1
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Benthin GC, Rajapaksha H, Markun EL, Mason SE, Forbes TZ. Probing the protonation and reduction of heptavalent neptunium with computational guidance. Dalton Trans 2024; 53:16170-16185. [PMID: 39297786 DOI: 10.1039/d4dt01706d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/09/2024]
Abstract
Influence of pH on the speciation and stability of heptavalent neptunium is poorly understood although it is frequently invoked in the literature to explain experimental observations. The present study employs Density Functional Theory (DFT) methodology to assess the thermodynamic feasibility of protonation reactions for the Np(VII) anion complex and the impact on its reduction to Np(VI). This theoretical framework is then explored experimentally through the titration and systematic protonation of Np(VII) in solution and solid-state samples while monitoring them spectroscopically. Computational results reveal that protonation reactions with the axial OH- ligands of the Np(VII) anionic complex, [NpO4(OH)2]3-, are more thermodynamically favorable than the equatorial oxo ligands. In addition, DFT studies indicated that up to four sequential protonation reactions may be feasible before reduction becomes thermodynamically favorable. Experimental results also uncover that protonation leads to distinct changes in the observable vibrational signals and UV-Vis absorption features. Overall, we observed that the protonation of [NpO4(OH)2]3- in solution and in the solid-state occurs before reduction to the Np(VI)O22+ species.
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Affiliation(s)
- Grant C Benthin
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA.
| | | | - Emma L Markun
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA.
| | - Sara E Mason
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA.
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973, USA.
| | - Tori Z Forbes
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA.
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2
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Peng X, Zhang M, Qin H, Han J, Xu Y, Li W, Zhang XP, Zhang W, Apfel UP, Cao R. Switching Electrocatalytic Hydrogen Evolution Pathways through Electronic Tuning of Copper Porphyrins. Angew Chem Int Ed Engl 2024; 63:e202401074. [PMID: 38311965 DOI: 10.1002/anie.202401074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 02/02/2024] [Accepted: 02/03/2024] [Indexed: 02/06/2024]
Abstract
The electronic structure of metal complexes plays key roles in determining their catalytic features. However, controlling electronic structures to regulate reaction mechanisms is of fundamental interest but has been rarely presented. Herein, we report electronic tuning of Cu porphyrins to switch pathways of the hydrogen evolution reaction (HER). Through controllable and regioselective β-oxidation of Cu porphyrin 1, we synthesized analogues 2-4 with one or two β-lactone groups in either a cis or trans configuration. Complexes 1-4 have the same Cu-N4 core site but different electronic structures. Although β-oxidation led to large anodic shifts of reductions, 1-4 displayed similar HER activities in terms of close overpotentials. With electrochemical, chemical and theoretical results, we show that the catalytically active species switches from a CuI species for 1 to a Cu0 species for 4. This work is thus significant to present mechanism-controllable HER via electronic tuning of catalysts.
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Affiliation(s)
- Xinyang Peng
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
| | - Mengchun Zhang
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
| | - Haonan Qin
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
| | - Jinxiu Han
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
| | - Yuhan Xu
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
| | - Wenzi Li
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
| | - Xue-Peng Zhang
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
| | - Wei Zhang
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
| | - Ulf-Peter Apfel
- Ruhr-Universität Bochum, Fakultät für Chemie und Biochemie, Anorganische Chemie I, Universitätsstrasse 150, 44801, Bochum, Germany
- Fraunhofer UMSICHT, Osterfelder Strasse 3, 46047, Oberhausen, Germany
| | - Rui Cao
