F-19 NMR and EPR study of fluorinated buckminsterfullerene C60F58

Solid state F-19 NMR in the temperature range from 96 to 366 K and room temperature EPR studies of fluorinated buckminsterfullerene C60F58 have been carried out. The temperature dependence of the line width and the spin-lattice relaxation time show hindered molecular motion with the activation energy of DeltaE(a) = 1.9 kcal/mol. Neither phase transition nor random rotation of C60F58 have been obtained. The spin-lattice relaxation rate is strongly affected by the presence of paramagnetic centers, namely, dangling C-C bonds yielding localized Impaired electrons. Such broken bonds are caused by C-C bond rupture in a cage-opened structure of hyperfluorinated species. (C) 2002 Elsevier Science Ltd. All rights reserved.