bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Periodic and Stochastic Perturbations on Oscillations and Chaos in a Model of the Peroxidase-Oxidase Reaction
Authors: Olsen Lars F.
Published: February 2015

The effects of periodic and random perturbations on the periodic and chaotic oscillations in a model of the peroxidase-oxidase reaction are investigated. The perturbations were chosen to be comparable in size and frequency to those measured in the experimental system. Small periodic perturbations did not affect the dynamics significantly. Small random perturbations, on the other hand, could totally obscure simple periodic dynamics whereas chaotic dynamics turned out to be relatively robust to such perturbations.
A Spectroscopic Study of Pivalophenone, 2-Pivaloylfuran, 2-Pivaloylthiophen and 2-Pivaloylselenophen, and their Sulphur Analogues
Authors: Andrieu Claude G. , Lumbroso Henri
Published: February 2015

Infrared, ultraviolet, 1H and 13C nuclear magnetic resonance spectra were recorded for the title compounds. The infrared carbonyl-band frequencies and intensities, and the H5 chemical shifts, of planar acetophenone, 2-acetylfuran, 2-acetylthiophen and 2-acetylselenophen indicate the order Phenyl < 2-Furyl < 2-Thienyl < 2-Selenyl for Aryl-carbonyl conjugation. Ultraviolet K-band absorption coefficients and carbon-13 chemical shifts provide an estimate of the twisting angle in the pivaloyl derivatives.
Four Channels in the Fission of 252Cf
Authors: Brosa U. , Grossmann S. , Müller A.
Published: February 2015

Strutinsky-type calculations indicate that the potential energy favors four channels in the nuclear fission of 252Cf. The connection of this finding with experimental results on the distribution of fragment mass, total kinetic energy, neutron multiplicities, and relative abundances is discussed. Similar calculations for 227Ac, 236U, and 258Fm show that the changing preponderance of the four channels seems to describe striking trends in the fission of the actinides, in particular the dip in the total kinetic energy at symmetrical fission of 236U and the enormously high average kinetic energy of the 258Fm fragments.
A Higher Order Approximation for the Electronic Structure of Hydrogen in Metals
Authors: Göbel K. , Wahl F.
Published: February 2015

A functional energy difference method based on first principles is used to calculate the electronic contribution to the storage energy of hydrogen impurities in metals. That electronic problem is treated in a higher order approximation which means considering the coupling between one-electron wavefunctions and three-particle amplitudes. A formalism is presented to eliminate all higher order correlations and to reduce the whole system to a one-particle Schrödinger equation with the help of a suitable G reen’s function. The resulting one-electron eigenvalue problem contains some logarithmic singularities due to the fact that there is no gap between occupied and unoccupied electron states in the band structure of a metal. In an electron gas model a convergent theory is reached by an improvement of the Green’s function leading to a screening of the long-range Coulomb potentials. The result is a complicated non-linear algebraic eigenvalue equation which is solved numerically for the special case of a single hydrogen perturbation in a magnesium crystal. The solution shows the influence of higher order electron correlations on the electronic energy eigenvalue of an interstitial hydrogen centre plot as a function of host lattice distortions.
Interpretation of the Influence of Substituents on the UV Spectra of Benzofurans
Authors: Fabian Walter
Published: February 2015

The electronic excitation energies of twelve isomeric methoxy- and nitrobenzofurans were calculated by means of PPP and CNDO/S-CI method. Based on the results of a configuration analysis a simple molecules-in-molecule-type model is proposed which in a semiquantitative manner completely accounts for the characteristic dependence of the UV spectra of these compounds on the position of the substituent.
Distribution of K , the Number of Kekulé Structures in Benzenoid Hydrocarbons Part IV. Benzenoids with 10 and 11 Hexagons
Authors: Cyvin S. J. , Brunvoll J. , Cyvin B. N.
Published: February 2015

An approximate asymptotic formula is derived for the number of normal benzenoids. For this category and h (number of hexagons) = 10 and 11 all numbers of Kekulfe structures were computer and systematized.
A Microwave Fourier Transform Spectrometer in the Region between 26 and 36 GHz
Authors: Dreizler H. , Andresen U. , Gripp J. , Merke I. , Meyer M. , Stahl W. , Schwarz R. , Vormann K.
Published: February 2015

We present a first set up and tests of a microwave Fourier transform spectrometer above 26 GHz with some features differing from the instruments in the lower frequency bands.
Viscosity, Conductivity and Density of Fused Silver and Copper(I) Chlorides Doped with Group I and II Chlorides in the Mole Fraction Region 0 ≦ xdopant ≦ 0.1
Authors: Greening Giorgio G. W. , Weil Konrad G.
Published: February 2015

The density, the electrolytic conductivity and the viscosity of molten silver chloride doped with NaCl, RbCl, MgCl2, CaCl2, SrCl2 and CdCl2, and of molten copper chloride doped with NaCl, KC1, CsCl, MgCl2, CaCl2 and BaCl2 have been measured in the concentration range 0 ≦ xdopant ≦ 0.1: the temperature range was 740 K ≦ T ≦ 900 K for silver chloride and 710 K ^ T ^ 850 K for copper chloride. The findings show that the molar conductance in such systems is strongly dependent on the ionic radii o f the cations: the viscosity, on the other hand, is mainly governed by their charge. A strong correlation exists between the formal activation energies o f conductance and viscosity, Ea
η/Ea
Λ being constant for all types and concentrations of dopant used in this work.
Kristallstruktur und Schwingungsspektrum des Thallium(I)-Zinn(II)-ortho-Thiophosphates TlSnPS4
Authors: Becker Robert , Brockner Wolfgang , Eisenmann Brigitte
Published: February 2015

TlSnPS4 crystallizes in the orthorhombic system, space group Pna21 (Nr. 33), Z = 4 with the lattice constants a = 1175.8 (5) pm, b = 890.1 (4) pm, c = 663.3 (4) pm. In the structure are sligthly distorted discrete PS3-
4 anions.

