Columnar liquid-crystalline imidazolium salts. effects of anions and cations on mesomorphic properties and ionic conductivities

Article abstract of DOI:10.1246/bcsj.80.1836

Two series of 1-methyl-3-[3,4,5-tris(alkyloxy)benzyl]imidazolium salts (1(n/X^-); n = 8, 12, 16, and 18) and 1,2-dimethyl-3-[3,4,5- tris(dodecyloxy)benzyl]imidazolium salts (2(12/X^-)) containing anions (X^-), such as tetrafluoroborate, hexafluorophosphate, trifluoromethylsulfonate, and bis(trifluoromethylsulfonyl)imide, have been synthesized. The thermal properties of these salts were characterized by differential scanning calorimetry, polarizing optical microscopy, and X-ray diffraction. The salts form hexagonal columnar liquid-crystalline phases except for 1(8/X^-) and 1(12/X^-) containing CF₃SO ₃^- and (CF₃SO₂)₂N ^-, and 2(12/(CF₃SO₂)₂N)^-) which melt directly to isotropic ionic liquids. The clearing points show a decreasing trend with an increase in the size of anions. The ionic conductivities of 1(16/X^-) forming columnar phases have been measured by using an alternating current impedance method. The conductivities depend on the nature of anions, suggesting that the predominant conduction mechanism is hopping and/or diffusion of anions in the columnar structures.

Full text of DOI:10.1246/bcsj.80.1836

1836 Bull. Chem. Soc. Jpn. Vol. 80, No. 9, 1836–1841 (2007)
ꢀ 2007 The Chemical Society of Japan
Columnar Liquid-Crystalline Imidazolium Salts. Effects of Anions
and Cations on Mesomorphic Properties and Ionic Conductivities
Masafumi Yoshio,1 Takahiro Ichikawa,1 Harutoki Shimura,1 Takayoshi Kagata,1
ꢀ1
Atsushi Hamasaki,2 Tomohiro Mukai,2 Hiroyuki Ohno,2 and Takashi Kato
1Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo,
Hongo, Bunkyo-ku, Tokyo 113-8656
2Department of Biotechnology, Tokyo University of Agriculture and Technology, Nakacho, Koganei, Tokyo 184-8588
Received December 28, 2006; E-mail: kato@chiral.t.u-tokyo.ac.jp
Two series of 1-methyl-3-[3,4,5-tris(alkyloxy)benzyl]imidazolium salts (1(n/Xꢁ); n ¼ 8, 12, 16, and 18) and 1,2-
dimethyl-3-[3,4,5-tris(dodecyloxy)benzyl]imidazolium salts (2(12/Xꢁ)) containing anions (Xꢁ), such as tetrafluoro-
borate, hexafluorophosphate, trifluoromethylsulfonate, and bis(trifluoromethylsulfonyl)imide, have been synthesized.
The thermal properties of these salts were characterized by differential scanning calorimetry, polarizing optical micros-
copy, and X-ray diffraction. The salts form hexagonal columnar liquid-crystalline phases except for 1(8/Xꢁ) and 1(12/
Xꢁ) containing CF3SO3ꢁ and (CF3SO2)2Nꢁ, and 2(12/(CF3SO2)2Nꢁ) which melt directly to isotropic ionic liquids. The
clearing points show a decreasing trend with an increase in the size of anions. The ionic conductivities of 1(16/Xꢁ)
forming columnar phases have been measured by using an alternating current impedance method. The conductivities
depend on the nature of anions, suggesting that the predominant conduction mechanism is hopping and/or diffusion
of anions in the columnar structures.
Liquid crystals are self-organized materials that form fluid
and ordered states.1 Liquid-crystalline (LC) nanostructures,
such as layer (smectic phase) and cylinder (columnar phase),
have the potential to be used as anisotropically functional
materials for charge, ion, and mass transportation.2 The self-
assembly of LC block molecules composed of two or more
covalently bonded immiscible molecular parts leads to the
formation of well-defined nano-segregated structures.3
Ionic liquids based on organic salts have attracted attention.4
It is of interest to introduce anisotropic self-assembled struc-
tures into ionic liquids for further functionalization. Recently,
we have reported on one-dimensional organic ion-conductors
Fig. 1. Fan-shaped imidazolium salts 1(n/Xꢁ) and 2(12/Xꢁ).
