Paddlewheel Dicobalt Complexes with Metal Centers Having Various Oxidation States.

Herein, we report the characterization of a family of two bidentate silyldiamide-stabilized digonal lantern dinuclear cobalt complexes [Co2{μ-κ2-Ph2Si(N-2,6-iPr2C6H3)2}]x- (x = 0 (1), 1 (2), and 2 (3)) in order to study the interaction between two Co atoms. Complexes 1-3 can be interconverted by redox reactions. The Co2-containing fragments in 1-3 are almost isostructural due to the steric congestion of the supporting ligands, leading to their high rigidity. In contrast to the reported shortest CoI-CoI bonds in similar digonal dicobalt complexes, the homounivalent dicobalt compound 3 instead has the longest Co-Co bond length among 1-3. The calculated Co-Co bond orders are in agreement with the experimental data, with the order decreasing from 2 (1) to 1 (3) as the valence of the central Co2 unit decreases.