Metal Complexes of Diamines, (Part III), Electrochemical Studies of Copper (II) Complexes of Tetraethylethylenediamine at Various pH Values

The cyclic voltammetric behaviour of copper (II) tetraethylethylenediamine systems with [Cu(II)]:[teen] =1:10, 1:100 molar ratios, 1x10M Cu(ClO4)2.6H2O in aqueous 0.2M NaClO4 supporting electrolyte have been studied at pH7.20, 9.10 and 10.85. The electrode process show quasi reversible one electron charge transfer preceded and followed by chemical reaction at glassy carbon electrode (GCE). For a given [Cu (II)]:[teen] molar ratio, Epc1 increases cathodically with pH. At a given pH, the value of Epc1 for 1:10 ≈1:100 indicating stability of complex species follow the same trend contrary to expectation. However, at a given metal: ligand ratio and at a given pH, Epc1 shifts anodically in the order en→tmen→teen, indicating that the ease of reduction also follows the same trend.