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Solid‐State NMR Spectroscopic and X‐Ray Diffraction Studies of the Low‐Temperature Structural Transformation of Hydrated Porous Aluminophosphate VPI‐5
Author(s) -
Rocha João,
Kolodziejski Waclaw,
Gameson Ian,
Klinowski Jacek
Publication year - 1992
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.199206101
Subject(s) - magic angle spinning , nutation , materials science , solid state nuclear magnetic resonance , crystallography , spinning , magic angle , diffraction , nuclear magnetic resonance spectroscopy , molecule , nmr spectra database , chemistry , nuclear magnetic resonance , spectral line , polymer chemistry , stereochemistry , organic chemistry , optics , physics , astronomy
Only from NMR spectra can the reversible structural transformation at low temperatures in the hydrated aluminophosphate molecular sieve VPI‐5 be detected. Although powder diffraction experiments reveal a continuous shortening of the c axis of the unit cell, magic‐angle‐spinning solid‐state NMR spectroscopy shows completely reversible changes between 190 K and 220 K, which are possibly attributable to the freezing of the motion of encapsulated water molecules. In these studies, variable temperature 27 Al quadrupole nutation NMR with magic‐angle‐spinning was used for the first time.