Protonation thermochemistry of selected hydroxy- and methoxycarbonyl molecules.
The gas-phase basicities of a representative set of hydroxy- and methoxycarbonyl compounds (hydroxyacetone, 1, 3-hydroxybutanone, 2, 3-hydroxy-3-methylbutanone, 3, 1-hydroxy-2-butanone, 4, 4-hydroxy-2-butanone, 5, 5-hydroxy-2-pentanone, 6, methoxyacetone, 7, 3-methoxy-2-butanone, 8, 4-methoxy-2-butanone, 9, and 5-methoxy-2-pentanone, 10) were experimentally determined by the equilibrium method using Fourier transform ion cyclotron resonance and high-pressure mass spectrometry techniques. The latter method allows the measurement of proton transfer equilibrium constants at various temperatures and thus the estimate of both the proton affinities and the protonation entropies of the relevant species. Quantum chemical calculations at the G3 and the B3LYP/6-311+G(3df,2p)//6-31G(d) levels of theory were undertaken in order to find the most stable structures of the neutrals 1-10 and their protonated forms. Conformational and vibrational analyses have been done with the aim of obtaining a theoretical estimate of the protonation entropies.
Bouchoux
Guy
G
Laboratoire des Mécanismes Réactionnels, UMR CNRS 7651, Ecole Polytechnique, 91128 Palaiseau Cedex, France.
Leblanc
Danielle
D
Bertrand
William
W
McMahon
Terance B
TB
Szulejko
Jan E
JE
Berruyer-Penaud
Florence
F
Mó
Otilia
O
Yáñez
Manuel
M
D000096:Acetone / Q000031:analogs & derivatives* / Q000737:chemistry*; D002074:Butanones / Q000737:chemistry*; D005740:Gases; D015394:Molecular Structure; D044367:Phase Transition; D011522:Protons; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics
D002074:Butanones; D005740:Gases; D011522:Protons; D000096:Acetone; C487002:1-hydroxy-2-butanone