The far infrared, infrared and Raman spectrum is assigned on the basis of PS3-
4 -units with C3
v symmetry. According to the DTA data the melting point for TlSnPS4 is 575 ± 5 °C. The title compound is not moisture sensitive and semi-conducting.
Adsorption and Reaction of NO on Ni(100)
Authors: Shen Shikong , Feulner P. , Umbach E. , Wurth W. , Menzel D.
Published: February 2015

The adsorption, desorption and decom position of NO on Ni(100 ) was studied with XPS, UPS, XAES, ΔΦ, temperature programmed thermal desorption (TPD) and LEED in the temperature range 80 to 1300 K. NO adsorbs molecularly on Ni(100 ) at low temperatures; dissociation occurs above 200 K. Up to ≈ 1/4 saturation coverage, only N2 desorbs in a second order peak around 1100 K. At saturation three NO desorption states at 350, 420 and 1200 K and two N2 peaks at 660 and 1020 K are observed for a heating rate β of 5 K/s. Activation energies for desorption are obtained by TPD with variable β. Coadsorption experiments show that the NO -TPD peak at 1200 K is due to recombination of N and O on the surface. The relative areas of some TPD maxima depend strongly on coadsorbed O-, C- and N-impurities. At 100 K, ΔΦ increases up to a maximum of 1.1 eV at 3 /4 saturation coverage and drops to 1.0 eV at saturation. Complex LEED patterns are observed for saturated layers adsorbed below 200 K which change during heating. The nature o f the observed binding and desorption states is discussed.
Band Structures of Intercalation Compounds. The System (NH4)(NH3)3(TiS2)4
Authors: Ramirez Rafael , Böhm Michael C.
Published: February 2015

The electronic band structure of the intercalation system ammonia TiS2 has been investigated by a semiempirical self-consistent-field (SCF) Hartree-Fock (HF) crystal orbital (CO) formalism supplemented by an INDO (intermediate neglect of differential overlap) Hamiltonian. A two-dimensional (2D) model for the title system with stoichiometry (NH4)(NH3)3(TiS2)4 has been selected on the basis of available experimental data. The model is defined via a TiS2 monolayer coupled to the intercalant monolayer. The corresponding band-structure properties are compared with bandstructure calculations of monolayered TiS2 and bulk TiS2 . For TiS2 available experimental data and numerical results of conventional band-structure approaches are reported. The interaction between the guest-molecules and the host lattice has the character of a redox-process; i.e. one electron per formula unit has been transferred from the intercalant to the TiS2 layer. One consequence of this transfer is a semiconductor-to-metal transition upon intercalation; an additional consequence is a remarkable electronic reorganization in the TiS2 host. The surplus of electronic charge is predominantly localized at the S centers. The electronic states at the Fermi-level are of Ti 3d character. Two electronic configurations of the title system have been investigated. The mean-field ground state is of a charge density wave type with respect to the TiS2 sublattice. A “symmetry adapted” (SA) configuration is predicted at higher energy.
Dirac and Maxwell’s Equations Derived from the Density Functions
Authors: Majernik V.
Published: February 2015

We present linear transformations between the components of the electric and magnetic fields, E = F1 (H ) and H = F2 (E ), which leave the expression for the density of electromagnetic field energy unchanged. If the coefficients occurring in these transformations are interpreted as the components of the momentum vector of the photon and use is made of the correspondence principle W →∂t and p→∂x, then these transformations turn out to be Maxwell’s equations. In a similar fashion, when starting from the probability density associated with the Dirac wave function, then one can also arrive, via appropriate transformations between the components of the 4- spinor, at the Dirac equation.
The Electron Mean Free Path for Volume Plasmon Excitation in Polycrystalline Beryllium
Authors: Grzeszczak A.
Published: February 2015

Reflection electron energy loss spectra from polycrystalline beryllium for primary electron energies within 100-1000 eV are measured. The peak intensities increase with the primary energy. From this dependence the electron mean free path for volume plasmon excitation in beryllium is evaluated.
Magnetic Field Mapping and NMR Imaging by Multi-Frequency SENEX
Authors: Braun M. , Jung W. I. , Lutz O. , Oeschey R.
Published: February 2015

Nuclear magnetic resonance imaging (MRI) of selectively excited protons has been used for magnetic field mapping in a 1.5 T whole body imager. The imaging has been performed with a modified two pulse SENEX sequence, adapted to single- or multislice operation. The usual spin-echo image is superimposed by field markers which are created by a periodic non-excitation. Results of the method in the fields of image quality control, influence of the susceptibility of an object, and shim and gradient current field response are presented.
Initial Condition and Cooling Time of Recombining Helium Plasma for Stationary VUV Lasing Action
Authors: Furukane Utaro , Tsuji Yasumasa , Oda Toshiatsu
Published: February 2015

Calculated optimum conditions as to initial electron density and cooling rate of a recombining helium plasma for the production of VUV laser oscillation of the Hell 164 nm line are presented together with an explanation of the population inversion mechanism. For high initial plasma density (~1018 cm-3) rapid cooling (τE ≦10-13 sec) should produce a short pulse laser oscillation. For medium initial density (~ 10-16 cm-3), stationary laser oscillation can be produced by much slower cooling (τE ~ 10-8 sec) but on cooling with τE > 10-7 sec the oscillation can hardly be realized. For lower initial plasma density ( ≦ 1015 cm-3), laser oscillation is not possible because the population inversion obtained is not sufficient.
Notizen: On the Relationship Between the Rates of the Radiative and Radiationless Deactivation of the Lowest Triplet State of Aromatic Compounds
Authors: Zander Maximilian
Published: February 2015

For groups of structurally related aromatic compounds with similar T1 - S0 energy gap linear correlations exist be­ tween the rate constants of the radiative and radiationless T1 → S0 transition. Significant exceptions may indicate further radiationless deactivation processes originating in T1 in addition to T1 → S0 intersystem crossing.
On the Concentration Fluctuations of a Binary Mixture of Hard Spheres
Authors: Gallego L. J. , Somoza J. A. , Blanco M. C.
Published: February 2015

We have computed the concentration fluctuations, Scc(0), in a binary mixture of hard spheres on the basis of the Percus-Yevick compressibility (PYC), Percus-Yevick virial (PYV) and Mansoori- Carnahan-Starling (MCS) equations of state. We have also used the Flory-Huggins (FH) model for an athermal solution as a first approximation to the hard sphere description. At fluid packing fraction values, the PYC and MCS theories give similar Scc (0) results, whereas the differences between these and those derived from the PYV equation are more significant. The FH model appears to give rather bad results, which is consistent with the studies of other authors on the entropy of mixing of a binary mixture of hard spheres. The impossibility of a fluid-fluid phase transition in this kind of system is clearly shown by the behaviour of Scc (0) in any of the theories studied.
X-ray Studies on Layer Stacking and Ordering in a Liquid Crystalline Disubstituted Biphenylcyclohexane
Authors: Klämke W. , Haase W.
Published: February 2015

