Over 150 solvents have been probed to dissolve light fullerenes, but with a quite moderate success. We uncover unusual mutual polarizability of C 60 fullerene and selected room-temperature ionic liquids (RTILs), which can be applied in numerous applications, e.g. to significantly promote solubility/miscibility of highly hydrophobic C 60 molecule. We report electron density and molecular dynamics analysis supported by the state-of-the-art hybrid density functional theory and empirical simulations with a specifically refined potential.The analysis suggests a workability of the proposed scheme and opens a new direction to obtain well-dispersed fullerene containing systems. A range of common molecular solvents and novel ionic solvents are compared to 1-butyl-3-methylimidazolium tetrafluoroborate.

a b s t r a c tStructural and energetic aspects of solvation of fullerene C 60 in ionic liquids at room temperature were analyzed by using atomistic molecular dynamics simulations. Ethylammonium Nitrate (EAN) and 1-Butyl-3-Methylimidazolium Tetrafluoroborate (BMIMBF4) ionic liquids were conveniently chosen for presenting different polarities. Analysis of the spatial distribution of the ionic liquid revealed different patterns for the solvation of C 60 . Energetics indicated that the presence of C 60 weakened the ionic interactions in solution compared to those in pure liquids. Our free energy calculations showed that there is an energy cost of 235 kJ mol À1 for transferring fullerene C 60 from BMIMBF4 to EAN.

Diverse atomistic parameters of C60 have been developed and utilized to simulate fullerene solutions in biological environments. However, no thermodynamic assessment and validation of these parameters have been so far realized. Here, we employ extensive molecular dynamics simulations with the thermodynamic integration method in the isothermal-isobaric ensemble to investigate the transfer of a single fullerene C60 between different solvent environments using different potential models. A detailed analysis is performed on the structure and standard Gibbs free energy of transfer of C60 from benzene to ethanol. All of the interactions concerned in the transfer process are included via atomistic models. We notice that having only structural and dynamical properties is not decisive to validate reliable atomic parameters capable of describing a more realistic thermodynamic process. Thus, we employ the calculated free energy of transfer to validate more accurate atomic parameters for the solvation thermodynamics of fullerenes by direct comparison with the solubility experimental data.

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Atomistic molecular dynamics simulations were employed to investigate the solvation properties of the fullerene C60 in binary water/dimethyl sulfoxide (DMSO) mixtures. Structural analysis indicates a preferential solvation with the predominance of DMSO molecules in the first solvation shell for the solutions with low concentrations of DMSO. PMF calculations indicate a maximization of the hydrophobic interaction at low concentrations of DMSO. The contact minima indicate a tendency of aggregation of these nanostructures in water/DMSO mixtures and in the both pure solvents. The free energy of solvation suggests that the hydrophobicity of the fullerene increases monotonically with the increase of DMSO concentration. This result is incompatible with the polarity of DMSO, since it was expected that increasing the concentration of DMSO entailed an increase of C60 solubility.