1
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Li S, Schröder M, Prudlik A, Shi X, Spannenberg A, Rabeah J, Francke R, Corzilius B, Reiß F, Beweries T. A General Concept for the Electronic and Steric Modification of 1-Metallacyclobuta-2,3-dienes: A Case Study of Group 4 Metallocene Complexes. Chemistry 2024; 30:e202400708. [PMID: 38529695 DOI: 10.1002/chem.202400708] [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: 02/21/2024] [Revised: 03/22/2024] [Accepted: 03/25/2024] [Indexed: 03/27/2024]
Abstract
The synthesis of group 4 metal 1-metallacyclobuta-2,3-dienes as organometallic analogues of elusive 1,2-cyclobutadiene has so far been limited to SiMe3 substituted examples. We present the synthesis of two Ph substituted dilithiated ligand precursors for the preparation of four new 1-metallacyclobuta-2,3-dienes [rac-(ebthi)M] (M=Ti, Zr; ebthi=1,2-ethylene-1,10-bis(η5-tetrahydroindenyl)). The organolithium compounds [Li2(RC3Ph)] (1 b: R=Ph, 1 c: R=SiMe3) as well as the metallacycles of the general formula [rac-(ebthi)M(R1C3R2)] (2 b: M=Ti, R1=R2=Ph, 2 c: M=Ti, R1=Ph, R2=SiMe3; 3 b: M=Zr, R1=R2=Ph; 3 c: M=Zr, R1=Ph, R2=SiMe3) were fully characterised. Single crystal X-ray diffraction and quantum chemical bond analysis of the Ti and Zr complexes reveal ligand influence on the biradicaloid character of the titanocene complexes. X-band EPR spectroscopy of structurally similar Ti complexes [rac-(ebthi)Ti(Me3SiC3SiMe3)] (2 a), 2 b, and 2 c was carried out to evaluate the accessibility of an EPR active triplet state. Cyclic voltammetry shows that introduction of Ph groups renders the complexes easier to reduce. 13C CPMAS NMR analysis provides insights into the cause of the low field shift of the resonances of metal-bonded carbon atoms and provides evidence of the absence of the β-C-Ti interaction.
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Affiliation(s)
- Sihan Li
- Leibniz Institute for Catalysis, Albert-Einstein-Str. 29a, 18059, Rostock, Germany
| | - Mirjam Schröder
- Leibniz Institute for Catalysis, Albert-Einstein-Str. 29a, 18059, Rostock, Germany
- University of Rostock, Institute of Chemistry, 18059, Rostock, Germany
- University of Rostock, Department LL&M, 18059, Rostock, Germany
| | - Adrian Prudlik
- Leibniz Institute for Catalysis, Albert-Einstein-Str. 29a, 18059, Rostock, Germany
- University of Rostock, Institute of Chemistry, 18059, Rostock, Germany
| | - Xinzhe Shi
- Leibniz Institute for Catalysis, Albert-Einstein-Str. 29a, 18059, Rostock, Germany
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, P. R. China
| | - Anke Spannenberg
- Leibniz Institute for Catalysis, Albert-Einstein-Str. 29a, 18059, Rostock, Germany
| | - Jabor Rabeah
- Leibniz Institute for Catalysis, Albert-Einstein-Str. 29a, 18059, Rostock, Germany
| | - Robert Francke
- Leibniz Institute for Catalysis, Albert-Einstein-Str. 29a, 18059, Rostock, Germany
| | - Björn Corzilius
- Leibniz Institute for Catalysis, Albert-Einstein-Str. 29a, 18059, Rostock, Germany
- University of Rostock, Institute of Chemistry, 18059, Rostock, Germany
- University of Rostock, Department LL&M, 18059, Rostock, Germany
| | - Fabian Reiß
- Leibniz Institute for Catalysis, Albert-Einstein-Str. 29a, 18059, Rostock, Germany
| | - Torsten Beweries
- Leibniz Institute for Catalysis, Albert-Einstein-Str. 29a, 18059, Rostock, Germany
- University of Rostock, Department LL&M, 18059, Rostock, Germany
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2
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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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3
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Li T, Heng Y, Wang D, Hou G, Zi G, Ding W, Walter MD. Uranium versus Thorium: A Case Study on a Base-Free Terminal Uranium Imido Metallocene. Inorg Chem 2024; 63:9487-9510. [PMID: 38048266 DOI: 10.1021/acs.inorgchem.3c03356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/06/2023]
Abstract
The structure of and bonding in two base-free terminal actinide imido metallocenes, [η5-1,2,4-(Me3C)3C5H2]2An═N(p-tolyl) (An = U (1), Th (1')) are compared and connected to their individual reactivity. While structurally rather similar, the U(IV) derivative 1 is slightly more sterically crowded. Furthermore, density functional theory (DFT) studies imply that the 5f orbital contribution to the bonding within the individual actinide imido An═N(p-tolyl) moieties is significantly larger for 1 than for 1', which makes the bonds between the [η5-1,2,4-(Me3C)3C5H2]2U2+ and [(p-tolyl)N]2- fragments more covalent. Therefore, steric and electronic factors impact the reactivity of these imido complexes. For example, complex 1 is inert toward internal alkynes, but it readily forms Lewis base adducts [η5-1,2,4-(Me3C)3C5H2]2U═N(p-tolyl)(L) (L = OPMe3 (6), dmap (9), PhCN (14), and 2,6-Me2PhNC (17)) with Me3PO, 4-dimethylaminopyridine (dmap), nitrile, PhCN, or isonitrile 2,6-Me2PhNC. It may also react as a nucleophile or undergo a [2 + 2] cycloaddition with CS2, isothiocyanates, thio-ketones, ketones, lactides, and acyl nitriles, forming the four- or five-membered metallaheteroacycles, terminal sulfido, or oxido complexes, and cyanide amidate complexes, respectively. In contrast, after the addition of aldehyde p-tolylCHO, the tetranuclear complex [η5-1,2,4-(Me3C)3C5H2]4[OCH(p-tolyl)CH(p-tolyl)O]2U4O4 (10) is isolated. However, while 1 is unreactive toward dicyclohexylcarbodiimide (DCC), an equilibrium exists in benzene solution between N,N'-diisopropylcarbodiimide (DIC), 1, and the four-membered metallaheterocycle [η5-1,2,4-(Me3C)3C5H2]2U[N(p-tolyl)C(═NiPr)N(iPr)] (12). Furthermore, 1 may also engage in single- and two-electron transfer processes. It is singly oxidized by Ph3CN3, CuI, Ph2S2, and Ph2Se2, yielding the uranium(V) imido complexes [η5-1,2,4-(Me3C)3C5H2]2U═N(p-tolyl)(X) (X = N3 (20), I (22), PhS (23), and PhSe (24)), or is doubly oxidized by organic azides (RN3) and 9-diazofluorene, forming the uranium(VI) bis-imido metallocenes [η5-1,2,4-(Me3C)3C5H2]2U═N(p-tolyl)(=NR) (R = p-tolyl (18), mesityl (19)) and [η5-1,2,4-(Me3C)3C5H2]2U=N(p-tolyl)[=NN=(9-C13H8)] (21), respectively.
