DMSO were recorded for each compound. Then an oxidizing
solution containing ca. 3 ꢂ 10ꢀ4 M of (NH4)2S2O8 in 0.1 M
HCl was added dropwise. The absorption spectra were regis-
tered after the addition of each drop of oxidizing agent.
Experimental
General methods and materials
1H and 13C NMR spectra were recorded on a Varian Mercury
(400 and 100 MHz) spectrometer and referenced with respect
to TMS and solvent, respectively. IR spectra were recorded on
Bio-RAD FTS-165 spectrometer using KBr pellets. UV-Vis-
NIR spectra were registered using a Lambda 2 (Perkin–Elmer)
spectrometer in the spectral range 200–1100 nm. Mass spectra
were measured by the EI method on a AMD 604 mass spectro-
meter. All compounds studied were subjected to elemental
analyses. C, H and N were determined by combustion analysis.
Characterization of synthesized compounds
N-(4-Nitrophenyl)-1,4-phenylenediamine (1). 0.11 g, 10%
yield, m.p. 206–208 1C. 1H NMR (400 MHz, DMSO-d6) d
8.89 (s, 1H), 8.00–7.98 (m, 2H), 6.91–6.89 (m, 2H), 6.76–6.74
(m, 2H), 6.61–6.59 (m, 2H), 5.09 (s, 2H). IR (cmꢀ1) 3457, 3372,
1624, 1592, 1523, 1515, 1496, 1464, 1299, 1254, 1176, 1112,
842, 833, 752. Anal. calcd for C12H11N3O2: C, 62.89; H, 4.80;
N, 18.34. Found: C, 62.39; H, 4.88; N, 17.85.
N-Phenyl-1,4-phenylenediamine,
4,40-diaminodiphenyla-
mine sulfate, triethylamine, dimethyl sulfoxide (DMSO), 4-
fluoronitrobenzene, ammonium persulfate and Sn powder were
purchased from Aldrich Chemical Co. Acetone, dichloro-
methane, ethyl acetate, sodium pyrosulfite, HCl, KOH, NaOH
were purchased from POCh (Poland). N-Phenyl-1,4-phenyle-
nediamine was crystallized from water and dried over KOH in
a vacuum desiccator. Triethylamine was dried over KOH.
DMSO was stored over thermally activated 4 A molecular
sieves. 4-Fluoronitrobenzene, Sn powder, the oxidant and the
solvents were used as supplied.
N,N-Di(4-nitrophenyl)-1,4-phenylenediamine (2). 1.14 g, 65%
yield, m.p. 232–234 1C. 1H NMR (400 MHz, DMSO-d6) d 8.15
–8.13 (m, 4H), 7.17–7.14 (m, 4H), 6.91–6.89 (m, 2H), 6.65–6.63
(m, 2H), 5.43 (s, 2H). 13C NMR (100 MHz, DMSO-d6) d 152.0,
148.5, 141.3, 132.0, 128.8, 125.5, 121.3, 115.2. IR (cmꢀ1) 3552,
3474, 3383, 3072, 1618, 1579, 1494, 1341, 1326, 1308, 1278,
1180, 1110, 848, 751. Anal. calcd for C18H14N4O4: C, 61.71; H,
4.00; N, 16.00. Found: C, 61.85; H, 4.31; N, 15.56.
Syntheses
1
Tris(4-Aminophenyl)amine (3). 0.45 g, 78% yield, H NMR
Synthesis of 4,40-diaminodiphenylamine. 4,40-Diaminodiphe-
nylamine sulfate (ca. 1.2 g) was dissolved in 50 ml of 1%wt
KOH solution; 0.6 g of sodium pyrosulfite, Na2S2O5, were
added to the solution and the mixture was boiled for 15 min,
then filtered and crystallized. White crystals were dried over
KOH in a vacuum desiccator. M.p.158–160 1C. 1H NMR (400
MHz, DMSO-d6) d 6.76 (s, 1H), 6.63 (s, 4H), 6.45 (m, 4H), 4.46
(s, 4H). IR (cmꢀ1) 3409, 3390, 3034, 1612, 1515, 1312, 1275,
823. Anal. calcd for C12H13N3 C, 72.36; H, 6.53; N, 21.11.
Found: C, 69.68; H, 6.50; N, 20.39.
(400 MHz, DMSO-d6) d 6.43–6.41 (m, 12H), 5.0–4.1 (s, 6H).
