Investigation on steric effect in the coordination of S, N and O donor heterocycle to organotin(IV): Syntheses and crystal structures of triorganotin(IV) derivatives with 5-phenyl-1,3,4-oxadiazole-2-thiol

Article abstract of DOI:10.1016/j.poly.2005.05.012

A series of organotin(IV) complexes with 5-phenyl-1,3,4-oxadiazole-2-thiol of the type R₃Sn[S(C₈H₅N₂O)] (R = Me 1, n-Bu 2, PhCH₂ 3, Cy 4, Ph 5) have been synthesized. All the complexes 1-5 have been characterized by elemental, IR, ¹H NMR, ¹³C NMR analyses and X-ray crystallography. Among them, the central tin atoms of complexes 1-5 are all five-coordinated with distorted trigonal bipyramidal geometry. Interestingly, complexes 1-4 exhibit 1D polymeric chains through Sn and N intermolecular interactions.

Full text of DOI:10.1016/j.poly.2005.05.012

Polyhedron 24 (2005) 1773–1780
www.elsevier.com/locate/poly
Investigation on steric effect in the coordination of S, N and O
donor heterocycle to organotin(IV): Syntheses and crystal
structures of triorganotin(IV) derivatives with
5-phenyl-1,3,4-oxadiazole-2-thiol
a,b,
a
a
Chun-Lin Ma
*, Guang-Ru Tian , Ru-Fen Zhang
a
Department of Chemistry, Liaocheng University, 34 Wenhua Road, Liaocheng 252059, PR China
b
Taishan University, Taian 271021, PR China
Received 26 March 2005; accepted 24 May 2005
Available online 14 July 2005
Abstract
A series of organotin(IV) complexes with 5-phenyl-1,3,4-oxadiazole-2-thiol of the type R3Sn[S(C8H5N2O)] (R = Me 1, n-Bu 2,
PhCH2 3, Cy 4, Ph 5) have been synthesized. All the complexes 1–5 have been characterized by elemental, IR, 1H NMR, 13C
NMR analyses and X-ray crystallography. Among them, the central tin atoms of complexes 1–5 are all five-coordinated with dis-
torted trigonal bipyramidal geometry. Interestingly, complexes 1–4 exhibit 1D polymeric chains through Sn and N intermolecular
interactions.
ꢀ 2005 Elsevier Ltd. All rights reserved.
Keywords: 5-Phenyl-1,3,4-oxadiazole-2-thiol; Triorganotin(IV); Crystal structures; Steric effect
1. Introduction
heterocyclic thioamide group (N–C–S)ꢀ. The X-ray
analyses have revealed that the former act as thiol form
but the primary bond of the latter two ligands to the tin
atom varies dramatically according to distinct R of the
precursor RnSnCl4 ꢀ n [7–10]. These results indicate that
several factors can influence the topologies of the
organotin derivatives from heterocyclic thionates such
as the special geometries of ligand, the spacial resistant
from R, etc. To continue our studies in this field, we
choose another fascinating heterocyclic thionate: 5-phe-
nyl-1,3,4-oxadiazole-2-thiol, which possesses one –SH
group, through which primary bonds to tin atoms are
likely formed. Furthermore, the potential coordination
nitrogen and oxygen atoms of the oxadiazole ring make
the ligand act as a fulcrum through which lattice con-
struction is orchestrated in one or more dimensions.
In this paper, we report some details of the synthe-
ses and characterizations of five triorganotin(IV) com-
plexes with the ligand of the type R3Sn[S(C8H5N2O)]
Increasing investigation of organotin(IV) complexes
has been focused on acquiring well-defined solid-state
structures to learn the nature of their versatile coordina-
tion chemistry [1–3], especially those organotin(IV)
derivatives from heterocyclic thionates containing a
nitrogen atom (or more) and an adjacent, exocyclic thio-
keto group [4–6]. A characteristic feature of these com-
plexes in the solid state is that the ligands chelate the tin
atom through S and N atoms. In our previous work, we
studied the coordination chemistry of three ligands of
such kind: 2-mercaptonicotinic acid, 1-(4-hydroxyphe-
nyl)-1H-tetrazole-5-thiol and 2,5-dimercapto-1,3,4-thio-
diazole which possess one or two deprotonated
*
Corresponding author. Tel.: +86 635 8238121; fax: +86 538
6715521.
E-mail address: macl@lctu.edu.cn (C.-L. Ma).
