An unprecedented 2D isopolymolybdate with (3·4)(3·5·8)(3·4·5·6·8)(3·4·5·6) topology

A novel two-dimensional molybdenum oxide polymer, [Mo₄O₁₃]_n · 2nH₃O, has been prepared under specific hydrothermal conditions and characterized by IR spectroscopy and TG analysis. Single-crystal X-ray diffraction analysis reveals that compound 1 exhibits a (3, 4, 5, 6)-connected 2D layer structure with (3²·4)(3²·5³·8)(3·4²·5⁴·6·8²)(3⁴·4³·5⁴·6⁴) topology, which is constructed by two parallel molybdenum oxide dimeric chains (Mo₂O₁₀)_n bound together by the dimer of Mo₂O₉ subunits via the sharing of corners. Additionally, the electrochemistry activity of compound 1 is also reported.     

High‐pressure synthesis of a 12CaO·7Al2O3–12SrO·7Al2O3 solid solution

Solid solutions of 12CaO·7Al₂O₃ (C12A7) and 12SrO·7Al₂O₃ (S12A7) crystals were synthesized under high pressure. X‐ray diffraction patterns revealed that the lattice constants of the synthesized samples depend linearly on the compositional ratio of C12A7 and S12A7. Electron‐probe X‐ray microanalyses show that the chemical compositions of the crystals are represented by xC12A7·(1?x)S12A7 (0<x<1). These results indicate that the variation in the lattice constants is originated from a difference in the ionic radii of Ca²⁺ and Sr²⁺ ions. From impedance measurements, it was found that S12A7 has the highest conductivity (~1 × 10^?3 Scm^?1 at 550°C) among the solid solutions in the C12A7–S12A7 system.     

Direct Preparation of 7‐Allyl‐ and 7‐Arylindolines

Addition of allyl halides to the organolithium species derived from lithiation of N‐tert‐butoxycarbonylindoline with sec‐butyllithium (sec‐BuLi) and tetramethylethylenediamine (TMEDA) occurs regioselectively by S_N2 allylation. In contrast, the organolithium species can be transmetalated to the mixed zinc cuprate that undergoes regioselective S_N2′ allylations. Transmetalation to the organozinc chloride allows a Negishi‐type cross‐coupling reaction with aryl bromides using palladium catalysis with triphenylphosphine (PPh₃) as ligand. The chemistry was applied to a very short synthesis of 7‐prenylindole and of the alkaloid vasconine.     

A new compound containing five components: 17.2CaO·O.8K2O·6SiO2·3SO3·CaF2

On examining the X-ray diffraction patterns of coatings from the calcining zone of different cement kilns, some lines not attributable to any of the known compounds were found. Through successive attempts it was possible to synthesize a compound having formula 17.2CaO·O.8K₂O· .6SiO₂·3SO₃·CaF₂ whose main lines corresponded to the unknown ones found in the coatings.     

Evidence of the CH···O HydrogenBonding in Imidazolium-Based Ionic Liquids from Far-Infrared Spectroscopy Measurements and DFT Calculations

Knowledge of all the intermolecular forces occurring in ionic liquids (ILs) is essential to master their properties. Aiming at investigating the weaker hydrogen bonding in aprotic liquids, the present work combined computational study and far-infrared spectroscopy on four imidazolium-based ILs with different anions. The DFT calculations of the ionic couples, using the ωB97X-D functional and considering both the empirical dispersion corrections and the presence of a polar solvent, show that, for all samples, the lowest energy configurations of the ion pair present H atoms, directly bound to C atoms of the cation and close to O atoms of the anion, capable of creating moderate to weak hydrogen bonding with anions. For the liquids containing anions of higher bonding ability, the absorption curves generated from the calculated vibrational frequencies and intensities show absorption bands between 100 and 125 cm⁻¹ corresponding to the stretching of the hydrogen bond. These indications are in complete agreement with the presently reported temperature dependence of the far-infrared spectrum, where the stretching modes of the hydrogen bonding are detected only for samples presenting a moderate interaction and become particularly prominent at low temperatures. Moreover, from the analysis of the infrared spectra, the occurrence of various phase transitions as a function of temperature was detected, and the difference in the average energy between the H-bonded and the dispersion-governed molecular configurations was evaluated.     

