Electrochemical and Spectroelectrochemical Study of Copper Complexes with 1,10-phenantrolines

The redox behaviour of a series of copper(II) complexes with different phenanthrolines (1:2 metal to ligand) in dimethylformamide solvent is reported. Cyclic voltammetry, controlled potential coulometry and spectroelectrochemistry in the visible region have been used. Accurate values for the formal potential of the copper(II)/copper(I) couples could be computed by spectroelectrochemistry, also in those cases in which the systems are poorly reversible. Two further reductions lead to neutral and anionic copper species, respectively. The nature of the substituents on the phenanthroline ligands has been found to affect strongly the redox potential of the former couples, while a less marked influence on the latter ones has been evidenced. On the other hand, differences in the ligands induce very different kinetic stability of the copper complexes formed in the more cathodic processes