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Tarlton M, Carpenter SH, Tondreau AM. Alkyl Coordination in meso-(ONO) 2- Supported Uranium(IV) Complexes. Organometallics 2024; 43:1329-1333. [PMID: 38938898 PMCID: PMC11203667 DOI: 10.1021/acs.organomet.4c00069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 04/25/2024] [Accepted: 05/10/2024] [Indexed: 06/29/2024]
Abstract
A series of U(IV) complexes bearing alkyl and chloride ligands in the trans configuration was synthesized and characterized. Starting with the diastereopure U(IV) trans-dichloride complex meso-( tBu2PONO)UCl2(dtbpy) (1, tBu2PONO = 2,6-bis((di-tert-butylphosphino)methanolato)pyridine), four distinct alkyl groups were employed to prepare ( tBu2PONO)U(R)Cl(dtbpy), where R = (trimethylsilyl)methyl (neosilyl), 2a, R = 2,2-dimethyl propyl (neopentyl), 2b, and R = 2-methyl-2-phenyl propyl (neophyl), 2c. Alkylation occurs with specificity but generates a predominant species and a minor species corresponding to anti/syn regioisomers relative to the tBu2P groups of the ligand. For synthesis using R = methyl, the dimethyl complex ( tBu2PONO)U(Me)2(dtbpy), 2d, was prepared; the addition of 1 equiv of MeLi produced a mixture of products. Complexes 2a-2d were characterized using single crystal X-ray diffraction (SC-XRD), UV-vis-nIR, and 1H and 31P NMR spectroscopies.
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Affiliation(s)
- Michael
L. Tarlton
- Los Alamos National Laboratory, Los Alamos, New Mexico 87544, United States
| | | | - Aaron M. Tondreau
- Los Alamos National Laboratory, Los Alamos, New Mexico 87544, United States
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Samuvel Michael D, Schreckenbach G. Bis(acyl)phosphide Complexes of U(III)/U(IV): A Case of a Hidden Redox-Active Ligand. Inorg Chem 2024; 63:9711-9714. [PMID: 38749025 DOI: 10.1021/acs.inorgchem.4c00940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2024]
Abstract
The recently reported tris(bis(2,4,6-triisopropylbenzoyl)-phosphide)uranium (UIII(trippBAP)3, 2) complex (Inorg. Chem. 2022, 61 (32), 12508-12517) demonstrated a silent 31P NMR spectrum. This complex was described as a U(III) complex with an organic radical ligand fragment. Moreover, the EPR spectrum of 2 was indicative of an organic radical in the ligand framework complexed to uranium, in contrast to that of UIV(mesBAP)4, 1. Herein, with the help of relativistic density functional theory (DFT) calculations, the electronic structures of 1, 2, and U(mesBAP)3 (4) are examined in an effort to understand the unusual 31P NMR spectrum of 2. Results indicate the reduction of the carbonyl bonds and delocalization of the electrons over the ligands, indicative of U → L backbonding. Additionally, the reduced acyl carbons are found to exist as ketyl radicals [O═C• -] that are responsible for the silent 31P NMR spectra of 2. These findings demonstrate the redox noninnocent nature of BAP- in 2 and 4, causing uranium to exist in a formal oxidation state of +4.
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Affiliation(s)
- David Samuvel Michael
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada, R3T 2N2
| | - Georg Schreckenbach
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada, R3T 2N2
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3
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Carpenter SH, Mengell J, Chen J, Jones MR, Kirk ML, Tondreau AM. Determining the Effects of Zero-Field Splitting and Magnetic Exchange in Dimeric Europium(II) Complexes. Inorg Chem 2024; 63:8516-8520. [PMID: 38667056 DOI: 10.1021/acs.inorgchem.4c00694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2024]
Abstract
Related BAP [BAP = bis(acyl)phosphide] and Acac (Acac = β-diketonate) molecules perform as robust supports for both lanthanide and actinide metals. Here, a molecular bimetallic Eu2+ complex was successfully targeted and isolated by employing sodium bis(mesitoyl)phosphide [Na(mesBAP)] in a salt metathesis with EuI2, producing [Eu(mesBAP)2(et2o)]2 (et2o = metal-coordinated diethyl ether). The corresponding Acac-Eu2+ complex was targeted using mesAcac- (1,3-dimesityl-1,3-propanedione), generating [Eu(mesAcac)2(et2o)]2. Both complexes were characterized by single-crystal X-ray diffraction, UV-vis, IR, and NMR spectroscopies, and variable-temperature magnetic susceptibility. [Eu(mesBAP)2(et2o)]2 was persistent under anaerobic, anhydrous conditions, whereas the analogous [Eu(mesAcac)2(et2o)]2 showed evidence of decomposition under identical conditions. Variable-temperature magnetic susceptibility and magnetization studies of [Eu(mesBAP)2(et2o)]2 and [Eu(mesAcac)2(et2o)]2 were performed, resulting in similar magnetic exchange coupling values of Jex = -0.018 and -0.023 cm-1 and axial zero-field-splitting D values of -0.38 and -0.51 cm-1, respectively.
