Effect of alkoxy terminal chain length on mesomorphism of 1,6-disubstituted pyrene-based hexacatenar liquid crystals: Columnar phase control

Article abstract of DOI:10.1016/j.tet.2014.05.111

Synthesis and mesophase-transition behaviors of six 1,6-disubstituted pyrene-based hexacatenar liquid crystals 1_n (n=8-18) are reported here. They were synthesized by the Sonogashira coupling between 1,6-diethynylpyrene and 2-bromothiophene bearing a trialkoxybenzoyl group. The phase-transition behavior was studied by differential scanning calorimetry and polarized optical microscopy; a few mesophase progressions, I-Col/I-X-Col and Col-Sm, were observed, where X was an optically isotropic but unidentified phase. The structures of Col_r, Col_h, and Sm phases were analyzed by the X-ray crystallography, and the effect of the terminal alkoxy chain length on the mesomorphism was evaluated.

Full text of DOI:10.1016/j.tet.2014.05.111

Tetrahedron 70 (2014) 5100e5108
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Effect of alkoxy terminal chain length on mesomorphism of
1,6-disubstituted pyrene-based hexacatenar liquid crystals:
columnar phase control
,
a
a
b
Takuji Hirose a , Hiroaki Takai , Mizuki Watabe , Hiroyuki Minamikawa ,
*
Tatsuya Tachikawa a, Koichi Kodama a, Mikio Yasutake c
a Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama, Saitama 338-8570, Japan
b Nanotechnology Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba Central-5, Higashi 1-1-1, Tsukuba,
Ibaraki 305-8565, Japan
c Comprehensive Analysis Center for Science, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama, Saitama 338-8570, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
Synthesis and mesophase-transition behaviors of six 1,6-disubstituted pyrene-based hexacatenar liquid
crystals 1n (n¼8e18) are reported here. They were synthesized by the Sonogashira coupling between 1,6-
diethynylpyrene and 2-bromothiophene bearing a trialkoxybenzoyl group. The phase-transition behavior
was studied by differential scanning calorimetry and polarized optical microscopy; a few mesophase
progressions, IeCol/IeXeCol and ColeSm, were observed, where X was an optically isotropic but un-
identified phase. The structures of Colr, Colh, and Sm phases were analyzed by the X-ray crystallography,
and the effect of the terminal alkoxy chain length on the mesomorphism was evaluated.
Ó 2014 Elsevier Ltd. All rights reserved.
Received 14 March 2014
Received in revised form 29 May 2014
Accepted 31 May 2014
Available online 11 June 2014
Keywords:
Hexacatenar liquid crystal
Mesomorphism
Columnar phase
Pyrene derivatives
1. Introduction
be effective for increasing the photoconductivity and solubility in
common organic solvents.5a
Liquid crystals are soft materials that spontaneously form sev-
eral types of ordered structures and thermally change their physi-
cochemical properties.1 Currently, their self-organization has
attracted great attention and has been exploited in the synthesis of
nanostructures for diverse applications similar to those of poly-
mers.2 Low-molecular-weight liquid crystals are particularly ad-
vantageous for a relatively easy designing of the structure and
function.
Recently, several research groups have reported the de-
velopment of liquid crystals containing a pyrene unit.3 Pyrene is
widely used for constructing diverse photoactive molecules and
photofunctional materials.4 We studied tetrasubstituted pyrene-
based liquid crystals for developing conductive columnar liquid
crystals with one-dimensional conductivity.5 A relatively small ar-
omatic structure was chosen as the core moiety to lower the
mesophase-transition temperature. To improve the reduced con-
Polycatenar liquid crystals comprise an interesting class of
thermotropic liquid crystals1d,4b,d,6 with molecular features in-
termediate between those of rod-like and disc-like liquid crystals.
Polycatenar liquid crystals show smectic, columnar, and cubic
phases depending on the size and length of the building blocks.
Recently, a couple of conductive cubic phases have been reported.7
Therefore, it seems interesting to study and compare the conduc-
tivities in various liquid crystalline phases of polycatenar liquid
crystals. In addition, they may afford a synthetically facile method
to achieve functional columnar liquid crystals.
ductivity owing to its small p-conjugated system, appropriate side
chains and substituents were investigated. In the previous study,
peripheral trialkylsilyl group with a long alkyl chain was found to
In this paper, we report the synthesis and mesomorphism of six
1,6-disubstituted pyrene-based hexacatenars, 1n. Several types of
mesophase structures such as rectangular (Colr) and hexagonal
(Colh) columnar phases, smectic phase (Sm), and an unidentified
* Corresponding author. E-mail addresses: thirose@mail.saitama-u.ac.jp, hirose@
apc.saitama-u.ac.jp (T. Hirose).
http://dx.doi.org/10.1016/j.tet.2014.05.111
0040-4020/Ó 2014 Elsevier Ltd. All rights reserved.

T. Hirose et al. / Tetrahedron 70 (2014) 5100e5108
5101
isotropic phase appeared, depending on the terminal alkoxy chain
2.2. Mesophase transitions
length. To investigate the reason of their non-photoconductivity,
the spectroscopic and electronic properties were also studied.
The phase-transition behaviors of 1n (n¼8, 10, 12, 14, 16, and 18)
were examined by differential scanning calorimetry (DSC) and
polarized optical microscopy (POM). The results of the cooling
process are summarized in Table 1, and those of the heating process
are summarized in Table S1.
2. Results and discussion
2.1. Design and synthesis
Table 1
1,6-Disubstituted pyrene derivatives, 1n (n¼8, 10, 12, 14, 16, and
18), were designed by combining an ethynylthiophene moiety and
a trialkoxybenzoic acid moiety. Although the ethynyl group is an
electron-withdrawing group, ethynylthiophene was chosen to ex-
Phase-transition behaviors of 1n (n¼8, 10, 12, 14, 16, and 18) on the cooling process
Compound
Phase-transition temperatures (ꢀC) and enthalpies
a
(kJ molꢁ1
)
18
I 129 (34) Colr [50]b ColrþSm
110
112
114
116
118
I [126 X 119]c (38) Colr
pand the
p-conjugation of the core. Actually arylethynyl pyrenes
usually show red shift, i.e., smaller HOMOeLUMO energy gap;8
therefore, ethynylthiophene is often used as conductive materials
such as oligo- and polythiophene and vinylthiophene deriva-
tives.6a,9 In contrast, the trialkoxybenzoyl moiety was chosen not
only to introduce flexibility to the molecule but also to induce co-
lumnar structures among some mesophases.1d
I [122 X 104]c (41) Colrꢁ5 (37) Sm
I 120 (24) X 76 (4) Colr 20 (52) Sm
I 121 (24) X 69 (6) Colr 35 (71) Sm
I 120 (24) X 64 (4) Colh 46 (89) Sm
Abbreviations: I¼isotropic phase; Colr¼rectangular columnar phase; Colh¼hexag-
onal columnar phase; Sm¼smectic phase; X¼unidentified phase.
a
Transition temperatures (ꢀC) and transition enthalpies (kJ molꢁ1, given in pa-
rentheses) determined by DSC (2 ꢀC minꢁ1).
