Four 3d–4f heterometallic Ln45M7 clusters protected by mixed ligands

Abstract

Four high-nuclearity lanthanide–transition metal clusters, formulated as [Ln₄₅M₇(OH)₆₈(CO₃)₁₂(CH₃COO)₂₆(CH₃CH₂COO)₆(H₂O)₇₀]·(ClO₄)₂₅·(H₂O)_x (abbreviated as Ln₄₅M₇: 1, Gd₄₅Co₇; 2, Gd₄₅Ni₇; 3, Dy₄₅Co₇; 4, Dy₄₅Ni₇; x ≈ 50), were obtained with the mixed protecting ligands acetate and propionate. Structural analysis shows that the cluster cationic core contains 52 metal ions featuring a bowl-like structure. 12 CO₃²⁻ and 3 ClO₄⁻ anions play the role of mixed anion templates. Magnetic studies reveal that the two isotropic Gd-containing clusters Gd₄₅Co₇ and Gd₄₅Ni₇ exhibit a large magnetocaloric effect (MCE), while the anisotropic Dy-containing clusters Dy₄₅Co₇ and Dy₄₅Ni₇ show slow relaxation of magnetization.