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Dutra FR, Vasiliu M, Gomez AN, Xia D, Dixon DA. Prediction of Redox Potentials for U, Np, Pu, and Am in Aqueous Solution. J Phys Chem A 2024; 128:5612-5626. [PMID: 38959054 DOI: 10.1021/acs.jpca.4c02902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
The redox properties of the actinides in aqueous solution are important for fuel production/reprocessing and understanding the environmental impact of nuclear waste. The redox potentials for U, Np, Pu, and Am in oxidation states from 0 up to VII (as appropriate) in aqueous solutions have been predicted at the density functional theory level with the B3LYP functional, Stuttgart small core pseudopotential basis sets for the actinides, and explicit (30H2O molecules)/implicit treatment of the aqueous solvent using the self-consistent reaction field COSMO and SMD approaches for the implicit solvation. The predictions of the structural parameters of clusters incorporating first and second solvation shells are consistent with the available experimental data. Our results are typically within 0.2 V of the available experimental data using two explicit solvation shells with an implicit solvent model. The use of the PW91 functional substantially improved the prediction of the Pu(VI/V) redox couple. The redox couples for An(VI/IV) and An(V/IV) which involve the addition of protons and removal of the actinyl oxygens led to slightly larger differences from an experiment. The An(IV/0) and An(III/0) couples were reliably predicted with our approach. Predictions of the unknown An(II/I) redox potentials were negative, consistent with expectations, and predictions for unknown An(VII/VI), An(III/II), and An(II/0) redox couples improve prior estimates.
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Affiliation(s)
- Felipe R Dutra
- Instituto de Química, Universidade Estadual de Campinas, Barão Geraldo, P.O. Box 6154, Campinas 13083-970, São Paulo, Brazil
- Department of Chemistry and Biochemistry, The University of Alabama, Shelby Hall, Tuscaloosa, Alabama 35487-0336, United States
| | - Monica Vasiliu
- Department of Chemistry and Biochemistry, The University of Alabama, Shelby Hall, Tuscaloosa, Alabama 35487-0336, United States
| | - Amber N Gomez
- Department of Chemistry and Biochemistry, The University of Alabama, Shelby Hall, Tuscaloosa, Alabama 35487-0336, United States
| | - Donna Xia
- Department of Chemistry and Biochemistry, The University of Alabama, Shelby Hall, Tuscaloosa, Alabama 35487-0336, United States
| | - David A Dixon
- Department of Chemistry and Biochemistry, The University of Alabama, Shelby Hall, Tuscaloosa, Alabama 35487-0336, United States
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2
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Watanabe E, Nakajima T, Shinohara A, Kasamatsu Y. Hydration Structure of 102No 2+: A Density Functional Theory-Molecular Dynamics Study. J Phys Chem A 2024; 128:2717-2726. [PMID: 38563068 DOI: 10.1021/acs.jpca.3c08063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
The hydration structure of No2+, the divalent cation of nobelium in water, was investigated by ab initio molecular dynamics (MD) simulations. First, a series of benchmark calculations were performed to validate the density functional theory (DFT) calculation methods for a molecule containing a No atom. The DFT-MD simulation of the hydration structure of No2+ was conducted after the MD method was validated by simulating the hydration structures of Ca2+ and Sr2+, whose behavior was previously reported to be similar to that of No2+. The model cluster containing M2+ (M = Ca, Sr, or No) and 32 water molecules was used for DFT-MD simulation. The results showed that the hydration distance of No2+ was intermediate between those of Ca2+ and Sr2+. This trend in the hydration distance is in good agreement with the elution position trend obtained in a previous radiochemical experiment. The calculated No-O bond lengths in the optimized structure of [No(H2O)8]2+ was 2.59 Å, while the average No-O bond length of [No(H2O)8]2+ in water by DFT-MD was 2.55 Å. This difference implies the importance of dynamic solvent effects, considering the second (and further) coordination sphere in the theoretical calculation of solution chemistry for superheavy elements.
