Three‐dimensional hydrogen‐bonded framework structures in flunarizinium nicotinate and flunarizinediium bis(4‐toluenesulfonate) dihydrate

The structures of two salts of flunarizine, namely 1‐bis[(4‐fluorophenyl)methyl]‐4‐[(2E)‐3‐phenylprop‐2‐en‐1‐yl]piperazine, C₂₆H₂₆F₂N₂, are reported. In flunarizinium nicotinate {systematic name: 4‐bis[(4‐fluorophenyl)methyl]‐1‐[(2E)‐3‐phenylprop‐2‐en‐1‐yl]piperazin‐1‐ium pyridine‐3‐carboxylate}, C₂₆H₂₇F₂N₂⁺·C₆H₄NO₂⁻, (I), the two ionic components are linked by a short charge‐assisted N—H...O hydrogen bond. The ion pairs are linked into a three‐dimensional framework structure by three independent C—H...O hydrogen bonds, augmented by C—H...π(arene) hydrogen bonds and an aromatic π–π stacking interaction. In flunarizinediium bis(4‐toluenesulfonate) dihydrate {systematic name: 1‐[bis(4‐fluorophenyl)methyl]‐4‐[(2E)‐3‐phenylprop‐2‐en‐1‐yl]piperazine‐1,4‐diium bis(4‐methylbenzenesulfonate) dihydrate}, C₂₆H₂₈F₂N₂²⁺·2C₇H₇O₃S⁻·2H₂O, (II), one of the anions is disordered over two sites with occupancies of 0.832 (6) and 0.168 (6). The five independent components are linked into ribbons by two independent N—H...O hydrogen bonds and four independent O—H...O hydrogen bonds, and these ribbons are linked to form a three‐dimensional framework by two independent C—H...O hydrogen bonds, but C—H...π(arene) hydrogen bonds and aromatic π–π stacking interactions are absent from the structure of (II). Comparisons are made with some related structures.     

Synthesis and characterization of a new organically templated open-framework beryllium phosphite with 3, 4-connected networks

Employing diethylenetriamine (=dien) as a structure-directing agent, a new open-framework beryllium phosphite H₂dien·Be₃(HPO₃)₄ (1), has been synthesized hydrothermally and structurally characterized by single crystal X-ray diffraction. The structure of 1 features a (3, 4)-connected framework with 8- and 12-ring channels, which is constructed from strictly alternating BeO₄ tetrahedra and HPO₃²⁻ pseudopyramids. The 3-D framework possesses a pcu topology when the heptameric [Be₃(HPO₃)₄] clusters are regarded as 6-connected secondary building units. Crystal data: 1, monoclinic, C2/c (no. 15), a = 8.7350(3) Å, b = 15.1704(6) Å, c = 13.0851(4) Å, β = 101.223(5)°, V = 1700.79(10) Å³, Z = 4, R₁ = 0.0625, wR₂ = 0.1692.     

Bi‐channel Surface Acoustic Wave Gas Sensor for Carbon Disulfide and Methanol Vapors in Polymer Plants

A C₆₀‐polyphenylacetylene (C₆₀‐PPA) and polyvinylpyrrolidone (PVP) coated two‐channel surface acoustic wave (SAW) crystal gas sensor with a homemade computer interface for data acquisition and data processing was developed and employed to detect carbon disulfide (CS₂) and methanol (CH₃OH) vapors in polymer plants. The frequency of surface acoustic wave oscillator decreases due to the adsorption of gas molecules on the coated materials of the SAW sensor. Six coating materials (C₆₀‐PPA, nafion, PPA, crytand [2,2], polyethene glycol and PVP) were used to adsorb and detect carbon disulfide and methanol gases. Adsorption of all the six coating materials to CS₂ and CH₃OH was found to be physical adsorption. The C₆₀‐PPA coated SAW detector exhibited more sensitive to CS₂ than the other coating materials. In contrast, the PVP coated SAW detector was more sensitive to CH₃OH than the other coating materials. With the two‐channel SAW sensor, the C₆₀‐PPA coated SAW showed a good detection limit of 0.4 ppm and good reproducibility with RSD of 3.37 % (n=10) for CS₂. Similarly, the PVP coated SAW also showed a good detection limit of 0.05 ppm and good reproducibility, with RSD of 0.86 % (n=10) for CH₃OH. The interference effect of other organic molecules on the SAW detection system was negligible, except for the irreversible adsorption of C₆₀‐PPA to propylamine. The frequency signals from the two‐channel SAW sensor array C₆₀‐PPA and PVP coatings were processed by a back‐propagation artificial neural network (BPN) and multiple regression analysis (MRA). Thus a two‐channel SAW sensor array with BPN and MRA has been successfully applied for the qualitative and quantitative analyses of CS₂ and CH₃OH in mixtures.     

