氯化原卟啉Ⅸ二甲酯合钴(Ⅲ)的合成及其与咪唑反应动力学的研究

从原卟啉Ⅸ（ＰＰⅨ）出发合成氯化原卟啉Ⅸ二甲酯合钴（Ⅲ），分别用元素分析，ＵＶ光谱和ＩＲ光谱表征。２９８Ｋ时，测定氯化原化原卟啉Ⅸ二甲酯合钴（Ⅲ）与咪唑反应在丙酮或二氯甲烷剂中的表观速率常数ｋｏｂ３，结果表明反应的决速步是单分子咪唑中间体Ｃｏ（Ⅲ）ＰＰⅨＤＭＥ（ＲＩｍ）Ｃｌ中氯的离解，总反应速率方程对咪唑是一级反应；氯离解的速率常数ｋ１依赖于溶剂与氯形成氢键的能力，即“远位咪唑氢键效应”；当咪唑中     

微波辐射法合成α-萘甲醚的研究

用微波辐射法合成α－萘甲醚，考察了不同条件对产率的影响，此法反应时间短，产率可达75％。     

Green and red fluorescent proteins: photo- and thermally induced dynamics probed by site-selective spectroscopy and hole burning.

The cloning and expression of autofluorescent proteins in living matter, combined with modern imaging techniques, have thoroughly changed the world of bioscience. In particular, such proteins are widely used as genetically encoded labels to track the movement of proteins as reporters of cellular signals and to study protein-protein interactions by fluorescence resonance energy transfer (FRET). Their optical properties, however, are complex and it is important to understand these for the correct interpretation of imaging data and for the design of new fluorescent mutants. In this Minireview we start with a short survey of the field and then focus on the photo- and thermally induced dynamics of green and red fluorescent proteins. In particular, we show how fluorescence line narrowing and high-resolution spectral hole burning at low temperatures can be used to unravel the photophysics and photochemistry and shed light on the intricate electronic structure of these proteins.     

High-Yield Syntheses of Tetra-O-benzyl-α-D-glucopyranosyl bromide and Tetra-O-pivaloyl-α-D-glucopyranosyl bromide and their Advantage in the Koenigs-Knorr Reaction

Several improved approaches for the preparation of tetra-O-benzyl-α-D-glucopyranosyl bromide and tetra-O-pivaloyl-α-D-glucopyranosyl bromide are discussed. The importance of these compounds, which are useful glycosyl donors, was demonstrated by successful preparation of cholesteryl glucopyranosides in an almost neutral medium without the formation of orthoesters. In addition, accurate ¹H and ¹³C NMR resonance assignments of the synthesized cholesteryl glycosides were performed by 2D NMR spectroscopy.     

Indium (III) Tribromide : An Excellent Catalyst for Biginelli Reaction

A highly efficient catalyst indium (III) tribromide is used to synthesize 5-alkoxy- carbonyl-4-hydrocarbyl-3,4-dihydropyrimidin-2(1H)-ones by a three-component coupling of β-keto ester, aldehydes and urea through improved Biginelli reaction.     

Atomic emission and atomic absorption spectrometric analysis of high-purity powders for the production of ceramics

Summary Direct analysis methods and multistage combined analytical procedures for the determination of impurities at the g/g level and the upper ng/g level in high-purity powders of Al₂O₃, AlN, Si₃N₄ and SiC are described. Results obtained with a novel direct slurry-atomization technique using a Babington nebulizer and inductively coupled plasma optical emission spectrometry (ICP-OES) are presented. A comparison of analysis results of combined analytical procedures including wet chemical decomposition and determinations with graphite furnace atomic absorption spectrometry (ETAAS) or ICP-OES with those of slurry-atomization ICP-OES show the capabilities of this technique for routine analysis in production control. Detection limits for Al, B, Ca, Co, Cu, Fe, Mg, Mn, Si, Ti, W, V, and Zn in the matrices mentioned are between 0.03 and 2.5 g/g. For elemental concentrations 10 g/g relative standard deviations of the measurements are generally below 10%. The technique is shown to be a powerful tool for trace determinations in powder samples. This is shown by its use for analysis of a series of the ceramic powders mentioned and comparative results of other direct techniques such as total reflection X-ray fluorescence spectrometry and instrumental neutron activation analysis.

