Effect of structural factors on the disintegration of the molecular ions of nitrophenylisoxazoles during electron impact

1974 ◽  
Vol 10 (4) ◽  
pp. 393-396
Author(s):  
K. K. Zhigulev ◽  
R. A. Khmel'nitskii ◽  
S. D. Sokolov ◽  
N. M. Przheval'skii
Keyword(s):  
Electron Impact ◽  
Molecular Ions ◽  
Structural Factors

Mass spectra of 4,4-dimethyl-A-homo-4a,6-cholestadien-3-ols, 4,4-dimethyl-A-homo-5-cholestene-3,4a-diols and their derivatives

1982 ◽  
Vol 47 (10) ◽  
pp. 2768-2778
Author(s):  
Antonín Trka ◽  
Helena Velgová
Keyword(s):  
Carbon Atom ◽  
Electron Impact ◽  
Mass Spectra ◽  
Molecular Ions

Partial electron impact induced mass spectra are given of 3α-hydroxy-, 3β-hydroxy-, 3β-methoxy-, 3α-acetoxy- and 3β-acetoxy-4,4-dimethyl-A-homo-4a,6-cholestadienes, 3α,5α-epoxy-4,4-dimethyl-A-homo-5-cholestane, isomeric 4,4-dimethyl-A-homo-5-cholestene-3α(β),4aα(β)-diols, their 3-acetoxy derivatives and 3-methyl ethers. The fragmentation of the molecular ions of these substances involves the usual elimination of substituents (in the form of H2O, CH3OH, CH3COOH, CH2CO), but the most abundant and characteristic ions are products of the contraction of ring A (to a six- or five-membered one), accompanied by expulsion of a fragment containing the carbon atom C(4) with both methyls.

Experimental studies of electron impact dissociation of molecular ions

1996 ◽  
Author(s):  
Nada Djurić ◽  
Yang-Soo Chung ◽  
Barry Wallbank ◽  
Gordon H. Dunn
Keyword(s):  
Electron Impact ◽  
Experimental Studies ◽  
Molecular Ions ◽  
Electron Impact Dissociation

Water loss from ester molecular ions upon electron impact

1979 ◽  
Vol 14 (5) ◽  
pp. 286-288 ◽  
Author(s):  
Theodore L. Folk ◽  
Lawson G. Wideman ◽  
Kirkwood S. Cottman
Keyword(s):  
Electron Impact ◽  
Water Loss ◽  
Molecular Ions

Rotational excitation of molecular ions by electron impact under interstellar conditions

1981 ◽  
Vol 247 ◽  
pp. 936 ◽  
Author(s):  
S. S. Bhattacharyya ◽  
B. Bhattacharyya ◽  
M. V. Narayan
Keyword(s):  
Electron Impact ◽  
Molecular Ions ◽  
Rotational Excitation

Mass spectral investigations on selenium compounds. II. The behaviour of meta-and para-substituted benzeneseleninic acids and of meta-nitrophenyl selenocyanate under electron impact

1982 ◽  
Vol 35 (7) ◽  
pp. 1365 ◽  
Author(s):  
A Benedetti ◽  
C Preti ◽  
L Tassi ◽  
G Tosi
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectrum ◽  
Electron Impact ◽  
Molecular Ions ◽  
Selenium Compounds ◽  
Molecular Ion ◽  
Mass Spectral ◽  
Low Intensity ◽  
Fragment Ions

Substituted benzeneseleninic acids of the type XC6H4SeO2H (X = m-Cl, p-Cl, m-Br, p-Br, p-Me, m-NO2, p-NO2) have been investigated by mass spectrometry. The fragmentation modes and the fragment ions are discussed and compared with those obtained from the mass spectrum of m-nitro-phenyl selenocyanate, O2NC6H4SeCN. Generally, as regards the acids, besides very weak peaks due to the molecular ions, a number of peaks at higher mass numbers and of greater intensity is observed; these peaks are in multiplets typical of the presence of two selenium atoms, and they correspond to the disubstituted diphenyl diselenides of the type XC6H4SeSeC6H4X. m-Nitrophenyl selenocyanate shows an intense molecular ion peak and the relative fragmentation, while the peak due to the diselenide is of very low intensity.

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