Reversible Dihydrogen Activation and Hydride Transfer by a Uranium Nitride Complex

Cleavage of dihydrogen is an important step in the industrial and enzymatic transformation of N 2 into ammonia. The reversible cleavage of dihydrogen was achieved under mild conditions (room temperature and 1 atmosphere of H 2 ) by the molecular uranium nitride complex, [Cs{U(OSi(O t Bu) 3 ) 3 } 2 (μ‐N)] 1, leading to a rare hydride–imide bridged diuranium(IV) complex, [Cs{U(OSi(O t Bu) 3 ) 3 } 2 (μ‐H)(μ‐NH)], 2 that slowly releases H 2 under vacuum. This complex is highly reactive and quickly transfers hydride to acetonitrile and carbon dioxide at room temperature, affording the ketimide‐ and formate‐bridged U IV species [Cs{U(OSi(O t Bu) 3 ) 3 } 2 (μ‐NH)(μ‐CH 3 CHN)], 3 and [Cs{U(OSi(O t Bu) 3 ) 3 } 2 (μ‐HCOO)(μ‐NHCOO)], 4 .