Ruthenium quinoline and quinoxaline complexes: Thermally triggered initiators for ring opening metathesis polymerization

The usage of four ruthenium carbene complexes initially described as ring closing metathesis catalysts as Ring Opening Metathesis Polymerization (ROMP) initiators for a set of representative liquid monomers at elevated temperatures was investigated. Initiators and the monomers and a mixture of ethyl ester and ethyl ester were prepared. Other chemicals were obtained from commercial sources and used without further purification. The solvent residual peak of CDCl 3 and acetone-d6 were used for referencing the NMR spectra. The reaction was quenched by adding water (50 mL) and sodium hydroxide solution (35%, 10 mL). A voluminous white precipitate was formed that was filtered off and the solution was concentrated. It was observed that through modification of the chelating carbene ligand and the stereochemistry of the initiator a tuning of the polymerization activity could be obtained.