Journal of Physical Chemistry B, Vol.109, No.1, 175-181, 2005
Solid-state NMR (F-19 and C-13) study of graphite monofluoride (CF)(n): 19F spin-lattice magnetic relaxation and F-19/C-13 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).