Synthesis and characterization of metal complexes with NOS unsymmetrical tridentate Schiff base ligand. X-ray crystal structures determination of nickel(II) and copper(II) complexes

Article abstract of DOI:10.1016/j.poly.2016.08.021

A unsymmetrical tridentate NOS Schiff base ligand, 2-((2-(2-nitrophenylthio)phenylimino)methyl)phenol (HL) and its Mn(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes have been synthesized. These compounds have been characterized by different physico-chem

Full text of DOI:10.1016/j.poly.2016.08.021

Accepted Manuscript
Synthesis and characterization of metal complexes with NOS unsymmetrical
tridentate Schiff base ligand. X-ray crystal structures determination of nickel(II)
and copper(II) complexes
Ahmad Ali Dehghani-Firouzabadi, Morteza Sobhani, Behrouz Notash
PII:
S0277-5387(16)30380-1
DOI:
http://dx.doi.org/10.1016/j.poly.2016.08.021
POLY 12158
Reference:
To appear in:
Polyhedron
Received Date:
Revised Date:
Accepted Date:
21 June 2016
14 August 2016
16 August 2016
Please cite this article as: A. Ali Dehghani-Firouzabadi, M. Sobhani, B. Notash, Synthesis and characterization of
metal complexes with NOS unsymmetrical tridentate Schiff base ligand. X-ray crystal structures determination of
nickel(II) and copper(II) complexes, Polyhedron (2016), doi: http://dx.doi.org/10.1016/j.poly.2016.08.021
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Synthesis and characterization of metal complexes with NOS
unsymmetrical tridentate Schiff base ligand. X-ray crystal
structures determination of nickel(II) and copper(II) complexes
a,
∗
a
Ahmad Ali Dehghani-Firouzabadi , Morteza Sobhani , Behrouz Notash
b
a
Department of Chemistry, Faculty of Science, Yazd University, 89195-741 Yazd, Iran
b
Chemistry Department, Shahid Beheshti University, G. C., Evin, Tehran 1983963113, Iran
∗
Corresponding author: E-mail address: aadehghani@yazd.ac.ir (A.A.Dehghani-Firouzabadi)
1

Abstract
A
unsymmetrical
tridentate
NOS
Schiff
base
ligand,
2-((2-(2-
nitrophenylthio)phenylimino)methyl)phenol (HL) and its Mn(II), Ni(II), Cu(II), Zn(II) and
Cd(II) complexes have been synthesized. These compounds have been characterized by
different physico-chemical and spectroscopic techniques. The molecular structure of Cu(II)
and Ni(II) complexes are determined by single crystal X-ray diffraction technique. In Cu(II)
complex, two ligands coordinated through azomethine-N, thioether-S and phenolate-O
forming a mono-nuclear 6-coordinate distorted octahedral geometry around metal. However,
Ni(II) complex formed a mono-nuclear 4-coordinate distorted square planar geometry around
metal. In this complex, two ligands bonded through azomethine-N and phenolate-O and
occupied the vacant site of metal.
Keywords: NOS donor; Tridentate ligand; Unsymmetrical ligand; Schiff base complexes;
Thioether ligand.
1
. Introduction
Schiff bases have played a major role in the development of coordination chemistry
and the synthesis of Schiff bases is one the main areas of interest in the chemical composition
of biochemistry, material science, hydrometallurgy, catalysis, activation, transport and
separation phenomena, etc. [1,2]. Unsymmetrical Schiff base ligands with hard and soft
atoms have been widely investigated and readily form stable complexes with most of the
transition metals and the synthesis of these complexes is an important area of study with
implications in bioinorganic chemistry [3-5], catalysis [6] and medical chemistry [7].
Unsymmetrical Schiff base ligands with N, O and S donors have been able to provide diverse
possibilities in structure and chemical properties and these complexes are the most abundant
2

