The cyclic voltammetry of fullerene C-60 was examined in mixed benzonitrile/RTIL solvents in order to probe the effect of nanodomains in the mixed RTIL/benzonitrile solutions and their effect upon the voltammetry. In probing the interactions of the fullerides (up to C-60(3-)) with RTILs, BMIm(+) (1-butyl-3-methylimidazolium, mostly planar) and tetraalkylammonium (more spherical/flexible) salts were used. In order to investigate these shifts in more detail, the Delta E-12 degrees (=E-1 degrees-E-2 degrees) and Delta E-23 degrees (=E-2 degrees-E-3 degrees) values, which were independent of the reference potential, were used. At higher concentrations of the RTILs, greater stabilization of the more highly charged fullerides were observed. These shifts were attributed to the interaction of the fullerides with nanodomains of the RTIL. This was further confirmed by examining the shifts in the E-1/2 values of non-RTIL and RTIL salts at constant ionic strength and the changes in diffusion coefficient with %RTIL. The observed shifts in the E-1/2 values with increased concentration of the RTIL salts could not be explained by ion pairing equilibria alone. Changes in the visible and near infrared spectra between benzonitrile and mixed benzonitrile/RTIL spectra were most significant for C-60(3-), where voltammetric evidence indicates the strongest interaction between the fullerides and the RTIL. Among the RTILs studied, preliminary DFT calculations showed that the more flexible tetraalkylammonium ion was able to stabilize the C-60-anionic species better than the planar BMIm(+) species, under similar solution conditions. (C) 2016 Elsevier Ltd. All rights reserved.