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Measurement of residual chemical shift anisotropies in compressed polymethylmethacrylate gels. Automatic compensation of gel isotropic shift contribution
Author(s) -
Hallwass Fernando,
Teles Rubens R.,
Hellemann Erich,
Griesinger Christian,
Gil Roberto R.,
NavarroVázquez Armando
Publication year - 2018
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.4711
Subject(s) - residual , anisotropy , isotropy , chemistry , polymer , compression (physics) , residual dipolar coupling , tensor (intrinsic definition) , a priori and a posteriori , dipole , composite material , optics , materials science , algorithm , organic chemistry , geometry , physics , philosophy , mathematics , epistemology , computer science
Mechanical compression of polymer gels provides a simple way for the measurement of residual chemical shift anisotropies, which then can be employed, on its own, or in combination with residual dipolar couplings, for structural elucidation purposes. Residual chemical shift anisotropies measured using compression devices needed a posteriori correction to account for the increase of the polymer to solvent ratio inside the swollen gel. This correction has been cast before in terms of a single‐free parameter which, as shown here, can be simultaneously optimized along with the components of the alignment tensor while still retaining discriminating power of the different relative configurations as illustrated in the stereochemical analysis of α‐santonin and 10‐epi‐8‐deoxycumambrin B.