Zur Elektronenstruktur metallorganischer Komplexe der f-Elemente

Schulz, Hans‐Joachim; Reddmann, Hauke; Amberger, H.‐D.; Kanellakopulos, Β.; Apostolidis, Christos; Rébizant, J.; Edelstein, Norman M.

doi:10.1016/s0022-328x(00)00854-8

Cited by 23 publications

(14 citation statements)

References 28 publications

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“…The highest and lowest-lying-orbitals are unchanged upon coordination of the ligand; however, the total splitting of the f-orbitals is decreased as previously observed for (C 5 H 5 ) 3 Nd isocyanide adducts. 19 Both experimentally and computationally, coordination of the isocyanide ligand does not greatly destabilize the f z 3 orbital relative to 1 and does not stabilize the (f xz 2 ,f yz 2 )-orbitals that could interact with the π*-orbital of the ligand in agreement with the SOMOs illustrated in Figure 1. However, the splitting of the f-orbitals reflects the anisotropy of their interactions with ligands as well as the strength of those interactions (a spherically symmetric crystal field does not split the orbitals regardless of the strength of the interaction).…”

Section: Cp" 3 Nd•l (2 and 3)mentioning

confidence: 72%

“…10 Common approaches to studying bonding in actinides and lanthanides are comparing ions with either similar ionic radii, e.g., Ce(III) vs U(III), or similar electronic structures, e.g., Nd(III) vs U(III). 14,16,18,19 The role of this orbital in bonding may also be observed by photoelectron spectroscopy although the effect is more pronounced in the Cp 3 M + molecular cations. More recently, the relative energies of the ligand and metal-orbitals have received increased attention due to their roles in increasing covalency by "accidental degeneracy" (increased covalency due to the similar ligand and metal-orbital energies).…”

Section: Introductionmentioning

confidence: 93%

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The roles of 4f- and 5f-orbitals in bonding: a magnetochemical, crystal field, density functional theory, and multi-reference wavefunction study

et al. 2016

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The electronic structures of 4f(3)/5f(3) Cp''3M and Cp''3M·alkylisocyanide complexes, where Cp'' is 1,3-bis-(trimethylsilyl)cyclopentadienyl, are explored with a focus on the splitting of the f-orbitals, which provides information about the strengths of the metal-ligand interactions. While the f-orbital splitting in many lanthanide complexes has been reported in detail, experimental determination of the f-orbital splitting in actinide complexes remains rare in systems other than halide and oxide compounds, since the experimental approach, crystal field analysis, is generally significantly more difficult for actinide complexes than for lanthanide complexes. In this study, a set of analogous neodymium(iii) and uranium(iii) tris-cyclopentadienyl complexes and their isocyanide adducts was characterized by electron paramagnetic resonance (EPR) spectroscopy and magnetic susceptibility. The crystal field model was parameterized by combined fitting of EPR and susceptibility data, yielding an accurate description of f-orbital splitting. The isocyanide derivatives were also studied using density functional theory, resulting in f-orbital splitting that is consistent with crystal field fitting, and by multi-reference wavefunction calculations that support the electronic structure analysis derived from the crystal-field calculations. The results highlight that the 5f-orbitals, but not the 4f-orbitals, are significantly involved in bonding to the isocyanide ligands. The main interaction between isocyanide ligand and the metal center is a σ-bond, with additional 5f to π* donation for the uranium complexes. While interaction with the isocyanide π*-orbitals lowers the energies of the 5fxz(2) and 5fyz(2)-orbitals, spin-orbit coupling greatly reduces the population of 5fxz(2) and 5fyz(2) in the ground state.

