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A structural study of the complex aminated stereotriads [(tert-butyldimethylsilyl)oxy]-4-ethynyl-4-(1-fluorohexyl)-1,2,3-oxathiazocane-2,2-dione (1) and its reduced analogue [(tert-butyldimethylsilyl)oxy]-4-ethenyl-4-(1-fluorohexyl)-1,2,3-oxathiazocane-2,2-dione (2) revealed a k12-type second-order phase transition in 1 and phase stability of 2 over the temperature range 100-298 K. The observed phase change in 1 has been linked to the partial ordering of the extensive positional disorder of the high temperature phase upon cooling as revealed by single-crystal X-ray diffraction. The ordering breaks the translational symmetry, introduces differences in the molecular volumes of the packed species, and results in a low-temperature crystal structure with Z' = 12. The in situ powder X-ray diffraction studies suggest that the transition occurs between 237 and 180 K upon cooling, but complete amorphization in the range of 244-274 K during heating complicated the assignment of the transition temperature. The observed loss of crystallinity has been linked to the phase transition and implies that the loss of long-range order is due to the crystallites undergoing the transformation independently from one another. [ABSTRACT FROM AUTHOR]

Temperature limitations in nickel‐base superalloys have resulted in the emergence of SiC‐based ceramic matrix composites as a viable replacement for gas turbine components in aviation applications. Higher operating temperatures allow for reduced fuel consumption but present a materials design challenge related to environmental degradation. Rare‐earth disilicates (RE2Si2O7) have been identified as coatings that can function as environmental barriers and minimize hot component degradation. In this work, single‐ and multiple‐component rare‐earth disilicate powders were synthesized via a sol‐gel method with compositions selected to exist in the monoclinic C 2/m phase (β phase). Phase stability in multiple cation compositions was shown to follow a rule of mixtures and the C 2/m phase could be realized for compositions that contained up to 25% dysprosium, which typically only exists in a triclinic, P1¯${\rm{\bar{1}}}$, phase. All compositions exhibited phase stability from room temperature to 1200°C as assessed by X‐ray diffraction. The thermal expansion tensors for each composition were determined from high‐temperature synchrotron X‐ray diffraction and accompanying Rietveld refinements. It was observed that ytterbium‐containing compositions had larger changes in the α31 shear component with increasing temperature that led to a rotation of the principal axes. Principal axes rotation of up to 47° were observed for ytterbium disilicate. The results suggest that microstructure design and crystallographic texture may be essential future avenues of investigation to ensure thermo‐mechanical robustness of rare‐earth disilicate environmental barrier coatings. [ABSTRACT FROM AUTHOR]

In situ synchrotron powder diffraction has been used to probe the pressure-dependent structural properties of the magnetic molecular framework material Co(dca)2 [dca = dicyanamide or N(CN)2−]. An orthorhombic ( Pmnn) to monoclinic ( P21/ n) transformation to a high-pressure phase, namely γ-Co(dca)2, occurs at 1.1 GPa. Structural determination of γ-Co(dca)2 shows that the rutile-like topology of the pristine material is retained at high pressures, with the lower symmetry allowing a progression of volume-reducing structural distortions. γ-Co(dca)2 was stable at the maximum pressure measured of 4.2 GPa. Both phases were soft, with bulk moduli ( B0) for α-Co(dca)2 and γ-Co(dca)2 of 13.15 (18) and 9.0 (6) GPa, respectively. Modest uniaxial negative linear compressibility ( K) of the order of −4 TPa−1 was observed over the entire measured pressure range. [ABSTRACT FROM AUTHOR]

The structural characterization of metal-organic frameworks(MOFs) by powder X-ray diffraction can be challenging. Even more difficultare studies of guest solvent or gas molecules inside the MOF pores. Hence, recently we successfully designed several new approaches forstructural investigations of porous MOFs. These methods use structureenvelopes, which can be easily generated from the structure factorsof a few (1-10) of the most intense low index reflections. However, the most interesting results have been found by using differenceenvelope density (DED) analysis. DED can be produced by taking thedifference between observed and calculated structure envelope densities. The generation and analysis of DED maps are straightforward but allowstudying guest molecules in the pores of MOFs by using routine powderX-ray diffraction data. Examples of DED used for studies of solventmolecule location, porosity activation, and gas loading are presentedherein. We show that DED analysis is an important technique in thestudy of host-guest properties in MOFs by providing position, shape, and approximate occupancy of molecules in the MOF pores. [ABSTRACT FROM AUTHOR]

