Tautomerism equilibrium given in Fig. 1 shows that two keto-enol tautomerisms are possible for β-Dicarbonyls. The position of the keto-enol equilibrium for this class of compounds differs according to electronic characteristics of the substitution and the nature of the solvents. The cis-enol forms of β-dicarbonyl compounds are stabilized by a strong intramolecular hydrogen bond (IHB) with a double minimum character. The IHB of these compounds have been the subject of numerous investigations, which support the existence of a strong intramolecular hydrogen bond of chelating nature in the enol forms of β-dicarbonyl compounds [1–6]. The aim of the present paper is to predict IHB strength of 2,6-Dimethyl-3,5-heptanedione (DMHD) by means of density functional theory (DFT) levels and vibrational spectra.

Keywords