Electrochemical properties and ESR characterization of mixed valence alpha-(XMo3-xVxW9O40)n- heteropolyanions with X = P and SiIV, x = 1, 2, or 3

The redox parameters of the Keggin anions alpha-(SiMo3-xVxW9O40)(4+x)- and alpha-(PMo3-xVxW9O40)(3+x)-, with X = 1, 2, or 3, are presented. The one-electron-reduced species were prepared by electrolysis and characterized by ESR spectroscopy both in solution and solid state. The results showed that the ESO spectra of the V4+ ion is dependent on the surrounding atoms, Mo(V)I, W(VI) and V(V). The electron hopping and delocalization characteristics of di and trivanadium compounds were also determined.