Disilametallacycles as a platform for stabilizing M(II) and M(IV) (M = Fe, Ru) centers: Synthesis and characterization of half-sandwich complexes and their application to catalytic double silylation of alkenes and alkynes

A series of group 8 half-sandwich disilametallacycles, (η⁶- arene)M^II(Me₂SiC₆H₄SiMe ₂)L and (η⁶-arene)M^IV(H) ₂(Me₂SiC₆H₄SiMe₂) (M = Fe, Ru) in the formal oxidation states of M(II) and M(IV) were synthesized and characterized. Both the M(II) and the M(IV) oxidation states were effectively stabilized by the disilametallacycle skeleton, and facile interconversion between (η⁶-arene)M^II-dinitrogen, (η⁶- arene)M^II-carbonyl, and (η⁶-arene)M ^IV-dihydride complexes bearing a disilaferracycle framework was accomplished. These M(II) and M(IV) complexes can easily generate coordinatively unsaturated 16e disilametallacycles, (η⁶-arene)M ^II(Me₂SiC₆H₄SiMe₂), by dissociation of L or H₂, and stoichiometric and/or catalytic double silylation of alkenes and alkynes was realized thorough this 16e intermediate.