Diorganotin(IV) complexes of 3,5-dichloro-2-hydroxybenzaldehyde-N(4)-ethylthiosemicarbazone: Synthesis, spectral characterization and crystal structure

Article abstract of DOI:10.1016/j.ica.2015.06.015

Three new diorganotin(IV) complexes of the formulae [Me₂Sn(cdet)] (2), [Bu₂Sn(cdet)] (3) and [Ph₂Sn(cdet)] (4) have been synthesized by the reaction of 3,5-dichloro-2-hydroxybenzaldehyde-N(4)-ethylthiosemicarbazone [H

Full text of DOI:10.1016/j.ica.2015.06.015

Inorganica Chimica Acta 435 (2015) 103–108
Contents lists available at ScienceDirect
Inorganica Chimica Acta
journal homepage: www.elsevier.com/locate/ica
Diorganotin(IV) complexes of 3,5-dichloro-2-hydroxybenzaldehyde-
N(4)-ethylthiosemicarbazone: Synthesis, spectral characterization
and crystal structure
⇑
M.A. Salam, Rosenani A. Haque
The School of Chemical Sciences, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia
a r t i c l e i n f o
a b s t r a c t
Article history:
Three new diorganotin(IV) complexes of the formulae [Me Sn(cdet)] (2), [Bu Sn(cdet)] (3) and
2
2
Received 24 March 2015
Received in revised form 19 June 2015
Accepted 23 June 2015
[
Ph
ethylthiosemicarbazone [H
in absolute methanol. These compounds have been characterized by CHN analyses, UV–Vis, FT-IR, H,
2
Sn(cdet)] (4) have been synthesized by the reaction of 3,5-dichloro-2-hydroxybenzaldehyde-N(4)-
2
cdet, (1)] and appropriate diorganotin(IV) chloride in the presence of KOH
1
Available online 29 June 2015
1
3
119
C and
diphenyltin(IV) complex (4) have been determined by X-ray diffraction analysis. The ligand H
remains as the thione form in the solid state. The crystal structure of [Ph Sn(cdet)] (4) revealed that
the ligand is coordinated to central tin(IV) atom as a dinegatively tridentate chelating agent via the phe-
Sn NMR spectroscopic techniques. The molecular structures of the ligand (1) and its
2
cdet (1)
Keywords:
2
3
,5-Dichloro-2-hydroxybenzaldehyde-N(4)-
ethylthiosemicarbazone
Synthesis
1
19
noxide oxygen atom, the azomethine nitrogen atom and the thiolate sulfur atom. The
Sn NMR chem-
ical shift for the complexes (2–4) are found to be À177.08 to À169.22 ppm, confirming five coordinated
tin(IV) centre. X-ray crystal structure showed that the coordination geometry of central tin(IV) atom is
distorted trigonal bipyramid. The oxygen and sulfur atoms are in axial positions while two phenyl groups
and the azomethine nitrogen atom of the ligand occupy the equatorial positions.
Ó 2015 Elsevier B.V. All rights reserved.
Organotin(IV) complexes
Spectral characterization
Crystal structure
1
. Introduction
Organotin(IV) compounds have been extensively studied for
complexes have been attracting the attention of researchers due
to their considerable structural diversity. A series of diorganotin
complexes were synthesized and investigated for their structural
chemistry and various applications as PVC stabilizers, metal-based
drugs and biocides [30–33]. Earlier reports, notably those of Sousa
et al., and Tahereh et al., have reported the organotin(IV)
complexes of substituted-N(4)-phenylthiosemicarbazones with
potential biological properties [34,35]. Currently, the synthesis of
organotin(IV) derivatives with thiosemicarbazones having two
or more donor atoms has become a popular research area.
Organotin(IV) complexes of ONS-tridentate N4-heterocyclic
thiosemicarbazones were reported by Sousa et al., with the
tin(IV) atoms exhibiting distorted trigonal bipyramidal (TBP)
geometry [36]. To our best knowledge, there are still very little
information available regarding the synthesis and structural stud-
ies of diorganotin(IV) complexes containing ONS-tridentate
thiosemicarbazone ligand. Motivated by these promising studies,
we find it desirable to investigate the synthesis and coordination
mode of diorganotin(IV) complexes with 3,5-dichloro-2-hydroxy-
benzaldehyde-N(4)-ethylthiosemicarbazone. This study also
reported different spectroscopic characterizations of the
diorganotin(IV) complexes and X-ray crystal structure of one rep-
resentative complex.
their industrial, agricultural and medical applications [1–4].
Thiosemicarbazones have received much attention recently due
to the extensive application in the chemotherapeutic field [5,6].
Thiosemicarbazones and their metal complexes are important ser-
ies of compounds due to their potential biological activity as anti-
fungals, anti-virals, anti-malarials and anti-tumour agents [7–14].
In particular, transition metal complexes with substituted
thiosemicarbazones have received much attention due to their
coordination chemistry and potential biological activity [15–22].
The N(4)-substituted thiosemicarbazones and their metal com-
plexes exhibit significant biological activities which vary from
those of either metal atom or parent ligands [23–27]. Recently,
Mouayed et al., have reported coordination chemistry of thiosemi-
carbazonato molybdenum (VI) complexes and their biological
activity against various tumour cell lines [28,29]. Organotin
⇑
Corresponding author. Tel.: +60 46533578, +60 1136212090.
E-mail addresses: salambpx@yahoo.com (M.A. Salam), rosenani@usm.my
(
R.A. Haque).
http://dx.doi.org/10.1016/j.ica.2015.06.015
020-1693/Ó 2015 Elsevier B.V. All rights reserved.
