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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, Angew. Chem. Int. Ed. 2015, 20, 5888), was analyzed quantum chemically in light of suggestions that it is influenced by Baird-aromaticity. Two mesomeric structures describe this state; a zwitterionic Baird-aromatic structure with a triplet biradical 8pi-electron methano[10]annulene (M10A) dicationic ring, and a Hückel-aromatic with a neutral closed-shell 10pi-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 FLU aromaticity index into alpha and beta 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 Referència en Química Teòrica i Computacional, and ICREA Academia 2014 prize for M.S.). F.F. acknowledges financial support of the Beatriu de Pinós 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

Wiley-VCH Verlag

Manager: Ministerio de Economía y Competitividad (Espanya)
Generalitat de Catalunya. Agència de Gestió d’Ajuts Universitaris i de Recerca
Author: Jorner, Kjell
Feixas Geronès, Ferran
Ayub, Rabia
Lindh, Roland
Solà i Puig, Miquel
Ottosson, Henrik
Abstract: The low-lying triplet state of a recently published compound (TMTQ, Angew. Chem. Int. Ed. 2015, 20, 5888), was analyzed quantum chemically in light of suggestions that it is influenced by Baird-aromaticity. Two mesomeric structures describe this state; a zwitterionic Baird-aromatic structure with a triplet biradical 8pi-electron methano[10]annulene (M10A) dicationic ring, and a Hückel-aromatic with a neutral closed-shell 10pi-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 FLU aromaticity index into alpha and beta 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 Referència en Química Teòrica i Computacional, and ICREA Academia 2014 prize for M.S.). F.F. acknowledges financial support of the Beatriu de Pinós 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
Document access: http://hdl.handle.net/2072/297510
Language: eng
Publisher: Wiley-VCH Verlag
Rights: Tots els drets reservats
Subject: Aromaticitat (Química)
Aromaticity (Chemistry)
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: Recercat

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