Properties and Reactivities of Zwitterionic Platinum(II)-ate Complexes Generated by Transforming Coordination of an Alkyne–Bisphosphine Ligand

Coordination of an alkyne–bisphosphine ligand with platinum­(II) precursors produced a structural reorganization in the ligand backbone to form stable zwitterionic platinum­(II) complexes bearing an anionic platinum center. The structural properties and reactivities of these complexes were investigated using X-ray crystallographic analyses, computational studies, and stoichiometric reactions involving oxidative addition and reductive elimination. These studies have shown that the enhanced nucleophilicity of the platinum center to alkyl halides promotes smooth oxidative addition and that the charge rebalance accelerates the dissociation of the halide anion from the platinum­(IV) intermediate, which is essential in the carbon–carbon bond-forming step.