Brown, S.P., Ashbrook, S.E., and Wimperis, S. (1999) 27Al multiple-quantum magic angle spinning NMR study of the thermal transformation between the microporous aluminum methylphosphonates AlMePO-β and AlMePO-α. Journal of Physical Chemistry B, 103 (5). pp. 812-817. ISSN 1520-6106 (doi:10.1021/jp9824858)
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The 27Al multiple-quantum magic angle spinning (MQMAS) NMR technique is used to investigate the thermal transformation between AlMePO-β and AlMePO-α. The required spectral resolution is achieved using a novel split-t1 version of the basic five-quantum MAS experiment. The five-quantum split-t1 27Al MAS NMR spectrum of a sample where the thermal transformation has been interrupted before complete conversion is compared with that of a simple physical mixture of the α- and β-polymorphs. The two spectra are shown to be different, a result that does not appear to support the proposition by Carter et al. (J. Mater. Chem. 1997, 7, 2287) of a topotactic reconstructive transformation. On the basis of our 27Al MQMAS results, we outline a possible alternative (and rather more commonplace) mechanism for the thermal transformation.
|Glasgow Author(s):||Wimperis, Prof Stephen|
|Authors:||Brown, S.P., Ashbrook, S.E., and Wimperis, S.|
|Subjects:||Q Science > QD Chemistry|
|College/School:||College of Science and Engineering > School of Chemistry|
|Journal Name:||Journal of Physical Chemistry B|
|Published Online:||15 January 1999|