Molecular design of a PET-based chemosensor for uronic acids and sialic acids utilizing a cooperative action of boronic acid and metal chelate

To exploit new artificial receptors for detection of uronic acids and sialic acids in an aqueous system a novel fluorescent chemosensor molecule bearing both o-aminomethylphenylboronic acid group for diol binding and 1,10- phenanthroline-Zn(II) chelate moiety for carboxylate binding has been synthesized. The saccharide-binding process can be conveniently monitored by a fluorescence change which occurs by the photoinduced electron-transfer (PET) mechanism through a unit integrated in this molecule. Fluorescence measurements indicate that association for commonly occurring monosaccharides is little affected by Zn(II) addition whereas that for uronic acids or sialic acids is enhanced in the presence of Zn(II) owing to the two-points interaction. pH Dependence, stoichiometry of the complexes, and complexation modes have been examined. This artificial receptor shows substantial affinity toward uronic acids and sialic acids in aqueous methanol solution.