Calculation of normal vibrations of adenine and its deuterium-substituted analogs

The vibrational spectra of adenine and its deuterium-substituted analogs are calculated in the valence force field approximation. The frequencies and forms of normal vibrations of the molecule at 1700–300 cm^-1 are interpreted. Translated fromZhumal Struktumoi Khimii, Vol. 38, No. 2, pp. 324–333, March–April, 1997.     

Vibronic coupling in quasidegenerate electronic states of metal porphyrin molecules

In the absorption spectra of isocyclically substituted metal porphyrins, the inactive second electron transition produces a significant effect on the vibrational structure of the fluorescence spectra due to vibronic borrowing of intensitites. These vibronic interactions involving the second electron level are universal for the spectra of metal porphyrins. Institute of Molecular and Atomic Physics, Belarus Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 36, No. 2, pp. 366–369, March–April, 1995. Translated by L. Smolina     

New flavanones from Scutellaria phyllostachya roots

The new natural flavanones (+)-5,2′-dihydroxy-6,6′,7-trimethoxyflavanone and (+)-5,2′-dihydroxy-6,6′,7,8-tetramethoxyflavanone in addition to the known flavones chrysin, norwogonin, and wogonin were isolated from Scutellaria phyllostachya roots. The structures of the isolated compounds were established using IR, UV and PMR spectra. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 24–25, January–February, 2008.     

Far IR and Raman vibrational spectra of nitramines

Vibrational spectra of several nitramines in the long-wave region (50–450 cm⁻¹) were studied. The frequencies of intra- and intermolecular vibrations were separated and a tentative assignment of the frequencies of self-associative complexes was performed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2241–2244, November, 1998.     

Cyclochivinoside B from the aerial part of <Emphasis Type="Italic">Astragalus chivensis</Emphasis>

The known glycoside aleksandroside I and the new cycloartane glycoside cyclochivinoside B, 24S-cycloartan-3β,6α,16β,24,25-pentaol 3,25-di-O-β-D-glucopyranoside, were isolated from the aerial part of Astragalus chivensis. Their structures were established using chemical transformations and two-dimensional spectra (TOCSY, ROESY, HMBC, HSQC, COSY). __________ Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 138–140, March–April, 2007.     

Novel syntheses of symmetrical 2,5-diaryl-1,3,4-oxadiazoles and 1,4-phenylenebis-1,3,4-oxadiazoles

The reactions of trichloromethylarenes with excess hydrazine hydrate in ethanol gives symmetrical 2,5-diaryl-1,3,4-oxadiazoles in 68–96% yields. The reaction of 1,4-bis(trichloromethyl)benzene with acylhydrazines in an ethanol-pyridine mixture gives the corresponding substituted or unsubstituted 1,4-phenylenebis-1,3,4-oxadiazoles in 35–51% yields. The mass spectra of 2,5-diaryl-1,3,4-oxadiazoles and 1,4-phenylenebis-1,3,4-oxadiazoles were studied. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2309–2316, November, 1998.     

New algorithm and software for analyzing the vibronic spectra of polyatomic molecules

A new algorithm for automatic assignment of the resolved vibrational structure of the electronic absorption spectra of diatomic and polyatomic molecules is suggested. Translated fromZhurnal Struktumoi Khimii, Vol. 38, No. 2, pp. 363–368, March–April, 1997.     

Correcting electronic spectra for distortions caused by inelastic collisions of photoelectrons

A procedure is developed for correcting X-ray photoelectron spectra for distortions caused by inelastic collisions of photoelectrons, leading to an intense tail on the side of higher bond energies. The procedure was used to correct the form of the valence band X-ray photoelectron spectra of pure copper and a Ti-Ni-Cu alloy. Translated fromZhurnal Struktumoi Khimii, Vol. 39, No. 6, pp. 1145–1146, November–December, 1998.     

Pressure effect in the vibronic spectra of perylene inn-Octane

The effect of external pressure on the fluorescence spectra of perylene in n-octane at helium temperatures is investigated. It is shown that isobaric treatment of the sample considerably decreases the electronphonon interaction of the impurity molecules with the surroundings and gives rise to doublet structure of the spectra. The latter is explained in terms of the two-well adiabatic potential model Translated fromZhumal Struktumoi Khimii, Vol. 38, No. 2, pp. 318–323, March–April, 1997.     

