Single‐Molecule Magnetic Behavior in a Calix[8]arene‐Capped Heterometallic {Dy^III₄Co^II₄} Square‐Antiprismatic Cluster

Two isostructural octanuclear {(Ln III 4 Co II 4 )(C8A) 2 } compounds (Ln = Dy, Er; H 8 C8A = p‐tert ‐butylcalix[8]arene) are synthesized under solvothermal conditions for magnetic study. For comparison, an yttrium compound, having a similar structure, except for some coordinated DEF molecules replaced by water molecules, is obtained. These three compounds are featured with a sandwich‐like motif in which the heterometallic {Ln III 4 Co 4 II } square‐antiprismatic cluster is sandwiched between two calix[8]arene molecules in double‐cone conformation. Magnetic measurements reveal that the {Dy III 4 Co II 4 } compound exhibits single‐molecule magnetic behavior.