1
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Liddle ST. Progress in Nonaqueous Molecular Uranium Chemistry: Where to Next? Inorg Chem 2024; 63:9366-9384. [PMID: 38739898 PMCID: PMC11134516 DOI: 10.1021/acs.inorgchem.3c04533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 04/24/2024] [Accepted: 04/25/2024] [Indexed: 05/16/2024]
Abstract
There is long-standing interest in nonaqueous uranium chemistry because of fundamental questions about uranium's variable chemical bonding and the similarities of this pseudo-Group 6 element to its congener d-block elements molybdenum and tungsten. To provide historical context, with reference to a conference presentation slide presented around 1988 that advanced a defining collection of top targets, and the challenge, for synthetic actinide chemistry to realize in isolable complexes under normal experimental conditions, this Viewpoint surveys progress against those targets, including (i) CO and related π-acid ligand complexes, (ii) alkylidenes, carbynes, and carbidos, (iii) imidos and terminal nitrides, (iv) homoleptic polyalkyls, -alkoxides, and -aryloxides, (v) uranium-uranium bonds, and (vi) examples of topics that can be regarded as branching out in parallel from the leading targets. Having summarized advances from the past four decades, opportunities to build on that progress, and hence possible future directions for the field, are highlighted. The wealth and diversity of uranium chemistry that is described emphasizes the importance of ligand-metal complementarity in developing exciting new chemistry that builds our knowledge and understanding of elements in a relativistic regime.
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Affiliation(s)
- Stephen T. Liddle
- Department of Chemistry and Centre
for Radiochemistry Research, The University
of Manchester, Oxford Road, Manchester M13 9PL, U.K.
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2
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Lee VY, Gapurenko OA. Pyramidanes: newcomers to the anti-van't Hoff-Le Bel family. Chem Commun (Camb) 2023; 59:10067-10086. [PMID: 37551825 DOI: 10.1039/d3cc02757k] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/09/2023]
Abstract
In this feature article, an overview of the chemistry of pyramidanes, as a novel class of main group element clusters, is given. A general introduction sets the scene, briefly presenting the non-classical pyramidal geometry of tetracoordinate carbon, as opposed to the classical tetrahedral configuration. Pyramidanes, as the simplest organic compounds possessing a pyramidal carbon atom, are then discussed from both computational and experimental viewpoints, to show the theoretical predictions on the stability and thus the feasibility of pyramidanes has finally culminated in the isolation of the first stable representatives of the pyramidane family featuring heavy main group elements at the apex of the square pyramid. Synthetic strategies towards pyramidanes, as well as their peculiar structural features, non-classical bonding situations, and specific reactivity, are presented and discussed in this review.
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Affiliation(s)
- Vladimir Ya Lee
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8571, Ibaraki, Japan.
| | - Olga A Gapurenko
- Institute of Physical and Organic Chemistry, Southern Federal University, Rostov on Don 344090, Russian Federation.
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3
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Price AN, Gupta AK, de Jong WA, Arnold PL. Tris(carbene)borates; alternatives to cyclopentadienyls in organolanthanide chemistry. Dalton Trans 2023; 52:5433-5437. [PMID: 37070223 PMCID: PMC10222825 DOI: 10.1039/d3dt00718a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
Abstract
The chemistry of the tris-carbene anion phenyltris(3-alkyl-imidazoline-2-yliden-1-yl)borate, [C3Me]- ligand, is initiated for f-block metal cations. Neutral, molecular complexes of the form Ln(C3)2I are formed for cerium(III), while a separated ion pair [Ln(C3)2]I forms for ytterbium(III). DFT/QTAIM computational analyses of the complexes and related tridentate tris(pyrazolyl)borate (Tp) - supported analogs demonstrates the anticipated strength of the σ donation and confirms greater covalency in the metal-carbon bonds of the [C3Me]- complexes in comparison with those in the TpMe,Me complexes. The DFT calculations demonstrate the crucial role of THF solvent in accurately reproducing the contrasting molecular and ion-pair geometries observed experimentally for the Ce and Yb complexes.