X-ray measurements on disubstituted biphenylcyclohexanc BCH 52 show a crystalline smectic B phase with an ABCA layer stacking in bulk samples when cooled from the nematic to the smectic phase. No temperature dependence of this stacking can be seen. When cooling freely suspended thin films (below 20 μm) from the nematic to the smectic B phase, the obtained X-ray reflexes indicate an arrangement of the molecules in an orthorhombic F like stacking.
Phase Equilibria and Transport Properties in the Systems AgNO3/RCN/H2O. R = CH3, C2H5, C3H7, C4H,, C6H5, and C6H5CH2
Authors: Das Surjya P. , Wittekopf Burghard , Weil Konrad G.
Published: February 2015

Silver nitrate can form homogeneous liquid phases with some organic nitriles and water, even when there is no miscibility between the pure liquid components. We determined the shapes of the single phase regions in the ternary phase diagram for the following systems: silver nitrate /RCN /H2O with R =CH3, C3H7, C6H5, and C6H5CH2 at room temperature and for R =C6H5 also at 60 °C and O °C. Furthermore we studied kinematic viscosities, electrical conductivities, and densities of mixtures containing silver nitrate, RCN, and water with the mole ratios X /4 /1 (0.2≦ X ≦S 3.4). In these cases also R = C2H5 and C4H9 were studied. The organic nitriles show different dependences of viscosity and conductivity on the silver nitrate content from the aliphatic ones.
A New Model System for the Study of Complex Dynamical Enzyme Reactions. I. A Nonlinear Enzyme Reaction in a Chemical Gradient
Authors: Baier Gerold , Urban Peter , Wegmann Klaus
Published: February 2015

An experimental system for the study of biochemical reaction dynamics is introduced and de­ scribed. A one-enzyme reaction is extended by an artificial feedback loop in an electrochemical device. Cyclic voltammetry is used to show that the reaction rate depends nonlinearly on the amount of cosubstrate offered. For some sets of fixed parameter values a damped oscillatory approach of the steady state was observed. The usefulness of the systems theoretical concepts is discussed.
A Numerical and Experimental Study of Reaction Front Propagation in Condensed Phase Systems
Authors: Puszynski J. , Kumar S. , Dimitriou P. , Hlavacek V.
Published: February 2015

Certain noncatalytic exothermic chemical reactions of the type solid-solid characterized by high values of activation energy and heat of reaction represent an example of strongly nonlinear chemically reacting systems. In these systems different types of propagating waves can be observed such as constant pattern, planar pulsating, and rotating waves. Numerical simulations in two and three spatial dimensions predict, qualitatively, the same behavior as experimentally observed. For geometrically large systems multihead spinning or erratic waves occur, which bifurcate from a planar pulsating front. In nonadiabatic systems the spinning wave is more resistant to extinction than the one-dimensional planar pulsating front.
Spin Echo Self-Diffusion Measurements in Molten Salts
Authors: Herdlicka C. , Richter J. , Zeidler M. D.
Published: February 2015

An NMR probe head for diffusion measurements in molten salts at temperatures up to 673 K is described. The spin echo technique using pulsed magnetic field gradients was employed. Resulting self-diffusion coefficients of Na+ in molten NaNO3 in the temperature range 596-670 K are compa­red with literature data obtained by other methods.
Centrifugal Distortion Analysis and Pressure Broadening Studies for l-Type Doublet Transitions of Cyanoacetylene-15N in the Microwave Range
Authors: Haekel J. , Mäder H.
Published: February 2015

With the help of Fourier transform spectrometers in the range from 8 GHz to 26.5 GHz. l-type doublet transitions of HCCC15N in the first excited state of the degenerate bending vibration ν7, with 36 ≤ J ≤ 65, have been investigated. The l-dependence of the resonance frequencies was analy­sed to yield the doubling constant q(0) together with the correction terms q(1) and q(2) due to first and second order contributions from centrifugal distortion. For the lines in X- and Ku-band (8 GHz to 18 GHz) the self-broadening linewidth parameters Γp were determined from the pressure dependence of coherence decay rates 1/T2 of the observed transient emission signals, following pulsed microwave excitation. For the lines with J = 36 and 41, foreign gas broadening in mixtures of HCCC15N with H,. D, and He has also been studied. The experimental results are compared with theoretical predictions, based on a perturbative treatment of binary collisions.
Dielectric Studies on HgCl2: 2 KCl Crystals
Authors: Sastry S. Sreehari , Rao V. Venkata , Satyanandam G. , Raj T. F. Sundar
Published: February 2015

The dielectric properties of HgCl2 : 2 K Cl crystals have been measured as a function of frequency (102-105 Hz) and temperature (304-415 K), along with the d.c. conductivity, in two mutually perpendicular (X and Y) directions. Along the X direction a simple Debye type relaxation mecha­nism is observed at 304 K. A large dielectric anisotropy has been noticed at all frequencies and temperatures. Phase transitions of ferroelectric and order-disorder type are observed along the X and Y direction, respectively.
Deuterium Quadrupole Coupling Constants of Deuterohalogenoacetylens
Authors: Heineking N. , Andolfatto M. , Kruse C. , Eberstein W. , Dreizler H.
Published: February 2015

Employing the high resolution of microwave Fourier transform spectroscopy, we investigated the lowest rotational transitions of fluoro-, bromo-, and iodoacetylene-d. Along with the rotational, centrifugal distortion, halogen nuclear quadrupole, and halogen spin-rotation coupling constants, we determined the deuterium quadrupole coupling constants of bromo-and iodoacetylene-d. For fluoroacetylene-d, we redetermined the deuterium nuclear quadrupole coupling constants with higher accuracy.
MINDO-Forces Calculations of 1-Substituted Cyclopropyl Cations and Anions
Authors: Khalil Salim M.
Published: February 2015

MINDO-Forces calculations are reported, after complete optimization of geometry, for 1-X-sub- stituted cyclopropyl cations and anions, where X is H, O-, OH, NH2, CH3, NO2, CN, F, CHO. All the substituents are stabilizing. It was found that the π-donating groups interact strongly with the cyclopropyl cations, whereas the π-withdrawing groups interact strongly with cyclopropyl anion depending on the electron demand.
Spinodal Decomposition in a Polystyren/ Cyclohexane Solution of Critical Composition
Authors: Schmitz G. , Klein H. , Woermann D.
Published: February 2015