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Affiliation(s)
- Tongyu Li
- Department of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Yi Heng
- Department of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Dongwei Wang
- Department of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Guohua Hou
- Department of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Guofu Zi
- Department of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Wanjian Ding
- Department of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Marc D Walter
- Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
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4
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Hertler PR, Yu X, Brower JD, Nguyen TAD, Wu G, Autschbach J, Hayton TW. Exploring Spin-Orbit Effects in a [Cu 6Tl] + Nanocluster Featuring an Uncommon Tl-H Interaction. Chemistry 2024; 30:e202400390. [PMID: 38381600 DOI: 10.1002/chem.202400390] [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: 01/29/2024] [Revised: 02/19/2024] [Accepted: 02/21/2024] [Indexed: 02/23/2024]
Abstract
Reaction of [CuH(PPh3)]6 with 1 equiv. of Tl(OTf) results in formation of [Cu6TlH6(PPh3)6][OTf] ([1]OTf]), which can be isolated in good yields. Variable-temperature 1H NMR spectroscopy, in combination with density functional theory (DFT) calculations, confirms the presence of a rare Tl-H orbital interaction. According to DFT, the 1H chemical shift of the Tl-adjacent hydride ligands of [1]+ includes 7.7 ppm of deshielding due to spin-orbit effects from the heavy Tl atom. This study provides valuable new insights into a rare class of metal hydrides, given that [1][OTf] is only the third isolable species reported to contain a Tl-H interaction.
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Affiliation(s)
- Phoebe R Hertler
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, 93106
| | - Xiaojuan Yu
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY, 14260
| | - Jordan D Brower
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, 93106
| | - Thuy-Ai D Nguyen
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, 93106
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, 93106
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY, 14260
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, 93106
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5
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Kakiuchi Y, Karmakar PS, Roudin J, Tonks IA, Copéret C. Bonding and Reactivity of d 0 Transition Metal Imido Complexes Encoded in Their 15N NMR Signatures. J Am Chem Soc 2024; 146:9860-9870. [PMID: 38534051 PMCID: PMC11059434 DOI: 10.1021/jacs.3c14723] [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] [Indexed: 03/28/2024]
Abstract
Terminal imido complexes containing metal-nitrogen multiple bonds have been widely used in organometallic chemistry and homogeneous catalysis. The role of terminal imido ligands spans from reactive sites to spectator motifs, largely depending on the nature of the metal center and its specific coordination sphere. Aiming at identifying reactivity descriptors for M-N multiple bonds, we herein explore solid-state 15N NMR spectroscopy (ssNMR) on early transition metal terminal imido complexes augmented by computational studies and show that the asymmetry parameter, κ (skew, 1 ≥ κ ≥ -1), readily available from experiments or calculations, is diagnostic for the reactivity of M-N multiple bonds in imido complexes. While inert imido ligands exhibit skew values (κ) close to 1, highly reactive imido moieties display significantly lower skew values (κ ≪ 1) as found in metallocene or bis-imido complexes. Natural chemical shielding analysis shows that skew values away from 1 are associated with an asymmetric development of π-orbitals around the M-N multiple bond of the imido moiety, with a larger double-bond character for reactive imido. Notably, this descriptor does not directly relate to the M-N-C bond angle, illustrating the shortcoming of evaluating bonding and hybridization from geometrical parameters alone. Overall, this descriptor enables to obtain direct experimental evidence for the π-loading effect seen in bis(imido) and related complexes, thus explaining their bonding/reactivity.
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Affiliation(s)
- Yuya Kakiuchi
- Department of Chemistiy and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 2, CH-8093 Zürich, Switzerland
| | - Partha Sarathi Karmakar
- Department of Chemistry, University of Minnesota–Twin Cities, Minneapolis, Minnesota 55455, United States
| | - Jérémy Roudin
- Department of Chemistiy and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 2, CH-8093 Zürich, Switzerland
| | - Ian A. Tonks
- Department of Chemistry, University of Minnesota–Twin Cities, Minneapolis, Minnesota 55455, United States
| | - Christophe Copéret
- Department of Chemistiy and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 2, CH-8093 Zürich, Switzerland
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6
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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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7
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Park S, Walter ED, Soderquist CZ, Sinkov SI, Cho H. Temperature Dependence of Nuclear Quadrupole Resonance and the Observation of Metal-Ligand Covalency in Actinide Complexes: 35Cl in Cs 2UO 2Cl 4. J Phys Chem A 2023; 127:8347-8353. [PMID: 37769184 DOI: 10.1021/acs.jpca.3c04657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/30/2023]
Abstract
We report a study of the temperature dependence of 35Cl nuclear quadrupole resonance (NQR) transition energies and spin-lattice relaxation times (T1) for 235U-depleted dicesium uranyl tetrachloride (Cs2UO2Cl4) aimed at elucidating electronic interactions between the uranium center and atoms in the equatorial plane of the UO22+ ion. The transition frequency decreases slowly with temperature below 75 K and with a more rapid linear dependence above this temperature. The spin-lattice relaxation time becomes shorter with temperature, and as temperatures increase, the T1 decrease becomes nearly quadratic. The observed trends are reproduced by a model that assumes phonon-induced fluctuations of the electric field gradient tensor and partial electron delocalization from Cl to U. The fit of the theoretical model to experimental data allows a Debye temperature of 96 K to be estimated. The generalization of this approach to investigations of covalency in actinide-ligand bonding is examined.
