Wolf, P., et al., NMR Signatures of the Active Sites in Sn-β Zeolite. Angewandte Chemie, 2014. 126(38): p. 10343-1031. Wolf, P., et al., NMR Signatures of the Active Sites in Sn-β Zeolite. Angewandte Chemie, 2014. 126(38): p. 10343-10347.47.
http://dx.doi.org/10.1002/ange.201403905
Dynamic nuclear polarization surface enhanced NMR (DNP-SENS), Mössbauer spectroscopy, and computational chemistry were combined to obtain structural information on the active-site speciation in Sn-β zeolite. This approach unambiguously shows the presence of framework SnIV-active sites in an octahedral environment, which probably correspond to so-called open and closed sites, respectively (namely, tin bound to three or four siloxy groups of the zeolite framework).