Syntheses of the cyclic platinum(II) thiolate complexes [Pt{SCH2C(O)CH2}(PPh3)2] and [{Pt[SCH2C(O)CH2](PPh3)}2]

Abstract

Treatment of [Pt(η²-RCHCHR)(PPh₃)₂](R = H or Ph) with 1,3-dichloroacetone gave the chloroacetonyl complex cis-[PtCl{CH₂C(O)CH₂Cl}(PPh₃)₂]1 which readily cyclised in high yield to the thiolate complex [[graphic omitted]H₂}(PPh₃)₂]2 by treatment with sodium sulfide. Complexes 1 and 2 have been fully characterised by IR and NMR spectroscopies, and by elemental analysis. Ligand substitution reactions of complex 2 with an excess of isocyanide RNC (R = Bu^t, Buⁿ or 2,6-xylyl), an excess of tri-n-butylphosphine or 1 equivalent of trimethyl phosphite in dichloromethane afforded the monosubstituted complexes [[graphic omitted]H₂}(PPh₃)(L)]). These complexes were typically isolated as a mixture of isomers, with the major isomer in each case having the PPh₃ ligand trans to CH₂. Treatment of complex 2 with an excess of trimethyl phosphite yielded the bis(phosphite) complex [[graphic omitted]H₂}{P(OMe)₃}₂]. Reaction of 2 with [Rh₂(µ-Cl)₂(CO)₄] afforded a mixture of products from which the thiolate-bridged dimeric complex [{[graphic omitted]H₂](PPh₃)}₂] was isolated and characterised by a single-crystal X-ray diffraction study, which confirmed the formulation of these complexes as five-membered ring thiolates.