In our works it was shown that halogenocarboxylates of dirhenium(III) revealed different kinds of a biological activity together with low toxicity. These properties was explained by their antioxidant abilities. The quadruple bond rhenium - rhenium is present in structures of all investigated substances, contains quite active δ-component and may be responsible for abilities mentioned above. In this connection it was interesting to investigate interaction of cluster Re2 6+ compounds with stable free radicals, such as 1,3,5-triphenylverdazyle radical (Vd). As a result of reaction with electron transition the Vd-radical (Vd) turned to Vd-cation. Such transition can be easily determined with the help of electronic absorption spectra (EAS). With the help of EAS it is possible also to establish existance of a quadruple bond rhenium - rhenium in halogenocarboxylates of dirhenium(III) in visible area according to δ→δ* - electronic transition. Thus, EAS is a reliable method for investigation the convertions in the system Vd – derivatives of Re2 6+. Disappearance of a maximum of absorption, which really characterizes δ→δ* - electronic transition confirmed the break of δ-component of the bond between rhenium atoms. With the help of EAS we investigated antiradical activity for cis-Re2(RCOO)2Cl4, transRe2(RCOO)2Cl4, Re2(RCOO)3Cl3, Re2(RCOO)4Cl2 (where R-alkyl group). The analysis of obtained results has shown, that the gradual replacement of halogenide ligands on carboxylic in clusters of dirhenium(III) led to hindrance of reaction with Vd-radical, that took place due to different influence of these ligands on parameters of rhenium - rhenium bond. Moreover, with increasing of inductive effect of alkyl groups the speed of the reaction decreased. Such fact can be explained by more strong pressing of electronic density to bond, for which effect of conjugation with COO- group and formation of five-term cycle was observed, and strengthening of bond, was as a result of which handicapped its break with the help of a radical. The conducted researches have shown perspectivity of use of derivatives of Re2 6+ as low-toxic materials with antiradical activity in medical experiments.