Redox-driven molecular switches consisting of bis(benzodithiolyl)bithienyl scaffold and mesogenic moieties: Synthesis and complexes with liquid crystalline polymer

Article abstract of DOI:10.1021/jo501072u

Molecular switches composed of a benzodithiolylbithienyl scaffold and biphenyl or terphenyl mesogenic substituents were designed and synthesized. The molecular switches could undergo redox-triggered interconversion between the cationic form and cyclized n

Full text of DOI:10.1021/jo501072u

Article
pubs.acs.org/joc
Redox-Driven Molecular Switches Consisting of
Bis(benzodithiolyl)bithienyl Scaffold and Mesogenic Moieties:
Synthesis and Complexes with Liquid Crystalline Polymer
Toshihiro Ohtake,* Hideki Tanaka, Tetsuro Matsumoto, Mutsumi Kimura, and Akira Ohta*
,†
†
†
§
,‡
†
Seiko Epson Corporation, 281 Fujimi, Fujimi-machi, Suwa-gun, Nagano 399-0293, Japan
‡
Department of Chemistry, Faculty of Science, Shinshu University, Matsumoto, Nagano 390-8621, Japan
§
Division of Chemistry and Materials, Faculty of Textile Science and Technology, Shinshu University, Ueda, Nagano 386-8567, Japan
S Supporting Information
*
ABSTRACT: Molecular switches composed of a benzodi-
thiolylbithienyl scaffold and biphenyl or terphenyl mesogenic
substituents were designed and synthesized. The molecular
switches could undergo redox-triggered interconversion
between the cationic form and cyclized neutral form, and
this was confirmed using cyclic voltammetry and UV−vis
spectroscopy. Binary complexes consisting of the molecular switches and a liquid crystalline polymer (LCP) were prepared to
investigate the function of these redox-active molecular switches as actuating dopants. X-ray diffraction measurements were
performed to determine the differences between the layer spacings of the complexes in the liquid crystalline phase with the
oxidized and reduced states of the molecular switches. The LCP that was doped with the oxidized cationic form of the molecular
switch had layer spacings that were up to 4% larger than the layer spacings in the polymer that was doped with the reduced
cyclized molecular switch. Our approach will allow stimulus-responsive deformable materials to be constructed and give an
impetus for fabricating redox-driven soft actuators.
INTRODUCTION
the properties of LCs have been developed using polymers and
gels. Liquid crystalline elastomers (LCEs) and liquid crystalline
polymer (LCP) gels are materials that can change shape and
combine the anisotropic properties of LCs with the properties
■
1
Molecular switches, or molecular machines, undergo a
structural change when an external stimulus, such as a change
2
−4
5−12
in pH,
the presence of light,
an ionic interaction,
an electrochemical
or a chemical treat-
39
1
3−24
25,26
of cross-linked rubber-like polymers and gels. The changes in
the shapes of LCEs and LCP gels are, in most cases, driven by
reaction,
2
7
ment, is applied. There has been much interest in using
molecular switches to prepare novel actuating or sensing
materials. The assembly and operation of stimulus-responsive
molecules in an ordered molecular field is required to develop
their performance in terms of deformation and stress. Ordered
4
0−42
43−47
phase transitions,
field.
photoisomerization,
or electric
3
7,48−50
However, a few examples of redox responsive
51
LC molecules have been reported, although, from the
practical point of view, electrochemically controlled actuating
systems have advantages that include low operating voltages
and precise control.
2
8
molecular architecture plays a key role in biological systems
that exhibit specific and amplified functions, a typical example
2
9
We have attempted to prepare redox-driven molecular
switches that are capable of propagating their conformational
changes to the surrounding polymer matrix, causing enhanced
changes in their ordered nanostructures. This would be a
promising method of constructing redox-driven deformable
materials. We have previously reported the electrochemically
mediated conformational interconversion of bis(benzo-
being myosin II, which plays a role in muscle contraction.
well-ordered structure is crucial to the production of synthetic
A
3
0,31
32,33
sensing
or actuating systems.
We have focused our attention on the unique nature of liquid
crystals (LCs) for forming well-ordered molecular fields. LCs
have recently become widely known as functional materials that
3
4,35
form self-assembled highly ordered anisotropic structures.
52
dithiolyl)bithienyl (BDTBT), as shown in Scheme 1. An
electrochemical stimulus can induce C−C bonds to form or
break, through an electron transfer mechanism. Similar redox-
driven interconversion have been studied by Yamashita et al.
Using LCs will allow to gain insights into how novel
intrinsically anisotropic soft actuators can be fabricated. The
utilization of the stimulus-induced changes of the ordered
structures of liquid crystals has a potential to achieve stimulus-
triggered deformable materials. Previously, controls of the layer
spacings of smectic liquid crystals driven by photoisomerization
13−18
and Suzuki et al.
In this study, we designed functional
molecular switches 1, 2, and 3, which were based on a
36
of azobenzene unit, tilting of directors by electroclinic
3
7
38
effect, and molecular reorientation by phase transition
have been reported. A wide variety of soft actuators based on
Received: May 16, 2014
©
XXXX American Chemical Society
A
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a
Scheme 1. Redox-Triggered Structural Interconversion of
Bis(benzodithiolyl)bithienyl
Scheme 3. Synthesis of Mesogenic Units
benzodithiolylbithienyl scaffold and rigid terphenyl or biphenyl
substituents (mesogenic moieties). These molecular switches
could undergo redox-triggered C−C bond forming and bond
breaking reactions. We wished to evaluate the functions of
these molecular switches as dopants for inducing changes in the
molecular order of surrounding molecules, and, to achieve this,
we designed a side-chain LCP to act as a host polymer.
Complexes of the molecular switches 1−3 with LCP were then
prepared (Scheme 2). Pure LCP formed a smectic ordered
structure and was suitable for evaluating the differences in the
smectic ordered structures when it was complexed with the
molecular switches. Here, we report the synthesis, electro-
chemical response, and liquid crystalline properties of the
redox-driven molecular switches 1−3 and the results of
examination of the nanostructures of the molecular switch/
LCP complexes in the oxidized and reduced states.
a
Reagents and conditions: (a) 1-bromooctane, K CO , acetone, reflux;
2
3
RESULTS AND DISCUSSION
(b) 2,3-difluorophenylboronic acid, Pd(PPh ) , Na CO , DME/
3 4 2 3
■
EtOH/H O, reflux; (c) (1) butyllithium, B(OMe) , THF, −78 °C;
2
3
Synthesis and Characterization. The mesogenic units
and bis(benzodithiolyl)bithienyl moiety were prepared sepa-
rately, then they were attached to each other using either
Suzuki−Miyaura coupling reaction or Wiliamson etherification
reaction. Laterally fluorinated biphenyl or terphenyl were used
as the mesogenic units. The presence of lateral fluorine
substituents would be expected to decrease the melting point of
(
2) HCl; (d) 4-bromophenol, Pd(PPh ) , Na CO , DME/EtOH/
3 4 2 3
H O, reflux; (e) 1-bromo-4-iodobenzene, Pd(PPh ) , Na CO ,
2
3
4
2
3
benzene/EtOH/H O, 95 °C; (f) (Bpin) , PdCl (dppf), KOAc,
2
2
2
DMF, 80 °C; (g) 8-bromo-1-octanol, K CO , KI, DMF, 80 °C; (h)
2
3
TsCl, Et N, CH Cl , rt.
3
2
2
53
the mesogenic unit, which should offer practical advantages.
Scheme 3 shows the synthetic route for the mesogenic units,
which were synthesized from 4-bromophenol. The alkylation of
Suzuki−Miyaura coupling reaction, to give biphenyl 5. After 5
had been converted to the corresponding boronic acid 6, cross-
55
coupling of 6 with 1-iodo-4-bromobenzene or 4-bromophe-
nol afforded 7 or 9, respectively. Terphenyl 7 was transformed
4
-bromophenol by butyl bromide in the presence of potassium
carbonate afforded 1-bromo-4-butoxybenzenes 4, which was
then coupled with 2,3-difluorophenylboronic acid, using the
54
56
into the corresponding boronate 8. Attempts to prepare the
boronic acid from 7 through lithiation or using the Grignard
Scheme 2. Chemical Structures of Molecular Switches (Dopants) and Host Liquid Crystalline Polymer (LCP)
B
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5
7
reaction were not successful. An alkylene spacer was
toluenesulfonic acid, to afford 19, 20, and 21, respectively.
The oxidation of 19, 20, and 21 with 4 equiv of (p-
58
incorporated into 9, then the corresponding tosylate 11 was
obtained by treating 10 with tosyl chloride in the presence of
triethylamine.
The synthetic route used to prepare the bithienyl moiety is
+
•
−
BrC H ) N SbCl yielded the corresponding SbCl6 salts
6
4 3
6
5
9
2+ 2+
2+
1 , 2 , and 3 . The reductive cyclization of these SbCl salts
6
using zinc gave cyclized compounds 1, 2, and 3.
6
0,61
2+
2+
2+
shown in Scheme 4. Dialdehyde 12
was used as a starting
The dications 1 , 2 , and 3 were also obtained, in
moderate yields, from the chemical oxidation of 1, 2, and 3,
respectively, with 2 equiv of (p-BrC H ) N SbCl (Scheme
6 4 3 6
a
+•
−
Scheme 4. Synthesis of Bithienyl Moiety
6
). This confirmed that the redox-triggered interconversion
between the cyclic form and dicationic form was reversible.
