First columnar rufigallol liquid crystals with high fluorescence at aggregated states

Article abstract of DOI:10.1016/j.molliq.2019.112074

The design and synthesis of columnar liquid crystals with high fluorescence at aggregated states (eliminating the ACQ effect) was an important challenge in the field of liquid crystalline materials. In this work, the first rufigallol columnar liquid crystals with AIE groups were prepared and exhibited good fluorescence in aggregated states. A series of diphenylacrylonitrile-rufigallol-diphenylacrylonitrile trimers was designed and prepared in 70–78% yields. They showed the ordered hexagonal columnar liquid crystals based on the induction of planar rufigallol structures. They also exhibited the good fluorescence in aggregated states with the fluorescence quantum yields of 0.21–0.26 based on the AIE effect of diphenylacrylonitrile units. The length of bridging alkyl chains between rufigallol and diphenylacrylonitrile units contributed to decrease the mesophase transition temperature and increase the fluorescence quantum yields.

Full text of DOI:10.1016/j.molliq.2019.112074

Journal Pre-proof
First columnar rufigallol liquid crystals with high fluorescence at
aggregated states
Xiaoyi Zhang, Wenwei Qin, Bifeng Cheng, Hongyu Guo, Fafu
Yang
PII:
S0167-7322(19)34385-5
DOI:
https://doi.org/10.1016/j.molliq.2019.112074
MOLLIQ 112074
Reference:
To appear in:
Journal of Molecular Liquids
Received date:
Revised date:
Accepted date:
4 August 2019
2 November 2019
4 November 2019
Please cite this article as: X. Zhang, W. Qin, B. Cheng, et al., First columnar rufigallol
liquid crystals with high fluorescence at aggregated states, Journal of Molecular
Liquids(2019), https://doi.org/10.1016/j.molliq.2019.112074
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First columnar rufigallol liquid crystals with high fluorescence at aggregated
states
1
,2
1
1
1*
1,3*
Xiaoyi Zhang , Wenwei Qin , Bifeng Cheng , Hongyu Guo , and Fafu Yang
1
College of Chemistry and Materials Science, Fujian Normal University, Fuzhou 350007, P. R. China
Fujian University of Technology, Fuzhou, 350118, China
2
3
Fujian Key Laboratory of Polymer Materials, Fuzhou 350007, P. R. China
*Corresponding author; e-mail: yangfafu@fjnu.edu.cn; Tel.: +0086-591-83465225; fax: +0086-591-83465225
Abstract The design and synthesis of columnar liquid
interests due to the effective combination of
intrinsic luminescent capability and
supramolecular self-assembly characteristic
within mesophase. For example, the
crystals with high fluorescence at aggregated states
(
eliminating the ACQ effect) was an important
challenge in the field of liquid crystalline materials. In
this work, the first rufigallol columnar liquid crystals
with AIE groups were prepared and exhibited good
fluorescence in aggregated states. A series of
diphenylacrylonitrile-rufigallol-diphenylacrylonitrile
trimers was designed and prepared in 70-78% yields.
They showed the ordered hexagonal columnar liquid
crystals based on the induction of planar rufigallol
structures. They also exhibited the good fluorescence
in aggregated states with the fluorescence quantum
yields of 0.21-0.26 based on the AIE effect of
diphenylacrylonitrile units. The length of bridging
a
fluorescence columnar liquid crystals based on
perylene derivatives as aromatic conjugated core
were constructed conveniently [5-15]. However,
the normal luminescent columnar liquid crystals
did not emit fluorescence effectively in
aggregated state due to the aggregation caused
quenching (ACQ) effect, although they possessed
good fluorescence in solution. Recently,
aggregation-induced emission (AIE), which
eliminated the ACQ effectively, had been
successfully applied to construct the fluorescent
liquid crystals [16-25]. Generally, the AIE
molecules are the incomplete coplanar structures,
which are against effective π-π packing in column
msophase, resulting in smectic or nematic
mesophases in most cases. Lately, in order to
obtain the AIE columnar liquid crystal, our
groups reported several AIE columnar liquid
crystals by combining AIE unit and discotic
triphenylene unit within a molecule, which
exhibited not only fluorescence at aggregated
state but also columnar mesophase [26, 27]. Is
this strategy suitable for constructing fluorescence
columnar liquid crystal extensively? In this paper,
the discotic rufigallol unit, which was usually
used for building columnar liquid crystal [28-34],
was firstly bridged with AIE diphenylacrylonitrile
unit. The obtained diphenylacrylonitrile-rufigallol
-diphenylacrylonitrile trimers displayed both
ordered hexagonal columnar liquid crystals and
good fluorescence in aggregated states. Moreover,
the influence of length of bridging chains between
alkyl
chains
between
rufigallol
and
diphenylacrylonitrile units contributed to decrease the
mesophase transition temperature and increase the
fluorescence quantum yields.