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
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3
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Rajapaksha H, Benthin GC, Markun EL, Mason SE, Forbes TZ. Synthesis, characterization, and density functional theory investigation of (CH 6N 3) 2[NpO 2Cl 3] and Rb[NpO 2Cl 2(H 2O)] chain structures. Dalton Trans 2024. [PMID: 38265201 DOI: 10.1039/d3dt03630h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
The actinyl tetrachloro complex [An(V/VI)O2Cl4]2-/3- tends to form discrete molecular units in both solution and solid state materials, but related aquachloro complexes have been observed as both discrete coordination compounds and 1-D chain topologies. Subtle differences in the inner sphere coordination significantly influence the formation of structural topologies in the actinyl chloride system, but the exact reasoning for these variations has not been delineated. In the current study, we present the synthesis, structural characterization, and vibrational analysis of two 1-D neptunyl(V) chain compounds: (CH6N3)2[NpO2Cl3] (Np-Gua) and Rb[NpO2Cl2(H2O)] (Np-Rb). Bonding and non-covalent interactions (NCIs) in the systems were evaluated using periodic Density Functional Theory (DFT) to link these properties to related phases. We observed ∼6.5% and ∼3.9% weakening of NpO bonds in Np-Gua and Np-Rb compared to the reference Cs3[NpO2Cl4]. NCI analysis distinguished specific assembly modes, where Np-Gua was connected via hydrogen bonding (N-H⋯Cleq and N-H⋯Oyl) and Np-Rb contained both cation interactions (Rb+⋯Oyl and Rb+⋯Cleq) and hydrogen bonding (Oeq-H⋯Oyl) networks. Thermodynamically viable formation pathways for both compounds were explored using DFT methodology. The [NpO2Cl4](aq)3- and [NpO2Cl3(H2O)](aq)2- substructures were identified as precursors to Np-Gua and [NpO2Cl3(H2O)](aq)2- and [NpO2Cl2(H2O)2](aq)- were isolated as the primary building units of Np-Rb. Finally, we utilized DFT to analyze the vibrational modes for Np-Gua and Np-Rb, where we found evidence of the NpO bond weakening within the Np(V) chain structures compared to [NpO2Cl4]3-.
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Affiliation(s)
| | - Grant C Benthin
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA.
| | - Emma L Markun
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA.
| | - Sara E Mason
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA.
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973, USA.
| | - Tori Z Forbes
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA.
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4
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Yang Y, Wei S, Zhao Z, Chen J, Wang J, Hu H, Minasian SG, Sun T. Synthesis, Structure, and Theoretical Calculations on NpO 2Br 42. Inorg Chem 2023; 62:13953-13963. [PMID: 37584949 DOI: 10.1021/acs.inorgchem.3c01891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/17/2023]
Abstract
The actinide-halogen complexes (AnO2X42-, X = Cl, Br, and I) are the simplest and most representative compounds for studying the bonding nature of actinides with ligands. In this work, we attempted to synthesize the crystals of NpO2X42- (X = Cl, Br, and I). The crystals of NpO2Cl42- and NpO2Br42- were successfully synthesized, in which the structure of NpO2Br42- was obtained for the first time. The crystal of NpO2I42- could not be obtained due to the rapid reduction of Np(VI) to Np(V) by I-. The molecular structures of NpO2Cl42- and NpO2Br42- were characterized by single-crystal X-ray diffraction and infrared, Raman, and UV-Vis-NIR absorption spectroscopy. The complexes of NpO2X42- (X = Cl, Br, and I) were also investigated by density functional theory calculations, and the calculated vibration frequencies and absorption features were comparable to the experimental results. Both the experimental results and theoretical calculations demonstrate the strengthened Np-O bonds and the weakened Np-X bonds across the NpO2X42- series; however, the population analysis on the frontier molecular orbitals (MOs) of NpO2X42- indicates a slight reduction in the Np-O bonding covalency and an enhancement in the Np-X bonding covalency from NpO2Cl42- to NpO2I42-. Results in this work have enriched the crystal database of the AnO2X42- family and provided insights into the bonding nature in the actinide complexes with soft- and hard-donor ligands.