Results of experiments are reported demonstrating spinoidal decomposition in a critical mixture of polystyrene and cyclohexane. If time and length are properly scaled using data obtained from static and dynamic light scattering exper­ iments, the time evolution of the “spinodal ring” is repre­sented to a good approximation by an empirical equation proposed by Snyder and Meakin which describes spinodal decomposition for various types of systems.
Laboratory Rotational Spectrum of PH (N = 2 ← 1) in the 1 THz Region
Authors: Klisch E. , Klein H. , Winnewisser G. , Herbst E.
Published: February 2015

The N = 2 ← 1 rotational transition of the PH radical in its ground electronic (X3 Σ- ) and vibrational states has been measured with the Cologne terahertz spectrometer in the frequency region between 920 and 1070 GHz. The PH radical was generated by immersing red phosphorus in a dc glow discharge of molecular hydrogen buffered with argon. Transition frequencies of the five J′ - J″ fine structure components together with the associated hyperfine structure patterns were precisely measured and analyzed to derive highly accurate molecular parameters, which are more extensive than those reported in the existing literature. Among the determined parameters are the rotational constant B0 = 252200.8099(63) MHz and the centrifugal distortion constant D0 = 13.2915(33) MHz, as well as two fine structure constants - the spin-rotation constant γ0 and the spin-spin interaction constant λ0 - together with their centrifugal distortion contributions Dγ0 and Dλ0. Furthermore, each of the magnetic hyperfine parameters bF, c, and the nuclear spin-rotation constants CI were obtained for both nuclei. The accuracy of previously obtained molecular constants has been improved by up to one order of magnitude. This new set of molecular parameters allows highly reliable frequency predictions of the rotational spectrum extending into the far infrared region; such transition frequencies may be of interest for interstellar spectroscopy.
On the Ambiguity of Complex Structures Derived from one Set of Rotational Constants
Authors: Dreizler H. , Kassi S.
Published: February 2015

It is shown algebraically that from one set of rotational constants or moments of inertia of a complex formed by an asymmetric top molecule and a rare gas atom, eight generally different structures result which are compatible with the moments of inertia.
MO-Theoretical Studies on a Model Complex for Deoxymyoglobin
Authors: Kollma Christian , Fischer Sighart F. , Böhm Michael C.
Published: February 2015

The origin of the displacement of the Fe atom in deoxymyoglobin with respect to the porphyrin plane in the high-spin state is examined by a qualitative molecular orbital (MO) analysis on the extended Hückel level. We find that attachment of a fifth ligand (imidazole in our model complex) to Fe(II)porphyrin favors the out-of-plane shift due to a strengthening of the bonding interaction between Fe and the nitrogen of the imidazole ligand. This results in a high-spin (5 = 2) ground state with Fe shifted out-of-plane for the five-coordinate complex instead of an intermediate spin ground state (5 = 1) with Fe lying in the plane for four-coordinate Fe(II)porphyrin. The relative energies of the different spin states as a function of the distance between Fe and the porphyrin plane are evaluated using an ROHF (restricted open shell Hartree-Fock) version of an INDO (intermediate neglect of differential overlap) method. We observe a level crossing between high-spin and intermediate spin states whereas the low-spin (5 = 0) state remains always higher in energy.
Direct Measurement of the Hydrogen-Hydrogen Correlations in Hydrogenated Amorphous Ni56 Dy44 by Neutron Diffraction
Authors: Lamparter P. , Nuding Ma. , Steeb S. , Bellissent R.
Published: February 2015

From an isotopic mixture of dysprosium with zero neutron scattering length and an isotopic mixture of nickel with zero neutron scattering length ribbons of the amorphous alloy Ni56 Dy44 were produced by melt-spinning and loaded with 59 at% deuterium. A neutron diffraction experiment yielded directly the deuterium-deuterium partial structure factor SDD and the partial pair correlation function GDD . The incorporation of the D-atoms into the amorphous matrix shows an ordering up to five coordination shells at least. The main peak of GDD is split up into a contribution at 2.36 Å with 5.4 nearest neighbours and a contribution at 2.76 Å with 4 neighbours. The D-atoms are located preferentially in Dy4 -tetrahedra, where the occupation of two neighbouring face-sharing tetrahedra is avoided.
Evidence of a Cationic Substitution Domain in Lithium-Manganese Spinels
Authors: Azzoni C. B. , Mozzati M. C. , Paleari A. , Massarotti V. , Bini M. , Capsoni D.
Published: February 2015

Magnetic susceptibility measurements and electron paramagnetic resonance spectra of samples prepared from the reactive system MnO/Li2CO3 with different starting Li cationic fraction x are analyzed, taking into account the structural and compositional information provided by x-ray diffraction. Parent phases, as Mn2O3 , Mn3O4 and Li2 MnO3 , arise together with the lithium-manganese spinel as a result of Li-deficiency or Li-excess with respect to the x = 0.33 composition pertinent to the stoichiometric LiMn2O4 spinel. The data show that the spinel phase can sustain a partial Li-Mn substitution in the cation sites, according to compositional models described, for x > 0.33, by Li1+y Mn3+
1-3y Mn4+
1+2y O4
(Li-rich spinel) and, for x< 0.33, by Li1-|y| Mn2+
|y| Mn3+
1+|y| Mn4+
1-|y| O4 (Li-poor spinel). Paramagnetic resonance data of the Li-poor spinel phase are analyzed to discuss the possible oxidation state of Mn in the tetrahedral site.
Alkylsubstituierte Cyclopentadienylvanadium(V)-Komplexe: tC4H9N=VCpRCl2 / Alkylated Cyclopentadienylvanadium (V) Complexes: tC4H9N =VCpRC l2
Authors: Preuss Fritz , Perner Jens
Published: February 2015

The synthesis of alkylated η5-cyclopentadienylvanadium(V) complexes tC4H9N=VCpRCl2 (CpR = C5H4R, C5H3R2, C5HMe4, C5Me5) is described. The compounds have been investigated by 51V NMR spectroscopy; the 51V resonances are found downfield of the unsubstituted complex tC4H9N=V(η5-C5H5)Cl2. The deshielding of the 51V nucleus increases with the number of substituents R
Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalyse von (Ph3PNPPh3)[OsF5Cl]·CH2Cl2 und cis-(Ph3PNPPh3)[OsF4Cl2]·CH2Cl2 / Crystal Structures, Vibrational Spectra and Normal Coordinate Analysis of (Ph3PNPPh3) [OsF5Cl]·CH2Cl2 and cis-(Ph3PNPPh3 )[OsF4Cl2]·CH2Cl2
Authors: Lorenzen B. , Preetz W.
Published: February 2015

