The synthesis of a new series of beta-ketoimine calix[4]arene derivatives is described. The reaction of calix[4]arene or p-tert-butylcalix[4]arene with bromoacetonitrile or bromobutyronitrile afforded di-, tri-, and tetranitrile calixarene derivatives (3-8, 3a), which were then reduced into the corresponding amine (9-13, 3b). The condensation of these aminocalixarenes with acetylacetone led to six beta-ketoimine calix[4]arene derivatives (14-18, 3c) as a class of selective receptors toward transition metals. Molecular structures of 4, 7, and 17 have been determined by X-ray diffraction. The packing of 17 revealed a network of intramolecular and intermolecular hydrogen bonds. The complexation properties of receptors 15, 17, and 3c toward different metal ions have been investigated by UV-vis titrations in organic media. The stoichiometries of complexes with 17 were determined by both the mole ratio method and Job plots. These novel receptors selectively complex Cu2+, Hg2+, and Ag+. Moreover, the extraction properties of 17 toward cations have been studied by liquid-liquid extraction and atomic absorption spectrometry. Compound 17 has good affinity and selectivity toward Pb2+.

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The synthesis of a new series of chromogenic calix[4]arene derivatives is described. p-Tetrakis(phenylazo)calix[4]arenes substituted with tertiary amide groups at the lower rim were obtained. The O-substitution of 25,26,27,28-tetrahydroxy-11,23-bis(phenylazo)calix[4]arene (2) and 25,26,27,28-tetrahydroxy-5,17,11,23-tetrakis(phenylazo)calix[4]arene (3) to provide 26,28-bis{[(diethylamino)carbonyl]methoxy}-25,27-dihydroxy-11,23-bis(phenylazo)calix[4]arene (4), 26-{[(diethylamino)carbonyl]methoxy}-25,27,28-trihydroxy-5,11,17,23-tetrakis(phenylazo)calix[4]arene (5), 25,26,27,28-tetrakis{[(dialkylamino)carbonyl]methoxy}-5,11,17,23-tetrakis(phenylazo)calix[4]arene [alkyl = ethyl (6a), methyl (7)] and 26,28-bis{[(diethylamino)carbonyl]methoxy}-25,27-dihydroxy-5,11,17,23-tetrakis(phenylazo)calix[4]arene (8a) have been carried out by treatment of the precursors 2 and 3 with