Enantioselective Alternating Copolymerization of Propylene with Carbon Monoxide Using Cationic Palladium-Chiral Diphosphine Catalyst

Alternating copolymerization of (-olefins with carbon monoxide (CO) catalyzed by cationic palladium-chiral ligand complexes is of great interest due to the potential use of the resulting polymer as a new material1. Recently, enantioselective alternating copolymerization of CO with styrene has been reported by us using PdCl_2-CuCl2-chiral phosphine catalyst2. Here, we first report enantioselective alternating copolymerization of CO with propylene (P) using [(DDPPI)Pd(CH3CN)4](BF4)2 as …     

Reduction of Elemental Selenium by Samarium Diiodide: the Synthesis of Dithiodiselenides and Dithioselenides

Selenium is an essential element in living organism. It is reported that the selenosulfides have been transported in vivo in glutathione or coenzyme-A1. It is also discovered in low concentration in garlic2. In organic synthesis, selenosulfides are useful intermediates3. Several methods for the formation of sulfur-selenium bond have been reported. For example, the compounds including S-Se bond were prepared by chloroamination of thiols and selenols4; by heating the selenocyanate with thiols5…     

Preparation and Properties of Oxidized Graphite Anode Doped with Metal Ion for Lithium Ion Batteries

During the past years, there have been a lot of interests in the research of carbonaceous material as anode in lithium ion batteries1-3. Among them, natural graphite seems to be the most promising candidate for anode in lithium-ion batteries in terms of economy. Figure 1 The effect of Different Contents Figure 2 The Effect of Reacting Timeof Mixed Acid on Interlayer Distance On Interlayer DistanceHowever the raw natural graphite cannot be used for commercial purposes, because during proc…     

Synthesis and Structure of an Interlock Network Frame of Cobalt(Ⅱ) Coordination Polymer {[Co(azpy)_2(NCS)_2]·1/4EtOH·1/2H_2O}_n (azpy=4,4′-Azobispyridine)

A compound {[Co(azpy)_2(NCS)_2]·1/4EtOH·1/2H_2O}_n(1), where azpy=4,4'-azobispyridine, was synthesized and characterized by means of IR, TGA-DTA, magnetic susceptibility and X-ray single crystal diffraction. It consists of two independent sets of fully interlocked two-dimensional networks with the dihedral angle 61.7°, organized in parallel stacks of the sheets which are made of edge-shared [Co(Ⅱ)]_4 squares separated by 0. 9062nm, and defined size rhombic channels. The thermal gravimetric analysis indicates that the framework is stable up to 198℃. The variable-temperature magnetic susceptibility measurements indicated that there is a weak antiferromagnetic interaction between the cobalt(Ⅰ) ions in the complex (1).     

Effects of the Specific Area and the Thermal Stability of a Polymer on the Catalytic Activities of Polymer Immobilized Co-Pd Catalysts by SAMI

Co-Pd bimetallic catalysts immobilized with four kinds of resins with different specific areas were prepared by means of the solvated metal atom impregnation (SMAI) method. The results of the XRD and the magnetic measurement showed that as the specific area of the resin increased, the particle sizes of Co and Pd on the catalysts with the same metal content decreased, so the catalytic activity of the catalysts for the hydrogenation of diacetone alcohol as well as the reduction of oxygen on the fuel cell electrode increased. Below 140 , the conversion of diacetone alcohol increased as the reaction temperature increased, and above 140 , the conversion decreased because of the rupture of the resin.     

Ultrafast spectroscopy studies on the mechanism of electron transfer and energy conversion in the isolated pseudo ginseng, water hyacinth and spinach chloroplasts

The spectroscopy characteristics and the fluorescence lifetime for the chloroplasts isolated from the pseudo ginseng, water hyacinth and spinach plant leaves have been studied by absorption spectra, low temperature steady-state fluorescence spectroscopy and single photon counting measurement under the same conditions and by the same methods. The similarity of the absorption spectra for the chloroplasts at room temperature suggests that different plants can efficiently absorb light of the same wavelength. The fluorescence decays in PS II measured at the natural QA state for the chloroplasts have been fitted by a three-exponential kinetic model. The three fluorescence lifetimes are 30, 274 and 805 ps for the pseudo ginseng chloroplast; 138, 521 and 1494 ps for the water hyacinth chloroplast; 197, 465 and 1459 ps for the spinach chloroplast, respectively. The slow lifetime fluorescence component is assigned to a collection of associated light harvesting Chl a/b proteins, the fast lifetime component to the react     

5-氟尿嘧啶卟啉化合物的合成和光谱性质

首次合成并用元素分析、红外光谱、核磁和质谱等表征了6种新的5 氟尿嘧啶卟啉化合物. 对其紫外吸收、荧光性质和荧光寿命进行了研究,并与未修饰卟啉化合物光谱性质进行了比较. 5 氟尿嘧啶卟啉化合物荧光寿命为7 ns,受环境取代基和溶剂的影响较小.     

对基于质点速度测量的拉格朗日分析法的进一步探讨

针对以往基于质点速度波形测量使用拉格朗日分析法反推材料动态力学性能时,需作某种简化假定或者必须同时实测应力边界,而在实验过程中的边界应力数据在某些情况下测不到或测不准的状况.因此基于路径线法和零初始条件,提出了一种改进的拉格朗日分析法,新方法可不涉及边界应力,直接反推出材料高应变率下的动态应力应变曲线.并且运用该方法对有机玻璃材料的动态性能进行了数值模拟研究分析,其结果与运用特征线法求得到的数据非常吻合,从而证实了该方法的可靠性和有效性.     

基于UG的STEP运动仿真函数对运动时间的控制分析

利用UG自带的STEP运动仿真函数可控制模型驱动的运动时间段,从而获得从动件在不同时间段运动变化规律的特点,分析了UG仿真模块中的运动控制函数,提出一种将运动函数模型转化为UG仿真模块内的STEP运动控制函数,以方便设计者更好地掌握机构的运动仿真变化规律.还阐述了在UG仿真模块中,如何使用STEP运动函数来控制曲柄摇杆机构运动时间以及对双摇杆机构在运动极限范围内的运动仿真.     

Synthesis and Crystal Structure of Monochloridehepta(dimethyl sulfoxide)gadolinium(Ⅲ) di(tetraphenyl boron) Salt 〔Gd(dmso)_7Cl〕〔BPh_4〕_2

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