Cocrystallization of 4-nitrophenol(I) with N-methyl substituted aminopyridines,4-N-methylaminopyridine 1, 2-N-methylaminopyridine 2, and 2-N,N-dimethylaminopyridine 3, resultedin three novel adducts 1·2(I), 2·3(I), and 3·3(I), one of which, 2·3(I), wasfound in three polymorphic forms, A, B,and C. The single crystals were grown by slowevaporation from ethanol. The proton transfer from the phenoxy tothe pyridine moieties was registered in all compounds. The adductscomprise pyridinium cations, 4-nitrophenolate anions, and varyingin number neutral 4-nitrophenol molecules. Though the asymmetric hydrogen-bondednetwork involving the −N+H groups of pyridiniumcations and the −C–O–and −C–OHgroups of 4-nitrophenol moieties is registered in the adducts, thedelicate balance of noncovalent interactions that include CH···Ohydrogen bonds and face-to-face stacking interactions between theextended antiparallel arrays of components controls the centrosymmetricpacking. Although three polymorphs of 2·3(I) share several structural common features, they reveal significantdifferences in the conformation of the pyridinium cation, and thehydrogen-bonding patterns. [ABSTRACT FROM AUTHOR]

The synthesis of polycrystalline, as opposed to single-crystalline, porous materials, such as zeolites and metal-organic frameworks (MOFs), is usually beneficial because the former have shorter synthesis times and higher yields. However, the structural determination of these materials using powder X-ray diffraction (PXRD) data is usually complicated. Recently, several methods for the structural investigation of zeolite polycrystalline materials have been developed, taking advantage of the structural characteristics of zeolites. Nevertheless, these techniques have rarely been applied in the structure determination of a MOF even though, with the electron-density contrast between the metal-containing units and pore regions, the construction of a structure envelope, the surface between high- and low-electron-density regions, should be straightforward for a MOF. Herein an example of such structure solution of MOFs based on PXRD data is presented. To start, a Patterson map was generated from powder diffraction intensities. From this map, structure factor phases for several of the strongest reflections were extracted and a structure envelope (SE) of a MOF was subsequently constructed. This envelope, together with all extracted reflection intensities, was used as input to the SUPERFLIP software and a charge-flipping (CF) structure solution was performed. This structure solution method has been tested on the PXRD data of both activated (solvent removed from the pores; dmin = 0.78 Å) and as-synthesized ( dmin = 1.20 Å) samples of HKUST-1. In both cases, our method has led to structure solutions. In fact, charge-flipping calculations using SE provided correct solutions in minutes (6 min for activated and 3 min for as-synthesized samples), while regular charge flipping or charge flipping with histogram matching calculation provided meaningful solutions only after several hours. To confirm the applicability of structure envelopes to low-symmetry MOFs, the structure of monoclinic PCN-200 has been solved via CF+SE calculations. [ABSTRACT FROM AUTHOR]

Hydrothermal reactions of copper(II) acetate, tetrazolate-5-carboxylate (tzc), and the neutral N-donor spacer ligand 1,3-di(4-pyridyl)propane (dpp) lead in a single reaction vial to the simultaneous formation of three different single-crystalline solvates [Cu(tzc)(dpp)]n·0.5C6H14·0.5H2O (1), [Cu(tzc)(dpp)]n·4.5H2O (2), and [Cu(tzc)(dpp)]n·1.25C6H14 (3). All three structures were characterized by single crystal X-ray diffraction. None of these solvates can be prepared as phase-pure bulk materials, but reaction conditions similar to those used for single crystal synthesis yield a phase-pure polycrystalline bulk material of an additional forth solvate phase [Cu(tzc)(dpp)]n·2H2O (4). Investigations of its thermal properties by in situ temperature-dependent synchrotron-based powder diffraction experiments have shown interesting phase transitions upon heating in a helium stream. Initially, the precursor dihydrate 4 transforms to an anhydrous phase [Cu(tzc)(dpp)]n (6I) via the intermediate monohydrate phase [Cu(tzc)(dpp)]n·H2O (5). Upon further heating, phase 6I transforms to a new anhydrous polymorph 6II, which transforms upon cooling to a further new phase 6III. Thermogravimetric measurements performed in tandem with differential scanning calorimetry as well as infrared spectroscopic investigations are in agreement with these findings. The de/resolvation behavior is accompanied by a dramatic change in their magnetic properties: The dihydrate phase shows antiferromagnetic exchange interactions, whereas ferromagnetic properties are observed for the trimorphic anhydrate system. This magnetic sponge-like behavior can be reversibly cycled upon de/resolvation of the material. [ABSTRACT FROM AUTHOR]

A systematic exploration of the assembly of Mo2(O2C-)4-based metal-organic molecular architectures structurally controlled by the bridging angles of rigid organic linkers has been performed. Twelve bridging dicarboxylate ligands were designed to be of different sizes with bridging angles of 0, 60, 90, and 120° while incorporating a variety of nonbridging functional groups, and these ligands were used as linkers. These dicarboxylate linkers assemble with quadruply bonded Mo-Mo clusters acting as nodes to give 13 molecular architectures, termed metal-organic polygons/polyhedra with metal cluster node arrangements of a linear shape, triangle, octahedron, and cuboctahedron/anti-cuboctahedron. The syntheses of these complexes have been optimized and their structures determined by single-crystal X-ray diffraction. The results have shown that the shape and size of the resulting molecular architecture can be controlled by tuning the bridging angle and size of the linker, respectively. Functionalization of the linker can adjust the solubility of the ensuing molecular assembly but has little or no effect on the geometry of the product. Preliminary gas adsorption, spectroscopic, and electrochemical properties of selected members were also studied. The present work is trying to enrich metal-containing supramolecular chemistry through the inclusion of well-characterized quadruply bonded Mo-Mo units into the structures, which can widen the prospect of additional electronic functionality, thereby leading to novel properties. [ABSTRACT FROM AUTHOR]