and dominate the field. The presence of both hard and soft donor atoms in one ligand
increases the coordination ability towards hard as well as soft metals [8-13].
Interest in coordination chemistry of tridentate unsymmetrical Schiff base ligands
with NOS donating sites have increased due to capabilities of forming stable complexes of
four, five and six coordinated [14-18] and have a broad range of antifungal [19], antibacterial
[
7, 20], anticancer properties [21]. Tridentate NOS donor unsymmetrical Schiff base ligands
have been able to provide in the 1:1 and/or 1:2 complexes. In all complexes, the Schiff base
ligand behaves as a NOS-tridentate ligand or NS (with soft metal ions) and/or NO-bidentate
(
with hard metal ions) ligand. The most plausible geometry for the 1:2 complexes or the 1:1
complexes appeared to be a square-planar (four coordinated), trigonal bipyramidal (five
coordinated) or a octahedral (six coordinated) [14]. Here, we report the synthesis and
characterization of a new unsymmetrical tridentate NOS Schiff base ligand derived from
salicylaldehyde, 2-aminothiophenol and 1-chloro-2-nitrobenzene and its manganese(II),
nickel(II), copper(II), zinc(II) and cadmium(II) complexes. The structures of copper(II) and
nickel(II) complexes have been determined by X-ray diffraction. This ligand bonded to the
copper(II) center as monobasic and NOS-tridentate ligand in the 1:2 complex and bonded to
the nickel(II) center as monobasic and NO-bidentate ligand in the 1:2 complex. The
spectroscopic data and X-ray diffraction indicated a distorted octahedral structure for the six
coordinate and a distorted square planar structure for the four coordinate complexes.
2
. Experimental
2
.1. Materials and Instrumentation
2
-Aminothiophenol, salicylaldehyde and 1-chloro-2-nitrobenzene were purchased
from Merck and used as received. Other reagents and solvents were of analytical grade and
used without any further purification. Elemental analyses were performed in a CHNS-O-2400
3

II Perkin-Elmer. Infrared spectra were recorded in ATR, using a Bruker FT-IR Equinax-55
-
1
spectrophotometer (4000–400 cm ). MS spectra were obtained using a QP-1100EX
1
13
Shimadzu GC–MS (EI at 70 eV). H and C NMR spectra were recorded witha Bruker AC-
00 NMR spectrometer using CDCl as the solvent and TMS as the internal standard.
3
3
-
3
-3
Conductivity measurements were carried out in 10 mol dm DMF solutions at 25 °C using a
Metrohm 660 conductometer. The electronic spectra were taken in GBC UV-Visible Cintra
1
01 spectrophotometer with 1 cm quartz, in the range 200–1100 nm at 25 °C.
2
.2. X-ray crystal structure determination
The X-ray diffraction data were made on a STOE IPDS-II diffractometer with
2
graphite monochromated Mo Kα radiation (λ = 0.71073 Å). For [CuL ], a dark blue prismatic
crystal with dimensions 0.45 × 0.20 × 0.15 mm and for [NiL ], an orange prismatic crystal
2
with dimensions of 0.50 × 0.40 × 0.15 mm was used for data collection. Cell constants and an
orientation matrix for data collection were obtained by least-squares refinement of the
diffraction data from 3013 unique reflections for [CuL
collected at a temperature of 298(2) K to a maximum 2θ value of 50.00° for [CuL
8.40° for [NiL ] and in a series of ω scans in 1° oscillations and integrated using the Stoe X-
AREA [22] software package. The numerical absorption coefficient, µ, for Mo Kα radiation
2
] and 4601 for [NiL
2
]. Data were
2
] and
5
2
-1
-1
2 2
is 0.816 mm for [CuL ] and 0.472 mm for [NiL ]. A numerical absorption correction was
applied using X-RED [23] and X-SHAPE [24] software. The data were corrected for Lorentz
and polarization effects. The crystal structures were solved by direct methods [25] and
subsequent difference Fourier maps and then refined by full-matrix least-squares procedure
2
on F using anisotropic displacement parameters [25]. All of the hydrogen atoms were
located in a difference Fourier map and then after refined isotropically. Subsequent
refinement then converged with R factors. Atomic factors are from the International Tables
4

