Relationships between DFT/RRKM Branching Ratios of the Complementary Fragment Ions [C5H5O]+ and [M – C5H5O]+ and Relative Abundances in the EI Mass Spectrum of N-(2-Furylmethyl)aniline

2012 ◽  
Vol 116 (49) ◽  
pp. 12136-12147 ◽  
Author(s):  
Wilmer E. Vallejo Narváez ◽  
Paula V. Bacca Villota ◽  
Eduardo A. Solano Espinoza
Keyword(s):  
Mass Spectrum ◽  
Branching Ratios ◽  
Fragment Ions ◽  
Complementary Fragment ◽  
Relative Abundances

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.

THE MASS SPECTRUM OF TITANIUM TETRACHLORIDE

1954 ◽  
Vol 32 (11) ◽  
pp. 1039-1043 ◽  
Author(s):  
J. E. Hogg
Keyword(s):  
Titanium Dioxide ◽  
Mass Spectrum ◽  
Mass Spectrometer ◽  
Titanium Tetrachloride ◽  
Chlorine Isotopes ◽  
Commercial Titanium ◽  
Relative Abundances ◽  
Type Mass

An investigation of the mass spectrum of titanium tetrachloride prepared from both commercial titanium dioxide and titanium minerals has been carried out, using a 180° Nier-type mass spectrometer. Values for the relative abundances of the titanium and chlorine isotopes have been found. Measurements of the singly ionized trichloride group show that any variation in the relative abundances of the isotopes of titanium contained in these samples must be less than one per cent.

Spectres de masse d'hydrazino-2 benzo- et naphtothiazoles et d'hydrazones des méthyl-3 benzo- et naphtothiazolinones-2

1975 ◽  
Vol 53 (23) ◽  
pp. 3677-3680 ◽  
Author(s):  
Jean-Claude Richer ◽  
Philippe Lapointe ◽  
Martine Beljean ◽  
Michel Pays
Keyword(s):  
Mass Spectrum ◽  
Mass Spectra ◽  
Base Peak ◽  
Molecular Ion ◽  
Ion Fragmentation ◽  
Fragment Ions ◽  
Sampling Probe ◽  
Electron Impact Mass ◽  
Impact Mass ◽  
Hydrazone Form

Electron impact mass spectra are reported for the hydrazones of 3-methyl-2-benzothiazolinone (1), of 4-, 5-, 6-, and 7-chloro-3-methylbenzo-2-thiazolinones (2, 3, 4, and 5) and of 3-methyl-naphtho[2,1-d]-2-thiazolinone (6), as well as for 2-hydrazinobenzothiazole (7), for 4-, 5-, 6-, and 7-chloro-2-hydrazinobenzothiazoles (8, 9, 10, and 11) and for 2-hydrazinonaphtho[2,1-d]thiazole (12). The results obtained in the two series are compared. The 2-hydrazone and 3-methyl-benzo-2-thiazolinone and its derivatives all form a base peak corresponding to the molecular ion; fragmentation proceeds mainly by successive losses of·NH2, HCN, HCN, and then CS. Initial losses of N2H2, NH·, and NH3 are minor fragmentation routes.In the case of 2-hydrazinobenzothiazole and its derivatives, the base peak is still that of the molecular ion; however, the relative proportions of the various fragment ions vary with the position of sampling probe inside the apparatus. Thus it is concluded that the observed mass spectrum is that of a mixture of the possible hydrazone-hydrazine tautomers. The principal fragmentations involve the initial loss of NH3 (leading to a stabilized ion), of NH2· (probably from the hydrazone form), and of N2H2.(Journal Translation)

scholarly journals Free-radical-induced formation of an 8,5′-cyclo-2′-deoxyguanosine moiety in deoxyribonucleic acid

