1
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Brackbill IJ, Rajeshkumar T, Douair I, Maron L, Boreen MA, Bergman RG, Arnold J. Covalency-Driven Differences in the Hydrogenation Chemistry of Lanthanide- and Actinide-Based Frustrated Lewis Pairs. J Am Chem Soc 2024; 146:21932-21947. [PMID: 39051942 DOI: 10.1021/jacs.4c06777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
The electronic organization of Frustrated Lewis Pairs (FLPs) allows them to activate strong bonds in mechanisms that are usually free of redox events at the Lewis acidic site. The unique 6d/5f manifold of uranium could serve as an interesting FLP acceptor site, but to date FLP-like catalysis with actinide ions is unknown. In this paper, the catalytic, FLP-like hydrogenation reactivity of trivalent uranium complexes is explored in the presence of base-stabilized silylenes. Comparison to isoelectronic, isostructural lanthanide and thorium complexes lends insight into the electronic factors governing dihydrogen activation. Mechanistic studies of the uranium- and lanthanide-catalyzed hydrogenations are presented, including discussion of likely intermediates. Computational modeling of the f-element complexes, combined with experimental comparison to p-block Lewis acids, elucidates the relevance of steric hindrance to productive reactivity with dihydrogen. Consideration of the complete experimental and theoretical evidence provides a clear picture of the electronic and steric factors governing dihydrogen activation by these FLPs.
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Affiliation(s)
- I Joseph Brackbill
- Department of Chemistry, University of California, Berkeley, California 94720-1460, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720-1460, United States
| | - Thayalan Rajeshkumar
- LPCNO, Université de Toulouse, INSA Toulouse, 135 Avenue de Rangueil, 31077 Toulouse, France
| | - Iskander Douair
- LPCNO, Université de Toulouse, INSA Toulouse, 135 Avenue de Rangueil, 31077 Toulouse, France
| | - Laurent Maron
- LPCNO, Université de Toulouse, INSA Toulouse, 135 Avenue de Rangueil, 31077 Toulouse, France
| | - Michael A Boreen
- Department of Chemistry, University of California, Berkeley, California 94720-1460, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720-1460, United States
| | - Robert G Bergman
- Department of Chemistry, University of California, Berkeley, California 94720-1460, United States
| | - John Arnold
- Department of Chemistry, University of California, Berkeley, California 94720-1460, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720-1460, United States
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2
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Dutra FR, Vasiliu M, Gomez AN, Xia D, Dixon DA. Prediction of Redox Potentials for U, Np, Pu, and Am in Aqueous Solution. J Phys Chem A 2024; 128:5612-5626. [PMID: 38959054 DOI: 10.1021/acs.jpca.4c02902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
The redox properties of the actinides in aqueous solution are important for fuel production/reprocessing and understanding the environmental impact of nuclear waste. The redox potentials for U, Np, Pu, and Am in oxidation states from 0 up to VII (as appropriate) in aqueous solutions have been predicted at the density functional theory level with the B3LYP functional, Stuttgart small core pseudopotential basis sets for the actinides, and explicit (30H2O molecules)/implicit treatment of the aqueous solvent using the self-consistent reaction field COSMO and SMD approaches for the implicit solvation. The predictions of the structural parameters of clusters incorporating first and second solvation shells are consistent with the available experimental data. Our results are typically within 0.2 V of the available experimental data using two explicit solvation shells with an implicit solvent model. The use of the PW91 functional substantially improved the prediction of the Pu(VI/V) redox couple. The redox couples for An(VI/IV) and An(V/IV) which involve the addition of protons and removal of the actinyl oxygens led to slightly larger differences from an experiment. The An(IV/0) and An(III/0) couples were reliably predicted with our approach. Predictions of the unknown An(II/I) redox potentials were negative, consistent with expectations, and predictions for unknown An(VII/VI), An(III/II), and An(II/0) redox couples improve prior estimates.
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Affiliation(s)
- Felipe R Dutra
- Instituto de Química, Universidade Estadual de Campinas, Barão Geraldo, P.O. Box 6154, Campinas 13083-970, São Paulo, Brazil
- Department of Chemistry and Biochemistry, The University of Alabama, Shelby Hall, Tuscaloosa, Alabama 35487-0336, United States
| | - Monica Vasiliu
- Department of Chemistry and Biochemistry, The University of Alabama, Shelby Hall, Tuscaloosa, Alabama 35487-0336, United States
| | - Amber N Gomez
- Department of Chemistry and Biochemistry, The University of Alabama, Shelby Hall, Tuscaloosa, Alabama 35487-0336, United States
| | - Donna Xia
- Department of Chemistry and Biochemistry, The University of Alabama, Shelby Hall, Tuscaloosa, Alabama 35487-0336, United States
| | - David A Dixon
- Department of Chemistry and Biochemistry, The University of Alabama, Shelby Hall, Tuscaloosa, Alabama 35487-0336, United States
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3
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Samuvel Michael D, Schreckenbach G. Bis(acyl)phosphide Complexes of U(III)/U(IV): A Case of a Hidden Redox-Active Ligand. Inorg Chem 2024; 63:9711-9714. [PMID: 38749025 DOI: 10.1021/acs.inorgchem.4c00940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2024]
Abstract
The recently reported tris(bis(2,4,6-triisopropylbenzoyl)-phosphide)uranium (UIII(trippBAP)3, 2) complex (Inorg. Chem. 2022, 61 (32), 12508-12517) demonstrated a silent 31P NMR spectrum. This complex was described as a U(III) complex with an organic radical ligand fragment. Moreover, the EPR spectrum of 2 was indicative of an organic radical in the ligand framework complexed to uranium, in contrast to that of UIV(mesBAP)4, 1. Herein, with the help of relativistic density functional theory (DFT) calculations, the electronic structures of 1, 2, and U(mesBAP)3 (4) are examined in an effort to understand the unusual 31P NMR spectrum of 2. Results indicate the reduction of the carbonyl bonds and delocalization of the electrons over the ligands, indicative of U → L backbonding. Additionally, the reduced acyl carbons are found to exist as ketyl radicals [O═C• -] that are responsible for the silent 31P NMR spectra of 2. These findings demonstrate the redox noninnocent nature of BAP- in 2 and 4, causing uranium to exist in a formal oxidation state of +4.
