进样阀(I)

高效液相色谱进样阀（或进样器）的作用是将一定量的样品送入色谱仪。样品在流动相的带动下进入色谱柱系统完成分离过程。现代高效液相色谱仪对于进样阀的要求如下：（１）耐高压,因为高效液相色谱通常要在３５．０ＭＰａ或更高的压力下工作;（２）进样量精确;（３）进样重复性好;（４）方便、适用,且可根据需要选择不同的进样量;（５）价格低廉;（６）保证在色谱柱中心进样,操作时不产生流量或压力波动。到目前为止,液相色谱进样阀共有３种形式：１．手动注射进样器;２．手动进样阀;３．自动进样器。从原理上讲,自动进样器是在…     

Small Gold(I) and Gold(I)–Silver(I) Clusters by C−Si Auration

Auration of o-trimethylsilyl arylphosphines leads to the formation of gold and gold–silver clusters with ortho-metalated phosphines displaying 3c–2e Au−C−M bonds (M=Au/Ag). Hexagold clusters [Au₆L₄](X)₂ are obtained by reaction of (L−TMS)AuCl with AgX, whereas reaction with AgX and Ag₂O leads to gold–silver clusters [Au₄Ag₂L₄](X)₂. Oxo-trigold(I) species [Au₃O]⁺ were identified as the intermediates in the formation of the silver-doped clusters. Other [Au₅], [Au₄Ag], and [Au₁₂Ag₄] clusters were also obtained. Clusters containing PAu−Au−AuP structural motif display good catalytic activity in the activation of alkynes under homogeneous conditions.     

PHOTOCYCLOADDITION BETWEEN 8-METHOXYPSORALEN (8-MOP) AND OLEFINES (Ⅲ)

The photocycloadditions between 8-methoxypsoralen(8-MOP) and olefines have been in-vestigated. It gives a series of head-to-tail cycloadducts. From the reaction rates and cal-culated values of polarizability of olefines it indicates that reaction rates are dependent onthe polarizability of olefines. The stereochemistry of these products has been studied. Inview of these results it shows that the electron-deficient C_3-position of the triplet state of 8-MOP attacks the olefines electro-philically at first, then the reactions proceed to form pro-ducts via diradical mechanism.     

Lumineszierende Cu(I)-, Ag(I)- und Tl(I)-Komplexe mit N-Butyl-N′-benzolsulfonylthioharnstoff- Tetra- und hexamere (ML)x-Cluster

Zusammenfassung Das Säureanion von N-Butyl-N-benzolsulfonylthioharnstoff (BuBsT) bildet mit Cu(I) einen lumineszierenden hexameren und einen nicht lumineszierenden tetrameren Cluster (Cu(BuBsT))_x; x=6, 4. Röntgenstrukturanalysen belegen für x=6 eine verzerrt oktaedrische und für x=4 eine verzerrt tetraedrische Anordnung der Cu-Atome. Die Liganden beider Cluster sind über den Thioharnstoff-Schwefel und den Sulfonamid-Stickstoff mit den Cu-Atomen verknüpft (S,N-Koordination). Jeweils ein Sulfonyl-Sauerstoffatom pro Ligand bildet eine intramolekulare Wasserstoffbrücke zu der NHC₄H₉-Gruppe der gleichen Ligandeinheit aus. Ag(BuBsT) tritt in Form von drei lumineszierenden Modifikationen auf, von denen eine (Ag(BuBsT)-II) hexamer ist (isotyp mit (Cu(BuBsT))₆). Tl(BuBsT) liegt in CHCl₃-Lösung überwiegend als Dimer vor.

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Luminescent Cu(I)-, Ag(I)- and TI(I)-complexes with N-Butyl-N-benzenesulfonylthiourea-tetramer and hexamer (ML)_x-clusters

Summary The acid anion of N-butyl-N-benzenesulfonylthiourea (BuBsT) forms numerous 1/1 complexes with the univalent ions Cu(I), Ag(I) and Tl(I). The crystal structures of two different copper(I) clusters (Cu(BuBsT))_x, (x=6, 4) are discussed. The hexamer containing a distorted Cu₆ octahedron is luminescent, while the analogous tetramer containing a distorted Cu₄ tetrahedron is not. The copper atoms of both clusters form coordinate linkages with the sulfonamide nitrogen and the thiourea sulphur of the ligands (S,N-coordination). One sulfonyl oxygen per ligand is bound to the NHC₄H₉ group of the same ligand through a hydrogen bond. Ag(BuBsT) forms three different luminescent modifications. One of them (Ag(BuBsT)-II) is isotype to (Cu(BuBsT))₆ and therefore hexamer, too. Tl(BuBsT) mainly forms dimers in CHCl₃ solution.

     

Luminescence of cesium dicyanoaurate(I). Evidence for extended Au(I)Au(I) interactions in two dimensions

The luminescence of microcrystalline samples of Cs[Au(CN)₂] is reported and ascribed to planar AuAu interactions. Low-temperature measurements from 1.6 to 100 K of the luminescence decay rate of Cs[Au(CN)₂] for the band centered at 458 nm reveal the presence of at least two emitting levels separated by 46 cm⁻¹. A simple orbital model is proposed to account for the luminescence, and spin—orbit coupling is invoked to explain the splitting of the two lowest states. The analogies and differences between this luminescence and that observed for salts of Pt(CN)₄²⁻ are briefly discussed.     

New Chiral Substituted 8-Quinolinyl-oxazolines as Ligands for Copper(I)-catalyzed Asymmetric Cyclopropanation

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Natriummetaphosphat (I) in Metaphosphors?ure (II)

Ohne Zusammenfassung     

金属碳笼化学反应的理论研究(Ⅰ)──Ti_8C_(12)~++CH_3I→Ti_8C_(12)~+──I+CH_3·的从头算研究

用量子化学从头计算方法对反应Ti8C12+＋CH3I→Ti8C12+-I＋CH3·进行了理论研究，对Ti8C12+只能与一个卤素原子（1）结合的实验事实给予了合理的理论解释．     

微量元素与阿尔茨海默病(8)

阿尔茨海默病(AD)是目前老年人最为关注的重要健康问题。中国55岁以上人群的AD患病率已超过2.0%,患病总人数在600万以上,中国已成为全球痴呆人数最多、速度增加最快的国家。至今人们对该病病因及其机制的了解仍然有限,亦无有效的药物可以阻止和治疗该病的发生和发展。该文在前人研究的基础上,全面总结并提出了该病病理的微量元素稳态障碍假设,详尽阐述了新学说的三个组成部分及四个方面的实践证据。     

Au(I)、Ag(I)、Cu(I)氰合离子在大孔强碱性阴离子交换树脂中的传质研究

测定了不同温度下Au(Ⅰ)、Ag(Ⅰ)、Cu(Ⅰ)氰合离子分别在大孔强碱性苯乙烯系CN、Cl、OH型离子交换树脂中的内扩散系数和扩散活化能。从结果得出,氰合离子在树脂相中扩散传质异常缓慢并非由于过高的活化能,而可能是由于过低的活化熵所致。     

Ce(C_8H_8)_2和Ce(C_8H_8)_2~-的化学键性质

结合改进的重叠模型Xa-SW法和Ziegler过渡态法,通过将中心原子与配体的作用选成离子聚集、中心原子只有s和p轨道参与成键、中心原子只有d轨道参与成键、中心原子只有f轨道参与成键、中心原子的s、p、d和f轨道同时参与成键5种类型,从能量角度分析了Ce(C_8H_8)_2和Ce(C_8H_8)~-_2的化学键性质。