College of Chemistry, Chemical Engineering and Materials Science, Soochow University, No. 199 Ren'ai Road, Suzhou 215123, Jiangsu, China.
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China.
J Am Chem Soc. 2020 Apr 8;142(14):6690-6697. doi: 10.1021/jacs.0c00368. Epub 2020 Mar 27.
Light-up luminescence sensors have been employed in real-time visual detection of target molecules including volatile organic compounds (VOCs). However, currently employed light-up sensors, which are generally based on the aggregation-induced emission (AIE) or solvent-induced energy transfer effect, exhibit limited sensitivity for light-up detection and poor recycling performances thereby significantly hindering their industrial applications. Inspired by the low-temperature enhanced luminescence phenomenon, we herein propose and show that a guest-lock-induced luminescence enhancement mechanism can be used to realize the ultrafast light-up detection of target VOCs. Through introduction of chlorinated hydrocarbons to lock the molecular vibrations within a designed [CuI]-based metal-organic framework (MOF), luminescence intensity could be enhanced significantly at room temperature. This guest-lock-induced luminescence enhancement is brought about by weak supramolecular interactions between the host framework and the guest molecules, allowing highly sensitive and specific detection of the guest vapor with ultrafast response time (<1 s). Single-crystal X-ray diffraction (SCXRD) analysis of guest molecules-loaded MOFs and density functional theory (DFT) calculations were employed to investigate the host-guest interactions involved in this phenomenon. Moreover, the above MOF sensor successfully achieved real-time detection of a toxic chloroaromatic molecule, chlorobenzene. The guest-lock-induced light-up mechanism opens up a route to discovering high-performance ultrafast light-up luminescent sensors for real-time detection applications.
点亮型荧光传感器已被应用于实时可视化检测目标分子，包括挥发性有机化合物（VOCs）。然而，目前所使用的点亮型传感器，通常基于聚集诱导发光（AIE）或溶剂诱导能量转移效应，其对点亮检测的灵敏度有限，且循环性能较差，这严重限制了它们的工业应用。受低温增强发光现象的启发，我们提出并展示了一种客体锁致发光增强机制，可用于实现对目标 VOC 的超快点亮检测。通过引入氯化烃来锁定设计的基于[CuI]的金属有机骨架（MOF）内的分子振动，可以在室温下显著增强发光强度。这种客体锁致发光增强是由主体骨架与客体分子之间的弱超分子相互作用引起的，允许对客体蒸气进行高灵敏度和特异性的检测，响应时间超快（<1 s）。客体负载 MOF 的单晶 X 射线衍射（SCXRD）分析和密度泛函理论（DFT）计算被用于研究该现象中涉及的主客体相互作用。此外，上述 MOF 传感器成功实现了对有毒氯代芳烃分子氯苯的实时检测。客体锁致点亮机制为发现用于实时检测应用的高性能超快点亮荧光传感器开辟了一条途径。
