A Cubic Tinkertoy-like Heterometallic Cluster with a Record Magnetocaloric Effect

Clusters showing a giant magnetocaloric effect (MCE) are of interest as molecular coolants for magnetic refrigeration. Herein, we report two heterometallic clusters, denoted as GdNi@Cl and SmNi, just to highlight their inorganic core motifs, obtained by ligand-controlled co-hydrolysis of Ni²⁺ and Ln³⁺ (Ln = Gd, Sm) in the presence of N-(2-hydroxyethyl)iminodiacetic acid (H₂HEIDA). Both clusters display fascinating cubic Tinkertoy-like structures, with the core motifs being built of multiple metallic shells of Platonic and Archimedean polyhedra. The isothermal magnetic entropy change─a direct measurement of MCE─was determined to be 52.65 J·kg^-1·K^-1 at 2.5 K and 7.0 T for the Gd-containing cluster; this value is the highest known for any molecular clusters so far reported.