Structure Determination, Conformational Flexibility, Internal Dynamics, and Chiral Analysis of Pulegone and Its Complex with Water.

Autor: Krin A; Deutsches Elektronen-Synchrotron, Notkestrasse 85, 22607, Hamburg, Germany.; Max-Planck Institut für Struktur und Dynamik der Materie, Luruper Chaussee 149, 22761, Hamburg, Germany.; Christian-Albrechts-Universität zu Kiel, Institute of Physical Chemistry, Max-Eyth-Str. 1, 24118, Kiel, Germany., Pérez C; Deutsches Elektronen-Synchrotron, Notkestrasse 85, 22607, Hamburg, Germany.; Max-Planck Institut für Struktur und Dynamik der Materie, Luruper Chaussee 149, 22761, Hamburg, Germany.; Christian-Albrechts-Universität zu Kiel, Institute of Physical Chemistry, Max-Eyth-Str. 1, 24118, Kiel, Germany., Pinacho P; Departamento de Química Física y Química Inorgánica, Universidad de Valladolid, Paseo Belen 7, 47011, Valladolid, Spain., Quesada-Moreno MM; Departamento de Química Física y Analítica, Universidad de Jaén, Campus Las Lagunillas, E-23071, Jaen, Spain., López-González JJ; Departamento de Química Física y Analítica, Universidad de Jaén, Campus Las Lagunillas, E-23071, Jaen, Spain., Avilés-Moreno JR; Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide Sevilla, Carretera de Utrera Km 1, E-41013, Seville, Spain., Blanco S; Departamento de Química Física y Química Inorgánica, Universidad de Valladolid, Paseo Belen 7, 47011, Valladolid, Spain., López JC; Departamento de Química Física y Química Inorgánica, Universidad de Valladolid, Paseo Belen 7, 47011, Valladolid, Spain., Schnell M; Deutsches Elektronen-Synchrotron, Notkestrasse 85, 22607, Hamburg, Germany.; Max-Planck Institut für Struktur und Dynamik der Materie, Luruper Chaussee 149, 22761, Hamburg, Germany.; Christian-Albrechts-Universität zu Kiel, Institute of Physical Chemistry, Max-Eyth-Str. 1, 24118, Kiel, Germany.
Jazyk: angličtina
Zdroj: Chemistry (Weinheim an der Bergstrasse, Germany) [Chemistry] 2018 Jan 12; Vol. 24 (3), pp. 721-729. Date of Electronic Publication: 2017 Dec 06.
DOI: 10.1002/chem.201704644
Abstrakt: In the current work we present a detailed analysis of the chiral molecule pulegone, which is a constituent of essential oils, using broadband rotational spectroscopy. Two conformers are observed under the cold conditions of a molecular jet. We report an accurate experimentally determined structure for the lowest energy conformer. For both conformers, a characteristic splitting pattern is observed in the spectrum, resulting from the internal rotation of the two non-equivalent methyl groups situated in the isopropylidene side chain. The determined energy barriers are 1.961911(46) kJ mol -1 and 6.3617(12) kJ mol -1 for one conformer, and 1.96094(74) kJ mol -1 and 6.705(44) kJ mol -1 for the other one. Moreover, a cluster of the lowest energy conformer with one water molecule is reported. The water molecule locks one of the methyl groups by means of a hydrogen bond and some secondary interactions, so that we only observe internal rotation splittings from the other methyl group with an internal rotation barrier of 2.01013(38) kJ mol -1 . Additionally, the chirality-sensitive microwave three-wave mixing technique is applied for the differentiation between the enantiomers, which can become of further use for the analysis of essential oils.
(© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)
Databáze: MEDLINE
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