3-Polyfluoroalkyl-1,5-diphenylpyrazoles in Suzuki Cross-Coupling Reactions

Russian Journal of Organic Chemistry - Suzuki cross-coupling was used for modification of 3-polyfluoroalkyl-1-phenylpyrazoles at the position C4. The synthesized 4-bromo- and 4-phenyl derivatives...     

Study of melanin localization in the mature male Calopteryx haemorrhoidalis damselfly wings

Damselflies Calopteryx haemorrhoidalis exhibiting black wings are found in the western Mediterranean, Algeria, France, Italy, Spain and Monaco. Wing pigmentation is caused by the presence of melanin, which is involved in physiological processes including defence reactions, wound healing and sclerotization of the insect. Despite the important physiological roles of melanin, the presence and colour variation among males and females of the C. haemorrhoidalis species and the localization of the pigment within the wing membrane remain poorly understood. In this study, infrared (IR) microspectroscopy, coupled with the highly collimated synchrotron IR beam, was employed in order to identify the distribution of the pigments in the wings at a high spatial resolution. It was found that the melanin is localized in the procuticle of the C. haemorrhoidalis damselfly wings, distributed homogeneously within this layer, and not associated with the lipids of the epicuticle.     

Synthesis of functionally substituted benzaldehydes

A new method of synthesis of functionally substituted benzaldehydes by catalytic debromometoxylation of dibromomethylarenes with benzaldehyde dimethyl acetal has been suggested. Anhydrous zinc chloride has been used as a catalyst. Being soft Lewis acid, it formed no strong complex with aldehyde group and other functional groups. The initial acetal has been readily recovered by the treatment of benzaldehyde isolated from the reaction mixture with trimethyl orthoformate.     

Properties of electrorheological fluids based on nanocrystalline cerium dioxide

Effect of conditions of nanocrystalline cerium dioxide preparation from aqueous solutions on its composition and physicochemical properties and on dielectric characteristics of CeO₂ suspensions in polydimethylsiloxane PMS-20 and the magnitude of electrorheological effect for these suspensions has been analyzed. Relationship between physicochemical properties of CeO₂ nanopowders and polarization and functional characteristics of electrorheological fluids derived therefrom has been established.     

Sorption and cytotoxicity of zinc on hydroxyapatite

The preparation, physicochemical properties, and cytotoxicity of zinc-containing hydroxyapatites (HAP) were considered for further using HAP as carriers for zinc-containing drugs and radiopharmaceuticals.     

Influence of annealing at temperatures above the solidus temperature on the structure and galvanomagnetic properties of Bi<Subscript>92</Subscript>Sb<Subscript>8</Subscript> solid-solution thin films

The influence of the annealing temperature from the interval between the solidus and liquidus temperatures of Bi₉₂Sb₈ solid solution on its structure and galvanomagnetic and thermoelectric properties has been studied. It has been shown that films of bismuth–antimony solid solution grown by thermal evaporation in a vacuum will have a large-grained structure after annealing at temperatures higher than the solidus temperature of the solid solution. It has been found that these films offer the lowest resistivity, the highest relative magnetoresistance, and the highest mobility of charge carriers. As the annealing temperature approaches the liquidus temperature, the probability that a dendritic structure will form and antimony-enriched regions will appear grows. This causes an increase in the charge carrier concentration and a decrease in the resistivity with a decrease in the relative magnetoresistance and charge carrier mobility.     

Hydrothermal Microwave Synthesis of MnO<Subscript>2</Subscript> in the Presence of Melamine: The Role of Temperature and pH

Nanocrystalline manganese dioxide have been prepared by hydrothermal microwave treatment of mixed solutions of potassium permanganate and 2,4,6-triamino-1,3,5-triazine (melamine) in pH range 0.5–3. Phase and chemical composition and morphology of the samples was studied by XRD, Raman spectroscopy, and SEM. Conditions (solution pH and temperature) for the formation of single phase MnO₂ powders (α-MnO₂, γ-MnO₂, δ-MnO₂, and δ*-MnO₂) under hydrothermal microwave treatment were determined.