Synthesis and self-assembly of luminescent hexacatenar molecules incorporating a 4,7-diphenyl-2,1,3-benzothiadiazole core

Article abstract of DOI:10.1039/c5ra25242c

A new polycatenar liquid crystal containing a 4,7-diphenyl-2,1,3-benzothiadiazole core and three alkoxy chains at each end has been synthesized via a copper-catalyzed azide-alkyne click reaction and investigated by polarizing microscopy, DSC, XRD scattering, SEM, UV-vis spectroscopy and photoluminescence measurements. This compound can self-assemble into an oblique columnar liquid crystalline phase in the bulk state and form organogels in different organic solvents. It shows highly fluorescent emission with large Stokes shift in solution and has binding selectivity to Li⁺ among a series of cations in DMSO-CH₂Cl₂ solution.

Full text of DOI:10.1039/c5ra25242c

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Synthesis and self-assembly of luminescent hexacatenar molecules
incorporating a 4,7-diphenyl-2,1,3-benzothiadiazole core
Danxiang Huang,a Marko Prehm,b Hongfei Gao,a Xiaohong Cheng,a* Yongsong Liu,c*
Carsten Tschierskeb
[a]
Key Laboratory of Medicinal Chemistry for Natural Resources, Chemistry Department
Yunnan University
Kunming, Yunnan 650091,
P. R. China
Fax: (+86) 871 5032905
Eꢀmail: xhcheng@ynu.edu.cn
[b] Institute of Chemistry, Organic Chemistry
MartinꢀLuther University HalleꢀWittenberg
KurtꢀMothes Str. 2,
06120 Halle/Saale,
Germany
[c] Department of Physics
Zhejiang SciꢀTech University
Hangzhou 310018, P. R. China
Fax: (+86) 571ꢀ86843754
Eꢀmail: yongsongliu@zstu.edu.cn
Abstract: A new polycatenar liquid crystal I containing a 4,7ꢀdiphenylꢀ2,1,3ꢀbenzothiadiazole
core and three alkoxy chains at each end has been synthesized via copper catalyzed azideꢀalkyne
click reaction and investigated by polarizing microscopy, DSC, XRD scattering, SEM, UVꢀvis
spectroscopy and photoluminescence measurements. This compound can selfꢀassemble into an
oblique columnar liquid crystalline phase in the bulk state and form organogels in different organic
solvents. It shows highly fluorescent emission with large Stokes shift in solution and has binding
selectivity to Li+ among a series of cations in DMSOꢀCH2Cl2 solution.
Key words: benzothiadiazole; columnar liquid crystal; organogel; fluorescent chemosensor;
azideꢀalkyne click reaction
1. Introduction
Design of lowꢀmolecularꢀweight linear πꢀconjugated molecules which can selfꢀorganize into
ordered nanostructures with potential nanotechnological application is of current interest.1 Liquid
crystals (LCs)2 represent soft selfꢀassembled materials with significant technological importance2,3
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and provide routes to increase complexity in soft selfꢀassembly.4 Physical gels with fibrous
aggregates formed by oneꢀdimensional (1D) selfꢀassembly of molecules in solvents have also
attracted a great deal of attention not only as an interesting mode of selfꢀassembly, but also for
various potential application such as photovoltaics,5 ,6 templating,7 controlled drug release,8
energy transfer9 and others. Molecules that can exhibit both, liquid crystalline and gelation
properties, have recently been reported.10
Benzothiadiazole (BTD) derived molecules are widely investigated nowadays due to their well
known photophysical properties such as high extinction coefficient, intense fluorescence,11 and
large Stokes shift,12 with potential as optical materials and chemosensors.13ꢀ18 BTD derivatives are
now also widely employed as semiconducting materials such as fieldꢀeffect transistors (FETs)
because of their high electron affinity.19 There are previous reports about LCs containing BTD
units and most of them showed smectic and nematic phases,20ꢀ27 but only few polycatenar BTD
derivatives with columnar phases have been reported so far.28,29 In some cases, liquid crystalline
