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Migliorati V, D’Angelo P, Sessa F. Going beyond Radial Hydration Models: The Hidden Structures of Chloride and Iodide Aqua Ions Revealed by the Use of Lone Pairs. J Phys Chem B 2023; 127:10843-10850. [PMID: 38064661 PMCID: PMC10749448 DOI: 10.1021/acs.jpcb.3c06185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 12/22/2023]
Abstract
A novel model of hydration for the chloride and iodide ions in water is proposed, which overcomes the limitations of conventional radial models. A new approach, based on a representation of the halide lone pairs, highlighted a subset of first shell water molecules featuring preferential strong interactions with the ion lone pairs, giving rise to tetrahedral hydration structures in both Cl- and I- aqueous solutions. By adopting a novel descriptor correlated to the halide-water interaction energy, we were able to split the conventional first solvation shell into a tight first hydration shell, composed of water molecules strongly interacting with the ions via hydrogen bonds, and a loose first shell containing molecules that are only slightly perturbed by the halide electrostatic charge. The picture emerging from our findings indicates that lone pairs play an important role in the description of systems where hydrogen bonds are the main interactions taking place in the solvation process.
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Affiliation(s)
- Valentina Migliorati
- Dipartimento
di Chimica, “La Sapienza”
Università di Roma, P.le Aldo Moro 5, Rome 00185, Italy
| | - Paola D’Angelo
- Dipartimento
di Chimica, “La Sapienza”
Università di Roma, P.le Aldo Moro 5, Rome 00185, Italy
| | - Francesco Sessa
- Department
of Chemical Sciences, University of Naples
Federico II, Comp. Univ. Monte Sant’Angelo, Naples 80126, Italy
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2
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Smerigan A, Biswas S, Vila FD, Hong J, Perez-Aguilar J, Hoffman AS, Greenlee L, Getman RB, Bare SR. Aqueous Structure of Lanthanide-EDTA Coordination Complexes Determined by a Combined DFT/EXAFS Approach. Inorg Chem 2023; 62:14523-14532. [PMID: 37624729 DOI: 10.1021/acs.inorgchem.3c01334] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/27/2023]
Abstract
Sustainable production of rare earth elements (REEs) is critical for technologies needed for climate change mitigation, including wind turbines and electric vehicles. However, separation technologies currently used in REE production have large environmental footprints, necessitating more sustainable strategies. Aqueous, affinity-based separations are examples of such strategies. To make these technologies feasible, it is imperative to connect aqueous ligand structure to ligand selectivity for individual REEs. As a step toward this goal, we analyzed the extended X-ray absorption fine structure (EXAFS) of four lanthanides (La, Ce, Pr, and Nd) complexed by a common REE chelator, ethylenediaminetetraacetic acid (EDTA) to determine the aqueous-phase structure. Reference structures from density functional theory (DFT) were used to help fit the EXAFS spectra. We found that all four Ln-EDTA coordination complexes formed 9-coordinate structures with 6 coordinating atoms from EDTA (4 carboxyl oxygen atoms and 2 nitrogen atoms) and 3 oxygen atoms from water molecules. All EXAFS fits were of high quality (R-factor < 0.02) and showed decreasing average first-shell coordination distance across the series (2.62-2.57 Å from La-Nd), in agreement with DFT (2.65-2.56 Å from La-Nd). The insights determined herein will be useful in the development of ligands for sustainable rare earth elements (REE) separation technologies.
