1
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Gupta H, Vincenzini BD, Bacon AM, Schelter EJ. Assembly of a trapped valent Ce III/IV-TCNQ complex through metal-ligand redox cooperativity. Chem Commun (Camb) 2024; 60:6909-6912. [PMID: 38881335 DOI: 10.1039/d4cc01478b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2024]
Abstract
Complex (Cp3CeIV)2(TCNQ)(CeIIICp3)2 (1) was prepared by reducing neutral TCNQ0 (tetracyanoquinodimethane) with Cp3Ce(THF). Two types of cerium centres with a dianionic TCNQ2- moiety are present in 1, wherein each of the four cyano-groups are bound by a cation. Formation of this trapped-valent organocerium compound 1 is facilitated by metal-ligand redox cooperativity. Characterization of 1 was carried out using structural-, magnetometry-, and IR-spectroscopic analyses. Photophysical studies on this compound reveal CeIII luminescence, and opens up avenues for promising multifunctional, mixed-valent lanthanide materials.
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Affiliation(s)
- Himanshu Gupta
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, USA.
| | - Brett D Vincenzini
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, USA.
| | - Alexandra M Bacon
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, USA.
| | - Eric J Schelter
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, USA.
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2
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Gremillion AJ, Ross J, Yu X, Ishtaweera P, Anwander R, Autschbach J, Baker GA, Kelley SP, Walensky JR. Facile Oxidation of Ce(III) to Ce(IV) Using Cu(I) Salts. Inorg Chem 2024; 63:9602-9609. [PMID: 38507258 DOI: 10.1021/acs.inorgchem.3c04337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2024]
Abstract
The synthesis, luminescence, and electrochemical properties of the Ce(III) compound, [(C5Me5)2(2,6-iPr2C6H3O)Ce(THF)], 1, were investigated. Based on the electrochemical data, treatment of 1 with CuX (X = Cl, Br, I) results in the formation of the corresponding Ce(IV) complexes, [(C5Me5)2(2,6-iPr2C6H3O)Ce(X)]. Each complex has been characterized using NMR, IR, and UV-vis spectroscopy as well as structurally determined using X-ray crystallography. Additionally, the treatment of [(C5Me5)2(2,6-iPr2C6H3O)Ce(Br)] with AgF results in the formation of the putative [(C5Me5)2(2,6-iPr2C6H3O)Ce(F)]. The electronic structure of these Ce(IV)-X complexes was investigated by bond analyses and the Ce(IV)-F moiety using quantum chemistry NMR calculations.
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Affiliation(s)
- Alexander J Gremillion
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Jason Ross
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Xiaojuan Yu
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, United States
| | - Piyuni Ishtaweera
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Reiner Anwander
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, 72076 Tübingen, Germany
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, United States
| | - Gary A Baker
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Steven P Kelley
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Justin R Walensky
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
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3
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Boggiano A, Bernbeck MG, Jiang N, La Pierre HS. Coordination Modes and Binding Patterns in Lanthanum Phosphoramide Complexes. Inorg Chem 2024; 63:9638-9647. [PMID: 38446786 PMCID: PMC11134493 DOI: 10.1021/acs.inorgchem.3c04521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 02/16/2024] [Accepted: 02/21/2024] [Indexed: 03/08/2024]
Abstract
A monoanionic phosphoramide ligand is introduced, which forms a series of lanthanum complexes with the ligand in both anionic and neutral forms. Stoichiometric control alone provides monometallic complexes with either two or three phosphoramide ligands. Alternatively, a combination of anionic and neutral proteo ligands featuring intramolecular hydrogen bonding can be obtained. The anionic form of the ligand binds lanthanum as a bi- or monodentate ligand, depending on the steric demand at the metal center, while the protonated ligand binds exclusively through the phosphoramide oxygen donor.
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Affiliation(s)
- Andrew
C. Boggiano
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332-0400, United States
| | - Maximilian G. Bernbeck
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332-0400, United States
| | - Ningxin Jiang
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332-0400, United States
| | - Henry S. La Pierre
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332-0400, United States
- Nuclear
and Radiological Engineering and Medical Physics Program, School of
Mechanical Engineering, Georgia Institute
of Technology, Atlanta, Georgia 30332-0400, United States
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4
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Tateyama H, Boggiano AC, Liao C, Otte KS, Li X, La Pierre HS. Tetravalent Cerium Alkyl and Benzyl Complexes. J Am Chem Soc 2024; 146:10268-10273. [PMID: 38564671 PMCID: PMC11027143 DOI: 10.1021/jacs.4c01964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 03/22/2024] [Accepted: 03/25/2024] [Indexed: 04/04/2024]
Abstract
High-valent cerium complexes of alkyl and benzyl ligands are unprecedented due to the incompatibility of the typically highly oxidizing Ce4+ ion and the reducing alkyl or benzyl ligand. Herein we report the synthesis and isolation of the first tetravalent cerium alkyl and benzyl complexes supported by the tri-tert-butyl imidophosphorane ligand, [NP(tBu)3]1-. The Ce4+ monoiodide complex, [Ce4+I(NP(tert-butyl)3)3] (1-CeI), serves as a precursor to the alkyl and benzyl complexes, [Ce4+(Npt)(NP(tert-butyl)3)3] (2-CeNpt) (Npt = neopentyl, CH2C(CH3)3) and [Ce4+(Bn)(NP(tert-butyl)3)3] (2-CeBn) (Bn = benzyl, CH2Ph). The bonding and structure of these complexes are characterized by single-crystal XRD, NMR and UV-vis-NIR spectroscopy, cyclic voltammetry, and DFT studies.
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Affiliation(s)
- Haruko Tateyama
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332-0400, United States
| | - Andrew C. Boggiano
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332-0400, United States
| | - Can Liao
- Department
of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Kaitlyn S. Otte
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332-0400, United States
| | - Xiaosong Li
- Department
of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Henry S. La Pierre
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332-0400, United States
- Nuclear
and Radiological Engineering and Medical Physics Program, School of
Mechanical Engineering, Georgia Institute
of Technology, Atlanta, Georgia 30332-0400, United States
- Physical
Sciences Division, Pacific Northwest National
Laboratory, Richland, Washington 99352, United States
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5
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Shafi Z, Gibson JK. Organolanthanide Complexes Containing Ln-CH 3 σ-bonds: Unexpectedly Similar Hydrolysis Rates for Trivalent and Tetravalent Organocerium. Inorg Chem 2023; 62:18399-18413. [PMID: 37910232 DOI: 10.1021/acs.inorgchem.3c02287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2023]
Abstract
We report the gas-phase preparation, isolation, and reactivity of a series of organolanthanides featuring the Ln-CH3 bond. The complexes are formed by decarboxylating anionic lanthanide acetates to form trivalent [LnIII(CH3)(CH3CO2)3]- (Ln = La, Ce, Pr, Nd, Sm, Tb, Tm, Yb, Lu), divalent [EuII(CH3)(CH3CO2)2]-, and the first examples of tetravalent organocerium complexes featuring CeIV-Calkyl σ-bonds: [CeIV(O)(CH3)(CH3CO2)2]- and [CeIV(O)(CH3)(NO3)2]-. Attempts to isolate PrIV-CH3 and TbIV-CH3 were unsuccessful; however, fragmentation patterns reveal that the oxidation of LnIII to a LnIV-oxo-acetate complex is more favorable for Ln = Pr than for Ln = Tb. The rate of Ln-CH3 hydrolysis is a measure of bond stability, and it decreases from LaIII-CH3 to LuIII-CH3, with increasing steric crowding for smaller Ln stabilizing the harder Ln-CH3 bond against hydrolysis. [EuII(CH3)(CH3CO2)2]- engages in a much faster hydrolysis versus LnIII-CH3. The surprising observation of similar hydrolysis rates for CeIV-CH3 and CeIII-CH3 is discussed with respect to sterics, the oxo ligand, and bond covalency in σ-bonded organolanthanides.
