Structure and NMR assignment in calcined and as-synthesized forms of AlPO-14 : a combined study by first-principles calculations and high- resolution Al-27-P-31 MAS NMR correlation
Ashbrook, Sharon E., Cutajar, Marica, Pickard, Chris J., Walton, Richard I. and Wimperis, Stephen. (2008) Structure and NMR assignment in calcined and as-synthesized forms of AlPO-14 : a combined study by first-principles calculations and high- resolution Al-27-P-31 MAS NMR correlation. Physical Chemistry Chemical Physics, Vol.10 (No.37). pp. 5754-5764. ISSN 1463-9076Full text not available from this repository.
Official URL: http://dx.doi.org/10.1039/b805681a
The high-resolution Al-27 and P-31 NMR spectra of two as-synthesized forms of the microporous aluminophosphate AlPO-14 and the corresponding calcined -dehydrated form were assigned using both "first-principles'' calculations of NMR parameters (GIPAW, as implemented in NMR-CASTEP) and a Al-27-P-31 heteronuclear correlation NMR experiment (MQ-J-HETCOR) that exploits Al-27 multiple-quantum coherences and J couplings to identify Al-O-P linkages. NMR parameters calculated from published AlPO-14 crystal structures, which are derived from powder X-ray diffraction (XRD) data, are in poor agreement with experiment and it was necessary to optimize the structure geometry using energy minimization before satisfactory agreement was obtained. Comparison of simulated powder XRD patterns from the experimental and the energy-minimized structures shows that the changes in relative atomic positions in the optimized structure are relatively small and yield only minor adjustments in the Bragg peak intensities. These results indicate that a combination of NMR spectroscopy and first-principles calculation of NMR parameters may soon be considered a generally useful step in the refinement of the structures of microporous materials derived from powder diffraction data.
|Item Type:||Journal Article|
|Subjects:||Q Science > QD Chemistry
Q Science > QC Physics
|Divisions:||Faculty of Science > Chemistry|
|Library of Congress Subject Headings (LCSH):||Phosphates, Porous materials -- Structure, Nuclear magnetic resonance, X-rays -- Diffraction, Nuclear magnetic resonance spectroscopy|
|Journal or Publication Title:||Physical Chemistry Chemical Physics|
|Publisher:||Royal Society of Chemistry|
|Number of Pages:||11|
|Page Range:||pp. 5754-5764|
|Funder:||Royal Society (Great Britain), Research Councils UK (RCUK), Engineering and Physical Sciences Research Council (EPSRC)|
|Grant number:||GR/S96579 (EPSRC)|
1 S. T. Wilson, B. M. Lok, C. A. Messina, T. R. Cannan and E. M.
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