The scope of organic photochemistry has been significantly broadened through reactions that proceed via electron transfer. The dynamics of radical ion pairs (contact and solvent-separated) and the factors that control their radiative and nonradiative decay provided a framework to design efficient photoinduced electron transfer reactions. Investigating these reactions relied on the combined use of several transient and steady state kinetics. Current interest is on electron transfer reactions that take place only when coupled with a chemical transformation (e.g., bond cleavage, bond formation or proton transfer). Careful examination of several reactions revealed that these bond-coupled electron transfer reactions (uni-, bi-, and ter-molecular) are not uncommon. A second theme of the current research is on quantum amplification. Very high quantum yields were achieved in complex chain reactions involving free radicals that proceed via electron transfer, as well as those propagated via adiabatic reactions in the triplet state.
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