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Affiliation(s)
- Adam Smerigan
- Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Sayani Biswas
- Department of Chemical and Biomolecular Engineering, Clemson University, Clemson, South Carolina 29634, United States
| | - Fernando D Vila
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Jiyun Hong
- SSRL, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Jorge Perez-Aguilar
- SSRL, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Adam S Hoffman
- SSRL, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Lauren Greenlee
- Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Rachel B Getman
- Department of Chemical and Biomolecular Engineering, Clemson University, Clemson, South Carolina 29634, United States
| | - Simon R Bare
- SSRL, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
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3
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Rotermund BM, Sperling JM, Horne GP, Beck NB, Wineinger HB, Bai Z, Celis-Barros C, Gomez Martinez D, Albrecht-Schönzart TE. Co-Crystallization of Plutonium(III) and Plutonium(IV) Diglycolamides with Pu(III) and Pu(IV) Hexanitrato Anions: A Route to Redox Variants of [Pu III,IV(DGA) 3][Pu III,IV(NO 3) 6] x. Inorg Chem 2023; 62:12905-12912. [PMID: 37523261 DOI: 10.1021/acs.inorgchem.3c01590] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
N,N,N',N'-tetramethyl diglycolamide (TMDGA), a methylated variant of the diglycolamide extractants being proposed as curium holdback reagents in advanced used nuclear fuel reprocessing technologies, has been crystallized with plutonium, a transuranic actinide that has multiple accessible oxidation states. Two plutonium TMDGA complexes, [PuIII(TMDGA)3][PuIII(NO3)6] and[PuIV(TMDGA)3][PuIV(NO3)6]2·0.75MeOH, were crystallized through solvent diffusion of a reaction mixture containing plutonium(III) nitrate and TMDGA. The sample was then partially oxidized by air to yield [PuIV(TMDGA)3][PuIV(NO3)6]2·0.75MeOH. Single-crystal X-ray diffraction reveals that the multinuclear systems crystallize with hexanitrato anionic species, providing insight into the first solid-state isolation of the elusive trivalent plutonium hexanitrato species. Crystallography data show a change in geometry around the TMDGA metal center from Pu3+ to Pu4+, with the symmetry increasing approximately from C4v to D3h. These complexes provide a rare opportunity to investigate the bond metrics of plutonium in two different oxidation states with similar coordination environments. Further, these new structures provide insight into the potential chemical and structural differences arising from the radiation-induced formation of transient tetravalent curium oxidation states in used nuclear fuel reprocessing streams.
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Affiliation(s)
- Brian M Rotermund
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Joseph M Sperling
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
- Department of Chemistry and Nuclear Science and Engineering Center, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Gregory P Horne
- Center for Radiation Chemistry Research, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, Idaho 83415, United States
| | - Nicholas B Beck
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Hannah B Wineinger
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
- Department of Chemistry and Nuclear Science and Engineering Center, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Zhuanling Bai
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Cristian Celis-Barros
- Department of Chemistry and Nuclear Science and Engineering Center, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Daniela Gomez Martinez
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Thomas E Albrecht-Schönzart
- Department of Chemistry and Nuclear Science and Engineering Center, Colorado School of Mines, Golden, Colorado 80401, United States
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Yamamoto A, Liu X, Arashiba K, Konomi A, Tanaka H, Yoshizawa K, Nishibayashi Y, Yoshida H. Coordination Structure of Samarium Diiodide in a Tetrahydrofuran-Water Mixture. Inorg Chem 2023; 62:5348-5356. [PMID: 36728764 DOI: 10.1021/acs.inorgchem.2c03752] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Chemoselective reductive conversion of organic and inorganic compounds has been developed by the combination of samarium(II) diiodide (SmI2) and water. Despite the extensive previous studies to elucidate the role of water in the reactivity of SmI2, the direct structural data of the reactive Sm2+-water complexes, SmI2(H2O)n, in an organic solvent-water mixture have not been reported experimentally so far. Herein, we performed the structure analysis of the Sm2+-water complex in tetrahydrofuran (THF) in the presence of water by in situ X-ray absorption spectroscopy using high-energy X-rays (Sm K-edge, 46.8 keV). The analysis revealed the dissociation of the Sm2+-I bonds in the presence of ≥ eight equivalents of water in the THF-water mixture. The origin of the peak shift in the UV/visible absorption spectra after the addition of water into SmI2/THF solution was proposed based on electron transitions simulated with time-dependent density-functional-theory calculations using optimized structures in THF or water. The obtained structural information provides the fundamental insights for elucidating the reactivity and chemoselectivity in the Sm2+-water complex system.
