Relativistic All‐Electron Approaches to the Study of f Element Chemistry

Saue, Trond; Visscher, Lucas

doi:10.1002/9781118688304.ch3

Cited by 10 publications

(7 citation statements)

References 76 publications

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“…44 As it is well known, the energetic stabilization and radial contraction of the 5f shell across the An series comes from the increasing effective nuclear charge experienced by the 5f shell because of the incomplete nuclear screening among same-shell electrons. 6,147 The 5f contraction necessarily causes decreasing 5f-shell overlap with ligand orbitals along the series. However, it is worth noting that from U to Am, the overlap remains substantial.…”

Section: Resultsmentioning

confidence: 99%

Covalency of Trivalent Actinide Ions with Different Donor Ligands: Do Density Functional and Multiconfigurational Wavefunction Calculations Corroborate the Observed “Breaks”?

Sergentu

Feng

et al. 2021

Inorg. Chem.

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A comprehensive ab initio study of periodic actinide−ligand bonding trends for trivalent actinides is performed. Relativistic density functional theory (DFT) and complete activespace (CAS) self-consistent field wavefunction calculations are used to dissect the chemical bonding in the [AnCl 6 ] 3− , [An-(CN) 6 ] 3− , [An(NCS) 6 ] 3− , [An(S 2 PMe 2 ) 3 ], [An(DPA) 3 ] 3− , and [An(HOPO)] − series of actinide (An = U−Es) complexes. Except for some differences for the early actinide complexes with DPA, bond orders and excess 5f-shell populations from donation bonding show qualitatively similar trends in 5f n active-space CAS vs DFT calculations. The influence of spin−orbit coupling on donation bonding is small for the tested systems. Along the actinide series, chemically soft vs chemically harder ligands exhibit clear differences in bonding trends. There are pronounced changes in the 5f populations when moving from Pu to Am or Cm, which correlate with previously noted "breaks" in chemical trends. Bonding involving 5f becomes very weak beyond Cm/Bk. We propose that Cm(III) is a borderline case among the trivalent actinides that can be meaningfully considered to be involved in ground-state 5f covalent bonding.

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Section: Resultsmentioning

confidence: 99%

Covalency of Trivalent Actinide Ions with Different Donor Ligands: Do Density Functional and Multiconfigurational Wavefunction Calculations Corroborate the Observed “Breaks”?

Sergentu

Feng

et al. 2021

Inorg. Chem.

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“…We additionally correlate the magnitude of this repulsion with the radial distribution of the 4f- versus 5d-orbitals. Because the 4f-orbitals are closer to the nucleus, 31 increased 4f-orbital occupancy destabilizes the core 2p-orbital energies to a large extent. Meanwhile, occupancy of the more diffuse 5d-orbitals has less impact on the 2p-orbital energies.…”

Section: Resultsmentioning

confidence: 99%

Evaluating the electronic structure of formal Ln^IIions in Ln^II(C₅H₄SiMe₃)₃¹⁻using XANES spectroscopy and DFT calculations

Fieser

Ferrier

et al. 2017

Chem. Sci.

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“…Current DFT methods are thus unlikely to be sufficiently reliable and informative when applied to lanthanoid compounds, where an appropriate description of the interplay between strong electron correlation (multireference character) and nonperturbative relativistic effects ( i.e. , strong spin–orbit coupling) is of the essence to build reliable models, even at a qualitative level . Arguably, the description of LMCT transitions in lanthanoid complexes represents an even more challenging computational task than that of 4f-multiplet excitations, due to the need to provide a suitable description of the interactions between states that are widely different in nature, i.e.…”

Section: Introductionmentioning

confidence: 99%

“…However, the modeling of a transition to a LMCT state has remained a significant challenge because it requires an accurate description of both the ground state, which is usually a magnetic level and the LMCT excited state, which involves a change of (oxidation) state for the metal and one or more ligands. For this reason, while several multireference ab initio studies of 4f–4f excitations in lanthanoid complexes ,− and 4f–5d transitions in doped glasses − have been reported, ab initio studies of LMCT remain scarce in the literature due to their complexity. , This work sets a foundational framework based on both theoretical and solid-state experimental approaches to investigate LMCT excited states for lanthanoid complexes.…”

Section: Introductionmentioning

confidence: 99%

Elucidation of LMCT Excited States for Lanthanoid Complexes: A Theoretical and Solid-State Experimental Framework

et al. 2022

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Photophysical and magnetic properties arising from both ground and excited states of lanthanoid ions are relevant for numerous applications. These properties can be substantially affected, both adversely and beneficially, by ligand-tometal charge-transfer (LMCT) states. However, probing LMCT states remains a significant challenge in f-block chemistry, particularly in the solid state. Intriguingly, the europium compounds [Eu III (18-c-6)(X 4 Cat)(NO 3 )]•MeCN (18-c-6 = 18-crown-6; X = Cl (tetrachlorocatecholate, 1-Eu) or Br (tetrabromocatecholate, 2-Eu) are distinctly darkly-colored, in marked contrast to the analogues with other lanthanoid ions in the 1-Ln and 2-Ln series (Ln = La, Ce, Nd, Gd, Tb, and Dy). Herein, we report a multitechnique investigation of these compounds that has allowed elucidation of the LMCT character of the relevant absorption bands using magnetometry, absorption and emission spectroscopies, and solid-state electrochemistry. To support experimental observations, we present a semi-quantitative multireference ab initio model that (i) captures the anomalously low-lying LMCT excited state observed in the visible spectrum of 1-Eu (and its absence in the other 1-Ln analogues); (ii) elucidates the contribution of the LMCT excitation to the crystal field split 7 F J ground-state wave functions; and (iii) identifies the crucial role played by radial dynamical correlation of the Eu III 4f electrons in the description of the LMCT excited state, modeled by the inclusion of 4f → 5f excitations in the optimized wave function. By providing a set of experimental and theoretical tools, this work establishes a framework for the elucidation of LMCT excited states in lanthanoid compounds in the solid state.

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Relativistic All‐Electron Approaches to the Study of f Element Chemistry

Cited by 10 publications

References 76 publications

Covalency of Trivalent Actinide Ions with Different Donor Ligands: Do Density Functional and Multiconfigurational Wavefunction Calculations Corroborate the Observed “Breaks”?

Covalency of Trivalent Actinide Ions with Different Donor Ligands: Do Density Functional and Multiconfigurational Wavefunction Calculations Corroborate the Observed “Breaks”?

Evaluating the electronic structure of formal Ln^IIions in Ln^II(C₅H₄SiMe₃)₃¹⁻using XANES spectroscopy and DFT calculations

Elucidation of LMCT Excited States for Lanthanoid Complexes: A Theoretical and Solid-State Experimental Framework

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Relativistic All‐Electron Approaches to the Study of f Element Chemistry

Cited by 10 publications

References 76 publications

Covalency of Trivalent Actinide Ions with Different Donor Ligands: Do Density Functional and Multiconfigurational Wavefunction Calculations Corroborate the Observed “Breaks”?

Covalency of Trivalent Actinide Ions with Different Donor Ligands: Do Density Functional and Multiconfigurational Wavefunction Calculations Corroborate the Observed “Breaks”?

Evaluating the electronic structure of formal LnIIions in LnII(C5H4SiMe3)31−using XANES spectroscopy and DFT calculations

Elucidation of LMCT Excited States for Lanthanoid Complexes: A Theoretical and Solid-State Experimental Framework

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Evaluating the electronic structure of formal Ln^IIions in Ln^II(C₅H₄SiMe₃)₃¹⁻using XANES spectroscopy and DFT calculations