Monday, January 23, 2006

Chem. Mater.; 2005; 17(26) pp 6545 - 6554; (Article) DOI: 10.1021/cm050396j

Characterization of BAPO- and SAPO-Based Mesoporous Materials by Solid-State NMR Spectroscopy Yining Huang, Zhimin Yan, and Roger Richerpp 6545 - 6554; (Article) DOI: 10.1021/cm050396j

Comment: Phosphor NMR!!!!!!

Abstract: We have utilized several heteronuclear dipolar-coupling based 27Al/31P, 31P/11B, 27Al/11B, 27Al/29Si, and 1H/31P double-resonance solid-state NMR techniques to characterize boroaluminophosphate (BAPO)- and silicoaluminophosphate (SAPO)-based mesoporous materials. For the hexagonal BAPO materials, the coordination geometry of the B atoms in the framework is exclusively tetrahedral. The fraction of B atoms that can be incorporated in the framework seems not to depend on the B content of the initial gel. For the vast majority of the framework B atoms, the coordination environment is B(-OP)4. The B-O-Al linkages, however, also exist. The results indicate that the four-coordinated B atoms are not distributed randomly within the framework. Instead, they appear to be located on the channel surface. For the SAPO-based mesophase, the connectivities between various P and Al sites were mapped and the chemical environments of different P sites were determined to be as follows: (HO)2P[OAl(oct)]2, (HO)P[OAl(tet)]x[OAl(oct)]3-x, and (HO)P[OAl(tet)]3. The Si-O-Al linkages were detected unambiguously.

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