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

Lasalocid forms 1:1 or 2:2 complexes with sodium ions. The process of compl exation was studied in different solvents at various temperatures by Na-23 NMR. The formation constants and be values were determined. The nature of t he complex between lasalocid and Na+ ions was also studied by FT-LR spectro scopy. 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, (C) 2000 Els evier Science B.V. All rights reserved.