title: Synthesis and characterization of a uranium(II) monoarene complex supported by δ backbonding.
abstract: The low-temperature (<-35 °C) reduction of the trivalent uranium monoarene complex [{((Ad,Me) ArO)3 mes}U] (1), with potassium spheres in the presence of a slight excess of 2.2.2-cryptand, affords the quantitative conversion of 1 into the uranium(II) monoarene complex [K(2.2.2-crypt)][(((Ad,Me) ArO)3 mes)U] (1-K). The molecular and electronic structure of 1-K was established experimentally by single-crystal X-ray diffraction, variable-temperature (1) H NMR and X-band EPR spectroscopy, solution-state and solid-state magnetism studies, and optical absorption spectroscopy. The electronic structure of the complex was further investigated by DFT calculations. The complete body of evidence confirms that 1-K is a uranium(II) monoarene complex with a 5f (4) electronic configuration supported by δ backbonding and that the nearly reversible, room-temperature reduction observed for 1 at -2.495 V vs. Fc/Fc(+) is principally metal-centered.
authors.affiliation: Inorganic Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander University Erlangen-Nürnberg, Egerlandstrasse 1, 91058 Erlangen (Germany).
authors.forename: Henry S
authors.initials: HS
authors.lastname: La Pierre
authors.forename: Andreas
authors.initials: A
authors.lastname: Scheurer
authors.forename: Frank W
authors.initials: FW
authors.lastname: Heinemann
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Hieringer
authors.forename: Karsten
authors.initials: K
authors.lastname: Meyer
mesh_terms: D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry*; D008958:Models, Molecular; D011188:Potassium / Q000737:chemistry; D011789:Quantum Theory; D014501:Uranium / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D014501:Uranium; D011188:Potassium
keywords: X-ray diffraction; arenes; electronic structure; magnetic properties; uranium