bis-Methoxycarbonylmethoxy derivatives capable of reacting with the surface of aminopropylated silica gel with the formation of chemically and thermally stable amide bonds were obtained by regioselective distal dialkylation of hydroxyl groups of phosphorylated tetrahydroxycalix[4]arenes in high yields. It was found that phosphine oxide and phosphonate P=O groups localized on the upper rim cooperatively bind Eu3+ cations and effectively sorb them from nitric acid solutions.

中文翻译：

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用四磷酸化双甲氧羰基甲氧基杯[4]芳烃对氨基丙基化硅胶进行表面改性以有效吸附铕(III)

通过对磷酸化四羟基杯[4]芳烃的羟基进行区域选择性远端二烷基化，获得了能够与氨基丙基化硅胶表面反应并形成化学和热稳定酰胺键的双甲氧羰基甲氧基衍生物。发现位于上部边缘的氧化膦和膦酸酯 P=O 基团协同结合 Eu3+ 阳离子并有效地从硝酸溶液中吸附它们。