A high-nuclearity 3d–4f cluster of [Gd30CoII 6CoIII 6(OH)56(NO3)12(CH3COO)30(H2O)30]·(NO3)22·(en)3·(H2O)3 (1) was synthesized through the reaction of Gd­(NO3)3·6H2O, Co­(NO3)2·6H2O, and sodium acetate in a mixture of ethanediamine (en), ethanol, and deionized water. The cluster core in 1 features a double-shell structure with a Co12 icosahedron encapsulating a Gd30 icosidodecahedron. A magnetic study reveals that separating Co2+ ions with Gd3+ ions can effectively reduce the magnetic interaction of 3d–4f clusters. Significantly, the magnetocaloric effect (MCE) of 1 at 2 K and 7 T is up to 44.7 J kg–1 K–1, the largest MCE reported to date in the 3d–4f metal clusters.

Two unique polyoxometalate (POM)-encapsulated tubular materials with the formula K­(H2O)6[M6(btp)6(H2O)22]­(P2W18O62)3(Hbtp)5(btp)3·52H2O [M = Mn (1) and Co (2); btp = 2,6-bis­(1,2,4-triazol-1-yl)­pyridine] were designed and synthesized based on the Dawson POM and V-type btp ligand, as confirmed by IR, X-ray diffraction (XRD), and element analysis. Single-crystal XRD analyses of compound 1 show that two kinds of remarkable metal–organic supramolecular nanotubes, including trigonal and hexagonal nanotubes, are constructed along the c-axis direction via π···π-packing interactions between {Mn3(btp)3} rings and the btp ligands, of which [α-P2W18O62]6– anions are confined in channels, making the entire structure extraordinarily stable. Meanwhile, the coordinated [α-P2W18O62]6– anion within the hexagonal channel makes the channel highly hydrophilic and attracts a number of guest water molecules to fill in the free space, conducive to proton transport. Therefore, the single-crystal sample of 1 exhibits a high proton conductivity of 6.39 × 10–3 S cm–1 along one-dimensional channels, 30 times higher than that of a pellet sample at 358 K and 98% relative humidity.

A novel bilayer metal-organic framework is assembled with a perfect intralayer triangular subnet and ideal interlayer Td arrangement between unprecedented crown-like Co7 cluster units, exhibiting high spin frustration.

OH) 14 (CO 3 ) 9 (CH 3 CH 2 COO) 6 (deaand Dy (2)) have been obtained by reacting CoCl 2 •6H 2 O, Ln(NO 3 ) 3 •6H 2 O, and a mixture of ligands consisting of propionate and diethanolamine (H 2 dea). Crystal structural analysis exhibits two three-blade propellers composed of the Co III 3 Ln 9 units connected by one Co II ion and three CO 3 2− ions, which assemble into a double-propeller-like structure (Ln 18 Co II Co III 6 ). Magnetocaloric effect (MCE) studies indicate that Gd 18 Co 7 exhibits a large entropy change (−ΔS m ) of 36.9 J kg −1 K −1 .