Solid-state NMR (19F and 13C) study of graphite monofluoride (CF)n:: 19F spin-lattice magnetic relaxation and 19F/13C distance determination by Hartmann-Hahn cross polarization

Graphite monofluoride (CF)(n) was studied by solid-state NMR. F-19 spin-lattice relaxation time T-1 and second moment measurements of the F-19 line are presented. A chair conformation structure is found to be compatible with the experimental data. Relaxation is shown to be mainly due to paramagnetic oxygen. The presence of a molecular motion with an activation energy of 1.685 kJ(.)mol(-1) (202.7 K) is also evidenced. F-19 magic angle spinning (MAS) NMR and C-13 MAS NMR with F-19 to C-13 cross-polarization allows the determination of CF and CF2 groups. Reintroduction of dipolar coupling by cross-polarization is used for C-F bond length determination (0.138 +/- 0.001 nm).