1986 ◽  
Vol 238 (1) ◽  
pp. 247-254 ◽  
Author(s):  
M Dizdaroglu
Keyword(s):  
Mass Spectrum ◽  
Covalent Bond ◽  
Gas Chromatography Mass Spectrometry ◽  
Oh Radicals ◽  
Selected Ion Monitoring ◽  
Isolation And Identification ◽  
Fragment Ions ◽  
Theoretical Mass ◽  
Dilute Aqueous Solutions ◽  
Fragmentation Patterns

Isolation and identification of a novel .OH-induced product, namely an 8,5′-cyclo-2′-deoxyguanosine moiety, in DNA and 2′-deoxyguanosine are described. .OH radicals were generated in dilute aqueous solutions by gamma-irradiation. Analyses of 2′-deoxyguanosine and enzymic hydrolysates of DNA by gas chromatography-mass spectrometry (g.c.-m.s.) after trimethylsilylation showed the presence of 8,5-cyclo-2′-deoxyguanosine on the basis of its fragment ions. This product was isolated by h.p.l.c. Its u.v. and n.m.r. spectra taken were in agreement with the structure suggested by its mass spectrum. Exact masses of the typical ions from the mass spectrum of the trimethylsilyl derivative of this product were measured by high-resolution m.s. The values found were in excellent agreement with the theoretical mass derived from the suggested fragmentation patterns. Both (5′R)- and (5′S)-epimers of 8,5′-cyclo-2′-deoxyguanosine were observed. These two diastereomers were separated from each other by g.c. as well as by h.p.l.c. The assignment of the epimers was accomplished on the basis of the n.m.r. data. The formation of 8,5′-cyclo-2′-deoxyguanosine was suppressed by the presence of O2 in the solutions. The use of g.c.-m.s. with the selected-ion monitoring technique facilitated the detection of 8,5′-cyclo-2′-deoxyguanosine in DNA at radiation doses as low as 1 Gy. Its mechanism of formation probably involves hydrogen atom abstraction by .OH radicals from the C-5′ of the 2′-deoxyguanosine moiety followed by intramolecular cyclization with the formation of a covalent bond between the C-5′ and C-8 and subsequent oxidation of the resulting N-7-centred radical.

scholarly journals Structural investigation of sparfloxacin drug using mass spec-trometry and MNDO semi-empirical molecular orbital calcu-lations

2018 ◽  
Vol 6 (1) ◽  
pp. 74 ◽  
Author(s):  
Mamoun Sarhan Mahmoud Abd El-kareem ◽  
Mohamed ElDesawy ◽  
Mohamed Hawash ◽  
Magd El dain Fahmy Ahmed
Keyword(s):  
Mass Spectrum ◽  
Molecular Orbital ◽  
Mass Spectra ◽  
Orbital Method ◽  
Moderate Activity ◽  
Fragment Ions ◽  
Mass Spec ◽  
Main Fragment ◽  
Semi Empirical ◽  
Fragmentation Processes

Sparfloxacin is a broad spectrum antibacterial fluoroquinolone against some microorganisms including gram-positive and gram-negative bacteria and exhibits moderate activity against anaerobes and mycobacteria. Sparfloxacin is well tolerated and the intake of food has no adverse effect on the pharmacokinetic features (Blondeau 1999, Stahlmann et al. 1998). For the medical important of this drug author have been study its structure by recording and investigate its electron ionization (EI) mass spectra at different electron energies 70 and 15 eV. Also, the chemical ionization (CI) mass spectrum has been recorded and investigated. The main fragmentation processes in EI and CI have elucidated and discussed. The main fragment ions in EI mass spectra are [M-C4H8N] + and fragment [M- C4H8N- CO2] +, while [MH- CO2]+ ion are the most fragment ion in CI mass spectrum. On the other hand, the molecular structure optimization of sparfloxacin was calculated using the modified neglect of diatomic overlap (MNDO) semi-empirical molecular orbital method. Also, the thermochemical data such as heat of formations, total energy, ionization energy, electron affinity and dipole moment have been calculated and discussed.

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