Ring-opening metathesis polymerization of functionalized cyclooctene by a ruthenium-based catalyst in ionic liquid

This paper describes the synthesis of a novel monomer of 5-substituted cyclooctene with the pendant of imidazolium salt (7) and the ring-opening metathesis polymerization of the functionalized cyclooctenes (4 and 7) in CH₂Cl₂ and ionic liquid [bmim][PF₆] by a ruthenium-based catalyst RuCl₂(PCy₃)(SIMeS)(CHPh) (2). The polymerization, which was carried out in ionic liquid, afforded improved control over the molecular weight (M_n) and polydispersity of the resultant products (PDI <1.4). Furthermore, to facilitate the GPC measurement for molecular weight of polymers, the charged polymers (poly-7) were hydrolyzed to give uncharged polymers (poly-4*) by removing the imidazolium pendant from the polymer chains.