0277-5387/$ - see front matter ꢀ 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2005.05.012

1774
C.-L. Ma et al. / Polyhedron 24 (2005) 1773–1780
(R = Me 1, n-Bu 2, PhCH2 3, Cy 4, Ph 5). The X-ray
crystallography data show that the tin atoms of com-
plexes 1–5 are all five-coordinated with distorted trigo-
nal bipyramidal geometry. Interestingly, complexes 1–
4 exhibit 1D polymeric chains through Sn and N
intermolecular interactions.
2.2.2. (n-Bu)3Sn[S(C8H5N2O)] (2)
Yield, 74%; m.p. 69–72 ꢁC. Anal. Calc. for
C20H32N2OSSn: C, 51.41; H, 6.90; N, 6.00. Found: C,
1
51.50; H, 6.70; N, 6.22%. H NMR (CDCl3): d 7.25–
7.82 (m, 5H, C6H5–C), 0.85–1.68 (s, 27H, Sn–C4H9)
ppm. 13C NMR: d 145.6 (C-1 ligand), 136.5 (C-2),
136.5 (C-20), 128.3 (C-3), 128.3 (C-30), 129.4 (C-4),
168.3 (C–S), 168.8 (C–Ph), 13.5, 26.3, 27.5, 29.2 (n-Bu)
ppm. IR (KBr, cmꢀ1): m(C@N) 1586, m(Sn–C)as 528,
m(Sn–C)s 502, m(Sn–S) 315, m(Sn–N) 485.
2. Experimental
2.1. Materials and measurements
2.2.3. (PhCH2)3Sn[S(C8H5N2O)] (3)
Yield, 76%; m.p. 125–127 ꢁC. Anal. Calc. for
C29H26N2OSSn: C, 61.18; H, 4.60; N, 4.92. Found: C,
Trimethyltin chloride, tri-n-butyltin chloride, triphe-
nyltin chloride, tricyclohexyltin chloride and 5-phenyl-
1,3,4-oxadiazole-2-thiol were commercially available,
and they were used without further purification. Triben-
zyltin chloride was prepared by a standard method re-
ported in the literature [11]. The melting points were
obtained with Kofler micro melting point apparatus
and are uncorrected. Infrared-spectra were recorded
on a Nicolet-460 spectrophotometer using KBr discs
1
61.05; H, 4.41; N, 4.80%. H NMR (CDCl3): d 7.31–
7.47 (m, 5H, C6H5–C), 6.91–7.17 (m, 15H, Sn–
CH2C6H5), 2.76 (s, 6H, Sn–CH2C6H5). 13C NMR: d
145.5 (C-1 ligand), 136.4 (C-2), 136.4 (C-20), 128.2 (C-
3), 128.2 (C-30), 129.3 (C-4), 168.1 (C–S), 168.6 (C–
Ph), 37.4 (CH2–Ph), 127.5 (m-C), 128.7 (p-C), 127.6 (o-
C), 124.5 (i-C) ppm. IR (KBr, cmꢀ1): m(C@N) 1596
m(Sn–C)as 460, m(Sn–C)s 437, m(Sn–S) 308, m(Sn–N) 484.
1
and sodium chloride optics. H and 13C NMR spectra
were recorded on Varian Mercury Plus 400 spectrometer
operating at 400 and 100.6 MHz, respectively. The spec-
tra were acquired at room temperature (298 K) unless
otherwise specified; 13C spectra are broadband proton
decoupled. The chemical shifts were reported in ppm
with respect to the references and were stated relative
to external tetramethylsilane (TMS) for 1H and 13C
NMR. Elemental analyses were performed with a PE-
2400II apparatus.
2.2.4. Cy3Sn[S(C8H5N2O)] (4)
Yield, 77%; m.p. 120–121 ꢁC. Anal. Calc. for
C26H38N2OSSn: C, 57.26; H, 7.02; N, 5.14. Found: C,
1
57.15; H, 7.11; N, 5.05%. H NMR (CDCl3): d 7.21–
7.41 (m, 5H, C6H5–C), 0.82–1.65 (m, 33H, Sn–C6H33).
13C NMR: d 145.3 (C-1 ligand), 136.2 (C-2), 136.2 (C-
20), 128.2 (C-3), 128.2 (C-30), 129.2 (C-4), 168.3 (C–S),
168.6 (C–Ph), 26.6 (m-C), 26.5 (p-C), 26.8 (o-C), 27.5
(i-C) ppm. IR (KBr, cmꢀ1): m(C@N) 1592, m(Sn–C)as
450, m(Sn–C)s 427, m(Sn–S) 307, m(Sn–N) 483.
