compounds were prepared and are listed in Fig. 2.
In the synthesis of the carbonate derivatives, the crucial
semi-products were 400-alkyl-4-hydroxyterphenyls laterally
substituted with uorine atoms, which were synthesized from
the corresponding methoxy or ethoxy ethers, via HI or BBr3
ether cleavage. The main challenge in the preparation of the
short chain alkoxy ethers was the synthesis of the rigid
aInstitute of Chemistry, Military University of Technology, 00-908 Warsaw, Poland.
E-mail: arturcholuj@o2.pl; Tel: +48 511758820
bInstitute of Applied Physics, Military University of Technology, 00-908 Warsaw,
Poland
† Electronic supplementary information (ESI) available. See DOI:
10.1039/c3tc31461h
Fig. 1 Common structural formula for synthesized compounds.
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4-hydroxyterphenyl carbonates is presented in Schemes 1–6,
which show the synthetic pathway for all of the homologue
series presented here. In many cases, 3-alkyl-1-uorobenzene or
3-alkyl-1,2-diuorobenzene were prepared at the rst steps of
the synthetic pathways. The method described by Gray et al.2
was used at the beginning of the work, but other, shorter,
approaches have been more recently developed.21 An ortho-
lithation procedure was used to synthesize iodo derivatives and
boronic acids, and the commonly-used Suzuki–Miyaura
coupling22 was then adopted to create bonds between the
benzene rings. The nal carbonates were prepared following the
reaction of alkylterphenols with alkyl chloroformate (Scheme 2).
Examples of the general synthetic methods are given in the
experimental section. Details on the synthesis, yields and proper-
ties of intermediates and nal products can be found in the ESI.†
Mesomorphic properties
The phase transition temperatures and enthalpies of the
products were measured using a diffeꢁre1ntial scanning calo-
rimeter (SETARAM 141) at a 2 ꢀC min rate. Liquid crystal
phases were identied by microscopy pattern studies using a
Linkam THMS-600 heating stage, together with a polarizing
microscope (Olympus BX52), and they were conrmed by
miscibility studies. The results are shown in Tables 1–3.
Compounds 1.31 and 1.32 have a nematic mesophase and
orthogonal smectic A and E phases. With a longer terminal chain
(1.33), the smectic B phase also appears. Similar phasic properties
are observed in the monouorinated compounds, 2.mn, which
have orthogonal smectic A, B, and E phases. The nematic phase is
only seen in a narrow range for compound 2.32 in this series.
Compounds 5.mn display similar properties, but the nematic
phase is in a broader temperature range and higher order phases
appear only with longer terminal chains and they are usually
monotropic. Other monouorosubstituted compounds such as
3.mn have a nematic phase in a broad temperature range, and
smectic A, and monotropic B and E phases are observed with
longer terminal chains (3.51–3.53). The nematic phase for
compounds 4.mn is in the broadest temperature range (over 100
degrees) among the monouoroterphenyl carbonates.
With respect to the diuorosubstituted compounds, the
homologue series 7.mn, 10.mn, 11.mn, 12.mn and 13.mn only
show
a nematic phase in a broad temperature range.
Compounds 11.mn and 13.mn have the lowest melting point
(for 11.53 and 13.54, 50.1 ꢀC and 42 ꢀC, respectively).
Compounds 6.mn and 9.mn show an additional smectic A
phase, while compound 6.59, which has longer terminal chains
(pentyl and nonyl), has a smectic C phase. Series 8.mn
compounds have nematic and smectic C phases. Higher
ordered phases appear here with longer terminal chains. Tri-
Fig. 2 Series of prepared homologues.
molecular core, especially in the case of series 13.mn, where the uorosubstituted carbonates have a marginally higher melting
middle ring of the terphenyl core was non-substituted while the temperature compared to diuorosubstituted carbonates. The
other two rings were 2 and 200 monouorosubstituted, due to lowest melting temperature, 68 ꢀC, is observed for 14.53.
the fact that uorine-directed lithiation is one of the main Unexpectedly, these compounds only show a nematic phase.
reactions used for the functionalization of intermediates. For all
Fig. 3 and 4 show how the position and number of uorine
prepared series, different approaches were analysed and opti- atoms inuence the phase properties of carbonates with the
mized. The optimized method for the synthesis of alkyl 400-alkyl- same terminal chain length.
