bluuebunny/crossref_metadata_2025 huggingface dataset:
Notizen: Cross Polarization in Electron Nuclear Double Resonance by Satisfying the Hartmann-Hahn Condition
Authors: Brunner H , Fritsch R. H. , Hausser K. H.
Published: February 2015

The polarization of electronic spins S is transferred to nuclear spins I by cross relaxation in an electron nuclear double resonance experiment. The cross relaxation becomes very efficient with a time constant Tcr of about 0.5 microseconds if the Hartmann-Hahn condition is satisfied for electronic spins S spin-lock ed to the microwave field B1,S in the rotating frame and for proton spins / in the static magnetic field B0.
Methyl Group Rotation and Tunnellingin Crystals of 5-Membered Ring Molecules
Authors: Montjoie A.-S. , Müller-Warmuth W. , Stiller Hildegard , Stanislawski J.
Published: February 2015

1H NMR spin-lattice relaxation times T1 and -if accessible -level-crossing peaks and inelastic neutron scattering spectra have been measured for solid 2-and 3-methylfuran, 2-and 3-methylthiophene, 3-and 4-methylpyrazole, 1-methylimidazole, and 5-methylisoxazole. From the tunnel splittings, the torsional excitations and the NMR relaxation rates, the molecular dynamics of the methyl rotators has been evaluated between the limits of quantum tunnelling at low temperatures and thermally activated random reorientation at elevated temperatures.
Energietransfer im System Ca3La2W2O12:Mn,Nd,Yb
Authors: Hirrle R. , Kemmler-Sack S.
Published: February 2015

Energy Transfer in the System Ca3La2W2O12:Mn, Nd, Yb

On codoping of the host Ca3La2W2O12 with Mn4+ and Nd3+ or Mn4+ and Yb3+ ,respectively, an efficient energy transfer Mn4+ → Nd3+ or Mn4+ → Yb3+ operates. The simultaneous introduc­tion of Mn4+ , Nd3+ and Yb3+ yields additionally an energy transfer Nd3+ → Yb3+ . The excitation, emission and diffuse reflectance spectra are discussed.
Gas Phase Basicity of Substituted Benzaldehydes and Methylbenzoates.A Semiempirical Molecular Orbital Study
Authors: Fabian Walter
Published: February 2015

The semiempirical AM1 method is used to calculate relative proton affinities of a series of meta-and para-substituted benzaldehydes and methylbenzoates. Close agreement between the results of these calculations and experimental relative gas phase basicities could be obtained. The influence of a substituent on the stability of both neutral as well as protonated forms is estimated via isodesmic reactions. In any case the influence of a substituent is most pronounced in the protonated carbonyl compound. The contribution of the inductive/field effect of a substituent is approximated by the results of isolated molecule calculations. The resonance contribution is estimated by the charge transfer to or from the substituent as revealed by a Mulliken population analysis. Alternatively, the difference between isodesmic stabilization energies and isolated molecule results for the protonated compounds is taken as a measure for the resonance effect. Linear regression analyses with these substituent parameters show good correlation with both experimental as well as calculated relative basicities of the compounds studied.
The Ground State Microwave Spectrum of 2-Fluoropropane
Authors: Meyer Michael , Dreizler Helmut
Published: February 2015

We determined the internal rotation barrier V3 = 3.285 kcal/mol (13.74 kJ/mol) and the moment of inertia Iα = 3.184 amuÅ2 of the methyl groups from the ground state microwave spectrum of 2-fluoropropane. Additionally the rotational constants, the quartic and some sextic centrifugal distortion constants are reported. The analysis of the Stark effect leads to the dipole moment 1.958 D.
Intermolecular Potential Function for Ammonia-Lithium Ion Based on Ab-Initio Calculations
Authors: Hannongbua Supot V. , Kokpol Sirirat U. , Kreawsrikul Suchada , Polman Supa , Rode Bernd M.
Published: February 2015

The intermolecular interaction for ammonia-lithium ion has been investigated based on the LCAO-MO-SCF method, with double zeta basis set including polarization. The potential functions were constructed firstly from 50 ammonia configuration. Then 50 additional random configurations were added to test the quality of the function. The results show that even 100 configurations are not enough to obtain convergency, but the quality of the function obtained by well-selected points of the surface is already sufficient for simulation purposes.
Supersonic Vortex Gerdien Arc with Magnetic Thermal Insulation
Authors: Winterberg F.
Published: February 2015

Temperatures up to ~ 5 x 104 oK have been obtained with water vortex Gerdien arcs, and temperatures of ~ 105oK have been reached in hydrogen plasma arcs with magnetic thermal insulation through an externally applied strong magnetic field.

It is suggested that a further increase in arc temperatures up to 106
oK can conceivably be attained by a combination of both techniques, using a Gerdien arc with a supersonic hydrogen gas vortex.
HHigh Resolution Spectroscopy Using a Stabilized Diode Laser: the 2υ9 Band of HNO3
Authors: Giesen Thomas , Harter M. , Schieder R. , Winnewisser G. , Yamada K.M.T.
Published: February 2015

The high resolution spectrum of the 2 υ9 band of HNO3 has been recorded by a tunable diode laser spectrometer with a newly developed frequency stabilization technique. The spectral data were digitally stored and processed by a dedicated micro-computer in order to improve the sensitivity and the precision of the measurements. In addition to the anomalies due to the Fermi resonance with the υ5 = 1 state, we have observed the line doubling caused by the internal rotation of the OH group.
Electrical Properties for HCO+ and NNH+ from Fourth-Order Møller-Plesset Perturbation Theory
Authors: Maroulis George
Published: February 2015

Electric multipole moments and static polarizabilities are reported for HCO+ and NNH+ . Both molecular ions are of great importance to interstellar matter chemistry. All properties were calculated from the energy of the molecule in the presence of distant electric charges. Electron correlation effects were taken into account via SDQ-MPPT(4), fourth-order Møller-Plesset Perturbation Theory with single, double and quadrupole substitutions from the reference SCF wavefunction. With the exception of the dipole moment, values for the other properties studied in this work appear in the literature for the first time. The dipole moment (relative to the centre of mass) and the axial and perpendicular components of the dipole polarizability are 1.515 ea0, 13.39 and 6.88 e2a2Eh
+1 respectively for HCO+ and 1.328 ea0, 13.81 and 5.70 e2a2
0Eh
-1 for NNH+ .
Transition Probabilities of Cull Lines
Authors: Neger T. , Jäger H.
Published: February 2015

