Project Info

*Computational Protocol to Predict NMR Parameters of Perfluoroalkyl Substances

Shubham Vyas
svyas@mines.edu
Per- and polyfluorinated alkyl substances (PFASs) are robust “forever” chemicals that have become global environmental contaminants due to their inability to degrade using traditional techniques. This has led to the regulation of two legacy PFASs in the United States: perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). A central property of all PFASs is their preference to adopt helical conformations, which may have significant implications regarding their environmental impact. Helicity is described by the rotation of CF2 units around the carbon backbone which may shield the backbone from different degradation techniques. Previous methods to characterize their helical nature involve X-ray diffraction and microwave spectroscopy. More recently, 19-Fluorine NMR has been used to detect the structure of degradation PFAS products. This work aims to develop a protocol for 19-F NMR calculations, which will allow us to establish accurate methods in replicating experimental chemical shifts. 19F NMR will help us determine the structures of cationic, anionic and zwitterionic PFASs with different chain lengths and functional groups.

More Information:

Grand Challenge: Provide access to clean water
Van Hoomissen, D. J.; Vyas, S. “Early Events in the Reduction of Perfluoroalkyl Substances” Environ. Sci. Technol. Lett. 2019, 6, 365-371. (DOI: 10.1021/acs.estlett.9b00116) Liu, J.; Van Hoomissem D. J.; Liu, T.; Maizel, A.; Huo, X.; Fernandez, S. R.; Ren, C.; Xiao, X.; Fang, Y.; Schaefer, C. E.; Higgins, C. P.; Vyas, S.; Strathmann, T. J. “Reductive Defluorination of Branched Per- and Polyfluoroalkyl Substances with Cobalt Complex Catalysts” Environ. Sci. Technol. Lett. 2018, 5, 289-294. (DOI: 10.1021/acs.estlett.8b00122) Van Hoomissen, D. J.; Vyas, S. “1,2-Fluorine Radical Rearrangements: Isomerization Events in Perfluorinated Radicals” J. Phys. Chem. A, 2017, 121, 8675-8687. (DOI: 10.1021/acs.jpca.7b08895) Motz, A. R.; Herring, A. M.; Vyas, S.; Maupin, C. M. “Quantum Mechanical Study of the Reaction Mechanism for 2π-2π Cycloaddition of Fluorinated Methylene Groups” J. Org. Chem. 2017, 82, 6578-6585. (DOI: 10.1021/acs.joc.7b00597)

Primary Contacts:

Prof. Shubham Vyas (svyas@mines.edu)

Student Preparation

Qualifications

A sophomore or a junior level student. Knowledge of organic chemistry. The student will be trained in doing chemical computations and analysis.

TIME COMMITMENT (HRS/WK)

5

SKILLS/TECHNIQUES GAINED

High performance computing, chemical computations, analysis, physical and environmental chemistry, correlating experimental and computational modeling work

MENTORING PLAN

The student will meet with Prof. Vyas every week for 30 minutes. The student will also work with a graduate student who will train the MURF fellow, and will answer logistical questions. The research work will be utilized in national and international conferences as well as publications which will be co-authored by the MURF fellow.

PREFERRED STUDENT STATUS

Sophomore
Sophomore
Junior
Senior
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