Significant effect of charge microenvironment on the redox potential of [Fe4Se4(SPh)4]2− in solution and inside film

Abstract

Through this work, we have shown that both the nature and the compactness of charge of the microenvironment around the [Fe4Se4(SPh)4]2−/3− couple are important in determining its redox potential. The redox potential of the [Fe4Se4(SPh)4]2−/3− couple has been measured in pure dimethylformamide (DMF), DMF added with surfactants of different charges, and also in positive surfactant film on an electrode surface. The redox potential becomes 0.090 V positive when the solution microenvironment is made positive compared to that in DMF. On the other hand, if the microenvironment is made positive and static (in the form of a positive film), the positive shift in the potential is 0.265 V, and compactness of charge induced an extra 0.175 V positive shift in the potential.