The syntheses of 1n are shown in Schemes 1 and 2; the side chain
moieties, 7n, were prepared from methyl gallate in the following five
steps in good to high yields (Scheme 1): (i) protecting the hydroxyl
groups by methylation;10 (ii) hydrolyzing the methyl ester;11 (iii)
chlorinating the carboxyl acid group followed by coupling with 2-
bromothiophene by FriedeleCrafts reaction;12 (iv) deprotecting
the hydroxyl groups;11,13 and (v) performing Williamson ether
synthesis with the corresponding alkyl bromide (n-CnH2nþ1Br).10,11
To prepare the core moiety, pyrene was first brominated to afford
a mixture of 1,6- and 1,8-dibromopyrenes.14 The mixture was
chromatographed to isolate 1,6-dibromopyrene, which was then
coupled to 2-methyl-3-butyn-2-ol under Sonogashira reaction and
basic conditions to afford 12.3d Finally, 7n and 12 were subjected to
Sonogashira coupling reaction conditions to afford 1n.
b
Transition temperatures (ꢀC) determined by XRD.
Two phase-transition peaks are inseparable.
c
When 18 was cooled from its isotropic liquid phase temperature,
the first phase transition was observed at 129 ꢀC in both the DSC
(Table 1) and POM measurements. Although 18 formed needle-
shaped spherical aggregates with pompon-like structure (Fig. S1(a-
1)) that looked like crystals, it was easily crushed by pressing and
then showed fluidity; therefore, this phase was tentatively assigned
as a columnar (Col) phase. The second phase transition was clearly
observed by the DSC measurement at w50 ꢀC (Table 1); however, it
could not be observed by the POM measurement. The texture of the
Scheme 1. Synthesis of 2-bromo-5-(3,4,5-trialkoxybenzoyl)thiophene 7n (n¼8e18). (a) Me2SO4, K2CO3/CH3CN; (b) KOH (s)/EtOH; (c) 1 M HCl; (d) SOCl2; (e) 2-bromothiophene,
AlCl3/dry CH2Cl2; (f) 1 M BBr3 in CH2Cl2/dry CH2Cl2; (g) CnH2nþ1Br, K2CO3, cat. NaI/acetone.
Scheme 2. Synthesis of 1,6-diethynylpyrene and 1n (n¼8e18). (a) Br2/CCl4; (b) 2-methyl-3-butyn-2-ol, cat. PdCl2(PPh3)2, cat. CuI/dry toluene, Et2NH; (c) NaOH(s)/dry toluene; (d)
7n, cat. PdCl2(PPh3)2, cat. CuI/dry toluene, Et2NH.

5102
T. Hirose et al. / Tetrahedron 70 (2014) 5100e5108
phase observed was almost the same as that of the Col phase except
for a slight color change Fig. S1(a-2).
phase was optically isotropic, as shown in Fig. 2 for 112 (a-1), 116 (b-
1), and 118 (c-1) (Fig. S1(c-1) for 114), which was named as un-
identified phase ‘X’.
In the cooling run, 110 exhibited a texture similar to that of
pompons in a wide temperature range below 119 ꢀC (Fig. S1(b-2)).
In addition, in a higher and narrower temperature range (i.e., be-
tween 126 and 119 ꢀC), an optically isotropic phase was found by
careful observation, and the transition temperature was recognized
as a small exothermic peak in the DSC curve (Fig. 1 and Table 1). The
optically isotropic phase was also found in 1n with longer alkoxy
chains than 110 as described in the next paragraph.
On further cooling, the second transition appeared in the DSC
measurement, and the texture changed from the pompon-like (112
:
Fig. 2a-2) to spherulitic (116: Fig. 2b-2) or focal conic (118: Fig. 2c-2)
phase, as observed by the POM (114: Fig. S1(c-2)), indicating the Col
phases.
The third phase-transition was clearly observed by the DSC
measurement (118: Fig. 1, 18, 112, 114, and 116: Fig. S2). The texture
change was observed for 116 and 118 (Fig. 2b-3 and c-3). Despite the
difference in the appearance, all phases were firm, and the fluidity
was not confirmed during the POM observations. The structural
characterization was carried out by the temperature-dependent X-
ray diffraction (XRD) study, as described later.
2.3. Mesophase structures
The DSC and POM measurements indicated that 18e118 exhibit
Col phases in a lower wide temperature range, whereas 110e118
exhibit isotropic unidentified phase X in a higher, narrower tem-
perature range. However, the phase structures were not fully
characterized from the observed textures only. To establish the
thermal properties of the liquid crystals, all 1n samples were ana-
lyzed by XRD study. Figs. 3e5 show the XRD patterns of 18, 116, and
118, respectively; the XRD data of 1n are summarized in Table 2.
Fig. 3a shows a broad peak, halo, at 2
q
¼w20ꢀ corresponding to
the molten alkoxy chains and six peaks (three sharp peaks at 39.6,
ꢀ
ꢀ
33.2, and 19.5 A and three small peaks at 16.5, 13.2, and 12.7 A) in
the small-angle region for 18 at 115 ꢀC. These diffractions and their
pattern are characteristic of Colr (P21/a) phase, corresponding to the
results of the POM observation. Assuming that the two largest
peaks at small angle are ascribed to (110) and (200),15 the lattice
ꢀ
ꢀ
constants were calculated as 66.4 A (a) and 49.4 A (b) (Table 2).
Fig. 1. DSC traces of 110 and 118. Heating and cooling rates were 2 ꢀC/min.
However, these figures seem to be too large considering the mo-
lecular size of 18 (w47 A). In fact, they afforded the apparent unit
ꢀ
For 112, 114, 116, and 118, the exothermic peak was observed at
number of the unit cell as 7.1, even though the unit number Z of P21/
w120 ꢀC in the DSC measurement, as shown in Fig. 1 for 118
.
a should be 2. Therefore, the number of molecules in the disc,
m, was
However, no change or orientation was detected by the POM
measurement using either homogeneous or homeotropic cells not
only on cooling the melt but also repeated thermal treatment; the
calculated by Eq. 1 assuming that the intramolecular periodicity
was 5 A
4d,6b,c
ꢀ
and the density was 1 g/cm3.6d,15
Y ¼ Z$
m
¼ NA$V$
r
=M
(1)
where Y is the number of molecules in the unit cell, Z is the number
of disc in the unit cell, NA is the Avogadro’s constant, V is the volume
of the unit cell, and
the liquid crystal, respectively. As
r
and M are the density and molecular weight of
was obtained as 3.5 (Table 2), it
m
was shown that the discotic unit of the Colr should be composed of
3e4 molecules of 18 (Fig. 6).
At 50 ꢀC, two new diffractions were obtained with a quite
similar peak pattern of Colr, and they could be ascribed to (001)
(38.4 A) and (002) (18.7 A) (Fig. 3b).15 Considering the analysis of 1n
(n¼12e18) as discussed later, a smectic structure was expected to
appear (The other peaks of Colr (P21/a) are assigned as summarized
in Table S2.). At 0 and ꢁ50 ꢀC, the diffraction pattern was similar to
that at 50 ꢀC, but the intensity lowered (Fig. 3c). Therefore, the
phase seemed to gradually change from the columnar to glassy
states; however, it could not be confirmed because no such tran-
sition was observed by the DSC measurements.
ꢀ
ꢀ
The XRD patterns of 110 at several temperatures (Fig. S3) were
also similar to those shown of 18 in Fig 3; however, no indication of
a smectic feature was found. Therefore, the mesophase structure
Colr (P21/a) and the lattice constants were determined as shown in
Table 2.
The DSC measurements revealed that 112e118 exhibit an opti-
cally isotropic phase in a high-temperature range; however, the
Fig. 2. Polarized optical micrographs of 112, 116, and 118 at several temperatures.