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Affiliation(s)
- Ziad Shafi
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - John K Gibson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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6
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Guo H, Hong D, Cui P. Tripodal tris(siloxide) ligand supported trivalent rare-earth metal complexes and redox reactivity. Dalton Trans 2023; 52:15672-15676. [PMID: 37882247 DOI: 10.1039/d3dt02519e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2023]
Abstract
Tripodal tris(siloxide) ligand supported rare-earth metal complexes LLn(III) (Ln = Ce, Pr, Tb, Y, Lu) were synthesized. The Ce(III) complex was oxidized with [N(C6H4Br)3][SbCl6] to a Ce(IV) chloride complex, which reacted with tBuONa to form a Ce(IV) tert-butoxide complex, one displaying a reduction potential cathodically shifted relative to that of Ce(IV) chloride complex.
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Affiliation(s)
- Hui Guo
- Key Laboratory of Functional Molecular Solids, Ministry of Education; Anhui Laboratory of Molecule-Based Materials; College of Chemistry and Materials Science; Anhui Normal University, S 189, Jiuhua Road, Wuhu, Anhui 241002, P. R. China.
| | - Dongjing Hong
- Key Laboratory of Functional Molecular Solids, Ministry of Education; Anhui Laboratory of Molecule-Based Materials; College of Chemistry and Materials Science; Anhui Normal University, S 189, Jiuhua Road, Wuhu, Anhui 241002, P. R. China.
| | - Peng Cui
- Key Laboratory of Functional Molecular Solids, Ministry of Education; Anhui Laboratory of Molecule-Based Materials; College of Chemistry and Materials Science; Anhui Normal University, S 189, Jiuhua Road, Wuhu, Anhui 241002, P. R. China.
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7
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Facile Solvent-Free Mechanochemical Synthesis of UI3 and Lanthanoid Iodides. CHEMISTRY 2022. [DOI: 10.3390/chemistry4040108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Lewis base-free lanthanoid (Ln) and actinoid (An) iodides are difficult to obtain, as standard protocols describe syntheses in solutions of donor solvents which are ultimately hard to remove. We have now established a mechanochemical approach towards the synthesis of Lewis base-free f-block metal iodides with excellent yields. In particular, we describe herein the synthesis of EuI2 as an example of a divalent lanthanoid iodide, of CeI3 as an example of a trivalent lanthanoid iodide, and of UI3 as the most important actinoid iodide. Each can be obtained in high yield with minimal work-up, presenting the most efficient and simple synthetic route to access these materials to date.
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8
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Kynman AE, Elghanayan LK, Desnoyer AN, Yang Y, Sévery L, Di Giuseppe A, Tilley TD, Maron L, Arnold PL. Controlled monodefluorination and alkylation of C(sp 3)-F bonds by lanthanide photocatalysts: importance of metal-ligand cooperativity. Chem Sci 2022; 13:14090-14100. [PMID: 36540817 PMCID: PMC9728647 DOI: 10.1039/d2sc04192h] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 11/05/2022] [Indexed: 08/01/2023] Open
Abstract
The controlled functionalization of a single fluorine in a CF3 group is difficult and rare. Photochemical C-F bond functionalization of the sp3-C-H bond in trifluorotoluene, PhCF3, is achieved using catalysts made from earth-abundant lanthanides, (CpMe4)2Ln(2-O-3,5- t Bu2-C6H2)(1-C{N(CH)2N(iPr)}) (Ln = La, Ce, Nd and Sm, CpMe4 = C5Me4H). The Ce complex is the most effective at mediating hydrodefluorination and defluoroalkylative coupling of PhCF3 with alkenes; addition of magnesium dialkyls enables catalytic C-F bond cleavage and C-C bond formation by all the complexes. Mechanistic experiments confirm the essential role of the Lewis acidic metal and support an inner-sphere mechanism of C-F activation. Computational studies agree that coordination of the C-F substrate is essential for C-F bond cleavage. The unexpected catalytic activity for all members is made possible by the light-absorbing ability of the redox non-innocent ligands. The results described herein underscore the importance of metal-ligand cooperativity, specifically the synergy between the metal and ligand in both light absorption and redox reactivity, in organometallic photocatalysis.
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Affiliation(s)
- Amy E Kynman
- Department of Chemistry, University of California, Berkeley Berkeley CA 94720-1460 USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley CA 94720 USA
| | - Luca K Elghanayan
- Department of Chemistry, University of California, Berkeley Berkeley CA 94720-1460 USA
| | - Addison N Desnoyer
- Department of Chemistry, University of California, Berkeley Berkeley CA 94720-1460 USA
| | - Yan Yang
- LPCNO, Université de Toulouse 135 Avenue de Rangueil 31077 Toulouse France
| | - Laurent Sévery
- Department of Chemistry, University of California, Berkeley Berkeley CA 94720-1460 USA
| | - Andrea Di Giuseppe
- Department of Chemistry, University of California, Berkeley Berkeley CA 94720-1460 USA
| | - T Don Tilley
- Department of Chemistry, University of California, Berkeley Berkeley CA 94720-1460 USA
| | - Laurent Maron
- LPCNO, Université de Toulouse 135 Avenue de Rangueil 31077 Toulouse France
| | - Polly L Arnold
- Department of Chemistry, University of California, Berkeley Berkeley CA 94720-1460 USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley CA 94720 USA
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9
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Pandey P, Yu X, Panetti GB, Lapsheva E, Gau MR, Carroll PJ, Autschbach J, Schelter EJ. Synthesis, Electrochemical, and Computational Studies of Organocerium(III) Complexes with Ce–Aryl Sigma Bonds. Organometallics 2022. [DOI: 10.1021/acs.organomet.2c00384] [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)
- Pragati Pandey
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34 Street, Philadelphia, Pennsylvania 19104, United States
| | - Xiaojuan Yu
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, United States
| | - Grace B. Panetti
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34 Street, Philadelphia, Pennsylvania 19104, United States
| | - Ekaterina Lapsheva
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34 Street, Philadelphia, Pennsylvania 19104, United States
| | - Michael R. Gau
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34 Street, Philadelphia, Pennsylvania 19104, United States
| | - Patrick J. Carroll
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34 Street, Philadelphia, Pennsylvania 19104, United States
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, United States
| | - Eric J. Schelter
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34 Street, Philadelphia, Pennsylvania 19104, United States
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10
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Neururer F, Liu S, Leitner D, Baltrun M, Fisher KR, Kopacka H, Wurst K, Daumann LJ, Munz D, Hohloch S. Mesoionic Carbenes in Low- to High-Valent Vanadium Chemistry. Inorg Chem 2021; 60:15421-15434. [PMID: 34590834 PMCID: PMC8527456 DOI: 10.1021/acs.inorgchem.1c02087] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Indexed: 12/12/2022]
Abstract
We report the synthesis of vanadium(V) oxo complex 1 with a pincer-type dianionic mesoionic carbene (MIC) ligand L1 and the general formula [VOCl(L1)]. A comparison of the structural (SC-XRD), electronic (UV-vis), and electrochemical (cyclic voltammetry) properties of 1 with the benzimidazolinylidene congener 2 (general formula [VOCl(L2)]) shows that the MIC is a stronger donor also for early transition metals with low d-electron population. Since electrochemical studies revealed both complexes to be reversibly reduced, the stronger donor character of MICs was not only demonstrated for the vanadium(V) but also for the vanadium(IV) oxidation state by isolating the reduced vanadium(IV) complexes [Co(Cp*)2][1] and [Co(Cp*)2][2] ([Co(Cp*)2] = decamethylcobaltocenium). The electronic structures of the compounds were investigated by computational methods. Complex 1 was found to be a moderate precursor for salt metathesis reactions, showing selective reactivity toward phenolates or secondary amides, but not toward primary amides and phosphides, thiophenols, or aryls/alkyls donors. Deoxygenation with electron-rich phosphines failed to give the desired vanadium(III) complex. However, treatment of the deprotonated ligand precursor with vanadium(III) trichloride resulted in the clean formation of the corresponding MIC vanadium(III) complex 6, which undergoes a clean two-electron oxidation with organic azides yielding the corresponding imido complexes. The reaction with TMS-N3 did not afford a nitrido complex, but instead the imido complex 10. This study reveals that, contrary to popular belief, MICs are capable of supporting early transition-metal complexes in a variety of oxidation states, thus making them promising candidates for the activation of small molecules and redox catalysis.
