Metal complexes with thioether containing unsymmetrical N2S donor Schiff base ligand: Crystal and molecular structure of nickel(II) complex

Article abstract of DOI:10.1080/10426507.2019.1709458

A thioether unsymmetrical N₂S donor Schiff base ligand, N-2-((2-nitrophenyl)thio)phenyl)-1-(pyrrole-2-yl)methanimine (HL) and its five complexes [NiL₂], [CuL₂], [ZnHL(H₂O)₂(OAc)₂], [CdHL(H<

Full text of DOI:10.1080/10426507.2019.1709458

Phosphorus, Sulfur, and Silicon and the Related Elements
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Metal complexes with thioether containing
unsymmetrical N2S donor Schiff base ligand:
Crystal and molecular structure of nickel(II)
complex
Ahmad Ali Dehghani-Firouzabadi, Farzaneh Morovati & Behrouz Notash
To cite this article: Ahmad Ali Dehghani-Firouzabadi, Farzaneh Morovati & Behrouz Notash
(2020): Metal complexes with thioether containing unsymmetrical N2S donor Schiff base ligand:
Crystal and molecular structure of nickel(II) complex, Phosphorus, Sulfur, and Silicon and the
Related Elements, DOI: 10.1080/10426507.2019.1709458
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PHOSPHORUS, SULFUR, AND SILICON AND THE RELATED ELEMENTS
https://doi.org/10.1080/10426507.2019.1709458
Metal complexes with thioether containing unsymmetrical N2S donor Schiff base
ligand: Crystal and molecular structure of nickel(II) complex
Ahmad Ali Dehghani-Firouzabadia , Farzaneh Morovatia, and Behrouz Notashb
b
aDepartment of Chemistry, Faculty of Science, Yazd University, Yazd, Iran; Chemistry Department, Shahid Beheshti University,
G. C., Evin, Tehran, Iran
ABSTRACT
ARTICLE HISTORY
Received 13 August 2019
Accepted 23 December 2019
A thioether unsymmetrical N2S donor Schiff base ligand, N-2-((2-nitrophenyl)thio)phenyl)-1-(pyrrole-2-
yl)methanimine (HL) and its five complexes [NiL2], [CuL2], [ZnHL(H2O)2(OAc)2], [CdHL(H2O)2(OAc)2]ꢀ2H2O
and [MnHL(H2O)2(OAc)2]ꢀ2H2O were synthesized. The ligand and metal complexes were characterized
by spectroscopic methods (FT-IR, 1H and 13C NMR, UV–Vis), elemental analyses, mass spectrometry,
and conductance measurements. Of these complexes, [NiL2] was structurally characterized by single-
crystal X-ray crystallography. In this complex, two ligands function as monobasic N2S tridentate and
coordinate through pyrrole-N, thioether-S, and azomethine-N, and the nickel(II) is in distorted octahe-
dral environments.
KEYWORDS
Tridentate ligand; NNS donor;
unsymmetrical ligand;
pyrrole-2-carboxaldehyde;
Schiff base complexes
GRAPHICAL ABSTRACT
CONTACT Ahmad Ali Dehghani-Firouzabadi
aadehghani@yazd.ac.ir
Department of Chemistry, Faculty of Science, Yazd University, 89195-741 Yazd, Iran.
Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/gpss.
Supplemental data for this article is available online at https://doi.org/10.1080/10426507.2019.1709458.
ß 2020 Taylor & Francis Group, LLC

2
A. A. DEHGHANI-FIROUZABADI ET AL.
carboxaldehyde, 2-mercaptoaniline, and 2-nitrochloroben-
zene. Ni(II), Cu(II), Zn(II), Cd(II) and Mn(II) complexes of
this ligand were synthesized and characterized. The com-
plexation reaction of manganese(II), cadmium(II) and
zinc(II) acetate with this N2S ligand gave complexes with a
metal:ligand ratio 1:1, whereas nickel(II) and copper(II)
acetate with this ligand gave a complex with a metal:ligand
ratio 1:2. Of these complexes, [NiL2] was structurally charac-
terized by single-crystal X-ray crystallography. In this com-
plex, two ligands function as monobasic N2S tridentate and
coordinate through pyrrole-N, thioether-S, and azomethine-
N. The single-crystal X-ray structure of [NiL2] shows the
nickel ion to be in a distorted octahedral N4S2 environment.
