Structural factors controlling the transition between columnar-hexagonal and helical mesophase in triphenylene liquid crystals

Article abstract of DOI:10.1039/b103450m

A series of novel triphenylenes has been synthesised by a combination of palladium catalysed coupling, oxidative cyclisation, bromination and nucleophilic aromatic substitution. The new derivatives are designed to have structures which are intermediate between the known symmetrical materials hexakis(hexyloxy)triphenylene and hexakis(hexylthio)triphenylene. The compounds having four hexyloxy and two hexylthio substituents form only Col_h mesophases. Triphenylenes having four hexylthio and two hexyloxy substituents also give Col_h mesophases but 3,6-bis(hexyloxy)-2,7,10,11-tetrakis(hexylthio)triphenylene 5 is unique in that it cools into a stable, more ordered phase. The low temperature phase, which appears to be indefinitely stable at ambient temperature, is assumed to be helical based on transition enthalpy data.

Full text of DOI:10.1039/b103450m

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Structural factors controlling the transition between columnar-
hexagonal and helical mesophase in triphenylene liquid crystals{
Andrew N Cammidge* and Hemant Gopee
School of Chemical Sciences, University of East Anglia, Norwich, UK NR4 7TJ.
E-mail: a.cammidge@uea.ac.uk
Received 18th April 2001, Accepted 22nd May 2001
First published as an Advance Article on the web 2nd October 2001
A series of novel triphenylenes has been synthesised by a combination of palladium catalysed coupling,
oxidative cyclisation, bromination and nucleophilic aromatic substitution. The new derivatives are designed to
have structures which are intermediate between the known symmetrical materials hexakis(hexyloxy)triphenylene
and hexakis(hexylthio)triphenylene. The compounds having four hexyloxy and two hexylthio substituents form
only Colh mesophases. Triphenylenes having four hexylthio and two hexyloxy substituents also give Colh
mesophases but 3,6-bis(hexyloxy)-2,7,10,11-tetrakis(hexylthio)triphenylene 5 is unique in that it cools into a
stable, more ordered phase. The low temperature phase, which appears to be indefinitely stable at ambient
temperature, is assumed to be helical based on transition enthalpy data.
because the only change to structure is replacement of 2 or 4
sulfides by alkoxides.
Introduction
Discotic liquid crystals1 have received widespread attention
since their discovery in 1977,2 not least because columnar
arrangement of (aromatic) cores gives rise to a low-dimensional
conduction pathway.3,4 Discotic liquid crystals based on the
triphenylene nucleus are particularly attractive because simple
derivatives are relatively easy to synthesise.1 Furthermore, it is
known that (homeotropic) alignment during slow cooling from
the isotropic phase is easily achieved when the material is
sandwiched in-between suitable substrates. Photoconductivity
studies have revealed a charge carrier mobility of about
1027 m2 v21 s21 along the columns of hexaalkoxytriphenylenes5
in their Colh mesophases (the anisotropy factor is about 103).
Hexakis(hexylthio)triphenylene6 has unique properties. In
addition to the Colh mesophase a more ordered helical (H)
phase7,8 is formed at lower temperatures. Charge carrier mobility
Results and discussion
Synthesis
The target molecules of this study are shown in Fig. 1, along
with the reference compounds hexakis(hexylthio)triphenylene 8
and hexakis(hexyloxy)triphenylene 1.
The synthesis of unsymmetrically substituted triphenylenes
can be achieved by coupling certain biphenyls and benzene
derivatives.21–23 Alternatively terphenyls can be constructed
and cyclised to the triphenylene is a separate step.24–26 The first
strategy was employed for synthesis of 2,3,6,7-tetrakis(hexyl-
oxy)-10,11-bis(hexylthio)triphenylene 2 as shown in Scheme 1.
Suzuki coupling27 of 4-bromoveratrole 9 with phenylboronic
acid 10 yielded 3,4-dimethoxybiphenyl 11. Oxidative coupling
with veratrole using ferric chloride21,28 yielded 2,3,6,7-tetra-
methoxytriphenylene 12 directly. This oxidative coupling is
successful because of the complementary functionality on the
two partners (the biphenyl is most susceptible to oxidation
and the dialkoxybenzene is susceptible to electrophilic attack).
Removal of the methyl groups (HBr in acetic acid) followed
by realkylation with 1-bromohexane afforded 2,3,6,7-
tetrakis(hexyloxy)triphenylene 13. Bromination with molecular
bromine introduced bromide at both free b-positions to give
2,3-dibromo-6,7,10,11-tetrakis(hexyloxy)triphenylene 14.29 Dis-
placement of the bromides using hexanethiol yielded 2.
Syntheses of the isomers 3 and 4 were achieved following
related strategies (Schemes 2 and 3). The synthesis of 3 started
with 4-bromophenol 16 which was alkylated and converted to
the corresponding boronic acid via formation of the Grignard
reagent and quench with trimethyl borate. Double Suzuki
coupling with 1,2-dibromo-3,4-bis(hexyloxy)benzene 15 (pre-
pared by bromination of 1,2-bis(hexyloxy)benzene) gives
terphenyl 19. Treatment of 19 with ferric chloride results in
no formation of triphenylene product because the electronic
(directing) effects of the 4’-alkoxy substituents do not favour
either location of positive charge on the 3’-position or electro-
philic attack on the 3@-position. Consequently cyclisation was
achieved photochemically26 to give 2,3,7,10-tetrakis(hexyl-
oxy)triphenylene 20. Bromination again gave exclusive sub-
stitution at the free b-positions yielding 2,7-dibromo-3,6,10,
in this phase is substantially higher (1025 m2 v21 s21 9–11
and
)
the dramatic increase is attributed to the long-range molecular
order in the helical phase. It is interesting to note that the
helical phase is not observed if the chain length is changed,7 or
indeed if the heteroatom is substituted for selenium.12
A number of attempts have been made to generate more
ordered columnar mesophases from unsymmetrically substi-
tuted triphenylene derivatives. Selective hydrolytic removal of
1–3 alkyl chains from hexaalkyloxytriphenylenes (or selective
alkylations) can be readily achieved.13–17 Removal of three
chains (one from each ‘‘benzene’’) gives two isomeric trihydroxy-
triphenylenes13,14 which can be separated and further function-
alised. In this way mixed chain derivatives have been prepared
in order to promote interdigitation of alkyl chains (and increase
order).18 Two short reports outline deoxygenation of the
intermediates to give tris(pentyloxy)triphenylenes.19,20 These
can be further functionalised by bromination19,20 and the
bromides displaced to yield tris(pentyloxy)tris(pentylthio)tri-
phenylenes20 (which, as would be expected, do not exhibit the
helical mesophase).
This paper describes rational, atom-efficient syntheses of
isomerically pure triphenylenes which are directly compar-
able to helical phase-forming hexakis(hexylthio)triphenylene
{Basis of a presentation given at Materials Discussion No. 4, 11–14
September 2001, Grasmere, UK.
DOI: 10.1039/b103450m
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This journal is # The Royal Society of Chemistry 2001
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Scheme 1 Hx~n-hexyl. Reagents and conditions: (i) PdCl2, Na2CO3,
PPh3, toluene–EtOH–H2O, reflux, 4 h, (ii) FeCl3, CH2Cl2, rt, 2 h, (iii)
HBr, HOAc, reflux, 24 h, (iv) HxBr, EtOH, K2CO3, reflux, 24 h, (v)
Br2, CH2Cl2, 25 uC, 2 h, (vi) HxSH, KOtBu, NMP, 70 uC, 24 h.
Treatment with ferric chloride did not yield the expected
triphenylene 37 but rather 36, in which cyclisation with
concomitant chlorination had occurred. Chlorination presum-
ably occurs via an oxidation–chlorination–oxidation (aroma-
tisation) pathway30 (Scheme 7) which leads to our assumption
that chloride is introduced at the 7,10-positions. Photochemical
cyclisation was therefore successfully employed affording 37 in
reasonable yield.
Fig. 1 Target molecules 1–8.
11-tetrakis(hexyloxy)triphenylene 21. Substitution of the
bromides with hexanethiol gave 3.
Synthesis of 4 was achieved following an almost identical
strategy starting from 3-bromophenol. In this case, however,
intermediate terphenyl 25 can be easily cyclised to triphenylene
26 by treatment with ferric chloride. Bromination and sub-
stitution with hexanethiol yielded 4.
