Reductive Dimerization of CO by a Na/Mg(I) Diamide.

Sodium reduction of [{SiN}Mg] [{SiN} = {CHSiMeN(Dipp)}; Dipp = 2,6-PrCH] provides the Mg(I) species, [{SiN}MgNa], in which the long Mg-Mg bond (>3.2 Å) is augmented by persistent Na-aryl interactions. Computational assessment indicates that this molecule is best considered to comprise a contiguous tetrametallic core, a viewpoint borne out by its reaction with CO, which results in ethynediolate formation mediated by the dissimilar metal centers.