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Affiliation(s)
- Akira Yamamoto
- Department of Interdisciplinary Environment, Graduate School of Human and Environmental Studies, Kyoto University, Yoshida Nihonmatsu-cho, Sakyo-ku, Kyoto606-8501, Japan.,Elements Strategy Initiative for Catalysts & Batteries (ESICB), Kyoto University, Kyotodaigaku Katsura, Nishikyo-ku, Kyoto615-8520, Japan
| | - Xueshi Liu
- Department of Interdisciplinary Environment, Graduate School of Human and Environmental Studies, Kyoto University, Yoshida Nihonmatsu-cho, Sakyo-ku, Kyoto606-8501, Japan
| | - Kazuya Arashiba
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo113-8656, Japan
| | - Asuka Konomi
- Institute for Materials Chemistry and Engineering, Kyushu University, Nishi-ku, Fukuoka819-0395, Japan
| | - Hiromasa Tanaka
- School of Liberal Arts and Sciences, Daido University, Minami-ku, Nagoya457-8530, Japan
| | - Kazunari Yoshizawa
- Elements Strategy Initiative for Catalysts & Batteries (ESICB), Kyoto University, Kyotodaigaku Katsura, Nishikyo-ku, Kyoto615-8520, Japan.,Institute for Materials Chemistry and Engineering, Kyushu University, Nishi-ku, Fukuoka819-0395, Japan
| | - Yoshiaki Nishibayashi
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo113-8656, Japan
| | - Hisao Yoshida
- Department of Interdisciplinary Environment, Graduate School of Human and Environmental Studies, Kyoto University, Yoshida Nihonmatsu-cho, Sakyo-ku, Kyoto606-8501, Japan.,Elements Strategy Initiative for Catalysts & Batteries (ESICB), Kyoto University, Kyotodaigaku Katsura, Nishikyo-ku, Kyoto615-8520, Japan
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D'Angelo P, Migliorati V, Gibiino A, Busato M. Direct Observation of Contact Ion-Pair Formation in La 3+ Methanol Solution. Inorg Chem 2022; 61:17313-17321. [PMID: 36255362 PMCID: PMC9627567 DOI: 10.1021/acs.inorgchem.2c02932] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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An approach combining molecular dynamics (MD) simulations
and X-ray
absorption spectroscopy (XAS) has been used to carry out a comparative
study about the solvation properties of dilute La(NO3)3 solutions in water and methanol, with the aim of elucidating
the still elusive coordination of the La3+ ion in the latter
medium. The comparison between these two systems enlightened a different
behavior of the nitrate counterions in the two environments: while
in water the La(NO3)3 salt is fully dissociated
and the La3+ ion is coordinated by water molecules only,
the nitrate anions are able to enter the metal first solvation shell
to form inner-sphere complexes in methanol solution. The speciation
of the formed complexes showed that the 10-fold coordination is preferential
in methanol solution, where the nitrate anions coordinate the La3+ cations in a monodentate fashion and the methanol molecules
complete the solvation shell to form an overall bicapped square antiprism
geometry. This is at variance with the aqueous solution where a more
balanced situation is observed between the 9- and 10-fold coordination.
An experimental confirmation of the MD results was obtained by La
K-edge XAS measurements carried out on 0.1 M La(NO3)3 solutions in the two solvents, showing the distinct presence
of the nitrate counterions in the La3+ ion first solvation
sphere of the methanol solution. The analysis of the extended X-ray
absorption fine structure (EXAFS) part of the absorption spectrum
collected on the methanol solution was carried out starting from the
MD results and confirmed the structural arrangement observed by the
simulations. The formation of contact ion pairs between
the La3+ ions and the nitrate anions has been demonstrated
in diluted methanol
solution using a combined approach using Molecular Dynamics simulations
and X-ray absorption spectroscpy.
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Affiliation(s)
- Paola D'Angelo
- Department of Chemistry, University of Rome "La Sapienza", P.le Aldo Moro 5, 00185 Rome, Italy
| | - Valentina Migliorati
- Department of Chemistry, University of Rome "La Sapienza", P.le Aldo Moro 5, 00185 Rome, Italy
| | - Alice Gibiino
- Department of Chemistry, University of Rome "La Sapienza", P.le Aldo Moro 5, 00185 Rome, Italy
| | - Matteo Busato
- Department of Chemistry, University of Rome "La Sapienza", P.le Aldo Moro 5, 00185 Rome, Italy
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Migliorati V, Busato M, D’Angelo P. Solvation structure of the Hg(NO3)2 and Hg(TfO)2 salts in dilute aqueous and methanol solutions: An insight into the Hg2+ coordination chemistry. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Busato M, Fazio G, Tavani F, Pollastri S, D'Angelo P. Solubilization and coordination of the HgCl 2 molecule in water, methanol, acetone, and acetonitrile: an X-ray absorption investigation. Phys Chem Chem Phys 2022; 24:18094-18102. [PMID: 35880669 DOI: 10.1039/d2cp02106d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
X-ray absorption spectroscopy (XAS) has been employed to carry out structural characterization of the local environment around mercury after the dissolution of the HgCl2 molecule. A combined EXAFS (extended X-ray absorption fine structure) and XANES (X-ray absorption near edge structure) data analysis has been performed on the Hg L3-edge absorption spectra recorded on 0.1 M HgCl2 solutions in water, methanol (MeOH), acetone and acetonitrile. The Hg-Cl distance determined by EXAFS (2.29(2)-2.31(2) Å) is always comparable to that found in the HgCl2 crystal (2.31(2) Å), demonstrating that the HgCl2 molecule dissolves in these solvents without dissociating. A small sensitivity of EXAFS to the solvent molecules interacting with HgCl2 has been detected and indicates a high degree of configurational disorder associated with this contribution. XANES data analysis, which is less affected by the disorder, was therefore carried out for the first time on these systems to shed light into the still elusive structural arrangement of the solvent molecules around HgCl2. The obtained results show that, in aqueous and MeOH solutions, the XANES data are compatible with three solvent molecules arranged around the HgCl2 unit to form a trigonal bipyramidal structure. The determination of the three-body Cl-Hg-Cl distribution shows a certain degree of uncertainty around the average 180° bond angle value, suggesting that the HgCl2 molecule probably vibrates in the solution around a linear configuration.
