2-Aza-1,3-butadiene ligands for the selective detection of Hg2+ and Cu2+ ions

Abstract

We report a set of novel receptors with the structural feature of having an naphthyl-, pyrenyl- or ferrocenyl subunits, directly linked to a 2-aza-1,3-butadiene moiety which, in general, can be used for the rapid and selective detection of Hg2+. After coordination with this metal cation, the derivatives having two different signaling units, such as a fluorophore and a redox moiety, undergo significant changes not only in their oxidation potentials but also in their UV-vis and emission spectra. Interestingly, in such cases addition of Cu2+ cation promotes the oxidation of the free ligands. By contrast, pyrenyl derivative 10 selectively senses both Hg2+ and Cu2+ through two different channels: colorimetric and fluorescent. Furthermore, the association constants for the 1:1 complexes formed as well as the detection limits for the analysis of Hg 2+ and Cu2+ are also reported. These findings are not only a supplement to the detecting methods for these pollutant metal ions, but also adds new merits to the chemistry of the 2-aza-1,3-butadiene derivatives.