On Thiol-Ene Radical Coupling Reaction When Synthesis Of Abcl(2)Type Heteroarm Star Copolymer Containing Pdpa Arm

In this paper, we designed novel ABCL(2)-type heteroarm star copolymers, where A, B and C are poly(epsilon-caprolactone) (PCL), poly(2-(diisopropylamino) ethyl methacrylate) (PDPA) and poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) arms, respectively, and L is 4-([2,2 ':6 ',2 ''-terpyridine]-4 '-yl) phenyl (Tpyp) ligand group. In the final synthesis step, thiol-ene radical coupling was used to link PMPC chain onto PCL/PDPA copolymer to form a heteroarm star copolymer. However, it was found that the presence of the PDPA block with tertiary amine moieties led the thiol-ene radical coupling not to be achieved easily in common conditions. Herein we focus on investigating the photoinitiated thiol-ene coupling reaction. Finally, we achieve the reaction via selecting appropriate solvent. It is expected that the exploration can broaden application of thiol-ene radical reaction in synthesis of polymer architectures.