Direct identification of HMX via guest-induced fluorescence turn-on of molecular cage

作     者：Chen Wang Jin Shang Li Tian Hongwei Zhao Peng Wang Kai Feng Guokang He Jefferson Zhe Liu Wei Zhu Guangtao Li Chen Wang;Jin Shang;Li Tian;Hongwei Zhao;Peng Wang;Kai Feng;Guokang He;Jefferson Zhe Liu;Wei Zhu;Guangtao Li

作者机构：Department of ChemistryTsinghua UniversityBeijing 100084China School of Energy and EnvironmentCity University of Hong KongHong KongChina Department of Mechanical EngineeringThe University of MelbourneParkvilleVIC 3010Australia School of Biology and Biological EngineeringSouth China University of TechnologyGuangzhou 510006China Institute of chemistryHebrew University of JerusalemJerusalem 91904Israel 

出 版 物：《Chinese Chemical Letters》 (中国化学快报（英文版）)

年 卷 期：2021年第32卷第12期

页      面：4006-4010页

核心收录：

学科分类：082604[工学-军事化学与烟火技术] 08[工学] 0826[工学-兵器科学与技术] 

基　　金：the National Natural Science Foundation of China (NSFC, Nos. 21773135, 22032003, 21821001) the Ministry of Science and Technology (MOST, No. 2017YFA0204501) the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation, No. TRR61) 

主　　题：Chemical sensing Explosive detection HMX Molecular cage Host-guest chemistry Fluorescence turn-on 

摘      要：Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine(HMX) is one of the most widely used powerful explosives. The direct and selective detection of HMX, without the requirement of specialized equipment, remains a great challenge due to its extremely low volatility, unfavorable reduction potential and lack of aromatic rings. Here, we report the first chemical probe of direct identification of HMX at ppb sensitivity based on a designed metal-organic cage(MOC). The cage features two unsaturated dicopper units and four electron donating amino groups inside the cavity, providing multiple binding sites to selectively enhance host-guest events. It was found that compared to other explosive molecules the capture of HMX inside the cavity would strongly modulate the emissive behavior of the host cage, resulting in highly induced fluorescence “turn-on(160 folds). Based on the density functional theory(DFT) simulation, the mutual fit of both size and binding sites between host and guest leads to the synergistic effects that perturb the ligand-to-metal charge-transfer(LMCT) process, which is probably the origin of such selective HMX-induced turn-on behavior.