using columnar LC imidazolium salts.5 For example, 1-methyl-
3-[3,4,5-tris(alkyloxy)benzyl]imidazolium tetrafluoroborates
(1(n/BF4ꢁ)) (Fig. 1) show hexagonal columnar (Colh) LC
phases. The aligned columnar materials exhibit anisotropic
ionic conductivities. Although there had been several attempts
to obtain one-dimensional LC ion-conductors,6 no anisotropic
ion conduction and no macroscopic alignment had been
achieved until that time. The salts of 1(n/BF4ꢁ) have block
molecular structures consisting of ionic and non-ionic moie-
ties. The ionic moieties can self-assemble into the center of
the hexagonal columnar structure through ionic interactions
and nano-segregation behavior. These columns can be macro-
scopically aligned in two directions: parallel to the surface of a
glass substrate by mechanical shearing and vertical to the sur-
face of amine-functionalized substrates.5 However, the ionic
conductivities of the columnar imidazolium salts are about
10ꢁ7–10ꢁ4 S cmꢁ1 in the LC phases. If the conductivity can
be increased to the order of 10ꢁ3 S cmꢁ1, the applicability of
the columnar ionic materials as electrolytes will be increased.
In addition, improvement in the reduction stability of the imi-
dazolium ring to electrodes is also required for the develop-
ment of high-performance electrolytes.7
Our intention is to obtain columnar LC imidazolium salts
exhibiting both higher ionic conductivities and electrochemi-
cal stability through the chemical modification of the function-
al molecular structures. For normal ionic liquids that form
isotropic liquid states, the effects of cations and anions on their
properties were examined.8 The ionic conductivities of the
ionic liquids depend on the viscosities and the size of cations
and anions.8a MacFarlane and co-workers reported the ionic
conductivities of imidazolium salts depend on the cationic spe-
cies.8b It is of interest to examine the effect of the anions of LC
imidazolium salts on their ionic conductivities and self-ꢁassem-
bling properties. However, only the salts based on BF4 were
studied.5a,b In the case of the series of 1, the size of the imi-
dazolium cation is larger than those of normal imidazolium-
Published on the web September 13, 2007; doi:10.1246/bcsj.80.1836

M. Yoshio et al.
Bull. Chem. Soc. Jpn. Vol. 80, No. 9 (2007) 1837
Table 1. Thermal Properties of Compounds 1(n/Xꢁ) and 2(12/Xꢁ)
Compound
ꢁ
1st Coolinga)
2nd HeatingaÞ
bÞ
1(8/BF4
)
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
130 (1.0) Colh ꢁ37
G
G
ꢁ29
Colh 133 (1.0)
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
ꢁ
bÞ
cÞ
cÞ
1(12/BF4ꢁ
)
)
)
182 (1.1) Colh
175 (0.7) Colh
145 (1.2) Colh
8 (26) Cr
33 (72) Cr
60 (88) Cr
Cr 17 (29) Colh 183 (1.3)
Cr 74 (42) Colh 177 (1.5)
Cr 88 (87) Colh 148 (1.1)
1(16/BF4ꢁ
1(18/BF4
1(8/PF6
ꢁ
)
73 (0.6) Colh ꢁ38
Cr
G
ꢁ33
Colh
78 (0.6)
ꢁ
1(12/PF6ꢁ
1(16/PF6ꢁ
1(18/PF6
)
147 (1.0) Colh
167 (1.0) Colh
162 (1.1) Colh
—
73 (0.8) Colh
116 (0.9) Colh
115 (1.0) Colh
—
5 (26) Cr
48 (69) Cr
60 (92) Cr
Cr 12 (28) Colh 151 (1.0)
Cr 55 (63) Colh 167 (1.0)
Cr 68 (77) Colh 161 (1.2)
G0 ꢁ56 I0 ꢁ20 (25)dÞ Cr 1 (25)
)
)
ꢁ
1(8/CF3SO3
)
ꢁ72
G0
10 (39) Cr
52 (83) Cr
60 (90) Cr
ꢁ
1(12/CF3SO3ꢁ
1(16/CF3SO3ꢁ
1(18/CF3SO3
)
)
)
Cr 63 (57)
—
Cr 78 (90) Colh 117 (0.9)
Cr 86 (90) Colh 119 (1.0)
G0 ꢁ58 I0 ꢁ19 (31)dÞ Cr 2 (31)
1(8/(CF3SO2)2Nꢁ)
1(12/(CF3SO2)2Nꢁ)
1(16/(CF3SO2)2Nꢁ)
ꢁ70
G0
13 (34) Cr
52 (78) Cr
63 (85) Cr
10 (26) Cr
5 (23) Cr
13 (35) Cr
14 (82) Cr
—
Cr 37 (34)
—
55 (0.3) Colh
76 (0.7) Colh
177 (0.7) Colh
157 (0.9) Colh
83 (0.5) Colh
—
Cr 55 (78) Colh
Cr 66 (81) Colh
Cr 19 (27) Colh 174 (0.7)
Cr 58 (30) Colh 155 (0.8)
60 (0.2)
77 (0.7)
1(18/(CF3SO2)2Nꢁ)
ꢁ
2(12/BF4ꢁ
)
2(12/PF6
2(12/CF3SO3
)
ꢁ
)
Cr 66 (54) Colh
Cr 51 (77)
85 (0.6)
2(12/(CF3SO2)2Nꢁ)
—
a) Transition temperatures (ꢂC) and enthalpies of transition (kJ molꢁ1, in parentheses) determined by
DSC on the heating and cooling rates of 10 ꢂC minꢁ1. The transition temperatures were taken at the onset
points of the transition peaks. Cr: crystalline; Colh: hexagonal columnar; G, G0: glassy; I, I0: isotropic.
