Fluorescent Chemosensors for Cu2+ Ions: Fast, Selective, and Highly Sensitive

Low cross-sensitivity for other metal ions and the ability to detect nanomolar concentrations of Cu2+ ions are the exciting properties of fluorescence sensors in which a fluorophore and a chelating group are discrete subunits of the same molecule. The spatial separation offers considerable flexibility in design, which is a prerequisite for the optimization of sensor properties. The activity of the “chemodosimeter” 1 of Czarnik et al. is based on the Cu2+-induced hydrolysis of the hydrazide group and the formation of fluorescent rhodamine B.