Features of Electron Transfer

Acknowledgments. This work has been supported by USPHS Grants No. GM20530 and GM31611. 

Ackrell, B. A. C., Cochran, B., and Cecchini, G., 1989, Interactions of oxaloacetate with Escherichia coli fiimarate reductase. Arch. Biochem. Biophys. 268 26n34. 

Backes, W. L., and Reker-Backes, C. E., 1988, The effect of NADPH concentration on the reduction of cytochrome P-450 LM2. J. Biol. Chem. 263 247n253. 

Barher, M. J., Pollock, V., and Spence, J. T. (1988) Microcoulometric analysis of trimethylamine dehydrogenase., Biochem. J. 256 657n659. 

---

Many of the features of electron transfer reactions involving excited states can be understood based on electron transfer theory. 

In the second chapter, Appleby presents a detailed discussion and review in modem terms of a central aspect of electrochemistry Electron Transfer Reactions With and Without Ion Transfer. Electron transfer is the most fundamental aspect of most processes at electrode interfaces and is also involved intimately with the homogeneous chemistry of redox reactions in solutions. The subject has experienced controversial discussions of the role of solvational interactions in the processes of electron transfer at electrodes and in solution, especially in relation to the role of Inner-sphere versus Outer-sphere activation effects in the act of electron transfer. The author distils out the essential features of electron transfer processes in a tour de force treatment of all aspects of this important field in terms of models of the solvent (continuum and molecular), and of the activation process in the kinetics of electron transfer reactions, especially with respect to the applicability of the Franck-Condon principle to the time-scales of electron transfer and solvational excitation. Sections specially devoted to hydration of the proton and its heterogeneous transfer, coupled with... 

Our objective in this chapter is to familiarize organic chemists with fundamental electrochemical concepts that support several aspects of organic electrochemistry elaborated in this book, as well as many important features of electron transfer reactions. In fact, although the term electrochemistry evokes for most readers the idea of chemistry at electrodes, in our opinion electron transfer chemistry constitutes a better definition when organic or organo-metallic electrochemistry is concerned. This is particularly obvious when one thinks of an... 

Note that more sophisticated models have been proposed to take into account the nonspherical nature of reactant and products, the eventual distribution of charges on different centers within the molecule [55], the eventual coupling between the inner shell and solvent fluctuation modes, and other factors [56]. Yet the simplest model described here is sufficient for our purposes, since it includes most of the essential features of electron transfer reactions. 

This section presents phenomenological and theoretical features of mechanistically simple electrochemical processes in a parallel manner to the corresponding treatment for homogeneous electron transfer in 12.2.3. Discussion, therefore, will be limited to the elementary single-electron transfer process itself and restricted to thermal-electron transfer at metal-solution interfaces, although some aspects are common to all types of interfacial charge-transfer processes. Although narrow in scope, this approach serves to illustrate the relationship between, and the common features of, electron transfer at electrodes and in bulk solution. 

However, for most redox enzymes more elaborate electron-tranfer pathways have to be considered in biosensor design. As this problem is crucial for understanding amperometric biosensors, the following sections deal with the complex features of electron-transfer mechanisms and sensor architecture [53]. 

Ii is very rare in theoretical chemistry thax a many-dimensional problem can be transformed to a single variable problem. This is why the Marcus idea described above of a collective coordinate, provokes the reaction no way . However, as it turned out later, this simple postulate lead to a solution that grasps the essential features of electron transfer. 

---