0

1
04
M.A. Salam, R.A. Haque / Inorganica Chimica Acta 435 (2015) 103–108
2
. Experimental
2
2.3. Synthesis of [Me Sn(cdet)] (2)
2.1. Materials and methods
H
2
cdet (1) (0.292 g, 1.0 mmol) was dissolved in absolute metha-
nol (10 mL) in a round-bottom reaction flask under nitrogen atmo-
sphere. KOH (0.11 g, 2.0 mmol) dissolved in methanol was added
dropwise to the ligand solution and the colour changed to orange.
The resulting mixture was refluxed under nitrogen for 1 h. Then, a
methanolic solution of dimethyltin(IV) dichloride (0.219 g,
1.0 mmol) was added dropwise and resulted in a yellow solution.
The resulting reaction mixture was refluxed for 5 h (Scheme 2)
and cooled to room temperature. Potassium chloride (KCl) was fil-
tered off and the solution dried in desiccators over anhydrous silica
gel. Yield: 0.39 g, 76%: M.p: 268–270 °C: Molar conductivity
All reagents were purchased from Fluka, Aldrich and Sigma. All
solvents were received as reagent grade and used without further
purification. Melting point was measured on a Stuart Scientific
SMP1 melting point apparatus. UV–Vis spectra were recorded in
DMSO solution with a Perkin Elmer Lambda 25 UV–Vis spec-
trophotometer. Infrared (IR) spectra were measured on a Perkin
Elmer System 2000 spectrophotometer using the KBr disc method
in the range 4000–400 cm at room temperature. 1H, C and
À1
13
1
19
Sn NMR spectra were recorded on a Bruker 500 and 400 MHz
NMR spectrophotometer relative to SiMe and SnMe in DMSO sol-
À3
À1
À1
2
À1
(1 Â 10 mol L ; DMSO)
X
cm mol : 11.30: UV–Vis (DMSO)
4
4
À1
vent. Elemental analysis was conducted using a Perkin Elmer 2400
Series-11 CHN analyzer. Molar conductivity measurements were
carried out with a Jenway 4510 conductivity meter using DMSO
as a solvent. X-ray crystallographic data were recorded on a
Bruker SMART APEXII CCD area-detector diffractometer using gra-
k
max/nm: 270, 341, 380, 458: FT-IR (KBr, cm
) mmax: 3180 (s, NH),
1592 (m, C@N), 1526 (s, Caro–O), 1023 (m, N–N), 1315, 822 (w,
1
C–S), 608 (w, Sn–C), 557 (w, Sn–O), 482 (w, Sn–N). H NMR
2
(DMSO-d
6
, ppm, J[119Sn,1H]): 8.85 (s, 1H, CS–NH), 8.20 (s, 1H,
CH@N), 8.10 (s, 1H, PhC4–H), 7.70 (s, 1H, PhC6–H), 3.67 (m, 2H,
CH ), 1.10 (t, 3H, CH ) 1.04 (s, 6H, Sn–(CH
[86.31 Hz]). 13
NMR (DMSO-d ppm, J[( C– Sn]): 170.13 (C@S), 168.24
(C@N), 144.88–130.55 (Ph–C), 30.82 (CH ), 18.52 (CH ), 14.85
Sn NMR (DMSO-d
, ppm): À169.22.
OSSn: C, 32.84; H, 3.44; N, 9.57%.
phite monochromated Mo K
a
radiation (k = 0.71073 Å) at 100 K.
2
3
)
3 2
C
1
13
119
The data were collected and reduced using APEX2 and SAINT pro-
grams. The structure of compounds was solved by direct methods
6
,
2
3
2
119
and was refined using the full-matrix least-squares method on F
3
(Sn–CH ), [562.33 Hz].
6
using the SHELXTL program [37]. All nonhydrogen atoms were
anisotropically refined. The molecular graphics were created using
Anal. Calc. for C12H15Cl N
2 3
Found: C, 32.93; H, 3.55; N, 9.68%.
The other diorganotin(IV) complexes (3–4) were synthesised
following the same procedure by using the appropriate
diorganotin(IV) chloride(s) (Scheme 2).
SHELXTL-97.
2.2. Synthesis of 3,5-dichloro-2-hydroxybenzaldehyde-N(4)-
ethylthiosemicarbazone [H cdet, (1)]
2
A
solution of 3,5-dichloro-2-hydroxybenzaldehyde (0.76 g,
4
4
.0 mmol) in methanol (20 mL) was added to a solution of
-ethyl-3-thiosemicarbazide (0.48 g, 4.0 mmol) in methanol
6
H
N
Cl
H
N
CH -CH3
2 2
R SnCl
5
4
1
2
2
+
N
(
20 mL). The resulting yellow solution was refluxed with stirring
3
OH
S
for 2 h (Scheme 1) and then filtered, washed with cold methanol
and dried in desiccators over anhydrous silica gel. Yield: 0.98 g,
Abs. MeOH KOH
Refluxed, 5 h N2 atmosphere
Cl
7
9%: M.p: 185–187 °C: UV–Vis (DMSO) kmax/nm: 267, 338, 376:
À1
FT-IR (KBr, cm
) mmax: 3405 (s, OH), 3268, 3186 (s, NH), 1635
1
(
m, C@N), 1549 (s, Caro–O), 989 (m, N–N), 1367, 857 (w, C–S).
H
Cl
6
H
N
CH -CH
2 3
N
5
4
1
N
NMR (DMSO-d
6
, ppm): 11.40 (s, 1H, OH), 10.47 (s, 1H, N–NH),
8
.83 (s, 1H, CS–NH), 8.28 (s, 1H, CH@N), 8.05 (s, 1H, PhC4–H),
2
1
3
3
S
O
7
.73 (s, 1H, PhC6–H), 3.61 (m, 2H, CH
, ppm): 186.60 (C@S), 150.52 (C@N), 137.58–
22.57 (Ph–C), 30.61 (CH ), 18.46 (CH ). Anal. Calc. for
OS: C, 41.06; H, 3.76; N, 14.37. Found: C, 40.98; H,
.56; N, 14.09%.
