Affiliation:
1. Department of Chemistry Bio-organic Laboratory University of Delhi Delhi 110 007 India
2. Computational Chemistry Group Department of Chemistry University of Delhi Delhi 110007 India
Abstract
AbstractThree novel isatin‐triazole tethered tetrahydropyridine‐based colorimetric chemosensors were synthesized for selective recognition of Fe3+ ions. Their selectivity and sensitivity were investigated through colorimetric and UV‐Visible studies in a mixed‐aqueous medium (MeOH/H2O (7 : 3, v/v)). The binding stoichiometry of Chemosensor 3‐methyl 1‐phenyl (5S,6R)‐5‐bromo‐6‐(4‐((2,3‐dioxoindolin‐1‐yl)methyl)‐1H‐1,2,3‐triazol‐1‐yl)‐5,6‐dihydropyridine‐1,3(2H)‐dicarboxylate (6 a) was found to be 1 : 1 with the highest binding constant Ka, 8.6×103 M−1. The detection limit of 6 a for Fe3+ ions (0.47 μM) was much lower than the maximum permissible limit of Fe3+ ion according to Environmental Protection Agency (EPA). Moreover, the 6 a‐Fe3+ complex was found to be recyclable upon the addition of EDTA. Furthermore, the reversible colorimetric changes of 6 a on adding Fe3+ ions and EDTA were found to mimic the ‘INHIBIT’ molecular logic gate. The chemosensor 6 a recognizes Fe3+ ions by binding through oxygen atoms of isatin as confirmed by Density Functional Theory (DFT) studies.