Tetraphenylethene-derived columnar liquid crystals and their oxidative photocyclization

Article abstract of DOI:10.1002/ejoc.200300118

The synthesis of novel tetraphenylethenes 9a-f, 13, and 18a,b bearing ether, biphenyl, and 4-cyanobiphenyl moieties via a McMurry reaction and Suzuki coupling as key steps is described. Mesogenic properties of these compounds were studied by differential

Full text of DOI:10.1002/ejoc.200300118

FULL PAPER
Tetraphenylethene-Derived Columnar Liquid Crystals and Their Oxidative
Photocyclization
Andreas Schultz,[a] Sabine Laschat,*[b] Siegmar Diele,[c] and Manfred Nimtz[d]
Keywords: Liquid crystals / Phenanthrene / Photoreaction / Tetraphenylethenes
The synthesis of novel tetraphenylethenes 9a−f, 13, and
18a,b bearing ether, biphenyl, and 4-cyanobiphenyl moieties
via a McMurry reaction and Suzuki coupling as key steps is
chains, respectively, formed hexagonal columnar meso-
phases. Oxidative photocyclization of compounds 1f, 9c, 13,
and 18a were investigated. Upon irradiation in the presence
described. Mesogenic properties of these compounds were of iodine tetraphenylethenes 1f, 9c gave the corresponding
studied by differential scanning calorimetry (DSC), optical
polarizing microscopy, and X-ray diffraction. Ether-substi-
phenanthrenes 22a,b. The mesomorphic properties of 22a,b
were strongly dependent on the substituent. Whereas ether
tuted derivatives 9a,b with chain lengths C8 or C9 were non- 22a displayed only isotropic melting, a hexagonal columnar
mesogenic. Compounds 9c−f with longer alkyl chains dis-
played hexagonal columnar mesophases. Whereas cyanobi-
phenyl derivative 13 was non-mesogenic, the corresponding
biphenyl systems 18a,b with decyloxy and dodecyloxy
mesophase was found for ester 22b.
( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2003)
Introduction
unit. In addition we were particularly interested in the oxi-
dative photocyclization of tetraphenylethenes because this
reaction should provide a novel mesogenic unit. cis-Stil-
benes and tetraphenylethenes are well-known to undergo
oxidative photocyclization to phenanthrenes.[8Ϫ10] However,
to the best of our knowledge this cyclization has not been
used for the preparation of liquid crystalline phen-
anthrenes.[11] Here we describe the synthesis and meso-
morphic properties of tetraphenylethenes and their photo-
cyclization towards phenanthrenes.
There is considerable interest in the development of novel
columnar liquid crystals[1] resulting from their unique one-
dimensional transport properties such as electrical conduc-
tivity[2] and photo-conductivity.[3,4] For a long time the
presence of a large flat aromatic core connected with flex-
ible side chains was assumed to be an ultimate prerequisite
for the formation of thermotropic columnar mesophases.
However, contributions from several laboratories over the
last couple of years indicated that even molecules devoid of
a disk-like core region can be used as columnar mesogens[5]
because the major driving force for mesophase formation is
microsegregation of the polar cores from the lipophilic alkyl
side chains rather than intracolumnar πϪπ stacking be-
tween the core regions.[6] We have recently discovered that
tetraphenylethenes condensed with gallic acid derivatives
(1) represent a novel class of columnar liquid crystals, de-
spite the twisting of the aryl rings (Scheme 1).[7] Thus it
seemed attractive to study the scope of this mesogenic sub-
[a]
Institut für Organische Chemie, Technische Universität
Braunschweig,
Hagenring 30, 38106 Braunschweig, Germany
[b]
Institut für Organische Chemie, Universität Stuttgart,
Pfaffenwaldring 55, 70569 Stuttgart, Germany
E-mail: sabine.laschat@po.uni-stuttgart.de
[c]
Institut für Physikalische Chemie, Martin-Luther Universität
Halle-Wittenberg,
Mühlpforte 1, 06108 Halle, Germany
[d]
Gesellschaft für Biotechnologische Forschung
Mascheroder Weg 1, 38124 Braunschweig, Germany
Scheme 1. Tetraphenylethene esters 1aϪg
Eur. J. Org. Chem. 2003, 2829Ϫ2839
DOI: 10.1002/ejoc.200300118
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A. Schultz, S. Laschat, S. Diele, M. Nimtz
FULL PAPER
Results and Discussion
In order to explore the scope and limitations of the tetra-
phenylethene mesogenic subunit, it was decided to prepare
the corresponding ether, biphenyl, and 4-cyanobiphenyl de-
rivatives and to compare them with the esters 1. As the key
step for the formation of the tetraphenylethene moiety the
McMurry reaction of suitable modified 4,4Ј-disubstituted
benzophenones was chosen.[7,12,13]
Synthesis and Mesomorphic Properties of
Tetraphenylethene Derivatives 9
As outlined in Scheme 2, compound 3,4,5-trimethoxyani-
line (2) was treated with NaNO2 under acidic conditions
following the procedure by Banwell. Subsequent Sandmeyer
reaction of the diazonium salt with CuBr under reflux gave
the bromide 3 in 70% yield.[14] Coupling of bromide 3 with
4,4Ј-dihydroxybenzophenone (4a) was achieved by heating
the compounds with CuO in the presence of K2CO3 in pyri-
dine at 140 °C.[15] After 5 days, a mixture of the bis-arylated
compound 6 (34%) and the mono-arylated product 5 (24%)
was obtained, which could be separated by flash chroma-
tography. The methoxy groups in 6 were removed with BBr3
in CH2Cl2, yielding the hexahydroxy derivative 7 in 71%,
which was alkylated under standard conditions using
K2CO3 in DMF at 80 °C to give the corresponding hexa-
alkyloxybenzophenones 8aϪf in moderate to good yields
(Table 1). Final McMurry coupling of benzophenones 8aϪf
was achieved with TiCl4 and Zn powder in CH2Cl2 in the
presence of pyridine to afford the tetraphenylethenes 9aϪf
in 34Ϫ61% (Table 2).
The mesomorphic properties of tetraphenylethene ethers
9aϪf and their precursors 8aϪf were studied by differential
scanning calorimetry (DSC) and optical polarizing mi-
croscopy. As shown in Table 1, benzophenones 8aϪe did
not show any mesomorphic properties. Compound 8f dis-
played two endothermic peaks at 45 °C and 53 °C upon
first heating, which may be correlated to crystal Ǟ crystal
and crystal Ǟ isotropic liquid transitions, respectively.
These two transitions reappear during the cooling cycle at
41 °C and 39 °C. On further heating only isotropic melting
at 44 °C was observed. Microscopy revealed no character-
istic textures between 53 °C and 45 °C.
Scheme 2. Tetraphenylethene ethers 9: a) 1. NaNO2, H2SO4, H2O,
10 °C, 2. CuBr, H2O, reflux, 30 min; b) CuO, pyridine, K2CO3, 140
°C, 5 d; c) BBr3 (7 equiv.), CH2Cl2, Ϫ60 °C, 1 h, then room temp.,
16 h; d) K2CO3 (13 equiv.), DMF, RBr (6 equiv.), 80 °C, 40 h;
e) TiCl4, Zn, pyridine, CH2Cl2, 60 °C, 20 h
Table 1. Yields and phase-transition temperatures of benzo-
phenones 8
8[a]
Yield (%)
Temp.[b] [°C] for Cr Ǟ I[c]
The phase transition temperatures of tetraphenylethenes
9aϪf are summarized in Table 2. Whereas the octyl- and
nonyl-substituted derivatives 9a,b show only isotropic melt-
ing upon heating, the compounds 9cϪf with longer alkoxy
chains displayed an interesting phase behavior. During first
heating of the decyloxy-substituted tetraphenylethene 9c
isotropic melting at 38 °C was observed. Upon cooling of
the isotropic phase below 4 °C a columnar mesophase ap-
peared, which could not be transformed into the crystalline
phase even upon prolonged cooling and storage at subam-
bient temperatures. When the columnar mesophase was re-
a
b
c
d
e
f
83
73
48
89
58
65
37
33
50
44
42
45
[a]
Preparation of 8 from 7 under the reaction conditions shown in
[b]
Scheme 2.
Transition temperatures were determined by DSC
upon first heating (heating rate 10 K·minϪ1).
The following
[c]
phases were observed: Cr (crystalline), I (isotropic).
heated, a clearing transition at 16 °C was observed. This crystal Ǟ isotropic liquid phase transitions in DSC. How-
cycle could be repeated several times. Compounds 9d,e be- ever, upon rapid cooling from the isotropic phase fan-
haved similarly. In contrast, derivative 9f displayed only shaped textures indicative for columnar mesophases were
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Eur. J. Org. Chem. 2003, 2829Ϫ2839

Tetraphenylethene-Derived Columnar Liquid Crystals
FULL PAPER
Table 2. Yields and phase-transition temperatures of tetraphenylethenes 9
9[a]
Yield (%)
Temp. cycle
Temp.[b] [°C]
Enthalpies [kJ·molϪ1
]
Transitions[c]
a
b
c
c
c
d
d
d
e
e
e
f
55
57
49
1st heating
1st heating
1st heating
1st cooling
2nd heating
1st heating
1st cooling
2nd heating
1st heating
1st cooling
2nd heating
1st heating
1st cooling
2nd heating
54[d]
43[d]
38
4
16
42
11
17
52
17
23
43
36
43
Ϫ[e]
Cr Ǟ I
Cr Ǟ I
Cr Ǟ I
Ϫ[e]
6.90
Ϫ3.88
7.98
134
Ϫ7.14
6.58
158
Ϫ9.15
8.78
224
Ϫ220
212
I Ǟ Colh
Colh Ǟ I
Cr Ǟ I
I Ǟ Colh
Colh Ǟ I
Cr Ǟ I
I Ǟ Colh
Colh Ǟ I
Cr Ǟ I
51
34
61
[f]
f
I Ǟ Cr
f
Cr Ǟ I[f]
[a] Preparation of 9 from 8 under the reaction conditions shown in Scheme 2. [b] Transition temperatures were determined by DSC (heating
[c]
[d]
rate 10 K· minϪ1). The following phases were observed: Cr (crystalline), Colh (hexagonal columnar), I (isotropic). Phase transitions
[e]
[f]
were determined by optical polarizing microscopy.
croscopy.
Not determined. A hexagonal columnar mesophase was observed during mi-
detected for 9f. Similar optical results were obtained for THF, followed by quenching with trimethylborate. Suzuki
9cϪe.[16] As a typical example the texture of 9e at 11 °C is coupling of tetrakis(p-bromophenyl)ethene (15), easily
shown in Figure 1.
available by neat bromination of tetraphenylethene (14) ac-
cording to a procedure by Morris,[19] with boronic acid 11
gave the desired 4-cyanobiphenyl derivative 13 in 62%
yield (Scheme 4).
Scheme 3
Figure 1. Fan-shaped texture of tetraphenylethene 9e as seen be-
tween crossed polarizers at 11 °C upon cooling (cooling rate:
0.1 K·minϪ1) from the isotropic liquid (magnification 200 ϫ)
Compound 13 did not show any mesomorphic properties.
Upon heating isotropic melting at 337 °C was observed.
Due to decomposition above the melting point, no cooling
cycles could be studied by DSC.
The uneventfully proceeding Suzuki coupling of boronic
acid 12 with tetrabromide 15 afforded the tetraphenylethene
16 in 56% yield. Removal of the methoxy groups with BBr3
as described above was achieved in 92%. Disappointingly,
upon alkylation of dodecahydroxy derivative 17 with dode-
cycl bromide only 7% of the desired tetraphenylethene 18b
could be obtained. In order to improve the yield, we de-
cided to prepare alternatively a fully functionalized benzo-
Non-oriented samples of 9d,e were investigated by X-ray
studies at 14 °C and 19 °C, respectively, during the second
heating run. Only one reflection (d ϭ 2.97 nm for 9d and
d ϭ 3.33 nm for 9e) could be detected. With respect to the
texture observation these reflections were indexed as 10 re-
flections of a hexagonal lattice leading to the lattice param-
eters ahex ϭ 3.43 nm and ahex ϭ 3.85 nm.[17]
Synthesis and Mesomorphic Properties of
Tetraphenylethene Derivatives 18
For the synthesis of the biphenyl derivatives a Suzuki phenone precursor which should undergo final McMurry
coupling was chosen.[18] As shown in Scheme 3, the re- coupling to the tetraphenylethene derivative 18a. As shown
quired boronic acids 11 and 12 were prepared in 37% and in Scheme 5, compound 4,4Ј-dibromobenzophenone (4b)
64% yield, respectively, from 4-bromobenzonitrile (10) and almost quantitatively underwent Suzuki coupling with bo-
3,4,5-trimethoxybenzene (3) by treatment with BuLi in ronic acid 12 to ketone 19. Deprotection and alkylation
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A. Schultz, S. Laschat, S. Diele, M. Nimtz
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In the DSC experiment biphenyl derivative 18b displayed
a melting transition at 49 °C (131.2 kJ·molϪ1) and an en-
antiotropic clearing transition at 65 °C (10.5 kJ·molϪ1).
