Rusydi, Febdian and Boli, Lusia Silfia Pulo and Adilina, Indri Badria and Cahyanto, Wahyu Tri and Parker, Stewart F. and Oemry, Ferensa (2025) The Role of Noncovalent Interactions in the Infrared Spectra of Lignin Model Compounds: A DFT Study. Molecules, 30 (24). ISSN 09748938

Text (Article) jp-journals-10006-2856[1] (1).pdf Download (338kB)

Abstract

Noncovalent interactions are key to the stability of lignin dimers, the primary components of bio-oil. However, their specific influence on the infrared spectra remains poorly understood. Using dispersion-corrected density-functional theory (APFD/6-311++G(d,p)), we conducted a comparative analysis of the structures and infrared spectra of four lignin derivativesâ benzene, phenol, anisole, and guaiacolâ as monomers and dimers. Our study reveals that distinct vibrational shifts and newly emerging peaks observed in the calculated infrared spectra of the dimers can be attributed to the formation of ÏÂ·Â·Â·Ï and ÏÂ·Â·Â·Ï stacking, hydrogen bonding, attractive van der Waals, and steric repulsion interactions. We extended the study to 3,3â²-dimethoxy-1,1â²-biphenyl-2,2â²-diol, a guaiacyl moiety with a CâC linkage. The results indicate that the structure in which both guaiacol units adopt an antiâ syn conformation is more stableâ minimizing steric repulsion between hydroxyl groupsâ than configurations in which one guaiacol unit adopts either antiâ anti or gaucheâ anti conformation. These differences are clearly reflected in their distinctive infrared spectral signatures. © 2025 by the authors.

Actions (login required)

View Item