The electrochemical behavior of trans-[(ReO2)-O-(v)(en)(2)]I and trans[(ReO2)-O-(V) (en)(2)]ClO4 (en = ethylenediamine) complexes was studied by cyclic voltammetry on An electrodes. Experiments were performed in aqueous solutions at pH 7.0 and at room temperature. The complex voltammogram was characterized by Re-containing species, assigned to the [(ReO2)-O-(V)(en)(2)](+)/[(ReO2)-O-(IV)(en)(2)] couple, and I-containing species. To overcome I interference, the electrochemical response of Re complexes was segregated by performing a reductive desorption of adsorbed I from Au.