Synthesis of [POCOP]-pincer iron and cobalt complexes via Csp3–H activation and catalytic application of iron hydride in hydrosilylation reactions

Abstract

C_sp3–H bond activation in diphosphinito pincer ligand (Ph₂PO(o-C₆H₂-(4,6-^tBu₂)))₂CH₂ (1) (POCH₂OP) was achieved by Fe(PMe₃)₄ and CoMe(PMe₃)₄ to afford complexes (POCHOP)Fe(H) (PMe₃)₂ (2) and (POCHOP)Co(PMe₃)₂ (4) under mild conditions. Hydrido iron complex 2 reacted with iodomethane via the elimination of methane to deliver complex (POCHOP)FeI(PMe₃) (3). The ligand replacement in Ni(PMe₃)₄ by 1 gave rise to nickel(0) complex (POCH₂OP)Ni(PMe₃)₂ (5) without C_sp3–H bond activation of the pincer ligand (1). It was confirmed that the hydrosilylation of aldehydes and ketones could be effectively catalyzed by hydrido iron complex 2. Complexes 2–5 were characterized by spectroscopic methods and X-ray single crystal diffraction analysis.