Al-Sharifi Haitham K R, Meenakshy C B, Sandhya K S, Deepthi Ani
Department of Chemistry, University of Kerala, Kariavattom, Trivandrum, 695581, India.
College of Food Sciences, Al-Qasim Green University, Babylon, 51013, Iraq.
J Fluoresc. 2025 Apr 8. doi: 10.1007/s10895-025-04291-1.
In this study, we report the synthesis and photophysical evaluation of hydrazone 7 and azo 9 compounds of a thiazolo[3,2-a] indole derivative 5; latter synthesized as per our earlier report. Of the two compounds, the azo compound 9 showed exceptional selectivity and sensitivity as a dual sensor for detecting Fe and Cu ions via a turn-off fluorescence mechanism with limit of detection 0.09 µM and 0.14 µM respectively which are much lower than the US Environmental Protection Agency (EPA) guideline, 5.36 µM for Fe and WHO guideline, 31.5 µM for Cu in the drinking water. DFT calculations revealed that both Fe and Cu complexes with compound 9, and possess low HOMO-LUMO gap of 1.63 eV and 2.94 eV respectively. The binding stoichiometry for both metals was determined to be 1:1 by Job's plot. Stern-Volmer plot (plotted after applying correction to emission intensity), which showed a linear pattern, and fluorescence lifetime measurements indicated primarily a static quenching mechanism for both ions. The chemosensor 9 demonstrated exceptional reversibility and restorability in detecting both Fe and Cu, highlighting its potential for practical applications.
在本研究中，我们报告了噻唑并[3,2 - a]吲哚衍生物5的腙7和偶氮9化合物的合成及光物理评估；后者是按照我们之前的报告合成的。在这两种化合物中，偶氮化合物9作为一种双传感器，通过关闭荧光机制检测铁离子和铜离子时表现出卓越的选择性和灵敏度，其检测限分别为0.09 μM和0.14 μM，远低于美国环境保护局（EPA）的指导标准（饮用水中铁的标准为5.36 μM）以及世界卫生组织（WHO）的指导标准（饮用水中铜的标准为31.5 μM）。密度泛函理论（DFT）计算表明，铁和铜均与化合物9形成配合物，且其最高占据分子轨道（HOMO）与最低未占据分子轨道（LUMO）的能隙分别低至1.63 eV和2.94 eV。通过Job曲线确定两种金属的结合化学计量比均为1:1。斯特恩 - 沃尔默曲线（在对发射强度进行校正后绘制）呈线性，荧光寿命测量表明两种离子的猝灭机制主要为静态猝灭。化学传感器9在检测铁和铜时表现出卓越的可逆性和可恢复性，突出了其实际应用潜力。
