Benzodiazole-Based Covalent Organic Frameworks for Enhanced Photocatalytic Dehalogenation of Phenacyl Bromide Derivatives

Covalent organic frameworks (COFs) have garnered significant interest within the scientific community due to their distinctive ability to act as organic semiconductors responsive to visible light. This unique attribute makes them up-and-coming candidates for facilitating photocatalytic organic reactions. Herein, two donor-acceptor COFs, TPE-BSD-COF and TPE-BD-COF, have been designed and synthesized by incorporating electron-rich tetraphenylethylene and electron-deficient benzoselenadiazole and benzothiadiazole units into the framework through a Schiff-base polycondensation reaction. Both COFs exhibit exceptional crystallinity and enduring porosity. TPE-BSD-COF and TPE-BD-COF exhibit broad light absorption capabilities, a narrow optical band gap, and low electrochemical impedance spectrum (EIS) levels, indicating that the two COFs are effective heterogeneous photocatalysts for the reductive dehalogenation of phenacyl bromide derivatives under blue LED irradiation. A high photocatalytic yield of 98% and 95% was achieved by TPE-BSD-COF and TPE-BD-COF catalysts, respectively, within only one hour.