Synthesis and Characterization of a Heterometallic Extended Architecture Based on a Manganese(II)-Substituted Sandwich-Type Polyoxotungstate

The reaction of [α-P₂W15O56]12- with MnII and DyIII in an aqueous basic solution led to the isolation of an all inorganic heterometallic aggregate Na10(OH₂)42[{Dy(H₂O)₆}₂Mn₄P₄W30O112(H₂O)₂]·17H₂O (Dy₂Mn₄-P₂W15). Single-crystal X-ray diffraction revealed that Dy₂Mn₄-P₂W15 crystallizes in the triclinic system with space group P 1 ¯ , and consists of a tetranuclear manganese(II)-substituted sandwich-type phosphotungstate [Mn₄(H₂O)₂(P₂W15O56)₂]16- (Mn₄-P₂W15), Na, and DyIII cations. Compound Dy₂Mn₄-P₂W15 exhibits a 1D ladder-like chain structure based on sandwich-type segments and dysprosium cations as linkers, which are further connected into a three-dimensional open framework by sodium cations. The title compound was structurally and compositionally characterized in solid state by single-crystal XRD, powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric (TGA), and elemental analyses. Further, the absorption and emission electronic spectra in aqueous solutions of Dy₂Mn₄-P₂W15 and Mn₄-P₂W15 were studied. Also, magnetic properties were studied and compared with the magnetic behavior of [Mn₄(H₂O)₂(P₂W15O56)₂]16-.