Synthesis and characterisation of phosphinothiolate tin(IV) complexes. Crystal structure of [SntBu2(OPPh2C6H 4S)(OH2)]ClO4·H2O

Article abstract of DOI:10.1016/S0277-5387(01)00897-X

[SnR₂Cl₂] (R=Me, ^tBu) react with OPPh₂C₆H₄SH in the presence of NaOEt affording mononuclear derivatives [SnR₂(OPPh₂C₆H₄S)₂] (1, 2) wit

Full text of DOI:10.1016/S0277-5387(01)00897-X

Polyhedron 20 (2001) 2863–2867
www.elsevier.com/locate/poly
Synthesis and characterisation of phosphinothiolate tin(IV)
complexes. Crystal structure of
[SntBu2(OPPh2C6H4S)(OH2)]ClO4·H2O
Elena Cerrada a, Mariano Laguna a,*, Mike B. Hursthouse b, Raquel Terroba a
a Departamento de Qu´ımica Inorga´nica, Instituto de Ciencia de Materiales de Arago´n, Uni6ersidad de Zaragoza-C.S.I.C,
E-50009 Zaragoza, Spain
b Department of Chemistry, Uni6ersity of Southampton, Highfield, Southampton, SO17 1BJ, UK
Received 17 May 2001; accepted 20 July 2001
Abstract
[SnR2Cl2] (R=Me, tBu) react with OPPh2C6H4SH in the presence of NaOEt affording mononuclear derivatives
[SnR2(OPPh2C6H4S)2] (1, 2) with two units of the oxide of the thiophenylphosphine. The loss of one of such units is achieved by
the reaction of 1 and 2 with HCF3SO3 or HClO4 giving rise to complexes with the formula [SnR2(OPPh2C6H4S)]A (A=CF3SO3,
ClO4) (3a–b, 4a–b). The crystal structure of [SntBu2(OPPh2C6H4S)]ClO4 (4b) has been determined by X-ray diffraction. © 2001
Published by Elsevier Science Ltd.
Keywords: Phosphinothiolate derivatives; Tin complexes; Phosphine oxide
acterisation of some tin(IV) complexes with the oxide
of the diphenylphosphinothiol: OPPh2(C6H4SH) and
their reactivity in the presence of a non-coordinative
acid. The crystal structure of [SntBu2(OPPh2C6H4S)]-
ClO4 is also reported.
1. Introduction
Metal thiolato complexes have been extensively stud-
ied because of their ability to adopt various nuclearities
and their relevance in biology, since they form the
inorganic part of the biologically active centres of some
metalloproteins and enzymes [1–3]. Recently, attention
has been paid to the coordination chemistry of
polydentate ligands that incorporate both thiolato and
tertiary phosphine donor sites, because they give poten-
tial access to new compounds with unusual structures
and reactivities [4]. In this regard, the most studied
systems are the proligands PR2C6H4SH and
PR2CH2CH2SH [5–14] and some examples with the
oxide of such phosphines, in particular the arene ones,
have been reported [15–20].
2. Results and discussion
The reaction of OPPh2(C6H4SH) with tin(IV) com-
plexes [SnR2Cl2] (R=Me, tBu) in the presence of
sodium ethoxide in a 1:2 ratio, affords complexes 1 and
2 with a similar formulation to that previously de-
scribed [13] with the phosphine PPh2(C6H4SH) (Scheme
1, process i).
Their IR spectra do not show the band associated
with n(SꢀH), which appears at 2495 cm−1 in the free
ligand. These spectra also show a band due to the
n(P.O) at about 1140 cm−1, displaced 40 cm−1 down
As a result of our continuing interest in the coordina-
tion of main group metals with arenephosphinothiolate
ligands [13,14], here we describe the synthesis and char-
1
from the value of the starting phosphine. In the H-
NMR spectra the signal due to the SꢀH group, centred
at 6.2 ppm in the free ligand, has disappeared, which
confirms the presence of the anionic form of the ligand.
In addition, the spectra show in both cases a singlet due
* Corresponding author. Tel.: +34-976-761181; fax: +34-976-
761187.
E-mail address: mlaguna@posta.unizar.es (M. Laguna).
0277-5387/01/$ - see front matter © 2001 Published by Elsevier Science Ltd.
PII: S0277-5387(01)00897-X