Bromination of 37 was attempted using the conditions which
proved successful for the synthesis of 31 and 34 (Scheme 8). In
the case of 37, however, prolonged treatment with bromine
in dichloromethane yielded a mixture of products which were
The synthesis of bis(hexyloxy)tetrakis(hexylthio)tripheny-
lenes 5 and 6 was achieved following related coupling–
cyclisation protocols as shown in Schemes 4 and 5. Suzuki
coupling between 1,2-dibromobenzene and 4-hexyloxyphenyl-
boronic acid 18 gave terphenyl 29. As expected, cyclisation to
the corresponding triphenylene 30 could not be achieved using
ferric chloride and required photochemical oxidation (hn–I2).
The four free b-positions of triphenylene 30 were smoothly
brominated with molecular bromine to give tetrabromide 31
and nucleophilic displacement of the bromides with hexanethiol
afforded target 3,6-bis(hexyloxy)-2,7,10,11-tetrakis(hexylthio)-
triphenylene 5. Synthesis of 6 followed an almost identical
route. However, in this case it was again possible to cyclise
intermediate terphenyl 32 to triphenylene 33 simply using ferric
chloride.
1
presumed to be polybromides. Examination of the H NMR
spectrum of the crude product confirmed that none of the
desired tetrabromide was present. Progressively more forcing
bromination conditions were used (raised temperature, Lewis
acid catalyst) but the desired product was never observed.
Alternative, longer routes were therefore investigated for the
synthesis of 7. Bromination of dichloride 36 was attempted
(Scheme 9) because it was envisaged that the dibromodichloro-
triphenylene 38 could be easily converted to 7 by displacement
of both halides. Treatment of 36 with bromine at room
temperature gave smooth dibromination. However, it was clear
from the 1H NMR spectrum of the product that 1,4-dibromide
39 had been formed. Attempts to prepare 38 (the expected
thermodynamic product) using alternative conditions (Lewis
acid and elevated temperature, iodine monochloride) were all
unsuccessful. It was hoped that synthesis of 7 could be achieved
in a stepwise manner (Scheme 10). Consequently dichloride 36
was treated with hexanethiol to give 2,3-bis(hexyloxy)-7,
It was envisaged that synthesis of the isomeric triphenylene
7 could be achieved following a similar strategy via 2,3-
bis(hexyloxy)triphenylene 37 (Scheme 6). 1,2-Dibromo-3,4-
bis(hexyloxy)benzene 15 and phenylboronic acid were coupled
together under Suzuki conditions to give the terphenyl 35.
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Scheme 3 Hx~n-hexyl. Reagents and conditions: (i) HxBr, EtOH,
K2CO3, reflux, (ii) Mg, Et2O, (iii) B(OMe)3, (iv) H3Oz, (v) PdCl2,
Na2CO3, PPh3, toluene–EtOH–H2O, reflux, 4 h, (vi) FeCl3, CH2Cl2, rt,
2 h, (vii) Br2, CH2Cl2, 0 uC, 30 min, (viii) HxSH, KOtBu, NMP, 70 uC,
24 h.
been pre-cooled to 280 uC reveals melting points (K–Colh) of
63 uC and 40 uC respectively. Both have clearing points around
179 uC. Their columnar phases (assigned as Colh on the basis of
their characteristic textures) are stable down to below ambient
temperature.
Mixed hexyloxy-/hexylthio-triphenylenes show mesophase
behaviour which is dependent on the position and relative
number of substituents. 2,3,6,7-Tetrakis(hexyloxy)-10,11-
bis(hexylthio)triphenylene 2 melts directly from the crystalline
solid to isotropic liquid at 86 uC. When the isotropic liquid is
Scheme 2 Hx~n-hexyl. Reagents and conditions: (i) Br2, CH2Cl2, 0 uC,
2 h, (ii) HxBr, EtOH, K2CO3, reflux, (iii) Mg, Et2O, (iv) B(OMe)3, (v)
H3Oz, (vi) PdCl2, Na2CO3, PPh3, toluene–EtOH–H2O, reflux, 4 h, (vii)
hn, I2, benzene, 72 h, (viii) Br2, CH2Cl2, 0 uC, 30 min, (ix) HxSH,
KOtBu, NMP, 70 uC, 24 h.
10-bis(hexylthio)triphenylene 40. It was hoped that bromina-
tion would yield dibromide 41 which could be converted into 7
by another nucleophilic displacement. Surprisingly, treatment
of 40 with bromine resulted in no reaction, even at elevated
temperatures.
Mesophase behaviour
The mesophase behaviour of the novel triphenylene derivatives
was investigated by polarising optical microscopy and differ-
ential scanning calorimetry (DSC). As expected, intermed-
iate terphenyls, both di- and tetra-substituted triphenylenes
and dialkoxytetrahalogenotriphenylenes proved to be non-
mesogenic. Dibromotetrakis(hexyloxy)triphenylenes 14, 21
and 27 do, however, exhibit enantiotropic liquid crystal
phases (Table 1). The 2,7- and 3,6-dibromides 21 and 27 are
particularly interesting. First heating of samples which have
Scheme 4 Hx~n-hexyl. Reagents and conditions: (i) 15, PdCl2,
Na2CO3, PPh3, toluene–EtOH–H2O, reflux, 4 h, (ii) hn, I2, benzene,
72 h, (iii) Br2, CH2Cl2, rt, 2 h, (iv) HxSH, KOtBu, NMP, 70 uC, 24 h.
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Scheme 5 Hx~n-hexyl. Reagents and conditions: (i) 24, PdCl2,
Na2CO3, PPh3, toluene–EtOH–H2O, reflux, 4 h, (ii) FeCl3, CH2Cl2,
rt, 2 h, (iii) Br2, CH2Cl2, rt, 2 h, (iv) HxSH, KOtBu, NMP, 70 uC, 24 h.
cooled, a monotropic Colh mesophase forms at 81 uC which
remains until the sample recrystallises at 52 uC. Substitution of
hexylthio groups at the 2,7- or 3,6-positions (3 and 4) leads
to materials with enhanced mesophase stability and also sup-
presses crystallisation. Triphenylene 3 (pre-cooled to 280 uC)
has a melting point (K–Colh) of 24 uC and clears at 102 uC.
The material cools into a Colh phase at 99 uC and does not
recrystallise down to below 0 uC. Similarly triphenylene 4
(which on first heating gives a melting point of 45 uC) gives a
Colh phase from 118 uC down to below ambient temperature
(Table 2). No additional transitions are observed for either
sample by microscopy or DSC.
Triphenylenes 5 and 6, which have four hexylthio- and two
hexyloxy-substituents, are closely related to hexakis(hexyl-
thio)triphenylene 8 and were considered most likely to exhibit
the helical phase. 2,7-Bis(hexyloxy)-3,6,10,11-tetrakis(hexyl-
thio)triphenylene 6, as prepared, is liquid crystalline at room
temperature. DSC (after cooling to 280 uC) reveals a melting
point of 54 uC and a clearing point of 100.5 uC. Cooling the
sample gives rise to a Colh mesophase (as evidenced by
microscopy) at 97 uC which is stable down to below ambient
Scheme 7 Mechanism for the formation of 36.
temperature. No further transitions were evident by micro-
scopy or DSC.
Isomeric 3,6-bis(hexyloxy)-2,7,10,11-tetrakis(hexylthio)tri-
phenylene 5 is unique in this series. First heating reveals a
melting point of 72 uC and clearing point of 111 uC. When
the sample is cooled a Colh mesophase is produced below
108 uC. Further cooling gives another, reversible transition
at 32 uC (38 uC on heating) (Fig. 2). The enthalpy of this
transition6 (1.1 J g21 compared to 0.8 J g21 for Colh–I and
4.7 J g21 for K–Colh) leads to the preliminary assignment
that this is indeed a Colh–H transition. The transition can
also be observed by microscopy as a discernible brightening
of the homeotropic regions of the sample. The phase appears
to be indefinitely stable at ambient temperature and no
Scheme 6 Hx~n-hexyl. Reagents and conditions: (i) 10, PdCl2,
Na2CO3, PPh3, toluene–EtOH–H2O, reflux, 48 h, (ii) FeCl3, CH2Cl2,
rt, 2 h, (iii) hn, I2, benzene, 72 h.
Scheme 8 Attempted bromination of 2,3-bis(hexyloxy)triphenylene 37.
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Table 1 Transition temperatures (uC) of dibromotetrakis(hexyloxy)-
triphenylenes
Heating
Cooling
Compound Structure
K–Colh Colh–I I–Colh Colh–K
1429
130
40a
63a
141
179
179
140
176
175
97
21
vRT
Scheme 9 Reagents and conditions: (i) Br2, CH2Cl2, rt, 2 h.
crystallisation is observed when the sample is cooled down to
240 uC (DSC) (Table 3).
