Rational design of slightly twisted coumarin molecules with remarkable solution and solid dual efficient luminescence. (February 2018)

• Record Type: Journal Article
• Authors: Sun, Yue; Wu, Tong; Zhang, Fang; Zhang, Rong; Wu, Min; Wu, Yuezhen; Liang, Xiaozhong; Guo, Kunpeng; Li, Jie
• Is Part Of: Dyes and pigments. Volume 149(2018)
• Page Start: 73
• Page End: 81
• Publication Date: 2018-02
• Subjects: Coumarin derivatives -- Slightly twisted conformation -- Intramolecular charge transfer -- Molecular packing pattern -- Dual efficient luminescence; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2017.09.060
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: Endowing slightly twisted molecules highly emissive in both solution and solid state is of great importance for understanding the principle of maximizing the luminescent efficiency of luminophores. To this end, a series of slightly twisted coumarin luminophoresCM s with different alkoxyl substituents at the 7-positions were synthesized. The effect of the substitutes on the diversity photophysical properties of the four compounds in solution, THF/H2 O mixtures and solid state were investigated. Comparing to the referenced compoundCM (3- p -tolyl-2H-chromen-2-one) that without a substitute, the introduced electron-rich alkoxyl substitutes not only enhanced the intramolecular charge transfer (ICT) effect, but also significantly modified their molecular packing patterns in the crystals. The combined effect of increasing the radiative and suppressing the nonradiactive pathways boosted the luminescence efficiency ofCM1 -CM3 in solution and the solid state simultaneously. Eventually, compoundCM2 with an ethoxyl substitute exhibited the strongest blue emission with fluorescence quantum yields as high as 73.2% and 96.7% in solution and the solid state, respectively. This work presents an efficient strategy towards dual strong fluorescent luminophores in both solution and the solid state. Graphical abstract: Dual efficient slightly twisted coumarin derivatives in solution and solid were realized by modulating intramoleculat charge transfer (ICT) and molecular pattern in crystal. Highlights: Four slightly twisted coumarin luminophores with different alkoxyl substituents at the 7-positions were synthesized. The introduced alkoxyl substitutes enhanced the ICT effect and modified their molecular packing patterns in the crystals. Alkoxyl substitutedCM1 -CM3 exhibited boosted luminescence in solution and the solid state simultaneously. CM2 giving fluorescence quantum yields as high as 73.2% and 96.7% in solution and the solid state, respectively.