Adjusting the Dynamism of Covalent Imine Chemistry in the Aqueous Synthesis of Cucurbit[7]uril-based [2]Rotaxanes.

The self-assembly of [2]rotaxane has been achieved in aqueous media at pD 4 by the simultaneous threading into CB[7] of an appropriate axle ended with acyl hydrazine groups and its concurrent capping with two molecules of a triphenylphosphonium aldehyde as stoppers. The dynamism of the rotaxane has been demonstrated under acidic conditions and can be diminished by solvent swapping, pH modulation, or, surprisingly, the removal of the carbonyl groups on the axle.