Molecular dynamics simulation of ionic transport on molten Li–KCl interface

A molecular dynamics study is performed to determine the dynamics and transport properties of the ions on the molten interface between anode metal Li and electrolyte KCl. Radial distribution function of the ionic pair and the behavior of the mean‐square displacement (MSD) as a function of time (t) indicate that KCl and metal Li are in the molten state at 2,200 K in the canonical ensemble. The dynamics of the ionic transport are characterized by studying MSD for the centers of mass of the ions at different temperatures. Diffusion coefficient is evaluated from the linear slope of the MSD (t) function in the range of 0–500 ps. The MSD and diffusion coefficient of the Li⁺ ions are much larger than those of the Cl^? and K⁺ ions due to the difference in ionic characteristic. The transport process has been dominated by the Li⁺ ions on the molten interface and the Li⁺ ions are main charge carriers. The energy barrier of the Li⁺ ions transporting into the molten KCl is fitted to be 5.28 kcal/mol in the light of the activation model. The electrical conductivity of the Li⁺ ions transporting into the molten KCl are calculated from the Nernst–Einstein formula to be in the range of 0.2–0.3 S cm^?1. The current density resulted from the Li⁺ ions through the interface are estimated to be an order of 10⁶ A cm^?2, which may be the value corresponding to a larger concentration gradient of the Li⁺ ions. Simulated results at different temperatures show that the diffusion coefficient, conductivity and current density have increased with the temperature. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

Visible‐Light‐Driven Chemoselective Hydrogenation of Nitroarenes to Anilines in Water through Graphitic Carbon Nitride Metal‐Free Photocatalysis

Green and efficient procedures are essential for the chemoselective hydrogenation of functionalized nitroarenes to form industrially important anilines. Herein, it is shown that visible‐light‐driven, chemoselective hydrogenation of functionalized nitroarenes with groups sensitive to forming anilines can be achieved in good to excellent yields (82–100 %) in water under relatively mild conditions and catalyzed by low‐cost and recyclable graphitic carbon nitride. The process is also applicable to gram‐scale reaction, with a yield of aniline of 86 %. A study of the mechanism reveals that visible‐light‐induced electrons are responsible for the hydrogenation reactions, and thermal energy can also promote the photocatalytic activity. A study of the kinetics shows that this reaction possibly occurs through one‐step hydrogenation or stepwise condensation routes. A wide range of applications can be expected for this green, efficient, and highly selective photocatalysis system in reduction reactions for the synthesis of fine chemicals.     

Synthesis and Biological Activities of Diosgenin-Triazole Conjugates with a 1,3-Dipolar Cycloaddition Reaction

Chemistry of Natural Compounds - A novel series of diosgenin-triazole conjugates (10a–d, 11a–c, 12a–c, 13a–c) was designed and synthesized as antifungal agents by using a...     

Measurements of single-molecule electromechanical properties

The electromechanical properties of a single molecule covalently attached to two gold electrodes are studied by simultaneously measuring the conductance and the force during the stretching of the molecule. The conductance, the spring constant of the molecular junction, and the dependence of the conductance on the stretching force are determined. Like the conductance, the spring constant of a molecule depends also on the molecule-electrode contacts. The forces required to break the molecule-gold contacts are 1.5 nN for alkanedithiols and 0.8 nN for 4,4' bipyridine, indicating that the breakdowns take place at the Au-Au bond and at the N-Au bond, respectively.     

ADSORPTION OF SULFOXIDES ON SOLID FROM AQUEOUS SOLUTIONS Ⅲ.THE ADSORPTION ON CARBON BLACK

The adsorption of decylmethylsulfoxide (DEMS) onto carbon black and the effects of temperature, salt (NaCl) and acid (HCl) have been measured.Typical two plateaux type adsorption isotherms were obtained. Applying the two step model of surfactant adsorption on solid/liquld interface and the general adsorption isotherm equation[9]the experimental results were interpreted qualitatively and quantitatively.     

铌(V)-1-苯基-3-甲基-4-苯甲酰基-吡唑啉酮-5络合物吸附波的研究

在pH=5.0的HAc-NaAc介质中,Nb(V)与1-苯基-3-甲基-4-苯甲酰基-吡唑啉酮-5(PMBP)生成络合物,于-0.96V(us.SCE)出现一尖锐的极谱波.在滴汞电极上用示波极谱仪或在悬汞电极上测吸附伏安曲线.峰电流与Nb(V)浓度分别在0.0075~0.80μg/mL及0.000075~0.0075μg/mL范围内呈线性关系.实验了30多种离子的干扰影响,经苯肿酸分离后用于钢中Nb(V)的测定.检出限为0.00003μg/mL.溶液可稳定96h以上.用多种电化学方法研究了电极反应机理.     

A Luminescent Cage‐Like Complex Constructed by Bidentate Pyridine‐Containing Ligand and Silver Nitrate

The cage‐like complex, Ag₄L₄(NO₃)₄ ( 1 ) [L = 1, 4‐bis(pyridine‐2‐ylmethoxy)benzene] was synthesized by the reaction of the flexible bidentate ligand and silver nitrate. It was characterized by elemental analysis, IR spectroscopy, TG, and single‐crystal X‐ray analysis. Complex 1 is reported as the first cage‐like cluster constructed by four nitrate anions bridging two [2+2] macrocycles. A blue luminescent emission and luminescent enhancement effect are observed in complex 1 .     

聚硅氧烷富勒烯固相微萃取涂层的性能

高分子聚硅氧烷富勒烯首次被用作固相微萃取涂层材料,利用顶空固相萃取气相色谱法对该涂层进行了评价。与商用的聚二甲基硅氧烷相比,自制涂层在选择性、灵敏度、热稳定性、使用寿命及萃取量等方面的性能均优于商用聚二甲基硅氧烷。     

Quantum yields of luminescent lanthanide chelates and far-red dyes measured by resonance energy transfer.

Luminescent lanthanide chelates have unusual spectroscopic characteristics that make them valuable alternative probes to conventional organic fluorophores. However, fundamental parameters such as their quantum yield, and radiative and nonradiative decay rates have been difficult or impossible to measure. We have developed a simple and robust method based on resonance energy transfer to accurately measure these parameters. In addition, the excitation/emission process in lanthanide chelates involves several steps, and we are able to quantify each step. These include excitation of an organic antenna, transfer of energy from the antenna to lanthanide, and then lanthanide emission. Overall, the parameters show that lanthanide chelates can be efficient long-lived emitters, making them sensitive detection reagents and excellent donors in resonance energy transfer. The method is also shown to be applicable to photophysical characterization of red-emitting dyes, which are difficult to characterize by conventional means.