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Affiliation(s)
- Florian
R. Neururer
- Institute
of Inorganic, General and Theoretical Chemistry, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Shenyu Liu
- Faculty
of Science, Department of Chemistry, University
of Paderborn, Warburger Straße 100, 33098 Paderborn, Germany
| | - Daniel Leitner
- Institute
of Inorganic, General and Theoretical Chemistry, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Marc Baltrun
- Faculty
of Science, Department of Chemistry, University
of Paderborn, Warburger Straße 100, 33098 Paderborn, Germany
| | - Katherine R. Fisher
- Department
Chemie, Ludwigs-Maximilians-University Munich, Butenandtstraße 5-13 Haus D, 81377 Munich, Germany
| | - Holger Kopacka
- Institute
of Inorganic, General and Theoretical Chemistry, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Klaus Wurst
- Institute
of Inorganic, General and Theoretical Chemistry, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Lena J. Daumann
- Department
Chemie, Ludwigs-Maximilians-University Munich, Butenandtstraße 5-13 Haus D, 81377 Munich, Germany
| | - Dominik Munz
- Fakultät
NT, Inorganic Chemistry: Coordination Chemistry, Saarland University, Campus C4.1, 66123 Saarbrücken, Germany
| | - Stephan Hohloch
- Institute
of Inorganic, General and Theoretical Chemistry, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
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11
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Hirneise L, Langmann J, Zitzer G, Ude L, Maichle-Mössmer C, Scherer W, Speiser B, Anwander R. Tuning Organocerium Electrochemical Potentials by Extending Tris(cyclopentadienyl) Scaffolds with Terminal Halogenido, Siloxy, and Alkoxy Ligands. Organometallics 2021. [DOI: 10.1021/acs.organomet.1c00276] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Lars Hirneise
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Jan Langmann
- Institut für Physik, Universität Augsburg, Universitätsstraße 1, 86159 Augsburg, Germany
| | - Georg Zitzer
- Institut für Organische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Lukas Ude
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Cäcilia Maichle-Mössmer
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Wolfgang Scherer
- Institut für Physik, Universität Augsburg, Universitätsstraße 1, 86159 Augsburg, Germany
| | - Bernd Speiser
- Institut für Organische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Reiner Anwander
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
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12
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Panetti GB, Sergentu DC, Gau MR, Carroll PJ, Autschbach J, Walsh PJ, Schelter EJ. Isolation and characterization of a covalent Ce IV-Aryl complex with an anomalous 13C chemical shift. Nat Commun 2021; 12:1713. [PMID: 33731719 PMCID: PMC7969749 DOI: 10.1038/s41467-021-21766-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 02/02/2021] [Indexed: 12/13/2022] Open
Abstract
The synthesis of bona fide organometallic CeIV complexes is a formidable challenge given the typically oxidizing properties of the CeIV cation and reducing tendencies of carbanions. Herein, we report a pair of compounds comprising a CeIV - Caryl bond [Li(THF)4][CeIV(κ2-ortho-oxa)(MBP)2] (3-THF) and [Li(DME)3][CeIV(κ2-ortho-oxa)(MBP)2] (3-DME), ortho-oxa = dihydro-dimethyl-2-[4-(trifluoromethyl)phenyl]-oxazolide, MBP2- = 2,2'-methylenebis(6-tert-butyl-4-methylphenolate), which exhibit CeIV - Caryl bond lengths of 2.571(7) - 2.5806(19) Å and strongly-deshielded, CeIV - Cipso 13C{1H} NMR resonances at 255.6 ppm. Computational analyses reveal the Ce contribution to the CeIV - Caryl bond of 3-THF is ~12%, indicating appreciable metal-ligand covalency. Computations also reproduce the characteristic 13C{1H} resonance, and show a strong influence from spin-orbit coupling (SOC) effects on the chemical shift. The results demonstrate that SOC-driven deshielding is present for CeIV - Cipso 13C{1H} resonances and not just for diamagnetic actinide compounds.
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Affiliation(s)
- Grace B Panetti
- Roy and Diana Vagelos Laboratories Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Michael R Gau
- Roy and Diana Vagelos Laboratories Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA
| | - Patrick J Carroll
- Roy and Diana Vagelos Laboratories Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY, USA.
| | - Patrick J Walsh
- Roy and Diana Vagelos Laboratories Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA.
| | - Eric J Schelter
- Roy and Diana Vagelos Laboratories Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA.
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13
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Evans KJ, Morton PA, Sangster C, Mansell SM. One-step synthesis of heteroleptic rare-earth amide complexes featuring fluorenyl-tethered N-heterocyclic carbene ligands. Polyhedron 2021. [DOI: 10.1016/j.poly.2021.115021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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14
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Hay MA, Boskovic C. Lanthanoid Complexes as Molecular Materials: The Redox Approach. Chemistry 2021; 27:3608-3637. [PMID: 32965741 DOI: 10.1002/chem.202003761] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Indexed: 11/05/2022]
Abstract
The development of molecular materials with novel functionality offers promise for technological innovation. Switchable molecules that incorporate redox-active components are enticing candidate compounds due to their potential for electronic manipulation. Lanthanoid metals are most prevalent in their trivalent state and usually redox-activity in lanthanoid complexes is restricted to the ligand. The unique electronic and physical properties of lanthanoid ions have been exploited for various applications, including in magnetic and luminescent materials as well as in catalysis. Lanthanoid complexes are also promising for applications reliant on switchability, where the physical properties can be modulated by varying the oxidation state of a coordinated ligand. Lanthanoid-based redox activity is also possible, encompassing both divalent and tetravalent metal oxidation states. Thus, utilization of redox-active lanthanoid metals offers an attractive opportunity to further expand the capabilities of molecular materials. This review surveys both ligand and lanthanoid centered redox-activity in pre-existing molecular systems, including tuning of lanthanoid magnetic and photophysical properties by modulating the redox states of coordinated ligands. Ultimately the combination of redox-activity at both ligands and metal centers in the same molecule can afford novel electronic structures and physical properties, including multiconfigurational electronic states and valence tautomerism. Further targeted exploration of these features is clearly warranted, both to enhance understanding of the underlying fundamental chemistry, and for the generation of a potentially important new class of molecular material.
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Affiliation(s)
- Moya A Hay
- School of Chemistry, University of Melbourne, Victoria, 3010, Australia
| | - Colette Boskovic
- School of Chemistry, University of Melbourne, Victoria, 3010, Australia
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15
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Bayer U, Werner D, Berkefeld A, Maichle-Mössmer C, Anwander R. Cerium-quinone redox couples put under scrutiny. Chem Sci 2020; 12:1343-1351. [PMID: 34163897 PMCID: PMC8179043 DOI: 10.1039/d0sc04489j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Homoleptic cerous complexes Ce[N(SiMe3)2]3, [Ce{OSi(OtBu)3}3]2 and [Ce{OSiiPr3}3]2 were employed as thermally robust, weakly nucleophilic precursors to assess their reactivity towards 1,4-quinones in non-aqueous solution. The strongly oxidizing quinones 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) or tetrachloro-1,4-benzoquinone (Cl4BQ) readily form hydroquinolato-bridged ceric complexes of the composition [(CeIVL3)2(μ2-O2C6R4)]. Less oxidising quinones like 2,5-di-tert-butyl-1,4-benzoquinone (tBu2BQ) tend to engage in redox equilibria with the ceric hydroquinolato-bridged form being stable only in the solid state. Even less oxidising quinones such as tetramethyl-1,4-benzoquinone (Me4BQ) afford cerous semiquinolates of the type [(CeIIIL2(thf)2)(μ2-O2C6Me4)]2. All complexes were characterised by X-ray diffraction, 1H, 13C{1H} and 29Si NMR spectroscopy, DRIFT spectroscopy, UV-Vis spectroscopy and CV measurements. The species putatively formed during the electrochemical reduction of [CeIV{N(SiMe3)2}3]2(μ2-O2C6H4) could be mimicked by chemical reduction with CoIICp2 yielding [(CeIII{N(SiMe3)2}3)2(μ2-O2C6H4)][CoIIICp2]2.
