New thermally stable cyano-substituted D-A-π-A-D molecules with aggregation-induced emission and large two-photo absorption cross-sections

Article abstract of DOI:10.1039/c2ra22464j

In this work, we have designed and synthesized a series of aggregation-induced emission active compounds (4a-c) via Suzuki coupling reaction. Their one and two-photon absorption properties have been investigated. These compounds exhibit high thermal stability, losing only 5% of their weights when heated to 482-503 °C in air. All compounds are quite weakly fluorescent in THF, while a significant AIE effect is observed in water/THF (v/v 70%/30%) mixtures with a sharp increase in fluorescence intensity (about 86, 42, and 103 times, orange, deep yellow and green, respectively). The solid fluorescence of 4a-c is located at 590, 579 and 547 nm, and their Φ_F values are determined to be 9.2%, 2.4%, and 14.5%, respectively. Besides, the two-photon absorption (2PA) cross-sections of 4a-c were also measured by open aperture Z-scan technique, at the wavelength of 800 nm. The excellent aggregation-induced emission and 2PA cross-sections properties of 4a-c promote them as attractive candidates for biophotonic materials.

Full text of DOI:10.1039/c2ra22464j

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New thermally stable cyano-substituted D–A–p–A–D
molecules with aggregation-induced emission and
large two-photo absorption cross-sections3
Cite this: RSC Advances, 2013, 3,
3038
Wei Huang,a Haitao Zhou,a Bo Lib and Jianhua Su*a
In this work, we have designed and synthesized a series of aggregation-induced emission active
compounds (4a–c) via Suzuki coupling reaction. Their one and two-photon absorption properties have
been investigated. These compounds exhibit high thermal stability, losing only 5% of their weights when
heated to 482–503 uC in air. All compounds are quite weakly fluorescent in THF, while a significant AIE
effect is observed in water/THF (v/v 70%/30%) mixtures with a sharp increase in fluorescence intensity
(about 86, 42, and 103 times, orange, deep yellow and green, respectively). The solid fluorescence of 4a–c
is located at 590, 579 and 547 nm, and their WF values are determined to be 9.2%, 2.4%, and 14.5%,
respectively. Besides, the two-photon absorption (2PA) cross-sections of 4a–c were also measured by open
aperture Z-scan technique, at the wavelength of 800 nm. The excellent aggregation-induced emission and
2PA cross-sections properties of 4a–c promote them as attractive candidates for biophotonic materials.
Received 10th October 2012,
Accepted 17th December 2012
DOI: 10.1039/c2ra22464j
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cence quenching in aggregation. They found that this
phenomenon was caused by restricted intramolecular vibra-
Introduction
tional and rotational motions in the aggregated solid.9 Ning
and co-workers also reported a new class of aggregation-
induced emission enhancement (AIEE) compounds based on
cyclopentadiene derivatives combined with different aryl
groups.10 Profited from these works, some new 2PA dyes were
synthesized both with large two-photo activity and high
fluorescence quantum yields in the aggregation. Prasad and
co-workers have synthesized a dye with aggregation-enhanced
fluorescence and two-photon absorption in nano-aggregates
due to the hindering of molecular internal rotation.11 Tang
also discovered luminogenic molecules and polymers of AIE
and 2PA based on tetraphenylethene.12
Organic molecules with large two-photon absorption (2PA) are
of great interest in the field of materials science due to their
various applications such as optical limiting1, up-converted
lasing2 and microfabrication3. With the wonderful potential
application, a series of compounds with large 2PA cross
sections (s) and good processabilities have been developed.