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Affiliation(s)
- David Samuvel Michael
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada, R3T 2N2
| | - Georg Schreckenbach
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada, R3T 2N2
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4
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Modder DK, Scopelliti R, Mazzanti M. Accessing a Highly Reducing Uranium(III) Complex through Cyclometalation. Inorg Chem 2024; 63:9527-9538. [PMID: 38217471 DOI: 10.1021/acs.inorgchem.3c03668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2024]
Abstract
U(IV) cyclometalated complexes have shown rich reactivity, but their low oxidation state analogues still remain rare. Herein, we report the isolation of [K(2.2.2-cryptand)][UIII{N(SiMe3)2}2(κ2-C,N-CH2SiMe2NSiMe3)], 1, from the reduction of [UIII{N(SiMe)2}3] with KC8 and 2.2.2-cryptand at room temperature. Cyclic voltammetry studies demonstrate that 1 has a reduction potential similar to that of the previously reported [K(2.2.2-cryptand)][UII{N(SiMe)2}3] (Epc = -2.6 V versus Fc+/0 and Epc = -2.8 V versus Fc+/0, respectively). Complex 1, indeed, shows similar reducing abilities upon reactions with 4,4'-bipyridine, 2,2'-bipyridine, and 1-azidoadamantane. Interestingly, 1 was also found to be the first example of a mononuclear U(III) complex that is capable of reducing pyridine. In addition, it is shown that a wide variety of substrates can be inserted into the U-C bond, forming new U(III) metallacycles. These results highlight that cyclometalated U(III) complexes can serve as versatile precursors for a broad range of reactivity and for assembling a variety of novel chemical architectures.
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Affiliation(s)
- Dieuwertje K Modder
- Group of Coordination Chemistry, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Rosario Scopelliti
- Group of Coordination Chemistry, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Marinella Mazzanti
- Group of Coordination Chemistry, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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5
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Deng C, Liang J, Wang Y, Huang W. Reduction of Thorium Tris(amido)arene Complexes: Reversible Double and Single C-C Couplings. Inorg Chem 2024; 63:9676-9686. [PMID: 38696837 DOI: 10.1021/acs.inorgchem.4c00458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2024]
Abstract
The reduction chemistry of thorium complexes is less explored compared to that of their uranium counterparts. Here, we report the synthesis, characterization, and reduction chemistry of two thorium(IV) complexes, (AdTPBN3)ThCl (1) and (DtbpTPBN3)ThCl(THF) (4) [RTPBN3 = 1,3,5-[2-(RN)C6H4]3C6H3; R = 1-adamantyl (Ad) or 3,5-di-tert-butylphenyl (Dtbp); THF = tetrahydrofuran], supported by tripodal tris(amido)arene ligands with different N-substituents. Reduction of 1 with excessive potassium in n-pentane yielded a double C-C coupling product, [(AdTPBN3)ThK(Et2O)2]2 (3), featuring a unique tetraanionic tricyclic core. On the other hand, reduction of 4 with 1 equiv of KC8 in hexanes/1,2-dimethoxyethane (DME) afforded a single C-C coupling product, [(DtbpTPBN3)Th(DME)]2 (5), with a dianionic bis(cyclohexadienyl) core. The solid- and solution-state structures of dinuclear thorium(IV) complexes 3 and 5 were established by X-ray crystallography and NMR spectroscopy. In addition, reactivity studies show that 3 and 5 can behave as thorium(II) and thorium(III) synthons to reduce organic halides. For instance, 3 and 5 are able to reduce 4 and 2 equiv of benzyl chloride, respectively, to regenerate 1 and 4 with concomitant formation of dibenzyl. Reversible C-C couplings under redox conditions provide an alternative approach to exploiting the potential of thorium arene complexes in redox chemistry.
