[UF6 ]2- : A Molecular Hexafluorido Actinide(IV) Complex with Compensating Spin and Orbital Magnetic Moments

Kasper S Pedersen; Katie R Meihaus; Andrei Rogalev; Fabrice Wilhelm; Daniel Aravena; Martín Amoza; Eliseo Ruiz; Jeffrey R Long; Jesper Bendix; Rodolphe Clérac

doi:10.1002/anie.201905056

[UF₆ ]^2- : A Molecular Hexafluorido Actinide(IV) Complex with Compensating Spin and Orbital Magnetic Moments

Angew Chem Int Ed Engl. 2019 Oct 28;58(44):15650-15654. doi: 10.1002/anie.201905056. Epub 2019 Aug 7.

Authors

Kasper S Pedersen^{1

2}, Katie R Meihaus³, Andrei Rogalev⁴, Fabrice Wilhelm⁴, Daniel Aravena⁵, Martín Amoza⁶, Eliseo Ruiz⁶, Jeffrey R Long^{3

7

8}, Jesper Bendix⁹, Rodolphe Clérac¹

Affiliations

¹ Univ. Bordeaux, CNRS, Centre de Recherche Paul Pascal, UMR 5031, 33600, Pessac, France.
² Department of Chemistry, Technical University of Denmark, 2800 Kgs., Lyngby, Denmark.
³ Department of Chemistry, University of California, Berkeley, CA, 94720, USA.
⁴ ESRF-The European Synchrotron, 71, Avenue des Martyrs, 38000, Grenoble Cedex 9, France.
⁵ Departamento de Química de los Materiales, Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), Casilla 40, Correo 33, Santiago, Chile.
⁶ Departament de Química Inorgànica i Orgànica and Institut de Química Teòrica i Computacional, Universitat de Barcelona, Diagonal 645, 08028, Barcelona, Spain.
⁷ Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
⁸ Department of Chemical and Biomolecular Engineering, University of California Berkeley, Berkeley, CA, 94720, USA.
⁹ Department of Chemistry, University of Copenhagen, 2100, Copenhagen, Denmark.

PMID: 31290580
DOI: 10.1002/anie.201905056

Abstract

The first structurally characterized hexafluorido complex of a tetravalent actinide ion, the [UF₆ ]^2- anion, is reported in the (NEt₄ )₂ [UF₆ ]⋅2 H₂ O salt (1). The weak magnetic response of 1 results from both U^IV spin and orbital contributions, as established by combining X-ray magnetic circular dichroism (XMCD) spectroscopy and bulk magnetization measurements. The spin and orbital moments are virtually identical in magnitude, but opposite in sign, resulting in an almost perfect cancellation, which is corroborated by ab initio calculations. This work constitutes the first experimental demonstration of a seemingly non-magnetic molecular actinide complex carrying sizable spin and orbital magnetic moments.

Keywords: X-ray spectroscopy; electronic structure; fluorides; magnetic properties; uranium.

Abstract

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