Abstract
The present work discusses copper(II) complexes of 13-membered macrocyclic ligands carrying electronic substituents on the ligand periphery. The complexes have been thoroughly characterized including crystallographic investigations of two representative compounds. The crystal structures confirm that the metal center is coordinated by two deprotonated N-amide and two neutral N-amine atoms in an N-4 basal plane within the macrocyclic cavity. The electrochemical studies suggest that the different electronic substituents present on the ligand periphery (-H, -Cl, -CH3, and -OCH3) significantly alter the Cu-III-Cu-II potential values. Based on the electrochemical findings, the transient Cu(III) species generated coulometrically are characterized by their absorption spectra.