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Scheme 1 The synthetic method for preparation of semi-products for series 4.mn, 8.mn, and 11.mn.
Scheme 2 Final step of the synthetic procedure.
point to a greater extent than the alkoxy group, and it induces a
larger increase in the clearing point compared to the alkyl group
(see Table 4).
The position of a uorine atom or atoms is crucial for the
type of mesophase observed. Previous studies on dialkyl and
alkylalkoxyuoroterphenyls2,6,10 show that uorine in the 3 or 300
outer position promotes orthogonal and/or tilted smectic pha-
ses and the same is observed for alkyl terphenyl carbonates, but
only for the 3 substitution (see the compounds of series 2.mn,
Discussion
As can be seen from the data, the position of the uorine atoms
in the terphenyl core has a much greater inuence on the type of
mesophase observed than the length and type of terminal
chains (alkyl–alkyl; alkyl–alkoxy; alkyl–alkyl carbonate). If
compounds with identical chain lengths are compared, we can
see that they have the same mesophases but the carbonate
chain promotes the nematic phase and decreases the melting
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Scheme 4 The synthetic method for preparation of semi-products for
series 10.mn
12.mn, and 13.mn, with uorine in positions 20,30; 200,20; 200,30;
2,20; and 2,200, respectively, shows that these positions are the
most favorable for formation of a nematic phase for compound
with two uorine atoms. The triuorosubstituted homologue
series (14.mn and 15.mn) only exhibit a nematic mesophase, but
the clearing points are much lower, and therefore, the
Scheme 3 The synthetic method for preparation of semi-products for
series 7.mn and 15.mn.
which exhibit only the orthogonal smectic phases A, B and E). temperature range of the nematic phase is observed from 40 to
2,3-Diuorosubstituted alkylterphenyl carbonates (6.mn) have 60 degrees.
an orthogonal A phase and a nematic phase, while 200300-
The inuence of the terminal chain length on mesophase
diuorosubstituted compounds (8.mn) have a tilted smectic C stability is typical – with longer chains the clearing points
phase. Monouorosubstituted compounds with the uorine in decrease, as well as the melting points. In some cases, for
position 200 (series 4.mn) favour the nematic phase, but at low example, series 3.mn, 4.mn, 5.mn and 13.mn, the drop in
temperatures a monotropic tilted smectic phase is observed. melting point with a change in index n from 3 to 4 is especially
The diuorosubstituted homologue series 7.mn, 10.mn, 11.mn, large, but in other cases such as series 8.mn, 11.mn or 14.mn, for
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In unsubstituted terphenyl carbonates, the formation of a
higher order orthogonal smectic phase (A, B, E) is favoured.
Addition of uorine atoms to the ring closest to the carbonate
group only does not disturb this order. Introduction of uorine
atoms to the ring furthest away from the carbonate group leads
to the formation of higher ordered tilted phases. Other combi-
nations of uorine atom positions result in a nematic phase.
In terms of applications, the most benecial properties are
observed in compounds in which the uorine atom or atoms are
located at a greater distance from the carbonate group (when
added to the le or central benzene rings). Such carbonates
have a broad range nematic phase or nematic and smectic C
phases. Compounds with uorine atoms close to the carbonate
group have orthogonal smectic E, B, and A phases in a broad
temperature range.
Experimental
A
Shimadzu GC-2010 series gas chromatography system
equipped with a capillary column and a quadrupole mass
selective detector was used for purity assessment and MS
analysis. Proton (1H) and carbon (13C) nuclear magnetic reso-
nance (NMR) spectra in CDCl3 were collected using a Varian 500
spectrometer. HRMS spectra were collected using an AutoSpec
Premier (Waters) with the gas chromatography system HP 7890
(Agilent). The purity of the nal products was >99.5%.
General method for preparation of intermediates and nal
products
Preparation of 3-alkyl-1-uorobenzenes and 3-alkyl-2,3-
diuorobenzenes. The general method for the synthesis of
these compounds is presented using 1-uoro-3-propylbenzene
(compound 4) as an example.
