Radical cations, gaseous

Morkovnik et al. (1989) found experimentally that the addition of an equimolar amount of 4-morpholino- or 4-dimethylaminoaniline to a suspension of nitrosyl perchlorate in 100 % acetic acid, dioxan, or acetonitrile yields a mixture of the diazonium perchlorate and the perchlorate salt of the amine radical cation, with liberation of gaseous nitric oxide. Analogous results in benzene, including evidence for radicals by ESR spectroscopy and by spin trapping experiments, were obtained by Reszka et al. (1990). 

Fig. 11.2. Diagram of the components of an El source. Gaseous samples (gases or vaporized liquids or solids) are introduced into the ionization chamber using a reservoir with molecular leak, direct insertion probe or as an eluent from a GC column. The collimated stream of 70 eV electrons interacts with the neutral analyte molecules to generate stable radical cations (M+ ) and unstable radical cations (M+ ) that undergo dissociation reactions to form the characteristic fragment ions observed in many El mass spectra.

II. GASEOUS RADICAL CATIONS OF SOME DIENES AND POLYENES THERMOCHEMISTRY OF SOME TYPICAL REACTIONS... 

More recent work on the chemistry of gaseous 1,3,5-cycloheptatriene radical cations concerns the energetics and dynamics of the interconversion with ionized toluene and the competing losses of H from both isomers. Lifshitz and coworkers22,143 have reported on the details of the energy surface of the ions. Most importantly, the critical energies... 

Hammerum, S. Distonic Radical Cations in the Gaseous and Condensed Phase. Mass Spectrom. Rev. 1988, 7, 123-202. 

The gaseous dichlorocarbene radical cation reacted with alkyl halides via a fast electrophilic addition to form a covalently bonded intermediate (CI2C—X—R)+ in a Fourier transform ion cyclotron resonance mass spectrometer. This intermediate fragments either homolytically or heterolytically to produce net halogen atom or halogen ion transfer product. Addition of carbonyls to the carbene ion is followed by homolytic cleavage of the C-O bond to yield a new carbene radical cation. 

GASEOUS RADICAL CATIONS DERIVED EROM PHENOLS THERMOCHEMISTRY OE SOME TYPICAL SPECIES AND... 

The El-induced fragmentation of gaseous [4 + 2]- and [2 + 2]dicyclopentadiene radical cations has been studied by Roth and coworkers using Fourier transform ion cyclotron resonance mass spectrometry, and compared to the cleavage of these ions in solution using chemically induced dynamic nuclear polarization (CIDNP). Both in the gas and in the liquid phase, the isomers of the molecular ions formed by single C—C bond cleavage were observed. It is noteworthy that these distonic ions were termed non-vertical radical cations. 

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