These observations provide further evidence that forma-
tion of helical mesophases in triphenylene discogens requires
specific molecular structure. Previously the phase has only
been observed for symmetrical hexakis(hexylthio)triphenylene
8—derivatives with different chain lengths exhibit Colh phases
only. We have now shown that an additional phase (assumed to
be helical) is formed when 3,6-bis(hexyloxy)-2,7,10,11-tetra-
kis(hexylthio)triphenylene 5 is cooled. Its isomer 2,7-bis(hexyl-
oxy)-3,6,10,11-tetrakis(hexylthio)triphenylene 6, however, does
not show this behaviour. This observation further emphasises
the structural subtlety required for generation of the addi-
tional, more ordered mesophase. Most important, perhaps, is
the observation that the more ordered phase of 5 can be cooled
to ambient temperature and below (the helical phase of 8 can
only be supercooled to about 40 uC9). This observation opens
up the possibility of using the materials in room temperature
devices. It is likely that the phase can be stabilised further
through careful synthetic modification and through formation
of mixtures. All the materials tend to form homeotropically
aligned films when cooled from the isotropic liquid (typical for
27
vRT
aObserved if sample is pre-cooled to 280 uC.
Fig. 2 DSC of 5 (heating/cooling rate 5 uC min21).
triphenylenes and other discotic liquid crystals31) and this
property is also likely to be important for device fabrication.
Conclusions
A series of mixed hexyloxy-/hexylthio-triphenylenes has been
synthesised to determine the structural features governing the
formation of helical mesophases. It has been shown that four
sulfide substituents (plus two alkoxides) are required to induce
the additional, more ordered phase. Furthermore, the position
of substitution is crucial for its formation. 3,6-Bis(hexyloxy)-
2,7,10,11-tetrakis(hexylthio)triphenylene 5 gives the phase
when cooled from the Colh mesophase and it is stable below
ambient temperature. However, its isomer 2,7-bis(hexyloxy)-
3,6,10,11-tetrakis(hexylthio)triphenylene 6 only gives the Colh
Scheme 10 Reagents and conditions: (i) HxSH, KOtBu, NMP, 70 uC,
24 h.
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Table 2 Transition temperatures (uC) and enthalpies (J g21) of tetrakis(hexyloxy)bis(hexylthio)triphenylenes
Heating
Cooling
Compound
Structure
K–Colh (DH)
(K–I 86)
Colh–I (DH)
I–Colh (DH)
Colh–K (DH)
2
81 (0.5)
52 (5.6)
3
24a (3.3)
102 (0.7)
99 (0.8)
v0
4
45a (4.5)
123 (0.8)
118 (0.8)
v0
aObserved if sample is pre-cooled to 280 uC.
Table 3 Transition temperatures (uC) and enthalpies (J g21) of bis(hexyloxy)tetrakis(hexylthio)triphenylenes
Heating
Cooling
Compound
Structure
K–Colh (DH)a
72 (4.7)
H–Colh (DH)
Colh–I (DH)
I–Colh (DH)
108 (0.8)
Colh–H (DH)
32 (1.1)
D–K
5
38 (1.3)
111 (0.8)
v240
6
54 (4.0)
—
100.5 (0.6)
97 (0.8)
—
vRT
aObserved if sample is pre-cooled to 280 uC.
phase. Further studies are underway to extend the series and
confirm the structure of the low temperature phase of 5.
1106 elemental analyser at UEA. Mass spectra were recorded
at the EPSRC National Mass Spectrometry Service Centre
at the University of Wales, Swansea. Transition temperatures
were observed using an Olympus BH-2 polarising microscope
with a TMS 92 thermal analyser and Linkham THM 600 cell.
Differential scanning calorimetry was performed on a TA DSC
Experimental
NMR spectra were recorded on either a JEOL EX270 FT or
Varian 300 MHz spectrometer (coupling constants are quoted
in Hz). Elemental analyses were performed on a Carlo Erba
10 instrument with a heating/cooling rate of 5 or 10 uC min21
Column chromatography was performed at atmospheric
.
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pressure using Lancaster silica gel 60, 0.060–0.2 mm (7–230
mesh). Commercially available starting materials were used
without further purification.
149.8, 149.4, 129.2, 126.2, 124.4, 123.9, 123.1, 107.4, 107.3,
69.8, 69.5, 31.7(6), 31.7(4), 29.4(8), 29.4(2), 25.9, 22.7, 14.1; m/z
(EI) 628 (Mz, 30%).
3,4-Dimethoxybiphenyl 11
2,3-Dibromo-6,7,10,11-tetrakis(hexyloxy)triphenylene 14
Phenylboronic acid 10 (39.3 g, 0.322 mol), 4-bromoveratrole 9
(35 g, 0.161 mol), sodium carbonate (50 g, 0.483 mol), palla-
dium chloride (0.51 g, 4.8361023 mol) and triphenylphos-
phine (2.53 g, 9.6661023 mol) were stirred under reflux in a
mixture of toluene, ethanol and water (3 : 3 : 1, 200 mL) for
48 hours. The solvents were evaporated, water added and
the mixture extracted with dichloromethane (46150 mL). The
crude product was purified by column chromatography
(eluting with 1 : 1 dichloromethane–petroleum ether) to give
the title compound as colourless crystals (21.32 g, 62%).
Anal. Found: C 78.33; H 6.57 (C14H14O2 requires C 78.50; H
6.54%); dH (CDCl3, TMS, 300 MHz) 7.56 (2H, m), 7.42 (2H, t,
J~7.2), 7.33 (1H, m), 7.16–7.14 (2H, m), 6.95 (1H, d, J~8.1),
3.95 (3H, s), 3.92 (3H, s); dC (75.45 MHz; CDCl3) 149.5, 148.9,
141.3, 134.5, 128.9, 127.1, 119.6, 111.7, 110.7, 56.1, 56.0; m/z
(EI) 214 (Mz, 100%).
2,3,6,7-Tetrakis(hexyloxy)triphenylene 13 (2.0 g, 3.261023 mol)
was dissolved in dichloromethane (100 mL). The mixture was
cooled using an ice–salt bath and bromine (3.0 g, 0.019 mol)
was added drop-wise until the red colour persisted. The mixture
was stirred for 2 hours following which sodium metabisulfite
solution (20%) was added. The mixture was extracted using
dichloromethane (36150 mL) and the crude product was
precipitated by addition of excess methanol. Purification by
column chromatography (using petroleum ether–dichloro-
methane (4 : 1) as eluent) gave the title compound (2.12 g, 85%).
Anal. Found: C, 64.36; H 7.43 (C42H60O4 requires C, 64.12;
H 7.38%); dH (CDCl3, TMS, 300 MHz) 8.62 (2H, s), 7.79 (2H,
s), 7.76 (2H, s), 4.23 (8H, m), 1.95 (8H, m), 1.49 (24H, m), 0.88
(12H, m); dC (75.45 MHz; CDCl3) 150.2, 149.3, 129.3, 127.6,
124.5, 121.7, 120.2, 106.7, 106.4, 69.6, 69.4, 31.7, 29.4, 25.9,
22.7, 14.1; m/z (EI) 786 (Mz, 100%).
2,3,6,7-Tetramethoxytriphenylene 12
2,3,6,7-Tetrakis(hexyloxy)-10,11-bis(hexylthio)triphenylene 2
Veratrole (20 g, 0.148 mol) and 3,4-dimethoxybiphenyl 11
(8.0 g, 0.037 mol) were dissolved in dichloromethane
(150 mL). Iron(III) chloride (45 g, 0.29 mol) was added and
the mixture stirred for 2 hours at room temperature. Methanol
was then carefully added followed by water. The mixture was
extracted with dichloromethane (36150 mL) and the sol-
vents evaporated. The crude product was purified by column
chromatography (eluting with 4 : 1 petroleum ether–ethyl
acetate) to give 12 as colourless crystals (9.37 g, 72%).
Anal. Found: C, 75.74; H 5.72 (C22H20O4 requires C, 75.86;
H 5.75%); dH (CDCl3, TMS, 300 MHz) 8.51 (2H, m), 8.00 (2H,
s), 7.80 (2H, s), 7.61 (2H, m), 4.14 (6H, s), 4.13 (6H, s); dC
(75.45 MHz, CDCl3) 149.5, 148.9, 128.9, 126.2, 123.6, 122.9,
121.0, 104.6, 104.2, 56.1, 55.9; m/z (EI) 348 (Mz, 100%).
