Assembly of tetra-nuclear lanthanide compounds: Structures, magnetic refrigeration and slow relaxation of magnetization.

[Display omitted] • Two tetra-nuclear lanthanide compounds were successfully prepared. • Antiferromagnetic interactions between adjacent Gd3+ ions were observed in 1. • 1 and 2 exhibit magnetic refrigeration and slow magnetic relaxation behaviors, respectively. Two novel tetranuclear lanthanide compounds with the formula [Ln 4 (L1) 2 (L2) 2 (μ 2 - OCH 3) 2 (CH 3 OH) 2 ]·CH 3 OH (Ln = Gd (1), Dy (2), H 2 L1 = 2-[(2-(hydroxyimino)propanehydrazide)methyl]-8-hydroxyquinoline, H 3 L2 = 2-[(2-(N'-acetylhydrazino)propanehydrazide)methyl]-8-hydroxyquinoline) were successfully prepared, and structurally and magnetically characterized. Crystal structural analyses reveal that two compounds are isostructural and they all consist of a tetranuclear Ln 4 cluster. All Ln(III) ions in them are eight-coordinated and located in a distorted triangular dodecahedron geometry. Magnetic studies indicate that 1 exhibits large magnetocaloric effect with the entropy change (-Δ S m) of 32.10 J Kg−1 K−1 (at T = 2.0 K and Δ H = 7 T), and 2 displays slow magnetic relaxation behaviors. [ABSTRACT FROM AUTHOR]