2.2. Syntheses of the complexes 1–5
The general route of synthesis is shown in the follow-
ing. The reaction was carried out under nitrogen atmo-
sphere. The 5-phenyl-1,3,4-oxadiazole-2-thiol (1 mmol)
was added to the solution of benzene 20 ml with sodium
ethoxide (1 mmol), then add R3SnCl (1 mmol) to the
mixture, continuing the reaction for 12 h at 40 ꢁC. After
cooling down to the room temperature, the solution was
filtered. The solvent of the filtrate was gradually removed
by evaporation under vacuum until solid product was
obtained. The solid was then recrystallized from dichlo-
romethane-n-hexane. Colorless crystal was formed.
2.2.5. Ph3Sn[S(C8H5N2O)] (5)
Yield, 75%; m.p. 185–187 ꢁC. Anal. Calc. for
C26H20N2OSSn: C, 59.23; H, 3.82; N, 5.31. Found: C,
1
59.11; H, 3.71; N, 5.22%. H NMR (CDCl3): d 7.21–
7.42 (m, 5H, C6H5–C), 7.45–7.76 (m, 15H, Sn–C6H5)
ppm. 13C NMR: d 145.2 (C-1 ligand), 136.3 (C-2),
136.3 (C-20), 128.1 (C-3), 128.1 (C-30), 129.1 (C-4),
168.0 (C–S), 168.5 (C–Ph), 127.9 (m-C), 129.0 (p-C),
136.4 (o-C), 148.5 (i-C) ppm. IR (KBr, cmꢀ1): m(C@N)
1590, m(Sn–C)as 464, m(Sn–C)s 429, m(Sn–S) 311.
2.3. X-ray crystallographic studies of complexes 1–5
2.2.1. Me3Sn[S(C8H5N2O)] (1)
Yield, 70%; m.p. 116–118 ꢁC. Anal. Calc. for
C11H14N2OSSn: C, 38.74; H, 4.14; N, 8.21. Found: C,
Crystals were mounted in Lindemann capillaries un-
der nitrogen. All X-ray crystallographic data were col-
lected on a Bruker SMART CCD 1000 diffractometer
with graphite monochromated Mo Ka radiation
1
38.65; H, 4.04; N, 8.10%. H NMR (CDCl3): d 7.24–
7.83 (m, 5H,C6H5–C), 0.76 (s, 9H, Sn–CH3) ppm. 13C
NMR: d 145.7 (C-1 ligand), 136.6 (C-2), 136.6 (C-20),
128.4 (C-3), 128.4 (C-30), 129.5 (C-4), 168.2 (C–S),
168.7 (C–Ph), 8.11 (Me) ppm. IR (KBr, cmꢀ1):
m(C@N) 1584, m(Sn–C)as 530, m(Sn–C)s 504, m(Sn–S)
313, m(Sn–N) 486.
˚
(k = 0.71073 A) at 298(2) K. A semi-empirical absorp-
tion correction was applied to the data. The structure
was solved by direct methods using SHELXS-97 and re-
fined against F2 by full-matrix least squares using
SHELXL-97. Hydrogen atoms were placed in calculated

C.-L. Ma et al. / Polyhedron 24 (2005) 1773–1780
1775
Table 1
Crystal data and structure refinement parameters for complexes 1–5
Complexes
1
2
3
4
5
Empirical formula
Formula weight
Crystal system
C11H14N2OSSn
340.99
C20H32N2OSSn
467.23
triclinic
C29H26N2OSSn
569.27
C26H38N2OSSn
543.32
C26H20N2OSSn
527.19
monoclinic
P21/m
orthorhombic
P212121
monoclinic
P21/c
monoclinic
P21/n
ꢀ
Space group
Unit cell dimensions
P1
˚
a (A)
6.891(3)
7.509(4)
13.354(7)
90
10.56(1)
12.55(1)
18.31(2)
88.42(1)
75.27(1)
87.48(1)
2345(5)
6.789(2)
19.326(6)
19.896(6)
90
12.603(1)
12.549(1)
19.818(1)
90.00
10.82(4)
12.97(5)
16.43(6)
90
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
104.723(5)
90
90
90
125.503(4)
90.00
101.92
90
2257(1)
3
˚
V (A )
668.2(6)
2
1.695
2610(1)
4
1.449
2551.5(4)
4
1.414
Z
4
1.324
4
1.552
Dc (Mg mꢀ3
)
Absorption coefficient (mmꢀ1
F(0 0 0)
Crystal size (mm)
)
2.050
336
1.188
960
1.082
1152
1.103
1120
1.245
1056
0.37 · 0.28 · 0.21
3.06–25.02
2792
0.48 · 0.46 · 0.16
1.62–25.03
11 766
0.44 · 0.25 · 0.21
1.47–25.03
13 718
0.20 · 0.18 · 0.13
