Chemosensor towards metal ions

Fluorescent chemosensors for the detection of heavy metal ions by a simple fluorescence tum-on (off-on) or quenching (on-ofi) are a fundamental tool for a rapid and nondestructive analysis of biochemical and environmental matrices (2007CSR993). A hot topic is the des p of selective sensors for Hg, one of the most hazardous pollutants of the environment. In this context, a new tren-based starburst molecule containing fluorinated 1,2,4-oxadiazoles as fluorophores has been synthesized and its sensing behavior towards several metal cations has been investigated by UV/Vis, fluorescence. 

Copper-catalyzed azide-alkyne cycloaddition has been used to couple the phenazine luminescent probe and an Af,Af-bis(2-picolyl)amine moiety in a 75% yield by using copper acetate (0.01 mol%) and sodium ascorbate in CH3CN/H2O (10 1) [94]. The cycloaddition of l,3-diethynyl-6-fluoroisoquinohne with 1-(2-azidoethyl)pyrrohdine has been applied to the synthesis of a soluble click fluorescent chemosensor (Scheme 3.5). The molecule displays good sensitivity toward heavy and transition metal ions such as Fe ", or Cu in water at pH 7.0 [95]. 

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