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Affiliation(s)
- Sejun Park
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Eric D Walter
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Chuck Z Soderquist
- Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Sergey I Sinkov
- Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Herman Cho
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
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8
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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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9
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Li T, Wang D, Heng Y, Hou G, Zi G, Walter MD. Reactivity of a Lewis base-supported uranium terminal imido metallocene towards small molecules. Dalton Trans 2023; 52:13618-13630. [PMID: 37698550 DOI: 10.1039/d3dt02165c] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/13/2023]
Abstract
The Lewis base-supported uranium terminal imido metallocene [η5-1,2,4-(Me3Si)3C5H2]2UN(p-tolyl)(dmap) (1) readily reacts with various small molecules such as internal alkynes, isothiocyanates, thioketones, amidates, organic nitriles and imines, chlorosilanes, copper iodide, diphenyl disulfide, organic azides and diazoalkane derivatives. For example, treatment of 1 with PhCCCCPh and PhNCS forms metallaheterocycles originating from a [2 + 2] cycloaddition to yield [η5-1-(p-tolyl)NC(Ph)CHCC(Ph)CH2Si(Me)2-2,4-(Me3Si)2C5H2][η5-1,2,4-(Me3Si)3C5H2]U (2) and [η5-1,2,4-(Me3Si)3C5H2]2U[N(p-tolyl)C(NPh)S](dmap) (3), respectively. The reaction of 1 with the thioketone Ph2CS forms the known uranium sulfido complex [η5-1,2,4-(Me3Si)3C5H2]2US(dmap) (4), which reacts with a second molecule of Ph2CS to give the disulfido compound [η5-1,2,4-(Me3Si)3C5H2]2U(S2CPh2) (5). The imido moiety also promotes deprotonation reactions as illustrated in the reactions with the amide PhCONH(p-tolyl), the nitrile PhCH2CN and the imine (p-tolyl)2CNH to form the bis-amidate [η5-1,2,4-(Me3Si)3C5H2]2U[OC(Ph)N(p-tolyl)]2 (7), and the iminato complexes [η5-1,2,4-(Me3Si)3C5H2]2U[N(p-tolyl)C(CH2Ph)NH](NCCHPh) (8) and [η5-1,2,4-(Me3Si)3C5H2]2U[NH(p-tolyl)][NC(p-tolyl)2] (9), respectively. Addition of PhSiH2Cl to 1 yields [η5-1,2,4-(Me3Si)3C5H2]2U(Cl)[N(p-tolyl)SiH2Ph] (10). In contrast, the uranium(V) imido complexes [η5-1,2,4-(Me3Si)3C5H2]2UN(p-tolyl)(I) (11) and [η5-1,2,4-(Me3Si)3C5H2]2UN(p-tolyl)(SPh) (12), may be isolated upon addition of CuI or Ph2S2 to 1, respectively. Uranium(VI) bis-imido metallocenes [η5-1,2,4-(Me3Si)3C5H2]2UN(p-tolyl)(NR) (R = p-tolyl (13), mesityl (14)) and [η5-1,2,4-(Me3Si)3C5H2]2UN(p-tolyl)[NN(9-C13H8)] (15) are accessible from 1 on exposure to RN3 (R = p-tolyl, mesityl) and 9-diazofluorene, respectively. Complexes 2, 3, 5, and 7-15 were characterized by various spectroscopic techniques and, in addition, compounds 2, 3, 5, and 7-13 were structurally authenticated by single-crystal X-ray diffraction analyses.
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Affiliation(s)
- Tongyu Li
- Department of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Dongwei Wang
- Department of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Yi Heng
- Department of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Guohua Hou
- Department of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Guofu Zi
- Department of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Marc D Walter
- Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany.
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10
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Keener M, Maria L, Mazzanti M. Progress in the chemistry of molecular actinide-nitride compounds. Chem Sci 2023; 14:6493-6521. [PMID: 37350843 PMCID: PMC10283502 DOI: 10.1039/d3sc01435e] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Accepted: 05/05/2023] [Indexed: 06/24/2023] Open
Abstract
The chemistry of actinide-nitrides has witnessed significant advances in the last ten years with a large focus on uranium and a few breakthroughs with thorium. Following the early discovery of the first terminal and bridging nitride complexes, various synthetic routes to uranium nitrides have since been identified, although the range of ligands capable of stabilizing uranium nitrides still remains scarce. In particular, both terminal- and bridging-nitrides possess attractive advantages for potential reactivity, especially in light of the recent development of uranium complexes for dinitrogen reduction and functionalization. The first molecular thorium bridged-nitride complexes have also been recently identified, anticipating the possibility of expanding nitride chemistry not only to low-valent thorium, but also to the transuranic elements.
