Di-μ-chlorido-bis­[chloridobis(di­methyl sulfoxide-κO)tin(II)]

The structure of the title compound, [Sn₂Cl₄(C₂H₆OS)₄], contains dimers formed through weak Sn⋯Cl [3.691 (2) Å] inter­actions, resulting in a planar Sn₂Cl₂ core with an inversion center at the centre of the four-membered ring. The Sn^II atoms are penta­coordinated and have a distorted octa­hedral Ψ-SnCl₃O₂ coordination geometry. The O atoms from the dimethyl sulfoxide mol­ecules occupy trans positions, while the Cl atoms exhibit a meridional arrangement.

Related literature

For related tin chlorides, see: Kisenyi et al. (1985); Kiriyama et al. (1973). For the structure of free DMSO, see: Viswamitra & Kannan (1966).

Experimental

Crystal data

• [Sn₂Cl₄(C₂H₆OS)₄]

• M_r = 691.70

• Monoclinic, P 2₁ /c

• a = 11.1449 (17) Å

• b = 13.349 (2) Å

• c = 8.4394 (13) Å

• β = 103.728 (2)°

• V = 1219.7 (3) ų

• Z = 2

• Mo Kα radiation

• μ = 2.84 mm⁻¹

• T = 297 K

• 0.28 × 0.25 × 0.23 mm

Data collection

• Bruker SMART APEX CCD area-detector diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 2000) T_min = 0.469, T_max = 0.523

• 8630 measured reflections

• 2148 independent reflections

• 1853 reflections with I > 2σ(I)

• R_int = 0.062

Refinement

• R[F² > 2σ(F²)] = 0.050

• wR(F²) = 0.097

• S = 1.18

• 2148 reflections

• 105 parameters

• H-atom parameters constrained

• Δρ_max = 0.57 e Å⁻³

• Δρ_min = −0.72 e Å⁻³

Table 1
Selected geometric parameters (Å, °)

Cl1—Sn1	2.4767 (19)
Cl2—Sn1	2.4886 (19)
O1—Sn1	2.382 (5)
O2—Sn1	2.371 (5)

O2—Sn1—O1	166.36 (17)
O2—Sn1—Cl1	86.61 (13)
O1—Sn1—Cl1	85.99 (13)
O2—Sn1—Cl2	84.94 (14)
O1—Sn1—Cl2	84.15 (13)
Cl1—Sn1—Cl2	93.86 (7)

Data collection: SMART (Bruker, 2000); cell refinement: SAINT-Plus (Bruker, 2001); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Supporting information

S1. Comment

In an attempt to perform an oxidative addition of SnCl₂ to an organic halide, the title compound was isolated as a by-product.

The tin(II) dichloride crystallizes with two dimethylsulfoxide molecules which coordinate to the metal center in a trans fashion through the oxygen atoms [O1—Sn1—O2 = 166.36 (17)°] (Figure 1). The molecular units are connected in dimers through weak Sn···Cl interactions [Sn1···Cl1ⁱ = 3.691 (2) Å; symmetry code (i): -x, -y + 2, -z] trans to a Sn1—Cl2 bond [Cl2— Sn1···Cl1ⁱ = 164.85 (6)°]. This results in a planar Sn₂Cl₂ core with an inversion centre in the middle of the four-membered ring (Figure 2). The chlorine bridges are asymmetric and the endocyclic angles around chlorine atoms [Sn1—Cl1—Sn1ⁱ = 101.11 (5)°] are larger than the endocyclic angles around tin [Cl1—Sn1—Cl1ⁱ = 78.90 (6)°].

In the dimer unit the tin atom is pentacoordinated in a distorted pseudo-octahedral coordination geometry, with the two chlorine atoms from the same molecular unit in cis positions [Cl1—Sn1—Cl2 = 93.86 (7)°] and a bridging chlorine atom trans to the free position. In contrast, in SnCl₄.2DMSO (Kisenyi et al., 1985) the tin atom is hexacoordinated, with the oxygen atoms from the dimethylsulfoxide in cis position, while the structure of SnCl₂.2H₂O is described as pyramidal (Kiriyama et al., 1973) with only one water molecule bonded to the metal center.

The Sn—O bond lengths (Table 1) are similar to those found in SnCl₂.2H₂O [2.331 (5) Å], but larger than in SnCl₄.2DMSO [2.110 (9) and 2.110 (8) Å]. The Sn—Cl bonds follow the same pattern; those in SnCl₄.2DMSO [range: 2.369 (3) - 2.406 (3) Å] are larger than in the title compound [Sn1—Cl1 = 2.4767 (19) Å, Sn1—Cl2 = 2.4886 (19) Å] and SnCl₂.2H₂O [2.500 (2) and 2.562 (2) Å]. This is consistent with the fact that SnCl₂ is a weaker Lewis acid than SnCl₄.