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Section: Cp" 3 Nd•l (2 and 3)mentioning

confidence: 72%

Section: Introductionmentioning

confidence: 93%

The roles of 4f- and 5f-orbitals in bonding: a magnetochemical, crystal field, density functional theory, and multi-reference wavefunction study

et al. 2016

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“…Theoretically, in the case of lower membered aromatic ligands such as Cp, the actual C 5v symmetry of the [Sm (Cp)] 2ϩ moiety has to be considered. However, a number of previous studies of ψ trigonal pyramidal [39] and ψ trigonal bipyramidal [40] Cp complexes of rare earths showed that the fivemembered Cp rings disturb the pseudo symmetry only weakly. Therefore, in the framework of this approach instead of the actual molecular C 5v the higher C ϱv symmetry is assumed.…”

Section: General Symmetry Considerations Selection Rules and The Phementioning

confidence: 94%

Crystal Field Strengths, Nephelauxetic Effects, and Experimentally Based Molecular Orbital Schemes (in the f Range) of Selected Cyclopentadienyl Complexes of Samarium(III)

et al. 2003

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The absorption and luminescence spectra of pseudo (ψ) trigonal planar [Sm(η5‐C5H4tBu)3] (1), low symmetric [Sm(η5‐Cp)(η3‐Tp)(η2‐Tp)] (Cp = η5‐cyclopentadienyl; Tp = hydrotris(3,5‐dimethylpyrazolyl)borato) (2) as well as ψ trigonal pyramidal [Sm(η5‐C5H4tBu)3(THF)] (3), [Sm(η5‐Cp)3(THF)] (4) and [Sm(η5‐Cp)3(CNC6H11)] (5) have been measured at room and low temperatures. From the spectra obtained, truncated crystal field (CF) splitting patterns of these compounds could be derived, and simulated by fitting the parameters of a phenomenological Hamiltonian. On the basis of the CF parameters used, the global CF strengths experienced by the Sm3+ central ions of complexes 1−5, as well as the individual CF strength associated with one C5H4tBu− ligand are estimated. The obtained Slater parameters F2 and the spin‐orbit coupling parameters ζ4f allow the insertion of compounds 1−5 into truncated nephelauxetic and relativistic nephelauxetic series. Besides, the experimentally based non‐relativistic and relativistic molecular orbital schemes (in the f range) of complexes 1 and, partly, 3 are set up and compared with the results of quantum chemical model calculations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

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“…[10][11][12][13] In addition, a large number of studies have examined the coupling between f-ions and adjacent paramagnetic transition metals or organic radicals. 1,[14][15][16][17][18][19][20][21][22][23][24][25][26][27] Two factors make it challenging to quantify f-electron coupling. First, the magnetic moments of f-ions, except for f 7 -systems, are temperature dependent and highly anisotropic due to a combination of strong spin-orbit coupling and weak crystal fields.…”

Section: Introductionmentioning

confidence: 99%

Quantifying Exchange Coupling in f-Ion Pairs Using the Diamagnetic Substitution Method

Lukens

Walter

2010

Inorg. Chem.

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One of the challenges in the chemistry of actinide and lanthanide (f-ion) is quantifying exchange coupling between f-ions. While qualitative information about exchange coupling may be readily obtained using the diamagnetic substitution approach, obtaining quantitative information is much more difficult. This article describes how exchange coupling may be quantified using the susceptibility of a magnetically isolated analog, as in the diamagnetic substitution approach, along with the anisotropy of the ground state as determined by EPR spectroscopy. Several examples are used to illustrate and test this approach.

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Zur Elektronenstruktur metallorganischer Komplexe der f-Elemente

Cited by 23 publications

References 28 publications

The roles of 4f- and 5f-orbitals in bonding: a magnetochemical, crystal field, density functional theory, and multi-reference wavefunction study

The roles of 4f- and 5f-orbitals in bonding: a magnetochemical, crystal field, density functional theory, and multi-reference wavefunction study

Crystal Field Strengths, Nephelauxetic Effects, and Experimentally Based Molecular Orbital Schemes (in the f Range) of Selected Cyclopentadienyl Complexes of Samarium(III)

Quantifying Exchange Coupling in f-Ion Pairs Using the Diamagnetic Substitution Method

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