The concerted transfer of one electron and one proton is a fundamental chemical process. Often the e– and H+ transfer together from one reagent to another, which is typically called hydrogen atom transfer, but it can also occur with substantial separation of the e– and H+. This presentation will describe a number of different types of such multiple-site PCET processes. For example, the ruthenium-bipyridine complexes with a distant carboxylic acid shown here (n = 0 or 1) react readily with reagents such as the nitroxyl radical TEMPO despite the up to 11 Å separation of the proton from the ruthenium center. The dependence of the rate constants on the e–/H+ coupling will be discussed, including in related termolecular reactions. A unimolecular photo-induced system has also been developed, coupling a phenol-base to a photoexcitable anthracene as shown below. This system allows studies of very rapid PCET process from high to very low temperatures. The results will be interpreted using versions of Marcus theory to give insight into this important class of reactions.

Concerted multiple-site proton-coupled electron transfer (PCET): Effects of separating the proton and electron

249th National Meeting (2015)

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