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

The [BP3iPr]Co(I) synthon Na(THF)6{[BP3iPr]CoI} (1, [BP3iPr] = κ3-PhB(CH2PiPr2)3–) reacts with PhSiH3 or SiH4 to form unusual {[BP2iPr](SiH2R)CoH2}═Si═{H2Co[BP3iPr]} species (R = Ph, 2a; R = H, 2b; [BP2iPr] = κ2-PhB(CH2PiPr2)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 [BP3iPr](H)2CoSiHPh(DMAP) (3). Complexes 2a,b eliminate RSiH3 upon thermolysis in the presence of DMAP to generate {[BP2iPr]Co(NC5H3NMe2)}═Si═{H2Co[BP3iPr]} (4).