Cis-Dichloridobis(diethyl sulfide-κS)platinum(II) at 295 and 150 K

Article abstract of DOI:10.1107/S0108270107030417

The title compound, cis-[PtCl2(C4H10S)2], crystallizes in the space group P21/n with pseudo-square-planar coordination geometry. The orientation of the ethyl groups on the S atoms is staggered with respect to the coordination plane, giving the complex approximate C 2v symmetry. The complex does not form dimeric packing units with short Pt...S intra-dimeric distances as seen in some related complexes, but instead displays C - H...Cl inter-actions in three dimensions. These C - H...Cl - Pt contacts are compared with those of related compounds reported in the Cambridge Structural Database, which show a frequency maximum in the range 120-170° for the C - H...Cl angle. International Union of Crystallography 2007.

Full text of DOI:10.1107/S0108270107030417

metal-organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
The packing arrangement of the complex may be described
as consisting of layers of complexes in the (101) plane formed
by CÐHÁ Á ÁCl interactions with HÁ Á ÁCl distances in the range
ISSN 0108-2701
cis-Dichloridobis(diethyl sulfide-jS)
platinum(II) at 295 and 150 K
Christian Hansson
Organic Chemistry, Department of Chemistry, Lund University, PO Box 124,
SE-221 00 Lund, Sweden
ꢀ
Ê
2.78±2.90 A and CÐHÁ Á ÁCl angles in the range 135±157 at
Correspondence e-mail: christian.hansson@organic.lu.se
150 K (Table 2 and Fig. 2). However, if the interval is extended
Ê
to 3.20 A, it is seen that the layers are connected by four
Received 13 June 2007
Accepted 21 June 2007
Online 14 July 2007
additional ClÁ Á ÁH contacts to form a three-dimensional
network. Two of these interactions between the layers have
CÐHÁ Á ÁCl angles in the range 108±110ꢀ, whereas the other
two are in the same range as the interactions within the layers.
With the exception of the molecules that straddle 0 0 12,
The title compound, cis-[PtCl2(C4H10S)2], crystallizes in the
space group P21/n with pseudo-square-planar coordination
geometry. The orientation of the ethyl groups on the S atoms
is staggered with respect to the coordination plane, giving the
complex approximate C2v symmetry. The complex does not
form dimeric packing units with short PtÁ Á ÁS intradimeric
distances as seen in some related complexes, but instead
displays CÐHÁ Á ÁCl interactions in three dimensions. These
CÐHÁ Á ÁClÐPt contacts are compared with those of related
compounds reported in the Cambridge Structural Database,
which show a frequency maximum in the range 120±170ꢀ for
the CÐHÁ Á ÁCl angle.
which have a short H7AÁ Á ÁH7Aii contact of 2.31 A, the
Ê
symmetry centres create voids of different sizes (symmetry
codes are given in Tables 1 and 2). Four molecules form a ring
around 0 0 0 with H1AÁ Á ÁCl2iii and H2BÁ Á ÁCl2iv contacts of
1
Ê
2.90 and 3.12 A, respectively. Dimers are formed around 0 2 0,
v
Ê
with a H4BÁ Á ÁCl2 distance of 3.10 A. A ring of four molecules
is formed around 21 0 0, with contacts H1AÁ Á ÁCl1iii and
H5AÁ Á ÁCl2vi having HÁ Á ÁCl distances of 2.80 and 2.78 A,
Ê
respectively. The PtÁ Á ÁS2i distance across the ring is
Ê
5.3822 (10) A.
There are no signi®cant differences between the PtÐCl or
PtÐS bond lengths of cis-PtCl2(Me2S)2 and the title
compound. The SÐPtÐS angle at 150 K is 87.90 (3)ꢀ in the
diethyl sul®de complex and 94.75ꢀ in the complex with dms
ligands, probably re¯ecting the different ways in which the two
ligands orientate around the PtII ion. Since one of the dms
ligands has one methyl group placed in the coordination plane,
Comment
In the solid state, the complex cis-PtCl2(Me2S)2 (Horn et al.,
1990) has one dimethyl sul®de (dms) ligand in a staggered and
one in an eclipsed orientation with respect to the PtCl2S2 coor-
dination plane. A similar situation has been observed in cis-
PtCl2(tx)2 (tx = 1,4-thioxane, SC4H8O; Bugarcic et al., 1993).