During subsequent cooling and heating cycles no crystalline
phase was observed, but the clearing transition between me-
sophase and isotropic liquid was fully reversible. This ob-
servation agreed well with the optical investigations. Upon
slow cooling from the isotropic liquid a fan-shaped texture
was observed.[16] Further support came from X-ray studies
of non-oriented samples. The diffraction pattern could be
traced back to a hexagonal columnar lattice with a lattice
parameter ahex ϭ 3.5 nm for 18b.[17]
Photocyclization to Phenanthrene Derivatives 22
The results of the oxidative photocyclizations of tetra-
phenylethenes 13, 18a, 9c, and 1f (R ϭ C10H21) are summa-
rized in Scheme 6. Following the procedure by Olsen and
Buckles,[20] solutions of the tetraphenylethenes 13, 18a, 9c,
or 1f in toluene were irradiated with a daylight lamp in the
presence of 1 equiv. of iodine. Whereas the 4-cyanobiphenyl
derivative 13 and trisalkoxybiphenyl derivative 18a did not
give any trace of the desired phenanthrene, photocycliza-
tions of ether 9c and ester 1f were successful. However,
compounds 9c and 1f differed remarkably in their reactivity.
Upon irradiation of ether 9c the corresponding phen-
anthrene 22a was isolated after 2 days in 73% yield. In con-
trast, irradiation of ester 1f gave phenanthrene 22b after 7
days in only 31% yield. The different reaction rates could
even be observed in the solid state. Solutions of tetraphenyl-
ethenes 9c or 1f in CH2Cl2 were dropped onto cover glasses
and the solvent was evaporated. The solid samples were ir-
radiated overnight in the presence of air at λ ϭ 254 nm
(commercial UV lamp). Reaction monitoring by TLC indi-
cated almost complete conversion of 9c to 22a after 12 h.
In contrast, conversion of 1f to 22b was only poor, showing
mainly starting material 1f. In the photocyclizations no
trace of the corresponding dibenzo[g,p]chrysenes was found
in the crude products. This result agrees well with earlier
works of Davidson[21] and Mitchell.[22] The latter author
reported that the failure of 9,10-diphenylphenanthrene de-
rivatives to undergo a second photocyclization to the corre-
sponding dibenzo[g,p]chrysenes is not due to steric hin-
drance of the ortho hydrogen atoms. In contrast, under
Scholl conditions (AlCl3, nitrobenzene) 9,10-diphenylphen-
anthrenes are clearly converted into the dibenzo[g,p]chrys-
enes. However, the chrysene derivatives turned out to be
very sensitive towards oxygen. Thus, Mitchell concluded
that even if the chrysenes are formed during double oxidat-
ive photocyclization, they immediately decompose under
the reaction conditions. This is probably true in our cases
as well.
Scheme 4. Preparation of tetraphenylethene derivatives: a) Br2,
room temp., 16 h; b) 11, Pd(PPh3)4 (15 mol %), Na2CO3, DME,
H2O, 100 °C, 18 h; c) 12, Pd(PPh3)4 (15 mol %), Na2CO3, DME,
H2O, 100 °C, 24 h; d) BBr3 (13 equiv.), CH2Cl2, Ϫ60 °C Ǟ room
temp., 16 h; e) K2CO3 (25 equiv.), DMF, C12H25Br (12 equiv.), 80
°C, 3 days
with decyl bromide proceeded in 72% and 83%, respectively,
and the final McMurry coupling of 21 gave the tetraphenyl-
ethene 18a in 28% yield.
However, the most surprising result was discovered by
examining compounds 22a,b by microscopy and DSC.
Ether-substituted phenanthrene 22a did not show any me-
somorphic properties. During several heating and cooling
cycles only isotropic melting from the crystalline phase at
49 °C was observed. In contrast, ester-substituted phen-
anthrene 22b displayed a fan-shaped texture between 110
Scheme 5. Tetrakis[4-(3,4,5-trisdecyloxyphenyl)phenyl]ethene:
a) 12, Pd(PPh3)4 (8 mol %), Na2CO3, DME, H2O, 100 °C, 60 h;
b) BBr3 (7 equiv.), CH2Cl2, Ϫ78 °C Ǟ room temp., 18 h; c) K2CO3
(12 equiv.), DMF, C10H21Br (6 equiv.), 80 °C, 4 d; d) TiCl4, Zn,
pyridine, CH2Cl2, 50 °C, 24 h
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Tetraphenylethene-Derived Columnar Liquid Crystals
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Obviously, the formation of the mesophase is kinetically
hindered in these systems. This would also explain why an
extremely slow cooling rate is required in order to obtain a
suitable mesophase.
Scheme 6. Photocyclization
Figure 2. Fan-shaped texture of phenanthrene 22b as seen between
crossed polarizers at 116 °C upon cooling (cooling rate:
0.1 K·minϪ1) from the isotropic liquid (magnification 200 ϫ)
°C and 121 °C under the microscope (Figure 2). The DSC
curves of 22b revealed another interesting feature of this
novel mesogenic subunit. As can be seen from Table 3, the
clearing enthalpy for a given temperature cycle is much
Thus, rigidifying the mesogenic core of the tetraphenyl-
larger than the corresponding melting enthalpy. Usually the ethene to the phenanthrene moiety resulted in a strong in-
reverse is true for columnar liquid crystals[1] as exemplified crease of the melting and clearing points together with de-
by the transition enthalpies of tetraphenylethene 18b. The creased width of the mesophase. While the former result
large clearing enthalpy of 22b is probably caused by rela- seems reasonable, the latter outcome is somewhat unexpec-
tively strong long-range orientational order of the columnar ted. In Figure 3 possible arrangements of tetraphenyleth-
mesophase, which is evident in the extremely high viscosity. enes 1f, 9c, and phenanthrenes 22a,b are shown. Presum-
The X-ray diffraction displays two weak reflections at d ϭ ably C2-symmetrical tetraphenylethenes 9c, 1f can better ac-
4.3 nm (first order) and d ϭ 2.15 nm (second order) after commodate the columnar orientation in the mesophase, by
slow cooling from the isotropic state into the liquid crystal- stacking neighboring tetraphenylethenes, which are rotated
line one. This pattern would indicate a layer structure. But against each other by 90° (Figure 3, a). Slight deviations
with respect to the texture of the phase the pattern has been from the 90° angle are tolerated in this case. However, two
evaluated on the basis of a Colhex structure because often neighboring phenanthrenes 22a,b must be rotated by 180°
the √3 reflection is of extreme low intensity and cannot be against each other in order to maintain sufficient space be-
observed. A lattice parameter a ϭ 4.96 nm of the hexagonal tween the planar phenanthrene system and the twisted aryl
cell was obtained. Simultaneously with the Bragg reflec- rings (Figure 3, b). There are no deviations from the 180°
tions a diffuse scattering can be seen in the small angle re- angle possible and thus the tendency to crystallize is
gion which indicates the presence of the isotropic phase.[16] strongly enhanced. Of course the crystalline phase is further
Table 3. Phase transition temperatures of tetraphenylethenes 18a (R ϭ C10H21), 18b (R ϭ C12H25) and phenanthrenes 22a,b (R ϭ C10H21)
18, 22[a]
Temp. cycle
Temp.[b] [°C] (enthalpies [kJ·molϪ1])
18a
18a
18a
18b
18b
18b
22a
22a
22a
22b
22b
22b
1st heating
1st cooling
2nd heating
1st heating
1st cooling
2nd heating
1st heating
1st cooling
2nd heating
1st heating
1st cooling
2nd heating
Cr
I
Cr
Cr
I
Colh
Cr1
I
Cr2
Cr2
I
65 (9.85)
54 (Ϫ8.71)
61 (8.60)
49 (131.2)
61 (Ϫ9.65)
66 (10.1)
29 (0.44)
48 (Ϫ82.8)
47 (61.6)
110 (1.91)
119 (Ϫ24.7)
98 (2.35)
I[c]
Cr
I
Colh
Colh
I
Cr2
Cr
I
65 (10.5)
49 (84.0)
I
I
Colh
Colh
Cr2
121 (26.2)
101 (Ϫ0.73)
106 (Ϫ2.43)
I
Cr2 97 (Ϫ1.19) Cr1
Colh 121 (Ϫ25.0) I
Cr1
[a]
[b]
Preparation of 18, 22 under the reaction conditions shown in Schemes 4Ϫ6.
Transition temperatures were determined by DSC
(heating rate 10 K·minϪ1). The following phases were observed: Cr, Cr1, Cr2 (crystalline), Colh (hexagonal columnar), I (isotropic).
[c]
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A. Schultz, S. Laschat, S. Diele, M. Nimtz
FULL PAPER
(2.03 g, 32.0 mmol), NaBr (15.4 g, 0.15 mol), concd. H2SO4
(1.6 mL), and H2O (100 mL) for 3 h). The mixture was refluxed for
additional 30 min, cooled to room temp. and diluted with Et2O
(250 mL). The aqueous layer was extracted with Et2O (2 ϫ
250 mL) and the combined organic layers were washed with sat.
NaHCO3 (2 ϫ 250 mL), dried (MgSO4), and the solvents evapo-
rated. Flash chromatography on SiO2 (hexanes/ethyl acetate, 3:1)
yielded 17.3 g (70%) of a colorless solid; m.p. 78 °C. 1H NMR
(200 MHz, CDCl3): δ ϭ 6.70 (s, 2 H, 4-,6-H), 3.83, 3.80 (s, 9 H,
OCH3) ppm. 13C NMR (50 MHz, CDCl3): δ ϭ 153.9 (C-1, C-3),
stabilized by the increased πϪπ stacking interaction of
phenanthrenes 22a,b as compared to tetraphenylethenes 9c,
1f.[23] In order to maximize overlap between neighboring
phenanthrenes 22, antiparallel stacking is required, re-
sulting in a larger lattice parameter for 22b as compared
to tetraphenylethenes 9c, 1f. Comparison of the molecular
diameters of 9d,e and 18b, which were estimated from
CoreyϪPaulingϪKolton (CPK) models (9d: 4.1 nm, 9e:
5.2 nm, 18b: 5.0 nm), with the experimental lattice param-
eter suggests a partial interdigitation of the aliphatic side 137.7 (C-2), 116.1 (C-5), 108.9 (C-4, C-6), 60.8, 56.3 (OCH3) ppm.
MS (EI): m/z (%) ϭ 248 (96), 246 (100) [Mϩ], 233 (60), 231 (62),
205 (20), 203 (22), 190 (14), 188 (18), 175 (10), 173 (12), 157 (3),
chains of neighboring columns. In contrast, the columnar
arrangement for compound 22b (Figure 3, b) has a diam-
eter of 5.2 nm based on CPK models. This corresponds well
with experimental lattice parameter, proposing only little
137 (3), 124 (18), 109 (5), 94 (3), 81 (5). Analytical data were in
accordance with the literature.[14]
overlap between the side chains. It should be mentioned
4,4Ј-Bis(3,4,5-trimethoxyphenyloxy)benzophenone (6): A mixture of
4a (1.50 g, 7.00 mmol), (3.45 g, 14.0 mmol), CuO (1.68 g,
that Artal et al.[24] studied FeCl3-mediated cyclization of
3
alkoxy-substituted 1,2,4,5-tetraphenylbenzenes to the corre- 21.0 mmol), and K2CO3 (1.94 g, 14.0 mmol) in pyridine (30 mL)
was heated at 140 °C for 5 days. The mixture was then cooled to
room temp., diluted with CH2Cl2 (200 mL), and filtered. The or-
ganic layer was stirred for 2 h with 10% HCl (2 ϫ 200 mL), washed
with sat. NaHCO3 (200 mL) and H2O (200 mL), dried (MgSO4),
and the solvents evaporated. After purification by flash chromatog-
raphy on SiO2 (CH2Cl2/ethyl acetate, 10:1) and recrystallization
from CH2Cl2/hexanes, compounds 5 (0.64 g, 24%) and 6 (1.29 g,
34%) were obtained as colorless solids.
sponding tetrabenz[a,c,h,j]anthracenes. Whereas the tetra-
phenylbenzenes displayed only isotropic melting behavior,
the board-like tetrabenz[a,c,h,j]anthracenes formed crystal
B and hexagonal columnar mesphases.
