bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Dielectric Relaxation of Water on Addition of Ethylene Carbonate and some Related Substances
Authors: Stockhausen M. , Lux A. 
Published: February 2015

Abstract
The dynamic dielectric properties of diluted aqueous solutions of propylene carbonate, ethylene carbonate (EC). 4-butyrolactone and cyclohexanone (CH) have been measured at 20 °C. On assuming normal solute relaxation, the water relaxation can be described by two superimposed Debye type contributions, which may be interpreted in terms of a hydration model. Qualitatively, the influence on the water relaxation increases from EC to CH.
Structure Calculations on 1,3,4-Thiadiazole with Computer Programs
Authors: Stiefvater Otto L. , Rudolph H. D. 
Published: February 2015

Abstract
Insertion of the 14 available sets of isotopic moments of 1,3,4-thiadiazole into the computer programs GEOM or RU 111/115 confirms the previously hand-calculated structure parameters of this molecule, but does not further improve the accuracy of those results.
A Study of Anonic Motions in Solid Rubidiumand Cesium Tetrachloroaurates(III)by Measuring the Temperature Dependence of Chlorine Nuclear Quadrupolar Relaxation Times
Authors: Ishikawa Atsushi , Asaji Tetsuo , Nakamura Daiyu , Ikeda Ryuichi 
Published: February 2015

Abstract
The temperature dependences of 35Cl NQR frequencies and 35Cl nuclear quadrupolar relaxation times T1Q and T2Q were determined above 82K for Rb[AuCl4] and CsfAuClJ up to ca. 340 and 320 K, respectively. Below these temperatures two 35Cl NQR frequencies were observed for each complex whereas no resonance could be detected above the respective temperatures. For both complexes, T1Q observed below ca. 270 K was interpreted as mainly determined by the rotary lattice vibration around the pseudo-C4(C4) axis and each Cl-Au-Cl diagonal axis of the square planar complex anion, whereas T1q observed above ca. 270 K was definitely shown to be determined through the reorientation of the anions about their C′4 axis. The activation energies for the C′4 reorientation of the anions was evaluated to be 71 and 53 kJ mol-1 for the rubidium and cesium salts, respectively. The anionic dynamics are discussed by assuming the motion of the anions within and out of the C4 potential wells at lower and higher temperatures, respectively.
FT-IR Absorption Spectra of Polycrystalline Pressed Sample soft he Organic Metals and Superconductorsa α-β-(BEDT-TTF)2I3 and(BEDT-TTF)2Cu(NCS)2
Authors: Zamboni R. , Schweitzer D. , Keller H. J. , Taliani C. 
Published: February 2015

Abstract
IR absorption spectra of polycrystalline pressed samples of the organic metals α-(BEDT-TTF)2I3, β-BEDT-TTF)2I3 and (BEDT-TTF)2Cu(NCS)2 are presented and discussed. Normal protonated as well as deuterated materials were studied. The spectra range from 400 cm-1 to 5000 cm-1 and are similar to the IR reflectance spectra reported ealier. The data are of special interest in view of the fact that recently bulk superconductivity was observed in such polycrystalline samples of organic metals, and therefore the application of organic superconductors for the preparation of electronic devices seems possible.
New Evidence for Symmetry Dependent Isotope Effects: O+CO Reaction
Authors: Bhattacharya S. K. , Thiemens M. H. 
Published: February 2015

The isotopic fractionation associated with the O + CO reaction has been studied using oxygen atoms produced by room temperature O2 photolysis at two different wavelengths, 185 and 130 nm. A large mass-independent isotopic fractionation is observed in the product CO2, extending the range of this type of reaction beyond O + O2 and SF5 + SF5.
Kinetic evaluation of the data restricts the source of the mass-independent fractionation mechanism to the O + CO recombination step rather than O2 photolysis, secondary ozone formation, or O2 photodissociation. At least one, and most likely two other fractionation processes appear to occur in the experiments, and interpretation of the isotopic results is tentative at present. Based on the relevant reaction rates and the value for the reduced partition function for isotopic exchange between O and CO, it is suggested that this process may occur prior to the δ17O≅δ18O recombination process. Secondary CO2 photolysis may superimpose an additional fractionation. The experimental data are also examined in the context of a model based upon energy randomization rates versus the lifetime of the activated complex.
Proton Spin Relaxation in Reentrant Nematic Cyano -biphenyl Liquid Crystals
Authors: Schweikert K. H. , Noack F. 
Published: February 2015

