Towards measurement of homonuclear dipolar couplings in H-1 solid-state NMR: recoupling with a rotor-synchronized decoupling scheme
Résumé
We describe a magic-angle spinning NMR experiment for H-1-H-1 homonuclear dipole-dipole coupling estimations in organic solids. The methodology involves reintroducing dipolar interactions with rotor-synchronized homonuclear decoupling pulse sequences. Frequency-selective DANTE pulses are used to isolate a specific spin pair from a natural isotopic abundance sample. The coupling of interest, between the selected spin pair, may be extracted by a non linear least-squares fit of the experimentally observed modulation of the signal intensity to an exact analytical formula. The experiment is demonstrated on natural isotopic abundance glycine and alanine powder samples.