Magnetocaloric Effect and Slow Magnetic Relaxation on Two-Dimensional Layered 3d-4f Cluster-Based Metal–Organic Frameworks
Jia-Jia Yin, Tianqi Lu, Cheng Chen, Gui‐Lin Zhuang, Jun Zheng, Xiu‐Ying Zheng, Feng Shao
Abstract
Two novel two-dimensional layered 3d-4f cluster-based metal–organic frameworks with formulas {[Ln4Cr4(L)6(μ3-OH)4(μ4-O)4(H2O)5]·x(H2O)}n (Ln = Gd and x = 3 for 1; Ln = Dy and x = 5 for 2; H2L = thiodiglycolic acid) were synthesized by a building block strategy and characterized. Structural analysis showed that employing an octa-core metal cluster [Ln4Cr4] as the secondary building unit and flexible organic ligand thiodiglycolic acid as the linker formed compounds 1–2. The studies of magnetic properties showed that compound 1 had a large magnetic entropy change of 28.8 J kg–1 K–1 at 3.5 K, 7 T, and compound 2 displayed interesting single-molecule magnet behavior under a zero dc magnetic field with Ueff/kB = 12.3 K and τ0 = 1.6 × 10–5 s. In addition, the results of magnetic calculation for 1 suggested that a weak magnetic coupling interaction was presented in Gd···Gd and Cr···Cr, while the Gd···Cr exhibited a dominant antiferromagnetic coupling interaction. The weak magnetic coupling interaction between metal ions is beneficial to the enhancement of a magnetocaloric effect.