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

Abstract

AbstractPhotolysis of RuCl3(η1‐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(η1‐ON)(PPh3)2. Metal‐to‐ligand charge‐transfer (MLCT) excitation of the isoelectronic phenylazo complex, RuCl3(η1‐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(η1‐N2)(PPh3)2.