Azo Schiff bases as colorimetric and fluorescent sensors for recognition of F⁻, Cd²⁺ and Hg²⁺ ions

Abstract

The optical and colorimetric sensing properties of H2L1–H2L3 for anions were investigated by the naked eye and UV-Vis and fluorescence spectroscopy. The spectral change of H2L1–H2L3 is due to the anion induced deprotonation and hence an increase in charge density and rigidity of the receptor molecule. The anion sensing abilities of the receptors toward halide anions were also monitored by electrochemical techniques.

RETRACTED: Synthesis and studies of selective chemosensor for naked-eye detection of anions and cations based on a new Schiff-base derivative

“…To assess the solvatochromic effect, the electronic absorption spectra of L (4⤬10 −5 mol.L − 1 ) in some organic solvents with different polarities were recorded at room temperature. As expected, the influence of solvents on the prepared dyes and/or changes in the hydrogen bonding strength in polar solvents [46,47]. The resulting values are summarized in Table 1.…”

“…Schiff bases containing salicyaldimine based ligands can be used in the development of cost-effective chemosensors because they show significant color changes of the solution and maxima of the absorption bond when they interact with anions and cations [45][46]. Recently, we reported aneasy and applicable method for the preparation [47] and use of low cost chemosensors based on Schiff bases for the selective detection of some toxic metal ions and anions [48,49]. Herein, we report for the first time novel colorimetric studies on cation and anion sensing by chromogenic azo-azomethine receptor (L) possessing a phenolic OH group and binds F − and H 2 PO 4 − (anion binding site).…”

Recognition of fluoride anions at low ppm level inside living cells and from fluorosis affected tooth and saliva samples

“…The interaction of F À with L have inuences on the electronic distribution of chromophore, which results in an appreciable color change with a new intraligand or internal charge transfer band. 9 Distinct isosbestic point at 407 nm (Fig. 5) also supports the complexation of L with F À .…”

Schiff Bases and Their Metallic Derivatives: Highly Versatile Molecules with Biological and Abiological Perspective

“…The first does it into a form of energy, and second transforms the chemical information into a useful signal, respectively. Recently, azo Schiff bases chemosensors have been studied to show high selectivity and sensitivity for the detection of Hg 2+ , Cd 2+ , and fluoride ions in the presence of competing cations/anions; these chemosensors can be utilized in DMSO by both selective coloration and change in the absorption spectra with a more prominent color change that is observable to the naked eye (Figure 4) [66,67].…”