Synthesis and properties of crystalline fullerene hydrides

The interaction of crystalline fullerence C₆₀ with highly pure hydrogen, which was evolved from hydrides of intermetallic compounds of rear-earth metals and nickel, was studied. Crystalline fullerene hydrides containing from 10 to 30 hydrogen atoms per fullerene molecule were synthesized (1.0–2.5 MPa and 300–673 K). Crystalline hydrides release hydrogen at 800 K with retention of the structure of the fullerene molecule. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2093–2096, October, 1998.     

Matrix method of conformational optimization. Application to cyclic and polyhedral water clusters

A matrix method for conformational optimization of quasi-one-dimensional molecular structures is suggested. The method is used to determine cyclic and polyhedral configurations of water clusters with the maximal number of stable trans-conformations of molecular pairs forming hydrogen bonds. Institute of Earth Cryosphere, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 1, pp. 107–115, January–February, 1996 Translated by L. Smolina     

Combination of ionic and metal-olefin bonds in crystalline copper(I) π-complexes

The ionic field effect on metal-olefin π-binding is considered for 24 Cu(I) compounds based on X-ray diffraction data. Structural features due to Cu…(C=C)−H…An and N−H…An bridges in cationic and zwitterionic π-complexes, respectively, are discussed. Parity of metal-olefin and hydrogen bonds in formation of these structures is shown. I. Franko Lvov State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 35, No. 5, pp. 109–119, September–October, 1994. Translated by A. Arbuznikov     

Solvent-induced allylic rearrangements in poly(trichlorobutadiene) chains

It was established by Fourier-transform IR and¹H NMR spectroscopy that a portion of the units of poly(1,1,2- and 1,2,3-trichlorobuta-1,3-diene) chains rearrange with migration of the allylic chlorine (1–4%) and allylic hydrogen (3–10%) under the influence of chloroform. Rearrangement with the migration of hydrogen under the influence of CDCl₃, CCl₄, and THF was also observed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 763–768, April, 1997.     

Effect of structural characteristics of water on the infrared absorption and raman spectra

An analysis of band contour in the IR absorption (overtone region) and Raman spectra of water suggests that the high-frequency components of spectral bands correspond to a single continuous distribution in energy of H-bonds. A local increase in the probability density function at high frequencies, which leads to an increase in the population of states with weak hydrogen bonds, is caused by the specific behavior of the angular dependence of the energy of hydrogen bonds between water molecules. St. Petersburg State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 36, No. 3, pp. 467–472, May–June, 1995. Translated by I. Izvekova     

Quantum chemical study of the intramolecular transfer of hydrogen in o- methylacetophenone and 1- alkylanthraquinones

The geometries and formation enthalpies of reagents, products, and triplet intermediates in the reaction of photoenolization of o- methylacetophenone and 1- methylanthraquinone are calculated by semiempirical quantum chemical methods. It is shown that the triplet intermediate is a triplet Σπ- biradical. The geometries and formation enthalpies of the transition state of the thermal transfer of the hydrogen atom in 9- hydroxy- 1,10- anthraquinone- 1- methide are calculated. The MNDO semiempirical methods give significantly exaggerated activation enthalpies in the thermal transfer of the hydrogen atom. Translated fromZhumal Strukturnoi Khimii, Vol. 38, No. 4, pp. 645–654, July–August, 1997.     

Conformational combinatorial analysis of polyhedral water clusters

A topological model of polyhedral water clusters that takes into account the conformational type of hydrogen bond is suggested. The polyhedral structures are classified according to the number of transand cis-conformations. The structural features of clusters with the maximal number of more stable trans-conformations are studied. Institute of Earth Cryosphere, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 1, pp. 98–106, January–February, 1996 Translated by L. Smolina     

Synthesis of the scalemic form of alkaloid (−)-dipthocarpamine

The scalemic form of active alkaloid (−)-dipthocarpamine was synthesized by asymmetric oxidation ofN-isopropyl-N′-(methylthiohexyl)urea with hydrogen peroxide in the presence of vanadium(IV) complexes with chiral Shiff's bases. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 564–565, March, 2000.     