By careful oxidation of the pure fluorochloroosmates(IV) with BrF3 in dichloromethane the mixed pentavalent complex anions [OsF5Cl]- and cis -[OsF4Cl2]- are formed. X-ray structure determinations on single crystals have been performed of (Ph3PNPPh3)[OsF5Cl]·CH2Cl2 (1) (triclinic, space group P1̄, a = 12.153(5), b = 12.387(5), c = 14.229(5) Å , α = 70.07(1), β = 65.46(1), γ = 72.87(1)°, Z = 2) and cis-(Ph3PNPPh3)[OsF4Cl2]·CH2Cl2 (2) (triclinic, space group P1̄, a = 11.987(2) b = 13.083(2), c = 14.456(2) Å, α = 66.30(1), β = 65.47(1), γ = 71.22(1)°, Z = 2). Based on the molecular parameters of the X-ray determinations the IR and Raman spectra for the anions of 1 and 2 have been assigned by normal coordinate analysis. Due to the mutual trans influences the valence force constants of asymmetrically coordinated octahedral axes F•-Os-Cl′ differ from those of the symmetric F-Os-F axes. The data are for 1: fd(OsF•) = 3.95, fd(OsF) = 4.07, fd(OsCl′) = 2.51 and for 2: fd(OsF•) = 3.45, fd(OsF) = 3.97, fd(OsCl′) = 2.42 mdyn/Å
Singly Charged λ6Si-Silicate Anions with an SiF5C Skeleton: Syntheses and Crystal Structure Analyses of the Ionic Hexacoordinate Silicon Compounds [Me3NH][F5SiCH2NMe2H]·H2O and [Me3NH][F5SiCH2NMe2H]·H2O
Authors: Pülm Melanie , Becht Joachim , Tacke Reinhold
Published: February 2015

The zwitterionic λ5Si-tetrafluorosilicates F4SiCH2NMe2H (1) and F4SiCH2NMe3 (2) behave as Lewis acids and react with [Me3NH]F (molar ratio 1:1) in aqueous solution to yield the ionic λ6Si-pentafluorosilicates [Me3NH][F5SiCH2NMe2H] (3) and [Me3NH][F5SiCH2NMe3] (4), respectively. These hexacoordinate silicon compounds contain singly charged λ6Si-silicate anions ([F5SiCH2NMe2H]- , [F5SiCH2NMe3]- ) with an SiF5C skeleton. Compounds 3 and 4 were isolated as the crystalline hydrates 3·H2O (yield 80%) and 4·H2O (yield 82%) which were structurally characterized by single-crystal X-ray diffraction. The Si-coordination polyhedra in the crystals of 3·H2O and 4·H2O are slightly distorted octahedra
Thermische Zersetzung und Lösungskalorimetrie von Ammoniumneodymiodiden / Thermal Decomposition and Solution Calorimetry of Ammonium Neodymium Iodides
Authors: Hennig C. , Oppermann H.
Published: February 2015

The thermodynamical data of ammonium neodymium iodides (NH4)3NdI6 and (NH4)2NdI5 were derived by the determination of their decomposition equilibria by total pressure measurements. Moreover, solution calorimetry was applied. The enthalpies of formation of these phases were calculated from their heats of solution and from the enthalpies of formation and the heats of solution of N dl3 and NH4I in 4n HI (aq.) at 298 K.

Data by total pressure measurement:

⊿H°B(NH4)3NdI6,f,298) = -306,7 ± 4,9 kcal/mol;

S°((NH4)3NdI6,f,298) = 152,8 ± 5,7 cal/K·mol;

⊿H°B(NH4)2NdI5,f,298) = -260,9 ± 4,2 kcal/mol;

S°((NH4)2NdI3,f,298) = 114,3 ± 4,7 cal/K·mol.

Data by solution calorimetry:

⊿H°B(NdI3,f,298) = -154,3 ± 2,0 kcal/mol;

⊿H°B((NH4)3NdI6,f,298) = -299,6 ± 3,2 kcal/mol;

⊿H°B((NH4)2NdI5,f,298) = -255,2 ± 2,8 kcal/mol.
Catalytic Oxidation of a Trialkyl-Substituted Phenol and Aniline with Biomimetic Schiff Base Complexes
Authors: Knaudt Jutta , Förster Stefan , Bartsch Ulrich , Rieker Anton , Jäger Ernst-G
Published: February 2015

The catalytic oxidation of 2,4.6-tri-tert-butylphenol and 2,4,6-tri-tert-butylaniline with molecular oxygen and tert-butylhydroperoxide was investigated using biomimetic Mn-, Fe- and Co-complexes as catalysts. The catalytic activity and product distribution were determined and compared with those observed in the reactions of the well-known Co(salen) complex
2-Hexanoyl-1-tribromomethyl-1,2,3,4-tetrahydro-β-carboline: Crystal Structure Analysis of a Potent Inhibitor of Complex I of Mitochondrial Respiration
Authors: Bringmann Gerhard , Feineis Doris , Brückner Ralph , Peters Eva-Maria , Peters Karl
Published: February 2015

The molecular structure of the title compound 2-hexanoyl-1-tribromomethyl-1,2,3,4-tetra-hydro-β-carboline (3), a potent inhibitor of complex I of the mammalian mitochondrial respiratory chain, has been studied by single-crystal X-ray diffraction analysis. In the crystal, two heterochiral molecules of 3 (i.e., one R- and one S-configured molecule each) were found to be connected with one other in pairs via two intermolecular hydrogen bonds [O(215) ··· H(212)′ and O(215)′ ··· H(212)] to form an overall achiral ‘dimeric’ subunit
Amino Acid Derivatives in Organic Synthesis, Part 4 [1]: Facile Synthesis of Heterocycles Containing a Glycine Residue
Authors: Chabaka Laila M. , Allam Yehia A. , Nawwar Galal A. M.
Published: February 2015

Pyridines, thiazolopyridines and pyrazolopyrans containing glycinate residue were prepared by reacting N-cyanoacryloglycinate ylidenes with active methylene compounds via a Michael addition - intracyclization synthetic pathway.

