Synthesis and alkali metal picrate extraction capabilities of a 4-oxahexacyclo[5.4.1.02,6.03,10.05,9.08,11]dodecane-derived cryptand.: A new ionophore for selective ion complexation

The synthesis of a novel cage-functionalized cryptand, 5, and the X-ray 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 structure 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 obtained for 10, an adamantane-containing analog of 5. With the possible exception of its ability to extract K+ picrate, there appears to be relatively little: difference between the alkali metal picrate extracting capabilities of host molecule 10 and a corresponding monocyclic model system, i.e., N,N'-diethyl-4,13-diaza-18-crown-(6) (6). (C) 1998 Elsevier Science Ltd. All rights reserved.