Bolaamphiphilic liquid crystals based on bis-imidazolium cations

Article abstract of DOI:10.1039/c6nj03590f

Syntheses are reported for new bolaform ionic liquids 2a-f containing the cyanometallate anions [Ag(CN)₂]^? (2a), [Ni(CN)₄]^2? (2b), [Pt(CN)₄]^2? (2c), [Co(CN)₆]^3? (2d), [Fe(CN)₆]^3? (2e) and [Fe(CN)₆]^4? (2f), respectively, associated with a bis(imidazolium) dication. Except for those containing the square-planar nickelate and platinite anions, all the compounds displayed thermotropic behaviour, exhibiting lamellar smectic A phases. The mesomorphic behavior and phase transition temperatures were investigated by polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and small-angle X-ray scattering (SAXS). To investigate the nature anion influence on its interactions with the cation, crystal structures from single crystal X-ray diffraction have been obtained for both [Ag(CN)₂]^? and [Ni(CN)₄]^2? derivatives. These studies showed that the square planar Ni anion disrupts the lateral cohesion of the ionic layers. This may explain the loss of liquid crystal behavior in this case and Pt salt.

Full text of DOI:10.1039/c6nj03590f

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ISSN 1144-0546
PAPER
Jason B. Benedict et al.
The role of atropisomers on the photo-reactivity and fatigue of
diarylethene-based metal–organic frameworks
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Bolaamphiphilic Liquid Crystals Based on Bis-imidazolium Cations.
Alexandre Al Abbas,a Benoît Heinrich,a Matthieu L’Her,a Emilie Couzigné,a Richard Welterb and
Laurent Douce a†
Received 00th January 20xx,
Accepted 00th January 20xx
Syntheses are reported for new bolaform ionic liquids 2a-f containing the cyanometallate anions [Ag(CN)2]- (2a), [Ni(CN)4]2-
(2b), [Pt(CN)4]2- (2c), [Co(CN)6]3- (2d), [Fe(CN)6]3- (2e) and [Fe(CN)6]4- (2f), respectively, associated with a bis(imidazolium)
dication. Except for those containing the square-planar nickelate and platinite anions, all the compounds displayed
DOI: 10.1039/x0xx00000x
www.rsc.org/
thermotropic behaviour, exhibiting lamellar smectic
A phases. The mesomorphic behavior and phase transition
temperatures were investigated by polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and small-
angle X-ray scattering (SAXS). To investigate the nature anion influence on its interactions with the cation, crystal
structures from single crystal X-Ray diffraction have been obtained for both [Ag(CN)2]- and [Ni(CN)4]2- derivatives. These
studies showed that the square planar Ni anion disrupts the lateral cohesion of the ionic layers. This may explain the loss
of liquid crystal behavior in this case and Pt salt.
and/or the solvent (lyotropic liquid crystals). In the case of
thermotropic liquid crystals the organizations give rise to
nematic phases (molecules are aligned along a particular axis),
Introduction
Over the past decade, extensive studies of ionic liquids (ILs)
have revealed their many useful properties such as extremely
low volatility, high thermal stability, non-flammability, high
chemical and radiochemical stability, high ionic conductivity
and wide electrochemical window.1-3 These have led to their
use, for example, as new reaction media, increasing the yields
of many syntheses and eliminating the hazards associated with
some conventional solvents.4 Changes in both the cation and
its counter anion can be used to fine-tune properties such as
smectic phases (orientational /positional order with formation
of layers) and columnar phases (orientational/positional order
with formation of columns arranged in a two-dimensional
lattice). The lyotropic compounds display not only lamellar and
columnar organization but also hierarchical self-assembly into
spheres (micelles), ribbons and fibres. These unique properties
have led to applications ranging from display technology
through templating media for synthesis to biological activity
(targeting and transportation of drugs and gene materials).11
The vast majority of liquid crystal molecules are made up of a
rigid part functionalized by alkyl tails. For example, the
mesomorphic molecules known as liquid crystal oligomers
(particularly dimers) has been widely studied as model
compounds for the technologically important semi-flexible
main chain liquid crystal polymers. Here, the molecular
structure is formed by linking standard mesogenic components
with flexible alkyl chains.12
viscosity,
hydrophilicity/hydrophobicity.1
melting
point,
polarity
Important
and
emerging
applications include those in separation and extraction
processes, in catalysis and in various electrochemical devices,2,
5,
6
9
such as lithium ion batteries,7 solar cells,8, as well as
capacitors.2
Liquid crystals are characterized by both mobility and self-
organization at the macroscopic level.10 Almost all such
mesomorphic materials are based on molecules combining
two antagonistic units consisting of rigid (aromatic) and
flexible (alkyl) or hydrophilic (polar heads) and hydrophobic
(alkyl chains) parts. The subtle balance of these effects governs
the formation of a multitude of supramolecular architectures
depending on the temperature (thermotropic liquid crystals)
Full convergence of the ionic liquid and liquid crystal fields
could provide a vast range of materials (Ionic liquid crystals,
ILCs) with novel and tuneable characteristics such as those of
ordered and oriented hybrid compound semiconductors
exhibiting both electronic and ionic conductivity.13-15 In that
matter, the imidazolium unit is an excellent platform that can
be designed to promote liquid crystalline phases and easily
varied with a large diversity of anions.16-19
Despite growing interest in ionic liquids properties based on
imidazolium compounds, very little is known about
bolaamphiphile species, which may form liquid crystals. Ionic
liquid crystal dimers (bolaform) will be defined as consisting of
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molecules composed by charged semi-rigid mesogenic units
connected via flexible spacers (Scheme 1). In contrast, the equivalents of M(CN)xn-, RT, 10 days.
Gemini form with lateral alkyl tails starts to be well reported.20-
28
For such multiply-charged species, the charge on the
Journal Name
Scheme 3: Precipitation of 2a-f from water/methanol in presence of
2
In order to investigate the influence of the form and charge of
the counteranion, dication derivatives with [Ag(CN)2]- (2a),
[Ni(CN)4]2-
(
2b), [Pt(CN)4]2-
(
2c), [Co(CN)6]3-
(
2d), [Fe(CN)6]3-
(
2e)
counterion plays a crucial role in inducing specific properties or
non-covalent reticulation of the materials (Scheme 1).
and [Fe(CN)6]4-
(
2f) were synthesized. All were obtained in
excellent yield by mixing the dication bromide in a methanolic
solution with an aqueous solution of the cyanometallate
potassium salt respectively. The very water-insoluble
precipitates were simply washed well with water and then
dried in vacuum to obtain the pure materials. All these
compounds were fully characterized by the by standard
methods (NMR, FT-IR, UV and elemental analysis). The IR
Scheme 1: ionic bolaamphiphile schematic representation based on imidazolium
“dimer”.
spectra show typical anion vibrations of νCN = 2127 cm-1
2119 cm-1 2b), 2124 cm-1 2c), 2134 cm-1 2d), 2106 cm-1
and 2044 cm-1
2f). The UV spectrum displays in MeOH for all
the compounds two typical transitions charge transfer (n-π*
and π-π*) at 230 ( > 5000
> 10 000 M-1. cm-1) and 270 nm (
(
2a),
2e
(
(
(
(
)
(
Results and discussion
Synthesis and characterisation
ε
ε
M-1. cm-1) generated by the aromatic parts. Moreover, it’s
difficult to determine d-d transition due to the poor solubility
of such complexes. However, we succeeded to measure with a
Herein, we report the synthesis of a bolaform bis(imidazolium)
species (Scheme 2) designed to give liquid crystal behavior and
to facilitate study of the influence of the counteranion on the
poor precision for the Fe(II) 2e (420 nm,
Fe(III) 2f (425 nm,
≈ 55 M-1. cm-1) . The chemical shift for the
ε
≈ 85 M-1. cm-1) and
mesomorphism. Compound
1,
1,1'-(4,4'-(dodecane-1,12-
ε
proton CH (1H-imidazolium) is very dependent upon the anion,
diylbis(oxy))bis(4,1-phenylene)) bis(methylene)bis(3-methyl-
1H-imidazol-3-ium) bromide was prepared in a three-step
procedure in 72 % yield overall
being found at δ = 8.92 ppm (2a), 9.12 ppm (2d) and 7.94 ppm
(
2e). For the compounds 2b
observed due to proton/deuteron exchange with the
solvent.29, 30 Thermogravimetric analysis of compounds
and
, 2c, 2f, this signal was not
1
2a-f showed them to be stable up to 200°C (see scheme 3).
