Syntheses and spectra of triphenyltin heteroarenethiolates: Crystal structures of triphenyltin 1-methyltetrazole-5-thiolate and triphenyltin benzoxazole-2-thiolate

Article abstract of DOI:10.1016/S0277-5387(99)00211-9

Reactions between Ph₃SnCl and the sodium salts of 5-mercapto-1-methyltetrazole (MTS-H), 2-mercaptobenzoxazole (MBZ-H), 2-mercaptobenzothiazole (MBT-H) and 2-mercapto-1-methylimidazole (MMI-H) gave Ph₃Sn(MTS) (5: R=Ph, R′=Me), Ph₃Sn(MBZ) 6, Ph₃Sn(MBT) 7 and Ph₃Sn(MMI) 8, respectively. Characterisation has been carried out for all compounds by IR, Moessbauer, ¹H, ¹³C and ¹¹⁹Sn NMR spectroscopy as well as by X-ray crystallography for (5: R=Ph, R′=Me) and 6. Both (5: R=Ph, R′=Me) and 6, in the solid state, have cis-trigonal bipyramidal geometries due to intramolecular Sn-N(2) interactions. Moessbauer data for 7 was interpreted as indicating a similar cis-trigonal bipyramid geometry. The chelating ability of nitrogen-containing heteroarenethiolato groups, based on the strength of Sn-N inter-molecular bonds in Ph₃SnS-heteroarenes, decreases in the sequence: pyridine-2-thiolato>pyrimidine-2-thiolato>1-methylimidazole-2- thiolato>benzoxazole-2-thiolato>1-methyltetrazole-5-thiolato>1- phenyltetrazole-5-thiolato. On dissolution, the Sn-N interactions in 5-8 undergo at least partial breakage. Elsevier Science Ltd.

Full text of DOI:10.1016/S0277-5387(99)00211-9

Polyhedron 18 (1999) 2961–2969
www.elsevier.nl/locate/poly
Syntheses and spectra of triphenyltin heteroarenethiolates
Crystal structures of triphenyltin 1-methyltetrazole-5-thiolate and
triphenyltin benzoxazole-2-thiolate
Carla V. Rodarte de Mouraa, Ana P.G. de Sousaa, Rosalice M. Silvaa , , Anuar Abras ,
b
*
c
c
d
e
¨
Manfredo Horner , Adailton J. Bortoluzzi , Carlos A.L. Filgueiras , James L. Wardell
aDepartamento de Quimica, Universidade Federal de Minas Gerais, 31270-901, Belo Horizonte, MG, Brazil
bDepartamento de Fisica, Universidade Federal de Minas Gerais, 31270-901, Belo Horizonte, MG, Brazil
cDepartamento de Quimica, Universidade de Santa Maria, 97119-000, Santa Maria, RS, Brazil
dInstituto de Quimica, Departamento de Quimica, Universidade Federal do Rio de Janeiro, C.P. 68563, 21945-970, Rio de Janeiro, RJ, Brazil
eDepartment of Chemistry, University of Aberdeen, Meston Walk, Old Aberdeen AB24 3UE, UK
Received 15 February 1999; accepted 22 June 1999
Abstract
Reactions between Ph3SnCl and the sodium salts of 5-mercapto-1-methyltetrazole (MTS-H), 2-mercaptobenzoxazole (MBZ-H),
2-mercaptobenzothiazole (MBT-H) and 2-mercapto-1-methylimidazole (MMI-H) gave Ph3Sn(MTS) (5: R5Ph, R95Me), Ph3Sn(MBZ)
1
6, Ph3Sn(MBT) 7 and Ph3Sn(MMI) 8, respectively. Characterisation has been carried out for all compounds by IR, Mossbauer, H, 13C
¨
and 119Sn NMR spectroscopy as well as by X-ray crystallography for (5: R5Ph, R95Me) and 6. Both (5: R5Ph, R95Me) and 6, in the
¨
solid state, have cis-trigonal bipyramidal geometries due to intramolecular Sn–N(2) interactions. Mossbauer data for 7 was interpreted as
indicating a similar cis-trigonal bipyramid geometry. The chelating ability of nitrogen-containing heteroarenethiolato groups, based on the
strength of Sn–N inter-molecular bonds in Ph3SnS-heteroarenes, decreases in the sequence: pyridine-2-thiolato.pyrimidine-2-thiolato.1-
methylimidazole-2-thiolato.benzoxazole-2-thiolato.1-methyltetrazole-5-thiolato.1-phenyltetrazole-5-thiolato. On dissolution, the Sn–N
interactions in 5–8 undergo at least partial breakage.
