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

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.

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Linearity and reproducibility of a sector field mass spectrometer utilizing an electron impact ion source. (France)

Vacuum ◽

10.1016/0042-207x(71)92645-5 ◽

1971 ◽

Vol 21 (6) ◽

pp. 243

Keyword(s):

Electron Impact ◽

Mass Spectrometer ◽

Ion Source ◽

Field Mass

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Hypervalent Molecular Cluster: C28H4

Materials Science Forum ◽

10.4028/www.scientific.net/msf.494.181 ◽

2005 ◽

Vol 494 ◽

pp. 181-186

Author(s):

M. Veljković ◽

O. Nešković ◽

A. Djerić ◽

S. Veličković ◽

V. Šipka

Keyword(s):

Mass Spectrometry ◽

Mass Spectrometer ◽

Source Parameters ◽

Carbon Cluster ◽

Ion Source ◽

Molecular Cluster ◽

Hydrogen Atoms ◽

Cluster Source ◽

The Impact

A growing number of recent publications on clusters reflect a tremendous interest in these particles. These studies reveal new fundamental physical and chemical aspects of matter. Clusters are called the fifth state of matter: liquid, solid, cluster, gas and plasma. In this work, a carbon cluster was generated by a spark cluster source and detected by single focusing mass spectrometer in situ. We examined the effects of cluster source parameters on the generation of carbon cluster and report our initial results. This method should be useful for studying the mechanism of fullerene formation. In the case when carbon clusters generated in plasma arc are carried by the Ar or H2 gas flow downstream through a vacuum chamber to the ion source of mass spectrometer, we obtained a small binary carbon cluster C28H4 (hydrogenated fullerene). The empty fullerene is tetravalent and strongly binds four hydrogen atoms, which significantly weakens two different sets of bonds and leads to an open-shell electronic structure. Conclusion is that endohedral C28H4 are hypervalent. We have demonstrated how in situ mass spectrometry has led to the rapid development of an important branch of synthetic fullerene chemistry that has yielded many new small fullerenes and related derivatives with novel structures and properties. The impact of mass spectrometry on the synthesis of fullerene derivatives is the subject of this paper. Significantly, a large fraction of products could be condensed on a specially designed collection plate, which allows further spectroscopic characterization of new derivatives.

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The formation of (CH3)7Si2+ in (CH3)4Si/CH4 mixtures and CH3− exchange reactions between (CH3)4Si, (CH3)4Ge, and (CH3)4Sn studied by high pressure mass spectrometry

Canadian Journal of Chemistry ◽

10.1139/v87-473 ◽

1987 ◽

Vol 65 (12) ◽

pp. 2849-2854 ◽

Cited By ~ 15

Author(s):

Anastasia C. M. Wojtyniak ◽

Xiaoping Li ◽

John A. Stone

Keyword(s):

Mass Spectrometry ◽

High Pressure ◽

Equilibrium Constant ◽

Mass Spectrometer ◽

Excellent Agreement ◽

Ion Source ◽

Methyl Groups ◽

Exchange Reactions ◽

Equilibrium Reactions ◽

Association Equilibrium

The association equilibrium [Formula: see text] has been studied in a high pressure mass spectrometer ion source using tetramethylsilane/methane mixtures. Measurement of the equilibrium constant over a range of temperatures yields ΔH0 = −22.3 ± 0.4 kcal mol−1 and ΔS0 = −35.2 ± 0.9 cal mol−1 K−1. Collision-assisted dissociation experiments suggest that the methyl groups retain their integrity in (CH3)7Si2+. Mixed ions such as (CH3)7SiGe+ and (CH3)7GeSn+ were not observed in mixtures of (CH3)4X and (CH3)4Y(X ≠ Y = Si, Ge, Sn). Instead CH3− transfer equilibrium reactions were observed viz. [Formula: see text] (ΔH0 = −10.2 ± 1.2 kcal mol−1, ΔS0 = −3.7 ± 2.4 cal K−1 mol−1) and [Formula: see text], ΔS0 = −0.9 ± 1.6 cal K−1 mol−1. These are in excellent agreement with some published differences in appearance potentials for (CH3)3X+ from (CH3)4X (X = Si, Ge, Sn).

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Application of Dual Electron Impact-Chemical Ionization Ion Source to Gaschromatograph-Mass spectrometer

Journal of the Mass Spectrometry Society of Japan ◽

10.5702/massspec1953.24.139 ◽

1976 ◽

Vol 24 (1) ◽

pp. 139-147

Author(s):

MASAYA IWANAGA ◽

KIYOSHI HOSOI ◽

NORIO KAMESHIMA ◽

SHOZO ONISHI

Keyword(s):

Electron Impact ◽

Mass Spectrometer ◽

Chemical Ionization ◽

Ion Source

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Fragmentation pathways in the mass spectra of isomeric phenylazoxypyridine-N-oxides

Canadian Journal of Chemistry ◽

10.1139/v92-137 ◽

1992 ◽

Vol 70 (4) ◽

pp. 1028-1032 ◽

Cited By ~ 7

Author(s):

Nigel J. Bunce ◽

H. Stewart McKinnon ◽

Randy J. Schnurr ◽

Sam R. Keum ◽

Erwin Buncel

Keyword(s):

Mass Spectrometry ◽

Tandem Mass Spectrometry ◽

Electron Impact ◽

Mass Spectra ◽

Chemical Reduction ◽

Ion Source ◽

Tandem Mass ◽

Mass Spectral Fragmentation ◽

Fragmentation Pathways ◽

Mass Spectral

The mass spectral fragmentation pathways of a series of phenylazoxypyridine-N-oxides have been studied under electron impact conditions using tandem mass spectrometry. Besides simple C—N cleavages, the azoxypyridine-N-oxides undergo deep-seated rearrangements directly from the molecular ion. In addition, the spectra are complicated by a purely chemical reduction of the N—O functionalities that occurs in the ion source prior to ionization.

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