Abstract
Calix[4]arene-bis(crown-6) was converted into its di- and tetra-carboxy and hydroxy derivatives as water-soluble receptors. The complexation properties of these ionophores were studied for alkali cations in methanolic and aqueous media. Stability constants were calculated by UV–Vis spectroscopy. All ligands showed a more or less pronounced affinity for the larger cations. Cs+/Na+ selectivity is enhanced by the number and the nature of the substituents. Compound 7 represents the most selective ligand for the Cs+ cation in methanol and in basic aqueous media. For selective Cs+/Na+ separation, the efficiency of the ligands was evaluated by means of a nanofiltration system.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have