Probing the structure of metal-substituted molecular sieves by solid-state NMR

摘要

Paramagnetic metal ions exert large influences on the NMR spectra of neighboring nuclei. The authors are using these effects to probe metal sites in zeolites and AlPO(sub 4) molecular sieves. In particular, they are studying (Co)-AlPO(sub 4)-5 because similar cobalt substituted AlPO(sub 4) sieves are reported in the literature. They have extended that work to probe the titanium zeolite TS-1 by comparing spectra of normal TS-1 to samples where the titanium has been reduced to the paramagnetic Ti(sup 3+). This promises to be a useful technique for determining framework substitution in many zeolite systems.