Vanadium-Catalyzed Terpolymerization of ?,?-Dienes with Ethylene and Cyclic Olefins: Ready Access to Polar-Functionalized Polyolefins

?,?-Dienes are an important class of monomers due to their utility in the synthesis of cyclopolyolefins and reactive polyolefin intermediates. In this contribution, the terpolymerization of two ?,?-dienes (i.e., 1,5-hexadiene and 1,7-octadiene) with ethylene and various cyclic olefins [i.e., norbornene (NB), 5-ethylidene-2-norbornene (ENB), and dicyclopentadiene (DCPD)] catalyzed by a chelated imido vanadium complex has been examined. The ENB and DCPD diene termonomers provide additional sites for post-polymerization functionalization. Vanadium-catalyzed terpolymerization of the investigated ?,?-dienes yields polyolefins with a high molecular weight (Mw up to 200 × 103 g mol-1), unimodal and narrow molecular weight distribution, subambient glass transition temperatures (-30 < Tg °C <-3), and a proper content of C-C bonds. Comprehensive NMR investigation of the obtained polymers revealed that subtle changes in the ?,?-diene size have important effects on the numerous combinations of insertion paths (ring closure vs ring opening), from which different repeating units with a C-C bond in the side or main polymer chain and cyclic units are installed. Finally, the poly(ethylene-ter-1,5-hexadiene-ter-NB) was subjected to thiol-ene addition using thioglycolic acid, methyl thioglycolate, and N-acetyl-l-cysteine to access polar-functionalized polyolefins with a degree of functionalization and properties dependent on the thiol substitution.