Photochemical nitrogenation of alkanes and arenes by a strongly luminescent osmium(VI) nitrido complex

The search for a highly active nitrido complex that can transfer its nitrogen atom to inert organic molecules remains a challenge to chemists. In this regard, the use of solar energy to generate a reactive nitrido species is an appealing strategy to solve this problem. Here we report the design of a strongly luminescent osmium(VI) nitrido compound, [Os-VI(N) (NO2-L) (CN)(3)](-) (NO2-OsN) with emission quantum yield (Phi) and life time (tau) of 3.0% and 0.48 mu s, respectively in dichloromethane solution. Upon irradiation with visible light, this complex readily activates the aliphatic C-H bonds of various hydrocarbons, including alkanes. The excited state of NO2-OsN can undergo ring-nitrogenation of arenes, including benzene. Photophysical and computational studies suggest that the excited state of NO2-OsN arises from ON ligand to Os N charge transfer transitions, and as a result it possesses [Os = N-center dot] nitridyl character and is highly electrophilic.