Diorganotin(IV) complexes with acetone N(4)-phenylthiosemicarbazone (Haptsc) as ligand. The crystallographic structures of [Sn(CH3) 2(aptsc)X] (X=Cl and Br)

Article abstract of DOI:10.1016/j.molstruc.2003.08.009

The reaction of Haptsc with SnMe₂Cl₂ and SnMe ₂Br₂ yielded [Sn(CH₃)₂(aptsc)Cl] (1) and [Sn(CH₃)₂(aptsc)Br] (2), respectively. The complexes were characterized by IR an

Full text of DOI:10.1016/j.molstruc.2003.08.009

Journal of Molecular Structure 687 (2004) 17–21
www.elsevier.com/locate/molstruc
Diorganotin(IV) complexes with acetone N(4)-phenylthiosemicarbazone
(Haptsc) as ligand. The crystallographic structures
of [Sn(CH3)2(aptsc)X] (X ¼ Cl and Br)
a,
a
b
*
G.F. de Sousa , V.M. Deflon , E. Niquet
a
´ ´ ´
Instituto de Quımica, Universidade de Brasılia, 70919-970 Brasılia, DF, Brazil
b
¨ ¨ ¨ ¨
Institut fur Anorganische Chemie, Universitat Tubingen, D-72076 Tubingen, Germany
Received 27 May 2003; accepted 5 August 2003
Abstract
The reaction of Haptsc with SnMe2Cl2 and SnMe2Br2 yielded [Sn(CH3)2(aptsc)Cl] (1) and [Sn(CH3)2(aptsc)Br] (2), respectively. The
complexeswerecharacterizedbyIRandNMR(1H, 119Sn)spectroscopicmethods, elementalanalysisandX-raycrystal structuredetermination.
The X-ray study revealed that both complexes possess a trigonal bipyramidal geometry. (1) crystallizes in the orthorhombic crystal system,
ꢀ
ꢀ 3
space group P212121; with a ¼ 10:5157ð6Þ; b ¼ 12:2085ð15Þ; c ¼ 12:496ð3Þ A; V ¼ 1604:2 A and Z ¼ 4: (2) crystallizes in the monoclinic
ꢀ
ꢀ 3
crystal system, space group P21=c; with a ¼ 17:3253ð17Þ; b ¼ 7:2323ð6Þ; c ¼ 13:3527ð15Þ A; b ¼ 108:560ð10Þ8; V ¼ 1586:1 A and Z ¼ 4:
q 2003 Elsevier B.V. All rights reserved.
Keywords: Organotin(IV) complexes; Thiosemicarbazone complexes; Crystal and molecular structures
1. Introduction
The uniqueness of thiosemicarbazone (I) relates not only
to the presence of many electron donor centers in the
structure but also to the bonding scheme. Ten different
coordination fashion were already observed [3]. As a
bidentate ligand, it can coordinate anionically, either
bonding to the metal ion through the imine nitrogen and
the sulfur atoms (II), or via the hydrazinic nitrogen and the
sulfur atoms (III), forming five- and four-membered chelate
rings, respectively, [5,6]. The different coordination modes
(II and III) of (I) are related to the level of steric hindrance
caused by the bulk group R1 located in the trans position to
the hydrazinic nitrogen [5,6].
Thiosemicarbazones have attracted a crescent interest in
recent years due to their biological properties, such as
antiviral, antibacterial, antimalarial, antifungal and anti-
tumoral activities [1–3]. As ligands, they can behave as bi-,
tri-, tetra- and penta-coordinate chelating agents towards a
wide range of metallic ions, forming many structurally
different complexes [3]. The research on coordination
chemistry, analytical applications and biological activities
of thiosemicarbazones and its metallic derivatives has
increased considerably. A search on the Cambridge
Structure Database (CSD) showed more than thousand
papers published in the last decade [3,4].
The complexes (1) and (2) were synthesized as part of a
research program dedicated to the investigation of the
coordination modes of multidentate thiosemicarbazones
towards organotin(IV) compounds, namely SnMe2Cl2,
SnMe2Br2, SnnBu2Cl2, SnPh2Cl2 [7–10].
