Abstract
The study of electron transfer (ET) at the oil (O)/water (W) interface is useful for understanding energy conversion processes occurring at biomembranes. The recent introduction of SECM (scanning electrochemical microscopy) as well as other new methods to this field has revitalized the study of the reaction mechanism of ET at the O/W interface. However, the mechanism is not necessarily simple, and often involves an ion-transfer process. When a not very hydrophobic complex such as ferrocene (Fc) is used for the redox species in the O phase, the ET would occur homogeneously in the W phase, the interfacial transfer of the ionic product (e.g., Fc+) being responsible for the current flowing through the interface. On the other hand, when an extremely hydrophobic complex such as lutetium bihthalocyanine is used, the heterogeneous, i.e., true ET should occur at the O/W interface. Marcus proposed a general kinetic equation for the heterogeneous ET. There are some experimental data which support the Marcus theory, however, further careful and detailed studies seem to be required. In this review, recent developments in theory and methodology in this research field are described.
