New 3d-4f heterometallic clusters built from mixed glycine and iminodiacetate acid: dioctahedron {La2Ni9} and onion-like {Gd-5}subset of{Ni-12} with interesting magnetocaloric effect

The preparation, structures and properties of 3d-4f compounds, undecanuclear [La2Ni9(Gly)(12)(IDA)(3)(mu(3)-OH)(3)][La(H2O)(9)][Na-3(H2O)(7)(ClO4)(3)](ClO4)(6)center dot 5H(2)O (1) and isostructural heptadecanuclear [Ln(5)Ni(12)(Gly)(12)(IDA)(6)(mu(3)-OH)(9)(H2O)(3)](ClO4)(6)center dot 11H(2)O (Ln = Gd (2); Nd (3); Sm (4); Tb (5); Dy (6); Y (7)) based on mixed glycine (HGly) and iminodiacetate acid (H(2)IDA) ligands were described. The structure of the [La2Ni9(mu(3)-OH)(3)(IDA)(3)(Gly)(12)](3+) cationic cluster in 1 can be described as a face-shared and La-centered dioctahedron. However, the [Ln(5)Ni(12)(Gly)(12)(IDA)(6)(mu(3)-OH)(9)(H2O)(3)](6+) cationic clusters in 2-7 bear an onion-like {Ln(5)}subset of{Ni-12} structure, where the trigonal bipyramid {Ln(5)} core is encapsulated by the outer triangular orthobicupola {Ni-12} shell. Magnetic studies have been performed for these compounds, and 2 displays dominant ferromagnetic coupling and has a large magnetocaloric effect (21.8 J kg(-1) K-1, Delta H = 7 T).