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Affiliation(s)
- Chong Deng
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
| | - Jiefeng Liang
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
| | - Yi Wang
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
| | - Wenliang Huang
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
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6
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Nguyen JQ, Wedal JC, Ziller JW, Furche F, Evans WJ. Investigating Steric and Electronic Effects in the Synthesis of Square Planar 6d 1 Th(III) Complexes. Inorg Chem 2024; 63:6217-6230. [PMID: 38502000 DOI: 10.1021/acs.inorgchem.3c04462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
The factors affecting the formation and crystal structures of unusual 6d1 Th(III) square planar aryloxide complexes, as exemplified by [Th(OArMe)4]1- (OArMe = OC6H2tBu2-2,6-Me-4), were explored by synthetic and reduction studies of a series of related Th(IV) tetrakis(aryloxide) complexes, Th(OArR)4 (OArR = OC6H2tBu2-2,6-R-4). Specifically, electronic, steric, and countercation effects were explored by varying the aryloxide ligand, the alkali metal reducing agent, and the alkali metal chelating agent. Salt metathesis reactions between ThBr4(DME)2 (DME = 1,2-dimethoxyethane) and 4 equiv of the appropriate potassium aryloxide salt were used to prepare a series of Th(IV) aryloxide complexes in high yields: Th(OArH)4 (OArH = OC6H3tBu2-2,6), Th(OArtBu)4 (OArtBu = OC6H2tBu3-2,4,6), Th(OArOMe)4 (OArOMe = OC6H2tBu2-2,6-OMe-4), and Th(OArPh)4 (OArPh = OC6H2tBu2-2,6-Ph-4). Th(OArH)4 can be reduced by KC8, Na, or Li in the absence or presence of 2.2.2-cryptand (crypt) or 18-crown-6 (crown) to form dark purple solutions that have EPR and UV-visible spectra similar to those of the square planar Th(III) complex, [Th(OArMe)4]1-. Hence, the para position of the aryloxide ligand does not have to be alkylated to obtain the Th(III) complexes. Furthermore, reduction of Th(OArOMe)4, Th(OArtBu)4, and Th(OArPh)4 with KC8 in THF generated purple solutions with EPR and UV-visible spectra that are similar to those of the previously reported Th(III) anion, [Th(OArMe)4]1-. Although many of these reduction reactions did not produce single crystals suitable for study by X-ray diffraction, reduction of Th(OArH)4, Th(OArtBu)4, and Th(OArOMe)4 with Li provided X-ray quality crystals whose structures had square planar coordination geometries. Reduction of Th(OArPh)4 with Li also gave a product with EPR and UV-visible spectra that matched those of [Th(OArMe)4]1-, but X-ray quality crystals of the reduction product were too unstable to provide data. Neither Th(Odipp)4(THF)2 (Odipp = OC6H3iPr2-2,6) nor Th(Odmp)4(THF)2 (Odmp = OC6H3Me2-2,6) could be reduced to Th(III) products under similar conditions. Reduction of U(OArH)3(THF) with KC8 in the presence of 2.2.2-cryptand (crypt) was examined for comparison and formed [K(crypt)][U(OArH)4], which has a tetrahedral arrangement of the aryloxide ligands. Moreover, no further reduction was observed when either [K(crypt)][U(OArH)4] or [K(crown)(THF)2][U(OArH)4] were treated with KC8 or Li.
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Affiliation(s)
- Joseph Q Nguyen
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, United States
| | - Justin C Wedal
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, United States
| | - Joseph W Ziller
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, United States
| | - Filipp Furche
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, United States
| | - William J Evans
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, United States
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7
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Wedal JC, Moore WNG, Lukens WW, Evans WJ. Perplexing EPR Signals from 5f 36d 1 U(II) Complexes. Inorg Chem 2024; 63:2945-2953. [PMID: 38279200 DOI: 10.1021/acs.inorgchem.3c03449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2024]
Abstract
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.
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Affiliation(s)
- Justin C Wedal
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
| | - William N G Moore
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
| | - Wayne W Lukens
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - William J Evans
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
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8
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Hsueh FC, Chen D, Rajeshkumar T, Scopelliti R, Maron L, Mazzanti M. Two-Electron Redox Reactivity of Thorium Supported by Redox-Active Tripodal Frameworks. Angew Chem Int Ed Engl 2024; 63:e202317346. [PMID: 38100190 DOI: 10.1002/anie.202317346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Indexed: 12/31/2023]
Abstract
The high stability of the + IVoxidation state limits thorium redox reactivity. Here we report the synthesis and the redox reactivity of two Th(IV) complexes supported by the arene-tethered tris(siloxide) tripodal ligands [(KOSiR2 Ar)3 -arene)]. The two-electron reduction of these Th(IV) complexes generates the doubly reduced [KTh((OSi(Ot Bu)2 Ar)3 -arene)(THF)2 ] (2OtBu ) and [K(2.2.2-cryptand)][Th((OSiPh2 Ar)3 -arene)(THF)2 ](2Ph -crypt) where the formal oxidation state of Th is +II. Structural and computational studies indicate that the reduction occurred at the arene anchor of the ligand. The robust tripodal frameworks store in the arene anchor two electrons that become available at the metal center for the two-electron reduction of a broad range of substrates (N2 O, COT, CHT, Ph2 N2 , Ph3 PS and O2 ) while retaining the ligand framework. This work shows that arene-tethered tris(siloxide) tripodal ligands allow implementation of two-electron redox chemistry at the thorium center while retaining the ligand framework unchanged.
