Too Persistent to Give Up: Aromaticity in Boron Clusters Survives Radical Structural Changes
dc.contributor.author
dc.date.accessioned
2020-06-11T08:29:08Z
dc.date.available
2022-10-28T05:46:33Z
dc.date.issued
2020-04-23
dc.identifier.issn
0002-7863
dc.identifier.uri
dc.description.abstract
o-C2B10H12 isomerizes to m-C2B10H12 upon heating at 400 ºC. Deboronation in o-C2B10H12 is a relatively easy process, whereas it is more difficult in m-C2B10H12. These two experimental facts indicate that m-C2B10H12 is thermodynamically more stable than o-C2B10H12. On the other hand, it is widely accepted that closo boranes and carboranes are aromatic compounds. In this work, we relate difficulty in the deboronation of the carboranes with stability and aromaticity. We do this by combining lab work and by means of DFT calculations. Computationally, our results show that the higher thermodynamic stability of m-C2B10H12 is not related to aromaticity differences but to the location of the C atoms in the carborane structure. It is also demonstrated that the aromaticity observed in closo boranes and carboranes is also present in their nido counterparts and, consequently, we conclude that aromaticity in boron clusters survives radical structural changes. Further, sandwich metallocenes (e.g. ferrocene) and sandwich metallabis(dicarbollides) (e.g. [Co(C2B9H11)2]-) have traditionally been considered similar. Here it is shown that they are not. Metallabis(dicarbollides) display global aromaticity whereas metallocenes present local aromaticity in the ligands. Remarkable and unique is the double probe given by 1H- and 11B-NMR tracing the reciprocally antipodal endocyclic open face Hec and B1. These magnetic studies have permitted to correlate both nuclei and relate them to a diatropic current in the plane at the middle of the nido [C2B9H12]-. This observation is the first and unique data that proves experimentally the existence of diatropic currents, thence aromaticity, in clusters and is comparable to the existence of diatropic currents in planar aromatic compounds. Additionally, heteroboranes with two carbon atoms have been compared to heterocycles with two nitrogen or boron atoms, C2B10H12 carboranes against planar N2C4H4 diazines or [B2C4H4]2- diboratabenzenes, proving the higher persistence of the aromaticity of the tri-dimensional compounds in heteroatom substituted species. This research accounts very well for the 'Paradigm for the Electron Requirements of Clusters' in which a closo-cluster that is aromatic upon addition of 2e- becomes also an aromatic nido species and explains the nice schemes by R.W. Rudolph and R. E. Williams
dc.description.sponsorship
This work has been supported by the Ministerio de Economía y Competitividad (MINECO) of Spain (Projects CTQ2017-85341-P, CTQ2016-75150-R, CTQ2016-77558-R, and MDM2017-0767) and the Generalitat de Catalunya (projects 2017SGR39, 2017SGR1720, and 2017SGR348)
dc.format.extent
12 p.
dc.format.mimetype
application/pdf
dc.language.iso
eng
dc.publisher
American Chemical Society (ACS)
dc.relation
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/CTQ2017-85341-P/ES/AVANCES EN LA REACTIVIDAD DE FULLERENOS Y NANOTUBOS: ESTUDIOS TEORICO-EXPERIMENTALES DE CICLACIONES CATALIZADAS POR METALES DE TRANSICION/
dc.relation.isformatof
Versió postprint del document publicat a: https://doi.org/10.1021/jacs.0c02228
dc.relation.ispartof
© Journal of the American Chemical Society, 2020, vol. 142, núm. 20, p. 9396-9407
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Articles publicats (D-Q)
dc.rights
Tots els drets reservats
dc.source
Poater i Teixidor, Jordi Viñas, Clara Bennour, Inés Escayola Gordils, Sílvia Solà i Puig, Miquel Teixidor Bombardó, Francesc 2020 Too Persistent to Give Up: Aromaticity in Boron Clusters Survives Radical Structural Changes Journal of the American Chemical Society 142 20 9396 9407
dc.subject
dc.title
Too Persistent to Give Up: Aromaticity in Boron Clusters Survives Radical Structural Changes
dc.type
info:eu-repo/semantics/article
dc.rights.accessRights
info:eu-repo/semantics/openAccess
dc.embargo.terms
2021-04-23T00:00:00Z
dc.date.embargoEndDate
info:eu-repo/date/embargoEnd/2021-04-23
dc.type.version
info:eu-repo/semantics/acceptedVersion
dc.identifier.doi
dc.identifier.idgrec
031603
dc.contributor.funder
dc.type.peerreviewed
peer-reviewed
dc.relation.FundingProgramme
dc.relation.ProjectAcronym
dc.identifier.eissn
1520-5126