Potassium tert-butoxide (0.855 g, 7.6361023 mol) was added
to a stirred solution of hexanethiol (0.90 g, 7.6361023 mol)
in 1-methyl-2-pyrrolidone (NMP) (10 mL). The solution was
heated to 100 uC for 5 minutes and then cooled to 70 uC. 2,3-
Dibromo-6,7,10,11-tetrakis(hexyloxy)triphenylene 14 (1.50 g,
1.9061023 mol) was added and the solution was stirred for
24 hours. 1-Bromohexane (0.63 g, 3.7561023 mol) was added
and the mixture stirred for 24 hours at room temperature. The
solution was worked up by addition of water and the organic
layer separated. The aqueous layer was further extracted with
diethyl ether (3620 mL). The organic extracts were combined,
washed with brine, dried (Na2SO4) and the solvents evapo-
rated. The crude product was purified by column chromato-
graphy (eluting with 9 : 1 petroleum ether–dichloromethane)
and recrystallised from ethanol to give the title compound
(0.57 g, 35%).
2,3,6,7-Tetrahydroxytriphenylene
Anal. Found: C, 75.15; H 9.70; S 7.48 (C54H84O4S2 requires
C, 75.35; H 9.77; S 7.44%); dH (CDCl3, TMS, 300 MHz) 8.34
(2H, s), 7.92 (2H, s), 7.81 (2H, s), 4.26–4.20 (8H, m), 3.09 (4H,
t, J~7.4) 1.99–1.90 (8H, m), 1.79–1.72 (4H, m), 1.63–1.38
(36H, m), 0.95–0.85 (18H, m); dC (75.45 MHz; CDCl3) 150.0,
149.5, 135.6, 127.8, 124.6, 124.2, 123.2, 107.4, 107.3, 69.9, 69.7,
34.3, 31.7, 31.6, 29.4, 29.0, 28.9, 25.8, 22.7, 22.6, 14.1; m/z
(FABMS) 860 (Mz, 100%).
2,3,6,7-Tetramethoxytriphenylene 12 (12.0 g, 0.034 mol) was
added to a refluxing mixture of hydrobromic acid–acetic acid
(1 : 1, 500 mL). The solution was refluxed for 24 hours. The
solvents were evaporated and dilute sodium hydrogen carbo-
nate was added. The mixture was extracted with ethyl acetate
and purified by column chromatography (using dichloro-
methane as eluent) to give the title compound (9.66 g, 96%)
which was used without further purification.
d
H (d6-Acetone), TMS, 300 MHz) 8.46 (2H, m), 8.11 (2H, s),
1,2-Dibromo-4,5-bis(hexyloxy)benzene 15
7.91 (2H, s), 7.53 (2H, m), 2.05 (4H, br s); m/z (EI) 292 (Mz,
100%).
1,2-Bis(hexyloxy)benzene (5.00 g, 0.017 mol) was stirred in
dichloromethane at 0 uC. Bromine (6.00 g, 0.0375 mol) was
added drop-wise and the solution stirred for a further 2 hours.
A solution of sodium metabisulfite was added and the organic
layer separated. The aqueous layer was further extracted with
dichloromethane (36150 mL). The combined organic extracts
were washed with brine, dried (Na2SO4) and the solvents
evaporated to give the title compound as a colourless oil
(5.50 g, 70%) which was used without further purification.
dH (CDCl3, TMS, 300 MHz) 7.06 (2H, s), 3.94 (4H, t,
J~6.6), 1.84–1.75 (4H, m), 1.50–1.30 (12H, m), 0.93–0.87 (6H,
t, J~6.9).
2,3,6,7-Tetrakis(hexyloxy)triphenylene 13
2,3,6,7-Tetrahydroxytriphenylene (10.0 g, 0.03 mol), 1-bromo-
hexane (29.7 g, 0.80 mol) and anhydrous potassium carbonate
(25.0 g, 0.80 mol) were stirred in refluxing ethanol (200 mL)
under nitrogen for 24 hours. The solids were then filtered off
and washed with ethanol. The solvents were evaporated and
dilute sulfuric acid was added. The mixture was extracted with
dichloromethane (36150 mL) and the solvents evaporated.
The crude residue was dissolved in dichloromethane and
precipitated with methanol. The solid was recrystallised from
ethanol to give the title compound as a colourless solid (20.6 g,
95%).
4,4’,5’,4@-Tetrakis(hexyloxy)-1,1’:2’,1@-terphenyl 19
Anal. Found: C, 80.13; H, 9.55 (C42H60O4 requires C, 80.25;
H 9.55%); dH (CDCl3, TMS, 300 MHz) 8.49 (2H, m), 8.02 (2H,
s), 7.85 (2H, s), 7.58 (2H, m), 4.28 (8H,), 1.94 (8H, m), 1.58 (8H,
m), 1.40 (16H, m), 0.94 (12H, t, J~7); dC (75.45 MHz; CDCl3)
4-Hexyloxyphenylboronic acid 18 (15.0 g, 0.056 mol), 1,2-
dibromo-4,5-bis(hexyloxy)benzene 15 (10.00 g, 0.023 mol),
sodium carbonate (8.00 g, 0.075 mol), palladium chloride
(0.12 g, 3.4461024 mol) and triphenylphosphine (0.12 g,
J. Mater. Chem., 2001, 11, 2773–2783
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6.8861024 mol) were stirred under reflux in a mixture of
toluene, ethanol and water (3 : 3 : 1, 100 mL) for 24 hours. The
solvents were evaporated and water was added. The mixture
was extracted with dichloromethane (46150 mL) and the
solvents evaporated. The crude product was purified by column
chromatography (eluting with 1 : 4 petroleum ether–dichloro-
methane), to give the title compound as a colourless oil (9.86 g,
68%).
Anal. Found: C 79.9; H 9.87 (C42H62O4 requires C 80.00; H
9.84%); dH (CDCl3, TMS, 300 MHz) 7.03 (2H, d, J~8.8), 6.89
(2H, s), 6.74 (6H, d, J~8.8), 4.04 (4H, t, J~6.6), 3.91 (4H, t,
J~6.6), 1.88–1.71 (8H, m), 1.59–1.03 (32H, m), 0.93–0.83
(12H, m); dC (75.45 MHz; CDCl3) 157.6, 148.2, 133.9, 132.7,
130.8, 116.3, 113.9, 69.4, 67.8, 31.4, 29.2, 29.1, 25.6, 22.4(3),
22.4(0), 13.8; m/z (EI) 630 (Mz, 50%).
(Na2SO4) and the solvents evaporated. The crude product was
purified by column chromatography (eluting with 9 : 1
petroleum ether–dichloromethane) and recrystallised from
ethanol to give the title compound (0.55 g, 20%).
dH (CDCl3, TMS, 300 MHz) 8.29 (2H, s), 7.86 (2H, s), 7.75
(2H, s), 4.28–4.20 (8H, m), 3.08 (4H, t, J~7.4), 1.99–1.92 (8H,
m), 1.80–1.70 (4H, m), 1.58–1.25 (36H, m), 0.96–0.89 (18H, m);
dC (75.45 MHz; CDCl3) 155.9, 149.4, 128.2, 126.6, 124.2, 124.1,
123.3, 106.9, 104.4, 69.7, 69.1, 32.5, 31.7, 31.5, 29.5, 29.4, 29.1,
28.9, 25.9, 25.8, 22.7, 22.6, 14.1; m/z (FABMS) 861 (MzzH,
100%); Acc. Mass (ES) 861.5879 (C54H85O4S2 (MzH)~
861.5889).
3,4’,5’,3@-Tetrakis(hexyloxy)-1,1’:2’,1@-terphenyl 25
3-Hexyloxyphenylboronic acid 24 (15.0 g, 0.056 mol), 1,2-
dibromo-4,5-bis(hexyloxy)benzene 15 (10.00 g, 0.023 mol),
sodium carbonate (8.00 g, 0.075 mol), palladium chloride
(0.12 g, 3.4461024 mol) and triphenylphosphine (0.12 g,
6.8861024 mol) were stirred under reflux in a mixture of
toluene, ethanol and water (3 : 3 : 1, 100 mL) for 24 hours. The
solvents were evaporated, water added and the mixture was
extracted with dichloromethane (46150 mL). The solvents
were evaporated and the crude product was purified by column
chromatography (eluting with 1 : 4 petroleum ether–dichloro-
methane), to give the title compound as a colourless oil
(10.40 g, 72%).
