From 2-phenylbenzoxazole to diphenyl-bibenzoxazole derivatives: Comparative advantages of mono- and bis-chromophores for solution and solid-state fluorescence. (February 2016)

• Record Type: Journal Article
• Authors: Ghodbane, Abdelhamid; Bordat, Patrice; Saffon, Nathalie; Blanc, Sylvie; Fery-Forgues, Suzanne
• Is Part Of: Dyes and pigments. Volume 125(2016)
• Page Start: 282
• Page End: 291
• Publication Date: 2016-02
• Subjects: Crystal structure determination -- Fluorescent probes -- Photoluminescence -- Optical properties -- DFT calculations -- Non-doped emitter; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2015.10.027
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: The optical properties of three bis-benzoxazole derivatives, namely 2, 2'-diphenyl-6, 6'-bibenzoxazole and its derivatives bearing methyl and tert -butyl groups at the para position, were investigated and compared to those of the corresponding subunits. As expected from the increase of the π-electron conjugated system, the absorption and fluorescence spectra were red-shifted when passing from mono-to bis-chromophores. The three bis-benzoxazoles showed superior fluorescence quantum yields in solution, but they were only weakly emissive in the solid state, the unsubstituted derivative even being virtually not photoluminescent. The solid-state behaviour was explained by the fact that bis-chromophoric molecules were locked in a non-planar conformation, as discussed on the basis of DFT calculations and X-ray data. Highlights: 2-Phenylbenzoxazoles were well fluorescent in solution and in the solid state. Bis-benzoxazoles had superior emission in solution. In the solid state, their twisted conformation was a disadvantage for photoluminescence. Graphical abstract: