Calix crowns derived from para-bridged calix[4]arenes

Two calix[4]arenes, bridged by aliphatic chains of five and eight carbon at oms spanning two opposite para positions, have been converted into their 1, 3-crown ether derivatives by reaction with tetraethylene and pentaethylene glycol ditosylates, of the two possible 1,1,3-crown derivatives, only the f ormation of those isomers is observed in which the phenolic units connected at the para positions are etherified. This has been established in one cas e by a single-crystal X-ray analysis. Preliminary results for the extractio n of selected alkali and alkaline-earth metals are reported.