Organicainorganic heteropoly blue based on Dawson-type molybdosulfate and organic dye and its characterization and application in electrocatalysis

A new organicainorganic heteropoly blue based on Dawson-type molybdosulfate and organic dye, (MB)5[S2Mo1VMo17VlO62]ADTCH3CN (MB = C16H18N3S), was synthesized under ambient conditions and characterized by IR, fluorescence spectrum, single crystal X-ray diffraction, magnetism measurement and X-ray photoelectron spectroscopy analysis. X-ray diffraction analysis shows that the polyoxoanions fill in the interspace formed by the MB cations and acetonitrile and interacted by Coulombic forces, complex hydrogen bonds, such as CHa=O, CHa=S and CHa=N, and CHa=I, Ia=I stacking interactions. The XPS data and magnetic measurements show that the polyanion was mixed valence as a result of one electron reduction. The monotonous decrease of IMT from 0.28 cm3 mola1 at ambient temperature down to 0.13 cm3 mola1 K at 2 K indicates the presence of antiferromagnetic interactions among the mono-electron reduction polyanions, S2Mo1VMo17VlO625a. Studies of the photoluminescent properties in acetonitrile solution suggest the presence of the formation of ion pairs of [S2Mo18O62]4a anion and MB cation or charge-transfer transitions between the cationic MB donor and the POM acceptor. Furthermore, the organicainorganic heteropoly blue was used to fabricate a modified carbon paste electrode (1-CPE), which exhibits five pair redox peaks in the potential range a300 mV to 700 mV and more positive first redox potentials than P2Mo18O626a, higher stability and good electrocatalytic activity toward the reduction of nitrite, chlorate, bromate and hydrogen peroxide in acidic (1 M H2SO4) aqueous solution.