Wheel-like Gd-42 polynuclear complexes with significant magnetocaloric effect

Two novel wheel-like lanthanide nanoclusters with 42 nuclearity [Ln(42)L(44)(OH)(28)(OAc)(84)] (abbreviated as Ln(42); Ln = 1-Gd, 2-Dy; HL = 3-methoxysalicylaldehyde O-vanillin) were structurally and magnetically characterized. The Ln(42) species were constructed from O-vanillin and lanthanide acetate, in which a big cylindrical cavity formed with the external and internal diameters of the wheels in the clusters being about 3.6 nm and 1.5 nm, respectively. Both 1-Gd and 2-Dy exhibit high thermal stability and decompose above 320 degrees C. Strikingly, the Gd-42 congener displayed significant magnetic refrigeration, the high isotropy Gd nuclearity and weak ferromagnetic interaction between adjacent Gd3+ ions lead to a large magnetocaloric effect (MCE) with -Delta S-m(max) = 42.60 J kg(-1) K-1.