2
), 1.13 (t, 3H, CH
3
).
C
Sn
Cl
NMR (DMSO-d
6
R
R
1
C
3
2
3
Where, R = Me (2), R = n-Bu (3), R = Ph (4)
10 2 3
H11Cl N
Scheme 2. Reaction scheme for the synthesis of diorganotin(IV) complexes (2–4).
H
S
Cl
H2N
+
N
CH -CH
2
O
N
3
H
H
OH
4-ethyl-3-thiosemicarbazide
Cl
-
H O
2
3
,5-dichloro-2-hydroxybenzaldehyde
H
H
Cl
Cl
H
N
N
N
CH -CH
N
CH -CH
2
2
3
3
N
N
OH
Thione form
Scheme 1. Synthesis of 3,5-dichloro-2-hydroxybenzaldehyde-N(4)-ethylthiosemicarbazone [H
S
OH
SH
Cl
Cl
Thiol form
2
cdet, (1)].

M.A. Salam, R.A. Haque / Inorganica Chimica Acta 435 (2015) 103–108
105
2
.4. Synthesis of [Bu
2
Sn(cdet)] (3)
These bands are shifted a little upon complexation due to intra
ligand transition. An additional absorption band in the 458–
437 nm range for complexes (2–4) can be assigned to the ligand
to metal charge transfer (LMCT) transitions [39]. This band indi-
cates that coordination takes place between the ligand and
Sn(IV) atom.
Yield: 0.47 g, 78%: M.p: 254–256 °C: Molar conductivity
À3
À1
À1
2
À1
(
k
1 Â 10 mol L ; DMSO)
X
cm mol : 13.23: UV–Vis (DMSO)
À1
max/nm: 269, 340, 379, 448: FT-IR (KBr, cm
) mmax: 3193 (s, NH),
1
587 (m, C@N), 1518 (s, Caro–O), 1019 (m, N–N), 1318, 821 (w,
1
C–S), 612 (w, Sn–C), 555 (w, Sn–O), 473 (w, Sn–N). H NMR
DMSO-d , ppm): 8.88 (s, 1H, CS-NH), 8.25 (s, 1H, CH@N), 8.12 (s,
H, PhC4–H), 7.62 (s, 1H, PhC6–H), 3.64 (m, 2H, CH ), 1.14 (t, 3H,
CH ), 1.43–1.35 (m, 2H Sn–CH –CH –CH –CH ), 1.28–1.20 (m,
H, Sn–CH –CH –CH –CH ), 1.16–1.11 (m, 2H, Sn–CH –CH
CH –CH ), 1.06–0.91 (t, 3H, Sn–CH
DMSO-d
(
1
6
3.3. Infrared spectra
2
The strong bands of
m
(OH) and
m
(N–NH) groups at 3405 and
3
2
2
2
3
À1
3
268 cm of the free ligand (1) disappeared in the complexes
2
2
2
2
3
2
2
–
(2–4) suggesting coordination via the phenolic oxygen and thiolate
1
3
2
3
2
–CH
, ppm, J( C– Sn]): 169.41 (C@S), 162.11 (C@N),
48.31–132.25 (Ph–C), 30.60 (CH ), 18.38 (CH ), 31.23, 28.31,
Sn NMR (DMSO-d , ppm):
OSSn: C, 41.33; H, 5.20; N,
.03. Found: C, 41.26; H, 5.12; N, 8.12%.
2
–CH
2
–CH
3
).
C NMR
sulfur to the tin(IV) ion, respectively. The ligand (1) showed
1
13
119
(
6
À1
m(C@N) stretching vibration at 1635 cm which is shifted to lower
1
2
2
1
3
frequencies in the spectra of the complexes (2–4) indicating coor-
dination via azomethine nitrogen to tin(IV) ion [40]. The medium
19
4.26, 20.75 (Sn–Bu) [548.45 Hz].
6
À171.52. Anal. Calc. for C18
H27Cl
2
N
3
À1
m(Caro–O) band at 1549 cm for free ligand (1) is shifted to lower
8
frequencies in the spectra of the complexes suggesting coordina-
tion via phenolic oxygen atom to tin(IV) ion. The frequency of
2.5. Synthesis of [Ph
2
Sn(cdet)] (4)
m(N–N) band was found to shift to higher frequencies in the com-
plexes compared to the free ligand further confirming the coordi-
Yield: 0.48 g, 75%: M.p: 243–245 °C: Molar conductivity
nation via the azomethine nitrogen [41]. The free ligand (1)
À3
À1
À1
2
À1
(
k
1
1 Â 10 mol L ; DMSO)
X
cm mol : 9.58: UV–Vis (DMSO)
À1
displayed two bands at 1367 and 857 cm due to stretching and
À1
max/nm: 272, 342, 381, 437: FT-IR (KBr, cm
) mmax: 3198 (s, NH),
bending vibration of
at 1331–1315 and 822–814 cm range in the complexes (2–4),
indicating the coordination via thiolate sulfur atom [42].
m
(C@S), which is shifted to lower frequencies
581 (m, C@N), 1520 (s, Caro–O), 1027 (m, N–N), 1331, 814 (w,
À1
1
C–S), 609 (w, Sn–C), 564 (w, Sn–O), 449 (w, Sn–N). H NMR
DMSO-d , ppm): 8.84 (s, 1H, CS–NH), 8.19 (s, 1H, CH@N), 8.14–
.64 (m, 12H, Ph–H), 3.65 (m, 2H, CH
(
7
6
Moreover, the two new band ranges at 564–555 and 482–
1
3
2
), 1.16 (t, 3H, CH
ppm, J( C– Sn]): 168.74 (C@S), 164.53
C@N), 149.05–129.61 (Ph–C), 30.75 (CH ), 18.48 (CH
, ppm): À177.08. Anal. Calc. for
OSSn: C, 46.93; H, 3.40; N, 7.46. Found: C, 46.98; H,
3
).
