Styrene-containing mesogens. Part 1: Photopolymerisable nematic liquid crystals

Article abstract of DOI:10.1039/b203940k

Several members of a novel series of styrene-containing liquid crystal monomers, based on the cyanobiphenyl mesogenic group, possess thermally stable nematic phases. These materials display a large odd-even effect, relating to the length of the flexible spacer between the styrene and cyanobiphenyl units, which is very similar to previously described liquid crystal 'dimers' composed of two cyanobiphenyl units. It is shown that styrene (i.e. 4-vinylphenoxy) is an excellent terminal group for cyanobiphenyl mesogens as compared to a number of other phenyloxy groups. In addition, a compatible bifunctional mesogenic crosslinker is described. Photopolymerisation of an aligned film of a low-melting eutectic mixture derived from these compounds is achieved using cationic initiation in aerobic conditions.

Full text of DOI:10.1039/b203940k

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Styrene-containing mesogens. Part 1: photopolymerisable nematic
liquid crystals
Anthony Cook,a Samer Badriya,a Simon Greenfieldb and Neil B. McKeown*a
aDepartment of Chemistry, University of Manchester, Manchester, UK M13 9PL.
Tel: 0161 275 4710; Fax: 0161 275 4958; E-mail: neil.mckeown@man.ac.uk
bMerck Speciality Chemicals Ltd., NB-SC, UK, Chilworth Science Park, University
Parkway, Chilworth, Southampton, Hampshire, UK SO16 7QD
Received 23rd April 2002, Accepted 11th June 2002
First published as an Advance Article on the web 31st July 2002
Several members of a novel series of styrene-containing liquid crystal monomers, based on the cyanobiphenyl
mesogenic group, possess thermally stable nematic phases. These materials display a large odd–even effect,
relating to the length of the flexible spacer between the styrene and cyanobiphenyl units, which is very similar
to previously described liquid crystal ‘dimers’ composed of two cyanobiphenyl units. It is shown that styrene
(i.e. 4-vinylphenoxy) is an excellent terminal group for cyanobiphenyl mesogens as compared to a number of
other phenyloxy groups. In addition, a compatible bifunctional mesogenic crosslinker is described.
Photopolymerisation of an aligned film of a low-melting eutectic mixture derived from these compounds is
achieved using cationic initiation in aerobic conditions.
Introduction
Results and discussions
The in-situ photopolymerisation of acrylate-containing meso-
gens is an excellent method of freezing the partial order of a
liquid crystal (LC) into the solid phase.1–4 Typically, a mixture
containing a monofunctional and a bifunctional LC monomer,
together with a photoinitiator, is fabricated into a thin film and
treated to give the desired LC phase and molecular orientation.
Illumination by UV light initiates free-radical polymerisation
forming a robust and thermally stable network within which
the arrangement of the mesogenic units is retained. This tech-
nique is used for the production of films with bespoke optical
properties; for example, the incorporation of dichroic dyes
into the polymer network can produce polarising filters.4
Similarly, coloured films can be derived from the selective
reflection of light from a ‘frozen’ chiral nematic (cholesteric)
phase.3 Although LC acrylate derivatives are highly successful
monomers for photopolymerisation,5 it is expected that other
reactive polymerisable groups would help to broaden the utility
of the technique and solve a number of practical problems.
Styrene derivatives, in common with vinyl ether6,7 and epoxide8
LC monomers, offer the possibility of polymerisation using
cationic photoinitiators that would be compatible with the
presence of oxygen. However, only a few examples of styrene-
containing LC monomers have been described, to date. These
display only a very narrow thermal range of LC phase stability
or a monotropic phase (i.e. a LC phase that is observable only
below the melting point of the compound during supercool-
ing).9–11 This paper introduces a series of styrene monomers 1
which contain cyanobiphenyl, one of the simplest and most
ubiquitous of all mesogenic units. These materials displays
only a nematic liquid crystal phase, relatively high clearing
temperatures and a large odd–even effect (relating to the length
of the flexible spacer between the styrene and cyanobiphenyl
units). It is shown that the compatibility of styrene (4-vinyl-
phenoxy) as a terminal group for cyanobiphenyl mesogens is
excellent relative to a number of other phenyloxy groups. In
addition, a compatible bifunctional LC styrene that allows the
formulation of suitable mixtures for successful in-situ photo-
polymerisation is described.
Synthesis
Two synthetic routes (Schemes 1 and 2) were found bo be
convenient for the synthesis of series 1. Hydrolysis of the com-
mercially available 4-acetoxystyrene yields 4-hydroxystyrene
that, despite its reputation for instability, can be stored indefi-
nitely at 215 uC as a solution in diethyl ether. This compound
reacts with the appropriate v-bromo-a-hydroxyalkane to give
the alcohol intermediate 2. Tosylation of 2 gives 3 from which
the styrenes 1 (n ~ 5–8, 11) were prepared by reaction with
4’-hydroxy-4-cyanobiphenyl as outlined in Scheme 1.12 Alter-
natively, 4’-hydroxy-4-cyanobiphenyl was reacted with a suit-
able v,a-dibromoalkane to give intermediate 4 from which 1
(n ~ 4, 9, 10) were prepared by reaction with 4-hydroxystyrene
as shown in Scheme 2. Generally, both routes are equally
suitable for the preparation of members of series 1 as they give
comparable overall yields in the range 30–60%. However, only
the route depicted in Scheme 2 is suitable for the preparation of
1 (n ~ 4) due to the non-availability of 4-bromobutanol and
the tendency of 4-chlorobutanol to form THF rather than 2
(n ~ 4) under the basic reaction conditions encountered in
Scheme 1. Both synthetic routes to series 1 exploit the stability
of the styrene residue towards mildly basic reaction conditions.
They proved to be of greater convenience than the more
cautious strategy that uses a Wittig reaction to form the styrene
unit in the final step of the scheme.9 However, this latter
method (Scheme 3), was used in initial work concerning the
preparation of styrenes 5 (n ~ 6, 11) and 6 (n ~ 6, 11) via
intermediates 7, 8 and 9. These styrene derivatives did not
prove to be mesogenic. The bifunctional styrenes 12 and 13 are
derived from tosylate 3 (n ~ 11), via 10 and 11, respectively, as
outlined in Scheme 1.
The styrene-containing compounds appear indefinitely
stable towards polymerisation as solids and can be stored in
ambient conditions without the need for stabilisers. However,
polymerisation of 1 (n ~ 4–11), 5 and 6 to give polymers 14
(n ~ 4–11), 15 and 16, respectively, was achieved readily by free
radical initiation using AIBN in THF at 65 uC. Cyanobiphe-
nyls 19–25 were prepared from 4-hydroxy-4’-cyanobiphenyl
DOI: 10.1039/b203940k
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This journal is # The Royal Society of Chemistry 2002
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Scheme 1 Reagents and conditions: i, v-bromo-a-hydroxyalkane, EtOH, NaOH, reflux; ii, TsCl, py, 0 uC; iii, 4’-hydroxy-4-cyanobiphenyl, anhy-
drous K2CO3, DMF, 80 uC; iv, hydroquinone, EtOH, NaOH, reflux; v, terephthaloyl chloride, py, dimethoxyethane, reflux; vi, AIBN, THF, 65 uC.
Thermal behaviour
Series 1 was examined using polarising optical microscopy
and differential thermal calorimetry (DSC) and the results are
given in Fig. 1 and Table 1. All of the compounds exhibit the
Schlieren optical texture and a small enthalpy of transition
from LC to isotropic liquid (0.5–5 kJ M21) both of which are
characteristic of the nematic phase. For 1 (n ~ 5 and 10) the
nematic phase is monotropic. A comparison of the thermal
Scheme 2 Reagents and conditions: i, excess a,v-dibromoalkane,
anhydrous K2CO3, MEK, 80 uC; ii, 4-hydroxystyrene, anhydrous
K2CO3, MEK, 80 uC; iii, v-bromo-a-hydroxyalkane, EtOH, NaOH,
reflux; iv, TsCl, py, 0 uC; v, 4-XC6H4OH, anhydrous K2CO3, MEK,
80 uC.
via intermediates 17 and 18 using ether forming reactions as
outlined in Scheme 2. Spectroscopic analysis confirmed the
structure of each compound and all mesogens provided a
satisfactory elemental analysis.
Fig. 1 A diagramatic representation of the thermal behaviour of series
1. For each compound the shaded bar represents the crystal phase and
r represents the nematic to isotropic (clearing) transition temperature.
Compounds 1 (n ~ 5 and 10) show monotropic nematic phases which
are observable only on supercooling below the crystal to isotropic
liquid transition.
