A Schiff base luminescent chemosensor for selective detection of Zn2+ in aqueous medium

Luminescent chemosensors based on Schiff bases have drawn tremendous research interest owing to their easy synthesis, enriched photophysical properties, and potential applications in biology and materials science. A dinitrophenyl-based Schiff base molecular probe ( L ) was synthesized and characterized to estimate its selective detection of Zn2+. The probe L exhibits weak emission in the DMSO-H2O solvent mixture due to excited-state intramolecular proton transfer (ESIPT). Interestingly, fluorescence is enhanced with the addition of Zn2+ to the DMSO-H2O solution of L, whereas the emission remains unchanged with the addition of other ions. This specifies that probe L acts as a selective chemosensor for Zn2+. The binding stoichiometry for the L : Zn2+ complex is 1:1, which was calculated using the Benesi-Hildebrand plot from fluorescence data. Furthermore, the binding modes are also supported by density functional theory (DFT) calculation. The binding constant and detection limits are 6.35 x 10(7) M-1 and 1.1 x 10(-8) M, respectively. The L-Zn2+ complex formation is reversible upon the addition of a strong chelating EDTA ligand. In addition, L is also used to detect Zn2+ in living Hela cells and selective sensing of Zn2+ in the solid phase. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

Luminescent chemosensors based on Schiff bases have been extensively studied due to their easy synthesis, enriched photophysical properties, and potential applications in biology and materials science. In this study, a dinitrophenyl-based Schiff base molecular probe (L) was synthesized and characterized for its selective detection of Zn2+. The probe exhibited weak emission in a solvent mixture, but fluorescence was enhanced in the presence of Zn2+, indicating its selective sensing ability.