(C-13, H-2) RESIDUAL DIPOLAR AND INDIRECT SPIN-SPIN COUPLING EFFECTS IN HIGH-RESOLUTION C-13 NUCLEAR-MAGNETIC-RESONANCE SPECTRA OF SOLIDS

We report high-resolution solid-state C-13 NMR spectra of urea and thiourea inclusion compounds containing deuteriated guest molecules. The spectra (recorded under conditions of magic-angle sample spinning and high-power H-1 decoupling at several magnetic fields from 4.7 to 11.7 T) for CD, CD2 and CD3 groups are triplets, pentets and heptets, respectively These multiplets arise from the effects of residual dipolar interaction and indirect spin-spin coupling between C-13 and H-2. A full analysis of these lineshapes is presented, and the effect of molecular motion is discussed. It is shown that the C-13 NMR lineshape for deuteriated materials which are in a rapid motion regime (with respect to the H-2 NMR timescale) can be rationalized by considering the motionally averaged H-2 quadrupole coupling constant [chi].