Unexpected Hofmann elimination in the benzophenone-(phenylthio)acetic tetrabutylammonium salt photoredox system

The triplet state of benzophenone was quenched by the tetrabutylammonium salt of (phenylthio)acetic acid in acetonitrile solutions. The quenching event, following laser flash photolysis, resulted in the formation of a transient ion pair consisting of the benzophenone radical anion and the tetrabutylammonium cation. Subsequently this ion pair decays with the quaternary ammonium cation undergoing a Hofmann elimination to form butane-1 and tributylamine, which were detected in steady-state irradiation. This appears to be the first report of an ion pair consisting of a benzophenone radical anion and an organic cation (nonradical), in addition to the first report of a photoinduced Hofmann elimination in quaternary ammonium ions.     

Key Word Index of Volume 38 – 2003

Other Index

Key Word Index of Volume 38 – 2003     

Continued fractions in local fields, II

The present paper is a continuation of an earlier work by the author. We propose some new definitions of -adic continued fractions. At the end of the paper we give numerical examples illustrating these definitions. It turns out that for every if then has a periodic continued fraction expansion. The same is not true in for some larger values of

     

A numerical model of multimode fiber PON frequency response

Frequency response of passive optical network (PON) based on multimode fibers is investigated. The network comprises fibers, connectors and splitters/couplers. It is shown that due to mode filtering at splitters, the frequency response is different for different network nodes in otherwise symmetrical network.     

The influence of some fuzzy implication operators on the accuracy of a fuzzy model-part II

The influence of fuzzy implication operators and the connective Also on the accuracy of a fuzzy model of a d.c. series motor is considered. Some typical fuzzy implication operators are applied to the construction of a fuzzy model of a d.c. series motor. A root-mean-square error is used as the criterion of the fuzzy model's adequacy to the real system. A number of mathematical operations necessary for the implementation of the fuzzy model are used as the criterion by which the fuzzy model's applicability if estimated from the point of view of computing techniques. The best types of fuzzy relations, representing fuzzy models of a real system, are chosen in order to secure the least root-mean-square error with minimal number of mathematical operations necessary for computer implementation.     

A study of condensation of trithiane hexaoxide with formaldehyde

The title reaction catalyzed by NaOH in aqueous media was studied. The oligomeric products formed are characterized in terms of their yield, structure, etc. The effects of reaction parameters and media are also discussed. The reaction mechanism is proposed. © 1993 John Wiley & Sons, Inc.     

Ethoxy Groups on ZrO2, CuO,and CuO/ZrO2 Studied by IR Spectroscopy

The formation, properties, decomposition and reactions of ethoxy groups on ZrO₂, CuO, and CuO/ZrO₂ were followed by IR spectroscopy. The reaction of ethanol with terminal Zr-OH groups leads to the formation of monodendate ethoxy groups (type I), whereas the reaction of ethanol with tribridged Zr-OH grups results in the formation of bidendate ethoxyls (type II). In both cases, water is produced. Ethoxy groups of type II were also formed on CuO. The type of the surface species detected after interaction of ethanol with CuO/ZrO₂ was the same as detected for both oxides (i.e., ZrO₂ and CuO) separately. This suggests that no new phase was formed in the mixed oxide system. At higher temperatures, ethoxy groups were oxidized forming acetate ions. Gaseous ethanol present in the cell was oxidized to acetaldehyde without the intermediacy of ethoxy groups.     

Komplexbildende Eigenschaften des 3,5-Dimethylpyrazols

Zusammenfassung 3,5-Dimethylpyrazol bildet in Anwesenheit von Rhodanid mit Kupfer(II) einen gefärbten Komplex, der in Chloroform leicht löslich ist. Diese Reaktion wurde zur photometrischen Bestimmung von 10 bis 100g Cu/5 ml verwendet.

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Summary A colored complex, that is readily soluble in chloroform, is formed by copper(II) with 3,5-dimethylpyrazole in the presence of thiocyanate. This reaction was employed for the photometric determination of 10 to 100g Cu/5 ml.

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Résumé Le diméthyl-3,5 pyrazol forme avec le cuivre-II en présence de thiocyanate, un complexe coloré, facilement soluble dans le chloroforme. On a utilisé cette réaction pour le dosage photométrique de 10 à 100g Cu/5 ml.

     

On the universality of Einstein equations

It is proved that a Lagrangian field theory based on a linear connection in space-time is equivalent to Einstein's general relativity interacting with additional matter fields.