V. D. Shteingarts

Fluorine-containing carbocations. II. Polyfluorinated benzyl cations

Abstract When dissolved in SbF5, polyfluorinated trifluoromethylbenzenes produce polyfluorinated α,α-difluorobenzyl ions. The 19F chemicals shifts and spin-spin coupling constants J(FF) have been analysed in terms of the resonance structures which contribute to the overall positive charge distribution. The influence of halogen atoms situated at position 4 on the downfield signal shift of α-fluorines follows the sequence F > Cl > Br which is opposite to that observed for 4-XC6H4CF2+ ions.

Fluorine-containing carbocations. III. Alkylation of polyfluorobenzenes with polyfluorinated α,α-difluorobenzyl cations and generation of polyfluorinated α-fluorodiphenylmethyl cations

Abstract Alkylation of incompletely fluorinated benzenes with polyfluorinated α,α-difluorobenzyl cations in an SbF 5 medium results in the formation of polyfluorinated α-fluorodiphenylmethyl cations whose precursors are the primary products of alkylation, i.e. the corresponding polyfluorinated α,α-difluorodiphenylmethanes. The influence of substituents on the 19 F chemical shifts and spin-spin coupling constants J (FF) has been analysed in terms of their effects on contributions of the resonance structures controlling the positive charge distrubution on the coplanarity of the phenyl rings and the plane of the α-carbon bonds.

Fluorine-containing carbocations. IV. The use of salt solutions of stable polyfluorinated α,α-difluorobenzyl and α-fluorodiphenylmethyl cations in antimony pentafluoride in the synthesis of polyfluorinated benzoic acids, benzophenones and diphenyldifluoromethanes

Abstract Polyfluorinated benzoic acids have been prepared by the hydrolysis of solutions of salts of polyfluorinated α,α-difluorobenzyl cations in SbF 5 . Polyfluorinated benzophenones and diphenyldifluoromethanes have been obtained both by hydrolysis and by pouring into HF solutions of the salts of polyfluorinated α-fluorodiphenylmethyl cations.

Polyfluoroaromatic cation radicals

The reaction of SbF5 with polyfluoroderivatives of benzene and diphenyl gave the corresponding cation radicals, which were characterized by their EPR spectra. This indicates the general character of formation of polyfluoroaromatic cation radicals in the reaction of strong electrophilic reagents with polyfluoroaromatic compounds.

REACTION OF AROMATIC COMPOUNDS WITH NUCLEOPHILIC REAGENTS IN A LIQUID AMMONIA MEDIUM. I. REPLACEMENT OF A HYDROGEN ATOM BY A HYDROXY GROUP IN AROMATIC NITRO COMPOUNDS IN THE PRESENCE OF POTASSIUM HYDROXIDE AND OXYGEN

Die Umsetzung von Nitrobenzol (I), p-Nitrodiphenyl (IV), 1-Nitronaphthalin (VI), 1,5-Dinitronaphthalin (IX) und 1,8-Dinitronaphthalin (XII) mit KOH und O2 in flussigem Ammoniak fuhrt zu den o- bzw. p-Nitrophenolen (II), (III) und (V) und den 2- bzw. 4-Hydroxynitronaphthalinen (VII), (VIII), (X), (XI), (XIII) und (XIV).

13C-NMR spectra of fluoro-substituted arenonium ions

1. The13C-NMR spectra of a number of fluoro-containing arenonium ions were obtained for the first time. 2. In the studied series of ions the ratio between the ΔδC and ΔδF values is approximately constant for the directly attached carbon atoms and fluorine atoms, which apparently indicates an approximately constant ratio of the charge fractions on the atoms of the C-F fragment.

Generation and some reactions of perhalogenated arenonium ions

Perhalogenated arenonium ions are formed by elimination of F– from perhalogenated cyclohexa-1,4-dienes by reaction with SbF5.