Photochemically induced intramolecular six-electron reductive elimination and oxidative addition of nitric oxide by the nitridoosmate(VIII) anion.

UV photolysis of the nitridoosmate(VIII) anion, OsO3 N(-) , in low-temperature frozen matrices results in nitrogen-oxygen bond formation to give the Os(II) nitrosyl complex OsO2 (NO)(-) . Photolysis of the Os(II) nitrosyl product with visible wavelengths results in reversion to the parent Os(VIII) complex. Formally a six-electron reductive elimination and oxidative addition, respectively, this represents the first reported example of such an intramolecular transformation. DFT modelling of this reaction proceeds through a step-wise mechanism taking place through a side-on nitroxyl Os(VI) intermediate, OsO2 (η(2) -NO)(-) .