The molecular designs include symmetrical donor–acceptor–
donor (D–A-D), donor–p-bridge–acceptor (D–p–A), and donor–
p-bridge–donor (D–p–D) structure. These studies show that the
intramolecular charge transfer from the donor groups to the
p-bridge4 can improve the 2PA cross sections. Other factors
such as solvent polarity,5 molecular coplanarity, and hydrogen-
bonding can also enhance the 2PA cross section.6
For the good electron-donating and transporting capabil-
ities, as well as their special propeller starburst molecular
structure, triphenylamine and carbazole have been widely
used in opto- and electroactive materials.13 Recently, 2PA
materials with triarylamine as the electron donor have aroused
great interest and become the focus of intensive research in
this field.14 Moreover, cyano-substituted compounds show
good optical and electrical properties due to their high
electron affinities. Molecules including an electron-withdraw-
ing cyano group on the central phenylene ring exhibits strong
fluorescence and higher 2PA cross section values.15 Some
cyano-substituted compounds have been reported to show
unique enhanced emission rather than a fluorescence quench-
ing in the solid state,16 which enlightened us to design novel
functional molecules with both AIE and 2PA properties. In this
work, three new type D–A–p–A-D molecules (4a–c) (Scheme 1),
However, highly efficient 2PA fluorophores have suffered
the defect of low fluorescence efficiency in aqueous media
because most 2PA molecules are soluble in organic solvents
such as dichloromethane and THF, but lose their fluorescence
in aqueous media, due to self-aggregation driven by limited
solubility as well as p–p interactions.7 Tang and co-workers
recently found an exciting phenomenon termed as aggrega-
tion-induced emission (AIE),8 which could overcome fluores-
aKey Laboratory for Advanced Materials and Institute of Fine Chemicals, East China
University of Science and Technology, Shanghai, 200237, P. R. China.
E-mail: bbsjh@ecust.edu.cn; Fax: (+86) 21-64252288
bKey Laboratory of Polar Materials and Devices, Ministry of Education, East China
Normal University, Shanghai, 200241, P. R. China
Electronic supplementary information (ESI) available. See DOI: 10.1039/
3
c2ra22464j
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Scheme 2 Synthetic route of compounds 4a–c.
coupling reaction in high yield, the key intermediate com-
pounds, bis(4-(diphenylamino)phenyl)methanone (2a) and
bis(4-(9H-carbazol-9-yl)phenyl)methanone (2b) were synthe-
sized according to the literature of Xu.17 The final compounds
4a–c were synthesized by Suzuki coupling reaction between
2a–b and its boron compounds in the presence of a palladium
catalyst. All of the final compounds were confirmed by proton
and carbon nuclear magnetic resonance spectroscopy (1H
NMR, 13C NMR) and high-resolution mass spectroscopy (MS).
Thermal stability
Since compounds 4a–c possess many aromatic rings, they may
show high resistance to thermolysis.18 Fig. 1 shows the TGA
thermograms, compounds 4a–c lost 5% of their weight (Td) at
482–503 uC in air, exhibiting a higher thermostability than
those common materials reported in the literature.
Normalized absorption
One-photon absorption of dyes 4a–c in THF is shown in Fig. 2.
The absorption maxima (lmax) of 4a–c are located at 397 nm,
Scheme 1 Molecular structure of 4a–c.
with diphenylamine and carbazole groups as electron-donat-
ing, 2,2’-(biphenyl-4, 4’-diyl)diacetonitrile as conjugation
bridges, were synthesized. It could be expected that dyes with
multi-electron-donating end-cappers and cyano acceptor
groups should have good 2PA values, as well as AIE properties.
Result and discussion
Synthesis
The synthetic route of three compounds 4a–c is depicted in
Scheme 2. All of the three molecules were prepared by Suzuki
Fig. 1 Thermograms of compounds 4a–c in air.
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Fig. 2 Normalized absorption of 4a–c in THF.
386 nm and 363 nm, respectively. It is clearly shown that the
lmax of 4a is red shifted by 11 nm and 34 nm than 4b and 4c,
which is agreed with the order of the increase of electron-
donating ability of the donors: diphenylamine . carbazole.
AIE properties
Fig. 3 a), b), c) PL spectra of 4a–c, respectively, in THF/water mixtures. d), e), f)
Plots of PL peak intensity versus water content of the solvent mixture for 4a–c.
The compounds are soluble in common organic solvents such
as THF, dichloromethane, but insoluble in water. All the
samples of nano-aggregates of 4a–c were prepared by the
precipitation method, using THF as soluble solvent and water
as insoluble solvent. Fig. 3 shows the corresponding emission
spectra of 4a–c at a concentration of 1 6 1025 M. The
emissions of 4a–c in THF were weak and almost without
photoluminescence (PL).