T. Hirose et al. / Tetrahedron 70 (2014) 5100e5108
5103
Fig. 4. XRD patterns of 116 at several temperatures. (a) 135 and 100 ꢀC, (b) 60 ꢀC, (c) 4
and ꢁ10 ꢀC.
for 116. According to the XRD patterns and the discussion reported
previously,16 the present phase could not be identified and was thus
named as unidentified phase X.
On further cooling, the phase-transition of 116 showed several
ꢀ
sharp peaks (three sharp peaks at 43.3, ꢀ41.7, and 21.9 A and three
Fig. 3. XRD patterns of 18 at several temperatures. (a) 115 ꢀC, (b) 50 ꢀC, (c) 50, 0, and
ꢁ50 ꢀC.
ꢀ
small peaks at 31.8, 12.1, and 11.0 A at 60 C), which can be assigned
to Colr (P21/a) (Fig. 4b), similar to 18, 112, and 114. The XRD data are
summarized in Table 2, including those of 112 and 114 (Figs. S4b and
S5b for the XRD patterns). On the other hand, 118 showed two sharp
peaks at 43.3 A (100) and 21.8 A (200) at 60 ꢀC, and a halo at
ꢀ
ꢀ
phase was not distinguished from the isotropic liquid phase in the
POM study (112, 116, and 118: Fig. 2, 114: Fig. S1c). To study this phase,
2q
¼w20ꢀ (Fig. 5b). The spacing ratio of the sharp peaks was 1:1/2
indicating the phase was Colh (P6mm) (Table 2).15 Although the disc
unit might contain three molecules as other 1n (n¼8e16), it was
shown that the alkoxy chain elongation to 118 caused the columnar
structure from Colr to Colh.
112, 116, and 118 were analyzed by small-angle XRD (Figs. S4a, 4a,
and 5a, respectively). However, all the figures show only a couple
of halos, and no sharp peaks appeared after the annealing process,
e.g., even after two-day annealing at 100 ꢀC, no peak was observed

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T. Hirose et al. / Tetrahedron 70 (2014) 5100e5108
Table 2
XRD data of hexacatenar 1n (n¼8, 10, 12, 14, 16, and 18)
ꢀ
Compound Mesophase lattice
Spacing/A
Miller indices (hkl)
ꢀ
constants/A
Observed Calculated
1
8 (n¼8)
Colr (P21/a) at 115 ꢀC 39.6
39.6
33.2
19.8
16.6
13.2
12.8
(110)
(200)
(220)
(400)
(330)
(510)
(001)
(002)
(110)
(200)
(210)
(310)
(220)
(320)
(420)
(330)
(110)
(200)
(310)
(220)
(410)
(001)
(110)
(200)
(220)
(320)
(240)
(340)
(001)
(100)
(110)
(200)
(210)
(220)
(240)
(440)
(001)
(100)
(100)
(200)
a¼66.4
b¼49.4
h¼5.0a
33.2
19.5
16.5
Z¼2,
m
¼3.5 for
r
¼1.0b 13.2
12.7
Sm at 50 ꢀC
38.4
18.7
110 (n¼10) Colr (P21/a) at 115 ꢀC 40.5
40.5
35.0
28.6
21.1
20.3
17.0
14.3
13.5
40.5
36.5
21.8
20.3
17.1
a¼70.1
b¼49.6
h¼5.0a
35.0
28.5
21.0
Z¼2,
m¼3.4 for
r
¼1.0b 20.2
16.8
14.1
13.2
112 (n¼12) Colr (P21/a) at 95 ꢀ
C
40.5
36.5
21.7
20.3
a¼73.0
b¼48.7
h¼5.0a
Z¼2,
m
¼3.1 for
r
¼1.0b 16.7
Sm at ꢁ40 ꢀC
38.5
114 (n¼14) Colr (P21/a) at 55 ꢀ
C
39.4
36.8
20.5
16.5
39.4
36.8
19.7
16.9
11.1
10.5
a¼73.6
b¼46.7
h¼5.0a
Z¼2,
m¼2.7 for
r
¼1.0b 11.3
10.4
Sm at ꢁ10 ꢀC
37.6
4.1
116 (n¼16) Colr (P21/a) at 60 ꢀ
C
43.3
41.7
31.8
21.9
43.3
41.7
32.2
21.6
12.1
10.8
a¼83.3
b¼50.7
h¼5.0a
Z¼2,
m¼3.1 for
r
¼1.0b 12.1
11.0
Sm at 4 ꢀC
40.9
4.1
118 (n¼18) Colh (P6mm) at 60 ꢀ
C
43.3
21.8
43.3
21.6
a¼50.0
h¼5.0a
Z¼1,
m
¼2.9 for
r
¼1.0b
Sm at 40 ꢀC
43.1
4.2
(001)
(100)
a
Assumed stacking distance.
Assumed density (g cmꢁ3).
b
Fig. 5. XRD patterns of 118 at several temperatures. (a) 135 and 100 ꢀC, (b) 60 ꢀC, (c) 40,
20, and ꢁ40 ꢀC.
Fig. 6. Schematic structure of Colr (P21/a) containing three molecules of 1n (n¼8e16)
in a discotic unit.
Thus, 110 exhibits the widest temperature range, >170 K from
the DSC and >200 K from the XRD measurements, in the Col phase;
further elongation of the alkoxy chain narrows the phase region.
the absorption and emission maxima and the optical band gaps
(D
Eopt) are summarized in Table 3 along with those of pyrene.17a
2.4. Redox and spectroscopic properties
The introduction of electron-donating alkyl groups to a pyrene
core causes a stepwise bathochromic shift.17a Although an ethynyl
group is electron-withdrawing, the present disubstituted com-
pounds showed the lmax and lem values at longer wavelengths
w440 and w510 nm, at lower HOMO and LUMO levels, re-
spectively, than those of di- and tetrabutylpyrenes.17a The in-
troduction of the group seems to largely contribute to the
The spectroscopic properties of 1n (n¼8, 12, and 16) were
measured in dichloromethane; the UVevis and emission spectra of
1
12 are shown in Fig. 7. Both the spectra show similar features as the
pyrene derivatives with ethynyl3bed,4b or electron-donating
groups;3g,17 the emission spectrum displays no structure. Almost
the same spectral pattern was obtained for 18 and 116 (Fig. S6); all
expansion of p
-conjugation. of 1n, as reported previously.3b,c,4b,17b

T. Hirose et al. / Tetrahedron 70 (2014) 5100e5108
5105
Fig. 7. The UVevis (a) and emission (b) spectra of 112. In dry CH2Cl2, 1ꢂ10ꢁ5 M.
As observed from the spectroscopic and electrochemical prop-
erties, 1n seem to have the designed properties, i.e., electrochemical
stability with a small HOMOeLUMO band gap, as expected for
those reported previously,4b,c,5b with charge-transport properties.
However, it was impossible to detect the time of flight of holes or
electrons in all the columnar phases of 1n. In contrast, charge mo-
bility changes depending on the phases of a liquid crystal18a and
phase transitions.4c,18bed Because the molecular arrangement and
movement largely affect the charge-transport ability, these results
can be explained by unfavorable molecular packing between the
neighboring discs, which are composed of 3e4 molecules of 1n as
mentioned above (Fig. 6).
