Formation constants of binary & ternary chelates of Ln(III) with maltol & kojic acid in presence of amino carboxylic acids

Abstract

The formation constants of binary and ternary systems involving 3-hydroxy-2-methyl-4-pyrone (HMP) (maltol) and 5-hydroxy-2-hydroxymethyl-4-pyrone (HOMP) (kojic acid), with lanthanide metal ions [La(III), Pr(II), Nd(III), Gd(III), Dy(III) and Y(III)] in the presence of iminodiacetic acid (IMDA), hydroxyethyliminodiacetic acid (HIMDA) and nitrilotriacetic acid (NTA) have been determined in aqueous medium at 30°C and μ = 0.1 <em>M </em>(NaClO₄). The order of stabilities of ternary systems is: HMP > HOMP and IMDA > HIMDA > NTA. These are explained in the light of the basi-cities of the Iigands and charge neutralisation.