Controlled Synthesis of Large Single Crystals of Metal-Organic Framework CPO-27-Ni Prepared by a Modulation Approach: In situ Single-Crystal X-ray Diffraction Studies

The size of single crystals of the metal-organic framework CPO-27-Ni was incrementally increased through a series of modulated syntheses. A novel linker modulated synthesis using 2,5-dihydroxyterephthalic acid and the isomeric ligand 4,6-dihydroxyisophthalic acid yielded large single crystals of CPO-27-Ni (∼70 μm). All materials were shown to have high crystallinity and phase purity through powder X-ray diffraction, electron microscopy methods, thermogravimetry, and compositional analysis. For the first time single-crystal structure analyses were carried out on CPO-27-Ni. High BET surface areas and nitric oxide (NO) release efficiencies were recorded for all materials. Large single crystals of CPO-27-Ni showed a prolonged NO release and proved suitable for in situ single-crystal diffraction experiments to follow the NO adsorption. An efficient activation protocol was developed, leading to a dehydrated structure after just 4 h, which subsequently was NO-loaded, leading to a first NO loaded single-crystal structural model of CPO-27-Ni.     

Evaluation of quadrature schemes for the discrete ordinates method

After reviewing the presently available quadrature schemes for the discrete ordinates method, the accuracy of different schemes is analyzed and evaluated. It is shown from a comprehensive error analysis that the moment conditions have to satisfied not only for the principal coordinates directions, as it is mostly carried out, but for any arbitrary test direction. Among the schemes with approximately 50 discrete ordinates the DCT-020-2468 quadrature was found to give the best accuracy. The highest accuracy among all schemes is achieved by the LC-11 quadrature which requires 96 discrete ordinates. This scheme is rarely used up to date and deserves more attention for high accuracy predictions.     

Nd3Si5AlON10 – Synthese,Kristallstruktur und Eigenschaften eines Sialons im La3Si6N11‐Strukturtyp

Nd₃Si₅AlON₁₀ – Synthesis, Crystal Structure, and Properties of a Sialon Isotypic with La₃Si₆N₁₁ Nd₃Si₅AlON₁₀ was synthesized by the reaction of silicon diimide, aluminium nitride, aluminium oxide, and neodymium in a pure nitrogen atmosphere at 1650 °C using a radiofrequency furnace. The compound was obtained as a coarsely crystalline solid. According to the single‐crystal structure determination the title compound is isotypic with Ln₃Si₆N₁₁ (Ln = La, Ce, Pr, Nd, Sm). Nd₃Si₅AlON₁₀ (P4bm, a = 1007.8(1), c = 486.3(1) pm, Z = 2, R₁ = 0.016, wR₂ = 0.031) is built up by a three‐dimensional network structure of corner sharing SiON₃ and (Si/Al)N₄ tetrahedra (molar ratio Si : Al = 3 : 1). According to lattice energetic calculations using the MAPLE concept a differentiation of O and N seems to be reasonable. One of the two different sites for the tetrahedral centres is probably occupied by Si (distances: Si–O: 168.4(1), Si–N: 173.6(3)–176.0(4) pm) the second site by Si and Al with the molar ratio 3 : 1 (distances: (Si/Al)–N: 172.0(3)–176.6(2) pm). The Nd³⁺ ions are located in the voids of the (Si₅AlON₁₀)^9– framework (distances: Nd–O: 261.07(8), Nd–N: 246.1(2)–286.6(2) pm).     

Consistency of surface mechanical properties of spread protein layers at the liquid–air interface at different spreading conditions

Π/A isotherms of spread β-lactoglobulin and β-casein at the air–water interface are measured under different spreading conditions. While the isotherms do not show drastic effects of the spreading concentration and the compression rate the interfacial shear rheological behaviour is significantly influenced. In particular, the shear viscosity of β-lactoglobulin layers depend directly on the spreading concentration. Significant viscosity increase is obtained at larger surface pressures when the spreading concentration is increased. In contrast the shear rheology of the spread β-casein layers can be normalised by plotting the viscosities as a function of the surface pressure Π. The different behaviour is discussed in terms of denaturation of the β-lactoglobulin during the monolayer formation process by adsorption from the spread thin protein solution layer.     

Wasserstoffbrücken in 1,1‐Bis(2‐hydroxyethyl)‐3‐benzoylthioharnstoff und seinen Nickel(II)‐ und Kupfer(II)‐Chelat‐Komplexen

Hydrogen Bonds in 1,1‐Bis(2‐hydroxyethyl)‐3‐benzoylthiourea and its Nickel(II)‐ and Copper(II)‐Chelate Complexes The ligand 1,1‐bis(2‐hydroxyethyl)‐3‐benzoylthiourea HL, ( 1 ), yields with nickel(II) and copper(II) ions neutral complexes [NiL₂], ( 2 ), and [CuL₂], ( 3 ). By X‐ray structure analysis and IR spectroscopy different intramolecular hydrogen bonds (OH…O) and (OH…N) could be identified in both equally coordinated ligands of the [NiL₂] molecule. For comparison X‐ray and IR data were also estimated for 1 and 3 .     

Formation and dissociation of the chloroethylene anions

Electron attachment spectroscopy is employed to study the formation of negative ions from the chloroethylenes. It is found that the resonances recently observed in the total electron scattering cross section are predominantly associated with the formation of Cl^?. Only in tetrachloroethylene is a long-lived parent negative ion observed.