ABSTRACT Selective anion sensors can be used in the colourimetric detection of certain anions. In the present study, two new 1,2,4-triazole derivatives containing thiol group and azo moiety 3a (nitrile derivative) and 3b (methoxy derivative) were synthesised by condensation of 4-(4-amino-5-mercapto-4 H-1,2,4-triazol-3-yl)phenol (1) and aromatic aldehydes containing azo groups 2a and 2b under acidic conditions. The nitrile derivative 3a acted as a selective naked-eye sensor for acetate anions in a mixture of dimethyl sulphoxide and water (9:1 by volume). It interacted with the acetate anions in a 1:2 stoichiometry with strong positive cooperativity and an overall association constant (β12) exceeding 2 × 108 M−2. The detection limit of 3a towards the acetate anion was found to be 0.66 × 10−5 M. The DFT studies showed that both 3a and 3b were similar in their electronic properties, but the internal charge transfer for 3a was responsible for the positive response to acetate anions. GRAPHICAL ABSTRACT

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新型三唑席夫碱的合成、分光光度和 DFT 研究作为乙酸根阴离子的选择性肉眼传感器

摘要 选择性阴离子传感器可用于某些阴离子的比色检测。在本研究中，通过 4-(4-amino-5-mercapto-4 H) 缩合合成了两种含有硫醇基团和偶氮部分 3a（腈衍生物）和 3b（甲氧基衍生物）的新型 1,2,4-三唑衍生物。 -1,2,4-三唑-3-基)苯酚 (1) 和含有偶氮基团 2a 和 2b 的芳香醛在酸性条件下。腈衍生物 3a 在二甲基亚砜和水（体积比为 9:1）的混合物中充当乙酸根阴离子的选择性肉眼传感器。它以 1:2 的化学计量与乙酸根阴离子相互作用，具有很强的正协同性和超过 2 × 108 M−2 的总结合常数 (β12)。发现 3a 对乙酸根阴离子的检测限为 0.66 × 10-5 M。DFT 研究表明，3a 和 3b 的电子性质相似，但 3a 的内部电荷转移是对乙酸根阴离子的正响应的原因。图形概要