The triply catenated systems are more intricate topologies that consists of two identical, mechanically interlocked coordination cage components with intriguingly complex architectures. A few triply interlocked catenanes have been successfully...

Despite recent efforts to advance host‐guest systems using discrete metal‐organic cages (MOCs) with non‐trivial topological geometries for molecular recognition, which is often mediated by non‐covalent interactions involving aromatic functional groups, the relative complexation of these so‐called π‐π interaction is still challenges of study, theory and modeling. Specifically, the ability of supramolecular interactions, for an example, π‐π stacking between guest substrates and MOCs as hosts, would easily control the host‐guest assemblies. By the assembly of host‐guest complexations with metal‐coordination driven strategy and π‐π interaction, here we show that the hierarchical combination of the newly metal‐organic cages with nanosized cavity (metallacage 1), which facilitates encapsulating guest molecules through supramolecular forces. Additionally, the electron‐donating (ED)/‐withdrawing (EW) functional groups of pyrene analogues, utilized as guest substrates, can enforce host‐guest assemblies with electron‐donor (D) and electron‐acceptor (A) interactions. We herein demonstrate that ED or EW group can promote host‐guest behaviors. By this new approach, we predict that the more stable host‐guest complexations will be accompanied by stronger D−A interactions. Three guest substrates, including 1‐hydroxypyrene, 1‐pyrenamine, and 1‐pyrenecarboxaldehyde, were chosen to systematically study this host‐guest system within 1, exhibiting well consistent with our hypothesis.

Metal‐organic cages (MOCs) are promising candidates for drug deliveries, catalysis, and host‐guest systems. In addition, their own finite cavities can control to the sizes and shapes of metal nanoparticles (MNPs), leading to promote their catalytic performance. Herein, we used half‐sandwich rhodium moieties with pyridyl ligands through coordination‐driven self‐assembly strategy and bridged‐unit (tpphz)‐mediated host‐guest complex formation in concert to produce a sufficient cavity with about 2.0 nm of size that facilitate to prepare controllably sizes and shapes of MNPs. Specifically, a metal‐organic cage 1, containing robust ligands (tpeb) and bridged units, has been successfully synthesized and fully characterized by several spectroscopic techniques. Its final structure was unambiguously confirmed by single‐crystal X‐ray diffraction (SCXRD). The pyridyl ligand units of 1 underwent noncovalent complexation with platinum nanoparticles to yield a Pt‐NPs@1 under UV‐visible irradiation of K2PtCl6. Moreover, UV and CV were carried out to determine the redox properties of 1 and Pt‐NPs@1, finding that Pt‐NPs@1 has a good redox property. Therefore, the supramolecular composites were used as catalysis for degradation of dye stuffs in aqueous solution, exhibiting good selectivity and activity.