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Affiliation(s)
- Yuning Yang
- Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
| | - Shiru Wei
- Department of Chemistry & Key Laboratory of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Tsinghua University, Beijing 100084, China
| | - Zhijin Zhao
- Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
| | - Jing Chen
- Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
| | - Jianchen Wang
- Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
| | - Hanshi Hu
- Department of Chemistry & Key Laboratory of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Tsinghua University, Beijing 100084, China
| | - Stefan G Minasian
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Taoxiang Sun
- Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
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5
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Augustine LJ, Rajapaksha H, Pyrch MMF, Kasperski M, Forbes TZ, Mason SE. Periodic Density Functional Theory Calculations of Uranyl Tetrachloride Compounds Engaged in Uranyl-Cation and Uranyl-Hydrogen Interactions: Electronic Structure, Vibrational, and Thermodynamic Analyses. Inorg Chem 2023; 62:372-380. [PMID: 36538814 PMCID: PMC9832540 DOI: 10.1021/acs.inorgchem.2c03476] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Solid-state uranyl hybrid structures are often formed through unique intermolecular interactions occurring between a molecular uranyl anion and a charge-balancing cation. In this work, solid-state structures of the uranyl tetrachloride anion engaged in uranyl-cation and uranyl-hydrogen interactions were studied using density functional theory (DFT). As most first-principles methods used for systems of this type focus primarily on the molecular structure, we present an extensive benchmarking study to understand the methods needed to accurately model the geometric properties of these systems. From there, the electronic and vibrational structures of the compounds were investigated through projected density of states and phonon analysis and compared to the experiment. Lastly, we present a DFT + thermodynamics approach to calculate the formation enthalpies (ΔHf) of these systems to directly relate to experimental values. Through this methodology, we were able to accurately capture trends observed in experimental results and saw good quantitative agreement in predicted ΔHf compared to the value calculated through referencing each structure to its standard state. Overall, results from this work will be used for future combined experimental and computational studies on both uranyl and neptunyl hybrid structures to delineate how varying intermolecular interaction strengths relates to the overall values of ΔHf.
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Affiliation(s)
- Logan J Augustine
- Department of Chemistry, University of Iowa, Iowa City, Iowa52242, United States
| | - Harindu Rajapaksha
- Department of Chemistry, University of Iowa, Iowa City, Iowa52242, United States
| | - Mikaela Mary F Pyrch
- Department of Chemistry, University of Iowa, Iowa City, Iowa52242, United States
| | - Maguire Kasperski
- Department of Chemistry, University of Iowa, Iowa City, Iowa52242, United States
| | - Tori Z Forbes
- Department of Chemistry, University of Iowa, Iowa City, Iowa52242, United States
| | - Sara E Mason
- Department of Chemistry, University of Iowa, Iowa City, Iowa52242, United States
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6
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Yoo S, Qiao B, Douglas T, Bu W, Olvera de la Cruz M, Dutta P. Specific Ion Effects in Lanthanide-Amphiphile Structures at the Air-Water Interface and Their Implications for Selective Separation. ACS APPLIED MATERIALS & INTERFACES 2022; 14:7504-7512. [PMID: 35099919 DOI: 10.1021/acsami.1c24008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The use of surfactants to attract dissolved ions to water surfaces and interfaces is an essential step in both solvent-based and solvent-free separation processes. We have studied the interactions of lanthanide ions in the aqueous subphase with monolayers of dihexadecyl phosphate at air-water interfaces. With heavier lanthanides (atomic number Z ≥ 65) in the subphase, the floating layer can be compressed to an area/molecule of about half the molecular cross section, indicating bilayer formation. X-ray fluorescence and reflectivity data support this conclusion. In the presence of lighter lanthanides (Z < 65), only monolayers are observed. Subphase-concentration-dependent studies using Er3+ (heavier) and Nd3+ (lighter) lanthanides show a stepwise progression, with ions attaching to the monolayer only when the solution concentration is >3 × 10-7 M. Above ∼10-5 M, bilayers form but only in the presence of the heavier lanthanide. Grazing incidence X-ray diffraction shows evidence of lateral ion-ion correlations in the bilayer structure but not in monolayers. Explicit solvent all-atom molecular dynamics simulations confirm the elevated ion-ion correlation in the bilayer system. This bilayer structure isolates heavier lanthanides but not lighter lanthanides from an aqueous solution and is therefore a potential mechanism for the selective separation of heavier lanthanides.
