Activation of Si–Si and Si–H bonds at Pt: a catalytic hydrogenolysis of silicon–silicon bonds

Abstract

The activation of Ph₂HSiSiHPh₂ and Me₃SiSiMe₃ at [Pt(PEt₃)₃] (1) yielded the products of oxidative addition. The formation of [Pt(SiHPh₂)₂(PEt₃)₂] (2) as a mixture of the cis and trans isomers appears to proceed quantitatively, whereas a conversion to give cis-[Pt(SiMe₃)₂(PEt₃)₂] (3) was not complete. Treatment of 1 with one equivalent of H₂SiPh₂ led to cis-and trans-[Pt(H)(SiHPh₂)(PEt₃)₂] (cis-4, trans-4) together with the dinuclear complex [(Et₃P)₂(H)Pt(μ-SiPh₂)(μ–η²-HSiPh₂)Pt(PEt₃)] (5). In contrast, HSiMe₃ reacts with [Pt(PEt₃)₃] to yield cis-[Pt(H)(SiMe₃)(PEt₃)₂] (7) exclusively. Catalytic reactions of dihydrogen with the disilanes Ph₂HSiSiHPh₂ or Me₃SiSiMe₃ in the presence of catalytic amounts of [Pt(PEt₃)₃] (1) led to the products of hydrogenolysis, H₂SiPh₂ and HSiMe₃. The conversion of Me₃SiSiMe₃ is much slower and needs higher temperature to proceed.