Structure and magnetic properties of a 3d-4f Co^III ₂Dy^III₄ cluster

Structural determination and magnetic studies of a 3d-4f heterometallic hexanuclear [Co^III₂Dy^III₄(μ ₃-OH)₂(salpa)₄(NO₃) ₄(OAc)₄(H₂O)₂] (1) cluster, where H₂salpa = N-(2-hydroxybenzyl)-3-amino-1-propanol, are reported. Single-crystal X-ray diffraction studies reveal that the cluster contains a defect-dicubane central core composed of four Dy^III ions, which are supported by two oxygen atoms from the acetate groups, two alkoxo groups and two μ₃-OH groups, which are displaced above and below the Dy ₄ plane. Moreover, the remaining Co^III ions are linked to the defect-dicubane core through two alkoxo groups and two phenoxido groups. Because of the presence of diamagnetic Co^III ions, the magnetic properties of complex 1 can be attributed to the presence of the four Dy ^III ions. Variable temperature direct current (dc) magnetic susceptibility measurements reveal spin-orbital coupling and/or antiferromagnetic interactions between the Dy^III ions. Alternating current (ac) magnetic susceptibility measurements indicate that complex 1 exhibits slow magnetization relaxations.