BTD derivatives with SmC or nematic phases gave macroscopically ordered films with good
chargeꢀtransport properties, exhibiting good carrier mobilities which is a favorable morphology for
FET applications with improved performance.25,30
Cu(I)ꢀcatalyzed azideꢀalkyne cycloaddition (CuAAC)31 represents one of the most efficient
approaches for interconnecting smaller units to larger entities, especially for chemical
transformation to create new fluorescent molecules with desirable properties. The resulting triazole
ring could represent a πꢀconjugated core structure providing desirable materials properties.32 Few
reports about application of the CuAAC reaction for the synthesis of rodꢀlike,33 discꢀlike, star
shaped34 and bentꢀcore35 LCs have appeared quite recently. Materials with nematic, SmA, SmC
and columnar phases and in one case a bicontinuous cubic phase34d have been obtained by this
approach. We have recently reported the first use of this synthetic method for the synthesis of
polyphilic molecules forming spheroidic cubic phases with micellar and monolayer vesicular
structures.36 Chemosensors containing 2,1,3ꢀbenzothiadiazole and triazole units have been recently
reported and in all cases, the 1,2,3ꢀtriazole rings were anchored directly to the BTD units.32,37
Herein we employed the click reaction for the construction of hexacatenar mesogens
incorporating a 4,7ꢀdiphenylꢀ2,1,3ꢀbenzothiadiazole (DBTD) core and three alkoxy chains at each
terminus (Fig. 1). This compound has both, liquid crystallinity and gelation properties, and it can be
used as fluorescence chemosensor for selective response to different metal ions in solution and
therefore it can be considered as a multifunctional material.
Heating: Cr 59 ºC [88.8 kJ molꢀ1] Colob 105 ºC [13.1 kJ molꢀ1] Iso
Cooling: Iso 101 ºC [11.9 kJ molꢀ1] Colob 46 ºC [100.9 kJ molꢀ1] Cr
Fig. 1. Structure of compound I with transition temperatures (T/°C) and associated enthalpy values as determined by
DSC (peak temperatures, 5 K minꢀ1); abbreviation: Cr = crystalline solid; Colob = oblique columnar LC phase; Iso =
isotropic liquid state.
2. Results and discussion
2

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2.1 Synthesis
The target compound I was prepared by the CuAAC reaction between bispropargylether 6 and
benzyl azide 9 as shown in Scheme 1. The benzyl azide 9 was obtained by the nucleophilic
substitution of benzyl chloride 8 with sodium azide.36 Commercially available oꢀphenylenediamine
1 was treated with freshly distilled thionyl chloride in the presence of triethylamine in CH2Cl2,
affording 2,1,3ꢀbenzothiadiazole 2,38 which was dibrominated with Br2/HBr.38fꢀg The obtained
4,7ꢀdibromoꢀ2,1,3ꢀbenzothiadiazole
3
was
coupled
with
two
equivalents
of
39,40
4ꢀmethoxyꢀbenzeneboronic acid under standard Suzuki conditions with Pd(PPh3)4
and afforded
the 4,7ꢀbis(4ꢀmethoxyphenyl)ꢀ2,1,3ꢀbenzothiadiazole 4.11 Demethylation of 4 using HBr (33% in
HOAc) yielded compound 5,39 which was etherified with propargyl bromide to give the
bispropargylether 6.39 Compound 6 was used for CuAAC reaction36a with the benzyl azide 9 to
yield the target product I which was purified by column chromatography. The detailed synthetic
procedures and analytical data are given in the Supporting Information.
Scheme 1. Synthesis of compound I. Reagents and conditions: (i) SOCl2, Et3N, CH2Cl2, 93%; (ii) Br2, HBr, 95%;
(iii) 4ꢀmethoxybenzene boronic acid, Pd(PPh3)4, Cs2CO3, KF, H2O, reflux, 12 h, 60%; (iv) Bu4NBr, HBr (33% in
HOAc), 80%; (v) K2CO3, KI, propargyl bromide, 80 °C, CH3CN, 12 h, 94%; (vi) a) LiAlH4, THF, 96%; b) SOCl2,
THF, 93%; (vii) NaN3, KI, DMF, 97%; (viii) CuSO4·5H2O, Sodium ascorbate, TBA : H2O = 1 : 1, THF, 61%.
2.2 Mesomorphic properties
The LC selfꢀassembly of compound I was investigated by polarized optical microscopy (POM, Fig.
