bluuebunny/crossref_metadata_2025 huggingface dataset:
Coordination of Rhodium(III) in Dilute Aqueous Solutions in Presence of Chloride Anion
Authors: Caminiti R. , Atzei D. , Cucca P. , Squintu F.
Published: February 2015

Dilute aqueous solutions of Rhodium (III) at the Cl1/Rh(III) ratios 4.86 and 10.7 have been X-ray examined. Octahedral Rh(H2O)6
3+ and Rh(H2O)3Cl3 complexes are the species which are consistent with the correlation functions and the structure functions. The average number of bonded chloride ions per Rhodium atom has been determined and the reliability of the structural information is critically examined.

The influence of the temperature on the substitution of water molecules by chloride ions is confirmed by using Raman spectroscopy.
Notizen: A High-Resolution Time-of-Flight Mass Spectrometer Using Laser Resonance Ionization
Authors: Frey R. , Weiss G. , Kaminski H. , Schlag E. W.
Published: February 2015

A resonance ionization time-of-flight mass spectrometer is presented and mass spectra are shown which demonstrate its analytical capability, i.e. the possibility of soft and hard ionization, the wavelength selectivity and the mass resolution of 6500 (50% valley) at mass 96, which is expected to increase much more at higher masses.
Notizen: Has Liquid Formamide a Linear-Chain Structure or Ring-Dimer Structure?
Authors: Ohtaki Hitoshi , Itoh Sumiko
Published: February 2015

The structure of liquid formamide is discussed on the basis of X-ray diffraction measurements and MO calculations. It is concluded that liquid formamide has both chain-like and ring-dimer moieties and that the former ones have a longer life time.
Zur spektroskopischen Analyse von Redoxgleichgewichten am Beispiel NAD(P)H-abhängiger Dehydrogenasen
Authors: Konstanczak J. , Polster J.
Published: February 2015

Equilibria of the form [xxx] can be analysed spectroscopically in a significant way by means of absorbance diagrams. Two methods are described for the determination of the equilibrium constant K. They are valid for different domains of K. For both methods the knowledge of the absorbance coefficients of C and D is not required. The determination of K is demonstrated in case of the enzyme catalysed redox reaction by β-hydroxybutyrate dehydrogenase: acetoacetic acid + NADH + H+ ⇄ β-hydroxybutyric acid + NAD+.
Changes in the Glass Forming Ability of MgZnSn Alloys Due to the Presence of an Intermetallic Compound
Authors: Mingolo M. , Arcondo B. , Nassif E. , Sirkin H.
Published: February 2015

X-ray and Mössbauer studies are performed on (Mg70Zn30)100-xSnx rapidly colled alloys with different tin contents. The third element (Sn) added to Mg70Zn30 modifies the glass forming ability (GFA) of the binary alloy. It is shown that this occurs because of the appearance of an intermetallic compound (Mg2Sn) that perturbs the crystallization of the remnant MgZn. The large affinity of the added element (Sn) to one of the components (Mg) appears to be the key to the improved GFA. Structural similarities were found between the obtained glass and amorphous Mg70Zn30.
Maxwell-Dirac-Isomorphism . XIII
Authors: Sallhofer Hans
Published: February 2015

On the history of wave mechanics.
A Diode Laser-Grating Study of the ν2 + ν5 Band of C2D2
Authors: Alanko S. , Paso R. , Anttila R.
Published: February 2015

The region of the ν2 + ν5 band of deuterated acetylene C2D2 around 2305 cm-1 has been studied using a diode laser-grating spectrometer. The grating spectrum covered the whole range o f the band. The structure of the Q branch as well as the Q branches o f the hot bands ν2 + 2ν5 ←ν5 and ν2 + ν4 + ν5 ← ν4 together with some special parts have been investigated with the diode laser, too. Molecular constants for the ν2 + ν5 band with small improvements in the ground state constants are presented. The hot bands were analyzed by taking the l-resonances into account.
Electrical Conduction in Trivalent Chromium and Nickel Molybdate
Authors: Gaur Kanchan , Lai H. B.
Published: February 2015

The electrical conductivity (σ) and Seebeck coefficient (S ) of trivalent chromium and nickel molybdate are measured at 500 -1200 K. On the basis of these data it is concluded that chromium molybdate undergoes a phase transition at 780 K and nickel molybdate at 740 K. log σ and S depend linearly on T-1 in certain temperature ranges. It is shown that the conduction mechanism in these solids is essentially of the band type in which the O2-:2p band is the valence band and M3+:4 s (transition metal 4 s band) the conduction band. Under simplifying assumptions the energy band gap and the mobility of the charge carriers are evaluated.
NM R T1-Analysis of Methyl Tunnelling in Molecular Crystals at Intermediate Barriers
Authors: Langen H. , Montjoie A.-S. , Müller-Warmuth W. , Stiller Hildegard
Published: February 2015

The frequency and temperature dependences of the 1H NMR relaxation rates T1
-1for rotating CH3 groups in solids look quite anomalous at intermediate hindering potential barriers. In order to explain the experimental behaviour and to extract parameters from the NMR T1 experiments that account for tunnelling at low temperatures and random reorientation at elevated temperatures, we have calculated T1
-1vs. T-1 curves to be expected under various conditions. New experimental results for methyl iodide, methyl bromide, 3-methylthiophene, p-xylene, and methyl isocyanate have been fitted by this procedure and all the parameters that describe the motional behaviour have been derived. The single particle rotational potential has been determined using the first two terms of the Fourier expansion.
Microwave and Millimeterwave Spectrum of Monofluoracetonitrile-15N (CH2FC15N). A Contribution to Molecular Structure
Authors: Zerbe H. , Guarnieri A.
Published: February 2015

The microwave and millimeterwave spectrum of 15N-fluoracetonitrile(CH2FC15N) in the ground vibrational state are investigated in the region between 8 and 150 GHz. The measured transitions are fitted to a Hamiltonian with three rotational constants, five quartic and seven sextic centrifugal distortion constants in the symmetric top limit of van Eijck-Typke and in the s-reduction of Watson. The rotational constants are used to improve the calculated r0 -restructure of the fluoracetonitrile molecule.
Photophysical and Photochemical Studies of Polycyclic Aromatic Hydrocarbons in Solutions Containing Tetrachloromethane II. The Solvent Effect on the Fluorescence Quenching of Aromatic Hydrocarbons by Tetrachloromethane
Authors: Wiczk Wiesław M. , Latowski Tadeusz
Published: February 2015

