ELECTRON-TRANSFER REACTIONS WITH BUCKMINSTERFULLERENE, C-60, IN THE GAS-PHASE

The fundamental process of electron transfer is viewed from the new perspective provided by recent gas-phase measurements of reactions that remove electrons from the C60 molecule or donate electrons to singly and multiply charged C60 cations. Experimental results are reviewed for the chemical ionization of C60 by Penning ionization with metastable rare-gas atoms, single-electron transfer to atomic or molecular ions, double ionization by electron transfer, electron detachment reactions with He.+ or Ne.+, and multiple ionization by multiple-electron transfer to multiply charged rare-gas cations. Also, experimental are reviewed for single-electron transfer to C60.+ and C60(2+); a model previously proposed for the potential energy profile of single-electron transfer to C60(2+) is included which argues in favour of a reaction barrier arising from the Coulombic repulsion between the single charged product ions of such a process. Results of measurements previously reported for single and double-electron transfer reactions with C60(.3+) are also summarized. The latter reactions are unprecedented in electron transfer research. Data for thermal electron transfer reactions with C60n+ (n greater-than-or-equal-to 4) are not available, but results are indicated for electron transfer from Cs to C60(4+) at high collision energies. Intramolecular electron transfer is briefly discussed for exohedral and endohedral cation adducts of metal atoms and C60, and of exohedral adducts of molecules and C60(2+). Finally, the occurrence of electron transfer involving C60 anions is briefly considered.