Concentration dependent colour switching of tryptophan-derived 3,5-dinitrobenzamide ligands in the presence of fluoride anions

摘要

Interactions of fluoride anions with 3,5-dinitrobenzamide ligands containing pendant leucine (1) and tryptophan (2) residues respectively, produced dramatic concentration-dependent switching of colour in solutions. ~1H NMR spectroscopy revealed that the coordination of fluoride to 2 invoked participation of the tryptophan residue which was indicative of anion-π interactions. In addition, we have developed a chromogenic fluoride sensor from 2, immobilised in polystyrene film, which was applicable in aqueous solutions.