Kinetics of IrCl₆ ^2- ion transfer across the water/ 1,2-dichloroethane interface and the effect of a phospholipid monolayer

IrCl₆^2- ion transfer (IT) across a native water/1,2-dichloroethane (DCE) interface has been investigated using microelectrode measurements at expanding droplets and scanning electrochemical microscopy (SECM). The interfacial potential drop was controlled by ClO₄^- ion in each phase, which also maintained charge neutrality during IrCl₆^2- IT. IrCl₆^2- transferred across the interface with an apparent transfer coefficient of 0.63 ± 0.05. SECM-double potential step chronoamperometry was used to study the effect of L-α-phosphatidylethanolamine, dilauroyl on the transfer of IrCl₆^2- from water to the DCE phase. The phospholipid was found to significantly diminish the rate of IT, with the retardation effect dependent on the interfacial phospholipid concentration. Kinetic data obtained from these studies were successfully explained using a simple energy barrier model.