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Seed JA, Vondung L, Adams RW, Wooles AJ, Lu E, Liddle ST. Mesoionic Carbene Complexes of Uranium(IV) and Thorium(IV). Organometallics 2022; 41:1353-1363. [PMID: 36157256 PMCID: PMC9490841 DOI: 10.1021/acs.organomet.2c00120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Indexed: 11/30/2022]
Abstract
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We
report the synthesis and characterization of uranium(IV) and
thorium(IV) mesoionic carbene complexes [An{N(SiMe3)2}2(CH2SiMe2NSiMe3){MIC}] (An = U, 4U and Th, 4Th; MIC =
{CN(Me)C(Me)N(Me)CH}), which represent rare examples of actinide mesoionic
carbene linkages and the first example of a thorium mesoionic carbene
complex. Complexes 4U and 4Th were prepared
via a C–H activation intramolecular cyclometallation reaction
of actinide halides, with concomitant formal 1,4-proton migration
of an N-heterocyclic olefin (NHO). Quantum chemical
calculations suggest that the An–carbene bond comprises only
a σ-component, in contrast to the uranium(III) analogue [U{N(SiMe3)2}3(MIC)] (1) where computational
studies suggested that the 5f3 uranium(III) ion engages
in a weak one-electron π-backbond to the MIC. This highlights
the varying nature of actinide-MIC bonding as a function of actinide
oxidation state. In solution, 4Th exists in equilibrium
with the Th(IV) metallacycle [Th{N(SiMe3)2}2(CH2SiMe2NSiMe3)] (6Th) and free NHO (3). The thermodynamic parameters
of this equilibrium were probed using variable-temperature NMR spectroscopy
yielding an entropically favored but enthalpically endothermic process
with an overall reaction free energy of ΔG298.15K = 0.89 kcal mol–1. Energy decomposition
analysis (EDA-NOCV) of the actinide–carbon bonds in 4U and 4Th reveals that the former is enthalpically stronger
and more covalent than the latter, which accounts for the respective
stabilities of these two complexes.
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Affiliation(s)
- John A. Seed
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Lisa Vondung
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Ralph W. Adams
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Ashley J. Wooles
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Erli Lu
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Stephen T. Liddle
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
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DeJesus JF, Kerr RWF, Penchoff DA, Carroll XB, Peterson CC, Arnold PL, Jenkins DM. Actinide tetra-N-heterocyclic carbene 'sandwiches'. Chem Sci 2021; 12:7882-7887. [PMID: 34168841 PMCID: PMC8188502 DOI: 10.1039/d1sc01007g] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 04/15/2021] [Indexed: 11/21/2022] Open
Abstract
Highly-symmetrical, thorium and uranium octakis-carbene 'sandwich' complexes have been prepared by 'sandwiching' the An(iv) cations between two anionic macrocyclic tetra-NHC ligands, one with sixteen atoms and the other with eighteen atoms. The complexes were characterized by a range of experimental methods and DFT calculations. X-ray crystallography confirms the geometry at the metal centre can be set by the size of the macrocyclic ring, leading to either square prismatic or square anti-prismatic shapes; the geometry of the latter is retained in solution, which also undergoes reversible, electrochemical one-electron oxidation or reduction for the uranium variant. DFT calculations reveal a frontier orbital picture that is similar to thorocene and uranocene, in which the NHC ligands show almost exclusively σ-donation to the metal without π-backbonding.