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Affiliation(s)
- Megan Keener
- Group of Coordination Chemistry, Institute of Chemical Sciences and Engineering - ISIC, Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Leonor Maria
- Centro de Química Estrutural, Institute of Molecular Sciences, Instituto Superior Técnico, Universidade de Lisboa 2695-066 Bobadela Portugal
| | - Marinella Mazzanti
- Group of Coordination Chemistry, Institute of Chemical Sciences and Engineering - ISIC, Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
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11
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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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12
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Arteaga A, Nicholas AD, Ducati LC, Autschbach J, Surbella RG. Americium Oxalate: An Experimental and Computational Investigation of Metal-Ligand Bonding. Inorg Chem 2023; 62:4814-4822. [PMID: 36920249 DOI: 10.1021/acs.inorgchem.2c03976] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
A novel actinide-containing coordination polymer, [Am(C2O4)(H2O)3Cl] (Am-1), has been synthesized and structurally characterized. The crystallographic analysis reveals that the structure is two-dimensional and comprised of pseudo-dimeric Am3+ nodes that are bridged by oxalate ligands to form sheets. Each metal center is nine-coordinate, forming a distorted capped square antiprism geometry with a C1 symmetry, and features bound oxalate, aqua, and chloro ligands. The Am3+-ligand bonds were probed computationally using the quantum theory of atoms in molecules nd natural localized molecular orbital approaches to investigate the underlying mechanisms and hybrid atomic orbital contributions therein. The analyses indicate that the bonds within Am-1 are predominantly ionic and the 5f shell of the Am3+ metal centers does not add a significant covalent contribution to the bonds. Our bonding assessment is supported by measurements on the optical properties of Am-1 using diffuse reflectance and photoluminescence spectroscopies. The position of the principal absorption band at 507 nm (5L6' ← 7F0') is notable because it is consistent with previously reported americium oxalate complexes in solution, indicating similarities in the electronic structure and ionic bonding. Compound Am-1 is an active phosphor, featuring strong bright-blue oxalate-based luminescence with no evidence of metal-centered emission.
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Affiliation(s)
- Ana Arteaga
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354, United States
| | - Aaron D Nicholas
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354, United States
| | - Lucas C Ducati
- Department of Fundamental Chemistry Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, São Paulo 05508-000, Brazil
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, State University of New York, 312 Natural Sciences Complex, Buffalo, New York 14260, United States
| | - Robert G Surbella
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354, United States
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13
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Wilson HH, Yu X, Cheisson T, Smith PW, Pandey P, Carroll PJ, Minasian SG, Autschbach J, Schelter EJ. Synthesis and Characterization of a Bridging Cerium(IV) Nitride Complex. J Am Chem Soc 2023; 145:781-786. [PMID: 36603174 DOI: 10.1021/jacs.2c12145] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Complexes featuring lanthanide-ligand multiple bonds are rare and highly reactive. They are important synthetic targets to understand 4f/5d-bonding in comparison to d-block and actinide congeners. Herein, the isolation and characterization of a bridging cerium(IV)-nitride complex: [(TriNOx)Ce(Li2μ-N)Ce(TriNOx)][BArF4] is reported, the first example of a molecular cerium-nitride. The compound was isolated by deprotonating a monometallic cerium(IV)-ammonia complex: [CeIV(NH3)(TriNOx)][BArF4]. The average Ce═N bond length of [(TriNOx)Ce(Li2μ-N)Ce(TriNOx)][BArF4] was 2.117(3) Å. Vibrational studies of the 15N-isotopomer exhibited a shift of the Ce═N═Ce asymmetric stretch from ν = 644 cm-1 to 640 cm-1, and X-ray spectroscopic studies confirm the +4 oxidation state of cerium. Computational analyses showed strong involvement of the cerium 4f shell in bonding with overall 16% and 11% cerium weight in the σ- and π-bonds of the Ce═N═Ce fragment, respectively.
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Affiliation(s)
- Henry H Wilson
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Xiaojuan Yu
- Department of Chemistry, University of Buffalo, 732 Natural Sciences Complex, Buffalo, New York 14260, United States
| | - Thibault Cheisson
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Patrick W Smith
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Pragati Pandey
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Patrick J Carroll
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Stefan G Minasian
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Jochen Autschbach
- Department of Chemistry, University of Buffalo, 732 Natural Sciences Complex, Buffalo, New York 14260, 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
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14
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Fernández-Alarcón A, Autschbach J. Relativistic Density Functional NMR Tensors Analyzed with Spin-free Localized Molecular Orbitals. Chemphyschem 2023; 24:e202200667. [PMID: 36169984 DOI: 10.1002/cphc.202200667] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 09/21/2022] [Indexed: 01/07/2023]
Abstract
The implementation of fast relativistic methods based on density functional theory, in conjunction with localized molecular orbital (LMO) based analysis, allows straightforward interpretations of NMR parameters in terms of contributions from core shells, lone pairs, and bonds, for compounds containing elements from across the periodic table. We present a conceptual review of a frequently used LMO analysis of NMR parameters calculated in the presence of spin-orbit interactions and other relativistic effects. An accompanying example focuses on the 15 N shielding in a heavy metal complex.
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Affiliation(s)
- Alberto Fernández-Alarcón
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY 14260-3000, USA
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY 14260-3000, USA
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15
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Hastings AM, Ray D, Hanna SL, Jeong W, Chen Z, Oliver AG, Gagliardi L, Farha OK, Hixon AE. Leveraging Nitrogen Linkages in the Formation of a Porous Thorium-Organic Nanotube Suitable for Iodine Capture. Inorg Chem 2022; 61:9480-9492. [PMID: 35700478 DOI: 10.1021/acs.inorgchem.2c00427] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the synthesis, characterization, and iodine capture application of a novel thorium-organic nanotube, TSN-626, [Th6O4(OH)4(C6H4NO2)7(CHO2)5(H2O)3]·3H2O. The classification as a metal-organic nanotube (MONT) distinguishes it as a rare and reduced dimensionality subset of metal-organic frameworks (MOFs); the structure is additionally hallmarked by low node connectivity. TSN-626 is composed of hexameric thorium secondary building units and mixed O/N-donor isonicotinate ligands that demonstrate selective ditopicity, yielding both terminating and bridging moieties. Because hard Lewis acid tetravalent metals have a propensity to bind with electron donors of rival hardness (e.g., carboxylate groups), such Th-N coordination in a MOF is uncommon. However, the formation of key structural Th-N bonds in TSN-626 cap some of the square antiprismatic metal centers, a position usually occupied by terminal water ligands. TSN-626 was characterized by using complementary analytical and computational techniques: X-ray diffraction, vibrational spectroscopy, N2 physisorption isotherms, and density functional theory. TSN-626 satisfies design aspects for the chemisorption of iodine. The synergy between accessibility through pores, vacancies at the metal-oxo nodes, and pendent N-donor sites allowed a saturated iodine loading of 955 mg g-1 by vapor methods. The crystallization of TSN-626 diversifies actinide-MOF linker selection to include soft electron donors, and these Th-N linkages can be leveraged for the investigation of metal-to-ligand bonding and unconventional topological expressions.