Simple routes for the synthesis of heterocycles with an amino acid residue were previously reported [1-3] as the incorportation of these residues improves the pharmacokinetics and toxicity of active compounds [4,5]. However, trials to deesterify these residues for coupling purposes were unsuccessful. So, we tried herein new approaches for synthesizing heterocyles carrying one or two glycine moieties with free carboxylic acid group to facilitate further peptide linkage [6] on one hand and on the other one could be able to form metal chelates, a property having a significant output on the toxicological behaviour [7]
Electrochemical Synthesis of a 6-Coordinate Cadmium(II) Complex with N-Methylisatin N(4)-cyclohexylthiosemicarbazone
Authors: Labisbal Elena , Sousa Antonio , Castiñeiras Alfonso , García-Vázquez Jose A. , Romero Jaime , Bain Gordon A. , West Douglas X.
Published: February 2015

Cadmium metal was oxidized in the presence of N-methylisatin N(4)-cyclohexyl-thiosemicarbazone (HMeIs4Chex) in an acetonitrile solution, which produced a complex of the formula [Cd(MeIs4Chex)2]. The two MeIs4Chex ligands are at an angle close to 90° from each other, and there is hydrogen bonding to two adjacent molecules by the anionic ligands remaining NH groups. The complex crystallizes in the monoclinic space group P21/c with a = 11.820(4), b = 11.491(4), c = 27.834(4) Å, β = 106.82(2)°, V = 3618.7(17) Å3 and Z = 4.
Synthesis, Structure and Properties of Poly > [(N-(2-Hydroxyethyl)- N'-carboxymethyl-1,2-ethylenediamine-N, N'-Diacetato)copper(II) Hydrate], {[Cu(Hhedta)] · H2O }n
Authors: Castiñeiras-Campos Alfonso , de la Cueva-Torregrosa Ignacio S. , González-Pérez Josefa M. , Sicilia-Zafra Aurora G. , Bugella-Altamirano Elena , Niclós-Gutiérrez Juan
Published: February 2015

The stoichiometric reaction of N-(2-hydroxyethyl)-1,2-ethylenediamine-N,N,N′-triacetic acid [H3hedta = (HOCH2CH2)(HO2CCH2)NC2H4N(CH2CO2H)2)] and copper(II) hydroxy-carbonate in water yields crystalline samples of poly-{(N-(2-hydroxyethyl)-N′-carboxymethyl-1,2-ethylenediamine-N,N′-diacetato)copper(II) hydrate}, {[Cu(Hhedta)] · H2O}n (I)-The compound was studied by TG analysis (with FT-IR study of the evolved gases), IR, electronic and ESR spectra, magnetic susceptibility data and single crystal X-ray diffraction methods. It crystallises in the orthorhombic system, space group Fdd2 (a = 21.906(2), b = 36.602(4), c = 6.928(1) Å, Z = 16, and final R1 = 0.029 for 1554 independent reflections). The Cu(II) atom exhibits a very distorted octahedral coordination (type 4+1 + 1). The Hhedta ligand plays a N,N′,O,O′O″-pentadentate chelating role as well as a O,O′-carboxylate bridging one and has a free N-carboxymethyl arm. The bridging carboxylate group of the Hhedta ligand leads to polymeric chains {[Cu(Hhedta)] · H2O}n parallel the c axis. A hydrogen bonding network involves all O-H polar bonds (non-ionised carboxylic and alcoholic hydroxyl groups and water molecules). The structure reveals the preferred formation of a copper(II)-(N-2-hydroxyethyl-amino) or copper(II)-(ethanolamino) versus a copper(II)-(N-carboxymethylamino) chelate ring.
Facile Regioselective Synthesis of 1,2,6,8-Tetraazaspiro[4.4]nona-2,6-dien-9-ones
Authors: Girgis Adel S.
Published: February 2015

1,3-Dipolar cycloaddition reaction of nitrilimines to a variety of 3-aryl-5-arylmethylidene- 3,5-dihydro-2-phenyl-4H-imidazol-4-ones (3) afforded the corresponding 1,3,4,7,8-pentaaryl -1,2,6,8-tetraazaspiro[4.4]-nona-2,6-dien-9-ones (4) and not the regio-isomers 2,3,6,8,9-pentaaryl- 1,3,7,8-tetraazaspiro[4.4]nona-1,6-dien-4-ones (5) in high regioselectivity.
A New Triterpenoidal Saponin from the Bark of Guaiacum officinale L.
Authors: Ahmad Viqar Uddin , Saba Nikhat , Ali Zulfiqar , Zahid Muhammad , Alam Naseer
Published: February 2015

A new triterpenoidal saponin, akebonic acid-3-O-[α-L-rhamnopyranosyl-(1→3)-β-D-glucopyranosyl-( l→3)-α-L-rhamnopyranosyl-(l→2)-β-L-arabinopyranoside], named as guaianin Q (1), was isolated from the n-butanolic extract of the bark of Guaiacum officinale L. The structure of 1 was established with the help of the comparative studies of ID and 2D 1H - 13C NMR methods, FABMS, alkaline and acid hydrolyses. In addition to 1, a number of known saponins were also isolated and reported from the same source.
Asymmetrische Katalyse, 134 [1]. Naproxen-Derivate durch enantioselektive Decarboxylierung / Asymmetrische Katalyse, 134 [1]. Naproxen-Derivate durch enantioselektive Decarboxylierung
Authors: Brunner Henri , Schmidt Peter
Published: February 2015

2-Aryl-substituted propionic acids, such as the important anti-inflammatory agent Naproxen, exist in two enantiomeric forms. The (S)-enantiomer of 2-(6-methoxynaphth-2-yl)propionic acid 1 is about 28 times more effective than the (S)-enantiomer. A new catalytic method to synthesize Naproxen (S)-1 involves the enantioselective decarboxylation of suitably substituted malonic acid derivatives. Thus, 2-(6-methoxynaphth-2-yl)-2-methylmalonic acid 6 and its monoester 7 were stirred in THF with catalytic amounts of chiral bases, which induced decarboxylation. After work-up, optical inductions up to 39.8% ee were found in the resulting products 1 and 9. The optically active bases may be fully recycled by extraction.
Synthesis and Structure of a Palladium(II) Chloride Complex with 2-(2-Methyl-3-phenyl-isoxazolidin-5-yl)-pyridine
Authors: Lysenko Andrey B. , Shishkin Oleg V. , Lampeka Rostislav D.
Published: February 2015

