title: DFT study and Monte Carlo simulation on proton transfers of 2-amino-2-oxazoline, 2-amino-2-thiazoline, and 2-amino-2-imidazoline in the gas phase and in water.
abstract: Density functional theory (DFT) and Monte Carlo (MC) simulation with free energy perturbation (FEP) techniques have been used to study the tautomeric proton transfer reaction of 2-amino-2-oxazoline, 2-amino-2-thiazoline, and 2-amino-2-imidazoline in the gas phase and in water. Two reaction pathways were considered: the direct and water-assisted transfers. The optimized structures and thermodynamic properties of stationary points for the title reaction system in the gas phase were calculated at the B3LYP/6-311+G(d, p) level of theory. The potential energy profiles along the minimum energy path in the gas phase and in water were obtained. The study of the solvent effect of water on the proton transfer of 2-amino-2-oxozoline, 2-amino-2-thiazoline, and 2-amino-2-imidazoline indicates that water as a solvent is favorable for the water-assisted process and slows down the rate of the direct transfer pathway.
authors.affiliation: College of Chemistry, Key Lab of Green Chemistry and Technology in Ministry of Education, Sichuan University, Chengdu, 610064, People's Republic of China. xueyingscu@163.com
authors.forename: Ying
authors.initials: Y
authors.lastname: Xue
authors.forename: Chan Kyung
authors.initials: CK
authors.lastname: Kim
authors.forename: Yong
authors.initials: Y
authors.lastname: Guo
authors.forename: Dai Qian
authors.initials: DQ
authors.lastname: Xie
authors.forename: Guo Sen
authors.initials: GS
authors.lastname: Yan