2864
E. Cerrada et al. / Polyhedron 20 (2001) 2863–2867
Scheme 1.
t
to the methyl and Bu radicals bonded to the tin centre
flanked by tin satellites. The 31P-NMR spectra display a
singlet centred at about 33 ppm, again flanked by tin
satellites and downfield displaced from the value of the
free ligand, due to the coordination of the tin centre.
The 119Sn-NMR spectra show a doublet at −90 (1)
and −97 (2) ppm as a consequence of the SnꢀP
coupling, with coupling constants of about 60 Hz. The
presence of such SnꢀP coupling in addition to the big
displacement of the n(P.O) in the IR spectra, suggests
a coordination of the oxygen atom of the phosphine to
the tin centre. This fact is also observed in complexes 3
and 4, described below, and confirmed by X-ray dif-
fraction in one of them. With this idea we can propose
an hexacoordinated structure for the tin(IV) (Scheme
1), where the two oxides of the phosphinethiolate are
mutually in cis. With such a disposition, two different
isomers can be described, with both oxygen mutually
trans or cis. We were not able to distinguish between
them without any crystallographic data, but in solution
only one of the isomers is present.
bonded to the metal showing the tin satellites. In the
case of 31P-NMR the singlets are down field displaced
from the values of the starting derivatives. The 119Sn-
NMR spectra also show a doublet in all cases, due to
the SnꢀP coupling. The mass spectra (LSISM+, nba as
matrix) show the parent peaks corresponding with the
cation formulation [M−X] + as the base peaks in all
cases. In addition, these complexes behave as 1:1 elec-
trolytes in acetone solutions [23].
The crystallisation of one of these complexes (4b)
afforded suitable crystals for X-ray studies that
analysed as [SntBu2(OPPh2C6H4S)(OH2)]ClO4, where
an extra OH2 molecule has been incorporated to the tin
coordination sphere, probably from the crystallisation
solvent. The molecular structure of its H2O solvate has
been determined and is shown in Fig. 1. Selected bond
lengths and angles are given in Table 1. The cation
consists of a pentacoordinated discrete molecular unit
in which one molecule of water (O(6)), is coordinated
to tin along with the oxidated phosphine (O(5)). The
coordination environment around the tin atom is a
distorted trigonal bipyramid, as in [SnCl5] − [24], with
both tert-butyl groups and the thiolate occupying the
The LSIMS+ (nba as matrix) mass spectra of these
compounds show a small intensity molecular peak. The
base peaks in both cases correspond to the loss of one
of the phosphine ligands.
Since these species seem to be the most stable in the
fragmentation process of 1 and 2, we tried to isolate
them by the reaction of complexes 1 and 2 with a
non-coordinative acid. Thus, the reaction of complexes
[SnR2(OPPh2C6H4S)2] (R=Me, tBu) with HA
(HCF3SO3 or HClO4) gave complexes [SnR2(OPPh2C6-
H4S)]A (R=Me, A=TfO 3a, ClO4 3b; R=tBu, A=
TfO 4a, ClO4 3b) as air-stable solids. The process can
be described as the protonation of one of the phosphine
ligands, giving rise to free OPPh2(C6H4SH) and the new
complexes. (Scheme 1, process ii).
The IR spectra of complexes 3a–b and 4a–b show
the vibration n(P.O) displaced a few cm−1 compared
with the starting derivatives 1 and 2. Additionally the
characteristic bands of the anionic triflate [21] and
perchlorate [22] appear respectively.
−
−
Independent of the anion CF3SO3 or ClO4 the
complexes show the same spectroscopic data. So the
1H-NMR spectra show, apart from the multiplets in the
phenyl region, a singlet due to the methyl or tBu groups
Fig. 1. Molecular structure of 4b showing the cation. Thermal
ellipsoids are drawn at the 50% probability level and H atoms have
been omitted for clarity.

