Three Ln2 compounds (Gd2, Tb2 and Dy2) with a Ln2O2 center showing magnetic refrigeration property and single-molecular magnet behavior

Three dinuclear Ln 2 compounds, [Ln 2 (dbm) 4 (L - ) 2 ]·4CH 3 CN (Ln = Gd ( 1 ), Tb ( 2 ), Dy ( 3 ), HL = (E)-N'-(2-hydroxybenzylidene)benzohydrazide and dbm = dibenzoylmethane), have been obtained by a solvent evaporation method. The structural analyses indicate that the three Ln 2 compounds (Gd 2 , Tb 2 and Dy 2 ) are isostructural with a Ln 2 O 2 center. Magnetic investigations show the presence of magnetic refrigeration in the Gd-based compound with a -ΔS m value of 17.62 J kg −1 K −1 ( T  = 2.0 K and Δ H  = 7.0 T); for compound 3 , however, single-molecular magnet behavior (SMM) was observed ( U eff /k B  = 0.84 K and τ 0  = 1.08 × 10 −5 s).