4-Hydroxy-4Ј-(3,4,5-trimethoxyphenyloxy)benzophenone (5): M.p.
1
173 °C. IR (KBr): ν˜ ϭ 1630 cmϪ1. H NMR (400 MHz, CDCl3):
δ ϭ 7.78 (d, J ϭ 8.8 Hz, 2 H, 2Ј-,6Ј-H), 7.75 (d, J ϭ 8.8 Hz, 2 H,
2-,6-H), 7.03 (d, J ϭ 8.8 Hz, 2 H, 3Ј-,5Ј-H), 6.94 (d, J ϭ 8.6 Hz, 4
H, 3-,5-H), 6.34 (s, 2 H, 2ЈЈ-,6ЈЈ-H), 3.86 (s, 3 H, OCH3), 3.81 (s, 6
H, OCH3) ppm. 13C NMR (100 MHz, CDCl3): δ ϭ 195.2 (CO),
161.5 (C-4), 160.6 (C-4Ј), 154.0 (C-3ЈЈ, C-5ЈЈ), 151.5 (C-1ЈЈ), 134.8
(C-1Ј), 132.7 (C-2, C-6Ј), 132.3 (C-2Ј, C-6Ј), 129.7 (C-1), 116.7 (C-
3Ј, C-5Ј), 115.3 (C-3, C-5), 97.9 (C-2ЈЈ, C-6ЈЈ), 61.0, 56.2 (OCH3)
ppm. MS (EI): m/z (%) ϭ 380 (100) [Mϩ], 365 (80), 337 (6), 190
(3), 149 (3), 121 (24), 93 (4). C22H20O6 (380.39): calcd. C 69.45, H
5.30; found C 69.57, H 5.36.
Figure 3. Possible arrangements of tetraphenylethenes 1f, 9c (a) and
phenanthrenes 22a,b (b) in the hexagonal columnar mesophase
In conclusion, the scope of the novel tetraphenylethene
mesogenic subunit has been extended to ether and biphenyl
substituents. The pendant trialkoxybenzene groups seem to
play a major role in stabilizing the columnar mesophase. In
addition ether and ester tetraphenylethenes, such as 9c, 1f
can undergo oxidative photocyclization to phenanthrenes
22a,b. Particularly, phenanthrene 22b provides a novel me-
sogenic core unit.
4,4Ј-Bis(3,4,5-trimethoxyphenyloxy)benzophenone (6): M.p. 125 °C.
1
IR (KBr): ν˜ ϭ 1636 cmϪ1. H NMR (400 MHz, CDCl3): δ ϭ 7.79
(d, J ϭ 8.8 Hz, 4 H, 2-,6-H), 7.02 (d, J ϭ 8.8 Hz, 4 H, 3-,5-H),
6.34 (s, 4 H, 2Ј-,6Ј-H), 3.84 (s, 6 H, OCH3), 3.81 (s, 12 H, OCH3)
ppm. 13C NMR (100 MHz, CDCl3): δ ϭ 194.1 (CO), 161.6 (C-4),
154.1 (C-3Ј, C-5Ј), 151.4 (C-1Ј), 135.0 (C-1), 132.2 (C-2, C-6), 132.0
(C-4Ј), 116.7 (C-3, C-5), 97.9 (C-2Ј, C-6Ј), 61.0, 56.1 (OCH3) ppm.
MS (EI): m/z (%) ϭ 546 (100) [Mϩ], 531 (44), 503 (2), 473 (3), 394
(20), 379 (15), 351 (1), 287 (1), 279 (4), 258 (6), 230 (2), 167 (4),
149 (10), 135 (3), 83 (4). C31H30O9 (546.57): calcd. C 68.11, H 5.54;
found C 67.58, H 5.54.
Experimental Section
General: For general experimental conditions and preparation of
1f see ref.[7] Tetraphenylethene (14) (98% pure) was purchased from
Aldrich. The X-ray patterns were recorded by a Guinier film cam-
era which is equipped with a heating stage. The wavelength of the
Cu-Kα line has been used. The exposure time was about 2 h.
4,4Ј-Bis(3,4,5-trihydroxyphenyloxy)benzophenone (7): To a solution
of 6 (1.00 g, 1.83 mmol) in CH2Cl2 (20 mL) at Ϫ60 °C was added
dropwise BBr3 (12.8 mL, 12.8 mmol, 1.0  solution in CH2Cl2),
and the resulting solution was stirred for 1 h at Ϫ60 °C and ad-
ditional 16 h at room temp. The mixture was hydrolyzed under ice-
1-Bromo-3,4,5-trimethoxybenzene (3): To an ice-cooled suspension
of 3,4,5-trimethoxyaniline (2) (18.3 g, 0.10 mol) in H2O (80 mL) cooling by dropwise addition of H2O (40 mL) and CH2Cl2 (20 mL).
and concd. H2SO4 (10 mL) was added dropwise a solution of
NaNO2 (6.90 g, 0.10 mol) in H2O (120 mL) while keeping the tem-
perature at 5Ϫ10 °C. The precipitate was dissolved by addition of
The precipitate was isolated and dissolved in ethyl acetate
(100 mL). The organic layer was washed with 2  HCl (100 mL)
and H2O (100 mL), dried (MgSO4), and the solvents evaporated.
ice-cold H2O (150 mL). The resulting solution was added dropwise After recrystallization from ethyl acetate/CH2Cl2 0.60 g (71%) of a
over 30 min to a refluxing aqueous solution of CuBr (prepared by
refluxing a mixture of CuSO4 (9.99 g, 0.04 mol), copper shavings
pale red solid was isolated, m.p. 212 °C. IR (KBr): ν˜ ϭ 3395, 3388,
1
3315, 1626 cmϪ1. H NMR [400 MHz, (CD3)2CO]: δ ϭ 8.13 (s, 4
2834
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Eur. J. Org. Chem. 2003, 2829Ϫ2839

Tetraphenylethene-Derived Columnar Liquid Crystals
FULL PAPER
H, 3Ј-,5Ј-OH), 7.78 (d, J ϭ 8.8 Hz, 4 H, 2-,6-H), 7.30 (s, 2 H, 4Ј-
4,4Ј-Bis(3,4,5-trisundecyloxyphenyloxy)benzophenone (8d): Flash
OH), 7.04 (d, J ϭ 8.8 Hz, 4 H, 3-,5-H), 6.21 (s, 4 H, 2Ј-,6Ј-H) ppm. chromatography (hexanes/ethyl acetate, 30:1) yielded 1.34 g (89%)
13C NMR [100 MHz, (CD3)2CO]: δ ϭ 194.0 (CO), 163.1 (C-4), of a colorless solid; m.p. 44 °C. IR (KBr): ν˜ ϭ 1654 cmϪ1 1H
148.7 (C-1Ј), 147.5 (C-3Ј, C-5Ј), 132.8 (C-2, C-6), 132.7 (C-1), 131.0 NMR (400 MHz, CDCl3): δ ϭ 7.78 (d, J ϭ 8.8 Hz, 4 H, 2-,6-H),
.
(C-4Ј), 117.2 (C-3, C-5), 100.8 (C-2Ј, C-6Ј) ppm. MS (EI): m/z
7.01 (d, J ϭ 8.8 Hz, 4 H, 3-,5-H), 6.30 (s, 4 H, 2Ј-,6Ј-H), 3.94 (t,
J ϭ 6.7 Hz, 4 H, OCH2CH2), 3.90 (t, J ϭ 6.6 Hz, 8 H, OCH2CH2),
(%) ϭ 462 (100) [Mϩ], 338 (70), 322 (4), 284 (2), 256 (2), 245 (37),
231 (14), 216 (6), 171 (3), 126 (13), 121 (36), 93 (5). C25H18O9 1.82Ϫ1.74 (m, 12 H, CH2), 1.50Ϫ1.43 (m, 12 H, CH2), 1.36Ϫ1.21
(462.41): calcd. C 64.92, H 3.93; found C 64.87, H 3.53.
(m, 84 H, CH2), 0.90Ϫ0.85 (m, 18 H, CH2CH3) ppm. 13C NMR
(100 MHz, CDCl3): δ ϭ 194.3 (CO), 161.8 (C-4), 153.9 (C-3Ј, C-
5Ј), 150.9 (C-1Ј), 135.2 (C-1), 132.2 (C-2, C-6), 131.9 (C-4Ј), 116.6
(C-3, C-5), 99.1 (C-2Ј, C-6Ј), 73.6, 69.1 (OCH2CH2), 31.9, 30.3,
29.8, 29.7, 29.6, 29.4, 29.3, 26.9, 26.1, 26.0, 22.7 (CH2), 14.1 (CH3)
ppm. MS (EI): m/z (%) ϭ 1388 (8) [Mϩ], 1234 (1), 1079 (1), 955
(100), 800 (8), 647 (7), 492 (24), 338 (15), 214 (6), 121 (60).
C91H150O9 (1388.19): calcd. C 78.72, H 10.90; found C 78.81, H
11.13.
General Procedure for the Preparation of 4,4Ј-Bis(3,4,5-trialkyloxy-
phenyloxy)benzophenones 8a؊f: A suspension of ketone 7 (0.50 g,
1.08 mmol), alkyl bromide (6.49 mmol), and K2CO3 (1.80 g,
13.0 mmol) in DMF (20 mL) was heated at 80 °C for 44 h. After
cooling to room temp., the mixture was poured onto ice (50 g). The
resulting precipitate was isolated by filtration, washed with H2O,
and redissolved in CH2Cl2 (100 mL). The organic layer was dried
(MgSO4), evaporated, and purified by flash chromatography on
SiO2.
4,4Ј-Bis(3,4,5-tridodecyloxyphenyloxy)benzophenone (8e): Flash
chromatography (hexanes/ethyl acetate, 30:1) yielded 0.93 g (58%)
4,4Ј-Bis(3,4,5-trioctyloxyphenyloxy)benzophenone (8a): Flash chro-
of a colorless solid; m.p. 42 °C. IR (KBr): ν˜ ϭ 1649 cmϪ1 1H
.
matography (hexanes/ethyl acetate, 25:1) yielded 1.02 g (83%) of a
colorless solid; m.p. 37 °C. IR (KBr): ν˜ ϭ 1654 cmϪ1 1H NMR
.
NMR (400 MHz, CDCl3): δ ϭ 7.78 (d, J ϭ 8.8 Hz, 4 H, 2-,6-H),
7.01 (d, J ϭ 8.6 Hz, 4 H, 3-,5-H), 6.30 (s, 4 H, 2Ј-,6Ј-H), 3.94 (t,
J ϭ 6.6 Hz, 4 H, OCH2CH2), 3.90 (t, J ϭ 6.4 Hz, 8 H, OCH2CH2),
1.82Ϫ1.72 (m, 12 H, CH2), 1.50Ϫ1.41 (m, 12 H, CH2), 1.36Ϫ1.21
(m, 96 H, CH2), 0.89Ϫ0.86 (m, 18 H, CH2CH3) ppm. 13C NMR
(100 MHz, CDCl3): δ ϭ 194.3 (CO), 161.8 (C-4), 153.9 (C-3Ј, C-
5Ј), 150.9 (C-1Ј), 135.2 (C-1), 132.2 (C-2, C-6), 131.9 (C-4Ј), 116.6
(C-3, C-5), 99.1 (C-2Ј, C-6Ј), 73.6, 69.1 (OCH2CH2), 31.9, 30.3,
29.8, 29.7, 29.6, 29.4, 29.3, 26.1, 26.0, 22.7 (CH2), 14.1 (CH3) ppm.
