Ab initio calculations of tautomer equilibrium and protonation enthalpy of 2-amino-2-oxazoline in the gas phase: basis set and correlation effects

Abstract

Ab initio calculations are performed to evaluate molecular properties of the two tautomeric forms of 2-amino-2-oxazoline and the protonated form with extended basis set at Hartree–Fock, Møller–Plesset perturbation (MP2) and density functional (BLYP, B3LYP) levels. Optimized geometries, atomic charge distributions, dipole moments, energies, tautomer equilibrium constant and protonation enthalpy are carefully analysed. The results obtained at different computational levels are compared to highlight the effects of basis set and correlation.