Introduction
One of the traditional methods of synthesizing ligands and
their complexes is the Schiff base method, and Schiff bases
have been known since 1864 when Hugo Schiff reported the
condensation of primary amines with carbonyl com-
pounds.[1,2] By this method, ligands and complexes can be
synthesized in different classes, such as macrocyclic and
macroacyclic, symmetrical and unsymmetrical, neutral and
ionic, hard and soft and hard-soft donors, flexible and non-
flexible and di- up to multi-dentate.[3–13] The synthesis of
ligands containing a Schiff base and their complexes is very
broad due in part to their potential interest for the chemis-
try, biochemistry, material science and hydrometallurgy,
activation and catalysis.[14,15] Also, syntheses of Schiff base
ligands with specific properties as mentioned above are
important in bioinorganic chemistry, catalysis, and medical
chemistry.[16–18] Interest in thioether tridentate unsymmet-
rical Schiff base ligands with flexibility and hard-soft donat-
ing sites in coordination chemistry has increased. The
reason for this increase is due to their ability to form stable
four-, five-, and six-coordinated complexes and they have
been found to possess a wide range of biological proper-
ties.[19–25] Tridentate ligands L can provide metal complexes
with ML or ML2 stoichiometry. Also, tridentate ligands can
bind to metal centers in complexes through two or three
donor atoms per metal center (bidentate or triden-
Results and discussion
Synthesis
The 2-((nitrophenyl)thio)aniline was obtained according to
Scheme 1 in 92% yield, using triethylamine as a base, by a
modification of a method previously reported for this syn-
thesis.[11,12] The Schiff base ligand, N-2-((2-nitrophenyl)th-
io)phenyl)-1-(pyrrole-2-yl)methanimine (HL) was prepared
from condensation of 2-((nitrophenyl)thio)aniline and
pyrole-2-carbaldehyde. Since the formation of the Schiff
base is a reversible reaction and these are sensitive to mois-
ture and decompose when exposed to air and water, this lig-
tate).[21,22,25] We report here the preparation and character- and (HL) is unstable (sensitive to moisture) and return to
ization of a new unsymmetrical and flexible tridentate N2S the initial material. The syntheses of complexes [NiL2] and
donor Schiff base ligand derived from pyrrole-2- [CuL2] were carried out via [1 þ 2] condensation of HL with
NO2
NO2
NH2
S
Cl
SH
NEt3
O2N
NH
O
NO2
S
S
M(OAc)2
M = Ni, Cu
EtOH
N
M2+
NH
N
N
N
N
NO2
EtOH
S
M(OAc)2
M = Zn, Cd, Mn
OH2
O2N
S
OAc
OAc
M2+
N
OH2
NH
Scheme 1. Synthesis of the ligand (HL) and related complexes.

PHOSPHORUS, SULFUR, AND SILICON AND THE RELATED ELEMENTS
3
Figure 1. Molecular structure of [NiL2] showing 50% displacement ellipsoids.
nickel(II) and/or copper(II) acetate in ethanol. Other com- Mn(II) complexes, the Dꢀ for the acetate (ꢀasym(COO)-
plexes were carried out via [1 þ 1] condensation of HL with ꢀsym(COO)) is more than 200 cmꢁ1, indicating that the acet-
metal(II) acetate in ethanol. The Schiff base ligand and com- ate is a unidentate ligand.[26]
plexes have been characterized by appropriate spectroscopic
methods such as elemental analyses, IR and EI mass spec-
trometry. These complexes are air stable solids and have
elemental analyses consistent with the formulations given in
NMR studies
1
The H NMR and 13C NMR data of the ligand (HL) dis-
the Experimental section.
solved in CDCl3 is shown in the Experimental Section. Due
to the instability of the ligand (HL) and decomposition to
1
the initial material (sensitive to moisture), the H and 13C
FT-IR spectra
1
NMR spectra are accompanied by impurities. The H NMR
spectrum of the ligand (HL) exhibit a singlet resonance at
8.06 ppm, which has been assigned to the imine resonance.