Buddledin C from Pulicaria prostrata and selective synthesis of its epoxy derivative

The structure of the sesquiterpene ketone buddledin C isolated from Pulicaria prostrata (Gilib.) Aschers., was confirmed by XSA. The stereochemistry of its epoxide, which was formed selectively by treating it with hydrogen peroxide in alkaline solution, was proposed based on quantum-chemical and molecular-mechanical calculations. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 34–37, January–February, 2006.     

Photocatalytic production of hydrogen in systems based on Cd<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Zn<Subscript>1–<Emphasis Type="Italic">x</Emphasis></Subscript>S/Ni<Superscript>0</Superscript> nanostructures

A relation was established between the composition of Cd _x Zn_1–x S nanoparticles and their ability to accumulate excess negative charge during irradiation. The rate of expenditure of the accumulated charge depends on the composition of the nanoparticles and is determined by their electric capacitance. A correlation was found between the photocatalytic activity of the Cd _x Zn_1–x S nanoparticles in the release of hydrogen from solutions of Na₂SO₃, their composition, and their capacity for photoinduced accumulation of excess charge. It was shown that Ni⁰ nanoparticles photodeposited on the surface of Cd _x Zn_1–x S are effective cocatalysts for the release of hydrogen. It was found that Zn^II additions in photocatalytic systems based on Cd _x Zn_1–x S/Ni⁰ nanostructures have a promoting action on the release of hydrogen from water–ethanol mixtures. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 45, No. 1, pp. 8–16, January-February, 2009.     

Prediction of the vaporization enthalpy based on modified Randi? indices. I. Monohydric alcohols

The vaporization enthalpy of monohydric alcohols with different structures under normal conditions is calculated using a modified Randič method with an error comparable to the experimental one. The energy of hydrogen bonds in alcohols is determined and shown to be constant and independent on the alcohol structure. Original Russian Text Copyright ? 2009 by E. L. Krasnykh __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 50, No. 3, pp. 577–581, May–June, 2009.     

Structure effects of weak interactions in heterodesmicπ-complexes of copper(I)

Structural effects: disordering, twinning, polymorphism, and morphotropism due to substitution of halide atoms are considered using the results of X-ray diffraction analysis of 18 olefinic π-complexes of Cu(I). These effects are associated with the heterodesmic character of compounds, in particular, with weak interactions such as lengthened coordination bonds and hydrogen contacts. Ukrainian State Wood Technology Institute. Translated fromZhurnal Strukturnoi Khimii, Vol. 39, No. 1, pp. 98–107, January–February, 1998.     

Water clusters in supramolecular inclusion hydrates. Crystal structure of decaazatricyclo[28.2.2.213.16]tetratriacontane nanohydrate

Inclusion compounds of solvate water molecules in a crystal matrix are investigated by X-ray diffraction analysis of a macrocyclic polyamine decaazatricyclo[28.2.2.2^13.16]tetratriacontane nanohydrate (I). When included in a crystal, water molecules are bonded by water-water (O-H...O) and water—macrocycle (0-H...N and N-H...O) hydrogen bonds, forming a linear cluster. Translated fromZhurnal Strukturnoi Khimii, Vol. 40, No. 5, pp. 993–1001, September–October, 1999.     

Sulfurization of polymers

Polyethylene is exhaustively sulfurized by elemental sulfur at 160–365 °C to release hydrogen sulfide and form black lustrous powders (sulfur content ≈80%) that possess electric conductivity (10⁻⁶–10⁻⁸ S cm⁻¹ when doped with I₂). Elemental analysis data, IR spectra, X-ray patterns, DSC-TGA. derivatographic data, electric conductivity, and mass spectrometric characteristics of the polymers synthesized suggest the presence of fused polythienothiophene and polynaphthothienothiophene blocks in the polymers. For Part 1, see Ref. 1 Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 865–871, May, 2000.     