Reaction of 1,8-dilithionaphthalene with [AuCl(Et3P)] or [Au2Cl2(μ-dppm)] (dppm = bis(diphenylphosphinomethane)) in Et2O/THF leads to formation of bis(triethylphosphine)-1,8-diaurionaphthalene (1) and dppm-1,8-diaurionaphthalene (2), respectively. The dppm ligand present in complex 2bridges the two gold centers leading to formation of short intramolecular Au–Au distances of av. 2.85 . Complex 2reacts with AgPF6in THF/CH2Cl2to afford a dicationic Au4Ag2complex which has been isolated as the bis(hexafluorophosphate) salt (3). In this cluster, two molecules of 2sandwich two Ag cations resulting in the formation of a Au2AgAu2Ag six-membered ring in which the metal centers are connected by Au–Au (av. 2.84 ) and Au–Ag (av. 2.75 ) metallophilic interactions. This cluster is further stabilized by short Ag–C interactions involving some of the naphthalene carbon atoms. The luminescence spectra of 2and 3have been recorded. Both complexes display relatively broad emission bands centered at 540 nm which result, at least in part, from the heavy atom induced phosphorescence of the naphthalene chromophore. [ABSTRACT FROM AUTHOR]

Our Compton profile measurements of Ti and TiH2 using readily available hard X-ray radiation at 27.5 keV, detected by both a Hitachi Vortex silicon-drift detector and a high-resolution superconducting transition-edge sensor array, are found to be in excellent accord with state-of-the-art density functional theory based calculations. The spherically averaged difference between the Compton profiles of TiH2 and Ti is well described by an inverted parabola, supporting an itinerant behavior of the electron gas screening the protons in the Ti matrix. Our experimental approach, validated by two different detectors, extends the applicability of Compton scattering technique to the readily accessible hard x-ray regime (below 30 keV). Our study suggests possibilities for experiments at low-flux bending magnet synchrotron beamlines and paves the way for the development of tabletop Compton experiments with x-ray tubes. [ABSTRACT FROM AUTHOR]

Purification of C2H4 from an C2H4 /C2H6 mixture is one of the most challenging separation processes, which is achieved mainly through energy‐intensive, cryogenic distillation in industry. Sustainable, non‐distillation methods are highly desired as alternatives. We discovered that the fluorinated bis(pyrazolyl)borate ligand supported copper(I) complex {[(CF3)2Bp]Cu}3 has features very desirable in an olefin–paraffin separation material. It binds ethylene exclusively over ethane generating [(CF3)2Bp]Cu(C2H4). This molecular compound exhibits extremely high and record ideal adsorbed solution theory (IAST) C2H4 /C2H6 gas separation selectivity, affording high purity (>99.5 %) ethylene that can be readily desorbed from separation columns. In‐situ PXRD provides a "live" picture of the reversible conversion between [(CF3)2Bp]Cu(C2H4) and the ethylene‐free sorbent in the solid‐state, driven by the presence or removal of C2H4. Molecular structures of trinuclear {[(CF3)2Bp]Cu}3 and mononuclear [(CF3)2Bp]Cu(C2H4) are also presented. [ABSTRACT FROM AUTHOR]

Purification of C2H4 from an C2H4 /C2H6 mixture is one of the most challenging separation processes, which is achieved mainly through energy‐intensive, cryogenic distillation in industry. Sustainable, non‐distillation methods are highly desired as alternatives. We discovered that the fluorinated bis(pyrazolyl)borate ligand supported copper(I) complex {[(CF3)2Bp]Cu}3 has features very desirable in an olefin–paraffin separation material. It binds ethylene exclusively over ethane generating [(CF3)2Bp]Cu(C2H4). This molecular compound exhibits extremely high and record ideal adsorbed solution theory (IAST) C2H4 /C2H6 gas separation selectivity, affording high purity (>99.5 %) ethylene that can be readily desorbed from separation columns. In‐situ PXRD provides a "live" picture of the reversible conversion between [(CF3)2Bp]Cu(C2H4) and the ethylene‐free sorbent in the solid‐state, driven by the presence or removal of C2H4. Molecular structures of trinuclear {[(CF3)2Bp]Cu}3 and mononuclear [(CF3)2Bp]Cu(C2H4) are also presented. [ABSTRACT FROM AUTHOR]

