F.A. Saad / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 128 (2014) 386–392
387
which elaborate their applications [2]. Chelating ligands with con-
jugated oxygen or nitrogen donor sites represent some of the most
important ligands in coordination chemistry and their metal com-
plexes are useful for homogenous catalysis, chemical vapor deposi-
tion, supramolecular chemistry, redox sensing, photophysics,
magnetic materials, and so on [3]. A distinguish biological activity
was recorded for most investigated complexes especially with the
presence of N, S and O heteroatom’s [4–14]. This research is con-
sidered a continuation of my work, previously, I have contributed
in works nearby this research point [15,16]. The aim of the work
is based on view of the significant role played by the metal com-
plexes of pyridine moiety. I have motivated to prepare new com-
plexes derived from pyridine nucleus, which may serve in
different fields. The chemistry of the complexes are elaborately
investigated by all possible tools. Concerning with the crystal
structures of the complexes have been reported by single crystal
X-ray diffraction to justify on the geometry isolated. Moreover, I
have studied the electrochemical behavior of these complexes.
O
S
N
H
N
H
N
2
Fig. 1. 1-Benzoyl-3-(4-methylpyridin-2-yl) thiourea, H L ligand.
Recrystallisation from hot acetonitrile yielded monoclinic crystals
(Fig. 1).
Characterization of H
2
L ligand
Significant IR data as fellow:
t
NH at 3285 cmꢁ1;
tC@O at 1677;
t
(400 MHz,CDCl ): 13.0(1H,s,NH );
3
1
2
IV
d(NH) at 1606; d(NH) at 1556;
C@N at 1519 and t C@S at
ꢁ1
1
2
8
9
3
1
31 cm
.
H NMR (Fig. 2) d
.04(1H,s,NH ); 8.57(2H,d,Py); 7.86(2H,d,Py); 6.93–7.49(5H,m,Ar);
H
Experimental
1
1
3
.66(3H,s,CH
77.0, 166.6, 151.2–148.2, 133–116, 77.2 and 21.5 for pyridine, ben-
group. Accurate MS (Fig. 3) (m/z) = M+ 271.0776
calcd. 271.34) of C14 OS and the base peak (100% intensity),
2.95 for an organic part fragment. UV/Vis from 230 to 1100 nm
3 2 C 3
); 2.36(H O of solvent). C NMR d (250 MHz, CDCl ):
General and instrumentation
zene and CH
3
All reagents and solvents were purchased from commercial
sources and used as it is without previous purification. Single crys-
tal X-ray data was collected on a Bruker/Nonius Kappa CCD diffrac-
(
8
13 3
H N
ꢁ
1
ꢁ1
3
in CH CN, kmax, nm (eM, M cm ): CT bands are, 308(171433.4)
tometer using graphite monochromated Mo
Ka radiation
and 267 (292016.5).
Procedure for the synthesis of complexes H
(k = 0.71073 Å), equipped with an Oxford Cryostream cooling
apparatus. NMR spectra were measured on a Bruker AM 250–400
or Bruker Av-500 Plus FT-NMR spectrometer. Residual signals of
solvent were used for reference for 1H and C NMR. For infrared
spectra, each compound was pressed into a disk with an excess
of dried KBr and measured on a Jasco 660 FT-IR spectrophotometer
13
solvent
O $
According to this equation;
½MðH LÞ ðAcNÞ ꢃðClO
2H
2
L þ MðClO
4
Þ ꢂ 6H
2
2
2
2
2
4
2
, the ligand (1 equivalent, typically, 50 mg
Þ
ꢁ1
(
0.1845 mmol) was dissolved in a minimum amount of acetonitrile
at the range 400–4000 cm . Electrospray (ES) and high-resolution
HR) mass spectra were measured on a Waters LCT Premier XE (oa-
(
(3 ml). The solutions were warmed to 60 °C to ensure that the li-
gand fully dissolved. To this stirring solution, the metal perchlorate
(1 equivalent, 0.0225 and 0.0225 g of Ni and Co(II) salts, respec-
tively) dissolved in the same solvent and was added drop wise.
