New 2-{[(2-chloroquinolin-3-yl)Methylidene]amino}phenol (CQMAP) Schiff-base as colorimetric Chemosensor for Cr(III) detection: An Experimental and DFT Exploration

Abstract

In this investigation, a new Cr(III)-chemosensor, 2-{[(2-chloroquinolin-3-yl)methylidene]amino}phenol (CQMAP), had been successfully synthesized and characterized. The new chemosensor had been characterized using both NMR and FT-IR spectroscopy techniques. The CQMAP showcased remarkable sensitivity & selectivity, specifically against Cr(III) ions in aqueous media, even when challenged with various competing cations, such as Na(I), Mg(II), Al(III), K(I), Ca(II), Mn(II), Fe(II), Co(II), Ni(II), Zn(II), Sr(II), Ag(I), Cd(II), and Pb(II) respectively. The improved chemosensor underwent a distinctive colour transition to pale blue, offering a simple, clear and straightforward indication of Cr(III) presence. The CQMAP demonstrated a colorimetric assay for the optical/visual detection of Cr(III) ions with a detection limit of 14.65 ± 1.02 µM. The sensing action had been proposed by the formation of a complex with Cr(III) in a 1:3 stoichiometry (Cr(III) : CQMAP). Furthermore, the synthesized CQMAP underwent a meticulous characterization process using FT-IR, mass, Uv-vis. Spectroscopy, Thermal, conductivity, and magnetic behaviour measurements. The CrCQMAP complex had a binding constant of 1.84±1.21×104 M−1, forming a 1:3 stoichiometry with Cr(III) ions, providing insights into the strength of the interaction. These findings collectively underscore the robustness and versatility of CQMAP as an effective chemosensor for Cr(III) detection, showcasing its potential across diverse applications, including environmental monitoring and analytical chemistry.