*
Corresponding author. Tel.: þ55-61-307-2150; fax: þ55-61-273-4149.
E-mail address: gfreitas@unb.br (G.F. de Sousa).
0022-2860/$ - see front matter q 2003 Elsevier B.V. All rights reserved.
doi:10.1016/j.molstruc.2003.08.009

18
G.F. de Sousa et al. / Journal of Molecular Structure 687 (2004) 17–21
2. Experimental
Table 1
Crystal data collection and structure refinement data for 1 and 2
2.1. Material and procedures
1
2
All starting compounds and reagents of highest grade
were used without further purification. IR spectra were
recorded in KBr pellets on a Bomen BM100 FT-IR
spectrometer in the 4000–400 cm21 region. 1H NMR
spectra were recorded in CD2Cl2 (SiMe4) and 119Sn NMR
spectra in CHCl3 (SnMe4) using a Bruker AC250 MHz and
a Varian Mercury Plus 300 MHz spectrophotometers,
respectively. A Carlo Erba 1104 elemental analyzer was
used for the microanalyses. X-ray data for structure
determination were collected on an Enraf-Nonius CAD-4
diffractometer.
Empirical
formula
Formula
weight
C
12H18ClN3SSn
C12H18BrN3SSn
434.95
390.49
208(2)
Temperature
(K)
208(2)
˚
Wavelength (A)
Crystal system
Crystal color
0.71073
0.71073
Orthorhombic
Colorless
Monoclinic
Colorless
0.45 £ 0.35 £ 0.20
P21=c
Crystal size (mm)
Space group
0.60 £ 0.25 £ 0.15
P212121
Z, calculated
density (g cm23
4, 1.617
4, 1.821
)
Absorption coefficient
(mm21
˚
a (A)
˚
b (A)
˚
c (A)
1.877
4.249
)
2.1.1. Preparation of Haptsc
10.5157(6)
12.2085(15)
12.496(3)
90.000
17.3253(17)
7.2323(6)
13.3527(15)
108.560(10)
1586.1(3)
848
The thiosemicarbazone Haptsc was prepared by reacting
equimolar amounts of N(4)-phenylthiosemicarbazide (1 g,
6 mmol) and acetone (0.4 g, 7 mmol) in 20 ml of a 1:1
ethanol–water mixture under reflux for 30 min. After
cooling, 0.8 g of the ligand was obtained as a white solid,
which was filtered off and dried under vacuum over CaCl2.
Yield 64% (0.8 g, 3.8 mmol). Mp 125–127 8C.
b (8)
3
˚
V (A )
1604.2(4)
776
F(000)
Theta range for
data collection (8)
Limiting indices
3.03–28.00
3.06–27.97
213 # h # 13
21 # k # 16
21 # l # 16
4940/3858
222 # h # 22
29 # k # 1
21 # l # 17
4935/3807
2.1.2. Preparation of [Sn(CH3)2(aptsc)Cl] (1) and
[Sn(CH3)2(aptsc)Br] (2)
Reflections
collected/unique
Completeness
to theta
[R(int) ¼ 0.0202]
28.00(99.8%)
[R(int) ¼ 0.0256]
27.97(99.9%)
The halogen complexes were synthesized by refluxing
Haptsc (0.2 g, 0.97 mmol) and the appropriate SnMe2X2
(0.97 mmol) in 15 ml of EtOH for 1 h. The reaction mixture
was then filtered to give a clear solution. The products were
isolated as white solids by slow evaporation of the mother
solution. Anal. Calcd for C12H18ClN3SSn (1): C 36.81, H
4.86, N 10.74, S 8.19. Found C 36.84, H 4.07, N 10.89, S
Refinement method
Full-matrix
least-squares
on F 2
Full-matrix
least-squares
on F 2
Data/restraints/
parameters
Goodness-of-fit on F 2
Final R indices
[I . 2s(I)]
3858/0/235
3807/0/236
1.087
1.046
1
7.89. H NMR d 1.1 [s, 6H, Sn(CH3)2], 2.2 and 2.1 [s, 6H,
R1 ¼ 0.0208,
wR2 ¼ 0.0533
R1 ¼ 0.0218,
wR2 ¼ 0.0538
0.321 and 2 0.885
R1 ¼ 0.0252,
wR2 ¼ 0.0548
R1 ¼ 0.0386,
wR2 ¼ 0.0588
0.490 and 2 0.537
NyC(CH3)2] and 7.4, 7.2, 7.0, 6.6 (m, 5H, C6H5). 119Sn
NMR d 280. Yield 63% (1.2 g, 3.1 mmol). Mp 175 8C (d).