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Affiliation(s)
- Eisuke Watanabe
- Graduate School of Science, Osaka University, Machikaneyamacho 1-1, Toyonaka, Osaka 560-0043, Japan
- Nishina Accelerator-based Science Center, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
| | - Takahito Nakajima
- Center for Computational Science, RIKEN, Minatojimaminamimachi 7-1-26, Kobe, Hyogo 650-0047, Japan
| | - Atsushi Shinohara
- Institute for Radiation Sciences, Osaka University, Yamadaoka 2-4, Suita 565-0871, Japan
- Osaka Aoyama University, Niina 2-11-1, Minoh, Osaka 562-8580, Japan
| | - Yoshitaka Kasamatsu
- Graduate School of Science, Osaka University, Machikaneyamacho 1-1, Toyonaka, Osaka 560-0043, Japan
- Nishina Accelerator-based Science Center, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
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3
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Sachin AR, Gopakumar G, Brahmananda Rao CVS. Understanding the Complexation Behavior of Carbamoylphosphine Oxide Ligands with Representative f-Block Elements. J Phys Chem A 2024; 128:1085-1097. [PMID: 38294200 DOI: 10.1021/acs.jpca.3c07758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
The complexation behavior of carbamoylmethylphosphine oxide ligands (CMPO), a bifunctional phosphine oxide, and their substituted derivatives with Ce(III), Eu(III), Th(IV), U(VI), and Am(III) was probed at the density functional theory (DFT) level. The enhanced extraction of trivalent rare earth elements by the 2-diphenylphosphinylethyl derivative over the conventional CMPO ligand is identified due to the availability of an additional P═O donor group in the former. In addition, the orbital and dispersive interactions play a vital role in the preference of Th(IV) over U(VI) during extraction using CMPO ligands. The better complexing ability of ligands having long alkyl chain substituents at the P atom is justified due to the observed enhanced dispersion interactions in these systems.
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Affiliation(s)
- Aditya Ramesh Sachin
- Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamil Nadu, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Gopinadhanpillai Gopakumar
- Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamil Nadu, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Cherukuri Venkata Siva Brahmananda Rao
- Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamil Nadu, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
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4
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Parimi A, Mosher E, Schreckenbach G. Periodic trends in trivalent actinide halides, phosphates, and arsenates. Dalton Trans 2023; 52:18035-18044. [PMID: 37987618 DOI: 10.1039/d2dt02725a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Due to the limited abundance of the actinide elements, computational methods, for now, remain an exclusive avenue to investigate the periodic trends across the actinide series. As every actinide element can exhibit a +3-oxidation state, we have explored model systems of gas-phase actinide trihalides, phosphates, and arsenates across the series to capture the periodic trends. By doing so, we were able to capture the periodic trends down the halogen series as well, and for the first time we are reporting a study on actinide astatides. Using scalar and spin-orbit relativistic Density Functional Theory (DFT) calculations, we have explored the variations in bond lengths, bond angles, and the charges on actinides (An). Despite the use of different sets of ligands, the trends remain similar. The properties of trivalent Pa, U, Np, and Pu are nearly identical; similar ionic radii could be the reason. The actinide elements show a tendency to exhibit a pre-Pu and a post-Cm behaviour, with Am acting as a switch. This could be due to the change in the behaviour from d-f-type to f-filling/d-type at around Pu-Cm in the actinides as already proposed in the previous literature. Bond lengths in the AnX3 increase down the halide series, and the atomic charges decrease on the actinide elements.
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Affiliation(s)
- Ashutosh Parimi
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada.
| | - Emmalee Mosher
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada.
| | - Georg Schreckenbach
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada.
