Thf2 synthesis of several macrocycles containing tvo bipyrazollc subunits, with diffemnt cavity sims and with donorgroup-bearing side arms atiyuhid, is reported. Thafr alkali cation binding ability has bean studisd from two aspects : extraction and transport through an artificial liquid msmbrane. Nacrocycles described here show a high selectivity towards Li+ and Na+ cations; furthermore one of them is remrkably well adapted to extract selectivefy and to transport efficiently the lithium cation in competitive conditions. Oxygen donor macrocycles such as crown ethers are well known to give strong complexes ahst exclusively with alkali and alkaline earth ions. Ry contrast, saturatad and unsaturated polyazamacrocycles show a high affinity for transition matal ions. 192 Macrocycles containing nitrogen heterocyclic units concern mainly porphyrins and phthalocyanines2 butsoraa of them incorporating pyridine units have also been described. 1a.b.f.g These all complex transition metal cations but lately mrcropolycyclic ligands containing 2,2'-bipyridine and l,lO-phenanthroline 3a,c subunits have been reported to give stable sodium or lithium3b'c ion complexes. Soms studies have been dons on mixed 0 and N containing macrocycles 1a*b*f'4 but none of these bss high affinity for alkali and tranaftion metal ions.
For some tima we have been interested in polypyrazolic mscrocycles: the novelty of these structures containing nitrogen donor sites is that they can complex alkali ions 5-8 aa well as transition meta). ions such as ruthenium(II).9'10
In this paper we describe the synthesis and babaviour of a series of new macrocycles containing two bidentate bipyrazolic entities towards alkali cations (their complexation with transition matal ions will be reported elsewhere).
The following molecules have been obtained (Py= Pyridine, Pa-Pyrarine)