2.298–27.983
28 636
0.48 · 0.41 · 0.36
2.07–25.05
10 466
h Range (ꢁ)
Reflections collected
Independent reflections [Rint
Data/restraints/parameters
Goodness-of-fit onF2
]
1028 [0.0203]
1028/9/100
1.026
8112 [0.0309]
8112/30/451
0.997
4571 [0.0294]
4571/0/307
1.002
5812 [0.0274]
5812/0/0280
1.045
3638 [0.1630]
3638/0/280
1.008
Final R indices [I > 2r(I)]
R1 = 0.0503
wR2 = 0.1392
R1 = 0.0508
wR2 = 0.1400
R1 = 0.0491
wR2 = 0.1154
R1 = 0.0963
wR2 = 0.1438
R1 = 0.0263
wR2 = 0.0526
R1 = 0.0312
wR2 = 0.0547
0.0343
0.0858
R1 = 0.0739
wR2 = 0.1483
R1 = 0.1120
wR2 = 0.1722
R indices (all data)
0.0410
0.0906
positions. Crystal data and experimental details of the
structure determinations are listed in Table 1.
cating metal–ligand bond formation through this site. In
the far-IR spectra, the absorption about 310 cmꢀ1
region for all complexes 1–5, which is absent in the spec-
trum of the ligand, is assigned to the Sn–S stretching
mode of the vibration and all the values are located
within the range for Sn–S vibration observed in com-
3. Results and discussion
3.1. Syntheses of complexes 1–5
mon organotin derivatives of thiolate (300–400 cmꢀ1
)
[12,13]. In organotin complexes, the IR spectra can pro-
vide useful information concerning the geometry of the
SnCn moiety [14]. In the case of our complexes, for
triorganotin(IV) derivatives, two bands were assigned
to asymmetric and symmetric Sn–C vibrations. Thus
suggesting non-planar SnC3 fragments for triorganotins.
The middle intensity bands observed at about
1600 cmꢀ1 in the spectra of all complexes have been
assignable to m(C@N) according to the literatures
[15,16], which suggested the coordination of free ligand
to these complexes is through sulfur atoms via thiol
form.
The synthesis procedure is given in Scheme 1.
3.2. IR spectroscopic studies of complexes 1–5
Comparing the IR spectra of the free ligand with
complexes 1–5, the band at 2560–2430 cmꢀ1, which ap-
pears in the spectra of the free ligand as the m(S–H)
vibration, is absent in those of complexes 1–5 thus indi-
R
S
N
N
Sn
O
1
3.3. H and 13C NMR data of complexes 1–5
R
R
N
N
n
EtONa
1H NMR data showed that the signal of the –SH pro-
ton in the spectrum of the ligand is absent in all of the
complexes, indicating the removal of the –SH proton
and the formation of Sn–S bonds. The formation ac-
cords well with what the IR data have revealed. More-
over, the 1H NMR spectra show that the chemical
shifts of the phenyl group (Sn–C6H5) in complex 5,
SH
O
+ R3SnCl
R = Me 1, n-Bu 2, PhCH2 3, Cy 4
Ph
Ph
N
N
Sn
O
S
Ph
5
Scheme 1.

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C.-L. Ma et al. / Polyhedron 24 (2005) 1773–1780
7.45–7.76 ppm, and those of methylene connected di-
rectly with tin in complex 3, 2.76 ppm, upfield shift as
compared with those of their corresponding precursors.
All these data are similar to those cases in literature [17],
indicating there may exist novel coordination of the li-
gand to tin atom for all the five complexes 1–5. In addi-
tion, the resonance of the phenyl group connected with
the oxadiazole ring (C–C6H5) appears at 7.21–7.83 ppm
for all complexes 1–5.
