Effect of solvent on the construction of Co(II) coordination polymers containing a semi-rigid bis(benzimidazole) derivative: syntheses,structures, and properties

Two Co(II) coordination polymers, [CoL(npa)]·2H₂O (1) and [CoL(Hnpa)₂] (2) (L = 1,4-bis(5,6-dimethylbenzimidazole-1-yl)benzene, H₂npa = 5-nitroisophthalic acid), have been synthesized in different solvent systems and characterized by Infrared (IR) spectroscopy, elemental analysis, and powder and single crystal X-ray diffraction. Compound 1 was synthesized under solvothermal conditions with DMF as solvent and had a pair of L ligands adopting a μ₂-bridging mode and connecting two Co²⁺ cations to generate a 26-membered Co₂L₂ loop. The npa^2? link adjacent Co₂L₂ loops via a bis(monodentate) bridging mode to create a 1-D channel-like chain structure. Compound 2 was obtained under hydrothermal conditions, and the carboxylate of the monodeprotonated Hnpa^? adopt a μ₁-η^0?:?η¹ coordination to connect adjacent Co²⁺ cations into a 2-D polymeric layer. The μ₂-bridging L ligands connect adjacent 2-D [Co(Hnpa)]_n polymeric layers into a 3-D NaCl-like framework. The Co²⁺ cations and the L ligands in compounds 1 and 2 exhibit different coordination geometries and conformations. Effects of solvents on the construction of Co(II) coordination polymers were investigated. In addition, the electrochemical behavior of carbon paste electrodes containing 1 and 2 and the thermal stabilities of 1 and 2 were investigated.     

Corrosion inhibition of ammonium molybdate for AA6061 alloy in NaCl solution and its synergistic effect with calcium gluconate

The corrosion inhibition of ammonium heltamolybdate (AH) and calcium gluconate (CG) for AA6061 alloy in 3% NaCl solution was investigated by the electrochemical measurements. It indicates that AH inhibits the corrosion of AA6061 alloy and acts as an anodic inhibitor. Maximum inhibition efficiency reaches 74.3% at the concentration of 1 × 10^?4 mol.l^?1 AH. The results of the electrochemical studies reveal AH is physically adsorbed on the AA6061 alloy surface and the adsorption follows Langmuir isotherm. The combination of AH and CG enhances the inhibition efficiency to 95.9%. The enhanced inhibition is attributed to the promotion of AH adsorption by CG. The mixture of AH and CG is a mixed‐type inhibitor and renders the corrosion potential to more positive values. Copyright © 2011 John Wiley & Sons, Ltd.     

Liquid–liquid extraction of copper(II) with substituted salicylideneanilines from sulfate media

The liquid–liquid extraction of copper(II) with Schiff bases in chloroform from sulfate media is studied for pH and concentration of the extractant. Stoichiometry coefficients of the extracted species are determined by the slope analysis method. With salicylideneaniline, the copper(II) is extracted as a mixed chelate complex, CuL₂HL. In the presence of substituent, the copper is extracted as simple chelates, CuL₂. The trends in the values of extraction constants were explained in terms of the nature of the substituents.     

再散射输运模型与K+/π+比的系统学

用含再散射效应的简单的强子输运模型,研究了AGS能量(14.6AGeV/c)下p+p、p+Au和Si+Au反应的K⁺/π⁺比值,再现了该比值由P十P到Si十Au不断增长的实验事实.CERN能量(200AGeV/c)和AGS能量下,K⁺/π⁺比值相近的实验事实也得到了解释.     

利用不完全自锁模激光研究C60的反饱和吸收效应

本文报道首次采用色心晶体的不完全自锁模激光（１０６４ｎｍ）对Ｃ６０分子反饱和吸收效应的研究，实验结果与采用平均过程的研究方法是一致的，文中还讨论了Ｃ６０分子反饱和吸收效应产生的原因。     

Traveling－Wave Electrooptical Modulator on Polymeric Film with Reversal Poling Structure

Ｔｒａｖｅｌｉｎｇ－ＷａｖｅＥｌｅｃｔｒｏｏｐｔｉｃａｌＭｏｄｕｌａｔｏｒｏｎＰｏｌｙｍｅｒｉｃＦｉｌｍｗｉｔｈＲｅｖｅｒｓａｌＰｏｌｉｎｇＳｔｒｕｃｔｕｒｅ￥ＺＨＯＵＹｉ；ＣＨＥＮＹｉｘｉｎ（ＤｅｐａｒｔｍｅｎｔｏｆＡｐｐｌｉｅｄＰｈｙｓｉｃｓ，Ｓ...     

核压力容器防止辐照脆化的安全评定

本文结合我国核动力反应堆的实例,首先介绍了设计规范中采用的断裂分析图的评定方法,然后着重讨论一种新的断裂力学的评定方法。结合对容器材料断裂韧性的实验测定,给出了计算结果,绘制了全寿期的安全运行工况图,并对两种方法的结果作了比较讨论。     

COF-42:一种理想的锂硫电池锚定材料

寻找理想的锚定材料抑制穿梭效应是锂硫电池面临的重要问题之一.本文采用密度泛函方法,研究了四种共价有机框架COFs材料(COF-1,CTF-1,COF-LZU1和COF-42)和硫锂化合物(Li_2S_n)的作用机理.通过分析吸附构型、吸附能、电子密度差分以及态密度等性质,发现COFs材料与硫锂化合物的化学吸附作用主要源于COFs表面极性N和O原子与Li之间的静电作用力.在COF-42/Li_2S_n吸附构型中,N和O原子与Li之间形成双重类离子键;电子密度差分和Bader电荷差分表明,与其他COFs材料相比,Li_2S_n和COF-42之间电荷转量最多,因此,COF-42具有最强的锚定作用.比较Li_2S_n和COF-42以及常用电解质分子1,3-二氧戊环(DOL)和二甲氧基乙烷(DME)的吸附能,证明COF-42可以抑制电解质分子的溶剂化作用; COF-42与COF-1,CTF-1和COF-LZU1相比较,具有良好导电性.因此,COF-42可能是一种理想的锂硫电池锚定材料.     

Efimov's Effect in a Model of Perturbation Theory of the Essential Spectrum

A model operator similar to the energy operator of a system with a nonconserved number of particles is studied. The essential spectrum of the operator is described, and under some natural conditions on the parameters it is shown that there are infinitely many eigenvalues lying below the bottom of the essential spectrum.