NEW FLUOROIONOPHORES FOR ALKALI-METAL CATIONS BASED ON TETRAMERIC CALIXARENES

The synthesis and fluorescence behaviour of two novel fluorescent cali x[4]]arenes containing four anthracene moieties on the lower rim are d escribed. The calixarenes exhibit an optically selective fluorescent r esponse to complexation with group 1 metal cations. Interesting optica l responses to Li+, Na+ and K+ have been found with the tetraester der ivative and high affinity for Na+ ions with the tetraamide derivative. They may prove to be useful components for the fabrication of optical sensors for the determination of these ions. H-1 NMR studies enable t he molecular basis for differences in the optical behaviour of the two ligands to be understood at least partially, and perhaps explain why the tetraamide calixarene has better potential as an Na+ sensor materi al.