Fluorescence quenching of aromatic hydrocarbons in a large concentration range of the quencher has been studied in a variety of two-component mixtures of tetrachloromethane with other solvents. In aliphatic solvents the process could be described by the Stern-Volmer equation, whereas in the remaining mixtures the fluorescence quenching curves showed a parabolic behaviour which has been explained in terms of specific interactions between the components of the mixtures.
207Pb and 205Tl NMR on Perovskite Type Crystals APbX3 (A = Cs, Tl, X = Br, I)
Authors: Sharma Surendra , Weiden Norbert , Weiss Alarich
Published: February 2015

By 205Tl and 207Pb NM R the chemical shift in polycrystalline samples of binary halides AX, BX2 and ternary halides ABX3 (A = Cs, Tl; B = Pb; X = Br, I) was studied at room temperature. The chemical shift tensors δ ( 205Tl) and δ (207Pb) were determined in magnitude and orientation on single crystals of the orthorhombic TlPbI3. The components of the δ(205Tl) tensor are δx (205Tl) || a = 611ppm; δy (205Tl) || b = 680 ppm; δZ(205Tl) || c = 1329 ppm; δiso(205Tl) = 873.3 ppm (with respect to 3.4 molar aqueous solution of TlOOCCH3). The chemical shift tensor of 207Pb in TlPbI3 shows two orientations. One of them is: δx (207Pb) = 3760 ppm, inclined 30° from b towards c, δy(207Pb) || a = 3485 ppm, δz(207Pb) = 2639 ppm inclined 120° from b towards c. δiso(207Pb) = 3295 ppm (with respect to saturated aqueous solution of Pb(NO3)2). The results are discussed with respect to the crystal structure and a model to explain orientation and anisotropy of the tensors δ(205Tl) and δ(207Pb) in TlPbI3 is proposed.

In the system CsPbBr3-x Ix δ(207Pb) was studied on polycrystalline samples. The chemical shift increases with increasing x and negative excess shift is observed.
Phase Diagram Studies on the Al- Ni System
Authors: Hilpert K. , Kobertz D. , Venugopal V. , Miller M. , Gerads H. , Bremer F. J. , Nickel H.
Published: February 2015

The Al-Ni phase diagram has been investigated in the com position range xNi = 0.70 to 0.97. Phase boundaries were determined by using differential thermal analysis and Knudsen effusion mass spectrometry. The measurements were carried out in the temperature range between 1409 and 1730K. An Al-Ni phase diagram is obtained for xNi ≧ 0.70 by combining the data from this work with selected data from the literature. This diagram deviates from that recommended by phase diagram compilations and used generally in the literature to date; it agrees reasonably well with a diagram which has been rejected in the literature.
Excitation Energy Transport and Concentration Depolarization of Donor Fluorescence in Two-Component Viscous Solutions
Authors: Bojarski C. , Kawski A. , Kubicki A. , Żurkowska G.
Published: February 2015

The concentration depolarization of the fluorescence of rhodamine B (donor) in the presence of malachite green (acceptor) was investigated in a glycerol-ethanol mixture with constant ratios of the reduced concentrations of the donor and acceptor (system I: γD/γA = 1, system II: γD/γA = 19). A marked effect of the configuration of the active molecules surrounding the successively excited donors upon the emission anisotropy was found in system I, having strong fluorescence quenching and weak migration, whereas in system II, with strong migration and weak fluorescence quenching, this effect is smaller. The results are discussed based on the up-to-date theories of the concentration depolarization of fluorescence.
EPR of VO2+ in the Mineral Wavellite Al3(OH)3(PO4)2 · 5H2O
Authors: Vassilikou-Dova A. B. , Landrath K. D. , Lehmann G.
Published: February 2015

In wavellites from two different localities EPR spectra of VO2+ ions were detected and analyzed. The most prominent center was axial within the limits of error with g = 1.932, gxx = gyy = 1.948, Azz = 171.8 and Axx = Ayy = 54.7 (A in 10-4 cm). The orientation of the z-axis proves that the Al - OH group with the shortest AI - O bond is substituted by the VO2+ ion. Additional spectra of much lower relative intensity with different orientation of their z-axes can also be assigned to certain Al - O combinations.
High-Resolution Infrared Spectrum of Diazirine, H2CN2. Rovibrational Analysis of the Methylene Deformation Band
Authors: Gambi A. , Baldacci A. , Giorgianni S.
Published: February 2015

The infrared spectrum of diazirine has been recorded at Doppler resolution with a high informa­tion Fourier transform spectrometer. The ν3 fundamental has been reinvestigated and the overall assignment of the rovibrational transitions has been carried out. From the least-squares analysis a more accurate set of molecular constants including the sextic centrifugal distortion constants has been determined for the level υ3 = 1 and will be reported here. The higher resolution achieved here allowed the assignment of weaker lines and many Q branch transitions. Moreover many blended lines have now been resolved and could be properly assigned.
Gravitation as a Composite Particle Effect in a Unified Spinor-Isospinor Preon Field Model I
Authors: Stumpf H.
Published: February 2015

The model is defined by a selfregularizing nonlinear preon field equation, and all observable (elementary and non-elementary) particles are assumed to be bound (quantum) states of fermionic preon fields. Electroweak gauge bosons, leptons, quarks, gluons as preon composites and their effective dynamics etc. were studied in preceding papers. In this paper gravitons are introduced as four-preon composites and their effective interactions are discussed. This discussion is performed by the application of functional quantum theory to the model under consideration and subsequent evaluation of a weak mapping procedure, both introduced in preceding papers. In the low energy limit it is demonstrated that the effective graviton dynamics lead to the complete homogeneous Einstein equations in tetrad formulation.
Exact Analytical Solutions of the Non Polynomial Oscilator
Authors: Roy Pinaki , Roychoudhury Rajkumar
Published: February 2015