Keywords
Rufigallol ·Diphenylacrylonitrile ·Mesophase ·Fluore
scence ·Aggregated state
Introduction
In recent years, columnar liquid crystals were
paid much attention due to their unique π-π
stacking structures with the fast charge carrier
mobility in mesophase [1], displaying the
application prospects on organic field-effect
transistors, organic light-emitting diodes, organic
photovoltaic cells, gas sensors, etc [2-4]. The
luminescent columnar liquid crystal, as the
important part among various liquid crystalline
materials, had attracted considerable research
1

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two structural units on mesomorphic properties
and fluorescence properties were investigated.
This work confirmed again that the strategy of
combining AIE unit and discotic unit within a
molecule is a good method to prepare the
columnar liquid crystal with high fluorescence at
aggregated states.
respectively. The structures of novel trimers 7a-7c
1
were confirmed by the characterizations of H NMR,
13
C NMR, MALDI-TOF-MS and elemental analysis
techniques (see the SI). All spectral and analytic data
were consistent with the molecular structures. For
examples, two singlets and four doublets for the ArH
and C=CH certainly supported the symmetrical
structures of compound 7a-7c.
Result and discussion
Mesomorphic properties
Synthesis and characterization
1
2
0
8
6
4
2
0
CHO
CN
CHO
HO
EtOH, NaOH
C5H11Br
C5H11O
1
cooling
OH
CH3CN, KI, K2CO3
NC
OC5H11
OH
2
second heating
1
Br K CO , MeCN
+
2
3
5
C H11O
Br
2
Br
n
7a
7b
cooling
O
n
NC
3
3
3
a (n = 1)
b (n = 2)
c (n = 5)
second heating
cooling
O
OH
O
O
O
OH
HO
HO
C5H11O
C5H11O
OC5H11
OC5H11
OH
HO
HO
OH C5H11Br
NaOH, DMSO
H2SO4
100 oC, 4h
second heating
OH
OH
OH
O
OH
7c
4
5
6
CN
0
50
100
150
200
250
O
n
OC5H11
o
Temperature ( C)
O
O
O
C5H11O
C5H11O
OC5H11
Figure 1 DSC scanning curves of samples 7a, 7b and
K2CO3, MeCN
7a (n = 1)
3
+
6
7b (n = 2)
7c (n = 5)
o
-1
OC5H11
n
7c (scan rate 10 C min )
O
C5H11O
O
NC
At first, the mesomorphic behaviors of 7a, 7b and 7c
Scheme 1 The synthetic routes of trimers 7a-7c
were examined by differential scanning calorimetry
(
DSC) analysis. The DSC scanning curves was
As the symmetrical structure contributed to columnar
liquid crystal, the symmetrical diphenylacrylonitrile-
rufigallol-diphenylacrylonitrile trimers 7a-7c were
designed as target compounds, in which two
diphenylacrylonitrile units were bridged onto discotic
core of rufigallol by different alkyl spacers and six
pentyl groups were on periphery. On the other hand,
exhibited in Figure 1 and the related data were
summarized in Table 1. Sample 7a displayed the
o
o
endothermic peaks at 71.8 C and 144.1 C on second
o
heating and two exothermic peaks at 59.4 C and
o
129.9 C upon cooling, respectively. Two endothermic
peaks and two exothermic peaks also were observed
o
o
for sample 7b at 57.5 C and 194.2 C during second
o
o
the CH
been confirmed as good spacers for FRET
fluorescence resonance energy transfer) effect [10,
5, 35], so they were chosen here as spacers to
2
CH
2
, CH
2
CH
2
CH
2
, and (CH
2
)
6
linkages had
heating, and at 47.5 C and 173.8 C for cooling
process, respectively. Sample 7c exhibited the similar
o
(
thermic process with the endothermic peaks at 49.6 C
o
1
and 194.1 C on second heating and two exothermic
o
o
investigate the possible FRET effect. The synthetic
routes for compounds 7a-7c were illustrated in
Scheme 1. The diphenylacrylonitrile derivatives 3a-3c
with terminal Br and rufigallol derivative 6 were
prepared according to the reported procedure [36, 37],
respectively. By treating compounds 3a, 3b or 3c with
peaks at 37.4 C and 187.3 C upon cooling. These
results suggested that novel trimers 7a-7c possessed
two phase transitions of solid state-mesophase and
mesophase-isotropic phase for the phase transition
processes during second heating and cooling,
implying the reversible liquid crystallic behavior
during thermal processes. Moreover, it can be seen
that the phase transition temperatures showed the
compound
6
in
2 3
K CO /MeCN system, target
compounds 7a, 7b and 7c were prepared after column
o
o
o
chromatography in yields of 73%, 70 and 78%,
order of 7a (71.8 C) > 7b (57.5 C) > 7c (49.6 C) and
2

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the temperature scopes of liquid crystalline
displayed the typical textures of samples 7a, 7b and
o
o
mesophase exhibited the order of 7a (72.3 C) < 7b
7c at 100 C, which were the typical focal-conic
o
o
(
136.7 C) < 7c (144.5 C) after calculation. These
textures, indicating the hexagonal columnar liquid
crystals.
