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Autillo M, Illy MC, Briscese L, Islam MA, Bolvin H, Berthon C. Paramagnetic Properties of [An IV(NO 3) 6] 2- Complexes (An = U, Np, Pu) Probed by NMR Spectroscopy and Quantum Chemical Calculations. Inorg Chem 2024. [PMID: 38951989 DOI: 10.1021/acs.inorgchem.4c01694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/03/2024]
Abstract
Actinide +IV complexes with six nitrates [AnIV(NO3)6]2- (An = Th, U, Np, and Pu) have been studied by 15N and 17O NMR spectroscopy in solution and first-principles calculations. Magnetic susceptibilities were evaluated experimentally using the Evans method and are in good agreement with the ab initio values. The evolution in the series of the crystal field parameters deduced from ab initio calculations is discussed. The NMR paramagnetic shifts are analyzed based on ab initio calculations. Because the cubic symmetry of the complex quenches the dipolar contribution, they are only of Fermi contact origin. They are evaluated from first-principles based on a complete active space/density functional theory (DFT) strategy, in good accordance with the experimental one. The ligand hyperfine coupling constants are deduced from paramagnetic shifts and calculated using unrestricted DFT. The latter are decomposed in terms of the contribution of molecular orbitals. It highlights two pathways for the delocalization of the spin density from the metallic open-shell 5f orbitals to the NMR active nuclei, either through the valence 5f hybridized with 6d to the valence 2p molecular orbitals of the ligands, or by spin polarization of the metallic 6p orbitals which interact with the 2s-based molecular orbitals of the ligands.
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Affiliation(s)
- Matthieu Autillo
- CEA, DES, ISEC, DPME, Univ. Montpellier, Bagnols-sur-Cèze 30207, France
| | - Marie-Claire Illy
- CEA, DES, ISEC, DMRC, Univ. Montpellier, Bagnols-sur-Cèze 30207, France
| | - Luca Briscese
- CEA, DES, ISEC, DMRC, Univ. Montpellier, Bagnols-sur-Cèze 30207, France
| | - Md Ashraful Islam
- Centre de Résonance Magnétique Nucléaire à Très Hauts Champs─CRMN, 5 Rue de la Doua, 69100 Villeurbanne, France
| | - Hélène Bolvin
- Laboratoire de Chimie et Physique Quantiques, CNRS, Université Toulouse III, 118 route de Narbonne, 31062 Toulouse, France
| | - Claude Berthon
- CEA, DES, ISEC, DMRC, Univ. Montpellier, Bagnols-sur-Cèze 30207, France
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Islam MA, Berthon C, Jung J, Bolvin H. Bonding and Magnetic Trends in the [An III(DPA) 3] 3- Series Compared to the Ln(III) and An(IV) Analogues. Inorg Chem 2023; 62:17254-17264. [PMID: 37818639 DOI: 10.1021/acs.inorgchem.3c02482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/12/2023]
Abstract
The crystal field parameters are determined from first-principles calculations in the [AnIII(DPA)3]3- series, completing previous work on the [LnIII(DPA)3]3- and [AnIV(DPA)3]2- series. The crystal field strength parameter follows the Ln(III) < An(III) < An(IV) trend. The parameters deduced at the orbital level decrease along the series, while J-mixing strongly impacts the many-electron parameters, especially for the Pu(III) complex. We further compile the available data for the three series. In some aspects, An(III) complexes are closer to Ln(III) than to An(IV) complexes with regard to the geometrical structure and bonding descriptors. At the beginning of the series, up to Pu(III), there is a quantitative departure from the free ion, especially for the Pa(III) complex. The magnetic properties of the actinides keep the trends of the lanthanides; in particular, the axial magnetic susceptibility follows Bleaney's theory qualitatively.
