Two Ln4 clusters based complexes exhibiting magnetocaloric effect and magnetic dynamics behaviors.

Two new tetranuclear Ln-based clusters, namely [Ln 4 ( μ 3 -OH) 2 L 6 (beac) 4 ] (Ln = Gd ( 1 ) and Dy ( 2 )), were successfully assembled by employing 5-(2-thenylidene)-8-hydroxylquinoline (HL) and 1-benzoylacetone (Hbeac). They were structurally characterized by single crystal X-ray diffraction. In 1 ·Gd and 2 ·Dy, the structures of them are very similar with planar [Ln 4 O 2 ] cluster at the center, four Ln(III) ions in which are further coordinated by six L − and four beac − anions in the modes of μ 2 -η 2 η 1 for L − and μ 2 -η 2 η 1 for beac − , respectively. Additionally, the magnetic measurement of them reveal that 1 ·Gd displays magnetic entropy change (−Δ S m ) of 21.55(3) J K −1  kg −1 at 2 K for Δ H  = 7 T. For 2 ·Dy, it exhibits slow magnetic relaxation behavior with the energy barrier (Δ E / k B ) of 27.96(7) K. [ABSTRACT FROM AUTHOR]