The self-assembly of the high-nuclearity Ln-exclusive nanoclusters is challenging but of significance due to its aesthetically pleasing architectures and far-reaching latent applications in magnetic cooling technologies. Herein, two novel high-nuclearity lanthanide nanoclusters were successfully synthesized under solvothermal conditions, formulated as {[Gd18(IN)20(HCOO)8(μ6-O)(μ3-OH)24(H2O)4]·4H2O} n and {[Eu18(IN)16(HCOO)8(CH3COO)4(μ6-O)(μ3-OH)24(H2O)4]·5H2O} n (abbreviated as Gd18 and Eu18 , HIN = isonicotinic acid). Both of them possess novel and exquisite windmill-shaped cationic cores in the family of high-nuclearity Ln-exclusive nanoclusters. Remarkably, the adjacent second building units are interconnected into a three-dimensional (3D) metal–organic framework by IN– ligands. As expected, the abundant existence of GdIII ions endows Gd18 with a favorable magnetic entropy change at 2.0 K for ΔH = 7.0 T (−ΔS m max = 40.0 J kg–1 K–1), and Eu18 displays the typical luminescence of EuIII ions.

Assembling and studying high-nuclearity 3d-4f metal clusters represent a pregnant and challenging research hotspot. Based on anionic template and ligand-controlled hydrolytic methods, two heterometallic metal clusters, formulated as [Gd23Ni20(DTA)20(CO3)4(CH3COO)6­(SiO4)4(CH3CH2OH)2(μ3-OH)33(μ2-OH)4(H2O)16]·Cl2·30H2O and [Eu23Ni20(DTA)20(CO3)4(CH3COO)6­(SiO4)4(CH3CH2OH)2(μ3-OH)33(μ2-OH)4(H2O)16]·Cl2·46H2O (abbreviated as Gd 23 Ni 20 , Eu 23 Ni 20 , H2DTA = thiodiglycolic acid), are successfully obtained, which both feature similar double-shell-shaped structures with a Ni 20 building unit encapsulating a Ln 23 aggregation. The structural analysis illustrates that the SiO4 4– anion, serving as the anionic template in this work, is reported for the second time in 3d-4f metal clusters. In terms of the magnetic properties, large amounts of Gd3+ and Ni2+ ions contribute to the MCE of compound Gd 23 Ni 20 , along with 38.15 J kg–1 K–1 at ΔH = 7.0 T for 2.0 K. It is worth mentioning that compound Gd 23 Ni 20 exhibits an excellent magnetic entropy change at low fields (−ΔS m = 19.10 J kg–1 K–1 at 2.0 K for ΔH = 2.0 T). In addition, Gd 23 Ni 20 exhibits preferable solvent and thermal stability.