Wheel-like Gd42 polynuclear complexes with significant magnetocaloric effect

Abstract

Two novel wheel-like lanthanide nanoclusters with 42 nuclearity [Ln₄₂L₁₄(OH)₂₈(OAc)₈₄] (abbreviated as Ln₄₂; Ln = 1-Gd, 2-Dy; HL = 3-methoxysalicylaldehyde O-vanillin) were structurally and magnetically characterized. The Ln₄₂ 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 °C. Strikingly, the Gd₄₂ 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 −ΔS_m^max = 42.60 J kg⁻¹ K⁻¹.