Fig. 5. A schematic summary of the reduction-induced motions in the potential viologen-based molecular lassos 1 6+ and 2 6+. (a) Conversion of 1 6+ to its reduced state, 1 3(˙+), by treating with Zn dust, where the self-entanglement is prohibited because of the disfavoured steric repulsion and only a side-on interacting mode is allowed. (b) Conversion of 2 6+ to its reduced state, 2 3(˙+), by treating with Zn dust, which triggered a self-entanglement process to form a lasso-like pseudo[1]rotaxane with a noose-like conformation, as a result of strong intramolecular radical-pairing interactions.
