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.

Electron impact studies. CVII—Negative ion mass spectra of the oxime group. Monoximes derived from α-dicarbonyl systems

1976 ◽  
Vol 11 (12) ◽  
pp. 1290-1296 ◽  
Author(s):  
John H. Bowie ◽  
Sompong Janposri
Keyword(s):  
Electron Impact ◽  
Mass Spectra ◽  
Negative Ion ◽  
Oxime Group ◽  
Impact Studies

Electron impact studies. XCVIII. Negative ion mass spectra of the carbonyl group. The Aryl-CO- and Aryl-COCO- systems

1975 ◽  
Vol 28 (10) ◽  
pp. 2169 ◽  
Author(s):  
JH Bowie ◽  
S Janposri
Keyword(s):  
Nitro Group ◽  
Electron Impact ◽  
General Formula ◽  
Carbonyl Group ◽  
Mass Spectra ◽  
Negative Ion ◽  
Aryl Group ◽  
Impact Studies ◽  
Molecular Anions

Collision-induced decompositions of molecular anions of the general formula aryl-CO-alkyl yield aryl- ions. The aryl-CO-aryl group is stable under these conditions. Parent anions from α-dicarbonyl systems do not generally fragment but, in the case of o-nitrobenzil, fragment anions are produced after cyclization of the nitro group at both carbonyl centres.

Electron impact studies. XCVI. Negative ion mass spectra of naturally occurring compounds. Nitrophenyl esters derived from long-chain acids andalcohols

1975 ◽  
Vol 28 (5) ◽  
pp. 1011 ◽  
Author(s):  
JH Bowie ◽  
BJ Stapleton
Keyword(s):  
Electron Impact ◽  
Analytical Method ◽  
Mass Spectra ◽  
Molecular Ions ◽  
Negative Ion ◽  
Impact Studies ◽  
Naturally Occurring ◽  
Molecular Anions ◽  
Positive Ion ◽  
Long Chain

The positive ion mass spectra of long-chain alcohols and acids are either devoid of molecular ions or contain such species in low abundance. The negative ion spectra of p-nitrophenyl esters of these compounds exhibit pronounced molecular anions, showing the technique to be a useful analytical method for these classes of compounds.

Electron impact studies. CI—negative ion mass spectra of the carbonyl group. The ArylCH2CO- and Aryl(CH2)2CO- systems

1975 ◽  
Vol 10 (12) ◽  
pp. 1117-1124 ◽  
Author(s):  
John H. Bowie ◽  
Sompong Janposri
Keyword(s):  
Electron Impact ◽  
Carbonyl Group ◽  
Mass Spectra ◽  
Negative Ion ◽  
Impact Studies

Electron impact studies. CXXV. Negative ion mass spectra of thiobenzamides. Dual mechanisms for loss of NO∓ from o-nitrothiobenzamides

1979 ◽  
Vol 29 (3) ◽  
pp. 223-230 ◽  
Author(s):  
K. Clausen ◽  
B.S. Pedersen ◽  
S. Scheibye ◽  
S.-O. Lawesson ◽  
J.H. Bowie
Keyword(s):  
Electron Impact ◽  
Mass Spectra ◽  
Negative Ion ◽  
Impact Studies

Electron impact studies. CXXIV—Negative ion mass spectra of organic functional groups. Thioacetanilides

1979 ◽  
Vol 14 (2) ◽  
pp. 101-103 ◽  
Author(s):  
K. Clausen ◽  
B. S. Pedersen ◽  
S. Scheibye ◽  
S.-O. Lawesson ◽  
J. H. Bowie
Keyword(s):  
Electron Impact ◽  
Functional Groups ◽  
Mass Spectra ◽  
Negative Ion ◽  
Impact Studies ◽  
Organic Functional Groups

Electron impact studies. CXV. Release of kinetic energy during negative ion decompositions. C-O bond cleavage reactions

1977 ◽  
Vol 30 (6) ◽  
pp. 1249 ◽  
Author(s):  
G Klass ◽  
JH Bowie
Keyword(s):  
Kinetic Energy ◽  
Energy Release ◽  
Electron Impact ◽  
Bond Cleavage ◽  
Kinetic Energy Release ◽  
Negative Ion ◽  
Impact Studies ◽  
Molecular Anions ◽  
Cleavage Reactions

Kinetic energy release values T(50%) for the collision-induced formation of the p-nitrobenzoate and p-nitrophenoxide anions from the molecular anions of p-O2NC6H4COOC6H4R-p and p-O2NC6H4- OC6H4R-p respectively are small and relatively insensitive to the nature of the substituent R.T (50%) values for the elimination of R? (R = alkyl) from O2NC6H4OR molecular anions range from 0.4 to 0.01 eV, and are dependent upon the nature of R and upon its number of active oscillators.

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