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Smiles DE, Batista ER, Booth CH, Clark DL, Keith JM, Kozimor SA, Martin RL, Minasian SG, Shuh DK, Stieber SCE, Tyliszczak T. The duality of electron localization and covalency in lanthanide and actinide metallocenes. Chem Sci 2020; 11:2796-2809. [PMID: 34084340 PMCID: PMC8157540 DOI: 10.1039/c9sc06114b] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 02/04/2020] [Indexed: 12/14/2022] Open
Abstract
Previous magnetic, spectroscopic, and theoretical studies of cerocene, Ce(C8H8)2, have provided evidence for non-negligible 4f-electron density on Ce and implied that charge transfer from the ligands occurs as a result of covalent bonding. Strong correlations of the localized 4f-electrons to the delocalized ligand π-system result in emergence of Kondo-like behavior and other quantum chemical phenomena that are rarely observed in molecular systems. In this study, Ce(C8H8)2 is analyzed experimentally using carbon K-edge and cerium M5,4-edge X-ray absorption spectroscopies (XAS), and computationally using configuration interaction (CI) calculations and density functional theory (DFT) as well as time-dependent DFT (TDDFT). Both spectroscopic approaches provide strong evidence for ligand → metal electron transfer as a result of Ce 4f and 5d mixing with the occupied C 2p orbitals of the C8H8 2- ligands. Specifically, the Ce M5,4-edge XAS and CI calculations show that the contribution of the 4f1, or Ce3+, configuration to the ground state of Ce(C8H8)2 is similar to strongly correlated materials such as CeRh3 and significantly larger than observed for other formally Ce4+ compounds including CeO2 and CeCl6 2-. Pre-edge features in the experimental and TDDFT-simulated C K-edge XAS provide unequivocal evidence for C 2p and Ce 4f covalent orbital mixing in the δ-antibonding orbitals of e2u symmetry, which are the unoccupied counterparts to the occupied, ligand-based δ-bonding e2u orbitals. The C K-edge peak intensities, which can be compared directly to the C 2p and Ce 4f orbital mixing coefficients determined by DFT, show that covalency in Ce(C8H8)2 is comparable in magnitude to values reported previously for U(C8H8)2. An intuitive model is presented to show how similar covalent contributions to the ground state can have different impacts on the overall stability of f-element metallocenes.
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Affiliation(s)
- Danil E Smiles
- Lawrence Berkeley National Laboratory Berkeley California 94720 USA
| | | | - Corwin H Booth
- Lawrence Berkeley National Laboratory Berkeley California 94720 USA
| | - David L Clark
- Los Alamos National Laboratory Los Alamos New Mexico 87545 USA
| | | | - Stosh A Kozimor
- Los Alamos National Laboratory Los Alamos New Mexico 87545 USA
| | | | | | - David K Shuh
- Lawrence Berkeley National Laboratory Berkeley California 94720 USA
| | | | - Tolek Tyliszczak
- Lawrence Berkeley National Laboratory Berkeley California 94720 USA
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Abstract
Over the past 25 years, magnetic actinide complexes have been the object of considerable attention, not only at the experimental level, but also at the theoretical one. Such systems are of great interest, owing to the well-known larger spin–orbit coupling for actinide ions, and could exhibit slow relaxation of the magnetization, arising from a large anisotropy barrier, and magnetic hysteresis of purely molecular origin below a given blocking temperature. Furthermore, more diffuse 5f orbitals than lanthanide 4f ones (more covalency) could lead to stronger magnetic super-exchange. On the other hand, the extraordinary experimental challenges of actinide complexes chemistry, because of their rarity and toxicity, afford computational chemistry a particularly valuable role. However, for such a purpose, the use of a multiconfigurational post-Hartree-Fock approach is required, but such an approach is computationally demanding for polymetallic systems—notably for actinide ones—and usually simplified models are considered instead of the actual systems. Thus, Density Functional Theory (DFT) appears as an alternative tool to compute magnetic exchange coupling and to explore the electronic structure and magnetic properties of actinide-containing molecules, especially when the considered systems are very large. In this paper, relevant achievements regarding DFT investigations of the magnetic properties of actinide complexes are surveyed, with particular emphasis on some representative examples that illustrate the subject, including actinides in Single Molecular Magnets (SMMs) and systems featuring metal-metal super-exchange coupling interactions. Examples are drawn from studies that are either entirely computational or are combined experimental/computational investigations in which the latter play a significant role.
