Structural Regulation of Three-Dimensional Covalent Organic Frameworks for Efficient Photoredox Catalysis toward Atom Transfer Radical Polymerization

Abstract

Covalent organic frameworks (COFs) have emerged as a thriving class of photocatalysts in various chemical transformations. However, the utilization of COFs as photoredox catalysts for atom transfer radical polymerization is rarely known. Herein, we designed and synthesized a series of phenazine-based functional 3D COFs with the dia topology. Structural regulation over interpenetration folds and energy levels of COFs was implemented through the substituent effects. These COFs can work as effective photoredox catalysts toward atom transfer radical polymerization. Notably, the COF with trifluoromethyl substituent groups exhibits much higher catalytic activity than other COFs, allowing the efficient synthesis of polymers with controllable molecular weights, low dispersity, and high conversion. Notably, it constitutes the most efficient one among all the metal-free photocatalysts. This work not merely realizes the structural regulation of 3D COFs through substituent effects, but also exhibits brilliant prospects for the utilization of COFs as efficient catalysts in a bunch of challenging chemical transformations.