Below 100°C, weight loss consistent with dehydration was
observed. Hydration was confirmed by elemental analyses and
thus the compounds must be regarded as deliquescent.
Scheme 2: Synthesis of the bromide 1. Reaction conditions: (i) DMF, K2CO3, 100
°C, overnight ; (ii) LiAlH4, THF, 4 h ; (iii) SOBr2, DCM; dry THF, two equivalents of
methylimidazole under an inert atmosphere.
The bromide salt
1 is air stable and was purified by flash
chromatography (gradient 100/0 to 95/5: CH2Cl2/MeOH).
Distinctive signals of the CH (1H-imidazolium) group appear in
1
the H and 13C NMR spectra at 9.06 ppm and at 137.67 ppm,
respectively.
Scheme 4: TGA curves of the dry Bis(imidazolium) salts, after the first heating to
100°C for drying. Weight losses related to decomposition starts from 200-230°C
and the 5 % weight loss temperatures are around 235°C (2e: Fe[CN]63-), 2453°-C (
2:
-
Br-; 2f: Fe[CN]64-), 260°C (2a: Ag[CN]2 ; 2b: Ni[CN]42-) and 275°C (2d: Co[CN]6
; 2c:
Pt[CN]42-); ramp: 5°C/Min; gas: air.
Single-Crystal X-ray Diffraction Studies
Single crystals of 2a and 2b suitable for X-ray diffraction
measurements were obtained by slow diffusion of an aqueous
cyanometallate solution into a solution of
1 in methanol. The
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stoichiometric unit found in the lattice of 2a is shown in Figure
1 and a partial view of the lattice is given in Figure 2.
Figure 3: ORTEP view, with partial labeling, of the asymmetric unit of 2b
showing the imidazolium-CH/N-cyano bonds (see also the inset) and CH-
,
π
interactions (arrows and/or dashed lines). Symmetry codes for equivalent
positions : ‘ : 1-x,-1-y,1-z ; ‘’ 2-x,-2-y,1-z.
Figure 1: ORTEP view, with partial labeling, of the asymmetric unit of 2a showing
both types of weak CH interactions. The CH-π interactions are represented as
contacts to the centroid of the phenyl ring. The displacement probability
ellipsoids are shown at the 50 % level. Symmetry codes for equivalent positions: ‘
: x, y-1, z ; ’’ : 1+x, 1+y, z. Imidazolium-CH/N-cyano hydrogen bond C4_H4…N3’’ :
0.9498 Å ; 2.2856 Å ; 3.182(4) Å; 157°. CH-
π interaction: centroid of C6_C11
phenyl ring and H13’ : 2.9821 Å ; 167 ° ; 3.954(3) Å.
The solid array is formed by ionic double layers containing the
imidazolium dimer and argentate species separated by
strongly tilted (65.5°) (CH2)12 spacers. This arrangement is
supported by two types of CH interactions: 1) imidazolium-CH
with the counter anion and 2) CH-π interactions between the
phenyl ring and the CH2 in beta-position in the chains.
Figure 4: Complex 2b lattice partial view. The arrow point to the main intermolecular
CH-π interactions.
Contacts consistent with the different H-bonding interactions
are gathered in Tables 1 and 2.
Donor
H
Acceptor_code
D-H
H…A
D…A
D - H…A
O3
O3
C2
H1
N7_$1
N8
0.79(4)
0.90(4)
0.9493
0.9500
0.9896
0.9498
0.9798
2.18(4)
1.99(4)
2.4370
2.5651
2.5053
2.5326
2.4187
2.966(3)
2.850(3)
3.085(3)
3.497(3)
3.484(2)
3.363(3)
3.385(4)
173(4)
159(3)
125.32
166.84
170.04
146.08
168.69
H5
H2
O3_$2
N7_$3
N6_$3
N8_$4
O3_$4
C3
H4
C5
H5B
H32
H34B
C32
C34
Table 1: H-bonding contacts in the complex 2b lattice. Symmetry codes for
equivalent positions: $1 = 1-x,-1-y,-z; $2 = -x,-y,-z; $3 = -1+x,1+y,z; $4 = 3-x,-1-
y,1-z.
X--H
CX_CY_ring_code
C9_C11_$1
H…Cg
X-H..Cg
145.24
143.61
X…Cg
C23--H23A
C16--H16B
2.7954
2.8697
3.6519(19)
3.7129(18)
C24_C29_$5
Table 2: Shortest X-H...Cg(π-Ring) contacts in the complex 2b lattice. Symmetry
codes for equivalent positions: $1 = 1-x,-1-y,1-z; $5 = 2-x,-2-y,1-z.
Mesomorphic properties.
Figure 2: Complex 2a packing diagram in the (a,c) plane projection
For all the compounds, the mesomorphic behavior and phase
transition temperatures were investigated by polarizing optical
microscopy (POM), differential scanning calorimetry (DSC) and
small-angle X-ray scattering (SAXS). To avoid possible effects of
the material hydration, all were dried under vacuum at 50°C
overnight before measurements. The phase transition and the
corresponding enthalpy changes derived for the compounds
are compiled in Table 3.
Unlike that of 2a, the ionic double layer of 2b contains water
molecules involved in the CH bond networks. As well, the
tilting of the spacers is slightly smaller (62.3°) than in the
crystal of 2a. CH-π interactions with the aromatic units occur
again but involve methylene groups in the and positions of
the spacer chains.
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c
Transitionsa
T(°C)b
ΔH (kJ.mol-1
)
and the extended aliphatic chains. At higher temperatures in
the mesophase, the molecular area decreases again and
continuously up to the isotropization. Since the thermal
expansion and softening of the aliphatic tails sets the
compromise molecular area to a lower ruffling degree of the
ionic layers. Remarkably, the evolution of the smectic A
polymorphism in the salt series follows mainly the counter-ion
size variation: the mesophase exists in a similar molecular area
range throughout the series, but the molecular area close to
the isotropization is reached earlier in the case of bigger
counter-ions.
Ref.
Anion
Cr ꢀ
A
82
127
78
44
1.8
12
2
Br-
SmA ꢀ Iso
Cr ꢀ SmA
-
2a
2b
2c
2d
2e
2f
Ag(CN)2
SmA ꢀ Iso
Cr1 ꢀ Cr2
Cr2 ꢀ Iso
124
98
1.2
7
2-
2-
3-
Ni(CN)4
Pt(CN)4
147
33
Cr ꢀ Iso
149
91
50
28
Cr ꢀ SmA
Co(CN)6
SmA ꢀ d
Cr ꢀ SmA
SmA ꢀ d
Cr ꢀ SmA
>230
91
The bolaamphiphiles cationic moiety, investigated here, is
considered as a dimer formed by connecting the tails of these
previously studied compounds, called "monomers" hereafter.