C
À1
4
49 cm
provide a strong confirmation for the existence of
(Sn–N), respectively, in the complexes [43].
According to the above spectral results, it is established that
cdet (1) is tridentate coordinating to the Sn(IV) centre via the
1
13
119
6
NMR (DMSO-d ,
m(Sn–O) and m
(
[
C
2
3
)
1
19
552.34 Hz].
Sn NMR (DMSO-d
6
H
2
22 2 3
H19Cl N
phenolic oxygen, the azomethine nitrogen and thiolate sulfur
atoms.
3
.47; N, 7.54%.
1
13
119
3
. Results and discussion
3.4. H, C and
Sn NMR spectra
3
.1. Synthesis
The NMR spectral studies of the compounds 1–4 were accom-
plished and interpreted based on the atom labeling in Scheme 2.
The sharp singlet that appeared for the OH proton of the free ligand
at 11.40 ppm disappears in the complexes, indicating deprotona-
tion of oxygen atom and coordination of the phenolic oxygen to
the Sn(IV) atom. The singlet attributed to the N-NH proton at
10.47 ppm for the free ligand (1) is absent in the complexes (2–
4), providing evidence for coordination of the thiolate sulfur to
the Sn(IV) atom. The resonance signal due to the CH@N
(8.28 ppm) in the free ligand is slightly shifted to a downfield
region at 8.25–8.19 ppm in the complexes suggesting deshielding
after coordination to Sn(IV) atom. The aromatic protons of the
ligand and its complexes were observed in the region of 8.12–
The 3,5-dichloro-2-hydroxybenzaldehyde-N(4)-ethylthiosemi-
carbazone (H
3
2
cdet) was prepared by the condensation reaction of
,5-dichloro-2-hydroxybenzaldehyde and 4-ethyl-3-thiosemicar-
bazide. This ligand may exist in two tautomeric forms, either thiol
or thione tautomer (Scheme 1). Three new diorganotin(IV) com-
plexes (2–4) were prepared by the direct reaction of H cdet (1)
2
with appropriate diorganotin(IV) chloride(s) under nitrogen atmo-
sphere in the presence of KOH in 1:2:1 M ratio (Scheme 2). All the
diorganotin(IV) complexes are yellow solids, air stable and
soluble in CHCl
3 2 2
, CH Cl , DMSO, DMF and THF at room tempera-
ture. The molar conductivities of the complexes were 13.23–
9
À1
2
À1
.58
X
cm mol in DMSO, which indicates the neutral beha-
7.62 ppm. For complex 2, the resonance signal of the two methyl
2
viour of the diorganotin(IV) complexes [38]. All the complexes
have been characterized by various spectroscopic techniques and
analytical methods. The analytical data and physical properties of
the compounds 1–4 are presented in the Section 2. The molecular
structures of the H
been confirmed with the help of X-ray diffraction studies.
Investigations exhibited that H cdet (1) coordinate in ONS-triden-
tate as dinegative deprotonated in all complexes.
groups attached to tin(IV) centre appears at 1.02 ppm with
[
J
1
19
1
Sn, H] of 86.31 Hz confirming five coordinated tin(IV) atom
and similar to those previously reported [44,45]. The signals
observed in the region at 3.67–3.61 and 1.16–1.10 ppm have been
assigned to the (–CH ) and (–CH ) protons of the ligand and its
2
cdet (1) and its diphenyltin(IV) complex 4 have
2
3
complexes, respectively. The butyl groups bonded to the Sn(IV)
centre appear as a multiplet at 1.43–1.11 ppm and as a triplet at
1.06–0.91 ppm.
2
The 13C NMR spectra of all complexes showed significant infor-
mation to support the proposed structures. The signal of the (C@S)
group for ligand (1) appeared at 186.60 ppm which is shifted to an
upfield region at 170.13–168.74 ppm in the complexes (2–4),
authenticated coordination of (C–S) group to Sn(IV) atom. For all
complexes, the downfield chemical shifts of (C@N) carbon were
found in comparison with the free ligand, indicating bonding of
azomethine nitrogen to Sn(IV) atom. The chemical shifts for the
3
.2. UV–Vis spectra
2
The electronic spectra of the H cdet (1) and its complexes (2–4)
were measured in DMSO at room temperature. Three absorption
bands were observed at 262, 328 and 361 nm in the UV–Vis spectra
of ligand (1), which are assigned to
ring and n–
⁄
p–p
transition of the aromatic
⁄
p
transitions of the azomethine and thiolate function.

1
06
M.A. Salam, R.A. Haque / Inorganica Chimica Acta 435 (2015) 103–108
aromatic carbons were found to be slightly more downfield for the
complexes than the free ligand. The chemical shift values for the (–
2 3
CH CH ) carbons was found at 30.82–30.60 and 18.52–18.38 ppm
1
13
119
region, respectively. The coupling constant J( C– Sn) values
indicate the possible coordination arrangement of diorganotin(IV)
1
13
119
compounds in solution. The coupling constant J( C– Sn) values
for dimethyltin(IV) complex (2), dibutyltin(IV) complex (3) and
diphenltin(IV) complex (4) were observed to be 562.33, 548.45
and 552.34 Hz, respectively. Therefore, the J values confirmed the
penta-coordinate geometry about the tin(IV) atom [46]. Likewise,
the C–Sn–C angle of the diorganotin complexes can also be deter-
mined using the Lockhart–Manders equation h(C–Sn–C) =
1 13
| J( C–119Sn)| + 875]/11.4 and affords C–Sn–C angles of 126.08°,
[
1
24.86° and 125.20° for complexes 2, 3, 4, respectively. The calcu-
lated C–Sn–C angle values obtained from the NMR spectra show a
slight deviation from the Cphenyl–Sn–Cphenyl angle obtained from X-
ray diffraction studies of complex 4. The observed C–Sn–C angles
lies in the range 124.86–126.08°, which correspond to five-coordi-
nation of the tin atom in the complexes [47].