Abstract
The frequency dependence of the longitudinal proton spin relaxation time T1 was measured by field-cycling and standard NMR techniques in the nematic, smectic and reentrant nematic mesophases of the reentrant liquid crystal 6OCB-8OCB. The results clearly demonstrate that, in contrast to conclusions reported in the literature, the underlying relaxation mechanisms are the same for the nematic and reentrant nematic order, but different in the nematic and smectic phase. In particular, at low frequencies the nematic and reentrant samples reveal a square-root dispersion profile (T1,~ ν½) characteristic for nematic director fluctuations, whereas the smectic samples show a dissimilar and only very narrow dispersion step. It can be attributed to a linear relaxation time increase (T1 ~ v1) expected for smectic-type order fluctuations. The experimental data are described and discussed in terms of four molecular processes, namely nematic or smectic order fluctuations, self-diffusion, rotational motions, and a resonant proton nitrogen coupling.
Ferroelektrische Flüssigkristall - Mischungen mit Kohlenhydrat - Derivaten als Dotierstoffe / Ferroelectric Liquid Crystal Mixtures with Carbohydrate Derivates as Dopants
Authors: Vill V. , Fischer F. , Thiem J. 
Published: February 2015

Abstract
For the first time carbohydrate derivatives were studied as dopants for calamitic smectic phases. Fast switching ferroelectric cells could be realized, and electroclinic effects were observed. By inversion of configuration at a chiral center of these compounds switching times, solubility, and helical twisting power vary by orders of magnitude. The studied derivatives showed modest solubility properties.
Hydrogen in Electrodynamics. IV. The Components of the Hydrogen Field
Authors: Sallhofer Hans 
Published: February 2015

Abstract
After a discussion of the one-component Schrödinger (1926) and the four-component Dirac (1928) representation of hydrogen it is shown that the six-component electrodynamic picture turns out to be considerably simpler and clearer. The computational effort is reduced to a fraction.
Self-Diffusion and Reorientation of Methylammonium Ions in (CH3NH3)2ZnCl4 Crystals as Studied by 1H-NMR
Authors: Ishida Hiroyuki , Iwachido Tadashi , Hayama Naomi , Ikeda Ryuichi , Terashima Mifune , Nakamura Daiyu 
Published: February 2015

Abstract
Differential thermal analysis, differential scanning calorimetry, and measurements of the 1H spin-lattice relaxation times and second moments of 1H-NMR absorptions were performed on methylammonium tetrachlorozincate (II) crystals over a wide temperature range. A solid-solid phase transition was located at 477 K. From the 1H-NMR experiments it was found that the cations undergo overall reorientation as well as three dimensional translational self-diffusion in the high-temperature phase. In the low-temperature phase, a 120° reorientational motion of the CH3 and NH3
+ groups of the cation about its C-N bond axis was detected. The parameters for the motional modes of the cations in the crystal were evaluated from the analysis of the 1H-NMR experimental results.
Pars Orbital Method for Excited States
Authors: Polansky Oskar E. , Fabian Walter M. F. 
Published: February 2015

Abstract
Based on a projection operator formalism the pars orbital method is reformulated for the general case that both the molecule M as well as the reference molecule L-are described by a CI-expansion of the wave function. Some numerical examples in which the method is used for the interpretation of the ultraviolet spectra of simple organic molecules (butadiene, aniline, benzonitrile, o-, m-, and p-aminobenzonitrile, 2,5-diamino-p-benzoquinone) in terms of the various states (ground as well as excited) of the respective reference molecules are discussed in some detail to illustrate the scope and limitations of the proposed formalism. The results of these calculations are in addition compared to results obtained by two other methods (configuration analysis and specific measures of partial distances) designed to allow an analysis of molecules in terms of the constituent fragments.
Labile Trace Elements in Some Antarctic Carbonaceous Chondrites: Antarctic and Non-Antarctic Meteorite Comparisons
Authors: Paul Rick L. , Lipschutz Michael E. 
Published: February 2015

