Synthese,Kristallstruktur und spektroskopische Charakterisierung von Tetraphosphorhexaoxid-monoselenid,P4O6Se

Synthesis, Crystal Structure, and Spectroscopic Characterization of Tetraphosphorus Hexaoxide Monoselenide, P₄O₆Se P₄O₆Se has been synthesized by photochemical reaction between P₄O₆ and elemental selenium in CS₂ in presence of iodine as a catalyst. Single crystals form at purification via sublimation. The compound (m. p. 46°C) crystallizes in the monoclinic space group P2₁/c (no. 14) with a = 1 051.8(2), b = 652.9(1), c = 1 178.6(2) pm, β = 109.29(1)°, Z = 4. Within the limits of experimental error, the molecules exhibit C_3v symmetry. IR, Raman, and ³¹P n.m.r. (solution) spectra of the compound are reported and discussed. The geometry of the Molecule as determined by theoretical methods (SCF level) is in good agreement with the experimental results.     

Tetrakis(2-fluorophenylamino)silan und sein erstes Kondensationsprodukt N-(2-fluorophenyl)-Si,Si, Si,Si′, Si′, Si′-hexakis(2-fluorophenylamino)-disilazan. Synthesen und Kristallstrukturen

Zusammenfassung Tetrakis(2-fluorophenylamino)silan (1) wurde als Precursor zur Darstellung poröser, nitridischer Festkörper synthetisiert und mit Hilfe der Einkristallröntgenstrukturanalyse charakterisiert (C2/c;a=16.771(7) Å,b=16.827(5) Å,c=16.753(6) Å, ß=111.00(2)°,z=8). Beim Erhitzen mit Ammoniumcarbamat als Katalysator wurde N-(2-fluorophenyl)-Si, Si, Si, Si, Si, Si, -hexakis(2-fluorophenylamino)disilazan (2) als erstes Kondensationsprodukt isoliert ( ;a=9.331(1) Å,b=13.698(5) Å,c=16.164(4) Å, =90.34(2)°, ß=103.03(2), =103.04(3)°, Z=2).

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Tetrakis(2-fluorophenylamino)silane and its first product of condensation N-(2-fluorophenyl-Si, Si, Si, Si, Si, Si-hexakis(2-fluorophenylamino)disilazane. Syntheses and crystal structures

Summary The synthesis and crystal structure determination of silanetetramine N,N,N,N2-fluorophenyl(C2/c;a=16.771(7) Å,b=16.827(5) Å,c=16.753(6) Å, ß=111.00(2)°, z=8) are reported. In a search for suitable condensation pathways to silicon/nitrogen based porous solids, N-(2-fluorophenyl)-Si,Si,Si,Si,Si,Si-hexakis(2-fluorophenylamino)disilazane (2) has been obtained from the ammonium carbamate catalyzed condensation of the silanetetramine in teflon lined autoclaves. The X-ray crystal structure determination ( ;a=9.331(1) Å,b=13.698(5) Å,c=16.164(4) Å, =90.34(2)°, ß=103.03(2)°, =103.04(3)°, Z=2) shows the disilazane to be a dimer formed by linear condensation from the monomeric silazane.

     

Synthesis,Crystal Structure Determination,and Physical Properties of Ag5IO6

The silver iodate(VII), Ag₅IO₆, was obtained by reacting a stoichiometric mixture of Ag₂O and KIO₃, at elevated oxygen pressure, adding a small portion of distilled water. The synthesis was done at 673 K and 270 MPa of oxygen pressure. The crystal structure was solved by direct methods based on single crystal diffraction data ( , Z = 6, a = 5.9366(1), c = 32.1471(6) Å, 323 independent reflections, R₁ = 2.31 %). According to conductivity measurements, Ag₅IO₆ is semiconducting with a specific resistance of 0.08 Ωcm at 300 K. The activation energy was determined as 7.4(1) meV in the temperature range of 220 – 300 K, and 4.3(1) meV in the temperature range of 90 – 180 K. The optical band gap for Ag₅IO₆ is 1.4 eV. Ag₅IO₆ is diamagnetic with a magnetic susceptibility of ?4.4×10^?4 emu/mol.     

