Synthesis, structures and magnetic properties of cyano-bridged 3d-4f rectangular tetranuclear [Fe2IIILn2III] (Ln = Y, Tb, Dy) compounds containing [FeIII(bpy)(CN)4]- unit

Three cyano-bridged 3d-4f bimetallic rectangular tetranuclear compounds, [Fe-III(bpy)(CN)(2)(mu-CN)(2)](2) [Ln(III)(NO3)(2)(H2O)(3)](2)center dot 2H(2)O center dot 2CH(3)CN (Ln = Y (1), Th (2), Dy (3); bpy = 2,2'-bipyridine), have been prepared by diffusion and characterized by single crystal X-ray diffraction, IR spectra, elemental analysis and magnetic measurement. Single-crystal structural analysis shows that 1-3 are isomorphous and made of a neutral tetranuclear unit [Fe(2)(III)Ln(2)(III)] with two free water and two acetonitrile molecules. Furthermore, the tetranuclear unit [Fe(2)(III)Ln(2)(III)] is connected into supermolecular three-dimensional framework through hydrogen bonds. Magnetic susceptibility measurements for compounds 1-3 were performed on poly-crystalline samples. For compounds 2 and 3, there is weak ferromagnetic interaction between Fe(III) and Ln(III) ions. (C) 2013 Elsevier Ltd. All rights reserved.