三核钌簇合物[PyCH=C(Ph)O]2Ru3(CO)8的合成、结构及反应性

配体PyCH₂COPh与Ru₃（CO）₁₂在甲苯中加热回流,得到了标题簇合物[PyCH=C（Ph）O]₂Ru₃（CO）₈（1）。通过红外光谱、核磁共振氢谱和碳谱对1的结构进行了表征,用X射线单晶衍射法测定了1的结构。结果表明：3个钌原子呈等腰三角形分布,其中Ru（2）-Ru（1）和Ru（2）-Ru（1）ⁱ的键长均为0.280 nm,Ru（1）-Ru（1）ⁱ的键长为0.307 nm。同时研究了簇合物1与环戊二烯及茚的反应,分别得到双核钌羰基配合物[（η⁵-C₅H₅）Ru（CO）]₂（μ-CO）₂（2）和[（η⁵-C₉H₇）Ru（CO）]₂（μ-CO）₂（3）。     

苯基或联苯基桥连双环戊二烯基铼羰基化合物的合成、结构及催化性能

两个单桥连的双环戊二烯（C₅Me₄H） E（C₅Me₄H）（E=C₆H₄,（C₆H₄）₂）分别与Re₂（CO）₁₀在均三甲苯中加热回流,得到了2个双核配合物（E）[（η⁵-C₅Me₄） Re（CO）₃]₂（E=C₆H₄（1）,（C₆H₄）₂（2））。通过元素分析、红外光谱、核磁共振氢谱和碳谱对配合物1和2的结构进行了表征,用X射线单晶衍射分析测定了配合物的结构。同时对2个配合物在芳香族化合物Friedel-Crafts酰基化反应中的催化活性进行了研究。     

Endp oint Estimates for Commutators of Fractional Integrals Asso ciated to Op erators with Heat Kernel Bounds

Let L be the infinitesimal generator of an analytic semigroup on L~2(R~n)with pointwise upper bounds on heat kernel,and denote by L~(-α/2)the fractional integrals of L.For a BMO function b(x),we show a weak type Llog L estimate of the commutators [b,L~(-α/2)](f)(x) = b(x)L~(-α/2)(f)(x)-L~(-α/2)(bf)(x).We give applications to large classes of differential operators such as the Schr¨odinger operators and second-order elliptic operators of divergence form.     

烃基取代茚基钌羰基化合物的合成及晶体结构(英文)

配体C9H7R(R=CH2CH2CH3(1),CH(CH3)2(2),C5H9(3),CH2C6H5(4),CH2CH=CH2(5))分别与Ru3(CO)12在二甲苯或庚烷中加热回流,得到了6个双核配合物[(η5-C9H6R)Ru(CO)(μ-CO)]2(R=CH2CH2CH3(6),CH(CH3)2(7),C5H9(8),CH2C6H5(9),CH2CH=CH2(10))和[(η5-C9H6)(H3CH2C)CHCH(CH2CH3)(η5-C9H6)][Ru(CO)(μ-CO)]2(11)。通过元素分析、红外光谱、核磁共振氢谱对配合物的结构进行了表征,并用X-射线单晶衍射法测定了配合物6,9,10和11的结构。     

基于N-乙酰-L-半胱氨酸修饰的ZnFe2O4@SiO2纳米材料手性识别酪氨酸对映异构体

我们将N-乙酰-L-半胱氨酸（NALC）修饰于ZnFe₂O₄@SiO₂纳米材料表面,制备了一种新型的手性纳米复合物（ZnFe₂O₄@SiO₂-NALC）,该材料能够简便、快速及高选择性地识别手性酪氨酸（Tyr）对映体。利用X射线粉末衍射（XRD）、红外光谱（FT-IR）、能量色散X射线光谱（EDS）、扫描电子显微镜（SEM）、高分辨率透射电子显微镜（HRTEM）和振动样品磁力计（VSM）等一系列表征手段对首次合成出的ZnFe₂O₄@SiO₂-NALC进行测试表征,并将其应用于对手性识别领域的探究。实验结果表明,利用光谱技术（紫外-可见光谱和荧光光谱）,ZnFe₂O₄@SiO₂-NALC可对Tyr对映异构体进行手性识别。此外,我们进一步对Tyr浓度和pH值等实验参数进行了优化。     

New antituberculosis drugs targeting the respiratory chain

With the emergence of multidrug-resistant tuberculosis and extensive drug-resistant tuberculosis strains,there is an urgent need to develop novel drugs for the treatment of tuberculosis.The respiratory chain is a promising target for the development of newantimycobacterial agents,and a growing number of compounds have been reported and some have entered clinical trials.In this review,we summarize the main features and the electron transfer process of the mycobacterial respiratory chain,and the recent progress in the search for new small molecule inhibitors to rgeting the three main potential targets in the respiratory chain of Mycrobacterium tuberculosis.Our emphasis is on the optimization strategy of QcrB inhibitors and the challenges of developing QcrB inhibitors as antituberculosis drugs due to the alternate bd-type oxidase oxidative compensation pathway are discussed.     