Purifying alkenes from alkanes requires cryogenic distillation. This consumes energy equivalent to countries of ca. 5 million people. Replacing distillation with adsorption processes would significantly increase energy efficiency. Trade‐offs between kinetics, selectivity, capacity, and heat of adsorption have prevented production of an optimal adsorbent. We report adsorbents that overcome these trade‐offs. [Cu‐Br]3 and [Cu‐H]3 are air‐stable trinuclear complexes that undergo reversible solid‐state inter‐molecular rearrangements to produce dinuclear [Cu‐Br⋅(alkene)]2 and [Cu‐H⋅(alkene)]2. The reversible solid‐state rearrangement, confirmed in situ using powder X‐ray diffraction, allows adsorbent design trade‐offs to be overcome, coupling low heat of adsorption (−10 to −17 kJ mol−1alkene), high alkene:alkane selectivity (47; 29), and uptake capacity (>2.5 molalkene mol−1Cu3). Most remarkably, [Cu‐H]3 displays fast uptake and regenerates capacity within 10 minutes. [ABSTRACT FROM AUTHOR]

Purifying alkenes from alkanes requires cryogenic distillation. This consumes energy equivalent to countries of ca. 5 million people. Replacing distillation with adsorption processes would significantly increase energy efficiency. Trade‐offs between kinetics, selectivity, capacity, and heat of adsorption have prevented production of an optimal adsorbent. We report adsorbents that overcome these trade‐offs. [Cu‐Br]3 and [Cu‐H]3 are air‐stable trinuclear complexes that undergo reversible solid‐state inter‐molecular rearrangements to produce dinuclear [Cu‐Br⋅(alkene)]2 and [Cu‐H⋅(alkene)]2. The reversible solid‐state rearrangement, confirmed in situ using powder X‐ray diffraction, allows adsorbent design trade‐offs to be overcome, coupling low heat of adsorption (−10 to −17 kJ mol−1alkene), high alkene:alkane selectivity (47; 29), and uptake capacity (>2.5 molalkene mol−1Cu3). Most remarkably, [Cu‐H]3 displays fast uptake and regenerates capacity within 10 minutes. [ABSTRACT FROM AUTHOR]

The title diadduct, C16H16O2, has been redetermined by X-ray diffraction methods at 120 K. In this work, we report more exact values of bond and angles. [ABSTRACT FROM AUTHOR]

A bent Bragg-Laue monochromator (BLM) is proposed for high-energy X-ray (∼25-60 keV) beamlines. The BLM has the unique feature of bi-directional focusing. A sagittally bent Laue crystal can focus the large horizontal fan of a bending magnet or wiggler source. A meridionally bent Bragg crystal focuses the beam vertically and corrects for the anticlastic bending effects of the Laue crystal. This monochromator geometry relies on the crystal orientations being optimized. It is shown that the focusing condition and Rowland condition can be simultaneously satisfied at a given energy. Detailed ray tracings indicate that a BLM can provide similar energy resolution and higher flux density compared to a sagittally bent double-Laue monochromator configuration. A prototype BLM with a symmetric Bragg crystal and an asymmetric Laue crystal was tested. Matching of the bend radii of the two crystals in the meridional direction was demonstrated. In general, the horizontal acceptance of the sagittally bent Laue crystal is limited by the large curvature. This horizontal BLM acceptance could be increased by translating the Laue crystal along its sagittal bending axis. [ABSTRACT FROM AUTHOR]

Despite being the fifth most abundant element in the atmosphere, neon has never been observed in an organic or metal–organic environment. This study shows the adsorption of this highly unreactive element within such an environment and reveals the first crystallographic observation of an interaction between neon and a transition metal. [ABSTRACT FROM AUTHOR]

A monoclinic modification of chloridomercurioferrocene, [FeHgCl(C5H4)(C5H5)], was found on its crystallization from acetonitrile. A triclinic form of the title compound [Sunkel & Kiessling (2001). J. Organomet. Chem. 637, 796–799] was crystallized from chloroform. Both forms have two molecules per asymmetric unit. In the monoclinic form, both molecules have an eclipsed conformation, while in the triclinic form one of them has an eclipsed and the other a staggered conformation. In the monoclinic crystals, molecules form infinite ribbons due to intermolecular secondary coordination between Hg and Cl atoms, while in the triclinic form molecules are arranged in tetramers. [ABSTRACT FROM AUTHOR]

The low-temperature study of the title compound, (C36H30NP2)2[Cu2Br4], revealed the nature of rotational disorder which has been observed at room temperature for the [Cu2Br4]2− anion. The centrosymmetric anion has a planar structure with slightly distorted trigonal coordination of the Cu atoms. [ABSTRACT FROM AUTHOR]

An ortho­rhom­bic (space group Pbcn) polymorph of the title compound, C18H22O7S2, was obtained from a methanol solution to complement the known monoclinic (space group C2/ c) phase. No phase transition has been found between the two systems in the temperature range 120–296 K. The central O atom of the mol­ecule has site symmetry 2. [ABSTRACT FROM AUTHOR]

