Vol. 32, No. 6 (2020)
Novel Mixed Complexes Derived from Benzoimidazolphenylethanamine and 4-(Benzoimidazol-2-yl)aniline 1267
In addition, 4-(benzoimidazol-2-yl) aniline [39,40] is an
efficient intermediates to synthesized a target that have a many
biological activities and have been described as heparanase
inhibitors [41], suppress key markers of allergy [42]. The
insertion of metals into molecular architectures to develop new
complexes containing benzimidazole nucleus has been widely
described in the literature [43-47]. It has been reported that
the presence of metal ions in the complexes manifests generally
a better therapeutic efficacy [48,49], similarly affecting their
physico-chemical properties [50,51].
In present work, our intention was take account of previ-
ously mentioned properties of antibacterial ligands, by grouping
the two motifs in one molecule and combining their properties.
Here, we present a new way to increase the effectiveness of
biologically active molecules. Herein, the synthesis and charac-
terization of some complexes of cadmium(II), copper(II), tin(II)
and nickel(II) from 4-(benzimidazole-2-yl)aniline (PBA) and
benzoimidazolphenylethanamine (BPE), which could prove
be efficacious antibacterial agents.
The reacting mixture was gradually heated and the temperature
was maintained at 85 ºC for 9 h under magnetic stirring to obtain
a solution which was allowed to cool overnight. The mixture
was filtered and washed with ethanol and then dried to afford
1
benzoimidazol phenylethanamine (BPE) in 97% yield. H NMR
(400 MHz, DMSO-d
(d, 2H, Ar-H), 7.57-7.55 (m, 2H, Ar-H), 7.24-7.21 (m, 5H, Ar-H
benzyl), 5.14-5.12 (d, 1H, NH -CH), 4.22-4.17 (m, 1H, CH),
3.12-3.08 (dd, 1H), 3.03-2.98 (dd, 1H). C NMR (100 MHz,
DMSO-d
6
, 400 MHz) δ: 8.23 (s, 1H, NH), 7.63-7.61
2
13
6
) δ: 143.9, 136.6, 134.9, 129.8 (2CH arom), 129.6
(2CH arom), 128.8 (2CH arom), 127.5, 127.2 (2CH arom),
119.5, 56.5, 39.0, 21.7. δmax (nm) = 260, 274, 305. IR (KBr,
-
1
ν
max, cm ): 3459, 3361 (N-H of NH ), 3209 (N-H), 3022 (C-H),
2
1615 (C=N), 1575 (C=C), 749 (Ar-H).
Synthesis of cadmium complex [Cd(PBA)(BPE)I ] (1):
2
To a solution of cadmium iodide 3.08 g, (8.4 mmol) in 30 mL
ethanol was added 1.75 g (8.4 mmol) of PBA in 30 mL ethanol.
The reaction mixture was stirred at room temperature for 30
min and then a solution of BPE (2 g, 8.4 mmL in 30 mL water)
was added to mixture and heated at 100 ºC for 13 h. The progress
of reaction was controlled with TLC (DMF/water: 50/50). At
the end of reaction, the reaction mixture was cooled, filtered
and the residue washed with ethanol followed by DMF to obtain
a beige precipitate.Yield: 80%, m.p.: 265 ºC, m.f.: C H N CdI ,
EXPERIMENTAL
FT-IR spectroscopy was recorded using Thermo-Nicolet-
6
700 FT-IR spectrometer by the KBr disc technique in the
-1
28
26
6
2
wavenumber range of 4000-400 cm . Electronic absorption
spectral were carried out in DMSO on a UV-2102 PC Shimadzu
spectrophotometer using 1 cm matched quartz cell in the wave-
-1
UV-vis (DMSO); λmax [nm]: 274 . IR (KBr, νmax, cm ): 3408 (m),
322 (m), 3243 (m), 3028 (m), 1608 (s), 1581 (s), 1495 (s),
1454 (m), 1384 (s), 1321 (m), 1102 (m), 1074 (m), 1002 (m),
3
1
13
length range 200-900 nm. The H & C-NMR were recorded
on Bruker NMR at 400 MHz and 100 MHz, respectively. The
chemical shifts were measured with reference to TMS as internal
standard in deuteriated DMSO as the solvent. Simultaneous
TGA and DTA analyses were performed employing a Shimadzu
DTG-60 instrument using a heating rate of 10 ºC/min in air
9
5
97 (m), 847 (s), 776 (m), 745 (m), 698 (m), 604 (m), 556 (m),
24 (m), 504 (m), 468 (m).
