Epoxidation of olefins catalyzed by chelating diphosphine-platinum(II) complexes. Ring-size and ring-shape effects on the catalytic activity

The epoxidation of 1-octene with H2O2has been examined by using as catalysts a homologous class of 10 (diphosphine)Pt-(CF3)(solv)+and 10 (diphosphine)Pt(CF3)(OH) type complexes, where the diphosphine has been systematically varied. All diphosphines contain two -PPh2groups but differ in the hydrocarbon chain linking together the two phosphorus atoms. The epoxidation reaction experimental conditions have been chosen in order to study the effect of the metal-diphosphine ring size and ring shape on the catalytic activity. It appears that diphosphine complexes with rigid, five-membered chelate rings prove to be the best catalysts.