1
19
Sn NMR spectra provide valuable information to confirm the
119
coordination number around the tin.
Sn NMR spectra of all com-
plexes displayed one sharp single peak supporting the formation of
1
19
a single species.
Sn NMR chemical shifts of diorganotin(IV) com-
plexes (2–4) ranging from À177.08 to À169.22 ppm demonstrated
2
Fig. 2. The packing diagram of H cdet (1) in the crystal lattice. Intermolecular
hydrogen bonds are shown as dotted lines.
the five coordinated Sn atom [48,49].
3.5. X-ray crystallography diffraction analyses of H
2
cdet (1)
Table 1
Crystal data and structure refinement parameters for H
2
cdet (1) and [Ph
2
Sn(cdet)] (4).
The molecular structure of the free ligand H
2
cdet (1), together
with the atom numbering scheme and its packing in the crystal lat-
tice are shown in Figs. 1 and 2, respectively. Summary of crystal
data and structure refinement results, and selected bond lengths
Compound
2
H cdet (1)
[Ph Sn(cdet)] (4)
2
Empirical formula
Formula weight
T (K)
C
10
H
11Cl
2
N
3
OS
22 2 3
C H19Cl N OSSn
563.05
100
292.18
100
0.71073
triclinic
P–1
(
Å) and angles (°) are given in Tables 1 and 2, respectively. Based
on the molecular structure, the H cdet (1) remains in its tau-
tomeric thione form with S1 and N1 in the E configuration with
respect to the N2–C8 bond. The H cdet (1) exhibits the trans
k (Å)
0.71073
2
Crystal system
Space group
Unit cell dimensions
a (Å)
b (Å)
c (Å)
monoclinic
P2 /n
1
2
geometries of the S1 in relation to N1 atom. Furthermore, shows
the syn geometries of N1 in relation to N3 atom. This is confirmed
by the torsion angle of 176.97(12)° (N1–N2–C8–S1) [50]. The
observed bond lengths confirmed that the free ligand (1) exist in
thione form in the solid state. The bond distances of C8–S1 and
C8–N2 are 1.6945(16) Å and 1.362(2) Å, respectively. These bond
distances are closer to that expected of a C@S double bond
5.3023(2)
9.3655(3)
12.9787(5)
104.444(2)
95.345(2)
91.663(2)
620.51(4)
2
14.1937(7)
9.0137(5)
17.2872(9)
90.00
92.6314(9)
90.00
2209.4(2)
4
1.693
a
(°)
b (°)
(°)
c
3
V (Å )
Z
3
Calculated density (mg/m )
Radiation type k (Å)
F(000)
Crystal size (mm)
Crystal colour
1.564
(
1.60 Å) [51] than to C–S bond length (1.81 Å), and the C@N double
bond (1.28 Å) [52]. Similarly, the N1–N2 bond distance is
.3743(18) Å indicating the value is closer to the N–N single bond
Mo K/
300
a
Mo K/
1120
a
1
0.12 Â 0.23 Â 0.44
0.081 Â 0.303 Â 0.463
distance (1.45 Å) than the N@N double bond distance (1.25 Å) [51].
colorless
yellow
Scan range h (°)
2.3–30.0
0.677
2.87–30.22
1.513
Absorption coefficient (
l
)
À1
(
mm
)
Max. and min. transm
0.9238 and 0.7544
1.099
0.887 and 0.541
1.048
Goodness-of-fit (GOF) on F2
Data/restrains/parameters
3581/0/167
6522/0/276
Final R indices [I > 2
r
(I)]
R
1
= 0.0335,
wR = 0.0800
= 0.0429,
wR = 0.0869
R
1
= 0.0176,
wR = 0.0447
= 0.0190,
wR = 0.0455
2
2
R indices (all data)
R
1
R
1
2
2
The length, longer than usual of C@S and C@N points out the
extended conjugation in the molecule similar to other thiosemicar-
bazones. The above bond lengths indicate the 3,5-dichloro-2-hy-
2
droxybenzaldehyde-N(4)-ethylthiosemicarbazone (H cdet) exists
in the thione form in the solid state. The packing of the molecules
is stabilized by inter and intra-molecular hydrogen bonding
interactions in the crystal lattice. In the crystal packing, cen-
trosymmetrically related molecules associate into dimers via
Fig. 1. Molecular structure of 3,5-dichloro-2-hydroxybenzaldehyde-N(4)-ethylth-
iosemicarbazone [H cdet, (1)].
2

M.A. Salam, R.A. Haque / Inorganica Chimica Acta 435 (2015) 103–108
107
Table 2
2 2
Selected bond lengths (Å) and angles (°) of H cdet (1) and [Ph Sn(cdet)] (4).