for X-ray Crystallography [26]. All refinements were performed using the X-STEP 32
crystallographic software package [27]. Crystal data, experimental details and structure
refinement results are given in Table 1.
Table 1. here
2
2
.3. Synthesis
.3.1. Synthesis of the 2-((nitrophenyl)thio)aniline
2
-Aminothiophenol (5.0 g, 40 mmol), 1-chloro-2-nitrobenzene (6.3 g, 40 mmol) and
potassium carbonate (5.5 g, 40 mmol) were mixed and then fused together at 130-140 °C
with constant stirring for 4 h. The mixture was then cooled, and absolute ethanol (70 mL) was
added. The mixture was stirred for 15 min and then filtered off. The filtrate volume was
reduced to about 10 mL and resulting in the formation of a green precipitate. The precipitate
was decanted off and washed twice with diethyl ether (2 × 10 mL) (Scheme 1). Yield: 7.94 g,
-1
1
8
1%, m.p.: 85 °C. IR (ATR, cm ) 3451, 3360 ν(NH
2
); 1504, 1305 ν(NO ); 734 ν(C-S); H
2
NMR (CDCl , ppm): δH 4.34 (2H, br), 6.62 (1H, t), 6.63 (1H, t), 6.72 (1H, d), 6.73 (1H, d),
3
+
+
7
.19 (4H, m); EI MS (m/z, M ): 248 [M] .
2
.3.2. Synthesis of the 2-((2-(2-nitrophenylthio)phenylimino)methyl)phenol (HL)
A solution of 2-((nitrophenyl)thio)aniline (2.46 g, 10 mmol) in ethanol (40 mL) was
added dropwise to a refluxing solution of salicylaldehyde (1.22 g, 10 mmol) in the same
solvent (20 mL). After refluxing for 8 h the solution was left to evaporate slowly at room
temperature. After 3 days, dark brown crystals of HL were isolated (Scheme 1). Yield: 2.62
-1
g, 75%, m.p.: 137 °C. IR (ATR, cm ) 2500-3200 ν(O-H); 1612 ν(C=N); 1508, 1304 ν(NO );
2
5

1
7
7
8
1
1
40 ν(C-S); H NMR (CDCl
3
, ppm): δH 6.83 (1H, d), 6.88 (1H, t), 7.02 (1H, d), 7.19 (1H, t),
.24 (1H, d), 7.33 (1H, t), 7.42 (1H, t), 7.50 (1H, d), 7.63 (2H, t), 7.70 (1H, d), 8.19 (1H, d),
1
3
3
.88 (1H, s) 12.04 (1H, br); C NMR (CDCl , ppm): δC 117.6, 117.9, 119.5, 119.8, 125.5,
25.6, 126.1, 128.0, 128.7, 132.2, 133.6, 133.7, 135.3, 137.2, 137.4, 145.2, 148.9, 161.7,
+
63.8; UV-Vis in DMF (λ, nm) 277 (logε=5.41), 348 (logε=4.23); EI MS (m/z, M ): 350
+
-1
2
-1
[
HL] ; Λ (DMF) 16.7 Ω cm mol .
m
Scheme 1 here
2
.3.3. General synthesis of the complexes
A solution of MCl
2
(M=Mn, Ni, Cu, Zn, Cd) (1 mmol) in ethanol (30 mL) was added
dropwise to a refluxing solution of 2-((2-(2-nitrophenylthio)phenylimino)methyl)phenol (HL)
0.70 g, 2mmol) in ethanol (50 mL). After refluxing for 2 h, a solution of triethylamin (0.28
(
g, 2mmol) was added and the reaction mixture was refluxed for 1 h. The solution was then
concentrated in a rotary evaporator to ca. 5-10 mL. The complexes were filtered off, washed
with cold ethanol and air-dried (Scheme 2).
Scheme 2. here
[
2
NiL ]
Yield: 696 mg (92%). Anal. Calc. for C38
H
26
N
4
NiO
Found: C, 60.03; H, 3.52; N, 7.21%; IR (ATR, cm ) 1603 ν(C=N); 1506, 1304 ν(NO
ν(C-S); UV-Vis in DMF (λ, nm) 279 (logε=4.35), 350 (logε=4.10), 441 (logε=3.32), 633
6
S
2
: C, 60.25; H, 3.46; N, 7.40%.
-1
2
); 733
+
+
-1
2
-1
(
logε=1.59), 850 (logε=1.27); EI MS (m/z, M ): 756 [NiL
2
] ; Λ (DMF) 27.0 Ω cm mol .
m
6

