Hierarchical Assembly of an Interlocked M8L16 Container

The self-assembly of eight Pd-II cations and sixteen phenanthrene-derived bridging ligands with 60 degrees bite angles yielded a novel M8L16 metallosupramolecular architecture composed of two interlocked D-4h-symmetric barrel-shaped containers. Mass spectrometry, NMR spectroscopy, and X-ray analysis revealed this self-assembled structure to be a very large Hopf link catenane featuring channel-like cavities, which are occupied by NO3- anions. The importance of the anions as catenation templates became imminent when we observed the nitrate-triggered structural rearrangement of a mixture of M3L6 and M4L8 assemblies formed in the presence of BF4- anions into the same interlocked molecule. Furthermore, the densely packed structure of the M8L16 catenane was exploited in the preparation of a hexyloxy-functionalized analogue, which further self-assembled into vesicle-like aggregates in a reversible manner.