Amide/urea-based simple fluorometric receptors for iodide and Hg2+ ions in aqueous medium: Aggregation induced emission and DFT studies

[Display omitted] •Amide and urea-based fluorometric receptors 1 and 2 were reported for I− and Hg2+ ions in aqueous medium.•Receptor 2 exhibited aggregation-induced emission at high pH.•Stern-Volmer plots and DFT studies explain fluorescence quenching with the presence of iodide ions.•Fluorescence...

Full description

Saved in:
Bibliographic Details
Published inSpectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 325; p. 125134
Main Authors Ghosh, Suprava, Malakar, Chandi C., Pahari, Pallab, Kumar Atta, Ananta
Format Journal Article
LanguageEnglish
Published Elsevier B.V 15.01.2025
Subjects
Online AccessGet full text

Cover

Loading…
More Information
Summary:[Display omitted] •Amide and urea-based fluorometric receptors 1 and 2 were reported for I− and Hg2+ ions in aqueous medium.•Receptor 2 exhibited aggregation-induced emission at high pH.•Stern-Volmer plots and DFT studies explain fluorescence quenching with the presence of iodide ions.•Fluorescence turn-on phenomena were observed after adding Hg2+ ions to the iodide complexes of the receptors.•Practical utilities for detecting I− and Hg2+ ions were highlighted. Herein, we report pyrene-tagged amide and urea-based sugar derivatives 1 and 2 in a simple synthetic pathway to recognize I− and Hg2+ ions. Both molecules showed absorbance and fluorescence selectivity towards iodide ions in THF/H2O (7/3, v/v) medium. The selectivity and sensitivity of 2 for iodide ions are superior to 1 due to more H-bond donors in 2. Interestingly, fluorometric receptor 2 exhibited aggregation-induced emission (AIE) at higher pH with a remarkable fluorometric color change. The AIE phenomenon might be explained by the self-association of 2 after forming imine functionality in the alkali medium. The Stern-Volmer plot showed the fluorescence quenching constant of each receptor with an iodide ion and indicated the quenching pathway. The LODs of 1 and 2 for iodide ions were evaluated as 0.84 and 0.17 µM, respectively. The 1:1 binding stoichiometry of 1 or 2 with iodide was found from the Job plot and verified by measuring the complex mass. Further, the complexes of each receptor with I− ions can detect Hg2+ ions selectively by fluorescence turn-on method with low sensitivities (LODs: 0.008 µM for 1 and 0.01 µM for 2). DFT results were used to understand the binding mode of receptors 1 and 2 with iodide ions and the quenching process in the aqueous THF medium. The real application of the receptors was established for the recovery of iodide and Hg2+ ions from natural water samples.
ISSN:1386-1425
DOI:10.1016/j.saa.2024.125134