Triphenylamine based new Schiff base ligand: Solvent dependent selective fluorescence sensing of Mg 2+ and Fe 3+ ions

A new Schiff base ligand based on triphenylamine (1) was synthesized and demonstrated solvent dependent selective fluorescence sensing of Mg 2 + and Fe 3 + ions up to ppm level (10 − 6 M). Highly selective turn-on fluorescence for Mg 2 + was observed in DMSO as well as DMF (λ max = 506 nm, Φ = 0.007 (1), 0.17 (1 + Mg 2 + )). Interestingly, in THF, 1 showed strong turn-on fluorescence for Fe 3 + (blue, λ max = 460 nm, Φ = 0.064) as well as for Mg 2 + (greenish yellow). Interference studies confirm that Ca 2 + that strongly competes with Mg 2 + sensing had negligible interference. The practical application of 1 for selective fluorescence sensing of Mg 2 + from different water samples has also been demonstrated.