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5
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Jennifer G A, Gao Y, Schreckenbach G, Varathan E. Periodic Trends in the Stabilization of Actinyls in Their Higher Oxidation States Using Pyrrophen Ligands. Inorg Chem 2023; 62:6920-6933. [PMID: 37104857 DOI: 10.1021/acs.inorgchem.3c00022] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Owing to the prominent existence and unique chemistry of actinyls, their complexation with suitable ligands is of significant interest. The complexation of high-valent actinyl moieties (An = U, Np, Pu and Am) with the acyclic sal-porphyrin analogue called "pyrrophen" (L(1)) and its dimethyl derivative (L(2)) with four nitrogen and two oxygen donor atoms was studied using relativistic density functional theory. Based on the periodic trends, the [UVO2-L(1)/L(2)]1- complexes show shorter bond lengths and higher bond orders that increase across the series of pentavalent actinyl complexes mainly due to the localization of the 5f orbitals. Among the hexavalent complexes, the [UVIO2-L(1)/L(2)] complexes have the shortest bonds. Following the uranyl complex, due to the plutonium turn, the [AmVIO2-L(1)/L(2)] complexes exhibit comparable properties with those of the former. Charge analysis suggests the complexation to be facilitated through ligand-to-metal charge transfer (LMCT) mainly through σ donation. Thermodynamic feasibility of complexation was modeled using hydrated actinyl moieties in aqueous medium and was found to be spontaneous. The dimethylated pyrrophen (L(2)) shows higher magnitudes of thermodynamic parameters indicating increased feasibility compared to the unsubstituted ligand (L(1)). Energy decomposition analysis (EDA) along with extended transition-state-natural orbitals for chemical valence theory (ETS-NOCV) analysis shows that the dominant electrostatic contributions decrease across the series and are counteracted by Pauli repulsion. Slight but considerable covalency is provided to hexavalent actinyl complexes by orbital contributions; this was confirmed by molecular orbital (MO) analysis that suggests strong covalency in americyl (VI) complexes. In addition to the pentavalent and hexavalent actinyl moieties, heptavalent actinyl species of neptunyl, plutonyl, and americyl were studied. Beyond the influence of the charges, the geometric and electronic properties point to the stabilization of neptunyl (VII) in the pyrrophen ligand environment, while the others shift to a lower (+VI) and relatively stable OS on complexation.
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Affiliation(s)
- Abigail Jennifer G
- Department of Chemistry, SRM Institute of Science and Technology, Kattankulathur 603203, Tamil Nadu, India
| | - Yang Gao
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, China
- NHC Key Laboratory of Nuclear Technology Medical Transformation (Mianyang Central Hospital), Mianyang 621010, China
| | - Georg Schreckenbach
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Elumalai Varathan
- Department of Chemistry, SRM Institute of Science and Technology, Kattankulathur 603203, Tamil Nadu, India
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6
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Sunaga A, Tabata C, Yamamura T. Linearity and Chemical Bond of UO 22+ Revisited: A Comparison Study with UN 2 and UE 22+ (E = S, Se, and Te) Based on Relativistic Calculations. J Phys Chem A 2022; 126:8606-8617. [DOI: 10.1021/acs.jpca.2c05216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Ayaki Sunaga
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka 590-0494, Japan
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Chihiro Tabata
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka 590-0494, Japan
- Materials Sciences Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
| | - Tomoo Yamamura
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka 590-0494, Japan
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7
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Jiang H, Liu Z, He L, Chai Z, Wang D. The Speciation of Americium Cations in Neat Water Implicated from DFT Studies. Inorg Chem 2022; 61:13858-13867. [PMID: 35984920 DOI: 10.1021/acs.inorgchem.2c01805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The recent observed manipulatable redox potential of trivalent americium ion in the aqueous phase by modifying an electrode offers an alternative to accomplish the separation. In order to understand extensively the speciation of Am, which is the prerequisite to understanding the mechanism of the oxidation of Am, we conducted a density functional study to identify the potential species of Am in its tri-, tetra-, and pentavalent states in aqueous phase. Based on the speciation analysis, the calculations implicate a stepwise mechanism for the oxidation of hydrated Am(III), which predominantly exists in its hydrated monatomic cationic form (Am3+(aq)). The two sequential one-electron oxidation processes first produce AmO2+(aq), which may establish an equilibrium with Am4+(aq), and the AmO2+(aq) may then evolve to the dioxo americyl(V) ion. These results suggest the copresence of Am4+(aq) and AmO2+(aq), which builds a bridge for the conversion of americium ion from a monatomic ion to dioxo americyl(V).
