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

Abstract Two series of Ln III 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.