b) Ref. 5a. c) Ref. 5b. d) Cold crystallization.
Ionic conductivities were measured by using an alternating
current impedance method using a Schlumberger Solartron 1260
impedance analyzer (frequency range: 10 Hz–10 MHz, applied
voltage: 0.3 V) and a temperature controller. The samples of imi-
dazolium salts were heated up to the isotropization temperatures
in the glass measurement cell with comb-shaped gold electrodes
and then cooled to the temperature at which the columnar LC
phase is formed. The columnar materials were oriented by me-
chanical shearing in the directions parallel and perpendicular to
the applied electric field to measure ionic conductivities parallel
and perpendicular to the columnar axis, respectively.5 The heat-
ing rate of the measurements was fixed at 3 ꢂC minꢁ1. Ionic con-
ductivities were calibrated with a KCl aqueous solution (1.00
mmol Lꢁ1) as a standard conductive solution.
based ionic liquids. We expect the anionic species exert more
effects on the ionic conductivities of the series of the LC ma-
terials of 1 than normal ionic liquids. It is also of interest to
study the property–structure relationship of the imidazolium
salts as ionic LC materials.9,10
Here, we report on the mesomorphic properties and ionic
conductivities of 1-methyl-3-[3,4,5-tris(alkyloxy)benzyl]imi-
dazolium salts (1(n/Xꢁ)), n ¼ 8, 12, 16, and 18, Xꢁ = hexa-
fluorophosphate (PF6ꢁ), trifluoromethylsulfonate (CF3SO3ꢁ),
and bis(trifluoromethylsulfonyl)imide ((CF3SO2)2Nꢁ), and
1,2-dimethyl-3-[(3,4,5-tris(dodecyloxy)benzyl]imidazoliuꢁm
salts (2(12/Xꢁ)) including a tetrafluoroborate anion (BF4
)
(Fig. 1).
Experimental
Compounds 1(n/Xꢁ) and 2(12/Xꢁ) containing perfluorinated
anions were synthesized by a quaternization reaction of 1-methyl-
imidazole and 1,2-dimethylimidazole with 3,4,5-tris(alkyloxy)-
benzyl chloride, followed by anion exchange using silver
tetrafluoroborate, potassium hexafluorophosphate, silver triflate,
or lithium bis(trifluoromethylsulfonyl)imide in methanol (see
Supporting Information). These salts were purified by column
chromatography on silica gel (eluent: chloroform/methanol =
10/1). 1H NMR spectra were recorded using a JEOL JNM-LA400
at 400 MHz in CDCl3 relative to tetramethylsilane.
Thermal properties of the materials were examined by differen-
tial scanning calorimetry (DSC) using a Netzsch DSC204
Phoenixꢁ. The heating and cooling rates were 10 ꢂC minꢁ1. Tran-
sition temperatures were taken at the onset points of the transition
peaks. A polarizing optical microscope, Olympus BX51, equipped
with a Mettler FP82HT hot stage was used for visual observation.
X-ray diffraction measurements were carried out on a Rigaku
RINT 2500 diffractometer using a Cu Kꢀ radiation.
Results and Discussion
Liquid-Crystalline Properties. The thermal properties of
compounds 1(n/Xꢁ) and 2(12/Xꢁ) are presented in Table 1.
