Synthesis and spectral properties of new fluorescent probes for potassium

Studies on the preparation and properties of two new. selective fluorescent probes CD18, 1 and C18, 2 for potassium are described. The probes incorporate the 1.10-diaza-18-crown-6 chelating group for the ion and the coumarin group as the fluorophore. The probes are compared with the known reagent PBFl. CD18 shows considerably greater selectivity for potassium over sodium than PBFl.