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

Phenanthroline is an excellent and stableπ-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(Đ<1.20).Controllable homo-polymers and block copolymers were successfully realized by chain extension reaction and block copolymerization of structurally diverse monomers.