Another variation concerns the anions: besides the singly-
12
36
3-
Fe(CN)6
Fe(CN)6
>210
68
4-
SmA ꢀ d
>220
charged, spherical bromide and the singly-charged linear
-
Table 3: Phase transition temprature (T) and corresponding enthalpies (DH)
determined from the 1st heating cycle. – Abbreviations: Cr ), Cr1 ), Cr2 )
a
shaped Ag[CN]2
(
2a), the bolaamphiphiles series includes also
crystalline phases; SmA ) smectic phase; Iso ) isotropic liquid phase; d)
A
b
multi-charged cyanometallates of different geometries. All
compounds exhibiting smectic A ranges were characterized by
SAXS. The molecular volume variation of the dimer bromide
was directly measured by dilatometry and used to calculate
the volume variations of the other terms of the series as
described previously.33 Molecular areas in the mesophase
were finally obtained from the ratio of these molecular
volumes and of the layer spacings and compared to the values
in the crystalline state from single-crystal structures (see
previous section).
decomposition. All the transition temperatures listed in this table. Correspond
1 mole
to peak maximums in heating run DSC traces.c Calculated for
Bis(imidazolium) units and stoichiometric amount of counter-ions.
Only the compounds containing tetracyano-nickelate and -
platinite anions do not show thermotropic behavior. The
optical textures observed by POM for
1 during slow cooling
from isotropic melts displayed the emergence of typical
smectic A phase. The mesophase appears as Batônnet rods
(figure 5 left) and turn into a wide fan like focal-conic texture
(figure 5 right).
One may expect that the bonding of the tails in the aliphatic
layers stabilizes the layering and reduces the fluidity, shifting
melting and isotropization temperatures upward, as found for
other systems.35, 36 However, comparison of the polymorphism
(see Figure
6
and ref.)33 indicates that the transition
temperature shift is small or nonexistent here (a more precise
answer is not possible, since the polymorphism is strongly
chain length dependent and the monomer bromide series
starts with octyl tails, i.e. still more than the half dimer spacer
length corresponding to hexyl). Moreover, mesophase
molecular areas (see Figure 7) do not differ significantly
between dimer and monomer (this comparison is more
reliable because the chain length dependence is very weak, as
found for the monomer bromide series).33 Molecular areas are
Figure 5: (left) Smetic A phase emergence from the isotropic liquid at 124°C.
(right) Typical Smetic A phase texture at 110°C.
A diffuse band at 4.6 Å (wide angle) found in compound 1, X-
ray pattern recorded at 110°C shows clearly that the alkyl
spacers have liquid-like structure (Figure 6). The layer
thickness in the smectic A phase was determined from the
position of the sharp reflection in the small angle region
-
also similar in crystalline phases, as shown for Ag[CN]2 dimer
(1 d = 28.5 Å at 110 °C).
(2a) and monomer (43.6 and 46.7 Å2, respectively). Actually,
essential identity in the crystalline phase was expected, since
the molecular area is then determined by the flat ionic layers
and thus the natural size of ionic species. The apparent
identity in the mesophase is more surprising and means that
the degree of ruffling of the ionic layers is not significantly
modified between monomers and dimers. Since this degree of
ruffling is directly related to the degree of folding of the
aliphatic chains and it is perhaps surprising that these
characteristics of the packing are not significantly influenced
by the chain ends buried in the aliphatic layer.
Monocatenary liquid crystals series containing methyl-
imidazolium with bromide and other singly-charged counter-
ions have been previously investigated.31-33 The polymorphism
evolution in the series could be well described by using the
molecular area, obtained as the ratio of the molecular volume
measured by dilatometry to the layer spacing obtained from
SAXS patterns. In agreement with single-crystal X-ray
diffraction for another monocatenar analogue,34 the molecular
area in the crystalline phase is determined by the flat ionic
double layer and is more than twice that of the strongly tilted
aliphatic tails. Melting to the smectic A phase causes ruffling
of the ionic layers and the molecular area drastically increases
to an intermediate value between the flat of ionic layer lattice
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Figure 6: (Left) DSC runs of liquid-crystalline Bis(imidazolium salts (ramps of 5°C/Min, endotherm up); Cr: crystalline phase; SmA: smectic A phase; Iso: isotropic liquid
phase. Both monovalent anion salts (2: Br-; 2a: Ag[CN]2-) show similar melting and isotropization temperature, i.e of ca. 80°C and 125°C, whereas hexacyano-
metalate salts SmA phases stay up to degradation above 200°C. Behaviors are also different on cooling: crystallization occurs for the former salts and supercooling of
the SmA phase for the latter.
(Center and Right) SAXS patterns in the SmA phase at 100°C, only displaying the first order reflection (001) of the lamellar periodicity and a broad wide-angle
scattering signal from overlapping lateral distances betwee molten chains (hch) and mesogenic moieties (hmes). The low-quality patterns obtained for Co and Fe-
containing samples are due to absorption of CuKα1 radiation and fluorescence emission.
In marked contrast with this low influence of the dimerization series (see figure 6). Thus, the dimer derivatives containing
on the molecular organization, the variation of the anion the singly-charged anion, i.e. the spherical Br- or the linear
resulted in a huge evolution of the polymorphism within the [Ag(CN)2]- (2a), exhibit the smectic A phase over a similar
temperature range. The smectic phase vanishes on the that the anion's main axis is strongly tilted with respect to the
contrary with the doubly-charged and square-planar [Ni(CN)4]2- normal layer, in order to project a large area in the plane layer.
(
2b), but reappears over an extended temperature range with Indeed the crystalline lattice contains an alternation of rows of
the octahedral multiply-charged hexacyanometallates.
imidazolium cations and rows of the anions, with a 6.42 Å
spacing within rows and with the anions'axis tilted by about
60° with respect to the layer normal. This large tilt angle draws
the negative charges borne by the cyano groups back into the
interior of the layer. Still larger tilt angles are excluded since
they would expand the imidazolium rows and therefore reduce
the ionic layer compactness. This organization is probably
preserved on the local range in the ruffled layers of the
smectic phase, as suggested by the similar ratios of molecular
areas in both phases between the [Ag(CN)2]- (2a) and Br- (
1)
derivatives.
The [Ni(CN)4]2-
(2b) derivative melts directly in the isotropic
phase without crossing a smectic phase with ruffled ionic
layers. Reasons for this singularity in the metallocyanate series
can be found in the structure of the low-temperature
crystalline phase. Thus, one may have expected that the four
negatively charged cyano groups of the square-planar complex
would just intercalate between the imidazolium rows in the
interior of the ionic layers. However the real structure consist
in an alternation of two rows of imidazoliums and of one row
of anions, with 8.84 Å spacing within rows and with a strongly
tilted orientation of the plane of the complex anion with
respect to the layer plane. More precisely, one diagonal of the
[Ni(CN)4]2- square is tilted by about 85° from the layer normal,
burying two cyano groups in the ionic layer, while the other
diagonal is tilted by about 45°, posing the two other cyano
groups at the ionic layer boundaries. The flat shape of the
Figure 7: Polymorphism variations in a bolaamphiphile series with various counter-
anions.
The molecular areas in the mesophase and crystal structures
might elucidate the variation within the anion series. In fact,
molecular areas in the mesophase dimer are about 10 percent
greater with [Ag(CN)2]- (2a) than with bromide (see Figure 7),
in agreement with the discrepancy found between crystalline
phases of corresponding monomers (46.7 Å2 with [Ag(CN)2]-
(
2a) and 42.6 Å2 with Br- (
1)). This is in in accordance with the
slightly larger overall size of the cyanometallate, but implies
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Figure 8: Variation with temprature of the molecular area in the smectic A phase for
the bolaamphiphile series with various counter-ions.
complex is obviously the reason for this tilted orientation since
it optimizes the space filling between the imidazolium rows.
