Ring-opening metathesis polymerization (ROMP) of N-cycloalkyl-7-oxanorbornene dicarboximides by well-defined ruthenium initiators

Ring-opening metathesis polymerization (ROMP) of exo-N-(1-adamantyl)-7-oxanorbornene-5,6-dicarboximide (AdONDI) (3a), exo-N-cyclohexyl-7-oxanorbornene-5,6-dicarboximide (ChONDI) (3b) and exo-N-phenyl-7-oxanorbornene-5,6-dicarboximide (PhONDI) (3c) using well-defined alkylidene ruthenium catalysts (PCy3)2(CI)2RuCHPh (I) and (1,3-dimesityl-4,5-dihydroimidazol-2-ylidene) (PCy3)CI2RuCHPh (II) was studied. The catalysts I and II gave polymers with around 70% and 50% trans vinylene content, respectively. The homopolymer of 3a had a Tg of 198 °C, while poly-3b showed a Tg of 122 °C. Copolymers of 3a, 3b and 3c with norbornene (NB) showed significant Tg increases over poly-NB.