Facile Reductive Silylation of UO22+ to Uranium(IV) Chloride

General reductive silylation of the UO₂²⁺ cation occurs readily in a one‐pot, two‐step stoichiometric reaction at room temperature to form uranium(IV) siloxides. Addition of two equivalents of an alkylating reagent to UO₂X₂(L)₂ (X=Cl, Br, I, OTf; L=triphenylphosphine oxide, 2,2′‐bipyridyl) followed by two equivalents of a silyl (pseudo)halide, R₃Si‐X (R=aryl, alkyl, H; X=Cl, Br, I, OTf, SPh), cleanly affords (R₃SiO)₂UX₂(L)₂ in high yields. Support is included for the key step in the process, reduction of U^VI to U^V. This procedure is applicable to a wide range of commercially available uranyl salts, silyl halides, and alkylating reagents. Under this protocol, one equivalent of SiCl₄ or two equivalents of Me₂SiCl₂ results in direct conversion of the uranyl to uranium(IV) tetrachloride. Full spectroscopic and structural characterization of the siloxide products is reported.