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C.-H. Chang et al. / Polymer 51 (2010) 4493e4502
aminohenyl)-N0,N0-bis[4-(2-phenyl-2-isopropyl)-phenyl]-1,4-phe-
nylene-diamine. In addition, organosoluble copolyimides were
also prepared from rigid fluorine-containing dianhydrides. To
gain more insight into the oxidation mechanism, the compu-
tational study on the electronic structures of the basic unit, M3,
was also studied based on DFT(B3LYP/6-31G(d)) calculations.
IR (KBr) 1585, 1342 cmꢁ1(NO2 stretch) 1H NMR. (CDCl3):
d
(ppm) ¼ 1.77 (s, 12H, Hd), 6.93e6.95 (d,4H, Hf, J ¼ 9.4 Hz),
7.12e7.14 (d, 4H, He, J ¼ 10.05 Hz), 7.24e7.27 (m, 2H, Ha), 7.28e7.30
(d, 2H, Hh, J ¼ 10.05 Hz), 7.35e7.36 (m, 4H, Hb), 7.37e7.38 (d, 4H, Hc,
J ¼ 5.02 Hz), 8.05e8.08 (d, 2H, Hg, J ¼ 9.3 Hz). 13C NMR (CDCl3):
d
(ppm) ¼ 30.6 (C6), 42.6 (C5), 117.4 (C12), 125.3 (C13), 125.7 (C1), 125.9
(C9), 126.6 (C2), 128.0 (C3), 128.1 (C8), 139.6 (C14), 142.8 (C10), 148.2
(C7), 150.0 (C4), 153.4 (C11). ELEM. ANAL. Calcd. for C36H34N2O2: C,
82.10%; H, 6.51%; N, 5.32%. Found: C, 81.67%; H, 6.39%; N, 5.21%.
NO2
14
h
13
6
d
g
12
3
2
e
c
f
9
8
b
CH3
CH3
5C
11
10
7
4
1
a
C
N
CH3
CH3
2.2.2. Synthesis of bis[4-(2-phenyl-2-isopropyl)phenyl]-4-
aminophenylamine (2)
In a 500 mL three neck round-bottom flask the nitro compound
1 (20 g, 38 mmol), Pd/C (0.4 g), and ethanol (200 mL) were added.
After the addition of 14 mL of hydrazine monohydrate, the solution
was stirred at reflux temperature for 12 h. After the solution was
cooled down to room temperature, the solution was filtered to
remove the catalyst, and the crude product was recrystallized from
ethanol yielding 12.5 g (yield: 66%) of the compound 2, mp
110e114 ꢀC by DSC (10 ꢀC/min).
2. Experimental
2.1. Materials
Bis[4-(2-phenyl-2-isopropyl)phenyl]amine (OUCHI SHINKO),
4-fluoro-nitrobenzene (ACROS), cesium fluoride (ACROS), sodium
hydride (95%; dry; ALDRICH), 10% Pd/C (MERCK), and hydrazine
monohydrate (MERCK) were used as received. N,N-Dimethylace-
tamide (DMAc; MERCK), dimethyl sulfoxide (DMSO; MERCK),
N-methyl-2-pyrrolidinone (NMP; MERCK), and pyridine (MERCK),
were dried over calcium hydride overnight, distilled under
IR (KBr) 3432, 3356 cmꢁ1 (NH2 stretch). 1H NMR (DMSO-d6):
d
(ppm) ¼ 1.57 (s, 12H, Hd), 5.02 (s, 2H, NH2), 6.56e6.58 (d, 2H, Hg,
J ¼ 10 Hz), 6.77 (s, 4H, Hf), 6.79 (s, 4H, He), 6.98e7.00 (d, 2H, Hh,
J ¼ 10 Hz), 7.09e7.12 (m, 2H, Ha), 7.19e7.20 (d, 4H, Hb, J ¼ 5 Hz),
7.20e7.21(d, 4H, Hc, J ¼ 5 Hz). 13C NMR (DMSO-d6):
(ppm) ¼ 30.3
d
ꢀ
(C6), 41.7 (C5), 114.9 (C13), 120.73 (C9), 125.3 (C1), 126.2 (C3),
126.9 (C8), 127.8 (C2), 127.9 (C12), 135.2 (C14), 142.5 (C10), 145.4 (C7),
145.9 (C11), 150.3 (C4). ELEM. ANAL. Calcd. for C36H36N2: C, 87.05%;
H, 7.31%; N, 5.64%. Found: C, 86.9%; H, 7.13%; N, 5.61%.