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Affiliation(s)
- Amy N Price
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley, CA 94720, USA.
- Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720-1460, USA
| | - Ankur K Gupta
- Applied Mathematics and Computational Science Division, Lawrence Berkeley National Laboratory Berkeley, CA 94720, USA
| | - Wibe A de Jong
- Applied Mathematics and Computational Science Division, Lawrence Berkeley National Laboratory Berkeley, CA 94720, USA
| | - Polly L Arnold
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley, CA 94720, USA.
- Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720-1460, USA
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4
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Tsoureas N, Rajeshkumar T, Townrow OPE, Maron L, Layfield RA. Thorium- and Uranium-Mediated C-H Activation of a Silyl-Substituted Cyclobutadienyl Ligand. Inorg Chem 2022; 61:20629-20635. [PMID: 36484644 PMCID: PMC9768750 DOI: 10.1021/acs.inorgchem.2c03534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cyclobutadienyl complexes of the f-elements are a relatively new yet poorly understood class of sandwich and half-sandwich organometallic compounds. We now describe cyclobutadienyl transfer reactions of the magnesium reagent [(η4-Cb'''')Mg(THF)3] (1), where Cb'''' is tetrakis(trimethylsilyl)cyclobutadienyl, toward thorium(IV) and uranium(IV) tetrachlorides. The 1:1 stoichiometric reactions between 1 and AnCl4 proceed with intact transfer of Cb'''' to give the half-sandwich complexes [(η4-Cb'''')AnCl(μ-Cl)3Mg(THF)3] (An = Th, 2; An = U, 3). Using a 2:1 reaction stoichiometry produces [Mg2Cl3(THF)6][(η4-Cb'''')An(η3-C4H(SiMe3)3-κ-(CH2SiMe2)(Cl)] (An = Th, [Mg2Cl3(THF)6][4]; An = U [Mg2Cl3(THF)6][5]), in which one Cb'''' ligand has undergone cyclometalation of a trimethylsilyl group, resulting in the formation of an An-C σ-bond, protonation of the four-membered ring, and an η3-allylic interaction with the actinide. Complex solution-phase dynamics are observed with multinuclear nuclear magnetic resonance spectroscopy for both sandwich complexes. A computational analysis of the reaction mechanism leading to the formation of 4 and 5 indicates that the cyclobutadienyl ligands undergo C-H activation across the actinide center.
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Affiliation(s)
- Nikolaos Tsoureas
- Department
of Chemistry, School of Life Sciences, University
of Sussex, Brighton BN1 9QJ, U.K.
| | - Thayalan Rajeshkumar
- Laboratoire
de Physique et Chimie des Nano-Objets, Institut
National des Sciences Appliquées, Toulouse Cedex 4 31077, France
| | - Oliver P. E. Townrow
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K.
| | - Laurent Maron
- Laboratoire
de Physique et Chimie des Nano-Objets, Institut
National des Sciences Appliquées, Toulouse Cedex 4 31077, France,
| | - Richard A. Layfield
- Department
of Chemistry, School of Life Sciences, University
of Sussex, Brighton BN1 9QJ, U.K.,
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5
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Rong Wong Z, Schramm TK, Loipersberger M, Head-Gordon M, Toste FD. Revisiting the Bonding Model for Gold(I) Species: The Importance of Pauli Repulsion Revealed in a Gold(I)-Cyclobutadiene Complex. Angew Chem Int Ed Engl 2022; 61:e202202019. [PMID: 35261142 PMCID: PMC9173747 DOI: 10.1002/anie.202202019] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Indexed: 11/12/2022]
Abstract
Understanding the bonding of gold(I) species has been central to the development of gold(I) catalysis. Herein, we present the synthesis and characterization of the first gold(I)-cyclobutadiene complex, accompanied with bonding analysis by state-of-the-art energy decomposition analysis methods. Analysis of possible coordination modes for the new species not only confirms established characteristics of gold(I) bonding, but also suggests that Pauli repulsion is a key yet hitherto overlooked element. Additionally, we obtain a new perspective on gold(I)-bonding by comparison of the gold(I)-cyclobutadiene to congeners stabilized by p-, d-, and f-block metals. Consequently, we refine the gold(I) bonding model, with a delicate interplay of Pauli repulsion and charge transfer as the key driving force for various coordination motifs. Pauli repulsion is similarly determined as a significant interaction in AuI -alkyne species, corroborating this revised understanding of AuI bonding.
