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

Abstract

Abstract Two new anthrylpolyamine ligands and their zinc complexes 1· 2Zn and 2· Zn have been synthesized. The recognition ability of 1· 2Zn and 2· Zn towards inorganic anions was studied by fluorescence spectroscopy in water at physiological pH values. The receptor 1· 2Zn displays an excellent selective fluorescent enhancement of the excimer emissive peak with H 2 PO 4 – that is absent with other inorganic anions such as SO 4 2– , NO 3 – , HCO 3 – , AcO – , F – , Cl – , Br – and I – . The obvious excimer formation can be explained by 2+2‐type binding between 1· 2Zn and H 2 PO 4 – , which was confirmed by electrospray ionization data. The sensitive fluorescent response and excellent selectivity show that receptor 1· 2Zn can be used as a fluorescent chemosensor for the H 2 PO 4 – anion under physiological pH conditions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)