Selective Detection of Zn2+ Ions by Ratiometric Receptor (E)-N′-(1-(2, 5-Dihydroxy phenyl) Ethylidene) Isonicotinohydrazide: A DFT Study

Abstract

The metal ion sensing characteristics of a novel Schiff-based ratiometric UV-visible chemosensor (E)-N’-(1-(2,5-dihydroxy phenyl)ethylidene) isonicotinohydrazide) (R1) has been explored. In EtOH:H2O (7:3, v/v), it has high sensitivity and selectivity for Zn2+ among a series of metal ions. With the addition of Zn2+ ions solution, R1 displayed discriminating spectral activity. The other metal ions did not affect R1 in any way. Furthermore, the addition of Zn2+ ions to R1 and LMCT action caused the shifting of the peak to a longer wavelength of 406 nm. The interaction of Zn2+ ions with R1 was further investigated using Density Functional Theory (DFT) investigations. Zn2+-R1 combination has a lower energy (2.2667 kcal.mol-1 to 0.9339 kcal.mol-1) than R1, indicating a strong connection with excellent stability. The Zn2+-R1 complex’s association constant (Ka) was discovered to be 6795M-1 and 6836M-1 using Benesi-Hildebrand and Scatchard plots respectively. The detection limit was determined to be 276 nM.

Keywords

• detection of zinc, ratiometric receptor, isonicotinohydrazide, dft study