2a), differential scanning calorimetry (DSC, Fig. 2b), and Xꢀray diffraction (XRD, Fig. 2c). The
thermotropic phase sequence and the transition temperatures are shown in Fig. 1. The texture of the
LC phase observed by POM between crossed polarizers is characterized by spherulitic domains as
typical for columnar phases (Fig. 2a). Shearing the sample leads to flow which removes this texture,
this confirms the LC state of the material. The SAXS pattern of I at 100 ºC shows two strong and
two weak reflections (Fig. 2c). The small angle reflections were indexed as (10), (01), (11) and (20)
reflections of an oblique lattice41 with a = 5.1 nm, b = 4.0 nm and γ = 67° (T = 100 ºC). The
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electron density map reconstructed from the powder pattern (Fig. 2d; for alternative phase
combinations, see Fig. S1 in the Supporting Information) shows high electron density areas (blue,
purple) involving the DBTD cores, which are surrounded by a medium electron density continuum
(green) involving the benzylether groups, triazoles and some of the alkyl chains. The majority of
the alkyl chains form the low electron density areas (red), supporting the proposed organization of
the molecules in this mesophase (Fig. 2dꢀf). The number of molecules located within a hypothetical
unit cell with a height of 0.45 nm (ncell) has been calculated to be approximately two (ncell = 2.3) by
dividing the unit cell volume (Vcell = 8.44 nm3) by the molecular volume (calculated using Imirzis
increments,42 Vmol = 3.24 nm3) and assuming a packing coefficient being the average between the
crystalline (k = 0.743) and the liquid state (k = 0.55). Thus, the molecules are organized in ribbons
formed by on average two molecules arranged sideꢀby side in their cross section. The fixation of
the three alkyl chains at each end leads to a staggering of these ribbons to optimize the space filling,
thus providing the oblique 2D lattice. The long diagonal of the oblique lattice is 7.5 nm, which agrees
well with the molecular length in the stretched conformation (Lmol = 7.6 nm, see Fig 2e). Therefore, in
agreement with the electron density map, the molecules are not arranged parallel to a or b but nearly
parallel to the longer diagonal.
DSC/(mW/mg)
a)
b)
4
2
Heating
Colob
Cr
Iso
0
Cooling
Cr
Colob
-2
-4
Iso
40
60
80
100
Temperature/oC
d)
c)
4

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f)
e)
2.4 nm
2.8 nm
Fig. 2. LC phases of compound I: a) Texture of the Colob phase as seen between crossed polarizers at T = 90 ºC; b)
DSC heating and cooling scans (5 K min−1, second scans); c) SAXS diffractogram at T = 100 ºC; d) electron density
map as reconstructed from the diffraction pattern in c), for the color code, see bar on the right, e) model showing the
organization of two molecules in the cross section through a single column; f) models for the molecular arrangement
in Colob phase.
2.3 Gelation properties
The gelation ability of compound I was tested in various organic solvents at a concentration of 3.0
mg/mL and the results are summarized in Table 1. I has the ability to gel in DMF, nꢀbutanol, and
partially in cyclohexane and nꢀhexane, but it precipitates in ethyl acetate, acetone and 1,4ꢀdioxane.
A yellow gel can be obtained by cooling the heated solution of I in nꢀbutanol quickly below 20 ºC
or slowly down to room temperature. The yellow gel shows green fluorescence under irradiation
with 365 nm light (Fig. 3a, b). The solꢀgel transition temperature is 60 ºC (Fig. 3c). The
morphology of the gel was investigated by scanning electron microscopy (SEM). The SEM image
of the xerogel formed by I (Fig. 4a, b) shows the formation of threeꢀdimensional networks
composed of entangled fibrous aggregates. The approximate diameter of the fibers is 145ꢀ250 nm.
The length is more than 20 ꢁm. On the basis of this result, it is assumed that compound I forms
fibrous aggregates in the solvents.
a)
b)
c)
d)
Fig. 3. Photograph of gels prepared with I in nꢀbutanol, a,b) at T = 20 °C, a) without irradiation; b) under irradiation
with 365 nm light; c,d) heated to 65 ºC, c) without irradiation and d) under irradiation with 365 nm light.
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Table 1. Gelation properties of Ia
Solvent
I
Solvent
I
Chloroform
Ethyl acetate
THF
S
P
1,4ꢀDioxane
Cyclohexane
Hexane
P
PG
PG
G
S
Methanol
Acetone
DMF
IS
P
nꢀButanol
Toluene
S
G
a S = solution, P = precipitation, G = gelation, PG = partial gelation, IS = insoluble gelator concentration is 3.0
mg/mL; gels formed at room temperature.
b)
a)
Fig. 4. Selected SEM images of xerogel formed by I in nꢀbutanol: a) scale bar is 5 ꢁm; b) scale bar is 2 ꢁm.
