HIGH-RESOLUTION AL-27 NMR-SPECTROSCOPY OF THE ALUMINOPHOSPHATE MOLECULAR-SIEVE VPI-5

ALUMINIUM plays an important part in determining the properties of many materials, such as the catalytic behaviour of zeolites. Aluminophosphate molecular sieves, in particular, have useful applications as superlattice hosts in the fabrication of quantum-effect devices1. Although nuclear magnetic resonance (NMR) spectroscopy is often a sensitive probe of solids, the use of 27Al NMR to investigate the structure of aluminosilicates and alumino-phosphates has been severely limited because anisotropic second-order quadrupolar interactions, responsible for spectral broadening, cannot be eliminated by conventional magic-angle-spinning or multiple-pulse techniques. Here we report the first high-resolution NMR spectra of 27A1 in a solid using double rotation2-4 and demonstrate its usefulness for probing subtle structural perturbations in the aluminophosphate molecular sieve VPI-55,6. From our results, we conclude that high-resolution 27A1 NMR is capable of resolving discrete framework aluminium sites, permitting quantitative investigation of site-specific adsorbate interactions with the VPI-5 host. © 1990 Nature Publishing Group.