Novel bis(rhodamine)-based fluorescence sensor for highly selective detection of Al(III): DFT mechanistic studies and analysis in real samples
Issued Date
2026-01-05
Resource Type
ISSN
00222860
Scopus ID
2-s2.0-105013672260
Journal Title
Journal of Molecular Structure
Volume
1349
Rights Holder(s)
SCOPUS
Bibliographic Citation
Journal of Molecular Structure Vol.1349 (2026)
Suggested Citation
Promkatkaew M., Sakulsaknimitr W., Rakdee K., Thanabunrit P., Chomngam S., Kongsaeree P., Srisuratsiri P. Novel bis(rhodamine)-based fluorescence sensor for highly selective detection of Al(III): DFT mechanistic studies and analysis in real samples. Journal of Molecular Structure Vol.1349 (2026). doi:10.1016/j.molstruc.2025.143681 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/114737
Title
Novel bis(rhodamine)-based fluorescence sensor for highly selective detection of Al(III): DFT mechanistic studies and analysis in real samples
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Abstract
A novel bis(rhodamine)-based sensor, BRTDA, was synthesized and its molecular structure and interaction with Al<sup>3+</sup> ions were investigated. The BRTDA probe, featuring two rhodamine moieties linked by a 2,5-thiophene dicarboxylic acid, was designed to exhibit enhanced fluorescence upon Al<sup>3+</sup> binding. In a CH<inf>3</inf>CN–H<inf>2</inf>O (v/v) 2:1 solution, the probe is colorless, but the addition of Al<sup>3+</sup> induces a color change to pink and a substantial increase in fluorescence. Density functional theory calculations revealed that this fluorescence enhancement is associated with a distinct change in the molecular structure of BRTDA upon Al<sup>3+</sup> coordination. Specifically, the energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) decreased markedly from 3.246 eV for free BRTDA to 2.127 eV for the BRTDA-Al³⁺ complex, which corresponds with the observed fluorescence enhancement. The sensor displays a detection limit for Al<sup>3+</sup> of 76.3 nM, a linear range of 0–66.7 µM, and a 1:1 binding stoichiometry with Al<sup>3+</sup>. The BRTDA sensor was applied successfully to determine Al<sup>3+</sup> levels in tap water and mineral water.