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Affiliation(s)
- Sangjun Yoo
- Department of Physics & Astronomy, Northwestern University, Evanston, Illinois 60208, United States
| | - Baofu Qiao
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Travis Douglas
- Department of Physics & Astronomy, Northwestern University, Evanston, Illinois 60208, United States
| | - Wei Bu
- Center for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60637, United States
| | - Monica Olvera de la Cruz
- Department of Physics & Astronomy, Northwestern University, Evanston, Illinois 60208, United States
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Pulak Dutta
- Department of Physics & Astronomy, Northwestern University, Evanston, Illinois 60208, United States
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7
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Li Z, Dewulf B, Binnemans K. Nonaqueous Solvent Extraction for Enhanced Metal Separations: Concept, Systems, and Mechanisms. Ind Eng Chem Res 2021; 60:17285-17302. [PMID: 34898845 PMCID: PMC8662634 DOI: 10.1021/acs.iecr.1c02287] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 10/06/2021] [Accepted: 10/27/2021] [Indexed: 11/30/2022]
Abstract
Efficient and sustainable separation of metals is gaining increasing attention, because of the essential roles of many metals in sustainable technologies for a climate-neutral society, such as rare earths in permanent magnets and cobalt, nickel, and manganese in the cathode materials of lithium-ion batteries. The separation and purification of metals by conventional solvent extraction (SX) systems, which consist of an organic phase and an aqueous phase, has limitations. By replacing the aqueous phase with other polar solvents, either polar molecular organic solvents or ionic solvents, nonaqueous solvent extraction (NASX) largely expands the scope of SX, since differences in solvation of metal ions lead to different distribution behaviors. This Review emphasizes enhanced metal extraction and remarkable metal separations observed in NASX systems and discusses the effects of polar solvents on the extraction mechanisms according to the type of polar solvents and the type of extractants. Furthermore, the considerable effects of the addition of water and complexing agents on metal separations in terms of metal ion solvation and speciation are highlighted. Efforts to integrate NASX into metallurgical flowsheets and to develop closed-loop solvometallurgical processes are also discussed. This Review aims to construct a framework of NASX on which many more studies on this topic, both fundamental and applied, can be built.
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Affiliation(s)
| | | | - Koen Binnemans
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Heverlee, Belgium
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8
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MacInnes MM, Jones ZR, Li B, Anderson NH, Batista ER, DiMucci IM, Eiroa-Lledo C, Knope KE, Livshits MY, Kozimor SA, Mocko V, Pace KA, Rocha FR, Stein BW, Wacker JN, Yang P. Using molten salts to probe outer-coordination sphere effects on lanthanide(III)/(II) electron-transfer reactions. Dalton Trans 2021; 50:15696-15710. [PMID: 34693951 DOI: 10.1039/d1dt02708e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Controlling structure and reactivity by manipulating the outer-coordination sphere around a given reagent represents a longstanding challenge in chemistry. Despite advances toward solving this problem, it remains difficult to experimentally interrogate and characterize outer-coordination sphere impact. This work describes an alternative approach that quantifies outer-coordination sphere effects. It shows how molten salt metal chlorides (MCln; M = K, Na, n = 1; M = Ca, n = 2) provided excellent platforms for experimentally characterizing the influence of the outer-coordination sphere cations (Mn+) on redox reactions accessible to lanthanide ions; Ln3+ + e1- → Ln2+ (Ln = Eu, Yb, Sm; e1- = electron). As a representative example, X-ray absorption spectroscopy and cyclic voltammetry results showed that Eu2+ instantaneously formed when Eu3+ dissolved in molten chloride salts that had strongly polarizing cations (like Ca2+ from CaCl2) via the Eu3+ + Cl1- → Eu2+ + ½Cl2 reaction. Conversely, molten salts with less polarizing outer-sphere M1+ cations (e.g., K1+ in KCl) stabilized Ln3+. For instance, the Eu3+/Eu2+ reduction potential was >0.5 V more positive in CaCl2 than in KCl. In accordance with first-principle molecular dynamics (FPMD) simulations, we postulated that hard Mn+ cations (high polarization power) inductively removed electron density from Lnn+ across Ln-Cl⋯Mn+ networks and stabilized electron-rich and low oxidation state Ln2+ ions. Conversely, less polarizing Mn+ cations (like K1+) left electron density on Lnn+ and stabilized electron-deficient and high-oxidation state Ln3+ ions.
