Metallacycle/Metallacage‐Cored Fluorescent Supramolecular Assemblies with Aggregation‐Induced Emission Properties

Abstract Fluorescent supramolecular assemblies have attracted significant attention for their application as bioimaging agents, biological and chemical sensors, light‐emitting materials, and gene and drug vectors. The introduction of supramolecular coordination complexes constructed by the spontaneous formation of dative metal–ligand bonds through coordination‐driven self‐assembly into fluorescent supramolecular assemblies is of particular interest. This is because the introduction of metal coordination renders the synthesized assemblies excellent stability in addition to providing unique emissions that are different from the fluorescent ligands or metal ions. The discovery of aggregation‐induced emission (AIE), wherein the fluorophores are nonfluorescent in the molecular state, but become highly emissive in the aggregate state, presents new chances for fluorescent supramolecular assemblies since such assemblies are often required to be employed at high concentrations or in the solid state. This progress report provides a summary of the recent design, construction, and application of metallacycle/metallacage‐cored fluorescent supramolecular assemblies based on coordination‐driven self‐assembly, wherein the assemblies exhibit AIE properties. Example applications discussed in detail include light‐emitting materials, chemical and biological sensors, bioimaging agents, and cancer therapy. Moreover, several unsolved issues related to metallacycle/metallacage‐cored fluorescent supramolecular assemblies are discussed in the context of possible future applications of this field.