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[Nd38Ni42.5(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.