Coordination polymers of lanthanide elements and metatungstate: Syntheses, structure and magnetic property

Four new organic–inorganic hybrid compounds based on lanthanide elements and metatungstate, (NH4)4[Er2(pydc)2(H2O)9(H2W12O40)]·12H2O (1); (NH4)3[Ln3(pydc)3(H2O)15(H2W12O40)]·nH2O, Tm (2), n = 17; Yb (3), n = 20; Lu (4), n = 13; pydc = pyridine-3,5-dicarboxylate were conventionally synthesized and characterized by element analysis, IR spectrometry, thermogravimetric analysis and single-crystal X-ray diffraction. Compound 1 shows a two-dimensional structure with (72·3)(72·3)(75·112·3) topology, and compounds 2–4 are isomorphic and have a three-dimensional (3D) framework with α-polonium structure if the [Ln3(H2W12O40)]3+ is considered as six-connected nodes and pydc as linker. The formation of these compounds with two types of multidimensional structures mainly depends on size of Ln and then on coordination modes of the ligands. Furthermore, magnetic properties of 1–3 have been examined. To our best knowledge, compounds 2–4 represent the first examples of 3D inorganic-organicarchitectures based on lanthanide, polyoxometalate and pyridine-3,5-carboxylic acid.