Insights into the Fluorescence Sensing Mechanism of Scandium-Based Metal-Organic Frameworks by Solid-State NMR Spectroscopy
Insights into the Fluorescence Sensing Mechanism of Scandium-Based Metal-Organic Frameworks by Solid-State NMR Spectroscopy
复制标题
通过固态核磁共振波谱深入了解钪基金属有机框架的荧光传感机制
DOI：
10.1002/slct.201900821
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发表时间：
2019
期刊：
影响因子：
2.1
通讯作者：
Liu Jinhuai
中科院分区：
文献类型：
--
作者：
Xie Chang;Yu Zhiwu;Tong Wei;Shehzad Khurram;Xu Weihong;Wang Junfeng;Liu Jinhuai
荧光金属有机框架（MOF）已发展成为一类有前景的传感应用材料。然而，从分子水平理解发光MOFs与分析物物种相互作用的传感机制仍然是一个具有挑战性的问题。在此，制备荧光 Sc2(NH2-BDC)3 晶体作为探针。系统地表征了所得产物的组成和结构特征。 Sc2(NH2-BDC)3在不同溶剂和不同pH值的水溶液中表现出优异的热稳定性和化学稳定性。通过荧光猝灭效应，它对 Co2+ 和 Ni2+ 离子表现出优异的荧光传感行为。通过X射线光电子能谱（XPS）分析、傅里叶变换红外（FTIR）光谱分析、固态核磁共振（ssNMR）谱和电子顺磁共振（EPR）分析阐明了Sc2（NH2-BDC）3对重金属离子的传感机制。 ssNMR和EPR分析表明，所制备的Sc2(NH2-BDC)3晶体含有一些缺陷，晶体结构中形成钪羟基，这些缺陷易于与Co2+和Ni2+离子相互作用，导致荧光猝灭。该研究不仅从分子水平阐述了对发光MOFs传感机制的理解，而且突出了用于荧光传感的功能化MOFs的设计。
Fluorescent metal‐organic frameworks (MOFs) have been evolved as a class of promising materials for sensing application. However, it is still a challenging issue to understand the sensing mechanism of luminescent MOFs interacting with analyte species from molecule level. Herein, fluorescent Sc2(NH2‐BDC)3crystals are prepared as a probe. The compositional and structural characteristics of the obtained product are systematically characterized. Sc2(NH2‐BDC)3shows admirable thermal and chemical stability in different solvents and aqueous solutions with diverse pH values. It shows excellent fluorescence sensing behaviors towards Co2+and Ni2+ions through fluorescence quenching effect. The sensing mechanism of Sc2(NH2‐BDC)3towards heavy metal ions is elucidated via X‐ray photoelectron spectroscopy (XPS) analyses, Fourier transform infrared (FTIR) spectroscopy analyses, solid‐state NMR (ssNMR) spectra and electron paramagnetic resonance (EPR) analyses. The as‐prepared Sc2(NH2‐BDC)3crystals contain some defects with formation of scandium hydroxyls in the crystal structure from the evidence analyzed by ssNMR and EPR, which are inclined to interact with Co2+and Ni2+ions, leading to the fluorescent quenching. This research not only demonstrates the understanding of the sensing mechanism of luminescent MOFs from molecular level, but also highlights the design of functionalized MOFs for fluorescent sensing.