Substantial improvements in cycle life, rate performance, accessible voltage, and reversible capacity are required to realize the promise of Li-ion batteries in full measure. Here, we have examined insertion electrodes of the same composition (V2O5) prepared according to the same electrode specifications and comprising particles with similar dimensions and geometries that differ only in terms of their atomic connectivity and crystal structure, specifically two-dimensional (2D) layered α-V2O5 that crystallizes in an orthorhombic space group and one-dimensional (1D) tunnel-structured ζ-V2O5 crystallized in a monoclinic space group. By using particles of similar dimensions, we have disentangled the role of specific structural motifs and atomistic diffusion pathways in affecting electrochemical performance by mapping the dynamical evolution of lithiation-induced structural modifications using ex situ scanning transmission X-ray microscopy, operando synchrotron X-ray diffraction measurements, and phase-field modeling. We find the operation of sharply divergent mechanisms to accommodate increasing concentrations of Li-ions: a series of distortive phase transformations that result in puckering and expansion of interlayer spacing in layered α-V2O5, as compared with cation reordering along interstitial sites in tunnel-structured ζ-V2O5. By alleviating distortive phase transformations, the ζ-V2O5 cathode shows reduced voltage hysteresis, increased Li-ion diffusivity, alleviation of stress gradients, and improved capacity retention. The findings demonstrate that alternative lithiation mechanisms can be accessed in metastable compounds by dint of their reconfigured atomic connectivity and can unlock substantially improved electrochemical performance not accessible in the thermodynamically stable phase. [ABSTRACT FROM AUTHOR]

Using a ligand bearing a bulky hydrophobic group, a "shish kabob" of nanocages, has been assembled through either a one-fell-swoop or a step-by-step procedure by varying the dielectric constant of the assembly mixture. A hydrophobic solvent breaks down the chain to discrete nanocages, while a hydrophilic solvent reverses the procedure. Although the shish kabob of nanocages has exactly the same chemical composition and even the same Archimedean-solid structure as those of its discrete analogue, its gas-adsorption capacity is remarkably improved because assembly of a chain exposes the internal surface of an individual cage. This dimension-augmentation strategy may have general implications in the preparation of porous materials. [ABSTRACT FROM AUTHOR]

Heterocyclic privileged medicinal scaffolds involving pyridine, 1,4-dihydropyridine, chromeno[2,3-b]pyridine, and dihydro-1,4-dithiepine frameworks are prepared via a single-step multicomponent reaction of structurally diverse aldehydes with various thiols and malononitrile. Mechanistic studies of the synthetic pathway leading to pyridines reveal that 1,4-dihydropyridines undergo oxidation by the intermediate Knoevenagel adducts rather than by air oxygen. The use of o,o′-disubstituted aromatic aldehydes leads to the corresponding 1,4-dihydropyridines, whereas salicylic aldehydes result in chromeno[2,3-b]pyridines. Reactions of ethanedithiol as a thiol component produce dimeric pyridines with sterically unencumbered aldehydes, while o,o′-disubstituted aromatic aldehydes give dihydro-1,4-dithiepines. Thus, depending on the aldehyde and thiol types, diverse libraries of medicinally relevant compounds can be prepared by a simple one-step process involving no chromatography. [ABSTRACT FROM AUTHOR]

Abstract: Benzopyrano[2,3-b]pyridine is an important privileged medicinal scaffold. A three-component reaction of salicylaldehydes, thiols and 2equiv of malononitrile that leads to the formation of a series of compounds incorporating 2,4-diamino-3-cyano-5-sulfanylbenzopyrano[2,3-b]pyridine framework is described. A proposed mechanism with the supporting experimental data is presented. [Copyright &y& Elsevier]

The giant sarcomeric protein titin contains a protein kinasedomain (TK) ideally positioned to sense mechanical load. We identified asignaling complex where TK interacts with the zinc-finger protein nbr1through a mechanically inducible conformation. Nbr1 targets theubiquitin-associated p62/SQSTM1 to sarcomeres, and p62 in turn interactswith MuRF2, a muscle-specific RING-B-box E3 ligase and ligand of thetransactivation domain of the serum response transcription factor (SRF).Nuclear translocation of MuRF2 was induced by mechanical inactivity andcaused reduction of nuclear SRF and repression of transcription. A humanmutation in the titin protein kinase domain causes hereditary muscledisease by disrupting this pathway. [ABSTRACT FROM AUTHOR]

Titelbild: Overcoming Fundamental Limitations in Adsorbent Design: Alkene Adsorption by Non-porous Copper(I) Complexes (Angew. Keywords: adsorption; alkenes; copper; olefin separation; X-ray diffraction EN adsorption alkenes copper olefin separation X-ray diffraction 20897 20897 1 11/11/20 20201116 NES 201116 B Das Eisberg-Motiv b illustriert, wie H. V. R. Dias, M. G. Cowan et al. in ihrem Forschungsartikel auf S. 21187 Lösungschemie in einer Festkörperreaktion für die Trennung von Alkenen und Alkanen nutzen. Adsorption, alkenes, copper, olefin separation, X-ray diffraction. [Extracted from the article]

