Abstract An oxadiazole-based chemosensor (sensor 1) for Fe3+/Fe2+ was successfully designed and synthesized. Sensor 1 displayed fluorescence quenching response towards both Fe3+ and Fe2+ in THF:H2O (4:1, v/v) solvent with high selectivity and sensitivity over all other competitive metal ions. Job's plot, mass spectra, DFT calculation and fluorescence titration disclosed that fluorescence quenching was caused by forming 1:1 complex between sensor 1 and iron ions. Sensor 1 presented high sensitive fluorescence response at the pH value of human body and its fluorescence intensity showed linear relationship with the concentration of iron ion. Sensor 1 also presented fast fluorescence response towards iron ions and the lower detection limit, 7.78 μM for Fe2+ ion and 6.95 μM for Fe3+ ion, respectively. Sensor 1 can be used as test strips to detect iron ions in water samples. Fluorescence cell imaging also demonstrated sensor 1 can recognize iron ions in living cells.

中文翻译：

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基于恶二唑的“开关”荧光化学传感器，用于快速识别和检测水溶液和活细胞中的 Fe2+ 和 Fe3+

摘要 成功设计并合成了一种基于恶二唑的Fe3+/Fe2+化学传感器（传感器1）。传感器 1 在 THF:H2O (4:1, v/v) 溶剂中对 Fe3+ 和 Fe2+ 均显示出荧光猝灭响应，具有比所有其他竞争性金属离子高的选择性和灵敏度。乔布斯图、质谱、DFT 计算和荧光滴定表明，荧光猝灭是由传感器 1 和铁离子之间形成 1:1 的复合物引起的。传感器1在人体pH值下呈现高灵敏荧光响应，其荧光强度与铁离子浓度呈线性关系。传感器 1 还呈现出对铁离子的快速荧光响应和检测下限，Fe2+ 离子为 7.78 μM，Fe3+ 离子为 6.95 μM。传感器1可作为检测水样中铁离子的试纸。荧光细胞成像还表明传感器 1 可以识别活细胞中的铁离子。