Abstract
<jats:p>The mechanism of ketone hydrosilylation catalyzed by a dicopper(I) monohydride PNNP complex was investigated through a combined computational and experimental study. Systematic evaluation of various catalytic pathways excluded a conventional hydride insertion pathway, as well as alternative options involving bimetallic oxidative addition and hypervalent silicon intermediates, converging instead on a single mechanism consistent with all experimental observations. This pathway commences with a stepwise metal–ligand cooperative activation of HSiPh3, followed by metal–metal cooperative preorganized coupling of the stabilized silyl nucleophile with the activated ketone. A bimetallic silyl migration and ligand-assisted protonation releases the hydrosilylation product. Notably, the hydride ligand acts as a spectator that stabilizes the dicopper core rather than participating directly in substrate transformation. These findings establish a nonclassical hydrosilylation mechanism in which metal–metal and stepwise metal–ligand cooperativity operate synergistically, illustrating how cooperative bimetallic architectures can access reaction pathways unavailable to mononuclear catalysts.</jats:p>