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

摘要

The activation of Ph_2HSiSiHPh_2 and Me _3SiSiMe_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_2SiPh_2 led to cis-and trans-[Pt(H)(SiHPh_2)(PEt_3)_2] (cis-4, trans-4) together with the dinuclear complex [(Et_3P) _2(H)Pt(μ-SiPh_2)(μ-η_2-HSiPh _2)Pt(PEt_3)] (5). In contrast, HSiMe3 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_2HSiSiHPh_2 or Me _3SiSiMe_3 in the presence of catalytic amounts of [Pt(PEt_3)_3] (1) led to the products of hydrogenolysis, H_2SiPh_2 and HSiMe_3. The conversion of Me _3SiSiMe_3 is much slower and needs higher temperature to proceed.