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Affiliation(s)
- Fang-Che Hsueh
- Group of Coordination Chemistry, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Damien Chen
- Group of Coordination Chemistry, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Thayalan Rajeshkumar
- Laboratoire de Physique et Chimie des Nano-objets, Institut National des Sciences Appliquées, 31077, Toulouse Cedex 4, France
| | - Rosario Scopelliti
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Laurent Maron
- Laboratoire de Physique et Chimie des Nano-objets, Institut National des Sciences Appliquées, 31077, Toulouse Cedex 4, France
| | - Marinella Mazzanti
- Group of Coordination Chemistry, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
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9
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Otte KS, Niklas JE, Studvick CM, Boggiano AC, Bacsa J, Popov IA, La Pierre HS. Divergent Stabilities of Tetravalent Cerium, Uranium, and Neptunium Imidophosphorane Complexes. Angew Chem Int Ed Engl 2023; 62:e202306580. [PMID: 37327070 DOI: 10.1002/anie.202306580] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 06/15/2023] [Accepted: 06/16/2023] [Indexed: 06/18/2023]
Abstract
The study of the redox chemistry of mid-actinides (U-Pu) has historically relied on cerium as a model, due to the accessibility of trivalent and tetravalent oxidation states for these ions. Recently, dramatic shifts of lanthanide 4+/3+ non-aqueous redox couples have been established within a homoleptic imidophosphorane ligand framework. Herein we extend the chemistry of the imidophosphorane ligand (NPC=[N=Pt Bu(pyrr)2 ]- ; pyrr=pyrrolidinyl) to tetrahomoleptic NPC complexes of neptunium and cerium (1-M, 2-M, M=Np, Ce) and present comparative structural, electrochemical, and theoretical studies of these complexes. Large cathodic shifts in the M4+/3+ (M=Ce, U, Np) couples underpin the stabilization of higher metal oxidation states owing to the strongly donating nature of the NPC ligands, providing access to the U5+/4+ , U6+/5+ , and to an unprecedented, well-behaved Np5+/4+ redox couple. The differences in the chemical redox properties of the U vs. Ce and Np complexes are rationalized based on their redox potentials, degree of structural rearrangement upon reduction/oxidation, relative molecular orbital energies, and orbital composition analyses employing density functional theory.
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Affiliation(s)
- Kaitlyn S Otte
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332-0400, USA
| | - Julie E Niklas
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332-0400, USA
| | - Chad M Studvick
- Department of Chemistry, The University of Akron, Akron, OH, 44325-3601, USA
| | - Andrew C Boggiano
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332-0400, USA
| | - John Bacsa
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332-0400, USA
| | - Ivan A Popov
- Department of Chemistry, The University of Akron, Akron, OH, 44325-3601, USA
| | - Henry S La Pierre
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332-0400, USA
- Nuclear and Radiological Engineering Program, Georgia Institute of Technology, Atlanta, GA, 30332-0400, USA
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10
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Rupf SM, Sievers R, Riemann PS, Reimann M, Kaupp M, Fasting C, Malischewski M. Persilylation of ferrocene: the ultimate discipline in sterically overcrowded metal complexes. Dalton Trans 2023; 52:6870-6875. [PMID: 37157981 DOI: 10.1039/d3dt01133j] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We report the preparation and structural characterization of the first persilylated metallocene via the metalation of decabromoferrocene. Although Grignard conditions turned out to be insufficient due to the steric and electronic effects of silyl groups causing a decreased nucleophilicity of the metalated intermediates, stepwise lithium-halogen exchange yields complex mixtures of polysilylated compounds FeC10DMSnH10-n (n = 10, 9, 8) including the targeted decasilylated ferrocene. These mixtures were successfully separated allowing a systematic study of silylation effects on ferrocene by XRD, CV, NMR and UV/vis spectroscopy supported by DFT calculations. The findings were used to develop a high-yielding and simple preparation method to generate a tenfold substituted overcrowded ferrocene, FeC10DMS8Me2.
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Affiliation(s)
- Susanne M Rupf
- Freie Universität Berlin, Fabeckstr. 34-36, 14195 Berlin, Germany.
| | - Robin Sievers
- Freie Universität Berlin, Fabeckstr. 34-36, 14195 Berlin, Germany.
| | - Paulin S Riemann
- Freie Universität Berlin, Fabeckstr. 34-36, 14195 Berlin, Germany.
| | - Marc Reimann
- Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Martin Kaupp
- Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Carlo Fasting
- Freie Universität Berlin, Fabeckstr. 34-36, 14195 Berlin, Germany.
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11
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Riedhammer J, Halter DP, Meyer K. Nonaqueous Electrochemistry of Uranium Complexes: A Guide to Structure-Reactivity Tuning. Chem Rev 2023. [PMID: 37134149 DOI: 10.1021/acs.chemrev.2c00903] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Uranium complexes can be stabilized in a wide range of oxidation states, ranging from UII to UVI and a very recent example of a UI complex. This review provides a comprehensive summary of electrochemistry data reported on uranium complexes in nonaqueous electrolyte, to serve as a clear point of reference for newly synthesized compounds, and to evaluate how different ligand environments influence experimentally observed electrochemical redox potentials. Data for over 200 uranium compounds are reported, together with a detailed discussion of trends observed across larger series of complexes in response to ligand field variations. In analogy to the traditional Lever parameter, we utilized the data to derive a new uranium-specific set of ligand field parameters UEL(L) that more accurately represent metal-ligand bonding situations than previously existing transition metal derived parameters. Exemplarily, we demonstrate UEL(L) parameters to be useful for the prediction of structure-reactivity correlations in order to activate specific substrate targets.
