Bonn 2025 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 1: Chirality
MO 1.3: Vortrag
Montag, 10. März 2025, 11:45–12:00, HS XVI
Chiral Selector Ion Vibrational Spectroscopy on Amino Acid Enantiomers — •Francine Horn1, Sonja Schmahl2, Jiaye Jin2, and Knut R. Asmis2 — 1Leipzig University / Fritz Haber Institute — 2Leipzig University
The stereochemistry and conformational flexibility of chiral molecules have a strong impact on their biochemical, and pharmacological properties. A central analytical challenge is the generally applicable differentiation of enantiomers, as well as the fast and accurate determination of the enantiomeric excess. Gas phase vibrational action spectroscopy is a highly sensitive, selective, and fast tool for this purpose.
Chiral ionic analytes are transferred into the gas phase, where they interact with volatile chiral selector molecules under the formation of diastereomeric complexes. These are then mass-selected, cryogenically cooled, messenger-tagged and an infrared photodissociation (IRPD) spectrum is measured. The spectra of the vibrationally cold diastereomers exhibit sufficiently different IR fingerprints, such that they can be spectrally distinguished and quantified.
Different intermolecular non-covalent interactions can be present in diastereomers, among them H-bonds, π-π interactions and steric hindrance. We study a set of different chiral selector molecules and chiral amino acid analytes with different structural motifs to identify the decisive interactions in the present complexes. We aim at maximizing the differences in the vibrational action spectra of the diastereomers and gain insights into the interactions governing chiral recognition by characterizing the molecular level forces at work.
Keywords: chiral; IR action spectroscopy; enantiomeric excess; gas phase; intermolecular interactions