Physisorption of benzene on cation/silica clusters via cation–π interactions: Theoretical study

Abstract

Interactions of a benzene molecule with four different silica clusters decorated with mono- and divalent cations (Li⁺, Na⁺, Mg²⁺) have been theoretically studied. By means of SAPT0 calculations, we have analyzed the changes in the energy components in dependence of hydrophobic or hydrophilic positions of adsorption, the size of the cluster studied or the cation used for the ’decoration’. It was found that adsorption of benzene on pristine silica clusters is mainly driven by electrostatic (∼37–43 %) and dispersion (∼37–55 %) forces. At the same time, cation–π interactions can be accounted for by significant electrostatic (∼20–50 %) and induction (∼24–54 %) energy terms. IGM analysis reveals the existence of cation–π and van der Waals interactions. The significant binding of benzene to the decorated silica surface (up to ∼ − 19.97, −29.63, − 93.82 kcal/mol for Na⁺, Li⁺, Mg²⁺, respectively) can pave a way for the sorption of a typical organic contaminant.