Influence of the Co(III) porphyrinates structure on the electrochemical and sorption properties of the ion-selective membranes based on them

Abstract

The influence of the electronic and steric effects of the p-OCH3, p-Cl, and o-NHCOC(CH3)3 substituents in the phenyl rings of Co(III) tetraphenylporphyrinates as well as that of the introduction of the axial nitrogen-containing ligand (dodecylimidazole) on the anionic selectivity of the membranes has been studied. It has been stated that the substitution at the phenyl cycles of the porphyrin had no significant influence on the anionic selectivity of the membrane, whereas the introduction of the axial nitrogen-containing ligand reduced the membrane specificity, the selectivity series approaching the classical Hofmeister series. All the studied electrodes have exhibited the enhanced (as compared to the Hofmeister series) selectivity towards nitrite, hydrocarbonate, and hydrophosphate anions.