Dalton communications. Preparation, crystal structure and fluxional behaviour of σ-S-bonded palladium and platinum complexes of the Ph4P2N4S2R–(R = Me or But) anions

Abstract

The reaction of the Ph₄P₂N₄S₂R^– anions (R = Me or Bu_t), generated from 1,5-Ph₄P₂N₄S₂ and the appropriate alkyllithium reagent, with cis- or trans-[MCl₂(PEt₃)₂](M = Pd or Pt) produces the complexes [MCl(PEt₃)₂(Ph₄P₂N₄S₂R)](R = Me, M = Pd or Pt; R = Bu^t, M = Pt) shown by X-ray crystallography (M = Pd, R = Me) to involve σ-S bonding of the P₂N₄S₂ ring to the metal; variable-temperature ³¹P NMR spectra of these complexes indicate a significant energy barrier to rotation about the M–S bond of 41–46 kJ mol^–1.