Isotropic C6, C8 and C10 interaction coefficients for CH4, C2H6, C3H8, n-C4H10 and cyclo-C3H6

The non-empirical generalized Kirkwood, Unsöld, and the single-Δ Unsöld methods (with double-zeta quality SCF wave-functions) are used to calculate isotropic dispersion (and induction) energy coefficients C_2n, with n ? 5, for interactions involving ground state CH₄, C₂H₆, C₃H₈, n-C₄H₁₀ and cyclo-C₃H₆. Results are also given for the related multipole polarizabilities α_l, multipole sums S₁/(0) and S₁(?1) which are evaluated using sum rules, and the permanent multipole moments. for l = 1 (dipole) to l = 3 (octupole). Estimates of the reliability of the non-empirical methods, for the type of molecules considered, are obtained by a comparison with accurate literature values of α₁S₁(?1) and C₆. This, and the asymptotic properties of the multipolar expansion of the dispersion energy, the use to discuss recommended representation for the isotropic long range interaction energies through R^?10 where R is the intermolecular separation.     

Ionization efficiencies of C3H6, C4H8, C6H12, C2H6O,and C3H8O isomers

Ionization efficiencies of 14 organic compounds have been measured in the wavelength region from 105 to 134nm using an ionization chamber. The compounds examined are cyclopropane, propylene, l-butene, isobutene, cis-and trans-2-butenes, cyclohexane, 1-hexane, tetramethylethylene, ethyl alcohol, dimethyl ether, n-, and iso-propyl alcohol, and ethyl methyl ether. The ionization efficiencies of cyclopropane and cyclohexane monotonically increase with increasing photon energy, but those for the others show a peak or a shoulder in the wavelength region of the present work.     

Die Trennung von 4 Phenolen und 6 aliphatischen Alkoholen

Ohne Zusammenfassung     

Die Trennung von Ar und O2 sowie CH4, C2H6, C3H8 und C4H10

Ohne Zusammenfassung     

Aryl- und Arin-Komplexe von Übergangsmetallen der sechsten Gruppe Darstellung von [Mo(p-C6H4CH3)6(Li · OC4H10)3] und [W(p-C6H4CH3)4(C6H3CH3)2(Li · OC4H10)4] sowie NMR-spektroskopische Untersuchung des W-Komplexes

Aryl and Aryne Complexes of Group Six Transition Metals. Preparation of [Mo(p-C₆H₄CH₃)₆(Li · OC₄H₁₀)₃] und [W(p-C₆H₄CH₃)₄(C₆H₃CH₃)₂(Li · OC₄H₁₀)₄] and NMR Spectroscopic Investigation of the W Complex Molybdenum(V) chloride reacts with an etheral solution of p-tolyllithium (molar ratio 1:10) to yield a yellow, strongly paramagnetic hexatolylo complex ([MoTol₆(Li · S)₃]¹) (μ_eff = 3.51 B.M.), while from tungsten(V) bromide and p-tolyllithium (molar ratio 1:11) a blackish violet, diamagnetic complex [WTol₄Tn₂(Li · S)₄] is formed, containing two tolylene or tolyne groups for ligands. The ¹H-NMR spectrum points to the Tol-ligands being influenced by the methyl groups of the Tn-ligands.     

Die Trennung von Chlorophyll a und b sowie ihrer Abbauprodukte

Ohne Zusammenfassung     

Die Trennung von Catecholaminen und Meta- sowie Normetanephrin durch Austauschchromatographie

Ohne Zusammenfassung     

Synthese und Röntgenstrukturanalyse des 8π-Elektronenringsystems S4N4O2Sn2(CH3)6 und des magnetische Verhalten von S4N4O2 und S8N8O4

Synthesis and X-Ray Structure Analysis of the 8π-Electron-Ring-System S₄N₄O₂Sn₂(CH₃)₆ and the Magnetic Properties of S₄N₄O₂ and S₈N₈O₄ S₄N₄O₂ reacts with N[Sn(CH₃)₃]₃ in a molar ratio of 1:1 to an eight-membered trimethyltin-substituted 8π-electron skeleton, S₄N₄O₂Sn₂(CH₃)₆. In contrast to known 6π-electronsystems this compound has tin atoms which are tetracoordinated. This was demonstrated on the basis of an x-ray analysis. S₄N₄O₂Sn₂(CH₃)₆ · 1/2 C₆H₆ crystallizes in the space group P2₁/c with a = 1396.0(4), b = 1190.3(4), c = 1256.7(3) pm, and β = 103.46(2)°. It was shown that the ability of coordination at the tin atom depends on the electron density. The magnetic properties of S₄N₄O₂ and S₈N₈O₄ were investigated by the Faraday method. The high diamagnetism in these ring compounds is caused by the π-electrons.     

