Reactivity of Diaryl Bismuth Cations toward a Platinum(0) Complex: Oxidative Aryl Transfer

Reactions of three aryl-substituted bismuth cations, [BiPh2(SbF6)], [BiMes2(SbF6)], and [BiDipp2(SbF6)], with the Pt0 complex Pt(PCy3)2 have been investigated (Mes = 2,4,6-trimethyl-phenyl; Dipp = 2,6-di-iso-propyl-phenyl; Cy = cyclohexyl). Unexpectedly, and in contrast with the reactivity of the recently reported methyl analogue [BiMe2(SbF6)], the formation of isolable metal-only Lewis pairs [(Cy3P)2Pt→BiAr2(SbF6)] is not observed (Ar = aryl). Instead, an unprecedented bismuth-to-platinum oxidative aryl transfer is witnessed to give the PtII complexes [PtAr(PCy3)2(SbF6)], along with the suggested bismuthinidene intermediates BiAr. Attempts to trap these fleeting intermediates with an ortho-quinone led to a PtII semiquinone radical complex.