Benzene and acetonitrile are two of the most commonly used solvents found in almost every chemical laboratory. Titan is one other place in the solar system that has large amounts of these compounds. On Titan, organic molecules are produced in the atmosphere and carried to the surface where they can mineralize. Here, we report the phase diagram of mixtures of acetonitrile and benzene, and provide an account of the structure and composition of the phases. To mimic the environment on Titan more accurately, we tested the stability of the structure under liquid ethane. The results provide new insights into the structure and stability of potential extraterrestrial minerals. In light of Dragonfly, NASA's upcoming mission to Titan, revisiting the fundamental chemistry of the smallest molecules with modern methods and techniques can have significant contributions to this epochal mission and can open new research directions in chemistry. [ABSTRACT FROM AUTHOR]

Fuel injection causes considerable oscillations of fuel pressure at the injector inlet. One of the reasons is hydraulic impact when the needle valve closes. For multiple injections, the previous injections affect the following. As both the fuel pressure in rail pac and the injection rate grow, the oscillations increase. The pressure oscillation range at the common rail injector inlet at pac=1500 bar is up to 350 bar, and at the rail pressure pac=500 bar, the amplitude decreases to 80 bar. Physical properties of the fuel are also important. As the viscosity of the fuel increases, its hydraulic friction grows which results in a rapid damping of pressure oscillations. The data for an injector operating on sunflower oil is presented. As compared with diesel fuel, the oscillations range decreases from 400 to 250 bar at the same operating mode. The influence of the interval between the impulses of a double injection on the injection rate of the second fuel portion was investigated. Superposition of two waves during multiple injections may result in amplification and damping of the oscillations. Simulation was performed to estimate the influence of fuel type and time interval 't between control impulses of a double injection on the injection quantity of the second portion at pressures of 2000-3000 bar. When the rail pressure pac grows, the oscillations and their impact on the injection process increase. For diesel fuel at pressure of pac=2000 bar, the variation in injection rates of the second portion is 2.36-4.62 mg, and at pac=3000 bar - 1.58-6.63 mg. [ABSTRACT FROM AUTHOR]

A super-paddlewheel (comprised of two paddlewheels) metal–organic polyhedron (MOP) containing surface hydroxyl groups was synthesized and characterized. Condensation reactions with linear alkyl anhydrides lead to new MOPs with enhanced solubility. As a result, the surface-modified MOP 4 was demonstrated as a homogeneous Lewis-acid catalyst. [ABSTRACT FROM AUTHOR]

A NbO-type metal–organic framework, PCN-46, was constructed based on a polyyne-coupled di-isophthalate linker formed in situ. Its lasting porosity was confirmed by N2adsorption isotherm, and its H2, CH4and CO2adsorption capacity was examined at 77 K and 298 K over a wide pressure range (0–110 bar). [ABSTRACT FROM AUTHOR]

Calibration of area detectors from powder diffraction standards is widely used at synchrotron beamlines. From a single diffraction image, it is not possible to determine both the sample‐to‐detector distance and the wavelength, but, with images taken from multiple positions along the beam direction and where the relative displacement is known, the sample‐to‐detector distance and wavelength can both be determined with good precision. An example calibration using the GSAS‐II software package is presented. [ABSTRACT FROM AUTHOR]

Introduction: The objective of the study was to evaluate the prevalence of Clostridium difficile-associated diarrhoea (CDAD) among hospitalised patients with antibiotic-associated diarrhoea (AAD) in general and by specific types of medical care and hospital units.Methods: A prospective, cross-sectional, non-interventional, multicentre study. The main inclusion criteria were: patient age ≥ 18 years, hospital stay of at least 48 h, current antibiotic therapy or antibiotic therapy within the previous 30 days, loose stools (Bristol stool types 5-7 and stool frequency ≥ 3 within ≤ 24 consecutive hours or exceeding normal for the patient) and signed informed consent form. The stool sample was taken to the local (study site) microbiology laboratory for detection of glutamate dehydrogenase (GDH) and toxins A/B using enzyme immunoassay (EIA) stool test.Results: From April 2016 to April 2017, a total of 1245 patients from 12 large hospitals were enrolled in the study. Data on 81 patients were excluded from the analysis for different reasons. Data on 1164 patients (45.2% males and 54.8% females) with a mean age of 54.9 years (range 18-95 years) were analysed. Length of hospitalisation was 2-188 days (median, 8 days). The EIA stool test showed CDAD-positive results in 21.7% (253/1164) patients. The patients were from surgery units (546/1164), internal medicine units (510/1164) and intensive care units (108/1164). The prevalence of CDAD among patients from surgery, internal medicine and intensive care units was 26.2, 17.8 and 17.6%, respectively. Oncology, gastroenterology, septic surgery, oncohaematology and general medical hospital units accounted for more than 75% of all patients included; the prevalence of CDAD by those hospital units was 11.3, 15.0, 39.2, 17.6, and 27.2%, respectively. The proportion of GDH-positive and toxin A/B-negative patients by the rapid stool test result was 16.8% (196/1164). The prevalence of CDAD varied widely between the hospitals (from 0 to 44.3%).Conclusions: The prevalence of CDAD among hospitalised patients with AAD in this study was 21.7% (95% confidence interval: 14.8 and 28.7%). The percentage of CDAD varied widely between hospitals and by specific types of medical care and hospital units. [ABSTRACT FROM AUTHOR]

