Evidence for Gas-Phase Hydrogen-Bonded Complexes of the Form [CH3+/CH3OH] and [CH3+/CH3OCH3]

Audier, H. E.; Koyanagi, Gregory K.; McMahon, T. B.; Thölmann, Detlef

doi:10.1021/jp952174m

Cited by 25 publications

(25 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Examples include the dimethylchloronium, dimethylfluoronium and trimethyloxonium ions and protonated dimethyl ether. [85][86][87] Protonated dimethyl ether and the trimethyloxonium ion also lose methanol and dimethyl ether, respectively, to give the methyl cation. 85 The energy dependence of the collision-induced formation of the methyl cation from the trimethyloxonium cation showed that the energy needed to promote this reaction is 386 kJ mol -1 ; this energy coincides with the thermochemical threshold for formation of the products.…”

Section: Alkane Eliminations From Onium Ionsmentioning

confidence: 99%

EMS Account: Alkane eliminations from ions in the gas phase

McAdoo

Bowen

1999

Eur. J. Mass Spectrom.

View full text Add to dashboard Cite

A review of reactions involving the elimination of an alkane from a variety of even and odd electron ions in the gas phase is presented. Particular attention is focused on the mechanisms of these reactions and the role of ion-neutral complexes. Alkane eliminations from open shell species derived by ionisation of ketones, ethers, alcohols, amines, alkanes and alkyl-substituted cycloalkanes are considered, together with ethane loss from the distonic ion CH 2 =O + CH 2 CH 2 •. These reactions are, without obvious exception, complex-mediated. Elimination of alkanes from an assortment of closed shell ions, including protonated acetaldehyde, dialkylmethylene immonium ions, onium ions, quaternary ammonium cations, alkoxide anions, enolate anions and deprotonated amines are also discussed. These reactions tend to be complex-mediated when heterolytic bond cleavages are possible. When such cleavages are not energetically feasible, alkane eliminations can take place by asynchronous, concerted mechanisms. Several factors affect the relative rates of alkane elimination compared to those of competing alkyl radical loss in the dissociations of these radical-cations; these factors include the internal energy of the ion, the size of the ionic and neutral partners, the initial orientation of these components and the binding energy of the complex. In addition, primary and secondary isotope effects influence both alkyl radical and alkane elimination. When alkanes are eliminated from radical-cations, reaction between the partners is often quickly overtaken in importance by direct separation of the components if the internal energy is raised either by increasing the energy of the ionisation process or by prior isomerisation over an energy barrier. This trend demonstrates that the attractions between the partners are easily overcome by quite small amounts of excess energy in the system. Typical binding energies between the ionic and non-polar neutral partners lie in the range 0-30 kJ mol-1 at distances at which covalent forces cease to be significant. Illustrative examples are given to show how studies of reactions involving ion-neutral complexes offer a means of obtaining information on the dynamics of short range interactions between ions and neutrals, including the motions of the partners relative to each other.

show abstract

Section: Alkane Eliminations From Onium Ionsmentioning

confidence: 99%

EMS Account: Alkane eliminations from ions in the gas phase

McAdoo

Bowen

1999

Eur. J. Mass Spectrom.

View full text Add to dashboard Cite

show abstract

“…Accordingly, within INC‐1, the reaction of hydride transfer from the carbon atom adjacent to the nitrogen to the benzyl cation is feasible. As a matter of fact, the hydride abstraction within a complex between the cation and the neutral partner is applied to explain many neutral loss reactions in gas phase, e.g., the loss of methane from protonated dimethyl ether …”

Section: Resultsmentioning

confidence: 99%

Fragmentation reactions of N‐benzyltetrahydroquinolines in electrospray ionization mass spectrometry: the roles of ion/neutral complex intermediates

Guo

Jiang

Zheng

2014

Rapid Comm Mass Spectrometry

View full text Add to dashboard Cite

show abstract

“…This effect is similar to what happens in conventional hydrogen bond systems. 24 On the contrary, when the hydrogen bond is formed, the charge separation in CH 2 increases and the electrostatic interaction increases. Thus, a shorter C-H bond length is obtained.…”

Section: Resultsmentioning

confidence: 99%

Computational Study on the Unconventional Hydrogen‐Bonded F–H···C Systems

Liao

2009

J Chinese Chemical Soc

View full text Add to dashboard Cite

The F-H···YZ 2 (Y = C, Si, BH, AlH; Z = H, PH 3 ) systems were examined using density functional theory calculations. The main focus of this work is to demonstrate that the chemistry of Y(PH 3 ) 2 exhibits a novel feature which is a central Y atom with unexpected high basicity. Further, the hydrogen bond strength can be adjusted by the substitution of H atoms of YH 2 by PH 3 groups. The FH···C(PH 3 ) 2 system has the strongest hydrogen bond interaction, which is larger than a conventional hydrogen bond. In addition to electrostatic interaction, donor-acceptor interaction also plays an important role in determining the hydrogen bond strength. Therefore, a carbon atom can not only be the hydrogen bond acceptor but also can create an unusual stabilized hydrogen bond complex. Also, X 3 B-YZ 2 (X = H, F; Y = C, Si, BH, AlH; Z = PH 3 , NH 3 ) systems were examined, and it was found that the bond strength is controlled predominately by the HOMO-LUMO gap (DIP). The smaller the DIP, the larger the bond dissociation energy of the B-Y bond. In addition, NH 3 is a better electron-donating group than PH 3 , and thus forms the strongest donor-acceptor interaction between X 3 B and Y(NH 3 ) 2 .

show abstract

Evidence for Gas-Phase Hydrogen-Bonded Complexes of the Form [CH₃⁺/CH₃OH] and [CH₃⁺/CH₃OCH₃]

Cited by 25 publications

References 12 publications

EMS Account: Alkane eliminations from ions in the gas phase

EMS Account: Alkane eliminations from ions in the gas phase

Fragmentation reactions of N‐benzyltetrahydroquinolines in electrospray ionization mass spectrometry: the roles of ion/neutral complex intermediates

Computational Study on the Unconventional Hydrogen‐Bonded F–H···C Systems

Contact Info

Product

Resources

About