M. Ghaemy, S.M. Amini Nasab / Reactive & Functional Polymers 70 (2010) 306–313
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(%) for C57H46N6O2: C, 80.82; H, 5.43; N, 9.92. Found: C, 80.83; H,
5.75; N, 9.72.
2. Experimental section
2.1. Materials
2.3. Synthesis of polyamides (Scheme 2)
All starting materials including the dicarboxylic acids, such as
pyridine-2, 6-dicarboxylic acid, terephthalic acid, isophthalic acid,
adipic acid, sebacic acid, and other reagents, were purchased from
either Merck or Fluka. N-Methyl-2 pyrrolidinone (NMP) and pyri-
dine (Py) were purified by distillation under reduced pressure over
calcium hydride and stored over 4-Å molecular sieves. Lithium
chloride (LiCl) was dried for 10 h at 180 °C under vacuum. All other
reagents and solvents were used as received.
The following general procedure was used for the preparation of
all of the polyamides. The diamine (III) (1 mmol), dicarboxylic acid
(1 mmol), and lithium chloride (0.6 g) were dissolved in a mixture
of pyridine (1 mL), TPP (1.2 mmol), and NMP (8 mL) in a three-
necked flask equipped with a condenser, a mechanical stir and a
nitrogen gas inlet tube. The mixture was heated at 110 °C for
14 h with stirring under a dry N2 atmosphere. The system was then
cooled to room temperature and the solution was poured into
300 mL of methanol. The precipitate was filtered and washed with
hot water. For further purification, all of the polyamides were ex-
tracted in methanol for 24 h. The extracted polyamides were then
filtered and dried at 100 °C under vacuum. The inherent viscosities
of the polymers in NMP were in the range of 0.95–1.2 dL/g, as mea-
sured at a concentration 0.5 g/dL at 25 °C.
2.2. Synthesis of monomer (Scheme 1)
2.2.1. 2-(2-chloro-5-nitrophenyl)-4,5-diphenyl-1H-imidazole (I)
A mixture of 1.86 g (0.01 mol) 2-chloro-5-nitrobenzaldehyde,
2.1 g (0.01 mol) benzil, 5.39 g (0.07 mol) ammonium acetate, and
20 mL of glacial acetic acid was refluxed for 24 h in a 250 mL
round-bottomed two-necked flask equipped with a condenser, a
magnetic stir bar and a nitrogen gas inlet tube. Upon cooling, the
precipitated white solid was collected by filtration and washed
with ethanol and water. Yellow crystals (3.55 g, yield of 95%) were
obtained with a melting point (mp) of 218–220 °C. Fourier trans-
form infrared (FT-IR) (KBr, cmꢀ1): 3453 (NH), 3124 (CAH aro-
matic), 1684 (C@N), 1532 and 1345 (NO2). Elemental analysis
calculated (Anal. Calcd.) (%) for C21H14ClN3O2: C, 67.20; H, 3.73;
N, 11.20. Found: C, 67.00; H, 3.65; N, 11.35.
PA-a: Yield: 86%, FT-IR (KBr, cmꢀ1): 3442 (NH imidazole), 3060
(CAH aromatic), 2973(CAH aliphatic), 1684 (C@O amide), 1588
(C@N imidazole), 1492 (C@C), 1370 (CAN), 1224 (CAO).1H NMR
(DMSO-d6): d 12.36 (s-2H), 10.68 (s-2H), 6.99–8.75 (m-37H), 1.72
(s-6H). Anal. Calcd. C, 78.86; H, 4.75; N, 9.91. Found C, 78.18; H,
4.95; N, 9.61.
PA-b: Yield: 90%, FT-IR (KBr, cmꢀ1): 3428 (NH imidazole), 3049
(CAH aromatic), 2975 (CAH aliphatic), 1668 (C@O amide), 1607
(C@N imidazole), 1498 (C@C), 1370 (CAN), 1235 (CAO). 1H NMR
(DMSO-d6):
d
12.21(s-2H), 10.61(s-2H), 6.95–8.28(m-38H),
1.61(s-6H). Anal. Calcd. C, 79.92; H, 4.92; N, 8.61. Found C, 79.32;
H, 4.90; N, 8.31.
2.2.2. 2-(2-(4-(2-(4-(4-nitro-2-(4,5-diphenyl-1H-imidazol-2-yl)
phenoxy) phenyl) propan-2-yl) phenoxy) -5-nitrophenyl)-4,5-
diphenyl-1H-imidazole (II)
PA-c: Yield: 85%, FT-IR (KBr, cmꢀ1): 3362 (NH imidazole), 3059
(CAH aromatic), 2968 (CAH aliphatic), 1664 (C@O amide), 1610
(C@N imidazole), 1487 (C@C), 1370 (CAN), 1229 (CAO). 1H NMR
(DMSO-d6): d 12.11 (s-2H), 10.56 (s-2H), 7.15–8.61 (m-38H), 1.65
(s-6H). Anal. Calcd. C, 79.92; H, 4.92; N, 8.61. Found C, 79.45; H,
4.65; N, 8.51
A mixture of 2.28 g (10 mmol) Bisphenol A, 7.5 g (20 mmol) (I),
2.76 g (20 mmol) anhydrous potassium carbonate in 20 mL of dry
DMAc was refluxed at 140 °C for 12 h in a 250 mL round-bottomed
two-necked flask equipped with a condenser, a magnetic stir bar
and a nitrogen gas inlet tube. After cooling, the mixture was
poured into water and the precipitate was collected by filtration
and recrystallized from ethanol. The yield of the reaction was
96% (8.7 g); mp 210–212 °C. FT-IR (KBr) at cmꢀ1: 3443 (NH),
3059 and 2963 (CAH aromatic and aliphatic), 1603 (C@N), 1537
and 1345 (NO2). Anal. Calcd. (%) for C57H42N6O6: C, 75.47; H,
4.63; N, 9.27. Found: C, 75.52; H, 4.6; N, 9.33.
