Synthesis and Characterization of New Keggin-Based Structure Tungstocobaltates: K₉[Co³⁺W₁₁O₃₉] and its Vanadium Derivatives, K₈[Co²⁺W₁₁V⁴⁺O₄₀], K₇[Co²⁺W₁₁V⁵⁺O₄₀], and K₆[Co³⁺W₁₁V⁵⁺O₄₀]

Abstract

Abstract Good yield synthesis of the potassium salts of four new interrelated : olyoxometalates, [Co3+W11O39]9-(I), [Co2+W11V4+O4]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 α-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.