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Affiliation(s)
- Ashley M Hastings
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, 301 Stinson-Remick, Notre Dame, Indiana 46556, United States
| | - Debmalya Ray
- Department of Chemistry, Chemical Theory Center and Minnesota Supercomputing Institute, University of Minnesota, 207 Pleasant Street Southeast, Minneapolis, Minnesota 55455, United States
| | - Sylvia L Hanna
- Department of Chemistry, International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - WooSeok Jeong
- Department of Chemistry, Chemical Theory Center and Minnesota Supercomputing Institute, University of Minnesota, 207 Pleasant Street Southeast, Minneapolis, Minnesota 55455, United States
| | - Zhijie Chen
- Department of Chemistry, International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Allen G Oliver
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Laura Gagliardi
- Department of Chemistry, Pritzker School of Molecular Engineering, James Franck Institute, Chicago Center for Theoretical Chemistry, The University of Chicago, 5735 S. Ellis Ave., Chicago, Illinois 60637, United States.,Argonne National Laboratory, 97000 S. Cass Ave., Lemont, Illinois 60439, United States
| | - Omar K Farha
- Department of Chemistry, International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Amy E Hixon
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, 301 Stinson-Remick, Notre Dame, Indiana 46556, United States
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16
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King DM, Atkinson BE, Chatelain L, Gregson M, Seed JA, Wooles AJ, Kaltsoyannis N, Liddle ST. Uranium-nitride chemistry: uranium-uranium electronic communication mediated by nitride bridges. Dalton Trans 2022; 51:8855-8864. [PMID: 35622422 PMCID: PMC9171730 DOI: 10.1039/d2dt00998f] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Treatment of [UIV(N3)(TrenTIPS)] (1, TrenTIPS = {N(CH2CH2NSiPri3)3}3-) with excess Li resulted in the isolation of [{UIV(μ-NLi2)(TrenTIPS)}2] (2), which exhibits a diuranium(IV) 'diamond-core' dinitride motif. Over-reduction of 1 produces [UIII(TrenTIPS)] (3), and together with known [{UV(μ-NLi)(TrenTIPS)}2] (4) an overall reduction sequence 1 → 4 → 2 → 3 is proposed. Attempts to produce an odd-electron nitride from 2 resulted in the formation of [{UIV(TrenTIPS)}2(μ-NH)(μ-NLi2)Li] (5). Use of heavier alkali metals did not result in the formation of analogues of 2, emphasising the role of the high charge-to-radius-ratio of lithium stabilising the charge build up at the nitride. Variable-temperature magnetic data for 2 and 5 reveal large low-temperature magnetic moments, suggesting doubly degenerate ground states, where the effective symmetry of the strong crystal field of the nitride dominates over the spin-orbit coupled nature of the ground multiplet of uranium(IV). Spin Hamiltonian modelling of the magnetic data for 2 and 5 suggest U⋯U anti-ferromagnetic coupling of -4.1 and -3.4 cm-1, respectively. The nature of the U⋯U electronic communication was probed computationally, revealing a borderline case where the prospect of direct uranium-uranium bonding was raised, but in-depth computational analysis reveals that if any uranium-uranium bonding is present it is weak, and instead the nitride centres dominate the mediation of U⋯U electronic communication. This highlights the importance of obtaining high-level ab initio insight when probing potential actinide-actinide electronic communication and bonding in weakly coupled systems. The computational analysis highlights analogies between the 'diamond-core' dinitride of 2 and matrix-isolated binary U2N2.
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Affiliation(s)
- David M King
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Benjamin E Atkinson
- Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
| | - Lucile Chatelain
- Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
| | - Matthew Gregson
- Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
| | - John A Seed
- Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
| | - Ashley J Wooles
- Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
| | - Nikolas Kaltsoyannis
- Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
| | - Stephen T Liddle
- Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
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17
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Goodwin CAP, Janicke MT, Scott BL, Gaunt AJ. [AnI 3(THF) 4] (An = Np, Pu) Preparation Bypassing An 0 Metal Precursors: Access to Np 3+/Pu 3+ Nonaqueous and Organometallic Complexes. J Am Chem Soc 2021; 143:20680-20696. [PMID: 34854294 DOI: 10.1021/jacs.1c07967] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Direct comparison of homologous molecules provides a foundation from which to elucidate both subtle and patent changes in reactivity patterns, redox processes, and bonding properties across a series of elements. While trivalent molecular U chemistry is richly developed, analogous Np or Pu research has long been hindered by synthetic routes often requiring scarcely available metallic-phase source material, high-temperature solid-state reactions producing poorly soluble binary halides, or the use of pyrophoric reagents. The development of routes to nonaqueous Np3+/Pu3+ from widely available precursors can potentially transform the scope and pace of research into actinide periodicity. Here, aqueous stocks of An4+ (An = Np, Pu) are dehydrated to well-defined [AnCl4(DME)2] (DME = 1,2-dimethoxyethane), and then a single-step halide exchange/reduction employing Me3SiI produces [AnI3(THF)4] (THF = tetrahydrofuran) in a high to nearly quantitative crystalline yield (with I2 and Me3SiCl as easily removed byproducts). We demonstrate the synthetic utility of these An-iodide molecules, prepared by metal0-free routes, through characterization of archetypal complexes including the tris-silylamide, [Np{N(SiMe3)2}3], and bent metallocenes, [An(C5Me5)2(I)(THF)] (An = Np, Pu)─chosen because both motifs are ubiquitous in Th, U, and lanthanide research. The synthesis of [Np{N(Se═PPh2)2}3] is also reported, completing an isomorphous series that now extends from U to Am and is the first characterized Np3+-Se bond.
