Document Type : Regular Article
Department of Chemistry, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran
DFT calculations was applied for modelling ascorbic acid in three homologous sulfoxides solvents including methyl, ethyl, and propyl groups using 6-31++G** basis sets in B3LYP level. NBO analysis was performed to evaluate Mulliken charge, electron donor and acceptor in AA/DRSO system. Vibrational analysis was evaluated by Gaussview package for the normal modes and hydrogen bonds between hydroxyl groups of AA and sulfoxide group in the solvent.
Our calculation showed that DFT/B3LYP method with 6-31++G** basis set is good candidate for quantum calculation of AA/DRSO systems. It was found that the most changes of the bond length were obtained in the interaction region between AA and the solvent, especially hydrogen bonds between oxygen of S=O group of sulfoxide and hydroxyl groups located on lactan ring. Charge analysis indicated that the positive charge of sulphur decreases by increase of alkyl group. Charge transfer (q) and polarity of S=O bond in DESO were higher than the other solvents. Vibrational analysis showed that the strongest hydrogen bond is formed in AA/DESO system.