A benzohydrazide based two-in-one Ni2+/Cu2+ fluorescent colorimetric chemosensor and its applications in real sample analysis and molecular logic gate

Herein, a simple reversible Schiff base chemosensor N-(2-hydroxybenzylidene)-2-(benzamido)benzohydrazide (L) has been designed, synthesised and characterised by( 1)H-NMR, IR spectroscopy, ESI-MS spectrometry, elemental analyses and X-ray single crystal studies. The receptor L has been successfully applied for the detection of Ni(2+ )and Cu2+ ions, both colorimetrically and fluorometrically in aqueous medium. The detection limit reached up to 2.22 x 10(-6)M and 2.04 x 10(-7) M for chromogenic measurements and 1.61 x 10(-6) M and 2.26 x 10(-6)M from fluorogenic measurements for Ni2+ and Cu2+ ions respectively, which were far lower than those recommended by the WHO guidelines for drinking water. The other background cations Fe3+, Zn (2+), Cd (2+), Hg (2+), Pb (2+), Cr3+, Ag+, Al (3)+ , Fe2+ and Mn(2+ )displayed no influence in the sensing process. The binding mode of the probe L with Ni(2+ )and Cu2+ ion is determined to be a 1:1 complexation stoichiometry using Job's plot analysis and further confirmed by ESI-MS spectra and DFT calculations. The synthesized chemosensor (L) finds application in real sample analysis and formation of binary logical devices.