Photolysis of Isoelectronic Ruthenium Nitrosyl and Diazonium Complexes in Frozen PVC Matrices: Retention of Dinitrogen on Ruthenium Following Photochemical Phenyl Radical Loss

Photolysis of RuCl 3 (η 1 ‐NO)(PPh 3 ) 2 in poly(vinyl chloride) (PVC) matrices at 85 K results in reversible linkage isomerism of the nitrosyl ligand to form the isonitrosyl complex RuCl 3 (η 1 ‐ON)(PPh 3 ) 2 . Metal‐to‐ligand charge‐transfer (MLCT) excitation of the isoelectronic phenylazo complex, RuCl 3 (η 1 ‐N 2 Ph)(PPh 3 ) 2 , has previously been shown to result in generation of the phenyl radical, presumably through decomposition a photogenerated diazenyl radical. Examination of this photolysis in a PVC matrix at cryogenic temperatures has permitted direct observation of an isotopically sensitive product band that may be assigned to a 17‐electron ruthenium dinitrogen species, suggesting that this photochemical decomposition does not proceed through formation of a diazenyl intermediate but through homolytic cleavage of the parent diazonium complex to give the phenyl radical and the 17‐electron RuCl 3 (η 1 ‐N 2 )(PPh 3 ) 2 .