A Masked Two-Coordinate Cobalt(I) Complex That Activates C–F Bonds

We report the isolation, characterization, and reactions of the unsaturated complex LtBuCo (LtBu = bulky β-diketiminate ligand). The unusual slipped κN,η6-arene binding mode in LtBuCo interconverts rapidly and reversibly with the traditional κ2N,N′ ligation mode upon binding of Lewis bases, making it a “masked” two-coordinate complex. The mechanism of this isomerization is demonstrated using kinetic studies. LtBuCo is a stable yet reactive synthon for low-coordinate cobalt(I) complexes and is capable of cleaving the C–F bond in fluorobenzene.