The aromatic rings protons appeared in the region of
6.82–8.25 ppm and the significant signal with 4.52 ppm is
assigned to the NH group. In the 13C NMR spectrum of the
ligand (HL), the HC ¼ N carbon resonance is observed in
the 154.8 ppm and the resonances for the aromatic carbons
are observed in the region 119.3–150.9 ppm.
In the FT-IR spectrum for the ligand (HL), a broad peak at
3374 cmꢁ1, strong peaks at 1610, 729 cmꢁ1 and 1509,
1300 cmꢁ1 are assigned to the N-H, C ¼ N, C-S and NO2
stretching vibration respectively. In the FT-IR spectra of
Ni(II), Cu(II), Zn(II), Cd(II) and Mn(II) complexes, the
bands in the range of 1591–1613 cmꢁ1 are associated with
the imine vibration. Also, the vibration peaks of the nitro
group are observed in the range of 1506–1509 cmꢁ1 and
1299–1303 cmꢁ1. The shifted ꢀC-S of the corresponding
ligands in complexes, found in the ranges 741–755 cmꢁ1
,
Electronic and mass spectra
indicate the thioether S coordinated to the metal ions.[11] In
the IR spectra of Zn(II), Cd(II), and Mn(II) complexes, the
The UV-Vis spectrum for 0.001 M solutions of the ligand
vibration peaks of H2O (3470, 3480, 3440 cmꢁ1, respectively, (HL) in DMF exhibits two absorption bands at 280 nm and
and broad peak at 3000–3500 cmꢁ1 for Cd(II) and Mn(II)), 350 nm, which these bands can be attributed to p!p and
ꢂ
N-H (3369–3373 cmꢁ1
)
and acetate ion (1409–1411, n!p transitions.[27] The UV-Vis spectra for 0.001 M solu-
ꢂ
1647–1649 cmꢁ1) are observed. In the Zn(II) Cd(II) and tions of complexes in DMF exhibit bands at 280 to 285 nm

4
A. A. DEHGHANI-FIROUZABADI ET AL.
Table 1. Crystallographic and structure refinements data for [NiL2].
Table 2. Hydrogen bonds (Å and deg) for [NiL2].
Complex
[NiL2]
D-H … A
d(H … A) (Å)
d(D … A) (Å)
<(DHA) (deg)
Empirical formula
Formula weight
Temperature (K)
Wavelength k (Å)
Crystal system
Space group
a (Å)
C34H24N6NiO4S2
703.40
298(2)
0.71073
Monoclinic
P 21/n
10.753(2)
18.552(4)
16.158(3)
90
99.45(3)
90
C(11)-H(11) … O(3)
C(16)-H(16) … O(1)
C(16)-H(16) … O(2)
2.488
2.668
2.696
3.315
3.557
3.545
148.2
160.1
152.3
in all cases in good agreement with the above molecular for-
mula. These values are indicative of the different coordina-
tive capacity. In Ni(II) and Cu(II) complexes, it showed that
the Schiff base ligand acts as monobasic and NNS-tridentate
in the 1:2 complex. Also, in the Zn(II), Cd(II) and Mn(II)
complexes, it showed that the Schiff base ligand acts as neu-
tral and NS-bidentate in the 1:1 complex.
