A. Liang et al.
Dyes and Pigments 180 (2020) 108526
other hand, triphenylamine (TPA) and its derivatives are mostly used in
OLEDs as hole-transporting materials for their excellent luminescence
properties, good electron-donating ability and hole transporting capa-
bility. Recently, TPA moiety was widely used in the construction of new
AIE luminogens owing to its three phenyl rotors and the non-planar
structure [28–30]. The rotational motion of the phenyl rings is benefi-
cial for dissipating excited-state energy in solution and restricting the
intramolecular rotation (RIR) in the solid-state.
6H).
After degassing, Pd(PPh3)4 (35 mg) was added to a mixture of 3 (938
mg, 1.5 mmol), N-phenyl-N-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-
2-yl)phenyl) benzenamine (668 mg, 1.8 mmol), THF (50.0 mL) and aq.
2.0 M K2CO3 solution (20.0 mL). The reaction mixture was heated to
reflux with vigorously stirring for 18 h under an N2 flow protection.
After cooling to RT, the mixture was poured into water and extracted
with DCM (3 � 30 mL). The combined organic layers were collected,
dried over anhydrous MgSO4 and evaporated to remove the solvent. The
resulted crude product was purified by column chromatography on sil-
ica gel (hexane/DCM ¼ 13/1) to give TPA–FSO–TPE (948 mg) in a yield
of 80%. 1H NMR (400 MHz, CDCl3) δ (ppm): 7.99 (d, J ¼ 6.2 Hz, 2H),
7.80 (d, J ¼ 5.7 Hz, 4H), 7.49 (d, J ¼ 8.6 Hz, 2H), 7.38 (d, J ¼ 8.3 Hz,
2H), 7.30 (t, J ¼ 7.9 Hz, 4H), 7.18–7.01 (m, 25H). 13C NMR (CDCl3, 100
MHz) δ (ppm): 147.29, 145.02, 144.15, 143.37, 141.75, 140.07, 138.73,
136.37, 132.04, 131.54, 131.26, 131.18, 130.02, 129.39, 127.80,
127.69, 127.44, 126.62, 126.55, 125.99, 124.78, 123.45, 123.02,
121.86, 121.71, 120.23, 119.74. Anal. Calcd. for C56H39NO2S: C, 85.14;
H, 4.98; N, 1.77; S, 4.06; Found: C, 85.12; H, 4.93; N, 1.79; S, 4.09.
HRMS (ESI): calcd for C56H39NO2S: 789.2072, found 789.2079.
In this manuscript, we have synthesized three well-defined D-A
structure SO derivatives by Pd(0)-catalyzed Suzuki cross coupling re-
action. The photophysical, thermal, electrochemical and electrolumi-
nescent (EL) properties, as well as the AIE property of the resulting
luminogens are discussed. All the luminogens show high thermal sta-
bility with a Td above 300 �C and exhibit an absolute photoluminescence
quantum yield above 60%. The device of TPA–FSO–TPA showed the best
performances with a Von of 4.0 V, LEmax of 10.05 cd AÀ 1 and Lmax of
14,670 cd mÀ 2. The EL spectra of the devices based on TPA–FSO–TPA,
TPA–FSO–TPE and TPE–FSO–TPE show negligible shift by changing the
operating voltage, which indicate that good device stability could be
achieved in this system.
2.1.3. Synthesis of TPE–FSO–TPE
2. Experimentals
To a mixture of 3,7-dibromodibenzothiophene-S,S-dioxide (374 mg,
1.0 mmol), 4,4,5,5-tetramethyl-2-(4-(1,2,2-triphenylvinyl)phenyl)-
1,3,2-dioxaborolane (1.15 g, 2.5 mmol), THF (60.0 mL) and aq. 2.0 M
K2CO3 solution (20.0 mL), Pd(PPh3)4 (58 mg) was added after degass-
ing. The mixture was heated to reflux with vigorously stirring for 24 h
under an N2 flow protection. After cooling to RT, the mixture was
poured into water and extracted with DCM. The organic layer was dried
over anhydrous MgSO4 and evaporated to remove the solvent. The
resulted crude product was purified by column chromatography on sil-
ica gel (hexane/DCM ¼ 25/1) to give TPE–FSO–TPE (684 mg) in a yield
of 78%. 1H NMR (400 MHz, CDCl3) δ (ppm): 7.98 (s, 2H), 7.80 (s, 4H),
2.1. Materials
3,7-Dibromodibenzothiophene-S,S-dioxide (1) [31], 4,4,5,5-tetra-
methyl-2-(4-(1,2,2-triphenylvinyl)phenyl)-1,3,2-dioxaborolane
(2)
[32] and N-phenyl-N-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)
phenyl) benzenamine (4) [33] were prepared according to the reported
procedures. All reactions were performed under nitrogen. All solvents
were carefully dried and distilled from appropriate drying agents prior
to use. Commercially available reagents were used without further pu-
rification unless otherwise stated.
