Ab Initio Calculations for FO3, FO 3 + , and FO 3 - Complexes Formed by Fluorine with Ozone

Complexes formed by fluorine with ozone, featuring neutral, positive, and negative species, as well as the decomposition reactions of the complexes are investigated with quantum chemical calculations, using the 6-311G* and the 6-311+G* basis sets, with the Moller-Plesset method. The most stable structures of the complexes are identified and the energies of the reactions of the complexes' formation and decomposition are obtained.     

Principle and applications of a floating energy analyser

We describe a new type of energy analyser suitable for the use in plasmas having no external potential reference like ICPs and microwave discharges. It can be used to determine the ion distribution function (IDF) at a negatively biased surface and the high energy tail of the plasma electron distribution function (EDF). The EDF is measured without distortions by ion currents. This analyser was tested in a dc glow discharge and its results compared to measurements with Langmuir probes and a analyser with grounded reference. Some preliminary measurements were also performed in a rf parallel plate discharge. Dedicated to Prof. Jan Janča on the occasion of his 60th birthday, in remembrance of a fruitful and friendly European co-operation. This work was supported by the Deutsche Forschungsgemeinschaft Bonn by Sonderforschungsbereich 191 and by the Directorate-General XII Science, Research and Development of European Commission, under Grant ERBCIPACT924034.     

Benzofuro[2,3-d]pyridazines IV. Etude de la chloro-4 benzofuropyridazine

[1] Benzofuro[2,3-d] pyridazone was synthesized by three methods namely8: catalytic dehalogenation of the 4-chlorobenzofuro [2,3-d] pyridazone; removal of the hydrazono group of 4-hydrazinobenzofuro [2,3-d] pyridazine and desulphurization of benzofuro [2,3-d] pyridazine and desulphurization of benzofuro [2,3-d] pyridazine-4(3H) thione. The 4-substituted derivatives were obtained by nucleophilic attack of the 4-chlorobenzofuro[2,3-d] pyridazine. Tetrazolo[1,5-b]- and s-triazolo-[1,2-b] benzofuro [2,3-d] pyridazones. The structural assignment of the benzofuro[2,3-d]pyridazones was made by the Noe effect.     

Solvation energies of planar and pseudo-planar molecules

The Born equation for solute-solvent interaction is generalized to planar and pseudo-planar molecules. The solvation energies thus obtained are compared to experimental values and the agreement is satisfactory.     

Chromatographie d'élution des aminoacides et de leurs dérivés sur colonne d'échangeurs d'ions à trame hydrophile

Sommaire Le comportement chromatographique des dansylaminoacides hydrosolubles (acide dansylcysteique, -monodansylarginine, -monodansylhistidine, -monodansyllysine, -monodansyllysine), des aminoacides correspondants, et du dansylacide sur colonne d'échangeur de cation à trame hydrophile (Phospho-cellulose, Sulfoéthyl-dextrane réticulé) est rappelé. Les monodansyldérivés de l'arginine, de l'histidine, de la lysine peuvent être isolés à l'état pur de leur milieu de formation par un procédé chromatographique employant ces échangeurs de cations. L'acide dansylcysteique, non retenu (comme le dansylacide) par ces échangeurs de cations, peut être séparé du dansyl-acide et de l'acide cysteique, par chromatographie sur colonne de Diéthylaminoéthyldextrane réticulé. Un procédé chromatographique similaire permet de séparer les deux dérivés monodansylés de la lysine.

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Elution chromatography of aminoacids and their derivatives on an ion exchange column with hydrophilic cross-linkagePart 2: Behaviour of water-soluble dansylamino acids on an ion exchange column of cross-linked DEAE dextrane

Summary The chromatographic behaviour of water soluble dansylamino acids (dansylcysteic acid, -monodansyl arginine, -monodansyl histidine, -monodansyl lysine, -monodansyl lysine), of the corresponding amino-acids, and of dansyl acid on a cation exchange column with hydrophilc crosslinks (Phosphocellulose, cross-linked Sulfoethyl dextrane) is reported. The monodansyl derivatives of arginine, histidine, and lysine can be isolated in pure form from the medium in which they have been formed, by means of a chromatographic procedure using these cation exchangers. Dansylcysteic acid. Which is not retained (like dansyl acid) by these cation exchachangers, can be separated from dansyl acid and from cysteic acid by chromatography on a column of cross-linked diethyl aminoethyl dextrane. A similar chromatographic process permits the separation of the two monodansyl derivatives of lysine.

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Elutions-Chromatographie von Aminosäuren und ihren Derivaten auf einer Ionenaustauscher-Säule mit hydrophiler Füllung2. Teil: Verhalten der hydro-säurelöslichen Dansylaminosäuren auf einer Ionenaustauscher-Säule mit vernetztem DEAE-Dextran

Zusammenfassung Es wird an das chromatographische Verhalten der hydrolöslichen Dansylaminosäuren (Dansyl-Cysteinsäure, -Monodansyl-arginin, -Monodansyl-histidin, -Monodansyl-lysin, -Monodansyl-lysin) sowie der entsprechenden Aminosäuren und von Dansylsäure auf einer Kationenaustauscher-Säule mit hydrophiler Füllung (Phospho-cellulose, vernetztes Sulfoäthyldextran) erinnert. Durch ein chromatographisches Verfahren mit derartigen Kationen-Austauschern lassen sich die Monodansylderivate von Arginin, Histidin und Lysin im Reinzustand aus ihrem Entstehungs-Medium isolieren. Die nicht (wie die Dansylsäure) von diesen Kationenaustauschern zurückgehaltene Dansylcysteinsäure kann durch Chromatographie auf einer Säule mit vernetztem Diäthylaminoäthyldextran von der Dansylsäure und der Cysteinsäure getrennt werden. Durch ein ähnliches chromatographisches Verfahren lassen sich die beiden Monodansylderivate von Lysin trennen.

     

Phosphorus-containing dendrimers bearing galactosylceramide analogs: self-assembly properties

We report the synthesis and the supramolecular auto-assembly of catanionic phosphorus-containing dendrimers mimicking multisite analogs of galactosylceramide.     

Investigation of the Interactions of Polyvinylpyrrolidone with Mixtures of Anionic and Nonionic Surfactants or Anionic and Zwitterionic Surfactants by Pulsed Field Gradient NMR

The interaction of polyvinylpyrrolidone (PVP) with an anionic surfactant (sodium dodecyl sulfate, SDS), a nonionic surfactant (pentaethylene glycol monodecyl ether, C(10)E(5)), and a zwitterionic surfactant (lauryl amido propyl betaine, LAPB) has been investigated by means of pulsed gradient spin-echo NMR (FT-PGSE NMR), allowing self-diffusion coefficients to be determined. The results confirm the strong interaction prevailing in the PVP/SDS system, whereas no association has been observed in the PVP/C(10)E(5) and PVP/LAPB systems. Mixing PVP with two surfactants, namely SDS and C(10)E(5) or SDS and LAPB, results in the formation of ternary aggregates between the polymer and the mixed micelles. Copyright 2001 Academic Press.