Anal. Found: C 79.89; H 9.88 (C42H62O4 requires C 80.00; H
9.84%); dH (CDCl3, TMS, 300 MHz) 7.10 (2H, t, J~7.9), 6.95
(2H, s), 6.75–6.66 (6H, m), 4.06 (4H, t, J~6.6), 3.73 (4H, t,
J~6.6), 1.89–1.79 (4H, m), 1.70–1.61 (4H, m), 1.56–1.26 (24H,
m), 0.93–0.83 (12H, m); dC (75.45 MHz; CDCl3) 158.9, 148.7,
143.2, 133.3, 128.9, 122.4, 116.3, 116.2, 113.2, 69.6, 68.0, 31.7,
31.6, 29.4, 29.2, 25.8, 25.7, 22.7, 14.1; m/z (EI) 630 (Mz, 65%).
2,3,7,10-Tetrakis(hexyloxy)triphenylene 20
4,4’,5’,4@-Tetrakis(hexyloxy)-1,1’:2’,1@-terphenyl 19 (2.071 g,
4.361023 mol) and iodine (1.09 g, 4.361023 mol) were
dissolved in benzene (250 mL). The mixture was stirred and
irradiated with ultra-violet light at room temperature for
72 hours. Sodium metabisulfite solution was added to the
mixture and the organic phase separated. The aqueous layer
was further extracted with dichloromethane (36100 mL) and
the combined organic extracts were dried (MgSO4). The solvent
was removed in vacuo and the crude product purified by
column chromatography (eluting with 1 : 1 petroleum ether–
dichloromethane) to give the title compound (1.43 g, 53%) as a
colourless solid.
Mp 85 uC. Anal. Found: C 80.18; H 9.50 (C42H60O4 requires
C 80.25; H 9.55%); dH (CDCl3, TMS, 300 MHz) 8.38 (2H, d,
J~9.1), 7.95 (2H, d, J~2.6), 7.90 (2H, s), 7.25 (2H, dd, J~9.1
and 2.6), 4.24–4.16 (8H, m), 1.96–1.85 (8H, m), 1.59–1.34 (24H,
m), 0.96–0.90 (12H, m); dC (75.45 MHz; CDCl3) 157.8, 143.9,
130.5, 124.6, 124.3, 123.7, 116.2, 107.2, 107.0, 69.6, 68.5, 31.7,
29.5, 29.4, 25.9, 25.8, 22.7, 14.1; m/z (EI) 628 (Mz, 40%).
2,3,6,11-Tetrakis(hexyloxy)triphenylene 26
3,4’,5’,3@-Tetrakis(hexyloxy)-1,1’:2’,1@-terphenyl 25 (1.0 g,
1.5961023 mol) was stirred in dichloromethane (20 mL) at
room temperature. Iron(III) chloride (0.51 g, 3.1761023 mol)
was added and the mixture stirred for a further two hours.
Methanol and water were then added and the mixture extracted
with dichloromethane (36100 mL). The combined organic
phases were dried (MgSO4) and the solvents were evaporated.
Purification of the crude product by column chromatography
(eluting with 1 : 4 dichloromethane–petroleum ether) followed
by recrystallisation with methanol gave the title compound
(0.57 g, 56%) as a cream powder.
Mp 101 uC; Anal. Found: C 80.44; H 9.56 (C42H60O4
requires C 80.25; H 9.55%); dH (CDCl3, TMS, 300 MHz) 8.44
(2H, d, J~9.0), 7.91 (2H, s), 7.85 (2H, d, J~2.4), 7.20 (2H, dd,
J~2.4 and 9.0), 4.26–4.15 (8H, m), 1.97–1.84 (8H, m), 1.60–
1.25 (24H, m), 0.96–0.85 (12H, m); dC (75.45 MHz; CDCl3)
157.6, 149.6, 129.9, 124.4, 124.2, 123.3, 114.5, 107.2, 106.9,
69.4, 68.2, 31.5, 29.3, 25.6, 22.4, 13.8; m/z (EI) 628 (Mz, 10%).
2,7-Dibromo-3,6,10,11-tetrakis(hexyloxy)triphenylene 21
2,3,7,10-Tetrakis(hexyloxy)triphenylene 20 (2.40 g, 3.826
1023 mol) was stirred in dichloromethane (10 mL) at 0 uC.
Bromine (1.24 g, 7.6461023 mol) was added drop-wise and the
solution stirred for 30 minutes. A solution of sodium metabi-
sulfite was then added and the mixture extracted with
dichloromethane (36100 mL). The combined organic layers
were dried (MgSO4) and the crude product purified by column
chromatography (eluting with 1 : 4 dichloromethane–petro-
leum ether). The product was recrystallised from propan-2-ol
to give the title compound (2.50 g, 83%).
Anal. Found: C 64.08; H 7.45; Br 20.31 (C42H58O4Br2
requires C 64.12; H 7.38; Br 20.36%); dH (CDCl3, TMS,
300 MHz) 8.33 (2H, s), 7.39 (2H, s), 7.36 (2H, s), 4.15–4.06 (8H,
m), 1.99–1.88 (8H, m), 1.62–1.38 (24H, m), 0.98–0.94 (12H, m);
dC (75.45 MHz; CDCl3) 153.5, 149.5, 128.5, 127.6, 124.9, 122.2,
113.5, 105.8, 105.4, 69.4, 31.8, 31.7, 29.5, 29.3, 25.9, 22.8, 22.7,
14.1; m/z (FABMS) 786 (Mz, 100%).
2,11-Dibromo-3,6,7,10-tetrakis(hexyloxy)triphenylene 27
2,3,6,11-Tetrakis(hexyloxy)triphenylene 26 (0.50 g, 7.966
1024 mol) was stirred in dichloromethane (10 mL) at 0 uC.
Bromine (0.25 g, 1.5961023 mol) was added drop-wise and
the solution stirred for 30 minutes. A solution of sodium
metabisulfite was then added and the mixture was extracted
with dichloromethane (36100 mL). The combined organic
layers were dried (MgSO4), the solvents evaporated and the
crude product purified by column chromatography (eluting
with 1 : 1 dichloromethane–petroleum ether) and recrystallised
from propan-2-ol to give the title compound (0.40 g, 64%) as a
colourless solid.
2,3,7,10-Tetrakis(hexyloxy)-6,11-bis(hexylthio)triphenylene 3
Potassium tert-butoxide (3.57, 0.030 mol) was added to a
stirred solution of hexanethiol (3.54 g, 0.030 mol) in NMP
(25 mL). The solution was heated to 100 uC for 5 minutes and
then cooled to 70 uC. 2,7-Dibromo-3,6,10,11-tetrakis(hexyl-
oxy)triphenylene 21 (2.50 g, 3.1861023 mol) was added and
the solution was stirred for 24 hours. 1-Bromohexane (1.25 g,
7.5761023 mol) was added and the mixture stirred for
24 hours at room temperature. The solution was worked up
by addition of water and the organic layer separated. The
aqueous layer was extracted with diethyl ether (3650 mL). The
organic extracts were combined, washed with brine, dried
Anal. Found: C 64.42; H 7.43; Br 20.00 (C42H58O4Br2
requires C 64.12; H 7.38; Br 20.36%); dH (CDCl3, TMS,
2780
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300 MHz) 8.33 (2H, s), 7.75 (2H, s), 7.60 (2H, s), 4.27–4.18 (8H,
m), 2.67–1.91 (8H, m), 1.62–1.25 (24H, m), 0.97–0.92 (12H, m);
dC (75.45 MHz; CDCl3) 153.9, 149.9, 129.1, 127.4, 123.9, 122.9,
112.4, 107.1, 105.1, 69.6, 69.4, 31.8, 31.7, 29.5, 29.3, 25.9, 25.8,
22.7, 22.6, 14.1; m/z (FABMS) 786 (Mz, 10%).
126.2, 124.8, 124.0, 122.7, 115.9, 106.9, 68.1, 31.5, 29.2, 25.7,
22.4, 13.9; m/z (EI) 428 (Mz, 50%).
2,3,6,11-Tetrabromo-7,10-bis(hexyloxy)triphenylene 31
3,6-Bis(hexyloxy)triphenylene 30 (0.50 g, 1.1661023 mol) was
stirred in dichloromethane (10 mL) at room temperature.