Table 3
Spectroscopic data of 1n (n¼8, 12, and 16)a
n
lmax (nm)
lem (nm)
D
Eoptb (eV)
8
12
440
439
440
333
509
507
508
374
2.55
2.55
2.55
d
16
Pyrene15
a
1.0ꢂ10ꢁ5 M in deaerated CH2Cl2.
b
Optical band gap calculated from the onset of the absorption band.
The redox properties of 1n were characterized by cyclic vol-
tammetry (CV); the CV curve of 112 is shown in Fig. 8 (18 and 116
:
Fig. S7). The CV profile seems electrochemically stable and similar
to other pyrene derivatives.17 The HOMO and LUMO levels and
electrochemical band gaps,
D
E(LUMOꢁHOMO), were evaluated and
3. Conclusions
summarized in Table 4 with those of pyrene.17a All the electro-
chemical band gaps are w2.5 V for 1n (n¼8, 12, and 16) and com-
Six pyrene-based hexacatenars 1n (n¼8, 10, 12, 14, 16, and 18)
were prepared to construct columnar phase liquid crystals; their
thermal properties and mesomorphism were investigated using DSC,
POM, and XRD analyses. They form either the Colr or Colh phase
depending on the alkyl chain length (n-CnH2nþ1) of the terminal
trialkoxybenzoyl moiety; 1n (n¼8, 10, 12, 14, and 16) form the Colr
phase, whereas 118 forms the Colh phase. While 18 showed the
IeColeSm phase-transition during the cooling, 1n (n¼10, 12, 14, 16,
and 18) form an unidentified phase between the isotropic and co-
lumnar phases to give the IeXeColeSm transition and 110 exhibited
the widest temperature range of Col phase. They did not show any
charge-transport ability in the columnar phases, although all the
compounds displayed thermal and electrochemical stability and low
electrochemical band gaps. Compared to the pyrene-derived liquid
crystals with charge-transport ability,4b,c,5a it is expected that the
3e4 molecular packing of 1n in a disc does not allow effective charge
transport in the columnar structure. The related discotic molecules
are being developed using the results obtained in this study.
parable to the
DEopt values obtained from the corresponding
absorption spectra (Table 3). These compounds possess lower oxi-
dation potentials, w1 eV, than pyrene. Because the HOMO levels of
1n and pyrene are comparable, the difference between the lower
LUMO levels is more influential and is probably caused by the large
p-conjugation of the electron-donating functional groups.
4. Experimental section
4.1. General
Fig. 8. Cyclic voltammogram for 112. 1ꢂ10ꢁ3 M in deaerated CH2Cl2 containing 0.1 M of
n-Bu4NClO4, ꢁ1.8 V to þ1.2 V, Ag/Agþ
.
1HNMR (400 MHz)and13CNMR(100MHz)spectrawererecorded
on a Bruker DRX-400 spectrometer (Comprehensive Analysis Center
for Science (CACS), Saitama University). The chemical shift was re-
ported in parts per million (ppm) using tetramethylsilane as an in-
ternal standard. IR spectra were recorded on a JASCO FT/IR-460
spectrometer. UVevis and emission spectra of all compounds were
recorded as a dichloromethane solution on JASCO V-550.
Cyclic voltammetry was performed using an ALS CHI 611D
electrochemical analyzer. The measurements were carried out in
dichloromethane containing 0.1 M solution of n-Bu4NClO4 as sup-
porting electrolyte (scan rate: 200 mV sꢁ1) at room temperature.
The concentration of 1n was 1.0ꢂ10ꢁ3 M. Glassy carbon electrode
was used as the working electrode, a platinum wire as the counter
electrode, and Ag/AgNO3 electrode as the reference electrode. The
Table 4
Electrochemical properties of 1n (n¼8, 12, and 16)a
n
Eoxb (V) Eredb (V) HOMOc (eV) LUMOd (eV)
D
E(LUMOꢁHOMO) (eV)
8
12
16
1.01
1.01
1.02
ꢁ1.66
ꢁ1.63
ꢁ1.67
d
ꢁ5.51
ꢁ5.51
ꢁ5.53
ꢁ5.31
ꢁ3.02
ꢁ3.04
ꢁ3.01
ꢁ1.98
2.49
2.47
2.52
3.32
pyrene15 1.12
a
1.0ꢂ10ꢁ3 M in deaerated CH2Cl2 containing 0.10 M n-Bu4NClO4.
b
c
Potentials versus Ag/Agþ calibrated against Fc/Fcþ (0.208 V).
The
HOMO
was
determined
using
the
relationships
onset
HOMO ¼ ꢁðE
ꢁ EFc þ 4:8Þ eV where Eooxnset and EFc are the onset potential of
ox
oxidation and the half wave potential of ferrocene, respectively.
d
onset
red
The LUMO was determined using LUMO ¼ ꢁðE
ꢁ EFc þ 4:8Þ eV where Eroendset
is the onset potential of reduction.

5106
T. Hirose et al. / Tetrahedron 70 (2014) 5100e5108
Ag/AgNO3 reference electrode was calibrated against ferrocene/
ferrocenium redox couple.
MALDI-TOF mass spectra were measured with a Bruker Daltonics
Autoflex III (CACS). X-ray diffraction analysis of the phase X of 112,116,
and 118 was also performed on a quartz substrate using a Rigaku
drydichloromethane (33 ml) at 0 ꢀC and stirredat roomtemperature
for 5 h. After quenching the reaction with water, the solution was
extracted with chloroform. The organic layer was dried over anhyd
Na2SO4 and concentrated and the yellow residue was purified by
column chromatography (silica gel, chloroform/hexane¼30:1) to
obtain 5 (4.97 g, 13.9 mmol, 95.2%) as a yellow solid. 1H NMR
model Ultima III X-ray diffractometer with a monochromated CuK
a
radiation source (wavelength¼0.1542 nm, 40 kV, 40 mA) (CACS). For
small-angle X-ray scattering measurements, a sample was sealed in
a quartz capillary (Glas, 1.5 mm in outer diameter, 0.01 mm in wall
thickness). The X-ray diffraction experiment was performed on
(400 MHz, CDCl3):
d
7.45 (d,1H, J¼4.0 Hz), 7.15 (d,1H, J¼4.0 Hz), 7.10
(s, 2H), 3.94 (s, 3H), 3.91 (s, 6H).13C NMR (100 MHz, CDCl3):
d
185.84,
153.06, 144.77, 142.05, 134.52, 132.41, 131.07, 122.90, 106.66, 60.98,
56.32. IR (KBr) cmꢁ1: 3000.69, 2935.13, 2837.74, 1632.45, 1578.45,
1501.31,1460.81,1414.53,1341.25,1232.29,1186.01,1122.37,1034.62,
1008.59, 987.38, 860.10, 800.31, 767.53, 749.21, 652.79, 576.61,
504.29, 458.01, 434.87, 410.76. Mp 83e84 ꢀC.
a Rigaku R-AXIS IV X-ray diffractometer with Cu Ka radiation (40 kV,
30 mA; a flat camera, sample-to-camera length: 150.0 mm). The
specimen temperature was controlled with a Mettler FP82HT hot
stage within an accuracy of ꢃ0.4 ꢀC.
Melting points were determined with a Mitamura Riken Kogyo
MEL-TEMP instrument and reported uncorrected. Phase-transition
temperatures were determined using a Mac Science DSC-3100 dif-
ferential scanning calorimeter. A Nikon OPTIPHOT2-POL optical
polarized microscope equipped with a Mettler FP-82 hot stage and
a Mettler FP-90 central processor was used to characterize aniso-
tropic textures.
