Vibration spectra and quantum chemical calculation of optoelectronic and force parameters of furazan and furoxan

Vibration spectra of furoxan in liquid and crystalline states are investigated. Force constants and optoelectronic parameters of furazan and furoxan are calculated by MINDO/3. Their values are compared with those obtained by solving inverse spectral problems. It is shown that the band at 1605 cm⁻¹, which is characteristic of all furoxans, is due to vibrations of the C=N(−>0) group. Kazan Technological University. Kazan Construction Engineering Institute. Translated fromZhurnal Strukturnoi Khimii, Vol. 35, No. 6, pp. 54–59, November–December, 1994 Translated by L. Smolina     

Orbital electronegativity concept and its role in energetic crystal chemistry

Development of the orbital electronegativity concept since, 1934 is considered. It is shown that the concept is well substantiated from the quantum chemical viewpoint and is used in such fields of chemistry and crystal chemistry as the Lewis acid-base theory, the reactivity theory, etc. Its application is based on the electronegativity balance principle, which includes not only intraatomic effects but also different interatomic interaction contributions. The concept became a natural tool in modern methods for predicting and modeling the structure and properties of molecules and crystals. M. V. Lomonosov Moscow State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 35, No. 1, pp. 111–127, January–February, 1994. Translated by L. Smolina     

The method of concentrating a substance from a solution in a stationary sorbent layer and its theoretical basis

The principle of concentrating a substance from a mixture flow in a stationary sorbent layer of infinite length that was previously developed for gas chromatography is extended to liquid chromatography. Translated fromIzevestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1063–1065, May, 1997.     

Determination of the potential functions of molecular inversion from experimental data: Current state and problems

Various approximations of the method of determining two-well potential functions of molecular inversion from experimental data (geometrical parameters and inversion level energies) are considered. The potential of the method is illustrated by reference to carbonyl molecules in the lowest excited states. Some of the current problems are discussed. Translated fromZhurnal Strukturnoi Khimii, Vol. 39, No. 5, pp. 947–961, September–October, 1998     

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.     

Regularization method and molecular integrals with singular exponential functions

The regularization principle, which is based on the concept of linearly independent singular functions, makes it possible to calculate many important types of molecular matrix elements arising in the variational LCAO-MO-SCF scheme. This is done using a direct approach that employs reduction of these elements to finite sums of convergent and divergent one-electron integrals. A universal algorithm is developed to calculate two-center one-electron molecular integrals involving both singular and ordinary Slater functions. The numerical stability of the algorithms and the accuracy of the integral calculation are analyzed, and numerical estimates are given. V. I. Vernadskii Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences. Translated fromZhurnal Struktunoi Khimii, Vol. 35, No. 2, pp. 3–11, March–April, 1994. Translated by L. Chernomorskaya     

Structural analogy principle for estimating gas chromatographic retention indices

It is shown that using additive schemes complying with the general principle of structural analogy for all molecular transformations is admissible for calculating gas chromatographic retention indices, which are very important analytical parameters for identification of organic compounds. From this viewpoint, we compare the possibilities of using the homomorphism factors and the fit increments of the retention indices of reagents and products in chemical reactions, including those of some topochemically equivalent hypothetical transformations of the structure and composition of organic molecules. Scientific-Research Institute of Chemistry, St. Petersburg University. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 4, pp. 784–795, July–August, 1996. Translated by L. Smolina     

Calculation of two-center two-electron integrals in the slaters,p,d-basis set for the Ono electron-electron potential

This paper deals with the problems of extending semiempirical MNDO methods to compounds with d-elements. The problem is solved by estimating two-center two-electron integrals (TTI) with the Ono potential modeling interaction between two electrons in a molecule. A scheme for calculating TTI is suggested which uses the expansion of the Ono potential in a series of pairwise products of spherical harmonics centered on two atoms in the molecule. The scheme is stable and efficient for calculations in arbitrary Slater basis sets (including the s,p,d-basis set) and seems to be useful for development of NDDO methods. Scientific Research Institute of Chemistry at N. I. Lobachevskii Nizhnii Novgorod State University. Translated fromZhurnul Strukturnoi Khimii Vol. 35, No. 4, pp. 24–27, July–August, 1994. Translated by L. Smolina     

Synthesis and studies of organic nitrates of the heterofunctional series

N-Nicotinoyltris(hydroxymethy)aminomethane trinitrate hydronitrate, an analog ofN-nicotinoylethanolamine nitrate (the active principle of the antianginal drug nicorandil), was prepared byO-nitration of the corresponding triol with concentrated HNO₃. The structure of the reaction product was established by X-ray structural analysis. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2224–2227, December, 1997.     

