Electrocatalytic reduction of carbon dioxide by a polymeric film of rhenium tricarbonyl dipyridylamine

A dipyridylamine ligand with a pendant pyrrole (N-(3-N,N′-bis(2-pyridyl)propylamino)pyrrole, PPP) and its corresponding rhenium(I) complex, Re(CO)₃(κ²-N,N-PPP)Cl, were synthesized. The structure of Re(CO)₃(κ²-N,N-PPP)Cl was determined by X-ray crystallography. Electrochemical polymerization of the pyrrole moiety resulted in the immobilization of poly[Re(CO)₃(κ²-N,N-PPP)Cl] film onto a glassy carbon electrode, which exhibited electrocatalytic activity for the reduction of CO₂ to CO.     

Electronic Structure and Optical Properties of Antimony-Doped SnO_2 from First-Principle Study

A first-principles study has been performed to calculate the electronic and optical properties of the SbxSn1xO system.The simulations are based upon the method of generalized gradient approximations with the Perdew-Burke-Ernzerhof form in the framework of density functional theory.The supercell structure shows a trend from expanding to shrinking with the increasing Sb concentration.The increasing Sb concentration induces the band gap narrowing.Optical transition has shifted to the low energy range with increasing Sb concentration.Other important optical constants such as the dielectric function,reflectivity,refractive index,and electron energy loss function for Sb-doped SnO2 are discussed.The optical absorption edge of SnO2 doped with Sb also shows a redshift.     

Free energy and scalings for polymer translocation through a nanopore: A molecular dynamics simulation study combined with milestoning

Coarse-grained molecular dynamics simulations combined with milestoning method are used to study the stochastic process of polymer chain translocation though a nanopore. We find that the scalings for polymer translocation process (the chain is initialized with the first monomer in the nanopore) and for polymer escape process (the chain is initialized with the middle monomer in the nanopore) are different. The translocation process is mainly controlled by the entropic barrier, while the polymer escape process is driven by the effective force due to free energy difference.     

半Heusler型拓扑绝缘体LaPtBi能带调控的研究

采用基于密度泛函理论的全势能线性缀加平面波的方法, 研究了化学替代和施加等体积单轴(拉、压)应力两种方式对半Heusler型拓扑绝缘体LaPtBi能带的影响. 计算结果表明, 通过在LaPtBi合金中用Sc元素替换La, 或者用Pd替换Pt, 都可以使得原本受立方对称性保护的Γ₈能带在费米能级附近打开一带隙; 而对于施加等体积单轴应力来扭曲立方晶格的方式, 在使得Γ₈ 能带打开的同时, 还可以实现对费米能级位置有规律地调控, 使 LaPtBi合金最终成为真正意义上的体材料是绝缘性而表面是金属性的拓扑绝缘体.     

[Co(2,3-tri)(amp)Cl][ZnCl4]体系中部分几何经式异构体的结构测定

利用单晶X-射线衍射分析了[Co(2,3-tri)(amp)Cl][ZnCl4](2,3-tri=N-(2-Aminoethvl)-1,3-propanediamine;amp=2-(Aminomethyl)pyridine)体系中的一异构体(m3-[Co(2,3-tri)(amp)Cl][ZnCl4]@2.5H2O)结构,用二维核磁共振DQCOSY和NOESY技术联合解析了另两个异构体(m2-[Co(2,3-tri)(amp)C1][ZnCl4]及m4-[Co(2,3-tri)(amp)Cl]][ZnCl4])在溶液中的结构.结构解析显示它们为该体系的三个几何经式异构体.解析的晶体结构属中心对称的空间群,表明它是外消旋的对映体.     

[(phen)2Mn2(μ-O)(μ-Ac)2(H2O)2](ClO4)2·4H2O双核锰配合物的合成、晶体结构及性质

MnAc3.2H2O在pH=4.0的HAc-NaAc缓冲溶液中和邻菲罗啉(phen)反应, 制得了双核锰(Ⅲ)合物[(phen)2Mn2(μ-O)(μ-Ac)2 (H2O)2](ClO4)2.H2O, 并进行了红外光谱表征. X射线单晶衍射表明, 该晶体属单斜晶系, 空间群P21/n, 晶胞参数: a=1.025 28(5) nm, b=1.792 75(9) nm, c=1.984 14(10) nm, β=94.843 0(10)°, V=3.634 0(3) nm3, Z=4, Dc=1.669 g.cm-3. 紫外可见光谱在480 nm处有一个吸收峰. 循环伏安实验说明, 此配合物在乙腈溶液中经历了一个半可逆的一电子氧化还原过程.     

沙蚕磷草酸盐的合成与晶体结构

合成了一种新的有机磷杀虫剂沙蚕磷[O,O,O',O'-四甲基－S,S'-(2-N,N-二甲氨基-1,3-亚丙基)-双-二硫代磷酸酯],并制备了它的草酸盐。测定了沙蚕磷草酸盐的晶体结构,结果表明,该晶体属三斜晶系,P1空间群,晶胞参数为:a=0.74342(5)nm,b=1.1057(4)nm,c=1.45295(11)nm,α=98.018(11)°,β=101.012(4)°,γ=96.224(10)°,Z=2。通过元素分析,MS、IR及^1H,^1^3CNMR表征了该化合物的结构。     

Strain distributions and electronic structure of three-dimensional InAs/GaAs quantum rings

This paper presents a finite element calculation for the electronic structure and strain distribution of self-organized InAs/GaAs quantum rings. The strain distribution calculations are based on the continuum elastic theory. An ideal three-dimensional circular quantum ring model is adopted in this work. The electron and heavy-hole energy levels of the InAs/GaAs quantum rings are calculated by solving the three-dimensional effective mass Schr?dinger equation including the deformation potential and piezoelectric potential up to the second order induced by the strain. The calculated results show the importance of strain and piezoelectric effects, and these effects should be taken into consideration in analysis of the optoelectronic characteristics of strain quantum rings.     

双原子分子激发态势能的自旋相关局域Hartree-Fock密度泛函理论方法

基于自旋相关局域Hartree-Fock (SLHF)势函数,本文提出了一种计算双原子分子激发态势能的密度泛函理论(DFT)方法,并将该方法应用于和的激发态势能曲线的计算。在只考虑交换能的情况下,本文的DFT计算结果与文献中精确方法和Hartree-Fock (HF)方法的结果符合的非常好,说明采用SLHF势函数作为交换势的DFT方法是一个很好的计算激发态势能的方法。本文还计算和探讨了电子的关联势函数和关联能,发现传统的近似方法在较大核间距的情况下大大低估了电子的关联能.     

聚乙烯在羟基化β-石英(100)表面上的有序吸附

利用分子动力学模拟方法研究了聚乙烯链在羟基化β-石英(100)表面上的吸附. 结果表明, 吸附基底上的规则图案起到模板的作用, 无论是真空还是溶液环境, 都会引导聚乙烯链在表面形成二维沿着[110]方向取向的折叠构型. 为了与聚乙烯的吸附相比较, 进一步研究了聚氧化乙烯链在相同表面上的吸附情况. 结果表明, 极性链与非极性链在极性表面上的吸附情况完全不同.