The structural changes occurring in ligand upon
deprotonation and coordination to the Sn atom should
be reflected by the changes in the 13C NMR spectra of
our complexes. If the ligand chelate tin through thiolate
form, C–S should be further low frequency in the spec-
tra of all complexes compared with those in free ligands.
As shown above, the chemical shifts of C–S in com-
plexes 1–5 are shifted by 8 ppm to low frequency com-
pared with the free ligand (d 176.2 ppm), indicating
that the ligands involved in these complexes act as
thiolate form. All of the above analyses are confirmed
by X-ray diffraction.
Fig. 2. Perspective view showing the 1D polymeric chain of the
complex 1.
3.4. Crystal structures of complexes 1–5
The crystal structures and polymeric chains of com-
plexes 1–4 are shown in Figs. 1–8, respectively. And
the crystal structure and cell packing diagram of com-
plex 5 are shown in Figs. 9 and 10. All H atoms have
been omitted for the purpose of clarity. Table 1 lists
the crystal data and structure refinement parameters
for complexes 1–5 and their selected bond lengths and
angles are shown in Tables 2–6, respectively.
Fig. 3. Molecular structure of the complex 2.
3.4.1. Me3Sn[S(C8H5N2O)] (1), (n-Bu)3Sn[S(C8H5-
N2O)] (2), (PhCH2)3Sn[S(C8H5N2O)] (3) and
Cy3Sn[S(C8H5N2O)] (4)
For complexes 1–4, the X-ray diffraction investiga-
tion has shown that they exhibit 1D polymeric chains
through intermolecular Sn–N bonds. The central tin
atoms in complexes 1–4 are all five-coordinate with
the trans-trigonal–bipyramidal geometry. The methyl
Fig. 4. Perspective view showing the 1D polymeric chain of the
complex 2.
carbons in complex 1, the methylene carbons which
are next to tin in complex 2, the methylene carbons
in complex 3 and the –CH– carbons in complex 4 are
in equatorial positions and the axial positions are occu-
pied by the sulfur atom and the nitrogen atom of a
neighboring molecule, respectively. The sum of equato-
rial angles are 359.4ꢁ (C(10)#1–Sn(1)–C(10) (123.4(5)ꢁ),
C(10)#1–Sn(1)–C(9) (118.0(3)ꢁ) and C(9)–Sn(1)–C(10)
(118.0(3)ꢁ)), in complex 1; 359.9ꢁ (C(25)–Sn(1)–C(21)
(118.7(5)ꢁ), C(25)–Sn(1)–C(17) (124.7(6)ꢁ) and C(21)–
Sn(1)–C(17) (116.5(5)ꢁ)), in complex 2; 358.04ꢁ
(C(23)–Sn(1)–C(9) (116.42(14)ꢁ), C(23)–Sn(1)–C(16)
(111.64(14)ꢁ) and C(9)–Sn(1)–C(16) (129.98(13)ꢁ)), in
complex 3; 359.86ꢁ (C(7)–Sn(1)–C(13) (122.50(14)ꢁ),
C(7)–Sn(1)–C(1) (121.21(12)ꢁ) and C(13)–Sn(1)–C(1)
(116.15(13)ꢁ)), in complex 4, respectively. They are all
Fig. 1. Molecular structure of the complex 1.

C.-L. Ma et al. / Polyhedron 24 (2005) 1773–1780
1777
Fig. 8. Perspective view showing the 1D polymeric chain of the
complex 4.
Fig. 5. Molecular structure of the complex 3.
Fig. 9. Molecular structure of the complex 5.
Fig. 6. Perspective view showing the 1D polymeric chain of the
complex 3.
Fig. 7. Molecular structure of the complex 4.
Fig. 10. Packing diagram of complex 5.