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Affiliation(s)
- Uwe Bayer
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen (EKUT) Auf der Morgenstelle 18 72076 Tübingen Germany [http://uni-tuebingen.de/syncat-anwander]
| | - Daniel Werner
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen (EKUT) Auf der Morgenstelle 18 72076 Tübingen Germany [http://uni-tuebingen.de/syncat-anwander]
| | - Andreas Berkefeld
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen (EKUT) Auf der Morgenstelle 18 72076 Tübingen Germany [http://uni-tuebingen.de/syncat-anwander]
| | - Cäcilia Maichle-Mössmer
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen (EKUT) Auf der Morgenstelle 18 72076 Tübingen Germany [http://uni-tuebingen.de/syncat-anwander]
| | - Reiner Anwander
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen (EKUT) Auf der Morgenstelle 18 72076 Tübingen Germany [http://uni-tuebingen.de/syncat-anwander]
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16
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Arumugam S, Shankar B, Mondal KC. Redox Active Hexanuclear Mixed Valence Dicationic Ce(III)/Ce(IV) Coordination Clusters. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000659] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Selvakumar Arumugam
- Department of Chemistry Indian Institute of Technology Madras 600036 Chennai India
| | - Bhaskaran Shankar
- Department of Chemistry Indian Institute of Technology Madras 600036 Chennai India
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17
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Kent GT, Staun SL, Wu G, Hayton TW. Reactivity of [Ce(NR 2) 3] (R = SiMe 3) with Prospective Carbon Atom Transfer Reagents. Organometallics 2020. [DOI: 10.1021/acs.organomet.0c00186] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Greggory T. Kent
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Selena L. Staun
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, 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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18
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Smiles DE, Batista ER, Booth CH, Clark DL, Keith JM, Kozimor SA, Martin RL, Minasian SG, Shuh DK, Stieber SCE, Tyliszczak T. The duality of electron localization and covalency in lanthanide and actinide metallocenes. Chem Sci 2020; 11:2796-2809. [PMID: 34084340 PMCID: PMC8157540 DOI: 10.1039/c9sc06114b] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 02/04/2020] [Indexed: 12/14/2022] Open
Abstract
Previous magnetic, spectroscopic, and theoretical studies of cerocene, Ce(C8H8)2, have provided evidence for non-negligible 4f-electron density on Ce and implied that charge transfer from the ligands occurs as a result of covalent bonding. Strong correlations of the localized 4f-electrons to the delocalized ligand π-system result in emergence of Kondo-like behavior and other quantum chemical phenomena that are rarely observed in molecular systems. In this study, Ce(C8H8)2 is analyzed experimentally using carbon K-edge and cerium M5,4-edge X-ray absorption spectroscopies (XAS), and computationally using configuration interaction (CI) calculations and density functional theory (DFT) as well as time-dependent DFT (TDDFT). Both spectroscopic approaches provide strong evidence for ligand → metal electron transfer as a result of Ce 4f and 5d mixing with the occupied C 2p orbitals of the C8H8 2- ligands. Specifically, the Ce M5,4-edge XAS and CI calculations show that the contribution of the 4f1, or Ce3+, configuration to the ground state of Ce(C8H8)2 is similar to strongly correlated materials such as CeRh3 and significantly larger than observed for other formally Ce4+ compounds including CeO2 and CeCl6 2-. Pre-edge features in the experimental and TDDFT-simulated C K-edge XAS provide unequivocal evidence for C 2p and Ce 4f covalent orbital mixing in the δ-antibonding orbitals of e2u symmetry, which are the unoccupied counterparts to the occupied, ligand-based δ-bonding e2u orbitals. The C K-edge peak intensities, which can be compared directly to the C 2p and Ce 4f orbital mixing coefficients determined by DFT, show that covalency in Ce(C8H8)2 is comparable in magnitude to values reported previously for U(C8H8)2. An intuitive model is presented to show how similar covalent contributions to the ground state can have different impacts on the overall stability of f-element metallocenes.
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Affiliation(s)
- Danil E Smiles
- Lawrence Berkeley National Laboratory Berkeley California 94720 USA
| | | | - Corwin H Booth
- Lawrence Berkeley National Laboratory Berkeley California 94720 USA
| | - David L Clark
- Los Alamos National Laboratory Los Alamos New Mexico 87545 USA
| | | | - Stosh A Kozimor
- Los Alamos National Laboratory Los Alamos New Mexico 87545 USA
| | | | | | - David K Shuh
- Lawrence Berkeley National Laboratory Berkeley California 94720 USA
| | | | - Tolek Tyliszczak
- Lawrence Berkeley National Laboratory Berkeley California 94720 USA
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19
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Bayer U, Bock L, Maichle‐Mössmer C, Anwander R. A Facile Route toward Ceric Silylamide [Ce{N(SiHMe
2
)
2
}
4
]. Eur J Inorg Chem 2019. [DOI: 10.1002/ejic.201901023] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Uwe Bayer
- Institut für Anorganische Chemie University of Tübingen Auf der Morgenstelle 18 72076 Tübingen Germany
| | - Lorenz Bock
- Institut für Anorganische Chemie University of Tübingen Auf der Morgenstelle 18 72076 Tübingen Germany
| | - Cäcilia Maichle‐Mössmer
- Institut für Anorganische Chemie University of Tübingen Auf der Morgenstelle 18 72076 Tübingen Germany
| | - Reiner Anwander
- Institut für Anorganische Chemie University of Tübingen Auf der Morgenstelle 18 72076 Tübingen Germany
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20
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Baltrun M, Watt FA, Schoch R, Hohloch S. Dioxo-, Oxo-imido-, and Bis-imido-Molybdenum(VI) Complexes with a Bis-phenolate-NHC Ligand. Organometallics 2019. [DOI: 10.1021/acs.organomet.9b00472] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Marc Baltrun
- Paderborn University, Faculty of Science, Department of Chemistry, Warburger Straße 100, 33098 Paderborn, Germany
| | - Fabian A. Watt
- Paderborn University, Faculty of Science, Department of Chemistry, Warburger Straße 100, 33098 Paderborn, Germany
| | - Roland Schoch
- Paderborn University, Faculty of Science, Department of Chemistry, Warburger Straße 100, 33098 Paderborn, Germany
| | - Stephan Hohloch
- Paderborn University, Faculty of Science, Department of Chemistry, Warburger Straße 100, 33098 Paderborn, Germany
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21
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Palumbo CT, Zivkovic I, Scopelliti R, Mazzanti M. Molecular Complex of Tb in the +4 Oxidation State. J Am Chem Soc 2019; 141:9827-9831. [DOI: 10.1021/jacs.9b05337] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Chad T. Palumbo
- Insititut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Ivica Zivkovic
- Laboratory for Quantum Magnetism, Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Rosario Scopelliti
- Insititut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Marinella Mazzanti
- Insititut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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22
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Arnold PL, Kerr RWF, Weetman C, Docherty SR, Rieb J, Cruickshank FL, Wang K, Jandl C, McMullon MW, Pöthig A, Kühn FE, Smith AD. Selective and catalytic carbon dioxide and heteroallene activation mediated by cerium N-heterocyclic carbene complexes. Chem Sci 2018; 9:8035-8045. [PMID: 30568765 PMCID: PMC6262539 DOI: 10.1039/c8sc03312a] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 09/05/2018] [Indexed: 11/21/2022] Open
Abstract
A series of rare earth complexes of the form Ln(LR)3 supported by bidentate ortho-aryloxide-NHC ligands are reported (LR = 2-O-3,5-tBu2-C6H2(1-C{N(CH)2N(R)})); R = iPr, tBu, Mes; Ln = Ce, Sm, Eu). The cerium complexes cleanly and quantitatively insert carbon dioxide exclusively into all three cerium carbene bonds, forming Ce(LR·CO2)3. The insertion is reversible only for the mesityl-substituted complex Ce(LMes)3. Analysis of the capacity of Ce(LR)3 to insert a range of heteroallenes that are isoelectronic with CO2 reveals the solvent and ligand size dependence of the selectivity. This is important because only the complexes capable of reversible CO2-insertion are competent catalysts for catalytic conversions of CO2. Preliminary studies show that only Ce(LMes·CO2)3 catalyses the formation of propylene carbonate from propylene oxide under 1 atm of CO2 pressure. The mono-ligand complexes can be isolated from reactions using LiCe(NiPr2)4 as a starting material; LiBr adducts [Ce(LR)(NiPr2)Br·LiBr(THF)]2 (R = Me, iPr) are reported, along with a hexanuclear N-heterocyclic dicarbene [Li2Ce3(OArCMe-H)3(NiPr2)5(THF)2]2 by-product. The analogous para-aryloxide-NHC proligand (p-LMes = 4-O-2,6-tBu2-C6H2(1-C{N(CH)2NMes}))) has been made for comparison, but the rare earth tris-ligand complexes Ln(p-LMes)3(THF)2 (Ln = Y, Ce) are too reactive for straightforward Lewis pair separated chemistry to be usefully carried out.
