Croatica Chemica Acta, Vol. 90 No. 4, 2017.
Original scientific paper
https://doi.org/10.5562/cca3241
Effect of Methoxy Substitution on Supramolecular Arrangement of Borondifluorides of 2'-Hydroxy Chalcones and their Solid-State NIR Fluorescence
Anthony D'Aléo
; Aix Marseille Univ, CNRS, CINaM UMR 7325, Campus de Luminy, Case 913, 13288 Marseille, France
Elena Zaborova
; Aix Marseille Univ, CNRS, CINaM UMR 7325, Campus de Luminy, Case 913, 13288 Marseille, France
Frédéric Fages
orcid.org/0000-0003-2013-0710
; Aix Marseille Univ, CNRS, CINaM UMR 7325, Campus de Luminy, Case 913, 13288 Marseille, France
Abstract
This work describes the borondifluoride complexes of 2'-hydroxychalcone derivatives, 2 and 3, differently substituted with methoxy groups. Their optical study in dichloromethane reveals similar UV-vis absorption and fluorescence emission features in the visible spectral region that are close to those of the parent compound 1. While fluorescence quantum yields Φf are very low in solution, they are higher in the solid state, showing that aggregation-induced enhanced emission occurs. Remarkably, the solid-state emission spectra are strongly red-shifted reaching the near infrared (NIR) spectral range. Molecular structures of 2 and 3 were determined by single crystal X-ray diffraction. The data show the occurrence of tightly packed arrangements that favor strong π-π overlap between neighboring molecules. Such situation allows the generation of promising NIR emitting materials, such as compound 3 emitting at 784 nm with Φf = 0.07 that stands as one of the best NIR solid-state organic emitters.
This work is licensed under a Creative Commons Attribution 4.0 International License.
Keywords
fluorescence; solid state; near infrared; boron complexes; chalcones
Hrčak ID:
193868
URI
Publication date:
29.12.2017.
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