A new ICT based Schiff-base chemosensor for colorimetric selective detection of copper and its copper complex for both colorimetric and fluorometric detection of Cysteine

Herein, a novel simple reversible Schiff base chemosensor (E)-N'-(4-(diethylamino)-2-hydroxybenzylidene)-2-(benzamido)benzohydrazide (L) has been designed, synthesised and characterised by X-ray single crystal analysis, H-1-NMR, IR spectroscopy, ESI-MS spectrometry and elemental analyses. The receptor L has been successfully applied for the detection of Cu2+ ions by colorimetry and L-Cu2+ complex for cysteine both colorimetry and fluorometry in aqueous-buffer medium. The detection limits reached up to 9.3 x 10(-7) M for Cu2+ and 5.86 x 10(-6) M for cysteine, which were far lower than those recommended by the WHO guidelines for drinking water. The other background cations Na+, K+, Ca2+, Mg2+, Fe3+, Co2+, Ni2+, Zn2+, Cd2+, Hg2+, Pb2+, Cr3+, Ag+, Al3+, Mn2+ and Fe2+ displayed no influence in the sensing process. The binding mode of the probe L with 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 INHIBIT and IMPLICATION logical devices.