Functionalized azobenzocrown ethers as sensor materials—The synthesis and ion binding properties

New 13- and 16-membered azobenzocrown ethers with aromatic amino, amide, ether–ester or ether–amide residue in para position to an azo moiety were obtained. Acid–base properties and ion binding ability of the colored compounds were studied by spectroscopic methods: UV–vis, fluorimetry and 1H NMR spectroscopy. Selected azobenzocrowns were tested as ionophores in ion-selective membrane electrodes (ISEs) – classic and miniature all solid state. The X-ray structure of the sodium complex of ether–ester derivative of 16-membered azobenzocrown was presented.