Structure and Reactivity of the 1,10-Phenanthroline Complex with Nitrenium Cation

According to the X-ray diffraction data, the cationic fragment in 1-amino-1,10-phenanthrolinium mesitylenesulfonate is a unidentate n-complex whose asymmetric structure is retained in solution. Quantum-chemical calculations by the AM1 method and ab initio (6-31G, 6-31G*, MP2/6-31G) give geometric parameters of the cation, which are similar to those determined experimentally. No dynamic processes involving intra- or intermolecular transfer of the NH2 group was observed up to 100°C by NMR spectroscopy. 1-Amino-1,10-phenanthrolinium cation does not react with 4-methylpyridine and 4-methyl-1,10-phenan-throline with transfer of the amino group, and it fails to react with mesitylene and anthracene at elevated temperature.     

Oxygen adsorption on the surface of a polymer containing coordinated cobalt ions

The formation of adsorbed Co³⁺(O ₂ ^– ) species on the surface of a cobaltcontaining polymer has been established by EPR and reflection spectroscopy in the visible region. The experimental results and quantum-chemical calculations indicate electron transfer from cobalt to the antibonding orbitals of oxygen.

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, , , Co^–3·O ₂ ^– . - .

     

Photochromic and luminescence properties of isomeric forms of the hydronaphthyl radicals

The optical properties of the hydronaphthyl radicals produced upon radiolysis and photolysis of rigid naphthalene solutions in boric acid at 300 K and alcohol, ether and methylcyclohexane at 77 K were investigated. The ESR, absorption and luminescence spectra of the two different isomeric forms of hydronaphthyl radicals have been observed. The estimated values of the lowest electronic transition in α- and β-hydronaphthyl radicals are, respectively: E_α = 2.42 ± 0.03 eV, E_β = 2.66 ± 0.05 eV. It has been found that a reversible photo-induced interconversion between two hydroradicals takes place as well as a dark conversion from the β- to the α-isomer. Analogous photochromic behaviour of the absorption bands of biphenyl, phenanthrene, chrysene and fluorene rigid solutions have also been identified as reversible interconversion between isomeric hydroradicals.     

Effect of flexibility on hydrophobic behavior of nanotube water channels

Carbon nanotubes can serve as simple nonpolar water channels. Here we report computer simulations exploring the relationship between the mechanical properties of such channels and their interaction with water. We show that on one hand, increasing the flexibility of the carbon nanotubes increases their apparent hydrophobic character, while on the other hand the presence of water inside the channel makes them more resistant to radial collapse. We quantify the effect of increasing flexibility on the hydrophobicity of the nanotube water channel. We also show that flexibility impedes water transport across the nanotube channel by increasing the free-energy barriers to such motion. Conversely, the presence of water inside the nanotube is shown to affect the energetics of radial collapse in a water nanotube, an ostensibly mechanical property. We quantify the magnitude of the effect and show that it arises from the formation of energetically favorable low-dimensional water structures inside the nanotube such as one-dimensional wires and two-dimensional sheets.     

Spectral and catalytic properties of a chromium-containing polymeric complex

The spectral and catalytic properties of octahedrally coordinated polymeric Cr³⁺ ions are compared with those of the same ions in-Cr₂O₃. A relationship between the character of the nearest ligand environment of the Cr³⁺ ion (according to spectral data) and the catalytic activity was found. The exchange interaction between Cr³⁺ ions of the polymer chain exerts no significant influence on the catalytic activity.

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Cr³⁺ , Cr³⁺ -Cr₂O₃. Cr³⁺ ( ) . Cr³⁺ .

     

Morphology of solid photochemical decomposition products of silver carboxylates

The formation of solid photochemical decomposition products of silver carboxylates with long linear hydrocarbon chains and its variation in the course of reaction was investigated. At the initial stage of photolysis, particles of silver are formed with the overall situation analogous to that in the case of other silver salts. After the degree of decomposition has reached 20%, the formation of a space-ordered structure of solid products in the form of alternating volume lamellae of paraffin and silver is observed. The average distance from one lamella edge to the next lamella edge is dependent upon the length of the methylene chains of silver carboxylates and the intensity of irradiation. The results obtained are discussed from the point of view of possible spinodal character of decomposition of intermediate solid solution paraffin-silver carboxylate.     

Synthesis and Crystal Structure of Ammonium Dimolybdatouranylate Monohydrate (NH4)2[UO2(MoO4)2] · H2O

The crystal structure of the complex (NH₄)₂[UO₂(MoO₄)₂] · H₂O is determined. The unit cell parameters are a= 7.916, b= 10.885, c= 13.476 Å, = 98.40°, V= 1148.8 ų, space group P2₁/c, Z= 4, (calcd) = 3.452 g/cm³, R= 0.0406, R _w= 0.0850. The coordination polyhedron of the uranium atom is a pentagonal bipyramid with its equatorial plane formed by oxygen atoms of five MoO₄groups.     

The Nuclotron and Nica control system development status

The Nuclotron is a 6 GeV/n superconducting proton synchrotron operating at JINR, Dubna since 1993. It will be the core of the future accelerating complex NICA which is under construction now. The TANGO based control system of the accelerating complex is under development now. The report describes its structure, main features and present status.     

Electrochemical evaluation of the viability of platelets

The difference between the open-circuit redox potentials of a platinum electrode measured in blood plasma before and after the cryolysis of platelets depends linearly on the content of granule-rich platelets in the plasma. This phenomenon can be used to determine the viability of platelets.