NitrileN-Selenide (RC⋮NSe) and Isoselenocyanate (RNCSe) Neutrals and Radical Cations by Selenation of Nitriles and Isonitriles:  Tandem Mass Spectrometry and ab Initio Studies

1998 ◽  
Vol 102 (45) ◽  
pp. 9021-9030 ◽  
Author(s):  
Pascal Gerbaux ◽  
Robert Flammang ◽  
Eva H. Mørkved ◽  
Ming Wah Wong ◽  
Curt Wentrup
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Ab Initio ◽  
Radical Cations ◽  
Tandem Mass

Iminoethenone Radical Cations (RN=C=C=O.cntdot.+): Tandem Mass Spectrometry and ab Initio MO Studies

1994 ◽  
Vol 98 (23) ◽  
pp. 5801-5806 ◽  
Author(s):  
Robert Flammang ◽  
Yves Van Haverbeke ◽  
Sophie Laurent ◽  
Monique Barbieux-Flammang ◽  
Ming Wah Wong ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Ab Initio ◽  
Radical Cations ◽  
Tandem Mass ◽  
Ab Initio Mo

ChemInform Abstract: Iminoethenone Radical Cations (RN=C=C=O×+): Tandem Mass Spectrometry and ab initio MO Studies

ChemInform ◽  
2010 ◽  
Vol 25 (44) ◽  
pp. no-no
Author(s):  
R. FLAMMANG ◽  
Y. VAN HAVERBEKE ◽  
S. LAURENT ◽  
M. BARBIEUX-FLAMMANG ◽  
M. W. WONG ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Ab Initio ◽  
Radical Cations ◽  
Tandem Mass ◽  
Ab Initio Mo

Generation of NitrileN-Sulfide (RCNS) Radical Cations and Neutrals via Ion−Molecule Reactions:  Tandem Mass Spectrometry and ab Initio MO Study

1997 ◽  
Vol 101 (37) ◽  
pp. 6970-6975 ◽  
Author(s):  
Pascal Gerbaux ◽  
Yves Van Haverbeke ◽  
Robert Flammang ◽  
Ming Wah Wong ◽  
Curt Wentrup
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Ab Initio ◽  
Radical Cations ◽  
Tandem Mass ◽  
Ion Molecule Reactions ◽  
Ab Initio Mo

Characterization of New Cumulenes C2NX2(X = O or S):  Tandem Mass Spectrometry and ab Initio Studies

1996 ◽  
Vol 100 (25) ◽  
pp. 10536-10541 ◽  
Author(s):  
Ming Wah Wong ◽  
Curt Wentrup ◽  
Eva H. Mørkved ◽  
Robert Flammang
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Ab Initio ◽  
Tandem Mass

The decarbonylation of ionized β-hydroxypyruvic acid: the hydrogen-bridged radical cation [CH2=O . . .H . . .==C-OH].+ studied by experiment and theory

1998 ◽  
Vol 76 (3) ◽  
pp. 335-349 ◽  
Author(s):  
Lorne M Fell ◽  
Peter C Burgers ◽  
Paul JA Ruttink ◽  
Johan K Terlouw
Keyword(s):  
Mass Spectrometry ◽  
Methyl Ester ◽  
Tandem Mass Spectrometry ◽  
Ab Initio ◽  
Radical Cation ◽  
Glycolic Acid ◽  
High Energy ◽  
Low Energy ◽  
Tandem Mass ◽  
Low Energy Ions

The intriguing gas-phase ion chemistry of β-hydroxypyruvic acid (HPA), HOCH2C(==O)COOH, has been investigated using tandem mass spectrometry (metastable ion (MI) and (multiple) collision-induced dissociation (CID) experiments, neutralization-reionization mass spectrometry (NRMS), 18O and D isotopic labelling on both the acid and its methyl ester) in conjunction with computational chemistry (ab initio MO and density functional theories). HPA does not enolize upon evaporation, but it retains its keto structure. When ionized, decarbonylation occurs and, depending on the internal-energy content, this dissociation reaction proceeds via two distinct routes. The source-generated, high-energy ions lose the keto C==O, not via a least-motion extrusion into ionized glycolic acid, HOCH2COOH.+ , but via a rearrangement that yields the title H-bridged radical cation CH2==O ... H ... O==C-OH.+ for which Δ Hf0 = 99 ± 3 kcal/mol. The long-lived low-energy ions enolize prior to decarbonylation and lose the carboxyl C==O. Again, this is not a least-motion extrusion (which would produce the most stable isomer, HOC(H)==C(OH)2.+ Δ Hf0 = 73 kcal/mol) but a rearrangement yielding the ion-dipole complex HOC(H)C==C==O.+/H2O. The methyl ester of HPA behaves analogously, yielding CH2==O... H ...O==C-OCH3.+ and HOC(H)C==C==O.+ / CH3OH upon decarbonylation of the high- and low-energy ions, respectively. Decarboxylation into the ylidion CH2OH2.+ characterizes the dissociation chemistry of both the title H-bridged ion and its glycolic acid isomer HOCH2COOH.+ . A computational analysis of this reaction (which satisfies the experimental observations) leads to the proposal that the decarboxylation of the acid occurs via CH2-O(H) ... H ... ==C==O.+ as the key intermediate, whereas the title H-bridged ion follows a higher energy route that involves ion-dipole rotations leading to the ionized carbene HO(H2)CO-C-OH.+ and the distonic ion H2O-C(H2)-O-C==O.+ as key intermediates.Key words: tandem mass spectrometry, hydrogen-bridged radical cation, hydroxypyruvic acid, ab initio calculations, keto-enol tautomerization, 18O labelling.

Polycarbon Disulfides SCnS (n = 1-3) and Their Protonated and Methylated Forms (HCnS2+ and CH3CnS2+): Tandem Mass Spectrometry and ab Initio MO Study

1995 ◽  
Vol 99 (46) ◽  
pp. 16849-16856 ◽  
Author(s):  
Ming Wah Wong ◽  
Curt Wentrup ◽  
Robert Flammang
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Ab Initio ◽  
Tandem Mass ◽  
Ab Initio Mo

Characterization of [C6H7N]+˙ radical cations by tandem mass spectrometry

1992 ◽  
Vol 6 (2) ◽  
pp. 135-139 ◽  
Author(s):  
Robert Flammang ◽  
Olivier Thoelen ◽  
Calogero Quattrocchi ◽  
Jean-Luc Bredas
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Radical Cations ◽  
Tandem Mass
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