A piece of iodine crystal was added to a ask containing
magnesium turnings (13.2 g, 0.543 mol) under nitrogen atmo-
Scheme 5 The synthetic method for preparation of semi-products for
series 13.mn.
compounds with index m ¼ 5, the increase in index n from 3 to 4 sphere, and a solution of 1-bromo-3-uorobenzene (1) (95 g, 0.542
only causes a small increase in the melting point. mol) in dry tetrahydrofuran (300 ml) was then added dropwise,
There is clearly competition between the inuence of terminal keeping the mixture in a gentle reux. The reaction mixture was
chain length and the inuence of uoro substituents on meso- stirred at reux for 2 h, then cooled to ꢁ78 ꢀC in a dry ice–acetone
morphic properties. Looking at series 6.mn and 8.mn, it is bath, and propionaldehyde (33.6 g, 0.58 mol) was added dropwise
apparent that the compound with the longest terminal chain while maintaining the temperature below ꢁ70 ꢀC. Aer the addi-
(6.59) has a SmC phase although the position of the uoro tion of the aldehyde, the cooling bath was removed and the reac-
substituents promotes orthogonal phases. In the case of tion was le overnight. Tetrahydrofuran was evaporated under
compound 8.31, although the uoro substituents promote tilted reduced pressure and the residue was acidied with a 10% solu-
phases, its short terminal chains ensure it will have a SmA phase. tion of hydrochloric acid. The organic phase was separated,
washed twice with water and dried over magnesium sulphate. The
1-(3-uorophenyl)propanol was distilled at a pressure of 18 Torr,
b.p. 117 C. The yield of alcohol was 66% (60 g). The obtained
Conclusions
ꢀ
Some alkyl alkylterphenyl carbonates have more favourable alcohol and p-toluenesulfonic acid (2 g, 0.12 mol) was heated in
mesomorphic properties than 4,400-dialkyl or 400-alkyl-4-alkoxy toluene (300 ml) at reux until evaporation of the water was
substituted terphenyls and their mesogenic properties can be complete. Toluene was distilled off using a vacuum evaporator.
exploited for practical applications. Mixtures with nematic or The residue was distilled at 18 Torr, b.p. 110–112ꢀC. To the solu-
smectic C phases in a broad temperature range may be formu- tion prepared from the obtained alkene, acetic acid (30 ml), ethyl
lated. The mesomorphic properties of the carbonates depend on acetate (50 ml) and the catalyst (10% palladium on activated
the number of uorine atoms as well as their position relative to carbon (2 g)) was added. The mixture was stirred and a gas burette
each other and in relation to the carbonate group.
with hydrogen was connected. The reaction temperature increased
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Scheme 6 The synthetic method for preparation of semi-products for series 1.mn, 2.mn, 3.mn, 5.mn, 6.mn, 9.mn, 12.mn, and 14.mn.
spontaneously to 30 ꢀC. When hydrogen absorption was complete,
The 1-uoro-3-pentylbenzene, 1-uoro-3-ethylbenzene, 2,3-
the catalyst was ltered off, and the mixture was diluted with diuoro-3-propylbenzene and 2,3-diuoro-3-pentylbenzene
water. The organic layer was separated, washed with water and were obtained in the same way but in the case of the two last
dried over magnesium sulphate. The solution was distilled and the compounds, a lithium intermediate was used instead of a
3-uoro-1-propylbenzene fraction was collected at a temperature of Grignard reagent. The preparation of the lithium derivatives is
160 C at atmospheric pressure. Lit. 162 C.25 Yield 42% (31 g), described further on – see the method of preparation of 2-u-
ꢀ
ꢀ
purity 99.0%, MS m/z 136 (M+), 135, 115,109, 96, 83, 75, 63, 57, 39. oro-1-iodo-4-propylbenzene (9).