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Affiliation(s)
- Hui Jiang
- School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Ziyi Liu
- School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Lei He
- School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Zhifang Chai
- State Key Laboratory of Radiation Medicine and Protection, and School for Radiological and Interdisciplinary Sciences (RAD-X), Soochow University, Suzhou 215123, China.,Multidisciplinary Initiative Center, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Dongqi Wang
- School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
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8
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Jennifer G A, Gao Y, Schreckenbach G, Varathan E. Chemical bonding in actinyl(V/VI) dipyriamethyrin complexes for the actinide series from americium to californium: a computational investigation. Dalton Trans 2022; 51:10006-10019. [PMID: 35703365 DOI: 10.1039/d2dt01142e] [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
The separation of minor actinides in their dioxocation (i.e., actinyl) form in high-valence oxidation states requires efficient ligands for their complexation. In this work, we evaluate the complexation properties of actinyls including americyl, curyl, berkelyl, and californyl in their pentavalent and hexavalent oxidation states with the dipyriamethyrin ligand (L) using density functional theory calculations. The calculated bond parameters show shorter AnOyl bonds with covalent character and longer An-N bonds with ionic character. The bonding between the actinyl cation and the ligand anion shows a flow of charges from the ligand to actinyl in all [AnV/VIO2-L]1-/0 complexes. However, across the series, backdonation of charges from the metal to the ligand becomes prominent and stabilizes the complexes. The thermodynamic parameters in the gas phase and solution suggest that the complex formation reaction is spontaneous for [CfV/VIO2-L]1-/0 complexes and spontaneous at elevated temperatures (>298.15 K) for all other complexes. Spin-orbit corrections have a quantitative impact while the overall trend remains the same. Energy decomposition analysis (EDA) reveals that the interaction between actinyl and the ligand is mainly due to electrostatic contributions that decrease from Am to Cf along with an increase in orbital contributions due to the backdonation of charges from the actinyl metal center to the ligand that greatly stabilizes the Cf complex. The repulsive Pauli energy contribution is observed to increase in the case of [AnVO2-L]1- complexes from Am to Cf while a decrease is observed among [AnVIO2-L]0 complexes, showing minimum repulsion in [CfVIO2-L]0 complex formation. Overall, the hexavalent actinyl complexes show greater stability (increasing from Am to Cf) than their pentavalent counterparts.
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Affiliation(s)
- Abigail Jennifer G
- Department of Chemistry, SRM Institute of Science and Technology, Kattankulathur, Chennai 603203, Tamil Nadu, India.
| | - Yang Gao
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada. .,Institut National de La Recherche Scientifique (INRS)-Centre Énergie Matériaux Télécommunications, Varennes, QC, J3X 1P7, Canada.,Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, China
| | - Georg Schreckenbach
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada.
| | - Elumalai Varathan
- Department of Chemistry, SRM Institute of Science and Technology, Kattankulathur, Chennai 603203, Tamil Nadu, India.
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9
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Cooper S, Kaltsoyannis N. Covalency in AnCl 2 (An = Th-No). Dalton Trans 2022; 51:5929-5937. [PMID: 35348160 DOI: 10.1039/d2dt00315e] [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
A potential connection has previously been proposed between the emergence of unexpected covalent behaviour in various transcurium complexes and the increasing stability of the +2 oxidation state in the later members of the actinide series. We recently used computational methods to study AnCl3, finding evidence for energy degeneracy driven covalency in the later actinides, and here present a comparative study of AnCl2. The An-Cl bond lengths of the latter divide into two data sets; Th-Np, Cm, Bk and Pu, Am, Cf-No. On average the An-Cl bond length decreases for both sets but, with significant increases between Np and Pu, and between Bk and Cf, unlike the former group (Pu, Am, Cf-No)Cl2 have significantly larger lengths than the corresponding trichlorides. Using a range of Natural Bond Orbital (NBO), Natural Resonance Theory (NRT) and Quantum Theory of Atoms In Molecules (QTAIM) metrics, the covalency of the dichloride bonds is analysed. We find that the first group of dichlorides are similar to their trichloride counterparts and possess significantly more covalent bonds than (Pu, Am, Cf-No)Cl2. We believe this change in covalent behaviour across the series for the dichlorides is due to a decreased involvement of the 6d orbital in the later elements (as a result of the f-d excitation energy exceeding the d-stabilisation energy of the actinide ions in question). Moreover, we find that unlike the trichlorides, where the QTAIM delocalisation index indicates that covalency plateaus/moderately increases, An-Cl covalency decreases across the second half of the series for AnCl2. We attribute this difference in behaviour to a lack of significant energy degeneracy driven covalency for the dichlorides, with the energy difference between the dichlorides' β 5f and 3p Natural Atomic Orbitals being larger than for the trichlorides. Hence we find it is not the presence of a stable +2 oxidation state, but instead the extent of energy matching between the actinide 5f orbitals and the ligand 3p, that drives covalency in the transcurium chlorides.
