Synthesis and reactivity of a mixed-sandwich uranium(IV) primary amido complex

Facile N–H bond activation of ammonia by the “tucked-in” mixed-sandwich complex U(η-COTTIPS2)(η5:κ1-C5Me4CH2) (1; COTTIPS2 = 1,4-{SiiPr3}2C8H6) 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*(κ2-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