Controlled Self-Assembly and Multistimuli-Responsive Interconversions of Three Conjoined Twin-Cages.

Stimuli-responsive structural transformations between discrete coordination supramolecular architectures not only are essential to construct smart functional materials but also provide a versatile molecular-level platform to mimic the biological transformation process. We report here the controlled self-assembly of three topologically unprecedented conjoined twin-cages, i.e., one stapled interlocked PdL cage () and two helically isomeric PdL cages ( and ) made from the same cis-blocked palladium corners and a new bis-bidentate ligand (). While cage features three mechanically coupled cavities, cages and are topologically isomeric helicate-based twin-cages based on the same metal/ligand stoichiometry. Sole formation of cage or a dynamic mixture of cages and can be controlled by changing the solvents employed during the self-assembly. Structural conversions between cages and can be triggered by changes in both temperature/solvent and induced-fit guest encapsulations. Well-controlled interconversion between such topologically complex superstructures may lay a solid foundation for achieving a variety of functions within a switchable system.