Scheme 6. Structural Interconversion between Oxidized and
Reduced Forms through Chemical Treatment
a
UV−vis spectra of the molecular switches and their
corresponding dications, in dichloromethane, are shown in
Figure 1. Characteristic absorption bands corresponding to
π−π* electronic transitions in the aromatic cores were
observed in the UV region for the molecular switches 1, 2,
and 3 (Figure 1A). The maximum absorption (λmax) of 1 was
found at 292 nm, and this was higher than that found for 2
(λmax = 279 nm) or 3 (λmax = 287 nm). This may have been
caused by the extension of the π-conjugation system. However,
Reagents and conditions: (a) ethylene glycol, TsOH, benzene, reflux;
(
b) (1) butyllithium, THF, −78 °C; (2) DMF; (3) HCl; (c) NaBH4,
EtOH, rt.
material for preparation of diol 15. The carbonyl groups in 12
were protected with ethylene glycol to form 13, then 13 was
formylated by treating it with BuLi followed by DMF, to give
1
4, which was then reduced by the treating it with NaBH in
4
2
+
2+
ethanol, to afford diol 15.
new absorption bands close to 450 nm were found for 1 , 2 ,
and 32+ (Figure 1B). The hypochromic effect could be seen
close to 300 nm when 1 and 2 were oxidized to their
corresponding dications, but no such effect was seen for 3. The
absorption edges in the visible region were 512, 634, and 663
The mesogenic moieties were incorporated into the
benzodithiolyl moiety as shown in Scheme 5. The biphenyl
derivative 6 and terphenyl derivative 8 were directly attached to
dialdehyde 12, through palladium-catalyzed cross-coupling
reactions, to give 17 and 16, respectively. However, the
preparation of 18, in which the terphenyl units are connected
to the bithienyl moiety through alkylene spacers, was achieved
by conventional etherification. We incorporated the benzo-
dithiolyl units through condensation of the dialdehydes 16, 17,
and 18 with 1,2-benzenedithiol in the presence of p-
2
+
2+
2+
nm for 3 , 1 , and 2 , respectively. A noticeable red shift was
2+
2+
observed for the absorption edges of 1 and 2 relative to the
absorption edge for 3 .
2+
62
As shown in Figure 2A, 1 had the longest conjugated π-
bonds (consisting of terphenyl units and thiophene ring), 2 had
π-conjugation over the biphenyl units and thiophene ring, and
a
Scheme 5. Synthesis of Molecular Switches 1, 2, and 3
a
Reagents and conditions: (a) 8, PdCl (dppf), Na CO , DMF/H O, 95 °C; (b) 6, Pd(PPh ) , Na CO , DME/EtOH/H O, reflux; (c) (1) 11, NaH,
2
2
3
2
3
4
2
3
2
+
•
−
DMF, 75 °C; (2) HCl; (d) 1,2-benzenedithiol, TsOH, benzene, reflux; (e) 4 equiv of (p-BrC H ) N SbCl , MeCN/CH Cl , rt; (f) Zn, MeCN/
6
4
3
6
2
2
THF, rt; (g) Zn, CH Cl /THF, rt.
2
2
C
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lized from a CH Cl /methanol solution by slow evaporation
2
2
(
̅
Figure 3). The crystals of 2 crystallized in the space group P1.
Figure 3. ORTEP view of 2. Hydrogen atoms are omitted for clarity.
The lower occupancy disordered fluorine atoms are shown in light
green.
Both 2,3-difluorophenylene rings were statistically disordered
by 180° rotation in the crystal. The dihedral angle of the
bithienyl moiety in 2 was 27.1°, which is much larger than that
52
of the unsubstituted 1,1′-benzodithiolyl bithienyl (8.3°) and
18
oligothiophene derivative (1.4°), suggesting that the biphenyl
mesogenic unit that was incorporated caused the bithienyl
moiety conformation to be more twisted than it was in the
unsubstituted molecule. The C−C bond formed through
electrochemical reduction reaction was 1.577(4) Å long,
which is approximately the length we found previously
Figure 1. UV−vis spectra for (A) the molecular switches and (B) their
2+
dications (SbCl salts) in dichloromethane. The spectra for 1 and 1
6
2+
2+
are in blue, for 2 and 2 in red, and for 3 and 3 in green.
52
3
had π-conjugation over terphenyl units. The increasing π-
(1.583(3) Å).
bond conjugation length order matched the increasing λmax
order. The bathochromic shift in the absorption maximum
when the π-conjugation was lengthened was confirmed for our
molecular switches. The longer absorption edge wavelengths
Electrochemical Studies. The electrochemical behaviors
of the cyclized compounds 1, 2, and 3 were examined using
cyclic voltammetry (CV). CV analyses were performed in
PhCN, with Bu NBF as the supporting electrolyte, on a Pt
4
4
for 12 and 2 than for 3 could be attributed to the extension
of the π-conjugation system in the dications through the direct
attachment of the terphenyl or biphenyl units to the thiophene
ring (Figure 2B). The π-conjugation system in 32+ was
interrupted between the terphenyl unit and thiophene ring
because of the presence of the alkylene spacer, but this had no
effect on the absorption properties.
+
2+
2+
button electrode. Figure 4 shows CV results for the cyclized
compounds. Similar redox curves were obtained for all the
compounds, with oxidation peaks at approximately 1.3 V and
52
reduction peaks at 0.1 V. According to our previous results,
the oxidation peaks could be attributed to the oxidative bond-
breaking process involving the cyclized compounds, and the
reduction peaks could be attributed to reductive C−C bond-
forming in the dications. CV results from the analyses
confirmed that the same reversible bond-breaking and bond-
forming reactions were driven by the electrochemical process.
The electrochemical properties of 1, 2, and 3 are summarized in
Table 1. No distinct differences were found between the Epa
We attempted to investigate the structures of the molecular
switches using X-ray crystallography. Single crystals suitable for
X-ray crystallography were obtained only for 2. Attempts to
prepare single crystals of 1 and 3 were not successful. Single
crystals of 2 suitable for X-ray crystal analysis were recrystal-
Figure 2. π-conjugation systems determined from UV−vis spectra (red indicates cyclized molecules and blue indicates the corresponding dications).
2+
2+
2+
(
A) Cyclized molecules 1, 2, and 3. (B) Dications 1 , 2 , and 3 .
D
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Figure 4. Cyclic voltammograms for (a) 1, (b) 2, and (c) 3 in
benzonitrile solution containing 0.1 M Bu NBF . The scan rate was
4
4
Figure 5. (A) UV−vis spectra of 2 in CH Cl solution containing 0.1
2
2
100 mV/s.
M Bu NBF as a function of the applied potential, from 0.0 to 1.40 V,
4
4
2+
against SCE. (B) UV−vis spectra of 2 in CH Cl solution containing
.1 M Bu NBF as a function of the applied potential, from 0.40 to
a
2
2
Table 1. Redox Potentials of 1, 2, and 3
0
4 4
b
c
0.05 V, against SCE.
compound
Epa (V)
Epc (V)
1
2
3
+1.33
+1.37
+1.37
+0.13
+0.19
+0.08
and opened dicationic form occurred and also confirm that
mesogenic moieties being attached to the thiophene ring did
not prevent the redox-triggered interconversion, as was
a
Peak potentials in V versus SCE; electrolyte: 0.1 M Bu NBF ;
solvent: PhCN; Pt electrode, scan rate: 100 mV/s. Anodic peak
potentials of 1, 2, and 3. Cathodic peak potentials of 1 , 2 , and 3 .
4
4
b
52
observed for BDTBT.
c
2+ 2+
2+
Mesomorphic Behavior. The mesomorphic behaviors of
the cyclized compounds were examined using differential
scanning calorimetry, X-ray diffractometry (XRD), and
polarized optical microscopy. Compound 3 only exhibited
liquid crystalline phases, whereas 1 and 2 did not show any
mesophases. A focal conic fan texture, which is a characteristic
of a smectic phase, a striated texture (Figure 6A), and a
schlieren texture typical of a nematic phase (Figure 6B) were
observed. It should be noted that incorporating the alkyl spacer
to connect the mesogenic moieties and bithienyl scaffold played
an important role in the formation of stable liquid crystalline
phases.
values for the compounds, and the values were close to that for
52
the unsubstituted parent molecule (1.33 V). However, the
Epcs varied between 0.08 and 0.19 V. The Epc for 3 was
distinctly lower than that for the unsubstituted parent molecule
(
0.16 V), suggesting that the oxidized dication 32+ was
stabilized by being attached to the electron donating alkylene
spacer. Another redox couple at 1.56 V was observed only for 3.
A similar redox couple was found for the dialdehyde 18, which
contained mesogenic moieties (Figure S1, Supporting
Information). This could be attributed to the redox response
of the mesogenic moieties.
Spectroelectrochemical measurements were also performed,
to determine the electrochemical response. All redox pairs
clearly showed electrochromism. Figure 5 shows the changes in
the absorption spectra of 2 in CH Cl as the applied potential
was changed. Oxidation caused absorption in the UV region to
decrease and new absorption peaks in the visible region to
simultaneously develop (Figure 5A), and the opposite spectral
changes were found when the samples were reduced (Figure
For the SbCl salts of these compounds, a birefringent
6
2
+
−
mesophase (Figure 6C) could be seen only for 3 (SbCl ) ,
6 2
but we could not identify the type of liquid crystalline phase
that was present. Ionic compounds that exhibit liquid crystalline
phases have previously been intensively studied as ionic liquid
2
2
6
3−65
64
crystals.6
The ionic parts, in either rigid cores or flexible
5
spacers, can contribute to the formation of ordered structures
in liquid crystalline phases. The ionic parts of the benzodithiolyl
moieties may have had an effect on the mesomorphism of
2+
−
5
B). The isosbestic point at 302 nm indicates clean
3 (SbCl ) in our study.
6 2
2
+
transformation between 2 and 2 . Similar spectral changes
were observed for 1 and 3 (Figures S2 and S3, Supporting
Information). These results support the conclusion that
structural interconversion between the reduced cyclic form
The nanostructure of 3 in the liquid crystalline phase was
examined using XRD. Figure 7 shows the XRD patterns for 3 at
89 °C (Figure 7A) and 70 °C (Figure 7B) during cooling. A
sharp diffraction peak at 2θ = 4.09° (d = 21.6 Å) and broad
E
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Figure 7. X-ray diffraction patterns for 3 at (A) 89 °C, (B) 70 °C
during cooling, and (C) the possible packing structures for 3 in
smectic E (crystal E) phase. The directors of 3 in the unit cell are
drawn in the same direction for clarity.
packing of 3 in this mesophase was determined from these
XRD results and is illustrated schematically in Figure 7C. As
66−68
previously reported,
the smectic phase with a rectangular
lattice structure that was observed for 3 could be identified as a
smectic E (crystal E) phase.
Nanostructures of Molecular Switch/LCP Complexes.