2.4 Absorption and emission properties
The UVꢀvis absorption and fluorescence spectroscopic data in CH2Cl2 (DCM) solution (c = 10ꢀ6
mol Lꢀ1) and in the solid state of compound I are shown in Fig. 5. This compound shows the
maximum absorption peak at 403 nm in DCM solution which may be attributed to the πꢀπ*
transition. The red shift (of about 7 nm in the solid state) suggests the formation of πꢀstacked
aggregates with a Jꢀtype parallel stacking mode in the solid state.44 The photoluminescence (PL)
spectrum in the solid state exhibits a blue shifted emission with maxima at 523 nm, while the
solution displays a structured emission with a maximum at 535 nm. Hence the Stokes shift has a
remarkably large value of 132 and 113 nm in DCM solution and in the solid state respectively.
Compound 4 (Scheme 1) with methoxy groups replacing the triazole and trialkoxylbenzene units
has the maximum absorption peak at 409 nm and maximum emission at 542 nm (DCM, c = 10ꢀ6
mol Lꢀ1), respectively.11 Both, the absorption maxima and the emission peaks of compounds I and 4
are very similar, indicating that for both compounds the DBTD core acts as chromophore and that
the triazole rings and the trialkoxylbenzyl units in compound I do not contribute to π conjugation of
the DBTD core.
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a) 1.2
1.0
b)
403nm
535nm
410nm
523nm
in DCM
Film
0.8
0.6
0.4
0.2
0.0
350
400
450
500
/nm
550
600
650
λ
Fig. 5. a) Normalized spectra and emission spectra of I (10ꢀ6M) at 20 °C; b) Fluorescence images of I in hexane,
toluene, THF, and DCM (from left to right).
The energy band gap of compound I, which was estimated from the onset of the absorption in
thin film, is about 2.67 eV.45 The HOMO and LUMO energy levels of I in thin films were
determined by cyclic voltammetry on a glassy carbon electrode (Fig. S3 and Table S2 in the
Supporting Information) from the onset of oxidative or reductive potentials and the band gap is
calculated to be 2.44 eV. Consequently, the bandꢀgap was almost in agreement with those obtained
from their absorption spectra in thin films. In order to investigate the conformation and electron
distributions of I, calculations based on density functional theory (DFT) with the Gaussian 03W
program package at B3LYP/(6ꢀ31G, d) level were performed with the model compound I, having
methoxy groups instead of the OC16H33 chains. The electron distributions of the HOMO and
LUMO of I are shown in Fig. 6. In the minimum energy conformation compound I adopts almost a
boat shaped conformation with kinks provided by the CH2 groups, linking the peripheral phenyl
groups to the triazoles. As it can be seen in the HOMO orbital, the electrons are localized on the
phenyl rings and the benzothiadiazole unit of the central πꢀconjugated DBTD core, in the LUMO
orbital, the electrons are mainly localized on the benzothiadiazole unit, resuming that
intramolecular charge transfer (ICT) exists in the I molecules.
a)
b)
Fig. 6. a) HOMO orbital; b) LUMO orbital of I/1 (calculated using the DFT/B3LYP, 6ꢀ31G, d functional).
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a)
b)
1.2
1.0
0.8
0.6
0.4
0.2
0.0
527nm
Hexane
Toluene
THF
519nm
408nm
DCM
THF
Toluene
Hexane
409nm
411nm
535nm
508nm
403nm
1.0
0.5
0.0
DCM
400
480
450
500
550
/nm
600
650
λ
λ
/nm
Fig. 7. a) UVꢀvis spectra of I (10ꢀ6M) at 20 °C in hexane, toluene, THF, DCM; b) Fluorescence spectra of I in
hexane, toluene, THF, DCM excited at 412 nm, 409 nm, 408 nm, 403 nm respectively.
Table 2 Fluorescence and excitation data of I (10ꢀ6M) at 20°C, where λex is the excitation maximum, λem is the
fluorescence emission maximum, and ꢂλST is the Stokes shifta
Compd.