Abstract
We report data for Ag, Au, Bi, Cd, Co, Cs, Ga, In, Rb, Sb, Se, Te, TI, U and Zn determined by radiochemical neutron activation analysis in consortium samples of Belgica (B) 7904, Yamato (Y) 82042, Yamato 82162 and Yamato 86720 carbonaceous chondrites. These trace elements cover a wide volatility/mobility range and give unique information on thermal histories of meteorites. The results indicate the unique nature of these carbonaceous chondrites. Y-82042 proves to have the volatile element pattern of a C2 ( ≡CM) chondrite and the petrologic characteristics of a CI (n≡CI) chondrite. These must be primary nebular condensation/accretion features, unaffected by post-accretionary processes. The other three meteorites were thermally metamorphosed in ≧2 parent regions over the 600-700 °C range, at relative temperatures B-7904 < Y-82162< Y-86720. Before heating, B-7904 and Y-86720 had C2-levels of volatile elements: Y-82162 had uniquely high volatile element concentrations, at about CI-levels. The data require a new classification scheme for such chondrites. Belgica 7904 and Y-82162 and -86720 seem to be derived from one or more thermally altered carbonaceous asteroids, and their spectral characteristics should be compared with those of B-, F-, G- or T-asteroids. These results indicate substantial differences in the thermal histories of Antarctic and non-Antarctic CI and C2 chondrite populations. In reviewing all that is known about the Antarctic and non-Antarctic meteorite populations, the overwhelming weight of evidence supports the view that these populations sample different extraterrestrial source materials, differing in thermal histories. It may be that over the extended collecting period of the Antarctic ice sheet, it has sampled a considerably greater proportion of near-Earth asteroids than do current falls.
Chemical Composition of an Unusual Xenolith of the Allende Meteorite
Authors: Palme H. , Kurat G. , Spettel B. , Burghele A. 
Published: February 2015

Abstract
The chemical composition of an unusual xenolith (All-AF) from the Allende meteorite was determined by neutron activation and x-ray fluorescence analyses. The xenolith is similar in bulk composition to Allende, but has large excesses in some moderately volatile trace elements, such as Na, K, Au, Sb etc. Some of these elements show considerable variations in other components of Allende, suggesting inhomogeneous distribution in Allende. However, elements of higher volatility, such as Zn and Se have concentrations typical of bulk Allende and other type 3 carbonaceous chondrites. Therefore, All-AF must have formed from the same reservoir as bulk Allende.
All-AF has uniform grain size and does not, and did never, contain chondrules. The low content of volatile elements, therefore cannot be ascribed to loss of volatiles during the chondrule forming process. It is a characteristic of the Allende reservoir. The chemical composition of related dark inclusions (DIs) in Allende is different from All-AF. Dark inclusions may have formed by separation of fine grained material in the early solar nebula while All-AF resembles bulk Allende material that was never subject to chondrule formation. Both, dark inclusions and All-AF have oxygen isotopic compositions which plot at the upper end of the δ18O vs. δ17O correlation, suggesting extensive oxygen exchange with ambient gas.
Resonance Transition of the Spatial Correlation Factor of Self-Generated Oscillations in the Postbreakdown Regime of p-Ge
Authors: Schöll E. , Naber H. , Parisi J. , Röhricht B. , Peinke J. , Uba S. 
Published: February 2015

Abstract
The linear correlation factor of spatially coupled nonlinear self-generated oscillations in the post-breakdown regime of p-Gc at 4.2 K is investigated. The observed results can be consistently explained in terms of a two-cell model of energy relaxation oscillations, which yields resonance transitions between correlated and anticorrelated oscillations. These are due to node-focus transitions of the fixed point of the passive cell which is slaved by the active cell.
The Microwave Spectrum and Nuclear Quadrupole Coupling Constants of HNC17O
Authors: Gerry M. C. L , Howard S. J. , Heineking N. , Dreizler H. 
Published: February 2015

