Isatin as a simple, highly selective and sensitive colorimetric sensor for fluoride anion

Heterocyclic communications

article

Azeem Haider¹  Mukhtiar Ahmed¹  Muhammad Faisal¹  Muhammad Moazzam Naseer¹ 

[1] Department of Chemistry, Quaid-i-Azam University-45320

关键词: Isatin;    chromogenic sensor;    ion detection;    fluoride;    UV-Vis titrations;    DFT calculations;   

DOI  :  10.1515/hc-2020-0003

学科分类：内科医学

来源: De Gruyter

【 摘 要 】

Herein, we report the fluoride anion sensing properties of a commercially available and inexpensive organic compound, isatin, which is found to be a highly selective and sensitive sensor. In naked-eye experiments, by addition of fluoride anions, isatin shows a dramatic color change from pale yellow to violet at room temperature, while the addition of other anions, i.e . Cl− ,$\mathrm{Cl}^-,$Br− ,I− ,ClO4− ,H2PO4− andPF6− ,$\mathrm{Br}^-,\mathrm I^-,\mathrm{ClO}_4^-,{\mathrm H}_2\mathrm{PO}_4^-\,\mathrm{and}\,\mathrm{PF}_6^-,$did not induce any colour change. Additionally, recognition and titration studies have also been done through UV/Vis spectroscopy. Isatin displayed a new absorption band at 533 nm after the addition of fluoride anions, which is presumably due to acid-base interaction between isatin and fluoride anions, while other anions did not trigger noticeable spectral changes. The detection limit was observed to be 0.367 ppm. DFT calculations were also performed to further explain the behavior of receptor 1 towards the Fˉ anion. Owing to high sensitivity and selectivity, isatin can be useful in the detection of biologically or environmentally important fluoride anions at very low concentration.

【 授权许可】

CC BY|CC BY-NC-ND