高效液相色谱检测Zn（Ⅱ）、Cd（Ⅱ）、Co（Ⅱ）、Pb（Ⅱ）、Ni（Ⅱ）、Cu（Ⅱ）、Hg（Ⅱ）

用双-(2-羟乙基)二硫代甲酸铵(HEDC)在反相液相色谱中作检测某些金属离子的衍生化试剂，HEDC的金属螯合物微溶于水，可直接水样注射于C18柱中进行检测，范围为0．006～10mg／L相对偏差1％～2％，检测波长254nm，金属汞的整合物在HPLC分析前进行浓缩富集检测限可低至0．06～25μg／L，相对偏差小于2％。     

Ternary surface complexes by theE(%)-pH curve method

A new method for the study of ternary surface complexes at liquid-solid interface, theE(%) -pH curve method, was proposed. Four types ofE(%)-pH curves, namely, phenomenon of left-right shifts of S-shaped curve, V-shaped curve, monodirection shift curve and X-shaped curve, were discovered. Correspondingly, apart from type (I) ternary surface complex and type (II) ternary surface complex , a new type of ternary surface complex was discovered. Project supported by the National Natural Science Foundation of China and the Fund of Doctoral Degree’s Spot.     

碱性溶液中金电极上氧还原中间物研究

应用改进了的旋转全电极上的电势阶跃计时库仑法,分别测定了不同电极电势下氧还原过程中电极吸附中间物和溶解中间物氧化所需的电量,实验证明,在此过程中电极上确有吸附中间物存在,而且是电极电势的函数,但其分子属性尚需进一步鉴别。     

Chelate mit Diimin- und Thiol-Struktur: Analytische Anwendung der Di-(4-substituierten)-thiosemicarbazone von 1,2- und 1,3-Diketonen

Zusammenfassung In der Gruppe der vierzähnigen Liganden mit Diimin- und Thiolstruktur bilden die Bisthiosemicarbazone von 1,2- und 1,3-Diketonen mit 4-substituierten Thiosemicarbaziden intensiv gefärbte Metallchelate, die für extraktionsphotometrische Bestimmungen in der Spurenanalyse verwendet werden können. Die molaren Extinktionskoeffizienten liegen im Bereich 5000–16000. Die leichte Zugänglichkeit von 4-substituierten Thiosemicarbaziden über die Reaktion von Isothiocyanaten mit Hydrazin bietet eine große Auswahl von Reagentien, besonders für die Flüssig-Chromatographie zur Trennung von komplexen Chelatgemischen.Die Arbeit wurde aus den Mitteln der Deutschen Forschungsgemeinschaft Bonn-Bad Godesberg gefördert.     

A density functional study on magnetic exchange interaction between Mn(II) ion and nitronyl nitroxide radical in <Emphasis Type="Italic">trans</Emphasis>-and <Emphasis Type="Italic">cis</Emphasis>-metal-radical complexes

The magneto-structural correlation between a Mn(ll) ion, coordinated in an octahedral environment, and two nitronyl nitroxide radical ligands in trans- and cis-metal-radical complexes is investigated by the broken symmetry (BS) approach within density functional theory (DFT). The dependences of coupling constants J on three structural parameters: (i) bond angle θ (Mn-O-N (nitroxide)); (ii) rotating angle ψ, defined by the nitronyl nitroxide radical plane rotating around the axial Mn-O (nitroxide); (iii) bond distance R (Mn-O (nitroxide)) are directly calculated. Our calculations showed that both trans- and cis-Mn(ll)-radical complexes behave a stronger antiferromagnetic interaction, consistent with experiments. In view of molecular orbital theory, the direct exchanges, including σ-type and π-type exchanges, are responsible for the magnetic exchange pathways. There is a preferable linear correlation between the calculated coupling constants J and the overlap integral squares S b between the local magnetic orbitals at the various rotating angle ψ at the fixed bond angle θ and bond distance R, in both trans- and cis-Mn(ll)-radical complexes.     

Application of the essential work of fracture concept to nanostructured polymer materials

The first part of the paper deals with a critical discussion of the methodical basis of essential work of fracture (EWF) concept with respect to the specimen geometry (especially the notch depth) and application to polymers. In the second part, an in situ testing device, which combines a tensile testing machine with an optical strain-field measuring system, has successfully demonstrated possibility of characterization of fracture behaviour of polystyrene-polybutadiene block copolymers and block copolymer/homopolymer blends as examples of nanostructured polymer materials. It has been shown that knowledge of the time evolution of the strain field close to the crack tips leads to a simple verification of the basic precondition for the applicability of the EWF concept, the precondition “plastic zone coalescence-before-stable crack propagation”.     

Synthesis of β-ketoenamine donors having O, N, Se/Te donor functionalities and their reaction chemistry with Pd(II) and Pt(II) metal ions

Monoanionic tridentate ligands LH_a and LH_b containing ONSe and ONTe donor sequences and their Pd²⁺ and Pt²⁺ derivatives were synthesized and characterized. The formation of a five- and a six-membered ring around the central metal atom and associative phenomena in solutions provide extra stability to the metal complexes.     

Synthesis and polymerization of N-[N′-(α-methylbenzyl)aminocarbonyl-n-alkyl]maleimide

Two types of optically active N-[N′-(α-methylbenzyl)amino/carbonyl-n-alkyl]maleimides (MBAC) were synthesized from maleic anhydride, 6-amino-n-caproic acid (or 12-amino-n-dodecanoic acid), and (R)-(+)-α-methylbenzylamine. Radical homopolymerizations of MBAC were performed in several solvents at 60 and 110°C for 24 h to give optically active polymers. Radical copolymerizations of MBAC were performed with styrene (ST) and methyl methacrylate (MMA) in dioxane at 60°C. The monomer reactivity ratios and the Alfrey-Price Q-e values were determined. Chiroptical properties of the polymers and copolymers were investigated. © 1995 John Wiley & Sons, Inc.     

Cross-metathesis of vinyl aromatic heterocycles with 1-octene in the presence of a Schrock catalyst

Metathesis of 2-vinyl aromatic heterocycles such as furan, thiophene, pyrrole and pyridine in the presence of a molybdenum-based Schrock catalyst has been investigated from a synthetic point of view. The self-metathesis of 2-vinyl aromatic heterocycles was not successful. However, in cross-metathesis of thiophene, furan and styrene with 1-octene, the cross-metathesis product, heterodimer, was readily obtained selectively, together with only small amounts of the two corresponding self-metathesis products. The origin of the surprisingly high selectivity of heterodimer formation was elucidated through metallacyclobutane intermediate mechanism, observations of carbenes by in situ ¹H NMR, and reaction products.     

（Z）—3—丁烯基—4,5—二羟基苯酞的合成

（Ｚ）－３－丁烯基苯酞和它的衍生物广泛地存在于微形科植物，如当归、川芎等，这些植物有些是重要的中药材。（Ｚ）－３－丁烯基－４，５－二羟基苯酞是（Ｚ）－３－丁烯基苯酞的类似物；它对前列腺素Ｆ２α具有抑制作用。本文以３，４－二甲氧基苯甲醇（２）或价廉易得的胡椒醇（６）为起始原料，分别经四步反应顺利地合成了（Ｚ）－３－丁烯基－４，５羟基苯酞（１）。和一步是本方法的关键，即利用杂原子诱导的区域选择性的芳环