PHOTOINDUCED RING-OPENING METATHESIS POLYMERIZATION (PROMP) OF STRAINED BICYCLIC OLEFINS WITH RUTHENIUM COMPLEXES OF THE TYPE TA(6)-ARENE(1))RU(ETA(6)-ARENE(2))](2-R)(6)](2+)() AND [RU(NC)

Upon UV irradiation, the complexes [(eta(6)-arene(1))Ru(eta(6)-arene(2 ))](2+) (toluene-4-sulfonate or trifluormethane-sulfonate as counter i on; examples for arene: benzene, toluene, mesitylene, hexamethylbenzen e, anisole, biphenyl, naphthalene) and [Ru(NC-R)(6)](2+) (tosylate or triflate as counter ion; R = methyl, ethyl, phenyl) are transformed in to active catalysts for ring opening metathesis polymerization (ROMP) of strained bicyclic olefins. The photoinduced ring opening metathesis polymerization (PROMP) is most efficient with sandwich complexes havi ng high quantum yields for the photochemically induced solvation of [( eta(6)-arene(1))Ru(eta(6)-arene(2))](2+) to [Ru(solvent)(6)](2+). With most of the complexes no (or only low) catalytic activity is observed in the absence of light. After the photolysis step, the mechanism of the polymerization is identical to ROMP reactions with thermally activ ated ruthenium catalysts. Good yields and high molecular weights are o btained with a catalyst concentration of 0.1-1%. A mechanistic model f or the initiation is presented. (C) 1995 John Wiley and Sons, Inc.