Synthesis of tin complex [Sn(PBA)(BPE)Cl ] (2): To a
2
solution of stannous chloride 1.6 g, (8.4 mmol) in 30 mL water
was added 1.75g (8.4 mmol) of PBA in 30mL ethanol. The
reaction mixture was stirred at room temperature for 30 min
and then a solution of BPE (2 g, 8.4 mmol in 30 mL water) was
added to mixture and heated at 100 ºC for 14 h. The progress
of reaction was controlled with TLC (DMF/water: 50/50). At
the end of reaction, the reaction mixture was cooled, diluted
with ethanol (40 mL), filtered and washed with ethanol and
then with DMF to obtain a red precipitate. Yield: 85%, m.p.:
atmosphere. The average samples weight was 10 mg α-Al
O
2 3
was used as a reference material in the DTA measurements.
The X-ray powder diffraction patterns of the compounds were
recorded an XRD diffractometer Model PW 1710 control unit
the (Philips). The anode material was CuKα (λ = 1.54180 Å),
40 K.V 30 M.A Optics:Automatic divergence slit.All reagents
employed in the synthesis of different complexes were comm-
ercially available amd used without further purification.
Synthesis of 4-benzoimidazolaniline (PBA) L1:A mixture
of o-phenylenediamine (0.54 g, 5 mmol) and 4-aminobenzoic
acid (0.95 g, 7 mmol) was added to 10 mL of toluene. The
reaction mixture was gradually heated and the temperature was
maintained at 85 ºC for 9 h under magnetic stirring to obtain a
solution, which was allowed to cool overnight. The mixture
was filtered and washed with ether and then dried to afford
2
3
1
30 ºC; m.f.: C28
H
26
N
6
SnCl . UV-vis (DMSO); λmax (nm): 280,
2
-1
10, 430. IR (KBr, νmax, cm ): 3443 (m), 3338 (m), 3224(m),
601 (s), 1567 (s), 1497 (s), 1411 (m), 1320 (s), 1236 (s), 1168
(
(
s), 1110 (s), 1069 (s), 849 (s), 744 (m), 607 (m) 498 (m), 434
m).
Synthesis of nickel complex [Ni(PBA)(BPE)Cl
a solution of nickel chloride hexahydrate 2 g, (8.4 mmol) in
0 mL water was added 1.75g (8.4 mmol) of PBA in 30 mL of
2
] (3): To
3
ethanol. The reaction mixture was stirred at room temperature
for 30 min and then a solution of BPE (2 g, 8.4 mml in 30 mL
water) was added to mixture and heated at 100 ºC for 15 h.
The progress of reaction was controlled with TLC (DMF/water:
4
-benzoimidazolaniline (PBA) in 82 % yield. m.p.: 235-237
-1
ºC, IR (KBr, νmax, cm ): 3430 (NH benzim); 3350, 3217 (NH
aniline); 3061 (CH=C); 1629 (C=N); 1605 (C=C). λmax (nm)
=
2
1
300. H NMR (DMSO-d
6
, 400 MHz) δ: 5.58 (s, NH ), 6.63
2
50/50).At the end of reaction, the reaction mixture was cooled,
(
d, 2H, aniline), 7.08 (m, 2H, benzim), 7.46 (m, 2H, benzim),
13
filtered and the residue washed with ethanol and then with DMF
to obtain a grey precipitate. Yield: 82%, m.p.: 345 ºC; m.f.
7.79 (d, 2H, aniline), 12.46 (br, NH benzim). C NMR (100 MHz,
DMSO-d ) δ: 113.05, 114.14, 123.50, 129.32, 135.78, 151.59,
6
C
28
-
H
26
N
6
NiCl
cm ): 3390 (m), 3351 (m), 3218 (m), 3050 (m), 1589 (m), 1496
s), 1452 (s), 1396 (s), 1336 (s), 1140 (m), 1060 (s), 817 (s), 765
s), 747 (m), 725 (m), 655 (s), 597 (m), 544 (m), 479 (s).
2
; UV-vis (DMSO); λmax (nm): 272. IR (KBr, νmax,
1
52.68.
Synthesis of benzoimidazolphenylethanamine (BPE)
1
(
(
L2: A mixture of o-phenylenediamine (0.54 g, 5mmol) and
L-phenylalanine (1.16 g, 7mmol) was added to 10 mL toluene.