Azadithiacrown ether based ditopic receptors capable of simultaneous multi-ionic recognition of Ag+ and Hg2+

Novel azadithiacrown ether containing bis(styryl)pyridinium dyes were synthesized and their complexation with different transition metal cations was investigated. It was found that the compounds give a selective ratiometric optical response in the presence of silver (I) and mercury (II) cations. Evidence was given for the occurrence of two stoichiometries: LM and LM2. Moreover, the formation of a mixed complex [Ag+center dot L center dot Hg2+] containing both Ag+ and Hg2+ cations simultaneously was demonstrated. Optical spectroscopy was used to estimate stability constant values of the complexes, NMR spectroscopy data allowed us to offer a model of spatial arrangement of the obtained species. (C) 2012 Elsevier Ltd. All rights reserved.