Four tetra-nuclear lanthanide complexes based on 8-hydroxyquinolin derivatives: magnetic refrigeration and single-molecule magnet behaviour†
Abstract
Four tetra-nuclear lanthanide complexes: {[Ln4(L)6(tmhd)4(μ3-OH)2]·mH2O} (Ln = Gd (1, m = 0), Tb (2, m = 3), Dy (3, m = 0), Ho (4, m = 0); L = 5-((pyridin-4-ylmethylene)amino)quinolin-8-ol, tmhd = 2,2,6,6-tetramethylheptane-3,5-dione) were fabricated and structurally characterized. Compounds 1–4 are isostructural and belong to the monoclinic system with space group P21/n. The cores of the complexes contain a tetranuclear arrangement of LnIII ions, which is bridged by the two pyramidal μ3-OH− ions, and the four LnIII ions are precisely coplanar. The magnetic study reveals that 1 exhibits cryogenic magnetic refrigeration property (−ΔSm = 20.85 J K−1 kg−1), whereas compound 3 exhibits slow relaxation of the magnetization.