A simple fluorescent chemosensor for alkaline-earth metal ions

In acetonitrile solutions, the deprotonated form of 1-pyrenebutyric acid (1 ) forms 1:2 (metal:ligand) complexes with Zn2+ Cu2+, Fe2+ Fe3+, and earth a lkali metal ions. The complexation process leads two pyrene moieties in clo se contact, so that dimers are formed, causing strong changes in the absorp tion and fluorescence spectra. Taking advantage of these changes, very low concentrations of earth alkali metal ions can be detected, suggesting 1 as a good prototype of a new family of fluorescent sensors. (C) 2000 Elsevier Science S.A. All rights reserved.