RECENTLY we have reported1 the synthesis of organic ligands consisting of two mono-aza- 12-crown-4 rings linked together by a single alkylene bridge between nitrogen atoms. Very enhanced complexation of alkali cations was observed, in particular of the Na cation when the bridge is -CH,CH,- ... Published on 01 January 1981. Downloaded by google on 20/02/2016 21:38:24. ... View Article Online / Journal Homepage / Table of Contents for this issue