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Ordoñez O, Yu X, Wu G, Autschbach J, Hayton TW. Quantifying Actinide-Carbon Bond Covalency in a Uranyl-Aryl Complex Utilizing Solution 13C NMR Spectroscopy. Inorg Chem 2024; 63:9427-9433. [PMID: 37788299 DOI: 10.1021/acs.inorgchem.3c02440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Reaction of [UO2Cl2(THF)2]2 with in situ generated LiFmes (FmesH = 1,3,5-(CF3)3C6H3) in Et2O resulted in the formation of the uranyl aryl complexes [Li(THF)3][UO2(Fmes)3] ([Li(THF)3][1]) and [Li(Et2O)3(THF)][UO2(Fmes)3] ([Li(Et2O)3(THF)][1]) in good to moderate yields after crystallization from hexanes and Et2O, respectively. Both complexes were characterized by X-ray crystallography and NMR spectroscopy. DFT calculations reveal that the Cispo resonance in [1]- exhibits a deshielding of 51 ppm from spin-orbit coupling effects originating at uranium, which indicates an appreciable covalency in the U-C bonding interaction.
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Affiliation(s)
- Osvaldo Ordoñez
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Xiaojuan Yu
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, United States
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
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2
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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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3
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Watson LJ, Hill AF. Stable cyclopropenylvinyl ligands via insertion into a transient cyclopropenyl metal bond. Dalton Trans 2024; 53:3629-3637. [PMID: 38289268 DOI: 10.1039/d3dt03997h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024]
Abstract
Treatment of the rhodium pincer complexes [RhCl(RPm)] (RPm = N,N'-bis(di-R-phosphinomethyl)perimidinylidene, R = Ph, Cy) with triphenylcyclopropenium hexafluorophosphate affords rhodacyclobutadiene complexes. These in turn react with activated alkynes (RCCCO2Me, R = H, CO2Me) to afford unusually stable cyclopropenylvinyls, implicating the intermediacy of σ-cyclopropenyl isomers. In contrast, treatment of [RhCl{py(NHPtBu2)2-2,6}] with the same reagent instead results in double functionalisation (SEAr) at the pincer backbone.
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Affiliation(s)
- Lachlan J Watson
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory, ACT 2601, Australia.
| | - Anthony F Hill
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory, ACT 2601, Australia.
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4
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Baker CF, Seed JA, Adams RW, Lee D, Liddle ST. 13C carbene nuclear magnetic resonance chemical shift analysis confirms Ce IV[double bond, length as m-dash]C double bonding in cerium(iv)-diphosphonioalkylidene complexes. Chem Sci 2023; 15:238-249. [PMID: 38131084 PMCID: PMC10732143 DOI: 10.1039/d3sc04449a] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 11/27/2023] [Indexed: 12/23/2023] Open
Abstract
Diphosphonioalkylidene dianions have emerged as highly effective ligands for lanthanide and actinide ions, and the resulting formal metal-carbon double bonds have challenged and developed conventional thinking about f-element bond multiplicity and covalency. However, f-element-diphosphonioalkylidene complexes can be represented by several resonance forms that render their metal-carbon double bond status unclear. Here, we report an experimentally-validated 13C Nuclear Magnetic Resonance computational assessment of two cerium(iv)-diphosphonioalkylidene complexes, [Ce(BIPMTMS)(ODipp)2] (1, BIPMTMS = {C(PPh2NSiMe3)2}2-; Dipp = 2,6-diisopropylphenyl) and [Ce(BIPMTMS)2] (2). Decomposing the experimental alkylidene chemical shifts into their corresponding calculated shielding (σ) tensor components verifies that these complexes exhibit Ce[double bond, length as m-dash]C double bonds. Strong magnetic coupling of Ce[double bond, length as m-dash]C σ/π* and π/σ* orbitals produces strongly deshielded σ11 values, a characteristic hallmark of alkylidenes, and the largest 13C chemical shift tensor spans of any alkylidene complex to date (1, 801 ppm; 2, 810 ppm). In contrast, the phosphonium-substituent shielding contributions are much smaller than the Ce[double bond, length as m-dash]C σ- and π-bond components. This study confirms significant Ce 4f-orbital contributions to the Ce[double bond, length as m-dash]C bonding, provides further support for a previously proposed inverse-trans-influence in 2, and reveals variance in the 4f spin-orbit contributions that relate to the alkylidene hybridisation. This work thus confirms the metal-carbon double bond credentials of f-element-diphosphonioalkylidenes, providing quantified benchmarks for understanding diphosphonioalkylidene bonding generally.