However, a dramatic enhancement of orange, deep yellow
and green luminescence, respectively, was observed in the
40 : 60 (v/v) water/THF mixtures. The fluorescence reached to
its peak when the water ratio reached 70%. Moreover, a red-
shift in absorption was detected for each of these three
compounds (Fig. 4). Since the hydrophobic nature of target
molecules 4a–c could induce the aggregation with the
increasing ratio of water in solvent, the fluorescence enhance-
ment phenomena could be thus attributed to AIE effect.
Therefore, all three compounds 4a–c were characterized as
AIE-active.
water faction was above 30%, the molecules started to
aggregate. Similar phenomena were probed on the other
compounds 4b–c.
As shown in Fig. 3, the PL intensity was at its peak when the
water ratio was 70%. However, the PL intensity started to fall
down at the water ratio of 80%. A further increase in the water
fraction resulted in a further decrease of PL intensity. This
phenomenon is commonly observed in some compounds with
AIE properties. This is probably due to the variation in the
Through the measurements by the change of the fluores-
cence quantum yield (WF) with adding water, a quantitative
picture of the AIE process can be made. Nonetheless, the Mie
effect of the nano-aggregate in the mixture of the solvent could
make the WF determination inaccurate.19 So we estimated the
integrands of the PL spectra (shown in Fig. 3 d–f) to make the
comparison. For example, no PL intensity was observed in THF
solution of 4a and almost no changes occurred in the mixture
solution with water ratio of 0–30%. However, when the ratio of
water reached 40%, I/I0 began to increase and reached the
maximum upon addition of water ratio to 70% (Fig. 3d). Nearly
86 fold increase (42 fold and 103 fold for 4b–c, respectively) in
I/I0 ratio was achieved at a water fraction of 70% (v/v)
compared to anhydrous THF solution. It is clear when the
Fig. 4 a), b), c) The absorptions of 4a–c in THF and THF/water of 30 : 70 (v/v) at
concentrations of 1 6 1025 M.
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Fig. 7 a) The solid powder emission spectra of 4a–c. b) The thin film emission
spectra of 4a–c.
Such an AIE property was also confirmed by the vivid image
of solid powders, as depicted in Fig. 6. The solid powders were
made by recrystallization and all the compounds emitted
intensely as aggregated solid powders. To quantitatively
evaluate the AIE effect of the fluorescent materials, the
emission spectra and quantum efficiencies (WF) of the solid
powders were measured. Compounds 4a–c exhibits peak
emissions at 590, 579 and 547 nm, respectively. The WF values
are determined to be 9.2%, 2.4%, and 14.5% for 4a–c,
respectively (Fig. 7a). To compare with the amorphous
particles, a thin film was prepared by spin-coating solutions
of the dyes in THF onto quartz.21 Fig. 7b shows the film
emission spectra of 4a–c, which displays an emission with the
maximum at 581, 569 and 543 nm, respectively. The emission
of film is
a little blue-shifted, which agrees with the
phenomenon observed in mixed solvent (Fig. 3a–c).
Fig. 5 a), b), c) SEM images of 4a–c nano-aggregates prepared in THF/H2O
(3 : 7 v/v) and d), e), f) prepared in THF/H2O (2 : 8 v/v) at concentrations of 1 6
1025 M.
packing mode of the dye molecules in the aggregates. When
water is added, the solute molecules can aggregate into two
kinds of nanoparticle suspensions: crystal particles and
amorphous particles.20 Fig. 5 depicts the scanning electron
microscopy (SEM) images of different aggregate forms of 4a–c
in the mixture solution of different water ratios. The 4a–c in
the solution of the 70% (v/v) water/THF mixture aggregated
into crystal nanoparticles, while in the solution of the 80% (v/
v) water/THF mixture the molecules aggregated into amor-
phous nanoparticles. The measured overall PL intensity
depended on the combined actions of the two kinds of
nanoparticles and the formation of nanoparticles was hard to
control in high water content, thus resulting in an irregular
display in the photoluminescent intensity.
Fig. 8 a), b), c) Open-aperture Z-scan trace of 4a–c (scattered circles =
experimental data, straight line = theoretical fitted data). d), e), f) At 800 nm
excited, the TPF emission spectra of 4a–c in the solution 70% : 30% (v/v water/
THF) at a concentration of 1 6 1025 M.
