High-Nuclearity 3d–4f Clusters as Enhanced Magnetic Coolers and Molecular Magnets

Four 52-metal-ion 3d–4f cluster complexes featuring a common core of Ln42M10 (Ln = Gd3+, Dy3+; M = Co2+/3+, Ni2+) were obtained through self-assembly of the metal ions templated by mixed anions (ClO4 – and CO3 2–). Magnetic studies revealed that the Gd42Co10 and Gd42Ni10 clusters exhibit the largest magnetocaloric effect (MCE) among any known 3d–4f complexes. Replacement of Gd3+ ions with anisotropic Dy3+ ions caused significant changes in the magnetic behavior of the clusters; both Dy42Co10 and Dy42Ni10 displayed slow relaxation of the magnetization.