Relative transition probabilities of 7 CuII lines in the visible spectral region have been measured by side-on observation of a plasma jet emerging out of a capillary as well as by using an axial discharge-type of an exploding copper wire. The results are compared with those of two other experiments.
Zero-Point Energy Shifts in Hydrides of the Elements upon H/D Isotope Substitutions and Their Periodicity
Authors: Oi Takao , Aikawa Makoto , Kakihana Hidetake , Ishida Takanobu
Published: February 2015

Periodicities are established among the zero-point energy shifts, δ (ZPE), of AHn (n =1-4) type hydrides of the elements upon mono H/D isotope substitutions. δ (ZPE) for diatomic hydrides is correlated with the position of the element A in the periodic table. The contribution of the A-H stretching force constant to δ (ZPE) is to a good approximation a linear function of the square root of the force constant, irrespective of the molecular type. A similar correlation is also found between the square root of the H-A-H bending force constant and its contribution to δ (ZPE).
Negative Energy Waves in the Frame work of Vlasov -Maxwell Theory
Authors: Pfirsch Dieter
Published: February 2015

On the basis of a variational formulation of the Vlasov-Maxwell theory it was recently shown that, for instance, all magnetically confined plasmas allow the existence of negative energy waves. Such waves can become nonlinearly and dissipatively unstable and might therefore be of importance in explaining anomalous transport. The proof of this result uses infinitely strongly localized perturba­tions. This is, however, not necessary: in this paper it is shown by discussing general, homogeneous, magnetized plasmas that the necessary localization is related to the average gyroradius rg of the relevant particle species. For unstable plasmas the extent or wavelengths of negative energy waves can be of the order of rg, whereas for linearly stable plasmas the extent can be a small fraction of rg.
Detection of Gas-Phase Hydrogentrisulfide, HSSSH
Authors: Mauer D. , Winnewisser G. , Yamada Koichi M. T. , Hahn J. , Reinartz K.
Published: February 2015

Abstract The rotational spectrum of gas phase HSSSH has been recorded for the first time in absorption with the Cologne free-space-cell millimeterwave spectrometer. In the frequency region between 80 and 300 GHz a prominent series of Q-branches has been observed and assigned. The hitherto identified rotational lines unambigously arise from a perpendicular-type spectrum. In addition, successive J lines of the compact Q-branches show no indication of the easily detectable intensity alternation which arises when the molecule possesses an axis of symmetry due to nuclear spin statistical weights. Therefore the geometrical structure of the molecule does not have a C2 axis of symmetry. The present data are not complete enough for a unique structure determination. However on the basis of the present data we can definitely rule out conformations with C2 or C2v symmetry to be responsible for the strongest observed transitions of the spectrum. The molecule is not floppy as predicted from semi empirical MO calculations. On the contrary the conformation observed is rather rigidly locked into one position with no sign of possible internal rotation. We consider a sulfur triangle with the two hydrogen atoms sticking out symmetrically to the same side of the SSS-plane to be the most likely structure.
Theoretical Approach in Explanation of Energy Donor Properties of 1,4-Dioxane and 1,4-Dioxane-Water Complexes
Authors: Polacki Zenon , Rak Janusz
Published: February 2015

Abstract The CNDO/2 CI method was used for the examination of 1,4-dioxane and 1,4-dioxane-water complexes (2:1), taking into account various conformations of the dioxane molecule. The energies of the molecules in the ground and excited states, the energies of hydrogen bond formation, the dipole moments, the transition moments, and the oscillator strengths for both the complexed and isolated 1,4-dioxane molecules were evaluated. The results of these studies are used to reveal the influence of water on the features of energy transfer from excited, by y-radiation, 1,4-dioxane or dioxane-water complexes to the luminophor.
Free Radicals in X-Irradiated Ethylene Glycol Crystals
Authors: Awadelkarim O. , Claesson O. , Lund A.
Published: February 2015

ESR experiments aiming at clarifying the structure of radicals present in X-irradiated crystals of ethylene glycol and other diols are reported. By comparison with data for the corresponding glasses it is concluded that a major source of free radicals is the decomposition of trapped electrons. The radical structure is identified.
The Intramolecular Electric Field Gradient at the 14N-Nucleus in Monofluoroacetonitrile and an Improved Partial r0-Structure of the Molecule
Authors: Andolfatto M. , Krause H. , Sutter D. H. , Palmer M. H.
Published: February 2015

The 14N quadrupole coupling tensor in CH2FCN and CD2FCN was determined from the hyperfine splittings of low J rotational transitions to give indirect structural information on the geometry of the CCN chain.

The CCN chain turns out to be slightly bent (2° away from F), in excellent agreement with the result of an earlier ab initio calculation.
Nuclear Quadrupole Hyperfine Structure in the Rotational Spectrum of 3-Chloropyridine. An Application of Microwave-Microwave Double Resonance Fourier Transform Spectroscopy
Authors: Heineking N. , Dreizler H.
Published: February 2015

We redetermined the rotational and the chlorine-35 and nitrogen-14 nuclear quadrupole coupling constants of 3-chloropyridine. The values are A = 5839.5330(12) MHz, B = 1604.1875(6) MHz, and C = 1258.3121 (5) MHz for the rotational constants, and χaa(Cl) = - 72.255(19) MHz, χbb(Cl) = + 38.500(13) MHz, χcc(Cl) = + 33.755(23) MHz and χaa(N) = - 0.009(13) MHz, χbb(N) = - 3.473(10) MHz, χCC(N) = + 3.482(16) MHz for the chlorine-35 and nitrogen-14 nuclear quadrupole coupling constants, respectively.

