INORGANIC AND NANO-METAL CHEMISTRY
3
1
1
1
1
28.4 (C ), 129.3 (C ), 132.0 (C ), 132.6 (C ), 134.2 (C ),
10 11 18 4 12
38.5 (C ), 139.7 (C ), 141.7 (C ), 146.4 (C ), 151.6 (C ),
2
0
5
3
2
21
ꢁ
1
57,6 (C ), 160.1 (C ) ppm. IR (KBr): 1647 cm (CH ¼ N),
8
ꢁ
17
ꢁ1
1
þ
357 cm
1572 cm
(NO2Ar). MS (m/z) 475 (M þ2).
Anal. Calcd for C H ClN O (473.9): C, 63.36; H, 4.25; N,
25
20
5 3
1
4.78. Found: C, 62.88; H, 4.85; N, 14.41.
General procedure for the synthesis of complexes 8a,b
from ligands 7a,b
Pd(II) chloride (0.17 gr, 1 mmol) was added to the yellow
color solution of ligand 7a,b (7a: 0.88 g or 7 b: 0.94 g;
2
1
mmol) in aqueous MeOH solution (20 ml, MeOH, H O,
0:90). The solution color was changed to dark green. The
2
Figure 1. The absorption spectra of the ligands 7a,b and Pd(II) complexes 8a,b
in MeOH solution (2 ꢂ 10ꢁ M).
reaction was continued for 6 h at ambient temperature. By
the removing solvent, the complex was isolated and washed
with the cold methanol (10 ml) and then distilled
water (10 ml).
4
[
Pd(L1) ] Cl (8a): was obtained as a dark green powder.
2 2
ꢀ
1
mp > 300 C (decomp). H NMR (DMSO-d6): d 0.89 (t,
J ¼ 7.5 Hz, 6H, CH ), 1.87–1.98 (m, 4H, CH ), 3.81
3
2
(
OMeAr) 4.37 (t, J ¼ 7.5 Hz, 4H, NCH ), 7.18 (d, J ¼ 9.0 Hz,
2
4
8
1
H, Ar H), 7.72–7.92 (m, 10H, Ar H), 8.31 (s, 2H, Ar H),
.96 (d, J ¼ 9.0 Hz, 4H, Ar H), 9.08 (s, 2H, CH). IR (KBr):
ꢁ
1
ꢁ1
019 cm , 1234 cm (OMeAr), ESI-MS (þ) m/z (%): 996
2
þ
[
Pd(L2)2] . Anal. Calcd for C H Cl N O Pd (1067.1): C,
50 42 4 8 4
5
6. 27; H, 3.97; N, 10.50; Pd, 9.97. Found: C, 55.91; H, 3.45;
N, 9.78; Pd, 9.32.
Pd(L2) ] Cl (8b): was obtained as a dark green powder.
[
2
2
ꢀ
ꢁ1
ꢁ1
mp > 300 C (decomp). IR (KBr): 1211 cm , 1241 cm
Figure 2. The fluorescence emission spectra of the ligands 7a,b and Pd(II) com-
plexes 8a,b in MeOH solution (1 ꢂ 10ꢁ M).
2þ
(
NO2Ar), ESI-MS (þ) m/z (%): 1054 [Pd(L1)2]
.
5
Anal. Calcd for C H Cl N O Pd (1125.1): C, 53.37; H,
50
40
4 10 6
3
.58; N, 12.45; Pd, 9.46. Found: C, 52.90; H, 3.19; N, 11.96;
Table 1. Spectroscopic data for the new compounds 7a,b and 8a,b at 298 K.
Pd, 8.89.
Dye
abs (nm)
7a
7b
8a
8b
a
k
380
4.80
610
0.44
330
4.97
625
0.56
770
3.60
600
0.29
770
ꢁ
3
ꢁ1 ꢁ1
ꢁ1 b
e ꢂ 10 [(mol L
)
cm
]
3.60 Results and discussion
c
k
U
flu (nm)
F
600
d
0.21 Synthesis and structure of the novel ligands 7a,b and
aWavelengths of maximum absorbance (kabs).
bExtinction coefficient.
complexes 8a,b
cWavelengths of fluorescence emission (kflu) with excitation at 400 nm.
dFluorescence quantum yield.
According to the following methods, we have prepared two
novel heterocyclic Schiff-base ligands in five steps. At first,
1
-alkyl-5-nitro-1H-benzimidazoles (1a,b) were prepared
ꢁ
1
ꢁ1
ꢁ1
(
(
KBr): 1659 cm
(CH ¼ N), 1035 cm
1252 cm
through the reaction of 1-bromobutane or 1-bromopropane
with 5-nitro-1H-benzimidazole in the presence of DMF and
KOH.
zo[4 ,5 :3,4]benzo[1,2-c]isoxazoles (3a,b) were synthesized
with the interaction of 1-alkyl-5-nitro-1H-benzimidazoles
þ
OMeAr). MS (m/z) 415 (M þ2). Anal. Calcd for
[
42]
C H ClN O (413.8): C, 67.49; H, 4.76; N, 12.59. Found:
2
5
21
4
2
At second, 3-alkyl-8-(4-chlorophenyl)-3H-imida-
C, 66.93; H, 4.52; N, 12.03.
E)-3-butyl-8-(4-chlorophenyl)-N-(4-nitrobenzylidene)-3H-
imidazo[4 ,5 :3,4]benzo[1,2-c]isoxazol-5-amine (7b, L2) was
obtained as a yellow powder. m.p: 189–193 C; yield: 75%.
H NMR (CDCl ): d 0.87 (t, J ¼ 7.5 Hz, 3H, CH ), 1.28–1.41
0
0
(
0
0
(1a,b) and (4-chlorophenyl)acetonitrile (2) in the presence
ꢀ
[43]
of basic methanol solution (70 ml).
chlorophenyl)-5-nitro-3H-imidazo[4 ,5 :3,4]benzo[1,2-c]iso-
At third, 3-alkyl-8-(4-
1
0 0
3
3
(
2
m, 2H, CH ), 1.72–1.79 (m, 2H, CH ), 4.17 (t, J ¼ 7.5 Hz, xazoles (4a,b) were prepared in well yield through regiose-
2
2
H, NCH ), 7.58 (d, J ¼ 8.4 Hz, 2H, Ar H), 7.79 (d, lective nitration of compound 3a,b in the presence of
[44]
2
J ¼ 8.7 Hz, 2H, Ar H), 7.53 (s, 1H, Ar H), 8.16 (d, sulfuric acid and potassium nitrate.
At forth, 8-(4-chloro-
0
0
J ¼ 8.4 Hz, 2H, Ar H), 8.34 (s, 1H, Ar H), 8.37 (d, phenyl)-3-alkyl-3H-imidazo[4 ,5 :3,4]benzo[1,2-c]isoxazol-5-
13
[45]
J ¼ 8.7 Hz, 2H, Ar H), 8.96 (s, 1H, CH ¼ N) ppm; C NMR amines (5a,b)
were obtained in excellent yield through
CDCl ): d 13.2 (C ), 20.7 (C ), 32.6 (C ), 47.9 (C ), the reduction of compounds 4a,b by SnCl in the presence
(
3
16
15
14
13
2
1
09.4 (C ), 115.7 (C ), 116.2 (C ), 122.0 (C ), 128.1 (C ), of ethanol (20 ml). At final, by the reaction of amines 5a,b
7 1 6 20 9