Axial ligation constants of copper(II) macrocyclic tetra-amine complexes

Abstract

The effect of solvent on the axial ligation constants of red (C-meso- and red (C-rac-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetra-azacyclotetradecane)copper(II) complexes with Cl^–, Br^–, I^–, and N₃^– in dimethylformamide, dimethyl sulphoxide, methanol, and water has been studied by spectrophotometric techniques. The sequence for the axial ligation constants varies in the order K_H2OK_dmso < K_dmf < K_MeOH. A linear relationship between the relative free energies of solvation for the anions in organic and aqueous solvents and the relative free energies of ligand addition to copper(II) macrocyclic complexes in these solvents was obtained.