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Affiliation(s)
- Zeng Rong Wong
- Department of Chemistry, University of California, Berkeley 420 Latimer Hall, Berkeley, CA 94720 (USA)
| | - Tim K. Schramm
- Department of Chemistry, University of California, Berkeley 420 Latimer Hall, Berkeley, CA 94720 (USA)
- Department of Chemistry, RWTH Aachen University, Landoltweg 1 Aachen, 52074 (Germany)
| | - Matthias Loipersberger
- Department of Chemistry, University of California, Berkeley 420 Latimer Hall, Berkeley, CA 94720 (USA)
| | - Martin Head-Gordon
- Department of Chemistry, University of California, Berkeley 420 Latimer Hall, Berkeley, CA 94720 (USA)
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, MS 70A3307, Berkeley, CA 94720 (USA)
| | - F. Dean Toste
- Department of Chemistry, University of California, Berkeley 420 Latimer Hall, Berkeley, CA 94720 (USA)
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, MS 70A3307, Berkeley, CA 94720 (USA)
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6
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Costa Peluzo BMT, Kraka E. Uranium: The Nuclear Fuel Cycle and Beyond. Int J Mol Sci 2022; 23:ijms23094655. [PMID: 35563047 PMCID: PMC9101921 DOI: 10.3390/ijms23094655] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 04/13/2022] [Accepted: 04/18/2022] [Indexed: 01/01/2023] Open
Abstract
This review summarizes the recent developments regarding the use of uranium as nuclear fuel, including recycling and health aspects, elucidated from a chemical point of view, i.e., emphasizing the rich uranium coordination chemistry, which has also raised interest in using uranium compounds in synthesis and catalysis. A number of novel uranium coordination features are addressed, such the emerging number of U(II) complexes and uranium nitride complexes as a promising class of materials for more efficient and safer nuclear fuels. The current discussion about uranium triple bonds is addressed by quantum chemical investigations using local vibrational mode force constants as quantitative bond strength descriptors based on vibrational spectroscopy. The local mode analysis of selected uranium nitrides, N≡U≡N, U≡N, N≡U=NH and N≡U=O, could confirm and quantify, for the first time, that these molecules exhibit a UN triple bond as hypothesized in the literature. We hope that this review will inspire the community interested in uranium chemistry and will serve as an incubator for fruitful collaborations between theory and experimentation in exploring the wealth of uranium chemistry.
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7
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Durrant JP, Day BM, Tang J, Mansikkamäki A, Layfield RA. Dominance of Cyclobutadienyl Over Cyclopentadienyl in the Crystal Field Splitting in Dysprosium Single-Molecule Magnets. Angew Chem Int Ed Engl 2022; 61:e202200525. [PMID: 35108431 PMCID: PMC9302998 DOI: 10.1002/anie.202200525] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Indexed: 01/12/2023]
Abstract
Replacing a monoanionic cyclopentadienyl (Cp) ligand in dysprosium single‐molecule magnets (SMMs) with a dianionic cyclobutadienyl (Cb) ligand in the sandwich complexes [(η4‐Cb′′′′)Dy(η5‐C5Me4tBu)(BH4)]− (1), [(η4‐Cb′′′′)Dy(η8‐Pn†)K(THF)] (2) and [(η4‐Cb′′′′)Dy(η8‐Pn†)]− (3) leads to larger energy barriers to magnetization reversal (Cb′′′′=C4(SiMe3)4, Pn†=1,4‐di(tri‐isopropylsilyl)pentalenyl). Short distances to the Cb′′′′ ligands and longer distances to the Cp ligands in 1–3 are consistent with the crystal field splitting being dominated by the former. Theoretical analysis shows that the magnetic axes in the ground Kramers doublets of 1–3 are oriented towards the Cb′′′′ ligands. The theoretical axiality parameter and the relative axiality parameter Z and Zrel are introduced to facilitate comparisons of the SMM performance of 1–3 with a benchmark SMM. Increases in Z and Zrel when Cb′′′ replaces Cp signposts a route to SMMs with properties that could surpass leading systems.