Abstract
The microwave spectrum of HNC17O is reported for the first time. The measurements were made with both Stark modulated and microwave Fourier transform spectrometers. The 17O and 14N quadrupole hyperfine structure has been resolved and rotational, centrifugal distortion and 17O and 14N quadrupole coupling constants have been evaluated. The 17O coupling constants are compared with those from an ab initio prediction.
Atomic Structure of Amorphous Fe-Tb-and Amorphous Fe-Co-Tb-Alloys by Means of EDXD
Authors: Utz R. , Brunsch A. , Lamparter P. , Steeb S. 
Published: February 2015

Abstract
We present structural investigations using the energy dispersive X-ray diffraction (EDXD)- method on amorphous Fe-Tb- and Fe-Co-Tb-alloys over an extended concentration range. Atomicdistances. partial coordination numbers, and chemical short range order parameters are reported. The short range order is characterized by a compound forming tendency. In an amorphous Fe-Co- Tb-alloy, doping with hydrogen affects the short range order and gives rise to an in-plane magnetization direction.
Studies on Molecular Motionsand Phase Transition in Pyridinium Tetrachloroiodate(III)Crystals by the Measurements of the Temperature Dependences of Chlorine Nuclear Quadrupole. Resonance Frequencies and Relaxation Times
Authors: Ishikawa Atsushi , Asaji Tetsuo , Nakamura Daiyu 
Published: February 2015

Abstract
To elucidate the phase transition of pyridinium tetrachloroiodate(III) at Tc = 217 K, the temperature dependences of the chlorine NQR frequencies and corresponding NQR spin-lattice and spin-spin relaxation times (T1Q and T2Q) have been measured in the range 77-370 K. Above ca. 370 K and between 206 and 223 K no chlorine NQR frequency could be observed, the chlorine relaxation times becoming extremely short (ca. 100 μs). Except for near Tc, the T1Q values below ca. 310 K can be explained by fluctuations of the electric field gradient at the chlorine nuclei due to in-plane reorientations of the cations about their pseudohexad axis. The increase of T1q
-1 in the vicinity of Tc suggests a critical slowing down of the orientational fluctuations of the cations and a distortion of the complex anions. The decrease of T1Q above 310 K is considered to be mainly due to the in-plane reorientation of the complex anions. An activation energy of 64 kJ mol-1 is evaluated for that motion.
3.5-Di-tert-butylstyrole: Synthese sterisch anspruchsvoller Polymerbausteine / 3.5-Di-tert-butylstyrenes: Synthesis of Bulky Polymer Building Blocks
Authors: Risch Nikolaus , Meyer-Roscher Bernd , Langhals Maria 
Published: February 2015

Abstract
We report the synthesis of 3,5-di-tert-butylstyrene (5). The alkylation of toluene with tertbutylchloride establishes the 1,3,5-substitution pattern. A Wittig reaction introduces the C1 unit. This and similar bulky styrene derivatives will be used as special building blocks for polymer design.
Kristallstruktur des „supramolekularen“ Quecksilber(II)chlorid-thiocyanat- Hexamethylentetramin-Addukts Hg(SCN)2 · 2HgCl2 · 2C6H12N4 / Crystal Structure of the “Supramolecular” Mercury(II) Chloride Thiocyanate Hexam ethylenetetram ine Adduct Hg(SCN)2 · 2HgCl2 · 2C6H12N4
Authors: Pickardt Joachim , Gong Gill-Taik , Röleke Dietmar 
Published: February 2015

Abstract
Crystals of the adduct Hg(SCN)2 · 2HgCl2·2C6H12N4 were obtained from an aqueous solution containing 0.1 mol/l hexamethylenetetramine and 0.05 mol/l potassium thiocyanate and mercury(II) chloride. The compound crystallizes monoclinically; space group P21/n, a = 767.3(4), b = 1854.7(7), c = 872.5(7) pm, and β = 101.48(5)°. The structure consists of a net­ work of chains -Cl-Hg-Cl-Hg- and -(Cl-Hg-)2NCS-Hg-SCN-(Hg-Cl)2-which share common Hg atoms and form distorted hexagonal and trigonal channels. The hexamethylenetetramine molecules lie in the hexagonal channels. They act as μ3 bridging ligands, forming bonds to two Hg atoms in a given layer, and an additional bond to a Hg atom a neighbouring layer.
Die Kristallstrukturen von Li[PF6] und Li[AsF6]: Zur Kristallchemie von Verbindungen A[EVF6] / The Crystal Structures of Li[PF6] and Li[AsF6]: On the Crystal Chemistry of Compounds A[EVF6]
Authors: Röhr Caroline , Kniep Rüdiger 
Published: February 2015