The 1:1 complex of palladium(II) chloride with 2-(2-methyl-3-phenyl-isoxazolidin-5-yl)- pyridine (L) has been prepared and studied by means of elemental analysis, 1H NMR spectroscopy and X-ray diffraction (monoclinic, space group P21/n with parameters: a = 8.141(2), b = 9.750(2),c = 20.691(6)Å ,β = 95.62(3)°,V = 1634.4(7)Å3 ,Z = 4 ;R1= 0.054 and wR2= 0.144 for 3352 unique reflections). A square-planar coordination polyhedron has been established for the palladium atom both in acetone solution and in the solid state. The organic ligand is coordinated toometal in a bidentate manner via nitrogen atoms of the pyridine substituent (Pd-N(2) 2.125(3) Å) and the isoxazolidine heterocycle (Pd-N(l) 2.102(3) Å). The other two coordination positions of palladium are occupied by chlorine atoms (Pd-Cl(l) 2.321(1) and Pd-Cl(2) 2.333(1) Å). The six-membered chelate ring formed by Pd, N(2), C(4), C(1), 0(1) and N (1) possesses a “twist-tub” conformation. The isoxazolidine cycle has an envelope conformation with an equatorial orientation of the methyl group.
Supersilylsilane R*SiX3: Umwandlung in Disilane R*X2Si-SiX2R*, Silylene R*XSi, Cyclosilane (R*XSi)n, Disilene R*XSi=SiXR*, Tetrasupersilyl-tetrahedro-tetrasilan [1] / Supersilylsilanes R*SiX3: Conversion into Disilanes R*X2Si-SiX2R*, Silylenes R*XSi, Cyclosilanes (R*XSi)n, D isilenes R*XSi=SiXR*, Tetrasupersilyl-tetrahedro-tetrasilane [1]
Authors: Wiberg Nils , Niederm Wolfgang
Published: February 2015

Supersilylmonohalosilanes R*R SiHCl (R * = Supersilyl = SitBu3) react with Na in C6H6 at 65 °C or with NaC10H8 in THF at - 78 °C with formation of disupersilyldisilanes R*RHSi- SiHRR * in quantitative (R = H , Me) or moderate yields (R = Ph). In the latter case, R *PhSiH2 is obtained additionally at 65 °C (exclusively with Na in THF at 65 °C). Obviously, the supersilylsilanides NaSiHRR* are generated as interm ediates which react with educts R *RSiHCl with NaCl elimination and formation of R*RHSi-SiHRR* (R = H , Me) or R *RSiH2 and R *R Si (R = Ph). The silylene intermediate R*PhSi inserts into the SiH -bonds of the educt R*PhSiHCl and of the product R *PhSiH2 with formation of the disupersilyldisilanes R*PhSiH -SiClPhR* and R*PhSiH -SiHPhR* which are reduced by Na at 65 °C to R*PhSiH2 (and by NaC10H8 at low tem peratures to give R*PhSiH-SiHPhR*). The addition of NaR * to R*RSiHCl in THF at low temperatures leads with NaCl elimination to R*2RSiH (R = H , Me) or to R*RHSi-SiHRR* (R = Me) besides R*C1, or to R*RHSi-SiClRR* (R = Ph) besides R*H and NaR , whereas the addition of R*PhSiH Cl to NaR* in THF at low temperatures results in the formation of NaSiPhR*2 besides R*H and NaCl. In the latter cases (R = Ph), NaR* react with R*PhSiHCl to release the silylene R*PhSi, the transistory existence of which could be proven by trapping it with Et3SiH (formation of R *Ph(Et3Si)-SiH ). Subsequently, R*PhSi inserts into the SiH bond of R*PhSiH Cl (addition of NaR* to R*PhSiHCl) or into the NaSi bond of NaR * (addition of R*PhSiHCl to NaR *). - Supersilyldihalosilanes R*SiHCl2 are converted by Mg in C6H6 at 65 °C into cyclosilanes (R *SiH)n (n = 3, 4) and R*PhSiBrCl by Na at low temperatures - via the silylene R*PhSi - into the disilene R*PhSi=SiPhR*. which is reduced by excess Na to an anion radical. - Supersilyltrihalosilanes R*SiBr2Cl, R*SiBr3 and R*SiI3 react with Na, NaC10H8 or NaR* in T H F with formation of tetrasupersilyl-terrahedro-tetrasilane (R*Si)4 in quantitative yields, whereas the reactions of R*SiCl3 with LiC10H8 in THF at 45 °C lead to (R*Si)4 only in m oderate yields. Obviously, the tetrahedrane is formed from R*SiHal3 via R*SiHal2Na and R*HalSi=SiHalR* as reaction intermediates. The results lead to the following conclusions: (i) Silylenes play a rôle in dehalogenation of “sterically overloaded" supersilylhalosilanes R*R3-nSiHaln· - (ii) A straight-forward procedure for a high-yield synthesis of (R *Si)4 from easily available educts consists in supersilanidation of SiH2Cl2 with NaR*, bromination of the formed supersilylsilane R*SiH2Cl with Br2 and dehalogenation of the bromination product R*SiBr2Cl with Na.
Crystal Structure and Properties of the Titanium Stannide Ti2Sn3
Authors: Künnen Bernd , Jeitschko Wolfgang , Kotzyba Gunter , Mosel B. D.
Published: February 2015

The recently reported binary stannide Ti2Sn3 is confirmed. Its structure was determined from single-crystal X-ray diffractometer data: Cmca, a = 596.7(4), b = 1995(2), c = 701.3(4) pm , Z = 8, R = 0.027 for 817 structure factors and 30 variable parameters. The crystal structure is compared to that of V2GaSn2, which has the same space group symmetry and atomic positions. The Ga atoms of V2GaSn2 occupy those Sn positions of Ti2Sn3 which have the smaller coordination number. The two different titanium atoms of Ti2Sn3 have 11 neighbors of which 3 and 4, respectively, are titanium atoms. The three different tin atoms have 5 titanium with 8 or 10 additional tin neighbors. They show only a slightly broadened but unresolved 119Sn Mössbauer signal with an isomer shift reflecting the high tin content of this intermetallic compound and a relatively large quadrupole splitting of 2.10 mm·s-1. Ti2Sn3 is a good metallic conductor and a Pauli paramagnet.
Regeneration of Carbonyl Compounds from Oximes under Microwave Irradiation in Solventless System
Authors: Heravia Majid M. , Ajami Dariush , Hekmatshoar Rahim , Beheshtiha Yahya Sh. , Assadollah Karim , Ghassem Mitra
Published: February 2015

A new, mild, efficient and environm entally benign method for the cleavage of oximes has been achieved by a simple reaction f oximes with wet alumina supported chromium (VI) oxide under microwave irradiations in solvent-free condition.
[Co4(ν3-NPEt3)2(HNPEt3)2(O2C-CH3)2- (ν-OSiMe2OSiMe2O)2] - ein vierkerniger Cobalt(II)-Komplex mit Leiterstruktur / [Co4(ν3-NPEt3)2(HNPEt3)2(O2C-CH3)2-(ν-OSiMe2OSiMe2O)2] - a Tetranuclear Cobalt(II) Complex with Ladder Structure
Authors: Ackermann Hartmut , Weller Frank , Dehnicke Kurt
Published: February 2015

The title compound has been prepared from cobalt( II) acetate and Me3SiNPEt3 in boiling toluene in the presence of silicon grease and traces of water as blue single crystals which were characterized by IR spectroscopy and by a crystal structure determination. Space group Pbca, Z = 8, lattice dimensions at -50 °C: a = 1449.3(1), b = 1724.9(1), c = 2356.6(2) pm, R = 0.0548.