Table 1 Temperature (DH/kJ mol21, DS/J K21 mol21) of phase
transitions of series 1 and bifunctional mesogens 12 and 13
Crystal to nematic
(K–N)/uC
Nematic to isotropic
(N–I)/uC
1 (n ~ 4)
1 (n ~ 5)a
1 (n ~ 6)
1 (n ~ 7)
1 (n ~ 8)
1 (n ~ 9)
1 (n ~ 10)a
1 (n ~ 11)
12
146.5 (46.8, 111)
85.6 (54.2, 150)
109.4 (46.4, 121)
77.0 (63.1, 180)
100.5 (41.8, 111)
82.5 (26.4, 74)
112.1 (32.5, 83)
75.8 (67.7, 194)
105.0 (74.2, 196)
73.0 (71.7, 200)
155.0 (2.1, 5)
76.7 (0.7, 2)
132.7 (3.5, 8)
91.0 (1.1, 3)
119.1 (2.3, 6)
92.8 (0.4, 1)
111.9 (3.5, 9)
95.7 (1.2, 3)
145.1 (0.4, 1)
108.3 (1.9, 5)
Scheme 3 Reagents and conditions: i, TsCl, py, 0 uC; ii, v, 4-hydroxy-4’-
alkylbiphenyl, anhydrous K2CO3, DMF, 80 uC; iii, methyltriphenyl-
phosphonium bromide, t-BuOK, THF; iv, AIBN, THF, 65 uC.
13
aCompounds 1 (n ~ 5 and 10) exhibit a monotropic nematic phase.
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behaviour of series 1 with that of the much studied 4’-alkoxy-4-
cyanobiphenyl homologous series13 reveals that the terminal
4-vinylphenoxy (styrene) group results in both higher melting
and clearing transition temperatures. It addition, the styrene
group prevents formation of the smectic A mesophase which
is prevalent in the 4’-alkoxy-4-cyanobiphenyl series for mem-
bers with long alkyl chains (wheptyloxy). Another interesting
feature of series 1 is the much higher transition temperatures
for those compounds which possess an even number of atoms
in the flexible linkage between the styrene and cyanobiphenyl
units (n ~ 5, 7, 9, 11). The odd–even effect is associated with
the lowest energy (i.e. all-anti) conformation of the alkyl
spacer. Thus, a spacer containing an even number of atoms
encourages the two rigid aromatic units to lie parallel to one
another thereby enhancing the rod-like character of the mole-
cule and raising the transition temperatures. An odd–even
effect is also apparent for the entropy change associated with
the nematic to isotropic transition. Members of series 1
containing a spacer with an even number of atoms (n ~ 4, 6, 8,
regions, consistent with Smectic A. Series 14 have been
prepared previously by grafting the mesogenic side-chains
onto poly(4-hydroxystyrene).17 The transition temperatures
obtained in both studies are similar, although the absence of
liquid crystallinity for 14 (n ~ 4 and 5) is anomalous.
Photopolymerisation studies
Photopolymerisation is normally carried out at, or just above,
room temperature. In LC technology it is usual for a mixture
of compounds to be formulated in order to achieve desired
properties such as a reduction in crystal to liquid crystal
transition temperature. It was found that a mixture containing
an equal amount of the lower melting members of series 1 (n ~
5, 7, 11) displays a eutectic melting point of 42 uC with a
clearing temperature of 88 uC. On cooling, the nematic phase
is retained at room temperature for an extended period before
crystallisation and, therefore, this mixture is particularly
attractive for in-situ photopolymerisation. Bifunctional styrene
13 has a solid to nematic transition temperature below, and a
clearing temperature above, that of the three components of
the eutectic mixture. Thus, it was anticipated that this material
would be a suitable cross-linking agent for network formation
for this mixture. Indeed up to 30%, by mass, of 13 does not
have a significant effect on the transition temperature of the
eutectic mixture.
For the photopolymerisation experiments, films were
deposited onto a glass substrate coated with rubbed polyimide
by spin-coating a 10% (w/w) solution of the eutectic mixture
containing cross-linker 13 in toluene–xylene–isopropyl alcohol
(4 : 2 : 1) at 3000 rpm. These solutions also contained a cationic
photoinitiator system composed of 1%, by mass, of diphenyl-
iodonium hexaflourophosphate and a similar amount of pheno-
thiazine photosensitiser. Photopolymerisation was achieved at
65 uC in air using a filtered UV light source (Blak-Ray B100 AP)
with a narrow emission band at 360 nm. For films containing
30% (w/w) of cross-linker 13, extraction of the resulting film
with THF gave only residual (v1%) amounts of unreacted
monomer. Films with 10% (w/w) cross-linker 13 gave up to
15% unreacted monomer. The resulting films were indistin-
guishable in appearance from the uncured oriented film using
polarising microscopy and exhibited excellent mechanical
resilience. Similar results were obtained using free radical
photoinitiator (Irgacure 651) under a nitrogen atmosphere.
This work demonstrates that cyanobiphenyl-based styrene
monomers provide a versatile alternative to acrylate liquid
crystals for in-situ photopolymerisation.
10) demonstrate a larger entropy change (5–9 J K21 mol21
)
than that (1–3 J K21 mol21) shown by compounds with an odd
number of atoms in the spacer (n ~ 5, 7, 9, 11). These ‘odd–
even’ effects and the absence of a smectic phase is highly remi-
niscent of the thermal behaviour of compounds which possess
two mesogenic groups linked by a flexible spacer (termed
LC ‘dimers’) such as the a,v-bis(4’-cyano-4-biphenyloxy)-
alkanes.14,15
The bifunctional styrenes 12 and 13 display the nematic
phase over a large thermal range (w30 uC). The two lateral
methyl substituents of 13 suppresses the transition tempera-
tures by y30 uC relative to 12 (Table 1). The benefit of small
lateral substituents for lowering the transition temperatures of
bifunctional cross-linking mesogens has been noted for similar
acrylate derivatives.16
The synthesis of compounds 19–25 (Scheme 2) allowed a
non-systematic assessment of the beneficial effect of the vinyl
group found in series 1. Compounds 19–25 have the same
spacer as 1 (n ~ 11) but different substituents (X ~ Cl, Br, CN,
OMe, Et, Pr, Bu) on the 4-position of the phenoxy group. A
comparison of the thermal behaviour of 1 (n ~ 11) with those
of 19–25, shows that the vinyl group is the only terminal group
compatible with a thermally stable (i.e. entiomeric) nematic
phase (Fig. 2).
The polymers 14 (n ~ 6–11), 15 and 16, all display a liquid
crystalline phase with the classic ‘sandy’ texture which is often
encountered for side-chain liquid crystals. Annealing over
several hours gave a fine-grained texture, with homeotropic
Experimental
High resolution (500 MHz) 1H NMR spectra were recorded
using a Varian Unity 500 spectrometer. IR spectra were
recorded on a ATI Mattson Genesis Series FTIR (KBr/
Germanium beam splitter). Elemental analyses were obtained
using a Carlo Erba Instruments CHNS-O EA 108 Elemental
Analyser. Routine low-resolution chemical ionisation (CI)
mass spectra were obtained using a Fisons Instruments Trio
2000. All solvents were dried and purified as described in ref.
18. Silica gel (60 Merck 9385) was used in the separation and
purification of compounds by column chromatography. All
materials were placed under vacuum for 18 hours as the final
step of purification. The intermediate, 11-(4’-cyanobiphenyloxy)-
undecan-1-ol, (Scheme 3) was made by the reaction of
4-cyano-4’-hydroxybiphenyl, kindly supplied by Merck, with
11-bromoundecan-1-ol.19,20 Molecular mass was determined
using gel permeation chromatography (GPC) using 3x PL Gel-
Mixed B analytical columns (Polymer Laboratories) calibrated
against polystyrene standards and using THF as eluent. Differ-
ential scanning calorimetry measurements were made on a
Seiko DSC 220C machine and calibrated using an indium
Fig. 2 A diagramatic comparison of the thermal behaviour of 1 (n ~
11) and compounds 19–25. For each compound the shaded bar
represents the crystal phase and r represents the nematic to isotropic
(clearing) transition temperature. For X ~ Cl, OMe, Et, Pr and Bu
only monotropic nematic phases are observable on supercooling below
the crystal to isotropic liquid transition. For X ~ CN and Br no
mesophase was observed on heating or cooling.
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standard. Optical microscopy observations were made on a
Nikon Optiphot-2 microscope with a Mettler FP80 HT Hot
Stage.
and water (400 ml). The organic layer was dried (MgSO4)
and the solvent removed under reduced pressure. The crude
product was purified by column chromatography (eluent:
toluene) to give 3 as a viscous colourless oil (63.42 g, 81%)
(Found: C, 69.88; H, 8.47; S, 7.25%. C26H36O4S requires C,
70.25; H, 8.15; S, 70.25%); dH (CDCl3, 300 MHz, 25 uC) 1.1–1.5
(14H, m), 1.68–1.73 (4H, m), 2.44 (3H, s), 3.95–4.00 (4H, m),
5.14 (1H, d, J 11), 5.60 (1H, d, J 18), 6.67 (1H, dd, J 11,18), 6.85
(2H, d, J 9), 7.35 (2H, d, J 9), 7.65 (2H, d, J 9), 7.83 (2H, d, J 9);
m/z (CI) 462 (M1 1 NH41), 445 (M1).
