Crystal Structures and Magnetic Refrigeration Properties of Two Gd2 Complexes

By utilizing a polydentate Schiff base ligand (H2L=pyridine-2-carboxylic acid (3,5-di-tert-butyl-2-hydroxy-benzylidene) -hydrazide), reacting with Gd(dbm)(3)center dot 2H(2)O (Hdbm=dibenzoylmethane) and Gd(NO)(3)center dot 6H(2)O, respectively; two new Gd-2 complexes formulated as [Gd-2(L)(2)(dbm)(2)(C2H5OH)(2)] (1) and [Gd-2(L)(2)(HL)(2)(DMF)]center dot 2CH(3)CN (2) (DMF=N, N-dimethylformamide) have been obtained by using solvothermal method. The crystal structures and magnetic properties of the two Gd-2 complexes have been systematically studied. The crystal structures study reveals that each eightcoordinate Gd3+ ion in 1 possesses a distorted triangular dodecahedron; the two central Gd(III) ions are connected by two mu(2)-O, resulting in a rhombic-shaped Gd2O2 core. However, for 2, each central Gd(III) ion is nine-coordinate and their coordination configurations can be described as distorted spherical capped square antiprism, and the two central Gd.. ions are connected by three mu(2)-O forming a triangular biconical-shaped Gd2O3 core. Magnetic investigations showed that the two Gd-2 complexes displayed magnetic refrigeration properties with the magnetic entropy (-Delta S-m) of 20.16 J.K-1.kg(-1) for 1 and 17.14 J.K-1.kg(-1) for 2 at Delta H=70 kOe and T=2.0 K. CCDC: 2111657, 1; 2111658, 2.