Perplexing EPR Signals from 5f36d1 U(II) Complexes

Metal complexes with unpaired electrons in orbitals of different angular momentum quantum numbers (e.g., f and d orbitals) are unusual and opportunities to study the interactions among these electrons are rare. X-band electron paramagnetic resonance (EPR) data were collected at <10 and 77 K on 10 U(II) complexes with 5f36d1 electron configurations and on some analogous Ce(II), Pr(II), and Nd(II) complexes with 4fn5d1 electron configurations. The U(II) compounds unexpectedly display similar two-line axial signals with g|| = 2.04 and g⊥ = 2.00 at 77 K. In contrast, U(II) complexes with 5f4 configurations are EPR-silent. Unlike U(II), the congenic 4f35d1 Nd(II) complex is EPR-silent. The Ce(II) complex with a 4f15d1 configuration is also EPR-silent, but a signal is observed for the Pr(II) complex, which has a 4f25d1 configuration. Whether or not an EPR signal is expected for these complexes depends on the coupling between f and d electrons. Since the coupling in U(II) systems is expected to be sufficiently strong to preclude an EPR signal from compounds with a 5f36d1 configuration, the results are viewed as unexplained phenomena. However, they do show that 5f36d1 U(II) samples can be differentiated from 5f4 U(II) complexes by EPR spectroscopy.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:63

Enthalten in:

Inorganic chemistry - 63(2024), 6 vom: 12. Feb., Seite 2945-2953

Sprache:

Englisch

Beteiligte Personen:

Wedal, Justin C [VerfasserIn]
Moore, William N G [VerfasserIn]
Lukens, Wayne W [VerfasserIn]
Evans, William J [VerfasserIn]

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Journal Article

Anmerkungen:

Date Revised 12.02.2024

published: Print-Electronic

Citation Status PubMed-not-MEDLINE

doi:

10.1021/acs.inorgchem.3c03449

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM367696134