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Citation
Tags
HERO ID
6311631
Reference Type
Journal Article
Title
A Self-Assembled Iron(II) Metallacage as a Trap for Per- and Polyfluoroalkyl Substances in Water
Author(s)
Fulong, CRP; Guardian, MGE; Aga, DS; Cook, TR
Year
2020
Is Peer Reviewed?
Yes
Journal
Inorganic Chemistry
ISSN:
0020-1669
EISSN:
1520-510X
Publisher
American Chemical Society
Volume
59
Issue
10
Page Numbers
6697-6708
Language
English
PMID
31909993
DOI
10.1021/acs.inorgchem.9b03405
Web of Science Id
WOS:000535304900006
Abstract
An anionic iron(II) tetrahedral molecular cage (FeMOP) was studied for its ability to interact with various per- and polyfluoroalkyl substances (PFASs) in aqueous media. Liquid chromatography tandem mass spectrometry revealed that longer-chain-length (more than six carbons) perfluorocarboxylic, -sulfonic, and fluorotelomers were removed from solution. In contrast, the steric bulk of N-ethyl substituted fluorosulfonamido acetic acid PFASs hindered association with the cage. Solution binding studies in D2O using 19F nuclear magnetic resonance (NMR) titrations and a Job plot show a 1:1 binding stoichiometry for perfluorohexanoic acid (PFHxA) and perfluoroheptanoic acid (PFHpA) with an association constant (Ka) of <103 and thus a favorable free energy of association (ΔG°). Perfluorononanoic acid (PFNA), on the other hand, forms an insoluble host-guest complex with FeMOP with a 1:1 host-guest ratio. Variable temperature (VT) NMR was used to determine the thermodynamic parameters of binding for a 1:1 FeMOP/PFHpA complex in water using a Curie-like model for fast-exchange processes. The extracted parameters suggest a low binding interaction (Ka < 103) driven by an increase in entropy from cage desolvation upon guest binding. The solid-state host-guest complexes formed from solution complexation of PFHxA, PFHpA, and PFNA into the cage were characterized by infrared spectroscopy (FT-IR) and powder X-ray diffraction (PXRD) methods. FT-IR studies suggest an interaction between the fluorocarbon groups of PFASs to the phenylsulfonate functional groups of the ligand. A docking model predicted by computation also indicates this interaction may occur, with the PFASs adsorbing onto the surface of the cage rather than forming a true host-guest complex within the internal cavity. PXRD studies reveal a crystal packing of the complex that is very similar to that of the water-treated FeMOP, with the exception of 1:2 FeMOP/PFNA and 1:1 and 2:1 FeMOP/PFHpA.
Tags
PFAS
•
Additional PFAS (formerly XAgency)
•
Expanded PFAS SEM (formerly PFAS 430)
Perfluorooctane
•
PFAS 150
Literature Search Update December 2021
PubMed
Missing 2021 searches
Literature Search Update December 2020
PubMed
Literature Search August 2019
PubMed
Not prioritized for screening
Perfluorohexanoic acid
•
PFHxA
LitSearch Update: May 2019 - May 2020
PubMed
Scopus: April 2021
HAWC
•
PFNA
Literature Search
Pubmed
WOS
LitSearch: May 2019 - May 2020
PubMed
LitSearch: May 2020 - April 2021
PubMed
WoS
Title and Abstract Screening
Excluded
Not relevant to PECO
•
PFOA (335-67-1) and PFOS (1763-23-1)
Literature Search Update (Apr 2019 - Sep 2020)
WOS
LitSearch Update (Sept 2020 - Feb 2022)
WOS
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