Xiong Jia-Bin, Feng Hai-Tao, Wang Jin-Hua, Zhang Chun, Li Bao, Zheng Yan-Song
Key Laboratory for Chemistry of Energy Conversion and Storage Materials, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P.R. China.
College of Life Science and Technology, Huazhong University of, Science and Technology, Wuhan, 430074, P.R. China.
Chemistry. 2018 Feb 6;24(8):2004-2012. doi: 10.1002/chem.201705346. Epub 2018 Jan 16.
Tetraphenylethylene (TPE) foldamers with double hairpin-turn linkers showing an aggregation-induced emission (AIE) effect have been synthesized for the first time. A crystal structure of a foldamer-TNT complex has been obtained, enabling unprecedented direct observation of the interactions between TNT molecules and the chromophores of the foldamer. Instead of π-π stacking interactions, which have often been considered to be the key mechanism in the binding of TNT by chromophoric receptors, strong n-π interactions between the nitro groups of TNT and the aromatic rings of the foldamer have been found. Exceptionally, by addition of 1 % NaF to a suspension of the foldamer in H O/THF (95:5), the fluorescence quenching efficiency by TNT vapor significantly increased from about 20 % to more than 90 %. Even after diluting TNT-saturated air at 25 °C by a factor of 2×10 , an obvious quenching response was observed, indicating that ultratrace TNT vapor (down to 3.4 fg per mL of air) could be detected.
首次合成了具有双发夹转折连接基且呈现聚集诱导发光（AIE）效应的四苯乙烯（TPE）折叠体。已获得折叠体 - TNT配合物的晶体结构，从而能够对TNT分子与折叠体发色团之间的相互作用进行前所未有的直接观察。已发现，与通常被认为是发色团受体结合TNT的关键机制的π - π堆积相互作用不同，TNT的硝基与折叠体的芳环之间存在强烈的n - π相互作用。特别地，通过向折叠体在H₂O/THF（95:5）中的悬浮液中加入1%的NaF，TNT蒸气的荧光猝灭效率从约20%显著提高到90%以上。即使在25°C下将TNT饱和空气稀释2×10倍后，仍观察到明显的猝灭响应，表明可以检测到超痕量的TNT蒸气（低至每毫升空气3.4 fg）。