[
2
CuL ]
Yield: 632 mg (83%). Anal. Calc. for C38
Found: C, 57.99; H, 3.55; N, 7.17%; IR (ATR, cm ) 1607 ν(C=N); 1512, 1305ν(NO
ν(C-S); UV-Vis in DMF (λ, nm) 274 (logε=4.36), 346 (logε=4.08), 630 (logε=1.55); EI MS
H26CuN
4
O
6
S
2
: C, 59.87; H, 3.44; N, 7.35%.
-1
2
); 758
+
+
-1
2
-1
(
m/z, M ): 761 [CuL
2
] ; Λ (DMF) 17.1 Ω cm mol .
m
[
2
ZnL ]
26 4 6 2
Yield: 619 mg (81%). Anal. Calc. for C38H N O S Zn: C, 59.73; H, 3.43; N, 7.33%.
-1
2
Found: C, 59.51; H, 3.47; N, 7.32%; IR (ATR, cm ) 1606 ν(C=N); 1514, 1304ν(NO ); 758
1
ν(C-S); H NMR (CDCl
3
, ppm): δH 6.29 (1H, d), 6.41 (1H, t), 6.74 (1H, d), 6.91 (1H, t), 7.05
1
3
(
1H, d), 7.15 (1H, t), 7.19 (1H, t), 7.33 (3H, m), 7.53 (1H, t), 8.06 (1H, d), 8.20 (1H, s); C
NMR (CDCl , ppm): δC 114.0, 123.1, 123.9, 124.8, 126.1, 126.2, 128.0, 128.6, 129.4, 132.1,
34.4, 134.5, 135.8, 136.6, 136.8, 137.0, 144.9, 145.1 172.4; UV-Vis in DMF (λ, nm) 288
3
1
+
+
-1
2
-1
(
logε=5.36), 348 (logε=5.12); EI MS (m/z, M ): 762 [ZnL
2
] ; Λ (DMF) 7.4 Ω cm mol .
m
[
MnL
2
]·H
Yield: 455 mg (59%). Anal. Calc. for C38
Found: C, 59.40; H, 4.33; N, 7.81%; IR (ATR, cm ) 1614 ν(C=N); 1510, 1305ν(NO
2
O
H
28MnN
4
O
7
S
2
: C, 59.14; H, 3.66; N, 7.26%.
); 757
-1
2
+
ν(C-S); UV-Vis in DMF (λ, nm) 288 (logε=4.73), 359 (logε=4.10); EI MS (m/z, M ): 752
+
-1
2
-1
[
2 m
MnL ] ; Λ (DMF) 25.7 Ω cm mol .
[
CdL
2
2
]·H O
Yield: 473 mg (57%). Anal. Calc. for C38
4 7 2
H28CdN O S : C, 54.91; H, 3.64; N, 6.74%.
-1
Found: C, 54.92; H, 3.64; N, 6.83%; IR (ATR, cm ) 1614 ν(C=N); 1510, 1305 ν(NO
2
); 758
1
ν(C-S); H NMR (CDCl
3
, ppm): δH 6.3-6.9 (4H, m), 7.0-8.0 (8H, m), 8.13 (1H, s); UV-Vis
7

