Reduction and Hydrogenation of a Diazene by a (β‐Diketiminato)nickel Hydrazide

A (β‐diketiminato)nickel(II) hydrazido(1–) complex [L t Bu Ni(η 2 ‐N 2 H 3 )], { 1 , L t Bu = [HC(C t BuNC 6 H 3 { i Pr} 2 ) 2 ] – } has been obtained by treatment of [L t Bu NiBr] with hydrazine. In a reaction of 1 with two equivalents of the azo compound diisopropyl azodicarboxylic ester (adc–O i Pr) the Ni(N 2 H 3 ) entity acts as both a hydrogenating and a reducing agent: diisopropyl hydrazidodicarboxylate (hdc–O i Pr) is formed, and more adc–O i Pr is reduced by two electrons. The resulting (adc–O i Pr) 2– is found as a ligand in the ultimate nickel product complex, the trinuclear nickel(II) compound [L t Bu Ni(μ‐adc–O i Pr)Ni(μ‐adc–O i Pr)NiL t Bu ] ( 2 ), in which two L t Bu Ni + units are linked by a [Ni II (adc–O i Pr) 2 ] 2– moiety. The hypothesis that L t Bu Ni I species are acting as intermediates was supported by the independent finding that 2 can also be obtained by reaction of [L t Bu Ni(OEt 2 )] with adc–O i Pr.