Profiling of plasma cholesterol ester and triglyceride fatty acids as their methyl esters by capillary gas chromatography, preceded by a rapid aminopropyl-silica column chromatographic separation of lipid classes

A rapid procedure for the isolation of plasma cholesterol ester and triglyceride fractions with aminopropyl-silica columns, followed by analysis of their fatty acid compositions by capillary gas chromatography with flame ionization detection, is described. Within-series and long-term (six months) series-to-series precision were investigated. The isolation procedure caused minimal cross-over between the two lipid classes. Reference values for 57 apparently healthy Dutch adults were established and compared with data reported from other countries. Feeding of rats with four diets differing in their fatty acid compositions showed the relationship between the composition of the fatty acids in the diet and those esterified to cholesterol in plasma. The method is of potential usefulness to the establishment of the compliance of dietary interventions and basic dietary experiments.     

(PPh4)2[MoN(N3)3Cl]2; Synthese,IR-Spektrum und Kristallstruktur

(PPh₄)₂[MoN(N₃)₃Cl]₂; Synthesis, IR Spectrum, and Crystal Structure The title compound is formed in the reaction of molybdenum (II) benzoate with trimethylsilyl azide and PPh₄Cl in dichloro methane forming dark red single crystals. A PPh₃Me⊕ salt of the ion [MoN(N₃)₃Cl]₂^2? is obtained from (PPh₃Me)₂MoNCl₄] treated with silver azide in CH₂Cl₂ suspension. The solvent CH₂Cl₂ participates in both reactions as oxidizing agent. (PPh₄)₂[MoN(N₃)₃Cl₂ is characterized by a structural analysis based upon X-ray data: space group P1 , Z = 1, a = 1050.7 pm; b = 1185.4 pm; c = 1190.8 pm; α = 98.90°; β = 106.87°; γ = 103.97° (4505 independent, observed reflexions, R = 0.039). The compound consists of PPh₄⊕ cations and centrosymmetric anions [MoN(N₃)₃Cl₂^2? in which the molybdenum atoms are bridged by the N_α atoms of two azide groups; the resulting Mo? N bond lengths are 208 pm and 260 pm. In trans position to the long Mo? N bond the terminal nitrido ligand is situated, the Mo?N distance of 164 pm corresponds to a triple bond. Two terminal azido ligands and the chloro ligand are filling up the coordination sphere of the molybdenum atoms to a coordination number of six. The i.r. spectrum is reported and assigned.     

Relativistic all-electron configuration interaction calculations on the gold atom

We present the results of relativistic and non-relativistic self-consistent field and configuration interaction calculations for the gold atom, using the spin-free no-pair Hamiltonian in a basis set expansion. A new basis set for the gold atom is discussed and its results in relativistic and non-relativistic self-consistent field calculations are compared to those of numerical Dirac-Hartree-Focic and Hartree-Fock calculations, respectively. Excitation energies, electron affinities and ionization potentials were calculated using a multi-reference configuration interaction technique and are in reasonable agreement with experiment in the relativistic case.     

Synthesis and properties of phenyl benzoate-based and biphenyl-based liquid crystalline thiol-ene monomers

Novel phenyl benzoate-based and biphenyl-based liquid crystalline thiol-ene monomers were synthesized and their properties investigated. By varying the bridging unit and spacer length, the type of mesophase can be tuned from the low ordered nematic and smectic A phase in the case of the phenyl benzoate-based monomers, to the highly ordered crystal E phase for the biphenyl-based monomers and their corresponding bromo precursors. We investigated the degree of order of the phenyl benzoate-based materials using the Haller method. Possible premature polymerization of these monomers was examined by size exclusion chromatography. The materials exhibit low transition temperatures and a high stability at typical handling times and temperatures. Consequently, these monomers are useful for in situ polymerization with anisotropic inert solvents, which could potentially lead to new architectures and enhanced electro-optical properties of devices. The use of the biphenyl-based monomers appears to be of limited use for polymerizations in anisotropic solution. However, as a result of their intrinsic high degree of molecular order, these monomers form a particularly interesting class of reactive materials that can be bulk polymerized to give main chain polymers with highly defined mechanical and optical or electro-optical properties.     

[Mo12O40P][C44H38P2][CoC10H10] * 3(C3H7NO): A quasi-ternary intercluster compound

Binary intercluster compounds (IC) can be reduced to basic structure types of ionic solids. We examined the validity of this concept for ternary compounds, on the example of a quasi-ternary intercluster compound made from a Keggin anion ([PMo₁₂O₄₀]^3?), an organic cation (o-xylylenebis(triphenylphosphonium)), and a complex (cobaltocenium). The new compound and its two related quasi-binary IC were investigated by X-ray diffractometry, examined for intermolecular interactions such as hydrogen-bonding, π–, or van der Waals-interactions, and evaluated for possible reductions to basic structure types.