A novel asymmetric indolo[3,2-b]carbazole derivative containing benzothiazole and dimesitylboron units: Synthesis, photophysical and sensing properties

• A novel asymmetric indolo[3,2-b]carbazole compound.
• which incorporate a benzothiazole unit (electron-acceptor) and a dimesitylboron unit (electron-acceptor) to 2- and 8-position of indolo[3,2-b]carbazole (electron-donor) respectively.
• was investigated as a highly selective ratiometric fluorescence sensor with remarkable colour changes for fluoride ion.

A novel asymmetric acceptor–π-donor–π-acceptor compound, 2-benzothiazolyl-8-dimesitylboryl-5,11-dihexylindolo[3,2-b]carbazole (BDDICZ), has been successfully synthesized by introducing a benzothiazole (electron-acceptor) moiety and a dimesitylboron (electron-acceptor) group to 2-position and 8-position of indolo[3,2-b]carbazole (an electron-donor), respectively. The structure of BDDICZ was fully characterized by NMR, MS and elemental analysis and was studied by both experimental and theoretical methods. Our results demonstrate that BDDICZ is a sensitive ratiometric fluorescence probe which shows remarkable color change with fluoride ion (F−). The theoretical calculations confirm that BDDICZ can readily react with tetrabutylammonium fluoride (Bu4N+F−) to form an adduct of (Bu4N)+(BDDICZ·F)−. Moreover, BDDICZ possesses appropriate HOMO and LUMO energy states and a high fluorescence quantum yield, indicating its potential application as an ideal hole-transporting and/or light-emitting material in optoelectronic devices.

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