INVESTIGATIONS OF THE INTERACTION OF 4′,5′-BIS(SALICYLIDENEIMINO) BENZO-15-CROWN-5 WITH TRANSITION AND ALKALI METAL IONS AND THE URANYL CATION

Formation constants for complexes of Co(II), Cu(II), Ni(II) and U(VI)O 2 and 4,′5-bis(salicylideneimino)benzo-15-crown-5 (H 2 L) have been measured at 25 ± 0.1 °C and I = 1 M (KCl) by potentiometric techniques. Protonation constants of the ligand and overall formation constants have been calculated from potentiometric data using the program TITFIT. Both imino nitrogen and phenol groups provide donor atoms together with hydroxyl ions at higher pH values. The alkali ion binding capability of the crown ether groups of CuL and NiL measured by alkali extraction experiments gives the order K + > Na + > Li + .