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We describe herein our results on the synthesis of bisarylselanylbenzo‐2,1,3‐selenadiazoles through double cross‐coupling reaction. The named compounds were obtained in moderate to good yields by reactions of a range of diaryl diselenides with the 4,7‐dibromobenzo[c][1,2,5]selenadiazole using 20 mol‐% of CuO nanoparticles as a catalyst. In addition, the obtained compounds were investigated regarding their photophysical properties in solution and singlet oxygen generation. Bisarylselanylbenzo‐2,1,3‐selenadiazoles presents strong absorption bands at UV region and red emission properties, depending on the substituent. Geometrical, photophysical and electronic properties of the compounds are characterized with density functional theory calculations. In all derivatives are observed the oxidation process of Se atom, using electrochemical analysis. Also, the quantum yields of photosensitized 1O2 production of the synthesized compounds were slightly lower than the standard, but still displays good ability to generate singlet oxygen species. The ability to generate 1O2 of benzo‐2,1,3‐selenadiazole derivatives after being exposed to light and oxygen allowed us to envisage them as a potential application in photodynamic therapy. The synthesis, photophysics, electrochemical and singlet‐oxygen‐generation properties of bis‐arylselanyl‐benzo‐2,1,3‐selenadiazoles are described. These compounds were obtained in moderate to good yields. The ability to generate 1O2 of benzo‐2,1,3‐selenadiazole derivatives after exposure to light and oxygen allowed us to envisage them as a potential application in photodynamic therapy. [ABSTRACT FROM AUTHOR]

The increasing use of synthetic dyes in commercial food processing has heightened the need for more effective methods of treating industrial wastewaters prior to discharge into the environment. The present report describes the efficient electrodegradation of tartrazine dye in dilute aqueous solution using the electro-Fenton process with Fe (II) or Fe (III) as catalyst and a gas diffusion electrode modified with 5.0% cobalt phthalocyanine. The highest level of color removal (98.4% in 90 min) from solution and the most rapid decay in concentration (kapp 6.0 x 10-2 min-1) of tartrazine dye were achieved in the presence of 0.15 mmol Fe (II). Under these conditions, the amount of total organic carbon (TOC) removed in 90 min was maximal (75%) while energy consumed was minimal (219.0 kWh kg-1 TOC removed). The amount of residual iron was slightly higher than that allowed by the Brazilian authorities for dissolved Fe in wastewaters, indicating that further treatment of the effluent would be necessary. [ABSTRACT FROM AUTHOR]

Abstract: Parabens have been widely used in different industries and can be found in health and personal care products. They are esters of p-hydroxy-benzoic acid associated with breast tumors and classified as endocrine disruptors. This study describes the galvanostatic electrochemical oxidation of methyl paraben (MePa) on a boron-doped diamond anode using current densities in the 1.35 to 21.6mAcm−2 range. The degradation process can be controlled by either charge transfer or mass transport, according to the experimental conditions and rate of mineralization of MePa increased by the current density. The concentration variation as a function of electrolysis time showed that the degradation kinetics follows a pseudo first-order law. A mechanism for the MePa degradation based on reactive intermediates determined by gas chromatography mass spectrometry (GC-MS) is also proposed. [Copyright &y& Elsevier]

Highlights: [•] Effluents containing azo food dye amaranth (AM) represent an environmental hazard. [•] Electrodegradation of AM achieved using a modified gas diffusion electrode (MGDE). [•] Decolorization and mineralization of AM was maximal in presence of 0.15mM Fe2+. [•] Energy consumption for removal of total organic carbon was minimal with 0.15mM Fe2+. [ABSTRACT FROM AUTHOR]

Highlights: [•] The iron (II) phthalocyanine was used as modifier in the GDE for H2O2 generation. [•] At 90min the GDE generated 240mgL−1 of H2O2. [•] The most generation consumption 165kWh for kg of H2O2. [ABSTRACT FROM AUTHOR]