4-(11-Hydroxyundecyloxy)styrene 2 (n ~ 11)
Following the method of Andersson et al.,10 4-acetoxystyrene
(35.47 g, 218.9 mmol) was added to a stirred solution of KOH
(35.47 g, 633 mmol) in EtOH (300 ml). After 1 h, sodium
ethoxide (16.24 g, 238.8 mmol) was added and the mixture was
heated to reflux for 0.5 h. A solution of 11-bromo-1-undecanol
(54.24 g, 218.9 mmol) in EtOH (300 ml) was added and the
solution was heated at reflux for 20 h. Removal of the solvent
under reduced pressure gave a viscous oil to which was added
aq. NaHCO3 (10% w/w, 600 ml). The product was extracted
using CH2Cl2 (3 6 100 ml), washed with aq. NaOH (1.0 M,
2 6 400 ml) and water (600 ml). The organic layer was dried
(MgSO4) and the solvent removed under reduced pressure. The
crude product was recrystallised from hexane to give 2 (n ~ 11)
as white crystals (56.45 g, 78%): mp 73 uC (Found: C, 78.05; H,
10.4%. C19H30O2 requires C, 78.55; H, 10.4%); dH (CDCl3,
300 MHz, 25 uC) 1.2–1.9 (18H, m), 3.63 (2H, t, J 7), 4.00 (2H, t,
J 7), 5.18 (1H, d, J 11), 5.63 (1H, d, J 18), 6.78 (1H, dd, J 11,18),
6.88 (2H, d, J 9), 7.38 (2H, d, J 9); m/z (CI) 308 (M1 1 NH41),
268 (M1).
The following compounds were prepared using a similar
procedure.
4-[5-(p-Tosyloxy)pentyloxy]styrene 3 (n ~ 5)
The crude product (10.03 g, 55%) was obtained from 2 (n ~ 5)
as a viscous colourless oil which was used without further
purification: dH (CDCl3, 300 MHz, 25 uC) 1.2–2.0 (6H, m), 2.44
(3H, s), 3.95–4.00 (4H, m), 5.14 (1H, d, J 11), 5.60 (1H, d, J 18),
6.67 (1H, dd, J 11,18), 6.85 (2H, d, J 9), 7.35 (2H, d, J 9), 7.65
(2H, d, J 9), 7.83 (2H, d, J 9); m/z (CI) 378 (M1 1 NH41), 361
(M1).
4-[6-(p-Tosyloxy)hexyloxy]styrene 3 (n ~ 6)
The crude product (6.35 g, 60%) was obtained from 2 (n ~ 6)
as a viscous colourless oil which was used without further
purification: dH (CDCl3, 300 MHz, 25 uC) 1.36–1.43 (4H, m),
1.68–1.73 (4H, m), 2.44 (3H, s), 3.93 (2H, t, J 7), 4.08 (2H, t,
J 7), 5.18 (1H, d, J 11), 5.63 (1H, d, J 18), 6.67 (1H, dd, J 11,18),
6.85 (2H, d, J 9), 7.25 (2H, d, J 9), 7.65 (2H, d, J 9), 7.83 (2H, d,
J 9); m/z (CI) 392 (M1 1 NH41), 375 (M1).
The following compounds were prepared using a similar
procedure.
4-(5-Hydroxypentyloxy)styrene 2 (n ~ 5)
The crude product (12.24 g, 71%) was obtained as a viscous
colourless oil which was used without further purification: dH
(CDCl3, 300 MHz, 25 uC) 1.5–1.9 (6H, m), 3.70 (2H, t, J 7),
4.00 (2H, t, J 7), 5.18 (1H, d, J 11), 5.63 (1H, d, J 18), 6.70 (1H,
dd, J 11,18), 6.85 (2H, d, J 9), 7.38 (2H, d, J 9); m/z (CI) 224
(M1 1 NH41), 206 (M1).
4-[7-(p-Tosyloxy)heptyloxy]styrene 3 (n ~ 7)
The product (6.93 g, 89%) was obtained from 2 (n ~ 7) as a
viscous colourless oil which was used without further puri-
fication: dH (CDCl3, 300 MHz, 25 uC) 1.36–1.43 (6H, m), 1.68–
1.73 (4H, m), 2.48 (3H, s), 3.96 (2H, t, J 7), 4.08 (2H, t, J 7),
5.18 (1H, d, J 11), 5.63 (1H, d, J 18), 6.67 (1H, dd, J 11,18), 6.85
(2H, d, J 9), 7.25 (2H, d, J 9), 7.65 (2H, d, J 9), 7.83 (2H, d, J 9);
m/z (CI) 392 (M1 1 NH41), 375 (M1).
4-(6-Hydroxyhexyloxy)styrene 2 (n ~ 6)
The crude product (7.52 g, 65%) was obtained as a viscous
colourless oil which was used without further purification: dH
(CDCl3, 300 MHz, 25 uC) 1.3–1.9 (8H, m), 3.70 (2H, t, J 7),
4.00 (2H, t, J 7), 5.18 (1H, d, J 11), 5.63 (1H, d, J 18), 6.63 (1H,
dd, J 11,18), 6.87 (2H, d, J 9), 7.39 (2H, d, J 9); m/z (CI) 238
(M1 1 NH41), 220 (M1).
4-[8-(p-Tosyloxy)octyloxy]styrene 3 (n ~ 8)
The product (6.93 g, 89%) was obtained from 2 (n ~ 8) as a
viscous colourless oil which was used without further puri-
fication: dH (CDCl3, 300 MHz, 25 uC) 1.15–1.90 (12H, m), 2.44
(3H, s), 3.98 (2H, t, J 7), 4.18 (2H, t, J 7), 5.18 (1H, d, J 11), 5.63
(1H, d, J 18), 6.67 (1H, dd, J 11,18), 6.88 (2H, d, J 9), 7.25 (2H,
d, J 9), 7.40 (2H, d, J 9), 7.83 (2H, d, J 9); m/z (CI) 392 (M1 1
NH41), 375 (M1).
4-(7-Hydroxyheptyloxy)styrene 2 (n ~ 7)
The product (4.30 g, 71%) was obtained as a viscous colourless
oil (Found: C, 77.20; H, 9.50%. C15H22O2 requires C, 76.90; H,
9.45%); dH (CDCl3, 300 MHz, 25 uC) 1.3–1.9 (10H, m), 3.68
(2H, t, J 7), 4.00 (2H, t, J 7), 5.18 (1H, d, J 11), 5.63 (1H, d,
J 18), 6.71 (1H, dd, J 11,18), 6.87 (2H, d, J 9), 7.39 (2H, d, J 9);
m/z (CI) 252 (M1 1 NH41), 235 (M1).
4-(6-p-Tosyloxy)hexyloxybenzaldehyde 7 (n ~ 6)
The product (14.28 g, 59%) was obtained from 6-(4-formyl-
phenoxy)hexan-1-ol as colourless crystals: mp 76 uC (MeOH)
(Found: C, 63.85; H, 6.6; S, 8.8%. C20H24O5S requires C, 63.8;
H, 6.45; S, 8.5%); dH (CDCl3, 300 MHz, 25 uC) 1.20–1.90 (8H,
m), 2.44 (3H, s), 3.98–4.08 (4H, m), 6.94 (2H, d, J 9), 7.35 (2H,
4-(8-Hydroxyoctyloxy)styrene 2 (n ~ 8)
The crude product (10.70 g, 72%) was obtained as a viscous
colourless oil which was used without further purification: dH
(CDCl3, 300 MHz, 25 uC) 1.3–1.9 (12H, m), 3.65 (2H, t, J 7),
4.00 (2H, t, J 7), 5.18 (1H, d, J 11), 5.63 (1H, d, J 18), 6.70 (1H,
dd, J 11,18), 6.85 (2H, d, J 9), 7.38 (2H, d, J 9); m/z (CI) 266
(M1 1 NH41), 249 (M1).
d, J 9), 7.81 (4H, d, J 9), 9.89 (1H, s); m/z (CI) 394 (M1
1
NH41).
4-(11-p-Tosyloxy)undecyloxybenzaldehyde 7 (n ~ 11)
4-[11-(p-Tosyloxy)undecyloxy]styrene 3 (n ~ 11)
The product (12.56 g, 57%) was obtained from 6-(4-formylphen-
oxy)undecan-1-ol as colourless crystals: mp 52 uC (hexane)
(Found: C, 67.1; H, 7.75; S, 7.1%. C25H34O5S requires C, 67.25;
H, 7.65; S, 7.2%); dH (CDCl3, 300 MHz, 25 uC) 1.10–1.90 (18H,
m), 2.44 (3H, s), 3.98–4.08 (4H, m), 6.98 (2H, d, J 9), 7.35 (2H,
A solution of 2 (n ~ 11) (47.24 g, 176 mmol) in CH2Cl2 (300 ml)
was added dropwise to a stirred solution of p-tosyl chloride
(39 g, 205 mmol) in pyridine (150 ml) and CH2Cl2 (500 ml).
Stirring was continued for 6 h after which TLC analysis
indicated the absence of the alcohol. The mixture was washed
with aq. HCl (1 M, 3 6 500 ml), aq. NaOH (2 M, 2 6 400 ml)
d, J 9), 7.81 (4H, d, J 9), 9.89 (1H, s); m/z (CI) 464 (M1
1
NH41), 447 (M1).