Bromine (1.86 g, 0.012 mol) was added drop-wise and the
solution stirred for 24 hours. A solution of sodium meta-
bisulfite was then added and the mixture extracted with
dichloromethane (36100 mL). The combined organic layers
were dried (MgSO4), the solvents evaporated and the crude
product purified by column chromatography (eluting with 1 : 4
dichloromethane–petroleum ether). The product was recrystal-
lised from pentanol to give the title compound (0.49 g, 56%).
Mp 140 uC. Anal. Found: C 48.22; H 4.28; Br 43.07
(C30H32O2Br4 requires C 48.39; H 4.30; Br 43.01%); dH
(CDCl3, TMS, 300 MHz) 7.98 (2H, s), 7.89 (2H, s), 7.26 (2H,
s), 4.16 (4H, t, J~6.5), 2.03–1.94 (4H, m), 1.66–1.40 (12H, m),
0.99–0.95 (6H, m); dC (75.45 MHz; CDCl3) 155.1, 129.4, 127.9,
127.7, 126.9, 122.8, 122.5, 114.1, 104.7, 69.4, 31.7, 29.2, 25.9,
22.7, 14.1; m/z (FABMS) 744 (Mz, 50%).
2,3,6,11-Tetrakis(hexyloxy)-7,10-bis(hexylthio)triphenylene 4
Potassium tert-butoxide (5.00 g, 0.045 mol) was added to a
stirred solution of hexanethiol (5.25 g, 0.045 mol) in NMP
(30 mL). The solution was heated to 100 uC for 5 minutes and
then cooled to 70 uC. 2,11-Dibromo-3,6,7,10-tetrakis(hexyloxy)-
triphenylene 27 (3.50 g, 4.4561023 mol) was added and the
solution was stirred for 24 hours. 1-Bromohexane (3.00 g,
0.019 mol) was added and the mixture stirred at room
temperature for 24 hours. The reaction was worked up by
addition of water and the organic layer separated. The aqueous
layer was further extracted with diethyl ether (3650 mL). The
organic extracts were combined, washed with brine, dried
(Na2SO4) and the solvents evaporated. The crude product
was purified by column chromatography (eluting with 9 : 1
petroleum ether–dichloromethane) and recrystallised from
ethanol to give the title compound (1.22 g, 32%) as a colourless
solid.
dH (CDCl3, TMS, 300 MHz) 8.33 (2H, s), 7.86 (2H, s), 7.84
(2H, s), 4.28–4.22 (8H, m), 3.07 (4H, t, J~7.2), 1.99–1.90 (8H,
m), 1.78–1.71 (4H, m), 1.61–1.32 (36H), 0.96–0.85 (18H, m); dC
(75.45 MHz; CDCl3) 155.7, 149.6, 127.9, 125.9, 124.2, 123.4,
122.9, 107.4, 103.9, 69.6, 68.9, 32.2, 31.5, 31.4, 31.3, 29.2, 29.1,
28.8, 28.6, 25.7, 25.6, 22.5, 22.4, 13.9; m/z (FABMS) 861
(MzH, 100%); Acc. Mass (FAB) 861.5888 (C54H85O4S2
(MzH)~861.5889).
3,6-Bis(hexyloxy)-2,7,10,11-tetrakis(hexylthio)triphenylene 5
Potassium tert-butoxide (5.60, 0.050 mol) was added to a
stirred solution of hexanethiol (5.95 g, 0.050 mol) in NMP
(30 mL). The solution was heated to 100 uC for 5 minutes and
then cooled to 70 uC. 2,3,6,11-Tetrabromo-7,10-bis(hexyloxy)-
triphenylene 31 (2.50 g, 3.3661023 mol) was added and
the mixture stirred for 24 hours. 1-Bromohexane (2.50 g,
0.015 mol) was added and the reaction stirred for a further
24 hours at room temperature. The solution was worked up by
addition of water and the organic layer separated. The aqueous
layer was further extracted with diethyl ether (3650 mL). The
organic extracts were combined, washed with brine, dried
(Na2SO4) and the solvents evaporated. The crude product
was purified by column chromatography (eluting with 9 : 1
petroleum ether–dichloromethane) and recrystallised from
ethanol to give the title compound (0.98 g, 33%).
Anal. Found: C 72.62; H 9.52; S 14.38 (C54H84O2S4 requires
C 72.65; H 9.42; S 14.35%); dH (CDCl3, TMS, 300 MHz) 8.22
(2H, s), 8.20 (2H, s), 7.65 (2H, s), 4.27 (4H, t, J~6.5), 3.08 (8H,
m), 2.03–1.94 (4H, m), 1.83–1.73 (8H, m), 1.63–1.34 (36H, m),
0.98–0.90 (18H, m); dC (75.45 MHz; CDCl3) 156.3, 135.8,
128.5, 127.4, 127.0, 123.2, 123.0, 122.9, 103.9, 66.1, 33.9, 32.1,
31.8, 31.6, 29.3, 29.0, 28.9, 260, 22.7, 22.6, 14.1; m/z (FABMS)
893 (MzH, 100%).
1,2-Bis(4-hexyloxyphenyl)benzene 29
4-Hexyloxyphenylboronic acid 18 (8.47 g, 0.038 mol), 1,2-
dibromobenzene 28 (3.00 g, 0.013 mol), sodium carbonate
(6.36 g, 0.06 mol), palladium chloride (0.13 g, 7.1161024 mol)
and triphenylphosphine (0.38 g, 1.4461023 mol) were stirred
under reflux in a mixture of toluene, ethanol and water, (3 : 3 : 1,
200 mL) for 24 hours. The solvents were evaporated, water was
added and the mixture was extracted with dichloromethane
(46150 mL). The solvents were evaporated and the crude
product was purified by column chromatography (eluting
with 1 : 4 petroleum ether–dichloromethane), to give the title
compound as a colourless oil (3.80 g, 70%).
Anal. Found: C 83.61; H 8.92 (C30H38O2 requires C 83.72; H
8.84%); dH (CDCl3, TMS, 300 MHz) 7.36 (4H, m), 7.05 (4H, d,
J~8.8), 6.75 (4H, d, J~8.8), 3.91 (4H, t, J~6.6), 1.88–1.73
(4H, m), 1.55–1.30 (12H, m), 0.92–0.88 (6H, m, -C5H10CH3);
dC (75.45 MHz; CDCl3) 157.9, 140.2, 133.9, 130.8, 130.5, 127.0,
113.9, 67.8, 31.4, 29.1, 25.6, 22.4, 13.9; m/z (EI) 430 (Mz, 38%).
1,2-Bis(3-hexyloxyphenyl)benzene 32
3,6-Bis(hexyloxy)triphenylene 30
3-Hexyloxyphenylboronic acid 24 (11.30 g, 0.043 mol), 1,2-
dibromobenzene 28 (5.00 g, 0.018 mol), sodium carbonate
(8.80 g, 0.083 mol), palladium chloride (0.18 g, 9.846
1024 mol) and triphenylphosphine (0.53 g, 1.9761023 mol)
were stirred under reflux in a mixture of toluene, ethanol
and water (3 : 3 : 1, 200 mL) for 24 hours. The solvents were
evaporated and water was added. The mixture was extracted
with dichloromethane (46150 mL) and the solvents evapo-
rated. The crude product was purified by column chromato-
graphy (eluting with 1 : 4 petroleum ether–dichloromethane) to
give the title compound as a colourless oil (7.50 g, 82%).
1,2-Bis(4-hexyloxyphenyl)benzene 29 (1.83 g, 4.2561023 mol)
and iodine (1.08 g, 4.2561023 mol) were dissolved in ben-
zene (250 mL). The mixture was stirred and irradiated with
ultra-violet light at room temperature for 72 hours. Sodium
metabisulfite solution was added to the mixture and the organic
phase separated. The aqueous layer was further extracted with
dichloromethane (36100 mL) and the combined organic
phases were dried (MgSO4). The solvents were removed
in vacuo and the crude product purified by column chromato-
graphy (eluting with 4 : 1 petroleum ether–dichloromethane) to
give the title compound (1.09 g, 60%).
dH (CDCl3, TMS, 300 MHz) 7.45–7.37 (4H, m), 7.11 (2H, t,
J~7.8), 6.76–6.67 (6H, m), 3.73 (4H, t, J~6.6), 1.68–1.60 (4H,
m), 1.42–1.26 (12H, m), 0.92–0.87 (6H, m); dC (75.45 MHz;
CDCl3) 158.7, 142.9, 140.5, 130.4, 128.8, 127.5, 122.1, 115.7,
113.4, 67.8, 31.4, 28.9, 25.5, 22.5, 13.9; Acc. Mass (FAB)
431.2950 (C30H39O2 (MzH) requires 431.2950).
