Construction of Heteroleptic Copper Complexes in Perylene Diimide-Based COFs for Heterogeneous Metallaphotoredox Catalysis

Despite recent advances in developing diimine-containing copper photocatalysts for organic synthesis, further exploration of heteroleptic phenanthroline-ligated copper complexes remains challenging due to rapid ligand exchange in homogeneous solutions. Herein, we employ a framework-based heterogenization strategy to successfully synthesize such previously inaccessible copper complexes through postsynthetic modification. By integrating photoactive perylene diimide units into a one-dimensional covalent organic framework, the visible-light-driven oxo-azidation of styrenes can be accomplished with substantially reduced copper loadings in metallaphotoredox catalysis. Notably, our newly developed heterogeneous photocatalytic platform demonstrates that the reactive copper species facilitates the ketone formation step in the oxo-azidation without dissociation of one of the phenanthroline ligands. These findings highlight the potential of well-defined framework materials to address fundamental challenges in the synthesis of transition-metal complexes and enable detailed mechanistic studies that complement traditional homogeneous catalysis.