b (Å)
c (Å)
a (ꢄ)
b (ꢄ)
c (ꢄ)
Volume (Å)3
3179.6(11)
4, 1.469
0.791
1448
Z, Calculated density (Mg/m3)
Absorption coefficient (mmꢁ1
F(000)
)
Crystal size (mm)
0.50 ꢃ 0.25 ꢃ 0.15
2.39 to 25.00
ꢁ11 ꢅ h ꢅ 12
ꢁ22 ꢅ k ꢅ 22
ꢁ19 ꢅ l ꢅ 19
16593/5592 [R(int) ¼ 0.1303]
99.9%
X-ray crystallography
Theta range for data collection (ꢄ)
Limiting indices
Single crystals of nickel(II) complex were prepared by slow
evaporation of a dichloromethane/acetonitrile (1:1) solution
of this complex. Then, the structure of Ni(II) complex was
determined by single crystal X-ray diffraction method. The
thermal ellipsoid plot of [NiL2] is shown in Figure 1. The
details of the X-ray crystal data, and the structure resolution
and refinement, are given in Table 1. Selected bond lengths
and bond angles are shown in supplemental materials Table
S1. The complex [NiL2] is monoclinic and crystallizes in the
space group P 21/n with Z ¼ 4 (supplemental materials Figure
S1). The molecular structure of the complex has a distorted
octahedral geometry around the Ni(II) center, as can be judged
from spread in its observed angles [78.41(13)–104.20(14)ꢄ] and
the trans angles [159.49(16)–174.28(17)ꢄ], by two Schiff base
anion ligands. Each of the Schiff base ligands loses one hydro-
gen atom and coordinates to the metal ion through the imine
N atom, the pyrrole N and the thioether S atom. The bond
lengths found in the structure are within the normal ranges for
Reflections collected/unique
Completeness to theta
Absorption correction
Max. and min. transmission
Refinement method
Numerical
0.8906 and 0.6932
Full-matrix least-squares on F2
5592/0/424
Data/restraints/parameters
Goodness-of-fit on F2
0.974
Final R indices [I > 2sigma(I)]
R indices (all data)
R1 ¼ 0.0639, wR2 ¼ 0.1146
R1 ¼ 0.1345, wR2 ¼ 0.1389
0.345 and ꢁ0.307
Largest diff. peak and hole (eÅꢁ3
)
ꢂ
corresponding to p ! p transitions and show bands at 345
ꢂ
to 375 nm corresponding n ! p and/or charge transfer
transitions. In general, the electronic transitions for Zn(II),
Cd(II) (d10) and Mn(II) (d5 high spin) complexes are spin-
forbidden and hence cannot be observed. Complex Cu(II)
shows only one band at 650 nm and the Ni(II) complex
shows bands at 580 nm and 720 nm corresponds to d ! d this geometry (longest bond length of Ni-S 2.5919(16) Å and
transition.[11,28]
Ni-N 2.061(4) Å). In this complex, the pyrrole N atom of the
Schiff base ligand and the thioether S atom of another Schiff
base ligand are trans coordinated with a bond angle of
159.49(16) and 159.65(16)ꢄ and the imine N atoms of both
Schiff base ligands are trans coordinated with a bond angle of
174.28(17)ꢄ. The Ni(1)-N(3) and Ni(1)-N(6) (the pyrrole N
atom) bond lengths [2.015(5) Å and 2.017(5) Å, respectively]
are shorter than Ni(1)-N(2) and Ni(1)-N(5) (the imine N
atom) bond lengths [2.055(5) Å and 2.061(4) Å, respectively].
Crystal packing structure of the complex is stabilized by inter-
molecular hydrogen-hydrogen, hydrogen-carbon, and hydrogen
bonding interactions. Each molecule in [NiL2] is involved in
intermolecular hydrogen bonding interactions between the
hydrogens of the aromatic carbon atoms (H11 and H16) of
a molecule with the NO2 groups (O1, O2, O3) of another
molecules [H(11) … O(3), 2.488 Å, H(16) … O(1), 2.668 Å,
H(16) … O(2), 2.696 Å] (Table 2 and Figure 2).
