Mass spectrometry, photoelectron spectroscopy, and quantum chemical studies of fluorofullerene dianions

Singly and doubly charged anions of fluorofullerenes were produced by means of electrospray ionization from acetonitrile/dichlorobenzene solutions of C60F36 and C60F48 doped with organic electron donors. These anions can be formally viewed as products of mono- and bis-substitution of fluorine atoms by electrons. Photoelectron spectra of C60F342− and C60F462− allow estimating the second electron affinity of the corresponding neutral species to be 2.4 (1) and 3.2 (1) eV, respectively. Quantum chemical calculations at the DFT level of theory suggest that the observed dianions form due to fluorine rearrangements on the carbon shell, which is governed by their high relative stability.