The First Nonclassical Distonic Ion

2000 ◽  
Vol 122 (32) ◽  
pp. 7776-7780 ◽  
Author(s):  
Fabio C. Gozzo ◽  
Luiz Alberto B. Moraes ◽  
Marcos N. Eberlin ◽  
Kenneth K. Laali
Keyword(s):  
Distonic Ion

Generation of the distonic ion CH2NH3.bul.+: nucleophilic substitution of the ketene cation radical by ammonia and unimolecular decarbonylation of ionized acetamide

1987 ◽  
Vol 109 (16) ◽  
pp. 4810-4818 ◽  
Author(s):  
Thomas Drewello ◽  
Nikolaus Heinrich ◽  
Wilfried P. M. Maas ◽  
Nico M. M. Nibbering ◽  
Thomas Weiske ◽  
...  
Keyword(s):  
Nucleophilic Substitution ◽  
Cation Radical ◽  
Distonic Ion

Unimolecular and Bimolecular Reactions of the .beta.-Distonic Ion CH3CH2OH+CH2CH2.bul.: An Experimental and Theoretical Study

1995 ◽  
Vol 99 (27) ◽  
pp. 10837-10846 ◽  
Author(s):  
Valerie Brenner ◽  
Arielle Milliet ◽  
Philippe Mourgues ◽  
Gilles Ohanessian ◽  
Henri-Edouard Audier
Keyword(s):  
Theoretical Study ◽  
Bimolecular Reactions ◽  
Distonic Ion

Multiple Hydrogen Shifts Leading to Ammonia Loss from the Molecular Ions of Cyanocyclohexanes

2002 ◽  
Vol 8 (6) ◽  
pp. 435-445 ◽  
Author(s):  
T.A. Molenaar-Langeveld ◽  
A.M. van der Burg ◽  
S. Ingemann
Keyword(s):  
Molecular Ions ◽  
Minor Importance ◽  
Deuterium Labeling ◽  
Ammonia Loss ◽  
Cis And Trans Isomers ◽  
Metastable Ions ◽  
Cyclohexadienyl Radical ◽  
A Minor ◽  
Cis And Trans ◽  
Distonic Ion

The loss of ammonia from the metastable molecular ions of cyclic cyano compounds has been examined with the use of deuterium labeling and tandem mass spectrometry. Loss of ammonia is significant for ionized cyanocyclohexane, 1-methyl-, 4-methyl-, 4-cyano-and 4-phenyl-cyanocyclohexanes, 4-cyanopiperidine, cyanocycloheptane and 2-cyanonorbornane. By contrast, loss of ammonia is of minor importance (or absent) for the molecular ions of cyanocyclopentane, 2-methyl-cyanocyclohexane, 1-phenyl-cyanocyclohexane, 1-cyanocyclohexene, 4-cyanotetrahydrothiopyran, 2-cyano-5-norbornene and isocyanocyclohexane. Deuterium labeling of cyanocyclohexane reveals the occurrence of an H-shift from the 4-position to the cyano function, followed by a 1,2-H shift from the 1-position to the C-atom of the newly-formed–CNH group. Subsequently, a series of H-shifts leads to a distonic ion that is formulated as an N-protonated methylamine attached to a cyclohexadienyl radical. Loss of ammonia ensues and leads to ionized toluene as indicated by collision-induced dissociation experiments. For 4-phenyl-cyanocyclohexane, the metastable ions of the cis- and trans-isomers display, essentially, the same unimolecular chemistry. Briefly, the labeling of 4-phenyl-cyanocyclohexane indicates the following: (i) the H atom at the 4-position of the cyclohexane ring is incorporated, to a minor extent, in the ammonia molecule, (ii) loss of NHD2 predominates in the reactions of the molecular ions of 2,2,6,6-d4-4-phenyl-cyanocyclohexane and (iii) the ionized 3,3,5-d3-labeled species expels mainly NH2D. In addition, the metastable molecular ions of the 4-[d5-phenyl]-cyanocyclohexane expel NH3 and NH2D in a ratio of 35:65. A mechanistic scheme is proposed that is consistent with the labeling results for 4-phenyl-cyanocyclohexane as well as the indicated formation of ionized 4-methylbiphenyl as the product ion of ammonia loss.

Bimolecular reactions involving the radical site of the distonic ion ·CH2CH2CH2CO+

1993 ◽  
Vol 7 (5) ◽  
pp. 392-399 ◽  
Author(s):  
Krista M. Stirk ◽  
Rebecca L. Smith ◽  
Joe C. Orlowski ◽  
Hilkka I. Kenttämaa
Keyword(s):  
Bimolecular Reactions ◽  
Radical Site ◽  
Distonic Ion

Gas-phase reactions of the sulphur distonic ion with alkenes

1993 ◽  
Vol 28 (8) ◽  
pp. 919-920 ◽  
Author(s):  
Margot W. van Amsterdam ◽  
Paul O. Staneke ◽  
Steen Ingemann ◽  
Nico M. M. Nibbering
Keyword(s):  
Gas Phase ◽  
Gas Phase Reactions ◽  
Distonic Ion

Differentiation of Ionised Benzimidazole from its Isomeric α-Distonic Ion by Collision-Induced Dissociation and Neutralisation—Reionisation Mass Spectrometry

2005 ◽  
Vol 11 (4) ◽  
pp. 381-387 ◽  
Author(s):  
Thanasis Karapanayiotis ◽  
Richard D. Bowen
Keyword(s):  
Mass Spectra ◽  
Radical Cations ◽  
Time Frame ◽  
Careful Consideration ◽  
Collision Induced Dissociation ◽  
Doubly Charged Ions ◽  
Doubly Charged ◽  
Ion Collision ◽  
Charged Ions ◽  
Distonic Ion

Ionised benzimidazole and its isomeric α-distonic ion (or ionised ylid) have been examined by recording their metastable ion, collision-induced dissociation and neutralisation–reionisation mass spectra. These tautomers may be distinguished by careful consideration of key features of the collision-induced dissociation spectra, with or without prior neutralisation and reionisation. Formation of doubly-charged ions by charge stripping occurs preferentially when the α-distonic ion is subjected to collision. This α-distonic ion survives neutralisation and reionisation, thus establishing that the corresponding ylid is stable on the microsecond time frame. The effects of benzannulation on the ease of differentiation of classical and distonic radical cations derived from biologically important heterocycles are considered.

Regiospecific addition of CH2O at the radical site of the˙CH2CH2OHCH3+ distonic ion

1995 ◽  
Vol 30 (12) ◽  
pp. 1747-1751 ◽  
Author(s):  
V. Troude ◽  
D. Leblanc ◽  
P. Mourgues ◽  
H. E. Audier
Keyword(s):  
Radical Site ◽  
Distonic Ion
Sign in / Sign up

Export Citation Format

Share Document