An explanation of the absence of a mesophase may be that the
cyano groups, at the layer boundaries, are less strongly
retained in position by ionic bonds than the ones buried inside
the layer. Therefore contribute weakly to the lateral cohesion
of the ionic layers. After melting, mobility and disorder are
introduced in the packing, the long range ordered piling of
segregated sublayers then collapse rather than being
preserved with ruffled ionic layers as in the case of the anions
with other geometries.
molecular organization would necessitate crystal structure
determinations but none of these salts could be obtained in a
suitable form.
Conclusions
We report the full characterisation of new mesomorphic
bolaforms based on bis(imidazolium) units. The cation-anion
organization has been determined in the solid state in two
different cases by Single-Crystal X-ray diffraction and for the
whole series in the mesophase by Small-Angle X-ray Scattering.
The bis-imidazolium, “dimer” cation appears to be a versatile
smectogenic platform which promotes mesomorphic behavior
with different mono- and poly-charged cyanometallates of
linear or octahedral geometry as in [Ag(CN)2]- (2a), [Co(CN)6]3-
The dimer derivatives containing an octahedral multiply-
charged hexacyanometallate all exhibit the smectic A phase
over an extended temperature range, up to their degradation
temperature about 100°C above that of the isotropization of
the dimer bromide (see Figure 6). Indeed, the comparison with
the bromide is more relevant than for the other
cyanometallates, as the octahedral shape is closer to spherical
and the area projected in the layer plane defining the
molecular area changes little with the orientation of the anion.
Based on that spherical shape approximation, the contribution
of all hexacyanometallates to the molecular area was deduced
from partial volumes in reference salts. By assuming that the
ionic layers of all dimer hexacyanometallates exhibit the same
degree of ruffling as the dimer bromide, the molecular areas
(2d), [Fe(CN)6]3-
(
2e
)
and [Fe(CN)6]4-
2c) are not conducive to the
(2f). Square planar
[Ni(CN)4]2- 2b) and [Pt(CN)4]2-
(
(
emergence of liquid crystal properties. All the
metallomesogens display lamellar self-organization (Smectic A
phase). We have investigated the temperature dependence of
the layer thickness of the Smectic A phase as a function of the
temperature and different anions and we are now attempting
to introduce different lateral tails to obtain room-temperature
ionic liquid crystals.
for both salts of the triply-charged complexes ([Co(CN)6]3-
and [Fe(CN)6]3- 2e)) would be similar and 3.5 Å2 greater than
that of the Br- (
) while the salt of the quadruply-charged
complex [Fe(CN)6]4- 2f) would be 3 Å2 smaller. Exact molecular
(2d)
(
1
(
Materials and methods
areas can indeed not be predicted with these approximations
(see Figure 8), but the sequence of molecular areas is
respected and the order of magnitude for the discrepancies is
correct, justifying nonetheless that the ruffled-layer model
developed for the mono-charged anions is also relevant for the
General Synthetic Methods. Reagents and solvents were
purchased from commercial sources (Aldrich, Acros, Fluka) and
used without further purification unless otherwise specified.
Dichloromethane (CH2Cl2) was distilled from CaH2 under argon.
hexacyanometallates.
Particularities
of
the
Tetrahyfrofuran
(THF)
under
was
argon.
distilled
Flash
from
hexacyanometallate derivatives consist in the enlarged smectic
ranges and in the less steep variation with temperature of the
molecular areas, revealing the reinforced lateral interactions
between the imidazolium rows and the multi-charged anions.
Confirmation and a more detailed investigation of the
sodium/benzophenone
column
chromatography was performed using Merck Aluminium oxide
90.
1H (300.13 MHz) and 13C NMR (75.48 MHz) spectra
were recorded on Bruker Avance 300 spectrometer.
a
Chemical shifts (δ) are given in parts per million (ppm)
referenced to residual protonated solvent (CDCl3: δH 7.27 ppm,
δC 77.00 ppm; DMSO-d6: δH 2.50 ppm, δC 39.50 ppm;
methanol-d4: δH 3.35 ppm, δC 49.00 ppm). Abbreviations used
are s (singlet), d (doublet), t (triplet), br (broad) and m
(multiplet). FT-IR spectra were recorded on IR Digilab FTS 3000
spectrophotometer. Frequencies are given in cm-1.
Abbreviations used are br (broad), s (strong), m (medium) and
w (weak). UV spectra were recorded on a Perkin Elmer Lambda
950 UV/Visible Spectrophotometer. Wavelengths are given in
nm and the molar absorption coefficient in L mol-1 cm-1.
Elemental analyses were performed by the Institute Charles
Sadron (ICS). The transition temperatures and enthalpies were
measured by differential scanning calorimetry with a DSC
Q1000 from TA Instruments operated at heating/cooling rate
of 5°C/min. The device was calibrated with indium (156.6 °C,
28.4 J g-1) and gallium (29.8 °C) as the standards. The TGA
measurements were carried out on a SDTQ 600 apparatus at
6 | J. Name., 2012, 00, 1-3
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DOI: 10.1039/C6NJ03590F
Journal Name
ARTICLE
scanning rate of 10 °C min-1. Polarized optical microscopy
studies: the optical texture of the mesophases were studied
with a Leitz Orthoplan polarizing microscope equipped with a
Mettler FP80 hot-stage and an FP80 central processor. SAXS
measurements were recorded either on a curved counter
(CPS120 model from INEL) or on image plates (scanned by
STORM 820 from Molecular Dynamics with 50 µm resolution).
The setup consists in a transmission Guinier-like geometry, the
linear focalized monochromatic Cu Kα1 beam (λ = 1.54056 Å)
being obtained with a sealed-tube generator equipped with a
bent quartz monochromator. For our compounds, the sample
was directly filled in Lindemann capillaries of 0.5 mm
diameter.
over 2 h and the resulting white suspension was then heated
at 80 ºC for 16 h. After cooling, the precipitate was collected
by filtration and washed with water (100 mL). It was then
treated with a mixture of CH2Cl2 and water until all solids had
dissolved. The organic phase was separated and the aqueous
solution was extracted with CH2Cl2. All organics were
combined and washed successively with saturated aqueous
NaHCO3, water, and brine. The CH2Cl2 layer was dried over
MgSO4, filtered and dried under vacuum to give a pure white
1
solid (35.85 g, quantitative). H NMR (CDCl3; 300 MHz): δ 1.31
(br s, 12H, CH2 aliphatic chain), 1.45 (m, 4H, J = 6.72 Hz, CH2
aliphatic chain), 1.80 (m, 4H, J = 6.59 Hz, CH2– CH2–O), 3.88 (s,
6H, CH3–O), 4.00 (t, 4H, 3J = 6.59 Hz, CH2–O), 6.90 (m, 4H,
aromatic, BB’ system, J = 8.78 Hz), 7.98 (m, 4H, aromatic, AA’
system, J = 8.78 Hz). 13C NMR (CDCl3; 75 MHz): δc 25.94, 29.08,
29.30, 29.49 (CH2 aliphatic chain), 51.75 (CH3–O), 68.15 (CH2–
O), 114.02 (CH phenyl), 122.30 (C phenyl), 131.51 (CH phenyl),
X-ray single crystal structure determinations of 2a and 2b
The selected crystals have been mounted on a Nonius Kappa-
162.92 (C phenyl), 166.85 (C=O ester). IR (KBr, cm-1): νmax
=
CCD area detector diffractometer (Mo Kα, λ=0.71073 Å). The
complete conditions of data collection (Denzo software) 37
and structure refinements are given in the corresponding cif
file. The cell parameters were determined from reflections
taken from one set of ten frames (1.0° steps in phi angle), each
at 20 s exposure. The structures were solved using direct
methods (SHELXS97)38 and refined against F2 using the
SHELXL97 software. The absorption was not corrected. All non-
hydrogen atoms were refined anisotropically. Hydrogen atoms
were generated according to stereo-chemistry and refined
2920 (m, C–H aliphatic), 2850 (m, C–H aliphatic), 1723 (s, C=O
ester), 1607 (m, C=C aromatic), 1507 (m, C=C aromatic), 1109
(m, C–O ester), 768 (m, C–H aromatic).