Variational method for calculating the anharmonic vibrations of polyatomic molecules using a combined morse-anharmonic basis taking into account the fragmentary structure of molecules

A method of variational solution of anharmonic vibration problems using a mixed Morse—anharmonic basis is proposed. The basis functions are the products of the Morse oscillator eigenfunctions for vibrations of peripheral bonds, the harmonic oscillator eigenfunctions for almost harmonic skeletal and deformation vibrations, and the anharmonic basis functions for essentially anharmonic skeletal and deformation vibrations. The anharmonic basis wave functions are taken as a linear combination of the Morse and harmonic oscillator eigenfunctions. The introduction of the combined Morse—anharmonic functions allows one to factorize the solution of a problem into a series of individual blocks according to the fragmentary structure of molecules. Volgograd Pedagogical University. Translated fromZhurnal Strukturnoi Khimii, Vol. 36, No. 2, pp. 231–238, March–April, 1995. Translated by I. Izvekova     

Phase and structure transformations in water microclusters

The behavior of 12- and 14-molecule water microclusters with ST2 potential in the range of 50–325 K is studied by the molecular dynamics method. Structure and phase transitions, including evaporation of molecules from the clusters and transition through the percolation threshold via hydrogen bonds, were found. Topological, temporal, and energy characteristics of the bond network are analyzed based on the dynamic criterion of hydrogen bonding. Institute of Thermal Physics, Ural Branch, Russian Academy of Sciences. Translated fromZhurmal Strukturnoi Khimii, Vol. 35, No. 1, pp. 64–70, January–February, 1994. Translated by L. Chernomorskaya     

Quantitative determination by PMR spectroscopy of lagochilin in the substance and tablets of the medicinal preparation inebrin

A modified method of additions in PMR spectroscopy was described for quantitative determination of the main active principle in preparations. The effectiveness and reliability of the method was approved for quantitative analysis of the active principle lagochilin in the substance (2.0%) and tablets (0.85%) of the commercial medicinal preparation inebrin. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 124–126, March–April, 2007.     

Spontaneous raman spectroscopic study of the association of liquid γ-butyrolactone molecules

Self-association of γ-butyrolactone molecules in pure liquid state and in nonpolar solutions is studied by spontaneous Raman spectroscopy. The constant and the enthalpy of formation of cyclic dimers in liquid γ-butyrolactone are calculated. Ufa State Aircraft Technical University. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 6, pp. 1099–1103, November–December, 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     

Synthesis of o-carborane-C-carboxylates of certain natural terpene alcohols, sterols, phenols, and camphar oxime

Previously unreported esters 1b–20b were synthesized from natural terpene alcohols, sterols, plant phenols, and camphar oxime (1a–20a) by reaction with o-carborane-C-carboxylic acid chloride. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 434–436, September–October, 2006.     

Quantitative determination of compounds in model acenaphthene-pyrene mixtures

The mutual effect of acenaphthene and pyrene in solid solutions of these compounds is studied by investigating the low-temperature fluorescence spectra of acenaphthene-pyrene mixtures. The “internal filter effect” was measured using the most intense lines in the spectra over a wide range of concentrations. These data may be used in quantitative determinations of mixture components. Moscow State Pedagogical University. Translated fromZhurmal Strukturnoi Khimii, Vol. 36, No. 2, pp. 380–385, March–April, 1995. Translated from L. Smolina     

Method of computer-aided determination of the type of normal vibrations of polyatomic molecules

Correct assignment of calculated and experimental frequencies, as well as corservation of the initial assignment in case of a random coincidence of two frequencies during the solution of an inverse spectral problem, are important problems in spectroscopy of polyatomic molecules. Vibrations are classified according to their form, which is thought to be a more reliable basis for assignment than frequency. We offer a PC program to determine the type of vibrations according to their form (obtained by solving a direct vibrational problem) in a given system of vibrational basis set functions. Optimization of systems of basis set functions for molecules with six-membered rings is discussed. L. Ya. Karpov Physicochemical Scientific Research Institute. Translated fromZhurnal Strukturnoi Khimii, Vol. 36, No. 2, pp. 298–303, March–April, 1995. Translated by L. Smolina     

Optical dissymmetry in crystals due to inhomogeneous distribution of isomorphous components

The mechanisms of optical dissymmetry (optical anomalies) due to inhomogeneous trapping of isomorphous impurities into a crystal are considered using water-soluble systems of potassium dihydrophosphate-ammonium dihydrophosphate and alum as an example. St. Petersburg State University. Translated fromZhurnal Struktumoi Khimii, Vol. 35, No. 5, pp. 60–69, September–October, 1994. Translated by L. Smolina     

Inorganic crystal structure database. Design and operational experience

The Inorganic Crystal Structure Database is a section of the Databank on the Properties of Materials for Electronics that was created at the Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences. The database, which is supplied with constantly updated software, includes quantitative structural data and is designed for solving materials-technology problems. The database contains information on crystal structures of complex and ordinary oxides (including compounds with HTSC properties), chalcogenides, intermetallic compounds, inorganic complexes, etc. More than 20 scientific works on different topics were performed using the database. Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 36, No. 3, pp. 559–563, May–June, 1995. Translated by L. Smolina     

Synthesis and biological activity of certain amino-derivatives of 5α-steroids

Certain 17β-aminoderivatives of 5α-steroids based on tigogenin were synthesized and their antitumor activity was studied. The structures of the synthesized compounds were confirmed by NMR and IR spectroscopy and mass spectrometry. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 263–265, May–June, 2006.