Synthesis and crystal structures of platinum (II) complexes with phosphine sulfide:: cis-dichloro[dimethylsulfoxide](triphenylphosphine sulfide) platinum (II) and (-)-cis-dichloro[(S)-methyl-p-tolylsulfoxide]-(triphenylphosphine sulfide) platinum (II)

The addition of triphenylphosphine sulfide (Ph3PS) to bis-sulfoxide platinum (II) complexes [Pt(Me2SO)(2)Cl-2] and (-)-[Pt(Me-p-Tol-SO)(2)Cl-2] yields mixed ligand complexes [Pt(Ph3PS)(Me2SO)Cl-2](1) and (-)-[Pt(Ph3PS)(Me-p-TolSO)Cl-2] (2), which are effective catalysts for hydrosilylation reaction. These mixed-ligand complexes were obtained in crystal state and analyzed by X-ray diffraction, H-1, P-31 P and Pt-195 NMR; 2 was also studied by circular dichroism spectroscopy. Both complexes exist in CDCl3 solution as a dynamic equilibrium of two geometric isomers with an approximate 1:10 ratio, but only cis-isomer is obtained on crystallization. The X-ray structures of the complexes have classical geometry, and phosphine sulfide and sulfoxides are coordinated via sulfur. The new structural data for simple platinum-Ph3PS coordination bond, unaffected by chelation or bridging, were evaluated. The lengths of this bond are 2.300(4) angstrom in 1 and 2.305(3) angstrom in 2, respectively. PtSP angle equals 105.7(2)degrees in 1 and 104.05(13)degrees in 2, the PtSP plane is almost perpendicular to the coordination plane. The static trans-influence of Ph3PS is estimated to be strong and close to that of S-coordinated Me2SO. The complex 2 exhibits strong circular dichroisin at a wavelength below 330 nm, caused both by inherent Me-p-TolSO stereogenic center and induced asymmetry of Ph3PS. (c) 2005 Elsevier B.V. All rights reserved.