1999 Elsevier Science Ltd. All rights reserved.
¨
Keywords: X-ray crystallography; Triorganotin thiolates; Chelates; Mossbauer; Organotin compounds
1. Introduction
ple triorganotin thiolates, R3SnSR9, i.e. compounds in
which the R9 groups contain no donor centres, are in-
variably 4-coordinate compounds, with essentially tetra-
hedral structures: examples of such compounds are
Ph3SnSPh [8] and Ph3SnSMe [9]. However, if the R9
group does contain a donor centre [N or O], the coordina-
tion number at tin can increase, usually to five but also to
six. As shown by triorganotin heteroarenethiolates, the
higher coordination number can arise either via in-
tramolecular coordination of the tin centre with the donor
atom, e.g., as in 1 [10], 2 [11], 3 [12], 4 [13] and (5:
R5R95Ph) [14], or intermolecularly as in triphenyl(4-
pyridinethiolato)stannane [15] or by both intra- and inter-
molecular interactions as in (5: R5Me or PhCH2, R95Ph)
[16]. The geometry of the tin centre in the 5-coordinate
triorganotin thiolates is usually distorted trigonal bipyrami-
dal, as found in 1, 3, 4 and (5: R5Ph, R95Ph): however,
The coordination chemistry of tin is extensive with
various geometries and coordination numbers known for
both inorganic and organometallic compounds [1]. Higher
coordination numbers can be generated either by inter-
and/or intra-molecular interactions, especially in com-
pounds where tin bonds to electronegative atoms, such as
oxygen, nitrogen and sulfur. While tin is generally classi-
fied as a hard acid, many organotin–sulfur bonded com-
pounds are known. Solid state structures of several tri-
organotin thiolates, R3SnSR9, have been reported and are
listed in the Cambridge Crystallographic Data Base. Sim-
*Corresponding author. Tel.: 155-31-499-5734; fax: 155-31-499-
5700.
E-mail address: rosalice@apob.qui.ufmg.br (R.M. Silva)
0277-5387/99/$ – see front matter
PII: S0277-5387(99)00211-9
1999 Elsevier Science Ltd. All rights reserved.

2962
C.V. Rodarte de Moura et al. / Polyhedron 18 (1999) 2961–2969
in one case, 2, a square pyramidal geometry was reported
[11]. Six-coordinate compounds, (5: R5Me or PhCH2,
R95Ph), were described as having capped trigonal
bipyramidal structures [16].
2. Experimental
2.1. Materials and methods
All operations were carried out under nitrogen using
Schlenk and vacuum techniques. Nitrogen was dried over
molecular sieves. Hexane, tetrahydrofuran and toluene
were distilled over sodium/benzophenone. Acetone was
distilled and stored under nitrogen over molecule sieves.
Triphenyltin chloride and sodium 1-methyltetrazole-5-
thiolate (MTS-Na), 2-mercaptobenzothiazole (MBT-H)
from Aldrich, and 2-mercaptobenzoxazole (MBZ-H), from
Merck, and 2-mercapto-1-methylimidazole (MMI-H), from
Fluka, were used as supplied.
119
¨
Sn Mossbauer spectra were recorded with the sample
at liquid nitrogen temperature and a constant accelerated
CaSnO3 source, maintained at room temperature. All
¨
Mossbauer spectra were computer-fitted, assuming Lorent-
zian line-shapes. Infra-red spectra in the 4000–200 cm21
region were recorded on a Perkin-Elmer 283 spectrometer
in CsI plates. 1H, 13C and 119Sn NMR spectra were
recorded on Brucker AC-200 and AC-400 instruments and
were referenced to SiMe4 (for H and C) and SnMe4 (for
Sn). C, H, N analyses were performed using a Perkin-
Elmer PE-2400 CHN Micro-analyser. Tin analyses were
carried out using a Hitachi Z-8200 Polarized Zeeman
Atomic Absorption Spectrophotometer.
2.2. Syntheses
2.2.1. Sodium benzoxazole-2-thiolate (MBZ-Na)
A mixture of 2-mercaptobenzoxazole (MBZ-H) (0.30 g,
2.00 mmol) and CH3ONa (0.11 g, 2.00 mmol) in THF (40
ml) in a Schlenk flask was stirred at room temperature for
4 h. The white precipitate of MBZ-Na was collected,
washed three times with THF and dried. The IR spectrum
indicated the absence of the n(S–H) absorption band at
2500 cm21 [20]. Sodium benzothioxazole-2-thiolate
(MBT-Na) and sodium 1-methylimidazole-2-thiolate
(MMI-Na) were prepared similarly.
