Lantern-Like Diplatinum(III)-Catalyzed Redox-Free Borylation or Silylation of Alkynes

Abstract

Binuclear platinum(III) complexes were known for their high index of antitumor activity and a lower associated nephrotoxicity. However, the chemistry and reactivity of binuclear platinum(III) compounds have not yet been explored to the same extent as those of platinum(II) and platinum(IV) species. Here, we reported the first binuclear platinum-catalyzed hydrosilylation, monoborylation and diboration reaction of alkynes with excellent selectivity and yield. Moreover, the mechanistic investigation by control experiments, kinetic isotope effect (KIE) study, Hammett plots, NMR spectra, UV−vis spectra, and X-ray photoelectron spectroscopy (XPS) analysis reveal that the Pt(III)₂-catalyzed reactions pass through a σ-bond metathesis process rather than the two-electron redox processes of the mononuclear platinum catalysis. Moreover, there are two different rate-determining steps, in which the migratory insertion step dominates the rate of electron deficient substates and σ-bond metathesis process dominates electron rich counterparts, respectively.