All reagents and solvents commercially available were pur-
chased from Wako Pure Chemical Inc., Kanto Chemical Inc., Tokyo
Kasei Kogyo Co., and Aldrich Chemicals Co., and were used as re-
ceived except dry tetrahydrofuran, dry toluene, dry dichloro-
methane, dry diethylamine. The dry solvents were prepared
according to the standard procedure.
4.2.4. Synthesis of 2-bromo-5-(3,4,5-trihydroxybenzoyl)thiophene
(6). Under nitrogen, BBr3 (1 M in dry dichloromethane, 47 ml) was
added dropwise to 5 (4.97 g, 13.9 mmol) in dry dichloromethane
(33 ml) at 0 ꢀC over 1 h and stirred at room temperature for 6 h.
After quenching the reaction with methanol, the solution was
partially concentrated and then added into water to obtain a brown
precipitate. The product was collected by filtration, washed with
cold methanol, diethyl ether, hexane, and chloroform in this order,
and dried to give 6 (4.09 g, 13.0 mmol, 93.5%) as a brown solid. 1H
NMR (400 MHz, DMSO-d6):
d
7.56 (d, 1H, J¼4.0 Hz), 7.44 (d, 1H,
J¼4.0 Hz), 6.92 (s, 2H). 13C NMR (100 MHz, DMSO-d6):
d 185.49,
146.75, 145.98, 139.94, 135.60, 132.94, 127.47, 121.76, 109.81. IR
(KBr) cmꢁ1: 3196.43, 1573.63, 1518.67, 1452.14, 1416.46, 1360.53,
1259.29, 1108.87, 1042.34, 992.20, 869.74, 811.89, 747.28, 640.25,
582.40, 552.51, 518.76, 488.87, 476.33, 448.37, 431.98, 417.51.
4.2. Synthesis
4.2.1. Synthesis of 3,4,5-trimethoxybenzoic acid methyl ester
(3).10 To a solution of methyl gallate 2 (2.95 g, 16.0 mmol) in CH3CN
(120 ml) were added K2CO3 (19.2 g, 0.139 mol) and Me2SO4 (6.59 g,
52.2 mmol) and refluxed for 48 h. The reaction mixture was filtered,
the filtrate was concentrated and the residue was extracted with
chloroform and water. After drying over anhyd Na2SO4, the organic
layer was concentrated to give a yellow solid. The crude product was
purified bycolumn chromatography (silica gel, chloroform) to obtain 3
(3.41 g,15.1 mmol, 94.4%) as a white solid. 1H NMR (400 MHz, CDCl3):
4.2.5. Synthesis of 2-bromo-5-(3,4,5-trioctyloxybenzoyl)thiophene
(78). To a solution of 6 (0.202 g, 0.640 mmol) in acetone (15 ml)
were added K2CO3 (3.48 g, 25.2 mmol), n-C8H17Br (0.608 g,
3.15 mmol), and NaI (9.44 mg, 63.0 mmol). After refluxing for 72 h,
the precipitate was removed by filtration and the filtrate was
concentrated and the residue was extracted with chloroform and
water. After drying the organic layer over anhyd Na2SO4 and con-
centration, the yellow residue was purified by column chroma-
tography (silica gel, chloroform) to obtain 78 (0.397 g, 0.609 mmol,
d
7.31 (s, 2H), 3.92 (s,12H).13CNMR(100 MHz,CDCl3):
d
166.66,152.83,
95.2%) as yellow oil. 1H NMR (400 MHz, CDCl3):
d 7.43 (d, 1H,
141.94, 125.07, 106.59, 60.87, 56.14, 52.20. IR (KBr) cmꢁ1: 3019.01,
2952.48, 2839.67, 1715.37, 1591.95, 1508.06, 1466.6, 1433.82, 1413.57,
1338.36, 1259.29, 1228.43, 1181.19, 1131.05, 993.16, 897.70, 864.92,
761.74, 736.67, 671.11, 440.66. Mp 85e86 ꢀC (lit. 85 ꢀC).10b
J¼4.0 Hz), 7.14 (d, 1H, J¼4.0 Hz), 7.06 (s, 2H), 4.07e3.99 (m, 6H),
1.85e1.71 (m, 6H),1.51e1.44 (m, 6H),1.39e1.22 (m, 24H), 0.93e0.85
(m, 9H). 13C NMR (100 MHz, CDCl3):
d 186.00,152.87,144.93,142.24,
134.42, 131.91, 130.97, 122.59, 107.82, 73.55, 69.20, 31.85, 31.77,
30.27, 29.46, 29.33, 29.30, 29.23, 26.01, 22.65, 22.63, 14.07. IR
(neat) cmꢁ1: 2926.45, 2855.10, 1738.51, 1637.27, 1578.45, 1499.38,
1466.60, 1426.10, 1337.39, 1225.54, 1114.65, 975.80, 856.24, 780.07,
747.28, 658.57. HRMS (TOF): calcd for C35H55BrO4SNa [MþNa]þ
673.290, found 673.260.
4.2.2. Synthesis of 3,4,5-trimethoxybenzoic acid (4).11 To a solution
of 3 (3.59 g, 15.9 mmol) in ethanol (120 ml) was added KOH (10.5 g,
0.187 mol) and refluxed for 48 h. After concentration, the residue was
extracted with chloroform and water. To the aqueous layer was
added 1 M HCl aq and the precipitate was extracted with chloroform.
After drying the organic layer over anhyd Na2SO4 and concentration,
the yellow residue was purified by column chromatography (silica
gel, chloroform) to obtain 4 (3.22 g, 15.2 mmol, 95.6%) as a white
4.2.6. 2-Bromo-5-(3,4,5-tridecyloxybenzoyl)thiophene (710). Yellow
oil, yield 84.6%. 1H NMR (400 MHz, CDCl3):
d
7.43 (d, 1H, J¼4.0 Hz),
7.13 (d, 1H, J¼4.0 Hz), 7.05 (s, 2H), 4.07e3.99 (m, 6H), 1.85e1.73 (m,
6H), 1.51e1.44 (m, 6H), 1.39e1.22 (m, 36H), 0.93e0.85 (m, 9H). 13
NMR (100 MHz, CDCl3): 186.00, 152.92, 144.98, 142.37, 134.41,
solid. 1H NMR (400 MHz, CDCl3):
d
7.39 (s, 2H), 3.94 (s, 9H). 13C NMR
171.71, 152.93, 142.85, 124.03, 107.28, 60.97,
C
(100 MHz, CDCl3):
d
d
56.21. IR (KBr) cmꢁ1: 2946.7, 2646.82, 1685.48, 1588.09, 1506.13,
1466.60, 1417.42, 1326.79, 1269.90, 1225.54, 1183.11, 1126.22, 1000.87,
939.16, 858.17, 761.74, 716.43, 548.65, 501.40, 459.94, 428.12. Mp
100e102 ꢀC (lit. 100e101 ꢀC) (lit. 99e101.5 ꢀC).11
131.95,130.98,122.59,107.94, 73.59, 69.29, 31.91, 31.89, 30.31, 29.71,
29.65, 29.60, 29.55, 29.37, 29.32, 29.27, 26.04, 22.67, 14.09. IR
(neat) cmꢁ1: 2920.66, 2850.27, 1617.98, 1577.49, 1502.28, 1467.56,
1427.07, 1412.60, 1383.68, 1339.32, 1226.51, 1120.44, 972.91, 852.38,
780.07, 741.50, 721.25, 609.40, 508.15, 470.55, 457.05, 441.62,
431.01, 407.87. HRMS (TOF): calcd for C41H67BrO4SNa [MþNa]þ
757.384, found 757.422.
