Magnetic refrigeration property and slow magnetic relaxation behavior of five dinuclear Ln(III)-based compounds

Abstract

In this work, a series of dinuclear Ln(III)-based compounds with the molecular form [Ln2(L)2(dbm)2(H2O)2]·nCH3OH (Ln(III) = Eu (1), Gd (2), Tb (3), Dy (4) and Ho (5), Hdbm = 1,3-diphenyl-1,3-propanedione and H2L = 2-[(1E)-{[(pyridin-2-yl)formamido]imino}methyl]benzoic acid) have been successfully synthesized using a polydentate Schiff base ligand (H2L) and reacting it with the β-diketone salts Ln(dbm)3·2H2O. The crystal structures and magnetic properties of the five Ln2 compounds have been completely studied. The crystal structure studies reveal that compounds 1–5 are isostructural and show a dinuclear structure with a parallelogram Ln2O2 core. The magnetic research suggests that the Gd2 compound shows a cryogenic magnetic refrigeration property with magnetic entropy (−ΔSm) = 23.2 J K−1 kg−1 (T = 2.0 K and ΔH = 7.0 T), while the Dy2 compound exhibits slow magnetic relaxation behavior.