The nanostructures of the molecular switch/LCP complexes in
liquid crystalline states were analyzed by XRD to assess the
abilities of the molecular switches to change the ordered
structures of the host polymers. Feringa et al. recently
demonstrated that the ordered structure of host cholesteric
liquid crystalline molecules could be photochemically tuned by
Figure 6. Polarized photomicrographs of (A) 3 at 102 °C on heating;
2+
−
(
B) 3 at 118 °C on heating; and (C) 3 (SbCl ) at 127 °C on
6 2
cooling. The scale bar indicates 50 μm.
halo around 2θ = 20°, which are characteristics of a one-
dimensional lamellar structure of a smectic A phase, were
observed at 89 °C. The broad halo around 20° may have been
caused by melting of the alkyl spacer. The XRD pattern for 3 at
69
doping with a photoresponsive molecular rotor. In that case,
the conformational change in the molecular rotor caused the
ordered structure of the host LC molecules to change because
of strong host−guest interactions. Other successful examples of
orientations of host LCs and the helical structures and helical
twisting powers of cholesteric LCs being controlled by
photoresponsive molecular switches have also been re-
7
1
4
0 °C had seven diffraction peaks, at 27.5, 21.3, 21.0, 16.6, 14.0,
2.0, and 10.6 Å (Figure 7B inset). The lattice parameters a =
2.6 Å and b = 36.1 Å were calculated assuming that the peaks
at 27.5, 21.3 Å, and 21.0 Å were (110), (200), and (001)
reflections, respectively, and the other four diffraction peaks
were assigned to (120), (300), (030), and (400) reflections for
a two-dimensional rectangular lattice. The possible molecular
70,71
ported.
Inspired by the above-mentioned studies, we
expected that our redox-driven molecular switches could induce
changes in the local order of the host polymer. Host polymeric
F
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a
materials or functional gels that could undergo macroscopic
deformations could be achieved if such structural changes could
be effectively enhanced.
Table 2. Layer Spacings of Complexes of LCP with
Molecular Switches and Their SbCl Salts in Smecic A
6
Phases
The host polymer LCP was prepared by conventional radical
polymerization of 22, as shown in Scheme 7. Complexes
b
complex
Pure LCP
1/LCP
12+
T
(°C)
layer spacing d (Å)
104
33.8
32.8
34.2
33.6
33.4
33.9
34.9
35.0
34.3
a
175
175
177
175
177
178
147
148
Scheme 7. Synthesis of Host LCP
(SbCl −)2/LCP
6
2
2
3
3
/LCP
2
+(SbCl −)2/LCP
6
/LCP
2
+(SbCl −)2/LCP
6
BDTBT/LCP
BDTBT (SbCl6−)2/LCP
2+
a
Each complex contained 0.1 μmol of molecular switch or
b
2+
corresponding SbCl salt per milligram of LCP. Except for 2 /
6
LCP, the layer spacings and temperatures reported were determined
during cooling.
a
Reagents and conditions: (a) methacryloyl chloride, Et N, THF, 0
3
°C; (b) AIBN, toluene, 95 °C.
2
+
2+
2+
consisting of molecular switch dopants (1, 1 , 2, 2 , 3, 3 ,
2
+
BDTBT, or BDTBT ) and host LCP were prepared and their
nanostructures were analyzed. All molecular switches and their
corresponding SbCl salts except BDTBT (SbCl ) (Figure
2
+
−
6
6
2
Figure 9. Layer spacings d for all complexes and pure LCP.
S6, Supporting Information) formed homogeneous complexes
2+
with LCP. The XRD patterns for 3/LCP and 3 /LCP are
shown as examples in Figure 8. Pure LCP and all the complexes
showed diffraction patterns that were characteristic of a smectic
A phase, indicating that the original smectic order structure of
LCP was maintained even after complexes with molecular
switches were formed (Figure S7, S8, S9, and S10, Supporting
Information). The layer spacings for all the complexes and pure
LCP are listed in Table 2 and shown in Figure 9. A distinctly
smaller layer spacing was observed for 1/LCP than for pure
LCP, but such remarkable decrease in the layer spacings were
not found for 2/LCP and 3/LCP compared with that for pure
LCP. On the other hand, BDTBT/LCP showed a larger layer
spacing than pure LCP.
This result can be explained as follows. The terphenyl units
of 1 in 1/LCP are directly attached to the bithienyl scaffold,
forming a rigid structure, and the conformation of the polymer
backbone of the host LCP may strongly depend on the
conformation of dopant 1 because of the attractive π−π
interactions between the terphenyl units, which cause the
shrunken nanostructure of the smectic layer structure. We
speculate that intermolecular interactions between biphenyl
units attached to the thiophene moieties and terphenyl pendant
group of the LCP in 2/LCP are not strong enough to change
72
the nanostructure of the host LCP. A structural resemblance
between the dopant and host molecules is a crucial factor for
69
homogeneous complexes being formed. Strong attractive π−π
interactions between the terphenyl units may exist in the
complex 3/LCP, similar to 1/LCP, but the LCP nanostructure
is probably less affected in 3/LCP than in 1/LCP because of
the flexible spacer connecting the terphenyl units and
73
thiophene rings. In the case of BDTBT, there is no structural
resemblance between BDTBT and terphenyl mesogenic units
of LCP, and this results in poor molecular interaction between
69
BDTBT and mesogenic moieties of LCP. Consequently,
BDTBTs may be intercalated not inside the layer of mesogenic
moieties but outside the layer of mesogenic moieties of LCP
leading to the expansion of interlayer distance.
Figure 8. X-ray diffraction patterns for (A) 3/LCP at 177 °C and (B)
2
+
2+
3
/LCP at 178 °C during cooling. The inset shows diffraction peaks
Larger layer spacings were found for complexes 1 /LCP and
2+
2+
for 3/LCP and 3 /LCP in small-angle region.
3 /LCP than for complexes 1/LCP and 3/LCP (indicated by
G
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lower diffraction angles, see Figure 8A inset), but the layer
complexes of the molecular switch and host LCP were
prepared, and the changes in smectic layer structures of these
complexes were examined using XRD. Layer spacings for the
2
+
spacings were smaller for the complexes 2 /LCP and
2+
BDTBT /LCP than for complexes 2/LCP and BDTBT/
2
+
2+
2+
2+
LCP. The layer spacings for 1 /LCP and 3 /LCP were higher
than those for 1/LCP and 3/LCP by 1.4 and 1.0 Å,
redox pairs 1/1 and 3/3 complexes with LCP were larger
when molecular switches were in the oxidized cationic form
than when they were in the neutral cyclized form. In this study,
we demonstrated the potential for molecular switches to be
used as functional dopants for tuning the nanostructures of host
polymeric materials. This should be a crucial factor in
constructing soft actuators consisting of deformable host
media (polymers or gels) and actuating dopants (molecular
switches). For future challenges to prepare redox-driven
actuators, the design of electrode that can achieve the effective
electron transfer between molecular switches and electrode
should be optimized. The molecular switches presented here
should provide a useful impetus for development of redox-
driven molecular actuators in practical applications.
2
+
−
2+
−
respectively. The ionic pairs 1 (SbCl ) and 3 (SbCl )
6
2
6
2
could expand the LCP smectic layer spacing parallel to the
normal layer. As depicted schematically in Figure 10, the
EXPERIMENTAL SECTION
General Procedures. Unless otherwise noted, all reactions were
■
run under nitrogen atmosphere. CH Cl and CH CN were distilled
2
2
3
1
13
from CaH before use. Most H and C were recorded at 25 °C on a
2
4
00 and 100 MHz spectrometer, respectively. Chemical shifts are in
parts per million (ppm) using either the solvent’s residual protons or
TMS employed as the internal standard. For mesomorphic
compounds, DSC measurements were carried out to determine
phase transition temperatures. Heating and cooling rates were 10 °C/
min. The transition temperatures were determined by the minimum of
exothermic and maximum point of endothermic peaks, respectively. A
polarizing microscope equipped with hot stage and crossed polarizers
were used for visual observation of mesophases. The following
abbreviations are used to describe the phase transition behaviors. Cr:
crystal; N: nematic; S : smectic A; S : smectic E; S : ordered smectic;
Figure 10. Schematic illustration of change in layer spacings of LCP
complexes based on the redox-induced interconversion of guest
molecular switches. (A) Complexes of LCP with cyclized molecular
switch and (B) complexes of LCP with oxidized cationic salt of
molecular switch.
A
E
X
formation of molecular switch ionic pairs requires a large free
volume of LCP because of the intercalation of counteranions
and changes in the molecular shape compared with that of the
I: isotropic liquid. Polymer molecular weights and polydispersity
indexes (PDI) were determineed by gel permeation chromatography
(
GPC). Polystyrene standards were used for calibration, and THF was
7
4
cyclized form. This could cause the LCP layer spacing to
increase, but the influence of the counteranions may not be
dominant because of the small differences in the nanostructures
used as an eluent at a flow rate of 1.0 mL/min. XRD scans of polymers
or molecular switch were performed to determine the type of liquid-
crystalline phases and layer spacing of polymers. Cyclic voltammetry
was carried out in a three-compartment cell. All solutions were purged
with nitrogen and retained under inert atmosphere during experi-
ments.
2
+
2+
2+
of 2/LCP and 2 /LCP. In contrast to 1/1 and 3/3 ,
2+
BDTBT /LCP showed smaller layer spacings than those of
BDTBT/LCP. Such decrease in layer spacings suggests that the
2
+
2,3-Difluoro-4-(4-butoxyphenyl)benzene (5). A suspension of
oxidization of BDTBT to BDTBT causes a reduction in
7
5
Pd(PPh
) (1.06 g, 0.92 mmol) and 4 (7.00 g, 30.6 mmol) in DME
3 4
orientational order of smectic structures of LCP. To
investigate the effects of temperatures on the stability of the
smectic layer structures of the complexes, the layer spacings of
(60 mL) was stirred at room temperature for 10 min. To this
suspension were added subsequently a solution of 2,3-difluorophe-
nylboronic acid (4.96 g, 31.4 mmol) in ethanol (15 mL) and aqueous
Na CO (2 M solution, 30 mL, 60 mmol). The mixture was heated to
2+
3
/LCP and 3 /LCP were measured with different temper-
2
3
atures (Table S1 and S2, Supporting Information). As reported
reflux for 22 h, cooled to room temperature, and extracted with
CH Cl three times. The combined extracts were washed with water
and brine, dried over Na SO , and filtered. The solvent was evaporated
76
by Lemieux et al., both complexes did not show drastic
changes of the layer spacings in smectic A phases. This suggests
that the complexes formed stable orientational order structures
in smectic A phase and tilting of mesogenic units like smectic C
2
2
2
4
and the residue was purified by column chromatography (silica gel,
eluent: hexane followed by hexane/CH Cl = 10/1) to afford 5 (7.13
2
2
1
7
6
g, 27.2 mmol): yield 89%; white solid; mp 33−34 °C; H NMR (400
phase did not occur.
