Nuclear magnetic resonance investigations of configurational nonrigidity in dinuclear platinum(<scp>IV</scp>) complexes. Part 1. Ring reversal, pyramidal inversion, and novel fluxional rearrangements in [(PtXMe₃)₂(MeECHREMe)](E = S or Se) complexes

Abstract

Dinuclear complexes of the type DL-[(PtXMe3)2(MeECHREMe)](E = S or Se; X = Cl, Br, or I; R = H or Me) have been isolated for the first time and shown by 1H n.m.r. spectroscopy to exhibit a remarkable variety of intramolecular dynamic processes. Accurate n.m.r. bond-shape fittings have enabled barrier energies for up to four distinct dynamic processes to be separately determined. These processes involve six-membered ligand ring reversal, pyramidal inversion of the S or Se atoms, S or Se atom switching between Pt atom pairs, and a random cleavage of halogen-bridge bonds allowing rotations which cause scrambling of the Pt–Me environments.