A pyridine dicarboxylate based hydrazone Schiff base for reversible colorimetric recognition of Ni 2+ and PPi

A pyridine dicarboxylate Schiff-base DAS was synthesized for cascade colorimetric recognition of Ni and PPi. The selectivity and sensitivity of chemosensor DAS was investigated through colorimetric and UV-vis studies in MeOH-PBS (5 : 1, v/v, pH = 7.4). The chemosensor formed a 2 : 1 complex with Ni metal ions with a binding constant of = 3.07 × 10 M . Besides, a plausible sensing mechanism is confirmed by single crystal X-ray diffraction (SC-XRD), Job's plot and Benesi-Hildebrand plot (B-H plot) experiments. Furthermore, the DAS-Ni ensemble formed ' ' was used to selectively recognise PPi. The limit of detection (LOD) of DAS for Ni was found to be 0.14 μM and that of the DAS-Ni ensemble for PPi was found to be 0.33 μM. Also, the potential of the chemosensor has been applied for solid state detection of Ni as well as to mimic the 'INHIBIT' logic gate on the addition of Ni ions and PPi.