electrochemical studies of copper(II)complexes of Diamines, (Part 1).Electrochemical studies of copper(II) complexes of ethylenediamine at various pH values (original) (raw)

The cyclic voltammetric behaviour of copper (II) -Ethylenediamine systems with [Cu(II)]: [en] = 1:10, 1:100, 1:500 and 1:600 molar ratios, 1mM CuSO 4 .5H 2 O in Aqueous 0.2M NaClO 4 have been studied at pH values 7.10, 9.10 and 10.85 using cyclic voltammetry. The electrode process show quasi reversible one electron charge transfer preceded and followed by chemical reaction at glassy carbon electrode (G C E). At pH 10.85, the CV features for 1:10 and 1:100 molar ratios differ significantly as regards the oxidation process, while that of 1:100 and 1:500 are generally identical. Ipc 1 and Ipa 1 for 1:6x10 -3 M are significantly small indicating the formation of binuclear copper (II) complex or formation of Cu(en) 3 2+ in solution. At a given ligand ratio and at a given pH, Epc 1 , shifts anodically in the order 1:600 1:500≈1:100≈1:10.