Reversible Insertion of a C═C Bond into Magnesium(I) Dimers: Generation of Highly Active 1,2-Dimagnesioethane Compounds

The insertion of 1,1-diphenylethylene into the Mg–Mg bond of two magnesium(I) dimers, [( Ar Nacnac)Mg−] 2 (Ar = C 6 H 2 Me 3 -2,4,6 (Mes); C 6 H 3 Et 2 -2,6 (Dep)), yielding 1,2-dimagnesioethane products, [{( Ar Nacnac)Mg} 2 (μ-CH 2 CPh 2 )], is described. These reactions are readily reversible at room temperature and thus represent the first examples of room-temperature reversible redox processes for s-block metal complexes. The 1,2-dimagnesioethane products are highly activated magnesium alkyls and show unprecedented, uncatalyzed reactivity toward H 2, CO, and ethylene. Computational studies have investigated the mechanisms of all presented reaction types.