A series of pyrazine-based calix[4]arene extractants was prepared by a stepwise functionalization, comprising palladium-catalyzed exhaustive cross-coupling of di- and tetrasubstituted calix[4]arenes bearing chloropyrazine moieties. The extraction behavior of the synthesized ligands was studied on Am–Eu mixtures under acidic feed conditions similar to those prevailing in nuclear wastes. Phosphorylpyrazine-bearing extractants exhibited a very high acid resistivity and a high affinity for americium giving D values as high as 794 at pH 1. The synergistic effect of the chlorinated cobalt bis(dicarbollide) anion [(B9C2H8Cl3)2Co]− (CCD-anion), as well as the effect of the calix[4]arene platform compared to monovalent ligands, was investigated. The presence of 1 mM CCD resulted in a 105 times increase in the D value.
通过
钯催化含有
氯吡嗪分子的二取代和四取代
钙[4]炔的穷举交叉偶联,采用逐步官能化的方法制备了一系列
吡嗪基
钙[4]炔萃取剂。在类似于核废料中普遍存在的酸性进料条件下,对合成
配体在
氨-
铀混合物中的萃取行为进行了研究。含
磷吡嗪的萃取剂表现出极高的耐酸性和对
镅的高亲和性,在 pH 值为 1 时,D 值高达 794。 研究了
氯化钴双二碳环阴离子[(
B9C2H8Cl3)2Co]-(CCD 阴离子)的协同效应,以及
钙[4]炔平台与单价
配体相比的效应。1 mM CCD 的存在使 D 值增加了 105 倍。