[Co4(ν3-NPEt3)2(HNPEt3)2(O2C-CH3)2-(v-OSiMe2OSiMe2O)2] has a centrosymmetric structure. The four cobalt atoms which are coordinated tetrahedrally are v3-bridged via the N atoms of the two (NPEt3
-) groups and v2-bridged by the O atoms of the chelating (OSiMe2OSi-Me2O2-) units. The core atoms are arranged in three four-membered rings which are connected in a stair-like way.
Metallkomplexe mit funktionalisierten Schwefelliganden, XV [1]. Reaktionen von Platin(0)-Komplexen mit 1,2,4-Trithiolanen, 1,2,4,5-Tetrathianen, 1,2,3,5,6-Pentathiepanen sowie Thioketonen. Kristallstrukturanalyse von (Ph3P)2Pt(η2-Ph2C=S) / Metal Complexes of Functionalized Sulfur Containing Ligands, XV [1]. Reactions of Platinum(O) Complexes with 1,2,4-Trithiolanes, 1,2,4,5-Tetrathianes, 1,2,3,5,6-Pentathiepanes as well as Thioketones. X-Ray Structure Analysis of (Ph3P)2Pt(η2-Ph2C=S)
Authors: Weigand Wolfgang , Wünsch Ralf , Robl Christian , Mloston Grzegorz , Nöth Heinrich , Schmidt Manfred
Published: February 2015

3,3,5,5-Tetraphenyl-1,2,4-trithiolane (1) reacts with twofold excess of (Ph3P)2Pt(η2-C2H4) (4) to give a 1:1 mixture of the complexes (Ph3P)2

(6a) and (Ph3P)2Pt(η2-Ph2C=S) (7a). Treatment of 3,3,6,6-tetraphenyl-1,2,4,5-tetrathiane (2) with a fourfold excess of 4 yields [Pt2(PPh3)4(μ-S)2] (8) and the platinum(O) compound 7a. The reaction of the 1,2,3,5,6- pentathiepane 3 with a fourfold excess of 4 affords a 1:1:1 mixture of 8, the platinum(O) complex 7b and the bis-thiolato platinum(II) complex 6b. The thioketone complexes 7a-c were formed in smooth reactions of 4 with the thioketones 5a-c. The molecular structure of (Ph3P)2Pt(η2-Ph2C=S) (7a) has been established by single-crystal X-ray analysis.
Chiral Copper(I) Iodide Based Porous Coordination Frameworks with Asymmetrically Substituted Bridging N-Donor Ligands
Authors: Roßenbeck B. , Sheldrick W. S.
Published: February 2015

The 2-dimensional coordination polymers 2
∞[{(CuI)2(Mepyz)2} · Mepyz] (1a), 2
∞[CuX(Mepyz)] (2a, X = Br; 2b, X = Cl) and 2
∞[(CuX)2(Mepyz)] (3a, X = I;3b, X = Br) may be prepared by reaction of the appropriate copper(I) halide with 2-methylpyrazine (Mepyz) either in acetonitrile solution at 130 °C (2a/2b, 3a/3b) or without solvent at 20 °C (la). Mepyz ligands bridge (CuI)2 rhomboid dimers in the chiral network of la, whose resulting 24-membered rings are large enough to accomodate an Mepyz guest molecule, la rapidly loses these guests to afford a crystalline powder (lb), that can reversibly imbibe benzonitrile molecules into its open channels. In contrast to la, the sheets of 2a/2b contain zigzag infinite CuX chains, those of 3a/3b staircase 1
∞[CuX] double chains as their characteristic substructures. Helical 3
∞[CuI] single chains in the 3-dimensional network of 3
∞[CuI Mepip)4 are bridged by R-2-methylpiperazine (Mepip) ligands in a second example of a chiral coordination polymer.
Die Kondensation von Ylidylchlorphosphanen mit Phosphanen und Bis(diphenylphosphanyl)methan und -amin / The Condensation of Ylidyl Chlorophosphines with Phosphines and Bis(diphenylphosphino)methane and -amine
Authors: Breitsameter Florian , Mayer Peter , Schmidpeter Alfred
Published: February 2015

Ylidyl chlorophosphanes 1 and dichlorophosphanes 2 react with trimethylsilyl phosphanes to yield the ylidyl diphosphanes 3, 4,5, 7 and the 2-ylidyl triphosphanes 8. From the reaction of compounds 1 with lithium diphosphanyl amide and diphosphanyl methanide result the ylidyl diphosphonium ylides 11 and ylidyl diphosphinimines 13. The former rearrange to give the ylidyl triphosphanyl methanes 12. The chloromethyl diphosphinimine 13c enters a cyclization to give the 1,2,3,5-azatriphosphole derivative 14, the structure of which has been solved by X-ray analysis. From the reaction of ylidyl bis(chlorophosphanes) 17 and 20 with the same reagents the 1,2,4,5-tetraphosphinine derivative 18 and the 1,2,3,5,6-azatetraphosphinine derivatives 19 and 21 are obtained.
Hydrogen Bonding of two l-(φ-Ammonioalkyl)-2-acyl-cyclopentadienides in the Solid State
Authors: Müller Andreas , Maas Gerhard
Published: February 2015

The solid-state structures of a l-(φ-ammoniopropyl)-2-(2-thienylcarbonyl)-cyclopentadienide (2) and a l-(φ-ammoniopentyl)-2-(4-methoxybenzoyl)-cyclopentadienide (3) have been determined. Both betaines self-assemble by NH ··· O hydrogen bonds, but the motifs are different. In the ammoniopropyl case, both intramolecular and intermolecular hydrogen bonds of this type exist, the latter bond being responsible for the formation of infinite chains. In the ammoniopentyl case, intermolecular hydrogen bonds build up a two-dimensional network which contains centrosymmetric dimers held together by NH ··· O=C-aryl hydrogen bonds.