Study of the structure, the electronic and spectral properties of D-glucaro-dilactones

Abstract The double lactonization of D-glucaric acid can result in two isomeric molecules which are: the D-glucaro-1,4:6,3-dilactone and the D-glucaro-1,5:6,3-dilactone. In the present article we try to understand the differences between these molecules. To this end, all the conformations have been modeled and optimized in order to find the most stable structures. Energies, frontier orbitals (HOMO and LUMO) as well as other electronic and spectral properties have been calculated in vacuum, acidic and aqueous media using the polarizable continuum model (PCM). The calculations were investigated by performing semi-empirical PM6 and density functional theory (DFT) at the B3LYP level of theory. The obtained results do not motivate a possible observation of the two dilactones simultaneously in the same medium, which explains the absence of this coexistence in the scientific works carried out to date.