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Electron-proton free-energy surfaces for proton transfer reaction in polar solvents: test calculations for carbon-carbon reaction centresстатья
Информация о цитировании статьи получена из
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Web of Science
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 8 сентября 2021 г.
- Авторы: Basilevsky M.V., Soudackov A.V., Vener M.V.
- Журнал: Chemical Physics
- Том: 200
- Номер: 1-2
- Год издания: 1995
- Издательство: Elsevier BV
- Местоположение издательства: Netherlands
- Первая страница: 87
- Последняя страница: 106
- DOI: 10.1016/0301-0104(95)00227-f
- Аннотация: The proton transfer reaction R− + HR → RH + R− of benzyl-type compounds in a polar solvent has been studied theoretically in terms of a proton adiabatic dynamical treatment of a mixed quantum-classical reacting system. The gas phase potentials were obtained using the PM3 method and then approximated by appropriate (LEPS type) quasi-analytical functions. Polar medium degrees of freedom were introduced, similar to the Marcus electron transfer theory, in terms of a two-state electronic Hamiltonian. At this level, three-dimensional free energy surfaces were obtained, including a pair of intrasolute coordinates, the CH stretch and heavy-atom vibrational mode of the reaction centre, together with the collective medium polarization mode. At the next stage, two-dimensional electron-proton free energy surfaces (EP FESs) corresponding to the adiabatic approximation with respect to CH stretch were generated for the two lowest proton levels. Their main features are described. The reaction with R = benzyl proved to be proton-adiabatic. Its rate constant transmission factor calculated in terms of the Kramers-Grote-Hynes theory is significantly less than unity (∼0.4–0.6) because the reaction coordinate at the transition state of the ground state EP FES coincides with the medium mode. The reaction with R = fluorenyl does not obey the proton-adiabaticity condition and needs a special kinetic treatment. A remarkable observation is that the double adiabatic electron-proton approximation is incapable of providing sufficiently high classical barriers (> 10 kcal/mol) on ground-state two-dimensional EP FESs for proton transfer reactions in polar solvents.
- Добавил в систему: Венер Михаил Владимирович