Supramolecular chemistry has made significant progress in the past several decades. Employing various noncovalent bonds, supramolecular self-assembly provides an efficient method for the miniaturization and intelligentization of functional devices. The 4f orbitals of lanthanide ions (Ln^III) endow Ln-based complexes with extraordinary optical, catalytic and magnetic properties.  

Compared with the well-explored mononuclear Ln-coordination complexes, polynuclear lanthanide assemblies offer more structural superiority and functional advantages. Despite the challenges brought by the peculiar coordination geometries of Ln^III ions, the development of polynuclear lanthanide supramolecules have made great progress in the fields including structuralevolution, chirality induction, optimization of the luminescent performances, up-conversion at the molecular scale, host-guest chemistry, catalysis, and magnetic materials in recent decades. 

The research group led by Prof. SUN Qingfu from Fujian Institute of Research on the Structure of Matter (FJIRSM) of the Chinese Academy of Sciences, reviewed the recent developments on polynuclear lanthanide supramolecular assemblies and their functional applications. This review paper was published in Chemical Reviews. 

The researchers first summarized the design principles in the construction of polynuclear lanthanide supramolecular assemblies. The assemblies were classified into helicates, tetrahedral and derivatives, cubes, other polyhedral structures, d-f heterometallic structures, chiral helicates and tetrahedral. Design principles concerning the water solubility and chirality of the lanthanide-organic assemblies that are vital in extending their applications were also emphasized. 

They then focus on the developments in luminescent and catalytic applications. The progress made in UV and visible light emission, near infrared light emission, circularly polarized light, two-photon absorption, up-conversion, host-guest chemistry, luminescent sensing was summarized. Several cases in which polynuclear lanthanide assemblies were used as catalysis and lanthanide separation extractants were also presented. 

Finally, the researchers reviewed the applications of the polynuclear lanthanide assemblies in single-molecular magnet, magnetic refrigerating materials, and magnetic resonance imaging. 

This study provides some universal structural design strategies to construct more elegant lanthanide-based structures and enhance their properties. It can serve as a reference for scientists seeking to design novel supramolecular materials exhibiting unusual optical, catalytic and magnetic properties.