Bond lengths (Å)
[
Ph
2
Sn(cdet)] (4)
2
H cdet (1)
Sn1–S1
Sn1–N1
Sn1–C17
O1–C1
N1–C7
N3–C8
C1–C2
Sn1–O1
S1–C8
N1–N2
N2 –C8
2.4955(4)
S1–C8
O1–C5
N1–C7
N1–N2
N2–C8
N3–C8
N3–C9
Cl1–C2
Cl2–C4
C1–C2
C1–C6
1.6945(16)
1.3487(19)
1.287(2)
1.3743(18)
1.362(2)
1.324(2)
2.2269(11)
2.1325(12)
1.3166(15)
1.3021(16)
1.3535(15)
1.4121(17)
2.0798(9)
1.7510(13)
1.3854(14)
1.3070(16)
1.467(2)
1.7406(16)
1.7370(16)
1.381(2)
1.394(2)
Bond angles (°)
[
Ph
2
Sn(cdet)] (4)
2
H cdet (1)
S1–Sn1–O1
S1–Sn1–C11
O1–Sn1–N1
O1–Sn1–C17
N1–Sn1–C17
Sn1–S1–C8
Sn1–N1–N2
S1–Sn1–N1
S1–Sn1–C17
O1–Sn1–C11
N1–Sn1–C11
C11–Sn1–C17
153.04(3)
105.16(4)
82.18(4)
88.75(4)
144.70(5)
96.18(4)
121.12(8)
78.22(3)
96.62(4)
97.29(4)
103.62(4)
111.36(5)
C7–N1–N2
C8–N2–N1
C8–N3–C9
C2–C1–C6
C1–C2–C3
C1–C2–Cl1
C3–C2–Cl1
C4–C3–C2
N1–C7–C6
N3–C8–N2
N3–C8–S1
N2–C8–S1
114.44(13)
121.24(14)
123.47(14)
119.76(15)
121.82(15)
119.16(13)
119.00(12)
118.13(14)
121.47(14)
117.25(14)
123.43(12)
119.32(12)
Fig. 3. Molecular structure of [Ph
2
Sn(cdet)] (4) showing displacement ellipsoids at
the 50% probability level.
C-H. . .O interactions and stack in columns along the b axis via p–p
interactions. There are two significant intermolecular H-bonding
contact involving the N3–HÁ Á ÁS1 and N2–HÁ Á ÁS1. On the other
hand, the one hydrogen atom of N3 and imine-N1 atoms are direc-
ted to the same side of the molecule enabling the formation of an
intramolecular N–HÁ Á ÁN hydrogen bond. Additionally, stabilization
is afforded by the C–H. . .
p and p. . .p [ring centroid(hydroxyben-
zene)] interactions.
3.6. X-ray crystallography diffraction analyses of [Ph
2
Sn(cdet)] (4)
The molecular structure of [Ph Sn(cdet)] (4) along with the
2
atomic numbering scheme is given in Fig. 3. Table 1 summarizes
crystal data and structure refinement results of compound 4.
Selected bond lengths (Å) and angles (°) are shown in Table 2.
Compound 4 crystallizes into a monoclinic lattice with space group
1
P2 /n. The crystal structure of the title complex 4 displayed that
the dianionic ligand is coordinated to the tin(IV) centre via the phe-
nolic-O, azomethine-N and thiolate-S atoms. Thus, molecular
structure of diphenyltin(IV) complex 4 confirmed that the central
tin(V) has a penta-coordinated geometry in distorted trigonal
bipyramidal arrangement. The meridional plane consists of the
azomethine nitrogen (N1) and two phenyl groups (C11, C17) from
the tin(IV) centre. The sum of the bond angles (N1–Sn1–C17)
Fig. 4. The packing diagram of [Ph
the a axis.
2
Sn(cdet)] (4) in the crystal lattice, viewed along
(
(
144.69(4)°), (C17–Sn1–C11) (111.36(5)°) and (C11–Sn1–N1)
103.62(4)°) is 359.61° showing that thiosemicarbazone portion
geometry is affected by strain force by the non-planar five and
six membered chelate rings, Sn1–S1–C8–N2–N1 and Sn1–O1–
C1–C6– C7–N1. The bond angles of C11–Sn1–C17 (111.36(5)°),
C11–Sn1–N1 (103.62(4)°) and C17–Sn1–N1 (144.69(4)°) for C11,
C17 and N1 are situated at the three edges of the trigonal plane.
So bond angles C11–Sn1–C17 and C17–Sn1–N1 are rather smaller
than 120° though C17–Sn1–N1 is little larger. This is most possibly
due to the repulsion induced by the two phenyls at tin(IV) centre.
Therefore, the geometric results indicate a strongly distorted trig-
onal bipyramidal arrangement around tin(IV) atom. The Sn1–N1
bond distance (2.22 Å) found to be close to the sum of the covalent
radii of Sn–N (2.15 Å) [53], is evidence that the azomethine nitro-
gen (N1) is bonded to the tin (Sn1) atom very tightly. The Sn1–O1
is in the same plane of tin(IV) centre. The axial positions are occu-
pied by the phenolic oxygen (O1) and thilate sulfur (S1) of the
ligand. The distorted trigonal bipyramidal geometry of complex 4
is evidenced from the largest bond angle containing the tin(IV)
atom O1–Sn1–S1 of (153.04(4)°), which deviated from the ideal
value of 180°. The bond angles of O1–Sn1–N1 is 82.18(4)° whereas
N1–Sn1–S1 is 78.22(3)° thus the sum of these two bond angles is
1
60.38° demonstrating deviation from the ideal value of 180°.
Most probably distortion is due to the involvement of the N1 atom
in the five member chelate rings, besides the large covalent radius
of tin(IV). The distortion from the ideal trigonal bipyramidal

1
08
M.A. Salam, R.A. Haque / Inorganica Chimica Acta 435 (2015) 103–108
bond distance (2.08 Å) is almost close to the covalent radii of Sn–O
2.10 Å) and comparable with those reported in articles [54,55].
The Sn1–S1 bond length (2.495 Å) was found close to the sum of
the covalent radii of Sn–S (2.42 Å) [56], indicating thiolate sulfur
bonded to the Sn moiety after deprotonation and is comparable
[11] K.C. Agrawal, A.C. Sartorelli, Prog. Med. Chem. 15 (1978) 321.
[
[
12] M.R. Maurya, A. Kumar, M. Abid, A. Azam, Inorg. Chim. Acta 359 (2006) 2439.
