Hannover 2016 – scientific programme

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MO: Fachverband Molekülphysik

MO 9: Biomolecules and Photochemistry

MO 9.4: Talk

Tuesday, March 1, 2016, 15:30–15:45, f102

High-resolution study of the smallest sugar dimer: Interplay of hydrogen bonds in the glycolaldehyde dimer — •Sabrina Zinn^1,2,3, Chris Medcraft¹, Thomas Betz¹, and Melanie Schnell^1,2,3 — ¹Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany — ²Center for Free-Electron Laser Science, Hamburg, Germany — ³The Hamburg Centre for Ultrafast Imaging, Hamburg, Germany

The aggregation of glycolaldehyde was studied in a conformer-selective manner using high-resolution rotational spectroscopy in the gas-phase. Glycolaldehyde is formally the smallest sugar molecule, as it contains an aldehyde- and a hydroxy-group and was the first and so far the only sugar found in space. On this model system, we reveal hydrogen bond selectivity that guides the molecular recognition of carbohydrates in nature, in agreement with previous FTIR measurements.

In the high-resolution spectrum we assigned the rotational spectra of two stable dimer conformers. The lowest energy conformer reveals C₂ symmetry by forming two intermolecular hydrogen bonds and by giving up the rather strong intramolecular hydrogen bond. In addition, we assigned all of its singly ¹³C- and ¹⁸O- substituted species in natural abundance allowing us to determine the precise structure of this conformer. Predicting a precise structure of a weakly bound complex using quantum chemical calculations is still challenging, even for a small complex like the glycolaldehyde dimer. That is why an experimentally determination of the structure is highly important to get precise information about the interplay of intermolecular interactions.