9,10-Diarylanthracenes as stable electrochemiluminescent emitters in water.

Two hydrophilic diarylanthracenes, explicitly 9,10-bis(N-methylimidazolium-3-propoxyphenyl)anthracene (DAA1) and 9,10-bis(N-methylimidazolium-3-propoxy-2,6-dimethylphenyl)anthracene (DAA2), are synthesized and fully characterized. Both are found to be soluble in aqueous medium and to exhibit optical properties similar to those of the parent 9,10-diphenylanthracene, whose solubility is virtually negligible in water. The detailed analysis of their photochemical stability as well as electrochemical and electrochemiluminescent properties reveals that the sterically highly shielded anthracene DAA2 shows inertness toward reactions with singlet oxygen and OH(-) ions during photo- and electrochemical initiation and stable ECL emission in aqueous medium.