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, OsO₃N^?, 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(η²‐NO)^?.