Nuclear magnetic resonance investigations of configurational nonrigidity in dinuclear platinum(IV) complexes. Part 2. Pyramidal inversion and novel fluxional rearrangements in [(PtXMe3)2(MeEEMe)](E = S or Se) complexes

Abstract

New complexes of the type DL-[(PtXMe₃)₂(MeEEMe)](E = S or Se; X = Cl, Br, or I) have been isolated and shown by both X-ray and ¹H n.m.r. data to possess dinuclear structures involving halogen-bridge bonds. Barrier energies for (i) pyramidal inversion of S or Se atoms, (ii) S or Se atom switching between Pt atom pairs, and (iii) scrambling of PtMe groups, have been separately evaluated by dynamic n.m.r. methods. The relative probabilities of simultaneous and non-simultaneous mechanisms for the inversion of pairs of chalcogen atoms are assessed.