Photoinduced Redox Reactions in Organic Synthesis
Photoexcitation, which renders well-defined redox potential differences between two interacting species, has become an increasingly useful tool in initiating electron-exchange processes and to generate radical ions: a new type of reactive intermediates, from neutral substrates. The importance of this concept in chemistry has grown rapidly during the last decade, and a subdiscipline known as photoinduced electron transfer (PET) appears to have emerged in the general arena of photochemistry. The most common reaction observed from radical cation species is either the loss of proton or the dissociation of relatively weaker bond with consequent formation of radicals and cations with lifetime and chemical affinities different from those of parent species. The chapter concludes with a note that the consequence of PET transformations from organic substrates may be characterized by evaluating the reactivity profiles of initially produced radical ions.