Quinoxaline based Schiff bases: An effective calorimetric chemosensor for cyanide ion detection, application in logic gate and DFT studies

Abstract

Cyanide ion is very toxic for both environment and human being, so it is necessary to design a chemosensor for cyanide ion detection. For this purpose, Two novel chemosensors based on 3-hydrazinylquinoxalin-2(1H)-one and aromatic aldehydes were synthesized named as (E)-3-(2-(5-fluoro-2-oxo-1H-indol-3(2H,3aH,7aH)-ylidene)hydrazinyl)quinoxalin-2(1H)-one (HG-1) and (Z)-3-(2-(4-morpholinobenzylidene)hydrazinyl)quinoxalin-2(1H)-one (HG-2) for selective detection of cyanide ion. The structural characterization was done by analytical techniques such as UV/Visible, FTIR, 1HNMR, 13CNMR, EI-MS and UPLC. Further confirmation of chemosensor sensing was done by DFT and TDDFT calculations with B3LYP/6-31G (d, p) method by performing QTAIM, FMO, UV/Vis and global reactivity parameters (GRPs) elucidation. The binding constant was calculated as 4.14 × 106 M−1 and detection limit was calculated as 21 × 10−6 M. In the presence of CN͞ ion, chemosensor HG-1 generated a noticeable color change from light yellow to orange. To build a combinatorial logic circuit gate, the reverse reaction of chemosensor with methanol is useful. Overall results shows that chemosensor HG-1 has greater selectivity for CN͞ ion than HG-2. Test strips were made for CN͞ ion detection.