General One-Step Self-Assembly of Isostructural Intermetallic Co^II₃Ln^III Cubane Aggregates

A new family of Co/rare-earth intermetallic cubane aggregates [Co₃Ln­(hmp)₄(OAc)₅H₂O] (Ln = Dy, Ho, Er, Tm, Yb, Y) have been synthesized by self-assembly. Single-crystal X-ray diffraction analysis revealed that they are remarkably isostructural in showing a common [Co₃Ln] core. Magnetic studies showed that the Dy, Er, Tm, Yb, and Y complexes are ferromagnetic. The Dy complex exhibits the largest magnetocaloric effect (−ΔS_m = 12.58 J kg^–1 K^–1), which can be attributed to the large magnetic density of Dy^III.