Gas-Phase Reaction of Acetaldehyde with Silicon-Containing Ions

2001 ◽  
Vol 7 (4-5) ◽  
pp. 343-349 ◽  
Author(s):  
D. Leblanc ◽  
J.P. Denhez ◽  
H.E. Audier
Keyword(s):  
Gas Phase ◽  
Carbonyl Compounds ◽  
Cyclotron Resonance ◽  
External Source ◽  
General View ◽  
Ion Cyclotron Resonance ◽  
Phase Reaction ◽  
Methyl Group ◽  
Gas Phase Reaction ◽  
Ft Icr

CH2=Si(CH3)OSi(CH3)2+ ions 1 were formed in the external source of a Fourier-transform ion cyclotron resonance (FT-ICR)mass spectrometer by fragmentation of (CH)3SiOSi(CH3)3. In the cell, their reactions with acetaldehyde were studied by using labeled reactants and compared with those with acetone, studied in previous work, which gives a general view of the reactions of ion 1 with carbonyl compounds. In contrast with the behavior of the corresponding carbon-containing ions, the results confirm facile 1,3-methyl group transfers from silicon to silicon. Otherwise, the silicon-containing adducts often eliminate C nH2 n. This process, not observed in (C,O,H)-containing ions, is studied by using selectively deuterated reactants.

Fourier transform ion cyclotron resonance study of the gas-phase reaction of the yttrium ion with silane

1989 ◽  
Vol 3 (9) ◽  
pp. 298-299 ◽  
Author(s):  
M. Decouzon ◽  
J-F. Gal ◽  
S. Géribaldi ◽  
M. Rouillard ◽  
J-M. Sturla ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Gas Phase ◽  
Cyclotron Resonance ◽  
Ion Cyclotron Resonance ◽  
Phase Reaction ◽  
Gas Phase Reaction ◽  
Ion Cyclotron ◽  
Yttrium Ion

Electron impact studies. LXXXVIII. formation of an adduct between the trifluoroacetate anion and perfluoroacetic anhydride by ion cyclotron resonance

1974 ◽  
Vol 27 (9) ◽  
pp. 1923 ◽  
Author(s):  
JH Bowie ◽  
BD Williams
Keyword(s):  
Gas Phase ◽  
Electron Impact ◽  
Direct Observation ◽  
Cyclotron Resonance ◽  
Ion Cyclotron Resonance ◽  
Phase Reaction ◽  
Gas Phase Reaction ◽  
Tetrahedral Intermediate ◽  
Impact Studies ◽  
Association Complex

The gas phase reaction between the trifluoroacetate anion and perfluoroacetic anhydride produces a 1 : 1 adduct. The decompositions of this adduct suggest a tetrahedral species rather than a loose association complex. If this is so, this constitutes the first direct observation of the formation of a tetrahedral intermediate produced by anionic displacement at a carbonyl centre.

Electron impact studies. XCVII. Acetic anhydride[α,α'-D2]. Synthesis and negative ion molecule reactions. An ion cyclotron resonance study

1975 ◽  
Vol 28 (9) ◽  
pp. 1993 ◽  
Author(s):  
JC Wilson ◽  
JH Bowie
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Gas Phase ◽  
Cyclotron Resonance ◽  
Negative Ion ◽  
Ion Cyclotron Resonance ◽  
Acetate Anion ◽  
Phase Reaction ◽  
Gas Phase Reaction ◽  
Ion Molecule Reactions

Acetic anhydride[α,α?-D2] has been synthesized in near-quantitative yield by the reaction between acetic acid[α-D] and dicyclohexylcarbodiimide. The gas-phase reaction between the acetate anion and acetic anhydride[α,α-D2] yields a 1 : 1 adduct which decomposes by loss of CH2CO and CHDCO so that kH/kD is 1.2 when the ion- transit time is 10-3-10-4 s, and 2.0 at 10-1-10-2 s.

Electron impact studies. LXXXIX. Nucleophilic substitution at carbonyl centres. Acetic anhydride. An ion cyclotron resonance study

1975 ◽  
Vol 28 (3) ◽  
pp. 559 ◽  
Author(s):  
JH Bowie
Keyword(s):  
Electron Beam ◽  
Acetic Anhydride ◽  
Nucleophilic Substitution ◽  
Gas Phase ◽  
Cyclotron Resonance ◽  
Ion Cyclotron Resonance ◽  
Acetate Anion ◽  
Phase Reaction ◽  
Gas Phase Reaction ◽  
Sample Pressure

The gas phase reaction between the acetate anion and acetic anhydride yields a 1 : 1 adduct, which may decompose by loss of ketene. The extent of these reactions depend upon both the sample pressure and the transit time of ions in the cell. Power absorption maxima are obtained for electron beam energies of 0 eV, 4 eV and values in excess of 10 eV.

Gas phase chemistry of α-thio carbanions

1984 ◽  
Vol 62 (11) ◽  
pp. 2273-2281 ◽  
Author(s):  
Steen Ingemann ◽  
Nico M. M. Nibbering
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Cyclotron Resonance ◽  
Ion Cyclotron Resonance ◽  
Proton Abstraction ◽  
Methyl Group ◽  
Gas Phase Chemistry ◽  
Gas Phase Acidity ◽  
Phase Chemistry ◽  
Ft Icr

Proton abstraction from CH3SCH3 and C6H5SCH3 in the gas phase has been studied by the use of Fourier Transform Ion Cyclotron Resonance (FT-ICR) mass spectrometry. The gas phase acidity of CH3SCH3 is reported to be [Formula: see text]. The methyl group in C6H5SCH3 is observed to be the most acidic position. The gas phase acidity of this group is determined to be [Formula: see text]. The structure and reactivity of the [M – H]− ions from CH3SCH3 and C6H5SCH3 are probed by studying their reactions with various molecules. Rate constants are reported for the reactions of CH3SCH2− – and several other nucleophiles – with CH3Cl, CH3Br, and HCO2CH3.

Gas-Phase Acidities of Cycloheptatrienes: Effects of Alkyl Groups on the Stability of Carbanions

2002 ◽  
Vol 8 (5) ◽  
pp. 359-366 ◽  
Author(s):  
Masaaki Mishima ◽  
Tomomi Kinoshita ◽  
Yoshitaka Hattori ◽  
Ken'ichi Takeuchi
Keyword(s):  
Mass Spectrometry ◽  
Fourier Transform ◽  
Gas Phase ◽  
Cyclotron Resonance ◽  
Ion Cyclotron Resonance ◽  
Charge Delocalization ◽  
Alkyl Groups ◽  
Respective Parent ◽  
The Stability ◽  
Ft Icr

The gas-phase acidities of 7-alkyl substituted cycloheptatrienes have been determined by Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry using a proton-transfer equilibrium method, Δ G0acid (kJ mol−1): methyl 1520.0, ethyl 1516.7, n-propyl acid 1513.3, i-propyl 1512.1, n-butyl 1510.4. The effect of alkyl groups on the acidity of cycloheptatriene is linearly correlated with the polarizability parameters ( σα) of substituents, giving a ρα of–55.3 (kJ σ−1α unit). The magnitude of pa is half of that for RCH3 and is significantly larger than that for the fluorene series. These results suggest that the extent of the charge-delocalization in a carbanion plays an important role in determining the susceptibility of the stability of the carbanion to substituent polarizability effects. In addition, comparison of ρ values of acidities of a series of elemental hydrides shows that the numerical value of ρα decreases in the order, C > O ≈ N > S, and that the change of ρα is related to the stability of the respective parent anions (R = H) rather than the atomic electronegativity at the deprotonation center.

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