13C NMR (100 MHz, DMSO-d6) d 127.2, 114.9, 105.6. IR
(cmꢀ1) 3553, 3474, 3383, 1618, 1602, 1579, 1494, 1308, 1278,
1110, 848, 751. Anal. calcd for C18H18N4: C, 74.48; H, 6.21; N,
19.31. Found: C, 73.60; H, 6.15; N, 19.04. MS m/z ¼ 290.4.
N,N-Di(4-nitrophenyl)-N0,N0-di(4-aminopheny)-1,4-phenyle-
1
nediamine (4). 0.53 g, 20% yield, m.p. 245–248 1C. H NMR
(400 MHz, DMSO-d6) d 8.16–8.14 (m, 4H), 7.18–7.16 (m, 4H),
6.96–6.94 (m, 2H), 6.90–6.88 (m, 4H), 6.61–6.59 (m, 2H), 6.56–
6.54 (m, 4H), 5.05 (s, 4H). IR (cmꢀ1) 3448, 3364, 1603, 1580,
1502, 1344, 1307, 1278, 1265, 1111, 842, 831, 750, 696. Anal.
calcd for C30H24N6O4 ꢁ (H2O)1.14: C, 65.16; H, 4.76; N, 15.20.
Found: C, 64.35; H, 4.38; N, 14.54.
General procedure for the substitution reactions. Aromatic
amine (5 mmol) and 4-fluoronitrobenzene (10 mmol for reac-
tions in Scheme 1, 2, 3 and 5 mmol for reactions in Scheme 4)
were dissolved in 15 ml of DMSO. K2CO3 (20 mmol for
reactions in Scheme 1 and 2) or triethylamine (10 mmol for
reactions in Scheme 3 and 5 mmol for reactions in Scheme 4)
was added to the solution and the mixture was stirred and
heated at 90 1C for 3 days under an argon atmosphere to avoid
oxidation of the amine. Then the solution was allowed to cool
to room temperature and poured into 200 ml of distilled water.
The brown-orange solid was precipitated, washed several times
with distilled water and dried in air. The crude product was
purified by a liquid chromatography.
Branched heptamer (5). 2.08 g, 54% yield, 1H NMR (400
MHz, DMSO-d6) d 8.18–8.16 (m, 8H), 7.22–7.20 (m, 8H), 7.15
–7.13 (m, 4H), 7.07–7.04 (m, 4H), 6.95–6.93 (m, 2H), 6.63–6.61
(m, 2H), 5.20 (s, 2H). IR (cmꢀ1) 3465, 3381, 1603, 1581, 1503,
1494, 1344, 1307, 1280, 1266, 1178, 1111, 843, 831, 750, 695.
Anal. calcd for C42H30N8O8 ꢁ (H2O)2.34: C, 61.76; H, 4.25; N,
13.75. Found: C, 61.09; H, 4.03; N, 13.07.
N-(4-Nitrophenyl)-N0-(4-aminophenyl)-1,4-phenylenediamine
General procedure for the reduction of nitro compounds. The
nitro compound (2 mmol) was stirred with 4 ml of 37% HCl
under an argon atmosphere for 15 min at room temperature.
Tin powder (29.0 mmol for reductions in Scheme 3 and 15
mmol for reductions in Scheme 4) and 37% HCl (20 ml) were
added in portions and the mixture was refluxed for ca.3 h until
a yellowish white precipitate was formed. After cooling to
room temperature 10 ml of 20%wt NaOH solution and then
NaOH granules were slowly added with constant stirring. The
pH of the mixture was adjusted to 12. The white precipitate
was filtered under an argon atmosphere and the product was
washed several times with 20%wt NaOH solution, then with
distilled water to pH ¼ 7. The greyish-white powder was dried
over KOH in a vacuum desiccator.
1
(6). 0.18 g, 11% yield, m.p. 178–181 1C. H NMR (400 MHz,
DMSO-d6) d 9.00 (s, 1H), 8.02–7.99 (m, 2H), 7.55 (s, 1H), 7.00
–6.98 (m, 2H), 6.84–6.79 (m, 6H), 6.55–6.52 (m, 2H), 4.78 (s,
2H). IR (cmꢀ1) 3401, 3329, 2969, 1600, 1514, 1501, 1470, 1334,
1307, 1262, 1186, 1115, 835, 813, 750. Anal. calcd for
C18H16N4O2: C, 67.50; H, 5.00; N, 17.50. Found: C, 66.85;
H, 4.70; N, 17.25.
N,N-Di(4-nitrophenyl)-N0-(4-aminophenyl)-1,4-phenylenedia-
mine (7). 1.5 g, 68% yield, m.p. 227–230 1C. 1H NMR (400
MHz, DMSO-d6) d 8.16–8.14 (m, 4H), 7.81 (s, 1H), 7.19–7.16
(m, 4H), 7.00–6.97 (m, 2H), 6.86–6.81 (m, 4H), 6.56–6.54 (m,
2H), 4.86 (s, 2H). IR (cmꢀ1) 3367, 3067, 1596, 1577, 1512,
1491, 1334, 1320, 1308, 1272, 1177, 1109, 829, 751. Anal. calcd
for C24H19N5O4: C, 65.31; H, 4.31; N, 15.87. Found: C, 64.00;
H, 4.22; N, 15.57.
General procedure for the oxidation of oligoanilines. The UV-
Vis-NIR spectra of ca. 5 ꢂ 10ꢀ5 M of the oligoaniline in
1236
N e w J . C h e m . , 2 0 0 4 , 2 8 , 1 2 3 5 – 1 2 4 3