23Na NMR and FT-IR studies of sodium complexes with the ionophore lasalocid in solution

Abstract

Lasalocid forms 1:1 or 2:2 complexes with sodium ions. The process of complexation was studied in different solvents at various temperatures by 23Na NMR. The formation constants and ΔG values were determined. The nature of the complex between lasalocid and Na+ ions was also studied by FT-IR spectroscopy. In chloroform, a 2:2 complex of lasalocid and Na+ ions is formed. A continuous absorption is observed in the far FT-IR spectrum of this complex. It indicates the large Na+ polarizability due to fast fluctuations of the Na+ ions in multiminima potentials, in the dimeric structure.