Perfluorobicyclopentenyl (1a) and -butenyl (2a) react with decamethylf
errocene (3), to give charge-transfer salts 4 and 5, respectively; per
fluorohexakis (trifluoromethyl) cyclo-pentadiene (6) forms a salt (8)
containing the C-5(CF3)(5) anion, Crystal structures of the salts 4 an
d 5 have been determined; both contain centrosymmetric trans-diene rad
ical anions.