Interactions between aromatic hydrocarbons and functionalized C60 fullerenes - insights from experimental data and molecular modelling

Understanding molecular interactions between organic compounds and carbon-based nanomaterials is crucial to the interpretation of phase transfer processes, both in technical applications and within the environment. There is, however, little information available on the interactions between organic compounds and C-60 fullerenes, in particular regarding the effects of functionalization. Experimental sorption isotherms and molecular modelling have therefore been used to systematically investigate how these interactions are affected by functionalization of the sorbate (using one, two and four ring aromatics, with -OH or -NH2 functional groups) and the sorbent (i.e., C-60 and C-60-OH). Functionalization of the sorbent, as well as hydroxyl- and amino-functionalization of the sorbate, had a significant effect on sorption. The enhanced sorption of hydroxyl- and amino-functionalized sorbates by C-60 may be due to an increased contribution from pi-pi electron donor-acceptor interactions. Additional hydrogen bond interactions with C-60-OH also appear to play an important role. Our results emphasize that the surface chemistry of C-60 is of critical importance to their interactions with organic compounds. The ageing of C-60 in technical applications, or in the environment, is therefore likely to significantly affect the molecular interactions, and hence sorption strength, for polar and non-polar organic compounds.