Electrochemical, ESR and theoretical studies of [6,6]-opened C(60)(CF(2)), cis-2-C(60)(CF(2))(2) and their anions.

Electrochemical behavior of C(60)(CF(2))(n), n = 1, 2 and C(60)(CCl(2)) has been investigated. [6,6]-Opened C(60)(CF(2)) and cis-2-C(60)(CF(2))(2) exhibit reversible reductions at potentials 150 and 145 mV more positive than C(60), unlike the related [6,6]-closed C(60)(CCl(2)), which shows reduction at the potential close to that for C(60). The structures, electron localization and lifetimes of the observed radical anions C(60)(CF(2))(-*) and cis-2-C(60)(CF(2))(2)(-*) have been elucidated by the ESR study and DFT calculations. The protonation pathway of decay of C(60)(CF(2))(-*) yields [6,6]-opened 1,9-dihydro-(1a,1a-difluoro-1aH-1(9)a-homo(C(60)-I(h))fullerene, C(60)(CF(2))H(2), which becomes the first characterized derivative of [6,6]-opened C(60)(CF(2)). DFT calculations of the structure and electron affinity of a number of homofullerene structures have been carried out to rationalize the experimental findings.