Anal. Calcd for C12H18BrN3SSn (2): C 33.05, H 4.36, N
´
R ındices (all data)
Largest diff.
˚
Peak and hole (eA
1
23
9.64, S 7.34. Found C 33.10, H 4.46, N 9.74, S 7.19. H
)
NMR d 1.2 [s, 6H, Sn(CH3)2], 2.2 and 2.1 [s, 6H,
NyC(CH3)2] and 7.4, 7.2, 7.0, 6.6 (m, 5H, C6H5). 119Sn
NMR d 279. Yield 76% (1.6 g, 3.7 mmol). Mp 195–
197 8C.
performed for corrections [11]. More detailed information
about the crystal structure determination is given in Table 1.
Table 2 presents selected bond lengths and angles. Labeled
diagrams of (1) and (2) are shown in Figs. 1 and 2,
respectively.
2.2. Crystal structure determinations
Suitable crystals for structural analysis for both com-
plexes were obtained by slow evaporation of the refluxed
solutions. The cell constants were calculated from 25
reflections measured with a wide range of 2u: The program
HELENA [11] was used for data reduction. The structures
were solved using the heavy atom method, with the program
SHELXS-97 [12]. All non-hydrogen atoms were refined
anisotropycally with SHELXL-97 [13] and the hydrogen
atoms were found in the Fourier-Map for both complex
structures. A semi-empirical c-scans absorption was
3. Results and discussion
3.1. Infrared spectroscopy
The main stretching bands for Haptsc and their
complexes are shown in Table 3. The two high frequency
bands of the free ligand, centered at 3249 and 3170 cm21
,

G.F. de Sousa et al. / Journal of Molecular Structure 687 (2004) 17–21
19
Table 2
˚
Selected bond lengths (A) and angles (8) for 1 and 2
compared to (2) (3374 cm21), might be a consequence of
the intermolecular hydrogen bond N(3)–H(3)· · ·Cl
observed in (1). This situation is not realized in (2),
although similar results can be found in the literature [7–10,
14–17].
1
2
Sn–C(9)
Sn–C(10)
Sn–N(1)
Sn–S
2.123(3)
2.117(3)
2.328(2)
2.4192(8)
2.5242(8)
1.771(2)
1.293(3)
1.295(3)
1.360(3)
1.391(3)
3.292(2)
2.43(4)
2.116(3)
2.121(3)
2.359(2)
2.4467(7)
2.6559(4)
1.764(3)
1.287(3)
1.293(3)
1.374(3)
1.397(3)
Significant changes in the ligand bonds upon complexa-
tion include variations in the nðCyCÞ þ nðCyNÞ and nðC–
SÞ þ nðC–NÞ vibrational frequencies to lower values. These
data has been a good indication of coordination through the
azomethine nitrogen and the sulfur atoms [7,8,10].
