Reversible Dihydrogen Activation and Hydride Transfer by a Uranium Nitride Complex

Abstract: Cleavage of dihydrogen is an important step in the industrial and enzymatic transformation of N2 into ammonia. The reversible cleavage of dihydrogen was achieved under mild conditions (room temperature and 1 atmosphere of H2) by the molecular uranium nitride complex, [Cs{U(OSi-(OtBu)3)3}2(m-N)] 1, leading to a rare hydride–imide bridged diuranium(IV) complex, [Cs{U(OSi(OtBu)3)3}2(m-H)(m- NH)], 2 that slowly releases H2 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 UIV species [Cs{U(OSi-(OtBu)3)3}2(m-NH)(m-CH3CHN)], 3 and [Cs{U(OSi-(OtBu)3)3}2(m-HCOO)(m-NHCOO)], 4.