Dinitrogen Cleavage by a Heterometallic Cluster Featuring Multiple Uranium–Rhodium Bonds

Reduction
of dinitrogen (N2) is a major challenge for
chemists. Cooperation of multiple metal centers to break the strong
N2 triple bond has been identified as a crucial step in
both the industrial and the natural ammonia syntheses. However, reports
of the cleavage of N2 by a multimetallic uranium complex
remain extremely rare, although uranium species were used as catalyst
in the early Harber–Bosch process. Here we report the cleavage
of N2 to two nitrides by a multimetallic uranium–rhodium
cluster at ambient temperature and pressure. The nitride product further
reacts with acid to give substantial yields of ammonium. The presence
of uranium–rhodium bond in this multimetallic cluster was revealed
by X-ray crystallographic and computational studies. This study demonstrates
that the multimetallic clusters containing uranium and transition
metals are promising materials for N2 fixation and reduction.