Differences in electronic properties of fluorinated and trifluoromethylated fullerenes revealed by their propensity for dianion formation

The cross sections for electron transfer from sodium to C(60)F(n) (-) and C(60)(CF(3))(n) (-) anions in 50-keV collisions as a function of the number of functional groups n are reported. There are clear differences between derivatives of fluorine and trifluoromethyl due to the different electron withdrawing properties of F and CF(3). The role of inductive effects and pi electron delocalization on the electron affinity is discussed, assuming a correlation between the cross section and the electron affinity of the anion.