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4-(11-p-Tosyloxy)undecyloxy-4’-cyanobiphenyl 18
ethoxide (0.4 g, 5.8 mmol) was added and the mixture was
heated to reflux for 0.5 h. A solution of 4 (n ~ 4) (1.8 g,
5.4 mmol) in EtOH (8 ml) was added and the solution was
heated at reflux for 20 h. Removal of the solvent under reduced
pressure gave a solid residue which was dissolved in CH2Cl2
(50 ml), washed with aq. NaOH (1.0 M, 2 6 10 ml) and water
(20 ml). The organic layer was dried (MgSO4) and the solvent
removed under reduced pressure. The crude product was
recrystallised from CH2Cl2–EtOH to give 1 (n ~ 4) as white
crystals (1.52 g, 76%): thermal transitions (uC): K 146.5 N 155.0
I (Found: C, 81.23; H, 6.15; N, 3.70%. C25H23NO2 requires C,
81.25; H, 6.30; N, 3.80%); n(KBr)/cm21 2220 (CN); dH (CDCl3,
300 MHz, 25 uC) 1.9–2.1 (4H, m), 4.0–4.2 (4H, m), 5.04 (1H, d,
J 11), 5.53 (1H, d, J 18), 6.58 (1H, dd, J 11,18), 6.78 (2H, d, J 9),
6.93 (2H, d, J 9), 7.26 (2H, d, J 9), 7.44 (2H, d, J 9), 7.58 (2H, d,
J 9), 7.63 (2H, d, J 9); m/z (CI) 387 (M1 1 NH41), 369 (M1).
The following compounds were prepared using a similar
procedure.
The product (7.9 g, 65%) was obtained from 17 as colourless
crystals: mp 94 uC (EtOH) (Found: C, 71.68; H, 7.05; N, 2.59;
S, 5.76%. C31H37NO4S requires C, 71.65; H, 7.18; N, 2.70; S,
6.17%); n(thin film)/cm21 2224 (CN); dH (CDCl3, 300 MHz,
25 uC) 1.10–1.90 (18H, m), 2.46 (3H, s), 3.98–4.08 (4H, m), 7.01
(2H, d, J 9), 7.36 (2H, d, J 9), 7.55 (2H, d, J 9), 7.66 (2H, d, J 9),
7.72 (2H, d, J 9), 7.81 (2H, d, J 9); m/z (CI) 537 (M1 1 NH41),
519 (M1).
4-(4-Bromobutyloxy)-4’-cyanobiphenyl 4 (n ~ 4)
To a solution of 4-hydroxy-4’-cyanobiphenyl (5.00 g, 25.6 mmol)
and 1,4-dibromobutane (55.4 g, 256.4 mmol) in DMF (50 ml)
was added K2CO3 (7.09 g, 51.3 mmol). The reaction was
heated at 80 uC at 0.5 h. On cooling, the DMF and excess 1,4-
dibromobutane were removed under reduced pressure. Water
(50 ml) was added to the solid residue and the product was
extracted with CH2Cl2, dried (MgSO4) and evaporated to dry-
ness under reduced pressure. The product was recrystallised
from EtOH to give colourless crystals (6.90 g, 81%): thermal
transitions (uC): K 57 N 65 I (Found: C, 62,25; H, 4.95; N, 4.23;
Br, 23.6%. C17H16BrNO requires C, 62.0; H, 4.92; N, 4.25; Br,
24.0%); n(KBr)/cm21 2220 (CN); dH (CDCl3, 300 MHz, 25 uC)
2.06–2.10 (4H, m), 3.55 (2H, t, J 7), 4.09 (2H, t, J 7), 7.02 (2H,
d, J 9), 7.44 (2H, d, J 9), 7.58 (2H, d, J 9), 7.72 (2H, d, J 9); m/z
(CI) 349 (M1 1 NH41 1 2), 347 (M1 1 NH41), 331 (M1 1 2),
329 (M1).
4-[9-(4-Vinylphenyloxy)nonyloxy]-4’-cyanobiphenyl 1 (n ~ 9)
The crude product was obtained from 4 (n ~ 9) and
recrystallised from EtOH to give white crystals (1.03 g, 38%):
thermal transitions (uC): K 82.5 N 92.8 I (Found: C, 82.01; H,
7.74; N, 3.14%. C30H33NO2 requires C, 81.97; H, 7.57; N,
3.19%); n(KBr)/cm21 2225 (CN); dH (CDCl3, 300 MHz, 25 uC)
1.37–1.57 (10H, m), 1.78–1.85 (4H, m), 4.0–4.0 (4H, m), 5.16
(1H, d, J 11), 5.64 (1H, d, J 18), 6.70 (1H, dd, J 11,18), 6.89
(2H, d, J 9), 7.03 (2H, d, J 9), 7.36 (2H, d, J 9), 7.56 (2H, d, J 9),
7.67 (2H, d, J 9), 7.73 (2H, d, J 9); m/z (CI) 457 (M1 1 NH41),
439 (M1).
The following compounds were prepared using a similar
procedure.
4-(9-Bromononyloxy)-4’-cyanobiphenyl 4 (n ~ 9)
4-[10-(4-Vinylphenyloxy)decyloxy]-4’-cyanobiphenyl 1 (n ~ 10)
The product was obtained using 1,9-dibromononane and
recrystallised from EtOH to give colourless crystals (3.06 g,
87.8%): thermal transitions (uC); K 68.3 (N 65.0) I (Found: C,
65.98; H, 6.67; N, 3.55; Br, 20.22%. C22H26BrNO requires C,
66.27; H, 6.52; N, 3.51; Br, 20.05%); n(thin film)/cm21 2222
(CN); dH (CDCl3, 300 MHz, 25 uC) 1.33–1.53 (10H, br m), 1.88
(4H, m), 3.45 (2H, t, J 7), 4.05 (2H, t, J 7), 7.03 (2H, d, J 9), 7.58
(2H, d, J 9), 7.68 (2H, d, J 9), 7.74 (2H, d, J 9); m/z (CI) 419
(M1 1 NH411 2), 417 (M1 1 NH21), 401 (M1 1 2), 399
(M1).
The crude product was obtained from 4 (n ~ 10) recrystallised
from EtOH to give white crystals (0.86 g, 34%): thermal tran-
sitions (uC): K 112.1 (N 111.9) I (Found: C, 82.28; H, 7.96; N,
3.07%. C31H35NO2 requires C, 82.08; H, 7.78; N, 3.09%);
n(KBr)/cm21 2226 (CN); dH (CDCl3, 300 MHz, 25 uC) 1.37–
1.57 (12H, m), 1.78–1.89 (4H, m), 4.0–4.1 (4H, m), 5.15 (1H, d,
J 11), 5.64 (1H, d, J 18), 6.70 (1H, dd, J 11,18), 6.89 (2H, d, J 9),
7.03 (2H, d, J 9), 7.37 (2H, d, J 9), 7.56 (2H, d, J 9), 7.67 (2H, d,
J 9), 7.73 (2H, d, J 9); m/z (CI) 471 (M1 1 NH41), 453 (M1).
4-[5-(4-Vinylphenyloxy)pentyloxy]-4’-cyanobiphenyl 1 (n ~ 5)
4-(10-Bromodecyloxy)-4’-cyanobiphenyl 4 (n ~ 10)
To a solution of 4-hydroxy-4’-cyanobiphenyl (1.7 g, 8.7 mmol)
and 3 (n ~ 5) (2.76 g, 7.7 mmol) in DMF (50 ml) was added
K2CO3 (2.8 g, 20 mmol). The reaction was heated at 80 uC
for 0.5 h. On cooling, the DMF was removed under reduced
pressure. Water (50 ml) was added to the solid residue and
the product was extracted with CH2Cl2 (2 6 50 ml), dried
(MgSO4) and evaporated to dryness under reduced pressure.
The product was purified by column chromatography (eluent:
toluene) and recrystallisation from EtOH to give colourless
crystals (2.21 g, 76%): thermal transitions (uC): K 85.6 (N 76.7)
I (Found: C, 81.62; H, 6.70; N, 3.70%. C26H25O2N requires C,
81.40; H, 6.60; N, 3.65%); n(KBr)/cm21 2220 (CN); dH (CDCl3,
300 MHz, 25 uC) 1.7–2.1 (6H, m), 4.0–4.2 (4H, m), 5.04 (1H, d,
J 11), 5.53 (1H, d, J 18), 6.58 (1H, dd, J 11,18), 6.78 (2H, d, J 9),
6.93 (2H, d, J 9), 7.26 (2H, d, J 9), 7.44 (2H, d, J 9), 7.58 (2H, d,
J 9), 7.63 (2H, d, J 9); m/z (CI) 401 (M1 1 NH41), 383 (M1).
The following compounds were prepared using a similar
procedure.
The product was obtained using 1,10-dibromodecane and
recrystallised from EtOH to give colourless crystals (2.57 g,
87.9%): thermal transitions (uC): K 63.3 (N 64.9) I (Found:
66.80; H, 6.76; N, 3.34; Br, 19.41%. C23H28BrNO requires C,
66.67; H, 6.81; N, 3.38; Br, 19.28%); n(KBr)/cm21 2220 (CN);
dH (CDCl3, 300 MHz, 25 uC) 1.30–1.56 (12H, br m), 1.88 (4H,
m), 3.45 (2H, t, J 7), 4.02 (2H, t, J 7), 7.0 (2H, d, J 9), 7.44 (2H,
d, J 9), 7.56 (2H, d, J 9), 7.70 (2H, d, J 9); m/z (CI) 433 (M1 1
NH411 2), 431 (M1 1 NH41), 415 (M1 1 2), 413 (M1).