Li[PF6] (rhombohedral, R3̅; a = 493.2(2), c = 1265.8(4) pm; Z = 3) and Li[AsF6] (rhom­bohedral, R3̅; a = 501.6(1), c = 1302.8(4) pm; Z = 3) are isotypes of the Li[BiF6] structure. The Ev-elements P(As) as well as lithium are in a nearly perfect octahedral coordination by fluorine.
The crystal structures of the fluoro-compounds A[EVF6] (A = Li, Na, K, Rb, Cs; Ev = P, As, Sb, Bi) can be divided in two groups: i. with A and Ev in a NaCl like arrangement and ii. with A and Ev in a CsCl like arrangement. The coordination numbers (CN) of the A-sites (CN between 6 and 12) depend on the ratio of radii r(EV5+)/r(A+).
Synthesis of Novel 3-Acetyl-2-hydroxy-1-N,N-diacetylaminocarbazole Derivatives
Authors: Sekar M. , Vanitha S. , Prasad K. J. Rajendra 
Published: February 2015

Abstract
The synthesis of hitherto unknown 3-acetyl-2-hydroxy-1-N,N-diacetylaminocarbazole (3a-f), is reported. The hydroxyiminocarbazoles (2a-f), prepared from 1-oxo-1,2,3,4-tetra-hydrocarbazoles (1a -f) on treatment with acetyl chloride in acetic anhydride yielded the title compounds (3a-f).
Tris [(trimethylsilyl)oxy] antimony
Authors: Baier Michael , Angermaier Klaus , Schmidbaur Hubert 
Published: February 2015

Abstract
Tris[(trimethylsilyl)oxy]antimony (Sb(OSiMe3)3, 1) has been prepared from SbCl3 and 3 equiv. of LiOSiMe3 in diethylether. According to mass spectrometric and NMR spectroscopic data, 1 appears to be a monomer in solution and in the gas phase. Dimerisation occurs, however, in the solid state as verified by an X-ray crystal structure determination. The unit cell contains three crystallographically independent monomers, two of which form one type of dimer, while the other is part of a centrosymmetrical dimer. In both types of dimers two Sb atoms are connected via two OSiMe3 groups to form distorted Sb2O2-squares. Together with the remaining 4 OSiMe3 groups and the two stereochemically active lone pairs, each Sb exhibits a trigonal bipyramidal coordination.
Ein cyclisches Organoantimon(III)-oxid, (RSbO)4 [R = (Me3Si)2CH] / A Cyclic Organoantim ny(III) Oxide, (RSbO)4 [R = (Me3Si)2CH]
Authors: Breunig Hans Joachim , Mohammed Mohammed A. , E b ert Klaus H. 
Published: February 2015

Abstract
The cyclic organostibane oxide [(Me3Si)2CHSbO]4 (1) has been prepared by reaction of RSbCl2 with KOH in water/diethylether and crystallization as 1·H2O from petroleum ether. The crystal structure of 1·H2O consists of a boat shaped 8-membered Sb4O4 heterocycle with the substituents in trans positions (distances Sb-O 197.0(3) pm, Sb-C 217.2(4) pm, angles O-Sb-O 93.2(1)°, Sb-O-Sb 122.3(2)°, O-Sb-C 96.2(1)°) and disordered water molecules. Crystal data: tetragonal, space group 14̅; a = 16.091(2), c = 11.057(2) Å; Z = 2.
Fünffach koordinierte Komplexe vom Typ [tripodM-(ortho-(X)(Y)C6H4)]n (X, Y = O, S) bei d5-, d6- und d7-systemen. synthese, struktur, elektrochemie und esr-spektren / Five-coordinate complexes [tripodM-(ortho-(X)(Y)C6H4)]n (X, Y = O, S) with d5-,d6- and d7-Systems. Synthesis, Structure, Electrochemistry and ESR-Spectra
Authors: Körner Volkmar , Asam Alexander , Hüttner Gottfried , Zsolnai Laszlo , Büchner Michael 
Published: February 2015