We derive new exact (analytical) solutions of the non polynomial oscillator V(x) = x2 + λx2 / (1 + g x2) in one as well in three dimensions. The solutions are derived within the framework of supersymmetric quantum mechanics, and it is shown that exact solutions exist when the coupling constants satisfy a supersymmetric constraint.
Vector Theory of Gravity with Substratum
Authors: Winterberg F.
Published: February 2015

A vector theory of gravity with substratum is proposed, which reproduces all the empirically verified linear and nonlinear predictions of Einstein's gravitational field equations, but unlike Einstein's theory, it does not lead to the unphysical singularities and causality-violating solutions permitting travel back in time. In the proposed alternative theory, a substratum or ether is the cause of all relativistic effects, and for this reason is assumed to obey a nonrelativistic equation of motion, an assumption which allows the substratum to consist of densely packed positive and negative Planck mass particles. A substratum of this kind can produce the vacuum fluctuations, needed to be in agreement with the empirical evidence, but avoids the paradox of infinite gravitationl forces, predicted by a divergent zero point energy, the only one possible under the strict adherence to the kinematic interpretation of special relativity.
Tensorial Representation of ƒ′ for Nb in Lithium-niobate, LiNbO3
Authors: Petcov A. , Kirfel A. , Fischer K.
Published: February 2015

Using Synchrotron radiation, the dependence of resonant phenomena (absorption, fluorescence and Raman scattering) on the angle between the polarisation plane of the incident radiation and the polar c-axis in ferroelectric Lithium-niobate, LiNbO3, was studied in the vicinity of the Nb K-absorption edge. Applying the "optical theorem", the observed dipolar anisotropics can be explained in terms of the projection of the dipole momentum operator on the polarisation vector of the X-ray photons.
Nonlinear Thermodynamics of Moving Material Surfaces in Electric Fields
Authors: Wallschlager H.
Published: February 2015

A continuum-mechanical formalism is presented for the phenomenological description of moving, curvilinear, material surfaces in electric fields in interaction with volume-phases. In addition to conventional equations (balance and constitutive laws) the explicit use of relations for the surface geometry is introduced. A method to establish nonlinear constitutive equations by tensorial and thermodynamical considerations is proved to be applicable to two-dimensional continua. The resulting equations for boundaries interacting with adjacent volumes are of practical importance for the selfconsistent calculation of boundary values. The physical meaning of the different relations is discussed.
Calculation of the Excitation Energies of a Hydrogen Impurity in Niobium
Authors: Sommer F. T. , Hau K. , Frodl P. , Wahl F.
Published: February 2015

Recent calculations of the electronic structure of a hydrogen atom in niobium using microscopic first principles are extended in that the dynamical behaviour of a hydrogen impurity centre in Nb is considered quantummechanically. The calculated excitation energies are in good agreement with experimental values of time of flight-spectra taken from NbH0.05.
Reaction of Bromous Acid with Bromide in the Presence of Silver Ions
Authors: Försterling H. D. , Schreiber H.
Published: February 2015

The reaction HBrO2 + Br- + H + →2 HOBr, which is the most important control reaction in the Belousov-Zhabotinsky (BZ) system, is investigated in competition to the AgBr precipitation reaction Ag+ + Br- →AgBr. It turns out that the bromite-bromide reaction starts even in the presence of Ag+ in high concentration; the rate of consumption of bromite by bromide, however, is slowed down significantly if silver ions are present in the system. The experiments reveal that the AgBr precipita­ tion reaction proceeds in a series of several steps, starting with a fast equilibrium. This way different experimental results on the influence of silver ions on the kinetics of the BZ reaction may now be better understood.
Thermoanalytische Untersuchungen zur Rückoxidation von Ba2YCu3O6+x
Authors: Teske Chr. L. , Müller-Buschbaum Hk.
Published: February 2015

The reoxidation reaction of Ba2YCu3O6+ x forming the superconducting ceramic material Ba2YCu3O6 93 is studied by thermoanalytical methods (DTA and TG). The exothermal oxygen uptake in pure O2-atmosphere is at a maximum rate in the range of 230-330 °C (≈ 150min). The reoxidation temperature can be lowered by treatment of Ba2YCu3O6 0 in Ar : H2 = 1: 1 atmosphere but the uptake of greater amounts of hydrogen prevents the material from becoming super-conducting again at low reoxidation temperatures. The process has an activation energy Ea = 70.9 ± 2kJ Mol and a reaction enthalpy ΔH = - 86.7kJ/Mol Ba2YCu3O6.0 (normalized to a 1/2 O2 basis) which is estimated from DTA-data.
The Iodine Hvperfine Structure in the Microwave Spectrum of Ethyl Iodide: Nuclear Quadrupole and Spin Rotation Coupling
Authors: Gripp Joachim , Dreizler Helmut
Published: February 2015

Some rotational transitions of ethyl iodide, CH3CH2I, have been reinvestigated by microwave Fourier transform (MWFT) spectroscopy. The iodine hyperfine structure splittings were first ana lyzed using a direct diagonalization procedure of the complete quadrupole Hamiltonian matrix. The results of this analysis showed deviations from our measurements up to 60 kHz. A new analysis using additional spin rotation coupling matrix elements reproduces our measurements within the experi­mental error limit and decreases the standard deviation of the least squares fit from 28 kHz to only 4 kHz.
35Cl Nuclear Quadrupole Relaxation in Pyridinium Hexachlorostannate (IV)
Authors: Tai Yutaka , Ishikawa Atsushi , Horiuchi Keizo , Asaji Tetsuo , Ikeda Ryuichi
Published: February 2015

The temperature dependence of the 35Cl quadrupole spin-lattice relaxation time T1Q is reported for the three known resonance lines of pyridinium hexachlorostannate (IV). With increasing temper­ature, a sharp decrease of T1Q is observed below the phase transition temperature of 331 K. This decrease can be explained by reorientational motions of the complex anions. The activation energy for the motions is determined as 97 and 63 kJmol-1 from the T1Q data obtained from the highest-frequency resonance line and the remaining two lines, respectively. The two different barriers observed for the reorientation of a single anion suggest the existence of anisotropy of the anionic motion. An anomalous T1Q vs. T-1 relation observed in an intermediate-temperature region is discussed by referring to the cationic motion.
On the Stability of Axisymmetric MHD Modes
Authors: Lortz D.
Published: February 2015

