A NEUTRAL UPPER TO LOWER RIM LINKED BIS-CALIX[4]ARENE RECEPTOR THAT RECOGNIZES ANIONIC GUEST SPECIES

The molecular recognition of anionic guest species by positively charg ed or electron deficient neutral abiotic receptor molecules is an area of intense current interest(1), The importance of favourable amide GO -NH hydrogen bonding interactions for anion binding has recently been exploited by ourselves(2) and others(3) in the design of calix[4]arene anion receptors which are still relatively rare. We report here the s ynthesis and preliminary anion coordination studies of a novel bis-cal ix[4]arene receptor 7 in which the upper rim of one calix[4]arene moie ty is covalently linked via amide bonds to the lower rim of another in a head to tail fashion(4).