E. Cerrada et al. / Polyhedron 20 (2001) 2863–2867
2865
Table 1
3.3. Preparation of [SnR2(OPPh2C6H4S)2] R=Me (1),
tBu (2)
,
Bond lengths [A] and angles [°] for 4b
Bond lengths
To a suspension of OPPh2C6H4SH in ethanol (0.310
g, 1 mmol) under argon was added, over a period of 10
min, a 0.1 M solution of NaOEt (1.2 mmol, 12 ml) and
either SnCl2Me2 or SnClt2Bu2 (0.5 mmol). After 4 h of
stirring, the solution was evaporated to dryness, the
addition of dichloromethane gave a white solid corre-
sponding to NaCl which was filtered through celite.
The resulting solution was concentrated to give white
solids (1, 2) which were filtered off and dried in vacuo.
Yields: 1, 82%; 2, 79%. IR(film): n(P.O)=1144 cm−1
Sn(1)ꢀC(2)
Sn(1)ꢀO(5)
Sn(1)ꢀC(1)
2.171(9)
2.176(5)
2.184(10)
Sn(1)ꢀO(6)
Sn(1)ꢀS(1)
2.332(5)
2.451(2)
Bond angles
C(2)ꢀSn(1)ꢀO(5)
C(2)ꢀSn(1)ꢀC(1) 130.6(4)
O(5)ꢀSn(1)ꢀC(1)
C(2)ꢀSn(1)ꢀO(6)
O(5)ꢀSn(1)ꢀO(6) 168.4(2)
C(1)ꢀSn(1)ꢀO(6) 86.5(3)
C(2)ꢀSn(1)ꢀS(1) 113.0(3)
O(5)ꢀSn(1)ꢀS(1) 86.8(2)
C(1)ꢀSn(1)ꢀS(1) 115.2(3)
99.5(3)
O(6)ꢀSn(1)ꢀS(1)
C(11)ꢀC(1)ꢀSn(1)
C(12)ꢀC(1)ꢀSn(1)
C(13)ꢀC(1)ꢀSn(1)
C(21)ꢀC(2)ꢀSn(1)
C(23)ꢀC(2)ꢀSn(1)
C(22)ꢀC(2)ꢀSn(1)
C(101)ꢀS(1)ꢀSn(1)
P(1)ꢀO(5)ꢀSn(1)
82.7(2)
109.7(7)
107.5(7)
109.4(6)
110.2(7)
111.0(6)
107.4(6)
100.5(3)
127.6(3)
93.6(3)
89.1(3)
1
(1); 1151 cm−1 (2). H-NMR (CDCl3): 1, l=7.6 (m,
2H), 7.57–7.31 (m, 20H), 7.26 (m, 2H), 6.9 (m, 2H),
7.01 (m, 2H), 0.61 (s, J119SnꢀH=87 Hz and J117SnꢀH
=
83.4 Hz, 6H, CH3); 2, l=7.68–7.26 (m, 28H), 1.05 (s,
t
J
SnꢀH=106 Hz, 18H, Bu). 31P-NMR (CDCl3) 1, l=
equatorial sites and the oxygen atoms of the water and
the oxidised phosphine ligand occupying the apical
positions, the O(5)ꢀSnꢀO(6) angle being 168.4(2)°. The
33.9 ppm (s); 2, l=33.1 ppm (s). 119Sn-NMR (CDCl3):
1, l= −90.8 (d, JSnꢀP=55 Hz), 2 l= −97.4 (d,
J
SnꢀP=20 Hz). 1 C38H34O2P2S2Sn (767.44): Calc. C,
,
SnꢀO bond lengths are SnꢀO(6) 2.332(5) A, typical of
59.45; H, 4.45; S, 8.35; Found: C, 60.1; H, 4.5; S, 8.0%;
2 C44H46O2P2S2Sn (851.63): Calc. C, 62.05; H, 5.45; S,
7.5; Found: C, 61.6; H, 5.3; S, 7.05%. MS(LSISM+)
(m/z) (%)=766 (5) (1), 849 (6) (2). LM (ohm−1 cm2
mol−1)=2 (1), 1 (2).
other tin complexes with water molecules in their struc-
,
ture [25], and SnꢀO(5) 2.176(5) A. In the bipyramidal
equatorial plane, are two SnꢀC and one SnꢀS bonds,
with angles: C(2)ꢀSnꢀC(1) 130.6(4), C(2)ꢀSnꢀS(1)
113.0(4) and C(1)ꢀSnꢀS(1) 115.2(3)°. The SnꢀC bond
,
lengths are SnꢀC(1) 2.184(10) and SnꢀC(2) 2.171(9) A,
3.4. Preparation of [SnR2(OPPh2C6H4S)]TfO R=Me
(3a), Bu (4a)
that are in the range of other di-tert-butyl–tin com-
t
,
plexes [26]. The SnꢀS distance is 2.451(2) A, similar to
those found in the complex [Au2Sn(tBu)2(C6F5)2-
To a solution of [SnMe2(OPPh2C6H4S)2] (0.076 g, 0.1
mmol) or [SntBu2(OPPh2C6H4S)2] (0.085 g, 0.1 mmol)
in acetone (30 ml) was added HTfO (0.1 mmol, 9 ml).
After 4 h of stirring, the solution was concentrated, the
addition of diethyl ether gave white solids (3a, 4a)
which were filtered off and dried in vacuo. Yields: 3a,
90%, 4a, 85%. IR(film): n(P.O)=1143 cm−1 (3a),
,
(SC6H4PPh2)2] namely 2.444(3) and 2.434(3) A [13].
3. Experimental
3.1. General procedures
1145 cm−1 (4a). H-NMR (CDCl3): 3a, l=7.81 (m,
1
Infrared spectra were recorded on a Perkin–Elmer
1H), 7.61–7.39 (m, 11H), 7.15 (m, 1H), 6.78 (m, 1H),
0.92 (s, JSnꢀH=87 Hz, 6H, CH3); 4a, l=8 (m, 1H),
883 spectrophotometer, over the range 4000–200 cm−1
,
1
by using Nujol mulls between polyethylene sheets, H
and 31P-NMR spectra were recorded on a Bruker 300
or Varian UNITY 300 in CDCl3 solutions; chemical
shifts are quoted relative to SiMe4 (1H) and H3PO4
(external 31P). The C, H and S analyses were performed
in a Perkin–Elmer 2400 microanalyser. Conductivities
were measured in acetone with a Philips PW 9509
apparatus. Mass spectra were recorded on a VG Au-
tospec, by liquid secondary ion mass spectrometry
(LSIMS+) using nitrobenzylalcohol as matrix.
7.66–7.48 (m, 11H), 7.2 (m, 1H), 6.81 (m, 1H), 1.28 (s,
t
J
SnꢀH=114.4 Hz, 18H, Bu). 31P-NMR (CDCl3) 3a,
l=39.7 ppm (s), 4a, l=45.4 ppm (s). 119Sn-NMR
(CDCl3): 3a, l= −90.3 (d, JSnꢀP=50 Hz); 4a, l=
−169.2 (d,
JSnꢀP=78 Hz). 3a C21H20O4PS2F3Sn
(606.74): Calc. C, 41.55; H, 3.3; S, 10.55; Found: C,
41.1; H, 2.95; S, 9.9; 4a C27H32O4PS2F3Sn (691.35):
Calc. C, 46.9; H, 4.65; S, 9.3; Found: C, 47.1; H, 4.9; S,
9.7. MS(LSISM+) (m/z) (%)=459 (100) (3a), 543
(100) (4a). LM (ohm−1 cm2 mol−1)=78 (3a), 95 (4a).
3.2. Starting materials
3.5. Preparation of [SnR2(OPPh2C6H4S)]ClO4 R=Me
(3b), Bu (4b)
t
OPPh2C6H4SH [27] was obtained according to the
literature procedures, the rest of the reagents were used
as supplied.
To a solution of [SnMe2(OPPh2C6H4S)2] (0.076 g, 0.1
mmol) or [SntBu2(OPPh2C6H4S)2] (0.088 g, 0.1 mmol)