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Affiliation(s)
- Judith Riedhammer
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstrasse 1, 91058 Erlangen, Germany
| | - Dominik P Halter
- Department of Chemistry, Chair of Inorganic and Metal-Organic Chemistry, Technical University of Munich (TUM), TUM School of Natural Sciences, Lichtenbergstrasse 4, 85748 Garching, Germany
| | - Karsten Meyer
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstrasse 1, 91058 Erlangen, Germany
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12
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Hsueh FC, Rajeshkumar T, Kooij B, Scopelliti R, Severin K, Maron L, Zivkovic I, Mazzanti M. Bonding and Reactivity in Terminal versus Bridging Arenide Complexes of Thorium Acting as Th II Synthons. Angew Chem Int Ed Engl 2023; 62:e202215846. [PMID: 36576035 DOI: 10.1002/anie.202215846] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/23/2022] [Accepted: 12/27/2022] [Indexed: 12/29/2022]
Abstract
Thorium redox chemistry is extremely scarce due to the high stability of ThIV . Here we report two unique examples of thorium arenide complexes prepared by reduction of a ThIV -siloxide complex in presence of naphthalene, the mononuclear arenide complex [K(OSi(Ot Bu)3 )3 Th(η6 -C10 H8 )] (1) and the inverse-sandwich complex [K(OSi(Ot Bu)3 )3 Th]2 (μ-η6 ,η6 -C10 H8 )] (2). The electrons stored in these complexes allow the reduction of a broad range of substrates (N2 O, AdN3 , CO2 , HBBN). Higher reactivity was found for the complex 1 which reacts with the diazoolefin IDipp=CN2 to yield the unexpected ThIV amidoalkynyl complex 5 via a terminal N-heterocyclic vinylidene intermediate. This work showed that arenides can act as convenient redox-active ligands for implementing thorium-ligand cooperative multielectron transfer and that the reactivity can be tuned by the arenide binding mode.
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Affiliation(s)
- Fang-Che Hsueh
- Group of Coordination Chemistry, Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Thayalan Rajeshkumar
- Laboratoire de Physique et Chimie des Nano-objets, Institut National des Sciences Appliquées, 31077, Toulouse Cedex 4, France
| | - Bastiaan Kooij
- Laboratory of Supramolecular Chemistry, Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Rosario Scopelliti
- Group of Coordination Chemistry, Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Kay Severin
- Laboratory of Supramolecular Chemistry, Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Laurent Maron
- Laboratoire de Physique et Chimie des Nano-objets, Institut National des Sciences Appliquées, 31077, Toulouse Cedex 4, France
| | - Ivica Zivkovic
- Laboratory for Quantum Magnetism, Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Marinella Mazzanti
- Group of Coordination Chemistry, Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
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13
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Wedal JC, Murillo J, Ziller JW, Scott BL, Gaunt AJ, Evans WJ. Synthesis of Trimethyltriazacyclohexane (Me 3tach) Sandwich Complexes of Uranium, Neptunium, and Plutonium Triiodides: (Me 3tach) 2AnI 3. Inorg Chem 2022; 62:5897-5905. [PMID: 36576312 DOI: 10.1021/acs.inorgchem.2c03306] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
1,3,5-Trimethyl-1,3,5-triazacyclohexane (Me3tach) readily complexes uranium triiodide to form (Me3tach)2UI3. The complex is soluble in THF and arenes and can function as a source of UI3 to form organometallic U(III) complexes. When dissolved in pyridine (py), (Me3tach)2UI3 forms (Me3tach)UI3(py)2. A related complex with the larger 1,4,7-trimethyl-1,4,7-triazacyclononane (Me3tacn) ligand, namely (Me3tacn)UI3(THF), was synthesized for comparison. Since X-ray quality crystals of (Me3tach)2UI3 can be synthesized in high yield even with small-scale reactions, the system is ideal for extension to transuranium elements. Accordingly, the neptunium and plutonium complexes (Me3tach)2NpI3 and (Me3tach)2PuI3 were synthesized in an analogous manner from NpI3(THF)4 and PuI3(THF)4, respectively.
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Affiliation(s)
- Justin C Wedal
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
| | - Jesse Murillo
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Joseph W Ziller
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
| | - Brian L Scott
- Materials Physics & Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Andrew J Gaunt
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - William J Evans
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
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14
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Bansal D, Kaden P, Patzschke M, März J, Schmidt M. Comparative Analysis of Mononuclear 1:1 and 2:1 Tetravalent Actinide (U, Th, Np) Complexes: Crystal Structure, Spectroscopy, and Electrochemistry. Inorg Chem 2022; 61:10509-10520. [PMID: 35736135 DOI: 10.1021/acs.inorgchem.2c01405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Six mononuclear tetravalent actinide complexes (1-6) have been synthesized using a new Schiff base ligand 2-methoxy-6-(((2-methyl-1-(pyridin-2-yl)propyl)imino)methyl)phenol (HLpr). The HLpr is treated with tetravalent actinide elements in varied stoichiometries to afford mononuclear 1:1 complexes [MCl3-Lpr·nTHF] (1-3) and 2:1 complexes [MCl2-L2pr] (4-6) (M = Th4+ (1 and 4), U4+ (2 and 5), and Np4+ (3 and 6)). All complexes are characterized using different analytical techniques such as IR, NMR, and absorption spectroscopy as well as crystallography. UV-vis spectroscopy revealed more red-shifted absorption spectra for 2:1 complexes as compared to 1:1 complexes. 1H NMR of Th(IV) complexes exhibit diamagnetic spectra, whereas U(IV) and Np(IV) complexes revealed paramagnetically shifted 1H NMR. Interestingly, NMR signals are paramagnetically shifted between -70 and 40 ppm in 2 and 3 but are confined within -35 to 25 ppm in 2:1 complexes 5 and 6. Single-crystal structures for 1:1 complexes revealed an eight-coordinated Th(IV) complex (1) and seven-coordinated U(IV) (2) and Np(IV) (3) complexes. However, all 2:1 complexes 4-6 were isolated as eight-coordinated isostructural molecules. The geometry around the Th4+ center in 1 is found to be trigonal dodecahedral and capped trigonal prismatic around U(IV) and Np(IV) centers in 2 and 3, respectively. However, An4+ centers in 2:1 complexes are present in dodecahedral geometry. Importantly, 2:1 complexes exhibit increased bond distances in comparison to their 1:1 counterparts as well as interesting bond modulation with respect to ionic radii of An(IV) centers. Cyclic voltammetry displays an increased oxidation potential of the ligand by 300-500 mV, after coordination with An4+. CV studies indicate Th(IV)/Th(II) reduction beyond -2.3 V, whereas attempts were made to identify redox potentials for U(IV) and Np(IV) centers. Spectroscopic binding studies reveal that complex stability in 1:1 stoichiometry follows the order Th4+ ≈ U4+ > Np4+.