Both structures form centrosymmetric dimeric units with
Ê
PtÁ Á ÁS distances of 3.58 and 3.59 A for the dimers [cis-
PtCl2(tx)2]2 and [cis-PtCl2(Me2S)2]2, respectively. On the other
hand, the complex cis-PtCl2(Ph2S)2 (Johansson et al., 2001)
does not form a centrosymmetric unit with a short PtÁ Á ÁS
distance but is stabilized by CÐHÁ Á ÁCl interactions. In order
to gain more information on the formation of dimeric packing
units with a short PtÁ Á ÁS distance, the title complex cis-
PtCl2(Et2S)2, (I), has been examined.
The title complex possesses a pseudo-square-planar coor-
dination geometry, with angles around the Pt atom in the
range 87.40 (4)±91.43 (5)ꢀ at 295 K and 87.90 (3)±90.75 (4)ꢀ at
150 K. Selected bond distances and angles for the 150 K
structure are shown in Table 1. Both diethyl sul®de ligands are
orientated in a staggered manner with one ethyl group above
and one beneath the coordination plane. The organic groups
of the two sul®de ligands are directed away from each other
and the complex adopts approximately C2v symmetry (Fig. 1).
Figure 1
The numbering scheme for (I) at 150 K. The displacement ellipsoids are
drawn at the 30% probability level.
Acta Cryst. (2007). C63, m361±m363
DOI: 10.1107/S0108270107030417
# 2007 International Union of Crystallography m361

metal-organic compounds
the ligand demands more space and thus the SÐPtÐS angle
becomes larger, mostly at the expense of the neighbouring SÐ
PtÐCl angle. The sul®de ligands in the trans isomer of
PtCl2(Et2S)2 (Skvortsov et al., 1994) are staggered with respect
to the coordination plane and the complex posseses Ci
symmetry.
molecules in which the orientation of the ethyl groups is
similar to that seen in the title compound, but exceptions do
occur. The complex (8-methoxynaphthyl)platinum chloride
bis(diethyl sul®de) (Wehman et al., 1988) contains one diethyl
sul®de ligand with ethyl groups in staggered orientation, and
one which is turned so that one methylene carbon is
approximately in the coordination plane, i.e. a similar orien-
tation to that seen in cis-PtCl2(Me2S)2. However, this orien-
tation is probably governed by the steric demand of the
8-methoxynaphthyl ligand.
The so-called Kitaigorodsky packing index (KPI), i.e. the
ratio between occupied volume and the total unit-cell volume,
has been calculated using the VOID option in PLATON
(Spek, 2003) for the title compound at 295 and 150 K, and for
the related complexes cis-PtCl2(Me2S)2, cis-PtCl2(Ph2S)2, cis-
PtCl2(tx)2 and their trans counterparts (Table 3). No H-atom
positions were reported for trans-PtCl2(Et2S)2 and cis/trans-
PtCl2(tx)2, so H atoms had to be added to the structures before
the KPI could be calculated. The observed range of KPI, viz.
0.65±0.73, is within the interval proposed for organic mol-
ecules of 0.65±0.77 (Kitaigorodsky, 1973). The KPI of cis-
PtCl2(Me2S)2 is larger than the KPI of the title compound,
indicating that the former complex is able to pack more ef®-
ciently.
When comparing cis and trans isomers of compounds with
the general formula PtCl2(S-donor)2, it is observed that the
trans isomer often seems to be more densely packed than the
corresponding cis isomer (Table 3). However, the differences
are small, <3%. The difference in density for the title
compound at 295 and 150 K is 3.5%, and the volume expan-
sion coef®cient (1/V dV/dT) is 2.3 Â 10 4 K 1, indicating that
thermal expansion properties are very important for these
types of compounds, and no general conclusion about packing
ef®ciency between cis and trans complexes can be drawn.
