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A Selective Metal–Ligand Fluorescent Chemosensor for Dihydrogen Phosphate via Intermolecular Excimer Formation in Water



Two new anthrylpolyamine ligands and their zinc complexes 2Zn and Zn have been synthesized. The recognition ability of 2Zn and Zn towards inorganic anions was studied by fluorescence spectroscopy in water at physiological pH values. The receptor 2Zn displays an excellent selective fluorescent enhancement of the excimer emissive peak with H2PO4 that is absent with other inorganic anions such as SO42–, NO3, HCO3, AcO, F, Cl, Br and I. The obvious excimer formation can be explained by 2+2-type binding between 2Zn and H2PO4, which was confirmed by electrospray ionization data. The sensitive fluorescent response and excellent selectivity show that receptor 2Zn can be used as a fluorescent chemosensor for the H2PO4 anion under physiological pH conditions. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)