Diskussion Intramolekularer Wechselwirkungen an RC6H4(CH3)2SiF-, RC6H4(CH3)2SiOCH3-, RC6H4O(CH3)2SiF-, RC6H4OSi(CH3)3- und (CH3)3MF- [M  C,Si, Ge,Sn] Verbindungen

Chalcogenide Glasses with Organic Components. I. Glasses of the Selenium-Arsenic-Bromine-Azobenzene System New glasses were prepared by melting suitable glasses of the system Se? As? Br and of Bis(selenenylbromido)-azobenzene, and cooling them subsequently. Azobenzene groups are connected with the inorganic glass by selenium-carbon bonds. These substances represent the link between polymers as part of the organic chemistry and inorganic glasses. The structures of these products are discussed on the basis of thermal, conductivity, and infrared spectroscopic studies and of density measurements.     

Darstellung und Kristallstruktur von (CH3NH3)8[NdCl6][NdCl4(H2O)2]2Cl3

Preparation and Crystal Structure of (CH₃NH₃)₈[NdCl₆][NdCl₄(H₂0)₂]₂Cl₃ (CH₃NH₃)₈[NdCl₆][NdCl₄ (H₂O)₂]₂Cl₃ is for the first time prepared and investigated by X-ray, single crystal work. It crystallizes in the monoclinic system (space group C2/m, Z = 2) with a = 9.358(5), b = 17.424(9), c = 15.360(8) Å, β = 108.30(4)°. The structure contains besides isolated Cl^? ions distorted [NdCl₆]^3? octahedra and [NdCl₄(H₂O)₂]^? chains.     

Gas-chromatographische Simultanbestimmung von O2, N2, CO,CO2, N2O,SO2, CH4, C2H4 und C2H6 im ppm-Bereich. I. Mitteilung

Zusammenfassung Die vorliegende Arbeit beschreibt ein neues Verfahren zur gas-chromatographischen Simultananalyse von N₂, O₂, CO, CO₂, N₂O, SO₂, CH₄, C₂H₄ und C₂H₆ im Konzentrations-bereich von 10% bis 10 ppm ohne Voranreicherung. Die temperaturprogrammierte Trennung der Einzelkomponenten erfolgt nach Vorsäulensplitting auf zwei parallel geschalteten Säulen. Zur Emittlung der Retentionszeiten und der Peakflächen werden zwei voneinander unabhängige Ultraschalldetektoren verwendet, deren Analogsignale nach Digitalisierung in einem Mikrocomputer verarbeitet werden. Instrumentierung und chromatographische Einzelheiten werden beschrieben und diskutiert.

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Simultaneous gas chromatographic determination of N₂, O₂, CO, CO₂, N₂O, SO₂, CH₄, C₂H₄ and C₂H₆ at the ppm-level. Part I

Summary A new procedure for the simultaneous determination of N₂, O₂, CO, CO₂, N₂O, SO₂, CH₄, C₂H₄ and C₂H₆ by gas chromatography is described. Concentrations from 10% down to 10 ppm can be determined without preconcentration. After a pre-column splitting the individual compounds of the sample are separated by a uniform temperature program on two different columns in parallel. Detection of the effluents is achieved by two individual ultrasonic detectors, the data from which are processed in a micro-computer. Instrumentation and gas chromatographic details are described and discussed.

     

Die IR-Spektren von NH4UO2AsO4·3H2O und NH4UO2PO4·3H2O

The infrared spectra of the title compounds, as well as that of the structurally related mineral meta-autunite, [Ca(UO₂)₂(PO₄)₂·n H₂O], are reported and discussed using the available crystallographic data. The results can be considered as representative for the full group of the so-called torbernite-minerals.     

Die gaschromatographische Trennung von 2- und 3-Alkylpyrrolen

Ohne Zusammenfassung     

Total cross sections for electron scattering by polyatomic molecules at 10–1000 eV: C2H2, C2H4, C2H6, C3H6, C3H8 and C4H8

A model complex optical potential (composed of static, exchange, polarization and absorption terms) is employed to calculate the total (elastic and inelastic) electron-atom scattering cross sections from the corresponding atomic wave function at the Hartree-Fock level. The total cross sections (TCS) for electron scattering by their corresponding molecules (C₂H₂, C₂H₄, C₂H₆, C₃H₆, C₃H₈ and C₄H₈) are firstly obtained by the use of the additivity rule over an incident energy range of 10–1000 eV. The qualitative molecular results are compared with experimental data and other calculations wherever available, good agreement is obtained in intermediate-and high-energy region.     

Die Kristallstrukturen von Mn5O8 und Cd2Mn3O8

The crystal structures of Mn₅O₈ and Cd₂Mn₃O₈ are determined from single crystal and high resolution X-ray powder data. Both structures have very similar monoclinic unit cells, space group C–C2/m, and are isotypic: Hence, the true formula of Mn₅O₈ is MnMnO₈. The crystal structure consists of pseudohexagonal Mn^IV sheets (bc) with similar oxygen sheets on either side, giving a distorted octahedral coordination to the Mn^IV. As every fourth Mn^IV is missing in these “main layers”, their composition becomes Mn₃O₈, and chains of coordination octahedra linked by common edges become distinct. Above and below the empty Mn^IV sites are either Mn^II or Cd^II completing the composition MnMnO₈ or Cd₂Mn₃O₈ respectively. Examples of similar “double layer” structures are given.     