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Affiliation(s)
- Conrad A P Goodwin
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Michael T Janicke
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, 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
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18
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Staun SL, Wu G, Lukens WW, Hayton TW. Synthesis of a heterobimetallic actinide nitride and an analysis of its bonding. Chem Sci 2021; 12:15519-15527. [PMID: 35003580 PMCID: PMC8653994 DOI: 10.1039/d1sc05072a] [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: 09/13/2021] [Accepted: 11/13/2021] [Indexed: 11/21/2022] Open
Abstract
Reaction of [K(DME)][Th{N(R)(SiMe2 CH2)}2(NR2)] (R = SiMe3) with 1 equiv. of [U(NR2)3(NH2)] (1) in THF, in the presence of 18-crown-6, results in formation of a bridged uranium-thorium nitride complex, [K(18-crown-6)(THF)2][(NR2)3UIV(μ-N)ThIV(NR2)3] (2), which can be isolated in 48% yield after work-up. Complex 2 is the first isolable molecular mixed-actinide nitride complex. Also formed in the reaction is the methylene-bridged mixed-actinide nitride, [K(18-crown-6)][K(18-crown-6)(Et2O)2][(NR2)2U(μ-N)(μ-κ2-C,N-CH2SiMe2NR)Th(NR2)2]2 (3), which can be isolated in 34% yield after work-up. Complex 3 is likely generated by deprotonation of a methyl group in 2 by [NR2]-, yielding the new μ-CH2 moiety and HNR2. Reaction of 2 with 0.5 equiv. of I2 results in formation of a UV/ThIV bridged nitride, [(NR2)3UV(μ-N)ThIV(NR2)3] (4), which can be isolated in 42% yield after work-up. The electronic structure of 4 was analyzed with EPR spectroscopy, SQUID magnetometry, and NIR-visible spectroscopy. This analysis demonstrated that the energies of 5f orbitals of 4 are largely determined by the strong ligand field exerted by the nitride ligand.
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Affiliation(s)
- Selena L Staun
- Department of Chemistry and Biochemistry, University of California, Santa Barbara Santa Barbara California 93106 USA
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara Santa Barbara California 93106 USA
| | - Wayne W Lukens
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley California 94720 USA
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara Santa Barbara California 93106 USA
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19
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Yu X, Sergentu DC, Feng R, Autschbach J. Covalency of Trivalent Actinide Ions with Different Donor Ligands: Do Density Functional and Multiconfigurational Wavefunction Calculations Corroborate the Observed "Breaks"? Inorg Chem 2021; 60:17744-17757. [PMID: 34747167 DOI: 10.1021/acs.inorgchem.1c02374] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
A comprehensive ab initio study of periodic actinide-ligand bonding trends for trivalent actinides is performed. Relativistic density functional theory (DFT) and complete active-space (CAS) self-consistent field wavefunction calculations are used to dissect the chemical bonding in the [AnCl6]3-, [An(CN)6]3-, [An(NCS)6]3-, [An(S2PMe2)3], [An(DPA)3]3-, and [An(HOPO)]- series of actinide (An = U-Es) complexes. Except for some differences for the early actinide complexes with DPA, bond orders and excess 5f-shell populations from donation bonding show qualitatively similar trends in 5f n active-space CAS vs DFT calculations. The influence of spin-orbit coupling on donation bonding is small for the tested systems. Along the actinide series, chemically soft vs chemically harder ligands exhibit clear differences in bonding trends. There are pronounced changes in the 5f populations when moving from Pu to Am or Cm, which correlate with previously noted "breaks" in chemical trends. Bonding involving 5f becomes very weak beyond Cm/Bk. We propose that Cm(III) is a borderline case among the trivalent actinides that can be meaningfully considered to be involved in ground-state 5f covalent bonding.
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Affiliation(s)
- Xiaojuan Yu
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, United States
| | - Dumitru-Claudiu Sergentu
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, United States
| | - Rulin Feng
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, United States
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, United States
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20
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Kent GT, Yu X, Wu G, Autschbach J, Hayton TW. Synthesis and electronic structure analysis of the actinide allenylidenes, [{(NR 2) 3}An(CCCPh 2)] - (An = U, Th; R = SiMe 3). Chem Sci 2021; 12:14383-14388. [PMID: 34880989 PMCID: PMC8580070 DOI: 10.1039/d1sc04666g] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 10/02/2021] [Indexed: 11/26/2022] Open
Abstract
The reaction of [AnCl(NR2)3] (An = U, Th, R = SiMe3) with in situ generated lithium-3,3-diphenylcyclopropene results in the formation of [{(NR2)3}An(CH[double bond, length as m-dash]C[double bond, length as m-dash]CPh2)] (An = U, 1; Th, 2) in good yields after work-up. Deprotonation of 1 or 2 with LDA/2.2.2-cryptand results in formation of the anionic allenylidenes, [Li(2.2.2-cryptand)][{(NR2)3}An(CCCPh2)] (An = U, 3; Th, 4). The calculated 13C NMR chemical shifts of the Cα, Cβ, and Cγ nuclei in 2 and 4 nicely reproduce the experimentally assigned order, and exhibit a characteristic spin-orbit induced downfield shift at Cα due to involvement of the 5f orbitals in the Th-C bonds. Additionally, the bonding analyses for 3 and 4 show a delocalized multi-center character of the ligand π orbitals involving the actinide. While a single-triple-single-bond resonance structure (e.g., An-C[triple bond, length as m-dash]C-CPh2) predominates, the An[double bond, length as m-dash]C[double bond, length as m-dash]C[double bond, length as m-dash]CPh2 resonance form contributes, as well, more so for 3 than for 4.
