Raman Scattering Study of Natural and Synthetic Compounds Containing Polyene Chains

Doklady Physics - The dependence of Raman spectra of the molecules containing polyene chains on the conjugation length, structure of side and end groups, and isomer type is analyzed theoretically.     

Crystal Structure of Synthetic High-Chromium Analogue of Yimengite

Crystallography Reports - The structure of a potassium compound with the chemical formula K0.90Ti5.16Cr2.94Fe2.54Mg0.87Al0.22Mn0.30O19 has been investigated by single-crystal X-ray diffraction...     

Investigation of thermal plasma generator of technological function

Experimental results on energy characteristics of electric-arc plasma generator for heating technical nitrogen with the power of up to 500 kW are presented. The features of arc discharge glow, thermal efficiency, and service life of the electrodes were determined under the regime of melting the metallurgical raw material in the test plasma electric furnace.     

Decacyclene Radical Anions Showing Strong Low‐energy Intramolecular Absorption and Magnetic Coupling of Spins in a Hexagonal Network

Two salts of the aromatic hydrocarbon decacyclene, {cryptand[2.2.2](Cs⁺)} (decacyclene^.?) ( 1 ) and {Bu₃MeP⁺}(decacyclene^.?) ( 2 ), were obtained. In both salts, decacyclene^.? radical anions formed channels occupied by cations. However, corrugated hexagonal decacyclene^.? layers could be outlined in the crystal structure of 1 with several side‐by‐side C???C approaches. The decacyclene^.? radical anions showed strong distortion in both salts, deviating from the C₃ symmetry owing to the repulsion of closely arranged hydrogen atoms and the Jahn‐Teller effect. Radical anions showed intense unusually low energy absorption in the IR‐range, with maxima at 4800 and 6000 cm^?1. According to the carculations, these bands can originate from the SOMO‐LUMO+1 and SOMO‐LUMO+2 transitions, respectively. Radical anions exhibited a S=1/2 spin state, with an effective magnetic moment of 1.72 μ_B at 300 K. The decacyclene^.? spin antiferromagnetically coupled with a Weiss temperature of ?11 K. Spin ordering was not observed down to 1.9 K owing to spin frustration in the hexagonal decacyclene^.? layers.     

Two-Stage Technique of Controlling the Heat Release Distribution

Physics of Atomic Nuclei - A two-stage method is proposed for controlling the regulators in the fuel burnup process during a single operating period. At the first stage, the coefficient of the heat...     

Aza-substitution,benzo-annulation effects and catalytic activity of <Emphasis Type="Italic">β</Emphasis>-octaphenyl-substituted tetrapyrrolic macroheterocyclic cobalt complexes. I. heterogeneous catalysis

The influence of the size of conjugated π-system on catalytic activity of cobalt complex with β-octaphenylporphyrin and its tetraaza-, tetrabenzo and tetrabenzotetraaza derivatives was studied in present work. It is found that catalytic activity for oxidation of sulfur-containing compounds increases under extension of conjugated macrocycle system according to the following series CoP < CoBP ≤ CoPz < CoPPz ? CoPc.     

Molecular Structure,Thermodynamic and Spectral Characteristics of Metal-Free and Nickel Complex of Tetrakis(1,2,5-thiadiazolo)porphyrazine

The Knudsen effusion method with mass spectrometric control of the vapor composition was used to study the possibility of a congruent transition to the gas phase and to estimate the enthalpy of sublimation of metal-free tetrakis(1,2,5-thiadiazolo)porphyrazine and its nickel complex (H₂TTDPz and NiTTDPz, respectively). The geometrical and electronic structure of H₂TTDPz and NiTTDPz in ground and low-lying excited electronic states were determined by DFT calculations. The electronic structure of NiTTDPz was studied by the complete active space (CASSCF) method, following accounting dynamic correlation by multiconfigurational quasi-degenerate second-order perturbation theory (MCQDPT2). A geometrical structure of D_2h and D_4h symmetry was obtained for H₂TTDPz and NiTTDPz, respectively. According to data obtained by the MCQDPT2 method, the nickel complex possesses the ground state ¹A_1g, and the wave function of the ground state has the form of a single determinant. Electronic absorption and vibrational (IR and resonance Raman) spectra of H₂TTDPz and NiTTDPz were studied experimentally and simulated theoretically.     

Electrical conductivity of lyotropic phases of dodecylbenzenesulphonates with Li+, Na+, and K+ ions in water

The electrical conductivity of dodecylbenzenesulphonate (DoBS) ionic lyotropic liquid crystal of the systems: LiDoBS (dodecylbenzenesulphonic acid lithium salt)/water, NaDoBS (dodecylbenzenesulphonic acid sodium salt)/water, and KDoBS (dodecylbenzenesulphonic acid potassium salt)/water were investigated by impedance spectroscopy in the frequency range from 0.5 Hz to 0.5 MHz. The electrical conductivity of lyotropic LiDoBS was higher than that of isotropic phase. The electrical conductivity isotropic KDoBS and NaDoBS was higher than the conductivity of lyotropic ones. The temperature dependence of electrical conductivity was investigated in the systems LiDoBS/water and KDoBS/water for different phases. The activation energy of electrical conductivity is lowest for the normal hexagonal phase LiDoBS/water. Such systems based on anionic surfactants are of interest as the electrolyte for the supercapacitors.     

Spectral,Luminescent, and Photochemical Properties of Derivatives of Hydrogenated Furo- and Thienoquinolines

High Energy Chemistry - New derivatives of hydrogenated furo- and thioenoquinolines have been synthesized, and their spectral and luminescent properties and photochemical transformations have been...     

Structural Specific Features of Solid Solutions NdxGd1 – xCr3(BO3)4

Optics and Spectroscopy - Optical investigations of crystals of solid solutions NdxGd1&nbsp;–&nbsp;xCr3(BO3)4, 0.01 ≤ x ≤ 1, have been performed. Absorption spectra in the...