Isolation, structure and magnetic properties of two novel core-shell 3d-4f heterometallic nanoscale clusters

Two novel core-shell Ni-Ln nanosized clusters, Na₄(H₃O)₄[Nd₃₈Ni_42.5(IDA)₄₂(OAc)₄(CH₃CH₂OH)₂(CO₃)₁₈(μ₃-OH)₆₂(μ₃-O)₆(H₂O)₁₂]Cl₆·26H₂O (1) and Na[Pr₄₂Ni₃₈(μ₃-OH)₇₁(μ₃-O)₄(IDA)₃₈(NH₂CH₂COO)₂(OAc)₂(CH₃CH₂OH)₂(CO₃)₁₆(H₂O)₆Cl₇]Cl₃·37H₂O (2) (IDA = iminodiacetate), were successfully prepared using the Cl⁻ anion and the flexible ligand iminodiacetic acid. Structural analysis indicates that the discrete dumbbell-shaped 3d-4f heterometallic cluster in 1 is constructed from two {Nd₁₉Ni₂₁} clusters connected by one {NiO₆} unit, whereas the bowknot-shaped nanosized cluster is composed of two {Pr₁₉Ni₁₉} clusters ligated by two {Pr₂} units and CO₃²⁻ anions. The formation of both compounds indicates that Cl⁻ ions play important roles and act not only as balance anions but also as template and bridging ligands. The magnetic properties of compounds 1 and 2 were investigated, and it was revealed that they display dominant antiferromagnetic exchange.