Synthesis of 1,12-bis(4-(hydroxymethyl)phenoxy)dodecane.
A solution of 1 (35.85 g, 76.18 mmol) dissolved in dry THF (150
mL) under argon was cooled to 0 ºC. Lithium aluminium
hydride (1.0M in THF – 76.18 mL) was slowly added to the
stirred solution and the resulting mixture was stirred under
argon for 20 h at room temperature. It was then quenched
with EtOH (50 mL), followed by water (25 mL) and the mixture
formed was acidified with concentrated HCl to pH=1. It was
next extracted with CH2Cl2. and the combined organic extracts
washed successively with saturated aqueous NaHCO3, water,
and brine. They were finally dried over MgSO4, filtered and
evaporated to dryness to afford a pure white solid (29.92 g,
95%). 1H NMR (DMSO; 300 MHz): δ 1.26 (br s, 12H, CH2
aliphatic chain), 1.38 (m, 4H, CH2 aliphatic chain), 1.67 (m, 4H,
J = 6.04 Hz, CH2– CH2–O), 3.91 (t, 4H, 3J = 6.59 Hz, CH2–O), 4.38
(d, 4H, J = 5.21 Hz, CH2–OH), 5.01 (t, 2H, HO–CH2, 3J = 5.49 Hz),
6.84 (d, 4H, aromatic, J = 8.51 Hz), 7.19 (d, 4H, aromatic, J =
8.51 Hz). 13C NMR (DMSO; 75 MHz): δc 25.46, 28.65, 28.71,
28.90, 28.93 (CH2 aliphatic chain), 62.52 (CH2–OH), 67.33 (CH2–
O), 113.96 (CH phenyl), 127.84 (CH phenyl), 134.33 (C phenyl),
157.52 (C phenyl). IR (KBr, cm-1): νmax = 3331 (br, OH), 2919 (s,
C–H aliphatic), 2851 (s, C–H aliphatic), 1611 (m, C=C aromatic),
1510 (s, C=C aromatic), 1252 (s, methyl alkyl), 1028 (s, C–O
alcohol), 817 (m, C–H aromatic).
using
a riding model in SHELXL97, excepted for water
molecules in 2b. Crystallographic data have been deposited in
the Cambridge Crystallographic Data Centre as Supplementary
publication CCDC reference numbers (2a: 1496539 and 2b
:
1496540). This material is available free of charge via the
Internet at http://www.ccdc.cam.ac.uk.
Crystal data and structure refinement details summary (T=173
K):
2a: colorless crystal; crystal dimension: 0.15
C34H48N4O2, 2(AgCN2), M=864.58 g.mol-1; triclinic; space group
P-1; a = 6.420(1) Å; b = 6.924(1) Å; c = 22.131(2) Å;
95.130(2)°; = 92.580(2)°; = 100.820(3)°; Z = 1; Dc = 1.495
g.cm-3; )= 1.063 mm-1; a total of 8953 reflections;
(Mo K
1.85°< <30.03°, 5559 independent reflections with 4694
having I > 2 (I); 226 parameters; Final results: R1= 0.0507;
×0.11×
0.08 mm3;
α
=
β
γ
ꢀ
α
θ
σ
wR2= 0.1229, Goof=1.047, maximum residual electronic
density = 0.9 e-.Å-3.
Synthesis of 1,12-bis(4-(bromomethyl)phenoxy)dodecane.
To a solution of 2 (4.00 g, 9.65 mmol) in dry THF (30 mL) was
added dropwise thionyl bromide (2.01 g, 9.65 mmol) under
argon. The orange mixture was stirred for 2 h at room
temperature under argon. The reaction mixture was quenched
with saturated NaHCO3 and extracted with CH2Cl2. The
combined extracts were washed with NaHCO3, dried over
MgSO4, and evaporated in vacuum to give a crude white solid
(5.07 g, 97%). 1H NMR (CDCl3; 300 MHz): δ 1.31 (br s, 12H, CH2
2b: colorless crystal; crystal dimension: 0.13
C34H48N4O2, H2O, Ni(CN)4, M=725.57 g.mol-1; triclinic; space
group P-1; a = 8.8400(3) Å; b = 9.3130(4) Å; c = 24.9890(5) Å;
×0.10×
0.07 mm3;
α
= 90.611(2)°;
β
ꢀ
= 99.078(2)°;
(Mo K
)= 0.552 mm-1; a total of 18343
<30.03°, 11122 independent reflections
with 8181 having I > 2 (I); 459 parameters; Final results: R1=
γ = 108.8990(13)°; Z = 2; c =
1.256 g.cm-3;
α
reflections; 1.65°<
θ
σ
0.0669; wR2= 0.1277, Goof=1.043, maximum residual aliphatic chain), 1.45 (m, 4H, CH2 aliphatic chain), 1.79 (m, 4H,
J = 6.59 Hz, CH2– CH2–O), 3.96 (t, 4H, 3J = 6.59 Hz, CH2–O), 4.51
(s, 4H, CH2–Br), 6.86 (m, 4H, aromatic, BB’ system, J = 9.06 Hz),
7.32 (m, 4H, aromatic, AA’ system, J = 8.78 Hz). 13C NMR
(CDCl3; 75 MHz): δc 26.00, 29.19, 29.34, 29.52 (CH2 aliphatic
chain), 34.05 (CH2–Br), 68.08 (CH2–O), 114.75 (CH phenyl),
129.69 (C phenyl), 130.38 (CH phenyl), 159.27 (C phenyl). IR
(KBr, cm-1): νmax = 2917 (m, C–H aliphatic), 2850 (m, C–H
electronic density = 0.667 e-.Å-3.
Synthetic procedures
Synthesis
diylbis(oxy))dibenzoate.
of
Dimethyl
With
4,4'-(dodecane-1,12-
continuous stirring,
dibromododecane (25.00 g, 76 mmol) was added to a mixture
of methyl 4-hydroxybenzoate (24.34 g, 160 mmol) and
potassium carbonate (31.54 g, 229 mmol) in DMF (300 mL)
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J. Name., 2013, 00, 1-3 | 7
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ARTICLE
Journal Name
aliphatic), 1611 (m, C=C aromatic), 1513 (s, C=C aromatic), 235(14432), 273(5243). Elem anal calcd (%) for C38H48Ag2N8O2,
1256 (s, methyl alkyl), 821 (m, C–H aromatic), 602 (s, C–Br).
M = 864,59: C, 52.79; H, 5.60; N, 12.96. Found: C, 52.79; H,
5.62; N, 12.63.
