%0 Journal Article
%J Catalysis Letters
%D 1992
%T Adsorption Effects in Aluminophosphate Molecular-Sieves Studied by Al-27 Double-Rotation Nmr
%A Jelinek, R.
%A Chmelka, B. F.
%A Wu, Y.
%A Davis, M. E.
%A Ulan, J. G.
%A Gronsky, R.
%A Pines, A.
%K alpo4-8
%X
Al-27 double rotation NMR (DOR) spectroscopy is used to investigate structural changes in the framework of several aluminophosphate molecular sieves upon adsorption of water. The shapes, widths, and positions of the spectral lines yield information on the aluminum environments, adsorption sites, and degree of structural disorder undergone upon water adsorption.
%B Catalysis Letters
%V 15
%P 65-73
%@ 1011-372X
%G English
%U ://WOS:A1992JJ25900008
%N 1-2
%M WOS:A1992JJ25900008
%! Adsorption Effects in Aluminophosphate Molecular-Sieves Studied by Al-27 Double-Rotation Nmr
%R Doi 10.1007/Bf00770899
%0 Journal Article
%J Solid State Nuclear Magnetic Resonance
%D 1992
%T Solid-state Al-27 NMR studies of aluminophosphate molecular sieves
%A Rocha, J.
%A Klinowski, J.
%A Barrie, P. J.
%A Jelinek, R.
%A Pines, A.
%K double-rotation
%X Solid-state Al-27 NMR spectra of several aluminophosphate molecular sieves have been recorded with conventional magic-angle spinning (MAS), double-rotation (DOR) and quadrupole nutation with fast MAS. Enhanced resolution was obtained in the quadrupole nutation experiment at certain radiofrequency pulse strengths. This extra resolution can be comparable to that attainable using DOR, and does not introduce spinning sidebands.
%B Solid State Nuclear Magnetic Resonance
%V 1
%P 217-225
%8 Nov
%@ 0926-2040
%G English
%U ://WOS:000208537300007
%N 4
%M WOS:000208537300007
%! Solid-state Al-27 NMR studies of aluminophosphate molecular sieves
%0 Journal Article
%J Nanotechnology
%D 1992
%T A study of nanostructure assemblies and guest-host interactions in sodium zeolite-Y using Na-23 double rotation NMR
%A Jelinek, R.
%A Pines, A.
%A Ozkar, S.
%A Ozin, G.A.
%B Nanotechnology
%P 182-186
%G eng
%N 2
%! A study of nanostructure assemblies and guest-host interactions in sodium zeolite-Y using Na-23 double rotation NMR
%0 Conference Paper
%D 1991
%T Framework ordering in aluminophosphate molecular sieves studied by (27)Al double rotation NMR
%A Chmelka, B.F.
%A Wu, Y.
%A Jelinek, R.
%A Davis, M.E.
%A Pines, A.
%E P.A. Jacobs, N.I. Jaeger, L. Kubelkova, and B. Wichterlov
%I Elsevier
%V 69
%P 435-442
%8 1991
%G eng
%0 Journal Article
%J Journal of the American Chemical Society
%D 1991
%T Study of the Aluminophosphates Alpo4-21 and Alpo4-25 by Al-27 Double-Rotation Nmr
%A Jelinek, R.
%A Chmelka, B. F.
%A Wu, Y.
%A Grandinetti, P. J.
%A Pines, A.
%A Barrie, P. J.
%A Klinowski, J.
%K nuclei
%X Aluminum-27 double-rotation NMR in a magnetic field of 11.7 T distinguishes the extremely distorted five-coordinated aluminum sites in the molecular sieve precursor ALPO4(-21). Upon calcination, ALPO4(-21) transforms to ALPO4(-25), which has two tetrahedral aluminum sites with similar isotropic chemical shifts that cannot be resolved in an 11.7 T field. The two tetrahedral environments, however, have a different quadrupole coupling constants and are distinguished by double rotation at 4.2 T field. The quadrupole coupling constants obtained for these sites indicates that the tetrahedral aluminum environments are less distorted in the hydrated material.
%B Journal of the American Chemical Society
%V 113
%P 4097-4101
%8 May 22
%@ 0002-7863
%G English
%U ://WOS:A1991FN00500007
%N 11
%M WOS:A1991FN00500007
%! Study of the Aluminophosphates Alpo4-21 and Alpo4-25 by Al-27 Double-Rotation Nmr
%R Doi 10.1021/Ja00011a007