Barium aluminate hydrates: Part V. 2BaO·Al2O3·2H2O and 2BaO·Al2O3

A new compound of formula 2BaO·Al₂O₃·2H₂O has been synthesised and studied by infra-red, X-ray and thermal analytical techniques. This hydrate yielded another crystalline product, 2BaO·Al₂O₃, during dehydration.     

Multiple anion···π interactions with a soft selenium atom: Accommodation of NCSe anions inside hydrophobic pockets of adamantane/1,2,4-triazole coordination framework

A new framework coordination polymer {[Cd₃(tr₂ad)₆](NCSe)₆·12H₂O}_n [tr₂ad-4,4′-(adamantane-1,3-diyl)bis(1,2,4-triazole)] exhibits 3D primitive cubic topology adopted by trinuclear [Cd₃(tr)₁₂] net nodes and tridentate tr₂ad links. The structure reveals unprecedented multiple anion ···π interactions employing the soft Se site of the ambifunctional NCSe^? anion and three triazole groups pre-arranged on a tricadmium matrix. The framework generates hydrophobic pockets serving for hosting the uncoordinated anions by a concerted action of Se···π and CH···Se interactions.     

Polymerase Synthesis and Restriction Enzyme Cleavage of DNA Containing 7‐Substituted 7‐Deazaguanine Nucleobases

Previous studies of polymerase synthesis of base‐modified DNAs and their cleavage by restriction enzymes have mostly related only to 5‐substituted pyrimidine and 7‐substituted 7‐deazaadenine nucleotides. Here we report the synthesis of a series of 7‐substituted 7‐deazaguanine 2′‐deoxyribonucleoside 5′‐O‐triphosphates (dG^RTPs), their use as substrates for polymerase synthesis of modified DNA and the influence of the modification on their cleavage by type II restriction endonucleases (REs). The dG^RTPs were generally good substrates for polymerases but the PCR products could not be visualised on agarose gels by intercalator staining, due to fluorescence quenching. The presence of 7‐substituted 7‐deazaguanine residues in recognition sequences of REs in most cases completely blocked the cleavage.     

The hydration of 11CaO · 7Al2O3 · CaF2 AT 20°C

Hydration at 20°C of C₁₁A₇ · CaF₂ which exists in regulated set cement was investigated by means of conduction calorimetry, differential thermal analysis, scanning electromicroscopic observation, X-ray diffraction and chemical analysis. The process of hydration and rate of hydration were determined and influence of the various calcium sulfates, calcium hydroxide and carboxylic acid upon the hydration of C₁₁A₇ · CaF₂ was discussed. Mechanism of the strength development was also deduced in relation to the structure of hardened paste.     

Eine η-c-M-beziehung für polymerlösungen

A simple equation is developed for the dependence of the viscosity upon molecular weight and concentration of polymer solutions. The validity of such a simple equation is given if the plot of log η_sp = f (log (c · [η])) is a straight curve for all viscosity values. This is demonstrated for aqueous polyacrylamide solutions. The covered region is M = 12300-6900 000 (g/mol) and concentrations c = 0,1?5 (g/100cm³). The established η-M-c-relationship is:      

A Low‐Sensitivity Composition Based on FOX‐7

1,1‐Diamino‐2,2‐dinitroethene (DADNE, FOX‐7) is considered to be an explosive combining comparatively high performance and low sensitivity. In the present study, FOX‐7 has been evaluated as a possible replacement of RDX in TNT‐based melt‐cast compositions. A composition containing FOX‐7, TNT, Al and wax, and a method of preparing it were proposed. Its sensitivity to impact, friction, shock wave, jet impact, fast heating, and its thermal stability were tested. Some detonation parameters like the detonation pressure, velocity and heat were measured. Moreover, the Gurney velocity, the so‐called effective exponent of the expansion isentrope and the JWL equation of state of the detonation products were determined from the results of a cylinder test. The detonation characteristics were compared with that obtained for cast TNT.     