Procedures for the mesogenic materials preparation:
Synthesis
phenylene))bis(methylene))bis(1-methyl-1H-imidazol-3-ium)
tetracyanonickelate(II) (2b). Prepared from compound (100
of
3,3'-(((dodecane-1,12-diylbis(oxy))bis(4,1-
Synthesis
phenylene))bis(methylene))bis(1-methyl-1H-imidazol-3-ium)
bromide ( ).
of
3,3'-(((dodecane-1,12-diylbis(oxy))bis(4,1-
1
1
mg, 0.139 mmol) and potassium tetracyanonickelate(II) (35
mg, 0.142 mmol) according to the general procedure to yield
2b as a pure white solid (89 mg, 0.124 mmol, 89%). H NMR
A mixture of methylimidazole (0.32 g, 3.89 mmol) and 1,12-
bis(4-(bromomethyl)phenoxy)dodecane (1.00 g, 1.85 mmol),
dried separately under vacuum overnight, was heated at 80 ˚C
and stirred for 20 h in a sealed tube. After cooling to room
temperature, the sealed tube was broken and the resulting
solid was dissolved with dichloromethane and methanol. The
reaction mixture was concentrated to a small volume under
reduced pressure and purified via column chromatography
1
(MeOD/CD2Cl2:1/1; 300 MHz): δ 1.37 (br s, 12H, CH2 aliphatic
chain), 1.51 (m, 4H, CH2 aliphatic chain), 1.83 (m, 4H, J = 6.86
Hz, CH2– CH2–O), 4.00 (s, 6H, N–CH3), 4.04 (t, 4H, J = 6.59 Hz,
3
CH2–O), 5.39 (s, 4H, N–CH2–Ph), 7.03 (br d, 4H, aromatic, J =
8.78 Hz), 7.45 (br d, 4H, aromatic, J = 8.51 Hz), 7.54 (br s, 2H,
C4–H imidazolium), 7.55 (br s, 2H, C5–H imidazolium). 13C NMR
(CDCl3; 75 MHz): δc 26.60, 29.80, 29.84, 29.86, 30.02, 30.09
(CH2 aliphatic chain), 36.75 (CH3–N), 53.76 (N–CH2–Ph), 68.92
(CH2–O), 116.06 (CH phenyl), 123.06 (C5–H imidazolium),
124.86 (C4–H imidazolium), 125.83 (C phenyl), 131.21 (CH
phenyl), 133.69 (C2–H imidazolium), 161.02 (C phenyl). IR (KBr,
cm-1): νmax = 2923 (w, C–H aliphatic), 2854 (w, C–H aliphatic),
2119 (m, C≡N), 1607 (s, C=C aromaꢀc), 1516 (m, C=C
aromatic), 1255 (s, methyl alkyl), 837 m, (C–H aromatic). UV–
vis (MeOH): λ(ε) = 237(12540), 267(16973). Elem anal calcd (%)
for C38H48NiN8O2·0.5H2O, M = 716,56: C, 63.70; H, 6.89; N,
15.64. Found: C, 63.79; H, 6.88; N, 15.36.
(gradient 100/0 to 95/10: CH2Cl2/methanol) to furnish
1 (1.05
g, 1.46mmol, 79%) as a white solid. 1H NMR (MeOD; 300 MHz):
δ 1.40 (br s, 12H, CH2 aliphatic chain), 1.52 (m, 4H, CH2
aliphatic chain), 1.83 (m, 4H, J = 6.57 Hz, CH2–CH2–O), 3.99 (s,
3
6H, N–CH3), 4.30 (t, 4H, J = 6.60 Hz, CH2–O), 5.41 (s, 4H, N–
CH2–Ph), 7.03 (m, 4H, aromatic, BB’ system, J = 8.79 Hz), 7.45
3
(m, 4H, aromatic, AA’ system, J = 8.79 Hz), 7.63 (br t, 2H, J =
3
1.65 Hz, C5–H imidazolium), 7.66 (br t, 2H, J = 1.92 Hz, C4–H
imidazolium), 9.06 (2H, s, C2–H imidazolium). 13C NMR (MeOD;
75 MHz): δc 27.09, 30.26, 30.43, 30.63 (CH2 aliphatic chain),
36.58 (CH3–N), 53.73 (N–CH2–Ph), 69.15 (CH2–O), 116.25 (CH
phenyl), 123.45 (C5–H imidazolium), 125.13 (C4–H
imidazolium), 126.75 (C phenyl), 131.40 (CH phenyl), 137.67
Synthesis
phenylene))bis(methylene))bis(1-methyl-1H-imidazol-3-ium)
tetracyanoplatinate(II) (2c). Prepared from compound (100
of
3,3'-(((dodecane-1,12-diylbis(oxy))bis(4,1-
(C2–H imidazolium), 161.37 (C phenyl). IR (KBr, cm-1): νmax
=
1
2922 (m, C–H aliphatic), 2854 (m, C–H aliphatic), 1608 (s, C=C
aromatic), 1517 (s, C=C aromatic), 1252 (s, methyl alkyl), 836
mg, 0.139 mmol) and potassium tetracyanoplatinate(II) (66
mg, 0.142 mmol) according to the general procedure to yield
2c as a pure white solid (109 mg, 0.129 mmol, 93%). H NMR
(m, C–H aromatic). UV–vis (MeOH): λ(ε)
= 231(5568),
1
271(2811). Elem. anal. calcd (%) for C34H48Br2N4O2·0.75H2O, M
= 718,10: C, 56.87; H, 6.95; N, 7.80. Found: C, 56.90; H, 6.94; N,
7.54.
(MeOD/CD2Cl2:1/1; 300 MHz): δ 1.37 (br s, 12H, CH2 aliphatic
chain), 1.51 (m, 4H, CH2 aliphatic chain), 1.82 (m, 4H, J = 6.86
Hz, CH2– CH2–O), 4.00 (s, 6H, N–CH3), 4.04 (t, 4H, J = 6.59 Hz,
3
General procedure for compounds 2a to 2f anion metathesis of 1.
CH2–O), 5.39 (s, 4H, N–CH2–Ph), 7.02 (m, 4H, aromatic, BB’
system, J = 8.78 Hz), 7.43 (m, 4H, aromatic, AA’ system, J =
8.78 Hz), 7.49 (br d, 2H, J = 1.92 Hz, C5–H imidazolium), 7.52
A solution of potassium cyanometallate dissolved in water (4
mL) was added to a solution of compound 1 dissolved in
methanol (6 mL). The solution was stirred at room
temperature during ten days. The resulting precipitate was
filtered and washed with water. Then, the solid was dried
under reduced pressure. No further purification was required.
(br d, 2H,
J =
1.92 Hz, C4–H imidazolium). 13C NMR
(MeOD/CD2Cl2:1/1; 75 MHz): δc 26.54, 26.57, 29.73, 29.80,
29.96, 30.03 (CH2 aliphatic chain), 36.78 (CH3–N), 53.74 (N–
CH2–Ph), 68.87 (CH2–O), 116.00 (CH phenyl), 123.03 (C5–H
imidazolium), 124.73 (C4–H imidazolium), 125.57 (C phenyl),
Synthesis
phenylene))bis(methylene))bis(1-methyl-1H-imidazol-3-ium)
dicyanoargentate(I) (2a). Prepared from compound (100 mg,
of
3,3'-(((dodecane-1,12-diylbis(oxy))bis(4,1-
131.20 (CH phenyl), 160.91 (C phenyl). IR (KBr, cm-1): νmax
=
1
2922 (m, C–H aliphatic), 2852 (m, C–H aliphatic), 2124 (s, C≡N),
1516 (s, C=C aromatic), 1254 (s, methyl alkyl), 835 (m, C–H
aromatic). Elem anal calcd (%) for C38H48N8O2Pt, M = 843.94: C,
54.08; H, 5.73; N, 13.28. Found: C, 54.15; H, 5.75; N, 12.78.