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Affiliation(s)
- Sophie Cooper
- Department of Chemistry, School of Natural Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
| | - Nikolas Kaltsoyannis
- Department of Chemistry, School of Natural Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
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10
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Pyrch M, Augustine L, Williams J, Mason SE, Forbes T. Use of vibrational spectroscopy to identify the formation of neptunyl-neptunyl interactions: A paired Density Functional Theory and Raman spectroscopy study. Dalton Trans 2022; 51:4772-4785. [DOI: 10.1039/d2dt00200k] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Abstract: Actinyl-Actinyl interactions (AAIs) occur in pentavalent actinide systems, particularly for Np(V), and lead to complex vibrational signals that are challenging to analyze and interpret. Previous studies have focused on...
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11
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Zhang P, Zou W, Zhang P, Hu S. Electronic Structures and Properties of Actinide‐Bimetal Compounds An
2
O
2
(An=Th to Cf) and U
2
E
2
(E=N, F, S). Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100444] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Peng Zhang
- School of Mathematics and Physics University of Science and Technology Beijing Beijing 100083 China
| | - Wen‐Li Zou
- Institute of Modern Physics Northwest University Xi'an 710127 China
| | - Ping Zhang
- Institute of Applied Physics and Computational Mathematics Haidian Beijing 100088 China
| | - Shu‐Xian Hu
- School of Mathematics and Physics University of Science and Technology Beijing Beijing 100083 China
- Beijing Computational Science Research Center Haidian Beijing 100193 China
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12
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Liu J, Cheng L. Relativistic coupled‐cluster and equation‐of‐motion coupled‐cluster methods. WIRES COMPUTATIONAL MOLECULAR SCIENCE 2021. [DOI: 10.1002/wcms.1536] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Junzi Liu
- Department of Chemistry The Johns Hopkins University Baltimore Maryland USA
| | - Lan Cheng
- Department of Chemistry The Johns Hopkins University Baltimore Maryland USA
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13
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Varathan E, Gao Y, Schreckenbach G. Computational Study of Actinyl Ion Complexation with Dipyriamethyrin Macrocyclic Ligands. J Phys Chem A 2021; 125:920-932. [PMID: 33476158 DOI: 10.1021/acs.jpca.0c08760] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Relativistic density functional theory has been employed to characterize [AnO2(L)]0/-1 complexes, where An = U, Np, Pu, and Am, and L is the recently reported hexa-aza porphyrin analogue, termed dipyriamethyrin, which contains six nitrogen donor atoms (four pyrrolic and two pyridine rings). Shorter axial (An═O) and longer equatorial (An-N) bond lengths are observed when going from AnVI to AnV. The actinide to pyrrole nitrogen bonds are shorter as compared to the bonds to the pyridine nitrogens; the former also play a dominant role in the formation of the actinyl (VI and V) complexes. Natural population analysis shows that the pyrrole nitrogen atoms in all the complexes carry higher negative charges than the pyridine nitrogens. Upon binding actinyl ions with the ligand a significant ligand-to-metal charge transfer takes place in all the actinyl (VI and V) complexes. The formation energy of the actinyl(VI,V) complexes in the gas-phase is found to decrease in the order of UO2L > PuO2L > NpO2L > AmO2L. This trend is consistent with results for the formation of complexes in dichloromethane solution. The calculated ΔG and ΔH values are negative for all the complexes. Energy decomposition analysis (EDA) indicates that the interactions between actinyl(V/VI) and ligand are mainly controlled by electrostatic components over covalent orbital interactions, and the covalent character gradually decreases from U to Am for both pentavalent and hexavalent actinyl complexes.
