Facilitated ion transfer across the water/nitrobenzene interface Theory for single-scan voltammetry applied to a reversible system

The transfer of the metal cation across the interface between two immiscible electrolyte solutions facilitated by complex formation with a ligand at the interface was investigated both theoretically and experimentally. The theory of single-scan voltammetry was derived which enables the complex stoichiometry (1:1, 1:2 or 1:3. cation to ligand) to be determined as well as the thermodynamic and transport parameters of the facilitated charge transfer controlled by the diffusion of the ligand. Application of the theoretical results was illustrated for the transfer of Li⁺ and Cd²⁺ ions across the water/nitrobenzene interface facilitated by complexation with the neutral macrocyclic polyether diamine.