Sensitized upconversion is explored in three metal–organic frameworks (MOFs) constructed from the anthracene dicarboxylate (ADC) derivatives and zirconium nodes, 9,10-ADC (9,10-MOF), 2,6-ADC (2,6-MOF) and 1,4-ADC (1,4-MOF). Selective excitation of surface-bound Pd(ii) mesoporphyrin IX (PdMP) gives rise to delayed fluorescence (τ = 370 ± 30 ns) from anthracene in the 9,10-MOF. The overall upconversion efficiency of the Pd@9,10-MOF is 0.46 ± 0.05% with a threshold intensity of 104 ± 26 mW cm−2. [ABSTRACT FROM AUTHOR]

Heat treatment of cubic YbZrF7, after quenching from 1000 °C, leads to a material displaying precisely zero thermal expansion at ~300 K and negative thermal expansion at lower temperatures. The zero thermal expansion is associated with a minimum in the lattice constant at ~300 K. X-ray total scattering measurements are consistent with a previously proposed model in which the incorporation of interstitial fluoride into the ReO3-related structure leads to both edge and corner sharing coordination polyhedra. The temperature dependence of the experimental pair correlation functions suggests that the expansions of edge and corner sharing links partly compensate for one another, supporting the hypothesis that the deliberate incorporation of excess fluoride into ReO3 structure materials can be used as a design strategy for controlling thermal expansion. Cubic YbZrF7 has a bulk modulus, K0, of 55.4(7) GPa and displays pronounced pressure-induced softening [K0' = -27.7(6)] prior to an abrupt amorphization on compression above 0.95 GPa. The resulting glass shows a single sharp scattering maximum at Q ~ 1.6 Å-1. [ABSTRACT FROM AUTHOR]

The structural phase transition accompanied by a Jahn-Teller switch has been studied over a range of H/D ratios in (NH4)2[Cu(H2O)6](SO4)2 (ACTS). In particular, single-crystal neutron diffraction investigations of crystals with deuteration in the range 50 to 82% are shown to be consistent with previous electron paramagnetic resonance (EPR) experiments exhibiting a phase boundary at 50% deuteration under ambient pressure. Polycrystalline samples show that the two phases can co-exist. In addition, single-crystal neutron and polycrystalline X-ray diffraction pressure experiments show a shift to lower pressure at 60% deuteration versus previous measurements at 100% deuteration. [ABSTRACT FROM AUTHOR]

The application of atomic layer deposition (ALD) to metal-organic frameworks (MOFs) offers a promising new approach to synthesize designer functional materials with atomic precision. While ALD on flat substrates is well established, the complexity of the pore architecture and surface chemistry in MOFs present new challenges. Through in situ synchrotron X-ray powder diffraction, we visualize how the deposited atoms are localized and redistribute within the MOF during ALD. We demonstrate that the ALD is regioselective, with preferential deposition of oxy-Zn(II) species within the small pores of NU-1000. Complementary density functional calculations indicate that this startling regioselectivity is driven by dispersion interactions associated with the preferential adsorption sites for the organometallic precursors prior to reaction. [ABSTRACT FROM AUTHOR]

Interleukin-11 (IL-11) and S100P are oncoproteins co-expressed in numerous cancers, which might favor their interaction during oncogenesis. We have explored the possibility of this interaction by surface plasmon resonance spectroscopy, intrinsic fluorescence, and chemical crosslinking. Recombinant forms of IL-11 and S100P interact with each other under physiological level of calcium ions. IL-11 molecule has at least two S100P-binding sites with dissociation constants of 32 nM and 288 nM, which is 5–13-fold lower than its affinity to extracellular domain of IL-11 receptor subunit α. S100P does not alter IL-11-induced STAT3 activation in HEK293 cells co-expressing IL-11 receptors, but could affect other tumorigenic signaling pathways. The highly specific IL-11 – S100P interaction occurring under physiologically relevant conditions should be taken into consideration upon development of the antineoplastics inhibiting IL-11 signaling. [ABSTRACT FROM AUTHOR]

In Moscow Automobile and Road Construction University, investigations are carried out in the field of Diesel engine working process perfection for complying with prospective ecological standards such as Euro-6 and Tier-4. The article describes the results of the first stage of experimental research of the influence of injection pressure up to 3000 bar on working processes of Diesel engine and its fuel system. Justification of the design of a common rail injector for fuel injection under 3000 bar pressure is presented. The influence of raising injection pressure (up to 3000 bar) on the fuel spray propagation dynamics is demonstrated. The combined influence of injection pressure (up to 3000 bar) and air boost pressure on fuel spray propagation dynamics is shown, including on engine emission and noise. [ABSTRACT FROM AUTHOR]

