The ability of the bis(imidazolyl)ketone ligand BMIK (bis(1-methyl-4,5-diphenylimidazolyl)ketone) to function as a redox active ligand has been investigated. The reduction of [M(BMIK)Cl] (M = Fe and Zn) complexes resulted in a pinacol-type coupling to form dinuclear complexes featuring very weak and abnormally elongated C-C bonds (1.729(5) and 1.708(3) Å for Fe and Zn, respectively). Oxidation of these complexes using ferrocenium in the presence of Cl ions regenerated the original [M(BMIK)Cl] complexes, showing the reversibility of the coupling process. This makes it a potentially interesting approach for the storage of electrons and application of the BMIK ligand as a redox active ligand.

In this study, the selective 1,2‐addition of diethylzinc to the ketone functionality of BMdiPhIK [bis(1‐methyl‐4,5‐diphenylimidazolyl)ketone] is shown. The reaction product is isolated in a dimeric form with a planar Zn2(µ‐O)2‐motif keeping the two monomers together. This compound can serve as a model for reactive intermediates in the catalytic alkylation of ketones with diorganozinc reagents. Hydrolysis of this binuclear zinc compound leads to isolation of the C‐alkylated product in 89 % yield. A reaction pathway is proposed in which BMdiPhIK initially coordinates to diethylzinc as a bidentate bis(nitrogen) ligand. This is followed by the homolytic cleavage of the Zn–Et bond and in‐cage recombination of the Et‐radical and the Zn‐coordinated ligand‐centered radical, which is mainly localized on the carbonyl moiety of the ligand.