TY - CHAP
T1 - Off-nucleus magnetic shielding
T2 - Theory and applications
AU - Karadakov, Peter B.
N1 - © 2022 Elsevier Ltd
PY - 2022
Y1 - 2022
N2 - It is shown that computed off-nucleus isotropic magnetic shielding isosurfaces and contour plots provide a feature-rich picture of aromaticity and chemical bonding in ground and excited molecular electronic states, which is both quantitative and easy-to-visualise and interpret. These isosurfaces and contour plots make good chemical sense as at atomic positions they are pinned to the nuclear shieldings which, for electronic ground states, are experimentally measurable through chemical shifts. The examples discussed include ground and excited-state aromaticity and antiaromaticity in benzene, cyclobutadiene, cyclooctatetraene and Möbius conjugated rings, the contest between aromaticity and antiaromaticity in norcorrole, the smallest cyclic tetrapyrrole porphyrin analogue synthesized so far, and modern shielding-based visual interpretations of Clar's aromatic sextet theory, heteroaromaticity and multiple carbon-carbon bonds.
AB - It is shown that computed off-nucleus isotropic magnetic shielding isosurfaces and contour plots provide a feature-rich picture of aromaticity and chemical bonding in ground and excited molecular electronic states, which is both quantitative and easy-to-visualise and interpret. These isosurfaces and contour plots make good chemical sense as at atomic positions they are pinned to the nuclear shieldings which, for electronic ground states, are experimentally measurable through chemical shifts. The examples discussed include ground and excited-state aromaticity and antiaromaticity in benzene, cyclobutadiene, cyclooctatetraene and Möbius conjugated rings, the contest between aromaticity and antiaromaticity in norcorrole, the smallest cyclic tetrapyrrole porphyrin analogue synthesized so far, and modern shielding-based visual interpretations of Clar's aromatic sextet theory, heteroaromaticity and multiple carbon-carbon bonds.
KW - Antiaromaticity
KW - Aromaticity
KW - Excited state aromaticity reversals
KW - NICS
KW - Off-nucleus shielding
UR - http://www.scopus.com/inward/record.url?scp=85136220087&partnerID=8YFLogxK
U2 - 10.1016/bs.arnmr.2022.07.001
DO - 10.1016/bs.arnmr.2022.07.001
M3 - Chapter
AN - SCOPUS:85136220087
VL - 107
T3 - in Annual Reports on NMR Spectroscopy
SP - 95
EP - 131
BT - Annual Reports on NMR Spectroscopy
A2 - Webb, Graham
PB - Elsevier
ER -