Mp 137 uC. Anal. Found: C 84.07; H 8.46 (C30H36O2
requires C 84.11; H 8.41%); dH (CDCl3, TMS, 300 MHz) 8.54
(4H, m, J~9.2), 7.95 (2H, s), 7.58–7.55 (2H, m), 7.25–7.29 (2H,
m), 4.19 (4H, t, J~6.6), 1.92–1.88 (4H, m), 1.59–1.36 (12H, m),
0.97–0.92 (6H, m); dC (75.45 MHz; CDCl3) 158.4, 130.9, 128.9,
J. Mater. Chem., 2001, 11, 2773–2783
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2,7-Bis(hexyloxy)triphenylene 33
(6.00 g, 0.056 mol), palladium chloride (0.06 g, 3.286
1024 mol) and triphenylphosphine (0.18 g, 6.8861024 mol)
were stirred under reflux in a mixture of toluene, ethanol
and water (3 : 3 : 1, 100 mL) for 48 hours. The solvents were
evaporated and water was added. The mixture was extracted
with dichloromethane (46100 mL). The crude product was
purified by column chromatography (eluting with 1 : 4 petro-
leum ether–dichloromethane) to give the title compound as a
colourless oil (3.40 g, 86%) which crystallised on standing.
Anal. Found: C 83.67; H 8.76 (C30H38O2 requires C 83.72; H
8.84%); dH (CDCl3, TMS, 300 MHz) 7.22–7.10 (10H, m), 6.95
(2H, s), 4.06 (4H, t, J~6.8), 1.89–1.80 (4H, m), 1.57–1.26 (12H,
m), 0.93–0.88 (6H, t, J~6.9); dC (75.45 MHz; CDCl3) 148.5,
141.6, 133.2, 129.9, 127.8, 126.2, 116.2, 69.4, 31.4, 29.2, 25.6,
22.5, 13.8; m/z (EI) 430 (Mz, 50%).
1,2-Bis(3-hexyloxyphenyl)benzene 32 (5.0 g, 0.012 mol) was
stirred in dichloromethane (200 mL) at room temperature.
Iron(III) chloride (3.80 g, 0.023 mol) was added and the mix-
ture stirred for a further two hours. Methanol and water
were then added and the mixture extracted with dichloro-
methane (36100 mL). The combined organic layers were dried
(MgSO4) and the solvents were evaporated. Purification of the
crude product by column chromatography (eluting with 1 : 4
dichloromethane–petroleum ether) gave the title compound
(3.38 g, 68%) as a cream powder.
Mp 102.5 uC. Anal. Found: C 84.03; H 8.46 (C30H36O2
requires C 84.11; H 8.41%); dH (CDCl3, TMS, 300 MHz) 8.56
(2H, m), 8.43 (2H, d, J~9.0), 8.01 (2H, d, J~2.3), 7.43 (2H,
m), 7.23 (2H, dd, J~9.0 and 2.3), 4.16 (4H, t, J~6.6), 1.90–
1.83 (4H, m), 1.57–1.375 (12H, m), 0.96–0.91 (6H, t, J~7.0); dC
(75.45 MHz; CDCl3) 158.0, 130.3, 130.2, 127.2, 124.5, 124.1,
123.6, 116.5, 106.8, 68.4, 31.7, 29.5, 25.9, 22.7, 14.1; m/z (EI)
428 (Mz, 80%).
2,3-Bis(hexyloxy)triphenylene 37
1,2-Bis(hexyloxy)-3,4-diphenylbenzene 35 (1.50 g, 6.906
1023 mol) and iodine (1.08 g, 4.2561023 mol) were dissolved
in benzene (250 mL). The mixture was stirred and irradiated
with ultra-violet light at room temperature for 72 hours.
Sodium metabisulfite solution was added to the mixture and
the organic phase separated. The aqueous layer was extracted
with dichloromethane (36100 mL) and the combined organic
phases dried (MgSO4). The solvent was evaporated and the
crude product purified by column chromatography (eluting
with 4 : 1 petroleum ether–dichloromethane) to give the title
compound (0.85 g, 57%).
Mp 123 uC. Anal. Found: C 84.09; H 8.48 (C30H36O2
requires C 84.11; H 8.41%); dH (CDCl3, TMS, 300 MHz) 8.66
(2H, m), 8.50 (2H, m), 8.03 (2H, s), 7.65–7.26 (4H, m), 4.25
(4H, t, J~6.6), 1.98–1.93 (4H, m), 1.60–1.38 (12H, m), 0.96–
0.85 (6H, t, J~7.0); dC (75.45 MHz; CDCl3) 150.1, 132.4,
129.4, 128.4, 127.8, 124.5, 123.6, 123.1, 106.5, 69.4, 31.7, 29.4,
25.9, 22.7, 14.1; m/z (EI) 428 (Mz, 100%).
2,3,7,10-Tetrabromo-6,11-bis(hexyloxy)triphenylene 34
2,7-Bis(hexyloxy)triphenylene 33 (1.76 g, 4.1161023 mol) was
stirred in dichloromethane (10 mL) at room temperature.
Bromine (6.57 g, 0.04 mol) was added and the solution stirred
for 24 hours. A solution of sodium metabisulfite was added and
the mixture was extracted with dichloromethane (36100 mL).
The combined organic layers were dried (MgSO4) and the
crude product was purified by column chromatography
(eluting with 1 : 4 dichloromethane–petroleum ether). The
product was recrystallised from pentanol to give the title
compound (2.08 g, 68%).
Mp 180 uC. Anal. Found: C 48.51; H 4.30; Br 42.89
(C30H32O2Br4 requires C 48.39; H 4.30; Br 43.01%); dH
(CDCl3, TMS, 300 MHz) 8.06 (2H, s), 7.89 (2H, s), 7.10 (2H,
s), 4.06 (4H, t, J~6.4), 1.99–1.92 (4H, m), 1.64–1.42 (12H, m),
0.99–0.95 (6H, m); dC (75.45 MHz; CDCl3) 154.1, 128.9, 127.4,
127.1, 126.8, 123.3, 122.9, 114.3, 104.2, 69.2, 31.5, 29.0, 25.6,
22.5, 13.9; m/z (FABMS) 744 (Mz, 100%).
2,3-Bis(hexyloxy)-7,10-dichlorotriphenylene 36
1,2-Bis(hexyloxy)-3,4-diphenylbenzene 35 (3.80 g, 8.8561023
mol) was stirred in dichloromethane (300 mL) at room
temperature. Iron(III) chloride (45.0 g, 0.27 mol) was slowly
added and the solution stirred for two hours. The reaction
mixture was then cooled (ice–salt bath) and methanol (100 mL)
carefully added with stirring. The solvents were evaporated and
dichloromethane was added to the residue. The organic phase
was washed with water and the aqueous layer extracted with
dichloromethane (36150 mL). The solvent was evaporated to
give a brown solid which was purified by column chromato-
graphy (eluting with 4 : 1 petroleum ether–dichloromethane) to
give the title compound (2.24 g, 51%).
Mp 127 uC. Anal. Found: C 72.19; H 6.87; Cl 14.25
(C30H34O2Cl2 requires C 72.43; H 6.89; Cl 14.25%); dH
(CDCl3, TMS, 270 MHz) 8.36 (2H, d, J~2.0), 8.28 (2H, d,
J~8.9), 7.81 (2H, s), 7.53 (2H, dd, J~8.9, 2.0), 4.21 (4H, t,
J~6.6), 1.98–1.89 (4H, m), 1.61–1.55 (4H, m), 1.44–1.38 (8H,
m), 0.93 (6H, t, J~7.0); dC (67.94 MHz; CDCl3) 149.6, 131.9,
128.9, 127.9, 127.3, 124.0, 123.0, 122.6, 105.9, 77.3, 76.9, 76.4,
69.1, 31.5, 29.1, 25.7, 22.5, 13.9; m/z (FABMS) 495 (MzH,
100%).
2,7-Bis(hexyloxy)-3,6,10,11-tetrakis(hexylthio)triphenylene 6
Potassium tert-butoxide (6.77, 0.060 mol) was added to a
stirred solution of hexanethiol (4.13 g, 0.060 mol) in NMP
(30 mL). The solution was heated to 100 uC for 5 minutes and
then cooled to 70 uC. 2,3,7,10-Tetrabromo-6,11-bis(hexyloxy)-
triphenylene 34 (3.00 g, 4.0361023 mol) was added and
the solution stirred for 48 hours. 1-Bromohexane (2.80 g,
0.016 mol) was added and the reaction stirred for 24 hours at
room temperature. The solution was worked up by addition of
water and the organic layer separated. The aqueous layer was
further extracted with diethyl ether (36100 mL). The organic
extracts were combined, washed with brine, dried (Na2SO4)
and the solvent evaporated. The crude product was purified by
column chromatography over silica gel (eluting with 9 : 1
petroleum ether–dichloromethane) and recrystallised from
ethanol to give the title compound (1.13 g, 38%).
