Triazole derived azo-azomethine dye as a new colorimetric anion chemosensor

In the pursue of developing anion sensors, an efficient triazole derived azo-azomethine dye chemosensor (S) that differentially senses F- and AcO- ions has been reported. The ions recognition ability of S was investigated by colorimetric and UV-visible spectroscopic methods. Interestingly, this chemosensor molecule is virtually inactive in presence of other anions such as Cl-,(-) Br- and I- and HSO4-. We have further presented a ratiometric approach to differentiate F- and AcO- ions. The reversibility of F- ion binding with S was established by the addition of Ca (NO3)(2) to the fluoride bound S, which led to the regeneration of S. The quantum chemical calculation of energies of unbound and bound S has been employed using Density Functional Theory (DFT) to understand the interaction between chemosensor and anions. Evidence in support of fluoride-induced deprotonation of a O-H bond during the detection of F- ion has been demonstrated by employing H-1 NMR titration experiments. (C) 2019 Elsevier B.V. All rights reserved.