Two Series of Lanthanide Coordination Polymers with 2-Methylenesuccinate: Magnetic Refrigerant, Slow Magnetic Relaxation, and Luminescence Properties

Abstract

Two series of lanthanide coordination polymers based on 2-methylenesuccinate acid (H2MSA) ligand, {[Ln(MSA)(NO3)(H2O)2]·2H2O}n (Ln = Gd (1); Tb (2); Dy (3)) and {[Ln2(MSA)3(H2O)4]·3H2O}n (Ln = Gd (4); Tb (5); Dy (6)), have been synthesized. Compounds 1–3 exhibit a one-dimensional (1D) zigzag chain structure, in which the neighboring Gd3+ ions are connected by two carboxylate groups from different MSA2– ligands. Compounds 4–6 all consist of unique 1D lanthanide-carboxylate building units [Ln4(CO2)6]n constructed from the adjacent Ln3+ ions and carboxyl groups of the H2MSA ligands, which can further generate two-dimensional layer structures via the link of MSA2–. The magnetic study reveals that the weak ferromagnetic interactions between adjacent Gd3+ ions both exist in 1 and 4. Meanwhile, 1 and 4 display significant cryogenic magnetocaloric effects with maximum −ΔSm values of 38.86 and 39.31 J kg–1 K–1 at 2 K and 7 T, respectively, and 3 was found to exhibit slow relaxation of the magnetization. Solid stat...