Mechanistic studies of processes involving carbon-carbon bond cleavage in gas-phase organometallic reactions using product kinetic energy release distributions: Co+ reacting with cyclopentane

The gas-phase thermal isomerizations of deuteriocyclopropane to the four possible monodeuterium-labeled propenes have been followed at 435 °C. The observed distribution of products provides estimates of two deuterium kinetic isotope effects, the secondary [Formula: see text] for the carboncarbon bond cleavage leading to trimethylene diradical reactive intermediates and the primary [Formula: see text] ratio for a [1,2] shift of a hydrogen or deuterium leading from the diradical to a labeled propene. The values determined are [Formula: see text] = 1.09 ± 0.03 and [Formula: see text] = 1.55 ± 0.06. The experimental [Formula: see text] value found agrees well with some, but not all, earlier calculated values and conjectures. Key words: cyclopropane, thermal rearrangement, kinetic isotope effects.

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Peter J Derrick and the Grand Scale ‘Magnificent Mass Machine’ mass spectrometer at Warwick

European Journal of Mass Spectrometry ◽

10.1177/1469066717737643 ◽

2017 ◽

Vol 23 (6) ◽

pp. 319-326 ◽

Cited By ~ 2

Author(s):

AW Colburn ◽

Peter J Derrick ◽

Richard D Bowen

Keyword(s):

Kinetic Energy ◽

Energy Release ◽

Gas Phase ◽

Mass Spectrometer ◽

Methyl Ether ◽

Kinetic Energy Release ◽

Neutral Complex ◽

Ethyl Radical ◽

Unpublished Work ◽

Distonic Ions

The value of the Grand Scale ‘Magnificent Mass Machine’ mass spectrometer in investigating the reactivity of ions in the gas phase is illustrated by a brief analysis of previously unpublished work on metastable ionised n-pentyl methyl ether, which loses predominantly methanol and an ethyl radical, with very minor contributions for elimination of ethane and water. Expulsion of an ethyl radical is interpreted in terms of isomerisation to ionised 3-pentyl methyl ether, via distonic ions and, possibly, an ion-neutral complex comprising ionised ethylcyclopropane and methanol. This explanation is consistent with the closely similar behaviour of the labelled analogues, C3H7CH2CD2OCH3+. and C3H7CD2CH2OCH3+., and is supported by the greater kinetic energy release associated with loss of ethane from ionised n-propyl methyl ether compared to that starting from directly generated ionised 3-pentyl methyl ether.

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Mechanistic Studies of the O2-Dependent Aliphatic Carbon−Carbon Bond Cleavage Reaction of a Nickel Enolate Complex

Inorganic Chemistry ◽

10.1021/ic1017888 ◽

2011 ◽

Vol 50 (3) ◽

pp. 1047-1057 ◽

Cited By ~ 29

Author(s):

Lisa M. Berreau ◽

Tomasz Borowski ◽

Katarzyna Grubel ◽

Caleb J. Allpress ◽

Jeffrey P. Wikstrom ◽

...

Keyword(s):

Bond Cleavage ◽

Mechanistic Studies ◽

Cleavage Reaction ◽

Carbon Bond ◽

Bond Cleavage Reaction ◽

Carbon Carbon Bond ◽

Aliphatic Carbon

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The structure and fragmentation of protonated carboxylic acids in the gas phase

Canadian Journal of Chemistry ◽

10.1139/v79-459 ◽

1979 ◽

Vol 57 (21) ◽

pp. 2827-2833 ◽

Cited By ~ 42

Author(s):

Nora E. Middlemiss ◽

Alex. G. Harrison

Keyword(s):

Kinetic Energy ◽

Energy Release ◽

Gas Phase ◽

Activation Barrier ◽

Kinetic Energy Release ◽

Drift Region ◽

Metastable Peak ◽

Butyl Esters ◽

Peak Intensity ◽

A Minor

Gaseous protonated acids fragment in the first drift region of a double focussing mass spectrometer to yield the corresponding acylium ion and water. The metastable peaks for this fragmentation reaction have been recorded for the protonated acids from acetic to valeric and the kinetic energy release distributions evaluated from the metastable peak shapes. The protonated acids were produced by dissociative ionization of the ethyl, propyl, and butyl esters. The results provide evidence for two structures for gaseous protonated acids. Fragmentation of the hydroxyl protonated structure, a minor contributor to the metastable peak intensity, shows a low kinetic energy release (T(most probable) = 0.02 eV) as would be expected for a simple bond fission reaction. Fragmentation of the carbonyl protonated acid, which represents the major part of the metastable peak, is accompanied by a muchlarger kinetic energy release (T(most probable) = 0.30 to 0.43 eV). This result is interpreted in terms of an activation barrier for fragmentation of the carbonyl protonated acid which is considerably greater than the reaction endothermicity, with the excess energy being partitioned between internal energy and kinetic energy of the fragments. The results indicate that the addition of the acylium ion to water in the gas phase to produce the carbonyl protonated acid has an activation energy barrier.

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