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E. Cerrada et al. / Polyhedron 20 (2001) 2863–2867
in acetone (30 ml) was added a solution of HClO4 0.1
M (0.1 mmol, 1 ml). After 1 h of stirring at reflux
temperature Na2SO4 was added and filtered through
Celite. The resulting solution was concentrated and the
addition of diethyl ether (20 ml) gave white solids (3b,
4b) which were filtered off and dried in vacuo. Yields:
3b, 86%, 4b, 75%. IR(film): n(P.O)=1143 cm−1 (3b),
0.0450, vR=0.1174 for all data. In the final Fourier
synthesis the electron density fluctuates in the range
−3
,
1.077 to −0.957 e A
.
4. Supplementary material
1
1145 cm−1 (4b). H-NMR (CDCl3): 3b, l=7.84 (m,
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC no. 163479 for compound 4b
(excluding structure factors). Copies of this information
may be obtained free of charge from The Director,
CCDC, 12 Union Road, Cambridge CB2 1EZ, UK
(Fax: +44-1223-336033; e-mail: deposit@ccdc.cam.
ac.uk or www: http://www.ccdc.cam.ac.uk)
1H), 7.79 (m, 1H), 7.62–7.13 (m, 11H), 7.1 (m, 1H),
0.97 (s, JSnꢀH=87 Hz, 6H, CH3), 4b l=8 (m, 1H),
7.6–7.44 (m, 11H), 7.3 (m, 1H), 6.8 (m, 1H), 1.28 (s,
t
J
SnꢀH=114 Hz, 18H, Bu). 31P-NMR (CDCl3) 3a, l=
39.5 ppm (s) (JSnꢀP=49 Hz), 4a, l=45.6 ppm (s)
(JSnꢀP=79 Hz). 3b C20H20O5PSClSn (557.57): Calc. C,
43.05; H, 3.6; S, 5.75; Found: C, 43.5; H, 3.2; S, 5.2; 4b
C26H32O5PSClSn (605.86): Calc. C, 51.5; H, 5.3; S, 5.2;
Found: C, 51.9; H, 5.2; S, 5.6. LM (ohm−1 cm2 mol−1
=82 (3b), 90 (4b).
)
Acknowledgements
3.6. Crystallography
We thank the Spanish Directorate General for
Higher Education and Scientific Research Grant PB98-
0542 for financial support. M.B.H. thanks the Engi-
neering and Physical Sciences Research Council for
support of the X-ray facilities.
Single crystals were grown by diffusing diethyl ether
into an acetone solution of complex [SntBu2(OPPh2C6-
H4S)]ClO4 (4b) at low temperature, and mounted in
inert oil.
3.7. Crystal data and data collection parameters
C26H32ClO7PSSn, M=673.69, monoclinic, a=
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