Germaborenes: Borylene Transfer Agents for the Synthesis of Iminoboranes

Halide and phenyl substituted germaborenes were shown to react with azides at room temperature and transfer a borylene moiety to give iminoboranes. This iminoborane synthesis based on a borylene transfer route was investigated computationally in the case of the phenyl substituted germaborene.     

Preparation of hybrid microcapsules and application to self‐healing agent

It was tried to prepare hybrid microcapsules composed of porous inorganic particles and epoxy resin shell and to apply to the self‐healing agent. A water soluble imidazole of gelation promoting agent as the core material was microencapsulated in the porous inorganic particles, which were coated with epoxy resin. The porous inorganic particles were prepared with the interfacial reaction between sodium silicate and calcium ion in the (W/O) dispersion. In the experiment, the concentration of sodium silicate and the mixing speed to form the (W/O) dispersion were mainly changed. The porous inorganic particles were immersed in the aqueous solution dissolving imidazole and then, added in the corn oil dissolving epoxy resin to be microencapsulated with gelated epoxy resin. The hybrid microcapsules containing imidazole with the mean diameters from 200 to 400 µm were able to be prepared and to induce the gelation reaction of epoxy resin by breaking the hybrid microcapsule shell due to heating. Copyright © 2013 John Wiley & Sons, Ltd.     

Determination of conditional stability constants for some divalent transition metal ion‐EDTA complexes by electrospray ionization mass spectrometry

Conditional stability constants of coordination complexes comprising divalent transition metals, Cu²⁺, Ni²⁺, Zn²⁺, Co²⁺, and ethylenediaminetetraacetic acid (EDTA) were determined utilizing electrospray ionization mass spectrometry. The deviation of signal response of a reference complex was monitored at addition of a second metal ion. The conditional stability constant for the competing metal was then determined through solution equilibria equations. The method showed to be applicable to a system where Co²⁺ and Zn²⁺ competed for EDTA at pH 5. When Cu²⁺ and Ni²⁺ competed for EDTA, the equilibrium changed over time. This change was shown to be affected in rate and size by the type of organic solvent added. In this work, 30% of either methanol or acetonitrile was used. It was found that if calibration curves are prepared for both metal complexes in solution and the measurements are repeated with sufficient time space, any change in equilibrium of sample solutions will be discovered. Copyright © 2014 John Wiley & Sons, Ltd.     

Alkyl Ammonium Cation Stabilized Biocidal Polyiodides with Adaptable High Density and Low Pressure

The effective application of biocidal species requires building the active moiety into a molecular back bone that can be delivered and decomposed on demand under conditions of low pressure and prolonged high‐temperature detonation. The goal is to destroy storage facilities and their contents while utilizing the biocidal products arising from the released energy to destroy any remaining harmful airborne agents. Decomposition of carefully selected iodine‐rich compounds can produce large amounts of the very active biocides, hydroiodic acid (HI) and iodine (I₂). Polyiodide anions, namely, I₃^?, I₅^?, which are excellent sources of such biocides, can be stabilized through interactions with large, symmetric cations, such as alkyl ammonium salts. We have designed and synthesized suitable compounds of adaptable high density up to 3.33 g cm^?3 that are low‐pressure polyiodides with various alkyl ammonium cations, deliverable iodine contents of which range between 58.0–90.9 %.     

Efficient Biocatalytic Degradation of Pollutants by Enzyme‐Releasing Self‐Propelled Motors

The first example of a self‐propelled tubular motor that releases an enzyme for the efficient biocatalytic degradation of chemical pollutants is demonstrated. How the motors are self‐propelled by the Marangoni effect, involving simultaneous release of SDS surfactant and the enzyme remediation agent (laccase) in the polluted sample, is illustrated. The movement induces fluid convection and leads to the rapid dispersion of laccase into the contaminated solution and to a dramatically accelerated biocatalytic decontamination process. The greatly improved degradation efficiency, compared to quiescent solutions containing excess levels of the free enzyme, is illustrated for the efficient biocatalytic degradation of phenolic and azo‐type pollutants. The high efficiency of the motor‐based decontamination approach makes it extremely attractive for a wide‐range of remediation processes in the environmental, defense and public health fields.     

Observation of Unusual Molecular Diffusion Behaviour below the Lower Critical Solution Temperature of Water/2‐Butoxyethanol Mixtures by using Fluorescence Correlation Spectroscopy

The effect of solute affinity on solute diffusion in binary liquids well below the lower critical solution temperature (LCST) was studied by using fluorescence correlation spectroscopy. We measured the hydrodynamic radii of a hydrophobic and an amphiphilic fluorescent dye under systematic variation of the relative molar fractions of water/2‐butoxyethanol and, for comparison, of water/methanol mixtures, which do not show phase separation. We found that the apparent hydrodynamic radius of the hydrophobic dye almost doubled in water/2‐butoxyethanol, whereas it remained largely unchanged for the amphiphilic dye and in water/methanol mixtures. Our results indicate that the translational diffusion of solutes is influenced by transient local solution structures, even at temperatures well below the LCST. We conclude that, even far below LCST, different solutes can experience different environments in binary liquid mixtures depending on both the solute and solvent properties, all of which impact their reactivity.     