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Affiliation(s)
- Polly L Arnold
- EaStCHEM School of Chemistry , University of Edinburgh , The King's Buildings , Edinburgh , EH9 3FJ , UK .
| | - Ryan W F Kerr
- EaStCHEM School of Chemistry , University of Edinburgh , The King's Buildings , Edinburgh , EH9 3FJ , UK . .,EaStCHEM School of Chemistry , University of St. Andrews , North Haugh, St. Andrews , KY16 9ST , UK, E-mail:
| | - Catherine Weetman
- EaStCHEM School of Chemistry , University of Edinburgh , The King's Buildings , Edinburgh , EH9 3FJ , UK .
| | - Scott R Docherty
- EaStCHEM School of Chemistry , University of Edinburgh , The King's Buildings , Edinburgh , EH9 3FJ , UK .
| | - Julia Rieb
- EaStCHEM School of Chemistry , University of Edinburgh , The King's Buildings , Edinburgh , EH9 3FJ , UK . .,Molecular Catalysis, Faculty of Chemistry and Catalysis Research Center , Technical University Munich , Lichtenbergstr. 4 , 85748 Garching bei München , Germany
| | - Faye L Cruickshank
- EaStCHEM School of Chemistry , University of Edinburgh , The King's Buildings , Edinburgh , EH9 3FJ , UK .
| | - Kai Wang
- EaStCHEM School of Chemistry , University of Edinburgh , The King's Buildings , Edinburgh , EH9 3FJ , UK .
| | - Christian Jandl
- EaStCHEM School of Chemistry , University of Edinburgh , The King's Buildings , Edinburgh , EH9 3FJ , UK . .,Molecular Catalysis, Faculty of Chemistry and Catalysis Research Center , Technical University Munich , Lichtenbergstr. 4 , 85748 Garching bei München , Germany
| | - Max W McMullon
- EaStCHEM School of Chemistry , University of Edinburgh , The King's Buildings , Edinburgh , EH9 3FJ , UK . .,Molecular Catalysis, Faculty of Chemistry and Catalysis Research Center , Technical University Munich , Lichtenbergstr. 4 , 85748 Garching bei München , Germany
| | - Alexander Pöthig
- Molecular Catalysis, Faculty of Chemistry and Catalysis Research Center , Technical University Munich , Lichtenbergstr. 4 , 85748 Garching bei München , Germany
| | - Fritz E Kühn
- Molecular Catalysis, Faculty of Chemistry and Catalysis Research Center , Technical University Munich , Lichtenbergstr. 4 , 85748 Garching bei München , Germany
| | - Andrew D Smith
- EaStCHEM School of Chemistry , University of St. Andrews , North Haugh, St. Andrews , KY16 9ST , UK, E-mail:
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23
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Anwander R, Dolg M, Edelmann FT. The difficult search for organocerium(iv) compounds. Chem Soc Rev 2018; 46:6697-6709. [PMID: 28913523 DOI: 10.1039/c7cs00147a] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
This Tutorial Review provides an overview of the historic and current development of the organometallic chemistry of cerium in its oxidation state 4+. Among the tetravalent lanthanide ions, only Ce4+ forms stable coordination compounds (e.g. (NH4)2[Ce(NO3)6]). Important fields of applications for cerium(iv) compounds include organic synthesis, bioinorganic chemistry, materials science, and industrial catalysis. In sharp contrast, organometallic cerium(iv) compounds are still exceedingly rare. The history of organocerium(iv) compounds is an exciting story of ups and downs. The so-called cerocene (= bis(η8-cyclooctatetraenyl) cerium) has been known since 1976. Other early reports e.g. about Cp4Ce (Cp = η5-cyclopentadienyl), were later disproven. However, significant progress in this field has been made in recent years through the use of carefully designed ligands and more sophisticated synthesis protocols. Taking the case of organocerium(iv) chemistry, this Tutorial Review also tries to exemplarily show how difficult synthetic and theoretical problems can eventually be solved through newly designed synthesis strategies (e.g. as accomplished for cyclopentadienyl and carbene derivatives) and a rewarding collaboration between synthetic and theoretical chemists (cf. the cerocene problem).
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Affiliation(s)
- Reiner Anwander
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, D-72076 Tübingen, Germany
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24
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Hameury S, de Frémont P, Braunstein P. Metal complexes with oxygen-functionalized NHC ligands: synthesis and applications. Chem Soc Rev 2018; 46:632-733. [PMID: 28083579 DOI: 10.1039/c6cs00499g] [Citation(s) in RCA: 150] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Ligand design has met with considerable success with both categories of hybrid ligands, which are characterized by chemically different donor groups, and of N-heterocyclic carbenes (NHCs). Their spectacular development and diversity are attracting worldwide interest and offers almost unlimited diversity and potential in e.g. coordination/organometallic main group and transition metal chemistry, catalysis, medicinal chemistry and materials science. This review aims at providing a comprehensive update on a specific class of ligands that has enjoyed much attention in the past few years, at the intersection between the two categories mentioned above, that of hybrid NHC ligands in which the functionality associated with the carbene donor is of the oxygen-donor type. For each type of oxygen-donor present in such chelating (Section 1) or bridging (Section 2) hybrid ligands, we will examine the synthesis, structures and reactivity of their metal complexes and their applications, with a special focus on homogeneous catalysis (Section 3). Thus, hydrogenation, C-H bond activation, C-C, C-N, C-O bond formation, hydrolysis of silanes, oligomerization, polymerization, metathesis, hydrosilylation, C-C bond cleavage, acceptorless dehydrogenation, dehalogenation/hydrogen transfer, oxidation and reduction reactions will be successively presented in a tabular manner, to facilitate an overview and a rapid identification of the relevant publications describing which metals associated with a given oxygen functionality are most suitable. The literature coverage includes the year 2015.
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Affiliation(s)
- Sophie Hameury
- Université de Strasbourg, CNRS, CHIMIE UMR 7177, Laboratoire de Chimie de Coordination, 4 rue Blaise Pascal, 67081 Strasbourg, France. and Universität Freiburg, Makromolekulare Chemie, Stefan-Meier-Str. 31, 79104 Freiburg, Germany
| | - Pierre de Frémont
- Université de Strasbourg, CNRS, CHIMIE UMR 7177, Laboratoire de Chimie de Coordination, 4 rue Blaise Pascal, 67081 Strasbourg, France. and Université de Strasbourg, CNRS, CHIMIE UMR 7177, Laboratoire de Synthèse, Réactivité et Catalyse Organométalliques, 4 rue Blaise Pascal, 67081 Strasbourg, France
| | - Pierre Braunstein
- Université de Strasbourg, CNRS, CHIMIE UMR 7177, Laboratoire de Chimie de Coordination, 4 rue Blaise Pascal, 67081 Strasbourg, France.
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25
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Werner D, Deacon GB, Junk PC, Anwander R. Pyrazolates advance cerium chemistry: a Ce III/Ce IV redox equilibrium with benzoquinone. Dalton Trans 2018; 46:6265-6277. [PMID: 28443879 DOI: 10.1039/c7dt00635g] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two stable cerium(iv) 3,5-dialkylpyrazolate complexes are presented, namely dimeric [Ce(Me2pz)4]2 (Me2pz = 3,5-dimethylpyrazolate) and monomeric Ce(tBu2pz)4 (tBu2pz = 3,5-di-tert-butylpyrazolate) along with their trivalent counterparts [Ce(Me2pz)3] and [Ce(tBu2pz)3]2. All complexes were obtained from protonolysis reactions employing the silylamide precursors Ce[N(SiHMe2)2]4 and Ce[N(SiMe3)2]3. Treatment of homoleptic CeIV and CeIII Me2pz complexes with 1,4-hydroquinone (H2hq) or 1,4-benzoquinone (bq), respectively, ultimately gave the same trimetallic CeIII species via a cerium redox equilibrium. The CeIII complex Ce3(Me2pz)5(pchd)2(L) (pchd = 1,4-bis(3,5-dimethylpyrazol-1-yl)cyclohex-2,5-diene-1,4-diolato; L = Me2pzH or (thf)2) results from a di-1,4-pyrazolyl attack on pre-coordinated bq. The reduction of bq by [Ce(Me2pz)3(thf)]2, and re-oxidation by the resulting CeIV species was supported by UV-vis spectroscopic investigations. Comparisons with the redox-innocent complexes [Ln(Me2pz)3(thf)]2 (Ln = La and Pr) revealed far less selective reactions with bq, giving hexametallic and octametallic rare-earth metal side products containing 2-Me2pz substituted hq ligands.
