YTTRIUM AND LANTHANIDE CHELATES OF ARYLBIS (5-HYDROXY-3-METHYL-1-PHENYL-4-PYRAZOLYL) METHANE

Chelate stability constants of arylbis(5-hydroxy-3-methyl-1-phenyl-4-p yrazolyl) methane ligands (H(2)ArBPyM) with yttrium and some lanthanid e ions (M(3+)) were determined by potentiometric method at 30 degrees C and at an ionic strength of 0.1 with potassium nitrate in 75% (v/v) dioxane-water solvent. The computation of the titration data indicated that the values of the stability constants increased with the increas e of the atomic number. The stability constants of yttrium complexes a re between those for dysprosium and erbium ions. In these complexes H( 2)ArBPyM acts as a bidentate ligand coordination through the enolic ox ygens of the two pyrazolyl rings of the ligand.