7.38 (d, J ¼ 8.3 Hz, 4H), 7.17–7.09 (m, 22H), 7.09–7.01 (m, 12H). 13
C
NMR (CDCl3, 100 MHz) δ (ppm): 144.2, 143.4, 143.3, 143.1, 141.7,
140.0, 138.5, 13 6.4, 132.1, 131.3, 129.9, 127.8, 127.6, 126.7, 126.6,
126.5, 126.1, 121.7, 120.4. Anal. Calcd. for C64H44O2S: C, 87.64; H,
5.06; S, 3.66; Found: C, 87.68; H, 5.08; S, 3.69. HRMS (ESI): calcd for
C64H44O2S: 876.3062, found 876.3069.
2.1.1. Synthesis of TPA–FSO–TPA
After degassing, Pd(PPh3)4 (58 mg) was added to the mixture of 3,7-
dibromodibenzothiophene-S,S-dioxide (374 mg, 1.0 mmol), N-phenyl-
N-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)
benzen-
amine (928 mg, 2.5 mmol), THF (60.0 mL) and aq. 2.0 M K2CO3 solution
(20.0 mL). The mixture was heated to reflux with vigorously stirring for
18 h under an N2 flow protection. After cooling to room temperature
(RT), the mixture was poured into water and extracted with dichloro-
methane (DCM). The organic layer was dried over anhydrous MgSO4
and evaporated to remove the solvent. The resulted crude product was
purified by column chromatography on a silica gel (hexane/DCM ¼ 20/
1) to give TPA–FSO–TPA (569 mg) in a yield of 81%. 1H NMR (400 MHz,
CDCl3) δ (ppm): 8.00 (s, 2H), 7.80 (s, 4H), 7.50 (d, J ¼ 8.7 Hz, 4H),
7.34–7.27 (m, 8H), 7.15 (d, J ¼ 7.4 Hz, 12H), 7.08 (t, J ¼ 7.3 Hz, 4H).
13C NMR (CDCl3, 100 MHz) δ (ppm): 147.82, 147.66, 134.32, 132.62,
129.54, 128.01, 125.96, 124.15, 122.68. Anal. Calcd. for C48H34N2O2S:
C, 82.02; H, 4.88; N, 3.99; S, 4.56; Found: C, 82.08; H, 4.86; N, 3.92; S,
4.52. HRMS (ESI): calcd for C47H36N2O2S: 702.8608, found 702.8612.
2.2. Measurements and characterization
1H and 13C NMR spectra were recorded on a Bruker 400 spectrometer
operating respectively at 400 and 100 MHz at room temperature.
Chemical shifts were reported as δ values (ppm) relative to an internal
tetramethylsilane (TMS) standard. High resolution mass spectrometry
was acquired in positive Electrospray mode (ESI) on an LTQ Orbitrap XL
instrument (Thermo Fisher Scientific). Elemental analyses were carried
out with an Eurovector EA 3000 CHN instrument. Thermogravimetric
analysis (TGA) was carried out on a Diamond TG/DTA instrument under
a nitrogen atmosphere at a heating rate of 20 �C minÀ 1 and Td was re-
ported as the temperatures at 5% weight losses. UV–vis absorption
spectra were measured on a HP 8453 spectrophotometer. PL spectra
were recorded on an Instaspec IV CCD spectrophotometer (Oriel Co.)
under 325 nm excitation of a HeCd laser. Cyclic voltammetry was car-
ried out on a CHI660A electrochemical workstation in a solution of
tetrabutylammonium hexafluorophosphate (Bu4NPF6) (0.1 M) in
acetonitrile at a scan rate of 50 mV/s at room temperature under the
protection of argon. A platinum electrode was used as the working
electrode. A Pt wire was used as the counter electrode, and a calomel
electrode was used as the reference electrode. The absolute photo-
luminescence quantum yield (ФPL) was measured with a Hamamatsu
absolute PL quantum yield spectrometer equipped with an integrating
sphere (Quantaurus-QY, C11347).
2.1.2. Synthesis of TPA–FSO–TPE
4,4,5,5-tetramethyl-2-(4-(1,2,2-triphenylvinyl)phenyl)-1,3,2-dioxa-
borolane (1.38 g, 3.0 mmol), 3,7-dibromodibenzothiophene-S,S-dioxide
(1.12 g, 3.0 mmol), Pd(PPh3)4 (69 mg), THF (70.0 mL) and aq. 2.0 M
K2CO3 solution (20.0 mL) were added in a 150 mL flask. The mixture
was heated to reflux for 16 h under argon atmosphere. After cooling to
RT, the mixture was poured into brine and extracted twice with DCM.
The combined organic layers were dried over MgSO4 and the solvent
was removed. The crude product was purified with column chroma-
tography on silica gel (hexane/DCM ¼ 20/1) to yield 1.01 g (58%) of 3
as yellow solid. 1H NMR (400 MHz, CDCl3) δ (ppm): 1H NMR (400 MHz,
CDCl3) δ 7.95 (d, J ¼ 11.0 Hz, 2H), 7.83–7.72 (m, 3H), 7.65 (d, J ¼ 8.2
Hz, 1H), 7.37 (d, J ¼ 8.3 Hz, 2H), 7.19–7.09 (m, 11H), 7.09–7.00 (m,
2