Spontaneous assembly of ten components into two interlocked, identical coordination cages

Supermolecules consisting of interlinked ring-like molecules (catenanes)1 are an interesting target for chemical synthesis both for their intrinsic interest as non-covalently bound but robust assemblies and because of the perspective they offer on materials chemistry2. Catenanes have been prepared by metal-ion templating3,4 and self-assembly through other non-covalent interactions5,6,7,8,9,10,11,12. Here we report the synthesis of a catenane composed not of two interlocking rings but of two cages. This structure is prepared by metal-mediated self-assembly13,14,15. The framework of each cage is assembled from five components: two tridentate ligands held together with three metal ions. Because each cage framework can bind an aromatic ring, two cage units will bind one another during their assembly process through the formation of a quadruple aromatic stack, giving rise to the ten-component interlocked supermolecule16,17.