科研之友
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摘要
The synthesis of four water-soluble distyrylbenzenes (compounds 14) is reported. Their acidochromicity in aqueous media was investigated. Blue shifts and increases in the quantum yields were observed as a general response. The pH-dependent photophysics of 1?b3?b in water reveal unexpected protonation sequences upon titration: compound 1?b is greenyellow fluorescent at high pH (10) but becomes very weakly fluorescent between pH 5 and pH 3, whereas below pH 2 strong blue fluorescence is observed. This behavior can be explained in terms of the interplay in the protonation of aniline and of the carboxylate groups. In compound 4, a higher basicity of the amino group is observed and ratiometric fluorescence change takes place upon protonation or on reaction with zinc salts in water. Compound 4 can therefore act as a weak ratiometric zinc ligand in water, even though it has only a dimethylamino unit as a binding motif.
- 出版日期2011-12
