Synthesis of a water-soluble 2,2'-biphen[4]arene and its efficient complexation and sensitive fluorescence enhancement towards palmatine and berberine.

A water-soluble 2,2'-biphen[4]arene (2,2'-CBP4) containing eight carboxylato moieties was synthesized and characterized. Its complexation behavior towards two alkaloids, palmatine () and berberine (), was investigated by means of fluorescence and H NMR spectroscopy in aqueous phosphate buffer solution (pH 7.4).