The EI mass spectrum of the ligand (HL), provide strong
evidence for the formation of this compound and exhibit
peak at the higher molecular weight. The molecular weights
peak in the spectra of ligand (HL), Ni(II) and Cu(II) com-
plexes are observed at m/z 323, 703 and 707, respectively.
The peaks in the spectra of the Zn(II) and Cd(II) complexes
are observed at m/z 537 and 592 corresponding to
[ZnHL(H2O)2(OAc)2-4H]þ and [CdHL(H2O)2(OAc)2þH]þ,
respectively. The spectra for the Zn(II), Cd(II) and Mn(II) com-
plexes contains peaks due to different fragmentation species,
including 464 [ZnHL(H2O)(OAc)]þ, 423 [ZnHL(H2O)2]þ, 555
[CdHL(OAc)2]þ, 473[CdHL(H2O)2]þ, 496 [MnHL(OAc)2]þ,
437 [MnHL(OAc)]þ, 414 [MnHL(H2O)2]þ.
Conductance measurements and elemental analysis
Molar conductivity data for ligand (HL) and complexes
measured at room temperature using DMF as solvent Experimental
(1 ꢃ 10ꢁ3 mol dmꢁ3) fall in the range 2.7–28.1 Xꢁ1 cm2
Materials and physical measurements
molꢁ1. These obtained values of the molar conductance are
well within the expected range for non-electrolytes.[29] Also,
All the starting materials and solvents for syntheses were
the elemental analysis data for these complexes were accord used as received from Merck or Aldrich Chemical Co. Inc.

PHOSPHORUS, SULFUR, AND SILICON AND THE RELATED ELEMENTS
5
Figure 2. View of the crystal packing of [NiL2] in the c-direction. Dashed lines indicate hydrogen bonds.
Carbon, Hydrogen, Nitrogen microanalyses were performed Synthesis
in a CHNS-O-2400 II Perkin-Elmer. UV–Vis spectra were
Synthesis of the N-2-((2-nitrophenyl)thio)phenyl)-1-(pyrrole-2-
yl)methanimine (HL)
measured on a GBC UV-Visible Cintra 101 spectrophotometer
and FT-IR spectra were recorded in ATR, with Bruker FT-IR
Equinax-55 spectrophotometer (4000–400 cmꢁ1). Mass spectra
were obtained using a QP-1100EX Shimadzu GC–MS (EI at
The 2-((nitrophenyl)thio)aniline was prepared by a modifica-
tion procedure of our other works.[11,12] The dissolved
2-((nitrophenyl)thio)aniline (1.23 g, 5 mmol) in absolute etha-
nol (20 mL) was added to a refluxing solution of pyrrole-2-car-
boxaldehyde (0.48 g, 5 mmol) in the same solvent (5 mL). After
refluxing for 8 h, the solution was vacuum evaporated to yield
the crude product as a brown oil. The product was rubbed
with diethyl ether and n-hexane. The product (HL) was sepa-
rated in brown oil (Scheme 1). Yield: 1.24 g, 77%; UV-Vis in
DMF (k, nm) 280, 350; IR (ATR, cmꢁ1) 3374 ꢀ(N-H); 1610
1
70 eV). The H and 13C NMR spectra were recorded in CDCl3
on a Bruker AC-400 NMR spectrometer using TMS as an
internal standard. Conductance measurements of ca. 10ꢁ3 mol
dmꢁ3 solutions in DMF at 25 ꢄC were measured by means of
a Metrohm 660 conductometer
X-ray crystal structure determination
1
ꢀ(C ¼ N); 1509, 1300 ꢀ(NO2); 729 ꢀ(C-S); H NMR (CDCl3,
Red crystals of [NiL2] were obtained by slow evaporation
from dichloromethane/acetonitrile (1:1) solution of this
complex. The X-ray diffraction data were recorded on an
STOE IPDS-II diffractometer with graphite monochromated
Mo Ka radiation (k ¼ 0.71073 Å). A red block shape crystal
with dimensions 0.50 ꢃ 0.25 ꢃ 0.15 mm was applied for data
