Cobaltabisdicarbollide anion [Co(C₂B₉H₁₁)₂]^- as doping agent on intelligent membranes for ion capture

It has been proven that the non-nucleophilic, low charge density and weakly coordinating cobaltabisdicarbollide anion [Co(C₂B₉H₁₁)₂]^- , can be highly relevant as dopant for conducting organic polymers. We have developed a new material based on polypyrrole (PPy) which uses the cobaltabisdicarbollide anion as a doping agent. This anion provides enhanced properties to PPy, the most striking one is the high over oxidation resistance. The high volume of [Co(C₂B₉H₁₁)₂]^- imposes low mobility inside the polymeric matrix thus preventing dopant leakage when a reducing potential is applied on the material. Under these conditions the cation capture (Eq. 1) prevails during the reversible electrochemical redox process, also called doping-undoping. [PPyⁿ⁺(A^-)_n]+ nC⁺ charge-discharge process show an almost perfect reversibility of cation exchange process and no detectable degradation of the membrane due to dopant loss or over oxidation even after 40 successive cycles.