Sn–Xa
C(2)–S
C(1)–N(1)
C(2)–N(2)
C(2)–N(3)
N(1)–N(2)
N(3)· · ·Clb
H(3)· · ·Clb
3.2. NMR spectroscopy
1
The H NMR spectrum of (1) has showed an isolated
singlet at d 1.1 [2J(119Sn–CH3) ¼ 81 Hz] and a pair of
singlets at d 2.2 and 2.1, which suggest that the methyl
groups NyC(CH3)2 are magnetically non-equivalent. The
spectrum of (2) showed similar signals at d 1.2 [2J(119Sn–
CH3) ¼ 75 Hz] and d 2.2 and 2.1. The use of Lockhart-
Manders equation {u ¼ 0.0161 [2J(119Sn–CH3)]2 2 1.32
[2J(119Sn–CH3)] þ 133.4} [18] with the observed coupling
constants of 81 and 75 Hz results in CH3–Sn–CH3 bond
angles of 1258 in (1) and 1328 in (2). These values fairly
accurate to the angles observed in their crystal structures,
129.26(16)8 in (1) and 135.59(16)8 in (2), indicating that the
structural arrangement of the complexes in the solid state
are retained in solution. A similar result was reported for
[Sn(CH3)2(DAP4P)] (H2DAP4P, 2-hydroxyacetophenone-
N(4)-phenylthiosemicarbazone) [19].
C(9)–Sn–C(10)
C(9)–Sn–N(1)
C(10)–Sn–N(1)
C(9)–Sn–Xa
C(10)–Sn–Xa
N(1)–Sn–Xa
C(9)–Sn–S
129.26(16)
93.87(11)
92.68(11)
92.31(10)
93.55((10)
165.50(5)
115.67(12)
114.92(11)
78.13(5)
135.59(16)
93.73(13)
89.41(11)
95.00(11)
93.56(10)
164.14(5)
110.12(12)
113.70(9)
76.83(5)
C(10)–Sn–S
N(1)–Sn–S
S–Sn–Xa
87.38(3)
87.729(19)
128.8(2)
N(2)–C(2)–S
C(2)–N(3)–C(3)
N(3)–H(3)–Clb
128.17(19)
128.8(2)
127.5(2)
178(3)
a
X ¼ Cl in 1 and Br in 2.
b
Symmetry operation: 2x þ 3=2; 2y þ 2; z 2 1=2:
The 119Sn NMR chemical shift is very sensitive to
complexation and usually greatly shifted downfield or
upfield on bonding to a Lewis base. The upfield chemical
shift values of 280 and 279 ppm observed for compounds
(1) and (2), respectively, are indicative of considerable
shielding and five-coordination of the Sn(IV) nucleus [20].
were attributed to n(N–H) stretching. The spectra of both
complexes lack bands located at about 3170 cm21, as a
result of the ligand deprotonation, indicating that this
absorption refer to the n(Nhydrazinic–H) vibration. The lower
position of the n(Naminic–H) absorption in (1) (3307 cm21
)
Fig. 1. ORTEP diagram of [Sn(CH3)2(aptsc)Cl] (1) showing three complex molecules linked through intermolecular hydrogen bonds, showed as dashed lines.
Displacement ellipsoids are drawn at the 50% probability level. Except H(3), the H atoms are omitted for clarity.

20
G.F. de Sousa et al. / Journal of Molecular Structure 687 (2004) 17–21
The considerable values for the Sn–S and Sn–C bond
˚
distances found in both complexes, 2.433 and 2.119 A, are
in agreement with those previously reported for organoti-
n(IV) thiolates containing bidentate ligands [14,15].
˚
The distances Sn–N(1) [2.328(2) A in (1) and
˚
2.359(2) A in (2)] are remarkable close to the value of
˚
2.359(4) A found in [Sn(CH3)2(FPT)Cl]·0.5H2O, where
HFTP is 2-formylpyridinethiosemicarbazone. The sulfur
and nitrogen atoms are bonded to the Sn(IV) core in the
latter forming a five-membered chelate ring [16]. On the
˚
other hand, the distances Sn–Cl ¼ 2.5242(8) A and Sn–
˚
Br ¼ 2.6559(4) A are shorter than the values of 2.6722(9)
˚
and 2.9075(6) A, found in Sn(IV) hexacoordinate com-
plexes, namely [Sn(CH3)2(AP4P)Cl] and [Sn(CH3)2
(AP4P)Br], where HAP4P is 2-acetylpyridine N(4)-phe-
nylthiosemicarbazone [10].
