Analysis of intermolecular interactions of n-perfluoroalkanes with circumcoronene using dispersion-corrected DFT calculations: comparison with those of n-alkanes. Issue 16 (4th April 2023)

• Record Type: Journal Article
• Authors: Kikkawa, Yoshihiro; Tsuzuki, Seiji
• Is Part Of: Physical chemistry chemical physics. Volume 25:Issue 16(2023)
• Page Start: 11331
• Page End: 11337
• Publication Date: 2023-04-04
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/d3cp00790a
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : Dispersion-corrected DFT calculations quantitatively revealed the interactions of n -alkanes and n -perfluoroalkanes with circumcoronene as the models of molecular adsorption on graphite. Abstract : Understanding the interactions between the adsorbate and substrate is critical in basic and advanced scientific fields, including the formation of well-organised nanoarchitectures via self-assembly on surfaces. In this study, the interactions of n -alkanes and n -perfluoroalkanes with circumcoronene were studied using dispersion-corrected density functional theory calculations as models of their adsorption on graphite. The interactions of n -perfluoroalkanes with circumcoronene were significantly weaker than those of the corresponding n -alkanes, e.g. the calculated adsorption energies of n -perfluorohexane and n -hexane were −9.05 and −13.06 kcal mol −1, respectively. The dispersion interactions were the major source of attraction between circumcoronene and the adsorbed molecules. Larger steric repulsion of n -perfluoroalkanes compared to those of n -alkanes increased their equilibrium distances from circumcoronene and decreased the dispersion interactions, resulting in weaker interactions. The interactions between two adsorbed n -perfluorohexane molecules and those of n -hexane molecules were −2.96 and −2.98 kcal mol −1, respectively, which are not negligible in the stabilisation of adsorbed molecules. The geometries of adsorbed n -perfluoroalkane dimers revealed that the equilibrium distance between two n -perfluoroalkane molecules did not match the width of the six-membered rings in circumcoronene, in contrast to that between n -alkanes. The lattice mismatch also destabilised the adsorbed n -perfluoroalkane dimers. The difference in the adsorption energy between flat-on and edge-on orientations of n -perfluorohexane was smaller than that of corresponding n -hexane.