19F NMR Characterization of the Encapsulation of Emerging Perfluoroethercarboxylic Acids by Cyclodextrins

• DOI: 10.1021/acs.jpcb.7b05901
• Publication Date: 2017-08-11T15:53:47Z
• Authors: Mary Jo Weiss-Errico; Ion Ghiviriga; Kevin E. O’Shea
• Keywords: Heteronuclear molecule; Proton NMR; Stoichiometry; Branching (polymer chemistry)

Legacy perfluoroalkyl substances (PFASs) are known environmental pollutants with serious adverse health effects. Perfluoroethercarboxylic acids (PFECAs), emerging PFASs now being substituted for legacy PFASs, have recently been detected in the environment. Cyclodextrins (CDs) proposed as agents remediation of problematic pollutants, including PFASs. The current study uses 19F NMR spectroscopy to measure complexation mono-, di-, and triether PFECAs by CDs eventual applications. Eight were characterized 13C NMR. change chemical shift individual fluorines upon at various stoichiometric ratios was used determine host–guest association constants. All studied most strongly encapsulated β-CD, constants from 102–105 M–1 depending on chain length number ether functionalities. 19F–1H heteronuclear Overhauser effect (HOESY) experiments performed β-CD complexes two branched monoethers, PFPrOPrA ("GenX") PFDMMOBA, elucidate structural details complexes, specific orientation, position along PFAS chain, assess roles hydrogen-bonding PFECA branching interactions. results give new understanding into fundamental nature complex between cyclodextrins perfluorinated surfactants.