Application of double resonance modulation technique is shown to greatly simplify the assign­ment of hyperfine structure components even of weak rotational transitions.
Properties of a Set of Symmetric Maxwellian Equations
Authors: Guéret Pierre
Published: February 2015

A set of fully symmetric maxwellian equations is proposed, with a quantum mechanical coupling term between matter and fields. Its relativistic transformation properties and conservation laws are presented. Dual, monopole-like solutions are described, which have properties consistent with those of the Dirac electron and magnetic monopole. The spatial extent of the monopole fields is proposed to be bound within two extreme radial limits rp and R0 such that α In (R0/rp) ≡ 1, where α ≃ 1/137 is the electromagnetic fine structure constant, yielding for the ratio R0/rp a very large number in the order of the ratio of the so-called universe radius to the Planck length.
NMR Investigations of the Pitch Dependence of Self-diffusion in Cholesteric Liquid Crystals
Authors: Oehler S. , Stannarius R. , Schmiedel H.
Published: February 2015

Self-diffusion in the isotropic and twisted nematic phases of mesogenic substances has been studied by means of 1H- and 13C-NMR.

From the line shape analysis of the recorded 13C-NMR spectra we obtained the diffussion coefficient D⊥ along the helical pitch.

Various concentrations of a chiral additive changed the pitch P0 of a nematic mixture of phenyl-benzoates from 4.7 μm to 7.8 μm. The measured values of D⊥ were in the range from 2.4 · 10-12 m2 s-1 to 1.9 · 10-11 m2 s-1 We found an Arrhenius behaviour with an activation energy of about 55 kJ/mole nearly independent of the pitch. The obtained data for D⊥ seem to have a lower than quadratic dependence on P0.
Molecular gᅩ-value, Magnetic Susceptibility Anisotropy, and Deuterium Quadrupole Coupling Constantin Deuterodiacetylene
Authors: Böttcher O. , Heineking N. , Andolfatto M. , Sutter D. H.
Published: February 2015

The rotational Zeeman effect in the J′ → J = 2 → 1 rotational transition and the deuterium quadrupole coupling effect in the J′→J = 1 → 0 transition have been observed for D - C = C - C = C - H using a microwave Fourier transform (MWFT)-spectrometer.

The molecular parameters determined are: rotational constant B0= 4084.452 MHz, deuterium quadrupole coupling constant e q Q (D) = 217(6) kHz, molecular gᅩ-value = 0.0073(1) and molecular magnetic susceptibility anisotropy (Xᅩ - X||) = 11.5(7) 10-6 erg G-2mol-1.
NQR-NMR and Raman Study of a Structural Phase Transitionin (NH4)2PbCl6
Authors: Dimitropoulos C. , Pelzl J.
Published: February 2015

The temperature dependence of the chlorine NQR frequency and spin-lattice relaxation rate indicate a structural phase transformation in (NH4)2PbCl6 at 80 K similar to that observed in (NH4)2TeCl6 at 85 K. Both transitions are characterized by a discontinuity of the temperature derivative of the NQR frequency shift and by a cusp in the NQR spin-lattice relaxation rate, but no splitting of the NQR line is observed below Tc. These observations point towards a transition that leaves the chlorine sites equivalent, such as a small angle rotation of the MXg2-
6octahedra about their threefold axis. Supplementary 1H-NMR measurements have been performed to investigate the direct influence of NH4
+ motion on the Cl-NQR. The phase transitions in mixed (NH4: K)2PbCl6 crystals have also been studied.
Extended Analysis of the Rotational Spectrum of HCCF
Authors: Rohwer F. , Hinze R. , Guarnieri A.
Published: February 2015

The microwave spectrum of fluoroacetylene (HCCF) has been measured in the frequency region 35 -260 GHz. Rotational constants of the ground state and rotational as well as rotation-vibrational interaction constants of several excited states of the C - C - H (ν4) and the C - C - F (ν5) bending vibrations have been obtained.
Transition to Chaos via Collapse of Two-Torus in the Belousov-ZhabotinskyReaction
Authors: Baier Gerold , Wegmann Klaus
Published: February 2015

The transition of the dynamics of the Belousov-Zhabotinsky reaction from large peak oscillations to two-torus and chaos as a function of the flow rate is described.
Streuung langsamer Neutronen an Thorium *
Authors: Waschkowski W. , Knopf K. , Koester L.
Published: February 2015

We determined by means of Christiansen filter technique and transmission measurements the following quantities for thorium:

- the coherent scattering length b =10.31 ± 0.03 fm,

- the absorption cross section at 0.0253 eV σγ= 7.34 ± 0.09 b,

- the potential scattering radius R = 9.6 ± 0.2 fm.

In combination with scattering cross sections in the eV-energy region we obtained information about bound levels at negative energies.
On the Law of Equipartition for Translational Motion of Excited Molecules in Equilibrium with Thermal Radiation
Authors: Lavenda B. H.
Published: February 2015

Einstein’s radiation theory consists of two parts: the derivation of Planck's radiation law from a physical mechanism of absorption and emission of radiation by excited molecules that are in thermal equilibrium with the radiation field and a demonstration of the validity of the law of equipartition of energy for the translational motion of the molecules. Several incongruities are observed: Einstein could not have legitimately substituted back into his dynamical equilibrium condition, valid at any finite temperature, a limiting condition between the coefficients of absorption and stimulated emission that he obtained in the high temperature limit. His justification of the law of equipartition involves, on the one hand, treating the motion of the excited molecule as brownian motion while, on the other hand, employing special relativity to obtain an expression for the diffusion coefficient. In the former the velocity of the molecule is a stochastic variable while in the latter it is a uniform velocity. Hence equipartition does not hold for the translational motion.
Tunable Diode Laser Spectra and Assignment of the 748 cm-1 Band of Propane
Authors: Gassler G. , Reißenauer B. , Hüttner W.
Published: February 2015

The rotational structure of the 748 cm-1 c-type CH2-rocking fundamental of propane was analysed using tunable diode laser (TDL) techniques. On grounds of a low-resolution Fourier transform (FTIR) spectrum and of the known ground-state rotational and centrifugal-distortion constants, some 700 transitions were measured and assigned in several regions of the band. The upper-state constants determined in this way allow the prediction of rovibrational frequencies to within 0.003 cm-1, covering quantum states up to J = 50 and Ka = 20. The band appears unperturbed.
Application of Vapor Pressure Isotope Effect to the Determinationof Vibrational Anharmonicity in the Liquid Phase
Authors: Tóth Katalin , Jancsó Gabor
Published: February 2015