MHz, CDCl ) δ = 0.99 (t, J = 7.4 Hz 3H), 1.47−1.56 (m, 2H), 1.76−
3
These results suggest that the ordered structures of polymer
matrices can be changed by the redox-triggered interconversion
between a molecular switch and its corresponding oxidized
dication.
1
7
.83 (m, 2H), 4.01 (t, J = 6.5 Hz, 2H), 6.96−7.00 (AA’BB’, 2H),
13
.06−7.18 (m, 3H), 7.45−7.48 (AA’BB’, 2H); C NMR (100 MHz,
CDCl ) δ = 13.9 (s), 19.4 (s), 31.4 (s), 67.8 (s), 114.7 (s), 115.4 (d, J
3
= 17 Hz), 124.0 (dd, J = 8.1 Hz, J = 4.9 Hz), 125.1 (dd, J = 3.3 Hz, J =
2
.3 Hz), 126.9 (dd, J = 2.9 Hz, J = 1.0 Hz), 130.2 (d, J = 3.9 Hz), 131.2
CONCLUSIONS
(d, J = 10 Hz), 148.0 (dd, J = 13 Hz, J = 247 Hz), 151.3 (dd, J = 14
■
+
Hz, J = 247 Hz), 159.4 (s); HR-MS (APCI) C H F O [M] calcd
16
16 2
Redox-driven molecular switches consisting of a benzodithio-
lylbithienyl scaffold and rigid biphenyl or terphenyl units were
designed and synthesized for use as functional dopants to
induce changes in the nanostructures of host polymers. UV and
CV studies confirmed that the interconversion between the
cationic form and neutral cyclized form occurred. Binary
m/z 262.1169, found m/z 262.1165.
,3-Difluoro-4-(4-butoxyphenyl)phenylboronic acid (6). A
solution of 5 (2.57 g, 9.78 mmol) in THF (20 mL) was stirred at −78
C. BuLi (1.66 M in hexane, 8 mL, 13.3 mmol) was added dropwise to
2
°
the solution. The reaction mixture was stirred at the same condition
for 3 h, then trimethyl borate (3.36 g, 32.3 mmol) was added to the
H
dx.doi.org/10.1021/jo501072u | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
mixture. The mixture was allowed to warm to room temperature
overnight and quenched with 4 M HCl solution (30 mL). The organic
CDCl ) δ = 1.00 (t, J = 7.2 Hz 3H), 1.47−1.57 (m, 2H), 1.77−1.84
3
(m, 2H), 4.02 (t, J = 6.5 Hz, 2H), 4.83 (brs, 1H), 6.92−6.95 (AA’BB’,
2H), 6.98−7.01 (AA’BB’, 2H), 7.17−7.23 (m, 2H), 7.47−7.53(m,
layer was separated, and the aqueous layer was extracted with Et O
2
three times. The combined organic extracts were washed with water
4H); 13C NMR (100 MHz, DMSO-d ) δ = 13.7 (s), 18.7 (s), 30.7 (s),
6
and brine, dried over Na SO , and filtered. The solvent was
67.3 (s), 114.7 (s), 115.6 (s), 124.4 (s), 124.6 (s), 124.68 (d, J = 4
Hz), 124.73 (s), 126.0 (s), 127.9 (d, J = 4 Hz), 128.6 (s), 129.9 (dd, J
= 1.6 Hz, J = 1.7 Hz), 147.5 (dd, J = 7 Hz, J = 248 Hz), 147.7 (dd, J =
2
4
evaporated, and the residue was purified by column chromatography
silica gel, eluent: hexane/ethyl acetate = 3/2) to give 6 (2.44 g, 7.97
(
1
−1
mmol): yield 82%; white solid; mp 129−130 °C; H NMR (400 MHz,
7 Hz, J = 248 Hz), 157.7 (s), 158.8 (s); IR (KBr, cm ) 3429 (ν OH);
+
CDCl ) δ = 0.99 (t, J = 7.4 Hz 3H), 1.47−1.56 (m, 2H), 1.76−1.83
HR-MS (APCI) C H F O [M − H] calcd m/z 353.1353, found m/
3
22 19
2
2
(
(
m, 2H), 4.02 (t, J = 6.5 Hz, 2H), 5.09 (d, J = 5.6 Hz, 2H), 6.97−7.01
AA’BB’, 2H), 7.22−7.26 (m, 1H), 7.48−7.53 (AA’BB’, 2H), 7.56−
z 353.1349.
1-(8-Hydroxyoctyl-1-oxy)-4-[2,3-difluoro-4-(4-butoxy-
phenyl)phenyl]benzene (10). A mixture of 9 (1.11 g, 3.13 mmol),
KI (0.13 g, 0.77 mmol), K CO (0.88 g, 6.36 mmol), and 8-bromo-1-
2 3
octanol (1.22 g, 5.84 mmol) in DMF (20 mL) was heated and stirred
at 85 °C for 20 h. The resulting mixture was poured into water (100
mL), and then the precipitate was collected by filtration and washed
with ethanol several times. The crude product was purified by column
7
3
1
2
1
3
.60 (m, 1H); 13C NMR (100 MHz, DMSO-d ) δ = 13.7 (s), 18.8 (s),
6
0.8 (s), 67.3 (s), 114.7 (s), 124.5 (s), 126.1 (d, J = 2.1 Hz), 129.7 (s),
29.99 (s), 130.02 (s), 131.2 (d, J = 10 Hz), 147.0 (dd, J = 15 Hz, J =
46 Hz), 153.5 (dd, J = 12 Hz, J = 243 Hz), 158.9 (s); IR (KBr, cm )
358 (ν BO); HR-MS (ES) C H BF O [M + H] calcd m/z
07.1317, found m/z 307.1309.
-Bromo-4-[2,3-difluoro-4-(4-butoxyphenyl)phenyl]-
−1
+
16
18
2
3
1
chromatography (silica gel, eluent: CH Cl followed by CH Cl /
2 2 2 2
benzene (7). The experimental procedure was as described for the
preparation of 5 except that benzene was used as a solvent, and the
reaction time was 1.5 h. Quantities: 1-iodo-4-bromobenzene (1.45 g,
methanol = 20/1) to give 10 (1.39 g, 2.89 mmol): yield 92%; white
solid; phase transition temperature/°C (DSC on second heating) Cr
1
117 N 162 I; H NMR (400 MHz, CDCl ) δ = 1.00 (t, J = 7.4 Hz,
3
5
.11 mmol), 6 (1.72 g, 5.61 mmol), Pd(PPh ) (0.18 g, 0.15 mmol),
3H), 1.33−1.62 (m, 12H), 1.77−1.85 (m, 4H), 3.65 (t, J = 6.6 Hz,
3
4
aqueous Na CO (2 M solution, 5.0 mL, 10.0 mmol). The crude
product was purified by column chromatography (silica gel, eluent:
hexane/CH Cl = 7/1) to afford 7 (1.25 g, 3.00 mmol): yield 59%;
2H), 4.01 (t, J = 6.2 Hz, 2H), 4.02 (t, J = 6.2 Hz, 2H), 6.97−7.01
2
3
1
3
(AA’BB’, 4H), 7.20−7.21 (m, 2H), 7.50−7.53 (AA’BB’, 4H);
C
NMR (100 MHz, CDCl ) δ = 14.0 (s), 19.4 (s), 25.8 (s), 26.1 (s),
2
2
3
white solid; phase transition temperature/°C (DSC on second
29.4 (s), 29.5 (s), 31.5 (s), 32.9 (s), 63.2 (s), 67.9 (s), 68.2 (s), 114.8
(s), 124.4 (s), 124.5 (s), 124.5 (s), 127.01 (s), 127.04 (s), 128.98 (s),
129.01 (s), 129.1 (s), 130.1 (s), 148.6 (dd, J = 15 Hz, J = 249 Hz),
1
heating) Cr 116 SX 122 SA 145 N 182 I; H NMR (400 MHz,
CDCl ) δ = 1.00 (t, J = 7.4 Hz 3H), 1.47−1.57 (m, 2H), 1.77−1.84
3
−1
(
(
7
m, 2H), 4.02 (t, J = 6.5 Hz, 2H), 6.98−7.01 (AA’BB’, 2H), 7.18−7.24
m, 2H), 7.44−7.47 (AA’BB’, 2H), 7.49−7.53 (AA’BB’, 2H), 7.58−
159.26 (s), 159.30 (s); IR (KBr, cm ) 3323 (ν OH), 1053 (ν CO);
+
HR-MS (ES) C30H F O Na [M + Na] calcd m/z 505.2530, found
36 2 3
.62 (AA’BB’, 2H); 13C NMR (100 MHz, CDCl ) δ = 14.00 (s), 19.4
m/z 505.2541.
3
(
s), 31.5 (s), 68.0 (s), 114.9 (s),122.6 (s), 124.57 (dd, J = 28 Hz, J =
1-(8-p-Toluenesulfonyloxyoctyloxy)-4-[2,3-difluoro-4-(4-
2
1
1
2
4
.4 Hz), 124.61 (dd, J = 28 Hz, J = 3.7 Hz), 126.7 (d, J = 1.7 Hz),
28.0 (d, J = 4.5 Hz), 128.1 (d, J = 4.5 Hz), 130.2 (d, J = 2.3 Hz),
30.6 (d, J = 2.1 Hz), 132.0 (s), 133.8 (s), 148.6 (dd, J = 16 Hz, J =
butoxyphenyl)phenyl]benzene (11). To a solution of 10 (1.32 g,
2.74 mmol) in CH Cl (60 mL) were added p-toluenesulfonyl chloride
2 2
(0.79 g, 4.16 mmol), 4-dimethylaminopyridine (36 mg, 0.30 mmol),
and triethylamine (0.42 g, 4.16 mmol), and the solution was stirred at
room temperature for 18 h. Then the reaction mixture was quenched
+
50 Hz), 159.5 (s); HR-MS (ES) C H BrF O [M] calcd m/z
22
19
2
16.0587, found m/z 416.0579.
1
-(4-Butoxyphenyl)-4-[4-(pinacolboronato)phenyl]-2,3-di-
with sat. NH
times. The combined organic extracts were dried over Na
The solvent was evaporated, and the residue was purified by column
chromatography (silica gel, eluent: CHCl /hexane = 3/1 followed by
CHCl ) to afford 11 (1.62 g, 2.55 mmol): yield 93%; white waxy solid;
phase transition temperature/°C (DSC on second heating) Cr 72 S
4
Cl aqueous solution and extracted with CHCl
3
three
fluorobenzene (8). A mixture of 7 (833 mg, 2.00 mmol),
bis(pinacolato)diboron (609 mg, 2.40 mmol), KOAc (590 mg, 6.01
mmol), and PdCl (dppf) (49 mg, 0.06 mmol) in DMF (12 mL) was
stirred at 80 °C for 4 h. After cooling the reaction mixture to room
temperature, the mixture was diluted with CH Cl and water. The
organic layer was separated, and the aqueous layer was extracted with
CH Cl three times. The combined organic extracts were washed with
water and brine, dried over Na SO , and filtered. The solvent was
2
SO , filtered.
