Borane-Mediated Silylation of a Metal–Oxo Ligand

The addition of 1 equiv of HSiPh3 to UO2(Aracnac)2 (Aracnac = ArNC(Ph)CHC(Ph)O; Ar = 3,5-tBu2C6H3), in the presence of 1 equiv of B(C6F5)3, results in the formation of U(OSiPh3)(OB{C6F5}3)(Aracnac)2 (1), via silylation of an oxo ligand and reduction of the uranium center. The addition of 1 equiv of Cp2Co to 1 results in a reduction to uranium(IV) and the formation of [Cp2Co][U(OSiPh3)(OB{C6F5}3)(Aracnac)2] (2) in 78% yield. Complexes 1 and 2 have been characterized by X-ray crystallography, while the solution-phase redox properties of 1 have been measured with cyclic voltammetry.