Study on the Intramolecular Hydrogen Bonds of Dibenzofurans, Xanthones and Anthraquinones with One or Two Positions Substituted by Hydroxyls

摘要

The thermodynamic properties of dibenzofurans (DFs), xanthones (XTs) and an- thraquinones (AQs) with one and two positions substituted with hydroxyls in the ideal gas state at 298.15 K and 1.013×10~5 pa were calculated at the B3LYP/6-311G~* level using Gaussian 03 program. The isodesmic reactions were designed to calculate the standard free energy of formation (Δ_fG^e). Three types of hydrogen bonds exist in the three kinds of chemicals and their bond energies were ascertained as 7-15, 15-23 and 49-58 kJ·mol^(-1) respectively by comparing the Δ_fG^e values. Electronic density topology analysis was applied to validate the strength of bond.