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Affiliation(s)
- Elumalai Varathan
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada
| | - Yang Gao
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada
| | - Georg Schreckenbach
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada
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14
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Andreadi N, Mitrofanov A, Matveev P, Volkova A, Kalmykov S. Heavy-Element Reactions Database (HERDB): Relativistic ab Initio Geometries and Energies for Actinide Compounds. Inorg Chem 2020; 59:13383-13389. [DOI: 10.1021/acs.inorgchem.0c01746] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Nikolai Andreadi
- Chemistry Department, Moscow State University, Leninskie Gory 1−3, Moscow 119991, Russia
| | - Artem Mitrofanov
- Chemistry Department, Moscow State University, Leninskie Gory 1−3, Moscow 119991, Russia
| | - Petr Matveev
- Chemistry Department, Moscow State University, Leninskie Gory 1−3, Moscow 119991, Russia
| | - Anna Volkova
- Chemistry Department, Moscow State University, Leninskie Gory 1−3, Moscow 119991, Russia
| | - Stepan Kalmykov
- Chemistry Department, Moscow State University, Leninskie Gory 1−3, Moscow 119991, Russia
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15
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Zhang P, Wang YX, Zhang P, Wang SA, Hu SX. Evaluation of Chemical Bonding in Actinyl(VI/V) Oxo-Crown-Ether Complexes for Actinide Series from Uranium to Curium. Inorg Chem 2020; 59:11953-11961. [PMID: 32806007 DOI: 10.1021/acs.inorgchem.0c00535] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The separation and management of nuclear waste is one of the problems that needs to be solved urgently, so finding a new radiation-proof and durable extractant to deal with nuclear waste is a difficult but desirable task. Since the successful isolation of the first pentavalent plutonium crown ether complex recently (Wang et al. CCS Chem. 2020, 2, 425-431), complexes with actinyl(V/VI) inserted into the cavity of 18-crown-6 ether (oxo-18C6), as well as their bonding character, need to be explored. Here we present a series of novel crown ether complexes containing actinyl(V/VI) and oxo-18C6 via computational prediction and analysis. On the basis of the calculations, actinyl(V/VI) are thermodynamically feasible and can be stabilized by oxo-18C6 ligand via six dative bonds between An ions and the oxo-18C6 O atoms in the "insertion" structure of [AnO2(18C6)]2+/+ complexes. The stability of actinyl(VI) species generally falls at minor actinides, ascribed to the reduced highest possible oxidation states of curium, which is mainly attributed to the mixing of bonding orbitals and non-bonding orbitals as well as the increase of occupation on partially 5f antibonding orbitals. It is found that the interactions between the actinyl(V/VI) and oxo-18C6 are mainly electronic interactions, with the well-known covalency contributions generally decreasing from uranium to curium due to energy degeneracy and spatial orbital contraction. This work would give a basic understanding of the coordination chemistry of actinyl(V/VI), which also provides inspirations on the design of new extractants for actinide separations.
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Affiliation(s)
- Peng Zhang
- Beijing Computational Science Research Center, Beijing 100193, China
| | - Ya-Xing Wang
- State Key Laboratory of Radiation Medicine and Protection, School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou 215123, China
| | - Ping Zhang
- Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
| | - Shu-Ao Wang
- State Key Laboratory of Radiation Medicine and Protection, School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou 215123, China
| | - Shu-Xian Hu
- Beijing Computational Science Research Center, Beijing 100193, China
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16
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Abstract
AbstractThe past decade has been very productive in the field of actinide (An) oxides containing high-valent An. Novel gas-phase experimental and an impressive number of theoretical studies have been performed, mostly on pure oxides or oxides extended with other ligands. The review covers the structural properties of molecular An oxides with high (An≥V) oxidation states. The presented compounds include the actinide dioxide cations [AnO2]+ and [AnO2]2+, neutral and ionic AnOx (x = 3–6), oxides with more than one An atom like neutral dimers, trimers and dimers from cation–cation interactions, as well as large U-oxide clusters observed very recently in the gaseous phase.
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