Equilibrium studies on mixed ligand complexes of lanthanides with some schiff bases and polycarboxylic acids

Abstract

Equilibrium studies have been done on the mixed ligand complexes of Ln(III) with ligands L and A where L = N-(salicylidene)-1H-2-benzimidazolylmethylamine (SBMA), N-(3-chlorosalicylidene)-1H-2-benzimidazolylmethylamine(SBMA), N-(3-methoxysalicylidene)1H-2-benzimidazolylmethylamine (MeO-SBMA); A = iminodiacetic acid (IMDA), hydroxyethyliminodiacetic acid (HIMDA), nitrilotriacetic acid (NTA) and Ln(III) = Pr(III), Nd(III), Dy(III), Gd(III), Y(III). Formation constants of binary 1:1:1 (ML), 1:2 (ML₂) and ternary 1:1:1 (MAL) complexes have been determined potentiometrically at 30°C in 60% (v/v) aqueous methanol at <em>I </em>= 0.1 <em>M </em>(NaClO₄). In these systems, the ligand L acts as a secondary ligand in the presence of A.