4.2.3. Synthesis of 2-bromo-5-(3,4,5-trimethoxybenzoyl)thiophene
(5).12 Undernitrogen, SOCl2 (10 ml) was added to 4(3.10g,14.6mmol)
and refluxed for 4 h. After concentrating the reaction mixture, crude
3,4,5-trimethoxybenzoyl chloride was used to the next reaction.
Under nitrogen, AlCl3 (3.34 g,17.6 mmol) was added to a mixture
of the acid chloride and 2-bromothiophene (2.72 g, 16.7 mmol) in
4.2.7. 2-Bromo-5-(3,4,5-tridodecyloxybenzoyl)thiophene
(712). Yellow solid, yield 83.8%. 1H NMR (400 MHz, CDCl3):
d
7.43 (d,
1H, J¼4.0 Hz), 7.14 (d, 1H, J¼4.0 Hz), 7.05 (s, 2H), 4.06e3.99 (m, 6H),

T. Hirose et al. / Tetrahedron 70 (2014) 5100e5108
5107
1.85e1.72 (m, 6H), 1.48e1.43 (m, 6H), 1.39e1.22 (m, 48H),
0.93e0.85 (m, 9H). 13C NMR (100 MHz, CDCl3):
186.07, 152.91,
was washed with dichloromethane to give 10 (0.135 g, 0.368 mmol,
51.7%) as a yellow solid (The 1,8-isomer (0.156 g, 0.426 mmol,
65.5%) was obtained from the filtrate as a yellow solid.). 1H NMR
d
144.97, 142.27, 134.47, 131.95, 131.00, 122.65, 107.86, 73.60, 69.25,
31.92, 30.31, 29.73, 29.69, 29.65, 29.62, 29.56, 29.39, 29.37, 29.26,
26.05, 22.69, 14.13. IR (KBr) cmꢁ1: 2918.73, 2849.31, 2359.48,
1720.19, 1617.98, 1575.56, 1503.24, 1467.56, 1427.07, 1382.71,
1339.32, 1224.58, 1122.37, 969.06, 853.35, 781.03, 741.50, 583.36,
560.22, 490.80, 447.40, 431.01, 419.44. HRMS (TOF): calcd for
(400 MHz, CDCl3):
d
8.46 (d, 2H, J¼9.2 Hz), 8.11e7.97 (m, 6H), 1.80
(s, 12H). 13C NMR (100 MHz, CDCl3):
d
131.88, 130.97, 129.89, 128.03,
125.96, 124.95, 123.93, 117.73, 99.75, 81.04, 66.04, 31.70. IR
(KBr) cmꢁ1: 3334.32, 3042.16, 2979.48, 2934.16, 1598.70, 1493.60,
1459.85, 1436.71, 1415.49, 1379.82, 1279.54, 1200.47, 1159.97,
1004.73, 964.23, 905.42, 846.60, 793.56, 755.96, 719.32, 681.71,
538.04, 505.26, 462.83, 444.51, 419.44.
C
47H79BrO4SNa [MþNa]þ 841.477, found 841.527. Mp 49e50 ꢀC.
4.2.8. 2-Bromo-5-(3,4,5-tritetradecyloxybenzoyl)thiophene
(714). Yellow solid, yield 80.7%. 1H NMR (400 MHz, CDCl3):
7.43 (d,
d
4.2.13. Synthesis of 1,6-diethynylpyrenes (12).3d To a solution of 11
(0.270 g, 0.736 mmol) in dry toluene (30 ml) was added solid NaOH
(0.274 g, 6.85 mmol). After refluxing for 3 h, the reaction mixture
was filtered while hot. The filtrate was washed with water, dried
over anhyd Na2SO4, and concentrated to give 12 (0.182 g,
0.729 mmol, 99.0%) as a brown solid. 1H NMR (400 MHz, CDCl3):
1H, J¼4.0 Hz), 7.14 (d, 1H, J¼4.0 Hz), 7.05 (s, 2H), 4.06e3.99 (m, 6H),
1.85e1.72 (m, 6H),1.48e1.43 (m, 6H),1.39e1.19 (m, 60H), 0.92e0.83
(m, 9H). 13C NMR (100 MHz, CDCl3):
d 186.08, 152.91, 144.98,142.28,
134.48, 131.96, 131.01, 122.66, 107.86, 73.60, 69.26, 31.93, 30.32,
29.75, 29.71, 29.67, 29.63, 29.57, 29.40, 29.38, 29.27, 26.06, 22.70,
14.14. IR (KBr) cmꢁ1: 2919.70, 2848.35, 1617.98, 1574.59, 1504.20,
1467.56, 1427.07, 1383.68, 1339.32, 1260.25, 1225.54, 1123.33,
1064.51, 969.06, 854.31, 781.99, 741.50, 721.25, 666.29, 582.40,
529.36, 516.83, 487.90, 468.62, 432.94, 418.48. HRMS (TOF): calcd
for C53H91BrO4SNa [MþNa]þ 925.571, found 925.664. Mp 60e61 ꢀC.
d
8.58 (d, 2H, J¼9.2 Hz), 8.22e8.08 (m, 6H), 3.64 (s, 2H). 13C NMR
(100 MHz, CDCl3):
d 132.47, 131.33, 130.49, 128.24, 126.24, 125.07,
123.86, 117.24, 83.03, 82.51. IR (KBr) cmꢁ1: 3294.79, 3041.19,
2096.24, 1698.02, 1602.56, 1571.70, 1457.92, 1434.78, 1292.07,
1183.11, 1106.94, 843.70, 758.85, 716.43, 692.32, 644.11, 597.83,
549.61, 461.87, 417.51. HRMS (TOF): calcd for C20H11 [MþH]þ
251.086, found 251.099.
4.2.9. 2-Bromo-5-(3,4,5-trihexadecyloxybenzoyl)thiophene
(716). Yellow solid, yield 66.2%. 1H NMR (400 MHz, CDCl3):
d 7.43 (d,
1H, J¼4.0 Hz), 7.14 (d, 1H, J¼4.0 Hz), 7.05 (s, 2H), 4.06e3.99 (m, 6H),
4.2.14. Synthesis of 1,6-bis{2-[5-(3,4,5-trioctyloxybenzoyl)thienyl]
ethynyl}pyrene (18). Under nitrogen, 78 (0.560 g, 0.859 mmol) was
coupled with 12 (93.6 mg, 0.374 mmol) in the presence of
1.85e1.72 (m, 6H), 1.48e1.43 (m, 6H), 1.39e1.19 (m, 72H), 0.91e0.84
(m, 9H). 13C NMR (100 MHz, CDCl3):
