Rotary resonance recoupling of 13C-1H dipolar interactions in magic angle spinning 13C NMR of dynamic solids

Rotary resonance recoupling of heteronuclear C-13 - H-1 dipolar interactions in magic angle spinning solid state C-13 NMR spectra (recorded under conditions of H-1 decoupling at frequency nu(1) and magic angle spinning at frequency nu(r)) has been studied for three examples of molecular solids (adamantane, ferrocene and hexamethylbenzene) in which substantial molecular motion is known to occur. It is shown that when rotary resonance conditions are satisfied (i.e. nu(1)/nu(r) = n, for n = 1 or 2), the recoupling can lead to motionally averaged Fake-like powder patterns from which information on C-13 - H-1 internuclear distances and/or molecular motion can be derived. (C) 2000 Elsevier Science B.V. All rights reserved.