A Co(I) synthon, Na+[BP3iPr]CoI]– (1), reacts with PhSiH3 or SiH4 to generate unusual {[BP2iPr](SiH2R)CoH2}=Si={H2Co[BP3iPr]} species (R = Ph (2a), H (2b); [BPxiPr] = κx-PhB(CH2PiPr2)x) containing multiply-bonded Co=Si=Co or “silicide” cores. These complexes result from activations of Si–H and Si–C bonds to produce the central Si atoms via a mechanism that does not involve redistribution of the parent silane. The solid-state molecular structure of 2a is consistent with Co=Si multiple-bonding interactions. Solution-state NMR and IR spectroscopies have been used to probe the extent of the Co=Si and Si---H interactions. Isolation of the base-stabilized silylene [BP3iPr]Co(H)2=SiHPh(DMAP) (3) via treatment of 1 with PhSiH3 in the presence of 4-dimethylaminopyridine (DMAP) suggests that the formation of 2 occurs through an initial double Si–H activation of the parent silane. A DFT treatment of the model complex {[BP2Me](H2SiPh)CoH2}=Si={H2Co[BP3Me]} (2*) shows that bonding in the Co=Si=Co core consists of four 3c-2e interactions formed from the Si 3s and 3p orbitals and Co 3d orbitals.

Extrusion of dicobalt silicide cores via activation of all bonds at RSiH3 (R = H, Ph) by [(tris-Phosphinoborate)CoI]–

2019 Fall National Meeting

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