The intramolecularly coordinated species 1 (as also does 2)
contains a 5-membered chelate ring, which has been shown
by NMR spectroscopy to persist on dissolution [18]. Four-
membered chelate rings, as in 3, 4 and (5: R5R95Ph),
being more strained, are generally less stable than the
5-membered rings and may not persist in solution.
We have investigated the structures of four triphenyltin
heteroarenethiolate derivatives, (5: R5Ph, R95Me), 6–8
in the solid state, as well as in solution, and have compared
our data with those for similar triphenyltin thiolates in the
literature. To obtain a good comparison of the chelating
abilities of heteroarenethiolato groups (SArHET), which
form 4-membered chelate rings in R3SnSArHET com-
pounds, really requires the R groups to be the same
2.2.2. Triphenyltin benzoxazole-2-thiolate (Ph3SnMBZ), 6
A reaction mixture of MBZ-Na (0.45 g, 2.59 mmol) and
Ph3SnCl (1.00 g, 2.59 mmol) in THF (80 ml) in a Schlenk
flask was refluxed for 4 h, cooled to room temperature and
filtered through celite. The solvent from the filtrate was
evaporated under vacuum. The yellow-oily residue was
washed three times with hexane/acetone (1:1): the title
compound was crystallised from CH2Cl2 /hexane and was
obtained as a pale yellow solid, yield 85%, m.p. 83.3–
86.28C. Found: C, 59.3; H, 3.7; N, 2.9; Sn, 24.6.
C25H19NOSSn requires: C, 60.0; H, 3.7; N, 2.7; Sn,
23.7%. 1H NMR (CDCl3): d: 7.11–7.48 (m, C6H4), 7.60–
7.89 (m, C6H5). 13C NMR (CDCl3): d: 109.6–152.6 (aryl-
¨
throughout the series being compared. The Mossbauer and
NMR solution spectra of (5: R5Ph, R95Me), 6–8 have
been determined as have the crystal structures of (5:
R5Ph, R95Me) and 6. The crystal structure of 8 was
published during the course of our investigation [19];
unfortunately suitable crystals of 9 could not be obtained
for an X-ray study.

C.V. Rodarte de Moura et al. / Polyhedron 18 (1999) 2961–2969
2963
C), 165.0 (C=N). 119Sn NMR (CDCl3): d: 278.9.
2112.9 at ambient temperature; lit. value 2112.2 [18].
¨
¨
Mossbauer spectrum (mm/s): d51.3460.01; D5
Mossbauer spectrum (mm/s): d51.2860.01; D5
2.0360.02. IR (CsI, cm21): n(C=N) 1705, n(Sn–S) 290.
2.9860.01. IR (CsI, cm21): n(Sn–S) 290.
2.3. Crystal structure determination
2.2.3. Triphenyltin benzothioxazole-2-thiolate
(Ph3SnMBT), 7
Colorless crystals of (5: R5Ph, R95Me) and 6 were
mounted on a glass fiber and used for intensity data
collection. The unit cell dimensions and the orientation
matrix for the data collection for both compounds, resulted
from a least square fit of 25 reflections. The automatic
intensity search and indexing method indicated a cell
belonging to an monoclinic crystal system with a C lattice
(for 6) and belonging to a monoclinic crystal system with a
P lattice [for (5: R5Ph, R95Me)]. X-ray intensity data
were collected on an Enraf-Nonius CAD-4 diffractometer
A reaction mixture of MBT-Na (0.47 g, 2.46 mmol) and
Ph3SnCl (0.94 g, 2.46 mmol) in THF (80 ml) in a Schlenk
flask was refluxed for 2 h, cooled to room temperature and
evaporated under vacuum. The yellow-oily solid residue
was washed with hexane (6320 ml) and was crystallised
from CH2Cl2 /hexane as a pale yellow solid, yield 83%,
m.p. 88.8–90.48C (lit. value 89–908 [21]). Found: C, 57.4;
H, 3.7; N, 2.7; Sn, 22.8. C25H19NS2Sn requires: C, 58.2;
H, 3.7; N, 2.7; Sn, 23.0%. 1H NMR (CDCl3): d: 7.24–7.89
(m, C6H5). 13C NMR (CDCl3): d: 122.2–137.6 (aryl-C),
139.9 (C=N). 119Sn NMR (CDCl3): d: 291.4. Mossbauer
˚
using Mo Ka radiation (l50.71073 A) and a graphite
¨
monochromator [22], employing v–2u scans with a scan
speed of 30 s/reflection. Every 60 min, the intensity and
orientation of the standard reflections were measured; the
observed intensity decay was less than 0.6% over the data
collection. From the Bravais lattice and observed reflection
conditions, the space group was chosen to be Cc for 6 and
P2(1)/c for (5: R5Ph, R95Me). Lorentz and polarization
corrections were made on the intensity data. Despite the
low linear absorption coefficients observed [(1.248 (6) and
1.394 mm21 (5: R5Ph, R95Me)], a semi-empirical
absorption correction based on psi-scans were performed
on intensity data [22].