The S—O bonds [S1—O1 = 1.531 (5) Å, S2—O2 = 1.519 (5) Å] show a decrease of multiplicity from the S═O bond in the free ligand [S═O = 1.471 Å], due to the oxygen-tin interaction. The S—C bond lengths vary between 1.727 (11) and 1.779 (8) Å, which are similar with those from the free DMSO molecule (Viswamitra & Kannan, 1966).

In the strucure the dimers are stacked along the a axis and form layers stacking along the b axis, with alternate arrangement of the dimeric units in consecutive layers (Figure 3).

Related literature

For related tin chlorides, see: Kisenyi et al. (1985); Kiriyama et al. (1973). For the structure of free DMSO, see: Viswamitra & Kannan (1966).

S2. Experimental

The title compound was isolated as a by-product after the workup of the reaction between SnCl₂ to an organic halide performed in hot dimethyl sulfoxide (DMSO).

S3. Refinement

All hydrogen atoms were placed in calculated positions using a riding model, with C—H = 0.96 Å and with U_iso= 1.5U_eq (C) for methyl H.

The data collection was done with 2 second irradiation time per frame over the complete sphere for a total data collection time of 2 hours. An earlier attempt to measure a crystal with a 10 second irradiation time per frame resulted in crystal decay after approximately 3 hours.

Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SAINT-Plus (Bruker, 2001); data reduction: SAINT-Plus (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures

	Fig. 1. : View of the title compound showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level and H atoms as spheres of arbitrary radii.
	Fig. 2. : Intermolecular interactions (represented with dashed lines) showing the formation of dimers in crystal structure of the title compound. Symmetry codes as in Table 1.
	Fig. 3. : Crystal packing of the title compound. View down the a axis.

Di-µ-chlorido-bis[chloridobis(dimethyl sulfoxide-κO)tin(II)]

Crystal data

[Sn2Cl4(C2H6OS)4]	F(000) = 672
Mr = 691.70	Dx = 1.883 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3345 reflections
a = 11.1449 (17) Å	θ = 2.4–26.6°
b = 13.349 (2) Å	µ = 2.84 mm^−1
c = 8.4394 (13) Å	T = 297 K
β = 103.728 (2)°	Block, colourless
V = 1219.7 (3) Å^3	0.28 × 0.25 × 0.23 mm
Z = 2

Data collection

Bruker SMART APEX CCD area-detector diffractometer	2148 independent reflections
Radiation source: fine-focus sealed tube	1853 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.062
ϕ and ω scans	θmax = 25.0°, θmin = 2.4°
Absorption correction: multi-scan (SADABS; Bruker, 2000)	h = −13→13
Tmin = 0.469, Tmax = 0.523	k = −15→15
8630 measured reflections	l = −10→10

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.050	H-atom parameters constrained
wR(F^2) = 0.097	w = 1/[σ^2(Fo^2) + (0.0208P)^2 + 2.685P] where P = (Fo^2 + 2Fc^2)/3
S = 1.18	(Δ/σ)max = 0.001
2148 reflections	Δρmax = 0.57 e Å^−3
105 parameters	Δρmin = −0.72 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.128 (4)

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
C1	0.5033 (7)	0.8276 (6)	−0.0501 (11)	0.068 (2)
H1A	0.5258	0.8292	0.0670	0.102*
H1B	0.5703	0.8529	−0.0918	0.102*
H1C	0.4856	0.7598	−0.0864	0.102*
C2	0.3399 (8)	0.8695 (7)	−0.3317 (9)	0.069 (2)
H2A	0.3327	0.7980	−0.3425	0.103*
H2B	0.4060	0.8924	−0.3775	0.103*
H2C	0.2639	0.9002	−0.3886	0.103*
C3	0.0141 (10)	1.1657 (9)	0.422 (2)	0.140 (6)
H3A	−0.0474	1.1587	0.3220	0.211*
H3B	0.0195	1.2346	0.4557	0.211*
H3C	−0.0083	1.1254	0.5051	0.211*
C4	0.2396 (11)	1.1408 (8)	0.5967 (12)	0.101 (4)
H4A	0.1994	1.1045	0.6677	0.152*
H4B	0.2439	1.2105	0.6254	0.152*
H4C	0.3216	1.1150	0.6077	0.152*
Cl1	0.1548 (2)	1.07531 (15)	−0.0095 (3)	0.0633 (5)
Cl2	0.40441 (17)	0.95628 (17)	0.2850 (2)	0.0614 (6)
O1	0.2681 (4)	0.8512 (4)	−0.0601 (6)	0.0534 (13)
O2	0.1396 (5)	1.0145 (4)	0.3674 (6)	0.0600 (14)
S1	0.37123 (18)	0.90252 (13)	−0.1217 (2)	0.0469 (5)
S2	0.1554 (2)	1.12668 (15)	0.3945 (3)	0.0617 (6)
Sn1	0.18486 (4)	0.91864 (3)	0.15234 (6)	0.0448 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.054 (5)	0.064 (5)	0.090 (6)	0.006 (4)	0.025 (5)	0.007 (5)
C2	0.079 (6)	0.073 (6)	0.055 (5)	−0.015 (5)	0.018 (4)	−0.008 (4)
C3	0.074 (8)	0.075 (7)	0.267 (19)	0.011 (6)	0.029 (9)	−0.027 (9)
C4	0.139 (10)	0.070 (7)	0.080 (7)	0.004 (6)	−0.003 (7)	−0.012 (5)
Cl1	0.0684 (13)	0.0577 (12)	0.0648 (12)	0.0102 (10)	0.0178 (10)	0.0151 (10)
Cl2	0.0490 (11)	0.0818 (14)	0.0511 (11)	−0.0116 (10)	0.0073 (9)	0.0026 (10)
O1	0.056 (3)	0.053 (3)	0.059 (3)	−0.009 (2)	0.028 (3)	−0.010 (2)
O2	0.079 (4)	0.045 (3)	0.062 (3)	−0.004 (3)	0.030 (3)	−0.011 (2)
S1	0.0549 (11)	0.0371 (10)	0.0520 (11)	−0.0037 (8)	0.0194 (9)	−0.0055 (8)
S2	0.0799 (15)	0.0487 (12)	0.0594 (13)	−0.0044 (10)	0.0225 (11)	0.0024 (9)
Sn1	0.0439 (4)	0.0407 (3)	0.0514 (4)	−0.0045 (2)	0.0147 (2)	0.0007 (2)

