Mechanochemical Construction of Benzimidazole-Bridged Conjugated Porous Polymer Toward Versatile Photocatalysis

Conjugated porous polymers (CPPs) have found rapidly expanding applications in a wide range of research areas. However, most of the reported CPPs are constructed through thermochemistry, which often requires transition metals or harsh reaction conditions. Here we report a highly efficient and environmentally friendly mechanochemical approach to synthesize benzimidazole-bridged conjugated porous polymer (TX-BI-POP) via a ring-formation strategy. More importantly, the resultant TX-BI-POP exhibits excellent photocatalytic performance and can be applied as a rare versatile metal-free and reusable photocatalyst. Specifically, the synthetic utility of TX-BI-POP has been illustrated in three types of mechanistically distinct prototypic organic transformations: net oxidative hydroxylation of arylboronic acids, redox neutral bromoalkylation of unactivated terminal alkenes, and net reductive pinacol C–C coupling. This work not only provides a green and sustainable way to access porous materials but also opens a new class of versatile metal-free heterogeneous photocatalysts for organic transformations.