Role of Axial Ligation in Gating the Reactivity of Dimethylplatinum(III) Diimine Radical Cations

Huffman, B. L.; Lee, K. J.; Geer, A. M.; McKeown, B. A.; Jia, X.; Dickie, D. A.; Gunnoe, T. B.; Dempsey, J. L. Role of Axial Ligation in Gating the Reactivity of Dimethylplatinum(III) Diimine Radical Cations. Organometallics 2021, 40, 333-345.

Abstract

Electrochemical methods are coupled with chemical oxidant-based analytical strategies to evaluate the oxidative reactivity of the platinum(II) diimine complex (bpy)PtII(CH3)2 (bpy = 2,2′-bipyridine) in coordinating and noncoordinating media. Through this mechanistic analysis, we show that the one-electron oxidation of (bpy)PtII(CH3)2 generates a highly reactive, 15-electron PtIII radical cation and identify three reaction pathways that can follow this oxidation: radical–substrate dimerization, radical–radical dimerization, and oxidative disproportionation. Axial ligation of the initially generated [(bpy)PtIII(CH3)2]•+ species is a critical driver of this reactivity, gating the available mechanistic pathways and tuning the competition between radical–radical dimerization and oxidative disproportionation.

Last updated on 02/08/2021