data suggested the length of bridging alkyl chains
between rufigallol and diphenylacrylonitrile units
played an important role for adjusting the liquid
crystalline behavior. The longer bridging alkyl chains
resulted in the lower mesophase transition
temperature and wider temperature scopes of liquid
crystalline mesophase. On the hand, the broad thermal
peaks and slight hysteresis for cooling peaks could be
attributed to their large molecular weights and the
highly viscous morphology upon melting process.
400
300
200
100
0
d100
d110
d001
d200
d100
d001
d001
7a
7b
d110
d200
d
1
00
10 d200
d
1
7c
1
0
20
30
40
50
o
2
θ (degree)
Table 1 Transition temperatures ( C) and enthalpies
-1
o
(
kJ·mol ) of 7a, 7b and 7c
Figure 3 XRD traces of samples 7a-7c at 100 C.
Comp.
T(ΔH)
T(ΔH)
Cooling scan
59.4(12.6)
129.9(6.8)
47.5(12.5)
173.8(9.2)
37.4(6.1)
[
a]
Phase transition
Heating scan
71.8(16.6)
144.1(2.2)
57.5(13.3)
194.2(10.9)
49.6(17.4)
194.1(3.4)
The molecular stacking behaviors of samples 7a,
7b and 7c at mesophase were further studied by the
XRD analysis as shown in Figure 3. Upon their
7a
Cr-Col(Col-Cr)
Col-Iso(Iso-Col)
Cr-Col(Col-Cr)
Col-Iso(Iso-Col)
Cr-Col(Col-Cr)
Col-Iso(Iso-Col)
o
7b
mesophase at 100 C, samples 7a, 7b and 7c
displayed three obvious reflections in the small-angle
o
o
o
o
o
7c
region at 4.00 , 6.92 , and 8.01 for 7a, 3.95 , 6.85
o
o
o
o
187.3(2.9)
and 7.91 for 7b, and 3.92 , 6.82 and 7.85 for 7c,
respectively. According to the Bragg's formula d =
λ/(2sinθ), these reflections suggested the d-spacings
of 22.07, 12.76, and 11.03 Å for 7a, 22.35, 12.89, and
[
a] Cr=crystalline, Col=columnar phase, Iso=isotropic
1
1.17 Å for 7b, 22.52, 12.95, and 11.25 Å for 7c,
respectively. These distances agreed with the ratios of
: 1/√3:1/√4, indicating strongly the [100], [110] and
1
[
200] planes of hexagonal lattice. Furthermore, in the
o
wide angle region, the broad reflections at 17~28
(
d-spacings of 3.21~5.20 Å) could be ascribed to
Figure 2 Mesomorphic textures of 7a, 7b and 7c
o
signals for liquid-like packing of alkyl chains. The
under POM observations upon cooling at 100 C.
