title: A Theoretical Study of Ene Reactions in Solution: A Solution-Phase Translational Entropy Model.
abstract: Several density functional theory (DFT) methods, such as CAM-B3LYP, M06, ωB97x, and ωB97xD, are used to characterize a range of ene reactions. The Gibbs free energy, activation enthalpy, and entropy are calculated with both the gas- and solution-phase translational entropy; the results obtained from the solution-phase translational entropies are quite close to the experimental measurements, whereas the gas-phase translational entropies do not perform well. For ene reactions between the enophile propanedioic acid (2-oxo-1,3-dimethyl ester) and π donors, the two-solvent-involved explicit+implicit model can be employed to obtain accurate activation entropies and free-energy barriers, because the interaction between the carbonyl oxygen atom and the solvent in the transition state is strengthened with the formation of C-C and O-H bonds. In contrast, an implicit solvent model is adequate to calculate activation entropies and free-energy barriers for the corresponding reactions of the enophile 4-phenyl-1,2,4-triazoline-3,5-dione.
authors.affiliation: College of Chemistry, Beijing Normal University, Beijing, 100875, P.R. China.
authors.forename: Liu
authors.initials: L
authors.lastname: Zhao
authors.affiliation: College of Chemistry, Beijing Normal University, Beijing, 100875, P.R. China.
authors.forename: Shi-Jun
authors.initials: SJ
authors.lastname: Li
authors.affiliation: College of Chemistry, Beijing Normal University, Beijing, 100875, P.R. China. dcfang@bnu.edu.cn.
authors.forename: De-Cai
authors.initials: DC
authors.lastname: Fang
keywords: density functional calculations; ene reaction; reaction mechanisms; solvent effects; thermodynamics