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

Electrochemistry of Cobalta Bis(dicarbollide) Ions Substituted at Carbon Atoms with Hydrophilic Alkylhydroxy and Carboxy Groups

“…For the structural formulae, please see Figure 1. In contrast to our previous results obtained with metallacarboranes and their exo-skeletal derivatives [44], all exoskeletal substituents used in this study were bound to the carborane cage at the carbon atom (previously only at the boron atom). Our aim was to determine to what extent the presence and position of a hydrophilic substituent can alter the electrochemical behavior of metallacarborane derivatives.…”

“…For higher concentrations, sigmoidal types of dependence are generally observed at the positive potential area of the polyhedral carborane cage oxidation; for higher sample concentrations, the signal does not increase linearly. This behavior has already been observed in other metallacarboranes [44]. Based on current and previous results we can assume that these effects may originate in the tendency of the metallacarborane anions to aggregate in aqueous solution.…”

“…If the CoSAN is considered as a template, we can observe one main broad peak situated at E = +1.32 V. Focusing on the negative potential, a small shoulder can be observed. Moving up to positive potentials, one overlapping peak appears at a potential of around E = +1.45 V, which is near to the potential of the electrode-electrolyte surface reaction [44] atoms in given rotamers. Coming out from our previously published results on metallacarboranes and their exo-skeletal derivatives [44,56] and newly obtained knowledge, we can assume that higher potential shift and/or the emergence of new peaks strongly depends on the physicochemical properties of the exo-skeletal substituents.…”

Structurally rigidified cobalt bis(dicarbollide) derivatives, a chiral platform for labelling of biomolecules and new materials

“…Stereochemical complications may in turn arise as a consequence of intermolecular interactions with various platforms, biological targets and surfaces. This effect is manifested in, for example, complicated discrimination of enantiomers that do not contain a rotational restriction group, by HPLC using cyclodextrin chiral stationary phases (CSPs), 29 splitting the electrode signals into several peaks in electrochemistry, 30 or by the presence of two observed orientations of the auxiliary substituent in the X-ray structures of CAIX–inhibitor complexes. 22 For some stereo-sensitive applications, the presence of one single conformer (rotamer) might be advantageous.…”

“…1,3,28,31 Considering electrochemistry, the presence of a short oxygen bridge between both boron positions results in a high and sharp signal, which does not interfere with the typical interval of potentials observed for biomolecules. 30 This compound can thus be considered as a good candidate for the electrolabelling of DNA and peptides provided that sufficiently reactive structural blocks are accessible.…”