Synthesis, reactivity, x-ray structure and thermal study of the mixed-metal oxide hydrate [Mn(H2O)2V2O6]

The mixed-metal oxide hydrate Mr(H2O)2V2O6 (1) has been prepared by the reaction of potassium vanadate with manganese chloride tetrahydrate in aqueous reaction medium at 70 72 C. The orange-red crystals of (1) have been characterized by FT-IR, Raman, and UV-VIS spectroscopy, thermogravimetric analysis, magnetic susceptibility measurement, and complete single crystal x-ray structure analysis. The structure of (1) consists of the stacks of zigzag chains of comer sharing {VO4} tetrahedra cross-linked by {MnO4(H2O)2} octahedral units generating a complex Mn/O/V/O network. The structure exhibits cavities and tunnels delimited by four and six polyhedra. Thermal treatment of (1) under nitrogen atmosphere resuits into the removal coordinated water. The dehydrated samples of (1) exhibits reversible water absorption. Observed room temperature magnetic moment (5.87 BM) of (1) is consistent with the presence of high-spin Mn(ll) centers. Crystal data for (1): Orthorhombic space group Pnma (No. 62), a = 5.6085(6), b = 10.917(16), c = 12.042(2) A, V = 737.3(2) A3, Z = 4. The reactions of (1) with some simple ligands is described.