The stability of axisymmetric ideal MHD equilibria which are symmetric with respect to the equatorial plane is considered. It is found that for external axisymmetric modes which are antisymmetric with respect to the equatorial plane and for profiles such that the current density vanishes at the free plasma boundary the stability problem reduces to a classical interior-exterior scalar eigenvalue problem. Because of the separation property the resulting stability condition is necessary and sufficient and is thus more stringent than criteria derived by choosing special test functions, e.g. the vertical shift condition.
Spin-Lattice Relaxation of Water in Cement Gels
Authors: Blinc R. , Dolinšek J. , Lahajnar G. , Sepe A. , Zupančič I. , Zumer S. , Milia F. , Pintar M. M.
Published: February 2015

The time evolution of the magnetization relaxation recovery of exchangeable water in ordinary Portland cement and white cement have been studied as functions of the hydration time together with the temperature and Larmor frequency dependence of the proton spin-lattice relaxation rates. The water self-diffusion coefficient was also studied as a function of both the hydration time and the diffusion time. The results show that the exchangeable water relaxes via cross relaxation to the gel protons, which are in turn relaxed via spin diffusion to paramagnetic impurities. The roughness of the gel-water interface and the wide distribution of pore sizes result in a stretched exponential nuclear magnetization relaxation recovery with the exponent reflecting the fractal geometry of the hydrating cement gel.
Hydrogen in Electrodynamics. I. Preliminary Theories
Authors: Sallhofer Hans
Published: February 2015

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.
Ionic conductivity and electric relaxation in the poly(NN-dimethylacrylamide)-LiClO4 system
Authors: Mellander B.-E. , Stevens J. R.
Published: February 2015

The poly(NN-dimethylacrylamidc)-LiClO4 system has been investigated regarding ionic conduc­tivity and electric relaxation. This material may contain up to 29 mol% LiClO4 while still being an amorphous and transparent ionic conductor. The conductivity for this composition is of the order of 10-9 (ohm cm)-1 at room temperature while it increases to 7 ·10-7 (ohm cm)-1 at 100 °C. The activation energy according to the conductivity measurements is 1.1 eV. The system polymethyl­methacrylate)-LiCF3SO3 was also investigated but only very low ionic conductivities were detected.
Short Range Order in Structural Models for the Amorphous Fe80B20- and Ni81B19-Alloys
Authors: Kizler P. , Lamparter P. , Steeb S.
Published: February 2015

The short range order in several structural models for amorphous alloys is investigated with respect to pair correlation functions, bond angle distributions and other properties. Despite of the different principles of modelling, the topological short range order turned out to be almost identical. Therefore also the question for the triplet correlations to some extent is found solved. Remaining differences thus consist regarding more complex correlations among the atoms.
Variations of the Partial Short Range Order Structure of Amorphous Ni32Pd52P16 During Relaxation Using Neutron Diffraction and Isotopic Substitution
Authors: Schaal M. , Lamparter Ρ. , Steeb S.
Published: February 2015

Melt spun amorphous Ni32Pd52P16 specimens were produced using natNi, the isotope 60Ni, and an isotopic mixture ∅Ni with zero-scattering length. The specimens were heat treated for two hours at 496, 533, 570, and 607 K, respectively, and investigated by neutron diffraction. The Faber-Ziman structure factors as well as the total pair correlation functions show rather large effects caused by the relaxation procedure. By convenient combination of the total functions conclusions on the behaviour of the Ni-Ni, Ni-Pd, Ni-P, Pd-Ni, Pd-Pd, Pd-P, P-Ni, and P-Pd partial coordina­tion numbers and atomic distances during the relaxation procedure are obtained. Relaxation has no detectable influence on the nearest neighbourhood but leads to variations in the region of the second Ni-Ni coordination sphere (3.7 Å ≦ R ≦ 5.7 Å) with the main effect that after heat treatment at 607 K, 2 h, the second Ni-Ni coordination sphere is subdivided into three distinct subspheres. It is suggested that the relaxation process mainly involves the redistribution of bond angles.
Self-Exchange Velocities in Molten Equimolar Li(Cl, Br) Predicting an Anion Chemla Effect
Authors: Baluja Shipra , Endoh Akira , Okada Isao
Published: February 2015

A molecular dynamics simulation of an equimolar mixture of LiCl and LiBr melts has been performed at about 1000 K to evaluate the self-exchange velocities (SEV). The SEV of Li+ - Br- pairs is greater than that of Li+-Cl- pairs. Therefore in this mixture the mobility of Br- ions may be greater than that of Cl- ions, that is, an “anion Chemla effect” may occur. For comparison. MD simulations of pure LiCl and LiBr melt|s have also been performed.
Notizen: Fast Pulsed Laser Induced Electron Generation for Electron Impact Mass Spectrometry
Authors: Rohwer E. R. , Beavis R.C. , Köster C. , Lindner J. , Grotemeyer J. , Schlag E. W.
Published: February 2015

A new ultra fast electron impact (El) ion source is pre­sented that produces a very short, high intensity electron beam, allowing medium resolution mass spectra to be re­corded without pulsing the ion accelerating voltages in a time-of-flight mass spectrometer (TOF-MS). The ion source requires minimum modification of any TOF-MS equipped with an electrostatic ion reflector and UV-laser. El-spectra are presented for comparison with literature spectra.
Investigation in the Vicinity of the Critical Point
Authors: Yukhnovskii I. R.
Published: February 2015

It is shown that the events occuring in the vicinity of the critical point can be described in full by means of the collective variables with the appropriate reference system. The partition function containing the explicit form for the quartic measure density is obtained and integrated. Expressions for the critical temperature, critical density and critical chemical potential surfaces are calculated.
Interionic Potentials and MC Simulations of Molten AgCl
Authors: Margheritis C. , Sinistri C.
Published: February 2015

Monte Carlo simulations on molten AgCl were carried out in order to test the applicability of the interionic potentials recently proposed for this salt in the solid phase. None of the literature potentials can be used as such: in all cases pairs of like ions reach too short distances of approach causing the collapse of the system. It was proved that, in order to obtain equilibration of the system, the pair potentials of like ions must be recalculated.

