trans-Tetra­iodidobis(tri-p-tolyl­phosphine oxide-κO)tin(IV)

Marina Hitosugi-Levesque; Joseph M Tanski

doi:10.1107/S1600536808023945

. 2008 Aug 6;64(Pt 9):m1107. doi: 10.1107/S1600536808023945

trans-Tetraiodidobis(tri-p-tolylphosphine oxide-κO)tin(IV)

Marina Hitosugi-Levesque ^a, Joseph M Tanski ^a,^*

PMCID: PMC2960702 PMID: 21201573

Abstract

The centrosymmetric title compound, [SnI₄(C₂₁H₂₁OP)₂], is a monomeric complex that displays a nearly octahedral coordination of tin(IV), with an Sn—O bond distance of 2.159 (2) Å and an average Sn—I bond distance of 2.79 (3) Å.

Related literature

For examples of structurally characterized tin(IV) halide complexes of phosphine oxide ligands, see: Tursina et al. (1985 ▶); Tursina, Aslanov et al. (1986 ▶); Tursina, Yatsenko et al. (1986 ▶); Tudela et al. (1993 ▶); Genge et al. (1999 ▶); Szymanska-Buzar et al. (2001 ▶); Davis, Clarke et al. (2006 ▶); Davis, Levason et al. (2006 ▶); Caldwell & Tanski (2008 ▶). For related literature, see: Levason et al. (2003 ▶); Woollins (2003 ▶).

Experimental

Crystal data

[SnI₄(C₂₁H₂₁OP)₂]
M _r = 1266.99
Orthorhombic,
a = 18.6013 (11) Å
b = 11.9677 (7) Å
c = 19.3335 (11) Å
V = 4303.9 (4) Å³
Z = 4
Mo Kα radiation
μ = 3.57 mm⁻¹
T = 125 (2) K
0.20 × 0.20 × 0.05 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2007 ▶) T _min = 0.535, T _max = 0.842
53839 measured reflections
5331 independent reflections
4841 reflections with I > 2σ(I)
R _int = 0.032

Refinement

R[F ² > 2σ(F ²)] = 0.019
wR(F ²) = 0.048
S = 1.07
5331 reflections
235 parameters
H-atom parameters constrained
Δρ_max = 0.56 e Å⁻³
Δρ_min = −0.49 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808023945/pv2089sup1.cif

e-64-m1107-sup1.cif^{(21.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808023945/pv2089Isup2.hkl

e-64-m1107-Isup2.hkl^{(261.1KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Selected geometric parameters (Å, °).

Sn—O1	2.1590 (15)
Sn—I1	2.76735 (17)
Sn—I2	2.8158 (2)
O1—P1	1.5207 (16)

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O1—Sn—O1ⁱ	180
O1—Sn—I1	89.84 (4)
O1ⁱ—Sn—I1	90.16 (4)
I1—Sn—I1ⁱ	180
O1—Sn—I2ⁱ	93.59 (4)
O1ⁱ—Sn—I2ⁱ	86.41 (4)

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Symmetry code: (i) Inline graphic .

Acknowledgments

This work was supported by Vassar College. X-ray facilities were provided by the US National Science Foundation (grant No. 0521237 to JMT).

supplementary crystallographic information

Comment

Tin(IV) iodide may be readily prepared by oxidation of tin metal with iodine (Woollins, 2003). A relatively weak Lewis acid, SnI₄ nevertheless forms complexes with phosphines and phosphine oxides (Genge et al. 1999; Davis, Clarke et al. 2006; Caldwell & Tanski, 2008). The phosphine oxide complexes are chiefly obtained by air oxidation of the phosphine ligands in the presence of the tin(IV) halide (Levason et al. 2003). The crystal and molecular structures of the bis(triphenyl phosphine oxide) adducts of SnX₄, where X = F, Cl, Br and I, have all been previously reported. In the case of the fluoride, trans-[Ph₃PO]₂SnF₄, the the phospine oxides are mutually trans (Davis, Clarke et al. 2006). The chloride, cis-[Ph₃PO]₂SnCl₄, exhibits cis phospine oxides ligands (Tursina et al. 1985; Szymanska-Buzar et al. 2001), although it has been reported that both the cis and trans isomers are observed in solution by ³¹P NMR (Davis, Levason et al. 2006<). The structures of both cis-[Ph₃PO]₂SnBr₄ and trans-[Ph₃PO]₂SnBr₄ are known for the bromide (Tudela et al. 1993; Tursina, Yatsenko et al. 1986). In the structure of the iodide, the triphenyl phosphine oxide ligands of cis-[Ph₃PO]₂SnI₄ are found to be cis (Tursina, Aslanov et al. 1986). As reported here, tri(p-tolyl) phosphine oxide results in an iodide complex wherein the phosphine oxide ligands are found to be trans.

Reaction of SnI₄ with tri(p-tolyl) phosphine, (p-CH₃C₆H₄)₃P, in CHCl₃ in the presence of air afforded the title complex [(p-CH₃C₆H₄)₃PO]₂SnI₄, (I).

Complex (I) exhibits a nearly octahedral coordination at tin, which resides on a crystallographic inversion center. The phosphine oxide ligands are mutually trans, with an Sn—O distance of 2.159 (2) Å, and Sn—I distances of 2.7674 (2) and 2.8158 (2) Å. Relevant bond lengths and angles can be found in Table 1. Despite the p-CH₃ substituent and trans orientation of the phosphine oxide ligands in (I), the Sn—O and Sn—I distances in (I) are very similar to those found in cis-[Ph₃PO]₂SnI₄, wherein the Sn—O distances are 2.15 (2) and 2.11 (2) Å, and the Sn—I distances range from 2.781 (2) to 2.816 (2) Å (Tursina, Aslanov et al. 1986).

Experimental

Complex (I) was prepared by treating a chloroform (ca 10 ml) solution of SnI₄ (626 mg, 1.00 mmol) with an excess of (p-CH₃C₆H₄)₃P (647 mg, 2.13 mmol) in the presence of air. Suitable crystals for single-crystal X-ray analysis separated as orange plates within 2 weeks at room temperature.