Kinetics and mechanism of the dissociative reduction of C-X and X-X bonds (X = O, S)

This chapter discusses some recent developments and methodologies that have impacted the understanding of dissociative electron transfer (ET). It focuses on the reduction of C–X and X–X bonds in which X is either oxygen or sulfur and provides insights into the nature of the intrinsic barriers for the stepwise dissociative reduction reactions as well as some interesting examples that demonstrate a need to continue to develop the present dissociative ET model. The reduction of ethers, peroxides, sulfides, and disulfides presented also provides some insights into the three-surface and two-surface models of transition from the stepwise to the concerted mechanisms. The combination of electrochemical data with other kinetic or thermodynamic approaches provides independent confirmation of the kinetic and thermodynamic data and allows the kinetic window to be extended both for highly exergonic and highly endergonic processes. It is significant to ensure that the kinetics is in the activation region in the assessment of intrinsic barriers. © 2001, Elsevier Inc. All rights reserved.