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Affiliation(s)
- Joseph F DeJesus
- Department of Chemistry, The University of Tennessee Knoxville Tennessee 37996 USA
| | - Ryan W F Kerr
- School of Chemistry, University of Edinburgh West Mains Road Edinburgh EH9 3JJ UK
| | - Deborah A Penchoff
- Howard H. Baker Jr. Center for Public Policy, The University of Tennessee Knoxville Tennessee 37996 USA
| | - Xian B Carroll
- Department of Chemistry, The University of Tennessee Knoxville Tennessee 37996 USA
| | - Charles C Peterson
- Howard H. Baker Jr. Center for Public Policy, The University of Tennessee Knoxville Tennessee 37996 USA
- Research IT Services, University of North Texas Denton Texas 76201 USA
| | - Polly L Arnold
- School of Chemistry, University of Edinburgh West Mains Road Edinburgh EH9 3JJ UK
| | - David M Jenkins
- Department of Chemistry, The University of Tennessee Knoxville Tennessee 37996 USA
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Boreen MA, Gould CA, Booth CH, Hohloch S, Arnold J. Structure and magnetism of a tetrahedral uranium(iii) β-diketiminate complex. Dalton Trans 2020; 49:7938-7944. [PMID: 32495782 DOI: 10.1039/d0dt01599g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We describe the functionalisation of the previously reported uranium(iii) β-diketiminate complex (BDI)UI2(THF)2 (1) with one and two equivalents of a sterically demanding 2,6-diisopropylphenolate ligand (ODipp) leading to the formation of two heteroleptic complexes: [(BDI)UI(ODipp)]2 (2) and (BDI)U(ODipp)2 (3). The latter is a rare example of a tetrahedral uranium(iii) complex, and it shows single-molecule magnet behaviour.
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Affiliation(s)
- Michael A Boreen
- Department of Chemistry, University of California, Berkeley, California 94720, USA.
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4
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Edelmann FT, Farnaby JH, Jaroschik F, Wilson B. Lanthanides and actinides: Annual survey of their organometallic chemistry covering the year 2018. Coord Chem Rev 2019. [DOI: 10.1016/j.ccr.2019.07.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Baltrun M, Watt FA, Schoch R, Hohloch S. Dioxo-, Oxo-imido-, and Bis-imido-Molybdenum(VI) Complexes with a Bis-phenolate-NHC Ligand. Organometallics 2019. [DOI: 10.1021/acs.organomet.9b00472] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Marc Baltrun
- Paderborn University, Faculty of Science, Department of Chemistry, Warburger Straße 100, 33098 Paderborn, Germany
| | - Fabian A. Watt
- Paderborn University, Faculty of Science, Department of Chemistry, Warburger Straße 100, 33098 Paderborn, Germany
| | - Roland Schoch
- Paderborn University, Faculty of Science, Department of Chemistry, Warburger Straße 100, 33098 Paderborn, Germany
| | - Stephan Hohloch
- Paderborn University, Faculty of Science, Department of Chemistry, Warburger Straße 100, 33098 Paderborn, Germany
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6
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Hohloch S, Garner ME, Booth CH, Lukens WW, Gould CA, Lussier DJ, Maron L, Arnold J. Isolation of a TMTAA-Based Radical in Uranium bis-TMTAA Complexes. Angew Chem Int Ed Engl 2018; 57:16136-16140. [PMID: 30328669 DOI: 10.1002/anie.201810971] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Indexed: 01/02/2023]
Abstract
We report the synthesis, characterization, and electronic structure studies of a series of thorium(IV) and uranium(IV) bis-tetramethyltetraazaannulene complexes. These sandwich complexes show remarkable stability towards air and moisture, even at elevated temperatures. Electrochemical studies show the uranium complex to be stable in three different oxidation states; isolation of the oxidized species reveals a rare case of a non-innocent tetramethyltetraazaannulene (TMTAA) ligand.
