Abstract
Radical ion pairs generated by photoinduced electron transfer may undergo return electron transfer (RET) in pairs of singlet or triplet multiplicity. RET efficiencies are determined by the free energy of RET and the topologies of the potential surfaces of parent molecule, radical ion and triplet state. If radical ion geometries are different from the corresponding triplet states, RET occurs either with cleavage (“dissociative” RET; 1,2-diphenylcyclopropane radical cations) or formation of C-C bonds (“associative” RET; norbornadiene radical cation). Radical ions of some strained ring compounds spontaneously undergo ring-opening; RET to such species form ring-opened triplets without major geometry changes. CIDNP spectroscopy offers unique insights into triplet RET.
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This paper was published as part of the themed issue in honour of Jakob Wirz.
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Roth, H.D. Biradicals by triplet recombination of radical ion pairs. Photochem Photobiol Sci 7, 540–546 (2008). https://doi.org/10.1039/b800524a
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DOI: https://doi.org/10.1039/b800524a