Substrate Redox Non-innocence Inducing Stepwise Oxidative Addition Reaction: Nitrosoarene C–N Bond Cleavage on Low-Coordinate Cobalt(0) Species

The reactions of nitroso­arenes with transition-metal species are fundamentally important for their relevance to metal-catalyzed transformations of organo-nitrogen compounds in organic synthesis and also the metabolization of nitroarenes and anilines in biology. In addition to the well-known reactivity of metal-mediated N–O bond activation and cleavage of nitroso­arenes, we present herein the first observation of a nitroso­arene C–N bond oxidative addition reaction upon the interaction of a three-coordinate cobalt(0) species [(IPr)­Co­(vtms)₂] with 2,4,6-tri­(tert-butyl)-1-nitroso-benzene (Ar*NO). The reaction produces a cobalt nitrosyl aryl complex, [(IPr)­Co­(Ar*)­(NO)] (1), with a bis­(nitroso­arene)cobalt complex, [(IPr)­Co­(η²-ONAr)­(κ¹-O-ONAr)] (2), as an intermediate. Spectroscopic characterizations, DFT calculations, and kinetic studies revealed that the redox non-innocence of nitroso­arene induces a stepwise pathway for the C–N bond oxidative addition reaction.