Fig. 6 a), b), c) The images of 4a–c as solid powders under 365 nm UV light
illumination.
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Table 1 Electrochemical and optical properties of 4a–ca
Compound Eonset-ox (V) HOMO (eV) lonset (nm) Eg (eV) LUMO (eV)
4a
4b
4c
0.92
1.04
0.96
25.18
25.30
25.22
482
474
432
2.57
2.61
2.87
22.61
22.96
22.35
a
Abbreviation: Eonset-ox= onset oxidation potential measured by cyclic
voltammetry, HOMO = highest occupied molecular orbital derived by
the equation: HOMO= 2(Eonset-ox + 4.8 2 Eferrocene) eV,23 where the
value of Eferrocene measured in our experiment is 0.54 eV , lonset
=
onset absorption wavelength, Eg = energy band gap determined form
lonset, LUMO = lowest unoccupied molecular orbital = Eg + HOMO.
The compounds of 4a–c in a mixture of water and THF emit
intense fluorescence with the peaks located at 611 nm, 600 nm
and 590 nm, under the excitation of 80 fs, 800 nm pulse
(Fig. 8d–f). Compared with Fig. 3a–c, the good overlap between
one-and two-photon excitation fluorescence indicates that the
emissions resulted from the same excited state, regardless of
the different mode of excitation. Fig. 9a–c shows the two-
photon emission images in different solution. Each of the
compounds 4a–c irradiates orange, deep yellow and green
light with their nano-aggregates suspending in water/THF
mixture solution (70% : 30%), while no emission is observed
in pure THF, when excited with near-IR light of 800 nm to
absorb two photons. As for the limitation of our laser
apparatus, only irradiation at one wavelength of 800 nm was
used to carry out the two-photon excitation experiment. The
2PA cross section for the 4a–c would be better in other
wavelengths.
Fig. 9 a), b), c) The TPF emission images of 4a–c, respectively, in the ratio of
70% : 30% water/THF and pure THF. d), e), f) The OPF emission photos of 1 6
1025 M 4a–c in the water/THF mixtures with 0% and 70% water concentration.
Electrochemical properties
We also investigated the electrochemical properties of 4a–c by
cyclic voltammetry. The energy level parameters of the 4a–c are
Two-photon absorption properties
The 2PA cross sections of 4a–c were tested according to a
previously described method,22 through the femtosecond
open-aperture Z-scan technique (Fig. 8). The 2PA cross section
s can be calculated by the equation of s = hnb/N0, in which N0
= NAC is the number density of the absorption centres, NA is
the Avogadro constant and C represents the solute molar
concentration. The values of the 2PA cross section (s) for 4a–c
are 511 GM, 257 GM and 180 GM, respectively, at the
wavelength of 800 nm. On account of the extended p system
and enhanced intramolecular charge transfer (ICT) from the
triarylamine to the cyano group, the 4a–c show good 2PA
properties. The s values of 4a–c follow the order of 4a . 4b .
4c, owing to the electron-donating strength difference between
donor groups (diphenylamine . carbazole). The results proved
that the strategy of increasing the ICT effect between the
electron donor and acceptor is an effective approach for
enhancing the 2PA cross sections of the molecules. Therefore,
the value of the 2PA cross section to the functional materials
can be modulated by simply introducing different donors or
acceptors.
Fig. 10 Cyclic voltammograms of 4a–c in THF with 0.1 M of tetrabutylmmonium
hexafluorophosphate (nBu4NPF6).
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listed in Table 1. The cyclic voltammetry (CV) of 4a–c was
measured in THF (0.1 M n-Bu4NPF6 as supporting electrolyte),
with an SCE reference electrode (the ferrocene/ferrocenium
(Fc/FC+) redox couple as external standard), platinum-button
working electrodes, and a platinum-wire counter electrode, as
shown in Fig. 10. Onset oxidation potentials of 4a–c can be
calculated from Fig. 10 to be 0.92, 1.04, and 0.96 eV,
respectively. Thus, the HOMO values for 4a–c are 25.18,
25.32, and 25.22 eV, respectively, derived from onset
oxidation potentials given above. The band gaps of 4a–c can
be determined from their onset absorption wavelengths and
are calculated to be 2.57, 2.61, and 2.87 eV, respectively.
prior to use. DMF was refluxed with calcium hydride and
distilled before use. Starting materials bis(4-fluorophenyl)-
methanone and diphenylamine was from commercial sources
(J&K, Aldrich), and used without further purification. The key
intermediate compounds were prepared according to the
previous published procedures.
