Highly optically selective and electrochemically active chemosensor for copper (II) based on triazole-linked glucosyl anthraquinone

A novel triazole-linked acetyl-β-N-glucosyl anthraquinone 1 was conveniently synthesized through one-step click chemistry. The functionalized glycoconjugate (1) exhibited a remarkable blue shift absorption and quenching fluorescence in the presence of trace amounts of Cu2+, presumably attributable to intramolecular charge transfer (ICT), which also displayed high selectivity over a series of other metal cations tested in acetonitrile. The result yielded by fluorescence spectroscopy titration suggested a 2:1 ligand-to-metal complex which was further demonstrated by NMR spectroscopy titration. Moreover, the addition of Cu2+ to 1 also significantly altered its electrochemical behavior which was reflected via differential pulse voltammetry (DPV) measurements. Such optically and electrochemically detectable metal-mediated sugar derivatives could be further used as biosensors for the recognition of multivalent carbohydrate-protein interactions.