New fluoroionophores for alkali-metal cations based on tetrameric calixarenes

Abstract

The synthesis and fluorescence behaviour of two novel fluorescent calix[4]arenes containing four anthracene moieties on the lower rim are described. The calixarenes exhibit an optically selective fluorescent response to complexation with group 1 metal cations. Interesting optical responses to Li⁺, Na⁺ and K⁺ have been found with the tetraester derivative 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.

¹ H NMR studies enable the 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 material.