o
o
o
small peaks at 23.80 for 7a, 23.52 for 7b, 23.35 for
(
×400)
7c were observed, suggesting the distances of 3.73,
3.78 and 3.81 Å for the intracolumnar core-to-core
Next, the mesomorphic textures of trimers 7a, 7b
distances of columnar liquid crystals. All these XRD
analysis supported that trimers 7a, 7b and 7c adopted
the ordered hexagonal columnar stacking at
mesophase. Also, the lattice constant (ɑ) was
estimated as 25-26 Å for samples 7a-7c based on the
XRD data. Thus, the number (n) of molecules in a
single disk for the columnar stacking could be
and 7c were investigated by the observation under the
polarizing optical microscopy (POM). When samples
7a, 7b and 7c were heated from the room temperature
to isotropic phase and then cooled to room
temperature again, the phase transition of solid
state-mesophase-isotropic
phase
could
be
distinguished at the corresponding temperatures,
which agreed with the DSC peaks approximately. By
cooling from isotropic phase slowly, the regular
mesomorphic textures emerged gradually. Figure 2
calculated according to the following formula.
2
n = (ɑ )(√3/2)(hρN
A
/M)
A
where the ɑ is the hexagonal lattice parameter, N is
3

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A
0
1
2
Avogadro’s number and M is the molecular mass of
2500
0%
0%
sample. h is the thickness of the slice estimated on the
reflections of wide-angle X-ray traces. The ρ is the
2000
1500
1000
500
0
30%
0%
4
50%
60%
70%
3
density assumed as 1 g/cm . After calculation, the
8
0%
90%
5%
values of n were approximately 1 for samples 7a, 7b
and 7c. Therefore, the proposed molecular stacking
model of the hexagonal columnar mesophase of
samples 7a, 7b and 7c was proposed as Figure 4. On
the other hand, it could be seen that, with the
increasing length of bridging chains, the peak width
became broader with the order of 7a < 7b < 7c. These
phenomena could be explained by that the longer
flexible bridging chains increased the randomness of
orientation of diphenylacrylonitrile units and
decreased the degree of stacking order at mesophase.
9
400
450
500
550
600
wavelength / nm
0.22
B
0.20
0.18
0.16
0.14
0.12
0.10
0.08
Φ
f
95%
0%
2
5-26 angstrom
d110
d100
0
20
40
60
80
100
Water Fraction (vol %)
Figure 6. (A) Fluorescence spectra of sample 7a in
THF-H O mixtures with different fractions of H
CN
O
Self-assembly
O
O
O
O
O
O
O
O
d001
2
-5
2
O
O
O
(1.0×10 M, λ = 340 nm). (B) Plot of values (Ф )
ex
F
O
NC
versus the fractions of H
2
O. The inset graph was
fluorescence pictures in THF solution and THF-H
with 95% of H O under UV365 light.
2
O
Figure 4 The proposed molecular stacking mode of
2
2
2
1
1
500
000
500
000
the hexagonal columnar mesophase.
A
0
1
20%
3
4
50%
0%
0%
0%
Photophysical properties
Diphenylacrylonitrile unit was classic AIE functional
group with excellent emission at aggregated state.
Therefore, the photophysical properties of samples 7a,
6
7
0%
0%
80%
0%
95%
9
5
00
7
b and 7c were measured by UV-vis spectra and
fluorescence spectra. Figure 5 illustrated the UV-vis
absorption spectra of compounds 7a, 7b and 7c in
THF solution, which exhibited the similar absorption
peaks at 280 nm and 340 nm for rufigallol unit and
diphenylacrylonitrile unit, respectively.
0
4
00
450
500
550
600
Wavelength / nm
0
.26
B
0.24
0
0
0
0
.22
.20
.18
.16
Ф
f
0
0
0
0
.15
.10
.05
.00
7a
7b
7c
9
5%
0%
0.14
0.12
0.10
0.08
0
20
40
60
80
100
Water Fraction (vol %)
Figure 7. The fluorescence spectra (A), plot of values
) versus the fractions of H O (B) and fluorescence
2
00
300
Wavelength/nm
400
(
Ф
F
2
pictures of sample 7b. The experimental conditions
Figure
5
The UV-vis absorption spectra of
were the same as those in Figure 6.
