Facile Dinitrogen and Dioxygen Cleavage by a Uranium(III) Complex: Cooperativity Between the Non-Innocent Ligand and the Uranium Center.

Activation of dinitrogen (N2 , 78 %) and dioxygen (O2 , 21 %) has fascinated chemists and biochemists for decades. The industrial conversion of N2 into ammonia requires extremely high temperatures and pressures. Herein we report the first example of N2 and O2 cleavage by a uranium complex, [N(CH2 CH2 NPi Pr2 )3 U]2 (TMEDA), under ambient conditions without an external reducing agent. The N2 triple bond breaking implies a UIII -PIII six-electron reduction. The hydrolysis of the N2 reduction product allows the formation of ammonia or nitrogen-containing organic compounds. The interaction between UIII and PIII in this molecule allows an eight-electron reduction of two O2 molecules. This study establishes that the combination of uranium and a low-valent nonmetal is a promising strategy to achieve a full N2 and O2 cleavage under ambient conditions, which may aid the design of new systems for small molecules activation.