reduced pressure, and stored over 4 A molecular sieves in a sealed
bottle. Iodobenzene, bis(dibenzylideneacetone) palladium [Pd
(dba)2], 1,10-bis(diphenylphosphino)-ferrocene (DPPF), sodium
tert-butoxide were purchased from ACROS. Commercially avail-
able aromatic tetracarboxylic dianhydrides such as 4,40-hexa-
fluoroisopropylidenediphathalic dianhydride (5a; CHRISKEV)
(6FDA), 4,40-oxydiphthalic anhydride (5b; TCI) (ODPA), 3,30,4,40-
diphenyl sulfone-tetracarboxylic dianhydride (5c; TCI) (DSDA),
3,30,4,40-benzophenone tetracarboxylic dianhydride (5d; CHRIS-
KEV) (BTDA), 3,30,4,40-biphenyltetracarboxylic dianhydride (5e;
CHRISKEV) (BPDA), and pyromellitic dianhydride (5f; CHRISKEV)
(PMDA were purified by vacuum sublimation. Tetra-n-buty-
lammonium perchlorate (TBAP) was obtained from ACROS and
recrystallized twice from ethyl acetate and then dried under
vacuum before use. All other reagents were used as received from
commercial sources.
NH2
14
h
13
d
g
6
12
3
2
e
c
f
9
8
b
CH3
CH3
5C
11
10
7
4
1
a
C
N
CH3
CH3
2.2.3. Synthesis of N,N,-bis(4-nitrophenyl)-N0,N0-bis[4-(2-phenyl-2-
isopropyl)phenyl]-1,4-phenylene-diamine (3)
In a 250 mL three neck round-bottom flask, bis-[4-(2-phenyl-2-
isopropyl)phenyl]-4-aminophenylamine (2) (7.26 g, 14.63 mmol),
4-fluoro-nitrobenzene (4.13 g, 29.27 mmol), cesium fluoride
(4.41 g, 29.27 mmol), and 80 mL DMSO were added. The mixture
was heated and stirred at 120 ꢀC for 24 h. The reaction mixture was
cooled and then poured into 500 mL of methanol. The red precip-
itate was collected by filtration and dried under vacuum. The
product was purified by silica gel column chromatography
(n-hexane:dichloromethane ¼ 1:1) resulting in dinitro compound
(3) in a 65% yield; mp 224e225 ꢀC (by DSC; 10 ꢀC/min).
2.2. Monomer synthesis
2.2.1. Synthesis of bis[4-(2-phenyl-2-isopropyl)phenyl]-4-
nitrophenylamine (1)
A 500 mL three neck round-bottom flask was filled with bis[4-(2-
phenyl-2-isopropyl)phenyl]amine (20.0 g, 49 mmol), 4-fluoro-nitro-
benzene (5.23 g, 49 mmol), sodium hydride (1.18 g, 49 mmol), and
120 mL DMSO. The mixture was heated and stirred at 120 ꢀC for 24 h.
The reaction mixture was then cooled and poured into 1 L of meth-
anol. The yellow precipitate was collected by filtration and dried
under vacuum. The product was purified by silica gel column
chromatography (n-hexane:dichloromethane ¼ 2:1) resulting in
the nitro compound 1 16.3 g in a 63% yield; mp 150e151 ꢀC by DSC
(10 ꢀC/min).
IR (KBr) 1580, 1341 cmꢁ1 (NO2 stretch). 1H NMR (CDCl3):
d
(ppm) ¼ 1.70 (s,12H, Hd); 6.97e6.99 (d, 2H, Hh, J ¼ 10.0 Hz); 7.04e7.05
(d, 4H, Hf, J ¼ 5.0 Hz); 7.05e7.07 (d, 2H, Hg, J ¼ 10.0 Hz); 7.15e7.17 (d,
4H, He, J ¼ 10.0 Hz); 7.19e7.20 (d, 4H, Hi, J ¼ 5.0 Hz); 7.20e7.21 (m, 2H,
Ha); 7.28e7.29 (d, 4H, Hc, J ¼ 5.0 Hz); 7.30e7.31 (d, 4H, Hb, J ¼ 5.0 Hz);