Hydrogen bonds involving C-H groups of 1,1,2,2-tetrabromoethane and their effect on the conformation equilibrium

The solvent and polymer matrix effects on the conformation equilibrium in 1,1,2,2-tetrabromoethane (TBE) are investigated by IR spectroscopy. The free energy differences (ΔG₀) of TBE conformations correlate with the dielectric permittivity function of the medium. A pronounced solvent effect on the absolute integrated intensities of the IR bands arising from the C-H stretching vibrations indicates H-bonding between the C-H groups of TBE and the solvent. The enthalpies of specific interactions due to hydrogen bonding were estimated using the intensity rule (1–3 kcal/mole). The absence of correlations between ΔG₀ and the solvent basicity parameter leads us to conclude that the trans- and gosh-conformers of TBE form nearly equally strong hydrogen bonds. Kazan State University. Kazan State Technological University. Translated fromZhurnal Strukturnoi Khimii, Vol. 39, No. 3, pp. 478–483, May–June, 1998. This work was supported by RFFR grant No. 96-03-32171a.     

Structural,vibrational, and energy characteristics of halide molecules of group II–V elements

Correlations between the internuclear distances r(M-X), the bond energies E(M-X), and the valence force constants f_r for di- and trihalides of Group II–V elements are established. Some missing values are estimated. Ivanovo State Chemical Technological Academy. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 5, pp. 859–875, September–October, 1996. Translated by L. Smolina Ivanovo State Chemical Technological Academy. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 5, pp. 859–875, September–October, 1996.     

Redox properties of rhodium diene-cyclopentadienyl complexes

The electrochemical behavior of rhodium sandwich complexes containing η⁴-pentamethylcyclopentadiene or tetramethylfulvene fragments has been studied by cyclic voltammetry. The complexes undergo one-electron oxidation to give unstable 17-electron radical cations which are converted into rhodocenium salts as a result of elimination or uptake of hydrogen or C-C bond cleavage. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1802–1805, October, 1993.     

Mechanisms of interactions between atomic hydrogen and vacancies in the silicon crystal lattice

SCF-MO-LCAO calculations in the MINDO/3 approximation were used to determine some mechanisms of interactions between atomic hydrogen and silicon lattice vacancies and between interstitial silicon atoms and hydrogen-charged lattice vacancies. In a completely hydrogen-charged vacancy, hydrogen atoms are localized on the Si−Si bond of the second coordination sphere with respect to the vacancy, so that the crystal lattice is ordered around the vacancy. The capture of atomic hydrogen in any charge state by a vacancy significantly decreases the potential barriers of the annihilation of the Frenkel pairs. After an interstitial atom has been captured by a hydrogen-charged vacancy, it is energetically profitable for the hydrogen atom to transfer to a neighboring vacancy. The interaction mechanisms revealed are consistent with the model of the accelerated annealing of lattice vacancy defects by high-frequency plasma treatment. In addition, the calculation results suggest that materials with hydrogen-charged silicon should be more stable to ionizing radiation than materials with hydrogen-free silicon, since the probability that the interstitial silicon involved in the Frenkel pair will be recaptured by the lattice point is rather high. Kiev Polytechnical Institute. Translated fromZhurnal Strukturmoi Khimii, Vol. 37, No. 1, pp. 22–28, January–Feburary, 1996. Translated by I. Izvekova     

Hydrogenation of fullerites in the presence of intermetallic compounds or metals

Fullerene hydrides containing 24–26 H atoms per fullerene molecule were obtained by hydrogenation of solid-phase mixtures of fullerenes with either intermetallic compounds LaNi₅, LaNi_4.65Mn_0.35, CeCo₃ or V and Pd metals with gaseous hydrogen at 1.0–2.5 MPa and 573–673 K. These fullerene hydrides decompose at 800 K with evolution of H₂. Upon subsequent heating to 1000 K, vanadium reacts with fullerene to yield a cubic phase of vanadium carbide. The intermetallic compounds react with fullerene with the formation of a metallic phase of the 3d-metal and destruction of fullerene. Palladium does not react with fullerene. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 679–683, April, 1997.     

Crystal and molecular structure of 2-(n-tosylamino)benzylidene-text-butylimine

The structure of a new Schiff base, o-tosylaminobenzaldehyde, which has a bulky aliphatic substituent at the azomethine N atom, was determined by X-ray diffraction analysis. The structure contains an intramolecular hydrogen bond N-H...N, flattening the azomethine molecule and closing the six-membered quasiaromatic H-ring. Scientific Research Institute of Physical and Organic Chemistry, Rostov State University. N. S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 3, pp. 544–549, May–June, 1996.