D-A Conjugated Organic Polymers as Nonhomogeneous Photocatalysts for PET-RAFT Polymerization

D-A conjugated organic polymer (COP) photocatalystsarea very promising photocatalytic material because of their tunablestructure at the molecular level and diverse species. D-A conjugatedorganic polymers composed of relatively weak donor units and strongacceptor units are more favorable for photogenerated charge migrationand thus exhibit better photocatalytic activity. Herein, a seriesof D-A conjugated organic polymers were constructed by introducingCN-absorbing groups to the benzene ring using 1,3,5-triethynylbenzeneas the donor unit and the benzene ring as the acceptor unit to catalyzethe reversible addition-fragmentation chain transfer (RAFT)polymerization of methyl methacrylate under white light irradiation,and the resulting polymers had controlled molecular weight and narrowmolecular weight distribution. The effect of increasing the numberof CN groups on the photogenerated charge migration ability of thecatalyst and the RAFT polymerization rate was investigated by bothexperiments and theoretical calculation to reveal the conformationalrelationship between the polymer structure and the photocatalyticRAFT polymerization rate. It is proved that D-A conjugatedorganic polymers composed of relatively weak donor units and strongacceptor units are more favorable for photogenerated charge migrationand thus exhibit better photocatalytic activity.