Catalysis of hydrosilylation: Part XXXIV. High catalytic efficiency of the nickel equivalent of Karstedt catalyst [{Ni(η-CH2CHSiMe2)2O}2{μ-(η-CH2CHSiMe2)2O}]

The nickel equivalent of Karstedt catalyst [{Ni(η-CH2CHSiMe2)2O}2{μ-(η-CH2CHSiMe2)2O}] (1) appeared to be a very efficient catalyst for dehydrogenative coupling of vinyl derivatives (styrene, vinylsilanes, vinylsiloxanes) with trisubstituted silanes HSi(OEt)3, HSiMe2Ph. The reaction occurs via three pathways of dehydrogenative coupling, involving formation of an unsaturated compound as the main product as well as a hydrogenated olefin (DS-1) pathway, hydrogenated dimeric olefin (DS-2) and dihydrogen (DC), respectively. The reaction is accompanied by side hydrosilylation. Stoichiometric reactions of 1 with styrene and triethoxysilane, in particular synthesis of the bis(triethoxysilyl) (divinyltetramethyldisiloxane) nickel complex 3 and the first documented insertion of olefin (styrene) into NiSi bond of complex 3, as well as all catalytic data have allowed us to propose a scheme of catalysis of this complex reaction by 1.