JOURNAL OF POLYMER SCIENCE: PART A: POLYMER CHEMISTRY DOI 10.1002/POLA
multifunctional polymers in which hole transporting, elec-
tron transporting, and emitting abilities are included by
means of random or block copolymerizations.11–13
added dropwise, the mixture was stirred at 0 ꢀC for 3 h.
Additional stirring was continued at room temperature for 5
h. The resulting mixture was poured into water, and the pre-
cipitation was filtered. The crude product was dispersed in
small amount of THF, filtered, and washed with water. The
white solid was obtained after drying under vacuum. The
Block copolymers assemble into micro- or nano-phase sepa-
rated structures with various domain shapes such as lamella,
cylinder, or sphere. Exploiting nanostructures of block
copolymers with appropriate designs can improve perform-
ance of applications due to allocation of functionality to each
domain.14,15 Fluorine containing segments in block copoly-
mers were well known as surface modifiers that gather to-
ward the interface between air and polymers, and change
the surface to hydrophobic16,17 or antifouling.18,19 In this ar-
ticle, we prepared a series of block copolymers consisting of
triarylamine and oxadiazole monomers as hole and electron
transporting units, respectively. Trifluoromethyl groups were
introduced into an oxadiazole monomer to create a pseudo-
layered structure by dragging electron transporting segments
into the surface during film formation. The light-emitting
properties of the block copolymers were examined and were
compared with those of random copolymers and polymer
blends with the similar monomer compositions.
ꢀ
yield was 25.2 g (61.1%). Mp: 110.7 C (DSC).
1H NMR (500 MHz, DMSO-d6, d, ppm): 11.12 (s, 1H), 10.91
(s, 1H), 8.57 (s, 2H), 8.41 (s, 1H), 8.10 (d, 2H), 8.04 (d, 2H),
3.89 (s, 3H). 13C NMR (125 MHz, DMSO-d6, d, ppm): 165.65,
165.12, 162.97, 136.37, 134.49, 132.60, 130.85 (q, J ¼ 34
Hz), 129.44, 128.31, 128.01, 125.85, 123.06 (q, J ¼ 272 Hz),
52.51. HRMS (m/z): calcd for C18H12F6N2O4, 435.0780;
found, 435.0604 [M þ H]þ.
Synthesis of 2-[3,5-Bis(trifluoromethyl)phenyl]-5-(4-
methoxycarbonylphenyl)-1,3,4-oxadiazole (5)
To a two-necked flask equipped with a stopcock and a con-
denser were added 4 (6.51 g, 15.0 mmol) and phosphoryl
chloride (60 mL) under nitrogen atmosphere, and the mix-
ꢀ
ture was stirred at 100 C for 12 h. Phosphoryl chloride was
removed by vacuum distillation, and water was added to
wash the resulting mixture. After vacuum filtration and dry-
ing, the crude compound was recrystallized from toluene to
give aꢀ white crystal. The yield was 4.53 g (72.6%). Mp:
113.3 C (DSC).
EXPERIMENTAL
Materials
Toluene was distilled over calcium hydride and stored under
nitrogen. Tetrahydrofuran (THF), diethyl ether, and diglyme
(diethyleneglycol dimethyl ether) were used after the distil-
lation over sodium and benzophenone. 3-Vinyltriphenylamine
(1),20 4-vinylbenzyl 4-[5-(4-t-butylphenyl)-1,3,4-oxadiazole-
2-yl]benzoate (2),21 and N-(1-phenylethoxy)-N-(2-methyl-1-
phenylpropyl)-t-butylamine (8)22 were synthesized as
reported in literatures. The other reagents were used as
received.
