27 Al- 27 Al double-quantum single-quantum MAS NMR: Applications to the structural characterization of microporous materials.

In this paper, we review and illustrate applications, reported in the literature or used in our group, of 27 Al-27 Al double-quantum single-quantum (DQ-SQ) MAS NMR experiments for the structural characterization of Al-containing microporous solids, namely zeolites, aluminophosphates and metal-organic frameworks. Information regarding the periodic frameworks or the localization of the various aluminum species in the materials are obtained from the analysis of the two-dimensional NMR spectra, which allows getting local structural details sometimes inaccessible from other characterization technique. An application of 27 Al-27 Al of the DQ-SQ experiment for the detection of aluminum pairing in zeolite is shown.