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Turn-on fluorescent capsule for selective fluoride detection and water purification.
- Source :
-
Chemical science [Chem Sci] 2022 Nov 30; Vol. 14 (2), pp. 291-297. Date of Electronic Publication: 2022 Nov 30 (Print Publication: 2023). - Publication Year :
- 2022
-
Abstract
- It has been a long-standing challenge to develop organic molecular capsules for selective anion binding in water. Here, selective recognition of aqueous fluoride was achieved through triple protonation of a hemicryptophane ( L ), which is composed of a fluorescent cyclotriveratrylene (CTV) cap and tris(2-aminoethyl)amine (tren) as the anion binding site. Fluoride encapsulation by [3H- L ] <superscript>3+</superscript> was evidenced by <superscript>1</superscript> H NMR, <superscript>19</superscript> F NMR, LC-MS, and X-ray crystallography. In addition, [3H- L ] <superscript>3+</superscript> exhibited a 'turn-on' fluorescence signal ( λ <subscript>em</subscript> = 324 nm) upon fluoride addition. An apparent association constant K <subscript>A</subscript> = (7.5 ± 0.4) × 10 <superscript>4</superscript> M <superscript>-1</superscript> and a detection limit of 570 nM fluoride were extracted from the fluorescence titration experiments in citrate buffer at pH 4.1. To the best of our knowledge, [3H- L ] <superscript>3+</superscript> is the first example of a metal-free molecular capsule that reports on fluoride binding in purely aqueous solutions with a fluorescence response. Finally, the protonated capsule was supported on silica gel, which enabled adsorptive removal of stoichiometric fluoride from water and highlights real-world applications of this organic host-guest chemistry.<br />Competing Interests: There are no conflicts to declare.<br /> (This journal is © The Royal Society of Chemistry.)
Details
- Language :
- English
- ISSN :
- 2041-6520
- Volume :
- 14
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Chemical science
- Publication Type :
- Academic Journal
- Accession number :
- 36687344
- Full Text :
- https://doi.org/10.1039/d2sc05352g