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

Visible-light-driven organic transformations, such asphotocatalyticreductive dehalogenation, are highly significant but remain challengingto implement because of the insufficient charge separation. Herein,we report a facile strategy to realize heterogeneous and high-efficiencyphotocatalytic dehalogenation under mild conditions via tuning theexciton binding energy of conjugated microporous polymers (CMPs) withan alternating electron donor (D)-acceptor (A) structural motif.The integration of acceptors, especially strong ones (sA), into theconjugated polymer scaffolds minimized the exciton binding energy,suppressed charge carrier recombination, and facilitated the chargetransfer effectively. CMP-CSU11, featuring an alternative D-sAskeleton with the lowest exciton binding energy, exhibited a superiorphotocatalytic 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 possessingextraordinary recyclability. This work provides an effective strategybased on intramolecular charge transfer engineering to develop heterogeneousphotocatalysts for task-specific organic transformation.