A Selective and Sensitive Hg2+ Aminonaphthalimide-aza-crown-ether Cellular Chemosensor
Crown ether ionophores linked to napthalimide fluorophores provide a powerful and versatile class of fluorescent chemosensors. Here we demonstrate the unusual Hg2+ ion selectivity of an aza-crown ether ionophore linked to a 4-aminonapthalimide by 1,4-phenylenediamine. Binding, computational, and fluorescence studies reveal an intramolecular charge transfer mechanism. The sensor demonstrates exceptional selectivity for Hg2+ in aqueous ethanol and detects both Hg2+and Zn2+ in aqueous acetonitrile. The sensor's Hg2+ sensitivity is retained in live cells at biologically relevant concentrations of Hg2+, making it a potentially versatile and convenient tool for environmental and biological assay and monitoring applications.