SELF-ASSEMBLED [2]CATENANES EXHIBITING HIGHLY SELECTIVE TRANSLATIONALISOMERISM

Template-directed synthesis is used to construct two isomeric [2]caten anes incorporating the macrocyclic polyether, (paraphenylene-metapheny lene)-33-crown-10, and either (i) cyclobis(paraquat-p-phenylene) or (i i) cyclo(paraquat-p-phenylene)(paraquat-m-phenylene) as their tetrakis (hexafluorophosphates); these isomeric [2]catenanes are found to have a remarkable preference to exist as one translational isomer, both in the solid (by X-ray crystallography) and solution (by variable-tempera ture H-1 NMR spectroscopy) states-the one in which a hydroquinone, rat her than a resorcinol, ring is located inside the cavities of the isom eric tetracationic cyclophanes.