Dresden 2011 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 1: Biomolecules
MO 1.6: Vortrag
Montag, 14. März 2011, 11:45–12:00, TOE 317
IR spectra of microhydrated acetanilide cluster cations — •Matthias Schmies1, Alexander Patzer1, Kohei Tanabe2, Mitsuhiko Miyazaki2, Masaaki Fujii2, and Otto Dopfer1 — 1Optik und Atomare Physik, TU Berlin, Germany — 2Chemical Resources Laboratory, Tokyo Institute of Technology, Japan
Acetanilide is one of the simplest aromatic molecules featuring a -NH-CO- peptide bond. We present IR photodissociation spectra of mass-selected complexes of the acetanilide cation microsolvated by a controlled number of ligands (L=argon, molecular nitrogen, and water). The IR spectra are analyzed by comparison with DFT calculations (M06-2X/aug-cc-pVTZ) and provide detailed information about the interaction potential (ligand binding site and interaction energy) between this prototypical biomolecular building block and polar/nonpolar ligands. Whereas Ar and molecular nitrogen preferentially bind to the aromatic ring, water exhibits hydrogen bonding to the acidic NH group of the amide moiety. The current work shows that ionization of acetanilide has a large effect on its charge distribution and its interaction with hydrophilic and hydrophobic ligands. In particular, the hydration environment is largely affected by the change in the charge distribution.