PHOTOCATALYSIS INDUCED BY LIGHT-SENSITIVE COORDINATION-COMPOUNDS

Electronic excitation of both WERNER-type complexes and light-sensitive organometallics may lead to coordinatively unsaturated complex fragments, metal complexes with unusual formal oxidation numbers of the central atoms, free ligands and ligand oxidation, products, respectively, which may exhibit catalytic activity. For the description of processes involving photo-generation of catalytically active species and subsequent catalyzed reactions, the terms photoinduced catalytic reactions and photoassisted reactions, respectively, have been applied. General features of photoinduced catalytic and photoassisted reactions and their applications are discussed. Particular emphasis is placed on the use of photosensitive coordination compounds as catalysts for organic syntheses. Photooxygenation of phenols and terpenes in the presence of copper(I)/(II) complexes and metalloporphyrins, respectively, as well as photoinduced cyclisation reactions of unsaturated hydrocarbons in the presence of azido complexes of nickel(II), palladium(II) and platinum(II) are discussed in more detail. © 1990 IUPAC