Prototropic tautomerism of imidazolone in aqueous solution: a density functional approach using the combined discrete/self-consistent reaction field (SCRF) models.
A systematic investigation of the proton transfer in the keto-amino/enol tautomerization of imidazolone was undertaken. Calculations in aqueous solution were performed using both combined discrete/self-consistent reaction field (SCRF) and SCRF methods. Complexes containing one to three water molecules around the hydrophilic site of imidazolone were used for the combined discrete/SCRF calculations. The DFT results predict that the barrier height for non-water-assisted intramolecular proton transfer is very high (214.8 kJmol(-1)). Hydrogen bonding between imidazolone and the water molecule(s) will dramatically lower the barrier by a concerted multiple proton transfer mechanism. The proton transfer process through a eight-member ring formed by imidazolone and two water molecules is found to be more efficient and the calculated barrier height is ca. 61 kJmol(-1).
Ren
Yi
Y
School of chemistry of chemical engineering, Southwest China Normal University, Chongqing, 400715, People's Republic of China. yiren57@hotmail.com
Li
Ming
M
Wong
Ning-Bew
NB
D006860:Hydrogen Bonding; D007093:Imidazoles / Q000737:chemistry*; D007700:Kinetics; D008956:Models, Chemical; D008958:Models, Molecular; D011522:Protons; D012996:Solutions; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
D007093:Imidazoles; D011522:Protons; D012996:Solutions; C117197:imidazolone; D014867:Water
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