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Affiliation(s)
- Daniel Werner
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen (EKUT), Auf der Morgenstelle 18, 72076, Germany.
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26
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Friedrich J, Qiao Y, Maichle-Mössmer C, Schelter EJ, Anwander R. Redox-enhanced hemilability of a tris(tert-butoxy)siloxy ligand at cerium. Dalton Trans 2018; 47:10113-10123. [DOI: 10.1039/c8dt01878b] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Combined structural/electrochemical/computational studies of ceric Ce[OSi(OtBu)3]4 and cerous [Ce{OSi(OtBu)3}4][K(2.2.2-crypt)] suggest a redox-modulated coordination switch of a tris(tert-butoxy)siloxy ligand.
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Affiliation(s)
- Jochen Friedrich
- Institut für Anorganische Chemie
- Eberhard Karls Universität Tübingen
- 72076 Tübingen
- Germany
| | - Yusen Qiao
- P. Roy and Diana T. Vagelos Laboratories
- Department of Chemistry
- University of Pennsylvania
- Philadelphia
- USA
| | | | - Eric J. Schelter
- P. Roy and Diana T. Vagelos Laboratories
- Department of Chemistry
- University of Pennsylvania
- Philadelphia
- USA
| | - Reiner Anwander
- Institut für Anorganische Chemie
- Eberhard Karls Universität Tübingen
- 72076 Tübingen
- Germany
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27
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Kelly RP, Maron L, Scopelliti R, Mazzanti M. Reduction of a Cerium(III) Siloxide Complex To Afford a Quadruple-Decker Arene-Bridged Cerium(II) Sandwich. Angew Chem Int Ed Engl 2017; 56:15663-15666. [PMID: 29034561 DOI: 10.1002/anie.201709769] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Indexed: 12/30/2022]
Abstract
Organometallic multi-decker sandwich complexes containing f-elements remain rare, despite their attractive magnetic and electronic properties. The reduction of the CeIII siloxide complex, [KCeL4 ] (1; L=OSi(OtBu)3 ), with excess potassium in a THF/toluene mixture afforded a quadruple-decker arene-bridged complex, [K(2.2.2-crypt)]2 [{(KL3 Ce)(μ-η6 :η6 -C7 H8 )}2 Ce] (3). The structure of 3 features a [Ce(C7 H8 )2 ] sandwich capped by [KL3 Ce] moieties with a linear arrangement of the Ce ions. Structural parameters, UV/Vis/NIR data, and DFT studies indicate the presence of CeII ions involved in δ bonding between the Ce cations and toluene dianions. Complex 3 is a rare lanthanide multi-decker complex and the first containing non-classical divalent lanthanide ions. Moreover, oxidation of 1 by AgOTf (OTf=O3 SCF3 ) yielded the CeIV complex, [CeL4 ] (2), showing that siloxide ligands can stabilize Ce in three oxidation states.
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Affiliation(s)
- Rory P Kelly
- 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
| | - Rosario Scopelliti
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Marinella Mazzanti
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
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Kelly RP, Maron L, Scopelliti R, Mazzanti M. Reduction of a Cerium(III) Siloxide Complex To Afford a Quadruple-Decker Arene-Bridged Cerium(II) Sandwich. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201709769] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Rory P. Kelly
- 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
| | - Rosario Scopelliti
- Institut des Sciences et Ingénierie Chimiques; Ecole Polytechnique Fédérale de Lausanne (EPFL); 1015 Lausanne Switzerland
| | - Marinella Mazzanti
- Institut des Sciences et Ingénierie Chimiques; Ecole Polytechnique Fédérale de Lausanne (EPFL); 1015 Lausanne Switzerland
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29
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Novel cerium(IV)-diolate complex with a 13-nuclear cerium(IV)-oxo core: Synthesis, molecular structure and catalytic property for ε -caprolactone-polymerization. Polyhedron 2017. [DOI: 10.1016/j.poly.2017.06.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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30
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Werner D, Deacon GB, Junk PC, Anwander R. Facile Reversible Benzophenone Insertion into Rare‐Earth Metal Pyrazolate Complexes. Eur J Inorg Chem 2017. [DOI: 10.1002/ejic.201700635] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Daniel Werner
- Institut für Anorganische Chemie University of Tübingen (EKUT) Auf der Morgenstelle 18 72076 Tübingen Germany
| | - Glen B. Deacon
- School of Chemistry Monash University 3800 Clayton Victoria Australia
| | - Peter C. Junk
- College of Science and Engineering James Cook University 4811 Townsville Queensland Australia
| | - Reiner Anwander
- Institut für Anorganische Chemie University of Tübingen (EKUT) Auf der Morgenstelle 18 72076 Tübingen Germany
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Schneider D, Harmgarth N, Edelmann FT, Anwander R. Ceric Cyclopentadienides Bearing Alkoxy, Aryloxy, Chlorido, or Iodido Co-Ligands. Chemistry 2017; 23:12243-12252. [PMID: 28334455 DOI: 10.1002/chem.201700743] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Indexed: 12/23/2022]
Abstract
A series of heteroleptic tris(cyclopentadienyl) CeIV complexes has been isolated and crystallographically characterized, revealing the broad accessibility of such organocerium(IV) compounds. The oxidation of complexes CpMe3 Ce(thf) and Cp'3 Ce(thf) (CpMe =C5 H4 Me, Cp'=C5 H4 SiMe3 ), bearing monosubstituted electron-poor cyclopentadienyl ligands, with 0.5 equivalents of 1,4-benzoquinone or C2 Cl6 gave the cerium(IV) hydroquinolate complexes CpMe3 Ce(OC6 H4 O)CeCpMe3 and Cp'3 Ce(OC6 H4 O)CeCp'3 , or the chloride complexes CpMe3 CeCl and Cp'3 CeCl, respectively; the iodide complex Cp'3 CeI was obtained from the reaction of Cp'3 Ce(thf) with elemental iodine. The behavior of Cp'3 CeCl in salt metathesis protocols employing alkali metal amides or alkyl, alkoxide, and aryloxide reagents was investigated, which gave rise to the robust and isolable cerium(IV) alkoxide Cp'3 Ce(OtBu). Trivalent [Cp'2 CeCl]2 was synthesized by AlMe4 →Cl exchange utilizing Cp'2 Ce(AlMe4 ) and AlMe2 Cl. The reactivity of [Cp'2 CeCl]2 towards the oxidants Ph3 CCl, C2 Cl6 , 1,4-benzoquinone, and I2 has been assessed, and has provided useful information on CeIII /CeIV redox deactivation pathways. In addition to X-ray structure analysis, all the complexes were characterized by NMR, DRIFT (diffuse reflectance IR Fourier transform), and UV/Vis spectroscopy as well as elemental analysis. The tetravalent compounds were further analyzed for their magnetic susceptibility by using Evans' method.