0.139 mmol) and potassium dicyanoargentate(I) (57 mg, 0.284
mmol) according to the general procedure to yield 2a as a pure
white solid (107 mg, 0.124 mmol, 89%). 1H NMR
(MeOD/CD2Cl2:1/1; 300 MHz): δ 1.38 (br s, 12H, CH2 aliphatic
chain), 1.52 (m, 4H, CH2 aliphatic chain), 1.84 (m, 4H, J = 6.59
Synthesis
of
3,3'-(((dodecane-1,12-diylbis(oxy))bis(4,1-
3
phenylene))bis(methylene))bis(1-methyl-1H-imidazol-3-ium)
hexacyanocobaltate(III) (2d). Prepared from compound 1 (100
mg, 0.139 mmol) and potassium hexacyanocobaltate(III) (32
mg, 0.095 mmol) according to the general procedure to yield
Hz, CH2– CH2–O), 3.97 (s, 6H, N–CH3), 4.04 (t, 4H, J = 6.04 Hz,
CH2–O), 5.34 (s, 4H, N–CH2–Ph), 7.03 (m, 4H, aromatic, BB’
system, J = 8.78 Hz), 7.39 (4H, m, aromatic, AA’ system, J =
8.78 Hz), 7.54 (br s, 4H, C4–H imidazolium and C5–H
imidazolium), 8.92 (s, 2H, C2–H imidazolium). 13C NMR
(MeOD/CD2Cl2:1/1; 75 MHz): δc 26.72, 29.89, 30.11, 30.29,
30.90, 30.91 (CH2 aliphatic chain), 36.57 (CH3–N), 53.74 (N–
CH2–Ph), 69.02 (CH2–O), 116.08 (CH phenyl), 123.15 (C5–H
imidazolium), 124.76 (C4–H imidazolium), 125.50 (C phenyl),
1
2d as a pure white solid (91 mg, 0.043 mmol, 92%). H NMR
(MeOD/CD2Cl2:1/1; 300 MHz): δ 1.37 (br s, 12H, CH2 aliphatic
chain), 1.49 (m, 4H, CH2 aliphatic chain), 1.81 (m, 4H, J = 6.31
Hz, CH2– CH2–O), 4.00 (t, 4H, J = 6.45 Hz, CH2–O), 4.06 (s, 6H,
3
N–CH3), 5.44 (s, 4H, N–CH2–Ph), 6.97 (m, 4H, aromatic, BB’
system, J = 8.51 Hz), 7.42 (br t, 2H, 3J = 1.92 Hz, C5–H
imidazolium), 7.44 (m, 4H, aromatic, AA’ system, J = 8.78 Hz),
131.02 (CH phenyl), 161.13 (C phenyl). IR (KBr, cm-1): νmax
=
2923 (w, C–H aliphatic), 2853 (w, C–H aliphatic), 2127 (w,
C≡N), 1607 (s, C=C aromaꢀc), 1516 (m, C=C aromaꢀc), 1253 (s,
methyl alkyl), 832 (w, C–H aromatic). UV–vis (MeOH): λ(ε) =
3
7.50 (br t, 2H, J = 1.78 Hz, C4–H imidazolium), 9.12 (br s, 2H,
C2–H imidazolium). 13C NMR (MeOD/CD2Cl2:1/1; 75 MHz): δc
8 | J. Name., 2012, 00, 1-3
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Journal Name
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DOI: 10.1039/C6NJ03590F
ARTICLE
26.47, 29.68, 29.80, 29.92 (CH2 aliphatic chain), 36.95 (CH3–N),
53.60 (N–CH2–Ph), 68.78 (CH2–O), 115.84 (CH phenyl), 122.63
(C5–H imidazolium), 124.64 (C4–H imidazolium), 126.15 (C
phenyl), 131.20 (CH phenyl), 137.14 (C2–H imidazolium),
160.69 (C phenyl). IR (KBr, cm-1): νmax = 2921 (w, C–H aliphatic),
2854 (w, C–H aliphatic), 2134 (w, C≡N), 1605 (s, C=C aromaꢀc),
1516 (C=C aromatic), 1254 (m, methyl alkyl), 833 (w, C–H
aromatic). UV–vis (MeOH): λ(ε) = 235(10811), 273(5730). Elem
anal calcd (%) for C114H144Co2N24O6·3.5H2O, M = 2127,49: C,
64.36; H, 7.15; N, 15.80. Found: C, 64.31; H, 7.18; N, 15.49.
University of Strasbourg (Unistra), Centre National de la
Recherche Scientifique (C.N.R.S., grant of Alexandre Al Abbas)
and the Institute for Physics and Chemistry of Materials
Strasbourg (I.P.C.M.S.).
Notes and references
1.
P. Wasserscheid and T. Welton, Ionic liquids in synthesis,
Wiley-VCH, Weinheim, 2nd, completely rev. and enl. edn.,
2008.
Synthesis
phenylene))bis(methylene))bis(1-methyl-1H-imidazol-3-ium)
hexacyanoferrate(III) (2e). Prepared from compound (100
of
3,3'-(((dodecane-1,12-diylbis(oxy))bis(4,1-
2.
3.
4.
5.
6.
7.
H. Ohno, Electrochemical aspects of ionic liquids, Wiley,
Hoboken, N.J., 2nd edn., 2011.
M. Deetlefs, M. Fanselow and K. R. Seddon, Rsc Adv,
2016, 6, 4280-4288.
R. D. Rogers and K. R. Seddon, Science, 2003, 302, 792-
793.
F. Endres and S. Z. El Abedin, Phys Chem Chem Phys, 2006,
8, 2101-2116.
M. C. Buzzeo, R. G. Evans and R. G. Compton,
Chemphyschem, 2004, 5, 1106-1120.
P. Bonhote, A. P. Dias, N. Papageorgiou, K.
Kalyanasundaram and M. Gratzel, Inorg Chem, 1996, 35,
1168-1178.
1
mg, 0.139 mmol) and potassium hexacyanoferrate (III) (32 mg,
0.095 mmol) according to the general procedure to yield 2e as
1
a pure dark yellow solid (91 mg, 0.043 mmol, 92%). H NMR
(MeOD/CD2Cl2:1/1; 300 MHz): δ 1.37 (br s, 12H, CH2 aliphatic
chain), 1.49 (m, 4H, CH2 aliphatic chain), 1.80 (m, 4H, J = 6.04
Hz, CH2– CH2–O), 3.59 (s, 6H, N–CH3), 3.99 (t, 4H, J = 6.31 Hz,
3
CH2–O), 5.01 (s, 4H, N–CH2–Ph), 6.92 (br d, 4H, aromatic, J =
8.23 Hz), 7.13 (br s, 2H, C5–H imidazolium), 7.14 (br s, 2H, C4–H
imidazolium), 7.23 (br d, 4H, aromatic, J = 8.23 Hz), 7.94 (br s,
2H, C2–H imidazolium). 13C NMR (MeOD/CD2Cl2:1/1; 75 MHz):
δc 26.55, 29.76, 29.89, 30.00 (CH2 aliphatic chain), 40.04 (CH3–
N), 55.59 (N–CH2–Ph), 68.83 (CH2–O), 115.94 (CH phenyl),
123.45 (C5–H imidazolium), 125.55 (C4–H imidazolium), 126.06
(C phenyl), 131.67 (CH phenyl), 141.06 (C2–H imidazolium),
160.74 (C phenyl). IR (KBr, cm-1): νmax = 2919 (m, C–H aliphatic),
2851 (m, C–H aliphatic), 2106 (s, C≡N), 1612 (s, C=C aromaꢀc),
1514 (s, C=C aromatic), 1250 (s, methyl alkyl), 836 (s, C–H
aromatic). UV–vis (MeOH): λ(ε) = 234(11351), 273(3514), 420
(≈ 55 ) Elem anal calcd (%) for C114H144Fe2N24O6·3.75.H2O, M =
2125,81: C, 64.41; H, 7.18; N, 15.81. Found: C, 64.19; H, 7.19;
N, 15.39.
8.
