Electron impact studies. LVI. The fluorenyl and phenalenyl cations. The application of metastable characteristics

1970 ◽  
Vol 23 (7) ◽  
pp. 1431 ◽  
Author(s):  
JH Bowie ◽  
TK Bradshaw
Keyword(s):  
Electron Impact ◽  
Mass Spectrometer ◽  
Mass Spectra ◽  
Impact Studies ◽  
Double Focusing

A study of the abundances of certain metastable peaks formed by the de- composition of ions in the first and second field-free regions of a double-focusing mass spectrometer has shown that the M-1 ions (m/e 165) in the mass spectra of fluorene and phenalene have different structures. Correlations based on these structures have been obtained for C13H9+ species formed from different systems.

The Decomposition of Benzene and Deuterated Benzenes under Electron Impact

1967 ◽  
Vol 22 (4) ◽  
pp. 454-459 ◽  
Author(s):  
K. R. Jennings
Keyword(s):  
Electron Impact ◽  
Mass Spectrometer ◽  
Mass Spectra ◽  
Charged Species ◽  
Decomposition Reactions ◽  
Fragment Ions ◽  
Double Focusing ◽  
Doubly Charged

Metastable transitions have been observed in the mass spectra of benzene, hexadeutero-benzene, 1,4-dideuterobenzene and 1,3,5-trideuterobenzene using a double-focusing mass spectrometer. Decomposition maps have been obtained for each substance and decomposition reactions leading to the production of all significant fragment ions have been suggested. Metastable transitions of several doubly-charged species were found. Loss if identity by the H and D atoms of the partly-deuterated benzenes was observed in metastable transitions in their mass spectra, indicating that rapid isomerization occurs before fragmentation.

Electron impact studies. LXXX. Hydrogen-scrambling processes in 'doubly charged ion' mass spectra

1973 ◽  
Vol 26 (9) ◽  
pp. 2019 ◽  
Author(s):  
T Blumenthal ◽  
JH Bowie ◽  
SG Hart
Keyword(s):  
Electron Impact ◽  
Mass Spectrometer ◽  
Mass Spectra ◽  
Mass Range ◽  
Sensitivity Enhancement ◽  
Impact Studies ◽  
Doubly Charged ◽  
Hydrogen Scrambling

A device is described which allows the measurement of ?doubly charged ion? mass spectra on the m/e 300 mass range of an Hitachi Perkin-Elmer RMU7 mass spectrometer. The unit gives a sensitivity enhancement 110 times that described in previous papers, and has been used to study hydrogen-scrambling and metastable processes which occur in the ?doubly charged ion? spectra of a range of simple benzenoid derivatives.

Electron impact studies. VI. Mass spectra of esters and thioesters. Skeletal rearrangement on electron impact

1967 ◽  
Vol 20 (4) ◽  
pp. 689 ◽  
Author(s):  
JH Bowie ◽  
RG Cooks ◽  
P Jakobsen ◽  
S Lawesson ◽  
G Schroll
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
High Resolution ◽  
Electron Impact ◽  
Mass Spectra ◽  
Skeletal Rearrangement ◽  
Unsaturated Esters ◽  
Impact Studies ◽  
Unsaturated Alcohols ◽  
Metastable Ions

The mass spectra of representative series of simple alkyl acetoacetates, alkyl acetothioacetates, and some unsaturated esters derived from unsaturated alcohols or phenols are reported and discussed. The fragmentation schemes have been established by high resolution measurements, appropriate metastable ions, and by deuterium and 18O labelling. Many of the spectra show significant skeletal rearrangement fragments arising from either loss of carbon monoxide or carbon dioxide.

Electron impact studies. CVIII. Negative-ion mass spectra of the oxime group

1976 ◽  
Vol 29 (11) ◽  
pp. 2437 ◽  
Author(s):  
JH Bowie ◽  
S Janposri
Keyword(s):  
Electron Impact ◽  
Mass Spectra ◽  
Major Product ◽  
Negative Ion ◽  
Oxime Group ◽  
Impact Studies ◽  
Molecular Anions

Molecular anions derived from Ar-CH=NOH systems fragment by the process [MI- → [M-H2O]- to yield pronounced peaks corresponding to [ArCN]-. Molecular anions from Ar(CH2)nC(NOH)Ph (n = 0-2) also eliminate H2O, but the mechanisms are often complex. Possible mechanisms for some of these eliminations are suggested after consideration of the + E spectra of non-decomposing [M?H2O]- ions. A characteristic cyclization/retro process of o-O2NC6H4-CH=CH-C(NOH)R molecular anions produces CHO-CR=N-O- as the major product anion.

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