Visible-light-active benzothiadiazole-based MOFs as efficient ROS generators for the synthesis of benzimidazoles and benzothiazoles

Abstract

The utilization of reactive oxygen species (ROS) in photochemical synthesis has garnered significant attention owing to their exceptional oxidative capacity under mild conditions. Recently, metal–organic frameworks (MOFs) have been employed to convert molecular oxygen (O₂) to ROS for photocatalysis. However, visible-light-active MOFs for effective oxygen activation remain scarce. Herein, a simple and effective strategy, linker functionalization, is utilized to immobilize the benzothiadiazole unit inside the UiO-68-type MOF (UiO-68-BTDB). The MOF was applied as the first example generating superoxide radical anions (O₂˙⁻) and singlet oxygen (¹O₂) for access to benzimidazoles and benzothiazoles in air at room temperature. Recycling experiments were performed to confirm the stability and reusability of UiO-68-BTDB as a robust heterogeneous catalyst.