896 | J. Mater. Chem. C, 2014, 2, 891–900
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Table 1 Phase transition [ꢀC], followed by enthalpy [kJ molꢁ1] for unsubstituted and monofluorosubstituted terphenyl carbonates
Core
m
n
Cr
SmE
SmG
SmB
SmC
SmA
N
Iso
1
1
1
2
2
2
2
2
2
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
3
3
3
3
3
3
5
5
5
3
3
3
3
5
5
5
2
2
2
2
3
3
3
5
5
5
5
3
5
5
5
5
1
2
3
1
2
3
1
2
3
1
2
3
4
1
2
3
1
2
3
4
1
2
3
1
2
3
4
3
1
2
3
4
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
92.5, 7.6
85.5, 3.8
79.2, 6.4
*
*
*
*
*
*
*
*
*
232.1, 10.0
225, 7.5
*
*
*
*
*
*
*
*
*
245.1, 1.6
240.8, 5.0
235.5, 6.4
212.8, 4.4
209.4, 5.4
200.6, 6.7
207.2, 7.5
203.8, 7.5
197.3, 7.6
*
*
*
261.6, 1.0
249.1, 0.7
238.5, 1.1
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
220.8, 3.2
172.5, 7.0
165.5, 3.8
157.0, 2.9
154.7, 2.6
144.9, 2.1
140.3, 2.0
*
224.0, 4.3
141.6, 8.8
125.5, 10.9
119.8, 11.7
86.2, 12.9
91.9, 9.3
95.9, 10.2
110.1, 27.7
106.3, 28.0
99.3, 21.9
79.7, 20.2
88.3, 21.6
76.2, 20.3 (*)
67.8, 14.9 (*)
88.4, 18.2
102.2, 28.0
91.6, 20.8
*
*
*
168.0, 2.2
162.0, 1.9
166.0, 2.5
163.8, 2.9
162.0, 3.1
*
211.7, 1.3
*
*
*
*
*
*
*
*
*
*
*
*
*
210.1, 1.0
195.8, 1.1
181.9, 0.8
174.2, 0.7
194.8, 0.8
182.7, 0.8
171.0, 0.8
200.4, 0.7
184.2, 0.7
168.2, 0.5
159.8, 0.7
207.0, 0.7
193.0, 0.8
173, 0.9
195.8, 0.7
179.0, 1.0
168.3, 0.8
161.5, 0.8
181.3, 0.8
192.5, 0.9
179.6, 1.1
167.7, 1.0
161.8, 0.9
*
*
*
123.0, 0.3
126.6, 0.3
125.3, 0.3
(54.7), 7.5
(50.2), 9.0
(*)
(*)
(66.5), 1.9
(62.9), 1.3
(*)
(*)
(71.1), 6.5
(62.2), 6.7
57.0, 31.0
85.0, 19.3
88.0, 23.1
(*)
(66.8), 12.0
(80.7), 6.6
82.0, 23.5 (SmK) (*) (73.1), 1.5 (*)
84.0, 19.5
72.8, 26.8
67.6, 26.5
57.9, 15.7
107.1, 20.9
67.1, 16.6
87.8, 24.2 (*)
76.6, 22.9 (*)
56.2, 14.8 (*)
*
*
*
*
*
*
*
*
*
*
(*)
*
(55.0), 2.1
65.8, 2.9
(*)
*
(66.0), 0.3
76.5, 0.7
*
86.7, 4.9
*
*
*
*
113.9, 1.1
104.2, 0.7
97.1, 0.6
72.1, 0.2
(79.0), 2.8
(63.2), 1.9
(46.9), 1.2
(*)
(*)
*
(83.0), 1.8
(78.6), 1.7
66.9, 1.8
boronic acid (22.1 g, 0.091 mol), water (100 ml) and acetone
(300 ml) under nitrogen atmosphere was stirred and boiling was
maintained for 20 min. The mixture was cooled to 40 ꢀC and the
catalyst (palladium acetate (0.1 g)) was added. The temperature
rose spontaneously by several degrees and the solution changed
colour to brown. The mixture was reuxed for 6 h, then it was
cooled, poured onto water and the crude product was ltered off
under reduced pressure. The product was recrystallized from
ethanol. Yield 81% (19.7 g), purity 99.5%, MS m/z 334 (M+), 305,
277, 248, 183, 29.