4-(11-Hydroxyundecyloxy)-4’-cyanobiphenyl 17
The product was obtained using 11-bromoundecan-1-ol and
recrystallised from EtOH to give colourless crystals (9.07 g,
82%): thermal transitions (uC): K 89.8 N 92.0 I (Found: 79.16;
H, 9.00; N, 3.86%. C24H31NO2 requires C, 78.89; H, 8.55; N,
3.83%); dH (CDCl3, 300 MHz, 25 uC) 1.20–1.62 (16H, br m),
1.78–1.85 (4H, m), 3.66 (2H, t, J 6), 4.02 (2H, t, J 6), 7.02 (2H,
d, J 9), 7.55 (2H, d, J 9), 7.67 (2H, d, J 9), 7.73 (2H, d, J 9); m/z
(CI) 383 (M1 1 NH41), 365 (M1).
4-[6-(4-Vinylphenyloxy)hexyloxy]-4’-cyanobiphenyl 1 (n ~ 6)
The product was obtained from 3 (n ~ 6) and purified by
column chromatography (eluent: toluene) and recrystallisation
from EtOH to give colourless crystals (2.82 g, 68%): thermal
transitions (uC): K 109.4 N 132.7 I (Found: C, 81.65; H, 6.75;
4-[4-(4-Vinylphenyloxy)butyloxy]-4’-cyanobiphenyl 1 (n ~ 4)
To a solution of KOH (1 g, 18 mmol) in EtOH (8 ml) was
added 4-acetoxystyrene (0.8 g, 5.4 mmol). After 1 h, sodium
J. Mater. Chem., 2002, 12, 2675–2683
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N, 3.50%. C27H27NO2 requires C, 81.55; H, 6.85; N, 3.55%);
n(KBr)/cm21 2220 (CN); dH (CDCl3, 300 MHz, 25 uC) 1.6–2.1
(8H, m), 4.0–4.2 (4H, m), 5.04 (1H, d, J 11), 5.53 (1H, d, J 18),
6.58 (1H, dd, J 11,18), 6.78 (2H, d, J 9), 6.93 (2H, d, J 9), 7.26
(2H, d, J 9), 7.44 (2H, d, J 9), 7.58 (2H, d, J 9), 7.63 (2H, d, J 9);
m/z (CI) 417 (M1 1 NH41), 398 (M1).
4-[11-(4-Formylphenyloxy)hexyloxy]-4’-n-propylbiphenyl 8 (n ~ 6)
The product was obtained from 7 (n ~ 6) and 4-hydroxy-4’-n-
propylbiphenyl and was used in the next step without further
purification (5.42 g, 81%): dH (CDCl3, 300 MHz, 25 uC) 0.93
(3H, t, J 7), 1.4–2.1 (10H, m), 2.62 (2H, t, J 7), 4.0–4.2 (4H, m),
6.93 (4H, m), 7.21 (2H, d, J 9), 7.48 (4H, m), 7.8 (2H, d, J 9),
9.89 (1H, s); m/z (CI) 434 (M1 1 NH41), 417 (M1).
4-[7-(4-Vinylphenyloxy)heptyloxy]-4’-cyanobiphenyl 1 (n ~ 7)
4-[11-(4-Formylphenyloxy)undecyloxy]-4’-n-propylbiphenyl 8
(n ~ 11)
The product was obtained from 3 (n ~ 7) and purified by
column chromatography (eluent: toluene) and recrystallisation
from EtOH to give colourless crystals (5.54 g, 75%): thermal
transitions (uC): K 77.0 N 91.0 I (Found: C, 81.2; H, 6.95; N,
3.25%. C28H29NO2 requires C, 81.70; H, 7.1; N, 3.40%);
n(KBr)/cm21 2220 (CN); dH (CDCl3, 300 MHz, 25 uC) 1.4–2.1
(10H, m), 4.0–4.2 (4H, m), 5.04 (1H, d, J 11), 5.53 (1H, d, J 18),
6.58 (1H, dd, J 11,18), 6.78 (2H, d, J 9), 6.93 (2H, d, J 9), 7.26
(2H, d, J 9), 7.44 (2H, d, J 9), 7.58 (2H, d, J 9), 7.63 (2H, d, J 9);
m/z (CI) 429 (M1 1 NH41), 412 (M1).
The product was obtained from 7 (n ~ 11) and 4-hydroxy-4’-n-
propylbiphenyl and was used in the next step without further
purification (6.31 g, 84%): dH (CDCl3, 300 MHz, 25 uC) 0.93
(3H, t, J 7), 1.1–2.1 (20H, m), 2.62 (2H, t, J 7), 4.0–4.2 (4H, m),
6.93 (4H, m), 7.21 (2H, d, J 9), 7.48 (4H, m), 7.8 (2H, d, J 9),
9.89 (1H, s); m/z (CI) 504 (M1 1 NH41), 487 (M1).
4-[6-(4-Formylphenyloxy)hexyloxy]-4’-((S)-(1)-2-methylbutyl)-
biphenyl 9 (n ~ 6)
4-[8-(4-Vinylphenyloxy)octyloxy]-4’-cyanobiphenyl 1 (n ~ 8)
The product was obtained from 7 (n ~ 6) and (S)-(1)-4-
hydroxy-4’-(2-methylbutyl)biphenyl and was purified by recry-
stallisation from EtOH to give colourless crystals (1.93 g, 85%):
mp 89 uC (Found: C, 81.05; H, 8.45%. C30H36O3 requires C,
81.05; H, 8.5); dH (CDCl3, 300 MHz, 25 uC) 0.90–0.93 (6H, m),
1.1–2.09 (11H, m), 2.39 (1H, q, J 7), 2.67 (1H, q, J 7), 4.0–4.2
(4H, m), 6.96 (4H, m), 7.16 (2H, d, J 9), 7.48 (4H, m), 7.81 (2H,
d, J 9), 9.89 (1H, s); m/z (CI) 462 (M1 1 NH41), 445 (M1).
The product was obtained from 3 (n ~ 8) and purified by
column chromatography (eluent: toluene) and recrystallisation
from EtOH to give colourless crystals (1.64 g, 48%): thermal
transitions (uC): K 100.5 N 119.1 I (Found: C, 81.8; H, 7.45; N,
3.40%. C29H31O2N requires C, 81.85; H, 7.35; N, 3.3%);
n(KBr)/cm21 2220 (CN); dH (CDCl3, 300 MHz, 25 uC) 1.3–2.1
(12H, m), 4.0–4.2 (4H, m), 5.04 (1H, d, J 11), 5.53 (1H, d, J 18),
6.58 (1H, dd, J 11,18), 6.78 (2H, d, J 9), 6.93 (2H, d, J 9), 7.26
(2H, d, J 9), 7.44 (2H, d, J 9), 7.58 (2H, d, J 9), 7.63 (2H, d, J 9);
m/z (CI) 443 (M1 1 NH41), 426 (M1).
4-[11-(4-Formylphenyloxy)undecyloxy]-4’-((S)-(1)-2-methylbutyl)-
biphenyl 9 (n ~ 11)
The product was obtained from 7 (n ~ 11) and (S)-(1)-4-
hydroxy-4’-(2-methylbutyl)biphenyl and was purified by recry-
stallisation from EtOH to give colourless crystals (1.86 g, 83%):
mp 53 uC (Found: C, 80.95; H, 8.95%. C35H46O3 requires C,
81.65; H, 9.0); dH (CDCl3, 300 MHz, 25 uC) 0.90–0.93 (6H, m),
1.1–2.09 (21H, m), 2.39 (1H, q, J 7), 2.67 (1H, q, J 7), 4.0–4.2
(4H, m), 6.96 (4H, m), 7.16 (2H, d, J 9), 7.48 (4H, m), 7.84 (2H,
d, J 9), 9.89 (1H, s); m/z (CI) 532 (M1 1 NH41), 515 (M1).
4-[11-(4-Vinylphenyloxy)undecyloxy]-4’-cyanobiphenyl 1 (n ~ 11)
The product was obtained from 3 (n ~ 11) and purified by
column chromatography (eluent: toluene) and recrystallisation
from EtOH to give colourless crystals (3.35 g, 77%): thermal
transitions (uC): K 75.8 N 95.7 I (Found: C, 82.3; H, 8.15; N,
3.2%. C32H37NO2 requires C, 82.2; H, 8.0; N, 3.0%); n(KBr)/
cm21 2220 (CN); dH (CDCl3, 300 MHz, 25 uC) 1.1–2.1 (18H,
m), 4.0–4.2 (4H, m), 5.04 (1H, d, J 11), 5.53 (1H, d, J 18), 6.58
(1H, dd, J 11,18), 6.78 (2H, d, J 9), 6.93 (2H, d, J 9), 7.26 (2H,
d, J 9), 7.44 (2H, d, J 9), 7.58 (2H, d, J 9), 7.63 (2H, d, J 9); m/z
(CI) 485 (M1 1 NH41), 468 (M1).
