Copper(I)-Based Coordination Polymers for Photocatalytic Benzylic C(sp3)-H-Oxidation via Energy Transfer.

Abstract

The selective oxidation of benzylic C(sp³)-H bonds with a high bond dissociation energy (BDE) remains challenging. Copper-based metal-organic coordination polymers are promising mimics of Cu enzymes but suffer from limited selectivity. Herein, two Cu-based coordination polymers with precisely tuned coordination environments are synthesized to emulate enzymatic benzylic oxidation. Their unique hexagonal structures enhance substrate adsorption and energy transfer (EnT). Under visible light, the coordination polymers exhibit prolonged fluorescence lifetimes and high-energy excited states, enabling efficient oxygen activation via energy transfer. The optimized Cu-pbhc framework interacts with hydroquinone (HQ) to demonstrate selective benzylic oxidation, achieving an 84% yield with over 90% selectivity toward a toluene derivative. This study proposes a systematic design strategy for developing high-performance catalysts for benzylic oxidation, achieved through the synergistic regulation of redox properties and excited-state dynamics.