The experimentally observed H/D vapor pressure isotope effects in chloroform and bromoform were combined with reliable spectroscopic data from the literature in order to obtain information on the change of the potential curve of the CH stretching motion on vapor-liquid transition. The parameters studied include the Morse potential parameters, the anharmonicity constant and the harmonic, cubic and quartic force constants in both phases. While the anharmonic character of the potential energy curve of the CH oscillator of chloroform has been found to decrease on condensation. the opposite behavior has been observed in the case of bromoform.
Isotope Effects in Kinetic Enolate Formation from 2-Pentanoneand 2-Pentanone-1,1,1-d3
Authors: Xie L. , Saunders Jr. W. H.
Published: February 2015

2-Pentanone and 2-pentanone-1,1,1-d3 were treated with three-fold excesses of lithium diisopropylamide (LDA) or lithium hexamethyldisilazide (LHMDS) in tetrahydrofuran (THF) with and without hexamethylphosphoric triamide (HMPA, 3 mol per mol of base) at temperatures ranging from 24 to - 70 °C. The deuterium kinetic isotope effects calculated from the product ratios (measured by GLC as trimethylsilyl enol ethers) showed a range of temperature dependences: none (LDA in THF), attenuated with AH/AD = 2.53 (LHMDS in THF), and normal with AH/AD~0.6 indicating moderate tunneling (LDA and LHMDS in THF-HMPA). The variation in temperature dependence is attributed to reaction via multiple base species in which HMPA affects the equilibria between the base species.
NMR Stratagems for the Study of Multiple Kinetic Hydrogen/Deuterium Isotope Effectsof Proton Exchange. Example: Di-p-fluorophenylformamidine/THF
Authors: Limbach Hans-Heinrich , Meschede Ludger , Scherer Gerd
Published: February 2015

Stratagems are presented for the determination of kinetic isotope effects of proton exchange reactions by dynamic NMR spectroscopy. In such experiments, lineshape analyses and/or polarization transfer experiments are performed on the exchanging protons or deuterons as well as on remote spins, as a function of the deuterium fraction in the mobile proton sites. These methods are NMR analogs of previous proton inventory techniques involving classical kinetic methods. A theory is developed in order to derive the kinetic isotope effects as well as the number of transferred protons from the experimental NMR spectra. The technique is then applied to the problem of proton exchange in the system 15N,15N′-di-p-fluorophenylibrmamidine, a nitrogen analog of formic acid, dissolved in tetrahydrofuran-d8 (THF). DFFA forms two conformers in THF to which s-trans and s-cis structures have been assigned. Only the s-trans conformer is able to dimerize and exchange protons. Lineshape simulations and magnetization transfer experiments were carried out at 189,2 K, at a concentration of 0.02 mol l-1, as a function of the deuterium fraction D in the 1H-15N sites. Using 1H NMR spectroscopy, a linear dependence of the inverse proton lifetimes on D was observed. From this it was concluded that two protons are transported in the rate limiting step of the proton exchange. This result is expected for a double proton transfer in an s-trans dimer with a cyclic structure. The full kinetic HH/HD/DD isotope effects of 233:11:1 at 189 K were determined through 19F NMR experiments on the same samples. The deviation from the rule of geometric mean, although substantial, is much smaller than found in previous studies of intramolecular HH transfer reactions. Possible causes of this effect are discussed.
Calculationof Equilibrium Isotope Effects in a Conformationally Mobile Carbocation
Authors: Saunders Martin , Cline Gary W. , Wolfsberg Max
Published: February 2015

The rapid, degenerate 1,2-hydride shift in 2,3-dimethyl-2-butyl cation in stable solution in SbF5/SO2C1F was perturbed by deuterium and 13C leading to splittings observed by 13C NMR spectroscopy over a range of temperatures. Accurate values for equilibrium isotope effects were obtained from these data. Theoretical calculations of the equilibrium isotope effects were performed using the Gaussian-86 program to obtain an optimized geometry and the Cartesian force constant matrix, followed by the program QUIVER which applies the Bigeleisen-Mayer method. When all of the conformers, which are in rapid equilibrium, were considered specifically, quite good agreement between theory and experiment was obtained.
Relationships of the Polarisability with the Number of Valence Electrons, the Total Energy and the Second Hyperpolarisability of Methylbenzenes
Authors: Waite J. , Papadopoulos M. G.
Published: February 2015

The total energy and polarisability of 12 methylbenzenes have been computed by employing the CHF-PT-EB-CNDO method. The relationships between the normalized polarisability, the total energy, the second hyperpolarisability and the number of valence electrons of the studied compounds are discussed. Variations in the polarisation properties induced by structural changes are also commented upon.
Improved Spectroscopic Constants for 14C16O2 Obtained from the ν3 Band
Authors: Dobos S. , Winnewisser G . , Kling F. , Mink J.
Published: February 2015

The absorption spectra of carrier free 14C16O2 in the spectral range of 2290-2150 cm−1 by a medium resolution FTIR spectrometer, and the spectral region of 2258 − 2229 cm−1 with a high resolution tunable diode laser spectrometer have been recorded. Spectroscopic constants were calculated from the 0001 − 0000 and 0111 −0110 transitions.
79,81Br−127I−NQR, and Crystal Structure of Glycyl-l-alanine Hydrobromide Monohydrate and Hydroiodide Monohydrate
Authors: Kehrer Armin , Dou Shi-qi , Weiss Alarich
Published: February 2015

The crystal structures of glycyl-l-alanine hydrobromide monohydrate, 1, and glycyl-l-alanine hydroiodide monohydrate, 2, were determined and the temperature dependence of the 127I NQR frequencies was investigated in the temperature range 77 <̳T/K <̳ 370. The 127I NQR frequencies are strongly influenced by hydrogen bonds and this is proved by the frequency shift of the H ⇄ D exchange. By deuteration the nuclear quadrupole coupling constant e2 qQh−1(127I) of 2 is shifted downwards 2.72 MHz at room temperature.

