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Two new tetranuclear gadolinium clusters, [Gd4(μ3-OH)2(L1)6(beac)4] (1) and [Gd4(μ3-OH)2(L2)6(tmhd)4] (2) (HL1 = 5-(3-chlorobenzylidene)-8-hydroxylquinoline, HL2 = 5-(2-thenylidene)-8-hydroxylquinoline, beac = 1-benzoylaceton, tmhd = 2,2,6,6-tetramethyl-3,5-heptanedione), have been synthesized, then structurally and magnetically characterized. The X-ray structural analysis showed that both clusters 1 and 2 contain one Gd4 center with a rhombus-shaped arrangement, and all of the Gd(III) ions are located in a distorted square-antiprismatic coordination sphere. Magnetic property measurements indicate that 1 and 2 show magnetic refrigeration with −ΔSm = 20.43 J kg−1 K−1 for ΔH = 7 T at 2.0 K for 1 and −ΔSm = 19.94 J kg−1 K−1 for ΔH = 7 T at 2.5 K for 2.

Three new phenoxo-O-bridged dinuclear lanthanide(III) compounds, [Dy(bfa)2L1]2 (1), [Gd(hfac)3L2]2·C6H14 (2) and [Tb(hfac)3L2]2 (3) (bfa = benzoyltrifluoroacetone, hfac = hexafluoroacetylacetonate, HL1 = 2-[(3,4-dimethylaniline)-imino]methyl]−8-hydroxyquinoline and HL2 = 5-(2-thenylidene)-8-hydroxylquinoline), have been synthesized, then structurally and magnetically characterized. The X-ray structural analysis shows that 1–3 are phenoxo-O-bridged dinuclear compounds and the central eight-coordinated Ln(III) ions are in a slightly distorted dodecahedral geometry. Magnetic measurements indicated that slow magnetic relaxation behaviors were observed in 1 with an energy barrier (ΔE/kB) of 52.21 K and τ0 = 1.75 × 10−7 s; compound 2, however, exhibited magnetic refrigeration with −ΔSm = 15.06 J kg−1 K−1 for ΔH = 7.0 T at 2.0 K.

A series of lanthanide based dinuclear compounds, namely, [Ln(bfa)2L]2 (Ln = Gd (1), Tb (2), and Dy (3), bfa = benzoyltrifluoroacetone and HL = 2-[5-methyl-1,2-oxazol-imino]methyl]-8-hydroxyquinoline), were synthesized by employing a multidentate 8-hydroxyquinoline Schiff base derivative ligands (HL) and a bidentate β-diketonate coligand (bfa). The elemental analysis (EA), powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), single-crystal X-ray diffraction and magnetic properties of the three Ln2 compounds were completely characterized. Structures of 1–3 are similar to each other with a parallelogram Ln2O2 core. Magnetic properties study indicates that 1 exhibits antiferromagnetic exchange interaction between two nearby GdIII centers and shows magnetic refrigeration (−ΔSm = 17.78 J kg−1 K−1 for ΔH = 7 T at 2.0 K). Ac magnetic susceptibility measurements of 3 demonstrate that slow relaxation behavior is observed in 3, with effective energy barrier Ueff = 24.3 K and pre-exponential factor τ0 = 1.71 × 10−6 s.