The title compound does not form dimeric packing units of
the type seen in cis-PtCl2(Me2S)2 and cis-PtCl2(tx)2. A
dimerization with short PtÁ Á ÁS interactions requires a reor-
ientation of one of the thioether ligands. The cost in energy for
this must be compensated by the combined effect of the
dimerization and the energy of packing the dimers. There
seems to be a delicate balance between these factors since cis-
PtCl2(Me2S)2 and cis-PtCl2(tx)2 form dimers with short PtÁ Á ÁS
interactions while cis-PtCl2(Et2S)2 and cis-PtCl2(Ph2S)2 do
not. It may be possible for cis-PtCl2(Et2S)2 to form more CÐ
HÁ Á ÁCl contacts in three dimensions than cis-PtCl2(Me2S)2,
since more H atoms are present, and the formation of CÐ
HÁ Á ÁCl interactions probably stabilizes the packing of the title
compound. This is supported by data in the Cambridge
Structural Database (CSD, Version 5.28, November 2006
release; Allen, 2002) which has been searched using ConQuest
software (Bruno et al., 2002). Most PtIIÐCl complexes in the
CSD have CÐHÁ Á ÁCl angles in the range 120±170ꢀ. CÐ
H(methyl)Á Á ÁCl and CÐH(methylene)Á Á ÁCl angles have
means of 141 and 139ꢀ, respectively, for a HÁ Á ÁCl cut-off
Ê
Ê
distance of 3.2 A. A cut-off distance of 3.0 A increases the
mean values to 150 and 145ꢀ for CÐH(methyl)Á Á ÁCl and CÐ
H(methylene)Á Á ÁCl, respectively (see deposited material).
The complexes [PtCl3(Me2S)] (Kukushkin et al., 1994), cis/
trans-PtCl2(Me2S)2 (Horn et al., 1990; Hansson et al., 2006)
and [PtCl(Me2S)3]+ (Hansson et al., 2003) make up a series of
complexes with dms and chloride ligands in different ratios.
Dimeric units with a short PtÁ Á ÁS interaction have been found
in cis-PtCl2(Me2S)2 (as discussed above) and [PtCl(Me2S)3]+,
but not in the other complexes in the series.
Experimental
Most of the 13 PtII complexes with one or more diethyl
sul®de ligands in the CSD (Allen, 2002) contain diethyl sul®de
K2PtCl4 (0.506 g, 1.21 mmol) was dissolved in 20 ml water. Diethyl
sul®de (3.7 ml, 34.3 mmol) was added, giving a dark-yellow precipi-
tate. The reaction mixture was stirred for 24 h. The yellow precipitate
which formed was ®ltered off and dried. Recrystallization from
acetone gave yellow±green crystals suitable for X-ray diffraction
experiments.
Compound (I) at 295 K
Crystal data
3
Ê
[PtCl2(C4H10S)2]
Mr = 446.35
V = 1483.30 (5) A
Z = 4
Monoclinic, P21=n
Mo Kꢁ radiation
ꢂ = 10.07 mm
T = 295 (1) K
0.24 Â 0.11 Â 0.06 mm
1
Ê
a = 10.7928 (2) A
Ê
b = 11.4223 (2) A
Ê
c = 12.2417 (2) A
ꢀ = 100.6190 (10)ꢀ
Data collection
Oxford Diffraction Xcalibur3
diffractometer
Absorption correction: analytical
(CrysAlis RED; Oxford
Diffraction, 2006)
14809 measured re¯ections
5157 independent re¯ections
3266 re¯ections with I > 2ꢃ(I)
Rint = 0.029
Figure 2
The hydrogen-bonded layer (101). Dashed lines indicate CÐHÁ Á ÁCl
interactions. [Symmetry code (viii) x + , y + , z 12; other symmetry
codes are as given in Table 2.]
1
2
1
2
Tmin = 0.257, Tmax = 0.618
ꢁ
m362 Christian Hansson
[PtCl2(C4H10S)2] and [PtCl2(C4H10S)2]
Acta Cryst. (2007). C63, m361±m363

metal-organic compounds
Re®nement
Table 3
Density and KPI for four thioether cis/trans complexes.
R[F2 > 2ꢃ(F2)] = 0.027
wR(F2) = 0.076
S = 1.00
122 parameters
H-atom parameters constrained
3
3
Compound formula
Density (Mg m
)
KPI
Ê
Áꢄmax = 1.72 e A
3
Ê
1.09 e A
5157 re¯ections
Áꢄmin
=
a
cis-PtCl2(Me2S)2
cis-PtCl2(Et2S)2 (295 K)b
cis-PtCl2(Et2S)2 (150 K)b
cis-PtCl2(Ph2S)2
d
2.52
2.00
2.07
1.81
2.39
2.60
2.06
1.83
2.37
0.698
0.654
0.676
0.666
0.728
0.726
0.675
0.674
0.730
c
Compound (I) at 150 K
cis-PtCl2(tx)2
trans-PtCl2(Me2S)2
trans-PtCl2(Et2S)2
trans-PtCl2(Ph2S)2
e
Crystal data
f
3
Ê
[PtCl2(C4H10S)2]
Mr = 446.35
Monoclinic, P21=n
V = 1435.00 (11) A
Z = 4
c
d
trans-PtCl2(tx)2
Mo Kꢁ radiation
1
Ê
Ê
a = 10.7598 (5) A
ꢂ = 10.40 mm
T = 150 (1) K
Notes: (a) Horn et al. (1990); (b) this paper; (c) Johansson et al. (2001); (d) Bugarcic et al.