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Affiliation(s)
- David Schneider
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
| | - Nicole Harmgarth
- Institut für Chemie, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106, Magdeburg, Germany
| | - Frank T Edelmann
- Institut für Chemie, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106, Magdeburg, Germany
| | - Reiner Anwander
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
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33
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Schneider D, Anwander R. Pentamethylcyclopentadienyl‐Supported Cerocene(III) Complexes. Eur J Inorg Chem 2017. [DOI: 10.1002/ejic.201601404] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- David Schneider
- Institut für Anorganische Chemie Eberhard Karls Universität Tübingen Auf der Morgenstelle 18 72076 Tübingen Germany
| | - Reiner Anwander
- Institut für Anorganische Chemie Eberhard Karls Universität Tübingen Auf der Morgenstelle 18 72076 Tübingen Germany
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Huang W, Diaconescu PL. Reactivity and Properties of Metal Complexes Enabled by Flexible and Redox-Active Ligands with a Ferrocene Backbone. Inorg Chem 2016; 55:10013-10023. [DOI: 10.1021/acs.inorgchem.6b01118] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Wenliang Huang
- Department of Chemistry and
Biochemistry, University of California, Los Angeles, 607 Charles
E Young Drive East, Los Angeles, California 90095, United States
| | - Paula L. Diaconescu
- Department of Chemistry and
Biochemistry, University of California, Los Angeles, 607 Charles
E Young Drive East, Los Angeles, California 90095, United States
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35
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Gregson M, Lu E, Tuna F, McInnes EJL, Hennig C, Scheinost AC, McMaster J, Lewis W, Blake AJ, Kerridge A, Liddle ST. Emergence of comparable covalency in isostructural cerium(iv)- and uranium(iv)-carbon multiple bonds. Chem Sci 2016; 7:3286-3297. [PMID: 29997821 PMCID: PMC6006499 DOI: 10.1039/c6sc00278a] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 02/04/2016] [Indexed: 11/26/2022] Open
Abstract
We report comparable levels of covalency in cerium- and uranium-carbon multiple bonds in the iso-structural carbene complexes [M(BIPMTMS)(ODipp)2] [M = Ce (1), U (2), Th (3); BIPMTMS = C(PPh2NSiMe3)2; Dipp = C6H3-2,6-iPr2] whereas for M = Th the M[double bond, length as m-dash]C bond interaction is much more ionic. On the basis of single crystal X-ray diffraction, NMR, IR, EPR, and XANES spectroscopies, and SQUID magnetometry complexes 1-3 are confirmed formally as bona fide metal(iv) complexes. In order to avoid the deficiencies of orbital-based theoretical analysis approaches we probed the bonding of 1-3 via analysis of RASSCF- and CASSCF-derived densities that explicitly treats the orbital energy near-degeneracy and overlap contributions to covalency. For these complexes similar levels of covalency are found for cerium(iv) and uranium(iv), whereas thorium(iv) is found to be more ionic, and this trend is independently found in all computational methods employed. The computationally determined trends in covalency of these systems of Ce ∼ U > Th are also reproduced in experimental exchange reactions of 1-3 with MCl4 salts where 1 and 2 do not exchange with ThCl4, but 3 does exchange with MCl4 (M = Ce, U) and 1 and 2 react with UCl4 and CeCl4, respectively, to establish equilibria. This study therefore provides complementary theoretical and experimental evidence that contrasts to the accepted description that generally lanthanide-ligand bonding in non-zero oxidation state complexes is overwhelmingly ionic but that of uranium is more covalent.
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Affiliation(s)
- Matthew Gregson
- School of Chemistry , The University of Manchester , Oxford Road , Manchester , M13 9PL , UK .
| | - Erli Lu
- School of Chemistry , The University of Manchester , Oxford Road , Manchester , M13 9PL , UK .
| | - Floriana Tuna
- EPSRC National UK EPR Facility , School of Chemistry and Photon Science Institute , The University of Manchester , Oxford Road , Manchester , M13 9PL , UK
| | - Eric J L McInnes
- EPSRC National UK EPR Facility , School of Chemistry and Photon Science Institute , The University of Manchester , Oxford Road , Manchester , M13 9PL , UK
| | - Christoph Hennig
- Helmholtz-Zentrum Dresden-Rossendorf , Institute of Resource Ecology , Bautzner Landstrasse 400 , D-01314 Dresden , Germany
- The Rossendorf Beamline , ESRF , BP 220 , F-38043 Grenoble , France
| | - Andreas C Scheinost
- Helmholtz-Zentrum Dresden-Rossendorf , Institute of Resource Ecology , Bautzner Landstrasse 400 , D-01314 Dresden , Germany
- The Rossendorf Beamline , ESRF , BP 220 , F-38043 Grenoble , France
| | - Jonathan McMaster
- School of Chemistry , University of Nottingham , University Park , Nottingham , NG7 2RD , UK
| | - William Lewis
- School of Chemistry , University of Nottingham , University Park , Nottingham , NG7 2RD , UK
| | - Alexander J Blake
- School of Chemistry , University of Nottingham , University Park , Nottingham , NG7 2RD , UK
| | - Andrew Kerridge
- Department of Chemistry , Lancaster University , Lancaster , LA1 4YB , UK .
| | - Stephen T Liddle
- School of Chemistry , The University of Manchester , Oxford Road , Manchester , M13 9PL , UK .
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36
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Robinson JR, Qiao Y, Gu J, Carroll PJ, Walsh PJ, Schelter EJ. The role of dynamic ligand exchange in the oxidation chemistry of cerium(iii). Chem Sci 2016; 7:4537-4547. [PMID: 30155100 PMCID: PMC6016327 DOI: 10.1039/c5sc04897d] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 03/22/2016] [Indexed: 01/09/2023] Open
Abstract
We report the exchange processes and reactivity of 1-Ce(het), which establish the effects of ligand redistribution and ligand reorganization in CeIII oxidation chemistry.
The CeIII/IV couple is useful for many applications in organic, inorganic, and materials chemistry. However, attaining a general method to access both oxidations states through reversible solution redox chemistry remains challenging. Herein we report the synthesis, characterization, and oxidation chemistry of the novel Ce/Li REMB heterochiral diastereomer, 1-Ce(het). The solution exchange processes of 1-RE(het) (RE = Ce and Yb) were investigated to estimate rates of ligand and cation exchange relevant in homochiral and heterochiral frameworks. A detailed mechanistic investigation following the solution dynamics of 1-Ce(het) revealed reactivity controlled both by ligand reorganization and redistribution processes. Ligand reorganization was responsible for the kinetics associated with the chemical oxidation reaction, whereas ligand redistribution and exchange dictated the isolated products.
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Affiliation(s)
- Jerome R Robinson
- P. Roy and Diana T. Vagelos Laboratories , Department of Chemistry , University of Pennsylvania , Philadelphia , PA 19104 , USA . ;
| | - Yusen Qiao
- P. Roy and Diana T. Vagelos Laboratories , Department of Chemistry , University of Pennsylvania , Philadelphia , PA 19104 , USA . ;
| | - Jun Gu
- P. Roy and Diana T. Vagelos Laboratories , Department of Chemistry , University of Pennsylvania , Philadelphia , PA 19104 , USA . ;
| | - Patrick J Carroll
- P. Roy and Diana T. Vagelos Laboratories , Department of Chemistry , University of Pennsylvania , Philadelphia , PA 19104 , USA . ;
| | - Patrick J Walsh
- P. Roy and Diana T. Vagelos Laboratories , Department of Chemistry , University of Pennsylvania , Philadelphia , PA 19104 , USA . ;
| | - Eric J Schelter
- P. Roy and Diana T. Vagelos Laboratories , Department of Chemistry , University of Pennsylvania , Philadelphia , PA 19104 , USA . ;
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Williams UJ, Schneider D, Dorfner WL, Maichle-Mössmer C, Carroll PJ, Anwander R, Schelter EJ. Variation of electronic transitions and reduction potentials of cerium(IV) complexes. Dalton Trans 2015; 43:16197-206. [PMID: 25148646 DOI: 10.1039/c4dt01386g] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The trivalent compound K[Ce[N(SiHMe2)2]4] was synthesized and oxidized, providing a convenient route to the reported cerium(IV) compound Ce[N(SiHMe2)2]4. Protonolysis reactions of Ce[N(SiHMe2)2]4 with tert-butanol, substituted benzyl alcohols, and 2,6-diphenylphenol yielded the neutral tetravalent compounds Ce(O(t)Bu)4(py)2, Ce2(OCH2C6R5)8(thf)2 (R = Me, F), and Ce(Odpp)4 (dpp = 2,6-(C6H5)2-C6H3). Spectroscopic and electrochemical characterization of the monometallic cerium(IV) silylamide, alkoxide, and aryloxide compounds revealed variable ligand-to-metal charge transfer transitions and metal-based reduction potentials. Computational bonding analyses were performed to complement the physical characterization of the complexes.
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Affiliation(s)
- Ursula J Williams
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, USA.