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OES und AAS von hochreinen Pulvern für die Keramikherstellung

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Herrn Prof. Dr. G. Tölg zum 60. Geburtstag von seinen Mitarbeitern gewidmet     

Chromatographic molecular recognition for catechol-related compounds using thiacalix[4]arene as an effective selector

Thiacalix[4]arene (5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrahydroxy-2,8,14,20-tetrathiacalix[4]arene) is an amphiphilic molecule comprising four p-tert-butylphenol-like groups ortho-linked by single sulfur atoms. This molecule has a high electron density area owing to the close proximity of the hydroxyl groups and sulfur atoms. We studied the applicability of this interesting compound as a selector for high-performance liquid chromatography (HPLC) thereby presumably exploiting this feature. Firstly, uniformly sized polymer particles were prepared by using a multi-step swelling and polymerization method with ethylene glycol dimethacrylate (EDMA) as a cross-linker. Methacrylic acid (MAA) was introduced onto the surface of the resulting polymer particles through a new modification method. Thiacalix[4]arene was chemically bonded through the MAA group by using 1,4-dibromobutane as a spacer to reduce steric hindrance around the MAA and the polymer particle itself. The performance of the prepared polymer-based thiacalix[4]arene-modified stationary phase was evaluated with HPLC. Specific chromatographic retention behavior was observed for catechol relative to positional isomers of xylene, cresol, and benzene-diol. Catecholamine and catechol showed specific chromatographic retention behavior.     

DNA Hydrolysis by Homo- and Heteronuclear Cu(II)–Ni(II) Complexes of Two Diester-type Ligands

Nucleolytic activities of novel mononuclear Cu(II), homo- and heterodinuclear Cu(II)–Ni(II) complexes with two diester-type ligands were investigated on pCYTEXP by neutral agarose gel electrophoresis. The analyses of the cleavage products obtained electrophoretically indicate that the examined complexes induce very similar conformational changes on supercoiled DNA by converting supercoiled form to nicked form. At concentrations greater than 100M, the complexes possessed effective nucleolytic activities for 10min of incubation time. However, their nucleolytic activities did not increase significantly with longer periods of incubation. The pH-nucleolytic activity profiles of the complexes differed significantly. Metal complex induced DNA cleavage was also tested for inhibition by various radical scavengers. It could be proposed from the data that diffusible intermediate oxidants are not involved in these reactions or they are not necessary for DNA cleavage since none of antioxidants inhibited DNA cleaving activities of the complexes.     

Separation of biomolecules by μ-high-performance anion-exchange chromatography using a tentacle-like stationary phase

A variety of biomolecules and their variants, which have previously been problematic to separate, have been analysed using a novel anion-exchange resin based on a non-porous polystyrene polymeric support with a hydrophilic coating and grafted tentacular quaternary ammonium functional groups. The hydrophilic coating results in minimal interaction between the support and the biomolecule, while the highly flexible tentacular-like anion-exchange groups increase the ionic interaction potential and act as an umbrella to hold the proteins away from the surface. Because of the removal of silanophilic interactions, minimisation of hydrophobic interactions, and the highly flexible nature of the tentacle-like ion exchangers, ionic interactions can therefore dominate the separation. As such this phase is highly suited to the separation of highly charged biomolecules and their variants. This polymeric strong anion-exchange (SAX) support was packed into a fused-silica capillary column and, using a salt concentration gradient, various recombinant proteins were analysed by -HPLC resulting in baseline resolution.Awarded a poster prize on the occasion of the Euranalysis XIII conference, Salamanca, Spain, 5–10 September 2004