MS (FAB): m/z (%) ϭ 1472 (4) [Mϩ], 1011 (1), 749 (1), 461 (2),
421 (4), 329 (14), 307 (18), 176 (46), 154 (100). C97H162O9
(1472.35): calcd. C 79.12, H 11.10; found C 79.11, H 11.24.
(400 MHz, CDCl3): δ ϭ 7.78 (d, J ϭ 8.6 Hz, 4 H, 2-,6-H), 7.01 (d,
J ϭ 8.8 Hz, 4 H, 3-,5-H), 6.30 (s, 4 H, 2Ј-,6Ј-H), 3.95 (t, J ϭ 6.6 Hz,
4 H, OCH2CH2), 3.90 (t, J ϭ 6.6 Hz, 8 H, OCH2CH2), 1.82Ϫ1.72
(m, 12 H, CH2), 1.52Ϫ1.42 (m, 12 H, CH2), 1.36Ϫ1.23 (m, 48 H,
CH2), 0.90Ϫ0.84 (m, 18 H, CH2CH3) ppm. 13C NMR (100 MHz,
CDCl3): δ ϭ 194.3 (CO), 161.8 (C-4), 153.9 (C-3Ј, C-5Ј), 150.9 (C-
1Ј), 135.2 (C-1), 132.2 (C-2, C-6), 131.9 (C-4Ј), 116.6 (C-3, C-5),
99.1 (C-2Ј, C-6Ј), 73.5, 69.1 (OCH2CH2), 31.9, 31.8, 30.3, 29.5,
29.4, 29.3, 29.2, 26.9, 26.1, 26.0, 22.7, 22.6 (CH2), 14.1 (CH3) ppm.
MS (EI): m/z (%) ϭ 1135 (6) [Mϩ], 787 (100), 674 (34), 562 (5),
461 (3), 449 (26), 338 (12), 309 (3), 149 (3), 121 (38). C73H114O9
(1135.70): calcd. C 77.19, H 10.12; found C 77.04, H 10.24.
4,4Ј-Bis(3,4,5-trihexadecyloxyphenyloxy)benzophenone (8f): Flash
4,4Ј-Bis(3,4,5-trinonyloxyphenyloxy)benzophenone (8b): Flash chro-
chromatography (hexanes/ethyl acetate, 30:1) yielded 1.03 g (65%)
of a colorless solid; m.p. 44 °C. IR (KBr): ν˜ ϭ 1653 cmϪ1 1H
.
matography (hexanes/ethyl acetate, 30:1) yielded 1.36 g (73%) of a
colorless solid; m.p. 33 °C. IR (KBr): ν˜ ϭ 1654 cmϪ1 1H NMR
.
NMR (400 MHz, CDCl3): δ ϭ 7.78 (d, J ϭ 8.8 Hz, 4 H, 2-,6-H),
7.01 (d, J ϭ 8.6 Hz, 4 H, 3-,5-H), 6.30 (s, 4 H, 2Ј-,6Ј-H), 3.94 (t,
J ϭ 6.6 Hz, 4 H, OCH2CH2), 3.90 (t, J ϭ 6.4 Hz, 8 H, OCH2CH2),
1.80Ϫ1.74 (m, 12 H, CH2), 1.49Ϫ1.43 (m, 12 H, CH2), 1.37Ϫ1.22
(m, 144 H, CH2), 0.89Ϫ0.86 (m, 18 H, CH2CH3) ppm. 13C NMR
(100 MHz, CDCl3): δ ϭ 194.3 (CO), 161.8 (C-4), 153.9 (C-3Ј, C-
5Ј), 150.9 (C-1Ј), 135.2 (C-1), 132.2 (C-2, C-6), 131.9 (C-4Ј), 116.6
(C-3, C-5), 99.1 (C-2Ј, C-6Ј), 73.6, 69.2 (OCH2CH2), 31.9, 30.3,
29.8, 29.7, 29.6, 29.4, 29.3, 26.2, 26.1, 22.7 (CH2), 14.1 (CH3) ppm.
MS (EI): m/z (%) ϭ 1807 (1) [Mϩ], 1583 (0.1), 1359 (0.1), 1235
(11), 1011 (3), 788 (1), 561 (3), 335 (7), 285 (4), 169 (23), 83 (48),
58 (100). C121H210O9 (1808.99): calcd. C 80.33, H 11.71; found C
80.49, H 11.92.
(400 MHz, CDCl3): δ ϭ 7.78 (d, J ϭ 8.8 Hz, 4 H, 2-,6-H), 7.01 (d,
J ϭ 8.8 Hz, 4 H, 3-,5-H), 6.30 (s, 4 H, 2Ј-,6Ј-H), 3.95 (t, J ϭ 6.6 Hz,
4 H, OCH2CH2), 3.90 (t, J ϭ 6.6 Hz, 8 H, OCH2CH2), 1.82Ϫ1.72
(m, 12 H, CH2), 1.51Ϫ1.42 (m, 12 H, CH2), 1.37Ϫ1.21 (m, 60 H,
CH2), 0.90Ϫ0.86 (m, 18 H, CH2CH3) ppm. 13C NMR (100 MHz,
CDCl3): δ ϭ 194.2 (CO), 161.8 (C-4), 153.9 (C-3Ј, C-5Ј), 150.8 (C-
1Ј), 135.2 (C-1), 132.2 (C-2, C-6), 131.9 (C-4Ј), 116.5 (C-3, C-5),
99.1 (C-2Ј, C-6Ј), 73.5, 69.1 (OCH2CH2), 31.9, 30.3, 29.7, 29.6,
29.4, 29.3, 26.9, 26.1, 26.0, 22.7 (CH2), 14.1 (CH3) ppm. MS (EI):
m/z (%) ϭ 1219 (1) [Mϩ], 843 (100), 717 (24), 467 (21), 341 (20),
214 (39), 121 (50). C79H126O9 (1219.86): calcd. C 77.77, H 10.42;
found C 77.63, H 10.60.
4,4Ј-Bis(3,4,5-trisdecyloxyphenyloxy)benzophenone (8c): Flash chro-
General Procedure for the Preparation of Tetrakis[4-(3,4,5-trialkyl-
matography (hexanes/ethyl acetate, 30:1) yielded 0.68 g (48%) of a
oxyphenyloxy)phenyl]ethenes 9a؊f: To
a solution of TiCl4
colorless solid; m.p. 50 °C. IR (KBr): ν˜ ϭ 1653 cmϪ1 1H NMR
.
(0.50 mL, 0.50 mmol, 1.0  solution in CH2Cl2) in THF (3.5 mL)
were successively added Zn powder (65.4 mg, 1.00 mmol), pyridine
(31 µL, 0.38 µmol), and a solution of benzophenone 8 (0.44 mmol)
in CH2Cl2 (2 mL). The resulting mixture was stirred at 60 °C for
20 h. Then were added K2CO3 (10 mL, 10% aqueous solution) and
10 mL H2O and the aqueous layer was extracted with CH2Cl2 (3
ϫ 50 mL). The combined organic layers were dried (MgSO4) and
the solvent was removed in vacuo. The crude products were puri-
fied by flash chromatography on SiO2 (hexanes/ethyl acetate, 30:1).
(400 MHz, CDCl3): δ ϭ 7.78 (d, J ϭ 8.8 Hz, 4 H, 2-,6-H), 7.01 (d,
J ϭ 8.8 Hz, 4 H, 3-,5-H), 6.30 (s, 4 H, 2Ј-,6Ј-H), 3.95 (t, J ϭ 6.7 Hz,
4 H, OCH2CH2), 3.90 (t, J ϭ 6.4 Hz, 8 H, OCH2CH2), 1.82Ϫ1.74
(m, 12 H, CH2), 1.49Ϫ1.41 (m, 12 H, CH2), 1.38Ϫ1.23 (m, 72 H,
CH2), 0.89Ϫ0.86 (m, 18 H, CH2CH3) ppm. 13C NMR (100 MHz,
CDCl3): δ ϭ 194.3 (CO), 161.8 (C-4), 153.9 (C-3Ј, C-5Ј), 150.9 (C-
1Ј), 135.2 (C-1), 132.2 (C-2, C-6), 131.9 (C-4Ј), 116.6 (C-3, C-5),
99.1 (C-2Ј, C-6Ј), 73.6, 69.2 (OCH2CH2), 31.9, 30.3, 29.7, 29.6,
29.4, 29.3, 26.1, 26.0, 22.7 (CH2), 14.1 (CH3) ppm. MS (EI): m/z
(%) ϭ 1305 (10) [Mϩ], 899 (100), 759 (8), 517 (12), 277 (5), 206 (7), Tetrakis[4-(3,4,5-trioctyloxyphenyloxy)phenyl]ethene (9a): 0.27 g
121 (6), 73 (40). C85H138O9 (1304.02): calcd. C 78.28, H 10.67;
found C 77.65, H 10.74.
(0.12 mmol, 55%) of a pale yellow solidifying oil, m.p. 54 °C. IR
(KBr): ν˜ ϭ 1593, 1495 cmϪ1. UV: λmax (εmax) ϭ 362 (1.05), 330
Eur. J. Org. Chem. 2003, 2829Ϫ2839
www.eurjoc.org
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2835

A. Schultz, S. Laschat, S. Diele, M. Nimtz
FULL PAPER
(1.99), 296 (2.27), 266 (4.56), 208 (19.45) nm (104 L·molϪ1·cmϪ1).
CDCl3): δ ϭ 6.98 (d, J ϭ 8.8 Hz, 8 H, 2-,6-H), 6.73 (d, J ϭ 8.8 Hz,
8 H, 3-,5-H), 6.19 (s, 8 H, 2Ј-,6Ј-H), 3.91Ϫ3.85 (m, 24 H,
1H NMR (400 MHz, CDCl3): δ ϭ 6.99 (d, J ϭ 8.6 Hz, 8 H, 2-,6-
H), 6.73 (d, J ϭ 8.8 Hz, 8 H, 3-,5-H), 6.20 (s, 8 H, 2Ј-,6Ј-H), OCH2CH2), 1.79Ϫ1.72 (m, 24 H, OCH2CH2CH2), 1.49Ϫ1.40 (m,
3.92Ϫ3.85 (m, 24 H, OCH2CH2), 1.79Ϫ1.70 (m, 24 H, CH2), 24 H, CH2), 1.36Ϫ1.23 (m, 192 H, CH2), 0.90Ϫ0.86 (m, 36 H,
1.49Ϫ1.40 (m, 24 H, CH2), 1.36Ϫ1.23 (m, 96 H, CH2), 0.90Ϫ0.86
CH2CH3) ppm. 13C NMR (100 MHz, CDCl3): δ ϭ 156.1 (C-4),
(m, 36 H, CH2CH3) ppm. 13C NMR (100 MHz, CDCl3): δ ϭ 156.1 153.6 (C-3Ј, C-5Ј), 152.4 (C-1Ј), 139.1 (CϭC), 138.4 (C-1), 134.3
(C-4), 153.6 (C-3Ј, C-5Ј), 152.3 (C-1Ј), 139.1 (CϭC), 138.4 (C-1), (C-4Ј), 132.6 (C-2, C-6), 117.3 (C-3, C-5), 98.1 (C-2Ј, C-6Ј), 73.5,
134.4 (C-4Ј), 132.6 (C-2, C-6), 117.3 (C-3, C-5), 98.1 (C-2Ј, C-6Ј), 69.1 (OCH2CH2), 31.9, 30.3, 29.7, 29.5, 29.4, 29.3, 26.1, 22.7
73.5, 69.1 (OCH2CH2), 31.9, 31.8, 30.3, 29.6, 29.4, 29.3, 26.1, 22.7
(CH2), 14.1 (CH3) ppm. MS (MALDI-TOF): m/z ϭ 2910.3 [Mϩ],
(CH2), 14.1 (CH3) ppm. MS (MALDI-TOF): m/z ϭ 2237.7 [Mϩ], 2933.3 [Mϩ ϩ Na]. C194H324O16 (2912.70): calcd. C 79.99, H 11.22;
2260.7 [Mϩ ϩ Na]. C146H228O16 (2239.41): calcd. C 78.29, H 10.27;
found C 79.67, H 11.35.
found C 78.42, H 10.56.
