Studies of some ternary complexes of copper(II) involving tridentate and monodentate ligands

Abstract

The stability constants of the ternary complexes, CuAL, where A refers to pyridine 2,6-dicarboxylic acid (PDA) and iminodiacetic acid (IMDA), and L refers to imidazole, benzimidazole, pyridine and <i>ϒ</i>-picoline have been determined potentiometrically using SCOGS computer program. The order of stabilities of the mixed ligand complexes is [Cu-PDA-L] &lt; [Cu-IMDA L]. The value of ∆log <i>K </i> is positive or less negative when A is IMDA. Most of the mixed ligand complexes have been isolated in solid state and characterised. Electronic spectra indicate that there is no significant interaction between two ligands through the metal <i>d_π </i> orbitals in the mixed ligand complexes.