Activity of 5% CuO/Ce1 – xPrxOy Catalysts in the Reaction of Carbon Monoxide Oxidation with Oxygen in an Excess of Hydrogen

Kinetics and Catalysis - The 5% CuO/Ce1 – xPrxOy catalysts were synthesized on the basis of CeO2 and PrO2 oxides and Ce1 – xPrxOy solid solutions with x =...     

Indole-containing 2-Nitroethenylphosphonates: Synthesis and Structure

A method was developed for preparing first representatives of phosphorylated nitrovinylindoles, bis(2-chloroethyl) 1-(indol-3-yl)- and bis(2-chloroethyl) 1-(1-alkylindol-3-yl)-2-nitroethenylphosphonates, and the structures of these compounds were studied. The spectroscopic data and results of dipole moment measurements show that the molecules have E configuration with s-cis arrangement of the multiple bond and phosphoryl group. X-ray studies have shown that the molecules of the first compound, having the E-s-cis form in the solid phase also, exist in the crystal in the form of enantiomeric pairs. They are involved in inter- molecular hydrogen bonds to form infinite chains.     

Nanoparticles based on gadolinium(iii) and europium(iii) complexes for biovisualization

Complexes Ln(TTA)₃ and [Ln(TTA)₃·1] (Ln = Eu, Gd; ТТА is thenoyltrifluoroacetyl-acetonate; 1 is 2-(5-chlorophenylene-2-hydroxy)-2-phenylethylene-bis(2-methoxy)phosphine oxide) in individual form, and as a part of a core of the polyelectrolyte stabilized colloids have been studied by Mössbauer spectroscopy and X-ray powder diffraction. The photophysical and colloidal characteristics of the solutions of polyelectrolyte nanoparticles were studied in water, artificial cerebrospinal fluid solution, solution of bovine serum albumin, and human blood serum. A stability of a luminescent response of the nanoparticles in solutions of bovine serum albumin and human blood serum at 37 °С for 2 hours has been revealed. This is a prerequisite for the potential application of studied nanoparticles for biovisualization.

     

The Effect of the Copper Oxide Content and Support Structure in (0.5−15%)СuО/ZrO<Subscript>2</Subscript> Catalysts on Their Activity in the CO Oxidation Reaction with Oxygen in an Excess of Hydrogen

The dependence of the activity of СuO/ZrO₂ catalysts in the CO oxidation reaction with oxygen in the presence of an excess of hydrogen and adsorption of СО over them on the CuO content (0.5 to 15%) and the structure of the support ZrO₂, monoclinic (М), tetragonal (Т), or mixed (М + Т) has been studied. It has been found that the activity of CuO/ZrO₂ is associated with the adsorption capacity of the samples for СО at 20°С. Thus, 5%CuO/ZrO₂(Т + М) and 5% CuO/ZrO₂(Т) samples, which exhibit the maximum activity (the СО conversion over them is 80–85% at 160°С), also possess a high chemisorption capacity towards CO (~2.2 × 10²⁰ molecules/g). At the same time, CuO/ZrO₂(М) samples with the CuO contents of 1 and 5% do not chemisorb СО and are inactive in the reaction at 160°С. The СО conversion over them does not exceed 32–36% at 250°С. On the basis of the data obtained by X-ray phase analysis, temperature-programmed reduction with Н₂, temperature-programmed СО desorption, and electron paramagnetic resonance, a conclusion has been made that at low temperatures СО oxidation proceeds over Cu_nO_m clusters that are located on ZrO₂(Т) crystallites. With the increase in the copper oxide content from 0.5 to 5%, the activity of the clusters increases, while the reaction temperature decreases. CuO_m oxo complexes and particles of the СuO phase do not exhibit catalytic activity. The reasons for the low activity of the CuO/ZrO₂(М) samples with the CuO contents of 1 and 5% in the СО oxidation and adsorption processes are discussed. The mechanism of the low-temperature СО oxidation with oxygen in an excess of hydrogen over a 5% CuO/ZrO₂(Т + М) catalyst is considered.     

Kinetics of the Thermal Desorption of Atomic Oxygen during Transformations BiO2 – x→ β-Bi2O3→ α-Bi2O3

The thermal desorption of atomic oxygen during the transformations BiO_{2 – x} -Bi₂O₃ -Bi₂O₃is shown to be due to the removal of overstoichiometric oxygen from the bulk of -Bi₂O₃. Oxygen formed at the first stage is desorbed in a molecular form. The maximum desorption rate of atomic oxygen is found before the phase transformation -Bi₂O₃ -Bi₂O₃. The activation energy of the diffusion of excess oxygen in the -Bi₂O₃lattice is 30 kcal/mol.     

An amperometric monoamine oxidase biosensor for determining some antidepressants

An amperometric biosensor based on a platinum screen-printed electrode and immobilized monoamine oxidase is developed to determine antidepressants of different classes. Petylyl, pyrazidol, and flu-oxetine can be determined with determination limits of 8 × 10^?9, 8 × 10^?7, and 8 × 10^?10 M, respectively. A procedure is proposed for determining fluoxetine in tablets. It is shown that petylyl can be selectively determined by an immunochemical technique using the developed biosensor and immobilized antibodies in the concentration range from 1 × 10^?4 to 1 × 10^?8 M.     

Synthesis and Structure of 1-Bromo-1-nitro-2-piperidino(cyclohexylamino)-2-phenylethenes

A preparation method was developed for new representatives of halonitroenamines, 1-bromo-1-nitro-2-piperidino(cyclohexylamino)-2-phenylethenes. Both molecules possess E configuration and are of high polarity.