Qualitative spectroscopic characterization of the matrix–silane coupling agent interface across metal fibre reinforced ion exchange resin composite membranes

The characterization of novel metal reinforced electro-dialysis ion exchange membranes, for water desalination, by attenuated total reflectance Fourier transform infrared spectroscopy mapping is presented in this paper. The surface of the porous stainless steel fibre meshes was treated in order to enhance the amount of surface oxide groups and increase the material hydrophilicity. Then, the metal membranes were functionalized through a sol–gel reaction with silane coupling agents to enhance the affinity with the ion exchange resins and avoid premature metal oxidation due to redox reactions at the metal–polymer interface. Polished cross sections of the composite membranes embedded into an epoxy resin revealed interfaces between metallic frameworks and the silane layer at the interface with the ion exchange material. The morphology of the metal–polymer interface was investigated with scanning electron microscopy and Fourier transform infrared micro-spectroscopy. Fourier transform infrared mapping of the interfaces was performed using the attenuated total reflectance mode on the polished cross-sections at the Australian Synchrotron. The nature of the interface between the metal framework and the ion exchange resin was shown to be homogeneous and the coating thickness was found to be around 1 μm determined by Fourier transform infrared micro-spectroscopy mapping. The impact of the coating on the properties of the membranes and their potential for water desalination by electro-dialysis are also discussed.     

丙烯腈、己二腈和丙腈与水的二元体系液-液相平衡数据的测定和关联(英文)

采用平衡法测定了丙烯腈+水、己二腈+水、丙腈+水三个二元体系在不同温度(303.15、313.15、323.15、333.15K)下的液-液相平衡数据;并采用NRTL(α=0.2,α=0.3)模型和UNIQUAC模型对液-液平衡数据进行了关联.结果显示,NRTL和UNIQUAC模型对三个二元体系在不同温度下的互溶度关联的目标函数值均小于1×10-17,实验值与计算值吻合较好,绝对偏差小于0.009,关联精度较高.该研究结果可为丙烯腈、丙腈和水三元平衡溶解度数据的模拟和预测提供可靠的基础数据,并对电解二聚法生产己二腈中电解液的分离提纯工艺具有一定的指导意义.     

Exploring the Limits of Transition-Metal Fluorination at High Pressures

Fluorination is a proven method for challenging the limits of chemistry, both structurally and electronically. Here we explore computationally how pressures below 300 GPa affect the fluorination of several transition metals. A plethora of new structural phases are predicted along with the possibility for synthesizing four unobserved compounds: TcF₇, CdF₃, OsF₈, and IrF₈. The Ir and Os octaflourides are both predicted to be stable as quasi-molecular phases with an unusual cubic ligand coordination, and both compounds formally correspond to a high oxidation state of +8. Electronic-structure analysis reveals that otherwise unoccupied 6p levels are brought down in energy by the combined effects of pressure and a strong ligand field. The valence expansion of Os and Ir enables ligand-to-metal F 2p→M 6p charge transfer that strengthens M−F bonds and decreases the overall bond polarity. The lower stability of IrF₈, and the instability of PtF₈ and several other compounds below 300 GPa, is explained by the occupation of M−F antibonding orbitals in octafluorides with a metal-valence-electron count exceeding 8.     

In Situ Pyrolysis Tracking and Real-Time Phase Evolution: From a Binary Zinc Cluster to Supercapacitive Porous Carbon

The in situ tracking of the pyrolysis of a binary molecular cluster [Zn₇(μ₃-CH₃O)₆(L)₆][ZnLCl₂]₂ is presented with one brucite disk and two mononuclear fragments (L=mmimp: 2-methoxy-6-((methylimino)-methyl)phenolate) to porous carbon using TG-MS from 30 to 900 °C. Following up the spilled gas product during the decomposed reaction of zinc cluster along the temperature rising, and in conjunction with XRD, SEM, BET and other materials characterization, where three key steps were observed: 1) cleavage of the bulky external ligand; 2) reduction of ZnO and 3) volatilization of Zn. The real-time-dependent phase-sequential evolution of the remaining products and the processing of pore forming template transformation are proposed simultaneously. The porous carbon structure featuring a uniform nano-sized pore distribution synthesized at 900 °C with the highest surface area of 1644 m² g⁻¹ and pore volume of 0.926 cm³ g⁻¹ exhibits the best known capacitance of 662 F g⁻¹ at 0.5 A g⁻¹.