Synthesis and catalysis of a Co13 disk surrounded by vanadium–oxygen crown

Abstract

By the reaction of the binuclear cobalt-containing polyoxovanadate [Co₂(H₂O)₂V₁₀O₃₀]⁶⁻ with methanol, a tridecanuclear cobalt containing polyoxovanadate, [Co₁₃(OH)₆(OCH₃)₆V₂₄O₇₂]¹⁰⁻ (Co13), was synthesized. Single crystals suitable for X-ray crystallographic analysis were obtained as trimethylphenylammonium salts. The tridecanuclear cobalt core exhibited a planar disk structure and 24 vertex-sharing VO₄ units surrounded the edge of the disk. This is the largest VO₄-based polyoxovanadate as far as we know. Compound Co13 was stable in the solution state. Electrochemical analysis showed the possibility of Co13 to act as an oxidation catalyst for alcohols. Compound Co13 acted as a catalyst for oxidation of several alcohols. After the reaction, the Co13 catalyst was retrieved by the addition of an excess amount of ethyl acetate and filtration. The structure of the catalyst was maintained and reused. The oxidation of not only aromatic but also aliphatic alcohols proceeded with Co13. Compound Co13 showed catalytic performance for the oxidation of secondary alcohols even in the presence of alkenic and primary alcoholic functions.