Equilibrium Studies of Lanthanide(III) Complexes of (1-Phenyl-3-methyl-4-benzoyl-pyrazol-5-one) Anthranilic Acid and (1-Phenyl-3-methyl-4-benzoyl-pyrazol-5-one) Aminoantipyrine

Abstract

The stability constants of lanthanide(III) complexes of (1-phenyl-

3-methyl-4-benzoyl-pyrazol-5-one) anthranilic acid [Ln(PMBAA)₂NO₃]

and (1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one) aminoantipyrine

[Ln(PMBAAP)₃] complexes have been determined by potentiometric

method and the values obtained practically agree for the whole series of

lanthanide for both types of complexes. The IR spectral studies show that

in both complexes the ligands are similarly coordinated by carbonyl oxygen

atoms. In the [Ln(PMBAA)₂NO₃] complexes the nitrate ion also takes part

in coordination. The multiplet pattern of NMR spectra which partially

disappears show a more rigid pattern for PMBAA than for PMBAAP.