+
+
2 m
in DMF (λ, nm) 272 (logε=4.39), 353 (logε=4.12); EI MS (m/z, M ): 812 [CdL ] ; Λ
-1
2
-1
(
DMF) 16.4 Ω cm mol .
3
. Results and discussion
3
.1. IR spectra
-1
The IR spectrum for 2-((nitrophenyl)thio)aniline shows bands at 3451 and 3360 cm
-1
assignable to the aromatic primary amine vibrations and a band at 734 cm due to the
-
1
2
thioethers stretch. The vibration peaks of NO are observed in 1504 and 1305 cm . The IR
-1
spectrum for the ligand (HL) confirms the presence of imine (1612 cm ) and the absence of
carbonyl and amine functional groups of the starting materials. In this spectrum, a broad band
-
1
in the 2500-3200 cm region is assigned to the ν(O-H) vibration in ligand. The vibration
-
1
peak of C-S in the IR spectrum of ligand (HL) is observed in 740 cm and the vibration
-1
peaks of NO
2
are observed in 1508 and 1304 cm . In the IR spectra of Mn(II), Ni(II), Cu(II),
-
1
Zn(II) and Cd(II)complexes, the bands in the range of 1603–1614 cm are associated with
-1
ν(C=N) vibration. The vibration peaks of NO are observed in the range of 1506-1514 cm
2
-1
and 1304-1305 cm . In the Mn(II), Cu(II), Zn(II) and Cd(II) complexes, the vibration peaks
of C-S are shifted relative to the similar bands of the ligand that show the thioether sulfur
atom coordinated to the metal ions. The vibration peaks of C-S in the Ni(II) complex was not
shifted that shows the thioether sulfur atom uncoordinated to the nickel ion. The absence of
the vibration peak of OH in all complexes exhibit that the OH group is deprotonated and
coordinated [12,18,28-30].
3
.2. NMR spectra
1
13
H NMR and C NMR results, obtained for prepared compounds at ambient
1
temperature in CDCl
3
, are presented in Section 2. The H NMR spectrum of 2-
8

(
(nitrophenyl)thio)aniline shows a significant signal at 4.34 ppm correspond to the NH
2
protons and shows doublet and triplet signals in the 6.62-7.19 ppm regions correspond to the
1
13
aromatic rings protons. The
H
and
C
NMR spectra of the 2-((2-(2-
nitrophenylthio)phenylimino)methyl)phenol (HL) indicate that this compound has
1
synthesized. The H NMR spectra of the ligand (HL), Zn(II) and Cd(II) complexes exhibit a
singlet resonance at 8.88, 8.20 and 8.13 ppm, respectively, which has been assigned to the
HC=N resonance, show the aromatic rings protons in the region 6.29-8.19 ppm and the
1
3
significant signal with 12.04 ppm is assigned to the OH group [18,30]. In the C NMR
spectra of the ligand (HL) and Zn(II) complex, the HC=N carbon resonance is observed in the
1
63.8 and 172.4 ppm, respectively, and the resonances for the aromatic carbons are observed
in the region 114.0-161.7 ppm. Unfortunately, the poor solubility of the Cd(II) complex made
1
3
impossible there’s study by C NMR spectroscopy.
3
.3. Electronic spectra
The electronic spectrum for 0.001 M solutions of the ligand (HL) in DMF shows two
absorption bands at 277 nm (logε=5.41) and 348 nm (logε=4.23), which these bands can be
attributed to π→π* and n→π* transitions [31]. The electronic spectra for 0.001 M solutions
of complexes in DMF show bands at 272 to 288 nm corresponding to π→π* transitions and
show bands at 346 to 359 nm corresponding n→π* and/or charge transfer transitions. In
1
0
5
general, the electronic transitions for Zn(II), Cd(II) (d ) and Mn(II) (d high spin) complexes
are spin-forbidden and hence cannot be observed. Complex Cu(II) shows only one band at
6
30 nm (logε=1.55) corresponds to d→d transition. An intense d→ π* charge transfer band
appears at441 nm in the spectrum of the Ni(II) complex [32]. Moreover, the absorption bands
at 633 nm (logε=1.59) and 850 nm (logε=1.27) are related to the d-d transition.
9

