Unsaturated Sulfur Crown Ethers Can Extract Mercury(II) and Show Promise for Future Copernicium(II) Studies: A Combined Experimental and Computational Study

Ferrier, Maryline G. and Valdez, Carlos A. and Singh, Saurabh Kumar and et al, . (2022) Unsaturated Sulfur Crown Ethers Can Extract Mercury(II) and Show Promise for Future Copernicium(II) Studies: A Combined Experimental and Computational Study. Inorganic Chemistry, 61 (2). pp. 807-817. ISSN 0020-1669

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Abstract

The unsaturated hexathia-18-crown-6 (UHT18C6) molecule was investigated for the extraction of Hg(II) in HCl and HNO3 media. This extractant can be directly compared to the recently studied saturated hexathia-18-crown-6 (HT18C6). The default conformation of the S lone pairs in UHT18C6 is endodentate, where the pocket of the charge density, according to the crystal structures, is oriented toward the center of the ring, which should allow better extraction for Hg(II) compared to the exodentate HT18C6. Batch study experiments showed that Hg(II) had better extraction at low acid molarity (ca. 99% in HCl and ca. 95% in HNO3), while almost no extraction was observed above 0.4 M HCl and 4 M HNO3 (<5%). Speciation studies were conducted with the goal of delineating a plausible extraction mechanism. Density functional theory calculations including relativistic effects were carried out on both Hg(II)-encapsulated HT18C6 and UHT18C6 complexes to shed light on the binding strength and the nature of bonding. Our calculations offer insights into the extraction mechanism. In addition to Hg(II), calculations were performed on the hypothetical divalent Cn(II) ion, and showed that HT18C6 and UHT18C6 could extract Cn(II). Finally, the extraction kinetics were explored to assess whether this crown can extract the short-lived Cn(II) species in a future online experiment. © 2021 American Chemical Society.

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IITH Creators:

IITH Creators	ORCiD
Singh, Saurabh Kumar	UNSPECIFIED

Item Type:

Article

Additional Information:

This study was performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344. This work was funded by the Laboratory and Development Program at LLNL under Project 19-ERD-003. This material is based upon work supported by the Department of Energy National Nuclear Security Administration through the Nuclear Science and Security Consortium under Award DE-NA0003180. The computational part of this work was funded by the Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences, U.S. Department of Energy, through Grant DE-SC002183 (to L.G. and D.R.). S.K.S. acknowledges the Department of Science and Technology for the Start-up Research Grant SRG/2020/001323 and IIT Hyderabad for generous funding. The authors thank the CAMS facility staff at LLNL, specifically Scott Tumey, Thomas Brown, and Grahm Bench for providing beam time and expertise to the production of radionuclides used in this study. Calculations were performed at the Minnesota Supercomputing Institute.

Uncontrolled Keywords:

18-crown-6; Batch studies; Computational studies; Crown-ethers; Crystals structures; Extractants; Extraction mechanisms; Lone pair; Lower acids; Molarity

Subjects:

Others > Chemical sciences
Chemistry

Divisions:

Department of Chemistry

Depositing User:

. LibTrainee 2021

Date Deposited:

14 Jul 2022 12:47

Last Modified:

14 Jul 2022 12:47

URI:

http://raiithold.iith.ac.in/id/eprint/9706