(1993); (e) Hansson et al. (2006); (f) Skvortsov et al. (1994).
b = 11.1976 (5) A
Ê
c = 12.1559 (5) A
0.24 Â 0.11 Â 0.06 mm
ꢀ = 101.536 (4)ꢀ
For both determinations, data collection: CrysAlis CCD (Oxford
Diffraction, 2006); cell re®nement: CrysAlis RED (Oxford Diffrac-
tion, 2006); data reduction: CrysAlis RED; program(s) used to solve
structure: SHELXTL (Sheldrick, 1998); program(s) used to re®ne
structure: SHELXTL; molecular graphics: DIAMOND (Branden-
burg, 2000); software used to prepare material for publication:
CRYSTALS (Betteridge et al., 2003) and enCIFer (Allen et al., 2004).
Data collection
Oxford Diffraction Xcalibur3
diffractometer
Absorption correction: analytical
(CrysAlis RED; Oxford
Diffraction, 2006)
14202 measured re¯ections
5054 independent re¯ections
4061 re¯ections with I > 2ꢃ(I)
Rint = 0.023
Tmin = 0.222, Tmax = 0.635
Re®nement
R[F2 > 2ꢃ(F2)] = 0.027
wR(F2) = 0.080
S = 1.01
122 parameters
H-atom parameters constrained
Ê
Professor Ake Oskarsson is thanked for valuable discus-
sions. Financial assistance from the Royal Physiographic
Society in Lund, the Swedish National Research Council and
the Wallenberg Foundation is acknowledged.
3
Ê
Áꢄmax = 3.61 e A
3
Ê
1.19 e A
5054 re¯ections
Áꢄmin
=
Table 1
Selected geometric parameters (A, ) for (I) at 150 K.
ꢀ
Ê
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: SQ3085). Services for accessing these data are
described at the back of the journal.
Pt1ÐS2
Pt1ÐS1
Pt1ÐCl2
Pt1ÐCl1
2.2699 (9)
2.2736 (9)
2.3105 (10)
2.3159 (9)
S1ÐC3
S1ÐC1
S2ÐC5
S2ÐC7
1.815 (4)
1.820 (4)
1.812 (4)
1.820 (5)
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Pt1Á Á ÁS2i
5.3822 (10)
H7AÁ Á ÁH7Aii
2.31
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ꢀ
Ê
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DÐHÁ Á ÁA
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Ê
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È
C1ÐH1AÁ Á ÁCl1iii
C1ÐH1AÁ Á ÁCl2iii
C2ÐH2BÁ Á ÁCl2iv
C4ÐH4BÁ Á ÁCl2v
C5ÐH5AÁ Á ÁCl2vi
C6ÐH6BÁ Á ÁCl1vii
C8ÐH8BÁ Á ÁCl1ii
0.97
0.97
0.96
0.96
0.97
0.96
0.96
2.80
2.90
3.12
3.10
2.78
3.07
3.20
3.5504 (48)
3.7967 (46)
3.5602 (46)
3.9963 (50)
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3.4968 (50)
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135
154
110
157
141
108
139
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È
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Ê
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Ê
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È
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Â
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;
z ‡ 32; (iv) x ‡ 12,
1
2
y ‡ 12; z ‡ 12; (v) x ‡ 1; y; z ‡ 1; (vi) x
z ‡ 32.
,
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,
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2
1
2
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È
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Ê
atoms (methyl CÐH = 0.96 A and methylene CÐH = 0.97 A), with
Ê
Uiso(H) = 1.5Ueq(methyl C) and 1.2Ueq(methylene C). At 150 K, the
Ê
highest peak in the ®nal difference map is situated 1.94 A from C8
Ê
and 3.01 A from C2, while the lowest peak is 0.68 A from Pt1.
Ê
ꢁ
Acta Cryst. (2007). C63, m361±m363
Christian Hansson
[PtCl2(C4H10S)2] and [PtCl2(C4H10S)2] m363