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Chemey AT, Celis-Barros C, Huang K, Sperling JM, Windorff CJ, Baumbach RE, Graf DE, Páez-Hernández D, Ruf M, Hobart DE, Albrecht-Schmitt TE. Electronic, Magnetic, and Theoretical Characterization of (NH4)4UF8, a Simple Molecular Uranium(IV) Fluoride. Inorg Chem 2018; 58:637-647. [DOI: 10.1021/acs.inorgchem.8b02800] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Alexander T. Chemey
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Cristian Celis-Barros
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Kevin Huang
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32306, United States
| | - Joseph M. Sperling
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Cory J. Windorff
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Ryan E. Baumbach
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32306, United States
- Department of Physics, Florida State University, Tallahassee, Florida 32306, United States
| | - David E. Graf
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32306, United States
| | - Dayán Páez-Hernández
- Centro de Nanociencias Aplicadas, Facultad de Ciencias Exactas, Universidad Andrés Bello, Republica 275, Santiago, Chile
| | - Michael Ruf
- Bruker AXS, 5465 East Cheryl Parkway, Madison, Wisconsin 53711, United States
| | - David E. Hobart
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Thomas E. Albrecht-Schmitt
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
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Edelmann FT. Lanthanides and actinides: Annual survey of their organometallic chemistry covering the year 2017. Coord Chem Rev 2018. [DOI: 10.1016/j.ccr.2018.05.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Solis-Céspedes E, Montenegro-Pohlhammer N, Páez-Hernández D. Theoretical insight into the superexchange mechanism of coupling in f1-f1 system. The case of study Ce2(COT)3 compound. Inorganica Chim Acta 2018. [DOI: 10.1016/j.ica.2018.03.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Beltrán-Leiva MJ, Cantero-López P, Zúñiga C, Bulhões-Figueira A, Páez-Hernández D, Arratia-Pérez R. Theoretical Method for an Accurate Elucidation of Energy Transfer Pathways in Europium(III) Complexes with Dipyridophenazine (dppz) Ligand: One More Step in the Study of the Molecular Antenna Effect. Inorg Chem 2017; 56:9200-9208. [DOI: 10.1021/acs.inorgchem.7b01221] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- María J. Beltrán-Leiva
- Relativistic Molecular Physics (ReMoPh) Group, Ph.D. Program in Molecular
Physical Chemistry, Universidad Andrés Bello, Av. República 275, Santiago 8370146, Chile
| | - Plinio Cantero-López
- Relativistic Molecular Physics (ReMoPh) Group, Ph.D. Program in Molecular
Physical Chemistry, Universidad Andrés Bello, Av. República 275, Santiago 8370146, Chile
| | - César Zúñiga
- Centro de Nanociencias
Aplicadas, Facultad de Ciencias Exactas, Universidad Andrés Bello, Av. República 275, Santiago 8370146, Chile
| | - Ana Bulhões-Figueira
- Centro Universitário Estácio de Ribeirão Preto, Rua Abrahão Issa Halach, 980 Ribeirânia, Ribeirão Preto, Sao Paulo 14096-160, Brazil
| | - Dayán Páez-Hernández
- Relativistic Molecular Physics (ReMoPh) Group, Ph.D. Program in Molecular
Physical Chemistry, Universidad Andrés Bello, Av. República 275, Santiago 8370146, Chile
- Centro de Nanociencias
Aplicadas, Facultad de Ciencias Exactas, Universidad Andrés Bello, Av. República 275, Santiago 8370146, Chile
| | - Ramiro Arratia-Pérez
- Relativistic Molecular Physics (ReMoPh) Group, Ph.D. Program in Molecular
Physical Chemistry, Universidad Andrés Bello, Av. República 275, Santiago 8370146, Chile
- Centro de Nanociencias
Aplicadas, Facultad de Ciencias Exactas, Universidad Andrés Bello, Av. República 275, Santiago 8370146, Chile
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