Multicomponent Metallacages via the Integrative Self-Assembly of Pt(II) Nodes with Multiple Pyridyl and Carboxylate Ligands

In recent years, multicomponent self-assembly has emerged as a pivotal strategy in supramolecular chemistry, enabling the construction of artificial systems with enhanced functionalities that surpass those of individual molecular components. These assemblies have garnered significant interest due to their potential applications in molecular recognition, catalysis, and biomedical engineering. However, achieving precise control over the assembly process remains a significant challenge, as increased structural complexity often results in thermodynamic mixtures, limiting their practical applications. In this context, metal-coordination-driven multicomponent self-assembly has emerged as a promising strategy, as the moderate strength and good directionality of metal–ligand bonds ensure the formation of discrete supramolecular architectures with well-defined structures and geometries. Notably, the integration of pyridyl and carboxylate donors with cis-Pt(II) nodes offers an effective approach for constructing multicomponent metallacages. This method is particularly attractive due to its ability to enable precise heteroleptic assembly, along with the accessibility and tunability of the ligands, which impart desirable photophysical properties and potential anticancer activities.

This Account provides a comprehensive overview of our work on the design, preparation, and functionalization of multicomponent metallacages via the heteroleptic assembly of pyridyl and carboxylate ligands with cis-Pt(II) nodes. By strategically tailoring the ligand structures and adjusting the number of coordination sites, we have successfully constructed multicomponent metallacages with diverse geometries, including tetragonal and hexagonal prisms, triple-cavity ladders, truncated octahedra, and cyclic bis[2]catenanes, etc. In particular, we highlight the use of functional pyridyl ligands, such as tetraphenylethylene, hexaphenylbenzene, perylene diimide, and porphyrin derivatives, to explore the applications of these metallacages. Tetraphenylethylene and hexaphenylbenzene derivatives are propeller-shaped molecules with aggregation-induced emission properties, enhancing the emission of the metallacages both in solution and the solid state. Perylene diimide derivatives, with their electron-deficient, planar conjugated structures, contribute to strong emission in solution, thereby improving the host–guest chemistry and luminescent properties of the metallacages. Porphyrin derivatives, owing to their planar structures and excellent photosensitivity, endow the metallacages with significant photocatalytic capabilities. Additionally, other ligands, such as phenanthroline and triazine derivatives, have been employed to impart antibacterial and SO₂ adsorption properties, respectively, to the metallacages. Furthermore, metallacage-cross-linked supramolecular networks exhibit enhanced mechanical properties and superior processability, making them promising candidates for functional materials. At the conclusion of this Account, we address the challenges and future perspectives in the development of multicomponent metallacages. We believe that ongoing research in this field will significantly advance the understanding of metal-coordination chemistry, supramolecular chemistry, and the development of functional supramolecular materials.