Preparation of ortho-iodo uorophenyl and uorobiphenyl
derivatives. The method is given using the example of 2-uoro-
1-iodo-4-propylbenzene (compound 9). A mixture composed of
3-uoro-1-propylobenzene (3) (30 g, 0.217 mol) and dry tetra-
hydrofuran (300 ml) was cooled to ꢁ78 ꢀC using a dry ice–
acetone bath under nitrogen atmosphere. 170 ml of sec-butyl-
lithium (1.3 M solution, 0.221 mol) was added dropwise,
keeping the temperature below ꢁ70 ꢀC. The mixture was stirred
for 2 h at ꢁ78 ꢀC and a solution of iodine (55.12 g, 0.217 mol) in
dry tetrahydrofuran (200 ml) was then added dropwise, while
maintaining the temperature at ꢁ70 ꢀC. The mixture was
allowed to heat up to room temperature. Tetrahydrofuran was
evaporated under reduced pressure, and the residue was treated
with a solution of sodium sulphite followed by water washing
(three times). The organic layer was separated and dried over
magnesium sulphate. The compound was distilled at a pressure
For the other compounds, coupling was conducted in similar
conditions except for the synthesis of compound 10 which was
conducted in toluene in the presence of the catalyst SPhos–Pd
and the base K3PO4.
Deprotecting the hydroxyl group in terphenyl derivatives
ꢀ
of 0.4 Torr, b.p. 60 C. Yield 75% (43 g), purity 99.8%, MS m/z
264 (M+), 235, 128, 108, 29.
The procedure is given using the example of 200-uoro-4-
In the case of 2,3-diuoro-1-iodophenyl derivatives, n-butyl- hydroxy-400-propyl-[1,10:40,100]-terphenyl (compound 25).
lithium was used.
To a mixture of 20-uoro-4-methoxy-40-propyl-[1,10:40,100]
Suzuki–Miyaura coupling reactions. This is described using terphenyl (18 g, 0.0562 mol), acetic acid (200 ml) and a
the synthesis of 2-uoro-400-ethoxy-4-propyl-[1,10:40,100]terphenyl hydroiodic acid solution (38 g of 57%, 0.17 mol), acetic
(compound 18) as an example.
anhydride (113 g, 1.11 mol) was added dropwise. The
A mixture of 3-uoro-4-iodo-1-propylbenzene (20 g, 0.076 mol), reaction mixture was reuxed for two days, and then
potassium carbonate (31.46 g, 0.228 mol), 40-ethoxybiphenyl-4-yl poured onto ice and water. The product precipitate was
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Table 2 Phase transition [ꢀC], followed by enthalpy [kJ molꢁ1] for difluorosubstituted terphenyl carbonates
Core
m
n
Cr
SmH
SmG
SmC
SmA
N
Iso
6
6
6
6
6
6
6
7
7
7
7
7
7
7
8
8
8
8
8
8
8
8
8
8
3
3
3
5
5
5
5
3
3
3
5
5
5
5
3
3
3
3
3
5
5
5
5
5
3
3
3
3
3
3
5
5
5
5
3
3
3
3
5
5
5
5
3
3
3
3
5
5
5
5
5
1
2
3
1
2
3
9
1
2
3
1
2
3
4
1
2
3
4
7
1
2
3
4
7
2
3
1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
2
1
2
3
4
5
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
155.2, 35.1
122.8, 22.5
106.5, 21.2
119.8, 25.5
100.6, 14.8
84.9, 23.9
66.4, 34.1
139.0, 32.3
119.4, 31.3
95.3, 25.5
78.0, 29.3
73.4, 33.7
68.9, 28.2
54.9, 35.0
112.0, 23.4
121.8, 22.6
113.6, 14.8
79.3, 11.3
67.5, 21.5
105.2, 27.9
86.8, 27.8
73.3, 24.2
82.7, 25.2
67.6, 18.9
89.0
*
*
*
*
*