Pantoea Bacteriophage vB_PagS_MED16—A Siphovirus Containing a 2′-Deoxy-7-amido-7-deazaguanosine-Modified DNA

A novel siphovirus, vB_PagS_MED16 (MED16) was isolated in Lithuania using Pantoea agglomerans strain BSL for the phage propagation. The double-stranded DNA genome of MED16 (46,103 bp) contains 73 predicted open reading frames (ORFs) encoding proteins, but no tRNA. Our comparative sequence analysis revealed that 26 of these ORFs code for unique proteins that have no reliable identity when compared to database entries. Based on phylogenetic analysis, MED16 represents a new genus with siphovirus morphology. In total, 35 MED16 ORFs were given a putative functional annotation, including those coding for the proteins responsible for virion morphogenesis, phage–host interactions, and DNA metabolism. In addition, a gene encoding a preQ₀ DNA deoxyribosyltransferase (DpdA) is present in the genome of MED16 and the LC–MS/MS analysis indicates 2′-deoxy-7-amido-7-deazaguanosine (dADG)-modified phage DNA, which, to our knowledge, has never been experimentally validated in genomes of Pantoea phages. Thus, the data presented in this study provide new information on Pantoea-infecting viruses and offer novel insights into the diversity of DNA modifications in bacteriophages.     

Effect of thermal history on high‐valence chromium ion dissolution in merwinite (3CaO·MgO·2SiO2)

Solubility and local structure of transmission elements in calcium silicate compounds has not been well understood. We investigate the local structure of chromium ions dissolved in merwinite (3CaO·MgO·2SiO₂) of a monoclinic crystal structure. The acceptance of doping elements into merwinite has not been reported before. We found that chromium ions are soluble in merwinite in air and that chemical valence of the dissolved Cr ions varies with annealing temperature. The absorption edge in the x‐ray absorption near edge structure (XANES) of Cr‐doped merwinite indicated that octahedrally coordinated Cr³⁺ ions were mainly formed when annealed at 1673 K in air. A pre‐edge peak was also detected, indicating the existence of tetrahedrally coordinated high‐valence Cr ions. Conversely, through annealing of merwinite at 1123 K in air, tetrahedrally coordinated Cr⁶⁺ ions were found to be the main form of chromium. XANES spectra simulated by first‐principle calculations were used to explain the structural features in the observed spectra. We propose the coexistence of Cr³⁺ ions in octahedral Mg²⁺ sites and high‐valence Cr ions in tetrahedral Si⁴⁺ sites. In addition, a change in the chromium ion oxidation state in tetrahedral coordination sites was suggested by XANES spectroscopy of Cr‐doped merwinite synthesized at 1673 K and reannealed at 1123 K.     

Apron design for protecting double‐skin façade fires

Although double‐skin façade (DSF) is an environmental‐friendly architectural feature, its fire behaviour is a deep concern. The interior glass system including the glass pane, metal frame and associated accessories will be hotter than the exterior glass system as demonstrated by earlier studies. The glass pane above the fire room will be broken to spread flame into the upper compartment. Aprons are proposed to protect the air cavity of DSF in a way similar to those outside a single‐skin façade. In this paper, the effect of aprons in protecting against fire spread from an underlying compartment to the compartments above by preventing glass breakage of the inner glass pane was studied. Fire and smoke from a post‐flashover room fire adjacent to the DSF would be trapped in the air cavity between the two glass panes. Spreading of hot gases with different apron widths was studied by numerical simulations with CFD first. Fire environment with and without breaking the apron immediately above the fire room was studied. Full‐scale burning tests on part of an experimental DSF rig were then carried out to demonstrate the performance of horizontal apron in the DSF rig of 6 m tall and air cavity depth of 2 m with different apron widths. All demonstrated that providing apron is appropriate in protecting DSF fires. Copyright © 2014 John Wiley & Sons, Ltd.