Silicon-hydrogen bond activation and hydrosilylation of alkenes mediated by CpCo complexes: a theoretical study.

Using DFT techniques, we show that triplet cyclopentadienylcobalt activates Si-H bonds to generate singlet silylcobalt hydrides without the intervention of sigma-silanes. The cobalt is configurationally unstable, as evidenced by the diastereoisomerization of derivatives bearing chiral silyl ligands. Inversion at the metal proceeds in the singlet state via a bridging hydride. We demonstrate that a two-state mechanism for the transformation of silyl hydride cobalt complexes into disilyl dihydride cobalt species is feasible. Our calculations predict that catalytic hydrosilylation of alkenes should be achievable in the coordination sphere of cyclopentadienylcobalt.