Solvent
DCM
λexc
λem
ꢂλST
ФFL
403 nm
535 nm
132 nm
0.50
Chloroform
THF
407 nm
408 nm
409 nm
411nm
410 nm
539 nm
527 nm
519 nm
508 nm
523 nm
132 nm
119 nm
110nm
97 nm
0.55
0.61
0.58
0.53
ꢀb
I
Toluene
Hexane
film
113 nm
a The Stokes shift was obtained from the difference of the emission and absorption maximum (ꢂλST = λem ꢀ λex) ; b not
measured.
For further investigation of the influence of solvent polarity on the optical properties of the
benzothiadiazole derivative I, the UVꢀvis and fluorescence spectra were measured in various
solvents (see Fig. 7 and Table 2). The maxima of the absorption peaks are only slightly red shifted
with increasing solvent polarity and the emission bands are shifted to longer wavelengths with an
increase in the solvent polarity, from 508 nm (hexane) to 519 nm (toluene) to 527 nm (THF).46
Furthermore, fluorescence quantum yields (ФFL) of compound I in the above solvents were
determined relative to quinine sulfate in sulfuric acid aqueous solution and calculated according to
the literature (see Table 2).47 The highest ФFL value (0.61) is achieved in the polar solvent THF. It
seems that the polar solvent media causes a disturbance of the solvation quenching because in the
polarized excited state, the positive charge may be delocalized among the donor moieties48
Compared to the methoxy substituted compound 4 (ФFL = 0.78 in DCM), the ФFL value of the new
compound I (ФFL = 0.50 in DCM) is slightly lower, but it still keeps a high quantum yield.
2.5 Chemosensor behavior
To get insights into the binding properties of compound I toward metal ions, the fluorescence
profiles of I in the presence of 30 equiv of selected cations in different solutions were investigated.
In the solution of CH3CN : DCM = 2 : 1 (Fig. 8c,d), the fluorescence emission was significantly
8

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quenched by Cu2+, as already observed in some triazole containing compounds.49 The fluorescence
quenching decreases in the sequence Cu2+, Ca2+, Ba2+, Co2+, Na+, Mg2+, Cr3+, Cd2+, Zn2+, Li+, Ni2+,
Ag+, K+ (Fig. 8c,d). However in the solution of DMSO : DCM = 2 : 1, the fluorescence emission
was significantly quenched by Li+, in this case the sequence is very different and the fluorescence
quenching decreases in the sequence Li+, Ag+, Cd2+, Co2+, Cu2+, Fe3+, Hg2+, Cr3+, Al3+, Pb2+, Ni2+,
Ca2+, Mg2+, Ba2+ from high to low (Fig. 8a,b). Therefore, the selectivity of compound I toward
different metal ions could be varied depending on the type of solvents, namely the binding
selectivity among a series of cations could be controlled by changing the type of solvent. The result
also shows an interesting finding that for charge dense ions, such as Mg2+, Ca2+ and Ba2+ in
CH3CN : DCM = 2 : 1, the binding selectivity is ranked in the top region, but in DMSO : DCM = 2 :
1, the binding selectivity of these charge dense ions is the lowest. The possible reason is that
DMSO can provide additional hydrogen bonding with the binding sites in the structure of
compound I (the triazole unit) while CH3CN as solvent does not;37 this may make the difference in
selectivity among the series of cations in different solvents. Compared with the previously reported
BTD derivatives, in which triazoles were anchored directly on the BTD core,32c,k,l,37 the highest
cation selective fluorescence quenching efficiency of compound I (53.6 % ) is slightly weaker than
those of the reported BTD derivatives (almost 73 %).
a)
b)
blank
Cd2+
Co2+
Cu2+
Pb2+
Al3+
2500
2000
1500
1000
500
40
20
0
Li+
Hg2+
Fe3+
Cr3+
Ag+
Ni2+
Mg2+
Ca2+
Ba2+
0
450
500
550
600
650
700
λ
/nm
c)
d)
5000
4000
3000
2000
1000
0
30
blank
Zn2+
Cd2+
Co2+
Cu2+
Cr3+
Na+
20
10
0
K+
Ni2+
Ag+
Li+
Mg2+
Ca2+
Ba2+
500
600
A
700
Fig. 8. Fluorescence spectra of compound I (10ꢀ6 M) at room temperature upon addition of various metal cations (30
equiv, except for K+ , Ca2+, Ba2+ and Mg2+ the counter anion are Cl−, for other cations, the counter anions are
ꢀ
ClO4 ): a,b) in DMSO : DCM = 2 : 1 (λex = 423 nm) and c,d) in MeCN:CH2Cl2 (2:1) (V/V) (λex = 398 nm),;
(F0ꢀF)/F0×100 depicts
the cation selective fluorescence quenching efficiency of compound I namely the
fluorescence responses of different metal ions; abbreviation: F0 = the fluorescence emission maximum of blank
sample; F = the fluorescence the fluorescence emission maximum of samples with addition of different metal ions.