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Affiliation(s)
- Stephan Hohloch
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, 94720, USA.,University of Paderborn, Warburger Straße 100, 33098, Paderborn, Germany
| | - Mary E Garner
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Corwin H Booth
- Chemical Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Wayne W Lukens
- Chemical Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Colin A Gould
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Daniel J Lussier
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, 94720, USA.,Chemical Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Laurent Maron
- LPCNO, Université de Toulouse, INSA Toulouse, 135 Avenue de Rangueil, 31077, Toulouse, France
| | - John Arnold
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, 94720, USA.,Chemical Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
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7
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Hohloch S, Garner ME, Booth CH, Lukens WW, Gould CA, Lussier DJ, Maron L, Arnold J. Isolation of a TMTAA‐Based Radical in Uranium bis‐TMTAA Complexes. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201810971] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Stephan Hohloch
- Department of Chemistry University of California, Berkeley Berkeley CA 94720 USA
- University of Paderborn Warburger Straße 100 33098 Paderborn Germany
| | - Mary E. Garner
- Department of Chemistry University of California, Berkeley Berkeley CA 94720 USA
| | - Corwin H. Booth
- Chemical Science Division Lawrence Berkeley National Laboratory Berkeley CA 94720 USA
| | - Wayne W. Lukens
- Chemical Science Division Lawrence Berkeley National Laboratory Berkeley CA 94720 USA
| | - Colin A. Gould
- Department of Chemistry University of California, Berkeley Berkeley CA 94720 USA
| | - Daniel J. Lussier
- Department of Chemistry University of California, Berkeley Berkeley CA 94720 USA
- Chemical Science Division Lawrence Berkeley National Laboratory Berkeley CA 94720 USA
| | - Laurent Maron
- LPCNO Université de Toulouse, INSA Toulouse 135 Avenue de Rangueil 31077 Toulouse France
| | - John Arnold
- Department of Chemistry University of California, Berkeley Berkeley CA 94720 USA
- Chemical Science Division Lawrence Berkeley National Laboratory Berkeley CA 94720 USA
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Ringgold M, Wu W, Stuber M, Kornienko AY, Emge TJ, Brennan JG. Monomeric thorium chalcogenolates with bipyridine and terpyridine ligands. Dalton Trans 2018; 47:14652-14661. [PMID: 30277236 DOI: 10.1039/c8dt02543f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Thorium chalcogenolates Th(ER)4 react with 2,2'-bipyridine (bipy) to form complexes with the stoichiometry (bipy)2Th(ER)4 (E = S, Se; R = Ph, C6F5). All four compounds have been isolated and characterized by spectroscopic methods and low-temperature single crystal X-ray diffraction. Two of the products, (bipy)2Th(SC6F5)4 and (bipy)2Th(SeC6F5)4, crystallize with lattice solvent, (bipy)2Th(SPh)4 crystallizes with no lattice solvent, and the selenolate (bipy)2Th(SePh)4 crystallizes in two phases, with and without lattice solvent. In all four compounds the available volume for coordination bounded by the two bipy ligands is large enough to allow significant conformational flexibility of thiolate or selenolate ligands. 77Se NMR confirms that the structures of the selenolate products are the same in pyridine solution and in the solid state. Attempts to prepare analogous derivatives with 2,2',6',2''-terpyridine (terpy) were successful only in the isolation of (terpy)(py)Th(SPh)4, the first terpy compound of thorium. These materials are thermochromic, with color attributed to ligand-to-ligand charge transfer excitations.
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Affiliation(s)
- Marissa Ringgold
- Department of Chemistry and Chemical Biology, Rutgers, the State University of New Jersey, 610 Taylor Road, Piscataway NJ 08854-8087, USA.
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9
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Garner ME, Parker BF, Hohloch S, Bergman RG, Arnold J. Thorium Metallacycle Facilitates Catalytic Alkyne Hydrophosphination. J Am Chem Soc 2017; 139:12935-12938. [PMID: 28892619 DOI: 10.1021/jacs.7b08323] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The bis(NHC)borate-supported thorium-bis(mesitylphosphido) complex (1) undergoes reversible intramolecular C-H bond activation enabling the catalytic hydrophosphination of unactivated internal alkynes. Catalytic and stoichiometric experiments support a mechanism involving reactive Th-NHC metallacycle intermediates (Int and 2).
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Affiliation(s)
- Mary E Garner
- Department of Chemistry, University of California, Berkeley , Berkeley, California 94720, United States
| | - Bernard F Parker
- Department of Chemistry, University of California, Berkeley , Berkeley, California 94720, United States
| | - Stephan Hohloch
- Department of Chemistry, University of California, Berkeley , Berkeley, California 94720, United States
| | - Robert G Bergman
- Department of Chemistry, University of California, Berkeley , Berkeley, California 94720, United States
| | - John Arnold
- Department of Chemistry, University of California, Berkeley , Berkeley, California 94720, United States
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