Biaxial Q-shearing of 27Al 3QMAS NMR spectra: insight into the structural disorder of framework aluminosilicates

0425217 - ÚMCH 2014 RIV GB eng J - Journal Article
Kobera, Libor - Brus, Jiří - Klein, Petr - Dědeček, Jiří - Urbanová, Martina
Biaxial Q-shearing of 27Al 3QMAS NMR spectra: insight into the structural disorder of framework aluminosilicates.
Solid State Nuclear Magnetic Resonance. 57-58, February–April (2014), s. 29-38. ISSN 0926-2040. E-ISSN 1527-3326
R&D Projects: GA ČR(CZ) GA13-24155S; GA AV ČR IAA400400904
Institutional support: RVO:61389013 ; RVO:61388955
Keywords : 27Al 3QMAS NMR * biaxial shearing * zeolites
Subject RIV: JN - Civil Engineering; CF - Physical ; Theoretical Chemistry (UFCH-W)
Impact factor: 2.266, year: 2014

In this contribution, we present the application potentiality of biaxial Q-shearing of 27Al 3QMAS NMR spectra in the analysis of structural defects of aluminium units in aluminosilicates. This study demonstrates that the combination of various shearing transformations of the recorded 27Al 3QMAS NMR spectra enables an understanding of the broadening processes of the correlation signals of disordered framework aluminosilicates, for which a wide distribution of 27Al MAS NMR chemical shifts and quadrupolar parameters (i.e., second-order quadrupolar splitting and quadrupole-induced chemical shifts) can be expected. By combining the suitably selected shearing transformation procedures, the mechanisms of the formation of local defects in aluminosilicate frameworks, including Al/Si substitution effects in the next-nearest neighbouring T-sites, variations in bond angles, and/or variations in the physicochemical nature of charge-balancing counter-ions, can be identified. The proposed procedure has been extensively tested on a range of model aluminosilicate materials (kyanite, γ-alumina, metakaolin, analcime, chabazite, natrolite, phillipsite, mordenite, zeolite A, and zeolite Y).
Permanent Link: http://hdl.handle.net/11104/0231692