Vanadium(IV)-substituted tungstoantimonate [Sb_2W_(20)(VO)_2(H_2O)_4O_(70)]~(10-): synthesis, crystal structure and electrochemistry

摘要

A vanadium(IV)-substituted tungstoantimonate, K_8Na_2[Sb_2W_(20)(VO)_2(H_2O)_O_(70)] centre dot 18.5H_2O (1), has been synthesized in aqueous solution and characterized by IR, UV-Vis, elemental analysis, TG and X-ray single-crystal diffraction analysis. The structure of 1 was composed of two V(IV) ions linked to a [Sb_2W_(20)O_(70)]~(14-) fragment via V-O(W) bonds; the anions are connected by K~+ to construct a two-dimensional network complex. The electrochemical behavior of 1 was investigated in buffer solution (pH 2.5) by cyclic voltammetry. In the potential range between -0.7 and 0.9 V, the compound exhibits successive redox processes of the addenda atoms (W) in a negative potential range, and also redox originating from the substituted atom (V) at a more positive potential. Compound 1 has good electrocatalytic activity towards the reduction of iodate.