Tetrazine-functionalized hyper-crosslinked polymers for efficient photocatalytic synthesis of benzimidazoles

• Published in: Green chemistry : an international journal and green chemistry resource : GC 2021-02, Vol.23 (3), p.1292-1299
• Main Authors: An, Wan-Kai, Zheng, Shi-Jia, Zhang, Hui-Xing, Shang, Tian-Tian, Wang, He-Rui, Xu, Xiao-Jing, Jin, Qiu, Qin, Yuchen, Ren, Yunlai, Jiang, Song, Xu, Cui-Lian, Hou, Mao-Song, Pan, Zhenliang
• Format: Article
• ISSN: 1463-9262; 1463-9270
• DOI: 10.1039/d0gc03719b

Developing green-safe, efficient and recyclable catalysts is crucial for the chemical industry. So far, organic photocatalysis has been proved to be an environmentally friendly and energy-efficient synthetic technology compared with traditional metal catalysis. As a versatile catalytic platform, hyper-crosslinked polymers (HCPs) with large surface area and high stability are easily prepared. In this report, we successfully constructed two porous HCP photocatalysts (TZ-HCPs) featuring s -tetrazine units and surface areas larger than 700 m 2 g −1 through Friedel-Crafts alkylation reactions. The rational energy-band structures and coexisting micro- and mesopores endow TZ-HCPs with excellent activities to realize the green synthesis of benzimidazoles (28 examples, up to 99% yield, 0.5-4.0 h) in ethanol. Furthermore, at least 21 iterative catalytic runs mediated by TZ-HCP1D were performed efficiently, with 96-99% yield. This study of TZ-HCPs sheds light on the wide-ranging prospects of application of HCPs as metal-free and green photocatalysts for the preparation of fine chemicals. Constructing s -tetrazine-embedded HCP photocatalysts for the green synthesis of benzimidazoles.