Two
bis(2-oxy-1,3-propylenedithio)tetrathiafulvalene-con-separate components upon oxidation of the TTF-type unit, as a result of disruption of the CT interaction and electrostatic taining acyclic polyethers and two macrocyclic polyethers, each incorporating one bis(2-oxy-1,3-propylenedithio)tetra-repulsion between the tetracationic host and the newly formed monocationic guest. The subsequent reduction of the thiafulvalene unit and one p-phenylene ring, have been synthesized. The two acyclic polyethers are bound by guest to its neutral state affords back the pseudorotaxanetype complex restoring the original equilibrium. The results cyclobis(paraquat-p-phenylene) with pseudorotaxane geometries in solution. The two macrocyclic polyethers have obtained from electrochemical experiments are consistent with the reversible, redox-driven dethreading/rethreading been mechanically interlocked with this tetracationic cyclophane to form [2]catenanes in a kinetically controlled process observed by 1 H-NMR spectroscopy. Variabletemperature 1 H-NMR-spectroscopic investigations have self-assembly process. The X-ray crystallographic analysis of one of the two [2]catenanes and 1 H-NMR-spectroscopic revealed two dynamic processes, both involving the relative movements of the mechanically interlocked components in studies of both compounds showed that the p-phenylene ring of the macrocyclic polyether is located inside the cavity of the [2]catenanes. The two consecutive oxidation processes involving the TTF-type unit, observed electrochemically, are the tetracationic cyclophane, while the bis(2-oxy-1,3propylenedithio)tetrathiafulvalene unit resides alongside.
displaced toward more positive potentials compared with the free cyclic polyethers. The two reversible two-electron The [2]pseudorotaxanes and [2]catenanes show broad bands around 780 nm, arising from the charge-transfer (CT) reduction processes, characteristic of free cyclobis(paraquatp-phenylene), separate into four reversible one-electron interaction between the electron-donor tetrathiafulvalene-(TTF-)type unit and the electron-acceptor units of the processes because of the topological difference between the "inside" and "alongside" electron-acceptor units in the tetracationic cyclophane. 1 H-NMR-spectroscopic studies have shown that the [2]pseudorotaxanes dissociate into their [2]catenane.
nal stimuli. The observation that TTF Ϫ in its neutral state