Title
Influence of the electron donor groups on the optical and electrochemical properties of borondifluoride complexes of curcuminoid derivatives: a joint theoretical and experimental study
Date Issued
2017
Access level
open access
Resource Type
journal article
Author(s)
Canard G.
Jacquemin D.
Le Guennic B.
Felouat A.
Rivoal M.
Zaborova E.
D'Aléo A.
Fages F.
Université de Rennes
Publisher(s)
Royal Society of Chemistry
Abstract
Molecules displaying a π-conjugated D-A-D structure, in which D and A are electron donor and acceptor groups, respectively, represent an important class of dyes. In this work, we present a series of borondifluoride complexes of curcuminoid derivatives in which the central dioxaborine ring acts as a strong electron acceptor unit. Compounds 1-15 differ by the nature of the terminal D groups. We have also studied unsymmetrical compounds 16-23 that contain two different terminal donor groups, as well as compounds 24-32 in which an electron acceptor or donor unit has been introduced at the meso position of the dioxaborine ring. We describe the synthesis of the dyes that have not yet been reported in the literature, and report the electrochemical, absorption and fluorescence properties of all the compounds in dichloromethane. To gain insights into the electronic structures and optical properties, we performed DFT/TD-DFT calculations for a panel of representative compounds. We established correlations between the reduction potential and the Hammett σ and σ+ constants, as well as between the redox gap and the emission wavelength. The electron donor character of one terminal D unit strongly influences (88 mV per unit of σ) the reduction potential due to the strong resonance interaction along the curcuminoid backbone. The correlation points to the smaller effect of the meso substituent (50 mV per unit of σ), which we relate to the twisted ground-state geometry of the meso aryl substituent. The correlation models established in this study may be useful to anticipate the optical and electrochemical properties of borondifluoride complexes of curcuminoids with good reliability.
Start page
10132
End page
10142
Volume
7
Issue
17
Language
English
OCDE Knowledge area
Electroquímica
Scopus EID
2-s2.0-85012024609
Source
RSC Advances
ISSN of the container
20462069
Sponsor(s)
Part of this work was supported by the French National Research Agency (Chalcones ANR-14-CE05-0035-01). D. J. is indebted to the European Research Council (ERC) for support in the framework of the Marches-278845 grant. This work used computational resources of the GENCI/IDRIS-CINES and of the CCIPL.
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