Nuclear magnetic resonance investigations of configurational non-rigidity in dinuclear platinum(IV) complexes. Part 8. Fluxional properties of complexes [(PtXMe3)2(SCH2SCH2SCHMe)](X = Cl, Br or I)

Abstract

A synthetic route to the platinum(IV) complexes [(PtXMe₃)₂([graphic omitted]HMe)](X = Cl, Br or I) has been established. Solution NMR and other evidence favour the ligand adopting a boat conformation and bridging the two platinum(IV) centres across an –SCH₂S–portion of the ring, with the ring methyl group in an equatorial environment. Only very weak evidence was obtained for the existence of the –SCHMeS– bridged ligand complex despite the occurrence of a fluxional process involving 60° pivots of the ligand about individual S–Pt bonds which must proceed via the –SCHMeS– bridged species. Activation energies and a proposed mechanism for the process are presented. Some rare examples of ²J(Pt^IVPt^IV) scalar couplings are reported.