Study on magnetic properties of two dysprosium(III)-substituted antimonotungstates with different substitution modes

•Two dysprosium(III)-substituted antimonotungstates were isolated by hydrothermal method.•The variable temperature magnetic susceptibility of the two similar compounds is different.•The magnetic source of the two compounds was analyzed by 2D COS-IR.•The coordination of dy results in the difference of variable temperature magnetic susceptibility.•The two compounds show probable single-molecule-magnet behavior. Two Polyoxometalates have been constructed by simple hydrothermal synthesis using rare-earth (RE) and antimonotungstates (ATs) {B-α-SbW9O33} as raw materials with the molecular formulas of H4.5Na1.5(H2O)6(C3H5N2)3{Na(Sb3O)2[B-β-SbW8O31Dy(H2O)2]3}·12H2O (1) and H9(C3H5N2)5{[Sb6IIISbVDy2WO10(H2O)5][(B-β-SbW9O33)2(B-α-SbW9O33)]}·16H2O (2). X-ray Single crystal diffractometer analysis shows that both 1 and 2 possess trimer configurations. Polyoxoanion 1 is assembled from three trilacunary {B-β-SbW8O31Dy(H2O)2}p units linked via {Na(Sb3O)2} cluster, where the trilacunary {B-β-SbW8O31Dy(H2O)2} unit is formed by the tetralacunary {B-β-SbW8O31} unit captures one Dy(H2O)23+ cation. Polyoxoanion 2 is composed of a novel 5p−4f heterometallic cluster {Sb6IIISbVDy2WO12(H2O)5} simultaneously stabilized by two {B-β-SbW9O33} units and one {B-α-SbW9O33} unit. In addition, two-dimensional correlation infrared spectroscopy (2D COS-IR) under magnetic disturbance was measured to investigate the difference of the variable temperature magnetic susceptibility between two compounds to explore the source of magnetic properties, and further magnetic property tests indicate that 1 and 2 may exhibit single-molecule-magnet behavior with distinct frequency dependence. This work deepens the theory of 2D COS-IR and also enriches the theoretical and experimental data of magnetism. [Display omitted]