A Platinum(II) Metallonitrene with a Triplet Ground State

Metallonitrenes (M–N) are complexes with a subvalent, atomic nitrogen ligand that have been proposed as key reactive intermediates in nitrogen atom transfer reactions. However, in contrast to the common class of nitride complexes (Mo≡N) and organic nitrenes (R–N), authentic, persistent metallonitrenes remain elusive. We here report that the photolysis of a platinum(II) pincer azide complex enabled the crystallographic, spectroscopic, magnetic and computational characterization of a metallonitrene that is best described as a singly bonded, atomic nitrogen diradical ligand bound to platinum(II). The photoproduct exhibits selective C–H, B–H, and B–C nitrogen atom insertion reactivity. Mechanistic examination of aldehyde C–H amidation surprisingly reveals nucleophilic reactivity of the subvalent N-diradical ligand.