State Key Laboratory of Coordination Chemistry, Nanjing University , Nanjing 210093, P. R. China.
ACS Appl Mater Interfaces. 2018 Jan 31;10(4):3801-3809. doi: 10.1021/acsami.7b17762. Epub 2018 Jan 19.
A hydroxyl-functionalized ligand was designed for the construction of metal-organic framework (MOF) materials with the aggregation-induced emission (AIE) feature, in which the fluorescence can be deliberately tailored: quenching the fluorescence to an "off" state by the decoration with heterocyclic auxiliary ligand 4,4'-bypyridine (Bpy) in the framework as a quenching agent and triggering the enhanced fluorescence to an "on" state by removal of Bpy through the metal competitive coordination substitution strategy. Our study shows that the occurrence of exciton migration between the AIE linker and conjugated auxiliary ligand Bpy causes fluorescence quenching. Time-dependent density functional theory was employed to understand the photoinduced electron transfer process and explain the origins of fluorescence quenching. Using this strategy, the prepared MOF material can perform as a fluorescence "off-on" probe for highly sensitive detection of Al in aqueous media. The hydroxyl group plays a crucial role in sensing as it can selectively chelate Al, which is directly related to the dissociation of nonfluorescent MOF and consequent activation of the AIE process.
设计了一种带有羟基官能团的配体，用于构建具有聚集诱导发射（AIE）特性的金属有机骨架（MOF）材料，可对其荧光进行有针对性的调节：通过在骨架中用杂环辅助配体 4,4'-联吡啶（Bpy）进行修饰，将荧光猝灭至“关”态，作为猝灭剂，通过金属竞争性配位取代策略除去 Bpy，触发增强的荧光至“开”态。我们的研究表明，AIE 连接体和共轭辅助配体 Bpy 之间的激子迁移导致荧光猝灭。采用含时密度泛函理论来理解光诱导电子转移过程，并解释荧光猝灭的原因。利用这种策略，制备的 MOF 材料可用作荧光“关-开”探针，用于水中 Al 的高灵敏度检测。羟基在传感中起着至关重要的作用，因为它可以选择性螯合 Al，这与非荧光 MOF 的解离直接相关，并因此激活 AIE 过程。