4
2
3
3
2
2
A
1
95 N 101 I; H NMR (400 MHz, CDCl ) δ = 1.00 (t, J = 7.6 Hz, 3H),
3
1.26−1.36 (m, 6H), 1.41−1.57 (m, 4H), 1.62−1.69 (m, 2H), 1.75−
1.84 (m, 4H), 2.45 (s, 3H), 3.98−4.05 (m, 6H), 6.97−7.00 (m, 4H),
7.20−7.21 (m, 2H), 7.34 (d, J = 8.0 Hz, 2H), 7.51 (d, J = 8.6 Hz, 4H),
2
2
2
4
removed under reduced pressure. Purification by column chromatog-
raphy (silica gel, eluent: hexane/CH Cl = 1/1) afforded 8 (682 mg,
1
7.80 (d, J = 8.0 Hz, 2H); 13C NMR (100 MHz, CDCl
) δ = 14.0 (s),
2
2
3
1
.47 mmol): yield 74%; white solid; mp 143−144 °C; H NMR (400
19.4 (s), 21.8 (s), 25.4 (s), 26.1 (s), 28.95 (s), 28.98 (s), 29.25 (s),
29.32 (s), 31.5 (s), 67.9 (s), 68.1 (s), 70.8 (s), 114.77 (s), 114.78 (s),
124.30 (s), 124.32 (s), 126.9 (s), 127.0 (d, J = 1 Hz), 127.1 (d, J = 1
Hz), 128.0 (s), 129.1 (s), 120.0 (s), 130.10 (s), 130.12 (s), 130.14 (s),
133.4 (s), 144.8 (s), 148.6 (dd, J = 16 Hz, 250 Hz), 159.2 (s), 159.3
MHz, CDCl ) δ = 1.00 (t, J = 7.3 Hz, 3H), 1.37 (s, 12H), 1.47−1.57
3
(
(
7
m, 2H), 1.77−1.84 (m, 2H), 4.02 (t, J = 6.6 Hz, 2H), 6.98−7.02
AA’BB’, 2H), 7.21−7.27 (m, 2H), 7.51−7.53 (AA’BB’, 2H), 7.59−
13
.61 (AA’BB’, 2H), 7.90−7.93 (AA’BB’, 2H); C NMR (100 MHz,
−
1
CDCl ) δ = 14.0 (s), 19.4 (s), 25.0 (s), 31.4 (s), 67.9 (s), 84.1 (s),
(s); IR (KBr, cm ) 1358 (νas SO
2
), 1178 (ν
C H F O S [M − H] calcd m/z 635.2643, found m/z 635.2651.
37 41 2 5
s 2
SO ); HR-MS (APCI)
3
+
1
14.8 (s), 124.6 (dd, J = 3 Hz, 4 Hz), 124.8 (dd, J = 3.9 Hz, J = 4.3
Hz), 126.9 (dd, J = 1 Hz, J = 2 Hz), 128.3 (d, J = 3 Hz), 129.2 (d, J =
0 Hz), 130.0 (d, J = 10 Hz), 130.2 (d, J = 3 Hz), 135.2 (s), 137.6 (d, J
1 Hz), 137.6 (d, J = 1 Hz), 148.6 (dd, J = 14 Hz, J = 247 Hz), 148.7
4,4′-Dibromo-2,2′-bis(1,3-dioxolan-2-yl)-3,3′-bithienyl (13).
1
=
To a solution of 12 (1.33 g, 3.50 mmol) in benzene (50 mL) were
added ethylene glycol (1.21 g, 19.4 mmol) and p-toluenesulfonic acid
monohydrate (0.22 g, 1.17 mmol). The mixture was heated to reflux
using a Dean−Stark apparatus to remove water for 3 h and cooled to
−1
(
dd, J = 12 Hz, J = 246 Hz), 159.4 (s); IR (KBr, cm ) 1358 (ν BO);
+
HR-MS (EI) C H BF O [M] calcd m/z 464.2334, found m/z
4
28
31
2
3
64.2324.
room temperature. The mixture was diluted with CH
Cl , washed with
2 2
1
-Hydroxy-4-[2,3-difluoro-4-(4-butoxyphenyl)phenyl]-
sat. NaHCO aqueous solution, dried over Na SO , and filtered. The
3
2
4
benzene (9). The experimental procedure was as described for the
preparation of 5 except that the reaction time was 21.5 h. Quantities: 6
solvent was evaporated, and the residue was purified by column
chromatography (silica gel, eluent: CH Cl ) to afford 13 (1.56 g, 3.32
2
2
1
(
4.73 g, 15.5 mmol), 4-bromophenol (2.42 g, 14.0 mmol), Pd(PPh3)4
mmol): yield 95%; light yellow solid; mp 149−150 °C; H NMR (400
(
0.48 g, 0.42 mmol), DME (90 mL). The crude product was purified
MHz, CDCl ) δ = 3.89−3.97 (m, 4H), 4.04−4.12 (m, 4H), 5.80 (s,
3
13
by column chromatography (silica gel, eluent: hexane/ethyl acetate =
5/1 followed by 5/1) to give 9 (2.58 g, 7.28 mmol): yield 52%; white
2H), 7.39 (s, 2H); C NMR (100 MHz, CDCl ) δ = 65.46 (s), 65.49
3
−1
1
(s), 99.1 (s), 112.9 (s), 123.2 (s), 133.3 (s), 141.5 (s); IR (KBr, cm )
1076 (ν CO); HR-MS (ES) C H Br O S [M + H] calcd m/z
+
powder; phase transition temperature/°C (DSC on first cooling) I 175
S 173 Cr; (DSC on second heating) Cr 191 I; H NMR (400 MHz,
14
13
2
4 2
1
466.8622, found m/z 466.8601.
X
I
dx.doi.org/10.1021/jo501072u | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
2
,2′-Bis(1,3-dioxolan-2-yl)-4,4′-diformyl-3,3′-bithienyl (14).
(dd, J = 13 Hz, J = 250 Hz), 148.4 (dd, J = 15 Hz, J = 249 Hz), 159.6
−1
A solution of 13 (988 mg, 2.11 mmol) in THF (6 mL) was added
dropwise to a mixture of BuLi (1.65 M in hexane, 3.1 mL, 5.12 mmol)
and THF (6 mL) at −78 °C. Then the mixture was stirred for 1 h. To
the mixture was added DMF (1.3 mL, 16.8 mmol), and the reaction
mixture was further stirred for 1 h. The reaction mixture was allowed
to warm to room temperature and treated with sat. NH Cl aqueous
solution. The organic layer was separated, and the aqueous layer was
extracted with CH Cl three times. The combined organic extracts
(s), 182.9 (s); IR (KBr, cm ) 1666 (ν CO); HR-MS (EI)
+
C H O F S [M] calcd m/z 742.1835, found m/z 742.1829.
42
34
4 4 2
2,2′-Diformyl-4,4′-bis(8-{4-[2,3-difluoro-4-(4-butoxyphenyl)-
phenyl]phenyloxy}octyl-1-oxymethoxy)-3,3′-bithienyl (18). To
a solution of 15 (272 mg, 0.74 mmol) in DMF (5 mL) was added
NaH (98 mg, 60 wt % in mineral oil, 2.45 mmol), and the mixture was
stirred at room temperature for 1.5 h. Next, a solution of 11 (1.046 g,
1.64 mmol) in DMF (5 mL) was added to the mixture, and then the
mixture was heated to 75 °C and stirred for 21 h. After cooling to the
room temperature, the reaction mixture was quenched with sat.
4
2
2
were dried over Na SO , filtered and concentrated. The residue was
purified by column chromatography (silica gel, eluent: CH Cl /ethyl
acetate = 5/1) to afford 14 (367 mg, 1.00 mmol): yield 47%; light
2
4
2
2
NaHCO
aqueous solution and extracted with CH
Cl
2
three times.
3
2
1
yellow powder; mp 140−143 °C; H NMR (400 MHz, CDCl ) δ =
The combined organic extracts were dried over Na
2
SO
4
, filtered and
3
3
9
(
.85−3.94 (m, 4H), 4.00−4.12 (m, 4H), 5.78 (s, 2H), 8.23 (s, 2H),
concentrated. The residue was dissolved in THF and treated with 6 M
HCl (20 mL). The mixture was stirred at room temperature for 2 h
.57 (s, 2H); 13C NMR (100 MHz, CDCl ) δ = 65.5 (s), 65.7 (s), 98.4
3
s), 131.6 (s), 135.3 (s), 141.2 (s), 142.3 (s), 184.8 (s); IR (KBr,
and extracted with CH
were washed with water and brine, dried over Na
concentrated. The crude product was purified by column chromatog-
raphy (silica gel, eluent: CHCl ) to give 18 (621 mg, 0.51 mmol):
2
Cl
2
three times. The combined organic extracts
−
1
+
cm ) 1687 (ν CO); HR-MS (EI) C H O S [M] calcd m/z
2
SO , filtered and
4
16
14
6 2
3
66.0232, found m/z 366.0226.
