Jv. Caspar et Y. Wang, EXCITED-STATE ELECTRON-TRANSFER OF FULLERENES - SINGLET-STATES VERSUSTRIPLET-STATES, Chemical physics letters, 218(3), 1994, pp. 221-228
We report that the quenching rate constants of the triplet states of f
ullerenes (C-70 and C-60) by aromatic amines such as N,N-diethylanilin
e and N-ethylcarbazole are at least four orders of magnitude smaller t
han those of the singlet states in methylcyclohexane. Such dramatic di
fferences between the singlet and triplet electron transfer rate const
ants from a single species, in spite of the states' apparently similar
energetics, are unprecedented. Several possible mechanisms are discus
sed. The data can be rationalized by the presence of structural distor
tion and biradical character in the triplet state.