FRET-based ‘ratiometric’ molecular switch for multiple ions with efficacy towards real-time sampling and logic gate applications

Dey, N and Kumari, N and Bhattacharya, S (2021) FRET-based ‘ratiometric’ molecular switch for multiple ions with efficacy towards real-time sampling and logic gate applications. In: Tetrahedron, 85 .

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Abstract

Fluorescent nanoaggregates comprised of rhodamine based amphiphilic probe has been designed, which can simultaneously detect Al3+, Cr3+ and F¯ ions in the aqueous medium (pH 7.4). Mechanistic investigation indicates that both the carbonyl oxygen of the spirolactam ring and the nitrogen center of indole participate in the coordination of metal ions. Consequently, metal ion-binding induces the opening of the spirolactam ring and allows the Förster energy transfer from indole to xanthene moiety. As a result, the colorless probe solution turns pink in presence of metal ions, with ratiometric fluorescence change from blue to yellow. Further, the addition of fluoride leads to dissociation of preformed Al3+-complex, resulting in the fading of pink color and reverting the fluorescence signal to the original. This not only serves as a tool to discriminate between Al3+ and Cr3+ ion but also acts as a strategy for detecting fluoride in the aqueous medium. Thus, using a single FRET probe, ‘ratiometric’, naked-eye sensing of multiple ions was achieved. Also, considering the differential response of probe molecule towards Cr(III) and Cr(VI), a colorimetric assay for biogenic thiols was developed. Simultaneously, a combinatorial molecular logic gate was designed based on the multiple ion sensing ability of the probe molecule. Further, the system showed real-time detection of Al3+ and Cr3+ in natural water samples, estimation of Al3+ in antacid tablets and fluoride in mouthwash, etc. Lastly, low-cost, reusable paper strips were developed, which offers an alternative strategy for on-site detection of metal ions without engaging any sophisticated instruments or trained personnel.

Item Type:	Journal Article
Publication:	Tetrahedron
Publisher:	Elsevier Ltd
Additional Information:	The copyright for this article belongs to Elsevier Ltd.
Keywords:	aluminum; carbonyl derivative; chromium; fluoride; indole; ion; nitrogen; oxygen; thiol; water; xanthene, aqueous solution; Article; calculation; colorimetry; controlled study; dissociation; fluorescence resonance energy transfer; measurement; metal binding; molecular logic gate; molecule; multiple ion sensing; pH; quantum yield; real time sampling; sampling; water sampling
Department/Centre:	Division of Chemical Sciences > Organic Chemistry
Date Deposited:	13 Apr 2023 09:35
Last Modified:	13 Apr 2023 09:35
URI:	https://eprints.iisc.ac.in/id/eprint/80610

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