Activations of all Bonds to Silicon (Si–H, Si–C) in a Silane with Extrusion of [CoSiCo] Silicide Cores

The [BP₃ ^iPr]Co(I) synthon Na(THF)₆{[BP₃ ^iPr]CoI} (1, [BP₃ ^iPr] = κ³-PhB(CH₂P ⁱPr₂)₃^-) reacts with PhSiH₃ or SiH₄ to form unusual {[BP₂ ^iPr](SiH₂R)CoH₂}═Si═{H₂Co[BP₃ ^iPr]} species (R = Ph, 2a; R = H, 2b; [BP₂ ^iPr] = κ²-PhB(CH₂P ⁱPr₂)₂) that result from activation of all Si-H and Si-C bonds in the starting silanes. Solution-spectroscopic data (multinuclear NMR, IR) for 2a,b, and the solid-state structure of 2a, indicate substantial Co═Si═Co multiple bonding and minimal interaction of the core Si atom with nearby hydride ligands. In the presence of 4-dimethylaminopyridine (DMAP), 1 reacts with PhSiH₃ to give [BP₃ ^iPr](H)₂CoSiHPh(DMAP) (3). Complexes 2a,b eliminate RSiH₃ upon thermolysis in the presence of DMAP to generate {[BP₂ ^iPr]Co(NC₅H₃NMe₂)}═Si═{H₂Co[BP₃ ^iPr]} (4).