The structures were solved using the direct methods
employing SHELXS-86 program [23] and all non-hydro-
gen atoms were located by subsequent Fourier difference
synthesis. For structure refinement the SHELXL-97 pro-
gram [24] was employed and the full-matrix least-squares
method minimized on o w(F2o 2 Fc2)2 where w is a
weighting scheme detailed below. All non-hydrogen atoms
were refined using anisotropic thermal parameters. All the
hydrogen atoms were obtained geometrically and their
displacement parameters were refined isotropically on a
groupwise basis. For the final refinement of the structure
an isotropic extinction correction was included. Scattering
factors for all atoms were as in the SHELXL-97 program
[24]. The final refinements including 263 parameters gave
R1 52.29% and wR2 56.10% with the weighting scheme,
w 5 1/[s2(Fo2) 1 (0.0327P)2 1 6.8036P] where P 5 (F2o 1
2F2c )/3 with a maximal shift/e.s.d.51.684 for 6 and
including 236 parameters gave R1 52.05% and wR2 5
5.12% with the weighting scheme, w 5 1/[s2(Fo2) 1
(0.0209P)2 1 0.6416P] where P 5 (Fo2 1 2Fc2)/3 with a
maximal shift/e.s.d.50.311 for (5: R5Ph, R95Me).
Table 1 summarizes the crystal data and structure refine-
ment parameters for 6 and (5: R5Ph, R95Me). The
ZORTEP package was used for the molecular drawings
[25].
spectrum (mm/s): d51.3260.01; D51.7960.01. IR (CsI,
cm21): n(Sn–S) 290.
2.2.4. Triphenyltin 1-methyltetrazole-5-thiolate
(Ph3SnMTS), (5: R5Ph, R95Me)
A reaction mixture of MTS-Na (0.36 g, 2.59 mmol) and
Ph3SnCl (1.00 g, 2.59 mmol) in THF (80 ml) in a Schlenk
flask was refluxed for 4 h, cooled to room temperature and
concentrated under vacuum. The yellow-oily solid residue
was extracted with hexane (3320 ml) and the combined
hexane extracts were evaporated to leave an oily residue,
which was crystallised from acetone/hexane as a white
solid, yield 88%, m.p. 88.5–90.18. Found: C, 52.2, H, 3.9,
N, 11.7, Sn, 23.7. C20H18N4SSn requires C, 51.7, H, 3.9,
N, 12.0, Sn, 24.6%. 1H NMR (CDCl3): d: 3.82 (s, CH3),
7.02–7.96 (m, C6H5). 13C NMR (CDCl3): d: 33.8 (CH3),
129.5–142.9 (aryl-C), 153.6 (C=N). 119Sn NMR (CDCl3):
¨
d: 270.9. Mossbauer spectrum (mm/s): d51.3660.01;
D52.4860.01. IR (CsI, cm21): n(Sn–S) 310.
2.2.5. Triphenyltin 1-methylimidazole-2-thiolate
(Ph3SnMMI), 8
A reaction mixture of MMI-Na (0.36 g, 2.59 mmol) and
Ph3SnCl (1.00 g, 2.59 mmol) in THF (50 ml) in a Schlenk
flask was refluxed for 16 h, cooled to room temperature
and evaporated under vacuum. The yellow-oily solid
residue was filtered through a Sephadex column and was
eluted with methanol. Triphenyltin 1-methylimidazole-2-
thiolate was obtained as a white solid, yield 83%, m.p.
73.9–76.78C. Found: C, 56.62; H, 4.38; N, 6.32; Sn, 26.3.
