M S Thippeswamy, Naik Lohit, Maridevarmath C V, Malimath G H
Department of Physics, Government First Grade College, Harihara, 577601, Karnataka, India.
Department of Physics and Electronics, CHRIST(Deemed to Be University), Bangalore, 560029, Karnataka, India.
J Fluoresc. 2022 Jul;32(4):1543-1556. doi: 10.1007/s10895-022-02946-x. Epub 2022 May 11.
In the present work, the fluorescence quenching of novel thiophene substituted1,3,4-oxadiazole derivative 2-(4-(4-vinylphenyl) phenyl)-5-(5-(4-vinylphenyl)thiophen-2-yl)-1,3,4-oxadiazole (TSO) by five different environmental pollutant aromatic amine derivatives like 2,4-dimethylaniline, 3-chloroaniline, 4-chloroaniline, o-anisidine, and m-toluidine has been studied at room temperature through steady-state and time-resolved methods. It is observed that, the quenching efficiency is highest in the case of o-anisidine and least in the case of 3-chloroaniline. The fluorescence quenching mechanism between TSO and aromatic amines is analysed through different quenching models. The results suggest that, the fluorescence quenching is due to diffusion assisted dynamic or collisional quenching according to the sphere of action static quenching model and according to the finite sink approximation model, the bimolecular quenching reactions are due to the collective effect of dynamic and static quenching. Further, cyclic voltammetry and DFT studies suggest that the fluorescence quenching is due to electron transfer. Binding equilibria analysis confirms the 1:1 stoichiometric ratio between fluorophore and the quencher.
在本工作中，通过稳态和时间分辨方法，研究了新型噻吩取代的1,3,4 - 恶二唑衍生物2-(4-(4 - 乙烯基苯基)苯基)-5-(5-(4 - 乙烯基苯基)噻吩 - 2 - 基)-1,3,4 - 恶二唑(TSO)被2,4 - 二甲基苯胺、3 - 氯苯胺、4 - 氯苯胺、邻甲氧基苯胺和间甲苯胺这五种不同环境污染物芳香胺衍生物在室温下的荧光猝灭情况。观察到，邻甲氧基苯胺的猝灭效率最高，3 - 氯苯胺的猝灭效率最低。通过不同的猝灭模型分析了TSO与芳香胺之间的荧光猝灭机制。结果表明，根据作用球静态猝灭模型，荧光猝灭是由于扩散辅助的动态或碰撞猝灭，根据有限阱近似模型，双分子猝灭反应是动态和静态猝灭的共同作用。此外，循环伏安法和密度泛函理论研究表明荧光猝灭是由于电子转移。结合平衡分析证实了荧光团与猝灭剂之间的化学计量比为1:1。