3
.4. Mass spectra
The EI mass spectra of the 2-((nitrophenyl)thio)aniline, the ligand (HL) and the
complexes, provide strong evidence for the formation of these compounds and exhibit peaks
at higher molecular weights. The molecular weights peak in the spectra of 2-
(
(nitrophenyl)thio)aniline, the ligand (HL), the Ni(II), Cu(II), Zn(II), Mn(II) and Cd(II)
complexes, are observed at m/z 248, 350, 756, 761, 762, 752 and 812, respectively.
3
.5. Molar conductivity and elemental analysis
The molar conductance values for ligand (HL) and complexes measured in DMF
-3
-3
-1
2
-1
solution (1×10 mol dm ) fall in the range 7.4-27.0 ohm cm mol . These observed values
of the molar conductance are well within the expected range for non-electrolytes [33]. The
elemental analyses of the complexes indicated the absence of counter ions in the formula.
The elemental analyses for these complexes are in good agreement with the above molecular
formula. In Mn(II), Cu(II), Zn(II) and Cd(II) complexes, it has been observed that the Schiff
base behaves as monobasic and NOS-tridentate ligand in the 1:2 complex. Also, in the
nickel(II) complex, behaves as monobasic and NO-bidentate ligand in the 1:2 complex.
3
.6. X-ray crystallography
Single crystals of Ni(II) complex were obtained by slow evaporation of an ethanol
solution of this compound and Cu(II) complex have been achieved by very slow evaporation
of a dichloromethane solution of this complex. Then, the structures of Ni(II) and Cu(II)
complexes were determined by single crystal X-ray diffraction method. Thermal ellipsoid
plots of [NiL
measurement data are shown in Table1. Selected bond lengths and bond angles are listed in
Table 2.The complex [NiL ] is triclinic and crystallizes in the space group P1 with Z = 1,
2 2
] and [CuL ] are shown in Figs 1 and 2 respectively. The crystallographic and
2
1
0

whereas complex [CuL
2
] is monoclinic and crystallizes in the space group C 2/c with Z = 4.
In the compound [NiL
2
], the nickel(II) atom is four coordinated in a square planar geometry
by two Schiff base anion ligands. Each of the Schiff bases acts as a bidentate ligand through
8
the imine N and the phenolic O atom. As expected for four coordinate d metal complexes,
the structure of [NiL ] adopts a nearly ideal square planar geometry with O(1)-Ni(1)-
2
O(1)#1(Symmetry code: #1 -x+2,-y+1,-z+1) and N(1)-Ni(1)-N(1)#1bond angles of 180.00°
and 180.00(15)°, respectively. The other angles around the nickel(II) are 87.50(8)° and
9
2.50(8)°. The Ni(1)-O(1) and Ni(1)-N(1) bond lengths are 1.837 (2) Å and 1.910(2) Å,
respectively, which are in agreement with the reported values for such distances [34-36].
Each molecule in [NiL ] is involved in intermolecular hydrogen bonding interactions
between the hydrogen of azomethine carbon atoms (H7) of a unit with the NO groups (O2)
2
2
of another unit [H(7)...O(2), 2.494 Å] (Table 3 and Fig. 3). Crystal packing structure of the
complex is stabilized by intermolecular hydrogen bonding interactions (Fig. 3). In the
compound [CuL ], the copper(II) atom is six coordinated in a distorted octahedral geometry
2
by two Schiff base anion ligands. Each of the Schiff base ligands loses one hydrogen atom
and coordinates to the metal ion through the thioether sulfur atom, the imine N and the
phenolic O atom. The coordination environment can be best described as octahedral with a
strongly tetragonal distortion, as often observed in hexa-coordinated Cu(II) complexes. In
this complex the O(1), N(1), O(1)#1 and N(1)#1 (Symmetry code: #1 -x+1/2,-y+1/2,-
z)donors define the equatorial planeand the copper(II) atom lying in this plane (r.m.s.
deviation: 0.0 Å) and the S(1) and S(1)#1 donors occupy the apical positions. The Cu(1)-O
and Cu(1)-N bond lengths are 1.903(2) Å and 1.992(3) Å, respectively (Table 2), which are
in agreement with the reported values for such distances [35,37]. The Cu(1)-S distances are
2
.923(3) Å (Table 2). The longer copper-axial sulfur distances are found in this complex in
comparison with the reported values for such distances [38,39]. The high tetragonal distortion
1
1