C22H20N2SSn requires: C, 57.1; H, 4.40; N, 6.00; Sn,
25.6%. 1H NMR (CDCl3): d: 3.43 (s, CH3), 6.77 (d, CH),
6.90 (d, CH), 7.31–7.75 (m, C6H5). 13C NMR (CDCl3): d:
33.4 (CH=), 119.7 (CH), 128.3 (CH), 128.7–137.1 (aryl-
C), 138.5 (C=N). 119Sn NMR (CDCl3): d: 257.7 and

2964
C.V. Rodarte de Moura et al. / Polyhedron 18 (1999) 2961–2969
Table 1
Crystal data and structure refinement
Compound
6
(5: R5Ph, R95Me)
Empirical formula
Formula weight
Temperature (K)
Wavelength (l)
Crystal system
Space group
C25
H
19NOSSn
C20H18N4SSn
465.13
293(2)
0.71073
Monoclinic
P21 /c
500.16
293(2)
0.71073
Monoclinic
Cc
Unit cell dimensions
˚
a (A)
8.629(2)
38.534(8)
6.856(1)
9.584(2)
21.854(4)
9.603(3)
˚
b (A)
˚
c (A)
b (8)
Volume (A )
100.62(3)
2240.6(8)
96.80(3)
1997.2(7)
3
˚
Z
4
4
Density (calc.) (Mg/m3)
1.483
1.248
1.547
1.394
Absorption coefficient (mm21
)
Max/min transmission factors
F(000)
0.96289/0.91237
1000
0.98848/0.91828
928
Crystal size (mm)
0.1630.3030.47
0.4730.4030.36
Theta range for data collection (8)
Index ranges
2.88 to 25.15
210#h#10
2.33 to 25.28
211#h#11
246#k#0
0#k#26
0#l#8
211#l#0
Reflections collected
Independent reflections
Observed reflections [I.2s(I)]
R(int)
Refinement method
Number of parameters
Goodness-of-fit on F2
Final R indices [I.2s(I)]
R indices all data
2189
2181
2181
0.0181
3860
3631
3631
0.0122
Full-matrix l.s. on F2
263
Full-matrix l.s. on F2
236
1.043
1.097
R150.0229, wR250.0610
R150.0334, wR250.0734
w5l/[s2(F2o)1(0.0327P)216.8036P]
where P5(F2o 12Fc2)/3
0.01(4)
R150.0205, wR250.0512
R150.0309, wR250.0545
w51/[s2(F2o)1(0.0209P)10.6416P]
where P5(F2o 12Fc2)/3
Final weighting scheme
Absolute structure parameter
Residual diffraction max/min (e/A3)
0.529/ 20.836
0.322/ 20.221
3. Results and discussion
3.1. Synthesis
Compounds were prepared by reaction of the sodium
thiolate with Ph3SnCl. All were crystalline solids. Com-
pound 8 was particularly sensitive to hydrolysis to give
Ph3SnOH [d 119Sn5289.8 ppm] in solution, as found
previously [19].
3.2. Crystal structures of (5: R5Ph, R95Me) and 6
Atom arrangements and numbering systems for (5: R5
Ph, R95Me) and 6 are shown in Figs. 1 and 2. Selected
bond distances, bond angles and torsion angles are listed in
Tables 2 and 3.
The four primary bonds to Sn in 6 are to the three
˚
phenyl groups [Sn–C between 2.118(7) and 2.145(7) A]
˚
and to S [Sn–S52.458(2) A], in addition there is a weak
˚
intramolecular Sn–N interaction [Sn–N(2)53.070(6) A],
Fig. 1. Atom arrangements and numbering system for (5; R5Ph, R95
thus providing a 4-membered chelate ring with a bite
Me). Probability ellipsoids drawn at 30%.

C.V. Rodarte de Moura et al. / Polyhedron 18 (1999) 2961–2969
2965
˚
tween 2.131(2) and 2.139(2) A, Sn(1)–S(1)52.4708(8)
˚
and Sn(1)–(N2)53.161(3) A. The axial–Sn–axial angle,
[C(21)–Sn(1)–N(2)], is 153.5(8)8 with a chelate bite angle
˚
of 56.61(6)8. The Sn(1) atom is displaced by 0.630(1) A
from the geometric centre of the equatorial plane of C(11),
C(31) and 5(1). None of the other nitrogen atoms, N(1),
N(3) and N(4) interact with tin centres. Molecule (5: R Ph,
R95Me), thus, has a similar structure to compound (5:
R5Ph, R95Ph) [14] in existing as discrete distorted
trigonal bipyramidal molecules, in contrast to capped
trigonal bipyramidal (5: R5Me or PhCH2, R95Ph) [16]:
additional inter-molecular Sn–N interactions result in (5:
R5Me, R95Ph) existing as a cyclic trimer and (5: R5
PhCH2, R95Ph) as a linear polymer. The differences in
these structures result more from differences in the steric
demands of the R groups than from differences in their
electronic effects.
