Cation radicals. 47. Reaction of perylene cation radical with fluoride ion and of perylene with xenon difluoride. Formation of 1-fluoro-, 3-fluoro-, and a difluoroperylene. Complications with chloride ion impurity

1981 ◽  
Vol 46 (15) ◽  
pp. 3139-3141 ◽  
Author(s):  
M. T. Stephenson ◽  
H. J. Shine
Keyword(s):  
Cation Radical ◽  
Chloride Ion ◽  
Fluoride Ion ◽  
Xenon Difluoride ◽  
Cation Radicals ◽  
Ion Impurity

Oxidative fluorination in the Ph2SO–XeF2–Cl− system and fluorine exchange in the Ph2S(O)F2–Ph2S(O)F+ system

1996 ◽  
Vol 74 (11) ◽  
pp. 2002-2007 ◽  
Author(s):  
Xiaobo Ou ◽  
Alexander F. Janzen
Keyword(s):  
Nmr Spectroscopy ◽  
Ab Initio ◽  
Key Words ◽  
Exchange Process ◽  
Chloride Ion ◽  
Fluoride Ion ◽  
Molecular Orbital Calculations ◽  
Xenon Difluoride ◽  
Mild Conditions ◽  
C Nmr

Oxidative fluorination of diphenyl sulfoxide with xenon difluoride occurs under mild conditions in the presence of chloride ion to give Ph2S(O)F2 in quantitative yield. Chloride ion appears to react with xenon difluoride to generate fluoride ion, and a mechanism of oxidative fluorination is proposed that involves anionic Ph2S(O)F− and radical Ph2S(O)F• intermediates. Addition of cationic Ph2S(O)F+ to Ph2S(O)F2 initiates rapid fluorine exchange, presumably via a symmetrical fluorine-bridged intermediate, and this exchange process was monitored by 13C and 19F NMR spectroscopy. In the presence of chloride ion, Ph2S(O)Cl2 is formed and can be identified by 13C NMR and by its hydrolysis to Ph2SO2. Mechanisms are proposed for these reactions, and ab initio molecular orbital calculations (GAUSSIAN92) were carried out of the postulated intermediates. Key words: preparation of Ph2S(O)F2, Ph2S(O)F+, and Ph2S(O)Cl2; oxidative fluorination in the Ph2SO–XeF2–Cl− system; fluorine exchange in the Ph2S(O)F2–Ph2S(O)F+ system.

scholarly journals Methyl-Eliminierung aus dem metastabilen Homoadamantan-Radikalkation / Methyl Loss from Metastable Homoadamantane Cation Radical

1980 ◽  
Vol 35 (2) ◽  
pp. 207-211 ◽  
Author(s):  
Helmut Schwarz ◽  
Chrysostomos Wesdemiotis ◽  
Thomas Weiske ◽  
Helmut Schwarz ◽  
Chrysostomos Wesdemiotis ◽  
...  
Keyword(s):  
Experimental Evidence ◽  
Cation Radical ◽  
Model Calculations ◽  
Direct Ionization ◽  
Cation Radicals

Abstract It is demonstrated that methyl loss from ionized homoadamantane (1) yields exclusively the 1-adamantyl cation (4); there is no experimental evidence for the formation of the secondary adamantyl cation (5). From both model calculations and the investigation of [4-13C]-homoadamantane (1a) and 1(13C-methyl)adamantane (2a) it is concluded, that 24% of the metastable homoadamantane cation radicals dissociate after one isomerization (1→2); the remaining 76% are able to undergo at least a second (degenerate) isomerization cycle (2→1→2) prior to methyl loss. 78% of metastable 1-methyl-adamantane cation radical, obtained upon direct ionization of the corresponding neutral hydrocarbon, dissociate directly, whereas the loss of methyl from the remaining 22% is preceded by an isomerization 2 →1 →2.

Effect of substitution on the redox behaviour and EPR spectra of zinc(II) substituted tetraphenylporphyrin cation radicals

2000 ◽  
Vol 04 (02) ◽  
pp. 192-201 ◽  
Author(s):  
PARESH C. DAVE ◽  
D. SRINIVAS
Keyword(s):  
Ground State ◽  
Cation Radical ◽  
Molecular Geometry ◽  
Chemical Oxidation ◽  
Electronic Ground State ◽  
Epr Spectra ◽  
Redox Behaviour ◽  
Cation Radicals ◽  
First Time ◽  
Electronic Ground

Substituted tetraphenylporphyrinatozinc(II) complexes have been synthesized and characterized by various physicochemical techniques. The effects of substitution and counterions on the redox behaviour and EPR spectra have been examined. The EPR spectra revealed that chemical oxidation with bromine yields ZnT ( X - P ) P + Br - (species I) and a brominated tetraphenylporphyrin cation radical (species II). The former exhibits a labile electronic ground state (with 2 A 2 u ground state transforming into 2 A 1 u at 175 K), while the latter is characterized by a 2 A 1 u state. The lability in the electronic ground state for species I is discussed in terms of the change in molecular geometry as the temperature is lowered. The EPR spectra also revealed for the first time the formation of dimeric agglomerates of TPP cation radicals in low concentration below the electronic transition (i.e. near 170 K) wherein the paramagnetic sites are antiferromagnetically coupled.

Vicinal-diaryl interactions in stilbenoid hydrocarbons as observed in the through-space charge delocalization of their cation radicals

1999 ◽  
Vol 77 (5-6) ◽  
pp. 913-921 ◽  
Author(s):  
Rajendra Rathore ◽  
Jay K Kochi
Keyword(s):  
Space Charge ◽  
Cation Radical ◽  
Conformational Preference ◽  
Charge Delocalization ◽  
X Ray ◽  
X Ray Crystallography ◽  
Cation Radicals ◽  
Near Ir ◽  
Aromatic Interactions ◽  
Vis Spectroscopy

The conformational preference of vicinal or 1,2-phenyl groups is probed in two classes of ring-substituted 1,2-diphenylbicyclooctene (stilbenoid) hydrocarbons 1a-1d and 2a-2c. UV-vis spectroscopy reveals, and X-ray crystallography verifies, the intramolecular (edge-to-face) orientation for the phenyl-phenyl interaction in stilbenoids 1a-1d. Most importantly, when two pairs of ortho-methyl substituents are present, the cofacial phenyl groups in the stilbenoid donors are established by X-ray crystallography and spectrally observed in the cation radicals (2a+.-2c+.) by the appearance of new bands with strong absorptions in the near IR with λmax = 1100-1315 nm, analogous to those previously observed in intermolecular (aromatic) interactions of aromatic cation radicals.Key words: stilbenoid hydrocarbon, cation radical, aryl-aryl interaction.

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