The computer processing and interpretation of mass spectral information. VI—computing the isotopic spectrum of assumed composition

J. Am. Soc. Mass Spectrom.

Belokon

et al. 2011

Our previous investigations showed that homolytic reactions of C 60 with a number of perfluoroorganic and organomercury(II) compounds occurring under electron impact (EI) in the ionization chamber (IC) of a mass spectrometer could predict the reactivity of C 60 towards these compounds in solution or solid state. To expand the scope of this statement, C 60 and C 70 have been reacted with ketones RCOR 1 , where R and R 1 are alkyl, aryl, benzyl, and CF 3 , in an IC under EI to yield products of the addition of R · and R 1 · radicals to the fullerenes, paramagnetic ones being stabilized by hydrogen addition and loss. Experimental evidence in support of a mechanism involving homolytic dissociation of ketone molecules via superexcited states to afford these radicals that react with the fullerenes at the IC surface has been obtained. As anticipated, the reactions between C 60 and several ketones conducted in solution under UV irradiation have afforded Me-, Ph-, and CF 3 -derivatives of C 60 . However, some other products have been identified by mass spectrometry and their formation is reasonably explained. When decalin has been employed as a solvent, decalinyl derivatives of the fullerene have been found among the products and the (9-decalinyl)fullerenyl radical has been registered by EPR. Thus, incomplete but reasonable conformity of the results of the reactions of fullerenes with ketones in an IC under EI with those of the reactions of the same reagents in solution under UV irradiation has been demonstrated, and the former results can predict the latter ones to a reasonable extent.

Section: Resultsmentioning

confidence: 99%

Homolytic Reactive Mass Spectrometry of Fullerenes: Interaction of C₆₀ and C₇₀ with Ketones in the Electron Impact Ion Source of a Mass Spectrometer and the Comparison of Results with Those of Photochemical Reactions of C₆₀ with Several Ketones in Solution

Shilova

J. Am. Soc. Mass Spectrom.

Belokon

et al. 2011

“…First, the AELITA program package is used to calculate the monoisotopic spectra for ions composed of the most abundant isotopes of the elements ( 12 C, 19 F and 1 H in this case) (32). Second, the iterative procedure, using the intensities of the first ion peaks in the groups (at m/z 909 and 858, respectively) as starting values and the SCIPE program package for subtraction of the contributions from 13 Ccontaining ions, is employed (33). For the first group of ions both methods yield similar results (Table 1).…”

Section: Resultsmentioning

confidence: 99%

Trifluoromethylation of C₆₀and C₇₀with Mercury(II) Trifluoroacetate

Fullerenes, Nanotubes and Carbon Nanostructures

Bashilov

Tatyana

et al. 2009

Fullerenes C 60 and C 70 are shown to react with Hg(CF 3 COO) 2 in the ionization chamber of the electron impact source of a mass spectrometer at 300 and 310uC, yielding trifluoromethylated derivatives of the fullerenes with up to six and two CF 3 addends, respectively. For some of the products the reactions are accompanied by hydrogen addition. Based on previous mechanistic studies of the analogous reactions of C 60 with the Scherer radical (C 9 F 19 N), a mixture of perfluoronones (C 9 F 18 ), and acetone, a plausible scheme is proposed for the processes. It involves formation of the intermediate CF 3 radicals owing to electron impact or thermally initiated homolytic dissociation of the mercury(II) salt, and their further reaction with the fullerenes at the surface of the ionization chamber. Heating mixtures of the reagents under argon at 300-310uC also yields trifluoromethylated fullerenes, in agreement with the results obtained with the ionization chamber.

“…Table 2 gives the monoisotopic ( 12 C, 1 H) spectrum for the reaction of tetramethylsilane (1) with C 60 . It was obtained by summarizing peaks of 52 magnetic scans, iterative use of the program SCIPE, and averaging the results over 3 runs [29]. Data listed in Table 2 demonstratively support the fact of hydrogen addition and loss.…”

Section: Reactions In the Ic Of A Massmentioning

confidence: 94%

Interaction of Fullerenes with Organosilanes in the Ionization Chamber of a Mass Spectrometer under Electron Impact and the Reaction of C₆₀with Tetraphenylsilane in Solution under UV Irradiation

Journal of Spectroscopy

Shilova

Плешкова

et al. 2016

C60was shown to react with organosilanes Me4Si, Ph2SiH2, Ph2MeSiH, Ph4Si, andα-naphthylphenylmethylsilane in the electron ionization ion source of a mass spectrometer with the transfer of the corresponding organic radicals (Me, Ph, andα-naphthyl) from the silanes to the fullerene. The reactions were accompanied by hydrogen addition to some products and hydrogen loss from them. C70reacted with Me4Si analogously. A reaction mechanism involving homolytic dissociation of the silanes under electron impact to the corresponding organic radicals, which react further with C60at the surface of the ionization chamber of the mass spectrometer to give the respective adducts, was offered. A mechanistic study of the reaction of C60with Me4Si supported it. No silicon containing derivatives of the fullerenes were found. C60reacted with Ph4Si in solution under UV irradiation in a similar fashion furnishing phenyl derivatives of the fullerene. These results provide an additional support to the hypothesis formulated earlier thatthe homolytic reactive mass spectrometry of fullerenes (the reactions of fullerenes with other species in the ionization chambers of mass spectrometers and their mass spectral monitoring)can predict the reactivity of them toward the same reagents in solution to a significant extent.