School of Chemistry & Chemical Engineering, Key Laboratory of Macromolecular Science of Shaanxi Province, Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education , Shaanxi Normal University , Xi'an , Shaanxi 710062 , P. R. China.
ACS Appl Mater Interfaces. 2019 Mar 27;11(12):11338-11348. doi: 10.1021/acsami.8b20410. Epub 2019 Mar 13.
The concept of high-performance excited-state intramolecular proton transfer (ESIPT)-based fluorescent metal-organic framework (MOF) probes for Al is proposed in this work. By regulating the hydroxyl groups on the organic linker step by step, new fluorescent magnesium-organic framework (Mg-MOF) probes for Al ions were established based on the ESIPT fluorescence mechanism. It is observed for the first time that the number of intramolecular hydrogen bonds between adjacent hydroxyl and carboxyl groups can effectively adjust the ESIPT process and lead to tunable fluorescence sensing performance. Together with the well-designed porous and anionic framework, the Mg-TPP-DHBDC probe decorating with a pair of intramolecular hydrogen bonds exhibits extra-high quantitative fluorescence response to Al through an unusual turn-off (0-1.2 μM) and turn-on (4.2-15 μM) luminescence sensing mechanism. Notably, the 28 nM limit of detection value represents the lowest record among all reported MOF-based Al fluorescent sensors up to now. Benefited from the unique turn-off-on ESIPT fluorescence detection process, the Mg-TPP-DHBDC MOF sensor exhibits single Al detection compared with other 16 common metal ions including Ga, In, Fe, Cr, Ca, and Mg. Impressively, such an Al selective sensing process can even be fulfilled by the reusable MOF test paper detected by naked eyes. Overall, the quantitative Al detection, together with the extraordinary sensitivity, selectivity, fast response, and good reusability, strongly supports our concept of ESIPT-based fluorescent MOF Al probes and makes Mg-TPP-DHBDC one of the most powerful Al fluorescent sensors.
本工作提出了一种基于高效激发态分子内质子转移（ESIPT）的荧光金属-有机骨架（MOF）探针用于检测 Al 的概念。通过逐步调节有机配体上的羟基，我们基于 ESIPT 荧光机制建立了新型荧光镁-有机骨架（Mg-MOF）探针用于 Al 离子的检测。我们首次观察到，相邻羟基和羧基之间的分子内氢键数量可以有效地调节 ESIPT 过程，并导致可调谐的荧光传感性能。结合精心设计的多孔和阴离子骨架，Mg-TPP-DHBDC 探针上一对分子内氢键的存在使其对 Al 表现出额外的高定量荧光响应，通过一种不寻常的关闭（0-1.2 μM）和开启（4.2-15 μM）的发光传感机制。值得注意的是，28 nM 的检测限代表了迄今为止所有报道的基于 MOF 的 Al 荧光传感器中的最低记录。得益于独特的关闭-开启 ESIPT 荧光检测过程，Mg-TPP-DHBDC MOF 传感器与其他 16 种常见金属离子（包括 Ga、In、Fe、Cr、Ca 和 Mg）相比，对单个 Al 进行检测。令人印象深刻的是，这种 Al 选择性传感过程甚至可以通过肉眼检测的可重复使用的 MOF 试纸来实现。总体而言，定量 Al 检测以及非凡的灵敏度、选择性、快速响应和良好的可重复性，有力地支持了基于 ESIPT 的荧光 MOF Al 探针的概念，并使 Mg-TPP-DHBDC 成为最强大的 Al 荧光传感器之一。