CH3(2A′)自由基与臭氧反应机理的量子化学研究

用量子化学UMP2方法，在6-311++G**基组水平上研究了CH3(2A′)自由基与臭氧反应机理，全参数优化了反应过程中反应物、中间体、过渡态和产物的几何构型，在UQCISD(T)/6-311++G**水平上计算了它们的能量；并对它们进行了振动分析，以确定中间体和过渡态的真实性；同时应用经典过渡态理论计算了反应的速率常数，并与实验值进行了比较, CH3自由基与臭氧反应速率常数的理论计算结果为: 4.73×10－14 cm3•molecule－1•s－1，与实验报导的结果(k=2.52×10－14 cm3•molecule－1•s－1)很接近，同时发现CH3(2A′)自由基与O3的反应是强放热反应.     

Stochastic nanopore sensors for the detection of terrorist agents: Current status and challenges

Nanopore stochastic sensor works by monitoring the ionic current modulations induced by the passage of analytes of interest through a single pore, which can be obtained from a biological ion channel by self-assembly or artificially fabricated in a solid-state membrane. In this minireview, we overview the use of biological nanopores and artificial nanopores for the detection of terrorist agents including explosives, organophosphorus nerve agents, nitrogen mustards, organoarsenic compounds, toxins, and viruses. We also discuss the current challenge in the development of deployable nanopore sensors for real-world applications.     

毛细管电泳多道电化学检测器的研制及其应用

报道了毛细管电泳多道电化学检测器的研制及其应用，安培检测器和电导检测器并联在同一毛细管电泳检测系统中，在同一缓冲体系，同一工作电极下对同一复杂的分析体系同时进行电导和安培检测；整个装置综合了电导检测和安培检测两种检测器的优点，性能优良，造价低廉，对实际样品的检测取得了令人满意的结果。     

Synthesis,Properties and Crystal Structure of a New Bismuth Oxalate： Na（C5NH6） [Bi（H2O）（C2O4）2]2·4H2O

A new bismuth oxalate Na（C5NH6）[Bi（H2O）（C2O4）2]2·4H2O has been obtained under hydrothermal conditions and characterized by X-ray diffraction. It crystallizes in monoclinic, space group C2/m with a = 12.020（5）, b = 11.190（8）, c = 11.067（10）A, β= 121.78（2）°, NaBi2C13NH18O22, Mr= 981.24, V = 1265.4（16） A^3, Z = 2, Dc = 2.575 g/cm^3,μ（MoKcr） = 14.005 mm^-1, F（000） = 912, R = 0.0179 and wR = 0.0394. In the structure, the Bi（III） centers are interconnected by oxalate ligands to produce honeycomb-like layers, which are further pillared by bridging ligand oxalate molecules to form a 3-D open-framework structure. Furthermore, the title compound exhibits blue luminescence with the emission peaks located at 394nm in the solid state at room temperature, and thus it could be useful in the field of photoactive materials.     

采用分子动力学模拟方法评价人类VDAC通道蛋白晶体结构的生物活性

电压依赖阴离子选择性通道（Voltage dependent anion-selective channel, VDAC）是线粒体外膜上重要的通道蛋白,转运线粒体和细胞质之间的代谢物,对于线粒体发挥生理功能具有决定性作用. 为研究VDAC分子的调控机制,在电场存在和不存在的情况下,我们对I型人类VDAC分子（hVDAC1）分别进行了分子模拟研究. 比较结果显示：外加电场的有无与方向变化对hVDAC1分子的运动模式和离子通过过程影响不明显,hVDAC1分子仍然保持以N端α螺旋在β桶内横向运动为主的运动模式. 综合模拟结果和相关的实验结果,我们推测,发表的hVDAC1晶体结构可能不是其发挥生理功能的结构状态.