-5
compounds 7a, 7b and 7c in THF (1.0×10 M)
4

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2
H O and at solid films were measured and the results
were summarized in Table 2. All of them exhibited
good fluorescence emission at aggregated states. The
A
0
1
2
3
4
5
6
7
%
0%
0%
0%
0%
0%
0%
0%
2
000
000
0
Ф
F
values showed the order of 7a (0.21) < 7b (0.24) <
7c (0.26) in THF-H O solution. The same order of 7a
2
(0.16) < 7b (0.19) < 7c (0.20) was also observed at
solid films. This order might indicate that, with the
increase of flexible alkyl chains between rufigallol
and diphenylacrylonitrile units, the degree of stacking
order decreased at aggregated states, resulting the
lower ACQ effect and higher AIE emission. Also, the
1
80%
9
9
0%
5%
4
00
450
500
550
Wavelength / nm
0
0
0
0
0
.30
B
Ф
F
values at solid films were smaller a little than that
in THF-H O solution, which could be ascribed to the
higher degree of order in solid films than that in
THF-H O solution. All these photophysical studies
.25
.20
.15
.10
2
2
Φ
f
9
5% 0%
implied that trimers 7a, 7b and 7c have excellent
fluorescence emission at aggregated states. The
flexible
spacers
between
rufigallol
and
diphenylacrylonitrile units make important influence
on fluorescence emission. The longer spacers led to
the higher the fluorescence quantum yields. It was
worthy of noting that samples 7a, 7b and 7c were the
first examples of columnar rufigallol liquid crystals
with high fluorescence at aggregated states.
0
20
40
60
80
100
Water Fraction (vol %)
Figure 8. The fluorescence spectra (A), plot of values
) versus the fractions of H O (B) and fluorescence
(
Ф
F
2
pictures of sample 7c. The experimental conditions
were the same as those in Figure 6.
Table 2. Absorption and fluorescence data for
samples 7a-7c at room temperature
Further, the fluorescence properties of samples 7a,
7
a
7b
281, 339
441
7c
282, 340
442
7
b and 7c were investigated in THF-H
2
O solutions.
λabs (nm)
280, 339
440
As shown in Figure 6A, 7A and 8A, the fluorescence
intensities of samples 7a, 7b and 7c were weak in
pure THF solution. However, after the addition of
em
λ (nm)
Stokes shift (nm)
101
102
102
a
F
Ф (solution )
0.21
0.24
0.26
H
2
O in the THF solution, the fluorescence emission
F
Ф (films)
0.16
0.19
0.20
increased gradually. The increase of fluorescence
intensities was slow when the water fractions were
below 70%. When the water fractions were bigger
than 70%, the fluorescence intensities increased
Ф (mesophase)
0.15
0.18
0.17
F
[
a]
2 2
Solution was THF-H O mixture with 95% of H O.
Moreover, the fluorescence behavior for their
o
2 2
rapidly. In the THF-H O mixture with 95% of H O,
mesophase at 100 C were measured and compared
with the fluorescence spectra at room temperature. As
shown in Figures S13-15, the fluorescence intensities
the fluorescence quantum yield also increased
obviously for samples 7a, 7b and 7c than that in THF
solution, respectively (Figure 6B, 7B and 8B). These
fluorescence investigations certainly supported the
strong AIE effect for trimers 7a, 7b and 7c. Moreover,
it can be seen that the maximum fluorescence
f
decreased slightly in mesophase. The Φ values also
decreased a little as listed in Table 2. Nevertheless,
compounds 7a-7c still possessed good fluorescence in
f
mesophase with Ф of 0.15-0.17. The maximum
2
emission exhibited little red shift in THF-H O
fluorescence wavelength exhibited some blue shift by
compared with that at room temperature. In general,
the columnar mesophase possessed stronger the
ordered π-π stacking, resulting in the stronger ACQ
soluitons, suggesting the J-aggregation in the
aggregated states. On the other hand, the fluorescence
2
quantum yields in THF-H O mixture with 95% of
5

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effect and lower fluorescence intensity than that in
surrounding by six flexible alkyl chains was designed
and synthesized in 70-78% yields. Studies on their
liquid crystalline properties suggested their ordered
hexagonal columnar liquid crystals at mesophase due
to the effective induction of planar rufigallol
structures. The longer bridging alkyl chains between
rufigallol and diphenylacrylonitrile units resulted in
the lower mesophase transition temperature and wider
temperature scopes of liquid crystalline mesophase.
The investigation on photophysical properties
confirmed their excellent AIE fluorescence emission.
