Correlation and prediction of the solubility of Buckminster-fullerene in organic solvents; estimation of some physicochemical properties

The solubilities of Buckminsterfullerene, C-60, in 20 organic solvents have been transformed into water-solvent partition coefficients and the latter, as log P values, analysed by the Abraham solvation equation. Our analysis indicates that a water solubility of 10(-18) mol dm(-3) is the optimum value. The solubilities can be transformed into air-solvent partitions, L, using optimum values of the saturated vapour concentration, 10(-24) mol dm(-3), and the air-water partition coefficient, 10(-6). A total of 41 log P and log L values were thus processed to obtain the Abraham solvation descriptors for C-60. It is shown that C-60 is dipolar/polarisable, has no hydrogen bond acidity, but is a slightly stronger hydrogen bond base than compounds such as acetophenone. The descriptors indicate that C-60 behaves rather like a polyalkene rather than an aromatic system. Various properties of C-60 can be predicted from the solvation descriptors; C-60 is very lipophilic, is distributed between blood and brain largely into the brain, and is taken up by plant matrices from the air or from water almost quantitatively.