collection. Cell parameters and an orientation matrix for
data collection were refined by the least-squares refinement
of the diffraction data from 5592 unique reflections. Data
were collected at a temperature of 298(2) K to a maximum
2h value of 50.00ꢄ and in a series of x scans in 1ꢄ oscillation
and integrated using the Stoe X-AREA software package.[30]
The numerical absorption coefficient, m, for Mo Ka radi-
ation is 0.791 mmꢁ1. Numerical absorption correction was
applied using X-RED and X-SHAPE software.[31,32] All data
were corrected for Lorentz and polarization effects. The
crystal structure was solved by direct methods and subse-
quent difference Fourier maps and then refined by full-
matrix least-squares procedure on F2 values for all unique
data.[33] All non-hydrogen atoms were refined with anisotropic
thermal parameters whereas H-atoms were included at esti-
mated positions. Subsequent refinement then converged with R
factors. Atomic factors are from the International Tables for
X-ray Crystallography.[34] All refinements were performed
using the X-STEP 32 crystallographic software package.[35] The
details of data collection, refinement and crystallographic data
are summarized in Table 1.
ppm): dH 4.52 (1H s) 6.82 (1H, d), 6.91 (1H, t), 7.11 (1H, t),
7.15 (1H, d), 7.22 (1H, t), 7.28 (1H, t), 7.34 (1H, d), 7.45 (1H,
d), 7.53 (1H, t), 7.61 (1H, d), 8.06 (1H, s), 8.25 (1H, d); 13C
NMR (CDCl3, ppm): dC 119.3, 124.1, 125.2, 125.5, 126.2,
127.3, 129.1, 131.8, 132.5, 133.3, 133.9, 136.6, 137.9, 145.1,
149.7, 150.9, 154.8; Anal. Calc. for C17H13N3O2S: C, 63.14; H,
4.05; N, 12.99%. Found: C, 62.76; H, 4.13; N, 12.75%; EI MS
(m/z, Mþ): 323 [HL]þ; Km (DMF) 2.9 Xꢁ1 cm2 molꢁ1
.
General synthesis of the complexes
The dissolved 2-((nitrophenyl)thio)aniline (0.49 g, 2 mmol) in
absolute ethanol (10 mL) was added to a refluxing solution of
pyrrole-2-carboxaldehyde (0.19 g, 2 mmol) in the same solvent
(5 mL). After refluxing for 8 h, a solution of M(OAc)2 (M ¼ Ni,
Cu, Zn, Cd, Mn) (1 mmol) in ethanol (20 mL) was added drop-
wise to a refluxing solution, and the reaction mixture was
refluxed for 1 h. For the Ni(II) and Cu(II) complexes, the solu-
tion was then concentrated in a rotary evaporator to ca.
5–10 mL, the solid product filtered off and crystallized in the
CH3CN/CH2Cl2 (1:1). For other complexes, the solution was vac-
uum evaporated to yield the crude product. Petroleum benzene
(2ꢃ 10 mL) was added to the residue remaining in the flask and
rubbed. Then, the liquid was decanted, and the residue solution
was evaporated until a powder remained (Scheme 1).
[NiL2]. UV-Vis in DMF (k, nm) 285, 350, 580, 720; IR
(ATR, cmꢁ1) 1591 ꢀ(C ¼ N); 1506, 1303ꢀ(NO2); 750 ꢀ(C-S);

6
A. A. DEHGHANI-FIROUZABADI ET AL.
EI MS (m/z, Mþ): 703 [NiL2]þ; Anal. Calc. for
C34H24N6NiO4S2: C, 58.00; H, 3.72; N, 11.83%. Found: C,
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[CuL2]. UV-Vis in DMF (k, nm) 280, 345, 650; IR (ATR,
cmꢁ1) 1613 ꢀ(C ¼ N); 1509, 1302 ꢀ(NO2); 747 ꢀ(C-S); EI
MS (m/z, Mþ): 707 [CuL2]þ; Anal. Calc. for
C34H24CuN6O4S2: C, 57.64; H, 3.49; N, 11.80%. Found: C,
57.66; H, 3.42; N, 11.87%; Km (DMF) 4.3 Xꢁ1 cm2 molꢁ1
.
