VOLTAMMETRIC STUDY OF THE SYSTEM CIS-TETRACHLORODI-µ-CARBOXYLATODIRHENIUM(III) – 1,3,5-TRIPHENYLVERDAZYL RADICAL IN ACETONITRILE

Abstract

Voltammetric study of the system consisted of cis-tetrachlorodi-μ-carboxylate dirhenium(III) and stable radical was conducted for detailization of the mechanism of interaction between the Re(III) coordination compounds with the metal-metal quadruple bond and the artificial radical. As a result of voltammetric studies, the electrochemical behavior of the cluster direnium(III) compound, triphenylverdazyl radical (TPV), and the mixture of the complex dirhenium(III) compound and the TPV – radical in acetonitrile were studied. It was found that the electrochemical behavior of the cluster dirhenium(III) compound cis-Re2(C10H15COO)2Cl4·2CH3CN and TPV – radical was similar in the cathode and anode regions. The selected dirhenium(III) complex and TPV interacted with the electron donor, and the TPV radical was more active than the dirhenium(III) complex under the investigated conditions. The results of calculations indicated the diffusion control of the rate of these electrochemical reactions. Positions of waves on the voltammetric curves, calculations of the reaction orders and the Semerano’s criterion showed that the interaction in the cis-Re2(C10H15COO)2Cl4·2CH3CN – TPV system was complex. Basing on the data obtained, the most probable mechanism is: the interaction of the electron donor and the cluster dirhenium(III) compound by transferring of only one electron to the quadruple bond of the Re26+ cluster fragment takes place, thereby reducing its order. Such a conclusion is confirmed the previously stated assumption about formation of a single-electron transfer of a stable for a short time particle of Re25+ in reactions with radicals.

Keywords

• реній, комплексні сполуки, почверний звязок, вільний радикал