The title compounds are isotype, and at room temperature they crystallize monoclinic with the space group C2
2 − P21 with two molecules in the unit cell. The lattice constants for 1 are a = 1068.7 pm, b = 614.1 pm, c = 762.0 pm, and β= 108.55° and for 2 are a = 1093.3 pm, 6 = 637.1 pm, c = 770.9 pm, and β= 107.29°.
A Microwave Fourier Transform Spectrometer in the Region from 4 to 6 GHz with Double Resonance Modulation
Authors: Ehrlichmann H. , Grabow J.-U. , Dreizler H. , Heineking N. , Schwarz R. , Andresen U.
Published: February 2015

We report on the experimental set up and performance of a microwave Fourier transform spectrometer for the G band from 4 to 6 GHz. The sensitivity, achievable linewidth, and resolution capability is demonstrated by measurements of rotational transitions of various molecules.
Nitrogen and Deuterium Hyperfine Structure in the Rotational Spectrum of Piperidine
Authors: Ehrlichmann H. , Grabow J.-U. , Dreizler H. , Heineking N. , Andolfatto M.
Published: February 2015

We reinvestigated by microwave Fourier transform spectroscopy the rotational spectra of the axial and equatorial isotopomers of piperidine and N-deutero piperidine. The rotational, centrifugal, and nitrogen quadrupole coupling constants were improved, the deuterium quadrupole coupling constants were determined. The principal coupling tensor elements for nitrogen were estimated.
Comets : A Key to Solar System Formation
Authors: Keller Horst Uwe
Published: February 2015

Four lines of information on comets are discussed: their orbits, their relation to other bodies of the planetary system, their physical state and chemical composition, and implications of recent observations of the nucleus of comet Halley. The in situ measurements during the flybys of comet Halley strongly support the assumption that comets are members of the solar system and were created during its formation. The region (heliocentric distance) of their formation is, however, still difficult to assess. The size, shape, and topography of the cometary nucleus suggest that it was formed from relatively large subnuclei in a region of the primordial solar nebula where relative velocities were sufficiently small. There are indications that some of the interplanetary dust particles in the Earth atmosphre may originate from comets.
Noble Gas Record of Japanese Chondrites
Authors: Takaoka Nobuo , Shima Masako , Wakabayashi Fumitaka
Published: February 2015

Concentrations and isotopic ratios of noble gases are reported for nineteen Japanese chondrites. Among those, Nio (H3-4) is a solar-gas-rich meteorite.

U/Th - He ages are younger than K - Ar ages for all meteorites studied. Six of the nine L-chondrites give significantly young K-Ar ages, suggesting gas loss by impact shock heating. The remaining three L-chondrites and seven of the ten H-chondrites have K-Ar ages older than 4 Ga. The L-chondrite Nogata and the H-chondrites Numakai, Ogi and Higashi-Koen have concordant ages.

Cosmic-ray exposure ages for six of the H-chondrites show clustering around the 6-Myr peak in the distribution of exposure ages, while those for the L-chondrites, ranging from 8.2 to 64 Myr, do not show clustering.

Fukutomi (L4) contains trapped 36Ar in excess, 3.5 times enriched compared to the highest value so far reported for type-4 ordinary chondrites except solar-gas-rich chondrites. The 36Ar/132Xe and 84Kr/132Xe ratios fit along a mixing line between a planetary and a sub-solar (or argon-rich) component found in separates of E-chondrites [43], The Xe isotopic composition is identical with that in Abee and Kenna. The isotopic signatures suggest that this meteorite may contain mineral fragments bearing the noble gas component found in E-chondrites or ureilites.

Fukutomi also contains 80Kr, 82Kr and 128Xe produced by epithermal neutron captures on 79Kr, 81Kr and 127I, respectively. From the neutron-produced Kr, the preatmospheric minimum radius is estimated to be 20 cm with an assumption of a spherical meteoroid.
The Intra-annular Internal Heavy-atom Effect on the Fluorescence and Phosphorescence Properties of Oxygen, Sulphur or Selenium Containing Heterocyclic Systems Related to Dibenzo [b,n] perylene
Authors: Zander M.
Published: February 2015

Fluorescence and phosphorescence properties of dibenzo [2,3:10,11] perylo [1,12-bcd] furan (1), dibenzo [2,3:10,11] perylo [1,12-bcd] thiophene (2), and dibenzo [2,3:10,11 ] perylo [1,12-bcd] selenophene (3) have been studied. Fluorescence quantum yields as well as phosphorescence lifetimes correlate linearly with

where ck are the Hückel AO coefficients in the HOMO of the parent carbocyclic system dibenzo [b, n] perylene (4) on carbon centres k to which the hetero-atom is bound, and ζ is the spin-orbit coupling constant of the heavy-atom present. The half-value concentration of fluorescence quenching (quencher: methyl iodide) of 1 - 3 increases with increasing strength of the internal heavy-atom effect present
Investigation of the Reaction of Naphthalene with 0(3P) in the Gas Phase
Authors: Frerichs H. , Koch R. , Tappe M. , Wagner H. Gg.
Published: February 2015

The rate of the reaction between naphthalene and atomic oxygen in the electronic ground state was determined in a discharge flow system with mass spectrometric detection for temperatures between 362 and 773 K. All measurements were performed in an excess of O atoms over hydrocarbon. The second order rate constant was determined to be

Kinetic data are compared with data about the reactions of other aromatic substances and atomic oxygen in the ground state. Some possible reaction channels are discussed
The Effect of Substituents on the Polarity in the First Excited Singlet State of Some trans-Styryl-Methyl-Sulfones
Authors: Kawski A. , Kubicki A. , Czajko J.
Published: February 2015

The effect of substituents R (R=N(CH3)2, OCH3, CH3, H, Cl, Br, CN) on the polarity of trans-styryl-methyl-sulfones in the first excited singlet state is investigated. Linear relations are found between the dipole moment in the excited state, μe, and the Hammett constant, σp
+ , and also between μe and the dipole moment in the ground state, μg. On increasing the electron-donor power of R, μe grows faster than μg.
Deuteron Magnetic Resonance (DMR) - Study on CD3NH3HgCl3
Authors: Körfer Martin , Kind Raymond , Fuess Hartmut
Published: February 2015

Deuteron magnetic resonance (DMR) spectroscopic was performed on a single crystal of CD3NH3HgCl3. The electric field gradient tensors of the independent CD3NH3
+- groups were determined by quadrupole perturbed NMR. NMR-NQR-rotation patterns were recorded in the ferro- (T = 295 K) and paraelectric (F = 342 K) phases. In the ferroelectric phase a precessional motion of the CD3NH3
+-group was detected. The angle %(T) between the axis of the molcculc and the precession-axis increases with temperature. In the paraelectric phase the precession of methylammonium is superimposed by an anisotropic 90° -flipping motion. The flipping planes are parallel to the polar axis.
Double Spin Echo Volume Selective NMR Spectroscopy with a 1.5 T Whole Body Imager
Authors: Jung W.-I. , Lutz O.
Published: February 2015

