Vapour-driven crystal-to-crystal transformation showing an interlocking switch of the coordination polymer chains between 1D and 3D

A reversible transformation between 1D coordination polymer chains and 3D mechanically interlocked structures, which involves interlocked open and closed linkages based on the [Cd(BCbpe)Cl₂] chain, has been achieved through vapour driving. Neither the coordination mode nor composition of the 1D chain undergoes any change during the reversible rearrangement of atoms generated by the breaking/formation of the coordination bonds. The cation-π interaction pair plays a crucial role in transferring structural information, which may serve as a memory matrix and axle to assist the molecules to undergo a flip-flop motion with high synergy.