[ZnHL(H2O)2(OAc)2]. UV-Vis in DMF (k, nm) 280, 345; IR
(ATR, cmꢁ1) 3470 ꢀ(H2O); 3372 ꢀ(N-H); 1409, 1648
ꢀ(OAc); 1610 ꢀ(C ¼ N); 1509, 1299 ꢀ(NO2); 741 ꢀ(C-S); EI
MS (m/z, Mþ): 537 [ZnHL(H2O)2(OAc)2-4H]þ, 464
[ZnHL(H2O)(OAc)]þ, 423 [ZnHL(H2O)2]þ; Anal. Calc. for
C21H23N3O8SZn: C, 45.59; H, 4.18; N, 7.25%. Found: C,
46.46; H, 4.27; N, 7.74%; Km (DMF) 2.7 Xꢁ1 cm2 molꢁ1
.
[CdHL(H2O)2(OAc)2]ꢀ2H2O. UV-Vis in DMF (k, nm) 280,
370; IR (ATR, cmꢁ1) 3480, 3000–3500 ꢀ(H2O); 3369 ꢀ(N-H);
1409, 1647 ꢀ(OAc); 1611 ꢀ(C ¼ N); 1508, 1302 ꢀ(NO2); 755
ꢀ(C-S); EI MS (m/z, Mþ): 592[CdHL(H2O)2(OAc)2þH]þ,
555 [CdHL(OAc)2]þ, 473[CdHL(H2O)2]þ; Anal. Calc. for
C21H27CdN3O10S: C, 40.04; H, 3.83; N, 5.70%. Found: C,
40.30; H, 4.35; N, 6.71%; Km (DMF) 3.2 Xꢁ1 cm2 molꢁ1
.
[MnHL(H2O)2(OAc)2]ꢀ2H2O. UV-Vis in DMF (k, nm) 280,
375; IR (ATR, cmꢁ1) 3440, 3000–3500 ꢀ(H2O); 3373 ꢀ(N-
H); 1411, 1649 ꢀ(OAc); 1610 ꢀ(C ¼ N); 1508, 1300 ꢀ(NO2);
744 ꢀ(C-S); EI MS (m/z, Mþ): 496 [MnHL(OAc)2]þ, 437
[MnHL(OAc)]þ, 414 [MnHL(H2O)2]þ; Anal. Calc. for
C21H27MnN3O10S: C, 42.51; H, 7.32; N, 4.41%. Found: C,
42.94; H, 7.15; N, 3.95%; Km (DMF) 28.1 Xꢁ1 cm2 molꢁ1
.
Conclusion
In this paper, we have successfully designed and synthesized
the N2S unsymmetrical tridentate Schiff base ligand (HL) con-
taining NO2 group and hard-soft donors. This ligand can form
neutral and anionic complexes and can be bonded to metal
centers in complexes through two or three donor atoms per
metal center (bidentate or tridentate). Also, nickel(II),
copper(II), zinc(II), cadmium(II) and manganese(II) complexes
with this ligand were prepared and characterized by appropri-
ate spectroscopic methods. Molecular structure of [NiL2] was
determined by single crystal X-ray crystallography and showed
distorted octahedral geometry about metal center.
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and Characterization of Metal Complexes with NOS
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Funding
We are grateful to the Faculty of Chemistry of Yazd University and the
Ministry of Science, Research and Technology of Iran, for finan-
cial support.
ORCID
Ahmad Ali Dehghani-Firouzabadi
http://orcid.org/0000-0003-1658-4322

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