For volume selective nuclear magnetic resonance spectroscopy with protons a modified version of the double spin echo method has been implemented on a 1.5 T whole body imager. The high performance of the localization sequence has been verified with phantoms and tissue. A spectral resolution of about 2 · 10-8 was obtained. The volume elements are well shaped and positioned, the minimal size was 2.2 cm3. Spectra of porcine leg muscle tissue with different echo times are presented.
Self Diffusion in Compressed Fluid CF3Brand CF3Cl
Authors: Has M. , Lüdemann H.-D.
Published: February 2015

Self diffusion coefficients of CF3Br and CF3Cl are given for the temperature range 140 - 430 K at pressures up to 200 MPa. The are analysed by the interacting sphere model.
On Polymorphism of Dysprosium Trichloride
Authors: Zakirýanova Irina D. , Khokhlov Vladimir A. , Salyulev Alexander B. , Korzun Iraida V.
Published: February 2015

For the first time, the structure of crystalline DyCl3 over a wide temperature range from room temperature to melting point was studied by Raman spectroscopy. The phonon modes (cm–1) of dysprosium trichloride (monoclinic crystal lattice of AlCl3 type, Z=4, CN = 6) at room temperature are 257 (A1g), 201 (Eg), 112 (Eg), 88 (A1g), and 63 (Eg). The monoclinic structure of the crystalline DyCl3 C2h
3 symmetry was found to remain constant over the studied temperature range. No polymorphic transformation in the solid state was detected. Gravimetry, calorimetry, and mass spectrometry have been used in addition to support the conclusions made on the basis of Raman spectroscopic data.
Complexes of Copper, Silver, and Gold with Urea Homologues. Crystal Structures of [{µ2-SeC(NH2)2} Ag{SeC(NH2)2}2]2
2+2Cl- • 4 DMF and [Ph3PAu{SC(NHMe)2}]+Cl- • SC(NHMe)2
Authors: Eikens Wolfgang , Jones Peter G. , Lautner Jürgen , Thöne Carsten
Published: February 2015

The title compounds were prepared from chloro(organophosphine)metal(I) complexes and the urea homologues SeC(NH2)2 and SC(NHMe)2 in good yields. Recrystallization of [Ph3,PAg{SeC(NH2)2}]+Cl- from DMF/CH2Cl2 leads in low yield to the dinuclear complex [{µ2-SeC(NH2)2}Ag{SeC(NH2)2}2]2
2+2Cl- • 4DMF. The crystal structure reveals short Ag-Ag contacts and unexpectedly acute angles at the bridging selenium atom. The crystal structure of [Ph3PAu{SC(NHMe)2}]+Cl- • SC(NHMe)2 shows short N•••Cl and N•••S contacts that probably correspond to hydrogen bonding.
Die Kristallstruktur von Gadolinium (III)-sulfit Trihydrat Gd2(S03)3∙ 3H2O / Crystal Structure of Gadolinium(III)-sulfite Trihydrate Gd2(SO3)3 ∙3H2O
Authors: Hummel Hans-Ulrich , Joerg Petra , Pezzei Gerhard , Wolski Alexander
Published: February 2015

Gd2(SO3)3 • 3 H20 is obtained by passing gaseous SO2 through a suspension of Gd2O3 in H2O at room temperature until a clear solution is formed. Single crystals are obtained by heating to 70(2) °C for 6 days. The compound crystallizes in the triclinic space group P 1 with a = 6.499(6), b = 6.621(3), c = 6.954(3) Å, α = 110.71(5), β = 90.54(3), γ = 106.05(1)° and Z = 1.

The two crystallographically different gadolinium atoms are both coordinated by eight oxygen atoms forming distorted square antiprisms. Gd(l) is coordinated by six O atoms of sulfite ligands and two O atoms of water, while Gd(2) is surrounded by seven O atoms of SO3 and one of H2O. Gd-O-bond lengths vary between 2.31(3) and 2.50(3) Å.
Constituents of Euphorbiaceae, 13. Comm. [1] Isolation and Structure Elucidation of Five Cerebrosides from Euphorbia characias L
Authors: Falsone G. , Cateni F. , Baumgartner M. , Lucchini V. , Wagner H. , Seligmann O.
Published: February 2015

Five cerebrosides B-1−B-4 were isolated from the fraction B, obtained from the latex of Euphorbia characias L. On the basis of spectral evidences and chemical reactions they were characterized as (2S, 3S, 4R, 8Z)-1-O-(β-D-glucopyranosyl)-2N-[(2'R)-2'-hydroxytetracosenoyl]-8 (Z)-octadecene-1,3,4-triol-2-amino (B-1), (2S, 3S, 4R, 8Z)-1-O-(β-D-glucopyranosyl)-2 N-[(2'R)-2'-hydroxyhexacosenoyl]-8(Z)-octadecene-1,3,4-triol-2-amino(B-2), (2 S, 3 S,4 R, 8 Z)-1-O-(β-D-glucopyranosyl)-2N-[(2'R)-2'-hydroxyoctacosenoyl]-8 (Z)-octa-decene-1,3,4-triol-2-amino (B-3), (2 S, 3 S, 4R, 8Z)-1-O-(β-D-glucopyranosyl)-2N-[(2'R)-2'-hydroxyhexacosanoyl]-8 (Z)-octadecene-1,3,4-triol-2-amino (B-3a), (2S, 3S, 4R, 8Z)-1-O-(β-D-glucopyranosyl)-2 N-[(2'R)-2'-hydroxyheptacosanoyl]-8 (Z)-octadecene-1,3,4-triol-2-amino (B-4).

