Imidazole end-functionalized polycyclooctenes from chain-transfer ring-opening metathesis polymerization and aminolysis reactions

Abstract

Imidazole end-functionalized polycyclooctene derivatives were synthesized using a two-step procedure; combining ring-opening metathesis polymerization (ROMP)/cross-metathesis (CM) and aminolysis reaction. ROMP/CM of cyclooctene (COE) in the presence of methyl-10-undecenoate (MU) as a chain transfer agent in the presence of Grubbs first generation catalyst (G1) at 40 °C afforded mono ester end-functionalized (MF) as the major and bis ester end-functionalized (DF) polycyclooctene as the minor product. No isomerized mono ester end-functionalized (IMF) polycyclooctene was formed during G1 catalyzed ROMP/CM reactions. The post-polymerization modification of MF in the presence of 1-(3-aminopropyl) imidazole and different catalysts (Sn(Oct)2, Ti(OiPr)4 and triazabicyclodecene (TBD) in THF at 70 °C afforded imidazole end-functionalized polyolefins in excellent yields. All polymers were characterized by means of MALDI ToF-MS, 1H and 13C NMR spectrometry and Size Exclusion Chromatography (SEC) analyses. The solvent selectivity and catalyst screening experiments were carried out for both ROMP/CM and aminolysis reactions to determine the optimum reaction conditions.