4-[11-(4-Chlorophenyloxy)undecyloxy]-4’-cyanobiphenyl 19
The product was obtained from 18 and 4-chlorophenol and
purified by recrystallisation from EtOH to give colourless
crystals (0.76 g, 54%): thermal transitions (uC): K 78.8 (N 75.3)
I (Found: C, 76.13; H, 7.12; N, 3.13; Cl, 7.58%. C30H34ClNO2
requires C, 75.69; H, 7.20; N, 2.94; Cl, 7.45%); n(thin film)/
cm21 2222 (CN); dH (CDCl3, 300 MHz, 25 uC) 1.20–1.60 (14H,
m), 1.74–1.86 (4H, m), 3.94 (2H, d, J 7), 4.03 (2H, d, J 7), 6.83
(2H, d, J 9), 7.02 (2H, d, J 9), 7.24 (2H, d, J 9), 7.55 (2H, d, J 9),
7.66 (2H, d, J 9), 7.72 (2H, d, J 9); m/z (CI) 495 (M1 1 NH411
2), 493 (M1 1 NH41), 477 (M1 1 2), 475 (M1).
4-[11-(4-Vinylphenyloxy)undecyloxy]phenol 10
The product was derived from 3 (n ~ 11) and hydroquinone
and purified by recrystallisation from hexane to give colourless
crystals (4.56 g, 44%): mp 83 uC (Found: C, 75.5; H, 9.0%.
C25H34O3 requires C, 78.5; H, 8.95%); n(KBr)/cm21 3365 (OH);
dH (CDCl3, 300 MHz, 25 uC) 1.1–2.0 (18H, m), 4.0–4.2 (4H, m),
4.57 (1H, br s), 5.17 (1H, d, J 11), 5.63 (1H, d, J 18), 6.68 (1H,
dd, J 11,18), 6.81 (2H, d, J 9), 6.89 (2H, d, J 9), 6.93 (2H, d, J 9),
7.39 (2H, d, J 9); m/z (CI) 400 (M1 1 NH41), 383 (M1).
4-[11-(4-Bromophenyloxy)undecyloxy]-4’-cyanobiphenyl 20
The product was obtained from 18 and 4-bromophenol
and purified by recrystallisation from CH2Cl2–EtOH to give
colourless crystals (0.80 g, 53%): thermal transitions (uC): K
92.2 N 99.5 I (Found: C, 69.03; H, 6.63; N, 2.51; Br, 15.32%.
C30H34BrNO2 requires C, 69.23; H, 6.58; N, 2.69; Br, 15.35%);
n(thin film)/cm21 2220 (CN); dH (CDCl3, 300 MHz, 25 uC)
1.30–1.60 (14H, m), 1.78–1.88 (4H, m), 3.94 (2H, d, J 7), 4.04
(2H, d, J 7), 6.81 (2H, d, J 9), 7.03 (2H, d, J 9), 7.39 (2H, d, J 9),
7.55 (2H, d, J 9), 7.67 (2H, d, J 9), 7.73 (2H, d, J 9); m/z (CI)
2(3)-Methyl-4-[11-(4-vinylphenyloxy)undecyloxy]phenol 11
The product was obtained from 3 (n ~ 11) and 2-methyl-
hydroquinone as a mixture of two isomers and purified by
recrystallisation from hexane to give colourless crystals (8.74 g,
82%): mp 60–68 uC (Found: C, 78.75; H, 9.05%. C26H36O3
requires C, 78.75; H, 9.15%); n(KBr)/cm21 3365 (OH); dH
(CDCl3, 300 MHz, 25 uC) 1.1–2.0 (18H, m), 2.25 and 2.22 (3H,
s), 4.0–4.2 (4H, m), 4.79 and 4.63 (1H, br s), 5.17 (1H, d, J 11),
5.63 (1H, d, J 18), 6.69 (3H, m), 6.89 (2H, d, J 9), 7.15 (1H, m),
7.39 (2H, d, J 9); m/z (CI) 414 (M1 1 NH41), 397 (M1).
1
539 (M1 1 NH4 1 2), 537 (M1 1 NH41), 523 (M1 1 2),
521 (M1).
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4-[11-(4-Cyanophenyloxy)undecyloxy]-4’-cyanobiphenyl 21
82%): mp 132 uC (Found: C, 84.3; H, 8.25%. C29H34O2 requires
C, 84.0; H, 8.25%); dH (CDCl3, 300 MHz, 25 uC) 0.92 (3H, t,
J 7), 1.4–2.1 (10H, m), 2.62 (2H, t, J 7), 4.0–4.2 (4H, m), 5.11
(1H, d, J 11), 5.60 (1H, d, J 18), 6.67 (1H, dd, J 11,18), 6.8–7.0
(4H, m), 7.21 (2H, d, J 9), 7.34 (2H, d, J 9), 7.50 (4H, m); m/z
(CI) 414 (M1).
The product was obtained from 18 and 4-cyanophenol and
purified by recrystallisation from EtOH–CH2Cl2 to give
colourless crystals (0.75 g, 63%): mp ~ 111.2 uC (Found: C,
80.07; H, 7.28; N, 6.13%. C31H34N2O2 requires C, 79.80; H,
7.34; N, 6.00%); n(thin film)/cm21 2223 (CN); dH (CDCl3,
300 MHz, 25 uC) 1.25–1.55 (14H, m), 1.78–1.88 (4H, m), 3.98–
4.08 (4H, m), 6.97 (2H, d, J 9), 7.03 (2H, d, J 9), 7.58 (2H, d,
The following compounds were prepared using a similar
procedure.
J 9), 7.67 (2H, d, J 9), 7.73 (2H, d, J 9); m/z (CI) 484 (M1
NH41), 566 (M1).
1
4-[11-(4-Vinylphenyloxy)undecyloxy]-4’-n-propylbiphenyl 5
(n ~ 11)
The product was obtained from 8 (n ~ 11) and was purified by
recrystallisation from EtOH to give colourless crystals (5.51 g,
84%): mp 78 uC (Found: C, 83.8; H, 9.3%. C34H44O2 requires
C, 84.5; H, 9.15%); dH (CDCl3, 300 MHz, 25 uC) 0.92 (3H, t,
J 7), 1.1–2.1 (20H, m), 2.62 (2H, t, J 7), 4.0–4.2 (4H, m), 5.11
(1H, d, J 11), 5.60 (1H, d, J 18), 6.67 (1H, dd, J 11,18), 6.8–7.0
(4H, m), 7.21 (2H, d, J 9), 7.34 (2H, d, J 9), 7.50 (4H, m); m/z
(CI) 502 (M1 1 NH41), 485 (M1).
4-[11-(4-Methoxyphenyloxy)undecyloxy]-4’-cyanobiphenyl 22
The product was obtained from 18 and 4-methoxyphenol and
purified by recrystallisation from EtOH to give colourless
crystals (0.84 g, 63%): thermal transitions (uC): K 90.6 (N 78.9)
I (Found: C, 79.28; H, 7.89; N, 2.91%. C31H37NO3 requires C,
78.95; H, 7.91; N, 2.97%); n(thin film)/cm21 2225 (CN); dH
(CDCl3, 300 MHz, 25 uC) 1.30–1.60 (14H, m), 1.73–1.88 (4H,
m), 3.79 (3H, s), 3.93 (2H, t, J 7), 4.02 (2H, t, J 7), 6.85 (4H, s),
7.02 (2H, d, J 9), 7.55 (2H, d, J 9), 7.66 (2H, d, J 9), 7.72 (2H, d,
J 9); m/z (CI) 489 (M1 1 NH41), 472 (M1).
4-[6-(4-Vinylphenyloxy)hexyloxy]-4’-((S)-(1)-2-methylbutyl)-
biphenyl 6 (n ~ 6)
The product was obtained from 9 (n ~ 6) and was purified by
recrystallisation from EtOH to give colourless crystals (1.53 g,
86%): mp 113 uC (Found: C, 84.55; H, 8.4%. C31H38O2 requires
C, 84.1; H, 8.65); dH (CDCl3, 300 MHz, 25 uC) 0.90–0.93 (6H,
m), 1.1–2.0 (11H, m), 2.39 (1H, q, J 7), 2.67 (1H, q, J 7), 4.0–4.2
(4H, m), 5.11 (1H, d, J 11), 5.60 (1H, d, J 18), 6.67 (1H, dd,
J 11,18), 6.90 (4H, m), 7.18 (2H, d, J 9), 7.33 (2H, d, J 9), 7.50
(4H, m); m/z (CI) 460 (M1 1 NH41), 443 (M1).
4-[11-(4-Ethylphenyloxy)undecyloxy]-4’-cyanobiphenyl 23
The product was obtained from 18 and 4-ethylphenol and
purified by recrystallisation from EtOH to give colourless
crystals (0.89 g, 70%): thermal transitions (uC): K 79.0 (N 61.4)
I (Found: C, 81.52; H, 7.95; N, 3.06%. C32H39NO2 requires C,
81.84; H, 8.37; N, 2.98%); n(thin film)/cm21 2226 (CN); dH
(CDCl3, 300 MHz, 25 uC) 1.25 (3H, t, J 8), 1.30–1.60 (14H, m),
1.75–1.90 (4H, m), 2.62 (2H, q, J 8), 3.97 (2H, t, J 7), 4.05 (2H,
t, J 7), 6.86 (2H, d, J 9), 7.02 (2H, d, J 9), 7.14 (2H, d, J 9), 7.56
(2H, d, J 9), 7.68 (2H, d, J 9), 7.74 (2H, d, J 9); m/z (CI) 487
(M1 1 NH41), 469 (M1).
