Theoretical Investigation of Adsorption of Eugenol and Methyleugenol on the Coronene Surface: A Simplified Finite Molecular Model of Graphene

Abstract Graphene-based materials have attracted considerable interest for molecular adsorption, chemical sensing, and protective applications because of their extended π-conjugated electronic structure and ability to interact with aromatic compounds. Herein, a comparative first-principles investigation was performed on the adsorption of eugenol (C10H12O2) and methyleugenol (C11H14O2) on coronene (C24H12), employed as a simplified finite molecular model of a local graphene-like surface. Density functional theory calculations were performed using the ωB97X-D3/6–31G(d) approach, complemented by alternative functionals and the def2-TZVPD basis set to assess basis-set effects and basis set superposition error (BSSE). Both molecules preferentially adopted parallel configurations relative to the coronene surface, with adsorption distances characteristic of physisorption. The uncorrected adsorption energies were −0.645 and −0.672 eV for eugenol and methyleugenol, respectively, whereas BSSE-corrected benchmark calculations with def2-TZVPD yielded values between −0.536 and −0.593 eV. Energy decomposition analysis (EDA) identified dispersion as the dominant stabilizing contribution, followed by electrostatic and orbital interactions. Charge-transfer, molecular electrostatic potential, frontier molecular orbital, and density-of-states analyses revealed weak electronic coupling and limited charge redistribution upon adsorption. Vibrational calculations showed no imaginary frequencies and only minor changes in IR and Raman features, supporting the stability and predominantly noncovalent character of the complexes. Overall, methylation of the phenolic hydroxyl group produced a small increase in adsorption strength within the coronene model without changing the same physisorption mechanism. These results provide molecular-level insights into phenylpropanoid interactions with graphene-like carbon surfaces.