A F-19/SI-29 CP MAS NMR-STUDY OF MICROPOROUS SOLIDS SYNTHESIZED IN FLUORIDE MEDIUM

A new cross-polarization (CP) technique using fluorine as a magnetization source for silicon was applied to zeolitic materials synthesized in fluoride medium. Sodium hexafluorosilicate was used for Hartmann-Hahn matching and the reliability of the CP technique was tested with a fluoride clathrasil whose structure is well known. H-1/Si-29 and F-19/Si-29 CP MAS spectra of as-synthesized fluoride silicalite were compared. F-19/Si-29 CP MAS n.m.r. proved to be a useful tool to improve the sensitivity of the silicon nucleus and also a discriminating technique to specify the location of the fluorine in the zeolitic framework.