Gas phase basicity of dihydropyran and dihydro-1,4-dioxin

1986 ◽  
Vol 64 (7) ◽  
pp. 1295-1297 ◽  
Author(s):  
G. Bouchoux ◽  
I. Hanna ◽  
R. Houriet ◽  
E. Rolli
Keyword(s):  
Double Bond ◽  
Proton Transfer ◽  
Gas Phase ◽  
Molecular Orbital ◽  
Cyclotron Resonance ◽  
Transfer Reactions ◽  
Molecular Orbital Calculations ◽  
Ion Cyclotron Resonance ◽  
Lower Reactivity ◽  
Proton Transfer Reactions

The gas phase basicity (GB) of dihydropyran 1 and dihydro-1,4-dioxin 2 is measured in equilibrium proton transfer reactions conducted in an ion cyclotron resonance spectrometer. GB(1) is found to be greater than GB(2) by 37 kJ mol−1, this difference parallels the lower reactivity of 2 observed in solution under acidic condition. Conclusion as to the favoured protonation of the C—C double bond, giving rise for both 1 and 2 to oxycarbonium cations, is drawn from comparison with analogous compounds and substantiated by molecular orbital calculations (MNDO) on the protonated structures.

Gas-Phase Basicity of Formaldehyde by the Thermokinetic Method

2000 ◽  
Vol 6 (2) ◽  
pp. 109-112 ◽  
Author(s):  
Guy Bouchoux ◽  
Danielle Leblanc
Keyword(s):  
Fourier Transform ◽  
Proton Transfer ◽  
Equilibrium Constant ◽  
Gas Phase ◽  
Cyclotron Resonance ◽  
Transfer Reactions ◽  
Ion Cyclotron Resonance ◽  
Proton Transfer Reactions ◽  
Ft Icr

A series of proton transfer reactions monitored in a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer allows the determination of the gas-phase basicity ( GB) and the proton affinity ( PA) of formaldehyde. The values determined by the thermokinetic method, GB(CH2O) = 681.5 ± 0.7 kJ mol−1 and PA(CH2O) = 711.5 ± 2.1 kJ mol−1 are in excellent agreement with data originating from proton transfer equilibrium constant determinations or from G2 calculations.

Gas-phase proton-transfer reactions of the hydronium ion at 298 K

1979 ◽  
Vol 57 (12) ◽  
pp. 1518-1523 ◽  
Author(s):  
Gervase I. Mackay ◽  
Scott D. Tanner ◽  
Alan C. Hopkinson ◽  
Diethard K. Bohme
Keyword(s):  
Proton Transfer ◽  
Gas Phase ◽  
Rate Constants ◽  
Transfer Reactions ◽  
Flowing Afterglow ◽  
Hydronium Ion ◽  
Proton Transfer Reactions

Rate constants measured with the flowing afterglow technique at 298 ± 2 K are reported for the proton-transfer reactions of H3O+ with CH2O, CH3CHO, (CH3)2CO, HCOOH, CH3COOH, HCOOCH3, CH3OH, C2H5OH, (CH3)2O, and CH2CO. Dissociative proton-transfer was observed only with CH3COOH. The rate constants are compared with the predictions of various theories for ion–molecule collisions. The protonation is discussed in terms of the energetics and mechanisms of various modes of dissociation.

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