Synthesis and Reactivity of a Mixed-Sandwich Uranium(IV) Primary Amido Complex

Facile NH bond activation of ammonia by the tucked-in mixed-sandwich complex U(?-COTTIPS2)(eta(5):kappa(1)-C5Me4CH2) (1; COTTIPS2 = 1,4-{(SiPr3)-Pr-i}(2)C8H6) yields a rare example of a primary amido complex, U(COTTIPS2)Cp*(NH2) (2). 2 reacts with CO2 to form the carbamate complex U(COTTIPS2)Cp*(kappa(2)-O2CNH2) (3) and may be deprotonated with KH in the presence of 18-crown-6 to form the primary imido complex [U(COTTIPS2)Cp*(NH)][K(18C6)] (4). 2 and 3 have been crystallophically characterized by X-ray diffraction.