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Tuning J‐aggregate Formation and Emission Efficiency in Cationic Diazapentacenium Dyes

Rodrigues, Ana Clara B. ; Wetterling, Dario ; Scherf, Ullrich ; Seixas de Melo, J. Sérgio

Chemistry : a European journal, 2021-05, Vol.27 (29), p.7826-7830 [Periódico revisado por pares]

Germany: Wiley Subscription Services, Inc

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  • Título:
    Tuning J‐aggregate Formation and Emission Efficiency in Cationic Diazapentacenium Dyes
  • Autor: Rodrigues, Ana Clara B. ; Wetterling, Dario ; Scherf, Ullrich ; Seixas de Melo, J. Sérgio
  • Assuntos: Acetonitrile ; Aggregates ; AIE ; Chemistry ; Communication ; Communications ; Coupling (molecular) ; Cross coupling ; diazapentacene ; Dichloromethane ; fluorescence ; J-aggregates ; Nitrogen atoms ; Optical properties ; photochemistry ; Photoluminescence ; Photons ; Salts ; Solvents ; Thin films
  • É parte de: Chemistry : a European journal, 2021-05, Vol.27 (29), p.7826-7830
  • Notas: ObjectType-Article-1
    SourceType-Scholarly Journals-1
    ObjectType-Feature-2
    content type line 23
  • Descrição: Enhancement of the luminescence efficiency of two new diazapentacenium salts (D1 and D2) of more than 55 for D1 and 22 times for D2) in poor solvents, acetonitrile and/or dichloromethane, was observed and rationalized as formation of emissive J‐aggregates. Both compounds displaying 4‐n‐decylphenyl substituents at the 7,14‐carbons and phenyl (D1) or 2,6‐difluorophenyl (D2) substituents at the quaternary nitrogen atoms in 5,12‐positions have been synthetized in a two‐step procedure involving a two‐fold Buchwald‐Hartwig‐type CN cross‐coupling and an electrophilic Friedel‐Crafts‐type cyclization. The optical properties of the dicationic diazapentacenium salts in various solvents and in thin films have been investigated by steady‐state and time‐resolved absorption and photoluminescence spectroscopies. In thin films and in good solvents, isolated molecules coexist with aggregates. Nonetheless, D1 is seven times more emissive than D2, reflecting a higher J‐aggregate contribution in the former. Two new diazapentacenium salts have been obtained from a new synthetic methodology and shown to display a drastic increase of fluorescence quantum yields induced by aggregation (AIE phenomena) in poor solvents and associated to a particular type of aggregates organization: J‐aggregates. A simple structural modification (4 H in D1 vs 4 F in D2) changes the contribution of J‐aggregates which is quantitatively followed by time resolved fluorescence.
  • Editor: Germany: Wiley Subscription Services, Inc
  • Idioma: Inglês
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  • Realização: ABCD-USP USP   Logos de Redes Sociais: Freepik

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