13] Z. Afrasiabi, E. Sinn, W. Lin, Y. Ma, C. Campana, S. Padhye, J. Inorg. Biochem. 99
(
(
2005) 1526.
[14] D.K. Saha, S. Padhye, E. Sinn, C. Newton, Indian J. Chem., Sect A 41 (2002) 279.
[
[
15] K. Alomar, M.A. Khan, M. Allain, G. Bouet, Polyhedron 28 (2009) 1273.
16] Z. Afrasiabi, E. Sinn, P.P. Kulkarni, V. Ambike, S. Padhye, D. Deobagakar, M.
Heron, C. Gabbutt, C.E. Anson, A. Powell, Inorg. Chim. Acta 358 (2005) 2023.
2
with the reported values for Sn–S (2.50 Å) in [Ph Sn(dact)] [57].
The two phenyl groups are bonded to the tin(IV) atom [Sn1–
C11 = 2.1269(12) Å, Sn1–C17 = 2.1326(12) Å which are slightly
shorter than the non-polar covalent radii of Sn–C (2.17 Å) [53],
but are comparable with other reported diorganotin(IV) complexes
[17] S.N. Pandeya, J.R. Dimmork, Pharmazie 48H–9 (1993) 659.
[
[
[
[
[
[
[
[
18] J.A. Zhang, M. Pan, J.J. Jiang, Z.G. She, Z.J. Fan, C.Y. Su, Inorg. Chim. Acta 374
2011) 269.
19] Z. Afrasiabi, E. Sinn, S. Padhye, S. Dutta, S. Padhye, C. Newton, C.E. Anson, A.K.
Powell, J. Inorg. Biochem. 95 (2003) 306.
(
20] J.A. Zhang, M. Pan, R. Yang, Z.G. She, W. Kaim, Z.J. Fan, C.Y. Su, Polyhedron 29
[
2
43,58]. The packing of the [Ph Sn(cdet)] (4) in the crystal lattice is
(
2010) 581.
shown in Fig. 4. The dimeric aggregates of the crystal structure are
made up of alternating layers that stack along the a direction and
21] I.C. Mendes, M.A. Soares, R.G. dos Santos, C. Pinheiro, H. Beraldo, Eur. J. Med.
Chem. 44 (2009) 1870.
22] V.V. Pavlishchuk, S.V. Kolotilov, A.W. Addison, R.J. Butcher, E. Sinn, J. Chem.
Soc., Dalton Trans. (2000) 335.
23] R.F.F. Costa, A.P. Rebolledo, T. Matencio, H.D.R. Calado, J.D. Ardisson, M.E.
Cortés, B.L. Rodrigues, H. Beraldo, J. Coord. Chem. 58 (2005) 1307.
24] M. Joseph, V. Suni, M.R.P. Kurup, M. Nethaji, A. Kishore, S.G. Bhat, Polyhedron
are connected by C–HÁ Á Á
. Conclusion
In conclusion, different analytical and spectral methods
p interactions.
4
23 (2004) 3069.
25] A.P. Rebolledo, M. Vieites, D. Gambino, O.E. Piro, E.E. Castellano, C.L. Zani, E.M.
Souza-Fagundes, L.R. Teixeira, A.A. Batista, H. Beraldo, J. Inorg. Biochem. 99
were used for the characterization of three new diorganotin(IV)
complexes of 3,5-dichloro-2-hydroxybenzaldehyde-N(4)-ethylth-
iosemicarbazone (H cdet). X-ray diffraction analysis of complex 4
2
reveals ONS coordination mode of the ligand (1) and displays the
existence of a distorted trigonal bipyramidal geometry around
the Sn(IV) atom. The NMR chemical shifts and X-ray crystallo-
graphic studies revealed that the diorganotin(IV) complexes are
five coordinated.
(
2005) 698.
26] T.D.S. Silva, L.R. Teixeira, R.L. Ziolli, S.R.W. Louro, H. Beraldo, J. Coord. Chem. 62
2009) 958.
[27] S. Padhye, Z. Afrasiabi, E. Sinn, J. Fok, K. Mehta, N. Rath, Inorg. Chem. 44 (2005)
154.
[
(
1
[
28] M.A. Hussein, T.S. Guan, R.A. Haque, M.B.K. Ahamed, A.M.S.A. Majid,
Polyhedron 85 (2015) 93.
[29] M.A. Hussein, T.S. Guan, R.A. Haque, M.B.K. Ahamed, A.M.S.A. Majid, Inorg.
Chim. Acta 421 (2014) 270.
[
[
[
[
[
30] V. Chandrasekhar, S. Nagendran, V. Baskar, Coord. Chem. Rev. 235 (2002) 1.
31] R. Garcia-Zarracino, J. Ramos-Quinones, H. Höpfl, Inorg. Chem. 42 (2003) 3835.
32] J.M. Tsangaris, D.R. Williams, Appl. Organomet. Chem. 6 (1992) 3.
33] L. Pellerito, L. Nagy, Coord. Chem. Rev. 224 (2002) 111.
34] G.F. de Sousa, R.H.P. Francisco, M.T. do P. Gambardella, R.H. de A. Santos, A.
Abras, J. Braz. Chem. Soc. 12 (2001) 722.
Acknowledgment
R.A.H. thanks Universiti Sains Malaysia (USM) for the Research
University (RU) Grant 1001/PKIMIA/811217. M.A.S. thanks USM
and World Academy of Sciences (TWAS) for a post-doctoral
research fellowship. We also thank the Bangladesh Petroleum
Exploration and Production Co. Ltd. (BAPEX), Bangladesh, for the
study leave to M.A. Salam.
[
35] T. Sedaghat, A. Golalzadeh, H. Motamedi, Phosphorus, Sulfur Silicon 188
(2013) 1694.