Bis(4-(diphenylamino)phenyl)methanone (1a): In a two-neck
flask, diphenylamine (6.2 g 36.7 mmol) and sodium tert-
butoxide (5.28 g 55 mmol) were dissolved in 100 mL
anhydrous DMF, slowly dropped into this was bis(4-fluoro-
phenyl)methanone (4 g 18.3 mmol) in a 50 mL anhydrous DMF
solution under N2 atmosphere over 1 h. The reaction mixture
was refluxed for 10 h, upon cooling the mixture was poured
into 200 mL ice water, then a deep yellow solid precipitate was
filtered off and washed with ethanol. After vacuum drying a
Conclusions
1
7.85 g yellow solid was obtained. Yield: 83%; H NMR (CDCl3,
In this work, we have designed and synthesized three
luminogenic molecules 4a–c. All the compounds are stable
and show high thermal stability, only losing 5% of their
weights when they are heated to 482–503 uC. They are almost
non-emissive when dissolved in pure THF, and become strong
when aggregated in aqueous media, demonstrating a phe-
nomenon of aggregation-induced emission. When the water
ratio reaches 70% the PL intensity was the highest, and exhibit
strongly enhanced orange, deep yellow and green fluorescence
emissions, respectively. The solid fluorescence of 4a–c is
located at 590, 579 and 547 nm, with the corresponding WF of
values being 9.2%, 2.4%, and 14.5%, respectively. And the
emissions of film display the maximum at 581, 569 and 543
nm. All molecules exhibit the feature of aggregation-enhanced
two-photon excited fluorescence. Their values of 2PA cross
section are 511 GM, 257 GM, and 180 GM, respectively, at
wavelength 800 nm. These good properties can make them as
potential materials for biophotonic applications.
400 MHz, TMS), d: 7.74 (m, 4H), 7.35 (m, 8H), 7.22 (m, 8H),
7.14 (m, 4H), 7.02 (d, J = 8.8 Hz, 4H). Bis(4-(9H-carbazol-9-
yl)phenyl)methanone (1b): Compound 1b was synthesized by
the same procedure as described above for 1a using bis(4-
fluorophenyl)methanone and carbazole. Yield: 75% 1H NMR
(CDCl3, 400 MHz, TMS) d: 8.18 (dd, J = 8.1, 3.1 Hz, 8H), 7.80 (d,
J = 8.5 Hz, 4H), 7.57 (d, J = 8.2 Hz, 4H), 7.48 (m, 4H), 7.37 (m,
4H). 2-(4-Bromophenyl)-3,3-bis(4-(diphenylamino)phenyl)acry-
lonitrile (2a): Compound 1a (3g 5.8 mmol), 60% NaH (0.92 g
23.2 mmol) were put into a two-neck flask and dissolved into
50 mL dry toluene, to this was slowly dropped 2-(4-bromophe-
nyl)acetonitrile (1.13 g, 5.8 mmol) in 50 mL dry toluene
solution over 40 min. The mixture was stirred and refluxed for
8 h under N2 atmosphere, upon cooling, poured the mixture
into water and extracted with CH2Cl2 (50 mL 6 3), the
combined organic layer was washed with water and was dried
over anhydrous MgSO4, concentrated using a rotary evapora-
tor. The residue was purified by column chromatography on
silica (petroleum ether/CH2Cl2 = 4 : 1 v/v) to give a yellow solid
(2.45 g). Yield:73%; 1H NMR (DMSO-d6, 400 MHz, TMS) d: 7.53
(d, J = 8.5 Hz, 2H), 7.36 (dt, J = 15.2, 7.8 Hz, 10H), 7.21 (m,
10H), 7.03 (d, J = 7.8 Hz, 4H), 6.92 (d, J = 8.8 Hz, 2H), 6.87 (d, J =
8.5 Hz, 2H), 6.75 (d, J = 8.6 Hz,2H). 3,3-Bis(4-(9H-carbazol-9-
