Turn‐on fluorescent probe for Zn<sup>2+</sup> ions based on thiazolidine derivative
Hayriye Genç Bilgiçli, Ahmet T. Bilgiçli, Armağan Günsel, Burak Tüzün, Derya Ergön, M. Nilüfer Yaraşır, Mustafa Zengin
Abstract
In this study, simple on–off fluorescent/UV–visible (UV–Vis) probes were easily prepared using 2‐(2‐hydroxyphenyl)thiazolidine‐4‐carboxylic acid ( Sen‐1 ) and/or 2‐(2‐hydroxy‐5‐nitrophenyl)thiazolidine‐4‐carboxylic acid ( Sen‐2 ) for fast detection of Zn 2+ ions. Their sensing properties towards common metal ions were investigated using UV–Vis and fluorescence spectroscopies. Sen‐1 and Sen‐2 displayed a significant change with the addition of Zn 2+ ions in the UV–Vis spectra. The addition of Zn 2+ ions induced a 104 nm bathochromic shift for Sen‐1 . The binding ratio towards Zn 2+ metal ions was determined to be 1:1 by using Job plot analysis and fluorescence spectroscopy. The association constant and free energy (Δ G ) of Sen‐1 and Sen‐2 towards Zn 2+ ions were calculated by the Benesi–Hildebrand equation. The limit of detection of Sen‐1 towards Zn 2+ ions is 3.73 × 10 −8 M, which is about 1/100 of the value recommended by the World Health Organization for drinking water. Sen‐1 was successfully applied to detect Zn 2+ ions in water samples and the fluorescence test strip was prepared for visual detection of Zn 2+ ions. Finally, the quantum chemical parameters of Sen‐1 and Sen‐2 , such as highest occupied molecular orbital, lowest unoccupied molecular orbital, and chemical hardness, were investigated by the Becke, three‐parameter, Lee–Yang–Parr, Hartree–Fock, and M062x methods.