THE CONTROL OF TRANSLATIONAL ISOMERISM IN CATENATED STRUCTURES

The self-assembly in 50% yield of a [2]-catenane, comprised of 1,5-nap htho-paraphenylene-36-crown-10 and the cyclobis(paraquat-p-phenylene) tetracation, is described. This interesting compound has been characte rized electrochemically and photochemically, as well as by FARMS and N MR spectroscopy, and found to exist in solution as a mixture of two tr anslational isomers depending on whether the hydroquinol ring or the 1 ,5-dioxynaphthalene unit of the crown ether occupies the central cavit y of the tetracationic cyclophane. The equilibrium ratio of these two isomers is shown to be highly dependent on the polarity of the solvent in which the catenane is dissolved.