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Affiliation(s)
- Stephanie H Carpenter
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Joshua Mengell
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Ju Chen
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Margaret R Jones
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Martin L Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, New Mexico 87131, United States
- The Center for High Technology Materials, The University of New Mexico, Albuquerque, New Mexico 87106, United States
- The Center for Quantum Information and Control, The University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Aaron M Tondreau
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
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Wedal JC, Moore WNG, Lukens WW, Evans WJ. Perplexing EPR Signals from 5f 36d 1 U(II) Complexes. Inorg Chem 2024; 63:2945-2953. [PMID: 38279200 DOI: 10.1021/acs.inorgchem.3c03449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2024]
Abstract
Metal complexes with unpaired electrons in orbitals of different angular momentum quantum numbers (e.g., f and d orbitals) are unusual and opportunities to study the interactions among these electrons are rare. X-band electron paramagnetic resonance (EPR) data were collected at <10 and 77 K on 10 U(II) complexes with 5f36d1 electron configurations and on some analogous Ce(II), Pr(II), and Nd(II) complexes with 4fn5d1 electron configurations. The U(II) compounds unexpectedly display similar two-line axial signals with g|| = 2.04 and g⊥ = 2.00 at 77 K. In contrast, U(II) complexes with 5f4 configurations are EPR-silent. Unlike U(II), the congenic 4f35d1 Nd(II) complex is EPR-silent. The Ce(II) complex with a 4f15d1 configuration is also EPR-silent, but a signal is observed for the Pr(II) complex, which has a 4f25d1 configuration. Whether or not an EPR signal is expected for these complexes depends on the coupling between f and d electrons. Since the coupling in U(II) systems is expected to be sufficiently strong to preclude an EPR signal from compounds with a 5f36d1 configuration, the results are viewed as unexplained phenomena. However, they do show that 5f36d1 U(II) samples can be differentiated from 5f4 U(II) complexes by EPR spectroscopy.
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Affiliation(s)
- Justin C Wedal
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
| | - William N G Moore
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
| | - Wayne W Lukens
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - William J Evans
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
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Widera A, Conti R, Schrader E, Aebli M, Wörle M, Grützmacher H. Bis(acyl)phosphide - Ambidentate Ligands for the Synthesis of Group 14 and 15 Main Group Element Compounds. Chempluschem 2023; 88:e202200451. [PMID: 36786446 DOI: 10.1002/cplu.202200451] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 02/12/2023] [Accepted: 02/13/2023] [Indexed: 02/15/2023]
Abstract
The reactivity of the bis(acyl)phosphide ion [P(COR)2 ]- (BAP- , R=Ph, Mes) with silicon halides SiX4 (X=Cl, Br) and pnictogen chlorides ECl3 (E=As, Sb and Bi) was investigated. The reaction with SiX4 leads to the hexacoordinate silanes SiX2 (BAP)2 in which BAP- is coordinated in the chelating κ2 -O,O' mode, analogously to acac- . Unexpectedly, the coordination behaviour of BAP- differs from the one of acac- in the interpnictogen compounds E(BAP)3 (E=As, Sb) in which the formation of E-P bonds is favoured over κ2 -O,O' chelation via the oxygen centres. Finally, the reaction of BiCl3 with three equivalents of Na(BAP) leads to the formation of red, crystalline Bi2 (BAP)4 , an air stable dibismuthine, as product of a redox reaction.
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Affiliation(s)
- Anna Widera
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5/10, 8093, Zürich, Switzerland
| | - Riccardo Conti
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5/10, 8093, Zürich, Switzerland.,Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität, Egerlandstraße 1, 91058, Erlangen, Germany
| | - Erik Schrader
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5/10, 8093, Zürich, Switzerland
| | - Marcel Aebli
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5/10, 8093, Zürich, Switzerland
| | - Michael Wörle
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5/10, 8093, Zürich, Switzerland
| | - Hansjörg Grützmacher
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5/10, 8093, Zürich, Switzerland
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Chen J, Carpenter SH, Fetrow TV, Mengell J, Kirk ML, Tondreau AM. Magnetism Studies of Bis(acyl)phosphide-Supported Eu 3+ and Eu 2+ Complexes. Inorg Chem 2022; 61:18466-18475. [DOI: 10.1021/acs.inorgchem.2c02675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Ju Chen
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, New Mexico87131, United States
| | | | - Taylor V. Fetrow
- Los Alamos National Laboratory, Los Alamos, New Mexico87545, United States
| | - Joshua Mengell
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, New Mexico87131, United States
| | - Martin L. Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, New Mexico87131, United States
- The Center for High Technology Materials, The University of New Mexico, Albuquerque, New Mexico87106, United States
- The Center for Quantum Information and Control (CQuIC), The University of New Mexico, Albuquerque, New Mexico87131, United States
| | - Aaron M. Tondreau
- Los Alamos National Laboratory, Los Alamos, New Mexico87545, United States
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