By using Schiff base tricarboxylate ligand 5-(4-carboxybenzylideneamino)isophthalic acid (H₃CIP), a new imine functionalized copper metal organic framework (MOF) has been synthesized solvothermally. It was fully characterized by Fourier Transform Infrared (FTIR) Spectroscopy, Powder X-Ray Diffraction (PXRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), and elemental mapping techniques. The as-synthesized MOF has been utilized as fluorescent probe for detection of nitro aromatic explosives (NAEs). The results show that the copper MOF can be developed into highly selective and sensitive sensor for detection of TNP in the aqueous medium via the “turn-off” quenching response. The linear fitting of the Stern-Volmer plot for TNP offered large quenching constant of 1.07 × 10⁴ M⁻¹ for Cu-MOF indicating the high sensitivity of the sensing process. Outstanding sensitivity of prepared material towards TNP detection was further validated by the low detection limit of 80 ppb (0.35 µM). The detailed mechanistic studies for their mode of action and density functional theory (DFT) calculations reveals that photo-induced electron transfer (PET) and fluorescence resonance energy transfer (FRET) processes, as well as electrostatic interactions (i.e. H-bonding) are the key factors for the turn-off response toward TNP by this fluorescent sensor. Thus, this new LMOF owing to their high water stability and remarkable functional features are potential candidates which can be developed into selective and sensitive TNP detection devices.

Graphic Abstract

中文翻译：

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基于席夫碱三羧酸盐配体合成铜金属有机骨架，用于高选择性和高灵敏度检测水性介质中的 2,4,6-三硝基苯酚

通过使用席夫碱三羧酸盐配体 5-(4-羧基亚苄基氨基) 间苯二甲酸 (H ₃ CIP)，溶剂热合成了一种新的亚胺功能化铜金属有机骨架 (MOF)。通过傅里叶变换红外 (FTIR) 光谱、粉末 X 射线衍射 (PXRD)、扫描电子显微镜 (SEM)、能量色散 X 射线光谱 (EDS) 和元素映射技术对其进行了全面表征。合成的 MOF 已被用作检测硝基芳香炸药 (NAE) 的荧光探针。结果表明，铜 MOF 可以开发成高选择性和灵敏的传感器，用于通过“关闭”猝灭响应检测水介质中的 TNP。TNP 的 Stern-Volmer 图的线性拟合提供了 1.07 × 10 的大淬灭常数⁴ M ^-1对于 Cu-MOF 表明传感过程的高灵敏度。80 ppb (0.35 µM) 的低检测限进一步验证了制备材料对 TNP 检测的出色灵敏度。对其作用模式和密度泛函理论 (DFT) 计算的详细机理研究表明，光致电子转移 (PET) 和荧光共振能量转移 (FRET) 过程以及静电相互作用（即H 键合）是该荧光传感器对 TNP 的关闭响应的关键因素。因此，这种新型 LMOF 由于其高水稳定性和显着的功能特性，是可以开发成选择性和灵敏的 TNP 检测装置的潜在候选者。

图形摘要