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The primary steps in excited-state hydrogen transfer: the phototautomerization of o-nitrobenzyl derivatives.

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Publication date 2013
Author Šolomek Tomáš, Bochet Christian G, Bally Thomas,
Project Photons in organic synthesis
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Original article (peer-reviewed)

Journal Chemistry (Weinheim an der Bergstrasse, Germany)
Volume (Issue) 20(26)
Page(s) 8062 - 7
Title of proceedings Chemistry (Weinheim an der Bergstrasse, Germany)
DOI 10.1002/chem.201303338


The quantum yield for the release of leaving groups from o-nitrobenzyl "caged" compounds varies greatly with the nature of these leaving groups, for reasons that have never been well understood. We found that the barriers for the primary hydrogen-atom transfer step and the efficient nonradiative processes on the excited singlet and triplet surfaces determine the quantum yields. The excited-state barriers decrease when the exothermicity of the photoreaction increases, in accord with Bell-Evans-Polanyi principle, a tool that has never been applied to a nonadiabatic photoreaction. We further introduce a simple ground-state predictor, the radical-stabilization energy, which correlates with the computed excited-state barriers and reaction energies, and that might be used to design new and more efficient photochemical processes.