N. Papageorgiou, Y. Athanassov, M. Armand, P. Bonhote,
H. Pettersson, A. Azam and M. Gratzel, J Electrochem Soc,
1996, 143, 3099-3108.
9.
P. Wang, S. M. Zakeeruddin, J. E. Moser and M. Gratzel, J
Phys Chem B, 2003, 107, 13280-13285.
10.
11.
J. W. Goodby, Handbook of liquid crystals, Wiley-VCH,
Weinheim, 2nd, compl. rev. and greatly enl. edn., 2014.
J. W. Goodby, I. M. Saez, S. J. Cowling, V. Gortz, M.
Draper, A. W. Hall, S. Sia, G. Cosquer, S. E. Lee and E. P.
Raynes, Angew Chem Int Edit, 2008, 47, 2754-2787.
G. R. Luckhurst, Macromol Symp, 1995, 96, 1-26.
K. Goossens, K. Lava, C. W. Bielawski and K. Binnemans,
Chem. Rev., 2016, 116, 4643-4807.
12.
13.
Synthesis
phenylene))bis(methylene))bis(1-methyl-1H-imidazol-3-ium)
hexacyanoferrate (II) (2f). Prepared from compound (100
of
3,3'-(((dodecane-1,12-diylbis(oxy))bis(4,1-
1
14.
15.
A. Tiwari and A. P. F. Turner, Biosensors nanotechnology,
Wiley, 2014.
M. Moosavi, F. Khashei, A. Sharifi and M. Mirzaei, Ind Eng
Chem Res, 2016, 55, 9087-9099.
mg, 0.139 mmol) and potassium hexacyanoferrate (II) (30 mg,
0.071 mmol) according to the general procedure to yield 2f as
a pure yellow solid (83 mg, 0.062 mmol, 89%). 1H NMR
(MeOD/CD2Cl2:1/1; 300 MHz): δ 1.37 (br s, 12H, CH2 aliphatic
chain), 1.49 (m, 4H, CH2 aliphatic chain), 1.81 (m, 4H, J = 6.59
Hz, CH2– CH2–O), 3.99 (m, 10H, CH2–O and N–CH3), 5.40 (s, 4H,
N–CH2–Ph), 6.94 (m, 4H, aromatic, BB’ system, J = 8.51 Hz),
7.29 (br d, 2H, J = 1.92 Hz, C5–H imidazolium), 7.39 (m, 4H,
aromatic, AA’ system and C4–H imidazolium). 13C NMR
(MeOD/CD2Cl2:1/1; 75 MHz): δc 25.66, 28.88, 29.00, 29.11 (CH2
aliphatic chain), 37.13 (CH3–N), 53.21 (N–CH2–Ph), 67.96 (CH2–
O), 114.98 (CH phenyl), 121.69 (C5–H imidazolium), 123.86 (C4–
H imidazolium), 125.43 (C phenyl), 130.46 (CH phenyl), 159.95
(C phenyl). IR (KBr, cm-1): νmax = 2922 (w, C–H aliphatic), 2854
(w, C–H aliphatic), 2044 (m, C≡N), 1607 (s, C=C aromaꢀc), 1517
(m, C=C aromatic), 1256 (s, methyl alkyl), 835 (m, C–H
aromatic). UV–vis (MeOH): λ(ε) = 235(9189), 273(3730) 425 (≈
85). Elem anal calcd (%) for C74H96FeN14O4·2H2O, M = 1337.55:
C, 66.45; H, 7.54; N, 14.66. Found: C, 66.32; H, 7.50; N, 15.45.
16.
17.
K. V. Axenov and S. Laschat, Materials, 2011, 4, 206-259.
L. Douce, J. M. Suisse, D. Guillon and A. Taubert, Liq Cryst,
2011, 38, 1653-1661.
L. Veltri, V. Maltese, F. Auriemma, C. Santillo, S. Cospito,
M. La Deda, G. Chidichimo, B. Gabriele, C. De Rosa and A.
Beneduci, Cryst Growth Des, 2016, 16, 5646-5656.
R. A. Patil, M. Talebi, C. D. Xu, S. S. Bhawal and D. W.
Armstrong, Chem Mater, 2016, 28, 4315-4323.
J. L. Anderson, R. F. Ding, A. Ellern and D. W. Armstrong, J
Am Chem Soc, 2005, 127, 593-604.
M. Trilla, R. Pleixats, T. Parella, C. Blanc, P. Dieudonne, Y.
Guari and M. W. C. Man, Langmuir, 2008, 24, 259-265.
J. E. Bara, E. S. Hatakeyama, B. R. Wiesenauer, X. H. Zeng,
R. D. Noble and D. L. Gin, Liq Cryst, 2010, 37, 1587-1599.
L. A. Robertson, M. R. Schenkel, B. R. Wiesenauer and D.
L. Gin, Chem Commun, 2013, 49, 9407-9409.
M. R. Schenkel, R. Shao, L. A. Robertson, B. R.
Wiesenauer, N. A. Clark and D. L. Gin, Liq Cryst, 2013, 40,
1067-1081.
18.
19.
20.
21.
22.
23.
24.
Acknowledgements
We are especially grateful to Dr. Jack Harrowfield for the ritical
evaluation of this manuscript. This work was supported by
25.
M. Yang, K. Stappert and A. V. Mudring, J Mater Chem C,
2014, 2, 458-473.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 9
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Page 10 of 11
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DOI: 10.1039/C6NJ03590F
ARTICLE
26.
Journal Name
M. R. Schenkel, J. B. Hooper, M. J. Moran, L. A. Robertson,
D. Bedrov and D. L. Gin, Liq Cryst, 2014, 41, 1668-1685.
A. Bhadani, T. Misono, S. Singh, K. Sakai, H. Sakai and M.
Abe, Adv Colloid Interfac, 2016, 231, 36-58.
W. Andrzejewska, Z. Pietralik, M. Skupin and M. Kozak,
Colloid Surface B, 2016, 146, 598-606.
27.
28.
29.
T. Fahlbusch, M. Frank, J. Schatz and D. T. Schuhle, J Org
Chem, 2006, 71, 1688-1691.
30.
T. Fahlbusch, M. Frank, J. Schatz and H. Schmaderer, Eur J
Org Chem, 2006, DOI: 10.1002/ejoc.200500825, 1899-
1903.
31.
32.
33.
34.
35.
36.
37.
38.
W. Dobbs, L. Douce, L. Allouche, A. Louati, F. Malbosc and
R. Welter, New J Chem, 2006, 30, 528-532.
W. Dobbs, J. M. Suisse, L. Douce and R. Welter, Angew
Chem Int Edit, 2006, 45, 4179-4182.
W. Dobbs, L. Douce and B. Heinrich, Beilstein J Org Chem,
2009, 5.
J. Fouchet, L. Douce, B. Heinrich, R. Welter and A. Louati,
Beilstein J Org Chem, 2009, 5.
J. Watanabe, H. Komura and T. Niiori, Liq Cryst, 1993, 13,
455-465.
M. Hanford and T. L. Peeples, Appl Biochem Biotech, 2002,
97, 45-62.
Kappa CCD Operation Manual, The Netherlands, Delft
edn., 1997.
G. M. Sheldrick, SHELXL97, Program for the Refinement of
Crystal Structures, University of Göttingen, 1997,
Göttingen, Germany.
10 | J. Name., 2012, 00, 1-3
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Table of contents entry
Rare examples of bolaform ionic materials containing cyanometallates and their lamellar
mesormorphic supramolecular architectures are characterized.
Bolaform Ionic liquid crystal
Ri
rt
gi
d pa
d pa
gi
N
rt
N
Ri
N
N
Flexible part
n
n-
n-
M(CN)x
M(CN)x