The fluorescence quantum yields in aggregated states
were 0.21-0.26 with the maximum emission
wavelength of 440 nm. The length of bridging alkyl
chains between rufigallol and diphenylacrylonitrile
units was favorable for increasing the fluorescence
quantum yields. This work was the first columnar
rufigallol liquid crystals with excellent fluorescence at
aggregated states, confirming again that the method of
combining AIE unit and discotic unit within a
molecule is good strategy for design and synthesis of
novel columnar liquid crystal with high fluorescence.
solid state. Thus, all these photophysical properties in
mesophase might be explained that, in their columnar
msophases, the ordered columnar π-π stacking was
favorable for H-aggregation, resulting in the blue shift
of fluorescence and some ACQ effect in compared
with the unordered molecular stacking in solid films.
On the other hand, in order to confirm the AIE
effect based on diphenylacrylonitrile unit further, the
fluorescence spectra excited at 280 nm for rufigallol
units were also investigated. The results indicated
compounds 7a, 7b and 7c had strong fluorescence at
3
13 nm in pure THF solution (as shown in Figure
S10-12). However, with the increase of water
fractions in THF-H O solution, the fluorescence
decreased gradually and the fluorescence almost
quenched completely in THF-H O solution with 95%
of H O. Moreover, the contrast of UV-vis spectra and
2
2
2
fluorescence spectra of 3a, 6 and 7a were in Figure
S16 and S17 (using 7a as representative for
investigation). By comparing with the absorption
peaks, it can be seen that the absorption at 260-300
nm and 320-380 nm were attributed to the absorption
of rufigallol and diphenylacryronitrile unit,
respectively (Figure S16). Also, by comparing with
Experimental
the emission peaks, the emission at 400-480 nm (λex
40 nm) of sample 7a was ascribed to the emission of
diphenylacryronitrile unit (Figure S17). By emitting at
ex = 280 nm, 7a showed no emission at 400-480 nm
=
Material and Method
3
All chemical reagents were obtained from commercial
suppliers. The organic solvents were purified by the
standard anhydrous methods before use. TLC analysis
was carried out on pre-coated glass plates. Column
chromatography was done by using silica gel
(200-300 mesh) as absorbent. NMR spectra were
λ
and the emission at 300-350 nm was attributed to
rufigallol units (Figure S10). All these results implied
the strong ACQ effect for the fluorescence excited at
o
280 nm based on the absorption of rufigallol units,
examined on a Bruker-ARX 400 instrument at 25 C.
and no FRET effect between rufigallol unit and
diphenylacrylonitrile unit happened although the
absorption peak of diphenylacrylonitrile unit (300-400
nm) was overlapped with the emission peak of
rufigallol unit (300-350 nm) in some degree. These
results also further confirmed that the strong
fluorescence of compounds 7a, 7b and 7c at
aggregated states were attributed to the AIE effect of
diphenylacrylonitrile unit.
Chemical shifts were recorded in ppm with internal
standard of tetramethylsilane (TMS). MS spectra were
measured on Bruker MALDI-TOF mass spectrometer.
The phase transitions were studied by POM (Leica
DMRX) with a hot stage (Linkam THMSE 600).
Thermal analysis was investigated on DSC (Thermal
o
Analysis Q100) at a scanning rate of 10 C/min under
2
N atmosphere. XRD experiments were done on
SEIFERT-FPM (XRD7) with Cu Kα 1.5406 Å as the
radiation source with 40 kV, 30 mA power. UV-Vis
spectra were obtained on Varian spectrometer.
Fluorescence spectra were performed on a Hitachi
Conclusion
In conclusion, a series of diphenylacrylonitrile
F-4500 spectrometer. The fluorescence absolute Φ
F
-
rufigallol-diphenylacrylonitrile
trimers
7a-7c
values were obtained on an Edinburgh Instruments
6

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FLS920 Fluorescence Spectrometer with a 6-inch
28.82, 28.13, 22.67, 22.42, 14.28. HR-ESI-MS Calcd.
integrating sphere. Compounds 3a-3c were
synthesized by the reported procedures [36].
Compound 6 was prepared by the published
procedure [37].
for (C80
H
98
N
2
O
12) m/z = 1279.6403, found: m/z =
+
1302.2503 (MNa ). Elemental Analysis Calcd.: C
75.09, H 7.72, N 2.19%. Found: C 75.05, H 7.68, N
2.15%.