PA-d: Yield: 95%, FT-IR (KBr, cmꢀ1): 3447 (NH imidazole), 3044
(CAH aromatic), 2953 (CAH aliphatic), 1669 (C@O amide), 1603
(C@N imidazole), 1482 (C@C), 1370 (CAN), 1225 (CAO). 1H NMR
(DMSO-d6): d 12.11(s-2H), 10.56(s-2H), 6.93–9.38 (m-34H), 2.16
(t-4H), 1.63 (s-6H), 1.55 (m-4H). Anal. Calcd. C, 78.91; H, 5.63; N,
8.77. Found C, 78.23; H, 5.82; N, 8.65.
PA-e: Yield: 91%,FT-IR (KBr, cmꢀ1): 3452 (NH imidazole), 3054
(CAH aromatic), 2917 (CAH aliphatic), 1665 (C@O amide), 1608
(C@N imidazole), 1485 (C@C), 1375 (CAN), 1219(CAO). 1H NMR
(DMSO-d6): d 12.11 (s-2H), 10.56 (s-2H), 6.99–8.27 (m-34H), 2.18
(t-4H), 1.65 (s-6H), 1.28 (m-12H). Anal. Calcd. C, 79.44; H, 5.93;
N, 8.30. Found C, 79.29; H, 5.42; N, 8.36.
2.2.3. 4-(4-(2-(4-(4-amino-2-(4, 5-diphenyl-1H-imidazol-2-yl)
phenoxy) phenyl) propan-2-yl) phenoxy)-3-(4,5-diphenyl-1H-
imidazol-2-yl)benzenamine (III)
In a 250 mL round-bottomed three-necked flask equipped with
a dropping funnel, a reflux condenser and a magnetic stir bar,
9.06 g (0.01 mol) (II) and 0.2 g of 10% Pd/C were dispersed in
80 mL ethanol. The suspension was heated to reflux, and 8 mL of
hydrazine monohydrate was added slowly to the mixture. After
an additional 5 h of reflux, the solution was filtered hot to remove
the Pd/C. Upon cooling of the filtrate, white crystals precipitate,
which were collected by filtration and dried under vacuum at
80 °C. The yield was 88% (7.5 g); mp 150–152 °C. FT-IR (KBr) at
cmꢀ1: 3433 and 3373 (NH2), 3442 (NH imidazole), and 1219
(CAO). 1H NMR (500 MHz, DMSO-d6): d 1.54 (s, 6H), 5.25 (s, 4H),
6.64–6.66 (dd, 2H, J = 8.35 Hz), 6.79–6.86 (m, 6H, J = 8.35 Hz), 7–
7.14 (t, 4H, J = 8.35 Hz), 7.20–7.24 (t, 2H, J = 8.35 Hz), 7.25–7.28
2.4. Preparation of MWCNT suspension and modified working
electrode (CPE)
To eliminate metal oxide catalysts within the nanotubes,
MWCNTs were refluxed in 2.0 M HNO3 for 15 h, and then washed
thoroughly with twice-distilled water and dried at room temper-
ature [34]. The purified MWCNTs were dispersed in acetonitrile
(0.1 mg MCNTs/10 mL) by ultrasonic agitation to obtain a relative
stable suspension. The modified electrode was made by mixing
(w/w) of 3% polymer (or 3% monomer), 5% MWCNT, and graphite
powder in ether and hand mixing with a mortar and pestle. The
solvent was evaporated by stirring. A 1:1 (w/w) mixture of the
above modified electrode and paraffin was blended by hand mix-
ing until a uniformly wetted paste was obtained. The resulting
paste was inserted in the bottom of a glass tube (with internal ra-
dius and length of 1.0 mm and 10 cm, respectively). The electrical
(t, 4H, J = 8.75), 7.30–7.37 (m, 12H),
d
7.46–7.49(t, 4H,
J = 8.75 Hz), d 11.90 (s, 2H). 13C NMR (500 MHz, DMSO-d6): d
31.59, 42.29, 114.79, 115.52, 116.37, 116.85, 122.80, 124.09,
127.27, 127.88, 128.17, 128.40, 128.94, 129.03, 129.40, 131.93,
136.09, 137.32, 143.37, 143.96, 144.82, 146.41, 157.01. Anal. Calcd.