The volatile constituents of the essential oil of local Pelargonium graveolens growing in Egypt was investigated by gas chromatography–mass spectrometry (GC–MS), and the main constituents were citronellol (27.67%), cis-Menthone (10.23%), linalool (10.05%), eudesmol (9.40%), geraniol formate 6.87%, and rose oxide (5.77%), which represent the major components in the obtained GC total ion chromatogram. The structural determination of the main constitutes based on their electron ionization mass spectra have been investigated. The MS of these compounds are absolutely identical in mass values of peaks of fragment ions, where their relative intensities have minor differences. In the spectra of all studied compounds, the observed characteristic ions were [M-H2O]+ and [M-CH3]+. The latter has a structure with m/z 69, 83. Different quantum parameters were obtained using Modified Neglect of Diatomic Overlap (MNDO) semi-empirical method as total energy, binding energy, heat of formations, ionization energy, the energy of highest occupied molecular orbital (HOMO), the energy of the lowest unoccupied molecular orbital (LUMO), energy gap Δ, and dipole moment. The antibacterial and antifungal activities of P. graveolens essential oil and identified compounds were tested against wide collection of organisms. The individual identified compounds in the essential oil—citronellol, cis-Menthone, and linalool (except eudesmol)—showed comparable activity to antibiotics. The most active isolated compound was the citronellol and the lowest MIC was found against E. coli. The essential oil showed high antifungal effects and this activity was attributed to cis-Menthone, eudesmol, and citronellol (excluding linalool). cis-Menthone was the most active compound against selected fungi followed by the eudesmol The study recommends local P. graveolens and identified active compounds for further applications in the pharmaceutical industries.
In the present communication we have measured ionization energies (ZE) for molecular ions M+' as well as appearance energies ( A E ) for [M-l]+ fragment ions at threshold produced from benzyl alcohol, benzyl amine and benzyl cyanide. The electron impact, ZE and A E data were obtained by using an Atlas CH-4 mass spectrometer and the data were treated using the deconvoluted first differential (DFD) technique.' Metastable peaks associated with the formation of [M -1]+ fragment ions were recorded-using an MM 16F mass spectrometer-at low electron energy (9-12 eV) in order to avoid interference from normal fragment ions. Kinetic energy release values ( were calculated2 from metastable peak width at half height. Molecular Ions. ZE and A E [M -1]+ values are presented in Table 1 together with K E released and AH, values calculated for [M -1]+ ions.
An energetic study of the production of [C7H,N]+ and [C6H7]+ fragment ions from o-toluidine and Nmethylaniline is reported. The mechanisms for the formation of the ions are suggested. Metastable peaks associated with the formation and fragmentation of reactive [ C,H,N I + and I C6H7 1 .+ ions were detected and kinetic energy released were determined. The results indicate that the IC,H,N]+ ion is formed at threshold from o-toluidine with an aminotropylium structure whereas for N-methylaniline the ion is formed with an N-phenylmethaniminium structure. [ C,H,] + ions are believed to be formed at threshold from the two precursors with a protonated benzene structure.
The electron ionization mass spectra of 2-and 4-chlorodiphenylamine and 2-and 4-bromodiphenylamine are reported. All the spectra are characterized by strong molecular ion signals, corresponding to the base peak. Two primary fragmentations of significance include the expulsion of the substituents X and HX (X = halogen) from the four compounds. Further dissociation of the primary fragment ions results in the formation of some secondary decomposition ions having low or negligible relative abundances.
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