Off-nucleus magnetic shielding: Theory and applications

Research output: Chapter in Book/Report/Conference proceedingChapter

Abstract

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.

Original languageEnglish
Title of host publicationAnnual Reports on NMR Spectroscopy
EditorsGraham Webb
PublisherElsevier
Number of pages39
Volume103
DOIs
Publication statusAccepted/In press - 2022

Publication series

Namein Annual Reports on NMR Spectroscopy
PublisherElsevier
Volume103
ISSN (Print)0066-4103

Bibliographical note

© 2022 Elsevier Ltd

Keywords

  • Antiaromaticity
  • Aromaticity
  • Excited state aromaticity reversals
  • NICS
  • Off-nucleus shielding

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