Structures and magnetic properties of two series of phenoxo-O bridged Ln2 compounds: Two Gd2 compounds displaying magnetic refrigeration properties

Two series of lanthanide dinuclear compounds, namely[Ln(hfac)(2)L](2) (Ln(III) = Gd (1), Ho (2) and Er (3), hfac = hexafluoroacetylacetonate, HL = 2-[[(4-iodophenyl)imino]methyl]-8-hydroxyquinoline) and [Ln(tfac)(2)L](2) (Ln(III) = Gd (4) and Tm (5), tfac = trifluoroacetylacetonate), have been synthesized and characterized by elemental analysis, IR, PXRD, UV-Vis and single crystal X-ray diffraction. Single-crystal X-ray diffraction analysis shows that the two series of Ln(2) compounds have very similar structures and each eight-coordinated center Ln(III) ion is in a slightly distorted dodecahedral geometry with two bidentate beta-diketonate coligands and two mu(2)-O bridging 8-hydroxyquinoline Schiff base ligands. The magnetic study reveals that 1 and 4 display cryogenic magnetic refrigeration properties with maximum -Delta S-m values of 16.41 and 18.32 J K-1 kg(-1) at 2.0 K and 7.0 T, respectively. (C) 2017 Elsevier B.V. All rights reserved.