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Affiliation(s)
- Molly M MacInnes
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Zachary R Jones
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Bo Li
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Nickolas H Anderson
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Enrique R Batista
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Ida M DiMucci
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Cecilia Eiroa-Lledo
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Karah E Knope
- Department of Chemistry, Georgetown University, 37th and O Streets NW, Washington, D.C. 20057, USA
| | - Maksim Y Livshits
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Stosh A Kozimor
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Veronika Mocko
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Kristen A Pace
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Francisca R Rocha
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Benjamin W Stein
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Jennifer N Wacker
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA. .,Department of Chemistry, Georgetown University, 37th and O Streets NW, Washington, D.C. 20057, USA
| | - Ping Yang
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
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9
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Gilson SE, Burns PC. The crystal and coordination chemistry of neptunium in all its oxidation states: An expanded structural hierarchy of neptunium compounds. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.213994] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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10
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Wacker JN, Nicholas AD, Vasiliu M, Marwitz AC, Bertke JA, Dixon DA, Knope KE. Impact of Noncovalent Interactions on the Structural Chemistry of Thorium(IV)-Aquo-Chloro Complexes. Inorg Chem 2021; 60:6375-6390. [PMID: 33885290 DOI: 10.1021/acs.inorgchem.1c00099] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Five novel tetravalent thorium (Th) compounds that consist of Th(H2O)xCly structural units were isolated from acidic aqueous solutions using a series of nitrogen-containing heterocyclic hydrogen (H) bond donors. Taken together with three previously reported phases, the compounds provide a series of monomeric ThIV complexes wherein the effects of noncovalent interactions (and H-bond donor identity) on Th structural chemistry can be examined. Seven distinct structural units of the general formulas [Th(H2O)xCl8-x]x-4 (x = 2, 4) and [Th(H2O)xCl9-x]x-5 (x = 5-7) are described. The complexes range from chloride-deficient [Th(H2O)7Cl2]2+ to chloride-rich [Th(H2O)2Cl6]2- species, and theory was used to understand the relative energies that separate complexes within this series via the stepwise chloride addition to an aquated Th cation. Electronic structure theory predicted the reaction energies of chloride addition and release of water through a series of transformations, generally highlighting an energetic driving force for chloride complexation. To probe the role of the counterion in the stabilization of these complexes, electrostatic potential (ESP) surfaces were calculated. The ESP surfaces indicated a dependence of the chloride distribution about the Th metal center on the pKa of the countercation, highlighting the directing effects of noncovalent interactions (e.g., Hbonding) on Th speciation.
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Affiliation(s)
- Jennifer N Wacker
- Department of Chemistry, Georgetown University, Washington, D.C. 20057, United States
| | - Aaron D Nicholas
- Department of Chemistry, The George Washington University, Washington, D.C. 20052, United States
| | - Monica Vasiliu
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Alexander C Marwitz
- Department of Chemistry, Georgetown University, Washington, D.C. 20057, United States
| | - Jeffery A Bertke
- Department of Chemistry, Georgetown University, Washington, D.C. 20057, United States
| | - David A Dixon
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Karah E Knope
- Department of Chemistry, Georgetown University, Washington, D.C. 20057, United States
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11
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Pyrch MM, Bjorklund JL, Williams JM, Parr Iv DL, Mason SE, Leddy J, Forbes TZ. Impacts of hydrogen bonding interactions with Np(v/vi)O 2Cl 4 complexes: vibrational spectroscopy, redox behavior, and computational analysis. Dalton Trans 2020; 49:6854-6866. [PMID: 32383725 DOI: 10.1039/d0dt00848f] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The neptunyl (Np(v)O2+/Np(vi)O22+) cation is the dominant form of 237Np in acidic aqueous solutions and the stability of the Np(v) and Np(vi) species is driven by the specific chemical constituents present in the system. Hydrogen bonding with the oxo group may impact the stability of these species, but there is limited understanding of how these intermolecular interactions influence the behavior of both solution and solid-state species. In the current study, we systematically evaluate the interactions between the neptunyl tetrachloride species and hydrogen donors in coordination complexes and in the related aqueous solutions. Both Np(v) compounds (N2C4H12)2[Np(v)O2Cl4]Cl (Np(V)pipz) and (NOC4H10)3[Np(v)O2Cl4] (Np(V)morph) exhibit directional hydrogen bonding to the neptunyl oxo group while Np(vi) compounds (NC5H6)2[Np(vi)O2Cl4] (Np(VI)pyr) and (NOC4H10)4[Np(vi)O2Cl4]·2Cl (Np(VI)morph) assemble via halogen interactions. The Raman spectra of the solid-state phases indicate the activation of vibrational bands when there is asymmetry of the neptunyl bond, while these spectral features are not observed within the related solution phase spectra. Density functional theory calculations of the Np(V)pipz system suggest that activation of the ν3 asymmetric stretch and other combination modes lead to additional complexity within the solid-state spectra. Electrochemical analyses of complexes in the solution phases are consistent with the results of the crystallization experiments as the voltammetric potentials of Np(v)/Np(vi) complexes in the presence of protonated heterocycles differ from the potentials of pure Np(v) and may correlate with the hydrogen bonding interactions.
