Interactions between Metal Cations and the Ionophore Lasalocid Part 5.- A Potentiometric, Polarographic and Electron Spin Resonance Study of Copper(II)-Lasalocid Equilibria in Methanol

Article abstract of DOI:10.1039/f19888403175

The complexation of Cu²⁺ by lasalocid and the model compound salicylic acid, AH, has been studied in methanol.The stability constants of species ACu⁺ and A₂Cu were obtained from potentiometric measurements using a pH glass electrode and a copper-selective electrode, and by polarographic determinations.The stability of these copper(II) complexes was shown to be higher than that of the analogous complexes of the other transition-metal cations of the first row and very similar for lasalocid and salicylic acid.The e.s.r. spectra suggest that the structures of the species formed with the two ligands differ; the oxygen of the backbone probably participates in complexation with lasalocid.In addition, other complexes possibly involving the methoxide ion, formed in more basic media, were characterised.