ABSTRACT
The coupling between electron transfer and bond breaking between two heavy atoms occurs in a large number of biochemical and chemical processes, such as cleavage of C-halogen bonds in organic halides as well as other bonds [1-4], electron transfer activation of small molecules involved in contemporary energy challenges (e.g., O2 and CO2), as well as enzymatic reactions like dechlorination processes of RCl toxic derivatives within reductive dehalogenases [5]. In all of these reactions, the bond breaking accompanying electron transfer may be triggered in various ways, electrochemically, by homogeneous electron donors or acceptors, photochemically, or by means of pulse radiolysis [1-3]. The fact that so many chemical reactions can follow or accompany electron transfer is the basis of the synthetic value of electron transfer chemistry. Such processes also irrigate more applied šelds, for example, the area of sensors and biosensors, which both involve the transduction of the presence of a molecule into an electrochemical signal. Another, more prospective šeld, concerns molecular electronics, where the understanding of the structural changes coupled to charge transfer will be central in the design and working of devices including redox centers connected by molecular wires. The key reactivity paradigm in charge transferinduced bond breaking processes is the concerted/stepwise mechanistic dichotomy, as illustrated in Scheme 14.1 [1-3].