Reversed phase column flash chromatography was effective for the isolation of the cerebrosides. FAB-MS spectrometry, 1H NMR, 13C NMR analyses and DQF-COSY and 1H-detected HMQC (single bond and multiple bond) experiments and chemical reactions were useful in providing informations for the structure elucidation.
A Structural Study on Indium Tris-thiocarbamates
Authors: Bhattacharya S. , Seth Miss Neena , Gupta V. D. , Nöth H. , Thomann M.
Published: February 2015

Indium tris(thiocarbamates) In(S2CNiPr2)3 (1), In(SOCNiPr2)3 (2) and In(S2CNC4H4)3 (3) have been synthesized and characterized. Variable temperature 1H NMR spectra of 1 and 2 are reported. The X-ray molecular structures of 1 and 3 are found to be quite similar; the symmetry of the In(S2C)3 unit in 3 is close to point group D3 with small asymmetry in the In-S bonds.
Niedere Hydrate von Aminen. Kristallstrukturen der Hemihydrate von Ethyl- und Diethylamin sowie des Hemi- und Monohydrats von 1-Butylamin [1] / Lower Hydrates of Amines. Crystal Structures of the Hemihydrates of Ethyl- and Diethylamine and the Hemi- and Monohydrate of 1-Butylamine
Authors: Mootz Dietrich , Born Michael
Published: February 2015

The melting diagrams of three systems alkylamine- water have been reexamined and the crystal structures of four lower hydrates determined for the first time. The hydrate EtNH2 · 0.5 H2O , m.p. -72 °C, is triclinic with space group P1̄ and Z = 4 formula units per unit cell of dimensions a = 5.104, b = 8.137, c = 9.394 Å, α = 100.41, β = 98.41 and γ = 97.96° at -150°C. The O and N atoms are hydrogen-bonded into a two-dimensional array 2
∞[ON6/3] analogous to the layer of the Cdl2 structure type. The hydrate Et2NH · 0.5 H2O , m.p. -20 °C, is monoclinic with 12/a, Z = 8 ,a - 8.324, b = 15.090, c = 10.006 Å and β - 103.34° at -100 °C. The O and N atoms are linked into a four-membered ring spiro chain 1
∞[ON4/2] analogous to that in SiS2. The hydrate l-BuNH2 · 0.5H2O (m.p. -57 °C, monoclinic, P 21/c, Z = 8,a = 14.994, b = 5.086, c = 16.15 Å,β - 103.45° at -81 °C) contains essentially the same hydrogen-bonded array as the hydrate EtNH2-0.5 H2O (see above). l-BuNH2-H2O , the only monohydrate investigated besides the three hemihydrates (m.p. -60 °C, monoclinic, C 2/m, Z = 4, a = 9.68, b = 4.238, c = 15.58 Å, β = 94.9° at -81 °C), has also a two-dimensional H2O/NH2 partial structure, similar to a subset of the three-dimensional network of the adduct NH3 H2O of analogous composition.
Zum Photoabbau von l-(4-Chlorphenyl)-4,4-dimethyl-3-(1H-1,2,4-triazoll- ylmethyl)-pentan-3-ol (Folicur®) [1] / On the Photodegration of l-(4-Chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazol-l-ylmethyl)-pentan-3-ol (Folicur®) [1]
Authors: Wamhoff Heinrich , Koch Helmut , Förster Rolf , Herrmann Christiane , Atta Sanaa M. S. , Mahran M. Refat , Sidky Mahmoud M.
Published: February 2015

The photodegradation of the 1,2,4-triazole fungicide Folicur 1 in different organic solvents (benzene, ether, methylene chloride, methanol) and water, in absence and in presence of a singlet oxygen sensitizer (methylene blue) has been studied. The photometabolites formed in organic solvents, have been separated by column chromatography (with isolation of 4 -7 , 13 and 14) and in the case of benzene as solvent as well with the aid of HPLC (isolated: 4 -7 , and five additional products 8-12). Photodegradation of 1 in water leads to the formation of only two photoproducts: 4 and 17 (separated only by HPLC). Identification has been achieved by spectroscopic methods and comparison (of retention times, UV and mass spectra) with authentic samples. Furthermore, the kinetics of the photodegradation of 1 in benzene and water (also after addition of titanium dioxide) has been established by HPLC-UV/VIS-technique. The interpretation of the kinetics allows conclusions towards the photodegradationmechanism, which is discussed in the paper. As expected, the addition of the photocatalyst titanium dioxide leads to a significant acceleration of the photodegradation.
Oxidsulfidchloride der Lanthanide vom Typ M4OS4Cl2 (M = La-Nd) / M4OS4Cl2-Type Oxysulfide Chlorides of the Lanthanides (M = La -Nd)
Authors: Schleid Thomas , Lissner Falk
Published: February 2015

Oxysulfide chlorides, M4OS4Cl2, of the lanthanides (M = La - Nd) are obtained upon the oxidation of the metals with sulfur in the presence of MOCl (or M2O3) and MCl3 in appropriate molar ratios. Additional NaCl or an excess of MCl3 serving as a flux provide even single crystalline material after reactions at 850 °C for seven days in sealed tantalum capsules. The crystal structure of M4OS4Cl2 (hexagonal, P63mc, no. 186, Z = 2; M = La: a = 933.19(3), c = 701.22(4) pm, c/a = 0.7514, R = RH = 0.020; M = Ce: a = 925.49(3), c = 694.13(3) pm, c/a = 0.7500; M = Pr: a = 919.72(4), c = 688.53(4) pm, c/a = 0.7486; M = Nd: a = 914.25(4), c = 683.12(4) pm, c/a = 0.7472, R = 0.022, Rw = 0.019) contains isolated O2--centered (M3+)4 tetrahedra which are surrounded by twelve S2- and six Cl-, capping vertices, edges, and faces of each tetrahedron and linking to other [OM4] units. Basically, the structure is identical to that of Ba4OCl6 if Ba2+ is substituted by M3+ and 2/3 of the CL- anions are replaced by S2- to secure charge neutrality in M4OS4Cl2. Different models for the Cl-/S2- replacement are presented on the basis of comparisons of the Madelung part of the lattice energy (MAPLE) with the MAPLE sum of the binaries (M2O3, M2S3, and MCl3).
Die Kristallstruktur von Gadolinium-(III)-hydrogensulfat Gd(H SO4)3 / Crystal Structure of Gadolinium-(III)-hydrogensulfate Gd(HSO4)3
Authors: Hummel Hans-Ulrich , Joeg Petra , Pezzei Gerhard , Wolski Alexander
Published: February 2015

Gd(HSO4)3 is obtained on treatment of Gd2(SO4)3 in conc. H2SO4 in closed vessels at 200 °C. The extremely moisture-sensitive crystals belong to the orthorhombic space group Pbca. Lattice constants are a = 12.080(8), b = 9.574(8), c = 16.513(8)Å and Z = 8.