4-[11-(4-Formylphenyloxy)undecyloxy]-4’-((S)-(1)-2-methylbutyl)-
biphenyl 6 (n ~ 11)
The product was obtained from 9 (n ~ 11) and was purified by
recrystallisation from EtOH to give colourless crystals (1.86 g,
83%): mp 67 uC (Found: C, 84.2; H, 9.7%. C36H48O2 requires
C, 84.3; H, 9.45); dH (CDCl3, 300 MHz, 25 uC) 0.90–0.93 (6H,
m), 1.1–2.0 (21H, m), 2.39 (1H, q, J 7), 2.67 (1H, q, J 7), 4.0–4.2
(4H, m), 5.10 (1H, d, J 11), 5.60 (1H, d, J 18), 6.67 (1H, dd,
J 11,18), 6.90 (4H, m), 7.19 (2H, d, J 9), 7.33 (2H, d, J 9), 7.48
(4H, m); m/z (CI) 530 (M1 1 NH41), 513 (M1).
4-[11-(4-Propylphenyloxy)undecyloxy]-4’-cyanobiphenyl 24
The product was obtained from 18 and 4-propylphenol and
purified by recrystallisation from EtOH to give colourless
crystals (0.77 g, 57%): thermal transitions (uC): K 64.2 (N 59.5)
I (Found: C, 81.77; H, 8.65; N, 2.93%. C33H41NO2 requires C,
81.94; H, 8.54; N, 2.90%); n(thin film)/cm21 2229 (CN); dH
(CDCl3, 300 MHz, 25 uC) 0.96 (3H, t, J 7), 1.30–1.70 (16H, m),
1.74–1.91 (4H, m), 2.56 (2H, t, J 8), 3.97 (2H, t, J 7), 4.04 (2H, t,
J 7), 6.85 (2H, d, J 9), 7.03 (2H, d, J 9), 7.12 (2H, d, J 9), 7.56
(2H, d, J 9), 7.67 (2H, d, J 9), 7.73 (2H, d, J 9); m/z (CI) 501
(M1 1 NH41), 483 (M1).
Di-{4-[11-(4-vinylphenoxy)undecyloxy]phenoxy}terephthalate 12
To a solution of terephthaloyl chloride (0.48 g, 2.4 mmol) in
1,2-dimethyloxyethane (10 ml) was added dropwise a solution
of 10 (1.98 g, 5.2 mmol) and pyridine (0.75 g, 9.4 mmol) in 1,2-
dimethyloxyethane (20 ml). The mixture was heated to reflux
and stirred for 72 h. On cooling, the mixture was filtered and
the solvent removed under reduced pressure. The solid residue
was purified by column chromatography (eluent: toluene) and
by repeated precipitation from CH2Cl2 solution by the addition
of EtOH to give a white powder (0.97 g, 46%): thermal tran-
sitions: K 105 N 145 I (Found: C, 77.6; H, 8.15%. C58H70O8
requires C, 77.8; H, 7.9); dH (CDCl3, 300 MHz, 25 uC) 1.1–2.0
(36H, m), 4.0–4.2 (8H, m), 5.17 (2H, d, J 11), 5.63 (2H, d, J 18),
6.71 (2H, dd, J 11,18), 6.90 (8H, m), 7.19 (4H, d, J 9), 7.39 (4H,
d, J 9), 8.38 (4H, s); m/z (EI) 849 (M1).
4-[11-(4-Butylphenyloxy)undecyloxy]-4’-cyanobiphenyl 25
The product was obtained from 18 and 4-butylphenol and
purified by recrystallisation from EtOH–CH2Cl2 to give
colourless crystals (0.68 g, 47%): thermal transitions (uC): K
60.5 N 67.5 I (Found: C, 82.33; H, 8.68; N, 2.66%. C34H43NO2
requires C, 82.05; H, 8.71; N, 2.81%); n(thin film)/cm21 2231
(CN); dH (CDCl3, 300 MHz, 25 uC) 0.95 (3H, t, J 7), 1.30–1.60
(18H, m), 1.74–1.90 (4H, m), 2.58 (2H, t, J 8), 3.97 (2H, t, J 7),
4.05 (2H, t, J 7), 6.85 (2H, d, J 9), 7.03 (2H, d, J 9), 7.11 (2H, d,
J 9), 7.57 (2H, d, J 9), 7.67 (2H, d, J 9), 7.73 (2H, d, J 9), (4H,
m); m/z (CI) 516 (M1 1 NH41), 497 (M1).
The following compound was prepared using a similar
procedure.
4-[6-(4-Vinylphenyloxy)hexyloxy]-4’-n-propylbiphenyl 5 (n ~ 6)
Di-{2(3)-methyl-4-[11-(4-vinylphenoxy)undecyloxy]phenoxy}
terephthalate 13
To a solution of methyltriphenylphosphonium bromide (3.5 g,
9.8 mmol) and potassium tert-butoxide (1.1 g, 9.8 mmol) in
THF (50 ml), a solution of 8 (n ~ 6) (2.7 g, 6.5 mmol) in THF
(15 ml) was added dropwise. After stirring for 1 h, the solvent
was removed under reduced pressure. The solid residue was
purified by column chromatography (eluent: toluene) and by
recrystallisation from EtOH to give colourless crystals (2.21 g,
The product was obtained from 11 and was purified by
recrystallisation from EtOH to give colourless crystals (3.83 g,
77%): thermal transitions: K 72.8 N 107.6 I (Found: C, 77.9;
H, 8.15%. C60H74O8 requires C, 78.5; H, 8.1); dH (CDCl3,
300 MHz, 25 uC) 1.1–2.0 (36H, m), 2.22 and 2.25 (6H, s),
J. Mater. Chem., 2002, 12, 2675–2683
2681

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4.0–4.2 (8H, m), 5.17 (2H, d, J 11), 5.63 (2H, d, J 18), 6.69 (2H,
dd, J 11,18), 6.90 (6H, m), 7.15 (4H, d, J 9), 7.39 (4H, d, J 9),
8.39 (4H, s); m/z (CI) 941 (M1 1 NH41), 923 (M1).
Poly(4-[8-(4-vinylphenyloxy)octyloxy]-4’-cyanobiphenyl) 14
(n ~ 8)
From 1 (n ~ 8) and purified by reprecipitation from CH2Cl2
solution into EtOH (50 mg, 50%): Mn ~ 51 6 103 (average
DP ~ 120); Mw/Mn ~ 1.7; thermal transitions (uC): G 20 S 108
I (Found: C, 81.6; H, 7.15; N, 3.2%. C29H31NO2 requires C,
81.85; H, 7.35; N, 3.3%); n(KBr)/cm21 2220 (CN); dH (CDCl3,
300 MHz, 25 uC) 1.2–1.9 (15H, br m), 3.9–4.1 (4H, br m), 6.2–
6.8 (4H, br m), 6.96 (2H, d, J 9), 7.49 (2H, d, J 9), 7.61 (4H, m).
Poly(4-[11-(4-vinylphenyloxy)undecyloxy]-4’-cyanobiphenyl) 14
(n ~ 11)
To a Pyrex glass ampoule was added 1 (n ~ 11) (0.5 g,
1.1 mmol), AIBN (1.5 mg, 7.8 6 1023 mol), anhydrous THF
(1.5 ml) and a magnetic stirrer bar. The mixture was cooled by
liquid nitrogen and subjected to a high vacuum (y0.1 mm Hg).
On warming, this degassing process was repeated two further
times. The sealed ampoule was placed in an oil bath at 65 uC
and the solution stirred for 72 h. On cooling, the solution was
added dropwise to light petroleum (bp 60–80) and the crude
product was collected by filtration. The polymer was purified
by repeated precipitation from THF solution by adding to light
petroleum until no significant amount of monomer (i.e. less
than 1%) was observed by 1H NMR spectroscopy. The polymer
was obtained as a white powder (200 mg, 40%): Mn ~ 64 6
103 (average DP ~ 140); Mw/Mn ~ 2.2; thermal transitions
(uC): G 12 S 114 I (Found: C, 81.9; H, 7.85; N, 3.0%.
C32H37NO2 requires C, 82.2; H, 8.0; N, 3.0%); n(KBr)/cm21
2220 (CN); dH (CDCl3, 300 MHz, 25 uC) 1.1–1.9 (21H, br m),
3.9–4.1 (4H, br m), 6.2–6.7 (4H, br m), 6.97 (2H, d, J 9),
7.51 (2H, d, J 9), 7.61 (4H, m).
Poly(4-[9-(4-vinylphenyloxy)nonyloxy]-4’-cyanobiphenyl) 14
(n ~ 9)
From 1 (n ~ 9) and purified by reprecipitation from CH2Cl2
solution into EtOH (603 mg, 64%): Mn ~ 51 6 103 (average
DP ~ 120); Mw/Mn ~ 1.7; thermal transitions (uC): G 19 S 114
I (Found: C, 81.78; H, 7.72; N, 3.17%. C30H33NO2 requires C,
81.97; H, 7.57; N, 3.19%); n(KBr)/cm21 2220 (CN); dH (CDCl3,
300 MHz, 25 uC) 1.2–1.9 (17H, br m), 3.9–4.1 (4H, br m), 6.15–
6.75 (4H, br m), 6.96 (2H, d, J 9), 7.49 (2H, d, J 9), 7.61 (4H, m).