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Affiliation(s)
- James P Durrant
- Department of Chemistry, University of Sussex Falmer, Brighton, BN1 9QR, UK
| | - Benjamin M Day
- Department of Chemistry, University of Sussex Falmer, Brighton, BN1 9QR, UK
| | - Jinkui Tang
- State Key Laboratory of Rare Earth Resource Utilization, Changchun, Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, P.R. China
| | | | - Richard A Layfield
- Department of Chemistry, University of Sussex Falmer, Brighton, BN1 9QR, UK
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8
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Wong ZR, Schramm TK, Loipersberger M, Head‐Gordon M, Toste FD. Revisiting the Bonding Model for Gold(I) Species: The Importance of Pauli Repulsion Revealed in a Gold(I)‐Cyclobutadiene Complex. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202202019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Zeng Rong Wong
- Department of Chemistry University of California, Berkeley 420 Latimer Hall Berkeley CA 94720 USA
| | - Tim K. Schramm
- Department of Chemistry University of California, Berkeley 420 Latimer Hall Berkeley CA 94720 USA
- Department of Chemistry RWTH Aachen University Landoltweg 1 52074 Aachen Germany
| | - Matthias Loipersberger
- Department of Chemistry University of California, Berkeley 420 Latimer Hall Berkeley CA 94720 USA
| | - Martin Head‐Gordon
- Department of Chemistry University of California, Berkeley 420 Latimer Hall Berkeley CA 94720 USA
- Chemical Sciences Division Lawrence Berkeley National Laboratory One Cyclotron Road, MS 70A3307 Berkeley CA 94720 USA
| | - F. Dean Toste
- Department of Chemistry University of California, Berkeley 420 Latimer Hall Berkeley CA 94720 USA
- Chemical Sciences Division Lawrence Berkeley National Laboratory One Cyclotron Road, MS 70A3307 Berkeley CA 94720 USA
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9
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Durrant JP, Day BM, Tang J, Mansikkamäki A, Layfield RA. Dominance of Cyclobutadienyl Over Cyclopentadienyl in the Crystal Field Splitting in Dysprosium Single‐Molecule Magnets. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202200525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- James P. Durrant
- Department of Chemistry University of Sussex Falmer Brighton BN1 9QR UK
| | - Benjamin M. Day
- Department of Chemistry University of Sussex Falmer Brighton BN1 9QR UK
| | - Jinkui Tang
- State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 P.R. China
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10
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Murillo J, Bhowmick R, Harriman KLM, Gomez-Torres A, Wright J, Meulenberg RW, Miró P, Metta-Magaña A, Murugesu M, Vlaisavljevich B, Fortier S. Actinide arene-metalates: ion pairing effects on the electronic structure of unsupported uranium-arenide sandwich complexes. Chem Sci 2021; 12:13360-13372. [PMID: 34777754 PMCID: PMC8528047 DOI: 10.1039/d1sc03275e] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 09/09/2021] [Indexed: 11/21/2022] Open
Abstract
Addition of [UI2(THF)3(μ-OMe)]2·THF (2·THF) to THF solutions containing 6 equiv. of K[C14H10] generates the heteroleptic dimeric complexes [K(18-crown-6)(THF)2]2[U(η6-C14H10)(η4-C14H10)(μ-OMe)]2·4THF (118C6·4THF) and {[K(THF)3][U(η6-C14H10)(η4-C14H10)(μ-OMe)]}2 (1THF) upon crystallization of the products in THF in the presence or absence of 18-crown-6, respectively. Both 118C6·4THF and 1THF are thermally stable in the solid-state at room temperature; however, after crystallization, they become insoluble in THF or DME solutions and instead gradually decompose upon standing. X-ray diffraction analysis reveals 118C6·4THF and 1THF to be structurally similar, possessing uranium centres sandwiched between bent anthracenide ligands of mixed tetrahapto and hexahapto ligation modes. Yet, the two complexes are distinguished by the close contact potassium-arenide