d 186.07, 152.90, 144.97, 142.28,
134.47, 131.94, 130.99, 122.64, 107.86, 73.59, 69.25, 31.92, 30.31,
29.73, 29.71, 29.66, 29.63, 29.56, 29.37, 29.26, 26.05, 22.69, 14.13. IR
(KBr) cmꢁ1: 2917.77, 2848.35, 1735.62, 1617.98, 1577.49, 1504.20,
1467.56, 1427.07, 1339.32, 1228.43, 1124.30, 967.13, 852.38, 781.03,
741.50, 720.28, 607.47, 574.68, 498.51, 470.55, 456.08, 408.84. HRMS
PdCl2(PPh3)2 (26.3 mg, 37.4
mmol), dry Et2NH (20 ml), and CuI
(7.12 mg, 37.4
m
mol) in dry toluene (20 ml). After stirring at 50 ꢀC for
20 h, the reaction mixture was filtered through Celite. The filtrate
was concentrated and the orange residue was purified by thin layer
chromatography (silica gel, chloroform/hexane¼1:1) to obtain 18
(0.200 g, 0.144 mmol, 38.5%) as an orange solid. 1H NMR (400 MHz,
(TOF): calcd for
C
59H103BrO4SNa [MþNa]þ 1009.665, found
1009.779. Mp 65e66 ꢀC.
CDCl3):
d
8.59 (d, 2H, J¼9.2 Hz), 8.26e8.09 (m, 6H), 7.68 (d, 2H,
J¼4.0 Hz), 7.47 (d, 2H, J¼4.0 Hz), 7.14 (s, 4H), 4.12e3.90 (m, 12H),
1.91e1.72 (m, 12H), 1.55e1.42 (m, 12H), 1.42e1.10 (m, 48H),
4.2.10. 2-Bromo-5-(3,4,5-trioctadecyloxybenzoyl)thiophene
(718). Yellow solid, yield 72.1%. 1H NMR (400 MHz, CDCl3):
d
7.43 (d,
0.99e0.79 (m, 18H). 13C NMR (100 MHz, CDCl3):
d 186.51, 152.93,
1H, J¼4.0 Hz), 7.14 (d, 1H, J¼4.0 Hz), 7.05 (s, 2H), 4.06e3.99 (m, 6H),
144.10, 142.31, 134.27, 132.44, 132.02, 131.60, 131.32, 130.03, 128.49,
126.37, 125.50, 123.98, 117.41, 108.03, 96.00, 88.30, 73.64, 69.30,
31.91, 31.84, 30.35, 29.71, 29.53, 29.40, 29.38, 29.31, 26.09, 26.07,
22.71, 22.69, 14.13. IR (KBr) cmꢁ1: 2925.48, 2855.10, 2189.77,
1716.34, 1698.98, 1684.52, 1634.38, 1576.52, 1540.85, 1490.70,
1447.31, 1428.03, 1337.39, 1275.68, 1227.47, 1115.62, 841.78, 787.78,
744.39. HRMS (TOF): calcd for C90H119O8S2 1390.826; found:
1390.762 (Mþ, 61%), 1391.767 (100%), 1392.770 (72%), 1393.778
(31%), 1394.781 (9%), 1395.771 (2%).
1.85e1.72 (m, 6H), 1.48e1.43 (m, 6H), 1.39e1.19 (m, 84H), 0.91e0.83
(m, 9H). 13C NMR (100 MHz, CDCl3):
d 186.06, 152.91, 144.97, 142.29,
134.46, 131.95, 130.99, 122.64, 107.86, 73.59, 69.25, 31.92, 30.32,
29.72, 29.67, 29.64, 29.57, 29.37, 29.27, 26.06, 22.69, 14.13. IR
(KBr) cmꢁ1: 2916.81, 2848.35, 1617.02, 1576.52, 1504.20, 1467.56,
1427.07, 1383.68, 1339.32, 1225.54, 1126.22, 969.06, 852.38, 781.99,
741.50, 721.25, 458.01, 416.55. HRMS (TOF): calcd for
C
65H115BrO4SNa [MþNa]þ 1093.759, found 1093.919. Mp 77e78 ꢀC.
4.2.11. Synthesis of 1,6- and 1,8-dibromopyrenes (9, 10).14 According
to the literature,14 pyrene (2.00 g, 9.80 mmol) was reacted with Br2
(3.18 g, 19.9 mmol) in CCl4 (60 ml) at room temperature. The sus-
pension was filtered, and the remaining solid was dissolved in
chloroform and washed with Na2S2O3 aq. The organic layer was
dried over anhyd Na2SO4 and concentrated to give a white solid.
The composition can be determined by 1H NMR analysis, such as 9/
4.2.15. 1,6-Bis{2-[5-(3,4,5-tridecyloxybenzoyl)thienyl]ethynyl}pyrene
(110). Orange solid, yield 32.5%. 1H NMR (400 MHz, CDCl3):
d 8.62
(d, 2H, J¼9.2 Hz), 8.27e8.11 (m, 6H), 7.69 (d, 2H, J¼4.0 Hz), 7.47 (d,
2H, J¼4.0 Hz), 7.14 (s, 4H), 4.13e3.95 (m, 12H), 1.90e1.73 (m, 12H),
1.57e1.42 (m, 12H), 1.42e1.17 (m, 72H), 0.98e0.80 (m, 18H). 13C
NMR (100 MHz, CDCl3):
d 186.54, 152.93, 144.09, 142.31, 134.29,
132.44, 132.06, 131.64, 131.32, 130.07, 128.54, 126.41, 125.53, 124.04,
117.44, 108.03, 95.99, 88.31, 73.65, 69.31, 31.95, 31.92, 30.36, 29.76,
29.70, 29.66, 29.60, 29.43, 29.37, 29.32, 26.10, 22.71, 14.15. IR
(KBr) cmꢁ1: 2924.52, 2853.17, 2189.77, 1633.41, 1577.49, 1491.67,
1447.31, 1428.03, 1336.43, 1229.40, 1115.62, 840.81, 790.67, 745.35,
545.76. HRMS (TOF): calcd for C102H143O8S2 1559.014; found:
1558.999 (Mþ, 54%), 1559.992 (100%), 1560.989 (88%), 1562.019
(43%), 1563.016 (11%).
10¼1.1:1,
and
used
to the
next
reaction without
separation (Recrystallization of the mixture from chloroform
afforded a 9 enriched mixture (0.78 g, 9: 19.1%, 10: 2.8%).).
4.2.12. Synthesis of 1,6-bis(3-hydroxy-3-methylbuthynyl)pyrenes
(11).3d According to the literature,3d the mixture of 9 and 10 (1.1:1,
0.500 g) was reacted with 2-methyl-3-butyne-2-ol (0.252 g,
3.00 mmol) in the presence of PdCl2(PPh3)2 (97.6 mg, 0.139 mmol),
dry Et2NH (7 ml), and CuI (26.5 mg, 0.139 mmol) in dry toluene
(15 ml) at 50 ꢀC for 20 h. After filtration of the reaction mixture
through Celite, the filtrate was concentrated and the brown residue
4.2.16. 1,6-Bis{2-[5-(3,4,5-tridodecyloxybenzoyl)thienyl]ethynyl}pyr-
ene (112). Orange solid, yield 14.6%. 1H NMR (400 MHz, CDCl3):
d
8.61 (d, 2H, J¼9.2 Hz), 8.27e8.12 (m, 6H), 7.68 (d, 2H, J¼4.0 Hz),

5108
T. Hirose et al. / Tetrahedron 70 (2014) 5100e5108
7.46 (d, 2H, J¼4.0 Hz), 7.15 (s, 4H), 4.12e3.98 (m, 12H), 1.89e1.74 (m,
12H), 1.57e1.42 (m, 12H), 1.42e1.17 (m, 96H), 0.95e0.80 (m, 18H).
