Bis(pyrazol-1-yl)acetates as tripodal heteroscorpionate ligands in iron chemistry: syntheses and structures of iron(II) and iron(III) complexes with bpza, bdmpza, and bdtbpza ligands

The molecular structure of the previously reported species "[Fe(bdtbpza)Cl]" has been revealed by X-ray structure determination to be a ferrous dimer [Fe(bdtbpza)Cl](2) (2c) [bdtbpza = bis(3,5-di-tert-butylpyrazol-1-yl)acetate]. The syntheses of ferrous 2:1 complexes [Fe(bpza)(2)] (3a) and [Fe(bdtbpza)(2)] (3c) as well as ferric 1:1 complexes [NEt(4)][Fe(bpza)Cl(3)] (4a) and [NEt(4)][Fe(bdmpza)Cl(3)] (4b) [bpza = bis(pyrazol-1-yl)acetate, bdmpza = bis(3,5-dimethylpyrazol-1-yl)acetate] are reported. Complexes 3a, previously reported [Fe(bdmpza)(2)] (3b), and 3c are high-spin. No spin crossover to the low-spin state was observed in the temperature range of 5-350 K. 4a and 4b are synthesized in one step and in high yield from [NEt(4)](2)[Cl(3)FeOFeCl(3)]. 4a and 4b are iron(III) high-spin complexes. Crystallographic information: 2c (C(24)H(39)ClFeN(4)O(2).CH(2)Cl(2).CH(3)CN) is triclinic, P1, a = 12.171(16) A, b = 12.851(14) A, c = 13.390(13) A, alpha = 98.61(9) degrees, beta = 113.51(11) degrees, gamma = 108.10(5) degrees, Z = 2; 3a (C(8)H(7)Fe(0.5)N(4)O(2)) is monoclinic, P2(1)/n, a = 7.4784(19) A, b = 7.604(3) A, c = 16.196(4) A, beta = 95.397(9) degrees, Z = 4; 3c (C(24)H(39)Fe(0.5)N(4)O(2)) is monoclinic, P2(1)/n, a = 9.939(6) A, b = 18.161(10) A, c = 13.722(8) A, beta = 97.67(7) degrees, Z = 4; 4b (C(20)H(35)Cl(3)FeN(5)O(2)) is monoclinic, C2/c, a = 30.45(6) A, b = 12.33(2) A, c = 16.17(3) A, beta = 118.47(5) degrees, Z = 8.     

NMR-spectroscopic mapping of an engineered cavity in the I14A mutant of HPr from Staphylococcus carnosus using xenon

The interaction between the histidine-containing phosphocarrier protein HPr and xenon atoms in solution is studied in the present paper. Wild-type HPr as well as the exchange mutant I14A have been studied. Specific binding of xenon into an engineered cavity created via the exchange of amino acid residue I14 by alanine could be shown using 1H-15N heteronuclear single-quantum coherence (HSQC) spectroscopy. Xenon binding results in pronounced changes of the 1H and 15N chemical shifts of amide groups close to the cavity. In addition to this observation which allows the NMR-spectroscopic mapping of such cavities, we have shown that the entire molecule is slightly rearranged as a result of xenon binding. In contrast, wild-type HPr only exhibits minor chemical shift changes due to the nonspecific interactions with the xenon atoms in solution.     

Metabonomic analysis of mouse urine by liquid-chromatography-time of flight mass spectrometry (LC-TOFMS): detection of strain,diurnal and gender differences

The application of HPLC-MS combined with principal components analysis (PCA) to the metabonomic analysis of mouse urine is demonstrated. Urine samples from three strains of mouse were analysed by gradient HPLC-MS combined with positive and negative electrospray time-of-flight mass spectrometry. Analysis of the resulting data using PCA enabled the samples to be discriminated between on the basis of gender, strain and diurnal variation. These preliminary results suggest that HPLC-MS-based approaches may have a useful role in metabonomic analysis that complements existing approaches.     

On the derivation and integration of stochastic reaction equations for electronic processes in semiconductors

Zeitschrift für Physik A Hadrons and nuclei - Stochastic reaction equations for electrons in semiconductors contain differential transition probabilities for radiative and nonradiative...     

Zur Quantentheorie der magnetischen Widerstandsänderung

The transmission coefficient of a light polarized in the plane of incidence through a metal foil is calculated, taking into account the excitation of the longitudinal plasma oscillations in addition to the transversal waves inside the metal.     

The principle of complementary energy in nonlinear plate theory

In this paper, the priciple of complementary energy is given for the von Kármán nonlinear plate theory. Thenecessary conditions are three linear and static equilibrium equations in the interior and static boundary conditions on that part of the boundary surface, where forces are prescribed. The stationary value of the complementary energy functional leads to the stress-displacement relations and the geometric boundary conditions.

---

Zusammenfassung In dieser Arbeit wird das komplementäre Variationsprinzip für die nichtlineare Plattentheorie nach von Kármán untersucht. Als notwendige Bedingungen ergeben sich drei lineare statische Gleichgewichtsbedingungen sowie lineare statische Randbedingungen auf dem Teil des Randes, auf dem die Kräfte vorgegeben sind. Für den stationären Wert des Funktionals erhält man die Schnittgrößen-Verformungsbeziehungen sowie die geometrischen Randbedingungen.

     

The singular elastostatic field due to a crack in rubberlike materials

Within the framework of finite-strain elastostatics an asymptotic analysis is carried out in order to calculate the singular field near the crack tip in a slab under conditions of plane deformation. A class of Ogden-Ball hyperelastic rubberlike materials and general loading conditions ensuring vanishing tractions on the crack faces near the crack tip are considered. It is shown that the singular deformation field near the crack tip can be specified by applying a rigid body rotation with a subsequent parallel translation to a so-called canonical field. The adjective canonical is adopted here to denote the field with symmetrically opening crack faces, just resembling the displacement field of the symmetric mode in linear elastic fracture mechanics. No analogy with the antisymmetric mode is possible, and the crack equilibrium criterion requires only one stress intensity factor to be determined.     

Cardiovascular fluid-structure interaction: A partitioned approach utilizing the p-FEM

In this paper, we propose a technique for simulating the fluid-structure interaction in blood vessels. A partitioned approach is used, which allows for an independent discretization of the fluid domain and the structural domain. We choose the finite volume method to solve the Navier-Stokes equations and the p-version of the finite element method (p-FEM) to solve the equations of geometrically nonlinear structural dynamics. The solution strategy can be seen as a first approach towards a comprehensive study of the hemodynamics in vascular substitutes with the goal of improving their long term functionality. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)