Organic molecular sieve adorned with s-tetrazine: an efficient platform for gram-scale organic photoredox catalysis

Abstract

The chemical industry in the emerging era requires efficient and stable porous catalysis technology. In this context, porous photocatalysis has emerged as a recycled and energy-efficient synthetic strategy in accordance with the fundamental principles of clean chemistry. Organic molecular sieve (OMS) catalysts, known for their easily adjustable structures and exceptional properties, can serve as potential platforms aimming at the production of fine chemicals. The report showcases a concise synthesis of TZ-OMS photocatalyst with s-tetrazine via FeCl3 catalyzed Friedel-Crafts reaction, combined with the salts-modulated strategy to enhance its surface areas (694-900 m2g-1). TZ-OMS significantly facilitated the concise synthesis of benzimidazoles at gram-scale (upto 99% yield) in both batch and flow reactions using EtOH under air and light conditions. Notably, the continuous flow photocatalysis here fulfills the requirements of green chemistry through its simplified design, high efficiency and reusability. Moreover, TZ-OMS demonstrated exceptional recyclability with 13/24 iterative runs for 5 mmol/0.2 mmol scale and remarkable stability. The findings provide insights into the practical approach for the efficient and large-scale production of fine chemicals using OMS photocatalysts