[
[
[
36] G.F. de Sousa, V.M. Deflon, L.C.C. Manso, Trans. Met. Chem. 32 (2007) 649.
37] G. Sheldrick, Acta Crystallogr. Sect. A 64 (2008) 112.
38] M. Ahmadi, J.T. Mague, A. Akbari, R. Takjoo, Polyhedron 42 (2012) 128.
[39] R.M. Silverstein, G.C. Bassler, T.C. Morrill, Spectrometric Identification of
Organic Compounds, fourth ed., Wiley, New York), 1981.
[
[
[
40] F.F. Costa, A.P. Rebolledo, T. Matencio, H.D.R. Calado, J.D. Ardisson, M.E. Cortes,
B.L. Rodrigues, H. Beraldo, J. Coord. Chem. 58 (2005) 1307.
41] M.A. Affan, M.A. Salam, F.B. Ahmad, J. Ismail, M.B. Samsuddin, H.M. Ali, Inorg.
Chim. Acta 366 (2011) 227.
42] I.C. Mendes, J.P. Moreira, A.S. Mangrich, S.P. Balena, B.L. Rodrigues, H. Beraldo,
Polyhedron 26 (2007) 3263.
Appendix A. Supplementary material
CCDC 885660 and 1050802 contains the supplementary
crystallographic data for [H cdet)] (1) and [Ph Sn(cdet)] (4).
2 2
These data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_
request/cif. Supplementary data associated with this article can
be found, in the online version, at http://dx.doi.org/10.1016/j.ica.
[43] H.D. Yin, S.W. Chen, L.W. Li, D.Q. Wang, Inorg. Chim. Acta 360 (2007) 2215.
[
44] M.A. Salam, M.A. Affan, F.B. Ahmad, M.A. Arafath, J. Coord. Chem. 65 (2012)
999.
45] M.F. Iskander, L. Labib, M.M.Z. Nour, M. Tawfik, Polyhedron 8 (1989) 2755.
1
[
[46] T.P. Lockhart, W.F. Manders, Inorg. Chem. 25 (1986) 892.
[
[
[
47] M. Nath, P.K. Saini, A. Kumar, J. Organomet. Chem. 695 (2010) 1353.
48] H.D. Yin, S.W. Chen, Inorg. Chim. Acta 359 (2006) 3330.
49] J. Holecek, M. Nadvornik, K. Handlir, A. Lycka, J. Organomet. Chem. 315 (1986)
299.
2
015.06.015.
References
[
[
[
[
50] D. Chattopadhyay, T. Banerjee, S.K. Mazumdar, S. Ghosh, R. Kuroda, Acta
Crystallogr. C 43 (1987) 974.
51] J.E. Huheey, E.A. Keiter, R.L. Keiter, Inorganic Chemistry, Principles of Structure
and Reactivity, fourth ed., Harper Collins College Publishers, New York, 1993.
52] J. March, Advanced Organic Chemistry, Reactions, Mechanisms and Structure,
fourth ed., Wiley, New York, 1992.
[
[
[
[
1] M. Nath, P.K. Saini, Dalton Trans. 40 (2011) 7077.
2] A.G. Davis, Organotin Chemistry, VCH Weinheim, Germany, 1997.
3] A.K. Saxena, F. Huber, Coord. Chem. Rev. 95 (1989) 109.
4] M. Gielen, E.R.T. Tiekink, Metallotherapeutic Drugs and Metal-Based
Diagnostic Agents: The Use of Metals in Medicine, Wiley, 2005.
5] M.B. Ferrari, F. Bisceglie, G. Pelosi, P. Tarasconi, R. Albertini, P.P.D. Aglio, S.
Pinelli, A. Bergamo, G. Sava, J. Inorg. Biochem. 98 (2004) 301.
6] Z. Afrasiabi, E. Sinn, J. Chen, Y. Ma, A.L. Rheingold, L.N. Zakharov, N. Rath, S.
Padhye, Inorg. Chim. Acta 357 (2004) 271.
7] E. Bermejo, R. Carballo, A. Castineiras, R. Dominguez, C.M. Mossmer, J. Strahle,
D.X. West, Polyhedron 18 (1999) 3695.
8] M.C.R. Argueelles, P.T. Touceda, R. Cao, A.M.G. Deibe, P. Pelagatti, C. Pelizzi, F.
Zani, J. Inorg. Biochem. 103 (2009) 35.
53] K.F. Purcell, J.C. Kotz, An Introduction to Inorganic Chemistry, Saunders College
Publishing, Orlando, USA, 1980.
[
[
[
[
[
[
[
54] H.D. Yin, F.H. Li, C.H. Wang, Inorg. Chim. Acta 360 (2007) 2797.
55] E. Labisbal, L. Rodriguez, A.S. Pedrares, M. Alonso, A. Vizoso, J. Romero, A.G.
Vazquez, A. Sousa, J. Organomet. Chem. 691 (2006) 1321.
56] J.S. Casas, A. Castineiras, E.G. Martinez, A.S. Gonzalez, A. Sanchez, J. Sordo,
Polyhedron 16 (1997) 795.
[
[
[
57] M.A. Affan, M.A. Salam, F.B. Ahmad, F. White, H.M. Ali, Inorg. Chim. Acta 387
(
2012) 219.
9] C. Shipman Jr., S.H. Smith, J.C. Drach, D.L. Klayman, Antiviral Res. 6 (1986) 197.
58] B. Sarkar, A.K. Choudhury, A. Roy, M. Biesemans, R. Willem, S.W. Ng, E.R.T.
Tiekink, Appl. Organometal. Chem. 24 (2010) 842.
[
10] J. Chen, Y. Huang, G. Liu, Z. Afrasiabi, E. Sinn, S. Padhye, Y. Ma, Toxicol. Appl.
Pharm. 197 (2004) 40.