Controlling Translational Isomerism in [2]Catenanes

The template-directed synthesis of the [2]catenane 1-4 PF6, in which a macrocyclic polyether is encircled by a tetracationic cyclophane, has been achieved in 58% yield. Of the four possible translational isomers, that shown on the right dominates in solution at low temperatures, according to 1H NMR spectroscopy. This isomer is the only one observed in the solid state.