Synthesis and photophysical properties of a 2,2′-bianthracene-based receptor bearing two aza-15-crown-5 ethers for naked-eye detection of barium ion

As a novel chromofluorophore, 9,9'-dimethyl-2,2'-bianthracene 3 has been successfully synthesized by reductive coupling of 2-chloro-9-methylanthracene. Absorbance and fluorescence maxima of 3 can be shifted to visible-region comparing to the former 2,2'-binaphthyl-based receptors. Receptor 2 bearing aza-15-crown-5 moieties via methylene spacer provides selective UV-vis and fluorescence responses for Ba2+ due to the restriction of the conformational change through the formation of an intramolecular sandwich-complex by two azacrown ethers, resulting in the presence of Ba2+ that can be detected by naked eye in aqueous acetonitrile. (c) 2010 Elsevier Ltd. All rights reserved.