A novel Schiff base: Synthesis, structural characterisation and comparative sensor studies for metal ion detections

•A novel Schiff base compound (L) was synthesised and characterised.•Molecular structure of the compound was determined by single crystal X-ray diffraction study.•Visual colour change of the ligand was investigated in MeOH solvent in presence of various metal ions.•Sensor ability of the Schiff base compound to sense metal ions were investigated by colorimetric and fluorometric methods.

A novel Schiff base ligand was synthesized by the condensation reaction of 2,6-diformylpyridine and 4-aminoantipyrine in MeOH and characterised by its melting point, elemental analysis, FT-IR, 1H, 13C NMR and mass spectroscopic studies. Molecular structure of the ligand was determined by single crystal X-ray diffraction technique. The electrochemical properties of the Schiff base ligand were studied in different solvents at various scan rates. Sensor ability of the Schiff base ligand was investigated by colorimetric and fluorometric methods. Visual colour change of the ligand was investigated in MeOH solvent in presence of various metal ions Na+, Mg2+, Al3+, K+, Cr3+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+ and Pb2+. Upon addition of Al3+ ion into a MeOH solution of the ligand, an orange colour developed which is detectable by naked eye. Fluorescence emission studies showed that the ligand showed single emission band at 630–665 nm upon excitation at 560 nm. Addition of metal ions Na+, Mg2+, K+, Cr3+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+ and Pb2+ (1:1 M ratio) cause fluorescence quenching, however addition of Al+3 resulted in an increase in fluorescence intensity. No significant variation was observed in the fluorescence intensity caused by Al3+ in presence of other metal ions. Therefore, the Schiff base ligand can be used for selective detection of Al3+ ions in the presence of the other metal ions studied.

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