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Elucidating natural product structures using a robust measurement of carbon residual chemical shift anisotropy combined with DFT
Author(s) -
Das Akhi,
Nath Nilamoni
Publication year - 2021
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.4975
Subject(s) - chemistry , anisotropy , isotropy , residual dipolar coupling , chemical shift , density functional theory , residual , molecule , nuclear magnetic resonance , chemical physics , dipole , computational chemistry , molecular physics , organic chemistry , physics , algorithm , quantum mechanics , computer science
Determination of configurations and conformations is an important step in the structural characterization of small molecules. Apart from utilizing isotropic J ‐couplings and nuclear overhauser effect (NOEs) measured in isotropic solution, anisotropic Nuclear Magnetic resonance (NMR) data such as residual dipolar couplings and residual chemical shift anisotropies (RCSAs) were also used to elucidate complex small molecule structures. Measuring RCSA has always been historically difficult due to the isotropic shift effect accompanied by molecular alignment and therefore only occasionally applied in a few examples. Here, we present a robust measurement of carbon RCSAs using a smaller gel‐stretching device to determine the structures of a few small molecules. A systematic study on how different density functional theory computed anisotropies of the chemical shift anisotropy tensors impact RCSA data interpretation has also been discussed. We also discuss the effect of utilizing various carbons as reference nuclei for RCSA data extraction as well as the orientation behavior of estrone in orthogonal alignment media.