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For the selective response of I to Li+, spectral titration was performed in solution of DMSO :
DCM = 2 : 1; with the addition of Li+ (from 0.5 to 30 equiv), the emission peak at 542 nm
decreased gradually and finally reached its fluorescence quenching plateau at ~ 9 equiv (Fig.
9).32c,50 Although the triazoles are not in conjugation with the 4,7ꢀdiphenylꢀ3,2,1ꢀbenzothiadiazole
unit (CH2 group interrupts the conjugation), compound I can still have long excitation and emission
wavelength while keeping a high fluorescence quantum yield. Therefore, compound I could be
used as chemosensor exhibiting strong and selective binding to Li+ in the solution of DMSO : DCM
= 2 : 1.
a)
b)200000
2400
2000
1600
1200
800
400
0
blank
0.5
1.0
1.5
2.0
2.5
3.0
6.0
8.0
15
150000
100000
50000
30
0
100
Concentration
200
300
450
500
550
600
650
700
6
×
10- (mol/L)
λ
/nm
Fig. 9. a, b) Fluorescence spectra of compound I (3.33×10ꢀ6 M) at 20 °C upon addition of Li+ (from 0.50 to 27
equiv) in DMSO : DCM = 2 : 1 (λex = 423 nm).
3. Conclusion
A new fluorescent polycatenar liquid crystal I containing a 4,7ꢀdiphenylꢀ2,1,3ꢀbenzothiadiazole
core and three alkoxy chains at each terminal was designed and synthesized. This compound can
selfꢀassemble into a liquid crystalline oblique columnar phase in its pure state and forms
fluorescent organogels in different organic solvents. At the same time, it shows intense fluorescent
emission with large Stokes shift in solution and has good binding selectivity to Li+ among a series
of cations in DMSOꢀDCM solution. Compared with the reported BTD derivatives in which
triazoles were anchored directly on the BTD core,32c,k,l,37 the presence of the methylene units
between BTD and the triazole rings in this compound does not have a negative impact on the
photoꢀelectronic properties and this compound still has a high fluorescence quantum yield (ΦF =
0.61 in THF) and a good selectivity to Li+. Thus, this fluorescent compound with low energy band
gap, forming a columnar mesophase structure in the pure state and organogels in solution, could
form macroscopically ordered films both in the pure state and from solution in organic solvents.
This is favorable for FET applications as well as for lowꢀcost deposition or solutionꢀprocessing
techniques for largeꢀarea organic electronics applications.27
Acknowledgements
This work was supported by the National Natural Science Foundation of China [no. 21364017, no. 21274119,
21274132], the Yunnan Natural Science Foundation [no. 2013FA007] and Yunnan Provincial Department of
Education Foundation [no. ZD2015001]. The calculations were performed with the support of the Yunnan University
Supercomputer Center.
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Synthesis and self-assembly of luminescent hexacatenar molecules
incorporating a 4,7-diphenyl-2,1,3-benzothiadiazole core
Danxiang Huang,a Marko Prehm,b Hongfei Gao,a Xiaohong Cheng,a* Yongsong Liu,c*
Carsten Tschierskeb
a
Key Laboratory of Medicinal Chemistry for Natural Resources, Chemistry Department, Yunnan
University, Kunming, Yunnan 650091, P. R. China.
b
Institute of Chemistry, Organic Chemistry, Martin-Luther University Halle-Wittenberg
Kurt-Mothes Str. 2, 06120 Halle/Saale, Germany.
c
Department of Physics, Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China.
A luminescent hexacatenar molecule forms an oblique columnar liquid crystal, gels in various
organic solvents, and has binding selectivity to Li+ in DMSO-CH2Cl2 solution.