The prototypical single-molecule magnet (SMM) molecule [Mn12O12(O2CCH3)16(OH2)4] was incorporated under mild conditions into a highly porous metal-organic framework (MOF) matrix as a proof of principle for controlled nanostructuring of SMMs. Four independent experiments revealed that the SMM clusters were successfully loaded in the MOF pores, namely synchrotron-based powder diffraction, physisorption analysis, and in-depth magnetic and thermal analyses. The results provide incontrovertible evidence that the magnetic composite, SMM@MOF, combines key SMM properties with the functional properties of MOFs. Most importantly, the incorporated SMMs exhibit a significantly enhanced thermal stability with SMM loading advantageously occurring at the periphery of the bulk MOF crystals with only a single SMM molecule isolated in the transverse direction of the pores. [ABSTRACT FROM AUTHOR]

Through topological rationalization, a zeotype mesoporous Zr-containing metal-organic framework (MOF), namely PCN-777, has been designed and synthesized. PCN-777 exhibits the largest cage size of 3.8 nm and the highest pore volume of 2.8 cm3 g−1 among reported Zr-MOFs. Moreover, PCN-777 shows excellent stability in aqueous environments, which makes it an ideal candidate as a support to incorporate different functional moieties. Through facile internal surface modification, the interaction between PCN-777 and different guests can be varied to realize efficient immobilization. [ABSTRACT FROM AUTHOR]

Through topological rationalization, a zeotype mesoporous Zr-containing metal-organic framework (MOF), namely PCN-777, has been designed and synthesized. PCN-777 exhibits the largest cage size of 3.8 nm and the highest pore volume of 2.8 cm3 g−1 among reported Zr-MOFs. Moreover, PCN-777 shows excellent stability in aqueous environments, which makes it an ideal candidate as a support to incorporate different functional moieties. Through facile internal surface modification, the interaction between PCN-777 and different guests can be varied to realize efficient immobilization. [ABSTRACT FROM AUTHOR]

We demonstrate that rigidifying the structure of fluorescent linkers by structurally constraining them in metal-organic frameworks (MOFs) to control their conformation effectively tunes the fluorescence energy and enhances the quantum yield. Thus, a new tetraphenylethylene-based zirconium MOF exhibits a deep-blue fluorescent emission at 470 nm with a unity quantum yield (99.9 ± 0.5%) under Ar, representing ca. 3600 cm-1 blue shift and doubled radiative decay efficiency vs the linker precursor. An anomalous increase in the fluorescence lifetime and relative intensity takes place upon heating the solid MOF from cryogenic to ambient temperatures. The origin of these unusual photoluminescence properties is attributed to twisted linker conformation, intramolecular hindrance, and framework rigidity. [ABSTRACT FROM AUTHOR]

A 3D Magnesium MOF PCN-72 has been synthesized from the solvothermal reaction of Mg(NO3)2 and a linear ligand. This MOF has a unique structure with 1-dimensional (1D) channel as well as infinite metal chains, which resembles the topology of MIL-53. It is thermally and moisture stable. In situ powder X-ray diffraction studies reveal its interesting phase transitions under temperature change. Calculation shows that each phase of PCN-72 exhibits unique and unusual thermal expansion properties. After removing coordinated solvent at Mg chains, PCN-72 can selectively adsorb CO2 over N2. [ABSTRACT FROM AUTHOR]

A metal-organic framework (MOF) for reversible alteration of guest molecule adsorption, here carbon dioxide, upon photochemical or thermal treatment has been discovered. An azobenzene functional group, which can switch its conformation upon light irradiation or heat treatment, has been introduced to the organic linker of a MOF. The resulting MOF adsorbs different amount of CO2 after UV or heat treatment. This remarkable stimuli-responsive adsorption effect has been demonstrated through experiments. [ABSTRACT FROM AUTHOR]

Abstract: The diarylamido-based PNP pincer ligand can be used successfully for support of organometallic Hf complexes (PNP = [(4-Me-2- i Pr2P–C6H3)2N]). (PNP)HfCl3 (3) was prepared via reaction of (PNP)Li (2) with HfCl4(OEt2). Reactions of (PNP)HfCl3 with alkyl Grignards led to triple alkylation to produce (PNP)HfMe3 (4) with a small methyl or only double alkylation to give (PNP)Hf(CH2SiMe3)2Cl (5) with a larger alkyl. Structures of 3, 4, and 5 in the solid state were established by X-ray diffraction studies. Structures of the alkyl complexes 4 and 5 display remarkably irregular coordination environments about Hf, while in 3 it is approximately octahedral. Compound 4 was found to be thermally stable at 75 °C. On the other hand, thermolysis of 5 at similar conditions led to a mixture of products, the major one of which is believed to be a Hf alkylidene on the basis of in situ NMR spectroscopic observations (e.g., δ 248.2 ppm in the 13C{1H} NMR spectrum). [Copyright &y& Elsevier]

Abstract: Radial (tetracyclopentadienyl)cyclobutadiene pentametals have been synthesized by the Pd-catalyzed coupling of cyclopentadienyltin or of (CpM)zinc reagents with (tetraiodocyclobutadiene)iron(tricabonyl). X-ray structural and NMR data reveal that, while these arrays are crowded, the substituents enjoy considerable rotational freedom. The method constitutes a significant complement to currently existing strategies for the construction of persubstituted cyclobutadiene complexes. [Copyright &y& Elsevier]