yl)phenyl)-2-(4-bromophenyl)acrylonitrile (2b): Compound 2b
was synthesized by the same procedure as described above for
Experimental section
Instruments
1H and 13C NMR spectra were measured on a Bruker AM-400
spectrometer using d-chloroform as solvent and tetramethyl-
silane (TMS, d = 0 ppm) as internal standard. Mass spectra
were recorded on an ESI mass spectrometer. The UV/Vis
spectra were recorded on a Nicolet CARY 100 spectrophot-
1
2a using compound 1b and 2-(4-bromophenyl)acetonitrile. H
NMR (CDCl3, 400 MHz, TMS) d: 8.16 (t, J = 7.1 Hz, 4H), 7.83 (d,
J = 8.4 Hz, 2H), 7.74 (d, J = 8.5 Hz, 2H), 7.56 (dd, J = 13.2, 8.3
Hz, 4H), 7.46 (m, 8H), 7.32 (m, 8H). 3,3-Bis(4-(diphenylami-
no)phenyl)-2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-
yl)phenyl)acrylonitrile (3a): Compound 2a (2g 2.88 mmol),
bis(pinacolato)diboron (1.1g 4.32 mmol), KOAc (0.85 g 8.64
mmol) and Pd(dppf)Cl2 (10 mg) were dissolved into 50 mL
anhydrous dioxane, under N2 atmosphere the mixture were
heated to 80 uC, then stirred for 10 h, upon cooling, the
mixture was poured into water and extracted with CH2Cl2 (20
mL 6 3), the combined organic layer was washed with water
and was dried over anhydrous MgSO4 and then concentrated
using a rotary evaporator. The residue was purified by column
chromatography on silica (petroleum ether/CH2Cl2=3 : 1 v/v)
ometer. The PL spectra were taken on
a Varian-Cary
fluorescence spectrophotometer. The quantum yield for solid
powders was measured by Quanta-w F-3029 Integrating Sphere.
The 2PA cross sections were measured by a femtosecond open-
aperture Z-scan technique according to a previously described
method. The TPF was achieved using femtosecond pulses with
different intensities at a wavelength of 800 nm. The repetition
rate of the laser pulses was 250 KHz and the pulse duration
was 80 fs. The cyclic voltammograms of 4a–c were obtained
using a Versastat II electrochemical workstation.
Materials
1
to give a yellow solid (1.4 g). Yield: 65% H NMR (CDCl3, 400
THF was pre-dried over sodium for 24 h and then redistilled
under argon atmosphere with sodium benzophenone ketyl
MHz, TMS) d: 7.66 (d, J = 8.2 Hz, 2H), 7.29 (m, 12H), 7.17 (d, J =
7.5 Hz, 4H), 7.06 (dt, J = 17.0, 8.3 Hz, 10H), 6.81 (dd, J = 20.8,
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8.8 Hz, 4H), 1.35 (s, 12H). 3,3-Bis(4-(9H-carbazol-9-yl)phenyl)-2-
(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)acryloni-
trile (3b): Compound 3b was synthesized by the same
procedure as described above for 3a using compound 2b and
bis(pinacolato)diboron. 1H NMR (CDCl3, 400 MHz, TMS) d:
8.15 (dd, J = 11.2, 5.8 Hz, 4H), 7.83 (t, J = 5.7 Hz, 2H), 7.75 (m,
4H), 7.57 (t, J = 7.3 Hz, 2H), 7.45 (m, 10H), 7.32 (m, 6H), 1.36 (s,
Acknowledgements
This work was supported by NSFC/China (20772031), the
National Basic Research 973 Program (2006CB806200), the
Fundamental Research Funds for the Central Universities
(WJ0913001), and the Scientific Committee of Shanghai
(10520709700).
12H).
