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The electrooxidation of dopamine (DA), uric acid (UA) and their mixture on a gold electrode modified by a self-assembled monolayer of 2-(3,4-dihydroxyphenyl)-1,3-dithialone has been studied by cyclic voltammetry (CV), chronoamperometry and differential pulse voltammetry (DPV). CV was used to investigate the redox properties of the modified electrode at various scan rates and the apparent charge transfer rate constant (k(s)), and transfer coefficient (α) were calculated. The mediated oxidation of DA at the modified electrode under the optimum condition (pH = 7.0) in CV occurs at a potential about 220 mV less positive than that of the unmodified gold electrode. The values of electron transfer coefficients (α), catalytic rate constant (k) and diffusion coefficient (D) were calculated for DA, using electrochemical methods. DPV exhibited a linear dynamic range over the concentration range of 0.2-250.0 μM and a detection limit (3σ) of 0.07 μM for DA. The modified electrode was used for simultaneous determination of DA and UA by DPV. The results showed that the electrode is highly efficient for the catalytic electrooxidation of DA and UA, leading to a remarkable peak resolution (~350 mV) for two compounds. The electrode was used for the determination of DA in an injection sample.

in this study, preparation and characterization of a new magnetic propylsulfonic acid-anchored isocyanurate bridging periodic mesoporous organosilica (iron oxide@pMo-icS-prSo 3 H) is described. the iron oxide@pMo-icS-prSo 3 H nanomaterials were characterized by fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy and field emission scanning electron microscopy as well as thermogravimetric analysis, n 2 adsorption-desorption isotherms and vibrating sample magnetometer techniques. Indeed, the new obtained materials are the first example of the magnetic thermally stable isocyanurate-based mesoporous organosilica solid acid. furthermore, the catalytic activity of the iron oxide@pMo-icS-prSo 3 H nanomaterials, as a novel and highly efficient recoverable nanoreactor, was investigated for the sustainable heteroannulation synthesis of imidazopyrimidine derivatives through the Traube-Schwarz multicomponent reaction of 2-aminobenzoimidazole, c-H acids and diverse aromatic aldehydes. the advantages of this green protocol are low catalyst loading, high to quantitative yields, short reaction times and the catalyst recyclability for at least four consecutive runs. The use of heterogeneous catalysts has been developed because of their desirable properties and addressing many principles of green chemistry. Therefore, development and research in the heterogeneous catalysts has received major consideration due to disadvantages associated with homogeneous catalysts such as catalyst recovery, product separation, corrosion problems and environmental hazards 1-5. Along these lines, development of nanoporous materials with significant improved properties is a new and growing research field in the recent years 6-10. Highlyordered periodic mesoporous organosilicas (PMOs) materials, as a kind of inorganic-organic hybrid mesoporous materials, have attracted significant interest because of their noteworthy properties such as high surface area, narrow pore size distribution, adjustable mesopore diameter, high mechanical and hydrothermal stability, and highly tunable physicochemical properties by varying the nature and extent of the surface functionalization. PMOs which are mainly prepared from bridged organosilane precursors [(R′O) 3 SiR -Si(OR′) 3 ; R: organic bridging group, R′: methyl or ethyl] have found vast applications in various fields such as drug delivery systems, absorption and storage of mechanical energy, gas storage, electronics, sensors, luminescence, adsorbents,

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