Wydział Chemii

Agata Martyniak

Jarosław Panek

Aneta Jezierska-Mazzarello

Aleksander Filarowski

2012

Journal of Computer-Aided Molecular Design

26

1045-1053

10.1007/s10822-012-9597-3

Naukowa

Angielski

Artykuł

First-principles Car-Parrinello molecular dynamics, ab initio (MP2) and density functional schemes have been used to explore the tautomeric equilibrium in three tris(amino(R)methylidene)cyclohexane-1,3,5-triones (R = hydrogen, methyl or phenyl group). The dynamic nature of the cyclic hydrogen bonding has been studied by the first-principles MD method. The comparison of the results obtained by aforesaid methods has been accomplished on the basis of calculations of structural and spectroscopic characteristics of the compounds. The conformational analysis of the studied compounds has been carried out at the MP2/6-31+G(d,p) and B3LYP/6-31+G(d,p) levels of theory. The influence of steric and electronic effects on the cyclic hydrogen bonding has been analysed. The extent of the proton delocalization has been modified by the substituents according to the sequence: hydrogen < phenyl < methyl. This fact is verified by the spectroscopic and structural data as well as the energy potential curve. A prevalence of the keto-enamine tautomeric form has been observed in the static ab initio and DFT models, and confirmed by the first-principles MD.

Circle hydrogen bonding formation, Schiff-base, Keto-enamine, Enol-imine, Tautomeric equilibrium, CPMD, MP2, DFT, Potential energy function, conformational analysis

http://dx.doi.org/10.1007/s10822-012-9597-3

http://link.springer.com