Measurement of interatomic connectivities in molecular sieves using MQMAS-based methods

The multiple-quantum magic angle spinning (MQMAS) NMR method can be extended to allow for investigation of the interatomic connectivities between quadrupolar and spin-1/2 nuclei. Several new experiments will be reviewed that combine MQMAS with cross polarization (CP) or heteronuclear recoupling via rotational echo double resonance (REDOR) in order to probe the dipolar interactions between quadrupolar and spin-1/2 nuclei under high-resolution conditions. The theoretical and experimental aspects of the spin dynamics involved in these new methods will be discussed. Examples of experimental results will be presented, involving the H-1-Al-27, and F-19-Al-27 spin pairs in fluorinated and hydrated aluminophosphates. (C) 1999 Elsevier Science B.V. All rights reserved.