On the basis of these modified potentials, MC simulations of molten AgCl were carried out at 728 (m.p.), 1000 and 1500 K. The polarization energy effect was also analyzed with the use of a soft ion model.
Acetonitrile-Water Solutions of Sodium Halides: Viscosity and Self-Diffusion of CH3CN and H2O
Authors: Hawlicka Ewa
Published: February 2015

Measurements of the viscosity of solutions of NaCl and Nal in acetonitrile-water mixtures at 25 °C, and of the self-diffusion coefficients of CH3CN and H2O in these liquids, using 14C and 3H as tracers, are reported. The results confirm the previously postulated preferential solvation of the ions by acetonitrile.
Synthesis, Structure, and Spectral Properties of Pvrylium Salts and Their Derivatives. II.5-(Benzyliden)- and 5-(Cinnamvliden)-5,6,7,8-Tetrahydro-1,3-Diphenyl-2-Benzopyrylium Salts
Authors: Nikolov P. , Deligeorgiev T. , Tyutyulkov N. , Kanev I.
Published: February 2015

The synthesis, structure and spectral properties of a group of dyes with a pyrylium ring are described. Quantumchemical calculations indicate that the chromophore system has a structure corresponding to that of the polymethine dyes.
A Monte Carlo Study on a Magnesium Cyclen Complex
Authors: Ruangpornvisuti Vithaya W. , Rode Bernd M.
Published: February 2015

A Monte Carlo simulation has been performed to study the hydration of the magnesium complex of 1,4,7,10-tetraazacyclododecane (cyclen). An intermolecular potential function for magnesium cyclen complex and water, derived from ab initio calculations was used. The first hydration shell results to consist of 18 water molecules.
Dielectric Relaxation Study of ZnCl2 and ZnBr2 Solutions in Water/DMSO Mixtures
Authors: Galstian A. , Stockhausen M.
Published: February 2015

Dielectric spectra have been measured for the title systems up to 72 GHz at 20 °C with salt concentrations ≤ 1 mol/l. The results are described by a superposition of Debye terms. Two terms are sufficient for binary water/DMSO mixtures, while two additional lower frequency ones are required when salt is added. The results for both halides differ only little. The relaxation strengths of a term ascribable to ionic complexes and a term ascribable to water/DMSO (2:1) complexes vary in opposing sense, demonstrating the competition between those complexes.
PVT Measurements on 4′-n-Octyl-Biphenyl-4-Carbonitrile (8CB) up to 300 MPa
Authors: Sandmann M. , Würflinger A.
Published: February 2015

P, Vm , Tdata have been measured for the smectic, nematic and isotropic phases of 4'-n-octyl-biphen-yl-4-carbonitrile (8CB) in the temperature range 300-370 K and pressures up to 300 MPa. At atmospheric pressure all phase transitions appear to be of first order due to a discontinuity in the density. The volume change at the smectic A -nematic transition is only a tenth of the volume change at the clearing temperature. At moderate pressures below 80 MPa the SA -N transition could be detected as a discontinuity in the period of oscillation in measurements with a high-pressure vibrating tube densimeter. At higher pressures the discontinuity seems to die away, possibly indicating a change from first order to second order transition. From the volume changes and the slopes of the transition lines we calculate the enthalpy changes at the phase transition. The p, Vm , T data enable us to calculate the volume part of the entropy and the molecular field parameter γ=δln TNI/δln VNI .
New Exact Solutions for a Generalized Breaking Soliton Equation
Authors: Gao Yi-Tian , Hong Woopyo , Tian Bo
Published: February 2015

The breaking soliton equations are a class of nonlinear evolution equations of broad interest in physical and mathematical sciences. In this paper, the application of the generalized tanh method with symbolic computation leads to new exact solutions for a generalized breaking soliton equation, of which the previously-obtained solutions are the special cases.
A Comparison of the Enamino Carbonyl Conjugation Efficiency for Hydrogen Bonding Formation in Pyridone and Dihydropyridone Systems
Authors: Borowiak Teresa , Wolska Irena , Korzański Artur , Milius Wolfgang , Schnick Wolfgang , Antkowiak Wiesław
Published: February 2015

The crystal structures of two compounds containing enaminone heterodiene systems and forming intermolecular hydrogen bonds N-H·O are reported: 1) 3-ethoxycarbonyl-2-methyl-4-pyridone (hereafter ETPY) and 2) 3-ethoxycarbonyl-2-phenyl-6-methoxycarbonyl-5,6-di-hydro-4-pyridone (hereafter EPPY). The crystal packing is controlled by intermolecular hydro­ gen bonds N-H·O = C connecting the heteroconjugated enaminone groups in infinite chains. In ETPY crystals the intermolecular hydrogen bond involves the heterodienic pathway with the highest π-delocalization that is effective for a very short N·O distance of 2.701(9) Å (average from two molecules in the asymmetric unit). Probably due to the steric hindrance, the hydrogen bond in EPPY is formed following the heterodienic pathway that involves the ester C = O group, although π-delocalization along this pathway is less than that along the pyridone-part pathway resulting in a longer N·O distance of 2.886(3) Å
Untersuchungen zur Thermolyse von Si2OCl6 / Thermolysis of Si2OCl6
Authors: Wilkening Andreas , Binnewies Michael
Published: February 2015

The thermolysis of gaseous Si2OCl6 leads to a mixture of higher chlorosiloxanes with up to 8 silicon atoms per molecule. The unexpected formation of larger molecules from smaller ones by high temperature pyrolysis is due to three basic reactions: a) Formation of highly reactive O = SiCl2 as an intermediate, b) insertion of O= SiCl2 into Si-Cl bonds (growth reaction), and c) thermally induced elimination of SiCl4 from chlorosiloxanes formed in (b). Temperature and time dependencies of the thermolysis have been investigated and are discussed
Preparation and Crystal Structure of Na4TiSe4. A Selenotitanate with Discrete Tetrahedral Anions
Authors: Klepp Kurt O.
Published: February 2015