Fig. 2. Atom arrangements and numbering system for 6. Probability
ellipsoids drawn at 30%.
angle, N(2)–Sn–S(1), of 57.3(1)8. The Sn–S bond length
in 6 is slightly outside the range [2.39–2.44 A] found in
3.3. Comparison of the solid state structures of
triphenyltin heteroarenethiolates
˚
4-coordinate R3SnSR9 compounds [8]. The Sn–N(2) dis-
tance is midway between the sums of the van der Waals
and covalent radii of Sn and N, 3.74 and 2.15 A,
The solid state structures of several triorganotin
heteroarenethiolates have now been determined by X-ray
crystallography. Table 4 provides structural details of
triphenylstannylthiolato derivatives of nitrogen-containing
heteroarenes, in which the thiolate group is ortho to a ring
nitrogen, as well as of 1. Although a structure determi-
nation of triphenyltin pyridine-2-thiolate (9, Ar5Ph) has
been attempted, disorder prevented an adequate solution
being obtained [12]: however structural details of the close
analogue, tri( p-tolyl)tin pyridine-2-thiolate, 3, are avail-
able [12]. As the influence of the R group on the structure
of a R3SnSR9 compound appears to be due more to steric
than electronic effects, the bond length data for tri( p-
tolyl)tin pyridine-2-thiolate is assumed to be similar to
˚
respectively [27]. Including the tin–nitrogen interaction,
the geometry at Sn becomes distorted cis-trigonal
bipyramidal with C(21) and N(2) in axial sites [C(21)–
Sn–N(2)5154.7(2)8]. The Sn atom is displaced by
˚
0.631(4) A from the geometric centre of the equatorial
plane of C(11), C(31) and S. The oxygen atom is not
involved in coordination to any tin centre. The observed
Flack parameter [28] 0.01(4), suggests that only one of the
enantiomeric pair of 6 is present in the unit cell.
Crystalline (5: R5Ph, R95Me) has a similar distorted
trigonal pyramidal geometry with a tin–nitrogen in-
tramolecular interaction with Sn–C bond lengths of be-
Table 2
˚
Selected bond lengths (A) and angles (8) for (5: R5Ph, R95Me) with e.s.d.’s in parenthesis
S(1)–C(1)
Sn(1)–C(31)
Sn(1)–C(21)
N(2)–C(1)
N(3)–N(4)
N(5)–C(1)
1.730(3)
2.131(2)
2. 139(2)
1.322(3)
1.288(4)
1.336(3)
S(1)–Sn(1)
Sn(1)–C(11)
Sn(1)–N(2)
N(2)–N(3)
N(4)–N(5)
N(5)–C(6)
2.4708(8)
2.134(2)
3. 161(3)
1.355(3)
1.340(3)
1.448(4)
C(1)–S(1)–Sn(1)
96.55(9)
110.24(9)
109.53(7)
96.99(7)
56.61(6)
153.5(1)
110.6(2)
107.9(2)
122.8(3)
127.1(2)
164.8(2)
82.5(3)
C(31)–Sn(1)–C(11)
C(11)–Sn(1)–C(21)
C(11)–Sn(1)–S(1)
C(1)–N(2)–N(3)
N(2)–Sn(1)–C(11)
N(2)–Sn(1)–C(31)
N(3)–N(4)–N(5)
C(1)–N(5)–C(6)
N(2)–C(1)–N(S)
N(5)–C(1)–S(1)
C(12)–C(11)–Sn(1)–S(1)
120.73(9)
C(31)–Sn(1)–C(21)
C(31)–Sn(1)–S(1)
C(21)–Sn(1)–S(1)
N(2)–Sn(1)–S(1)
N(2)–Sn(1)–C(2 1)
N(4)–N(3)–N(2)
C(1)–N(5)–N(4)
N(4)–N(5)–C(6)
N(2)–C(1)–S(1)
C(26)–C(21)–Sn(1)–S(1)
C(32)–C(31)–Sn(1)–S(1)
110.32(9)
106.33(7)
105.6(2)
82.34(9)
80.09(9)
107.2(2)
129.2(3)
108.7(2)
124.2(2)
95.6(2)

2966
C.V. Rodarte de Moura et al. / Polyhedron 18 (1999) 2961–2969
Table 3
˚
Selected bond lengths (A) and angles (8) for 6 with e.s.d.’s in parenthesis
Sn–C(11)
Sn–C(31)
Sn–N(2)
N(2)–C(1)
O(5)–C(1)
C(3)–C(4)
2.118(7)
2. 145(7)
3.070(8)
1.286(9)
1.368(9)
1.361(10)
Sn–C(21)
Sn–S
S–C(1)
N(2)–C(3)
O(5)–C(4)
C(3)–C(6)
2.131(7)
2.458(2)
