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

Olefin metathesis catalysts bearing chelating carbene ligands based on 8-vinylquinoline and 5-vinylquinoxaline were examined as initiators for Ring Opening Metathesis Polymerization. Model-polymerizations with these initiators were studied by differential scanning calorimetry and nuclear magnetic resonance. Results revealed a pronounced latency at room temperature and high activity at elevated temperatures. Combined solutions of the initiators and the monomers can even be stored for two weeks at room temperature. While no concomitant polymerization occurred during this time, polymerization of the mixtures took place upon heating.