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Affiliation(s)
- Cameron F Baker
- Department of Chemistry, The University of Manchester Oxford Road Manchester M13 9PL UK
| | - John A Seed
- Department of Chemistry, The University of Manchester Oxford Road Manchester M13 9PL UK
| | - Ralph W Adams
- Department of Chemistry, The University of Manchester Oxford Road Manchester M13 9PL UK
| | - Daniel Lee
- Department of Chemical Engineering, The University of Manchester Oxford Road Manchester M13 9PL UK
| | - Stephen T Liddle
- Department of Chemistry, The University of Manchester Oxford Road Manchester M13 9PL UK
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5
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Du J, Hurd J, Seed JA, Balázs G, Scheer M, Adams RW, Lee D, Liddle ST. 31P Nuclear Magnetic Resonance Spectroscopy as a Probe of Thorium-Phosphorus Bond Covalency: Correlating Phosphorus Chemical Shift to Metal-Phosphorus Bond Order. J Am Chem Soc 2023; 145:21766-21784. [PMID: 37768555 PMCID: PMC10571089 DOI: 10.1021/jacs.3c02775] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Indexed: 09/29/2023]
Abstract
We report the use of solution and solid-state 31P Nuclear Magnetic Resonance (NMR) spectroscopy combined with Density Functional Theory calculations to benchmark the covalency of actinide-phosphorus bonds, thus introducing 31P NMR spectroscopy to the investigation of molecular f-element chemical bond covalency. The 31P NMR data for [Th(PH2)(TrenTIPS)] (1, TrenTIPS = {N(CH2CH2NSiPri3)3}3-), [Th(PH)(TrenTIPS)][Na(12C4)2] (2, 12C4 = 12-crown-4 ether), [{Th(TrenTIPS)}2(μ-PH)] (3), and [{Th(TrenTIPS)}2(μ-P)][Na(12C4)2] (4) demonstrate a chemical shift anisotropy (CSA) ordering of (μ-P)3- > (═PH)2- > (μ-PH)2- > (-PH2)1- and for 4 the largest CSA for any bridging phosphido unit. The B3LYP functional with 50% Hartree-Fock mixing produced spin-orbit δiso values that closely match the experimental data, providing experimentally benchmarked quantification of the nature and extent of covalency in the Th-P linkages in 1-4 via Natural Bond Orbital and Natural Localized Molecular Orbital analyses. Shielding analysis revealed that the 31P δiso values are essentially only due to the nature of the Th-P bonds in 1-4, with largely invariant diamagnetic but variable paramagnetic and spin-orbit shieldings that reflect the Th-P bond multiplicities and s-orbital mediated transmission of spin-orbit effects from Th to P. This study has permitted correlation of Th-P δiso values to Mayer bond orders, revealing qualitative correlations generally, but which should be examined with respect to specific ancillary ligand families rather than generally to be quantitative, reflecting that 31P δiso values are a very sensitive reporter due to phosphorus being a soft donor that responds to the rest of the ligand field much more than stronger, harder donors like nitrogen.
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Affiliation(s)
- Jingzhen Du
- Department
of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K.
| | - Joseph Hurd
- Department
of Chemical Engineering, The University
of Manchester, Oxford Road, Manchester, M13 9PL, U.K.
| | - John A. Seed
- Department
of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K.
| | - Gábor Balázs
- Institute
of Inorganic Chemistry, University of Regensburg, Universitätsstr. 31, 93053 Regensburg, Germany
| | - Manfred Scheer
- Institute
of Inorganic Chemistry, University of Regensburg, Universitätsstr. 31, 93053 Regensburg, Germany
| | - Ralph W. Adams
- Department
of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K.
| | - Daniel Lee
- Department
of Chemical Engineering, 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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Nguyen TH, Paul EL, Lukens WW, Hayton TW. Evaluating f-Orbital Participation in the U V═E Multiple Bonds of [U(E)(NR 2) 3] (E = O, NSiMe 3, NAd; R = SiMe 3). Inorg Chem 2023; 62:6447-6457. [PMID: 37053543 DOI: 10.1021/acs.inorgchem.3c00455] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/15/2023]
Abstract
The reaction of 1 equiv of 1-azidoadamantane with [UIII(NR2)3] (R = SiMe3) in Et2O results in the formation of [UV(NR2)3(NAd)] (1, Ad = 1-adamantyl) in good yields. The electronic structure of 1, as well as those of the related U(V) complexes, [UV(NR2)3(NSiMe3)] (2) and [UV(NR2)3(O)] (3), were analyzed with EPR spectroscopy, SQUID magnetometry, NIR-visible spectroscopy, and crystal field modeling. This analysis revealed that, within this series of complexes, the steric bulk of the E2- (E═O, NR) ligand is the most important factor in determining the electronic structure. In particular, the increasing steric bulk of this ligand, on moving from O2- to [NAd]2-, results in increasing U═E distances and E-U-Namide angles. These changes have two principal effects on the resulting electronic structure: (1) the increasing U═E distances decreases the energy of the fσ orbital, which is primarily σ* with respect to the U═E bond, and (2) the increasing E-U-Namide angles increases the energy of fδ, due to increasing antibonding interactions with the amide ligands. As a result of the latter change, the electronic ground state for complexes 1 and 2 is primarily fφ in character, whereas the ground state for complex 3 is primarily fδ.
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Affiliation(s)
- Thien H Nguyen
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Edward L Paul
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Wayne W Lukens
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
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7
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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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Ordoñez O, Yu X, Wu G, Autschbach J, Hayton TW. Assessing the 4f Orbital Participation in the Ln–C Bonds of [Li(THF) 4][Ln(C 6Cl 5) 4] (Ln = La, Ce). Inorg Chem 2022; 61:15138-15143. [DOI: 10.1021/acs.inorgchem.2c02304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Osvaldo Ordoñez
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Xiaojuan Yu
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, United States
| | - Trevor W. Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
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