title: Allylic H-Abstraction Mechanism:  The Potential Energy Surface of the Reaction of Propene with OH Radical.
abstract: The allylic H-atom abstraction reaction plays a more dominant role, especially at lower temperature, than addition reactions in the case of the CH2 [Formula: see text] CH-CH3 + •OH system. Different computational methods including ab initio as well as density functional methods have been used to examine allylic H-abstraction. Both the energetically less favorable direct H-abstraction and the more favorable indirect H-abstractions have been investigated. Using first principles computations, for the indirect abstraction, a stable π- or reactantlike as well as a late productlike complex were found on the potential energy surface. Based on higher level single point calculations (QCISD(T)/6-311+G(3df,2p)), a new activation enthalpy value, Δ(⧧)H° = 0.3 ± 2 kJ/mol, is suggested for the title reaction. The computed reaction enthalpy ΔrH° = -124.7 ± 2 kJ/mol is in good agreement with the experimental value. The stability of the initial π-complex was found to be ΔH°π-complex = -7.1 kJ/mol. The product complex between the transition state and the product was found with the stability of -127.2 kJ/mol.
authors.affiliation: Department of Chemistry and Chemical Informatics, Faculty of Education, University of Szeged, Szeged, Boldogasszony sgt. 6, Hungary 6725, PhysicoChimie des Processus de Combustion et de l'Atmosphère - UMR 8522, Centre d'Etudes et de Recherches Lasers et Applications Université de Lille 1, F-59655 Villeneuve d'Ascq, Cedex, France, and Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6.
authors.forename: Milan
authors.initials: M
authors.lastname: Szori
authors.affiliation: Department of Chemistry and Chemical Informatics, Faculty of Education, University of Szeged, Szeged, Boldogasszony sgt. 6, Hungary 6725, PhysicoChimie des Processus de Combustion et de l'Atmosphère - UMR 8522, Centre d'Etudes et de Recherches Lasers et Applications Université de Lille 1, F-59655 Villeneuve d'Ascq, Cedex, France, and Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6.
authors.forename: Christa
authors.initials: C
authors.lastname: Fittschen
authors.affiliation: Department of Chemistry and Chemical Informatics, Faculty of Education, University of Szeged, Szeged, Boldogasszony sgt. 6, Hungary 6725, PhysicoChimie des Processus de Combustion et de l'Atmosphère - UMR 8522, Centre d'Etudes et de Recherches Lasers et Applications Université de Lille 1, F-59655 Villeneuve d'Ascq, Cedex, France, and Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6.
authors.forename: Imre G
authors.initials: IG
authors.lastname: Csizmadia
authors.affiliation: Department of Chemistry and Chemical Informatics, Faculty of Education, University of Szeged, Szeged, Boldogasszony sgt. 6, Hungary 6725, PhysicoChimie des Processus de Combustion et de l'Atmosphère - UMR 8522, Centre d'Etudes et de Recherches Lasers et Applications Université de Lille 1, F-59655 Villeneuve d'Ascq, Cedex, France, and Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6.
authors.forename: Bela
authors.initials: B
authors.lastname: Viskolcz