Untersuchungen zu Synthese und Reaktionen von Fluorphenylquecksilber-Derivaten mit den Liganden 2-FC6H4, 2,6-F2C6H3 und 2,4,6-F3C6H2

Investigations on Syntheses and Reactions of Fluorophenylmercury Compounds with the Ligands 2-FC₆H₄, 2,6-F₂C₆H₃, and 2,4,6-F₃C₆H₂ 2,6-F₂C₆H₃HgCl and 2,4,6-F₃C₆H₂HgCl are synthesized via the reactions of the corresponding phenylmagnesium compounds and HgCl₂. 2-FC₆H₄HgCl is selectively obtained only in a reaction involving intermediately formed Cd(2-FC₆H₄)₂. The diphenylmercury derivative Hg(2,4,6-F₃C₆H₂)₂ is obtained while stirring a dichloromethane solution of 2,4,6-F₃C₆H₂HgCl for several days. The direct mercuration of 1,3,5-trifluorobenzene with Hg(OCOCF₃)₂ yields, depending on the stoichiometry, 2,4,6-trifluorophenylmercury trifluoroacetate and 1,3-bis(trifluoroacetatomercuri)-2,4,6-trifluorobenzene which is converted into the corresponding chloromercuri derivative by treatment with hydrochloric acid in CH₃CN. As a product of the reaction of 1,3,5-trifluorobenzene and HgO in CH₃COOH only 2,4,6-trifluorophenylmercury acetate is isolated although spectroscopic evidence has been found for double and triple mercurated derivatives. All compounds are characterized by elemental analyses, nmr and mass spectra. The reaction of Hg(2,4,6-F₃C₆H₂)Cl and Cd(CF₃)₂ · 2 CH₃CN gives Hg(2,4,6-F₃C₆H₂)CF₃ which slowly dismutates in CH₂Cl₂ solution into Hg(2,4,6-F₃C₆H₂)₂ and Hg(CF₃)₂. The ligand exchange of Hg(2,4,6-F₃C₆H₂)₂ and TeCl₄ selectively gives Te(2,4,6-F₃C₆H₂)₂Cl₂ and Hg(2,4,6-F₃C₆H₂)Cl. Transmetalations of Hg(2,4,6-F₃C₆H₂)₂ and gallium or tin give NMR spectroscopic evidence for the new derivates Ga(2,4,6-F₃C₆H₂)₃ and Sn(2,4,6-F₃C₆H₂)₄.     

Unimolekulare CH3-, CH4-, C2H4- und C3H4-Eliminierungen aus alkin- und arylsubstituierten Isopropylkationen in der Gasphase

Elimination of methyl, methane, ethylene, allene (or propyne) from two [C₃H₆Y]+ isomers (Y = p-(HC?C)? C₆H₄- and C₆H₅? C?C?) has been investigated using 13C and deuterium labelled compounds. It can be shown that the fragmentations are accompanied by extensive but not complete rearrangement of the carbon skeleton as well as by migration of the hydrogen atoms, the extent of which is determined by the reaction channel.     

Kristallstrukturen von Säurehydraten und Oxoniumsalzen. XX. Die Oxoniumtetrafluoroborate H3OBF4, [H5O2]BF4 und [H(CH3OH)2]BF4

Crystal Structures of Acid Hydrates and Oxonium Salts. XX. Oxonium Tetrafluoroborates H₃OBF₄, [H₅O₂]BF₄, and [H(CH₃OH)₂]BF₄ The crystal structures of three oxonium tetrafluoroborates were determined. H₃OBF₄, oxonium tetrafluoroborate proper, is triclinic with space group P1 , Z = 2 and the unit cell dimensions a = 4.758, b = 6.047, c = 6.352 Å and α = 80.40, β = 79.48, γ = 88.25° at ?26°C. Cations H₃O⁺ and anions BF₄^? are linked by hydrogen bonds O? H…?F into ribbons of condensed rings. In [H₅O₂]BF₄ (diaquohydrogen tetrafluoroborate, monoclinic, P2₁/c, Z = 4, a = 6.584, b = 9.725, c = 7.084 Å, β = 95.15° at ?100°C) the hydrogen bond in the cation H₅O₂⁺ is 2.412 Å short, asymmetric and approximately centered and the linking of cations and anions three-dimensional. In [H(CH₃OH)₂]BF₄ (Bis(methanol)hydrogen tetrafluoroborate, monoclinic, P2₁/c, Z = 4, a = 5.197, b = 14.458, c = 9.318 Å, β = 94.61° at ?50°C) the cation [H(CH₃OH)₂]⁺ is characterized for the first time in a crystal structure with an again very short (2.394 Å), asymmetric and effectively centered hydrogen bond. By further hydrogen bonds cations and anions form only dimers of the formula unit of centrosymmetric cyclic structure.