Anal. Found: C 72.72; H 9.38; S 14.00 (C54H84O2S4 requires
C 72.65; H 9.42; S 14.35%); dH (CDCl3, TMS, 300 MHz) 8.33
(2H, s), 8.26 (2H, s), 7.78 (2H, s), 4.27 (4H, t, J~6.4), 3.11–3.06
(8H, m), 1.99–1.94 (4H, m), 1.82–1.73 (8H, m), 1.63–1.25 (36H,
m), 0.97–0.83 (18H, m); dC (75.45 MHz; CDCl3) 155.8, 136.5,
128.0, 127.6, 127.2, 123.9, 123.7, 122.7, 103.9, 69.0, 34.1, 32.1,
31.7, 31.6, 31.5, 29.8, 29.3, 29.0, 28.9, 25.9, 22.7, 22.6, 22.5,
14.1; m/z (FABMS) 892 (M, 65%).
2,3-Bis(hexyloxy)-1,4-dibromo-7,10-dichlorotriphenylene 39
2,3-Bis(hexyloxy)-7,10-dichlorotriphenylene 36 (1.00 g, 2.016
1023 mol) was stirred in dichloromethane (100 mL) and
bromine (1.60 g, 0.01 mol) was added. The mixture was stirred
at room temperature for 2 hours. Sodium metabisulfite
solution was added and the organic phase separated. The
aqueous layer was further extracted with dichloromethane
(36100 mL) and the combined organic phases were dried
(MgSO4). The solvent was removed in vacuo and the crude
1,2-Bis(hexyloxy)-3,4-diphenylbenzene 35
Phenylboronic acid 10 (4.20 g, 0.034 mol), 1,2-dibromo-4,5-
bis(hexyloxy)benzene 15 (5.00 g, 0.012 mol), sodium carbonate
2782
J. Mater. Chem., 2001, 11, 2773–2783

View Article Online
3
4
H. Eichhorn, J. Porphyrins Phthalocyanines, 2000, 4, 88.
product purified by column chromatography (eluting with 1 : 1
petroleum ether–dichloromethane) to give the title compound
(0.93 g, 70%).
N. Boden and B. Movaghar, in Handbook of Liquid Crystals, eds.
D. Demus, J. Goodby, G. W. Gray, H.-W. Spiess and V. Vill,
Wiley-VCH, Weinheim, 1998, Vol. II, p. 781.
Mp 169 uC. Anal. Found: C 54.66; H 4.79; Cl 10.77; Br 23.83
(C30H32O2Cl2Br2 requires C 54.99; H 4.92; Cl 10.82; Br
24.39%); dH (CDCl3, TMS, 270 MHz) 9.05 (2H, d, J~8.9),
8.25 (2H, d, J~2.0), 7.46 (2H, dd, J~8.9 and 2.0), 4.11 (4H, t,
J~6.6), 1.98–1.82 (4H, m), 1.60–1.48 (4H, m), 1.40–1.24 (8H,
m), 0.94–0.89 (6H, m); dC (67.94 MHz; CDCl3) 150.3, 133.7,
130.7, 129.1, 128.9, 127.6, 126.4, 122.8, 113.3, 74.1, 31.5, 30.1,
25.6, 22.5, 13.9; m/z (EI) 652.9 (Mz, 100%).
5
D. Adam, F. Closs, T. Frey, D. Funhoff, D. Haarer, H. Ringsdorf,
P. Schuhmacher and K. Siemensmeyer, Phys. Rev. Lett., 1993, 70,
457.
B. Kohne, W. Poules and K. Praefcke, Chem. Zeit., 1984, 108, 113.
E. F. Gramsbergen, H. J. Hoving, W. H. de Jeu, K. Praefcke and
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6
7
8
9
2,3-Bis(hexyloxy)-7,10-bis(hexylthio)triphenylene 40
10 A. M. van der Craats, M. P. de Haas and J. M. Warman, Synth.
Met., 1997, 86, 2125.
11 A. M. van der Craats, J. M. Warman, M. P. de Haas, D. Adam,
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823.
Potassium tert-butoxide (1.35 g, 0.012 mol) was added to a
stirred solution of hexanethiol (1.42 g, 0.012 mol) in NMP
(20 mL). The solution was heated to 100 uC for 5 minutes and
then cooled to 70 uC. 2,3-Bis(hexyloxy)-7,10-dichlorotripheny-
lene 36 (1.00 g, 2.0161023 mol) was added and the solution
was stirred for 2 hours. 1-Bromohexane (2.80 g, 0.016 mol)
was added and the reaction stirred for 24 hours at room
temperature. The solution was worked up by addition of water
and the organic layer separated. The aqueous layer was
extracted with diethyl ether (36100 mL). The organic extracts
were combined, washed with brine, dried (Na2SO4) and the
solvent evaporated. The crude product was purified by column
chromatography (eluting with 4 : 1 petroleum ether–dichloro-
methane) and recrystallised from ethanol to give the title
compound (0.69 g, 52%).
Mp 77 uC. Anal. Found: C 76.34; H 9.18; S 9.61 (C42H60O2S2
requires C 76.31; H 9.15; S 9.70%); dH (CDCl3, TMS,
270 MHz) 8.47 (2H, d, J~1.7), 8.31 (2H, d, J~8.9), 7.88
(2H, s), 7.56 (2H, dd, J~8.9, 1.7), 4.20 (4H, t, J~6.6), 3.07
(4H, t, J~7.3) 1.96–1.90 (4H, m), 1.75–1.69 (4H, m), 1.59–1.27
(24H, m), 0.96–0.86 (12H, m); dC (67.94 MHz; CDCl3) 149.3,
134.5, 128.7, 128.1, 127.7, 123.6, 123.2, 106.3, 69.1, 34.0, 31.4,
31.3, 29.1, 28.4, 25.6, 22.5, 22.4, 13.9; m/z (FABMS) 660 (M,
100%).
12 B. Kohne, K. Praefcke, T. Derz, W. Frischmuth and C. Gansau,
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13 F. Closs, L. Ha¨ussling, P. Henderson, H. Ringsdorf and
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14 S. Kumar and M. Manickam, Synthesis, 1998, 1119.
15 W. Kreuder and H. Ringdorf, Makromol. Chem., Rapid Commun.,
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16 G. Cooke, F. Hell and S. Violini, Synth. Commun., 1997, 27, 3745.
17 P. T. Wright, I. Gillies and J. D. Kilburn, Synthesis, 1997, 1007.
18 M. T. Allen, S. Diele, K. D. M. Harris, T. Hegmann, B. M. Kariuki,
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19 P. Henderson, S. Kumar, J. A. Rego, H. Ringsdorf and
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20 J. A. Rego, S. Kumar, I. J. Dmochowski and H. Ringsdorf, Chem.
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21 N. Boden, R. J. Bushby and A. N. Cammidge, J. Chem. Soc.
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22 N. Boden, R. J. Bushby, A. N. Cammidge and G. Headdock,
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23 N. Boden, R. J. Bushby and A. N. Cammidge, J. Am. Chem. Soc.,
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24 R. C. Borner and R. F. W. Jackson, J. Chem. Soc., Chem.
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25 J. W. Goodby, M. Hird, K. J. Toyne and T. Watson, J. Chem.
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27 N. Miyaura and A. Suzuki, Chem. Rev., 1995, 95, 2457.
28 N. Boden, R. J. Bushby, A. N. Cammidge and M. V. Jesudason,
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Acknowledgements
We thank the Association of Commonwealth Universities and
UEA for funding (HG) and the EPSRC Mass Spectrometry
Service Centre at Swansea.
29 B. Rose and H. Meier, Z. Naturforsch., Teil B, 1998, 53, 1031.
30 N. Boden, R. J. Bushby, A. N. Cammidge and G. Headdock,
Tetrahedron Lett., 1995, 36, 8685.
31 For a recent example of spontaneous homeotropic alignment
in a columnar phthalocyanine see K. Hatsusaka, K. Ohta,
I. Yamamoto and H. Shirai, J. Mater. Chem., 2001, 11, 423.
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