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Affiliation(s)
- Md Ashraful Islam
- Laboratoire de Chimie et Physique Quantiques, CNRS, Université Toulouse III, 118 Route de Narbonne, 31062 Toulouse, France
| | - Claude Berthon
- CEA, DES, ISEC, DMRC, Univ Montpellier, Marcoule, 30207 Bagnols-sur-Cèze, France
| | - Julie Jung
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Hélène Bolvin
- Laboratoire de Chimie et Physique Quantiques, CNRS, Université Toulouse III, 118 Route de Narbonne, 31062 Toulouse, France
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Koppe J, Pell AJ. Structure Determination and Refinement of Paramagnetic Materials by Solid-State NMR. ACS PHYSICAL CHEMISTRY AU 2023; 3:419-433. [PMID: 37780542 PMCID: PMC10540298 DOI: 10.1021/acsphyschemau.3c00019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 06/08/2023] [Accepted: 06/08/2023] [Indexed: 10/03/2023]
Abstract
Paramagnetism in solid-state materials has long been considered an additional challenge for structural investigations by using solid-state nuclear magnetic resonance spectroscopy (ssNMR). The strong interactions between unpaired electrons and the surrounding atomic nuclei, on the one hand, are complex to describe, and on the other hand can cause fast decaying signals and extremely broad resonances. However, significant progress has been made over the recent years in developing both theoretical models to understand and calculate the frequency shifts due to paramagnetism and also more sophisticated experimental protocols for obtaining high-resolution ssNMR spectra. While the field is continuously moving forward, to date, the combination of state-of-the-art numerical and experimental techniques enables us to obtain high-quality data for a variety of systems. This involves the determination of several ssNMR parameters that represent different contributions to the frequency shift in paramagnetic solids. These contributions encode structural information on the studied material on various length scales, ranging from crystal morphologies, to the mid- and long-range order, down to the local atomic bonding environment. In this perspective, the different ssNMR parameters characteristic for paramagnetic materials are discussed with a focus on their interpretation in terms of structure. This includes a summary of studies that have explored the information content of these ssNMR parameters, mostly to complement experimental data from other methods, e.g., X-ray diffraction. The presented overview aims to demonstrate how far ssNMR has hitherto been able to determine and refine the structures of materials and to discuss where it currently falls short of its full potential. We attempt to highlight how much further ssNMR can be pushed to determine and refine structure to deliver a comprehensive structural characterization of paramagnetic materials comparable to what is to date achieved by the combined effort of electron microscopy, diffraction, and spectroscopy.
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Affiliation(s)
- Jonas Koppe
- Centre
de RMN à Très Hauts Champs de Lyon (UMR 5082 −
CNRS, ENS Lyon, UCB Lyon 1), Université de Lyon, 5 Rue de la Doua, 69100 Villeurbanne, France
| | - Andrew J. Pell
- Centre
de RMN à Très Hauts Champs de Lyon (UMR 5082 −
CNRS, ENS Lyon, UCB Lyon 1), Université de Lyon, 5 Rue de la Doua, 69100 Villeurbanne, France
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Islam MA, Autillo M, Poulin-Ponnelle C, Tamain C, Bolvin H, Berthon C. Are Actinyl Cations Good Probes for Structure Determination in Solution by NMR? Inorg Chem 2023. [PMID: 37368989 DOI: 10.1021/acs.inorgchem.3c00536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
We report on NMR spectroscopy, CAS-based method calculations, and X-ray diffraction of AnV and AnVI complexes with a neutral and slightly flexible TEDGA ligand. After checking that pNMR shifts mainly arise from pseudocontact interactions, we analyze pNMR shifts considering the axial and rhombic anisotropy of the actinyl magnetic susceptibilities. The results are compared to those of a previous study performed on [AnVIO2]2+ complexes with dipicolinic acid. It is shown that 5f2 cations (PuVI and NpV) make very good candidates for determining the structure of actinyl complexes in solution by 1H NMR spectroscopy as shown by the invariance of the magnetic properties to the equatorial ligands, as opposed to the NpVI complexes with a 5f1 configuration.