1.724(8)
1.422(9)
1.379(9)
1.380(11)
C(11)–Sn–C(21)
C(21)–Sn–C(31)
C(21)–Sn–S
N(2)–Sn–S(1)
N(2)–Sn–C(21)
C(1)–S–Sn
C(1)–O(5)–C(4)
N(2)–C(1)–S
C(4)–C(3)–C(6)
C(6)–C(3)–N(2)
C(12)–C(11)–Sn–S
C(36)–C(31)–Sn–S
108.3(3)
C(11)–Sn–C(31)
C(11)–Sn–S
C(31)–Sn–S
N(2)–Sn–C(11)
N(2)–Sn–C(31)
C(1)–N(2)–C(3)
N(2)–C(1)–O(5)
O(5)–C(1)–S
118.2(3)
110.3(3)
98.4(2)
57.3(1)
154.8(3)
95.0(2)
103.3(5)
127.2(6)
121.7(7)
130.1(7)
35.6(7)
67.8(7)
108.8(2)
111.0(2)
76.8(2)
87.1(2)
103.8(6)
115.9(7)
116.9(5)
108.2(6)
59.7(7)
C(4)–C(3)–N(2)
C(26)–C(21)–Sn–S
those for triphenyltin pyridine-2-thiolate and hence are
included in Table 4.
suitable crystals of 7 could not be grown for X-ray
crystallographic study.
Compound 1 was reported to have a 5-membered
chelate ring, with Sn–S and Sn–N bond lengths of
The isomer shift value for 1, with the stronger Sn–N
interaction, was reported to be 1.20 mm/s [31], compared
to the range of 1.26 to 1.36 mm/s for the other
heteroarenethiolates, 4–9, with the weaker Sn–N interac-
tions, as well as for 4-coordinate Ph3SnSC6H4X-p [32].
The quadrupole splitting for 1 was reported to be 1.37
mm/s [31]: values for 4–9 are in the range from 1.60 (for
4) to 2.98 mm/s (for 8) and for Ph3SnSSC6H4X-p, which
are ca. 1.3–1.4 mm/s. An approximate range of quad-
rupole splitting values for cis-trigonal bipyramidal, [fac-
R3], R3SnX compounds is quoted as being 1.70–2.55
mm/s and overlaps both the ranges for tetrahedral [1.2–3.3
mm/s] and (eq-R3)-trigonal bipyramidal [2.4–4.2 mm/s]
R3SnX species [33]. However, there is no doubt from the
X-ray work that the solid triphenyltin heteroarenethiolates
are all cis-trigonal bipyramidal R3SnX compounds, albeit
with weak Sn–N interactions. There is no correlation
between the intramolecular Sn–N bond length and the
quadrupole splitting value.
˚
˚
2.441(3) and 2.427(3) A and 2.592(9) and 2.611(8) A,
respectively, in two independent molecules [10], see Table
4. Crystal structure determinations of all the other 5-
coordinate triphenyltin heteroararenethiolates listed in
Table 4 revealed intramolecular Sn–N interactions and
strained 4-membered chelate rings [12]. A comparison of
the donor abilities (chelating abilities) of the heteroaryl
units is readily available from the Sn–N intramolecular
bond lengths: the shorter the Sn–N separation, the stronger
the interaction. The Sn–N bond in 1, with the 5-membered
chelate ring, is shorter than in any of the 4-membered
chelates. The chelating ability sequence, based on the
Sn–N bond lengths, is: quinoline-8-thiolato.pyridine-2-
thiolato.pyrimidine-2-thiolato.1-methylimidazole-2-
thiolato.benzoxazole-2-thiolato.1-methyltetrazole-5-
thiolato.1-phenyltetrazole-5-thiolato. Two conclusions
from this comparison are (i) the 6-membered heteroaryl
species [pyridinyl and pyrimidinyl] provide stronger che-
lates than do the 5-membered species and (ii) weaker
donors are obtained on increasing substitution of carbon by
nitrogen atoms. The Sn–S bond in the 5-coordinate
triphenyltin heteroarenethiolates are all slightly longer than
Sn–S bonds in 4-coordinate R3SnSR9: however, there is no
obvious relationship between Sn–S and Sn–N bond
lengths in these 5-coordinate species.
