M. Qin, Z. Wu, J. Zhang et al.
Journal of Molecular Liquids 339 (2021) 116626
have important guiding significance for the molecular design and
application expansion of AIEgenes.
HRMS (ESI): m/z [M+H] + calcd for C55
720.3696.Scheme 1.
H46N 720.3552; found
2
. Experimental Section
3. Results and Discussion
2
.1. Synthesis of TPE-CH
3
We investigated the UV-vis absorption of Di-TPE (Figure 1a).
Both Di-TPE and TPE have two absorption peaks, which are due
to the conjugated structure of the molecules. Both molecules have
Bromotristyrene (4.0 g, 11.95 mmol, 1.00 eq), p-
methylphenylboric acid (2.43 g, 17.93 mmol, 1.50 eq) and tetram-
ethylammonium bromide (384.5 mg, 1.2 mmol, 0.10 eq) were
placed in a 250ml round bottom flask under the protection of
p – p* transition and local excitation. The absorption peaks of TPE
molecule appear at 240 nm and 305 nm, and the absorption peaks
of Di-TPE appear at 258 nm and 313 nm. Compared with TPE, Di-
TPE has a red shift of 18 nm. This is due to the fact that there are
two conjugated structures in the Di-TPE molecule. The two tetra-
phenylvinyl groups in the molecule have intramolecular interac-
tions. In addition, the conjugated structure of the lone pair
electron on the N atom and the conjugated structure of the tetra-
phenylethylene group in the Di-TPE molecule have the hypercon-
jugation effect, which leads to the absorption of Di-TPE red shift.
In order to study the aggregation-induced emission properties
of Di-TPE molecules, we measured the emission of Di-TPE in differ-
2 3
argon gas, and toluene (50ml) and 2 mol/L K CO (20ml) were
added. Stirring at 90℃for 10 minutes, four (triphenylphosphine)
palladium (477.0 mg, 0.4 mmol, 0.03 eq) was added, and the reac-
tion continued for 11 hours. After the reaction, ethyl acetate was
used for extraction three times, and Na
water. The crude product was separated by silica gel column chro-
matography. After the experiment, the white solid TPE-CH 2.64 g
: H NMR (400 MHz,
Chloroform-d) d 7.19 – 6.96 (m, 15H), 6.90 (d, J = 2.1 Hz, 4H), 2.25
d, J = 2.1 Hz, 3H).
2 4
SO was dried without
3
1
was obtained and the yield was 66%. TPE-CH
3
(
2
ent proportions of THF/H O. As shown in Figure 1c, with the
increase of water content in the mixed solution system, the fluo-
rescence emission intensity of Di-TPE gradually increases, espe-
cially when the water content increases to 90%, the fluorescence
emission intensity will increase sharply. Di-TPE has large solubility
in tetrahydrofuran, but very small solubility in water, so THF is a
good solvent for Di-TPE, and water is a poor solvent. In the mixed
solution of THF/H O with different proportions, the gradual
2
increase of water ratio will cause Di-TPE to aggregate in the solu-
tion, the molecular packing will become more and more tight,
2
.2. Synthesis of TPE-CH
2
-Br
Under the protection of argon, compound TPE-CH
.612 mmol, 1.00 eq), N-bromosuccinimide (1.436 g, 8.069 mmol,
.06 eq) and benzoyl peroxide (18.43 mg, 0.0761 mmol, 0.01 eq)
3
(2.64 g,
7
1
were placed in a 50 ml round bottom flask, and carbon tetrachlo-
ride (35 ml) was added. After refluxing at 100 ℃ for 8 hours, the
reactants were cooled to room temperature and added with a
few drops of water for stirring. The crude solvent was removed
by vacuum distillation and separated by silica gel column chro-
matography (petroleum ether) to obtain white solid B. After the
experiment, 1.08 g white solid was obtained and the yield was
4
7
the
p-p interaction between molecules will become more and
more intense, so that the emission intensity will increase rapidly.
When TPE does not aggregate, the difference between the emission
wavelength and intensity and Di-TPE is very small, the emission
wavelength of Di-TPE is slightly red-shifted, and the emission
intensity increases slightly (Figure 1d). In the aggregation state,
the emission wavelengths of Di-TPE and TPE are quite different.
The emission wavelength of TPE is red-shifted to 457 nm,
and the emission wavelength of Di-TPE is red-shifted to 478 nm.
The emission intensity of Di-TPE is slightly smaller than that of
TPE. It is related to the molecular stacking mode and the molecular
conformation after stacking, which we will discuss in detail below.
In the meantime, we analysed the variation of the emission inten-
1
1%. TPE-CH
2
-Br: H-NMR (400 MHz, Chloroform-d) d 7.19 –
.05 (m, 15H), 7.01 (d, J = 9.7 Hz, 4H), 4.42 (d, J = 12.0 Hz, 2H).
2
.3. Synthesis of the Di-TPE
TPE-CH
2
-Br (150 mg, 0.354 mmol), methylamine ethanol solu-
CO (333.35 mg, 2.412 mmol) were
tion (56 L, 0.550 mmol), K
refluxed overnight in acetonitrile (50ml), and the refluxing temper-
l
2
3
ature was set to 84 ℃. At the end of the experiment, silica gel col-
2
sity of Di-TPE molecules with the concentration in the THF/H O
umn chromatography was used to separate the white solid 0.0502
mixed solution system with 95% water content (Figure 1e). With
the increase of molecular concentration, the fluorescence emission
intensity also gradually increases. Because when the content of
1
g, and the yield was 33.5%. Di-TPE:
H NMR (400 MHz,
Chloroform-d) d 7.16 – 6.92 (m, 38H), 3.35 (s, 4H), 2.10 (s, 3H).
Scheme 1. Synthesis route of Methyl-bis-(4-triphenylvinyl-benzyl)-amine (Di-TPE)
2