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Water‐Soluble Distyrylbenzenes: One Core with Two Sensory Responses—Turn‐On and Ratiometric
Author(s) -
Tolosa Juan,
Bryant Jonathan J.,
Solntsev Kyril M.,
Brödner Kerstin,
Tolbert Laren M.,
Bunz Uwe H. F.
Publication year - 2011
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201102402
Subject(s) - protonation , chemistry , fluorescence , aniline , titration , zinc , carboxylate , aqueous solution , turn (biochemistry) , photochemistry , ligand (biochemistry) , blueshift , medicinal chemistry , inorganic chemistry , stereochemistry , organic chemistry , receptor , ion , biochemistry , physics , quantum mechanics , optics , photoluminescence
The synthesis of four water‐soluble distyrylbenzenes (compounds 1 – 4 ) 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 b – 3 b in water reveal unexpected protonation sequences upon titration: compound 1 b is green–yellow 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.