SYNTHESIS AND CHARACTERIZATION OF NEW KEGGIN-BASED STRUCTURE TUNGSTOCOBALTATES - K-9CO3+W11O39 AND ITS VANADIUM DERIVATIVES, K-8CO2+W11V4+O40, K-7CO2+W11V5+O40, AND K-6CO3+W11V5+O40

摘要

Good yield synthesis of the potassium salts of four new interrelated polyoxometalates, Co3+W11O39(9-) (I), Co2+W11V4+O40(8-) (II), Co2+W11V5+O40(7-) (III), and Co3+W11V5+O40(6-) (IV), are reported. The title compounds have been characterized by IR and UV-Vis.-NIR spectroscopies, cyclic voltammetry and magnetic measurements. IR spectra confirm that I has the lacunary structure of an undecatungstate anion, while II through IV have a substituted alpha-keggin structure with the vanadium atom located at an octahedral site replacing one tungsten atom. Optical data confirm the oxidation states for both, the Co and V atoms, as formulated for I through IV. References: 14