Synthesis of 1‐Methyl‐3‐aryl‐substituted Titanocene and Zirconocene Dichlorides and Crystal Structure of Bis[η5‐1‐methyl‐3‐(α, α‐dimethylbenzyl) cyclopentadienyl] titanium Dichloride

The syntheses of a series of l‐methyl‐3‐aryl‐substituted titanocene and zirconocene dichlorides are reported. These complexes are synthesized by the reaction of 2‐ and 3‐methyl‐6, 6‐dimethylfulvenes (1:4) with aryllithium, followed by the reaction with TiCl₄·2THF, ZrCl₄ and (CpTiCl₂)₂O respectively, to give complexes 1–5. The complex [η⁵‐1‐methyl‐3‐(α, α‐dimethylbenzyl) cyclopentadienyl] titanium dichloride has been studied by X‐ray diffraction. The red crystal of this complex is monoclinic, space group P2_t/C with unit cell parameters: a =6.973(6) × 10^?1 nm, b =36.91(2) × 10^?1 nm, c = 10.063(4) × 10^?1 nm, α=β= γ = 93.35(5)°, V = 2584(5) × 10^?3 nm³ and Z = 4. Refinement for 1004 observed reflections gives the final R of 0.088. There are four independent molecules per unit cell.     

Asymmetric Pauson-Khand-type reaction mediated by Rh(I) catalyst at ambient temperature

An efficient asymmetric PKR mediated by Rh(I) catalyst at ambient temperature was developed. The reaction utilizing a Rh(I) catalyst bearing a (R)-3,5-diMeC4H4-BINAP ligand at 18-20 degrees C under a reduced partial pressure of CO (0.1 atm) provided PKR products in high chemical yield as well as high enantioselectivity.     

catena‐Poly­[[tetra­aqua­iron(II)]‐μ‐succinato‐κ2O:O′]

The title complex, {[Fe(C₄H₄O₄)(H₂O)₄]}_n, is an infinite poly­meric compound bridged by the succinate dianion. Two carboxyl­ate groups coordinate in a monodentate manner to the Fe^II atom, in a trans fashion, with an O—Fe—O bond angle of 175.72 (6)° and Fe—O distances of 2.0886 (14) and 2.1008 (15) Å. One of the uncoordinated carboxyl­ate O atom forms an intramolecular hydrogen bond with a coordinated water mol­ecule. Extensive hydrogen bonding between parallel poly­meric complex chains results in a three‐dimensional supramolecular structure.     

Vanishing Shear Viscosity Limit in the Magnetohydrodynamic Equations

We study an initial boundary value problem for the equations of plane magnetohydrodynamic compressible flows, and prove that as the shear viscosity goes to zero, global weak solutions converge to a solution of the original equations with zero shear viscosity. As a by-product, this paper improves the related results obtained by Frid and Shelukhin for the case when the magnetic effect is neglected. Supported by NSFC (Grant No. 10301014, 10225105) and the National Basic Research Program (Grant No. 2005CB321700) of China.     

一维三元光子晶体微腔中模式竞争特性的研究

用输矩阵的方法研究了一维三元光子晶体带增益介质微腔的传输特性,结果显示透射谱有模式竞争的特性.发现透射主峰的中心波长和ZnO增益介质层厚度互相匹配.在其他参数合适的情况下,改变ZnO增益介质层厚度,透射主峰的中心波长也相应改变.另外,增大光子晶体介质层数目或是增大泵浦光强度,模式竞争现象更加明显.     

22Na(p,γ)23Mg反应的实验研究

讨论了目前有关²²Na(p,γ)²³Mg反应的实验研究工作,结合兰州放射性束流线上的放射性束流²³Al的β⁺延发质子衰变实验的测量结果,给出了²³Al延发衰变的质子能谱,并比较了近期实验给出的相关能级的自旋、宇称值,正是由于这种自旋、宇称和能级部分宽度的不确定性,导致了反应率计算的不确定性.计算了同位旋相似态的共振强度.对于测量到的新的延发衰变能级E_d=8.916MeV,由于没有相应的能级宽度值,实验仅给出其相对共振强度值.     

The limiting absorption principle for the two-dimensional inhomogeneous anisotropic elasticity system

In this work we establish the limiting absorption principle for the two-dimensional steady-state elasticity system in an inhomogeneous aniso- tropic medium. We then use the limiting absorption principle to prove the existence of a radiation solution to the exterior Dirichlet or Neumann boundary value problems for such a system. In order to define the radiation solution, we need to impose certain appropriate radiation conditions at infinity. It should be remarked that even though in this paper we assume that the medium is homogeneous outside of a large domain, it still preserves anisotropy. Thus the classical Kupradze's radiation conditions for the isotropic system are not suitable in our problem and new radiation conditions are required. The uniqueness of the radiation solution plays a key role in establishing the limiting absorption principle. To prove the uniqueness of the radiation solution, we make use of the unique continuation property, which was recently obtained by the authors. The study of this work is motivated by related inverse problems in the anisotropic elasticity system. The existence and uniqueness of the radiation solution are fundamental questions in the investigation of inverse problems.

     

动态固相微萃取-气相色谱法测定环境空气中挥发性脂肪酸的研究

建立了动态固相微萃取-气相色谱(FID)测定环境空气中挥发性脂肪酸(VFAs)的分析方法,选择乙酸(AA)、丙酸(PA)、丁酸(BA)、异丁酸(iso-BA)、戊酸(VA)和异戊酸(iso-VA)6种代表性VFAs为研究对象,研制了动态萃取装置并建立了动态萃取机制。研究了固相微萃取材料、萃取时间、萃取温度、萃取流速、解析温度及时间对VFAs萃取效率的影响,在此基础上优化了气相色谱法检测条件。在优化条件下,6种脂肪酸的线性范围均达到4个数量级,相关系数均大于0.990。方法的检出限(S/N=3)为1.0~4.7μg/L,相对标准偏差(RSD,n=3)为1.1%~6.8%。与常规方法相比,该方法大大提高了检测范围和检测灵敏度,并成功用于环境空气中挥发性脂肪酸的分析检测。     

化学拆分的新方法研究

主要介绍了近年来发展起来的两种化学拆分新方法,包括拆分和组合拆分;并简要论述了化学拆分中的手性识别现象,以及化学拆分方法在手性药物制备中的应用。     

差示扫描量热法测定马来酸酐纯度

用差示扫描量热法（DSC）测定马来酸酐的纯度,测定条件为升温速率0．8℃／min,样品量2．6～2．8mg,氮气流速为40mL/min。纯度测定结果的相对标准偏差（RSD）为0．02％（n=5）。将DSC法、液相色谱法、药典法、滴定分析法对不同物质纯度的测定结果进行了比对,4种方法的测定结果基本一致。DSC法简便、快速、准确、重现性好,适合马来酸酐纯度的测定。