*
155.7, 1.3
149.9, 1.4
139.0, 1.3
160.0, 2.3
152.8, 1.8
144.4, 1.6
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
198.0, 1.0
187.7, 0.9
174.7, 0.9
183.9, 1.2
174.0, 1.0
164.3, 1.0
132.6, 0.8
200.8, 1.0
188.5, 0.9
171.1, 0.8
183.5, 0.9
171.0, 0.8
158.8, 0.7
152.5, 0.8
206.8, 0.8
191.5, 0.7
177.6, 0.7
169.8, 0.8
153.5, 0.4
194.9, 0.7
182.8, 0.7
172.0, 0.8
162.1, 0.8
149.6, 0.9
166.6
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
95.8, 0.2
*
118.1, 0.2
(*)
*
(114.2), 0.5
121.1, 1.6
125.8, 2.2
126.6, 1.5
*
*
101.4, 0.5
76.8, 1.2
*
*
103.9, 4.6
87.5, 11.5
*
*
*
*
*
*
112.0, 0.4
122.9, 0.8
127.2, 1.2
133.2, 2.1
(*)
*
(65.8), 2.1
78.5, 1.1
9a
9a
10
10
10
10
10
10
10
10
11
11
11
11
11
11
11
11
12
12
12
13
13
13
13
13
13
*
*
118.5
109.5
77.5
153.1
111.8, 36.6
80.7, 30.8
59.6, 26.8
53.7, 23.6
78.7, 28.6
58.8, 23.5
56.5, 24.6
52.2, 24.2
86.2, 32.9
96.3, 27.4
79.5, 32.3
75.1, 31.6
65.1, 21.8
62.4, 24.3
50.1, 23.5
53.3, 26.3
120.0, 28.2
115.8, 27.4
83.0, 26.4
77.4, 23.0
86.6, 30.0
69.5, 24.4
63.3, 26.0
42.0, 23.5
52.2, 31.9
176.1, 1.0
159.0, 0.9
142.7, 0.8
135.7, 1.1
161.0, 1.0
147.7, 1.1
134.0, 1.1
128.6, 1.2
165.3, 1.2
148.9, 1.3
130.9, 1.1
122.3, 1.0
150.4, 1.2
137.5, 1.1
121.2, 1.0
115.6, 1.2
168.3, 1.0
152.1, 1.0
136.5, 1.0
155.7, 1.0
159.2, 1.1
145.1, 1.2
132.8, 1.2
127.2, 1.2
122.5, 1.0
a
Temperatures from polarization microscopy.
ltered off, dried and recrystallized from
a hexane–
Preparation of ortho-uorophenyl and ortho-uorobiphenyl-
toluene solution 1 : 1. Yield 93% (16 g), purity 99.9%, MS m/z
306 (M+), 277, 248, 183, 139, 29; 1H NMR (200 MHz, CDCl3)
d 9.30 (1H, s, PhOH), 7.65–7.74 (2H, q, Ph), 7.62–7.69 (2H,
q, Ph), 7.12–7.18 (1H, d, Ph), 6.82–7.02 (4H, m, Ph), 2.58-2.68
(2H, t, CH2Ph), 1.52–1.71 (2H, m, CH2), 0.90–1.00 (3H,
t, CH3).
4-yl boronic acids
The procedure is given using the example of 3-uoro-40-
methoxybiphenyl-4-yl boronic acid (compound 15).
To a solution composed of 30-uoro-4-methoxybiphenyl (19.1
g, 0.095 mol) and dry tetrahydrofuran (200 ml) under nitrogen
898 | J. Mater. Chem. C, 2014, 2, 891–900
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Paper
Journal of Materials Chemistry C
Table 3 Phase transition [ꢀC], followed by enthalpy [kJ molꢁ1] for
trifluorosubstituted terphenyl carbonates
Core
m
n
Cr
N
Iso
14
14
14
14
14
14
14
14
14
15
15
15
3
3
3
3
5
5
5
5
5
3
3
3
2
3
4
5
1
2
3
4
5
1
2
3
*
*
*
*
*
*
*
*
*
*
*
*
100.2, 30.8
92.6, 28.9
74.1, 25.2
73.6, 28.3
86.3, 32.1
81.2, 27.5
68.2, 26.9
70.7, 27.7
76.5, 30.6
106.3, 24.8
102.6, 35.5
89.9, 24.3
*
*
*
*
*
*
*
*
*
*
*
*
141.7, 0.9
127.7, 0.9
120.4, 1.0
112.2, 0.9
141.7, 1.0
132.6, 1.0
120.5, 0.9
114.4, 1.0
107.6, 1.0
162.3, 0.9
147.5, 0.9
128.9, 0.8
*
*
*
*
*
*
*
*
*
*
*
*
Fig. 4 Mesomorphic properties of carbonates with m ¼ 5 and n ¼ 3. N
¼ nematic phase, SmA ¼ smectic A phase, SmC ¼ smectic C phase,
SmB ¼ smectic B phase, SmE ¼ smectice E phase, SmG ¼ smectic G
phase, SmH ¼ smectic H phase.
