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, [(ArNacnac)Mg-]2 (Ar = C6H2Me3-2,4,6 (Mes); C6H3Et2-2,6 (Dep)), yielding 1,2-dimagnesioethane products, [{(ArNacnac)Mg}2(μ-CH2CPh2)], 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 H2, CO, and ethylene. Computational studies have investigated the mechanisms of all presented reaction types.