2
,2′-Bis(1,3-dioxolan-2-yl)-4,4′-bishydroxymethyl-3,3′-bi-
3
thienyl (15). To a solution of 14 (118 mg, 0.32 mmol) in ethanol (5
yield 69%; white waxy solid; phase transition temperature/°C (DSC
1
mL) was added NaBH (51 mg, 1.35 mmol) at room temperature.
on second heating) Cr 94 SA 136 N 142 I; H NMR (400 MHz,
4
The reaction mixture was stirred for 2.5 h and concentrated. The
CDCl ) δ = 0.99 (t, J = 7.4 Hz, 6H), 1.23−1.39 (m, 12H), 1.42−1.56
3
residue was diluted with CH Cl and water. The organic layer was
(m, 12H), 1.76−1.83 (m, 8H), 3.29 (t, J = 6.6 Hz, 4H), 3.98−4.02 (m,
2
2
2
2
separated, and the aqueous layer was extracted with CH Cl three
8H), 4.14 (d, J = 12 Hz, 2H), 4.20 (d, J = 12 Hz, 2H), 6.97−6.99
(AA’BB’, 8H), 7.18−7.19 (m, 4H), 7.50 (d, J = 8.6 Hz, 8H), 7.78 (d, J
2
2
times. The combined organic extracts were dried over Na SO , filtered,
2
4
and concentrated to afford pure 15 (112 mg, 0.30 mmol): yield 94%;
= 0.8 Hz, 2H), 9.53 (d, J = 0.8 Hz, 2H); 13C NMR (100 MHz, CDCl )
3
1
light yellow powder; mp 121−123 °C; H NMR (400 MHz, CDCl ) δ
δ = 14.0 (s), 19.4 (s), 26.11 (s), 26.13 (s), 29.36 (s), 29.40 (s), 29.45
(s), 29.51 (s), 31.4 (s), 66.6 (s), 67.9 (s), 68.1 (s), 71.4 (s), 114.7 (s),
124.40 (d, J = 2 Hz), 124.44 (d, J = 2 Hz), 124.5 (d, J = 2 Hz), 126.96
(d, J = 1 Hz), 127.02 (d, J = 1 Hz), 128.9 (s), 129 (s), 128.99 (s),
129.03 (s), 130.1 (s), 132.6 (s), 140.8 (s), 141.5 (s), 142.3 (s), 148.6
(dd, J = 249 Hz, J = 16 Hz), 159.2 (s), 159.3 (s), 182.9 (s); IR (KBr,
3
=
2.95 (dd, J = 4.2 Hz, J = 8.1 Hz, 2H), 3.86−3.92 (m, 4H), 3.97−4.07
13
(
m, 4H), 4.18−4.33 (m, 4H), 5.72 (s, 2H), 7.43 (s, 2H); C NMR
(
1
100 MHz, CDCl ) δ = 58.6 (s), 65.2 (s), 65.9 (s), 99.2 (s), 125.1 (s),
3
+
33.6 (s), 139.5 (s), 142.8 (s); HR-MS (EI) C H O S [M] calcd
16
18
6 2
m/z 370.0545, found m/z 370.0537.
−
1
+
2
,2′-Diformyl-4,4′-bis{4-[2,3-difluoro-4-(4-butoxyphenyl)-
cm ) 1672 (ν CO); HR-MS (APCI) C H O F S [M + H]
72
79
8 4 2
phenyl]phenyl}-3,3′-bithienyl (16). A flask charged with 12 (73
calcd m/z 1211.5147, found m/z 1211.5140.
mg, 0.19 mmol), 8 (195 mg, 0.42 mmol), PdCl (dppf) (11 mg, 0.013
2,2′-Bis(1,3-benzodithiol-2-yl)-4,4′-bis{4-[2,3-difluoro-4-(4-
butoxyphenyl)phenyl]phenyl}-3,3′-bithienyl (19). A solution of
16 (66 mg, 74 μmol), 1,2-benzenedithiol (37 mg, 260 μmol), and p-
toluenesulfonic acid monohydrate (24 mg, 126 μmol) in benzene (12
mL) was heated to reflux for 4.5 h. To the solution was added sat.
2
mmol) was flashed with N . DMF (6 mL) was added to the mixture,
2
and the mixture was stirred at room temperature. Then aqueous
Na CO (2 M, 1 mL, 2.00 mmol) was added to the mixture. The
2
3
suspension was stirred at 80 °C for 26 h. After cooling to room
temperature, the resulting suspension was filtered over Celite pad and
diluted with CH Cl , washed with water and brine, dried over Na SO ,
NaHCO aqueous solution, and then the mixture was extracted with
3
CH Cl three times. The combined extracts were dried over Na SO ,
2
2
2
4
2
2
2
4
filtered and concentrated. Purification on column chromatography
silica gel, eluent: CHCl ) gave 16 (95 mg, 0.11 mmol): yield 58%;
filtered, and concentrated. The residue was purified by column
(
chromatography (alumina, eluent: hexane/CH Cl = 4/1 followed by
3
2
2
1
light yellow solid; mp 211−214 °C; H NMR (400 MHz, CDCl ) δ =
1/1) and recrystallized from toluene/hexane to give 19 (75 mg, 66
3
1
1
.00 (t, J = 7.4 Hz, 6H), 1.47−1.57 (m, 4H), 1.77−1.84 (m, 4H), 4.02
μmol): yield 89%; colorless solid; mp 202−204 °C; H NMR (400
(
t, J = 6.5 Hz, 4H), 6.83 (d, J = 8.1 Hz, 4H), 7.00 (d, J = 8.7 Hz, 4H),
MHz, CDCl ) δ = 1.00 (t, J = 7.4 Hz, 6H), 1.48−1.57 (m, 4H), 1.77−
3
7
7
1
.16−7.26 (m, 4H), 7.34 (d, J = 7.9 Hz, 4H), 7.52 (d, J = 8.3 Hz, 4H),
1.84 (m, 4H), 4.03 (t, J = 6.5 Hz, 4H), 5.99 (s, 2H), 6.98−7.02
(AA’BB’, 4H), 7.05−7.10 (m, 8H), 7.13−7.15 (m, 2H), 7.22−7.27 (m,
6H), 7.36 (s, 2H), 7.42−7.44 (AA’BB’, 4H), 7.50−7.54 (AA’BB’ 4H);
.77 (s, 2H), 9.83 (s, 2H) ; 13C NMR (100 MHz, CDCl ) δ = 14.0 (s),
3
9.4 (s), 31.4 (s), 67.9 (s), 114.8 (s), 124.5 (dd, J = 3.3 Hz, J = 3.8
13
Hz), 124.7 (dd, J = 3.5 Hz, J = 4.0 Hz), 126.7 (s), 128.2 (s), 129.0 (s),
29.1 (s), 130.1 (s), 130.2 (s), 132.2 (s), 133.7 (s), 134.3 (s), 139.9
s), 143.0 (s), 144.6 (s), 148.5 (dd, J = 13 Hz, J = 250 Hz), 148.7 (dd,
C NMR (100 MHz, CDCl ) δ = 14.0 (s), 19.4 (s), 31.5 (s), 50.6 (s),
3
1
67.9 (s), 114.8 (s), 122.3 (s), 122.4 (s), 123.4 (s), 124.58 (d, J = 3
Hz), 124.64 (d, J = 3 Hz), 126.2 (d, J = 1 Hz), 126.9 (dd, J = 1.2 Hz, J
= 2.0 Hz), 128.2 (s), 128.9 (d, J = 11 Hz), 129.1 (d, J = 3 Hz), 129.8
(d, J = 10 Hz), 130.1 (s), 130.2 (s), 131.1 (s), 133.9 (s), 135.2 (s),
136.8 (s), 137.2 (s), 141.4 (s), 144.5 (s), 148.7 (dd, J = 19 Hz, J = 255
(
−1
J = 15 Hz, J = 250 Hz), 159.4 (s), 183.1 (s); IR (KBr, cm ) 1668 (ν
+
CO); HR-MS (APCI) C H O F S [M ] calcd m/z 894.2461,
54
42
4 4 2
found m/z 894.2465.
+
2
,2′-Diformyl-4,4′-bis[2,3-difluoro-4-(4-butoxyphenyl)-
Hz), 159.4 (s); HR-MS (APCI) C H O F S [M + H ] calcd m/z
66
51
2 4 6
phenyl]-3,3′-bithienyl (17). The experimental procedure was as
1
143.2144, found m/z 1143.2140.
described for the preparation of compound 5. Quantities: 12 (0.99 g,
2
,2′-Bis(1,3-benzodithiol-2-yl)-4,4′-bis[2,3-difluoro-4-(4-
2
.60 mmol), 6 (2.09 g, 6.83 mmol), Pd(PPh ) (0.18 g, 0.16 mmol),
butoxyphenyl)]phenyl-3,3′-bithienyl (20). The experimental
procedure was as described for the preparation of compound 19.
Quantities: 17 (848 mg, 1.14 mmol), 1,2-benzenedithiol (485 mg, 3.41
mmol), p-toluenesulufonic acid monohydrate (128 mg, 0.67 mmol).
The crude product was purified by column chromatography (alumina,
eluent: toluene/hexane = 1/1 followed by 2/1) to give 20 (989 mg,
3
4
aqueous Na CO (2 M, 5.8 mL, 11.6 mmol). The crude product was
2
3
purified by column chromatography (silica gel, eluent: hexane/ethyl
acetate = 5/1) to give 17 (1.17 g, 1.57 mmol): yield 61%; yellow solid;
1
mp 160−163 °C; H NMR (400 MHz, CDCl ) δ = 0.99 (t, J = 7.4 Hz,
3
6
6
4
H), 1.46−1.55 (m, 4H), 1.76−1.83 (m, 4H), 4.01 (t, J = 6.5 Hz, 4H),
.39 (t, J = 6.9 Hz, 2H), 6.92 (t, J = 6.9 Hz, 2H), 6.95−6.99 (AA’BB’,
H), 7.41−7.44 (AA’BB’, 4H), 7.79 (s, 2H), 9.83 (d, J = 1.4 Hz, 2H);
1
1.00 mmol): yield 88%; colorless solid; mp 193−195 °C; H NMR
(400 MHz, CDCl ) δ = 0.99 (t, J = 7.4 Hz, 6H), 1.47−1.56 (m, 4H),
3
1
3
C NMR (100 MHz, CDCl ) δ = 14.0 (s), 19.3 (s), 31.4 (s), 67.9 (s),
1.76−1.83 (m, 2H), 4.01 (t, J = 6.5 Hz, 4H), 6.20 (s, 2H), 6.45−6.49
(m, 2H), 6.91−6.95 (m, 2H), 6.95−7.00 (AA’BB’, 4H), 7.07−7.14 (m,
3
114.8 (s), 121.5 (d, J = 12 Hz), 124.35 (s), 124.38 (s), 124.41 (s),
126.20 (s), 126.22 (s), 130.06 (s), 130.09 (s), 131.0 (s), 131.1 (s),
134.4 (d, J = 3 Hz), 136.6 (d, J = 2 Hz), 139.8 (s), 143.1 (s), 148.0
1
3
4H), 7.16−7.20 (m, 4H), 7.33 (s, 2H), 7.44−7.46 (AA’BB’, 4H);
C
NMR (100 MHz, CDCl ) δ = 14.0 (s), 19.4 (s), 31.4 (s), 50.9 (s),
3
J
dx.doi.org/10.1021/jo501072u | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
2
+
−
6
(
1
(
7.9 (s), 114.7 (s), 122.4 (s), 122.6 (s), 122.9 (d, J = 11 Hz), 124.1
s), 124.5 (s), 126.0 (d, J = 4 Hz), 126.4 (d, J = 3 Hz), 126.8 (s),
30.06 (s), 130.13 (d, J = 3 Hz), 131.4 (s), 133.4 (d, J = 2 Hz), 136.8
s), 137.0 (s), 144.1 (s), 148.2 (dd, J = 14 Hz, J = 248 Hz), 148.6 (dd,
J = 14 Hz, J = 249 Hz), 159.4 (s); HR-MS (APCI) C H O F S [M
Compound 1. To a solution of 1 (SbCl ) (116 mg, 64 μmol) in
6 2
the mixture of MeCN (4 mL)/THF (4 mL) was added Zn powder
(115 mg, 1.76 mmol). Then the mixture was stirred at room
temperature for 3 h, and filtered to remove Zn powder. The filtrate
was concentrated, and the residue was purified by column
chromatography (alumina, eluent: CH
by CH Cl ) to give 1 (61 mg, 67.2 μmol): yield 83%; colorless solid;
54
43
2 4 6
+
+
H] calcd m/z 991.1518, found m/z 991.1506.