References and notes
13C NMR (100 MHz, CDCl3):
d 186.46, 152.95, 144.11, 142.41, 134.21,
1. (a) Handbook of Liquid Crystals; Demus, D., Goodby, J., Gray, G. W., Spiess, H.-W.,
Vill, V., Eds.; Wiley-VCH: Weinheim, Germany, 1998; Vols. 1e4; (b) Tschierske,
C. Chem. Soc. Rev. 2007, 36, 1930e1970; (c) Kato, T.; Mizoshita, N.; Kishimoto, K.
Angew. Chem., Int. Ed. 2006, 45, 38e68; (d) Gharbia, M.; Gharbi, A.; Nguyen, H.
132.44, 132.42, 132.07, 131.65, 131.29, 130.06, 128.52, 126.41, 125.51,
124.05, 117.46, 108.12, 95.96, 88.31, 73.64, 69.35, 31.94, 31.92, 30.36,
29.75, 29.70, 29.65, 29.59, 29.42, 29.40, 29.36, 29.33, 26.10, 22.69,
14.12. IR (KBr) cmꢁ1: 2923.56, 2853.17, 2357.55, 2189.77, 1732.73,
1631.48, 1577.49, 1492.63, 1447.31, 1428.03, 1336.43, 1276.65,
1228.43, 1118.51, 843.70, 788.74, 744.39, 508.15, 457.05, 430.05.
HRMS (TOF): calcd for C114H167O8S2 1727.202; found 1727.232 (Mþ,
26%), 1728.242 (93%), 1729.251 (100%), 1730.256 (57%), 1731.261
(19%), 1732.252 (3%).
^
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4.2.17. 1,6-Bis{2-[5-(3,4,5-tritetradecyloxybenzoyl)thienyl]ethynyl}
pyrene (114). Orange solid, yield 37.9%. 1H NMR (400 MHz, CDCl3):
d
8.61 (d, 2H, J¼9.2 Hz), 8.27e8.14 (m, 6H), 7.69 (d, 2H, J¼4.0 Hz),
7.47 (d, 2H, J¼4.0 Hz), 7.14 (s, 4H), 4.10e3.98 (m, 12H), 1.90e1.72 (m,
12H), 1.55e1.43 (m, 12H), 1.43e1.17 (m, 120H), 0.98e0.80 (m, 18H).
13C NMR (100 MHz, CDCl3):
d 186.49, 152.91, 144.07, 142.30, 134.25,
4. (a) Yasutake, M.; Fujiwara, T.; Nagasawa, A.; Moriya, K.; Hirose, T. Eur. J. Org.
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132.42, 132.04, 131.62, 131.29, 130.05, 128.51, 126.39, 125.50, 124.02,
117.43, 108.02, 95.97, 88.29, 73.62, 69.29, 31.92, 30.35, 29.76, 29.71,
29.65, 29.59, 29.42, 29.38, 29.30, 26.09, 22.69, 14.14. IR (KBr) cmꢁ1
:
€
2463e2466; (e) Hayer, A.; de Halleux, V.; Kohler, A.; El-Garoughy, A.; Meijer, E.
ꢁ
W.; Barbera, J.; Tant, J.; Levin, J.; Lehmann, M.; Gierschner, J.; Cornil, J.; Geerts,
2920.66, 2851.24, 2360.44, 1627.63, 1576.52, 1490.70, 1446.35,
1428.03, 1336.43, 1227.47, 1119.48, 841.78, 744.39, 720.28, 507.19,
471.51, 457.05, 431.01, 417.51. HRMS (TOF): calcd for C126H191O8S2
1895.390; found 1895.447 (Mþ, 23%), 1896.453 (86%), 1897.453
(100%), 1898.448 (56%), 1899.470 (15%), 1900.485 (3%).
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4.2.18. 1,6-Bis{2-[5-(3,4,5-trihexadecyloxybenzoyl)thienyl]ethynyl}
pyrene (116). Orange solid, yield 35.6%. 1H NMR (400 MHz, CDCl3):
d
8.64 (d, 2H, J¼9.2 Hz), 8.27e8.18 (m, 6H), 7.68 (d, 2H, J¼4.0 Hz),
7.47 (d, 2H, J¼4.0 Hz), 7.14 (s, 4H), 4.10e4.02 (m, 12H), 1.88e1.75 (m,
12H), 1.52e1.43 (m, 12H), 1.43e1.17 (m, 144H), 0.92e0.82 (m, 18H).
13C NMR (100 MHz, CDCl3):
d 186.48, 152.94, 144.11, 142.41, 134.22,
132.44, 132.42, 132.10, 131.68, 130.30, 130.09, 128.55, 126.44, 125.53,
124.09,117.49, 108.13, 95.96, 88.32, 73.64, 69.36, 31.92, 30.36, 29.75,
29.72, 29.66, 29.59, 29.42, 29.37, 29.33, 26.09, 22.69, 14.12. IR
(KBr) cmꢁ1: 2918.73, 2850.27, 2193.63, 1630.52, 1577.49, 1494.56,
1446.35, 1428.03, 1336.43, 1224.58, 1120.44, 841.78, 744.39, 720.28.
HRMS (TOF): calcd for C138H215O8S2 2063.577; found 2063.609 (Mþ,
14%), 2064.618 (78%), 2065.616 (100%), 2066.627 (67%), 2067.632
(23%), 2068.635 (5%), 2069.673 (1%).
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4.2.19. 1,6-Bis{2-[5-(3,4,5-trioctadecyloxybenzoyl)thienyl]ethynyl}
pyrene (118). Orange solid, yield 6.1%. 1H NMR (400 MHz, CDCl3):
d
8.64 (d, 2H, J¼9.2 Hz), 8.27e8.18 (m, 6H), 7.67 (d, 2H, J¼4.0 Hz),
11. Kreuchunas, A. J. Org. Chem. 1956, 21, 910.
7.46 (d, 2H, J¼4.0 Hz), 7.14 (s, 4H), 4.10e4.00 (m, 12H), 1.86e1.73 (m,
12H), 1.53e1.42 (m, 12H), 1.42e1.17 (m, 168H), 0.90e0.81 (m, 18H).
12. Yasuda, T.; Kishimoto, K.; Kato, T. Chem. Commun. 2006, 3399e3401.
€
ꢁ
13. Vlatta, I.; Harrison, I. T.; Tokes, L.; Fried, J. H.; Cross, A. J. Org. Chem. 1968, 33,
13C NMR (100 MHz, CDCl3):
d 186.44, 152.93, 144.10, 142.39, 134.19,
4176e4179.
14. Grimshaw, J.; Trocha-Grimshaw, J. J. Chem. Soc., Perkin Trans. 1 1972, 1622e1623.
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2002, 3, 532e535.
132.40, 132.08, 131.66, 131.27, 130.07, 128.53, 126.42, 125.51, 124.07,
117.47, 108.11, 95.93, 88.29, 73.62, 69.33, 31.90, 30.34, 29.73, 29.70,
29.64, 29.57, 29.40, 29.34, 29.31, 26.07, 22.67, 14.10. IR (KBr) cmꢁ1
:
2917.77, 2850.27, 1634.38, 1577.49, 1490.70, 1467.56, 1446.35,
1428.03, 1336.43, 1225.54, 1120.44, 842.74, 744.39, 720.28, 417.51.
HRMS (TOF): calcd for C150H239O8S2 2231.765; found 2231.828 (Mþ,
8%), 2232.822 (64%), 2233.835 (100%), 2234.833 (76%), 2235.841
(32%), 2236.816 (8%).
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Supplementary data
Supplementary data associated with this article can be found in
the online version, at http://dx.doi.org/10.1016/j.tet.2014.05.111.