The phase-transition behavior of the series of 1(n/BF4ꢁ) was
reported in previous papers.5a,b These salts form enantiotropic
hexagonꢁal columnar LC phases except for the salts containing
CF3SO3 and (CF3SO2)2Nꢁ having octyl and dodecyl chains.
The series of compounds 1(n/BF4ꢁ) and 1(n/PF6ꢁ) exhibit
wider LC temperature ranges. Room-temperature columnar
LC phases are seen only for 1(n/BF4ꢁ) and 1(n/PF6ꢁ) having
octyl and dodecyl chains, and 2(12/BF4ꢁ). The highest tem-
perature of the columnar-isotropic transition is observed for
1(12/BF4ꢁ) at 183 ꢂC. For the series of 1(n/(CF3SO2)2Nꢁ),
the enantiotropic LC phases are induced by the introduction
of the hexadecyl and octadecyl chains. The melting points
show an increasing trend as the chain length increases.
Figure 2 shows a polarizing microscopic image of 1(16/

1838 Bull. Chem. Soc. Jpn. Vol. 80, No. 9 (2007)
Columnar Liquid-Crystalline Imidazolium Salts
Fig. 2. Polarizing optical micrograph of 1(16/(CF3SO2)2-
Nꢁ) in the Colh phase at 57 ꢂC.
Fig. 3. X-ray diffraction pattern of 1(18/(CF3SO2)2Nꢁ) in
the Colh phase at 74 ꢂC.
(CF3SO2)2Nꢁ) in the Colh phase at 57 ꢂC. The clearing points
show a decreasing trend with an increase in the size of anions.
For example, the clearing points of 1(16/Xꢁ) with BF4
,
ꢁ
PF6ꢁ, CF3SO3ꢁ, and (CF3SO2)2Nꢁ are 177, 167, 117, and
60 ꢂC, respectively. This suggests that the order of the staꢁbili-
zation effects oꢁn the columnar LC structures is BF4
>
PF6 > CF3SO3 > (CF3SO2)2Nꢁ. The bulky anions may
disturb their columnar packing. This trend in the fan-shaped
imidazolium salts is similar to that of 1-alkyl-3-methylimi-
dazolium salts9h showing smectic A phases, whereas no meso-
phases are formed for the salts with (CF3SO2)2Nꢁ. The vol-
ume fraction of ionic and non-ionic parts of the block mole-
cules and the strength of electrostatic interactions and hydro-
gen bonding are important for the formation of the LC phases.
As for the 2(12/Xꢁ), except for 2(12/(CF3SO2)2Nꢁ), the
Colh phase is formed despite the presence of a bulky methꢁyl
ꢁ
group on the imidazolium ring. Compound 2(12/CF3SO3
)
shows an enantiotropic Colh phase from 66 to 85 ꢂC, whereas
1(12/CF3SO3ꢁ) shows only a monotropic Colh phase from 73
to 10 ꢂC. The electron-donating substituent at the second posi-
tion of the imidazolium cation might stabilize the self-assem-
bled structures.
Fig. 4. Intercolumnar distanꢁces of the salꢁts 1(n/Xꢁ)
(CF3SO2)2Nꢁ ( ) in the Colh phases as a function of
the alkyl chain length of the imidazolium cation.
ꢁ
containing BF4 ( ), PF6
(
), CF3SO3
(
), and
X-ray Diffraction Study. X-ray diffraction patterns of
compounds 1(n/Xꢁ) and 2(12/Xꢁ) forming a columnar LC
phase show three reflections with the reciprocal spacing ratio
position may not contribute to the increase of the size of
ꢁ
pffiffiffi
of 1: 3:2 in a small-angle region and a broad halo at 2ꢁ ¼
20ꢂ due to disordered aliphatic chains. For example, 1(18/
(CF3SO2)2Nꢁ) shows the reflections with d-spacing values
columns. The CF3SO3 is relatively bulky, and its negative
charge is stabilized by delocalization in the anion structure.
