Theoretical Study on the Solvation of C₆₀ Fullerene by Ionic Liquids II: DFT Analysis of the Interaction Mechanism

Abstract

As a continuation of our previous work (<i>J. Phys. Chem. B</i>, <b>2014</b>, <i>118</i>, 11330) on the solvation of C₆₀ by ionic liquids (ILs) using Molecular Dynamic simulations, this paper reports a systematic density functional theory (DFT) analysis on the interaction mechanism between C₆₀ and 24 different ionic liquids (belonging to the imidazolium, piperazinium, and cholinium groups). Properties such as binding energies, charge distributions, intermolecular interactions, or electronic structure were analyzed as a function of the selected ILs. The stronger IL-C₆₀ interactions would be related with π–π stacking between the C₆₀ surface and anions such as salycilate ([SA]). Likewise, the electronic structure analysis pointed to a well-defined relationship between the energetics of IL-C₆₀ systems and IL features. Therefore, ILs with deep HOMO energies as well as weak interaction between both ions would be a priori good candidates for C₆₀ solvation. Although only short-range interactions are studied in the framework of DFT, this work provides useful information for the rational design of ILs that could exhibit suitable features as C₆₀ solvents