School of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, Zhejiang, China.
Department of Haematology, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, School of Medicine of University of Electronic Science and Technology of China, Chengdu 610000, China.
Anal Chem. 2023 Apr 25;95(16):6612-6619. doi: 10.1021/acs.analchem.2c05629. Epub 2023 Apr 12.
The reporter-spacer-receptor (RSR) approach is prevalent to develop molecular turn-on sensors. However, the fluorescent RSR sensors barely operate in solid state, which hinders their fabrication into devices for practical applications. Herein, we present a novel strategy to achieve solid-state luminescence turn-on sensing by assembling RSR architectures within MOF frameworks. Unlike the regular RSR systems, the framework-confined fluorophore and receptor are well arranged and separated even in the solid state. This concept is illustrated by a multicomponent MOF (Fc@NU-1000), which contains organic linkers with a highly luminescent pyrene core as the reporter, Zr nodes with unsaturated sites as the receptor, and the incorporated Fc molecules as the quencher. The separate incorporation of pyrene core and Fc in the multicomponent MOF favors an efficient pseudointramolecular photoinduced electron transfer (PET) process, resulting in significant luminescence quenching. Interestingly, such PET process can be blocked via the quencher displacement initiated by the phosphate analyte, therefore recovering the solid-state luminescence of MOF microcrystals. We found that Fc@NU-1000 is shown as a sensitive solid-state luminescence turn-on probe for phosphate with the naked-eye response at a low content. What's more, this study is the first example of confining a quencher displacement-based RSR system in the MOF framework for solid-state luminescence turn-on sensing, thus also providing new opportunities for MOF materials to develop luminescence turn-on sensors.
记者-间隔物-受体（RSR）方法常用于开发分子开启型传感器。然而，荧光 RSR 传感器在固态下几乎无法工作，这阻碍了它们被制成用于实际应用的器件。在此，我们提出了一种通过将 RSR 结构组装在 MOF 框架内来实现固态发光开启传感的新策略。与常规 RSR 系统不同，即使在固态下，框架限制的荧光团和受体也能得到很好的排列和分离。这一概念通过一个多组分 MOF（Fc@NU-1000）得到了说明，其中包含具有高发光芘核心的有机连接体作为报告基团、具有不饱和位点的 Zr 节点作为受体，以及掺入的 Fc 分子作为猝灭剂。芘核心和 Fc 在多组分 MOF 中的单独掺入有利于有效的假分子光诱导电子转移（PET）过程，从而导致显著的荧光猝灭。有趣的是，这种 PET 过程可以通过磷分析物引发的猝灭剂置换来阻断，从而恢复 MOF 微晶的固态发光。我们发现，Fc@NU-1000 表现出对磷酸盐的灵敏固态发光开启探针，在低含量下具有肉眼可见的响应。更重要的是，这项研究是首例将基于猝灭剂置换的 RSR 系统限制在 MOF 框架内用于固态发光开启传感的例子，从而也为 MOF 材料开发发光开启传感器提供了新的机会。