2 2
Cl /hexane = 1/2 followed
2,2′-Bis(1,3-benzodithiolyl)-4,4′-bis (8-{4-[2,3-difluoro-4-(4-
2
2
1
butoxyphenyl)phenyl]phenyloxy}octyl-1-oxymethoxy)-3,3′-bi-
thienyl (21). The experimental procedure was as described for the
preparation of compound 19. Quantities: 18 (464 mg, 0.38 mmol),
mp 250−254 °C; H NMR (500 MHz, CDCl ) δ = 0.99 (t, J = 7.4 Hz,
3
6H), 1.48−1.55 (m, 4H), 1.77−1.82 (m, 4H), 4.01 (t, J = 6.5 Hz, 4H),
6.89−6.92 (AA’BB’, 4H), 6.96−7.00 (AA’BB’, 4H), 7.01−7.07 (m,
1
3
1,2-benzenedithiol (121 mg, 0.85 mmol), p-toluenesulfonic acid
10H), 7.15−7.17 (m, 6H), 7.19 (s, 2H), 7.48−7.51 (AA’BB’, 4H); C
monohydrate (17 mg, 0.09 mmol). Purification by column
chromatography (alumina, eluent: CH Cl /hexane = 1/1) gave 21
NMR (125 MHz, CDCl ) δ = 14.0 (s), 19.4 (s), 31.5 (s), 67.9 (s),
3
80.2 (s), 114.8 (s), 121.3 (d, J = 5 Hz), 124.49 (s), 124.51 (s), 125.5
(s), 125.8 (s), 126.1 (s), 126.9 (s), 128.1 (s), 128.6 (s), 129.0 (d, J = 9
Hz), 129.6 (d, J = 9 Hz), 130.1 (d, J = 2 Hz), 130.7 (s), 133.1 (s),
136.6 (d, J = 5 Hz), 138.2 (s), 141.3 (s), 144.5 (s), 148.5 (dd, J = 248
2
2
(
360 mg, 0.25 mmol): yield 66%; white powder; phase transition
temperature/°C (DSC on first cooling) I 122 N 116 S 104 S 79 Cr;
A
X
1
(
DSC on second heating) Cr 92 Cr 93 S 116 N 124 I; H NMR (400
A
MHz, CDCl ) δ = 0.99 (t, J = 7.4 Hz, 6H), 1.26−1.56 (m, 24H),
1
4
Hz, J = 15 Hz), 148.6 (dd, J = 250 Hz, J = 15 Hz), 159.4 (s); HR-MS
3
+
.76−1.83 (m, 8H), 3.29−3.39 (m, 4H), 3.97−4.03 (m, 8H), 4.08 (s,
H), 6.01 (s, 2H), 6.96−7.00(m, 8H), 7.05−7.07 (m, 4H), 7.18−7.24
(APCI) C66
1141.1982.
H
49
O
2
F
4
S
6
[M + H] calcd m/z 1141.1987, found m/z
2
+
−
13
Dication Salt 2 (SbCl ) . The experimental procedure was as
described for the preparation of 1 (SbCl ) . Quantities: 20 (320 mg,
23 μmol), tris(4-bromophenyl)aminium hexachloroantimonate
1.054 g, 1.29 mmol). The mixture of CH Cl (20 mL) and MeCN
6 mL) was used as a solvent. The resulting precipitate was filtered,
washed and dried in vacuo to afford 2 (SbCl ) (417 mg, 251
(m, 10H), 7.49−7.52 (m, 8H); C NMR (100 MHz, CDCl ) δ = 14.0
(s), 19.4 (s), 26.16 (s), 26.21 (s), 29.4 (s), 29.5 (s), 29.6 (s), 29.7 (s),
6
2
3
2+
−
6
2
3
(
(
3
(
1
(
1.5 (s), 50.3 (s), 67.5 (s), 67.9 (s), 68.2 (s), 71.1 (s), 114.8 (s), 122.2
s), 122.5 (s), 123.6 (s), 124.40 (s), 124.44 (s), 124.5 (s), 126.1 (s),
26.2 (s), 127.0 (s), 129.0 (s), 129.1 (s), 130.1 (s), 131.1 (s), 136.99
s), 137.03 (s), 138.8 (s), 144.7 (s), 148.6 (dd, J = 16 Hz, 249 Hz),
2
2
2+
−
6
2
1
+
μmol): yield 78%; brown powder; mp 227−231 °C; H NMR (400
1
59.25 (s), 159.28 (s); HR-MS (APCI) C H F O S [M − H] calcd
84
85
4
6 6
MHz, CD Cl ) δ = 0.98 (t, J = 7.4 Hz, 6H), 1.45−1.54 (m, 4H), 1.74−
m/z 1457.4601, found m/z 1457.4602.
2
2
1
8
4
1
1
1
.81 (m, 4H), 4.01 (t, J = 6.5 Hz, 4H), 6.45−6.49 (m, 2H), 6.98 (d, J =
.6 Hz, 4H), 7.12−7.15 (m, 2H), 7.46 (d, J = 8.6 Hz, 4H), 7.96 (s,
H), 8.54 (s, 4H), 8.59 (s, 2H); 13C NMR (100 MHz, CD Cl ) δ =
1
-(8-Methacryloyloxyoctyl-1-oxy)-4-[2,3-difluoro-4-(4-
butoxyphenyl)phenyl]benzene (22). Alcohol 10 (1.01 g, 2.09
mmol) and Et N (438 mg, 4.33 mmol) were dissolved in THF (30
mL) at 0 °C. Then methacryloyl chloride (540 mg, 5.17 mmol) was
added to the solution, and the mixture was stirred for 4.5 h. The
reaction mixture was quenched with water and extracted with CH Cl2
three times. The combined organic extracts were washed with water
and brine, dried over Na SO , filtered, and concentrated. The crude
product was purified by column chromatography (silica gel, eluent:
CH Cl /hexane = 3/1) to afford acrylate 22 (776 mg, 1.41 mmol):
2
2
3
3.7 (s), 19.3 (s), 31.3 (s), 68.0 (s), 114.9 (s), 118.9 (s), 119.0 (s),
24.49 (s), 124.50 (s), 124.53 (s), 125.39 (s), 125.40 (s), 125.53 (s),
25.55 (s), 125.56 (s), 126.8 (s), 130.2 (d, J = 3 Hz), 132.2 (s), 132.7
s), 132.9 (s), 133.0 (s), 139.0 (s), 139.2 (s), 140.5 (s), 143.37 (d, J =
Hz), 143.39 (d, J = 1 Hz), 160.1 (s), 184.4 (s); HR-MS (APCI)
C H O F S [M − 2Sb12Cl] calcd m/z 988.1283, found m/z
88.1276.
Compound 2. The experimental procedure was as described for
the preparation of 1. Quantities: 2 (SbCl ) (237 mg, 143 μmol), Zn
powder (226 mg, 1.68 mmol). The mixture of CH CN (10 mL) and
2
(
1
2
4
+
5
4
40
2 4 6
9
2
2
yield 68%; white waxy solid; phase transition temperature/°C (DSC
on second heating) Cr 81 SA 116 N 136 I; H NMR (400 MHz,
CDCl ) δ = 1.00 (t, J = 7.5 Hz, 3H), 1.39−1.57 (m, 10H), 1.65−1.71
2+
−
1
6 2
3
3
THF (10 mL) was used as a solvent. The crude product was purified
by column chromatography (alumina, eluent: toluene/hexane = 2/3
followed by 3/1) to give 2 (91 mg, 92 μmol): yield 64%; white solid;
(
m, 2H), 1.77−1.85 (m, 4H), 1.95 (dd, J = 1.0 Hz, J = 1.4 Hz, 3H),
4
2
4
.01 (t, J = 6.4 Hz, 2H), 4.03 (t, J = 6.5 Hz, 2H), 4.15 (t, J = 6.7 Hz,
H), 5.54−5.56 (m, 1H), 6.09−6.11 (m, 1H), 6.97−7.01 (AA’BB’,
H), 7.19−7.21 (m, 2H), 7.50−7.53 (AA’BB’, 4H); C NMR (100
1
mp 250−252 °C; H NMR (400 MHz, CDCl ) δ = 0.99 (t, J = 7.4 Hz,
13
3
6
6
7
3
H),1.47−1.56 (m, 4H), 1.76−1.83 (m, 4H), 4.00 (t, J = 6.5 Hz, 4H),
MHz, CDCl ) δ = 14.0 (s), 18.5 (s), 19.4 (s), 26.07 (s), 26.12 (s), 28.7
3
.62 (brs, 2H), 6.91 (d, J = 8.5 Hz, 6H), 7.01−7.08 (m, 8H), 7.24−
(
1
(
s), 29.3 (s), 29.36 (s), 29.39 (s), 31.5 (s), 64.9 (s), 67.9 (s), 68.1 (s),
14.8 (s), 124.4 (s), 124.4 (s), 124.5 (s), 125.3 (s), 127.00 (s), 127.04
s), 127.1 (s), 129.1 (d, J = 3 Hz), 130.1 (s), 136.7 (s), 148.6 (dd, J =
13
.35 (m, 6H); C NMR (125 MHz, CDCl ) δ = 14.0 (s), 19.4 (s),
3
1.5 (s), 67.9 (s), 114.6 (s), 121.31 (s), 121.34 (s), 124.2 (s), 124.3 (d,
J = 5 Hz), 124.5 (d, J = 5 Hz), 125.5 (s), 125.8 (s), 126.6 (s), 128.0
s), 130.1 (s), 136.5 (s), 159.2 (s); HR-MS (ESI) C H O F S [M +
H] calcd m/z 989.1367, found m/z 989.1342.
