Donor–π–acceptor conjugated microporous polymers for photocatalytic organic conversion with photogenerated carrier separation ability by an embedded electric field along the molecular chain

• Published in: Applied catalysis. A, General General, 2024-02, Vol.671, p.119576, Article 119576
• Main Authors: Wang, Dongdong, Wang, Bowei, Pang, Yiying, Gou, Yu, Zhu, Hongqi, Chen, Ligong
• Format: Article
• Language: English
• Subjects: Benzimidazole; Built-in electric field; Conjugated microporous polymer; Photocatalysis
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/j.apcata.2024.119576

Photogenerated electron-hole pairs in conjugated microporous polymers (CMPs) recombine easily, thus donor-acceptor (D-A) structure was reported to promote the separation of photogenerated carriers, while the inevitable relationship behind them has not been established. Herein, a series of D–π–A type CMPs (Dz-B-CMP, Pz-B-CMP, and Py-B-CMP) were designed and constructed from carbazole (donor) and six-membered nitrogenous ring (acceptor). The photocatalytic performance of the prepared CMPs was evaluated in the reaction between o-phenylenediamine and benzaldehyde. Satisfactorily, Py-B-CMP exhibited the excellent photocatalytic activity with benzimidazole yield of 95.5%, and a wide range of substrate adaptability and outstanding recycling stability. Further theoretical calculations demonstrated that the excellent activity of Py-B-CMP was attributed to the built-in electric field along the molecular chain. This endowed Py-B-CMP with a powerful driving force for the separation and migration of photogenerated carriers, resulting in a remarkable photocatalytic performance. Additionally, a possible photocatalytic synthesis mechanism of benzimidazole was proposed. [Display omitted] •Three carbazole-CMPs, namely Dz-B-CMP, Pz-B-CMP and Py-B-CMP, are fabricated.•Exhibited excellent photocatalytic performance and recyclability in benzimidazole synthesis reaction.•A possible synthesis mechanism of benzimidazole was speculated.•Built-in electric field along the molecular chain promotes the separation and migration of photogenerated carriers.