A DENSITY FUNCTIONAL THE THEORY STUDY OF SULFATED MONOLIGNOLS: P-COUMARIL AND CONIFERYL ALCOHOLS

In the present study, sulfated mono- and disubstituted monolignols (p-coumaril, coniferyl alcohols) were investigated by the density functional theory method (DFT/B3LYP) with a 6-311+G (d, p) basis set. New data on these compounds were obtained: optimal configuration, FTIR, H-1 and C-13 NMR spectra, electronegativity, electrophilicity index, softness HOMO-LUMO analysis and molecular electrostatic potential. The obtained theoretical FTIR and NMR spectra are in good agreement with the experimental data presented in the literature. Based on the results of the study of theoretical C-13 NMR spectra, it was shown the introduction of sulfate groups into monolignols shifts the chemical shift towards larger values. According to HOMO-LUMO analysis, the lowest energy gap corresponds to monosulfated coniferyl alcohol. The analysis of the molecular electrostatic potential evidences that the sulfated monolignols contain regions with both nucleophilic reactivity and electrophilic reactivity.