A series of four azocalixarene derivatives bearing bipyridyl units and additional functional groups such as amide, ester and pyridine at the phenolic oxygen atoms were synthesized. The conformational properties of these ligands were obtained by 1 H NMR spectroscopy. Moreover, extraction properties towards different metals of 1, 2, 4, 5 and 6 using liquid-liquid extraction by atomic absorption spectrometry have been studied and exhibit Ag 1 selectivity.Scheme 1 Synthetic pathway of hetero-functionalized azocalix[4]arene incorporating both bipyridyl and pyridyl groups 2.
The synthesis of a series of chromogenic calix [4]arenes derivatives is described. Different chelating agents as ester, amide, bipyridyl and bithiazolyl moieties were grafted on the lower rim of p-phenylazocalix [4]arenes. In addition, a calixarene bearing two b-ketoimine groups has been synthesized. Their extraction properties were studied by liquid-liquid extraction. The results show that the ester/amide azocalix [4]arene derivatives have an affinity for alkali metal ions whereas b-ketoimine calix [4]arene exhibits a good affinity and selectivity towards Pb 2+ . In the case of biheterocyclic calixarenes, bipyridyl and bithiazolyl derivatives have a similar behavior with a slight affinity for Cu 2+ and Ag + . Their homologous thiacalix [4]arene derivatives give the best extraction percentages and have the best efficiency for the extraction of Cu 2+ and Ag + .
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.