Electrochemistry of icosahedral cobalt bis(dicarbollide) ions and their carbon and boron substituted derivatives in aqueous phosphate buffers

Herein we present investigations of electrochemical behavior over a series of selected bisicosahedral cobalt bis(heteroborane)(1-) derivatives in aqueous phosphate buffers. This pilot study is focused on distinct effects connected with either exo-skeletal substitutions at boron atoms with bridging and nonbridging groups or by influence of endo-hedral replacement of four cage CH groups present in the parent cobalt bis(dicarbollide) ion by two isolobal sulfur groups. The substitutions can thus be utilized for an easy tuning of the electrochemical properties of these boron polyhedral ions and for optimizing their responses in two quite broad electrochemical windows. The former is found in the negative potential corresponding to the redox process on the central metal atom; the latter, which was not considered in the literature, is located in the positive potential region and is connected with core cage oxidation process. Such properties seem to provide promising potential for electroanalytical sensing of this family of heterometallaboranes in tissues and their use for electrolabelling of biopolymers. (C) 2020 Elsevier Ltd. All rights reserved.