Heterometallic Pt-Au complexes with μ-3 S bridging. Syntheses and structures of Pt 2 (PPh 3) 4(μ-SAuCl) 2·2CH 2Cl 2 and Pt 2(PPh 3) 4−(μ-S)(μ-SAuPPh 3)NO 3·0.5H 2O

Abstract

From Pt 2(PPh 3) 4(μ- S) 2 ( I) three heterometallic complexes can be prepared: Pt 2(PPh 3) 4(μ-SAuCl) 2 ( II), (Pt 2(PPh 3) 4(μ-SAuPPh 3) 2 2+ ( III) and Pt 2(PPh 3) 4- (μ-S)(μ-SAuPPh 3) + ( IV). Their preparation and properties are described. The crystal and molecular structures of II and the nitrate of IV has been investigated by X-ray diffraction analysis. II crystallizes in the monoclinic space group P2 1/ n, a = 18.359(2) b = 13.947(2), c = 14.588(2) Å, β = 100.982(7)°, V= 3666.9 Å 3, M r= 2138.28, Z = 2, D c = 1.94 Mg/m 3. Mo Kα radiation (graphite crystal monochromator, λ = 0.71069 Å, μ(Mo Kλ)= 85.13 cm −1, F(000) = 2032, T = 293 K. Final conventional R-factor = 0.039, Rw = 0.050 for 5084 unique reflections and 155 variables. IV crystallizes in the triclinic space group P 1 , a = 14.605(1), b = 15.989(2), c = 18.005(2) Å, α = 101.144(8)°, β = 100.773(7)°, γ = 91.201(2)°, V = 4045.4 Å 3, M r = 2033.75, Z = 2, D c = 1.66 Mg/m 3. Cu Kα radiation (graphite crystal monochromator, λ = 1.5418 Å), μ(Cu Kα) = 116.45 cm −1, F(000) = 1986, T = 293 K. Final conventional R-factor = 0.039 Rw = 0.051 for 8631 unique reflections and 297 variables. Both the structures were solved using SHELX84 and DIRDIF. The hinged square planar geometry of the parent I is kept in IV, where AuPPh 3 is bonded to one of the bridging S atoms. In II both bridging S atoms are bonded to AuCl and the hinging geometry is transformed into a nearly planar P 2PtS 2PtP 2 frame with the SAuCl vectors nearly perpendicular to it, one on each side of that plane. There are indications for weak AuPt bonding interactions. In IV and II the three-coordinated S-atoms have bond angles of about 90°. The structure of III is supported to be similar to II. Some reactions and interconversions of II, III and IV are described.