SYNTHESIS AND ALKALI-METAL PICRATE EXTRACTION CAPABILITIES OF A 4.1.0(2,6).0(3,10).0(5,9).0(8,11)]DODECANE-DERIVED CRYPTAND - A NEW IONOPHORE FOR SELECTIVE ION COMPLEXATION

The synthesis of a novel cage-functionalized cryptand, 5, and the X-ra y crystal structure of its 1:1 complex with Na+, i.e. 4, are reported. Host molecule 5 displays high avidity toward Na+ and K+ picrates and appears to extract these cations selectively. The X-ray crystal struct ure of 4 clearly indicates that Na+ is bonded to all seven Lewis base centers (i.e., nitrogen and oxygen atoms) in the complex. In addition, the corresponding alkali metal picrate extraction profile was obtaine d for 10, an adamantane-containing analog of 5. With the possible exce ption of its ability to extract K+ picrate, there appears to be relati vely little: difference between the alkali metal picrate extracting ca pabilities of host molecule 10 and a corresponding monocyclic model sy stem, i.e., N,N'-diethyl-4,13-diaza-18-crown-(6) (6). (C) 1998 Elsevie r Science Ltd. All rights reserved.