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