Red crystals of Na4TiSe4 were obtained by reacting an intimate mixture of Na2Se, Ti and Se at 750°C. Na4TiSe4 is monoclinic, space group I2/a with a = 24.027(6), b = 7.346(4), c = 21.572(6) Å, (β = 104.52(2)°, Z = 16. Its crystal structure was determined from diffractometer data (AgK α-radiation) and refined to a conventional R of 0.036 for 2673 F0′s and 158 variables. The crystal structure is of a new type, characterized by the presence of discrete tetrahedral complex anions, [TiSe4]4- , which are arranged in slabs parallel to (100). The average Ti-Se bond length is 2.385(1) Å. The Na+ cations are in different chalcogen environments with distorted octahedral, square pyramidal or planar configurations, respectively
A Novel Synthesis of Sulfone Systems as Antimicrobial Agents
Authors: Erian Ayman W. , Issac Yvette A. , Sherif Sherif M.
Published: February 2015

The applicability and synthetic potency of novel reagent, 2-aryl-1,1-dicyano-3-(phenylsulfo-nyl)propenes 3 to develop an expeditious convenient synthetic route of unique polyfunctionally substituted carbocyclic and heterocyclic sulfone systems is reported. Chemical and spec­troscopic evidence for the structures of the newly synthesized compounds are described. Some of the obtained compounds were tested for their antimicrobial activity
Synthesis and Crystal Structures of ATi[Nb6Cl18] Compounds (A = K, Rb, Cs, In, Tl)
Authors: Nägele A. , Anokhina E. , Sitar J. , Meyer H.-J. , Lachgar A.
Published: February 2015

New quaternary niobium cluster chlorides corresponding to the general formula ATi[Nb6Cl18] (A = K, Rb, Cs, In, Tl) have been synthesized in sealed quartz tubes at 720 °C, starting from stoichiometric amounts of NbCl5, niobium metal, TiCl3, and ACl (A = K, Rb, Cs), or In or Tl metals. The structures of RbTi[Nb6Cl18] and CsTi[Nb6Cl18] were determined using single­ crystal X-ray diffraction. RbTi[Nb6Cl18] crystallizes in the rhombohedral crystal system, space group R3̄ (no. 148), Z = 3, with lattice parameters: a = 9.163(4), c = 25.014(14) Å (hexagonal setting). The structure refinement converged to R1 = 0.044 and wR2 = 0.058 for all data. In this structure, discrete [Nb6Cl18]4-cluster units are linked by Rb+ and Ti3+ cations, located in a 12-coordinated anticubeoctahedral and octahedral chloride coordination environment, respectively. In contrast, CsTi[Nb6Cl18] crystallizes in the trigonal crystal system, space group P3̄1c (no. 163), Z = 2. The lattice parameters were determined to be a = 9.1075(6), c = 17.0017(8) Å. The structure refinement gives the reliability factors R1 = 0.029 and wR2 = 0.063 for all data. The structure is built up of discrete octahedral [Nb6Cl18]4- cluster units, linked by Cs+ and Ti3+ cations which are located in a distorted hexagonal antiprismatic and octahedral chloride coordination environment, respectively. The structures of the compounds ATi[Nb6Cl18] (A = K, In, Tl) were found to be isotypic with RbTi[Nb6Cl18], and their unit cell parameters were refined using X-ray powder diffraction analysis.
Synthesis, Multinuclear (1H, 13C and 17O ) Magnetic Resonance Spectroscopy and Conformational Analysis of Some Substituted Aryl Naphthoates
Authors: Jios Jorge L. , Duddeck Helmut
Published: February 2015

The synthesis of 16 title compounds and their NMR spectroscopic properties is described. The spectra reveal evidences of the preferred conformation (acetyl group orientation and non-coplanarity) of the aroyl moieties.
The Inclusion of Carbon Disulfide in p-tert-Butylcalix[4]-and [6 ]arene - A Combined Crystallographic and Vibrational Spectroscopic Study
Authors: Schatz Jürgen , Schildbach Frank , Lentz Axel , Rastätter Sylvia , Schilling Joachim , Dormann Jörg , Ruoff Andreas , Debaerdemaeker Tony
Published: February 2015

The inclusion complexes formed from carbon disulfide and p-tert-butylcalix[4]arene ( 1·CS2) or p-tert-butylcalix[6]arene (2·CS2) were investigated by X-ray crystal structure analysis, infrared (IR) and Raman spectroscopy. The complex 1·CS2 crystallises in the space group P4/n, 2·CS2 in the space group P21/n. In case of p-tert-butylcalix[4]arene as host the carbon disulfide molecule is included in the cavity. In the crystal structure of p-tert-butylcalix[ 6]arene clathrate, self-complexation of one tert-butyl group in the cavity of another calix[ 6]arene can be observed. Due to inclusion, the symmetry of CS2 is lowered both in the p-tert- butylcalix[4]arene and p-tert-butylcalix[6]arene case causing significant shifts in the fully assigned infrared and Raman spectra.
Solid-State 29Si VACP/MAS NMR Studies of Silicon-Accumulating Plants: Structural Characterization of Biosilica Deposits
Authors: Bertermann Rüdiger , Tacke Reinhold
Published: February 2015

A series of silicon-accumulating plants [different Equisetum (horse tail) species, Echium vulgare, and Symphytum officinale] were studied by solid-state 29Si NMR experiments. For this purpose, selected parts of these plants were freeze-dried and then investigated by solid-state 29Si VACP/MAS NMR spectroscopy. The 29Si NMR spectra of these plants are quite similar and exhibit the typical pattern characteristic of polysilicic acid (amorphous silica).
Synthesis, Spectroscopic Investigation, and Theoretical Study of the Ruthenium Diazide Complex [Ru(tpy)(PPh3)(N3)2]
Authors: Seok Won K. , Yim Sun B. , Lee Heung N. , Klapötke Thomas M.
Published: February 2015

