Investigation of ion pairs in electrochemical ferrocene methanol –Ferrocenium methanol system in presence of supporting electrolyte

Abstract

Density functional theory (DFT) has been applied to consider ion pair formation in ferrocenium methanol and ferrocene methanol aqueous solutions in the presence of a supporting electrolyte. Based on DFT calculation, the free energy of all species is calculated to evaluation the equilibrium constant. Henry constant of electrochemical ion pair species has been calculated based on transfer Gibbs free energy and combination free energy. DFT calculation in water solvent has been extended to calculate electrode potential as a function of supporting electrolyte. Polarizable continuum model (PCM) is applied for calculating HOMO and LUMO orbitals for ferrocenium methanol - chloride ion pair. DFT-PCM calculation has been done to get chemical structure of ion pair and all electrochemical species. DFT-PCM calculation shows that ion pair reaction between ferrocenium methanol and Cl− ion is an exothermic process. Theoretical DFT calculation results regarding chemical bond length and standard electrical potential of ferrocenium methanol to ferrocene methanol versus standard hydrogen electrode are agreement to the experimental result.