A reversible luminescent quinoline based chemosensor for recognition of Zn2+ ions in aqueous methanol medium and its logic gate behavior

A new Schiff-base receptor HL, based on 8-aminoquinoline and 2-imidazole carboxaldehyde has been investigated as a selective and sensitive reversible luminescent chemosensor for Zn2+ ions in aqueous methanol with detection limit in micromolar range. The fluorescence competition and ratiometric analysis were carried out in presence of various metal ions to confirm the selectivity of HL towards Zn2+ ions. The 'turn-on' fluorescence response for Zn2+ may be induced by the inhibition of C=N isomerization in HL-Zn2+. The binding property of HL with Zn2+ was examined by UV-vis and fluorescence studies. In presence of Zn2+, HL also exhibits reversible fluorescence change with EDTA and thus offers an interesting property of molecular 'INHIBIT' logic gate with Zn2+ and EDTA as chemical inputs. The potential utility of HL in sensing Zn2+ was also checked for real samples.