Poly(4-[10-(4-vinylphenyloxy)decyloxy]-4’-cyanobiphenyl) 14
(n ~ 10)
From 1 (n ~ 1) and purified by reprecipitation from CH2Cl2
solution into EtOH (500 mg, 46%): Mn ~ 51 6 103 (average
DP ~ 120); Mw/Mn ~ 1.7; thermal transitions (uC): G 18 S 118
I (Found: C, 81.56; H, 7.74; N, 2.98%. C31H35NO2 requires C,
82.08; H, 7.78; N, 3.09%); n(KBr)/cm21 2220 (CN); dH (CDCl3,
300 MHz, 25 uC) 1.2–1.9 (19H, br m), 3.9–4.1 (4H, br m), 6.2–
6.8 (4H, br m), 6.96 (2H, d, J 9), 7.49 (2H, d, J 9), 7.61 (4H, m).
The following polymers were prepared using a similar
procedure.
Poly(4-[4-(4-vinylphenyloxy)butyloxy]-4’-cyanobiphenyl) 14
(n ~ 4)
From 1 (n ~ 4) and purified by reprecipitation from CH2Cl2
solution into EtOH (50 mg, 5%): Mn ~ 37 6 103 (average DP
~ 102); Mw/Mn ~ 2.2; thermal transition: G 77 I (Found: C,
80.7; H, 6.6; N, 4.1%. C25H23NO2 requires C, 81.25; H, 6.30; N,
3.80%); n(KBr)/cm21 2220 (CN); dH (CDCl3, 300 MHz, 25 uC)
1.2–1.9 (7H, br m), 3.9–4.1 (4H, br m), 6.2–6.8 (4H, br m), 6.92
(2H, br s), 7.42 (2H, br s), 7.60 (4H, br s).
Poly(4-[6-(4-vinylphenyloxy)hexyloxy]-4’-n-propylbiphenyl) 15
(n ~ 6)
From 5 (n ~ 6) and purified by reprecipitation from THF
solution into light petroleum (bp 30–60 uC) (600 mg, 60%):
Mn ~ 48 6 103 (average DP ~ 116); Mw/Mn ~ 2.8; thermal
transitions (uC): G 94 S 139 I (Found: C, 84.0; H, 8.2%.
C29H34O2 requires C, 83.2; H, 8.19%); dH (CDCl3, 300 MHz,
25 uC) 0.92 (3H, t, J 7), 1.2–1.8 (13H, br m), 2.58 (2H, br s),
3.8–4.0 (4H, br m), 6.2–6.7 (4H, br m), 6.83 (2H, d, J 9), 7.14
(2H, d, J 9), 7.38 (4H, m).
Poly(4-[5-(4-vinylphenyloxy)pentyloxy]-4’-cyanobiphenyl) 14
(n ~ 5)
From 1 (n ~ 5) and purified by reprecipitation from CH2Cl2
solution into EtOH (40 mg, 13%): Mn ~ 62 6 103 (average
DP ~ 161); Mw/Mn ~ 2.2; thermal transition: G 59 I (Found:
C, 81.7; H, 6.4; N, 3.5%. C26H25NO2 requires C, 81.4; H, 6.6;
N, 3.65%); n(KBr)/cm21 2220 (CN); dH (CDCl3, 300 MHz,
25 uC) 1.1–1.9 (9H, br m), 3.9–4.1 (4H, br m), 6.1–6.7 (4H, br
m), 6.82 (2H, d, J 9), 7.38 (2H, d, J 9), 7.61 (4H, m).
Poly(4-[11-(4-vinylphenyloxy)undecyloxy]-4’-n-propylbiphenyl)
15 (n ~ 11)
From 5 (n ~ 11) and purified by reprecipitation from THF
solution into light petroleum (bp 30–60 uC) (270 mg, 27%):
Mn ~ 70 6 103 (average DP ~ 144); Mw/Mn ~ 2.8; thermal
transition (uC): S 118 I (Found: C, 83.8; H, 9.6%. C29H34O2
requires C, 84.25; H, 9.15%); dH (CDCl3, 300 MHz, 25 uC) 0.92
(3H, t, J 7), 1.1–1.8 (23H, br m), 2.58 (2H, br s), 3.8–4.0 (4H,
br m), 6.2–6.7 (4H, br m), 6.85 (2H, d, J 9), 7.18 (2H, d, J 9),
7.41 (4H, m).
Poly(4-[6-(4-vinylphenyloxy)hexyloxy]-4’-cyanobiphenyl) 14
(n ~ 6)
From 1 (n ~ 6) and purified by reprecipitation from CH2Cl2
solution into EtOH (290 mg, 58%): Mn ~ 35 6 103 (average
DP ~ 88); Mw/Mn ~ 1.9; thermal transitions (uC): G 40 S 110 I
(Found: C, 81.5; H, 7.3; N, 3.3%. C27H27NO2 requires C, 81.6;
H, 6.85; N, 3.55%); n(KBr)/cm21 2220 (CN); dH (CDCl3,
300 MHz, 25 uC) 1.1–1.9 (11H, br m), 3.9–4.1 (4H, br m), 6.1–
6.8 (4H, br m), 6.95 (2H, d, J 9), 7.44 (2H, d, J 9), 7.61 (4H, m).
Poly(4-[6-(4-vinylphenyloxy)hexyloxy]-4’-((S)-(1)-2-methylbutyl)-
biphenyl) 16 (n ~ 6)
Poly(4-[7-(4-vinylphenyloxy)heptyloxy]-4’-cyanobiphenyl) 14
(n ~ 7)
From 6 (n ~ 6) and purified by reprecipitation from THF
solution into light petroleum (bp 30–60 uC) (153 mg, 17%):
Mn ~ 40 6 103 (average DP ~ 90); Mw/Mn ~ 4.32; thermal
transition (uC): S 68 I (Found: C, 83.65; H, 8.8%. C31H38O2
requires C, 84.1; H, 8.65%); dH (CDCl3, 300 MHz, 25 uC) 0.89
(6H, br m), 1.1–1.8 (14H, br m), 2.26 (1H, br m), 2.54 (1H, br
m), 3.7–4.0 (4H, br m), 6.2–6.7 (4H, br m), 6.80 (2H, d, J 9),
7.04 (2H, d, J 9), 7.36 (4H, m).
From 1 (n ~ 7) and purified by reprecipitation from CH2Cl2
solution into EtOH (170 mg, 57%): Mn ~ 16 6 103 (average
DP ~ 40); Mw/Mn ~ 1.7; thermal transitions (uC): G 28 S 79 I
(Found: C, 80.95; H, 7.7; N, 3.15%. C28H29NO2 requires C,
81.7; H, 7.1; N, 3.4%); n(KBr)/cm21 2220 (CN); dH (CDCl3,
300 MHz, 25 uC) 1.1–1.9 (13H, br m), 3.9–4.1 (4H, br m), 6.1–
6.8 (4H, br m), 6.99 (2H, d, J 9), 7.51 (2H, d, J 9), 7.63 (4H, m).
2682
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6
7
8
9
H. Johnson, H. Andersson, P. E. Sundell, U. W. Gedde and
A. Hult, Polym. Bull., 1991, 25, 641.
G. G. Kostromin, N. D. Cuong, E. S. Garina and V. P. Shibaev,
Mol. Cryst. Liq. Cryst., 1990, 193, 177.
J. Lub, D. J. Broer and G. N. Mol, Macromolecules, 1993, 26,
1736.
Poly(4-[11-(4-vinylphenyloxy)undecyloxy]-4’-((S)-(1)-2-methyl-
butyl)biphenyl) 16 (n ~ 11)
From 6 (n ~ 11) and purified by reprecipitation from THF
solution into light petroleum (bp 30–60 uC) (350 mg, 35%):
Mn ~ 21 6 103 (average DP ~ 41); Mw/Mn ~ 2.1; thermal
transitions (uC): G 30 S 88 I (Found: C, 84.5; H, 9.55%.
C36H48O2 requires C, 84.3; H, 8.45%); dH (CDCl3, 300 MHz,
25 uC) 0.88 (6H, br m), 1.0–1.8 (24H, br m), 2.33 (1H, br m),
2.61 (1H, br m), 3.7–4.0 (4H, br m), 6.2–6.7 (4H, br m), 6.89
(2H, d, J 9), 7.12 (2H, d, J 9), 7.40 (4H, m).
Z. Ali-Adib, P. M. Budd, N. B. McKeown and K. Thanapprapasr,
J. Mater. Chem., 2000, 10, 2270.
10 H. Andersson, M. Trollsas, U. W. Gedde and A. Hult, Macromol.
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11 S. E. Williamson, D. Kang and C. E. Hoyle, Macromolecules,
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12 S. Makhseed, A. Cook and N. B. McKeown, Chem. Commun.,
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13 G. W. Gray and A. Mosley, J. Chem. Soc., Perkin Trans. 2, 1976,
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14 C. T. Imrie and G. R. Luckhurst, J. Mater. Chem., 1998, 8,
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Acknowledgements
We thank EPSRC for CASE studentships (A. C. and S. B.) and
Merck Speciality Chemicals Ltd., NB-SC for funding.
15 J. W. Emsley, G. R. Luckhurst, G. N. Shilstone and I. Sage, Mol.
Cryst. Liq. Cryst., 1984, 102, 223.
16 D. J. Broer, G. Challa and R. A. M. Hikmet, Makromol. Chem.,
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