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

The activation of Ph(2)HSiSiHPh(2) and Me(3)SiSiMe(3) at [Pt(PEt(3))(3)] (1) yielded the products of oxidative addition. The formation of [Pt(SiHPh(2))(2)(PEt(3))(2)] (2) as a mixture of the cis and trans isomers appears to proceed quantitatively, whereas a conversion to give cis-[Pt(SiMe(3))(2)(PEt(3))(2)] (3) was not complete. Treatment of 1 with one equivalent of H(2)SiPh(2) led to cis-and trans-[Pt(H)(SiHPh(2))(PEt(3))(2)] (cis-4, trans-4) together with the dinuclear complex [(Et(3)P)(2)(H)Pt(μ-SiPh(2))(μ-η(2)-HSiPh(2))Pt(PEt(3))] (5). In contrast, HSiMe(3) reacts with [Pt(PEt(3))(3)] to yield cis-[Pt(H)(SiMe(3))(PEt(3))(2)] (7) exclusively. Catalytic reactions of dihydrogen with the disilanes Ph(2)HSiSiHPh(2) or Me(3)SiSiMe(3) in the presence of catalytic amounts of [Pt(PEt(3))(3)] (1) led to the products of hydrogenolysis, H(2)SiPh(2) and HSiMe(3). The conversion of Me(3)SiSiMe(3) is much slower and needs higher temperature to proceed.