The average equatorial angles S–Sn–C(9) (112.98), S–
Sn–C(10) (114.38) and C(9)–Sn–C(10) (132.48) as well as
the axial angles N(1)–Sn–X (164.88) are quite different
from the equivalent angles found in [Sn(CH3)2
(FPT)Cl]·0.5H2O [108.3(2), 107.2(2), 143.0(3) and
155.39(9)8, as a result of the Sn· · ·N(py) intermolecular
interaction present in the latter [16].
Fig. 2. ORTEP diagram of [Sn(CH3)2(aptsc)Br] (2). Displacement
ellipsoids are drawn at the 50% probability level. The H atoms are omitted
for clarity.
These chemical shift values are comparable to a 292 ppm
for [Sn(CH3)2(OX)Cl], where HOX is 8-hydroxyquinoline
[20] and to a 2104.7 ppm for [Sn(CH3)2L], where H2L is
salicylaldehydehydethiosemicarbazone [21]. The 119Sn
NMR chemical shifts for SnMe2Cl2 and SnMe2Br2 has
taken place at 137 and 72 ppm, suggesting that the five-
coordination pattern in the solid state has remained in
CDCl3 solution.
The chelate ring atoms Sn, N(1), N(2), C(2), S, and N(3)
inclusive, are coplanar with a mean deviation from the plane
˚
˚
of 0.0226 A in (1) and of 0.0017 A in (2). The angle
between this plane and the phenyl ring formed by the atoms
C(3), C(4), C(5), C(6), C(7) and C(8) has 25.1(1)8 in (1) and
33.5(1)8 in (2).
The crystal structures of (1) and (2), differ from each
other mainly by their packing mode, what can be clearly
distinguished in the crystallization systems. The structure of
(1) has presented intermolecular N(3)–H(3)· · ·Cl hydrogen
bonds, forming a one-dimensional chain, as shown in Fig. 1.
The latter is directed along the crystallographic c axis, with
3.3. Crystal structures
The geometry around the Sn(IV) center in both
complexes is best described as a distorted trigonal
bipyramid (TBP), with the sulfur atom and the two methyl
carbons, C(9) and C(10), positioned at the equatorial
plane, while the azomethyne nitrogen N(1) and halogen
[Cl in (1) and Br in (2)] atoms are occupying the axial
positions.
˚
˚
N(3)· · ·Cl ¼ 3.292(2) A, H(3)· · ·Cl ¼ 2.43(4) A and N(3)–
H(3)–Cl ¼ 178(3)8. Such an interaction does not occur
in (2).
4. Supplementary data
Table 3
Main vibration bands (cm21) of Haptsc and its complexes
Crystallographic data for the structural analysis of
complexes (1) and (2) have been deposited at the Cambridge
Crystallographic Data Center, 12 Union Road, Cambridge,
CB2 1 EZ, UK, and are available free of charge from the
Director on request quoting the deposition numbers CCDC
203905 and 203906, respectively (Fax: þ44-1223-336033,
e-mail: deposit@ccdc.cam.ac.uk).
Compound
Haptsc
n(N–H) n(CyC) þ n(CyN) n(C–S) þ n(C–N) n(CyS)
3249s
1593m,
1537s
1382w, 1342m
1193s
3170m 1495m,
1443m
[Sn(CH3)3
3307s
3374s
1557s,
1516s
1497m,
1438s
1364m
1187w
1188m
(aptsc)Cl] (1)
Acknowledgements
[Sn(CH3)3
1548s,
1501s
1435s
1360w
The authors are grateful to Professor Dr H.C. Joaquim
(aptsc)Br] (2)
¨
Strahle (Tubingen) for providing laboratory facilities and
CNPq and FINEP (INFRA n8 0970/01) for financial support.
¨

G.F. de Sousa et al. / Journal of Molecular Structure 687 (2004) 17–21
21
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