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Affiliation(s)
- Deepak Bansal
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Peter Kaden
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Michael Patzschke
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Juliane März
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Moritz Schmidt
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden, Germany
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15
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Wedal JC, Ziller JW, Furche F, Evans WJ. Synthesis and Reduction of Heteroleptic Bis(cyclopentadienyl) Uranium(III) Complexes. Inorg Chem 2022; 61:7365-7376. [PMID: 35504019 DOI: 10.1021/acs.inorgchem.2c00322] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Heteroleptic U(III) complexes supported by bis(cyclopentadienyl) frameworks have been synthesized to examine their suitability as precursors to U(II) complexes. The newly synthesized (C5Me5)2U(OC6H2tBu2-2,6-Me-4), (C5Me5)2U(OC6H2Ad2-2,6-tBu-4) (Ad = 1-adamantyl), (C5Me5)2U(C5H5), and (C5Me5)2U(C5Me4H) are compared with (C5Me5)2U[N(SiMe3)2], (C5Me5)2U[CH(SiMe3)2], and (C5Me5)U[N(SiMe3)2]2. An improved synthesis of (C5Me5)2U(μ-Ph)2BPh2 was developed, which was used to synthesize (C5Me5)2U(C5Me4H). Since the X-ray crystal structure of (C5Me5)2U(OC6H2tBu2-2,6-Me-4) contained two very different molecules in the asymmetric unit with 115.7(5)° and 166.0(5)° U-O-Cipso angles, the (C5Me4H)2U(OC6H2tBu2-2,6-Me-4) and (C5Me5)2Ce(OC6H2tBu2-2,6-Me-4) analogues were synthesized and characterized by X-ray diffraction for comparison. Electrochemical studies in THF with a 100 mM [nBu4N][BPh4] supporting electrolyte showed U(IV)/U(III) and U(III)/U(II) redox couples for all the heteroleptic complexes except (C5Me5)2U(C5H5). Chemical reduction of all heteroleptic compounds formed dark blue solutions characteristic of U(II) when reacted with KC8 at -78 °C, but none formed isolable U(II) complexes. The targeted U(II) complexes, [(C5Me5)2U(OC6H2tBu2-2,6-Me-4)]1-, {(C5Me5)2U[CH(SiMe3)2]}1-, [(C5Me5)2U(C5H5)]1-, and [(C5Me5)2U(C5Me4H)]1-, were analyzed by density functional theory, and a 5f36d1 electron configuration was found to be the ground state in each case.
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Affiliation(s)
- Justin C Wedal
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
| | - Joseph W Ziller
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
| | - Filipp Furche
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
| | - William J Evans
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
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16
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Wedal JC, Cajiao N, Neidig ML, Evans WJ. Anion-induced disproportionation of Th(III) complexes to form Th(II) and Th(IV) products. Chem Commun (Camb) 2022; 58:5289-5291. [PMID: 35403646 DOI: 10.1039/d2cc01272c] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new synthesis of Th(II) complexes has been identified involving addition of simple MX salts (M = Li, Na, K; X = H, Cl, Me, N3) to Cp''3ThIII [Cp'' = [C5H3(SiMe3)2] in the presence of 18-crown-6 or 2.2.2-cryptand, forming [M(chelate)][Cp''3ThII] and Cp''3ThIVX. Cptet3ThIII (Cptet = C5Me4H) reacts with KH to form Cptet3ThIVH and the C-H bond activation product, [K(crypt)]{[Cptet2ThIVH[η1:η5-C5Me3H(CH2)]}.
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Affiliation(s)
- Justin C Wedal
- Department of Chemistry, University of California, Irvine, California 92697-2025, USA.
| | - Nathalia Cajiao
- Department of Chemistry, University of Rochester, Rochester, New York 14627, USA.
| | - Michael L Neidig
- Department of Chemistry, University of Rochester, Rochester, New York 14627, USA.
| | - William J Evans
- Department of Chemistry, University of California, Irvine, California 92697-2025, USA.
