Compatibility of nitrilotriacetic acid and 3-acetyl-4-hydroxy-6-methyl-2-pyrone in the coordination sphere of lanthanon ions

A study of the competetion of 3-acetyl-4-hydroxy-6-methyl-2-pyrone (dehydracetic acid, DHA) and nitrilotriacetic acid (NTA) in the coordination sphere of lanthanon ions has been carried out by calculating reproportionation constant which relates the stability of the mixed ligand complex to those of the parent complexes formed by the same ligands. It has been found that NTA and DHA are incompatible ligands and mixed ligand complexes formed are less stable than either of the parent complexes. The fact is also supported by the observed change in free energy occuring during mixed ligand complex formation. All these studies have been carried out at 30.0 +- 0.50 and μ-0.01 (NaClO4) in 50 percent v/v aqueous dioxane medium. (author)