Electron Transfer Reactions

Abstract

This chapter presents that electron transfer plays an important role in many physical, chemical and biological processes. Biological processes involve a series of reactions that are effectively controlled by electron transfer. Electron transfer reactions occur on a timescale of femtoseconds to seconds and over distances of less than 0.1 nm to about l.0 nm. Technologically important processes like redox catalysis, solar energy conversion, non-linear optics, and information storage devices provide a few examples of areas where electron transfer is important. Studies of redox reactions involving transition metals in solution have established that there are basically two types of mechanisms for electron transfer: (1) outer sphere and (2) inner sphere mechanisms. In addition to that distinction, redox reactions are divided into self exchange reactions between two different oxidation states of the same metal ion and redox reactions between complexes with different metal centers. In the following sections, the mechanisms of these reactions will be discussed in conjunction with a discussion of the factors that influence the rates of redox reactions.