Visible Light Catalyzed Oxidative Reactions Using Silver-Based Metal-Organic Frameworks Based on Metalloligands

Photocatalysis plays a crucial role in modern organic synthesis by enabling efficient transformations under mild conditions and reducing the need for harmful reagents. Its ability to harness visible light for sustainable chemical processes makes it an attractive alternative to conventional methods. In this study, we have utilized two silver-based MOFs, incorporating two different Co³⁺-metalloligands, as photocatalysts for oxidation reactions and oxidative coupling processes. The reactions include the oxidation of phenylboronic acids to phenols and the oxidative coupling of amines and anilines to imines and azo compounds. Ag-MOFs demonstrated significant visible light absorption and excellent chemical stability, with superoxide radicals identified as the primary reactive oxygen species. The photocatalytic performance is supported by band gap energy calculation and photophysical studies, including electrochemical impedance, electron paramagnetic resonance, and photoluminescence spectroscopies. The photocatalytic performance of an Ag-MOF was critically influenced by its architecture, including the presence of argentophilic interactions. Such a feature not only enhanced its structural stability but also improved the light absorption, a more significant number of active sites, better charge separation, and a remarkable photocatalytic outcome.