Dication Salt 3 (SbCl ) . The experimental procedure was as
−1
2
1
5
49 Hz, J = 15 Hz), 159.26 (s), 159.30 (s), 167.7 (s); IR (KBr, cm )
(
+
54 41
2 4 6
720 (ν CO); HR-MS (ES) C H F O Na [M + Na] calcd m/z
+
34
40
2
4
73.2792, found m/z 573.2802.
2+
−
2+
−
6
2
Dication Salt 1 (SbCl ) . To a solution of 19 (114 mg, 99.7
2+
−
6
2
described for the preparation of 1 (SbCl ) . Quantities: 21 (76 mg,
6 2
μmol) in CH Cl2 (5 mL)/MeCN (0.2 mL) was added tris(4-
2
52 μmol), tris(4-bromophenyl)aminium hexachloroantimonate (171
mg, 209 μmol). The mixture of CH Cl (4 mL) and MeCN (1.5 mL)
bromophenyl)aminium hexachloroantimonate (326 mg, 399 μmol) at
room temperature, and the mixture was stirred for 3 h. To the reaction
mixture was added ether (100 mL). The precipitate was filtered,
washed and dried in vacuo to afford 1 (SbCl ) (61 mg, 87.3 μmol):
yield 88%; brown powder; mp 195−200 °C (dec.); H NMR (400
MHz, CD CN) δ = 0.99 (t, 7.4 Hz, 6H), 1.45−1.55 (m, 4H), 1.74−
2
2
was used as solvent. The resulting precipitate was filtered, washed and
dried in vacuo to afford 3 (SbCl ) (99 mg, 47 μmol): yield 90%;
brown powder; phase transition temperature/°C (DSC on second
heating) Cr 78 S 122 I; H NMR (400 MHz, CD Cl ) δ = 0.99 (t, J =
7.4 Hz, 6H), 1.04−1.29 (m, 16 H), 1.35−1.56 (m, 8H), 1.71−1.83 (m,
H), 3.30 (t, J = 6.5 Hz, 4H), 3.99 (t, J = 6.4 Hz, 4H), 4.02 (t, J = 6.5
2+
−
6
2
2+
−
6
2
1
1
X
2
2
3
1
7
.81 (m, 4H), 4.05 (t, J = 6.5 Hz, 4H), 7.01−7.05 (AA’BB’, 4H),7.06−
.09 (AA’BB’, 4H), 7.27−7.36 (m, 4H), 7.47 (d, J = 8.4 Hz, 4H), 7.54
8
2
2
Hz, 4H), 4.35 (d, J = 12 Hz, 2H), 4.37 (d, J = 12 Hz, 2H), 6.97−7.01
(
d, J = 8.4 Hz, 4H), 7.91−7.96 (m, 4H), 8.41−8.43 (m, 4H), 8.73 (s,
(AA’BB’, 8H), 7.21−7.26 (AA’BB’, 4H), 7.50−7.54 (m, 8H), 7.90−
H); 13C NMR (125 MHz, CD CN) δ = 14.1 (s), 19.9 (s), 31.9 (s),
8.6 (s), 115.6 (s), 125.71 (s), 125.73 (s), 125.80 (s), 125.82 (s),
27.1 (s), 128.6 (s), 128.7 (s), 129.1 (s), 130.2 (d, J = 2 Hz), 131.0 (d,
13
2
6
1
7.92 (m, 4H), 8.40−8.42 (m, 4H), 8.57 (s, 2H); C NMR (100 MHz,
3
CD Cl ) δ = 13.8 (s), 19.4 (s), 26.1 (s), 29.31 (s), 29.34 (s), 29.4 (s),
2
2
29.7 (s), 31.4 (s), 66.8 (s), 68.0 (s), 68.2 (s), 72.0 (s), 114.8 (s), 124.6
(s), 124.59 (s), 124.60 (s), 124.64 (s), 126.5 (s), 130.1 (d, J = 3 Hz),
130.2 (d, J = 3 Hz), 131.9 (s), 132.1 (s), 140.7 (s), 141.8 (s), 143.7
(s), 159.3 (s), 159.5 (s), 184.9 (s); HR-MS (ES) C H O F S [M −
J = 2 Hz), 132.1 (s), 132.7 (s), 133.0 (s), 136.2 (s), 139.6 (s), 141.9
s), 142.3 (s), 146.4 (s), 160.3 (s), 187.1 (s); HR-MS (APCI)
(
+
C H O F S [M − 2Sb12Cl + H] calcd m/z 1141.1987, found m/z
66
49
2
4
6
84 84
6 4 6
2+
1141.1979.
Sb Cl ] calcd m/2z 728.2264, found m/2z 728.2289.
2 12
K
dx.doi.org/10.1021/jo501072u | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
Compound 3. The experimental procedure was as described for
ASSOCIATED CONTENT
2+
−
■
the preparation of 1. Quantities: 3 (SbCl ) (277 mg, 130 μmol), Zn
6
2
*
S
Supporting Information
powder (110 mg, 1.68 mmol). The mixture of dry CH Cl (5 mL) and
2
2
Copies of H and 13C NMR spectra for all compounds, GPC
chart of LCP, cyclic voltammogram of 18, Spectroelectrochem-
ical studies of 1 and 3, phase diagram of complexes of 3/7,
polarized micrographs of complex of 2/7, XRD patterns for
LCP and other complexes (1/LCP, 2/LCP, BDTBT/LCP,
1
THF (3 mL) was used as solvent. The crude product was purified by
column chromatography (alumina, eluent: CH Cl /hexane = 2/3
2
2
followed by 1/1) to give 3 (98 mg, 67.2 μmol): yield 52%; ivory solid;
phase transition temperature/°C (DSC on first cooling) I 107 N 103
S 87 S 59 Cr; (DSC on second heating) Cr 87 S 106 S 115 N 122
A
E
E
A
1
2+
2+
2+
I; H NMR (500 MHz, CDCl ) δ = 0.99 (t, J = 7.3 Hz, 6H), 1.25−
1 /LCP, 2 /LCP, and BDTBT /LCP), and crystal data
(CIF). This material is available free of charge via the Internet
at http://pubs.acs.org.
3
1
6
2
4
.55 (m, 24 H), 1.73−1.83 (m, 8H), 3.31−3.41 (m, 4H), 3.94 (td, J =
2
.5 Hz, J = 2.1 Hz, 4H), 4.01 (t, J = 6.3 Hz, 4H), 4.58 (d, J = 13 Hz,
2
H), 4.74 (d, J = 13 Hz, 2H), 6.93−7.00 (m, 16H), 7.18−7.19 (m,
H), 7.33 (s, 2H), 7.48−7.51 (m, 8H); C NMR (100 MHz, CDCl )
13
3
AUTHOR INFORMATION
■
δ = 14.0 (s), 19.4 (s), 26.1 (s), 26.2 (s), 29.4 (s), 29.46 (s), 29.52 (s),
0.0 (s), 31.5 (s), 67.9 (s), 68.2 (s), 68.5 (s), 70.2 (s), 80.1 (s), 114.8
s), 121.1 (s), 121.2 (s), 124.40 (s), 124.44 (s), 124.5 (s), 125.4 (s),
25.58 (s), 125.62 (s), 126.97 (d, J = 1 Hz), 127.00 (d, J = 1 Hz),
28.99 (s), 129.04 (s), 129.1 (d, J = 2 Hz), 130.10 (s), 130.11 (s),
31.2 (s), 136.6 (s), 138.3 (s), 139.0 (s), 143.5 (s), 148.6 (dd, J = 16
Corresponding Authors
*E-mail: otake.toshihiro@exc.epson.co.jp.
*E-mail: aohta@shinshu-u.ac.jp.
3
(
1
1
1
Notes
The authors declare no competing financial interest.
Hz, J = 250 Hz), 159.26 (s), 159.29 (s); HR-MS (APCI)
+
C H O F S [M] calcd m/z 1456.4523, found m/z 1456.4533.
8
4
84
6
4
6
2
+
−
ACKNOWLEDGMENTS
1
(SbCl ) by the Oxidation of 1. To a solution of 1 (47 mg,
■
6
2
4
1 μmol) in the mixture of CH Cl (2 mL) and MeCN (0.1 mL) was
We thank Sumika Chemical Analysis Service (SCAS) for
measurements of high-resolution mass spectrometry. We thank
Reina Hirose (SEIKO EPSON), Etsuko Takei (SEIKO
EPSON), and Tomohiro Fujita (SEIKO EPSON) for measure-
ments of high-resolution mass spectrometry. Rie Miyazaki
2
2
added tris(4-bromophenyl)aminium hexachloroantimonate (68 mg, 83
μmol) at room temperature, and the mixture was stirred for 4 h. To
the reaction mixture was added ether (40 mL). The precipitate was
2+
−
filtered, washed and dried in vacuo to afford 1 (SbCl ) (54 mg, 30
6
2
μmol): yield 73%.
(
SEIKO EPSON) is thanked for GPC measurements. We are
2+
−
2
(SbCl ) by the Oxidation of 2. To a solution of 2 (41 mg,
6 2
also grateful to Dr. Satoshi Inoue (SEIKO EPSON) and Dr.
Masahiro Furusawa (SEIKO EPSON) for helpful discussions.
We thank the Instrument Center of the Institute of Molecular
Science for X-ray structural analysis.
4
1 μmol) in CH Cl2 (2.5 mL) was added tris(4-bromophenyl)-
2
aminium hexachloroantimonate (68 mg, 83 μmol) at room temper-
ature, and the mixture was stirred for 2 h. To the reaction mixture was
added ether (40 mL). The precipitate was filtered, washed and dried in
2
+
−
vacuo to afford 2 (SbCl ) (53 mg, 32 μmol): yield 78%.
6
2
2+
−
3
(SbCl ) by the Oxidation of 3. The experimental procedure
was as described for the preparation of 2 (SbCl ) . Quantities: 3 (78
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6
2
■
(
2+
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(
77
SIR2004. All non-hydrogen atoms were refined anisotropically by
2
78
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9
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40
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7
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L
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