Metal Polyphenol Network Enables Photo-ATRP Under Blue Light.

Photo-ATRP commonly relies on petrochemical-derived ligands and copper-based catalytic systems, which is misaligned with green-chemistry principles. Here, 4-hydroxychalcone is used as a building block and functionalized amino groups through a Mannich reaction, then self-assembled with FeBr3 to form a metal-polyphenol network (MPN). Under 420 nm visible-light irradiation, the MPN effectively mediates photo-ATRP, reaching a maximum monomer conversion of 67.4%. The resulting polymers exhibit a dispersity of Đ < 1.5, with values down to 1.3, indicating a certain control of polymerization. Using the PMMA-Br macroinitiator, synthesis of block copolymers comprising methyl methacrylate (MMA), benzyl methacrylate (BMA), and styrene (St) successfully succeeded. Notably, polymers exhibiting a dispersity of Đ < 1.5 were obtained even without degassing, while chain-end fidelity was available. In addition, a FeCl3-catalyzed photo-ATRP system is demonstrated. Overall, this work provides an operationally simple approach to light-controlled radical polymerization using Fe catalysts with bio-based ligands.