Reductive Deprotonation and Dehydrogenation of Phenylhydrazine at a Nickel Center To Give a Nickel Diazenido Complex

The reaction of [LtBuNi­(OEt2)] (where LtBu = [HC­(CtBuNC6H3(iPr)2)2]−) with phenylhydrazine leads to the phenylhydrazido(1−) complex [LtBuNi­(η2-NPhNH2)] (1) with concomitant formation of H2. Treatment of 1 with potassium graphite in the presence of crown ether again leads to H2 evolution and affords the heterobimetallic complex [LtBuNi­(μ-η2:η2-NPhNH)]­K­(18-crown-6) containing the doubly deprotonated phenylhydrazido(2−) ligand. 1 can be converted into a phenyldiazenido complex [LtBuNi­(η1-NNPh)] in the course of a dehydrogenation reaction employing 1,2-diisopropylazo dicarboxylate (DIAD) as the oxidant.