title: A peptide co-solvent under scrutiny: self-aggregation of 2,2,2-trifluoroethanol.
abstract: Trifluoroethanol (TFE) and its aggregates are studied via supersonic jet FTIR and Raman spectroscopy as well as by quantum chemistry and simple force field approaches. A multi-slit nozzle is introduced to study collisionally excited clusters. Efforts are made to extract harmonic frequencies from experiment for better comparison to theory. Based on deuteration, the OH stretching anharmonicity changes weakly upon dimerization, but increases for trimers. Among the possible dimer conformations, only an all-gauche, homoconfigurational, compact, OH-F connected structure is observed in an extreme case of chiral discrimination. Quantum tunneling assisted pathways for this surprising helicity synchronization are postulated. The oscillator coupling in hydrogen-bonded trimers is analyzed. Trans conformations of TFE start to become important for trimers and probably persist in the liquid state. Simple force fields can be refined to capture some molecular recognition features of TFE dimer, but their limitations are emphasized.
authors: Institut für Physikalische Chemie, Universität Göttingen, Tammannstr. 6, 37077, Göttingen, Germany.
authors: Tina
authors: T
authors: Scharge
authors: Christine
authors: C
authors: Cézard
authors: Philipp
authors: P
authors: Zielke
authors: Anne
authors: A
authors: Schütz
authors: Corinna
authors: C
authors: Emmeluth
authors: Martin A
authors: MA
authors: Suhm
mesh_terms: D019281:Dimerization; D006860:Hydrogen Bonding; D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation; D011789:Quantum Theory; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D014270:Trifluoroethanol / Q000737:chemistry*
chemical_list: D010455:Peptides; D014270:Trifluoroethanol