Theoretical studies of proton-coupled electron transfer reactions.

A theoretical formulation for proton-coupled electron transfer (PCET) is described. This theory allows the calculation of rates and kinetic isotope effects and provides insight into the underlying fundamental principles of PCET reactions. Applications of this theory to PCET reactions in iron bi-imidazoline complexes, oxoruthenium polypyridyl complexes, osmium-benzoquinone systems, amidinium-carboxylate salt bridges, DNA-acrylamide complexes, and ruthenium polypyridyl-tyrosine systems are summarized. The mechanistic insight gained from theoretical calculations on these model systems is relevant to PCET in more complex biological processes such as photosynthesis and respiration.