Synthesis of 1-aryl-1,2,3,4-tetrahydro-9H-pyrido[3,4-b]indoles (1,2,3,4-tetrahydro-β-carbolines) under high pressures

The reactions of aromatic aldehydes with tryptamine (1) in solvents of different polarity were studied. The yields of carbolines in the chosen media decrease with an increase in the donating properties of the aryl substituent, but they markedly increase at a high pressure (5 kbar), especially for compounds with electron-donating aryl groups. The phase transition of dioxane at 5 kbar also sharply increases the yields of the target products.     

Identification of the polymerized orthorhombic phase of C60 fullerene

It is established by x-ray diffraction and Raman scattering that the polymerization of C₆₀ fullerene at 1.5 GPa and 723 K leads to the formation of an orthorhombic phase that is different from the previously identified high-pressure orthorhombic phase. It is determined by a calculation of the optimal packing of linear C₆₀ polymers by the method of atom-atom potentials that the energetically favorable structure of the orthorhombic phase belongs to the space group P n n m and not the previously proposed group I m m m. The computed value of the rotation angle of the polymer chains that corresponds to the minimum packing energy was equal to 61°. The mechanisms leading to the formation of the polymerized phases are discussed on the basis of the results obtained. Pis’ma Zh. éksp. Teor. Fiz. 66, No. 2, 110–114 (25 July 1997)     

催化光度法测定痕量钒——钒(Ⅴ)-溴甲酚紫-过氧化氢体系

催化光度法测定钒已有报道[1～3],在0.45 mol·L-1磷酸介质及加热条件下,过氧化氢氧化溴甲酚紫褪色反应非常缓慢,而痕量钒对此反应具有较高的催化活性,且在一定浓度范围内,钒量与褪色反应程度呈线性关系,据此可建立测定痕量钒的方法.方法的检出限为1.9×10-6g·L-1,测定范围为0.003～1.8 mg·L-1.方法操作简便,重现性好,用于钢样中痕量钒的测定,结果满意.     

N,N′-Acylated 2,4-diazabicyclo[3.3.1]nonanes and 2,4-diazabicyclo [3.2.1]octanes from alicyglic bisazomethines

Conclusions Benzoylation of bisazomethine derivatives of 1,3-diaminocyclohexane and 1,3-diamino-cyclopentane has given 3-aryl-2,4-dibenzoyl-2,4-diazabicyclo₁3.3.1]-nonanes and 3-aryl-2,4-dibenzoyl-2,4-diazabicyclo[3.2.1]octanes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 835–839, April, 1988.The authors thank V. V. Yakubënka for the gift of samples of cis- and trans-1,3-diaminocyclo-hexane.     

Residual polarization of non-coherently backscattered linearly polarized light: the influence of the anisotropy parameter of the scattering medium

The effect of preservation of the residual polarization of backscattered light in the case of multiply scattered disordered media illumination by a linearly polarized plane wave is examined using the path-integral approach and Monte Carlo simulation. Disordered ensembles of non-interacting dielectric particles are considered as the model of scattering media. The influence of the anisotropy parameter of the scattering system on the degree of residual polarization is analysed. Experimental results obtained for various scattering systems at different wavelengths of illuminating light are in satisfactory agreement with the results of theoretical analysis and Monte Carlo simulation. The dependence of statistical properties of the polarization states of backscattered field partial components, such as probability distributions of ellipticity, on the anisotropy parameter is studied.     

Photoelectrochemical properties of thin films on titanium obtained by thermal,electrochemical, or sol-gel method

Journal of Solid State Electrochemistry - The photosensitivity of the titanium dioxide films on titanium substrate formed by the electrochemical, thermal, or sol-gel method was compared under the...     

Analysis of the Results of Astroclimate Research at the Kara-Dag Radioastronomical Station in Crimea and the Possibilities for Reducing the Influence of the Atmosphere on Millimeter-Band Radioastronomical Observations

Journal of Experimental and Theoretical Physics - The results of astroclimate research at the Kara-Dag radioastronomical station (Crimea) from July 22 to September 21, 2017, are presented....     

Asymmetry of Domain Walls Oscillations in Iron Garnet Crystals with Stripe Domain Structure Drift in Harmonic and Pulsed Magnetic Fields

Physics of the Solid State - An asymmetric displacement of domain walls during their oscillatory motion and an asynchronous change in the velocities of neighboring domain walls have been revealed...     

Theoretical Studies on the First Hyperpolarizabilities of One-dimensional Donor-bridge-acceptor Chromophores

The ground-state dipole moments and second-order nonlinear optical （NLO） properties of a series of one-dimensional （1D） chromophores with donor-bridge-acceptor （D-B-A） structures have been investigated by using the second-order MФller-Plesset （MP2） and density functional theory （DFT） methods with the basis set of 6-31＋G（d）. According to the calculated results, the relationship between the molecular static first hyperpolarizability （βμ） and the directions of electron transition has been summarized. In terms of the sign of βμ, these 1D organic chromophores were classified into two categories： type Ⅰ with negative βμ and type Ⅱ bearing positive βμ. The analyses show that the remarkable difference of the first hyperpolarizabilities between Ⅰ and Ⅱ chromophores is associated mainly with the electrostatic interaction between terminal groups and the transport electrons in excited states. Moreover, different from the popular viewpoint, the obtained results also show that most of this series of 1D D-B-A molecules are more charge-separated in the ground states than in the excited states. As a whole, this theoretical investigation, to some extent, can be considered as a useful reference in designing the NLO chromophores with large first hyperpolarizabilities.     

Shear Elastic Properties of HTSC Ceramics in the Region of Superconducting Transition

Technical Physics - The shear elastic properties of YBa2Cu3O7 –x high-temperature superconducting (HTSC) ceramics are studied near the superconducting transition at a temperature of 91.3 K...