can be attributed to the well-known Jahn-Teller theorem, which indicates that for transition
metal compounds in an electronically degenerate state, such as copper(II) complexes,
distortion must occur to lower the symmetry and lower the energy. In the copper(II)
complexes the distortion is usually elongation along the z axis and therefore susceptible to
distortion [40]. The O-Cu-O, N-Cu-N and S-Cu-S bond angles are 180.00° and other angles
around copper(II) are 71.71, 81.17, 98.83, 108.29° (judged angles) and 89.31, 90.61° (bite
angles), which deviate significantly from 90° indicating the distortion from a regular
2
octahedron. Each molecule in [CuL ] is involved in intermolecular hydrogen bonding
interactions between the hydrogen of aromatic carbon atoms (H18) of a unit with the S
thioethers (S1) of another unit [H(18)...S(1), 2.858 Å] (Table 3) and these hydrogen bonds
effective in the stabilization of the crystal structure (Fig. 4).
Fig 1. here
Fig 2. here
Fig. 3. here
Fig. 4. here
Table 2. here
Table 3. here
4
-Conclusion
In this work, we have successfully designed and synthesized the unsymmetrical amine
and then NOS unsymmetrical tridentate Schiff base ligand (HL) containing the NO group
2
and/or hard-soft donors. Then, zinc(II), cadmium(II), manganese(II), copper(II) and nickel(II)
complexes with this ligand were prepared and characterized by analytical and spectroscopic
methods. Molecular structures of [NiL
2
] and [CuL ] were determined by single crystal X-ray
2
1
2

crystallography. Copper(II) and nickel(II) complexes showed distorted octahedral and square
planar geometry about metal center, respectively. Also, this ligand can be bonded to metal
center as NOS-tridentate and NO-bidentate ligand in the 1:2 complex.
Acknowledgements
We are grateful to the Faculty of Chemistry of Yazd University and Ministry of Science,
Research and Technology of Iran, for financial support.
Appendix A. Supplementary data
CCDC 1483017 and 1483019 contain the supplementary crystallographic data for
[
2 2
CuL ] and [NiL ], respectively. These data can be obtained free of charge via
http://www.ccdc.cam.ac.uk/conts/retrieving.html, or from the Cambridge Crystallographic
Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (+44) 1223-336-033; or e-mail:
deposit@ccdc.cam.ac.uk.
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6

2 2
Table 1. Crystallographic and structure refinements data for [CuL ] and [NiL ].
Complex
2
[CuL ]
2
[NiL ]
Empirical formula
Formula weight
Temperature (K)
Wavelength λ (Å)
Crystal system
C
38
H
26CuN
4
O
6
S
2
38 26 4 6 2
C H N NiO S
762.30
298(2)
0.71073
757.44
298(2)
0.71073
Monoclinic
Triclinic
Space group
a (Å)
C 2/c
P1
21.807(4)
10.255(2)
15.906(3)
90
8.1645(16)
10.954(2)
11.206(2)
118.93(3)
96.69(3)
95.52(3)
857.6(4)
1, 1.467
0.742
b (Å)
c (Å)
α (°)
β (°)
106.14(3)
90
γ (°)
3
Volume (Å)
3416.9(12)
4, 1.482
0.816
3
Z, Calculated density (Mg/m )
-
1
Absorption coefficient (mm )
F(000)
1564
390
Crystal size (mm)
0.45 × 0.20 × 0.15
0.50 × 0.40 × 0.15
.11 to 29.20
2
Theta range for data collection (°) 2.21 to 25.00
25<=h<=21
-12<=k<=12
18<=l<=18
-
-11<=h<=11
-15<=k<=14
-15<=l<=15
Limiting indices
-
Reflections collected / unique
Completeness to theta
11528 / 3013 [R(int) = 0.0783]
99.7 %
9664 / 4601 [R(int) = 0.0740]
99.1 %
Absorption correction
Numerical
Numerical
Max. and min. transmission
Refinement method
0.8874 and 0.7103
0.8969 and 0.7081
2
2
Full-matrix least-squares on F
Full-matrix least-squares on F
4601 / 0 / 232
Data / restraints / parameters
3013 / 0 / 232
2
Goodness-of-fit on F
0.927
0.901
Final R indices [I>2sigma(I)]
R1 = 0.0476, wR2 = 0.0860
R1 = 0.0466, wR2 = 0.0851
R indices (all data)
R1 = 0.0909, wR2 = 0.0960
R1 = 0.0940, wR2 = 0.0986
0.422 and -0.248
-
3
Largest diff. peak and hole (eÅ ) 0.358 and -0.184
1
7