Structural and magnetic properties of Si1−xGex thin films implanted with Fe ions

A series of Si_1?xGe_x (x = 1, 0.848, 0.591, 0.382, 0.209, 0.064, 0) thin films prepared by ion beam sputtering were implanted with Fe ions to different doses using the metal vapor vacuum arc technique. X-ray absorption fine structure (XAFS) was used to characterize the local microstructure around the Fe atoms in Fe-doped Si_1?xGe_x samples. Structural analysis showed that for annealed samples of Ge-rich thin films (including pure Ge) implanted with low doses of Fe ions, almost all the Fe ions substituted at Ge sites. However, an anti-ferromagnetic Fe₆Ge₅ impurity phase existed in the annealed samples implanted with high doses of Fe. It was also found that the solubility of Fe ions was highest in pure Ge films and that with increasing Si concentration, the solubility decreased. Magnetic analysis showed that for the as-implanted and annealed samples of Ge-rich thin films implanted with Fe ions, room-temperature ferromagnetism was strongest in the pure Ge series of samples and that as the Ge concentration decreased, the ferromagnetism at room temperature weakened. In addition, annealing could increase the number of Fe ions at substitution sites, which resulted in the observed increase in the saturated magnetization after annealing. Experiment and theoretical analysis showed that the ferromagnetism of Fe-doped Ge-rich Si_1?xGe_x thin films samples originated from the s, p–d exchange interactions between the Si_1?xGe_x matrix and those Fe ions which substituted at Ge sites and that the ferromagnetism was mediated by carriers.     

The effect of interface hopping on inelastic scattering of oppositely charged polarons in polymers

The inelastic scattering of oppositely charge polarons in polymer heterojunctions is believed to be of fundamental importance for the light-emitting and transport properties of conjugated polymers. Based on the tight-binding SSH model, and by using a nonadiabatic molecular dynamic method, we investigate the effects of interface hopping on inelastic scattering of oppositely charged polarons in a polymer heterojunction. It is found that the scattering processes of the charge and lattice defect depend sensitively on the hopping integrals at the polymer/polymer interface when the interface potential barrier and applied electric field strength are constant. In particular, at an intermediate electric field, when the interface hopping integral of the polymer/polymer heterojunction material is increased beyond a critical value, two polarons can combine to become a lattice deformation in one of the two polymer chains, with the electron and the hole bound together, i.e., a self-trapped polaron-exciton. The yield of excitons then increases to a peak value. These results show that interface hopping is of fundamental importance and facilitates the formation of polaron-excitons.     

一种混合物体系荧光分析消除干扰的新方法

荧光分析法在测量混合物体系时,有些组分的最大激发峰相距较近,彼此之间会因存在干扰而得不着准确的荧光光谱。以中药苦参沸水浸取液为例,介绍了混合物体系中消除干扰的一种新方法。首先通过扫描苦参水浸液的荧光光谱,发现其中一种组分B对另一种组分A有明显干扰;然后通过几何作图法在组分B激发光谱中找到具有与组分A最大激发波长处同样荧光强度(也就是与在该点等高的位置处)的波长,以该波长作为激发波长扫描得到组分B在该波长处激发而得到的发射光谱;最后以受干扰的组分A的发射光谱减去该发射光谱即得到纯组分A的发射光谱。该方法使得在无法得到组分A和B的纯品时,对二者进行单独的荧光分析成为了可能。     

Ti/Pr0.7Ca0.3MnO3/La0.67Sr0.33MnO3/Pt异质结电致电阻效应的改善

采用脉冲激光沉积技术制备了Ti/Pr_0.7Ca_0.3MnO₃/Pt和Ti/Pr_0.7Ca_0.3MnO₃/La_0.67Sr_0.33MnO₃/Pt异质结并研究了La_0.67Sr_0.33MnO₃功能插层对异质结电致电阻特性的影响. 实验结果表明La_0.67Sr_0.33MnO₃功能层的引入有效提高了器件的电阻转变特性,尤其是电阻转变率和疲劳性得到了极大的改善. 对La_0.67Sr_0.33MnO₃插层改善电致电阻转变特性的机理进行了定性的分析. 关键词： 电致电阻效应 电阻转变比率 疲劳特性