Tetrakis[4-(3,4,5-trihexadecyloxyphenyloxy)phenyl]ethene
(9f):
0.48 g (0.13 mmol, 61%) of a pale yellow solid. IR (KBr): ν˜ ϭ 1594,
Tetrakis[4-(3,4,5-trinonyloxyphenyloxy)phenyl]ethene (9b): 0.30 g
(0.12 mmol, 57%) of a pale yellow solidifying oil, m.p. 43 °C. IR
(KBr): ν˜ ϭ 1593, 1495 cmϪ1. UV: λmax (εmax) ϭ 330 (1.84), 300
(1.98), 266 (4.52), 208 (20.35) nm (104 L·molϪ1·cmϪ1). 1H NMR
(400 MHz, CDCl3): δ ϭ 6.98 (d, J ϭ 8.6 Hz, 8 H, 2-,6-H), 6.73 (d,
J ϭ 8.8 Hz, 8 H, 3-,5-H), 6.19 (s, 8 H, 2Ј-,6Ј-H), 3.91Ϫ3.85 (m, 24
H, OCH2CH2), 1.79Ϫ1.70 (m, 24 H, OCH2CH2CH2), 1.48Ϫ1.40
(m, 24 H, CH2), 1.37Ϫ1.21 (m, 120 H, CH2), 0.90Ϫ0.86 (m, 36 H,
CH2CH3) ppm. 13C NMR (100 MHz, CDCl3): δ ϭ 156.1 (C-4),
153.6 (C-3Ј, C-5Ј), 152.3 (C-1Ј), 139.1 (CϭC), 138.4 (C-1), 134.4
(C-4Ј), 132.6 (C-2, C-6), 117.3 (C-3, C-5), 98.1 (C-2Ј, C-6Ј), 73.5,
69.1 (OCH2CH2), 31.9, 30.3, 29.7, 29.6, 29.4, 29.3, 26.2, 26.1, 22.7
(CH2), 14.1 (CH3) ppm. MS (MALDI-TOF): m/z ϭ 2405.9 [Mϩ],
2427.9 [Mϩ ϩ Na], 2467.9 [Mϩ ϩ Na ϩ K]. C158H252O16 (2407.73):
calcd. C 78.81, H 10.56; found C 78.93, H 10.86.
1496 cmϪ1. UV: λmax (εmax) ϭ 328 (1.35), 290 (2.18), 264 (3.89),
1
208 (19.50) nm (104 L·molϪ1·cmϪ1). H NMR (400 MHz, CDCl3):
δ ϭ 6.98 (d, J ϭ 8.6 Hz, 8 H, 2-,6-H), 6.73 (d, J ϭ 8.8 Hz, 8 H,
3-,5-H), 6.19 (s, 8 H, 2Ј-,6Ј-H), 3.91Ϫ3.85 (m, 24 H, OCH2CH2),
1.77Ϫ1.72 (m, 24 H, CH2), 1.47Ϫ1.41 (m, 24 H, CH2), 1.37Ϫ1.20
(m, 288 H, CH2), 0.90Ϫ0.86 (m, 36 H, CH2CH3) ppm. 13C NMR
(100 MHz, CDCl3): δ ϭ 156.1 (C-4), 153.6 (C-3Ј, C-5Ј), 152.4 (C-
1Ј), 139.1 (CϭC), 138.4 (C-1), 134.3 (C-4Ј), 132.6 (C-2, C-6), 117.4
(C-3, C-5), 98.1 (C-2Ј, C-6Ј), 73.5, 69.1 (OCH2CH2), 31.9, 30.4,
29.8, 29.7, 29.5, 29.4, 29.3, 26.2, 26.1, 22.7 (CH2), 14.1 (CH3) ppm.
MS (MALDI-TOF): m/z ϭ 3583.1 [Mϩ], 3607.2 [Mϩ ϩ Na].
C242H420O16 (3585.99): calcd. C 81.04, H 11.81; found C 81.10,
H 11.97.
4-Cyanophenylboronic Acid (11): To a cooled solution of 4-bromo-
benzonitrile (10) (9.10 g, 0.05 mol) in THF (150 mL) was added
dropwise at Ϫ78 °C nBuLi (20 mL, 0.05 mol, 2.5  solution in n-
hexane) and the solution was stirred for 1 h at Ϫ78 °C. Then was
added dropwise B(OMe)3 (5.70 mL, 0.05 mol) at Ϫ78 °C. The cool-
ing bath was removed and the mixture was stirred for 20 h at room
temp. After hydrolysis with 10% HCl (150 mL), the layers were
separated and the aqueous layer was extracted with ethyl acetate
(2 ϫ 150 mL). The combined organic layers were washed with H2O
(250 mL), dried (MgSO4), and the solvents evaporated. The residue
was washed with hot hexanes (30 mL) and recrystallized from H2O
(300 mL) to give 2.75 g (37%) of a colorless solid, m.p. 280 °C
(dec.). 1H NMR (200 MHz, CD3COCD3): δ ϭ 7.90 (d, J ϭ 7.8 Hz,
2 H, 3-,5-H), 7.62 (d, J ϭ 8.0 Hz, 2 H, 2-,6-H), 7.42 (s, 2 H, OH)
ppm. 13C NMR (50 MHz, CD3COCD3): δ ϭ 135.4, 131.7 (C-2, C-
3, C-5, C-6), 119.4, 114.3 (C-1, C-6, CN) ppm. MS (EI): m/z (%) ϭ
147 (46), 146 (10) [Mϩ], 130 (3), 120 (1), 103 (100), 102 (6), 76 (14),
75 (4).
Tetrakis[4-(3,4,5-trisdecyloxyphenyloxy)phenyl]ethene (9c): 0.24 g
(0.09 mmol, 49%) of a pale yellow oil, m.p. 38 °C. IR (KBr): ν˜ ϭ
1593, 1495 cmϪ1. UV: λmax (εmax) ϭ 354 (1.16), 330 (1.67), 278
(3.63), 266 (4.24), 208 (19.66) nm (104 L·molϪ1·cmϪ1). 1H NMR
(400 MHz, CDCl3): δ ϭ 6.98 (d, J ϭ 8.6 Hz, 8 H, 2-,6-H), 6.73 (d,
J ϭ 8.8 Hz, 8 H, 3-,5-H), 6.19 (s, 8 H, 2Ј-,6Ј-H), 3.91Ϫ3.85 (m, 24
H, OCH2CH2), 1.79Ϫ1.70 (m, 24 H, OCH2CH2CH2), 1.50Ϫ1.39
(m, 24 H, CH2), 1.37Ϫ1.21 (m, 144 H, CH2), 0.90Ϫ0.86 (m, 36 H,
CH2CH3) ppm. 13C NMR (100 MHz, CDCl3): δ ϭ 156.1 (C-4),
153.6 (C-3Ј, C-5Ј), 152.3 (C-1Ј), 139.1 (CϭC), 138.4 (C-1), 134.4
(C-4Ј), 132.6 (C-2, C-6), 117.3 (C-3, C-5), 98.1 (C-2Ј, C-6Ј), 73.5,
69.1 (OCH2CH2), 31.9, 30.3, 29.8, 29.7, 29.6, 29.4, 29.3, 26.2, 26.1,
22.7 (CH2), 14.1 (CH3) ppm. MS (MALDI-TOF): m/z ϭ 2574.1
[Mϩ], 2597.1 [Mϩ ϩ Na]. C170H276O16 (2576.05): calcd. C 79.25,
H 10.81; found C 79.00, H 11.02.
Tetrakis[4-(3,4,5-trisundecyloxyphenyloxy)phenyl]ethene (9d): 0.31 g
(0.11 mmol, 51%) of a pale yellow solid. IR (KBr): ν˜ ϭ 1593, 1495
cmϪ1. UV: λmax (εmax) ϭ 328 (1.64), 300 (1.86), 264 (4.17), 208
(18.70) nm (104 L·molϪ1·cmϪ1). 1H NMR (400 MHz, CDCl3): δ ϭ
6.98 (d, J ϭ 8.8 Hz, 8 H, 2-,6-H), 6.73 (d, J ϭ 8.8 Hz, 8 H, 3-,5-
H), 6.19 (s, 8 H, 2Ј-,6Ј-H), 3.91Ϫ3.85 (m, 24 H, OCH2CH2),
1.79Ϫ1.70 (m, 24 H, CH2), 1.49Ϫ1.40 (m, 24 H, CH2), 1.36Ϫ1.20
(m, 168 H, CH2), 0.89Ϫ0.86 (m, 36 H, CH2CH3) ppm. 13C NMR
(100 MHz, CDCl3): δ ϭ 156.1 (C-4), 153.6 (C-3Ј, C-5Ј), 152.3 (C-
1Ј), 139.1 (CϭC), 138.4 (C-1), 134.3 (C-4Ј), 132.6 (C-2, C-6), 117.4
(C-3, C-5), 98.1 (C-2Ј, C-6Ј), 73.5, 69.1 (OCH2CH2), 31.9, 30.3,
29.7, 29.5, 29.4, 29.3, 26.2, 26.1, 22.7 (CH2), 14.1 (CH3) ppm. MS
3,4,5-Trimethoxyphenylboronic Acid (12): To a cooled solution of 3
(4.94 g, 0.02 mol) in THF (50 mL) was added dropwise at Ϫ85 °C
nBuLi (8.00 mL, 0.02 mol, 2.5  solution in n-hexane) and the
solution was stirred for 1 h at Ϫ85 °C. Then was added dropwise
B(OMe)3 (2.30 mL, 0.02 mol) at Ϫ85 °C. The cooling bath was
removed and the mixture was stirred for 18 h at room temp. After
hydrolysis with 10% HCl (150 mL), the layers were separated and
the aqueous layer was extracted with ethyl acetate (2 ϫ 120 mL).
The combined organic layers were washed with H2O (150 mL),
dried (MgSO4), and concentrated to a volume of 30 mL. Precipi-
tation was completed by addition of n-hexane (50 mL). After fil-
tration, 2.73 g (64%) of a colorless solid were isolated, m.p. 247 °C.
(MALDI-TOF): m/z
ϭ ϩ Na].
2742.2 [Mϩ], 2765.2 [Mϩ
C182H300O16 (2744.37): calcd. C 79.64, H 11.03; found C 79.64,
H 11.31.
1
IR (KBr): ν˜ ϭ 3448, 3373, 1585, 1510 cmϪ1. H NMR (400 MHz,
CD3COCD3): δ ϭ 7.19 (s, 2 H, 2-,6-H), 7.14 (s, 2 H, OH), 3.82
(s, 6 H, OCH3), 3.74 (s, 3 H, OCH3) ppm. 13C NMR (100 MHz,
CD3COCD3): δ ϭ 153.9, 141.4 (C-1, C-3, C-4, C-5), 112.1 (C-2,
Tetrakis[4-(3,4,5-tridodecyloxyphenyloxy)phenyl]ethene (9e): 0.22 g
(0.08 mmol, 34%) of a pale yellow solid. IR (KBr): ν˜ ϭ 1592, 1498
cmϪ1. UV: λmax (εmax) ϭ 358 (0.47), 330 (1.80), 286 (2.90), 266 C-6), 60.4 (4-OCH3), 56.3 (OCH3) ppm. MS (EI): m/z (%) ϭ 582
(4.23), 208 (18.62) nm (104 L·molϪ1·cmϪ1). 1H NMR (400 MHz,
(100), 581 (63), 580 (16), 334 (34), 319 (23), 291 (8), 212 (63) [Mϩ],
2836
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
Eur. J. Org. Chem. 2003, 2829Ϫ2839

Tetraphenylethene-Derived Columnar Liquid Crystals
FULL PAPER
197 (36), 168 (50), 153 (30), 110 (14), 86 (15). C9H13BO5 (212.01):
calcd. C 50.99, H 6.18, B 5.10; found C 51.42, H 6.37, B 5.30.
