Complexes of N-(2 Hydroxy-1-Naphthalidene) Antharanilic Acid with Some Lanthanides

The complexes of N-(2-hydroxy-1-naphthalidene)anthranilic acid abbreviated (H₂NA) with some trivalent rare earth elements (Pr, Nd, Sm, Gd, Dy, Er and Yb) were prepared. The complexes were characterized by chemical and thermal analysis, ir and conductimetric methods. Two types of ionic complexes; Ln(HNA)₂OH·2H₂O with Dy, Er and Yb, and Ln(HNA)₂OH with Pr, Nd, Sm and Gd were isolated. Coordination of the ligand with metal-ions occurs through the carboxy group and the nitrogen atom. The acid dissociation constants K₁ and K₂ of H₂NA and the overall stability constants β₁ and β₂ of some lanthanide complexes in 75% (v/v) dioxan-water solutions were determined by the potentiometric method.