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Affiliation(s)
- Md Ashraful Islam
- Laboratoire de Chimie et Physique Quantiques, CNRS, Université Toulouse III, 118 route de Narbonne, 31062 Toulouse, France
| | - Matthieu Autillo
- CEA, DES, ISEC, DMRC, Univ. Montpellier, Bagnols sur Cèze 30207, France
| | | | - Christelle Tamain
- CEA, DES, ISEC, DMRC, Univ. Montpellier, Bagnols sur Cèze 30207, France
| | - Hélène Bolvin
- Laboratoire de Chimie et Physique Quantiques, CNRS, Université Toulouse III, 118 route de Narbonne, 31062 Toulouse, France
| | - Claude Berthon
- CEA, DES, ISEC, DMRC, Univ. Montpellier, Bagnols sur Cèze 30207, France
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Poulin-Ponnelle C, Duvail M, Dumas T, Berthon C. Contribution of Molecular Dynamics in pNMR for the Structural Determination of An V and An VI Complexes in Solution. Inorg Chem 2022; 61:15895-15909. [PMID: 36166623 DOI: 10.1021/acs.inorgchem.2c02040] [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
In this study, we propose to use classical molecular dynamics (MD) coupled with 1H NMR spectroscopy to study the conformations of different actinyl AnVI (An = U, Np, and Pu) and AnV (An = Np) complexes with tetra-ethyl dyglicolamide (TEDGA) ligands in order to have a better representation of such complexes in solution. Molecular dynamics simulations showed its effectiveness in interpreting the experiments by the calculation of geometric factors needed for the determination of magnetic properties of these complexes. We demonstrated that different conformations of the AnV and AnVI complexes with TEDGA exist in solution with different coordination modes, which is experimentally confirmed by 1H NMR and EXAFS spectroscopies. Furthermore, MD simulations provide additional insights into the structures of complexes in solution since conformations with fast exchanges, which are not accessible from NMR experiments, have been observed by MD simulations.
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Affiliation(s)
| | - Magali Duvail
- ICSM, Univ. Montpellier, CEA, CNRS, ENSCM, Bagnols sur Cèze 30207, France
| | - Thomas Dumas
- LILA, Univ. Montpellier, CEA, Bagnols sur Cèze 30207, France
| | - Claude Berthon
- LILA, Univ. Montpellier, CEA, Bagnols sur Cèze 30207, France
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Islam MA, Autillo M, Guérin L, Tamain C, Moisy P, Bolvin H, Berthon C. Dipolar and Contact Paramagnetic NMR Chemical Shifts in An IV Complexes with Dipicolinic Acid Derivatives. Inorg Chem 2022; 61:10329-10341. [PMID: 35749686 DOI: 10.1021/acs.inorgchem.2c00845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Actinide +IV complexes (AnIV = ThIV, UIV, NpIV, and PuIV) with two dipicolinic acid derivatives (DPA and Et-DPA) have been studied by 1H and 13C NMR spectroscopies and first-principles calculations. The Fermi contact and dipolar contributions to the actinide-induced shifts (AIS) are evaluated from a temperature dependence analysis, combined with ab initio results. It allows an experimental estimation of the axial anisotropy of the magnetic susceptibility Δχax and of the hyperfine coupling constants of the NMR-active nuclei. Due to the compactness of the coordination sphere, the magnetic anisotropy of the paramagnetic center is small, and this makes the contact contribution to be the dominant one, even on the remote atoms. The sign of the hyperfine coupling constants and related spin densities is alternating on the nuclei of the ligand cycle, denoting a preponderant spin polarization mechanism. This is well reproduced by unrestricted density functional theory (DFT) calculations. Those values are furthermore slightly decreasing in the actinide series, which indicates a small decrease of the covalency from UIV to PuIV.
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Affiliation(s)
- Md Ashraful Islam
- Laboratoire de Chimie et Physique Quantiques, CNRS, Université Toulouse III, 118 Route de Narbonne, 31062 Toulouse, France
| | | | - Laetitia Guérin
- CEA, DES, ISEC, DMRC, Univ. Montpellier, Marcoule 30207, France
| | | | - Philippe Moisy
- CEA, DES, ISEC, DMRC, Univ. Montpellier, Marcoule 30207, France
| | - Hélène Bolvin
- Laboratoire de Chimie et Physique Quantiques, CNRS, Université Toulouse III, 118 Route de Narbonne, 31062 Toulouse, France
| | - Claude Berthon
- CEA, DES, ISEC, DMRC, Univ. Montpellier, Marcoule 30207, France
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