ion pairing that is seen in 1THF but absent in 118C6·4THF, which is observed to have a significant effect on the electronic characteristics of the two complexes. Structural analysis, SQUID magnetometry data, XANES spectral characterization, and computational analyses are generally consistent with U(iv) formal assignments for the metal centres in both 118C6·4THF and 1THF, though noticeable differences are detected between the two species. For instance, the effective magnetic moment of 1THF (3.74 μB) is significantly lower than that of 118C6·4THF (4.40 μB) at 300 K. Furthermore, the XANES data shows the U LIII-edge absorption energy for 1THF to be 0.9 eV higher than that of 118C6·4THF, suggestive of more oxidized metal centres in the former. Of note, CASSCF calculations on the model complex {[U(η6-C14H10)(η4-C14H10)(μ-OMe)]2}2− (1*) shows highly polarized uranium–arenide interactions defined by π-type bonds where the metal contributions are primarily comprised by the 6d-orbitals (7.3 ± 0.6%) with minor participation from the 5f-orbitals (1.5 ± 0.5%). These unique complexes provide new insights into actinide–arenide bonding interactions and show the sensitivity of the electronic structures of the uranium atoms to coordination sphere effects. Use of Chatt metal-arene protocols with uranium leads to the synthesis of the first well-characterized, unsupported actinide–arenide sandwich complexes. The electronic structures of the actinide centres show a key sensitivity to ion pairing effects.![]()
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Affiliation(s)
- Jesse Murillo
- Department of Chemistry and Biochemistry, University of Texas at El Paso El Paso Texas 79968 USA
| | - Rina Bhowmick
- Department of Chemistry, University of South Dakota Vermillion South Dakota 57069 USA
| | - Katie L M Harriman
- Department of Chemistry and Biomolecular Sciences, University of Ottawa Ottawa Ontario K1N 6N5 Canada
| | - Alejandra Gomez-Torres
- Department of Chemistry and Biochemistry, University of Texas at El Paso El Paso Texas 79968 USA
| | - Joshua Wright
- Department of Physics, Illinois Institute of Technology Chicago Illinois 60616 USA
| | - Robert W Meulenberg
- Department of Physics and Astronomy and Frontier Institute for Research in Sensor Technologies, University of Maine Orono Maine 04469 USA
| | - Pere Miró
- Department of Chemistry, University of South Dakota Vermillion South Dakota 57069 USA
| | - Alejandro Metta-Magaña
- Department of Chemistry and Biochemistry, University of Texas at El Paso El Paso Texas 79968 USA
| | - Muralee Murugesu
- Department of Chemistry and Biomolecular Sciences, University of Ottawa Ottawa Ontario K1N 6N5 Canada
| | - Bess Vlaisavljevich
- Department of Chemistry, University of South Dakota Vermillion South Dakota 57069 USA
| | - Skye Fortier
- Department of Chemistry and Biochemistry, University of Texas at El Paso El Paso Texas 79968 USA
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11
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Abstract
The f‐block chemistry of phospholyl and arsolyl ligands, heavier p‐block analogues of substituted cyclopentadienyls (CpR, C5R5) where one or more CR groups are replaced by P or As atoms, is less developed than for lighter isoelectronic C5R5 rings. Heterocyclopentadienyl complexes can exhibit properties that complement and contrast with CpR chemistry. Given that there has been renewed interest in phospholyl and arsolyl f‐block chemistry in the last two decades, coinciding with a renaissance in f‐block solution chemistry, a review of this field is timely. Here, the syntheses of all structurally characterised examples of lanthanide and actinide phospholyl and arsolyl complexes to date are covered, including benzannulated derivatives, and together with group 3 complexes for completeness. The physicochemical properties of these complexes are reviewed, with the intention of motivating further research in this field.
