The synthesis of dynamic chiral lanthanide complex emitters has always been difficult. Herein, we report three pairs of dynamic chiral Eu^III complex emitters (R/S-Eu-R-1, R = Et/Me; R/S-Eu-Et-2) with aggregation-induced emission. In the molecular state, these Eu^III complexes have almost no obvious emission, while in the aggregate state, they greatly enhance the Eu^III emission through restriction of intramolecular rotation and restriction of intramolecular vibration. The asymmetry factor and the circularly polarized luminescence brightness are as high as 0.64 (⁵D₀ → ⁷F₁) and 2429 M⁻¹cm⁻¹ of R-Eu-Et-1, achieving a rare double improvement. R-Eu-Et-1/2 exhibit excellent sensing properties for low concentrations of Cu^II ions, and their detection limits are as low as 2.55 and 4.44 nM, respectively. Dynamic Eu^III complexes are constructed by using chiral ligands with rotor structures or vibration units, an approach that opens a door for the construction of dynamic chiral luminescent materials.

Although great progress has been made in the design, synthesis, and performance expansion of porous materials, new porous materials with stable structures still need to be explored further. In recent years, porous molecular crystals formed by intermolecular interactions have attracted wide attention from chemists, especially metal hydrogen-bonded organic frameworks (M-HOFs) formed by connecting metal complexes through hydrogen bonds. Metal complexes with specific properties (e.g., magnetism, luminescence, sensing, and catalysis) can expand and develop the application of M-HOFs further. However, the huge volume, irregular shape, complex coordination modes, and interference of coordination bonds pose certain challenges in the synthesis and performance expansion of M-HOFs. In this frontier, we summarize the latest progress in the use of 3d, 4d, and 4f metal complexes for the synthesis of M-HOFs, and briefly introduce the performance expansion of these M-HOFs, which is expected to help expand new porous materials with stable structures and specific functions.

A Dy₃ complex with the highest energy barrier of all reported triangular-shaped Ln₃ single-molecule toroics.

The discovery of hydrogen-bonded organic frameworks (HOFs) has offered new opportunities for the expansion of porous materials. The field of HOFs has also introduced a new challenge—the design and synthesis of lanthanide HOFs (Ln–HOFs). Given that Ln complexes have various coordination modes, complex coordination structures, and irregular shapes, Ln–HOFs are extremely difficult to construct. In this study, a series of dysprosium-based HOFs (Dy–HOFs), namely, [Dy(L¹)₃(CH₃OH)·Phen]_n (Cl-1) and [Dy(L²)₃(CH₃OH)·Phen]_n (Br-1), were designed and synthesized for the first time under solvothermal conditions of 5,7-dichloro/dibromo-2-methyl-8-quinolinol (L¹/L²), Dy(NO₃)₃·6H₂O, and 2,9-dimethyl-1,10-phenanthroline (Phen). The porous Cl-1 (Br-1) was filled with Phen molecules linked by various supramolecular weak interactions. After Cl-1 (Br-1) was incubated at 260 °C for 2 h under a N₂ atmosphere, we found that only free Phen in the pores disappeared and Cl-2 (Br-2) was obtained. Magnetic characterization studies revealed that Cl-1 and Br-1 exhibited inconspicuous slow relaxation behavior. Unexpectedly, Cl-2 and Br-2 exhibited an evident single-ion magnetic (SIM) behavior, and their energy barriers were 97 and 87 K, respectively. We achieved the off → on SIM conversion of the Dy–HOFs for the first time.

A {Gd₁₈} nanowheel was solvothermally synthesized. It features a rare single-stranded skeleton that looks like a Reuleaux triangle with vertices buckled in, represents the highest nuclearity and the largest size in any pure Ln wheels reported, and shows a large MCE.