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Affiliation(s)
- Matteo Busato
- Department of Chemistry, University of Rome "La Sapienza", P.le A. Moro 5, 00185, Rome, Italy.
| | - Giuseppe Fazio
- Department of Chemistry, University of Rome "La Sapienza", P.le A. Moro 5, 00185, Rome, Italy.
| | - Francesco Tavani
- Department of Chemistry, University of Rome "La Sapienza", P.le A. Moro 5, 00185, Rome, Italy.
| | - Simone Pollastri
- Elettra-Sincrotrone Trieste S.C.p.A, s.s. 14, km 163.5, I-34149, Basovizza, Trieste, Italy
| | - Paola D'Angelo
- Department of Chemistry, University of Rome "La Sapienza", P.le A. Moro 5, 00185, Rome, Italy.
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Busato M, Tofoni A, Mannucci G, Tavani F, Del Giudice A, Colella A, Giustini M, D'Angelo P. On the Role of Water in the Formation of a Deep Eutectic Solvent Based on NiCl 2·6H 2O and Urea. Inorg Chem 2022; 61:8843-8853. [PMID: 35616906 PMCID: PMC9199011 DOI: 10.1021/acs.inorgchem.2c00864] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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The metal-based deep
eutectic solvent (MDES) formed by NiCl2·6H2O and urea in 1:3.5 molar ratio has been
prepared for the first time and characterized from a structural point
of view. Particular accent has been put on the role of water in the
MDES formation, since the eutectic could not be obtained with the
anhydrous form of the metal salt. To this end, mixtures at different
water/MDES molar ratios (W) have been studied with
a combined approach exploiting molecular dynamics and ab initio simulations, UV–vis and near-infra-red spectroscopies, small-
and wide-angle X-ray scattering, and X-ray absorption spectroscopy
measurements. In the pure MDES, a close packing of Ni2+ ion clusters forming oligomeric agglomerates is present thanks to
the mediation of bridging chloride anions and water molecules. Conversely,
urea poorly coordinates the metal ion and is mostly found in the interstitial
regions among the Ni2+ ion oligomers. This nanostructure
is disrupted upon the introduction of additional water, which enlarges
the Ni–Ni distances and dilutes the system up to an aqueous
solution of the MDES constituents. In the NiCl2·6H2O 1:3.5 MDES, the Ni2+ ion is coordinated on average
by one chloride anion and five water molecules, while water easily
saturates the metal solvation sphere to provide a hexa-aquo coordination
for increasing W values. This multidisciplinary study
allowed us to reconstruct the structural arrangement of the MDES and
its aqueous mixtures on both short- and intermediate-scale levels,
clarifying the fundamental role of water in the eutectic formation
and challenging the definition at the base of these complex systems. The metal-based deep eutectic solvent
formed by NiCl2·6H2O and urea in 1:3.5
a molar ratio was
prepared for the first time, and its aqueous mixtures were characterized
from a structural point of view, highlighting the fundamental role
of water in the eutectic formation.
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Affiliation(s)
- Matteo Busato
- Department of Chemistry, University of Rome "La Sapienza", P.le A. Moro 5, Rome 00185, Italy
| | - Alessandro Tofoni
- Department of Chemistry, University of Rome "La Sapienza", P.le A. Moro 5, Rome 00185, Italy
| | - Giorgia Mannucci
- Department of Chemistry, University of Rome "La Sapienza", P.le A. Moro 5, Rome 00185, Italy
| | - Francesco Tavani
- Department of Chemistry, University of Rome "La Sapienza", P.le A. Moro 5, Rome 00185, Italy
| | - Alessandra Del Giudice
- Department of Chemistry, University of Rome "La Sapienza", P.le A. Moro 5, Rome 00185, Italy
| | - Andrea Colella
- Department of Chemistry, University of Rome "La Sapienza", P.le A. Moro 5, Rome 00185, Italy
| | - Mauro Giustini
- Department of Chemistry, University of Rome "La Sapienza", P.le A. Moro 5, Rome 00185, Italy
| | - Paola D'Angelo
- Department of Chemistry, University of Rome "La Sapienza", P.le A. Moro 5, Rome 00185, Italy
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