A dipodal molecular probe for naked eye detection of trivalent cations (Al, Feand Cr) in aqueous medium and its applications in real sample analysis and molecular logic gates.

A simple and low cost multifunctional colorimetric receptor L has been designed, synthesized and characterized by H-NMR, IR spectroscopy, ESI-MS spectrometry and elemental analysis. The chemosensor L can selectively detect three biologically and environmentally important trivalent metal ions (Al, Feand Cr) both visually and spectrophotometrically in CHCN-HO (1 : 1, v/v) solution in the presence of other biologically relevant metal ions. The Job's plot analyses indicate the 2 : 2 binding stereochemistry for Al, Fe and Cr ions with L, which was further confirmed by H-NMR and ESI-MS studies. The binding constant values were found to be 2.9 × 10 M for Al, 1.079 × 10 M for Fe and 1.366 × 10 M for Cr respectively. The detections limits of the sensor for Al (2.8 × 10 M), Fe (1.9 × 10 M) and Cr (2.5 × 10 M) are far below than the limit set by the World Health Organization (WHO) for drinking water. Moreover, colorimetric test kits for rapid detection of Al, Fe, and Cr could be successively applied for all practical purposes, indicating its potential use in environmental samples. It has also been used in building molecular logic gates.