Therefore, hydrogen bonding and Coulombic interactions with
the imidazolium cations should be weaker. In contrast, the
BF4ꢁ and PF6ꢁ are spherical and should form stronger interac-
tions with the imidazolium cations in all directions in the cen-
˚
of 37.7, 21.8, and 18.9 A, as shown in Fig. 3. These results in-
dicate that a hexagonal columnar structure is formed. The in-
tercolumnar distances (a) of these salts were calculated with
pffiffiffi
ꢁ
ꢁ
the equation of a ¼ 2d100
=
3, where the values of d100 were
ter of the columns. Thus, the BF4 and PF6 may form inner
ionic columnar structures with cations, resulting in larger inter-
columnar distances than that of CF3SO3ꢁ. As for the 2(12/
obtained from the diffraction of the columnar phases at 10 de-
grees below the isotropization temperatures, except for 1(n/
(CF3SO2)2Nꢁ). The results for 1(n/Xꢁ) are summarized in
Fig. 4. With an increase in the alkyl chain length, the distance
between columns increases, except for 1(18/Xꢁ). A correla-
tion between the anions and the intercolumnar distance is
not clear, although the distance is expected to inꢁcrease asꢁthe
ꢁ
˚
X ), the intercolumnar distances is 38.3 A. The introduction
of the methyl group on the imidazolium ring does not disturb
the hexagonal columnar packing.
Alignment of Columns and Ion-Conductive Properties.
The LCꢁcolumns of 1(16/Xꢁ) containing BF4ꢁ, PF6ꢁ, and
CF3SO3 were aligned macroscopically perpendicular and
parallel to the comb-shaped gold electrodes by mechanical
shearing (Fig. 5). This alignment technique for columnar LC
imidazolium salts were described in previous papers.5 The
formation of columnar monodomains for 1(16/Xꢁ) has been
confirmed with polarizing optical microscope observation.
size of anions increases in the order of BF4 < PF6
<
CF3SO3 < (CF3SO2)2Nꢁ. The columnar distances for 1(nꢁ/
CF3SO3ꢁ) are rather shorter than those for the salts with BF4ꢁ
and PF6ꢁ. It can be attributed to the intrusion of CF3SO3
into the lipophilic alkyloxypheny region due to its weaker
Coulombic interactions with the imidazolium cations. This
ꢁ

M. Yoshio et al.
Bull. Chem. Soc. Jpn. Vol. 80, No. 9 (2007) 1839
Fig. 5. Polarizing optical microscopic images and schematic illustration of the self-assembled structures of 1(16/CF3SO3ꢁ) in the
Colh phase at 100 ꢂC: (a) before shearing; after shearing the material along the direction, (b) parallel, and (c) perpendicular to the
electric field. Directions of A: analyzer; P: polarizer; S: shearing. (d) Illustration of a glass cell with comb-shaped gold electrodes
for the anisotropic ion conduction measurements. Sample thickness: 0.8 mm.
The ionic conductivities were measured for 1(16/Xꢁ) with
columnar orientation parallel to the surface of the glass sub-
strate. Figure 6 shows the ionic conductivities parallel (ꢂ )
k
and perpendicular (ꢂ ) to the columnar axis for these 1(16/
?
Xꢁ) as a function of temperature. Anisotropic conductivities
are observed for 1(16/Xꢁ) in the columnar phases. The values
of ꢂ are higher than those of ꢂ . For example, 1(16/
k
?
CF3SO3ꢁ) shows the conductivities of 1:3 ꢃ 10ꢁ5 S cmꢁ1
(ꢂ ) and 6:5 ꢃ 10ꢁ7 S cmꢁ1 (ꢂ ) at 100 ꢂC. No anisotropy is
k
?
observed when the materials form isotropic liquid phases.
For example, the anisotropy for 1(16/CF3SO3ꢁ) disappears
at 117 ꢂC. These results indicate that ion-conducting paths
are formed along the columnar axis in the Colh phases and
the alkyloxyphenyl part functions as an ion-insulating part.
As for 1(16/BF4ꢁ) and 1(16/PF6ꢁ), anisotropy is observed
until temperatures that are 10–15 degrees above the onset
points of the columnar-isotropic transitions because these com-
pounds show broader isotropization temperature ranges.
The ꢂ values for 1(16/PF6ꢁ) are higher than those for
k
1(16/BF4ꢁ) from 85 to 150 ꢂC. The ionic conductivities (ꢂ )
k
for 1(16/CF3SO3ꢁ) are almost the same as those of 1(16/
ꢁ
BF4ꢁ) below 100 ꢂC, while the ꢂ values for 1(16/CF3SO3
)
k
are lower than those for 1(16/BF4ꢁ) above 100 ꢂC. The ꢂ
ꢁ
Fig. 6. Anisotropic ionic conductivities of 1(16/BF4
)
k
values for 1(16/Xꢁ) in the Colh phases at 110 ꢂC increase in
(ꢂ : , ꢂ : ), 1(16/PF6ꢁ) (ꢂ : , ꢂ : ), and 1(16/
k
?
k
?
the order of PF6 > BF4 > CF3SO3ꢁ. The anisotropy of
CF3SO3ꢁ) (ꢂ : , ꢂ : ) as a function of temperature.
k ?