¨
From the Mossbauer data, it is assumed that 7 also has a
cis-trigonal bipyramidal structure in the solid state.
3.5. Solution NMR data
The Sn–N intramolecular interaction in 1 remains intact
on dissolution in CHCl3 solution as shown by the similar
119Sn NMR chemical shift values in the solid state
[d 119Sn: 2147.0 and 2159.0 ppm] and in solution
[d 119Sn: 2147.0 ppm] [18]. In contrast, the Sn–N interac-
tions in (5: R5Ph, R95Me or Ph), and 6–8 are, at least,
partially broken in chlorocarbon solution. Sordo et al.
reported a single d 119Sn NMR value of 2112.2 ppm for 8
in CDCl3 solution [19]. We observed, in this study, two
¨
3.4. Mossbauer spectra
¨
Mossbauer spectra were obtained in this study for (5:
R5Ph, R95Me) and 6–8; details are included in Table 4
along with literature values for other compounds [13]. The
Mossbauer data for 7 are particularly valuable since
d
119Sn values at ambient temperature, 257.1 and 2112.9
¨

C.V. Rodarte de Moura et al. / Polyhedron 18 (1999) 2961–2969
2967
Table 4
Selected structural and spectral data for triphenyltin heteroarenethiolates
Compound
Solution
NMR
Solid state
¨
Mossbauer
X-ray
d
119Sn
IS
(mm/s)
QS
(mm/s)
d(Sn–S)
A
d(Sn–N)
A
Geometry
at tin
˚
˚
2150.5 (solution)
2147.0 &
2159.0 (solid state)
1.20
[28]
1.37
[28]
2.441(3) &
2.427(3)
[8]
2.592(9) &
2.611(8)
[8]
Distorted
cis-trigonal
bipyramidal
[15]
257.1a
2112.9a
2112.2
1.28a
2.98a
2.437
[16]
2.920(3)
Sn–N(2)
[16]
Distorted
cis-trigonal
bipyramidal
[16]
270.9a
1.36a
2.48a
2.4708(8)a
3.161(3)a
Sn–N(2)
Distorted
cis-trigonal
bipyramidal
Distorted
cis-trigonal
269.4
[26]
1.33
[26]
2.38
[26]
2.482(1)
[12]
3.275(3)
Sn–N(2)
[12]
bipyramidal
Distorted
278.9a
1.34a
2.03a
2.458(2)a
3.070(6)a
cis-trigonal
bipyramidal
291.4a
2116.3
Ar5Ph
[27]
1.32a
1.26
Ar5Ph
[27]
1.79a
1.62
Ar5Ph
[27]
2.455(7)
2.444(7)
Ar5C6H4Me-p
2.73(3)
2.74(3)
Ar5C6H4Me-p
Distorted
cis-trigonal
bipyramidal
[10]
[10]
1.31
[11]
1.65
[11]
2.442(3)
[11]
2.88(5)
[11]
Distorted
cis-trigonal
bipyramidal
Distorted
tetrahedral
Distorted
Ph3SnSPh
265.2(CH2Cl2)
[31]
265.8
1.33
[29]
1.31
[29]
1.41
[29]
1.34
[29]
2.421(1)
[6]
2.413
[23]
–
–
Ph3SnSC6H4But-p
[31]
tetrahedral
a This study.

2968
C.V. Rodarte de Moura et al. / Polyhedron 18 (1999) 2961–2969
´
ppm. The relative intensities of the two peaks varied with
temperature: lowering the temperature led to a reduction in
the relative intensity of the lower field value and at 240 K,
only the higher field peak (now at 2124.0 ppm) was
present. As the temperature effects are reversible, an
equilibrium between 4- and 5-coordinate species is as-
sumed, Eq. (1), which is slow on the NMR timescale. The
lower field peak (from 257.1 to 260 ppm) is associated
with a 4-coordinate species, by comparison with the values
[¯265 ppm] for 4-coordinate Ph3SnSC6H4X-p in chloro-
carbon solvents [34]. The higher field value of between
2112.9 and 2124.0 ppm is assigned to the 5-coordinate,
chelated species and is close to the d 119Sn value of
2116.3 ppm reported for triphenyltin pyridine-2-thiolate
(9: R5Ph) in chlorocarbon solution [29]. The difference
[ca. 30 ppm] in the solution d 119Sn NMR values for
5-coordinate 1, on one hand, and for 5-coordinate 8 and 9,
on the other, is considered to arise from the different
chelate ring sizes and the consequent differences in Sn–N
bond lengths.
(UFSC, Florianopolis, Brazil) for the diffractometer
facilities.
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