Abstract Benzo-crown ether based chemosensors linked by an amide bond at the 1-, 2-or 9- positions of anthracene rings were synthesized. Their complexation behavior with alkaline earth metal ions in acetonitrile was investigated using fluorescence, UV, and 1 H NMR spectroscopy. In the absence of a metal ion, all compounds showed only very slight fluorescence emissions (fluorescence 'off'state) because of intramolecular charge/electron ...
