Self-assembled [2]catenanes exhibiting highly selective translational isomerism

Abstract

Template-directed synthesis is used to construct two isomeric [2]catenanes incorporating the macrocyclic polyether, (paraphenylene-metaphenylene)-33-crown- 10, and either (i) cyclobis (paraquat-p-phenylene) or (ii) 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-temperature ¹H NMR spectroscopy) states–the one in which a hydrouinone, rather than a resorcinol, ring is located inside the cavities of the isomeric tetracationic cyclophanes.