The acidic-free synthesis of 2-nitropyrrole and 2,5-dinitropyrrole using choline nitrate as regent and Pd@C3N4 as photocatalyst

• Published in: Journal of photochemistry and photobiology. A, Chemistry. Vol. 456; p. 115796
• Main Authors: Li, Yanle, Liang, Dong, Zhu, Taisheng, Zhou, Yumiao, Zheng, Rushui, Zhu, Na, Li, Yongxiang, Cao, Duanlin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2024
• Subjects: Carbon nitride; Chlorate; Nitration; Palladium; Photocatalysis; Pyrrole; Nitration; Palladium; Chlorate; Photocatalysis; Pyrrole; Carbon nitride
• ISSN: 1010-6030; 1873-2666
• DOI: 10.1016/j.jphotochem.2024.115796

[Display omitted] •2-Nitro and 2,4-dinitro pyrroles can be achieved via a green acidic-free process.•Choline nitrate firstly served as a reagent for the photocatalytic nitration.•Photoinduced electrons and palladium NPs took pivotal roles during that.•Shifts of cyclic voltammetry uncovered photochemical transformation of nitrates. Escaping from conventional hazardous methods, an innovative, acidic-free approach for the synthesis of nitro-heterocycles was realized through photocatalytic nitration using Pd-doped g-C3N4. In this method, chlorate nitrate was initially utilized as a reagent. Spectral analysis and electronic microscopy confirmed the successful doping of Pd nanoparticles (NPs) onto the g-C3N4 surface, which subsequently enhanced the photocatalytic performance. The photogenerated electrons and Pd NPs played pivotal roles in the production of nitro-products. The reactive intermediate, NO2+, derived from nitrate, can be captured and elucidated through the shifts in cyclic voltammetry (CV) curves. Herein, the synthesis of 2-nitropyrrole and 2,5-dinitropyrrole was achieved through the nitration of chlorate nitrate in a friendly manner. Moreover, the composite photocatalyst could be readily isolated and recycled in next four tests, demonstrating its practicality and sustainability in photocatalytic applications.