Table 4 Comparison of carbonates with dialkyl and alkyl-alkoxy
terphenyls
n
m
Z
Phase transition
5
5
6
4
—
OCOO
Cr 115 SmC 131,5 N 166,5 Iso5
Cr 58 SmH 65,8 SmC 77 N 162 Iso
Fig. 3 Mesomorphic properties of carbonates with m ¼ 3 and n ¼ 2. N
¼ nematic phase, SmA ¼ smectic A phase, SmC ¼ smectic C phase,
SmB ¼ smectic B phase, SmE ¼ smectice E phase, SmG ¼ smectic G
phase, SmH ¼ smectic H phase.
5
5
5
7
6
4
—
O
OCOO
Cr 65,5 SmI 74,5 SmC 118,5 SmA 135 N 137 Iso23
Cr 101,5 SmC 165,5 SmA 167 N 171,5 Iso24
Cr 82,7 (SmG 68) SmC 127,2 N 162,1 Iso
ꢀ
atmosphere, and cooled to ꢁ78 C, a sec-butyllithium solution
(77 ml 1.3 M, 0.1 mol) was added dropwise. The temperature
was maintained below ꢁ70 ꢀC and stirring was continued for 2
h. Tripropyl borate (18.8 g, 0.1 mol) was added dropwise and the
temperature was maintained below ꢁ70 ꢀC. The mixture was
then allowed to heat up to room temperature. Tetrahydrofuran
was distilled off using a vacuum evaporator. The residue was
acidied with a 10% solution of hydrochloric acid and the
5
5
5
2
—
OCOO
Cr 60 N 120 Iso10
Cr 73,4 N 171
Preparation of phenyl and biphenyl-4-yl boronic acids
resulting propanol was evaporated. The product was ltered off The procedure is given using the example of 4-chlorophenyl
and washed with hexane. Yield 82% (19 g).
boronic acid (compound 50).
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Paper
A piece of iodine crystal was added to a ask containing 01.03.01-14-106/08 “New Photonic Materials and their
magnesium turnings (7.29 g, 0.3 mol) under nitrogen atmosphere, Advanced Applications”.
and a solution of 4-bromo-1-chlorobenzene (57.4 g, 0.3 mol) in dry
tetrahydrofuran (300 ml) was then added dropwise, keeping the
mixture in gentle reux. The reaction mixture was stirred under
References
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below ꢁ70 ꢀC. The mixture was then allowed to heat up to room
temperature and was le overnight. Tetrahydrofuran was evapo-
rated off and the residue was acidied with 10% hydrochloric acid.
The propanol and the remaining tetrahydrofuran were evaporated.
The solid product was ltered off, washed with hexane and crys-
tallized from an ethanol–water solution. Yield 63% (29.5 g).
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ꢀ
To a stirred and cooled (0 C) mixture of 4-bromobiphenyl
(233 g, 1.0 mol) and aluminium chloride (200 g, 1.5 mol), pen-
tanoyl chloride (144.6 g, 1.2 mol) was added dropwise. The
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obtained ketone (158.5 g, 0.5 mol), hydrazine hydrate (46.4 g,
0.93 mol), potassium hydroxide (84.0 g, 1.5 mol) and diethylene
glycol were heated at 140 ꢀC for 3 h, and excess hydrazine
hydrate was distilled off until the temperature increased to
200 ꢀC. The mixture was then cooled and poured into 10%
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ꢀ
ethanol. Yield 70% (106.0 g), m.p. 95–96 C, purity 99.2%, MS
m/z 304, 302 (M+), 247, 245, 152, 24 57, 41, 29.
General method for the preparation of the nal products
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alkyl chloroformate was introduced by dropwise addition and
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Acknowledgements
The work was carried under the National Science Centre grant N 25 R. Ch. Geivandov, V. Mezhnev and T. Geivandova, Mol. Cryst.
N507 229640 and the European Union Key Project POIG
Liq. Cryst., 2011, 542, 106.
900 | J. Mater. Chem. C, 2014, 2, 891–900
This journal is © The Royal Society of Chemistry 2014