Structural Features of a Family of Coumarin-Enamine Fluorescent Chemodosimeters for Ion Pairs
Document Type
Article
Publication Date
9-1-2021
Department
Chemistry and Biochemistry
School
Mathematics and Natural Sciences
Abstract
A family of coumarin–enamine chemodosimeters is evaluated for their potential use as fluorescent molecular probes for multiple analytes [cadmium(II), cobalt(II), copper(II), iron(II), nickel(II), lead(II), and zinc(II)], as their chloride and acetate salts. These fluorophores displayed excellent optical spectroscopic modulation when exposed to ion pairs with different Lewis acidic and basic properties in dimethyl sulfoxide (DMSO). The chemodosimeters were designed to undergo excited-state intramolecular proton transfer (ESIPT), which leads to significant Stokes shifts (ca. 225 nm) and lower-energy fluorescence emission (ca. 575 nm). A more basic anion, e.g., acetate, inhibited the ESIPT mechanism by deprotonation of the enol, producing a binding pocket (N^O– chelate) that can coordinate to an appropriate metal ion. Coordination of the metal ions enhances the fluorescent intensity via the chelation-enhanced fluorescence emission mechanism. Subjecting the spectroscopic data to linear discriminant analysis provided insights into the source of these systems’ markedly different behavior toward ion pairs, despite the subtle structural differences in the organic framework. These compounds are examples of versatile, low-molecular-weight, dual-channel fluorescent sensors for ion-pair recognition. This study paves the way for using these probes as practical components of a sensing array for different metal ions and their respective anions.
Publication Title
Inorganic Chemistry
Volume
60
Issue
18
First Page
14238
Last Page
14252
Recommended Citation
Davis, A.,
Ihde, M.,
Busenlehner, A.,
Davis, D.,
Mia, R.,
Panella, J.,
Fronczek, F.,
Bonizzoni, M.,
Wallace, K. J.
(2021). Structural Features of a Family of Coumarin-Enamine Fluorescent Chemodosimeters for Ion Pairs. Inorganic Chemistry, 60(18), 14238-14252.
Available at: https://aquila.usm.edu/fac_pubs/19597