Gadolinium is coordinated by eight oxygen atoms of the hydrogensulfate ligands forming a distorted square antiprism. There are three different HSO4
- anions within the structure. One of them is coordinated with two Gd atom s while two HSO4
- anions bridge three Gd atoms. The Gd-O bond lengths vary in the range of 2.334(6)-2.423(5)Å .
Synthese und Kristallstruktur von KCuHo2Mo4O16 / Synthesis and Crystal Structure of KCuHo2Mo4O16
Authors: Szillat Holger , Müller-Buschbaum Hanskarl
Published: February 2015

Single crystals of KCuHo2Mo4O16 have been prepared by recrystallisation from melts and investigated by X-ray diffractometer techniques. The compound crystallizes with monoclinic symmetry, space group C 2/c, a = 521.6(1), b = 1251.3(2), c = 1953.1(2) pm, β = 92.903(18)°, Z = 4. KCuHo2Mo4O16 represents a new structure type characterized by HoO8 and alternate CuO6/KO10 polyhedra chains. The connection of these polyhedra chains to each other and by MoO4 tetrahedra is described and the crystal structure discussed with respect to related compounds of the CuLnMo2O8 and KLnMo2O8 types.
Einfache Synthese von 2,2-Diethoxy-2,5-dihydrofuranen, 2(5 H)Furanonen und 2-Ethoxy-furanen.Kristall-und Molekülstruktur eines Barrelenon Diels-Aider Produktes [1] / Convenient Synthesis of 2,2-Diethoxy-2,5-dihydrofurans, 2(5 H)Furanones and 2-Ethoxyfurans.Crystal and Molecular Structure of a Barrelenone Diels-Alder Product [1]
Authors: Saalfrank Rolf W. , Hafner Wieland , Markmann Joachim , Welch Andreas , Peters Karl , Schnering Hans Georg von
Published: February 2015

Reaction of 1,2-hydroxyketones 5 with (2,2-diethoxyvinylidene)triphenylphosphorane (2) or (2,2-diethoxyvinyl)triphenylphosphonium tetrafluoroborates 6 yields the 2,2-diethoxy- 2.5-dihydrofurans 9. Depending on the reaction conditions used, the orthoesters 9 can be hydrolized to give 2(5 H)furanones 10 and 2-ethoxyfurans 11, respectively. 4,5-Dimethyl- 5.6-dihydro-2-pyranone (20) and 8-methoxycoumarin (23) are prepared, starting from (2,2-diethoxyvinyl)triphenylphosphonium tetrafluoroborate (6 a) and 1-hydroxy-2-methyl- 3-butanone (16) or 2-hydroxy-3-methoxy-benzaldehyde (21). The 2-ethoxyfuranes 11 readily undergo Diels-Alder reactions with 2-chloracrylonitrile (24), maleic anhydride (26), N-phenyl-1,2,4-triazoline-3,5-dione (28) and dimethyl acetylenedicarboxylate (30) to give the corresponding Diels-Alder products 25, 27, 29 and 31, respectively. Contrary to 2-ethoxyfuran 11b , 11a reacts with two equivalents of acetylene 30, to yield barrelenone 34. The structure of 34 unequivocally is established by X-ray structure analysis.
μ2-Chlorokomplexe von Succinimid und N-Chlorsuccinimid. Die Kristallstrukturen von PPh4[Cl(Succinimid)2], PPh4[[Cl(N-Cl-Succinimid)2] und N-Chlorphthalimid / μ2-Chloro Complexes of Succinimide and N-Chlorosuccinimide. The Crystal Structures of PPh4[Cl(Succinimide)2], PPh4[Cl(N-Cl-Succinimide)2] and N-Chlorophthalimide
Authors: Ghassemzadeh Mitra , Harms Klaus , Dehnicke Kurt , Magull Jörg
Published: February 2015

The donor-acceptor complexes PPh4[Cl(succinimide)2] and PPh4[Cl(N-chlorosuccinimide)2] have been prepared by reactions of PPh4Cl with succinimide and N-chlorosuccinimide, re­ spectively. in acetonitrile solutions. The complexes have been characterized by IR spectros­ copy and by crystal structure determinations. The crystal structure of N-chlorophthalimide has also been solved.
Complexing Ability of Some 2-Spirothiazolid-4-one Derivatives
Authors: El-Gahami Mohamed A. , El-Zohry Maher F.
Published: February 2015

The complexes of some 2-spirothiazolid-4-one derivatives have been prepared with Cu(II), N i(II), C o(II) and Cd(II) salts. The complexes all have a metal to ligand ratios of 1:1 or 1:2 and are all believed to have tetrahedral structures with chelating ligands. Their structures are suggested on the basis of analysis, X-ray diffraction techniques, spectral (UV-VIS, IR, 1H NMR), and thermal decomposition as well as conductivity measurements. The ligands are coordinated to the metal ions as monovalent bidentate ligands through the OCO groups. Electrical conductivity studies indicated that these complexes have activation energies in the range of semi-conducting materials. It is observed that some of the complexes are m ore potent as bacteriostatic agents than the free ligands.
Fusing Nickelocene and Cyclopentadiene by Two Silyl Bridges. Synthesis and 1H, 13C, and 29Si NMR Investigation of a Paramagnetic Building Block for High-Nuclear Metallocenes
Authors: Fritz Monika , Hiermeier Johann , Köhler Frank H.
Published: February 2015

Two isomers of tetrahydro-4,4,8,8-tetramethyl-4,8-disila-s-indacene (LH2) were monodeprotonated and treated with cyclopentadienyl anion and NiBr2(THF)1,5 to give a 72% yield of the mixed nickelocene CpNi(LH) where a cyclopentadiene is fused to a nickelocene. The analysis of the paramagnetic 1H, 13C, and 29Si NMR spectra demonstrated that the syn and anti isomer of CpNi(LH) formed in a ratio of 5/1. Both isomers could be deprotonated to yield the anion CpNi(L-). According to its 13C NMR spectrum the bridging ligand L is not planar