Reductive Cleavage of the N−N Bond of Hydrazine Induced by a Cationic Trinuclear Ruthenium Hexahydride Complex, [(Cp‘Ru)3(μ-H)6]X (Cp‘ = η5-C5Me5; X = 1/2 SO4, BF4, PF6, BPh4) and Dihydrogen

The reaction of the monocationic triruthenium hexahydride [(Cp‘Ru) 3 (μ-H) 6 ]X ( 1; X = 1 / 2 SO 4, BF 4, PF 6, BPh 4 ) with hydrazine leads to the formation of the mono(μ 3 -imido) complex (Cp‘Ru) 3 (μ 3 -NH)(μ-H) 3 ( 3 ) and the triruthenium pentahydride complex (Cp‘Ru) 3 (μ 3 -H) 2 (μ-H) 3 ( 2 ). Complex 1 is in equilibrium with 2 in the presence of NH 4 X or N 2 H 5 X, and complex 1 is regenerated upon treatment of 2 with such a protic salt. Complex 3 further reacts with hydrazine to yield the bis(μ 3 -imido) complex (Cp‘Ru) 3 (μ 3 -NH) 2 (μ-H) ( 4 ) as a result of cleavage of the nitrogen−nitrogen bond, which is formally catalyzed by a proton. Both 3 and 4 undergo hydrogenation to generate 2 together with ammonia. Thus, reductive cleavage of the nitrogen−nitrogen bond of hydrazine leading to ammonia is achieved by the use of the monocationic trinuclear hexahydride complex 1 and dihydrogen under conditions without any added proton source and a reducing agent.