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Affiliation(s)
- David P Mills
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M139PL, UK
| | - Peter Evans
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M139PL, UK
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12
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Du J, Hunger D, Seed JA, Cryer JD, King DM, Wooles AJ, van Slageren J, Liddle ST. Dipnictogen f-Element Chemistry: A Diphosphorus Uranium Complex. J Am Chem Soc 2021; 143:5343-5348. [PMID: 33792307 DOI: 10.1021/jacs.1c02482] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The first isolation and structural characterization of an f-element dinitrogen complex was reported in 1988, but an f-element complex with the first heavier group 15 homologue diphosphorus has to date remained unknown. Here, we report the synthesis of a side-on bound diphosphorus complex of uranium(IV) using a 7λ3-(dimethylamino)phosphadibenzonorbornadiene-mediated P atom transfer approach. Experimental and computational characterization reveals that the diphosphorus ligand is activated to its dianionic (P2)2- form and that in-plane U-P π-bonding dominates the bonding of the U(μ-η2:η2-P2)U unit, which is supplemented by a weak U-P interaction of δ symmetry. A preliminary reactivity study demonstrates conversion of this diphosphorus complex to unprecedented uranium cyclo-P3 complexes, suggesting in situ generation of transient, reactive phosphido species.
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Affiliation(s)
- Jingzhen Du
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
| | - David Hunger
- Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
| | - John A Seed
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
| | - Jonathan D Cryer
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
| | - David M King
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, U.K
| | - Ashley J Wooles
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
| | - Joris van Slageren
- Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
| | - Stephen T Liddle
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
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13
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Tsoureas N, Mansikkamäki A, Layfield RA. Synthesis, bonding properties and ether activation reactivity of cyclobutadienyl-ligated hybrid uranocenes. Chem Sci 2021; 12:2948-2954. [PMID: 34164062 PMCID: PMC8179396 DOI: 10.1039/d0sc05199c] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 01/07/2021] [Indexed: 11/21/2022] Open
Abstract
A series of hybrid uranocenes consisting of uranium(iv) sandwiched between cyclobutadienyl (Cb) and cyclo-octatetraenyl (COT) ligands has been synthesized, structurally characterized and studied computationally. The dimetallic species [(η4-Cb'''')(η8-COT)U(μ:η2:η8-COT)U(THF)(η4-Cb'''')] (1) forms concomitantly with, and can be separated from, monometallic [(η4-Cb'''')U(THF)(η8-COT)] (2) (Cb'''' = 1,2,3,4-tetrakis(trimethylsilyl)cyclobutadienyl, COT = cyclo-octatetraenyl). In toluene solution at room temperature, 1 dissociates into 2 and the unsolvated uranocene [(η4-Cb'''')U(η8-COT)] (3). By applying a high vacuum, both 1 and 2 can be converted directly into 3. Using bulky silyl substituents on the COT ligand allowed isolation of base-free [(η4-Cb'''')U{η8-1,4-(iPr3Si)2C8H6}] (4), with compounds 3 and 4 being new members of the bis(annulene) family of actinocenes and the first to contain a cyclobutadienyl ligand. Computational studies show that the bonding in the hybrid uranocenes 3 and 4 has non-negligible covalency. New insight into actinocene bonding is provided by the complementary interactions of the different ligands with uranium, whereby the 6d orbitals interact most strongly with the cyclobutadienyl ligand and the 5f orbitals do so with the COT ligands. The redox-neutral activation of diethyl ether by [(η4-Cb'''')U(η8-C8H8)] is also described and represents a uranium-cyclobutadienyl cooperative process, potentially forming the basis of further small-molecule activation chemistry.
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Affiliation(s)
- Nikolaos Tsoureas
- Department of Chemistry, School of Life Sciences, University of Sussex Brighton BN1 9QJ UK
| | | | - Richard A Layfield
- Department of Chemistry, School of Life Sciences, University of Sussex Brighton BN1 9QJ UK
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