RUBIDIUM-SELECTIVE CHROMOIONOPHORES WITH N-(ARYLAZOALKENOYL)AZACORONAND STRUCTURE

The N-(arylazoalkenoyl)azacoronands 2a-2c have been synthesized by rin g-opening reaction of the dichloropyrazolin-5(4H)-one 1 with the corre sponding azacrowns. The structure of 2a was determined by X-ray analys is. In the presence of Rb+ salts the neutral solutions of 2a and 2b in acetonitrile or acetonitrile/water mixtures show a change of colour f rom yellow to red. Spectroscopic results of H-1-, H-2, C-13- and Rb-87 -NMR investigations indicate a complexation of the Rb ion between the crown and the phenolic OH group of 2b.