The Complexation of Lanthanides by Azo-B-Diketones Stability Constants

Abstract

The stability constants of the complexes between the trivalent lanthanide series of cations and series of azo-B-diketone ligands are reported. The measurements were conducted at 30°C and zero ionic strength (free KN03), in 100 % methanol. The relation between the overall stability constant (Log B;) and atomic number of lanthanide elements, shows a gadolinium-break. The relation between (Log Bz) and the basicity of the studied ligands ( 2 pKi + pKz) are, also discussed. The overall stability values obtained reflected a great affinity of the organic ligands for chelation with lanthanide ions.