Tetrakis[4-(3,4,5-trihydroxyphenyl)phenyl]ethene (17): To a cooled
solution of 16 (300 mg, 0.30 mmol) in CH2Cl2 (20 mL) was added
dropwise at Ϫ78 °C BBr3 (4.20 mL, 4.20 mmol, 1.0  solution in
CH2Cl2), and the resulting mixture was stirred for 1 h at Ϫ78 °C
and 40 h at room temp. Then H2O (2 ϫ 10 mL) and CH2Cl2
(10 mL) were added dropwise under ice-cooling and the precipitate
was isolated, washed with a minimum amount of H2O and CH2Cl2
and redissolved in ethyl acetate (100 mL). The layers were sepa-
rated and the organic layer was washed with 2  HCl (100 mL)
and H2O (100 mL), dried (MgSO4), and the solvents evaporated.
Recrystallization from ethyl acetate/CH2Cl2 yielded 230 mg (92%)
of a yellow solid, m.p. 353 °C (dec.). IR (KBr): ν˜ ϭ 3417, 1613,
1542, 1505 cmϪ1. UV: λmax (εmax) ϭ 396 (0.64), 350 (2.53), 306
(5.43), 210 (10.31), 194 (9.31) nm (104 L·molϪ1·cmϪ1). 1H NMR
(400 MHz, CD3OD): δ ϭ 7.30 (d, J ϭ 8.5 Hz, 8 H, 3-,5-H), 7.07
(d, J ϭ 8.5 Hz, 8 H, 2-,6-H), 6.59 (s, 8 H, 2Ј-,6Ј-H) ppm. 13C NMR
(100 MHz, CD3OD): δ ϭ 147.2 (C-3Ј, C-5Ј), 141.5 (CϭC), 143.6,
140.6, 134.1, 133.1 (C1, C1Ј, C-4, C-4Ј), 132.9 (C-3, C-5), 126.6 (C-
2, C-6), 106.8 (C-2Ј, C-6Ј) ppm. MS (EI): m/z (%) ϭ 828 (3) [Mϩ],
812 (1), 416 (100), 400 (7), 215 (44), 185 (14), 81 (14). C50H36O12
(828.83): calcd. C 72.44, H 4.38; found C 73.31, H 4.52.
Tetrakis[4-(4Ј-cyanophenyl)phenyl]ethene (13): To a solution of 15
(320 mg, 0.50 mmol) in degassed DME (20 mL) were added
sequentially a solution of 2  Na2CO3 (20 mL, in degassed H2O),
Pd(PPh3)4 (87 mg, 75.0 µmol), and 11 (440 mg, 3.00 mmol), and
the resulting mixture was heated at 100 °C for 18 h. After cooling
to room temp., H2O (100 mL) was added and the aqueous layer
was extracted with Et2O (3 ϫ 100 mL) and CH2Cl2 (3 ϫ 100 mL).
The CH2Cl2 layer was dried (MgSO4), evaporated, and the residue
was purified by flash chromatography on SiO2 (hexanes/ethyl acet-
ate, 2:1; then CH2Cl2) to give 230 mg (62%) of a pale yellow solid,
m.p. 337 °C (dec.). IR (KBr): ν˜ ϭ 2225, 1606, 1573, 1492 cmϪ1
.
UV: λmax (εmax) ϭ 404 (0.53), 370 (2.39), 352 (3.43), 326 (5.27),
314 (5.82), 286 (6.13), 272 (5.52), 202 (13.02) nm (104
L·molϪ1·cmϪ1). 1H NMR (400 MHz, CDCl3): δ ϭ 7.69 (d, J ϭ
8.6 Hz, 8 H, 2Ј-,6Ј-H), 7.65 (d, J ϭ 8.6 Hz, 8 H, 3Ј-,5Ј-H), 7.42 (d,
J ϭ 8.6 Hz, 8 H, 2-,6-H), 7.22 (d, J ϭ 8.6 Hz, 8 H, 3-,5-H) ppm.
13C NMR (100 MHz, CDCl3): δ ϭ 144.7, 143.6, 137.4 (C-1, C-4,
C-1Ј), 140.7 (CϭC), 132.6 (C-3Ј, C-5Ј), 132.1 (C-3, C-5), 127.4 (C-
2Ј, C-6Ј), 126.7 (C-2, C-6), 118.8 (CN), 110.9 (C-4Ј) ppm. MS (EI):
m/z (%) ϭ 736 (14) [Mϩ], 635 (100). C54H32N4 (736.87): calcd. C
88.01, H 4.38, N 7.61; found C 88.02, H 4.41, N 7.24.
Tetrakis[4-(3,4,5-tridodecyloxyphenyl)phenyl]ethene (18b): A sus-
pension of K2CO3 (0.83 g, 6.00 mmol), 17 (0.20 g, 0.24 mmol), and
dodecyl bromide (0.72 g, 2.90 mmol) in DMF (20 mL) was heated
at 80 °C for 3 days. After cooling to room temp., H2O (20 mL) was
added. The aqueous layer was extracted with CH2Cl2 (2 ϫ 100 mL)
and the combined organic layers were washed with H2O (2 ϫ
100 mL), dried (MgSO4), and azeotropically codistilled with tolu-
ene (4 ϫ 30 mL). After flash chromatography on SiO2 (hexanes/
ethyl acetate, 30:1), the crude product was dissolved in CH2Cl2
(2 mL), then EtOH (50 mL) was added. The resulting yellow solid-
ifying oil was isolated after decanting the solvent. Yield: 46 mg
(7%). IR (KBr): ν˜ ϭ 1586, 1498 cmϪ1. UV: λmax (εmax) ϭ 354
(3.35), 308 (7.29), 210 (14.36) nm (104 L·molϪ1·cmϪ1). 1H NMR
(400 MHz, CDCl3): δ ϭ 7.35 (d, J ϭ 8.3 Hz, 8 H, 3-,5-H), 7.14 (d,
J ϭ 8.3 Hz, 8 H, 2-,6-H), 6.75 (s, 8 H, 2Ј-,6Ј-H), 4.01 (t, J ϭ 6.4 Hz,
16 H, OCH2CH2), 3.97 (t, J ϭ 6.6 Hz, 8 H, OCH2CH2), 1.84Ϫ1.74
(m, 24 H, CH2), 1.51Ϫ1.44 (m, 24 H, CH2), 1.37Ϫ1.22 (m, 192 H,
CH2), 0.90Ϫ0.86 (m, 36 H, CH2CH3) ppm. 13C NMR (100 MHz,
CDCl3): δ ϭ 153.4 (C-3Ј, C-5Ј), 140.2 (CϭC), 142.7, 139.1, 138.0,
135.8 (C-1, C-1Ј, C-4, C-4Ј), 131.8 (C-3, C-5), 126.2 (C-2, C-6),
105.6 (C-2Ј, C-6Ј), 73.5 (OCH2CH2), 69.3 (OCH2CH2), 31.9, 30.4,
29.8, 29.7, 29.5, 29.4, 26.1, 22.7 (CH2), 14.1 (CH3) ppm. MS
(MALDI-TOF): m/z ϭ 2846.5 [Mϩ]. C194H324O12 (2848.70): calcd.
C 81.79, H 11.47; found C 81.71, H 11.55.
Tetrakis(4-bromophenyl)ethene (15): Powdered tetraphenylethene 14
(5.00 g, 15.0 mmol) was treated with bromine (7.50 mL, 0.15 mol)
and the mixture was kept for 16 h at room temp. The resulting solid
was dissolved in hot toluene (120 mL), the solution was concen-
trated to 20 mL and the precipitate was isolated and washed with
hexanes. After flash chromatography on SiO2 (hexanes/CH2Cl2,
20:1), 5.12 g (53%) of a colorless solid was obtained, m.p. 247 °C.
1H NMR (200 MHz, CDCl3): δ ϭ 7.26 (d, J ϭ 8.6 Hz, 8 H, 3-,5-
H), 6.84 (d, J ϭ 8.6 Hz, 8 H, 2-,6-H) ppm. 13C NMR (50 MHz,
CDCl3): δ ϭ 141.4 (C-1), 139.6 (CϭC), 132.7 (C-3, C-5), 131.3 (C-
2, C-6), 121.3 (C-4) ppm. MS (EI): m/z (%) ϭ 652 (12), 650 (58),
648 (94), 646 (66), 644 (14) [Mϩ], 572 (33), 570 (88), 568 (95), 566
(30), 490 (25), 488 (27), 486 (10), 410 (30), 408 (28), 329 (34), 327
(78), 325 (24), 254 (12), 252 (100), 250 (42), 163 (75), 149 (39), 111
(22), 83 (34).
Tetrakis[4-(3,4,5-trimethoxyphenyl)phenyl]ethene (16): To a solution
of 15 (500 mg, 0.77 mmol) in degassed DME (30 mL) were added
sequentially a solution of 2  Na2CO3 (30 mL in degassed H2O),
Pd(PPh3)4 (133 mg, 0.12 mmol), and 12 (0.98 g, 4.63 mmol) and
the resulting mixture was heated at 100 °C for 24 h. After cooling
to room temp., H2O (100 mL) was added and the aqueous layer
was extracted with Et2O (100 mL) and ethyl acetate (2 ϫ 150 mL). 4,4Ј-Bis(3,4,5-trimethoxyphenyl)benzophenone (19): To a solution of
The ethyl acetate layer was washed with H2O (100 mL), dried
(MgSO4), evaporated, and the residue was purified by flash chro-
matography on SiO2 (CH2Cl2/ethyl acetate, 10:1 Ǟ 4:1), recrystalli-
4,4Ј-dibromobenzophenone 4b (950 mg, 2.80 mmol) in degassed
DME (50 mL) were added sequentially a solution of 2  Na2CO3
(50 mL in degassed H2O), Pd(PPh3)4 (240 mg, 0.21 mmol), and 12
zation from CH2Cl2/n-hexane and by flash chromatography on (1.48 g, 7.00 mmol) and the resulting mixture was heated at 100 °C
SiO2 (CH2Cl2/ethyl acetate, 5:1) to give 0.43 g (56%) of a pale yel-
for 60 h. After cooling to room temp., H2O (200 mL) was added
low solid, m.p. 264 °C. IR (KBr): ν˜ ϭ 1586, 1554, 1497 cmϪ1. UV: and the aqueous layer was extracted with CH2Cl2 (2 ϫ 150 mL).
λmax (εmax) ϭ 390 (1.06), 348 (3.38), 302 (7.51), 200 (19.37) nm (104 The combined organic layers were washed with H2O (100 mL),
L·molϪ1·cmϪ1). 1H NMR (400 MHz, CD3COCD3): δ ϭ 7.38 (d, dried (MgSO4), evaporated, and purified by flash chromatography
J ϭ 8.3 Hz, 8 H, 3-,5-H), 7.19 (d, J ϭ 8.3 Hz, 8 H, 2-,6-H), 6.77
(s, 8 H, 2Ј-,6Ј-H), 3.90 (s, 24 H, OCH3), 3.87 (s, 12 H, OCH3) ppm. yellow solid, m.p. 149 °C. IR (KBr): ν˜ ϭ 1656 cmϪ1
13C NMR (100 MHz, CD3COCD3): δ ϭ 153.4 (C-3Ј, C-5Ј), 140.2
(400 MHz, CDCl3): δ ϭ 7.91 (d, J ϭ 8.3 Hz, 4 H, 2-,6-H), 7.68 (d,
on SiO2 (hexanes/ethyl acetate, 1:1) to give 1.47 g (quant.) of a pale
.
1H NMR
(CϭC), 142.8, 139.0, 137.7, 136.4 (C-1, C-1Ј, C-4, C-4Ј), 131.8 (C- J ϭ 8.3 Hz, 4 H, 3-,5-H), 6.84 (s, 4 H, 2Ј-,6Ј-H), 3.95 (s, 12 H,
3, C-5), 126.3 (C-2, C-6), 104.1 (C-2Ј, C-6Ј), 60.9 (OCH3), 56.2 OCH3), 3.91 (s, 6 H, OCH3) ppm. 13C NMR (100 MHz, CDCl3):
(OCH3) ppm. MS (EI): m/z (%) ϭ 997 (100) [Mϩ], 982 (1), 831 (2), δ ϭ 195.7 (CO), 153.6 (C-3Ј, C-5Ј), 145.3 (C-4), 138.4, 135.8 (C-
498 (15), 303 (1), 284 (3), 230 (3), 168 (8), 83 (12). C62H60O12
(997.15): calcd. C 74.67, H 6.07; found C 75.16, H 6.19.
