Phenanthroline Derivatives as Efficient Organic Photocatalysts for Visible-Light-Mediated PET-RAFT Polymerization

Comprehensive SummaryPhenanthroline is an excellent and stable p-electron acceptor with a large conjugated chromophore. Phenanthroline derivatives are widely used in adsorption, photodegradation, solar cells, biology, and so on. At present, there are still limited organic molecules utilized to efficiently photocatalyze reversible-deactivation radical polymerization (RDRP). Therefore, the design of organic photocatalysts (OPCs) for RDRP remains a challenge. Herein, according to the strategy of combining the donor groups and weak acceptor groups, donor-acceptor (D-A) type OPCs based on phenanthroline were utilized for the first time in photoinduced electron transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization. 1,10-Phenanthroline-5-amine (Aphen) with a donor group-amino was screened out for efficacious photo-controlled radical polymerization under blue light for various monomers with conjugated and unconjugated structures with high monomer conversion and well-defined narrow dispersity polymers (D < 1.20). Controllable homo-polymers and block copolymers were successfully realized by chain extension reaction and block copolymerization of structurally diverse monomers.

Automated summary

Phenanthroline is a stable p-electron acceptor with a large conjugated chromophore and its derivatives are widely used in various applications. Designing efficient organic photocatalysts (OPCs) for reversible-deactivation radical polymerization (RDRP) is still a challenge. In this study, donor-acceptor (D-A) type OPCs based on phenanthroline were used for the first time in photoinduced electron transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization. By combining donor groups and weak acceptor groups, highly controlled polymerization of conjugated and unconjugated monomers was achieved.