Synthesis and reactivity of silyl cobalt complexes bearing a tetradentate phosphino silyl ligand via Si–H bond activation

Abstract

A novel Co(III) complex (o-(Ph2P)C6H4)3SiCoHCl (2) was synthesized by reaction of tris(phosphino)silyl ligand (o-(Ph2P)C6H4)3SiH (1) and CoCl(PMe3)3 with Si–H bond activation. Complex 2 was very stable to CO or CH3I. Co(I) complex (o-(Ph2P)C6H4)3SiCo(PMe3) (3) could be isolated in a yield of 72% when treatment of 2 with one equivalent of CH3Li in the presence of one equivalent of PMe3 with the formation of LiCl and the escape of one molecule of methane. Complex 3 could also be obtained by the reaction of 1 with Co(PMe3)4 or CoMe(PMe3)4 via elimination of H2 or CH4. The molecular structures of complexes 2 and 3 were determined by single crystal X-ray diffraction. Complex 2 has catalytic reactivity to the Kumada cross-cupling reactions.