The reaction of [Ru(tpy)(PPh3)(Cl)2] (tpy = 2,2′:6′,2″-terpyridine) with sodium azide in acetone/water afforded [Ru(tpy)(PPh3)(N3)2]. The new Ru-diazide complex was fully characterized by elemental analysis, IR, Raman, and multinuclear NMR spectroscopy. The structures, energies and vibrational frequencies of the ruthenium diazide isomers, cis- and trans- [Ru(tpy)(PMe3)(N3)2] (Me=CH3), were calculated at the semi-empirical ZINDO/1 level of theory.
Darstellung, 11-NMR- und Schwingungsspektren von Mononitrooctahydrocloso- nonaborat(2-) und Monoaminooctahydro-closo-nonaborat(2-) sowie Kristallstruktur von (Ph4P)2[1-(NO2)B9H8]*CH3CN / Synthesis, 11B NMR and Vibrational Spectra of Mononitrooctahydro-closo-nonaborate( 2-) and M onoam inooctahydro-closo-nonaborate(2-) and Crystal Structure of (Ph4P)2[1-(NO2)B9H8]*CH3CN
Authors: Siegburg K. , Preetz W.
Published: February 2015

By electrochemical oxidation of (n-Bu4N)2[B9H9] in the presence of nitrite ions and the base DBU in dichloromethane solution [1-(NO2)B9H8]2- is formed. X-ray diffraction analysis has been performed on a single crystal of (Ph4P)2[1-(NO2)B9H8] · CH3CN (monoclinic, space group P21 a = 10.643(5), b = 32.661(5), c = 13.924(5) Å, β = 96.68°, Z = 4). By reduction of [1-(NO2)B9H8]2- with FeSO4 in aqueous alkaline solution the amino derivative [1-(NH2)B9H8]2- is formed. The UB NMR spectra of both compounds are consistent with a monosubstituted tricapped trigonal prism. The IR and Raman spectra exhibit characteristic BB, BH, NO and NH vibrations, respectively.
Darstellung und Kristallstruktur von (n-Bu4N)[ReBr5Py] / Synthesis and Crystal Structure of (n-Bu4N)[ReBr5Py]
Authors: Malottki B. v. , Preetz W.
Published: February 2015

By reaction of (n-Bu4N)2[ReBr6] with pyridine and (n-Bu4N)BH4 in dichloromethane various bromo-pyridine-rhenium(III) complexes are formed which can be separated by chromatography. Electrochemical oxidation of (n-Bu4N)2[ReBr5Py] leads to (n-Bu4N)[ReBr5Py]. X-ray structure determination on a single crystal has been performed of (n-Bu4N)[ReBr5Py] (monoclinic, space group P21/n a = 11,248(5), b = 17,192(5), c = 15,206(5) Å, β = 97,600(5)°, Z = 4).
Some New Luminescent Compounds Based on 4-Methylbenzylamine and Lead Halides
Authors: Papavassiliou G. C. , Mousdis G. A. , Raptopoulou C. P. , Terzis A.
Published: February 2015

Compounds of the general formula (CH3NH3)n-1(CH3C6H4CH2NH3)2PbnX3n+1, where X = I, Br, Cl and n= 1,2, 3,..., were prepared and characterized analytically and spectroscopically. Moreover, (CH3C6H4CH2NH3)2PbX4 and (CH3NH3C6H4CH2NH3)2Pb2I7 were characterized by X-ray crystal structure analysis. Their optical absorption and photoluminescence spectra exhibit excitonic bands, even at room temperature.
Zu Strängen assoziierte Ionen [AsCl4· AsCl3]- im [Mg(NCCH3)6][As4Cl14] / Strands of Associated [AsCl4· AsCl3]- Ions in [Mg(NCCH3)6][As4Cl14]
Authors: Rabe Susanne , Müller Ulrich
Published: February 2015

The reaction of arsenic, MgSO4 and S2Cl2 in acetonitrile yielded the title compound along with 4,5- dichloro-1 ,2,3-dithiazolium chloride, [C2NS2Cl2]Cl (which was formed from the solvent and S2Cl2). The crystal strucutre of [Mg(NCCH3)6][As4Cl14] was determined by X-ray diffraction. It is triclinic, space group P1¯, Z = 2, R = 0.049. The Mg2+ ion is coordinated by six acetonitrile ligands. The anions consist of AsCl4- and AsCl3 units which are associated to chains along the a axis by As ··· Cl contacts. Each As atom has distorted octahedral coordination.
Zur Koordinationschemie des 2,2′-Dipyridyldiselenids (PySeSePy), Teil 2 [1] Komplexe mit Mangan, Kupfer und Zink/ The Coordination Chemistry of 2,2′-Dipyridyldiselenide (PySeSePy), Part 2. Complexes with Manganese, Copper and Zinc
Authors: Kienitz Carsten O. , Thöne Carsten , Jones Peter G.
Published: February 2015

The coordination chemistry of 2,2′-dipyridyldiselenide (PySeSePy) towards mangane­se, copper and zinc centres has been studied. The complexes [MnBr2-N,N′-(PySeSePy)] (1), [CuBr2-N,N′-(PySeSePy)] (2), [Cu-(μ-Br)-N,N′-(PySeSePy)]2 (3), [Cu-(μ-Br)-{μ-N,N′-(PySeSePy)}]n (4), [Cu-(μ-Cl)-N,N′-(PySeSePy)]2 (5), [Zn(OOCC6F5)2-N,N′-(PySeSePy)] (6) and [Zn (OSO2CF3)2-N,N′-(PySeSePy)] (7) have been synthesised and the crystal structures of 1, 3, 4 and 6 determined. 1, 3 and 6 display seven-membered metallacycles with tetrahedral coordination of the metal centres. In these cases 2,2′-dipyridyldiselenide acts as a chelating ligand. In the polymeric complex 4, 2,2′-dipyridyldiselenide acts as a bridging ligand. All com­ plexes display selenium-selenium single bonds with an average length of 232 pm. In contrast to the analogous chloro and nitrato complexes, the zinc complexes 6 and 7 are not dissociated in solution, as evidenced by 77Se NMR experiments. The corresponding resonances are shifted downfield in comparison with the ligand.
Zur Chemie von Mischphasen in komplexen Zustandsdiagrammen Das System Bi2O3/Bi2Se3/Bi2Te3/Chemistry of Mixed Crystals in Complex Phase Diagrams The System Bi2O3/Bi2Se3/Bi2Te3
Authors: Schmidt P. , Oppermann H.
Published: February 2015