2,2’-(Biphenyl-4,4’-diyl)bis(3,3-bis(4-(diphenylamino)-
phenyl)acrylon-itrilee) (4a): Compound 3a (0.3g 0.4mmol),
compound 2a (0.28 g 4 mmol) were dissolved in 20 mL THF,
then was put 7 mL saturated sodium bicarbonate solution and
5 mg Pd(dppf)Cl2, under N2 atmosphere the mixture were
heated to 80 uC, then stirred for 8 h. Upon cooling, the mixture
was poured into water and extracted with CH2Cl2 (10 mL 6 3),
the combined organic layer were washed with water and was
dried over anhydrous MgSO4, then concentrated using a rotary
evaporator. The residue was purified by column chromato-
graphy on silica (petroleum ether/CH2Cl2 = 2 : 1 v/v) to give an
orange solid (0.31 g). Yield: 63%.1H NMR (CDCl3, 400 MHz,
TMS) d: 7.46 (d, J = 8.5 Hz, 4H), 7.37 (dd, J = 8.7, 2.2 Hz, 8H),
7.31 (m, 10H), 7.23 (d, J = 7.6 Hz, 6H), 7.18 (d, J = 7.5 Hz, 8H),
7.07 (m, 20H), 6.86 (dd, J = 32.4, 8.8 Hz, 8H); 13C NMR (CDCl3,
100 MHz, TMS), d: 157.60, 155.70, 149.54, 148.66, 146.94,
146.83, 140.25, 133.90, 132.36, 131.49, 129.49, 126.81, 126.16,
125.30, 123.72, 120.49, 119.91, 112.11, 109.93, 109.65, 107.04;
HRMS (m/z): [M]+ calcd for: C90H64N6, 1229.5271, found:
1229.5278. Anal. calcd for C90H64N6: C, 87.92; H, 5.25; N, 6.84.
Found: C, 87.81; H, 5.33; N, 6.54. 3,3-Bis(4-(9H-carbazol-9-
yl)phenyl)-2-(4’-(1-cyano-2,2-bis(4-(diphen-ylamino)phenyl)vi-
nyl)biphenyl-4-yl)acrylonitrile (4b): Compound 4b was synthe-
sized by the same procedure as described above for 4a using
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1
compound 2b and compound 3a. Yield: 65%. H NMR (CDCl3
400 MHz, TMS) d: 8.15 (dd, J = 12.6, 7.8 Hz, 4H), 7.81 (dd, J =
42.7, 8.3 Hz, 4H), 7.57 (m, 6H), 7.38 (m, 24H), 7.20 (dd, J = 18.1,
8.0 Hz, 8H), 7.06 (m, 10H), 6.86 (dd, J = 35.2, 8.6 Hz, 4H). 13C
NMR (CDCl3, 100 MHz), d: 154.72, 149.50, 148.65, 146.98,
146.89, 139.40, 135.30, 132.81, 132.36, 131.80, 131.49, 130.17,
129.50, 129.41, 126.73, 125.60, 125.30, 124.00, 123.89, 121.19,
120.90, 120.66, 107.23; HRMS (m/z): [M]+ calcd for: C90H60N6,
1225.4958, found: 1225.4957. Anal. calcd for: C90H60N6, C,
88.21; H, 4.93; N, 6.86. Found: C, 88.13; H, 5.09; N, 6.71. 2,2’-
(Biphenyl-4,4’-diyl)bis(3,3-bis(4-(9H-carbazol-9-yl)phenyl)a-
crylo-nitrile) (4c): Compound 4c was synthesized by the same
procedure as described above for 4a using compound 3a and
compound 3b. Yield: 63%. 1H NMR (CDCl3, 400 MHz, TMS) d:
8.16 (t, J = 7.2 Hz, 8H), 7.77 (dd, J = 34.6, 8.5 Hz, 8H), 7.57 (d, J
= 8.2 Hz, 4H), 7.52 (d, J = 8.4 Hz, 4H), 7.45 (dd, J = 11.5, 5.4 Hz,
12H), 7.33 (m, 16H), 6.80 (d, J = 8.6 Hz, 4H); 13C NMR (CDCl3,
100 MHz), 163.16, 158.69, 145.07, 145.01, 143.11, 142.38,
137.32, 136.70, 136.26, 131.83, 131.62, 131.53, 129.95, 128.22,
125.83, 125.53, 120.78, 117.48, 114.81; HRMS (m/z): [M]+ calcd
for: C90H56N6, 1221.4645, found: 1221.4647. Anal. Calcd for:
C90H56N6, C, 88.50; H, 4.62; N, 6.88. Found: C, 88.61; H, 4.69;
N, 6.74.
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