a little less than 360ꢁ, indicating that the corresponding
atoms are almost in the same plane. But the axial an-
gles are S(1)–Sn(1)–N(1)#2 (173.0(2)ꢁ) in complex 1;
N(1)–Sn(1)–S(2)#1 (177.49(15)ꢁ) in complex 2; N(1)–
Sn(1)–S(1)#1 (174.51(7)ꢁ) in complex 3; N(1)–Sn(1)–
S(1) (172.36(6)ꢁ) in complex 4, respectively, slightly

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C.-L. Ma et al. / Polyhedron 24 (2005) 1773–1780
Table 2
Table 4
˚
˚
Selected bond lengths (A) and bond angles (ꢁ) for complex 1
Selected bond lengths (A) and bond angles (ꢁ) for complex 3
Bond lengths
Sn(1)–C(10)
Sn(1)–S(1)
Bond lengths
Sn(1)–C(23)
Sn(1)–N(1)
Sn(1)–C(9)
2.125(9)
2.713(4)
2.13(1)
2.152(3)
2.455(3)
2.166(3)
2.657(1)
Sn(1)–C(9)
Sn(1)ꢁ ꢁ ꢁO(1)
Bond angles
3.278(9)
Sn(1)–S(1)#1
Bond angles
C(10)#1–Sn(1)–C(10)
C(9)–Sn(1)–S(1)
123.4(5)
C(23)–Sn(1)–C(9)
C(23)–Sn(1)–S(1)#1
C(23)–Sn(1)–C(16)
C(9)–Sn(1)–S(1)#1
C(9)–Sn(1)–C(16)
C(16)–Sn(1)–S(1)#1
C(23)–Sn(1)–N(1)
N(1)–Sn(1)–S(1)#1
C(9)–Sn(1)–N(1)
116.4(1)
91.0(4)
118.0(3)
173.0(2)
118.0(3)
70.3(3)
83.6(4)
70.3(3)
83.6(4)
143.0(4)
96.0(4)
121.0(3)
93.1(3)
52.0(1)
93.1(3)
91.01(9)
111.6(1)
99.3(1)
C(10)#1–Sn(1)–C(9)
N(1)#2–Sn(1)–S(1)
C(10)–Sn(1)–C(9)
C(10)#1–Sn(1)–O(1)
C(10)#1–Sn(1)–N(1)#2
C(10)–Sn(1)–O(1)
C(10)–Sn(1)–N(1)#2
C(9)–Sn(1)–O(1)
130.0(1)
92.8(1)
93.6(1)
174.51(7)
81.2(1)
98.2(1)
C(1)–S(1)–Sn(1)#2
C(16)–Sn(1)–N(1)
C(9)–Sn(1)–N(1)#2
N(1)#2–Sn(1)–O(1)
C(10)#1–Sn(1)–S(1)
S(1)–Sn(1)–O(1)
82.8(1)
Table 5
˚
Selected bond lengths (A) and bond angles (ꢁ) for complex 4
C(10)–Sn(1)–S(1)
Bond lengths
Sn(1)–C(7)
Sn(1)–N(1)
Sn(1)–C(13)
Sn(1)–S(1)
Sn(1)–C(1)
2.160(3)
2.524(2)
2.163(3)
2.8108(8)
2.173(3)
Table 3
˚
Selected bond lengths (A) and bond angles (ꢁ) for complex 2
Bond angles
Bond lengths
Sn(1)–C(25)
Sn(2)–C(37)
Sn(1)–C(21)
Sn(2)–N(3)
Sn(1)–C(17)
Sn(2)–S(1)
C(7)–Sn(1)–C(13)
C(7)–Sn(1)–S(1)
C(7)–Sn(1)–C(1)
C(13)–Sn(1)–S(1)
C(13)–Sn(1)–C(1)
C(1)–Sn(1)–S(1)
C(7)–Sn(1)–N(1)
N(1)–Sn(1)–S(1)
C(13)–Sn(1)–N(1)
C(1)–Sn(1)–N(1)
122.5(1)
2.11(1)
2.144(7)
2.11(1)
96.1(1)
121.2(1)
92.1(1)
2.440(6)
2.17(1)
116.2(1)
85.19(8)
84.8(1)
2.773(3)
2.415(6)
3.461(3)
2.765(3)
3.310(3)
2.131(6)
3.389(3)
2.140(7)
Sn(1)–N(1)
Sn(2)ꢁ ꢁ ꢁO(1)#1
Sn(1)–S(2)#1
Sn(1)ꢁ ꢁ ꢁN(2)
Sn(2)–C(33)
Sn(2)ꢁ ꢁ ꢁN(4)
Sn(2)–C(29)
172.36(6)
93.9(1)
87.85(9)
Table 6
˚
Selected bond lengths (A) and bond angles (ꢁ) for complex 5
Bond angles
Bond lengths
Sn(1)–C(21)
Sn(1)–S(1)
Sn(1)–C(9)
Sn(1)ꢁ ꢁ ꢁN(1)
Sn(1)–C(15)
S(1)–C(1)
C(25)–Sn(1)–C(21)
C(33)–Sn(2)–C(29)
C(25)–Sn(1)–C(17)
C(33)–Sn(2)–C(37)
C(21)–Sn(1)–C(17)
C(29)–Sn(2)–C(37)
C(25)–Sn(1)–N(1)
C(33)–Sn(2)–N(3)
C(21)–Sn(1)–N(1)
C(29)–Sn(2)–N(3)
C(17)–Sn(1)–N(1)
C(37)–Sn(2)–N(3)
