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RESEARCH PRODUCT

Aza–oxa macrocyclic ligands functionalised with naphthylmethyl fluorescent groups

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Abstract Compounds L 1 and L 2 were obtained by reaction of 2-(bromomethyl)naphthalene with 1,4,10-trioxa-7,13-diazacyclopentadecane and 1,4,7-trioxa-10-azacyclododecane, respectively. These receptors contain aza–oxa crowns attached covalently to fluorescent groups. The protonation and coordination behaviour of L 1 and L 2 against metal ions has been studied in dioxane:water (70:30 v/v, 25°C, 0.1 M potassium nitrate) using potentiometric methods. All metal ions studied form complexes with L 1 and L 2 with the logarithm of the formation constants L+M 2+ =[M(L)] 2+ in the sequence Cd 2+ ≅Pb 2+ , Zn 2+ 2+ for L 1 and Zn 2+ 2+ 2+ 2+ 2+ for L 2 . The fluorescent behaviour of L 1 and L 2 was studied in dioxane:water (70:30, v/v) and in acetonitrile in the presence of Ni 2+ , Cu 2+ , Zn 2+ , Cd 2+ , Hg 2+ , Pb 2+ cations and chloride, bromide, sulfate and phosphate anions. The most significant feature is the quenching of the fluorescence produced by Cu 2+ in acetonitrile.