title: Determination of thermodynamic parameters of tautomerization in gas phase by mass spectrometry and DFT calculations: Keto-enol versus nitrile-ketenimine equilibria.
abstract: The study of tautomerics equilibria is really important because the reactivity of each compound with tautomeric capacity can be determined from the proportion of each tautomer. In the present work the tautomeric equilibria in some γ,δ-unsaturated β-hydroxynitriles and γ,δ-unsaturated β-ketonitriles were studied. The first family of compounds presents two possible theoretical tautomers, nitrile and ketenimine, while the second one presents four possible theoretical tautomers, keto-nitrile, enol (E and Z)-nitrile and keto-ketenimine. The equilibrium in gas phase was studied by gas chromatography-mass spectrometry (GC-MS). Tautomerization enthalpies were calculated by this methodology, and results were compared with those obtained by density functional theory (DFT) calculations, observing a good agreement between them. Nitrile tautomers were favored within the first family of compounds, while keto-nitrile tautomers were favored in the second family.
authors.affiliation: Laboratorio de Estudio de Compuestos Orgánicos (LADECOR), Facultad de Ciencias Exactas, calle 47 y 115 S/N, UNLP, C.P. 1900, Argentina.
authors.forename: Juan M
authors.initials: JM
authors.lastname: Giussi
authors.forename: Belen
authors.initials: B
authors.lastname: Gastaca
authors.forename: Alberto
authors.initials: A
authors.lastname: Albesa
authors.forename: M Susana
authors.initials: MS
authors.lastname: Cortizo
authors.forename: Patricia E
authors.initials: PE
authors.lastname: Allegretti
mesh_terms: D000438:Alcohols / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D007097:Imines / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry*; D007700:Kinetics; D008956:Models, Chemical; D009570:Nitriles / Q000737:chemistry*; D011789:Quantum Theory; D013237:Stereoisomerism; D013816:Thermodynamics
chemical_list: D000438:Alcohols; D007097:Imines; D007659:Ketones; D009570:Nitriles