Hydrazine Formation via Coupling of a Nickel(III)-NH₂ Radical

M(NH_x ) intermediates involved in N-N bond formation are central to ammonia oxidation (AO) catalysis, an enabling technology to ultimately exploit ammonia (NH₃ ) as an alternative fuel source. While homocoupling of a terminal amide species (M-NH₂ ) to form hydrazine (N₂ H₄ ) has been proposed, well-defined examples are without precedent. Herein, we discuss the generation and electronic structure of a Ni^III -NH₂ species that undergoes bimolecular coupling to generate a Ni^II ₂ (N₂ H₄ ) complex. This hydrazine adduct can be further oxidized to a structurally unusual Ni₂ (N₂ H₂ ) species; this releases N₂ in the presence of NH₃ , thus establishing a synthetic cycle for Ni-mediated AO. Distribution of the redox load for H₂ N-NH₂ formation via NH₂ coupling between two metal centers presents an attractive strategy for AO catalysis using Earth-abundant, late first-row metals.