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Affiliation(s)
- Greggory T Kent
- Department of Chemistry and Biochemistry, University of California Santa Barbara Santa Barbara CA 93106 USA
| | - Xiaojuan Yu
- Department of Chemistry, University at Buffalo, State University of New York Buffalo NY 14260 USA
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara Santa Barbara CA 93106 USA
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, State University of New York Buffalo NY 14260 USA
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara Santa Barbara CA 93106 USA
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21
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Kent GT, Yu X, Pauly C, Wu G, Autschbach J, Hayton TW. Synthesis of Parent Acetylide and Dicarbide Complexes of Thorium and Uranium and an Examination of Their Electronic Structures. Inorg Chem 2021; 60:15413-15420. [PMID: 34585570 DOI: 10.1021/acs.inorgchem.1c02064] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The reaction of [AnCl(NR2)3] (An = U or Th; R = SiMe3) with NaCCH and tetramethylethylenediamine (TMEDA) results in the formation of [An(C≡CH)(NR2)3] (1, An = U; 2, An = Th), which can be isolated in good yields after workup. Similarly, the reaction of 3 equiv of NaCCH and TMEDA with [AnCl(NR2)3] results in the formation of [Na(TMEDA)][An(C≡CH)2(NR2)3] (4, An = U; 5, An = Th), which can be isolated in fair yields after workup. The reaction of 1 with 2 equiv of KC8 and 1 equiv of 2.2.2-cryptand in tetrahydrofuran results in formation of the uranium(III) acetylide complex [K(2.2.2-cryptand)][U(C≡CH)(NR2)3] (3). Thermolysis of 1 or 2 results in formation of the bimetallic dicarbide complexes [{An(NR2)3}2(μ,η1:η1-C2)] (6, An = U; 7, An = Th), whereas the reaction of 1 with [Th{N(R)(SiMe2CH2)}(NR2)2] results in the formation of [U(NR2)3(μ,η1:η1-C2)Th(NR2)3] (8). The 13C NMR chemical shifts of the α-acetylide carbon atoms in 2, 5, and 7 exhibit a characteristic spin-orbit-induced downfield shift, due to participation of the 5f orbitals in the Th-C bonds. Magnetism measurements demonstrate that 6 displays weak ferromagnetic coupling between the uranium(IV) centers (J = 1.78 cm-1).
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Affiliation(s)
- Greggory T Kent
- 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
| | - Christophe Pauly
- Organisch-Chemisches Institut, University of Münster, Corrensstraße 40, Münster 48149, Germany
| | - 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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Du J, Seed JA, Berryman VEJ, Kaltsoyannis N, Adams RW, Lee D, Liddle ST. Exceptional uranium(VI)-nitride triple bond covalency from 15N nuclear magnetic resonance spectroscopy and quantum chemical analysis. Nat Commun 2021; 12:5649. [PMID: 34561448 PMCID: PMC8463702 DOI: 10.1038/s41467-021-25863-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 09/06/2021] [Indexed: 11/24/2022] Open
Abstract
Determining the nature and extent of covalency of early actinide chemical bonding is a fundamentally important challenge. Recently, X-ray absorption, electron paramagnetic, and nuclear magnetic resonance spectroscopic studies have probed actinide-ligand covalency, largely confirming the paradigm of early actinide bonding varying from ionic to polarised-covalent, with this range sitting on the continuum between ionic lanthanide and more covalent d transition metal analogues. Here, we report measurement of the covalency of a terminal uranium(VI)-nitride by 15N nuclear magnetic resonance spectroscopy, and find an exceptional nitride chemical shift and chemical shift anisotropy. This redefines the 15N nuclear magnetic resonance spectroscopy parameter space, and experimentally confirms a prior computational prediction that the uranium(VI)-nitride triple bond is not only highly covalent, but, more so than d transition metal analogues. These results enable construction of general, predictive metal-ligand 15N chemical shift-bond order correlations, and reframe our understanding of actinide chemical bonding to guide future studies.
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Affiliation(s)
- Jingzhen Du
- 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
| | - Victoria E J Berryman
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Nikolas Kaltsoyannis
- 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 and Analytical Science, The University of Manchester, Manchester, M13 9PL, UK.
| | - Stephen T Liddle
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
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23
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Tsantis ST, Danelli P, Tzimopoulos DI, Raptopoulou CP, Psycharis V, Perlepes SP. Pentanuclear Thorium(IV) Coordination Cluster from the Use of Di(2-pyridyl) Ketone. Inorg Chem 2021; 60:11888-11892. [PMID: 34351755 DOI: 10.1021/acs.inorgchem.1c01800] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Th(NO3)4·5H2O/di(2-pyridyl) ketone [(py)2CO] reaction system gives a pentanuclear cluster containing the doubly deprotonated form of the gem-diol derivative of the ligand. The cluster consists of a tetrahedral arrangement of four ThIV ions centered on the fifth ion, which is the first characterized ThIV5 complex. The analysis of its structure reveals that this is a Kuratowski-type coordination compound.