1Ј, C-4Ј), 136.3 (C-1), 130.6 (C-2, C-6), 126.9 (C-3, C-5), 104.6 (C-
2Ј, C-6Ј), 60.9, 56.2 (OCH3) ppm. MS (EI): m/z (%) ϭ 514 (100)
Eur. J. Org. Chem. 2003, 2829Ϫ2839
www.eurjoc.org
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2837

A. Schultz, S. Laschat, S. Diele, M. Nimtz
[Mϩ], 499 (36), 471 (7), 441 (5), 413 (2), 272 (1), 271 (10), 257 (4), (C-4, C-1Ј), 140.2 (CϭC), 138.0 (C-1), 135.8 (C-4Ј), 131.8 (C-2, C-
FULL PAPER
243 (2), 213 (4), 128 (3). C31H30O7 (514.57): calcd. C 72.35, H 5.88;
found C 72.38, H 5.97.
6), 126.1 (C-3, C-5), 105.6 (C-2Ј, C-6Ј), 73.5, 69.3 (OCH2CH2),
31.9, 30.4, 29.7, 29.6, 29.5, 29.4, 29.3, 26.1, 22.7 (CH2), 14.1 (CH3)
ppm. MS (MALDI-TOF): m/z ϭ 2510.3 [Mϩ], 2533.3 [Mϩ ϩ Na].
C170H276O12 (2512.05): calcd. C 81.27, H 11.08; found C 81.11,
H 11.25.
4,4Ј-Bis(3,4,5-trihydroxyphenyl)benzophenone (20): To
a cooled
solution of 19 (1.29 g, 2.50 mmol) in CH2Cl2 (30 mL) was added
dropwise at Ϫ78 °C BBr3 (17.5 mL, 17.5 mmol, 1.0  solution in
CH2Cl2), and the resulting mixture was stirred for 1 h at Ϫ78 °C
3,6-Bis(3,4,5-trisdecyloxyphenyloxy)-9,10-bis[4-(3,4,5-trisdecyloxy-
and 18 h at room temp. Then H2O (2 ϫ 30 mL) and CH2Cl2 phenyloxy)phenyl]phenanthrene (22a): A solution of 9c (100 mg,
(20 mL) were added dropwise under ice-cooling and the precipitate
was isolated and redissolved in ethyl acetate (250 mL). The layers
were separated and the organic layer was washed with 2  HCl
(200 mL) and H2O (200 mL), dried (MgSO4), and the solvents eva-
porated. Recrystallization from acetone/CH2Cl2 gave 0.77 g (72%)
of a pale green solid, m.p. 327 °C. IR (KBr): ν˜ ϭ 3441, 3330, 1635
38.8 µmol) and iodine (9.85 mg, 38.8 µmol) in toluene (15 mL) was
irradiated for 2 days with a daylight lamp. Then the mixture was
washed with sat. Na2SO3 (20 mL) and H2O (20 mL), dried
(MgSO4) and the solvents evaporated. Flash chromatography on
SiO2 (hexanes/ethyl acetate, 30:1) yielded 70 mg (73%) of a color-
less solid. IR (KBr): ν˜ ϭ 1595, 1519, 1494 cmϪ1. UV: λmax (εmax) ϭ
372 (0.37), 354 (0.41), 326 (1.97), 316 (2.84), 294 (4.74), 262 (11.67),
208 (26.94) nm (104 L·molϪ1·cmϪ1). 1H NMR (400 MHz, CDCl3):
cmϪ1 1H NMR [400 MHz, (CD3)2CO]: δ ϭ 8.10 (s, 4 H, 3Ј-,5Ј-
.
OH), 7.84 (d, J ϭ 8.6 Hz, 4 H, 2-,6-H), 7.72 (d, J ϭ 8.6 Hz, 4 H,
3-,5-H), 7.61 (s, 2 H, 4Ј-OH), 6.83 (s, 4 H, 2Ј-,6Ј-H) ppm. 13C NMR δ ϭ 8.20 (d, J ϭ 2.3 Hz, 2 H, 4-,5-H), 7.58 (d, J ϭ 8.8 Hz, 2 H,
[100 MHz, (CD3)2CO]: δ ϭ 195.6 (CO), 147.1 (C-3Ј, C-5Ј), 145.9 1-,8-H), 7.18 (dd, J ϭ 9.1/2.2 Hz, 2 H, 2-,7-H), 7.09 (d, J ϭ 8.6 Hz,
(C-4), 136.7 (C-1Ј), 134.5 (C-1), 131.8 (C-4Ј), 131.2 (C-2, C-6), 4 H, 2ЈЈ-,6ЈЈ-H), 6.88 (d, J ϭ 8.6 Hz, 4 H, 3ЈЈ-,5ЈЈ-H), 6.31 (s, 4 H),
127.0 (C-3, C-5), 107.1 (C-2Ј, C-6Ј) ppm. MS (EI): m/z (%) ϭ 430 6.22 (s, 4 H, 2Ј-,2ЈЈЈ-,6Ј-,6ЈЈЈ-H), 3.96Ϫ3.85 (m, 24 H, OCH2CH2),
(100) [Mϩ ϩ H], 429 (6), 413 (3), 382 (1), 373 (3), 305 (2), 229 (56),
215 (49), 201 (6), 183 (8), 155 (19), 104 (10), 91 (12), 77 (8). (m, 144 H, CH2), 0.90Ϫ0.85 (m, 36 H, CH2CH3) ppm. 13C NMR
1.81Ϫ1.71 (m, 24 H, CH2), 1.49Ϫ1.40 (m, 24 H, CH2), 1.36Ϫ1.22
C25H18O7 (430.41): calcd. C 69.75, H 4.22; found C 69.64, H 4.49.
(100 MHz, CDCl3): δ ϭ 156.2, 156.0 (C-3, C-6, C-4ЈЈ), 153.8, 153.7
(C-3Ј, C-3ЈЈЈ, C-5Ј, C-5ЈЈЈ), 152.7, 152.6 (C-1Ј, C-1ЈЈЈ), 135.4, 134.1
(C-9, C-10, C-1ЈЈ), 134.5, 134.4 (C-4Ј, C-4ЈЈЈ), 132.3 (C-2ЈЈ, C-6ЈЈ),
131.0, 128.3 (C-1a, C-4a, C-8a, C-9a), 129.5 (C-1, C-8), 118.9 (C-
2, C-7), 117.6 (C-3ЈЈ, C-5ЈЈ), 98.0 (C-2Ј, C-2ЈЈЈ, C-6Ј, C-6ЈЈЈ), 73.5,
69.1 (OCH2CH2), 31.9, 30.4, 29.8, 29.7, 29.6, 29.5, 29.4, 29.3, 26.2,
26.1, 22.7 (CH2), 14.1 (CH3) ppm. MS (MALDI-TOF): m/z ϭ
2572.3 [Mϩ], 2595.4 [Mϩ ϩ Na]. C170H274O16 (2574.04): calcd. C
79.31, H 10.74; found C 79.24, H 10.92.
4,4Ј-Bis(3,4,5-trisdecyloxyphenyl)benzophenone (21): A suspension
of K2CO3 (1.93 g, 14.0 mmol), 20 (0.50 g, 1.16 mmol), and decyl
bromide (1.54 g, 7.00 mmol) in DMF (20 mL) was heated at 80 °C
for 4 days. Then the mixture was poured onto ice (50 g), the precipi-
tate was filtered through Celite, washed with H2O and redissolved
in CH2Cl2 (150 mL). The organic layer was dried (MgSO4), evapo-
rated, and purified by flash chromatography on SiO2 (hexanes/ethyl
acetate, 20:1) to give 1.23 g (83%) of a colorless solid. IR (KBr):
ν˜ ϭ 1654 cmϪ1
.
1H NMR (400 MHz, CDCl3): δ ϭ 7.89 (d, J ϭ 3,6-Bis(3,4,5-trisdecyloxybenzoyloxy)-9,10-bis[4-(3,4,5-trisdecyloxy-
8.3 Hz, 4 H, 2-,6-H), 7.67 (d, J ϭ 8.3 Hz, 4 H, 3-,5-H), 6.82 (s, 4 benzoyloxy)phenyl]phenanthrene (22b): A solution of tetraphenyl-
H, 2Ј-,6Ј-H), 4.06 (t, J ϭ 6.4 Hz, 8 H, OCH2CH2), 4.02 (t, J ϭ
6.6 Hz, 4 H, OCH2CH2), 1.88Ϫ1.75 (m, 12 H, CH2), 1.54Ϫ1.47
ethene 1f (500 mg, 0.19 mmol) and iodine (47.2 mg, 0.19 mmol) in
toluene (65 mL) was irradiated for 7 days with a daylight lamp.
(m, 12 H, CH2), 1.36Ϫ1.22 (m, 72 H, CH23), 0.91Ϫ0.87 (m, 18 H, Then the mixture was washed with sat. Na2SO3 (50 mL) and H2O
CH2CH3) ppm. 13C NMR (100 MHz, CDCl3): δ ϭ 195.8 (CO), (50 mL), dried (MgSO4), and the solvents evaporated. Flash chro-
153.5 (C-3Ј, C-5Ј), 145.4 (C-4), 138.8, 135.2 (C-1Ј, C-4Ј), 136.2 (C- matography on SiO2 (hexanes/ethyl acetate, 25:1) and recrystalliza-
1), 130.6 (C-2, C-6), 126.8 (C-3, C-5), 106.2 (C-2Ј, C-6Ј), 73.6, 69.4 tion from CH2Cl2/EtOH yielded 160 mg (31%) of a pale yellow
(OCH2CH2), 31.9, 30.4, 29.7, 29.6, 29.5, 29.4, 29.3, 26.1, 26.0, 22.7 solid. IR (KBr): ν˜ ϭ 1732, 1587, 1501 cmϪ1. UV: λmax (εmax) ϭ
(CH2), 14.1 (CH3) ppm. MS (EI): m/z (%) ϭ 1272 (94), 1271 (100) 358 (0.23), 334 (0.37), 308 (4.11), 278 (9.88), 266 (9.03), 218 (16.48),
[Mϩ], 1131 (11), 991 (10), 851 (5), 709 (12), 569 (8), 429 (16), 401
(3), 285 (1), 229 (3), 111 (1). C85H138O7 (1272.03): calcd. C 80.25,
H 10.94; found C 79.63, H 10.87.
192 (10.85) nm (104 L·molϪ1·cmϪ1). 1H NMR (400 MHz, CDCl3):
δ ϭ 8.51 (d, J ϭ 2.3 Hz, 2 H, 4-,5-H), 7.67 (d, J ϭ 9.1 Hz, 2 H,
1-,8-H), 7.48, 7.43 (s, s, 8 H, 2Ј-H, 2ЈЈЈ-H, 6Ј-H, 6ЈЈЈ-H), 7.38 (dd,
J ϭ 9.1/2.2 Hz, 2 H, 2-,7-H), 7.29 (d, J ϭ 8.3 Hz, 4 H, 2ЈЈ-,6ЈЈ-H),
7.18 (d, J ϭ 8.6 Hz, 4 H, 3ЈЈ-,5ЈЈ-H), 4.09Ϫ4.05 (m, 24 H,
OCH2CH2), 1.87Ϫ1.76 (m, 24 H, CH2), 1.52Ϫ1.47 (m, 24 H, CH2),
1.38Ϫ1.21 (m, 144 H, CH2), 0.91Ϫ0.86 (m, 36 H, CH2CH3) ppm.
13C NMR (100 MHz, CDCl3): δ ϭ 165.3, 165.0 (CO), 153.0 (C-3Ј,
C-3ЈЈЈ, C-5Ј, C-5ЈЈЈ), 149.8 (C-3, C-6, C-4ЈЈ), 143.1, 143.0 (C-4Ј, C-
4ЈЈЈ), 136.7, 136.0 (C-1ЈЈ, C-9, C-10), 132.0 (C-2ЈЈ, C-6ЈЈ), 130.8,
130.1 (C-1a, C-4a, C-8a, C-9a), 129.5 (C-1, C-8), 123.8, 123.7 (C-
1Ј, C-1ЈЈЈ), 121.8 (C-2, C-7), 121.3 (C-3ЈЈ, C-5ЈЈ), 115.1 (C-4, C-5),
108.6, 108.5 (C-2Ј, C-2ЈЈЈ, C-6Ј, C-6ЈЈЈ), 73.6, 69.3 (OCH2CH2),
31.9, 30.4, 29.7, 29.6, 29.4, 29.3, 26.1, 22.7 (CH2), 14.1 (CH3) ppm.
