One‐Electron Oxidation of [M(P t Bu 3 ) 2 ] (M=Pd, Pt): Isolation of Monomeric [Pd(P t Bu 3 ) 2 ] + and Redox‐Promoted C−H Bond Cyclometalation

Abstract

Oxidation of zero‐valent phosphine complexes [M(P t Bu 3 ) 2 ] (M=Pd, Pt) has been investigated in 1,2‐difluorobenzene solution using cyclic voltammetry and subsequently using the ferrocenium cation as a chemical redox agent. In the case of palladium, a mononuclear paramagnetic Pd I derivative was readily isolated from solution and fully characterized (EPR, X‐ray crystallography). While in situ electrochemical measurements are consistent with initial one‐electron oxidation, the heavier congener undergoes C−H bond cyclometalation and ultimately affords the 14 valence‐electron Pt II complex [Pt( κ 2 PC ‐P t Bu 2 CMe 2 CH 2 )(P t Bu 3 )] + with concomitant formation of [Pt(P t Bu 3 ) 2 H] + .