ꢁ
ꢁ

1840 Bull. Chem. Soc. Jpn. Vol. 80, No. 9 (2007)
ionic conductivities (ꢂ =ꢂ ) decreases with an increase in the
Columnar Liquid-Crystalline Imidazolium Salts
Weinheim, 1998.
a) N. Boden, R. J. Bushby, J. Clements, B. Movaghar,
J. Mater. Chem. 1999, 9, 2081. b) D. Adam, P. Schuhmacher, J.
k
?
2
size of the anions. For example, the values of anisotropy ob-
tained for 1(16/BF4ꢁ), 1(16/PF6ꢁ), and 1(16/CF3SO3ꢁ) in
the Colh phases at 110 ꢂC are 1:1 ꢃ 102, 8:1 ꢃ 10, and 1:5 ꢃ
10, respectively. For 1(16/(CF3SO2)2Nꢁ), only ionic conduc-
tivities of the polydomain sample were measured because the
formation of a columnar monodomain was difficult due to the
narrow temperature range of the Colh phase (from 55 to 60 ꢂC).
Compound 1(16/(CF3SO2)2Nꢁ) shows the conductivities of
4:7 ꢃ 10ꢁ6 S cmꢁ1 in the Colh phase, forming polydomain at
59 ꢂC, and 3:6 ꢃ 10ꢁ5 S cmꢁ1 in the isotropic phase at 110 ꢂC.
As for 1(16/Xꢁ), the cationic imidazolium moiety is con-
sidered to be less mobile than the anions in the columnar struc-
ture. The observed ionic conductivities may be mostly due to
the diffusion and/or hopping of the anions inside the columns
because the conductivities strongly depend on the anions. In
future, we will examine the mechanism of ion conduction in
the columnar LC phases using NMR measurements.11
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Conclusion
The anions of columnar LC 1-methyl-3-[3,4,5-tris(alkyl-
oxy)benzyl]imidazolium salts (1(n/Xꢁ)) exert significant ef-
fects on the mesomorphic properties and ionic conductivities.
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ꢁ
CF3SO3 and (CF3SO2)2Nꢁ. It is noteworthy that the meso-
ꢁ
phases displayed by the salts 1(12/Xꢁ) containing BF4 and
ꢁ
PF6 are stable over 150 ꢂC. Columnar LC phases are ob-
served for the salts 1(16/Xꢁ) and 1(18/Xꢁ) containing
CF3SO3 and (CF3SO2)2Nꢁ. As for 1,2-dimethyl-3-[3,4,5-
ꢁ
tris(dodecyloxy)benzyl]imidazolium salts (2(12/Xꢁ)) contain-
ing BF4ꢁ, PF6ꢁ, and CF3SO3ꢁ, columnar LC phases are
formed despite the presence of a bulky methyl group on the
imidazolium ring. Anisotropic ionic conductivities are ob-
served for the 1(16/Xꢁ) containing BF4ꢁ, PF6ꢁ, and CF3SO3
ꢁ
in the Colh phases, in which the columns of these salts are
macroscopically aligned by mechanical shearing. The ionic
conductivities parallel to the columnar axis are higher than
those perpendicular to the columnar axis.
4
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This study was partially supported by Grant-in-Aid for
Scientific Research on Priority Areas of ‘‘Science of Ionic
Liquids’’ (No. 18045010) (T.K.), Creative Scientific Research
of ‘‘Invention of Conjugated Electronic Structures and Novel
Functions’’ (No. 16GS0209) (T.K.), and Grant-in-Aid for
Scientific Research (B) (No. 17350065) (T.K.) from the
Japan Society for the Promotion of Science (JSPS) and
Grant-in-Aid for The 21st Century COE Program for Frontiers
in Fundamental Chemistry (T.K.) from the Ministry of
Education, Culture, Sports, Science and Technology.
Supporting Information
Synthesis of 1(18/Xꢁ) and 2(12/Xꢁ). This material is available
free of charge on the web at http://www.csj.jp/journals/bcsj/.
5
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