1
Compound 7c: H NMR (400 MHz, CDCl
3
) δ:
The Synthetic procedure for compounds 7a-7c
7.83(d, J = 8.0 Hz, 4H, ArH), 7.34 (s, 2H, CH), 7.28
(d, J = 8.0 Hz, 4H, ArH), 7.18 (s, 2H, ArH), 7.16 (d, J
= 8.0 Hz, 4H, ArH), 6.72 ((d, J = 8.0 Hz, 4H, ArH),
Under the protection of N
compound 3a (3b or 3c, 1.2 mmol), compound 6
0.29 g, 0.5 mmol) and K CO (0.7 g, 5.0 mmol) was
refluxed and stirred in 30 mL of dried acetonitrile for
4 h. The reaction process was detected by TLC
analysis. After reaction, 30 mL of HCl solution (1 M)
and 60 mL of CHCl were added into reaction system
with violent stirring. Then the CHCl layer was
separated, dried by MgSO and concentrated. The
residue was purified by column chromatography
eluent: CH Cl : hexane = 4 : 1). Compounds 7a, 7b
2
atmosphere, a mixture of
(
2
3
3.90-4.17 (m, 20H, OCH
2
), 0.88-2.01 (m, 70H, CH
2
1
3
and CH
3
). C NMR (100 MHz, CDCl ) δppm: 181.11,
3
2
160.69, 160.33, 159.60, 157.48, 146.97, 142.75,
139.74, 131.52, 131.01, 130.15, 126.94, 118.57,
114.95, 114.88, 114.41, 111.08, 107.93, 74.46, 74.06,
69.12, 68.03, 62.60, 32.75, 30.28, 30.06, 29.73, 29.20,
28.87, 28.82, 28.17, 26.03, 25.89, 25.62, 22.43, 14.05.
3
3
4
110 2 12
HR-ESI-MS Calcd. for (C86H N O ) m/z =
+
(
2
2
1363.7998, found: m/z = 1402.3230 (MK ). Elemental
Analysis Calcd.: C 75.74, H 8.13, N 2.05%. Found: C
75.71, H 8.10, N 2.02%.
and 7c were obtained as a light yellow solid in yield
of 73%, 70% and 78%, respectively.
1
Compound 7a: H NMR (400 MHz, CDCl
3
) δ:
Acknowledgment Financial support from the
7
.84(d, J = 8.0 Hz, 4H, ArH), 7.42 (s, 2H, CH), 7.35
d, J = 8.0 Hz, 4H, ArH), 7.21 (s, 2H, ArH), 7.14 (d, J
8.0 Hz, 4H, ArH), 6.73 ((d, J = 8.0 Hz, 4H, ArH),
.48 (bs, 4H, OCH ), 4.37 (bs, 4H, OCH ), 4.18 (t, J
), 4.02 (t, J = 8.0 Hz, 4H, OCH ),
), 0.88-1.90(m, 54H,
). C NMR (100 MHz, CDCl ) δppm:
National Natural Science Foundation of China (No:
(
21406036), Fujian Science and Technology Project
=
(
No. 2019N0010), Fuzhou science and technology
4
2
2
project (2018-G-44), and Undergraduate innovation
program of FJNU (2020) were greatly acknowledged.
=
8.0 Hz, 4H, OCH
2
2
3.93 (t, J = 8.0 Hz, 4H, OCH
2
1
3
CH
2
and CH
3
3
References
1
1
1
6
2
82.31, 160.87, 160.37, 158.88, 154.93, 143.13,
42.94, 140.28, 131.46, 131.02, 127.11, 126.17,
20.86, 115.16, 114.84, 114.46, 110.92, 69.39, 68.20,
8.10, 66.62, 66.55, 31.94, 30.21, 30.00, 29.85, 29.29,
8.82, 28.06, 22.78, 22.52, 14.09. HR-ESI-MS Calcd.
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30.21, 127.04, 121.08, 114.92, 114.60, 114.42,
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The authors declared that there is no Conflict
of Interest for this paper entitled “First
columnar rufigallol liquid crystals with high
fluorescence at aggregated states (Authors:
Xiaoyi Zhang, Wenwei Qin, Bifeng Cheng,
Hongyu Guo and Fafu Yang)”, which was
submitted to Journal of Molecular Liquids
(
MOLLIQ_2019_4213).
10

Journal Pre-proof
The first AIE diphenylacrylonitrile-modified
rufigallol derivatives were synthesized.
They exhibited good fluorescence in aggregated
states.
They showed the ordered hexagonal columnar
liquid crystals.
The longer bridging spacers, the lower mesophase
F
transition temperature and the higher Ф .
This work is good example of preparing novel
columnar liquid crystal with high fluorescence.
11