Electrochemical characteristics of the copper(II)-copper(I) redox couple in dimethyl sulfoxide solutions
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A study of the electrochemical characteristics of the copper(II)/copper(I) redox couple has been made in chloride and bromide media in dimethyl sulfoxide (Me2SO) and their aqueous analogues. The formal potentials of the CuII/CuI couple in the Me2SO media are approximately 0.15 V less positive than in their aqueous counterparts probably due to a combination of solvation and complexation effects. Diffusion coefficients for both CuI and CuII are 5-10 times lower in Me2SO than in H2O as a result of the higher viscosity of Me2SO solutions. Heterogeneous electron-transfer rate constants for the CuII/CuI system on platinum are also an order of magnitude smaller than in aqueous solution. In general the electrochemical characteristics of the CuII/CuI system parallel those reported elsewhere for the FeIII/FeII couple. However, a detailed investigation of the CuII/CuI system by cyclic voltammetry indicates that the overall electrode process is complex, probably involving a quasi-reversible electron-transfer step coupled to a rate-determining loss of Cl - from CuII.
|Publication Type:||Journal Article|
|Murdoch Affiliation:||School of Mathematical and Physical Sciences|
|Publisher:||Commonwealth Scientific and Industrial Research Organization Publishing|
|Copyright:||© CSIRO 1990|
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