Eight proton di-ionisable diacid conformers of nano-baskets including 25,26-di(carboxymethoxy)calix[4]arene-crown-3, -crown-4, -crown-5 and -crown-6 in the cone conformation have been synthesised and shown to extract lanthanide cations effectively. Their selectivities were greatly influenced by the acidity of the solution and the conformations of the calix-crown. The extraction loading was improved by having the p-tert-butyl-moiety in the upper rim. The scaffold bearing the crown-4 ether moiety showed the least loading, while scaffolds with crown-3- and crown-5-ether moieties had the best selectivities.
我们合成了八种质子可二离子化的二酸纳米篮构象,包括 25,26-二(羧基甲氧基)钙[4]烯-crown-3、-crown-4、-crown-5 和 -crown-6 锥构象,并证明它们能有效地萃取镧系阳离子。它们的选择性在很大程度上受溶液酸度和钙钛矿冠构象的影响。将对叔丁基分子置于上边缘可提高萃取负荷。带有冠-4-醚分子的支架的负载量最小,而带有冠-3-和冠-5-醚分子的支架的选择性最好。