MS (MALDI-TOF): m/z ϭ 2707.1 [Mϩ ϩ Na]. C174H274O20
(2686.08): calcd. C 77.79, H 10.29; found C 77.44, H 10.29.
Tetrakis[4-(3,4,5-trisdecyloxyphenyl)phenyl]ethene (18a): To a solu-
tion of TiCl4 (0.75 mL, 0.75 mmol, 1.0  solution in CH2Cl2) in
THF (3.5 mL) were successively added Zn powder (98.1 mg,
1.50 mmol), pyridine (46.5 µL, 0.57 µmol) and a solution of 21
(0.84 g, 0.66 mmol) in CH2Cl2 (3 mL). The resulting mixture was
stirred at 50 °C for 24 h. Then were added K2CO3 (10 mL, 10%
aqueous solution) and 10 mL H2O and the aqueous layer was ex-
tracted with CH2Cl2 (3 ϫ 50 mL). The combined organic layers
were dried (MgSO4), evaporated, and purified by flash chromatog-
raphy on SiO2 (hexanes/ethyl acetate, 25:1) to give 230 mg (28%)
of a yellow solid. IR (KBr): ν˜ ϭ 1586, 1493 cmϪ1. UV: λmax
(εmax) ϭ 352 (2.28), 300 (6.41), 210 (13.97) nm (104 L·molϪ1·cmϪ1).
1H NMR (400 MHz, CDCl3): δ ϭ 7.35 (d, J ϭ 8.1 Hz, 8 H, 2-,6-
H), 7.14 (d, J ϭ 8.4 Hz, 8 H, 3-,5-H), 6.75 (s, 8 H, 2Ј-,6Ј-H), 4.01
(t, J ϭ 6.4 Hz, 16 H, OCH2CH2), 3.97 (t, J ϭ 6.7 Hz, 8 H,
OCH2CH2), 1.84Ϫ1.74 (m, 24 H, CH2), 1.51Ϫ1.44 (m, 24 H, CH2),
1.38Ϫ1.22 (m, 144 H, CH2), 0.90Ϫ0.86 (m, 36 H, CH2CH3) ppm.
13C NMR (100 MHz, CDCl3): δ ϭ 153.4 (C-3Ј, C-5Ј), 142.7, 139.1
[1] [1a]
A. N. Cammidge, R. J. Bushby, Handbook of Liquid Crys-
tals (Eds.: D. Demus, J. Goodby, G. W. Gray, H.-W. Spiess, V.
Vill), vol. 2B, Wiley-VCH, Weinheim, Gemany, 2000, p.
[1b]
693Ϫ743.
S. Chandrasekhar, Handbook of Liquid Crystals,
2838
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
Eur. J. Org. Chem. 2003, 2829Ϫ2839

Tetraphenylethene-Derived Columnar Liquid Crystals
FULL PAPER
(Eds.: D. Demus, J. Goodby, G. W. Gray, H.-W. Spiess, V. Vill),
vol. 2B, Wiley-VCH, Weinheim, Gemany, 2000, p. 744Ϫ780.
N. Boden, R. J. Bushby, J. Clements, M. V. Jesudason, P. F.
Knowles, G. Williams, Chem. Phys. Lett. 1988, 152, 94Ϫ99.
D. Adam, F. Closs, T. Frey, D. Funhoff, D. Haarer, H. Rings-
dorf, P. Schuhmacher, K. Siemensmeyer, Phys. Rev. Lett. 1993,
709, 457Ϫ460.
N. Boden, B. Movaghar, Handbook of Liquid Crystals, (Eds.:
D. Demus, J. Goodby, G. W. Gray, H.-W. Spiess, V. Vill), vol.
2B, Wiley-VCH, Weinheim, Gemany, 2000, p. 781Ϫ798.
Wood, J. T. Gordon, J. Am. Chem. Soc. 1964, 84, 3094Ϫ3102.
[9n]
F. B. Mallory, C. S. Wood, J. T. Gordon, L. C. Lindquist,
[9o]
[2]
M. L. Savitz, J. Am. Chem. Soc. 1962, 84, 4361Ϫ4362.
E. Buckles, J. Am. Chem. Soc. 1955, 77, 1040Ϫ1041.
Parker, P. E. Spoerri, Nature 1950, 166, 603.
R.
[9p]
C. O.
[3]
[10] [10a] C. E. Bunker, N. B. Hamilton, Y.-P. Sun, Anal. Chem. 1993,
[10b]
65, 3460Ϫ3465.
L. Mussons, C. Raposo, J. Anaya, M.
Grande, J. R. Moran, C. Caballero, J. Chem. Soc., Perkin
[4]
Trans. 1 1992, 3125Ϫ3128. [10c] B. König, A. de Meijere, Chem.
[10d]
Ber. 1992, 125, 1895Ϫ1898.
H.-F. Grützmacher, W. Huse-
[10e]
mann, Tetrahedron Lett. 1985, 26, 2431Ϫ2434.
R. H. Mit-
[5] [5a]
X. H. Cheng, S. Diele, C. Tschierske, Angew. Chem. 2000,
chell, L. Mazuch, B. Shell, P. R. West, Can. J. Chem. 1978, 56,
[5b]
112, 605Ϫ608; Angew. Chem. Int. Ed. 2000, 39, 592Ϫ595.
A. Pegenau, T. Hegemann, C. Tschierske, S. Diele, Chem. Eur.
J. 1999, 5, 1643Ϫ1660.
Nishikawa, H. Finkelmann, M. Nimtz, Eur. J. Org. Chem.
[10f]
1246Ϫ1252.
M. V. Sargent, C. J. Timmons, J. Chem. Soc.
1964, 5544Ϫ5552.
[5c]
J. L. Schulte, S. Laschat, V. Vill, E.
[11]
[12]
Oxidative photocyclizations of o-terphenyls to liquid crystalline
triphenylenes have been used by Cammidge. For details see:
[5d]
1998, 2499Ϫ2506.
termann, S. Diele, Adv. Mater. 1997, 9, 398Ϫ403.
J. H. Cameron, A. Facher, G. Lat-
[11a]
A. N. Cammidge, H. Gopee, Chem. Commun. 2002,
[5e]
A. Peg-
[11b]
966Ϫ967.
A. N. Cammidge, H. Gopee, J. Mater. Chem.
enau, P. Göring, C. Tschierske, Chem. Commun. 1996,
2001, 11, 2773.
2563Ϫ2564. [5f] T. M. Swager, H. Zheng, Mol. Cryst. Liq. Cryst.
Reviews: [12a] A. Fürstner, B. Bogdanovic, Angew. Chem. 1996,
[5g]
1995, 260, 301Ϫ306.
U. Stebani, G. Lattermann, Adv.
108, 2582Ϫ2609; Angew. Chem. Int. Ed. Engl. 1996, 35,
[5h]
Mater. 1995, 7, 578Ϫ581.
H. Zheng, T. M. Swager, J. Am.
[12b]
2442Ϫ2469.
D. Lenoir, Synthesis 1989, 883Ϫ897.
Chem. Soc. 1994, 111, 761Ϫ762. [5i] J. Malthete, A. M. Levelut,
[13]
[14]
D. Lenoir, Synthesis 1977, 553Ϫ554.
[5j]
Adv. Mater. 1991, 3, 94Ϫ96.
A.-M. Giroud-Godquin, A.
M. G. Banwell, J. M. Cameron, M. Corbett, J. R. Dupuche, E.
Hamel, Aust. J. Chem. 1992, 45, 1967Ϫ1982.
A. Gottsegen, M. Nogradi, B. Vermes, M. Kajtar-Peredy, E.
Bihats-Kasai, J. Chem. Soc., Perkin Trans. 1 1990, 315Ϫ318.
The optical micrograph can be distorted by pressing the cover
slips, at lower temperature, however, in the mesophase the com-
pounds are highly viscous.
Rassat, C. R. Acad. Sci. Paris 1982, 294, 241Ϫ243.
C. Tschierske, J. Mater. Chem. 1998, 8, 1485Ϫ1508.
A. Schultz, S. Diele, S. Laschat, M. Nimtz, Adv. Funct. Mater.
2001, 11, 441Ϫ446.
Review: F. B. Mallory, C. W. Mallory, Org. React. 1984, 30,
1Ϫ456.
[6]
[7]
[15]
[16]
[8]
[9] [9a]
[17]
[18]
D. Kuck, A. Schuster, R. A. Krause, J. Tellenbroecker, C.
P. Exner, M. Penk, H. Boegge, A. Müller, Tetrahedron 2001,
A diffuse halo at 4.4 nm in the wide angle section corresponds
to the distance of the flexible alkyl side chains.
[9b]
[18a]
57, 3587Ϫ3614.
J. Org. Chem. 2000, 65, 7010Ϫ7019.
R. Rapp, A. Szoelloesy, J. Nyitrai, D. Döpp, J. Prakt. Chem.
R. Oliveira, P. San Martin, E. Dominguez,
Reviews:
A. Suzuki, Metal-catalyzed cross-coupling reac-
[9c]
J. Nagy, Z. Madarasz,
tions (Eds.: F. Diederich, P. J. Stang), Wiley-VCH, Weinheim,
[18b]
Germany, 1998, p. 49Ϫ97.
Rev. 1995, 95, 2457Ϫ2483.
N. Miyaura, A. Suzuki, Chem.
[9d]
2000, 342, 281Ϫ290.
L. Eshdat, A. Ayalon, R. Beust, R.
[19]
[20]
[21]
Shenhar, M. Rabinovitz, J. Am. Chem. Soc. 2000, 122,
J. F. Morris, J. Am. Chem. Soc. 1916, 38, 702Ϫ711.
R. J. Olsen, R. E. Buckles, J. Photochem. 1979, 10, 215Ϫ220.
I. M. Davidson, O. C. Musgrave, D. L. Manson, J. Chem. Soc.
1965, 3040Ϫ3044.
R. H. Mitchell, L. Mazuch, B. Shell, P. R. West, Can. J. Chem.
1978, 56, 1246Ϫ1252.
It should be kept in mind that all the tetraphenylethenes re-
ported in this work possess a twisted structure as the unsubsti-
tuted parent compound due to overlapping ortho hydrogen
atoms.
M. C. Artal, K. J. Toyne, J. W. Goodby, J. Barbera, D. J. Phot-
inos, J. Mater. Chem. 2001, 11, 2801Ϫ2807.
Received February 26, 2003
[9e]
12637Ϫ12645.
J. Tellenbroecker, D. Kuck, Angew. Chem.
1999, 111, 1000Ϫ1004; Angew. Chem. Int. Ed. 1999, 38,
[9f]
919Ϫ922.
T. Ogino, F. Wada, T. Murayama, S. Aoki, K.
Ohshima, Tetrahedron Lett. 1996, 37, 7065Ϫ7068. [9g] A. Cout-
[22]
[23]
ure, E. Deniau, P. Grandclaudon, C. Simion, Synthesis 1996,
[9h]
986Ϫ990.
C. Niu, T. Petterson, M. J. Miller, J. Org. Chem.
[9i]
1996, 61, 1014Ϫ1022.
T. Sato, S. Shimada, K. Hata, Bull.
Chem. Soc. Jpn. 1971, 44, 2484Ϫ2490. [9j] T. Sato, S. Shimada,
K. Hata, Bull. Chem. Soc. Jpn. 1969, 42, 766Ϫ772. [9k] T. Sato,
[9l]
[24]
Y. Goto, K. Hata, Bull. Chem. Soc. Jpn. 1967, 40, 1994.
Kharasch, T. G. Alston, H. B. Lewis, W. Wolf, J. Chem. Soc.,
Chem. Commun. 1965, 242Ϫ243.
N.
[9m]
F. B. Mallory, C. S.
Eur. J. Org. Chem. 2003, 2829Ϫ2839
www.eurjoc.org
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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