Palladium-catalyzed asymmetric allylation and complex formation involving P,N-bidentate derivatives of (S)-2-(anilinomethyl)pyrrolidine

P,N-Bidentate (S)-2-(anilinomethyl)pyrrolidine derivatives and their complexes with rhodium(i) and palladium(ii) were synthesized. It was demonstrated that these compounds can be used in the Pd-catalyzed asymmetric allylation for the synthesis of chiral methyl 2-phenyl-2-(2-phenyl-o-carboranyl-1)pent-4-enoate.     

Results of the second stage of the study of radiation mechanism of chiral action (RAMBAS-2 experiment)

The results of the second stage of the RAMBAS (Radiation Mechanism of Biomolecular Asymmetry) experiment on the study of the radiation mechanism of the effect on chiral molecules are presented. The optical activity of samples containing racemic mixtures of amino acid complexes with heavy metals before and after their irradiation with an electron flux from a radioactive source was compared. It was shown that irradiation leads to asymmetric decomposition of amino acid complexes and amino acids themselves and chiral asymmetry formation. These results confirm the conclusions made in the first stage of the RAMBAS experiment and can be essential for solving the problem of the origin of life and the formation of chiral asymmetry of the biosphere.     

First quinine-based aryl phosphite: synthesis and application in the Pd-catalyzed enantioselective rearrangement of allylic thiocarbamate

New quinine-based polyfunctional aryl phosphite was synthesized. The phosphorus center in the new compound is characterized by a large cone angle ( = 190°). The new compound can be used in the Pd-catalyzed enantioselective rearrangement of cyclic O-allylic thiocarbamate into S-allylic thiocarbamate in an optical yield of up to 47% with a quantitative conversion.     

Long-wavelength coherent radio radiation of cascades. II. Consideration of the geomagnetic field effect

The long-wavelength limit for radio radiation of extensive air showers was calculated within the cascade theory, taking into account the geomagnetic field effect. The results obtained were compared to the results of Monte Carlo numerical calculations.     

Palladium-catalyzed arylation of bis(4-bromo-2-methylinden-1-yl)dimethylsilane and related compounds

A new procedure was developed for the synthesis of a broad range of ansa-zirconocenes containing bis(2-methyl-4-arylindenyl)dimethylsilane ligands. The method is based on the palladium-catalyzed reaction of halogen-substituted bis(indenyl)dimethylsilanes with various organozinc compounds. The aryl-substituted bridging ligands thus prepared serve as the starting compounds for the synthesis of ansa-zirconocenes, which can be used as components of promising catalysts for propylene polymerization.     

Differential transformations of parabolic second-order operators in the plane

Darboux’s classical results about transformations of second-order hyperbolic equations by means of differential substitutions are extended to the case of parabolic equations of the form Lu = (D _x ² + a(x, y)D _x + b(x, y)D _y + c(x, y))u = 0. We prove a general theorem that provides a way to determine admissible differential substitutions for such parabolic equations. It turns out that higher order transforming operators can always be represented as a composition of first-order operators that define a series of consecutive transformations. The existence of inverse transformations imposes some differential constrains on the coefficients of the initial operator. We show that these constraints may imply famous integrable equations, in particular, the Boussinesq equation.     

Optical generation of terahertz plasmons on comb-shaped surface of metal

The possibilities of a recently proposed (Opt. Express 17, 9323 (2009)) method for generating terahertz surface plasmons on a microstructured (comb-shaped) metal surface using a nonlinear polarization pulse that moves with a superluminal velocity and is induced by an ultrashort laser pulse in a strip of electrooptic material deposited on the surface are theoretically studied. For an arbitrary direction of motion of the nonlinear source along the comb-shaped surface, fields of excited terahertz plasmons and the angular spectral distribution of the radiated energy are calculated. It is shown that the spectral and energy characteristics of plasmons can be efficiently controlled by varying the direction of motion of the source. Conditions (parameters of the comb-shaped structure, direction and velocity of motion of the source) that ensure the maximal efficiency of the optical-to-terahertz conversion are found. The developed method of terahertz generation is promising for surface terahertz spectroscopy.     

Contemporary status of the OPERA experiment for detecting νμ → ντ oscillations in a νμ beam

The first results of the physical stage of the OPERA experiment in 2007, when observation of oscillations of gv_μ into gv_τ started, are discussed. Thirty eight events related to neutrino interactions in emulsion blocks (bricks) are found. The underground muon spectrum and the μ⁺/μ^? ratio are obtained. The results of using detachable emulsion packs (changeable sheets) and accuracy of predictions of neutrino interaction vertices in emulsion layers are discussed. The results of the hardware and software upgrade of the automatic emulsion scanning system PAVIKOM are reported.