Geometric parameters (Å, º)

C1—S1	1.764 (8)	C3—H3C	0.9600
C1—H1A	0.9600	C4—S2	1.751 (10)
C1—H1B	0.9600	C4—H4A	0.9600
C1—H1C	0.9600	C4—H4B	0.9600
C2—S1	1.779 (8)	C4—H4C	0.9600
C2—H2A	0.9600	Cl1—Sn1	2.4767 (19)
C2—H2B	0.9600	Cl2—Sn1	2.4886 (19)
C2—H2C	0.9600	O1—S1	1.531 (5)
C3—S2	1.727 (11)	O1—Sn1	2.382 (5)
C3—H3A	0.9600	O2—S2	1.519 (5)
C3—H3B	0.9600	O2—Sn1	2.371 (5)
S1—C1—H1A	109.5	S2—C4—H4C	109.5
S1—C1—H1B	109.5	H4A—C4—H4C	109.5
H1A—C1—H1B	109.5	H4B—C4—H4C	109.5
S1—C1—H1C	109.5	S1—O1—Sn1	123.0 (3)
H1A—C1—H1C	109.5	S2—O2—Sn1	127.5 (3)
H1B—C1—H1C	109.5	O1—S1—C1	105.2 (4)
S1—C2—H2A	109.5	O1—S1—C2	104.0 (3)
S1—C2—H2B	109.5	C1—S1—C2	98.7 (4)
H2A—C2—H2B	109.5	O2—S2—C3	103.9 (5)
S1—C2—H2C	109.5	O2—S2—C4	105.6 (4)
H2A—C2—H2C	109.5	C3—S2—C4	97.4 (7)
H2B—C2—H2C	109.5	O2—Sn1—O1	166.36 (17)
S2—C3—H3A	109.5	O2—Sn1—Cl1	86.61 (13)
S2—C3—H3B	109.5	O1—Sn1—Cl1	85.99 (13)
H3A—C3—H3B	109.5	O2—Sn1—Cl2	84.94 (14)
S2—C3—H3C	109.5	O1—Sn1—Cl2	84.15 (13)
H3A—C3—H3C	109.5	Cl1—Sn1—Cl2	93.86 (7)
H3B—C3—H3C	109.5	Sn1—Cl1—Sn1^i	101.11 (5)
S2—C4—H4A	109.5	Cl1—Sn1—Cl1^i	78.90 (6)
S2—C4—H4B	109.5	Cl2—Sn1—Cl1^i	164.85 (6)
H4A—C4—H4B	109.5
Sn1—O1—S1—C1	108.4 (4)	S2—O2—Sn1—Cl1	−24.9 (4)
Sn1—O1—S1—C2	−148.3 (4)	S2—O2—Sn1—Cl2	69.2 (4)
Sn1—O2—S2—C3	129.3 (7)	S1—O1—Sn1—O2	−5.1 (10)
Sn1—O2—S2—C4	−128.7 (5)	S1—O1—Sn1—Cl1	52.2 (3)
S2—O2—Sn1—O1	32.3 (10)	S1—O1—Sn1—Cl2	−42.1 (3)

Symmetry code: (i) −x, −y+2, −z.