Ring‐Opening polymerization of cycloolefins with catalysts derived from ruthenium and iridium

Abstract

Abstract An investigation was carried out on the polymerization of norbornene, cyclopentene and cyclooctene by the following iridium and ruthenium compounds: chlorobis(cyclooctene)iridium ( 1 ), carbonylchlorobis(cyclooctene)iridium ( 2 ), trifluoroacetatobis(cyclooctene)iridium ( 3 ), chloroiridic(IV) acid ( 4 ), dichloro(2,7‐dimethylocta‐2,6‐diene‐1,8‐diyl)‐ruthenium ( 5a ), and bis(trifluoroacetato)‐(2,7‐dimethylocta‐2,6‐diene‐1,8‐diyl)ruthenium ( 5b ). All the above catalysts were found to be very active for the polymerization of norbornene via ring‐opening. Iridium catalysts were practically inactive for the polymerization of cyclopentene and cyclooctene, but gave copolymers of norbornene with cyclopentene and cyclooctene via ring‐opening. The ruthenium catalysts displayed no activity for the polymerization of cyclopentene and cyclooctene, but it was found that after treatment with H 2 they became active for the polymerization of cyclopentene. The results obtained from the reaction of norbornene and aliphatic olefins suggest that the above catalysts act by metathesis. The particular features of these catalysts were examined.