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Affiliation(s)
- Mikaela M Pyrch
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA.
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12
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Yue Z, Guo X, Feng ML, Lin YJ, Ju Y, Lin X, Zhang ZH, Guo X, Lin J, Huang YY, Wang JQ. Unexpected Roles of Alkali-Metal Cations in the Assembly of Low-Valent Uranium Sulfate Molecular Complexes. Inorg Chem 2020; 59:2348-2357. [PMID: 32017542 DOI: 10.1021/acs.inorgchem.9b03182] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The directing effect of coordinating ligands in the formation of uranium molecular complexes has been well established, but the role of counterions in metal-ligand interactions remains ambiguous and requires further investigation. In this work, we describe the targeted isolation, through the choice of alkali-metal ions, of a family of tetravalent uranium sulfates, showing the influence of the overall topology and, unexpectedly, the UIV nuclearity upon the inclusion of such countercations. Analyses of the structures of uranium(IV) oxo/hydroxosulfate oligomeric species isolated from consistent synthetic conditions reveal that the incorporation of Na+ and Rb+ promotes the crystallization of 0D discrete clusters with a hexanuclear [U6O4(OH)4(H2O)4]12+ core, whereas the larger Cs+ ion allows for the isolation of a 2D-layered oligomer with a less condensed trinuclear [U3(O)]10+ center. This finding expands the prevalent view that counterions play an innocent role in molecular complex synthesis, affecting only the overall packing but not the local oligomerization. Interestingly, trends in nuclearity appear to correlate with the hydration enthalpies of alkali-metal cations, such that the alkali-metal cations with larger hydration enthalpies correspond to more hydrated complexes and cluster cores. These findings afford new insights into the mechanism of nucleation of UIV, and they also open a new path for the rational design and synthesis of targeted molecular complexes.
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Affiliation(s)
- Zenghui Yue
- Key Laboratory of Interfacial Physics and Technology , Shanghai Institute of Applied Physics, Chinese Academy of Sciences , 2019 Jia Luo Road , Shanghai 201800 , China.,University of Chinese Academy of Sciences , No. 19(A) Yuquan Road , Shijingshan District, Beijing 100049 , China.,Shanghai Advanced Research Institute, Chinese Academy of Sciences , Shanghai 201210 , China
| | - Xiaofeng Guo
- Department of Chemistry , Washington State University , Pullman , Washington 99164-4630 , United States
| | - Mei-Ling Feng
- State Key Laboratory of Structural Chemistry , Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou , Fujian 350002 , China
| | - Yue-Jian Lin
- Department of Chemistry , Fudan University , 220 Handan Road , Shanghai 200433 , China
| | - Yu Ju
- Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology , Changzhou University , Changzhou 213164 , China
| | - Xiao Lin
- Key Laboratory of Interfacial Physics and Technology , Shanghai Institute of Applied Physics, Chinese Academy of Sciences , 2019 Jia Luo Road , Shanghai 201800 , China
| | - Zhi-Hui Zhang
- Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology , Changzhou University , Changzhou 213164 , China
| | - Xiaojing Guo
- The Education Ministry Key Laboratory of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials, Department of Chemistry and Chemical Engineering , Shanghai Normal University , 100 Guilin Road , Shanghai 200234 , China
| | - Jian Lin
- Key Laboratory of Interfacial Physics and Technology , Shanghai Institute of Applied Physics, Chinese Academy of Sciences , 2019 Jia Luo Road , Shanghai 201800 , China
| | - Yu-Ying Huang
- Shanghai Advanced Research Institute, Chinese Academy of Sciences , Shanghai 201210 , China
| | - Jian-Qiang Wang
- Key Laboratory of Interfacial Physics and Technology , Shanghai Institute of Applied Physics, Chinese Academy of Sciences , 2019 Jia Luo Road , Shanghai 201800 , China
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13
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Li Z, Onghena B, Li X, Zhang Z, Binnemans K. Enhancing Metal Separations Using Hydrophilic Ionic Liquids and Analogues as Complexing Agents in the More Polar Phase of Liquid-Liquid Extraction Systems. Ind Eng Chem Res 2019; 58:15628-15636. [PMID: 31598033 PMCID: PMC6776877 DOI: 10.1021/acs.iecr.9b03472] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 08/02/2019] [Accepted: 08/05/2019] [Indexed: 11/29/2022]
Abstract
The separation of metals by liquid-liquid extraction largely relies on the affinity of metals to the extractants, which normally reside in the organic (less polar) phase because of their high hydrophobicity. Following a different route, using aminopoly(carboxylic acid)s (e.g., EDTA) as complexing agents in the aqueous (more polar) phase was found to enhance metal separations by selectively complexing metal cations. In this study, we demonstrate that, hydrophilic ionic liquids and analogues in the more polar phase could also selectively complex with metal cations and hence enhance metal separations. As an example, Cyanex 923 (a mixture of trialkyl phosphine oxides) dissolved in p-cymene extracts CoCl2 more efficiently than SmCl3 from a chloride ethylene glycol (EG) solution. However, when tetraethylammonium chloride is added into the EG solution, CoCl2 is selectively held back (only 1.2% extraction at 3.0 M tetraethylammonium chloride), whereas the extraction of SmCl3 is unaffected (89.9% extraction), leading to reversed metal separation with a separation factor of Sm(III)/Co(II) > 700. The same principle is applicable to a range of hydrophilic ionic liquids, which can be used as complexing agents in the more polar phase to enhance the separations of various metal mixtures by liquid-liquid extraction.
