Solvent tuned discriminant sensing of Al3+, Mg2+ and HF2- by vanilinyl-picolinyl hydrazide Schiff base
Vanilinyl-piconilyl hydrazide dyad Schiff base (HVPh) is structurally characterized by single crystal X-Ray diffraction data. The molecule exhibits intense green fluorescence in solid state and serves as solvent tuned dual detector to Mg2+ and Al3+ and secondary sensor to HF2-. Mg2+ impart yellow emission at 522 nm (LOD, 45 nM) in DMSO while intense blue emission for Al3+ in pure water at 460 nm (LOD, 7.4 nM) is observed. The probe forms 1:1 complex with Al3+, and 1:2 complex with Mg2+ and the composition of complexes are established by NMR, Mass and FTIR spectral data. The study of anion sensitivity of the complexes shows that the HF2- efficiently quenches the emission of the complexes and the LOD are far below the WHO recommended data (Mg2+, 200 mM; Al3+, 7.41 mM; F-, 3.68 M). A recovery study has been performed to check the practical applicability of the probe using drinking water supplied by Kolkata Municipality Corporation in the Jadavpur University campus. Molecular INHIBIT logic gate has also been constructed by the sensor. DFT and TDDFT computation technique is used to explain the experimental findings.