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Affiliation(s)
- Sokratis T Tsantis
- Department of Chemistry, University of Patras, 26504 Patras, Greece.,Foundation for Research and Technology-Hellas (FORTH), Institute of Chemical Engineering Sciences (ICE-HT), P.O Box 144, 26504 Platani, Greece
| | | | | | - Catherine P Raptopoulou
- Institute of Nanoscience and Nanotechnology NCSR "Demokritos", 15310 Aghia Paraskevi, Attikis, Greece
| | - Vassilis Psycharis
- Institute of Nanoscience and Nanotechnology NCSR "Demokritos", 15310 Aghia Paraskevi, Attikis, Greece
| | - Spyros P Perlepes
- Department of Chemistry, University of Patras, 26504 Patras, Greece.,Foundation for Research and Technology-Hellas (FORTH), Institute of Chemical Engineering Sciences (ICE-HT), P.O Box 144, 26504 Platani, Greece
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24
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Réant BLL, Berryman VEJ, Basford AR, Nodaraki LE, Wooles AJ, Tuna F, Kaltsoyannis N, Mills DP, Liddle ST. 29Si NMR Spectroscopy as a Probe of s- and f-Block Metal(II)-Silanide Bond Covalency. J Am Chem Soc 2021; 143:9813-9824. [PMID: 34169713 DOI: 10.1021/jacs.1c03236] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the use of 29Si NMR spectroscopy and DFT calculations combined to benchmark the covalency in the chemical bonding of s- and f-block metal-silicon bonds. The complexes [M(SitBu3)2(THF)2(THF)x] (1-M: M = Mg, Ca, Yb, x = 0; M = Sm, Eu, x = 1) and [M(SitBu2Me)2(THF)2(THF)x] (2-M: M = Mg, x = 0; M = Ca, Sm, Eu, Yb, x = 1) have been synthesized and characterized. DFT calculations and 29Si NMR spectroscopic analyses of 1-M and 2-M (M = Mg, Ca, Yb, No, the last in silico due to experimental unavailability) together with known {Si(SiMe3)3}--, {Si(SiMe2H)3}--, and {SiPh3}--substituted analogues provide 20 representative examples spanning five silanide ligands and four divalent metals, revealing that the metal-bound 29Si NMR isotropic chemical shifts, δSi, span a wide (∼225 ppm) range when the metal is kept constant, and direct, linear correlations are found between δSi and computed delocalization indices and quantum chemical topology interatomic exchange-correlation energies that are measures of bond covalency. The calculations reveal dominant s- and d-orbital character in the bonding of these silanide complexes, with no significant f-orbital contributions. The δSi is determined, relatively, by paramagnetic shielding for a given metal when the silanide is varied but by the spin-orbit shielding term when the metal is varied for a given ligand. The calculations suggest a covalency ordering of No(II) > Yb(II) > Ca(II) ≈ Mg(II), challenging the traditional view of late actinide chemical bonding being equivalent to that of the late lanthanides.
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Affiliation(s)
- Benjamin L L Réant
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Victoria E J Berryman
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Annabel R Basford
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Lydia E Nodaraki
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Ashley J Wooles
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Floriana Tuna
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Nikolas Kaltsoyannis
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - David P Mills
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Stephen T Liddle
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
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25
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Walter ED, Capan C, Casella AJ, Carter JC, McNamara BK, Soderquist CZ, Sinkov SI, Clark RA, Heller FD, Sweet LE, Corbey JF, Cho H. Measurement of local magnetic fields in actinide tetrafluorides. J Chem Phys 2021; 154:211101. [PMID: 34240987 DOI: 10.1063/5.0052323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Fluorine-19 magnetic shielding tensors have been measured in a series of actinide tetrafluorides (AnF4) by solid state nuclear magnetic resonance spectroscopy. Tetravalent actinide centers with 0-8 valence electrons can form tetrafluorides with the same monoclinic structure type, making these compounds an attractive choice for a systematic study of the variation in the electronic structure across the 5f row of the Periodic Table. Pronounced deviations from predictions based on localized valence electron models have been detected by these experiments, which suggests that this approach may be used as a quantitative probe of electronic correlations.
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Affiliation(s)
- Eric D Walter
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99354, USA
| | - Cigdem Capan
- Department of Physics, Washington State University Tri-Cities, Richland, Washington 99352, USA
| | - Amanda J Casella
- Energy and Environment Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99354, USA
| | - Jennifer C Carter
- Energy and Environment Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99354, USA
| | - Bruce K McNamara
- Energy and Environment Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99354, USA
| | - Chuck Z Soderquist
- Energy and Environment Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99354, USA
| | - Sergey I Sinkov
- Energy and Environment Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99354, USA
| | - Richard A Clark
- Energy and Environment Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99354, USA
| | - Forrest D Heller
- Energy and Environment Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99354, USA
| | - Lucas E Sweet
- National Security Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99354, USA
| | - Jordan F Corbey
- National Security Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99354, USA
| | - Herman Cho
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99354, USA
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26
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Gordon CP, Lätsch L, Copéret C. Nuclear Magnetic Resonance: A Spectroscopic Probe to Understand the Electronic Structure and Reactivity of Molecules and Materials. J Phys Chem Lett 2021; 12:2072-2085. [PMID: 33617260 DOI: 10.1021/acs.jpclett.0c03520] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
This Perspective focuses on the ability of chemical shift to identify and characterize the electronic structure and associated reactivity of molecules and materials. After a general introduction on NMR parameters, we will show selected examples where the chemical shift of various NMR active nuclei has been used to investigate and understand electronic properties, with a particular focus on organometallic compounds and inorganic materials with relevance to catalysis. We will demonstrate how the NMR parameter of probe molecules and ligands can be used to elucidate the nature of active sites and how they can help to understand and predict their reactivity. Lastly, we will give an overview over recent advances in deciphering metal NMR parameters. Overall, we show how chemical shift is a reactivity descriptor that can be analyzed and understood on a molecular level.
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Affiliation(s)
- Christopher P Gordon
- ETH Zurich, Department of Chemistry and Applied Biosciences, Vladimir-Prelog-Weg 2, Zurich, Switzerland
| | - Lukas Lätsch
- ETH Zurich, Department of Chemistry and Applied Biosciences, Vladimir-Prelog-Weg 2, Zurich, Switzerland
| | - Christophe Copéret
- ETH Zurich, Department of Chemistry and Applied Biosciences, Vladimir-Prelog-Weg 2, Zurich, Switzerland
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