The d6-Co(III)-species [tripodCo-(ortho-(X)(Y)C6H4)]+ (X, Y = O, S, tripod = CH3C(CH2PPh2)3) 1 are reversibly reduced to the neutral d7-Co(II)-compounds [tripodCo-(ortho-(X)(Y)C6H4)] (X, Y = O, S) 2. Both species show fivefold coordination of cobalt with coordination polyhedra in between the limits of the square pyramid and the trigonal bipyramid respectively. The low-spin d7-species 2 give clearly resolved ESR-spectra revealing the coexistence of two geometric isomers above -80 °C, with only one isomer persistent at temperatures around 100 K.
As an analogous d5-system [benzyltripodFe-(ortho-(S)(S)C6H4)]+ 3 (benzyltripod = C6H5CH2C(CH2PPh2)3) has been obtained from [benzyltripodFe(NCCH3)3]2+ and C6H6S2. Alternatively complexes of this type, e.g. [tripodFe-(ortho-(S)(S)C6H4)]+ 4, may be prepared from Fe(H2O)6(BF4)2/tripod/C6H6S2 when the reaction mixture is activated by acidification with HBF4. The geometry of the d5-species 3 and 4 is close to a trigonal bipyramid
Borylation of 1,1′-Dibromoferrocene and Alkylferrocenes
Authors: Wrackmeyer Bernd , Dörfler Udo , Rinck Joachim , Herberhold Max 
Published: February 2015

Abstract
1,1′-Dibromoferrocene (1) and alkylferrocenes (ethylferrocene 2a, n-butyiferrocene 2b) react stepwise with an excess of boron tribromide in hexane to give first the monoborylated ferrocenes (3, 5a, 6a) followed by the diborylated ferrocenes (4, 7a, 8a). In the case of 4, two diastereomers are obtained. The triborylated ferrocene derivatives 9a,b are obtained in high yield as the final products. The proposed structures of all borylated ferrocenes are supported by a consistent set of 1H, 13C and 11B NMR data.
Factors Influencing the Acid Lability of Substituted Arylsulphonyl Arginine Protecting Groups
Authors: Ali Syed Safdar , Echner Hartmut , Khan Khalid Mohammed , Schröder Christoph , Hasan Mashooda , Atta-ur-Rahman  , Voelter Wolfgang 
Published: February 2015

Abstract
The kinetics of hydrolysis of new, NG-protected 2,4,6-triisopropylbenzene-sulphonyl (6). 4-methoxy-3,5-di-tert-butylbenzenesulphonyl (12) and phenanthrene-3-sulphonyl (17) Fmoc derivatives of L-arginine (1) in comparison with commercially available Fmoc-Arg(Mtr)-OH (Mtr = 4-methoxy-2,3,6-trimethyl-benzenesulphonyl (2)) are studies. The acid lability of the arylsulphonyl group is decreasing as follows Mtr > Tip > Mtbs > Phen. The effect of electron- donating alkyl groups as substituents in increasing the acid lability of the arylsulphonyl residue seems to be in the order of methyl > isopropyl > tert-butyl while the effect of extended derealization does not appreciably increase the acid lability.
Zur Reaktion von Carben-Addukten des Kohlenstoffdisulfids mit Brom und Iod [1] / On the Reaction of Carbene Adducts of Carbon Disulfide with Bromine and Iodine [1]
Authors: Kuhn Norbert , Bohnen Hans , Henkel Gerald 
Published: February 2015

Abstract
The carbene adducts 3 are obtained as stable solids from the imidazol-2-ylidenes 1 and CS2. 3 c reacts with bromine to give the cationic bromosulfane 4, whereas iodine forms the charge-transfer adduct 5. Oxidative coupling to the dicationic disulfane 6 is observed with excess of iodine. The X-ray structure analyses of 3b, 4, 5 and 6 are reported.