The efficiency of a series of amino-azacryptands for encapsulation and extraction of the oxoanions pertechnetate and perrhenate from aqueous solution is investigated and compared with that of their open-chain counterparts. The aqueous formation constants for oxoanion association with the cryptands were determined by pH potentiometry and/or NMR, and X-ray analysis of single crystals provides evidence for encapsulation. The extractabilities could not be explained solely on the basis of ligand lipophilicity; the level of protonation also plays an important role.
研究了一系列氨基偶氮隐含物从水溶液中封装和萃取过硫酸盐和过铼酸盐氧阴离子的效率,并将其与开链对应物的效率进行了比较。通过 pH 电位法和/或核磁共振法测定了氧阴离子与隐晶质结合的水形成常数,单晶体的 X 射线分析提供了封装的证据。萃取能力不能仅根据配体的亲油性来解释,质子化水平也起着重要作用。