Synthesis of 1-oxidopyridinium-2-thiolato- and pyridine-2-thiolato-complexes of nickel, palladium, and platinum

Abstract

Quinoline N-oxide reacts with K[PtCl₃(CH₂CH₂)] to give [PtCl₂(C₂H₄)(ONC₉H₇)] whereas 1-oxidopyridinium-2-thiol (1a) gives [Pt(SONC₅H₄)₂](3a) and an insoluble oligomeric material containing at least four Pt atoms; complex (3a) and the oligomer can also be synthesised from K₂[PtCl₄]. The oligomeric material can be cleaved by PPh₃ and PMe₂Ph to give [PtCl(SONC₅H₄)(PPh₃)](5) and [PtCl(SONC₅H₄)(PMe₂Ph)₂](6) respectively, and compound (3a) is converted by PPh₃into the monophosphine complex [Pt(SONC₅H₄)₂(PPh₃)](7a). The complex (7a) and an analogue [Pd(SONC₅H₄)₂(PPh₃)](7b) have been prepared from [MCl₂(PPh₃)₂] and the thallium salt of (1a), and related complexes [M(SC₅H₄N)₂(PPh₃)₂][M = Pt (8a) or Pd (8b)] have been similarly synthesised from the thallium salt of 2-mercaptopyridine. Evidence for intramolecular scrambling in (7) and (8) has been adduced from variable temperature ¹H n.m.r. spectra.