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Affiliation(s)
- Zheng Li
- Department of Chemistry, KU Leuven, Heverlee B-3001, Belgium
| | - Bieke Onghena
- Department of Chemistry, KU Leuven, Heverlee B-3001, Belgium
| | - Xiaohua Li
- Department of Chemistry, KU Leuven, Heverlee B-3001, Belgium
| | - Zidan Zhang
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
| | - Koen Binnemans
- Department of Chemistry, KU Leuven, Heverlee B-3001, Belgium
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14
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Wacker JN, Vasiliu M, Colliard I, Ayscue RL, Han SY, Bertke JA, Nyman M, Dixon DA, Knope KE. Monomeric and Trimeric Thorium Chlorides Isolated from Acidic Aqueous Solution. Inorg Chem 2019; 58:10871-10882. [DOI: 10.1021/acs.inorgchem.9b01238] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Jennifer N. Wacker
- Department of Chemistry, Georgetown University, 37th and O Streets NW, Washington, D.C. 20057, United States
| | - Monica Vasiliu
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Ian Colliard
- Oregon State University, Department of Chemistry, Corvallis, Oregon 97331, United States
| | - R. Lee Ayscue
- Department of Chemistry, Georgetown University, 37th and O Streets NW, Washington, D.C. 20057, United States
| | - Sae Young Han
- Department of Chemistry, Georgetown University, 37th and O Streets NW, Washington, D.C. 20057, United States
| | - Jeffery A. Bertke
- Department of Chemistry, Georgetown University, 37th and O Streets NW, Washington, D.C. 20057, United States
| | - May Nyman
- Oregon State University, Department of Chemistry, Corvallis, Oregon 97331, United States
| | - David A. Dixon
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Karah E. Knope
- Department of Chemistry, Georgetown University, 37th and O Streets NW, Washington, D.C. 20057, United States
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15
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Wacker JN, Han SY, Murray AV, Vanagas NA, Bertke JA, Sperling JM, Surbella RG, Knope KE. From Thorium to Plutonium: Trends in Actinide(IV) Chloride Structural Chemistry. Inorg Chem 2019; 58:10578-10591. [DOI: 10.1021/acs.inorgchem.9b01279] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Jennifer N. Wacker
- Department of Chemistry, Georgetown University, 37th and O Streets NW, Washington, D.C. 20057, United States
| | - Sae Young Han
- Department of Chemistry, Georgetown University, 37th and O Streets NW, Washington, D.C. 20057, United States
| | - Aphra V. Murray
- Department of Chemistry, Georgetown University, 37th and O Streets NW, Washington, D.C. 20057, United States
| | - Nicole A. Vanagas
- Department of Chemistry, Georgetown University, 37th and O Streets NW, Washington, D.C. 20057, United States
| | - Jeffery A. Bertke
- Department of Chemistry, Georgetown University, 37th and O Streets NW, Washington, D.C. 20057, United States
| | - Joseph M. Sperling
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Robert G. Surbella
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354, United States
| | - Karah E. Knope
- Department of Chemistry, Georgetown University, 37th and O Streets NW, Washington, D.C. 20057, United States
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