Hydrogen Bonding and Density Functional Calculations: The B3LYP Approach as the Shortest Way to MP2 Results

Abstract

As a test for the applicability of the density functional theory to the system containing intramolecular hydrogen bonds, calculations were performed on propen-1,2,3-triol, the feasible intermediate in the epimerization of dihydroxyacetone and glyceraldehyde enantiomers. A comparison is made between results obtained by Becke's three parameter hybrid functional (for exchange) with gradient corrections provided by the LYP correlation functional (B3LYP) and those predicted at the ab initio Møller−Plesset second-order (MP2) level. The calculated minimum energy structures are in excellent agreement with respect to both energy and geometries of hydrogen-bonded structures. Earlier and recent studies suggest that, generally, the nonlocal B3LYP approximation leads to a very accurate overall description of intramolecular hydrogen-bonded systems. We propose a new, more efficient computational protocol, which may be useful in the study of the biologically important molecules at a level of accuracy usually only provided by traditional post-Hartree−Fock ab initio methods.