C(25)–Sn(1)–S(2)#1
C(33)–Sn(2)–S(1)
C(21)–Sn(1)–S(2)#1
C(29)–Sn(2)–S(1)
C(17)–Sn(1)–S(2)#1
C(37)–Sn(2)–S(1)
N(1)–Sn(1)–S(2)#1
N(3)–Sn(2)–S(1)
118.7(5)
121.4(3)
2.105(9)
2.476(8)
2.12(1)
2.90(1)
2.14(1)
1.71(1)
124.7(6)
118.0(3)
116.5(5)
120.4(3)
88.4(3)
85.8(2)
90.9(3)
91.7(3)
88.5(3)
87.9(3)
89.6(3)
93.1(2)
91.4(3)
93.5(2)
91.5(3)
87.8(2)
177.5(2)
174.4(1)
Bond angles
C(21)–Sn(1)–C(9)
C(21)–Sn(1)–N(1)
C(21)–Sn(1)–C(15)
C(9)–Sn(1)–N(1)
C(9)–Sn(1)–C(15)
C(15)–Sn(1)–N(1)
C(21)–Sn(1)–S(1)
S(1)–Sn(1)–N(1)
C(9)–Sn(1)–S(1)
C(1)–N(1)–Sn(1)–
C(15)–Sn(1)–S(1)
N(2)–N(1)–Sn(1)
120.9(4)
78.5(3)
108.2(3)
82.8(3)
109.6(3)
157.9(3)
107.3(3)
59.2(2)
109.7(2)
83.3(6)
98.9(2)
169.2(6)

C.-L. Ma et al. / Polyhedron 24 (2005) 1773–1780
1779
˚
S atoms (4.00 A) [20]. And it is similar to that found
˚
in Ph3Sn[S(C7H5N4O)] (2.4760(17) A) [9] and Ph3Sn(S–
deviating from 180ꢁ, thus they are all distorted trigo-
nal–bipyramidal geometry.
˚
All the Sn–S bond lengths Sn(1)–S(1)#1 (2.713(4) A)
˚
C2SN2–S)SnPh3 (2.467(2) A) [8]. Besides, there exist
˚
for complex 1; Sn(1)–S(2)#1 (2.765(3) A) for complex 2;
˚
Sn(1)–S(1)#1 (2.6565(11) A) for complex 3; Sn(1)–S(1)
˚
(2.8108(8) A) for complex 4, are a little longer than the
˚
covalent radii of Sn and S (2.42 A) [18,19], and quite
shorter than the van der Waals radii of of Sn and S
intramolecular Snꢁ ꢁ ꢁN weak interaction, common ob-
served in triphenyltin heteroarenethiolates [25]. The
˚
Snꢁ ꢁ ꢁN bond length (2.896(12) A) is midway between
the sums of the covalent radii and van der Waals radii
˚
of tin and nitrogen (2.15–3.74 A) [21a] and can be re-
˚
(4.00 A) [20]. Concerning Sn–N bond lengths, the values
˚
are Sn(1)–N(1)#2 (2.450(12) A) for complex 1; Sn(1)–
˚
N(1) (2.415(6) A) for complex 2; Sn(1)–N(1)
garded as weak coordination bond. Including the
Snꢁ ꢁ ꢁN weak interaction, the geometry at tin in complex
5 becomes distorted cis-trigonal–bipyramidal with the
axial-tin-axial angle C(15)–Sn(1)–N(1) (157.9(3)ꢁ). As a
result of the Snꢁ ꢁ ꢁN weak coordination bond, though
the C–Sn–C bond angles are close to the theoretical tet-
rahedral angle, the C–Sn–S bond angles are more acute
or obtuse than it, largest deviations occurring in C(9)–
Sn(1)–S(1) 109.7(2)ꢁ, C(15)–Sn(1)–S(1) 98.9(2)ꢁ and
C(21)–Sn(1)–S(1) 107.3(3)ꢁ. In the oxadiazole, the C–S
˚
˚
(2.455(3) A) for complex 3; Sn(1)–N(1) (2.524(2) A) for
complex 4, respectively. All these lie in the range re-
corded in the Cambridge Crystallographic Database
˚
from 2.27 to 2.58 A [21b], slightly greater than the
sum of the covalent radii of tin and nitrogen atoms
˚
(2.15 A) but considerably less than the van der Waals ra-
˚
dii of the two atoms (3.74 A) [21a].
