Anstöter, C.S., Gibson, C.M. and Fowler, P.W. orcid.org/0000-0003-2106-1104 (2020) Modelling aromatisation of (BN)nH2n azabora-annulenes. Physical Chemistry Chemical Physics, 22 (28). pp. 15919-15925. ISSN 1463-9076
Abstract
Despite a long tradition of descriptions of borazine as an ‘inorganic benzene’, this molecule is a non-aromatic species according to the magnetic (ring-current) criterion. Borazine, borazocine, and the larger neutral (BN)nH2n azabora-annulene heterocycles in planar conformations, although π-isoelectronic with [2n]annulenes, support only localized induced currents in perpendicular magnetic fields. The π-current maps of these systems comprise superpositions of separate ‘lone-pair’ circulations on all nitrogen centres. For the systems with n > 4, planarity must be enforced by a constraint. Qualitative orbital analysis based on the ipsocentric approach to calculation of induced current density suggests that global induced currents could be produced through strategic changes to the π electron count. In ab initio calculations, azabora-annulenes with rings of size [8]- and larger were indeed found to support global diatropic ring currents in both anionic and cationic forms with (4N + 2) π electron counts. The planar conformation of the charged ring typically occupies a stationary point of higher order on the potential energy surface, rather than a minimum. However, the borazocine dianion, [B4N4H8]2−, occupies a planar minimum, supports a diatropic ring current of strength comparable to that in benzene, and is predicted to participate in sandwich compounds; it is therefore a good candidate for an aromatised azabora-annulene.
Metadata
Item Type: | Article |
---|---|
Authors/Creators: |
|
Copyright, Publisher and Additional Information: | © 2020 The Royal Society of Chemistry. This is an author-produced version of a paper subsequently published in Physical Chemistry Chemical Physics. Uploaded in accordance with the publisher's self-archiving policy. |
Dates: |
|
Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Chemistry (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 30 Oct 2020 12:32 |
Last Modified: | 07 Jul 2021 00:38 |
Status: | Published |
Publisher: | Royal Society of Chemistry (RSC) |
Refereed: | Yes |
Identification Number: | 10.1039/d0cp02284e |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:167438 |