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

Photolysis of RuCl3(eta(1)-NO)(PPh3)(2) in poly (vinyl chloride) (PVC) matrices at 85 K results in reversible linkage isomerism of the nitrosyl ligand to form the isonitrosyl complex RuCl3(eta(1)-ON)(PPh3)(2). Metal-to-ligand charge-transfer (MLCT) excitation of the isoelectronic phenylazo complex, RuCl3(eta 1-N2Ph) (PPh3)(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 RuCl3(eta(1)-N-2) (PPh3)(2).