CHARACTERIZATION OF INTERMOLECULAR INTERACTIONS AT PLAY IN THE 2,2,2-TRIFLUOROETHANOL TRIMERS USING CAVITY AND CHIRPED-PULSE MICROWAVE SPECTROSCOPY

Seifert, Nathan A.

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https://hdl.handle.net/2142/97114 Copy

Description

Title

CHARACTERIZATION OF INTERMOLECULAR INTERACTIONS AT PLAY IN THE 2,2,2-TRIFLUOROETHANOL TRIMERS USING CAVITY AND CHIRPED-PULSE MICROWAVE SPECTROSCOPY

Author(s)

Seifert, Nathan A.

Contributor(s)

• Xu, Yunjie
• Jäger, Wolfgang
• Thomas, Javix

Issue Date

6/22/2017

Keyword(s)

Mini-symposium: Chirality-Sensitive Spectroscopy

Abstract

2,2,2-trifluoroethanol (TFE) is a common aqueous co-solvent in biological chemistry which may induce or destabilize secondary structures of proteins and polypeptides, thanks to its diverse intermolecular linkages originating from the hydrogen bonding potential of both the hydroxyl and perfluoro groups.footnote{M. Buck, Q. Rev. Biophys. 1998, 31, 297-335.} Theoretically, the TFE monomer is predicted to have two stable textit{gauche} (textit{gauche}$^{+}$/textit{gauche}$^{-}$) conformations whereas the textit{trans} form is unstable or is supported only by a very shallow potential. Only the gauche conformers have been identified in the gas phase, whereas liquid phase studies suggest a textit{trans}:textit{gauche} ratio of 2:3.footnote{I. Bakó, T. Radnai, M. Claire, B. Funel, J. Chem. Phys. 2004, 121, 12472-12480. } The question at which sample (cluster) size the textit{trans} form of TFE would appear was one major motivation for our study.\_x000d_ _x000d_ Here, we report the detection of three trimers of TFE using Balle-Flygare cavity and chirped-pulse Fourier transform microwave spectroscopy (CP-FTMW) techniques. The most stable observed trimer features one textit{trans}- and two textit{gauche}-TFE subunits. The other two trimers, observed using a newly constructed 2-6 GHz CP-FTMW spectrometer, consist of only the two textit{gauche} conformers of TFE. Quantum Theory of Atoms in Molecules (QTAIM)footnote{R. F. W. Bader, Chem. Rev. 1991, 91, 893-928.} and non-covalent interactions (NCI)footnote{E. R. Johnson, S. Keinan, P. Mori-Sánchez, J. Contreras-Garcia, A. J. Cohen, W. Yang, J. Am. Chem. Soc., 2010, 132, 6498-6506.} analyses give detailed insights into which intermolecular interactions are at play to stabilize the textit{trans} form of TFE in the most stable trimer.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

Permalink

http://hdl.handle.net/2142/97114

DOI

10.15278/isms.2017.RG06

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