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17
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Köhler L, Patzschke M, Bauters S, Vitova T, Butorin SM, Kvashnina KO, Schmidt M, Stumpf T, März J. Insights into the Electronic Structure of a U(IV) Amido and U(V) Imido Complex. Chemistry 2022; 28:e202200119. [PMID: 35179271 PMCID: PMC9310906 DOI: 10.1002/chem.202200119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Indexed: 01/02/2023]
Abstract
Reaction of the N‐heterocylic carbene ligand iPrIm (L1) and lithium bis(trimethylsilyl)amide (TMSA) as a base with UCl4 resulted in U(IV) and U(V) complexes. Uranium's +V oxidation state in (HL1)2[U(V)(TMSI)Cl5] (TMSI=trimethylsilylimido) (2) was confirmed by HERFD‐XANES measurements. Solid state characterization by SC‐XRD and geometry optimisation of [U(IV)(L1)2(TMSA)Cl3] (1) indicated a silylamido ligand mediated inverse trans influence (ITI). The ITI was examined regarding different metal oxidation states and was compared to transition metal analogues by theoretical calculations.
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Affiliation(s)
- Luisa Köhler
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology, Bautzner Landstraße 400, 01328, Dresden, Germany
| | - Michael Patzschke
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology, Bautzner Landstraße 400, 01328, Dresden, Germany
| | - Stephen Bauters
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology, Bautzner Landstraße 400, 01328, Dresden, Germany.,The Rossendorf Beamline at ESRF at the European Synchrotron, CS40220, 38043, Grenoble Cedex 9, France
| | - Tonya Vitova
- Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal (INE), P.O. Box 3640, 76021, Karlsruhe, Germany
| | - Sergei M Butorin
- Condensed Matter Physics of Energy Materials, X-ray Photon Science, Department of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-751 20, Uppsala, Sweden
| | - Kristina O Kvashnina
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology, Bautzner Landstraße 400, 01328, Dresden, Germany.,The Rossendorf Beamline at ESRF at the European Synchrotron, CS40220, 38043, Grenoble Cedex 9, France
| | - Moritz Schmidt
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology, Bautzner Landstraße 400, 01328, Dresden, Germany
| | - Thorsten Stumpf
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology, Bautzner Landstraße 400, 01328, Dresden, Germany
| | - Juliane März
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology, Bautzner Landstraße 400, 01328, Dresden, Germany
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18
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Lam FYT, Wells JAL, Ochiai T, Halliday CJV, McCabe KN, Maron L, Arnold PL. A Combined Experimental and Theoretical Investigation of Arene-Supported Actinide and Ytterbium Tetraphenolate Complexes. Inorg Chem 2022; 61:4581-4591. [PMID: 35244386 DOI: 10.1021/acs.inorgchem.1c03365] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Modular tetraphenolate ligands tethered with a protective arene platform (para-phenyl or para-terphenyl) are used to support mononuclear An(IV) (An = Th, U) complexes with an exceptionally large and open axial coordination site at the metal. The base-free complexes and a series of neutral donor adducts were synthesized and characterized by spectroscopies and single-crystal X-ray diffraction. Anionic Th(IV) -ate complexes with an additional axial aryloxide ligand were also synthesized and characterized. The para-phenyl-tethered mononuclear complexes exhibit rare An(IV)-arene interactions, and the An(IV)-arene distance broadly increases with axial donor strength. The para-terphenyl-tethered complexes have almost no interaction with the arene base, isolating the central metal cation. Computational analysis of the mononuclear complexes and their reduced analogues, and Yb(III) congeners, as well as the effect of additional donor ligand binding, seek to elucidate the electronic structure of the metal-arene interactions and establish whether they, or their reduced or oxidized counterparts, could function as molecular qubits.
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Affiliation(s)
- Francis Y T Lam
- Department of Chemistry, Chemical Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, Berkeley, California 94720, United States.,EaStCHEM School of Chemistry, The University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, United Kingdom
| | - Jordann A L Wells
- EaStCHEM School of Chemistry, The University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, United Kingdom
| | - Tatsumi Ochiai
- Department of Chemistry, Chemical Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, Berkeley, California 94720, United States.,EaStCHEM School of Chemistry, The University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, United Kingdom
| | - Connor J V Halliday
- EaStCHEM School of Chemistry, The University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, United Kingdom
| | - Karl N McCabe
- Université de Toulouse and CNRS, INSA, UPS, CNRS, UMR 5215, LPCNO, 135 Avenue de Rangueil, F-31077 Toulouse, France
| | - Laurent Maron
- Université de Toulouse and CNRS, INSA, UPS, CNRS, UMR 5215, LPCNO, 135 Avenue de Rangueil, F-31077 Toulouse, France
| | - Polly L Arnold
- Department of Chemistry, Chemical Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, Berkeley, California 94720, United States.,EaStCHEM School of Chemistry, The University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, United Kingdom
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19
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Jori N, Rajeshkumar T, Scopelliti R, Z̆ivković I, Sienkiewicz A, Maron L, Mazzanti M. Cation assisted binding and cleavage of dinitrogen by uranium complexes. Chem Sci 2022; 13:9232-9242. [PMID: 36093011 PMCID: PMC9384805 DOI: 10.1039/d2sc02530b] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 07/12/2022] [Indexed: 11/21/2022] Open
Abstract
N2 binding affinity decreases markedly in a series of isostructural U(iii)–alkali ions complexes with increasing cation size. N2 binding is undetectable in the Cs analogue, but the first example of cesium-assisted N2 cleavage to bis-nitride was observed at ambient condition.