X-ray and quantum chemical study of the electronic structure of glycine and its metal complexes

OK_α spectra of glycine and some transition metal complexes with glycine ligands were obtained. The electronic structure of the glycine zwitterion is calculated by a quantum chemical method, and a theoretical X-ray spectrum of the glycine molecule is constructed. The nature of the metal-ligand bond in the compounds is discussed on the basis of experimental spectra and theoretical calculations. Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences. Moscow State Academy of Light Industry, Novosibirsk Branch. Moscow State Academy of Light Industry. Novosibirsk State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 34, No. 4, pp. 112–116, July–August, 1994. Translated by L. Smolina     

Calculation of the vibronic spectra of adenine

The vibrational structure of the absorption spectra of the first two π-π* singlet transitions of adenine is calculated in the Franck-Condon approximation including Herzberg-Teller interactions. The effect of excitation-induced changes in molecular angles on the intensities of the vibrational components is estimated. Structural models of the adenine molecule in the excited states are constructed. The theoretical and absorption spectra of the first π-π* transition are compared. The results of the electronic structure calculations of adenine by different CNDO/S methods are discussed. Translated fromZhumal Struktumoi Khimii, Vol. 38, No. 2, pp. 334–344, March–April, 1997.     

Vibrational spectra of volatile inorganic hydrides in the liquid state

The results of studies of IR and Raman spectra of volatile inorganic hydrides of Group IV–VI and Periods 3 and 4 elements in the liquid state are surveyed and analyzed. The mechanisms of intermolecular interactions in these liquids are discussed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 629–644, April, 1999.     

Electronic structure and spectral characteristics of Bi-Sr-Ca-Cu-O films

The electronic structure of high-temperature superconducting films of Bi-Sr-Ca-Cu-O is determined using the linearized augmented plane wave method. Total and local partial densities of states are calculated for each film using the results of band structure calculations. Theoretical OK_α and CuL_α X-ray emission spectra are found. The dependence of the electronic structure and spectra on the number of CuO₂ layers in the unit cell is discussed. Translated fromZhurnal Strukturnoi Khimii, Vol. 39, No. 6, pp. 1067–1075, November–December, 1998.     

Composition of essential oil from <Emphasis Type="Italic">Artemisia glauca</Emphasis> from western Siberia

The composition of essential oil from Artemisia glauca (Asteraceae) growing in southern Siberia was studied. More than 60 oil components consisting of 99.0–99.7% of the total volatile components were identified by GC—MS by comparison of full mass spectra and retention times. The main components of the essential oil were acetylene derivatives of capillene (11–60%) and benzyldiacetylene (1–31%). Other acetylene derivatives such as capillin, (E)-hex-4-en-2-ynylbenzene, 1-(4-methoxyphenyl)-2,4-pentadiyne, and capillarin were also identified in the oil. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 446–449, September–October, 2007.     

Structure of cycloglobiseposide C fromAstragalus globiceps

A new cycloartane glycoside, cycloglobiseposide C, is isolated from the roots ofAstragalus globiceps Bunge, The structure 3-O-β-D-glucopyranosyl-(1–3)-O-α-L-arabinopyranosyl cycloglobisepogenin is proposed on the basis of NMR spectra. Academician S. Yu. Yunusov Institute of the Chemistry of Plant Substances. Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (99871) 120 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 763–766, November–December, 1999.     

Lavandoside from <Emphasis Type="Italic">Lavandula spica</Emphasis> flowers

The new natural compound lavandoside with the structure ferulic acid 4-O-β-D-glucopyranoside was isolated by column chromatography over silica gel and polyamide from the extract of Lavandula spica flowers. The chemical structure of lavandoside was established using UV, NMR, and mass spectra and chemical transformations. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 133–134, March–April, 2008.     

Structure of cyclochivinoside C from <Emphasis Type="Italic">Astragalus chivensis</Emphasis>

The new cycloartane glycoside cyclochivinoside C, 24S-cycloartan-3β,6α,16β,24,25-pentaol 3,16-di-O-β-D-glucopyranoside, was isolated from the aerial part of Astragalus chivensis. The structures of the isolated compounds were established by chemical transformations and PMR and ¹³C NMR spectra. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 460–462, September–October, 2007.     

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     

Structure of mucroflavone A

A new flavonoid, mucroflavone A, is isolated from the terrestrial part ofTanacetopsis mucronata (Regel. et Schmalh.) S. Kovalevsk. IR, mass, UV, and PMR spectra are compared with those of related compounds to provide a basis for proposing the structure 5,6,4′-trihydroxy-8,3′-dimethoxyflavone for mucroflavone A. Deceased. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 725–729, November–December, 1999.     

Quantitative prediction of absorption maxima in the electronic spectra of unsaturated compounds: Extrapolation from fragments to molecules in quantum chemical calculations

The possibility of quantitative prediction of maxima in the electronic absorption spectra of unsaturated organic compounds is studied by the Pariser-Parr-Pople method with fitted parameters. The quantum chemical methods are classified according to the type of extrapolation: from elementary particles (physical constants) to molecules, from atoms to molecules, and from fragments to molecules. N. G. Chernyshevskii Saratov State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 6, pp. 1016–1022, November–December, 1996. Translated by I. Izvekova