Structures, luminescent properties and magnetic refrigeration of two series of Ln2III compounds.

Two Gd 2 compounds exhibit magnetic refrigeration properties with −Δ S m = 18.59 J kg−1 K−1 for 2 (Δ H = 7 T and T = 2.0 K) and −Δ S m = 18.75 J kg−1 K−1 for 4 (Δ H = 7 T and T = 2.0 K). Two series of LnIII 2 compounds, [Ln 2 (L1) 2 (tmhd) 2 (CH 3 O) 2 ] (Ln = Eu (1), Gd (2), Tb (3)) and [Ln 2 (dbm) 5 L2](Ln = Gd (4), Tb (5), Ho (6)), based on two Schiff base ligands have been synthesized and structurally and magnetically characterized. The structural analysis indicate that these compounds are μ 2 -O bridged dinuclear complexes and each center Ln(III) ion of them is eight-coordinated with a biaugmented trigonal prism geometries. Magnetic properties measurement exhibit that the two Gd 2 compounds 2 and 4 display magnetic refrigeration with −Δ S m = 18.59 J kg−1 K−1 for 2 (Δ H = 7 T and T = 2.0 K) and −Δ S m = 18.75 J kg−1 K−1 for 4 (Δ H = 7 T and T = 2.0 K). Moreover, complexes 1 , 3 and 5 show the characteristic lanthanum luminescence at room temperature. [ABSTRACT FROM AUTHOR]