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Analysis of a Compound Class with Triplet States Stabilized by Potentially Baird Aromatic [10] Annulenyl Dicationic Rings

The low-lying triplet state of a recently published compound (TMTQ) was analyzed quantum chemically in light of suggestions that it is influenced by Baird aromaticity. Two mesomeric structures describe this state: 1) a zwitterionic Baird aromatic structure with a triplet diradical 8π-electron methano[10]annulene (M10A) dicationic ring and 2) a Hückel aromatic with a neutral closed-shell 10π-electron ring. According to charge and spin density distributions, the Hückel aromatic structure dominates the triplet state (the Baird aromatic contributes at most 12 %), and separation of the aromatic fluctuation index (FLU) into α and β electron contributions emphasizes this finding. The small singlet-triplet energy gap is due to Hückel aromaticity of the M10A ring, clarified by comparison to the smaller analogues of TMTQ. Yet, TMTQ and its analogues are Hückel-Baird hybrids allowing for tuning between closed-shell 4n+2 Hückel aromaticity and open-shell 4n Baird aromaticity

This work has been supported by the Swedish Research Council (project grant 621-2011-4177), Ministerio de Economía y Competitividad (MINECO) of Spain (Project CTQ2014-54306-P) and the Generalitat de Catalunya (project 2014SGR931, Xarxa de ReferÀncia en Química Teòrica i Computacional, and ICREA Academia 2014 prize for M.S.). F.F. acknowledges financial support of the Beatriu de Pinûs programme from AGAUR for the postdoctoral grants BP_A_00339 and BP_A2_00022. M.S. and F.F. are grateful to the European Union (EU) for FEDER fund number UNGI10-4E-801

© Chemistry - A European Journal, 2016, vol. 22, núm. 8, p. 2793-2800

Wiley-VCH Verlag

Author: Jorner, Kjell
Feixas Geronès, Ferran
Ayub, Rabia
Lindh, Roland
Solà i Puig, Miquel
Ottosson, Henrik
Date: 2016
Abstract: The low-lying triplet state of a recently published compound (TMTQ) was analyzed quantum chemically in light of suggestions that it is influenced by Baird aromaticity. Two mesomeric structures describe this state: 1) a zwitterionic Baird aromatic structure with a triplet diradical 8π-electron methano[10]annulene (M10A) dicationic ring and 2) a Hückel aromatic with a neutral closed-shell 10π-electron ring. According to charge and spin density distributions, the Hückel aromatic structure dominates the triplet state (the Baird aromatic contributes at most 12 %), and separation of the aromatic fluctuation index (FLU) into α and β electron contributions emphasizes this finding. The small singlet-triplet energy gap is due to Hückel aromaticity of the M10A ring, clarified by comparison to the smaller analogues of TMTQ. Yet, TMTQ and its analogues are Hückel-Baird hybrids allowing for tuning between closed-shell 4n+2 Hückel aromaticity and open-shell 4n Baird aromaticity
This work has been supported by the Swedish Research Council (project grant 621-2011-4177), Ministerio de Economía y Competitividad (MINECO) of Spain (Project CTQ2014-54306-P) and the Generalitat de Catalunya (project 2014SGR931, Xarxa de ReferÀncia en Química Teòrica i Computacional, and ICREA Academia 2014 prize for M.S.). F.F. acknowledges financial support of the Beatriu de Pinûs programme from AGAUR for the postdoctoral grants BP_A_00339 and BP_A2_00022. M.S. and F.F. are grateful to the European Union (EU) for FEDER fund number UNGI10-4E-801
Format: application/pdf
ISSN: 0947-6539 (versió paper)
1521-3765 (versió electrònica)
Document access: http://hdl.handle.net/10256/12371
Language: eng
Publisher: Wiley-VCH Verlag
Collection: MINECO/PN 2015-2017/CTQ2014-54306-P
AGAUR/2014-2016/2014 SGR-931
Reproducció digital del document publicat a: http://dx.doi.org/10.1002/chem.201504924
Articles publicats (D-Q)
Is part of: © Chemistry - A European Journal, 2016, vol. 22, núm. 8, p. 2793-2800
Rights: Tots els drets reservats
Subject: Anulens
Annulenes
Aromaticitat (Química)
Aromaticity (Chemistry)
Compostos cíclics
Cyclic compounds
Title: Analysis of a Compound Class with Triplet States Stabilized by Potentially Baird Aromatic [10] Annulenyl Dicationic Rings
Type: info:eu-repo/semantics/article
Repository: DUGiDocs

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