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Affiliation(s)
- Nadir Jori
- Insititut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Thayalan Rajeshkumar
- Laboratoire de Physique et Chimie des Nano-objets, Institut National des Sciences Appliquées, Cedex 4, 31077 Toulouse, France
| | - Rosario Scopelliti
- Insititut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Ivica Z̆ivković
- Laboratory for Quantum Magnetism, Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, 1015, Switzerland
| | - Andrzej Sienkiewicz
- Laboratory for Quantum Magnetism, Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
- ADSresonances Sàrl, Route de Genève 60B, 1028 Préverenges, Switzerland
| | - Laurent Maron
- Laboratoire de Physique et Chimie des Nano-objets, Institut National des Sciences Appliquées, Cedex 4, 31077 Toulouse, France
| | - Marinella Mazzanti
- Insititut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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20
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Trinh MT, Wedal JC, Evans WJ. Evaluating electrochemical accessibility of 4f n5d 1 and 4f n+1 Ln(II) ions in (C 5H 4SiMe 3) 3Ln and (C 5Me 4H) 3Ln complexes. Dalton Trans 2021; 50:14384-14389. [PMID: 34569559 DOI: 10.1039/d1dt02427b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reduction potentials (reported vs. Fc+/Fc) for a series of Cp'3Ln complexes (Cp' = C5H4SiMe3, Ln = lanthanide) were determined via electrochemistry in THF with [nBu4N][BPh4] as the supporting electrolyte. The Ln(III)/Ln(II) reduction potentials for Ln = Eu, Yb, Sm, and Tm (-1.07 to -2.83 V) follow the expected trend for stability of 4f7, 4f14, 4f6, and 4f13 Ln(II) ions, respectively. The reduction potentials for Ln = Pr, Nd, Gd, Tb, Dy, Ho, Er, and Lu, that form 4fn5d1 Ln(II) ions (n = 2-14), fall in a narrow range of -2.95 V to -3.14 V. Only cathodic events were observed for La and Ce at -3.36 V and -3.43 V, respectively. The reduction potentials of the Ln(II) compounds [K(2.2.2-cryptand)][Cp'3Ln] (Ln = Pr, Sm, Eu) match those of the Cp'3Ln complexes. The reduction potentials of nine (C5Me4H)3Ln complexes were also studied and found to be 0.05-0.24 V more negative than those of the Cp'3Ln compounds.
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Affiliation(s)
- Michael T Trinh
- Department of Chemistry, University of California, Irvine, California 92697-2025, USA.
| | - Justin C Wedal
- Department of Chemistry, University of California, Irvine, California 92697-2025, USA.
| | - William J Evans
- Department of Chemistry, University of California, Irvine, California 92697-2025, USA.
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21
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Moore WNG, Ziller JW, Evans WJ. Optimizing Alkali Metal (M) and Chelate (L) Combinations for the Synthesis and Stability of [M(L)][(C 5H 4SiMe 3) 3Y] Yttrium(II) Complexes. Organometallics 2021. [DOI: 10.1021/acs.organomet.1c00379] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- William N. G. Moore
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, United States
| | - Joseph W. Ziller
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, United States
| | - William J. Evans
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, United States
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22
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Rupasinghe DMRYP, Gupta H, Baxter MR, Higgins RF, Zeller M, Schelter EJ, Bart SC. Elucidation of Thorium Redox-Active Ligand Complexes: Evidence for a Thorium-Tri(radical) Species. Inorg Chem 2021; 60:14302-14309. [PMID: 34498847 DOI: 10.1021/acs.inorgchem.1c01859] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A series of thorium(IV) complexes featuring the redox-active 4,6-di-tert-butyl-N-(2,6-di-isopropylphenyl)-o-iminobenzoquinone (dippiq) ligand family have been synthesized and characterized. The neutral iminoquinone ligand was used to generate Th(dippiq)Cl4(dme)2 (1-iq) and Th(dippiq)2Cl4 (2-iq), both of which show dative bonds between the thorium(IV) ion and the ligands. One electron reduction of the ligand forms the unique tris(iminosemiquinone) complex, Th(dippisq)3Cl (3-isq), which features a radical in each ligand. Further reduction furnishes the amidophenolate species, Th(dippap)3]K2(THF)2 (4-ap), which has the ligands in their dianionic form. Attempts to sequester the potassium ions with cryptand resulted in the [Th(dippap)3K][K(crypt)] (4-ap mono crypt) and [Th(dippap)3][K(crypt)]2 (4-ap crypt) species. A bis(amidophenolate) complex was accessed by incorporating bulky triphenylphosphine oxide (OPPh3) ligands to generate Th(dippap)2(OPPh)3 (5-ap). Spectroscopic and structural characterization of each derivative established the +4 oxidation state for thorium with redox chemistry occurring at the ligands rather than the thorium ion. The reported 3-isq complex is unprecedented as it is the first tri(radical) thorium complex with the highest reported magnetic moment for a thorium species as characterized by SQUID magnetometry.
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Affiliation(s)
- D M Ramitha Y P Rupasinghe
- H. C. Brown Laboratory, Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Himanshu Gupta
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Makayla R Baxter
- H. C. Brown Laboratory, Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Robert F Higgins
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Matthias Zeller
- H. C. Brown Laboratory, Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Eric J Schelter
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Suzanne C Bart
- H. C. Brown Laboratory, Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
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