Communication between Components in Metal-Directed Assemblies of Oriented Calix[6]arene-Based Pseudorotaxanes and Rotaxanes

Oriented calix[6]arene-based pseudorotaxanes and rotaxanes where the axial component bears a terpyridine ligand as a stopper positioned at the upper rim of the calixarene have been synthesized. The binding ability of the terpyridine unit present in the axle toward zinc salts is affected by the presence of the wheel, its distance with respect to the calix[6]arene upper rim, and the nature of the counterion of the zinc salt employed. Metal coordination at the terpyridine unit changes the electrochemical behavior of the 4,4'-bipyridinium unit of the axle inside the wheel in both the pseudorotaxanes and rotaxanes.