Pseudoternary System Bi2O3/Bi2Se3/Bi2Te3, Phase Diagram, Thermodynamic Data The phase diagram of the pseudoternary system Bi2O3/Bi2Se3/Bi2Te3 is found to include a quaternary solid solution Bi2O2 (TexSe1-x) and ternary, intermetallic mixed crystals Bi2(TexSe1-x)3. Using thermodynamic modeling of the solid solutions it is possible to calcu­ late complex heterogeneous equilibria between all phases of this phase diagram. As a result we can thermodynamically describe the observed phase relations:

Bi2(TexSe1-x)3 ⊿H°m(298) = 0; ⊿S°m(298) = R[xlnx + (1-x)ln(1-x)]

Bi2O2(TexSe1-x) ⊿H°m(298) = Ω · x(1-x); O⊿S°m(298) = R/4 [xlnx + (1-x)ln(1-x)]

Ω = 0,6 kcal/mol
Kristallstruktur und spektroskopische Charakterisierung von Hexamethyl- disilazan-Aluminiumtrichlorid [(H3C)3Si]2NH ∙ AlCl3 / Crystal Structure and Spectroscopic Characterisation of Hexamethyl- disilazane-trichloroalum inum [(H3C)3Si]2NH ∙ AlCl3
Authors: Jansen Martin , Jäschke Thomas
Published: February 2015

By reaction of hexamethyldisilazane with aluminium trichloride in hexane hexamethyldisilazane-trichloroaluminum [(H3C)3Si]2NH • AlCl3 is formed. The adduct has been characterized by MS, IR, Raman, 1H, 13C, 27Al, 29Si NMR spectroscopy, and by a crystal structure determination (1425 independent reflections, R = 0.035). The space group is Pbca with a = 1312,6(5), b = 1182,9(5), c = 1964,7(5) pm; Z = 8. [(H3C)3Si]2NH • AlCl3 forms monomeric units which have point symme­try C1 and exhibit an Al − N bond length of 193,9(3) pm.
19β → 28-Lactonization of Pomonic Acid from Lantana camara roots
Authors: Misra Laxminarain , Laatsch Hartmut
Published: February 2015

Lantana camara L. var. aculeata yielded a triterpenoid, pomonic acid (1). The acid-catalyzed lactonization of this γ-hydroxy acid afforded a rearranged lactone 3, the structure of which was as­ signed by detailed 2D-NMR studies. A reaction mechanism involving a 1,3-butadiene intermediate is proposed.
Wechselwirkungen in Molekülkristallen, 157 [1, 2]. Mischkristallzüchtung und Strukturbestimmungen von Tetra(3,4-dimethylphenyl)-imidodiphosphat-Salzen mit Alkalikation- Verhältnissen K⊕/Rb⊕(1:5) und Rb⊕/Cs⊕(1:1) / Interaction in Molecular Crystals, 157 [1, 2]. Mixed Crystal Growth and Structure Determinations of Tetrakis(3,4-dimethylphenyl)-imidodiphosphate Salts with Alkali Cation Ratios K⊕/Rb⊕ (1:5) and Rb⊕/Cs⊕ (1:1)
Authors: Bock Hans , Heigel Erik
Published: February 2015

Mixed crystals of tetrakis(3,4-dimethylphenyl)imidodiphosphate salts with alkalication ratios K⊕/Rb⊕ (1:5) and Rb⊕/Cs⊕ (1:1), (1:3) as well as (3:1) have been grown by suspending finely ground stoichiometric mixtures of alkali carbonates in toluene solutions of the strongly chelating ligand HN(PO(OR)2)2 - The cation ratios were measured by Total Reflexion X-Ray Fluorescence (TXRF) analysis and the single crystal structures of the polymeric K⊕/Rb⊕ as well as the Rb⊕/Cs⊕ imidodiphosphate salts determined by X-ray structure analysis. The selectivity of the various alkali ions for insertion in the crystal lattices of the individual imidodiphosphate salts has been confirmed by concentration-dependent crystallizations and discussed based on the structural analysis of the differing ligand conformations. The unit cell parameter dependence on the alkali cation radii provided information on van der Waals interactions between adjacent phenyl rings of the imidodiphosphate ligands and suggests the selective alkali cation insertion to be partly due to supramolecular repulsion within the lipophilic phenyl skin during the selfaggregation of the polymeric salt chains
Metallkomplexe mit biologisch wichtigen Liganden, CXXVIII [1], Palladium(II)-Komplexe mit deprotonierten Peptidestern als N,N′-Chelatliganden / Metal Complexes with Biologically Important Ligands, CXXVIII [1]. Palladium(II) Complexes with Deprotonated Peptide Esters as N,N′-Chelate Ligands
Authors: Hoffmüller Winfried , Krämer Roland , Maurus Michael , Polbom Kurt , Beck Wolfgang
Published: February 2015

Reactions of chloro bridged palladium compounds with di- and tripeptide esters give (Et3P)(Cl)2Pd(NH2CHR1CONHCHR2CO2CH3) and the N,N′-chelate compounds (Et3P)- (Cl)Pd(NH2CH2CONCHR1 CO2R2), [C6H4CH 2NMe2(C,N)]Pd(NH2CH2CONCH2CO2Et) and (Et3P)Pd(gly-gly-glyOMe-2H+). The structure of (Et3P)(Cl)Pd(gly-alaOMe-H+) was determined by X-ray diffraction analyses. Attempts to form open chain peptides from α-amino acid ester in the coordination sphere of palladium(II) are reported
Polylithiation of Small Molecules. Synthesis and Structure of the Functional Lithium Phosphide [Li(TMEDA)]2[PhPCMe2 C5H4]
Authors: Bildmann Ulrich Jürgen , Müller Gerhard
Published: February 2015

Lithium Phosphides, Cyclopentadienides Treatment of 6,6-dimethylfulvene with LiPHPh in hexane/TMEDA (TMEDA = N,N,N′,N′- tetramethylethylenediamine) affords the monolithiated phosphinomethyl cyclopentadienide [Li(TMEDA)][PhHPCMe2C5H4] (1). Further reaction with LinBu in diethylether/TMEDA leads to the formation of the doubly lithiated phosphidomethyl cyclopentadienide [Li(TMEDA)]2[PhPCMe2C5H4] (2) whose crystal and molecular structure was determined (orthorhombic, space group P212121, a = 9.579(4), b = 12.788(2), c = 24.108(6) Å, Z = 4)