Speaker
Description
The stereochemistry and conformational flexibility of chiral molecules have a strong impact on their biological, 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 of a chiral sample.
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 in a gas-filled ion guide 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.