Recrystallisation of the complexes was carried out by using diethyl
ether, the yields are 89.97% and 67.30% for Ni and Co(II) complexes,
respectively.
TOF) mass spectrometer. UV–Vis absorption spectra were run in
HPLC grade acetonitrile (Fisher) and measured on a Jasco V-570
spectrophotometer from 230 to 1100 nm (optical path length
1
.0 cm). The cyclic voltammetry experiments were carried out
with an AUTOLAB PGSTAT12 potentiostat in conjunction with Gen-
eral Purpose Electrochemical System software (GPES version 4.7
for Windows) in a specially designed three-electrode glass cell
with a Teflon-coated cell cap. A Bioanalytical platinum working
electrode (model no. MF2013) with a 1.6 mm disk was used for
all experiments. The counter electrode was a platinum wire and
Warning, perchlorate salts are potentially explosive. Care should
be taken while handling such complexes.
13 3 2 3 2 4 2
Characterization of [Ni(C14H N OS) (CH CN) ](ClO ) complex
3
the reference electrode an Ag/AgNO electrode. To regain electro-
Green triclinic crystals of the complex were investigated: IR
ꢁ
1
1
chemical sensitivity and reproducibility the working electrode
was polished, with 600 grid emery paper, to a mirror surface and
then ultrasonicated. Prior to each experiment, the electrode was
washed with high performance liquid chromatography (HPLC)
data are;
t
NH at 3433 cm
d(NH) at 1532; C@N at 1491 and
1022(m) and 624(s) cm
; tC@O at 1662; d(NH) at 1623;
2
IV
ꢁ1
t
t
C@S at 759 cm
MAN and MAS at 463 and
357 cm , respectively. Accurate MS (Fig. 4) (m/z) = 629.55(10),
base peak at 599.08(100%) for C28 Ni. UV/Vis in CH CN,
M, M cm ), d–d transitions at; 589(2657.4) and
. tClAO at
ꢁ
1
;
t
t
ꢁ1
grade, CH
3
CN and dried in air for about 15 min. A 0.1 M [Bu
4
NꢂBF
6
]
H
25
N
6
O
S
2 2
3
ꢁ
1
ꢁ1
(
TBATFB) solution in CH
3
CN was used as supporting electrolyte. In
kmax, nm (e
ꢁ1
ꢁ1
all cases, ferrocene was used as an internal reference. Solutions
were degassed with nitrogen and a nitrogen atmosphere was
maintained over the solution during the experiment.
947.9 (3070.4). Dq, B and b are 1054.9 cm , 876.52 cm
and
0.842, respectively.
13 3 2 3 2 4 2
Characterization of [Co(C14H N OS) (CH CN) ](ClO )
Brown triclinic crystals of the complex (Fig. 5) were investi-
ꢁ
1
1
Synthesis of 1-benzoyl-3-(4-methylpyridin-2-yl) thiourea, H
2
L
gated: IR data are;
1
t
NH at 3431 cm
624; d(NH) at 1578; C@N at 1489 and
ClAO at 1020(m) and 624(s) cm
; tC@O at 1663; d(NH) at
2
IV
ꢁ1
t
t
C@S at 757 cm
MAN and MAS at 470
respectively. Accurate MS (Fig. 6) (m/
Co.
M, M cm ), d–d transitions at;
380(26526.5), 520(8122.4) and 1163(1126902). Dq, B and b are
.
ꢁ1
2
.0 g, 18.49 mmol of 4-methylpyridin-2-amine dissolved in ace-
t
;
t
t
ꢁ
1
tone (50 ml) and benzoyl isothiocyanate (2.48 ml, 18.49 mmol)
was added drop-wise. The mixture was heated up to 40 °C for
and 360 cm ,
25 6 2 2
z) = 690.16(10), base peak at 600.083(100%) for C28H N O S
ꢁ
1
ꢁ1
1
0 min then allowed to cool at room temperature. The solvent
3
UV/Vis in CH CN, kmax, nm (e
was removed under reduced pressure. Ether was used to precipi-
tate the product as a yellow powder (4.563 g, 91.07%, 16.83 mmol).
ꢁ1
ꢁ1
859.8 cm , 794.96 cm and 0.819, respectively.