Metal-free g-C 3 N 4 nanosheets as a highly visible-light-active photocatalyst for thiol-ene reactions

• Published in: Nanoscale 2021-02, Vol.13 (6), p.3493-3499
• Main Authors: Zhang, Shouren, Yi, Wenjing, Guo, Yanzhen, Ai, Ruoqi, Yuan, Zhichao, Yang, Baocheng, Wang, Jianfang
• Format: Article
• Language: English
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/D1NR00453K

Thiol-ene click reactions are important for the construction of carbon-sulfur bonds. The use of visible-light photoredox catalysis for the formation of C-S bonds has attracted much attention. In this work, two-dimensional metal-free graphitic carbon nitride (g-C N ) nanosheets are prepared through a simple thermal polymerization method and used to catalyze the thiol-ene click reaction under visible light-illumination. This green, atom-economic, and inexpensive approach for the hydrothiolation of alkenes is applicable for structurally different substrates and exhibits superior yields. In air or nitrogen atmosphere, the reaction yield decreases when a hole scavenging agent, CH OH, is introduced, which indicates that photogenerated holes in the g-C N nanosheets play an important role in the formation of thiyl radicals. The g-C N nanosheets still show a good stability and favorable photocatalytic activity after five cycles of the reaction. Moreover, this approach can be scaled up to the gram-scale synthesis of benzyl(phenethyl)sulfane with a yield up to 93%. Our study suggests a good potential of semiconducting g-C N nanosheets as a metal-free, efficient photocatalyst for various thiol-ene click reactions and even for other organic reactions.