1H NMR (500 MHz, CDCl3, d, ppm): 8.60 (s, 2H), 8.26 (d,
2H), 8.22 (d, 2H), 8.08 (s, 1H), 3.98 (s, 3H). 13C NMR (125
MHz, CDCl3, d, ppm): 166.12, 164.95, 162.83, 133.60, 133.19
(q, J ¼ 35 Hz), 130.56, 127.29, 127.10, 127.01, 125.90,
125.44, 122.83 (q, J ¼ 273 Hz), 52.72. HRMS (m/z): calcd
for C18H10F6N2O3, 417.0674; found, 417.0698 [M þ H]þ.
Synthesis of 4-[5-(3,5-Bis(trifluoromethyl)phenyl)-1,3,4-
oxadiazole-2-yl]benzoic Acid (6)
Synthesis of 3,5-Bis(trifluoromethyl)
benzoylhydrazine (3)
To the solution of sodium hydroxide (0.870 g, 15.5 mmol) in
small amount of water was added the dispersion of 5 (3.23
g, 7.75 mmol) in THF (30 mL) and ethanol (90 mL), and the
To a three-necked flask equipped with a stopcock and a con-
denser were added methyl 3,5-bis(trifluoromethyl)benzoate
(18.5 g, 9.60 mmol) and methanol (12 mL) under nitrogen
atmosphere and stirred for 30 min. After hydrazine monohy-
drate (3.00 mL, 62.0 mmol) and methanol (12 mL) were
added to the solution, the mixture was stirred at 40 ꢀC for
16 h. The solution was concentrated and washed with water.
After drying a white solid was obtained. The yield was
ꢀ
mixture was stirred at 70 C for 3 h. After water was added
to the mixture at room temperature, insoluble solid was
removed by vacuum filtration. To the filtrate was added 0.5
N HCl aq. until pH of the solution became 2. The precipita-
tion was filtered and washed with water three times. After
drying, slightly pinkish soꢀlid was obtained. The yield was
2.20 g (67.7%). Mp: 136.7 C (DSC).
ꢀ
15.1 g (81.6%). Mp: 135.9 C (DSC).
1H NMR (500 MHz, DMSO-d6, d, ppm): 10.27 (s, 1H), 8.45 (s,
2H), 8.23 (s, 1H), 4.66 (s, 2H). 13C NMR (125 MHz, DMSO-d6,
d, ppm): 162.59, 135.53, 130.90 (q, J ¼ 33 Hz), 127.77,
124.67, 123.13 (q, J ¼ 272 Hz). HRMS (m/z): calcd for
C9H6F6N2O, 273.0463; found, 273.0528 [M þ H]þ.
1H NMR (500 MHz, DMSO-d6, d, ppm): 11.10 (s, 1H), 8.70 (s,
2H), 8.40 (s, 1H), 8.32 (d, 2H), 8.13 (d, 2H). 13C NMR (125
MHz, CDCl3, d, ppm): 167.62, 165.19, 163.34, 136.90, 134.83,
132.07 (q, J ¼ 33 Hz), 131.06, 128.31, 128.23, 127.41,
126.39, 123.76 (q,
J
¼
272). HRMS (m/z): calcd for
C
17H8F6N2O3, 403.0517; found, 403.0530 [M þ H]þ.
Synthesis of 1-[3,5-Bis(trifluoromethyl)benzoyl]-2-(4-
methoxycarbonylbenzoyl)hydrazine (4)
To a two-necked flask equipped with a stopcock and an addi-
tion funnel were added 3 (41.2 g, 150 mmol) and pyridine
(250 mL) and cooled down to 0 ꢀC under nitrogen atmos-
phere. After the solution of terephthalic acid monomethyl
ester chloride (29.9 g, 151 mmol) in pyridine (250 mL) was
Synthesis of 4-Vinylbenzyl 4-[5-(3,5-Bis(trifluoromethyl)
phenyl)-1,3,4-oxadiazole-2-yl]benzoate (7)
To a two-necked flask equipped with a stopcock and a con-
denser were added 6 (2.19 g, 5.24 mmol), sodium bicarbon-
ate (0.661 g, 7.87 mmol), and dimethylformamide (30 mL)
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