Solid state NMR studies of covalent graphite fluorides (CF)n and (C2F)n

Various covalent graphite fluorides were studied using solid state nuclear magnetic resonance (NMR). F-19 magic angle spinning (MAS) NMR, C-13 MAS NMR and C-13 MAS NMR with F-19 to C-13 Cross Polarization (CP) allow both the presence of CF and CF2 groups and the carbon atoms hybridization, sp(2) or sp(3), to be determined. F-19 spin-lattice relaxation time T-1 of the F-19 line is presented. The effects of paramagnetic centers on the relaxation were evaluated. Paramagnetic oxygen is shown to be an important source of relaxation. The presence of a molecular motion with an activation energy of 1.685 kJ mol(-1) is also evidenced for one of the (CF)(n) sample. (c) 2006 Elsevier Ltd. All rights reserved.