Dynamics of mechanically bonded macrocycles in radial hetero[4]catenane isomers

Radial [4]catenane isomers in which the dynamics of the interlocked macrocycles are encoded by the covalent structure of the central macrocyclic backbone are described. Shuttling motion of the interlocked β-cyclodextrin was found to be dependent on both the position and interaction strength of the interlocked cucurbit[6]urils on the central macrocycle. This work demonstrates that the dynamics of different mechanically bonded macrocycles in a hetero[n]catenane can be coordinated complementarily, suggesting the possible exploitation of higher-order [n]catenanes as the next level molecular machines in which more complex tasks can be performed with sophisticated intramolecular motions.