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

The multiple-quantum magic angle spinning (MQMAS) NMR method can be extende d to allow for investigation of the interatomic connectivities between quad rupolar 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 inte ractions between quadrupolar and spin-1/2 nuclei under high-resolution cond itions. The theoretical and experimental aspects of the spin dynamics invol ved in these new methods will be discussed. Examples of experimental result s 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.