Abstract In this study, we describe the anion recognition ability of isatin-3-thiosemicarbazone 2, which contains two different anion recognition units i.e. isatin NH and the thiourea moiety. Both have the ability to act as proton donors. Most importantly, a significant colour change of 2 was observed (from light yellow to reddish orange) in organic medium only after the addition of the F– anion. No such colour change could be observed for any other anions including Cl–, Br–, I–, H2PO4−, ${{\text{H}}_{2}}\text{P}{{\text{O}}_{4}}^{-},$ NO2−, $\text{N}{{\text{O}}_{\text{2}}}^{-},$ PF4− $\text{P}{{\text{F}}_{4}}^{-}$etc. The UV-Vis spectroscopic studies also indicate the potential of this compound for selective detection of fluoride anions. 1H-NMR titrations clearly indicate the formation of the 2.F– anionic complex. The Density-functional theory (DFT) calculations are also performed to get further insights on the formation of 2.F– complex.

中文翻译：

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Isatin-3-thiosemicarbazone 作为用于选择性检测氟阴离子的显色传感器

摘要 在这项研究中，我们描述了靛红-3-氨基硫脲2 的阴离子识别能力，它包含两个不同的阴离子识别单元，即靛红NH 和硫脲部分。两者都有作为质子供体的能力。最重要的是，仅在添加 F- 阴离子后，才在有机介质中观察到 2 的显着颜色变化（从浅黄色到红橙色）。对于任何其他阴离子，包括 Cl–、Br–、I–、H2PO4−、${{\text{H}}_{2}}\text{P}{{\text{O} }_{4}}^{-},$ NO2−, $\text{N}{{\text{O}}_{\text{2}}}^{-},$ PF4− $\text{ P}{{\text{F}}_{4}}^{-}$等。紫外-可见光谱研究还表明该化合物具有选择性检测氟阴离子的潜力。1H-NMR 滴定清楚地表明 2.F-阴离子复合物的形成。