Publication
Conformational Dynamics of Perfluorooctanoic Acid (PFOA) Studied by Molecular Rotational Resonance (MRR) Spectroscopy
Originally published in Chemical Physics Letters, September 2021
Authors: Rebekah N. Schilberg; Suying Wei; Sylvestre Twagirayezu; Justin L. Neill
Publication Summary
Originally published in Chemical Physics Letters, this study uses molecular rotational resonance (MRR) spectroscopy to investigate the conformational dynamics of perfluorooctanoic acid (PFOA), a widely used perfluorinated compound of environmental concern. By combining broadband rotational spectroscopy with quantum chemical calculations, the researchers characterized the gas-phase structure of PFOA and examined how its flexible fluorinated carbon chain adopts different molecular conformations.
The analysis revealed six conformers of PFOA in a pulsed-jet expansion experiment. Comparison of experimental spectra with theoretical predictions showed that the perfluorinated carbon chain preferentially adopts a helical configuration that maximizes separation between fluorine atoms. The study also evaluated barriers to conformational interconversion, including pathways that reverse the direction of the molecular helix, providing new insight into the structural behavior of highly fluorinated molecules.
Key Takeaways
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Identifies and assigns six distinct conformers of PFOA in the gas phase.
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Combines MRR spectroscopy with quantum chemical calculations for conformer identification.
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Demonstrates that the fluorinated carbon chain preferentially adopts a helical structure.
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Shows that helical conformations help maximize separation between fluorine atoms.
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Evaluates conformational isomerization pathways between low-energy structures.
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Provides insight into the structural dynamics of environmentally relevant PFAS compounds.