The intramolecular interaction distances of Sn,
˚
bond distance (C(1)–S(1) 1.708(11) A) lies between the
˚
N(2)#1 and/or Sn, O(1)#1 are: 3.158 and 3.278(9) A
˚
for complex 1; 3.310 and 3.583 A for complex 2; 3.206
average value of the double C@S bond in thioureas
˚
(1.681 A) and the single C–S bond in the C–S–Me frag-
˚
and 3.127 A for complex 3; 3.397 A for complex 4,
˚
˚
ment (1.789 A) [26], suggesting that the C–S bond has
respectively. All the bond distances are within the van
˚
der Waals radii of Sn and N atoms (3.74 A) [21a] and
some double-bond character in the deprotonated
oxadiazole.
˚
Sn and O atoms (3.68 A) [22a]. But they are much longer
than the values recorded in the Cambridge Crystallo-
˚
graphic Database (Sn–N 2.27–2.58 A) [21b] and Sn–O
4. Conclusions
˚
(2.61–3.02 A) [22b,c], and cannot be regarded as weak
coordination bonds.
Further, most Sn–S and Sn–N bond lengths in com-
plexes 1–4 are comparable with those in organotin(IV)
derivatives from heterocyclic thionates containing a
nitrogen atom (or more), such as organotin thiotetraz-
A series of organotin(IV) complexes based on 5-phe-
nyl-1,3,4-oxadiazole-2-thiol have been synthesized and
characterized. Detailed studies on the structures and
spectra of these complexes indicate that the stereo-con-
straints from the R groups of trialkyltin chloride have
great influence on the final coordination mode and crys-
tal structures. Methyl, n-butyl, benzyl, cyclohexyl have
the smaller spatial resistance, consequently, complexes
1–4 adopt the same coordination modes and exhibit
1D polymeric chains through Sn and N intermolecular
interactions, respectively. But, phenyl has the bigger ste-
reo-constraints and prevents another ligand chelating
the central tin atom, so, complex 5 does not form a
1D polymeric chain. Therefore, we conclude that the de-
crease of stereo-constraints may benefit the coordination
of nitrogen atoms.
˚
oles complexes (Sn–S 2.477(4)–2.614(5) A and Sn–N
˚
2.464(5)–2.810(7) A) [6,10a]. To some extent, our li-
gand has some resemblance with thiotetrazoles. Due
to the multidentate nature of the oxadiazole and tetra-
zole ring, both of them have the possibility to act as a
fulcrum through which lattice construction is orches-
trated in one or more dimensions [23]. And polymeric
chains of complexes 1–4 in this paper are covalently
linked through intermolecular Sn–N bonds, while
organotin thiotetrazoles complexes prefer to adopt
both covalent bond and all kinds of hydrogen bonding
to construct polymeric chain, 2D zigzag sheets and 3D
arrays [24].
5. Supplementary material
3.4.2. Ph3Sn[S(C8H5N2O)] (5)
For complex 5, the central tin atom forms four pri-
mary bonds: three to the phenyl groups and one to the
˚
sulfur atom. The Sn–S bond length (2.476(8) A) lies to-
ward the middle of the range reported for triphenyltin
˚
heteoarenethiolates (2.405–2.481 A) [18,19]. This bond
length is a little longer than the sum of covalent radii
˚
of Sn and S atoms (2.42 A) [18,19], but is considerably
shorter than the sum of van der Waals radii of Sn and
Crystallographic data (excluding structure factors)
for the structure reported in this paper have been
deposited with the Cambridge Crystallographic Data
Center as supplementary publication nos. CCDC-
257756 for 1, 238959 for 2, 257755 for 3, 261920 for
4 and 238958 for 5. Copies of the data can be ob-
tained free of charge on application to the Director,
CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK,

1780
C.-L. Ma et al. / Polyhedron 24 (2005) 1773–1780
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fax: +44 1223 336033, e-mail: deposit@ccdc.cam.ac.uk
or http://www.ccdc.cam.ac.uk.
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27 (1971) 969.
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(2003) 623.
We thank the National Natural Science Foundation
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