Phenolic Resin\nwith an Optimized Donor–Acceptor\nArchitecture for Photocatalytic Aerobic Oxidation

A promising\nstrategy to enhance exciton dissociation\nand charge\nseparation in phenolic-polymer-based photocatalysts is the generation\nand utilization of benzenoid–quinoid donor–acceptor\n(D–A) couples inside the phenolic resin frameworks. However,\nthere are often more donors than acceptors in phenolic resin due to\nthe sluggish kinetics of in situ oxidation of phenols to quinoid methides,\nleading to a mismatched D/A ratio. Herein, we report a well-cross-linked\nphenolic resin with a unity D/A ratio synthesized by using phloroglucinol\nas a building block for condensation with formaldehyde. The higher\nelectron density on the aromatic ring not only facilitates the in\nsitu oxidation of phloroglucinols to quinoid methides, forming equivalent\nD–A couples, but also lowers the energy barrier for the condensation\nreaction, resulting in a highly cross-linked framework with a well-developed\nπ-conjugated electronic structure. The phloroglucinol-formaldehyde\nresin product demonstrates significantly improved photocatalytic performance\nin the selective oxidation of methyl phenyl sulfide and the oxidative\ncoupling of benzylamine. Our approach shows the potential of photocatalytic\nphenolic resins for solar-induced chemical conversion.