Enhanced Reducibility via Altering Exciton Binding Energy of Conjugated Microporous Polymers for Photocatalytic Reduction

Abstract

Visible-light-driven organic transformations, such as photocatalytic reductive dehalogenation, are highly significant but remain challenging to implement because of the insufficient charge separation. Herein, we report a facile strategy to realize heterogeneous and high-efficiency photocatalytic dehalogenation under mild conditions via tuning the exciton binding energy of conjugated microporous polymers (CMPs) with an alternating electron donor (D)–acceptor (A) structural motif. The integration of acceptors, especially strong ones (sA), into the conjugated polymer scaffolds minimized the exciton binding energy, suppressed charge carrier recombination, and facilitated the charge transfer effectively. CMP-CSU11, featuring an alternative D–sA skeleton with the lowest exciton binding energy, exhibited a superior photocatalytic dehalogenation efficiency over 99% in only 50 min, surpassing the state-of-the-art photoreductive dehalogenation catalysts, enabling a broad scope of substrates (14 examples), and possessing extraordinary recyclability. This work provides an effective strategy based on intramolecular charge transfer engineering to develop heterogeneous photocatalysts for task-specific organic transformation.