N-Pyrrolidine-2-ylmethyl)-2-hydroxy-3-aminopinanes as novel organocatalysts for asymmetric conjugate additions of ketones to α-nitroalkenes

Novel stereoisomeric natural pinane-derived bifunctional catalysts 3a–d bearing a pyrrolidine unit have been synthesized and examined in the asymmetric conjugate additions of carbonyl compounds to α-nitroalkenes. Six-membered cyclic ketones react with β-nitrostyrene derivatives in the presence of (1R,2R,3R,5R)-2-hydroxy-3-((S)-pyrrolidin-2-ylmethylamino) pinane 3b (10 mol %) with high conversion to afford with diastereoselectivity (dr (syn/anti) up to 97/3), the corresponding Michael adducts with enantiomeric purities of up to 88% ee.     

Effect of cerium oxide on the activity of platinum catalysts of hydrogen and CO oxidation

Effective catalytic systems based on Pt/CeO₂-C were prepared. The use of a cerium oxide addition in the substrate stabilized the platinum catalysts against their poisoning with carbon monoxide at room temperature.     

The possibility of anomalous heat transfer in flows with nonequilibrium boundary conditions

The kinetic Boltzmann equation has been solved for the boundary-value problem of heat transfer with boundary conditions in the form of nonequilibrium distributions. Modes with anomalous heat transfer have been revealed in the spatial zones where the signs of the heat flux and temperature gradient coincide (in the classical statement of the problem with equilibrium conditions, heat transfer conventionally occurs in the entire range of physical parameters). Possible experiments aimed at verifying these effects are discussed.     

X-ray analysis of powdered celluloses obtained with the use of Lewis acids

It is established via an X-ray method that the preparation of powdered forms of cellulose under the action of Lewis acids on fibrous hardwood cellulose is accompanied by a change in its crystallographic characteristics. The degrees of crystallinity, the sizes of crystallites, and the periods and monoclinic angles of the unit cells of the obtained powdered celluloses were determined.     

Platinum nanoparticles on the antimony-doped tin dioxide surface: Quantum-chemical modeling

The interaction of Pt₂₉ nanoparticles with pristine and reduced (110) and (100) SnO₂ surfaces doped with Sb has been modeled using the density functional theory method within the generalized gradient approximation (GGA). It has been demonstrated that the introduction of antimony contributes to dispersion of substrate particles and, in some cases, leads to an increase in the energy of interaction with platinum and to the fixation of platinum nanoparticles on the surface.     

Design and Synthesis of New 5-aryl-4-Arylethynyl-1H-1,2,3-triazoles with Valuable Photophysical and Biological Properties

Cu-catalyzed 1,3-dipolar cycloaddition of methyl 2-azidoacetate to iodobuta-1,3-diynes and subsequent Suzuki-Miyaura cross-coupling were used to synthesize new triazoles derivatives: 5-aryl-4-arylethynyl-1H-1,2,3-triazoles. Investigation of their optical properties by using UV absorption and fluorescence emission spectroscopies revealed that all molecules possess fluorescence properties with the values of the Stokes shift more than 100 nm. The photophysical behavior of the two most promising triazoles in polar and non-polar solvents was also studied.     

Phase transformations and structure of Ni–Mn–In alloys with varying ratio Ni/Mn

The fine structure of Ni–Mn–In alloys has been studied when manganese atoms are substituted for nickel atoms in an annealing state. The concentration dependence of the critical temperatures and the structures of the alloys have been discussed. It has been found that, as manganese atoms replace nickel atoms, the structure after annealing is changed from a two-phase (L2₁ + martensite) to single-phase L2₁ structure. The martensitic transformation in Ni₄₇Mn₄₂In₁₁ alloy is accompanied by the formation of modulated 14M martensite.