Unusual light-driven amplification through unexpected regioselective photogeneration of five-membered azaheterocyclic AIEgen

作者：Li, Qiyao; Gong, Junyi; Li, Ying; Zhang, Ruoyao; Wang, Haoran; Zhang, Jianquan; Yan, He; Lam, Jacky W. Y.; Sung, Herman H. Y.; Williams, Ian D.; Kwok, Ryan T. K.; Li, Min-Hui; Wang, Jianguo^*; Tang, Ben Zhong^*

来源：Chemical Science, 2021, 12(2): 709-717.

DOI：10.1039/d0sc04725b

• AGGREGATION-INDUCED EMISSION
• CROSS-CYCLOADDITION
• HIGHLY EFFICIENT
• SCHOLL REACTION
• LUMINOGENS
• FLUORESCENCE
• DESIGN
• NANOPARTICLES
• CARBAZOLES
• ANNULATION

Developing versatile synthetic methodologies with merits of simplicity, efficiency, and environment friendliness for five-membered heterocycles is of incredible importance to pharmaceutical and material science, as well as a huge challenge to synthetic chemistry. Herein, an unexpected regioselective photoreaction to construct a fused five-membered azaheterocycle with an aggregation-induced emission (AIE) characteristic is developed under mild conditions. The formation of the five-membered ring is both thermodynamically and kinetically favored, as justified by theoretical calculation and experimental evidence. Markedly, a light-driven amplification strategy is proposed and applied in selective mitochondria-targeted cancer cell recognition and fluorescent photopattern fabrication with improved resolution. The work not only delivers the first report on efficiently generating a fused five-membered azaheterocyclic AIE luminogen under mild conditions via photoreaction, but also offers deep insight into the essence of the photosynthesis of fused five-membered azaheterocyclic compounds.