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A stable hamburger-like polyoxometalate (POM)-pillared coordination polymer (CP) [Ag15(trz)10][SiW12O40] (Ag15SiW12) (trz = 1,2,3-triazole) has been synthesized and characterized. Single crystal X-ray diffraction (SCXRD) analysis indicates that SiW12 polyanions are sandwiched between adjacent Ag-trz sheets with two distinct types of pores, giving a three-dimensional POM-pillared sheet framework. Inspired by the reported horseradish peroxidase (HRP) and other enzyme mimics, the peroxidase-like activity of Ag15SiW12 was investigated to catalyze oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) by H2O2. Compared with other POM-involved enzyme mimics, Ag15SiW12 exhibits excellent peroxidase-like activity. Detection of H2O2 was also studied in buffer solution, and the result shows broader application range (1-100 μM), faster response time (1 min) and lower detection limit (0.27 μM), which may be ascribed to the distinct structure and maximized synergistic effect of individual components. [ABSTRACT FROM AUTHOR]

An oxidodiperoxidovanadium(V) complex, (NH4)[VO(O2)2(phen)](H2O)2, has been synthesized and structurally characterized. The complex crystallizes in the P21/c space group. The vanadium center is seven-coordinate with pentagonal bipyramidal geometry. The compound was designed in order to develop a VHPO mimic, so it was tested for VHPO activity through the single pot bromination of phenol red to bromophenol blue whereby, it afforded positive response to establish that the complex is indeed a VHPO mimic. In addition, the compound is capable of detection of H2O2. [ABSTRACT FROM AUTHOR]

A novel biosensor for the amperometric detection of hydrogen peroxide was developed based on the co-immobilization of catalase and methylene blue on an A1[SUB2]O[SUB3] sol-gel fabricated glassy carbon electrode. The membrane structure of the sol-gel-immobilized catalase and methylene blue was studied with scanning electron microscopy. Cyclic voltammetric and amperometric measurements demonstrated that methylene blue co-immobilized with catalase in this way displayed good stability and efficiently shuttled electron between the immobilized enzyme and the electrode. Electrocatalytic reduction of H[SUB2]O[SUB2] at the electrode was evaluated with respect to solution pH, operating potential and selectivity. The biosensor was stable at least for 3 weeks. [ABSTRACT FROM AUTHOR]