Molecular and Electronic Structures of Eight-Coordinate Uranium Bipyridine Complexes: A Rare Example of a Bipy(2-) Ligand Coordinated to a U4+ Ion

Journal article


Publication Details

Author(s): Rosenzweig M, Heinemann F, Maron L, Meyer K
Journal: Inorganic Chemistry
Publication year: 2017
Volume: 56
Journal issue: 5
Pages range: 2792-2800
ISSN: 1520-510X


Abstract

Reaction of trivalent [(((ArO)-Ar-Ad,tBu)(3)tacn)U] (1) with 2,2'-bipyridine (bipy) yields [(((ArO)-Ar-Ad,tBu)(3)tacn)U(bipy)] (2) and subsequent reduction of 2 with KC8 in the presence of Kryptofix222 furnishes [K(2.2.2-crypt)] [ (((ArO)-Ar-Ad,tBu)(3)tacn)U-(bipy)] (3). Alternatively, complex 3 can be synthesized from 1 by addition of [K(bipy)] in the presence of the cryptand. New complexes 2 and 3 are characterized by a variety of spectroscopic, electrochemical, and magnetochemical methods, single-crystal X-ray diffraction, computational methods, and CHN elemental analysis. Structural analyses reveal a bipyridine radical (bipy(center dot-)) ligand in 2 and a dianionic (bipy(2-)) species in 3. Complex 3 represents a rare example of an isolated and unambiguously characterized bipy(2-) ligand coordinated to a uranium ion. The electronic structure assignments are supported by UV/vis/NIR and EPR spectroscopy, as well as SQUID magnetometry. The results of CASSCF calculations indicate multiconfigurational ground states for complexes 2 and 3. The electronic ground state for 2 consists of an open-shell doublet U4+(bipy(center dot-)) state (91%) and a closed-shell doublet U5+(bipy(2-)) state (9%). The almost degenerate multiconfigurational ground state for 3 was found to be composed of an open shell singlet and pure triplet state 0.06 eV higher in energy, both resulting from the U4+(5f(2)) (bipy(2-)) configuration.


FAU Authors / FAU Editors

Heinemann, Frank Dr.
Lehrstuhl für Anorganische und Allgemeine Chemie
Meyer, Karsten Prof. Dr.
Lehrstuhl für Anorganische und Allgemeine Chemie
Rosenzweig, Michael
Lehrstuhl für Anorganische und Allgemeine Chemie


External institutions with authors

University of Toulouse


How to cite

APA:
Rosenzweig, M., Heinemann, F., Maron, L., & Meyer, K. (2017). Molecular and Electronic Structures of Eight-Coordinate Uranium Bipyridine Complexes: A Rare Example of a Bipy(2-) Ligand Coordinated to a U4+ Ion. Inorganic Chemistry, 56(5), 2792-2800. https://dx.doi.org/10.1021/acs.inorgchem.6b02954

MLA:
Rosenzweig, Michael, et al. "Molecular and Electronic Structures of Eight-Coordinate Uranium Bipyridine Complexes: A Rare Example of a Bipy(2-) Ligand Coordinated to a U4+ Ion." Inorganic Chemistry 56.5 (2017): 2792-2800.

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Last updated on 2018-17-07 at 13:08