Scheme 1. Synthesis of the 2-((nitrophenyl)thio)aniline and the ligand (HL)
Scheme 2. General structure of the complexes.
1
8

2
Fig 1. Molecular structure of [NiL ] showing 50% displacement ellipsoids.
Fig 2. Molecular structure of [CuL ] showing 50% displacement ellipsoids.
2
Fig. 3. Hydrogen bonds interactions in [NiL ].
2
1
9

2
Fig. 4. View of the crystal packing of [CuL ] in the c-direction. Dashed lines indicate
hydrogen bonds
Table 2. Selected bond lengths (Å) and bond angles (°) for [NiL
2
2
] and [CuL ].
2
[NiL ]
2
[CuL ]
Ni(1)-O(1)
1.837 (2)
1.910(2)
1.298(3
Cu(1)-O(1)
Cu(1)-N(1)
Cu(1)-S(1)
Cu(1)-S(1)#1
1.903(2)
1.992(3)
2.923(3)
2.923(3)
180.00(7)
Ni(1)-N(1)
N(1)-C(7)
b
N(1)-C(8)
1.440(3)
180.0
a
a
b
b
O(1)-Ni(1)-O(1)#1
N(1)-Ni(1)-N(1)#1
O(1)-Ni(1)-N(1)
O(1)#1-Ni(1)-N(1)
O(1)-Cu(1)-O(1)#1
N(1)-Cu(1)-N(1)#1
180.00(15)
92.50(8)
87.50(8)
92.50(8)
101.16(11)
114.9(2)
180.00(19)
180.00
b
S(1)-Cu(1)-S(1)#1
a
O(1)-Cu(1)-N(1)
89.38(11)
90.62(11)
89.38(11)
71.71
a
b
O(1)#1-Ni(1)-N(1)#1
C(14)-S(1)-C(13)
C(7)-N(1)-C(8)
O(1)-Cu(1)-N(1)#1
b
O(1)#1-Cu(1)-N(1)#1
S(1)-Cu(1)-N(1)
2
0

C(7)-N(1)-Ni(1)
C(8)-N(1)-Ni(1)
O(2)-N(2)-O(3)
124.45(17)
120.57(15)
122.0(3)
S(1)-Cu(1)-O(1)
S(1)-Cu(1)-N(1)#1
81.17
108.29
98.83
b
b
S(1)-Cu(1)-O(1)#1
Symmetry codes: a) #1 -x+2,-y+1,-z+1 b) #1 -x+1/2,-y+1/2,-z
2 2
Table 3. Hydrogen bonds (Å and deg) for A) [NiL ] and B) [CuL ].
D-H...A
d(D-H)
0.93
d(H...A)
2.494
d(D...A)
3.416
<(DHA)
171.0
A) C(7)-H(7)...O(2)
B) C(18)-H(18)...S(1)
0.93
2.858
3.437
121.5
2
1

Graphical abstract pictogram
Synthesis and characterization of metal complexes with NOS
unsymmetrical tridentate Schiff base ligand. X-ray crystal structures
determination of nickel(II) and copper(II) complexes
Ahmad Ali Dehghani-Firouzabadi, Morteza Sobhani, Behrouz Notash
2
2

Graphical abstract synopsis
Synthesis and characterization of metal complexes with NOS
unsymmetrical tridentate Schiff base ligand. X-ray crystal structures
determination of nickel(II) and copper(II) complexes
Ahmad Ali Dehghani-Firouzabadi, Morteza Sobhani, Behrouz Notash
A unsymmetrical tridentate NOS Schiff base ligand (HL) and its Mn(II), Ni(II), Cu(II), Zn(II)
and Cd(II) complexes have been synthesized and characterized by different physico-chemical
and spectroscopic techniques. The molecular structures of [NiL
2
] and [CuL ] were
2
determined by single crystal X-ray crystallography. Copper(II) and nickel(II) complexes
showed distorted octahedral and square planar geometry about metal center, respectively.
2
3