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39
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Arnold PL, Cadenbach T, Marr IH, Fyfe AA, Bell NL, Bellabarba R, Tooze RP, Love JB. Homo- and heteroleptic alkoxycarbene f-element complexes and their reactivity towards acidic N-H and C-H bonds. Dalton Trans 2015; 43:14346-58. [PMID: 24920060 DOI: 10.1039/c4dt01442a] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The reactivity of a series of organometallic rare earth and actinide complexes with hemilabile NHC-ligands towards substrates with acidic C-H and N-H bonds is described. The synthesis, characterisation and X-ray structures of the new heteroleptic mono- and bis(NHC) cyclopentadienyl complexes LnCp2(L) 1 (Ln = Sc, Y, Ce; L = alkoxy-tethered carbene [OCMe2CH2(1-C{NCHCHN(i)Pr})]), LnCp(L)2 (Ln = Y) , and the homoleptic tetrakis(NHC) complex Th(L)4 4 are described. The reactivity of these complexes, and of the homoleptic complexes Ln(L)3 (Ln = Sc 3, Ce), with E-H substrates is described, where EH = pyrrole C4H4NH, indole C8H6NH, diphenylacetone Ph2CC(O)Me, terminal alkynes RC≡CH (R = Me3Si, Ph), and cyclopentadiene C5H6. Complex 1-Y heterolytically cleaves and adds pyrrole and indole N-H across the metal carbene bond, whereas 1-Ce does not, although 3 and 4 form H-bonded adducts. Complexes 1-Y and 1-Sc form adducts with CpH without cleaving the acidic C-H bond, 1-Ce cleaves the Cp-H bond, but 2 reacts to form the very rare H(+)-[C5H5](-)-H(+) motif. Complex 1-Ce cleaves alkyne C-H bonds but the products rearrange upon formation, while complex 1-Y cleaves the C-H bond in diphenylacetone forming a product which rearranges to the Y-O bonded enolate product.
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Affiliation(s)
- Polly L Arnold
- EaStCHEM School of Chemistry, University of Edinburgh, The King's Buildings, Edinburgh, EH9 3JJ, UK.
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40
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Schneider D, Spallek T, Maichle-Mössmer C, Törnroos KW, Anwander R. Cerium tetrakis(diisopropylamide)--a useful precursor for cerium(IV) chemistry. Chem Commun (Camb) 2015; 50:14763-6. [PMID: 25317924 DOI: 10.1039/c4cc06228k] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Homoleptic cerium(IV) diisopropylamide was synthesized via oxidation of ate complex Ce(NiPr2)4Li(thf) with trityl chloride or hexachloroethane. Due to its ready accessibility, and high pKa value of the proligand HNiPr2, Ce(NiPr2)4 features a promising candidate for protonolysis reactions, as shown for the synthesis of dimeric cerium(IV) tetrakis(1,1,3,3-N,N,N',N'-tetramethylguanidinate).
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Affiliation(s)
- David Schneider
- Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany.
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41
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Tarakanova EN, Levitskiy OA, Magdesieva TV, Tarakanov PA, Pushkarev VE, Tomilova LG. Cerium bis(tetradiazepinoporphyrazinate): synthesis and peculiarities of spectral and electrochemical behavior. NEW J CHEM 2015. [DOI: 10.1039/c5nj00884k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A cerium sandwich double-decker complex of tetradiazepinoporphyrazine was synthesized for the first time, which exhibited specific spectral and electrochemical properties.
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Affiliation(s)
- Ekaterina N. Tarakanova
- Institute of Physiologically Active Compounds
- Russian Academy of Sciences
- 142432 Chernogolovka
- Russian Federation
| | - Oleg A. Levitskiy
- Department of Chemistry
- M.V. Lomonosov Moscow State University
- 119991 Moscow
- Russian Federation
| | - Tatiana V. Magdesieva
- Department of Chemistry
- M.V. Lomonosov Moscow State University
- 119991 Moscow
- Russian Federation
| | - Pavel A. Tarakanov
- Institute of Physiologically Active Compounds
- Russian Academy of Sciences
- 142432 Chernogolovka
- Russian Federation
| | - Victor E. Pushkarev
- Institute of Physiologically Active Compounds
- Russian Academy of Sciences
- 142432 Chernogolovka
- Russian Federation
| | - Larisa G. Tomilova
- Institute of Physiologically Active Compounds
- Russian Academy of Sciences
- 142432 Chernogolovka
- Russian Federation
- Department of Chemistry
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Arnold PL, Bell NL, Marr IH, She S, Hamilton J, Fraser C, Wang K. Protonolysis and thermolysis reactions of functionalised NHC-carbene boranes and borates. Dalton Trans 2014; 43:15419-28. [PMID: 25188908 DOI: 10.1039/c4dt01464b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A set of β-ketoimidazolium and β-ketoimidazolinium salts of the general formula [R(1)C(O)CH2{CH[NCR(3)CR(3)N(R(2))]}]X (R(1) = (t)Bu, naphth; R(2) = (i)Pr, Mes, (t)Bu; R(3) = H, Me, (H)2; X = Cl, Br) show contrasting reactivity with superhydride bases MHBEt3; two are reduced to chiral β-alcohol carbene-boranes R(1)CH(OH)CH2{C(BEt3)[NCR(3)CR(3)N(R(2))]} 2 (R(1) = (t)Bu; R(2) = (i)Pr, Mes; R(3) = H), two with bulky R(2) substituents are reduced to chiral β-borate imidazolium salts [R(1)CH(OBEt3)CH2{CH[NCR(3)CR(3)N(R(2))]}]X 3 (R(1) = (t)Bu, naphth; R(2) = Mes, (t)Bu; R(3) = H, Me; X = Cl, Br), and the two saturated heterocycle derivatives remain unreduced but form carbene-borane adducts R(1)C(O)CH2{C(BEt3)[NCR(3)CR(3)N(R(2))]} 4 (R(1) = (t)Bu, naphth; R(2) = Mes; R(3) = (H)2). Heating solutions of the imidazolium borates 3 results in the elimination of ethane, in the first example of organic borates functioning as Brønsted bases and forming carbene boranes R(1)CH(OBEt2)CH2{C[NCR(3)CR(3)N(R(2))]} 5 (R(1) = naphth; R(2) = Mes; R(3) = Me). The 'abnormal' carbene borane of the form 2 R(1)CH(OH)CH2{CH[NC(BEt3)CR(3)N(R(2))]} (R(1) = (t)Bu; R(2) = (t)Bu; R(3) = H), is also accessible by thermolysis of 3, suggesting that the carbene-borane alcohol is a more thermodynamically stable combination than the zwitterionic imidazolium borate. High-temperature thermolysis also can result in complete cleavage of the alcohol arm, eliminating tert-butyloxirane and forming the B-N bound imidazolium borate 7. The strong dependence of reaction products on the steric and electronic properties of each imidazole precursor molecule is discussed.
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Affiliation(s)
- Polly L Arnold
- EaStCHEM School of Chemistry, University of Edinburgh, The King's Buildings, Edinburgh, EH9 3JJ, UK.
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43
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Williams UJ, Carroll PJ, Schelter EJ. Synthesis and analysis of a family of cerium(IV) halide and pseudohalide compounds. Inorg Chem 2014; 53:6338-45. [PMID: 24874078 DOI: 10.1021/ic500969r] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The first complete series of isostructural cerium(IV) halide complexes in a conserved ligand framework was isolated by halogen-exchange reactions of CeF[N(SiMe3)2]3 with Me3SiX (X = Cl(-), Br(-), I(-)). The use of Me3SiX reagents represents a useful method for obtaining cerium(IV) complexes. Spectroscopic, electrochemical, and computational analyses were used to describe the effects of halide coordination on the cerium(IV) metal center. Cerium(IV) complexes of the pseudohalide ligands: N3(-) and NCS(-) were also synthesized and evaluated in comparison to the halide congeners. The results showed that the complexes exhibited reduction potentials and electronic absorption energies that varied with the identity of the halide or pseudohalide ligand.
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Affiliation(s)
- Ursula J Williams
- 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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44
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Piro NA, Robinson JR, Walsh PJ, Schelter EJ. The electrochemical behavior of cerium(III/IV) complexes: Thermodynamics, kinetics and applications in synthesis. Coord Chem Rev 2014. [DOI: 10.1016/j.ccr.2013.08.034] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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45
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Arnold PL, Marr IA, Zlatogorsky S, Bellabarba R, Tooze RP. Activation of carbon dioxide and carbon disulfide by a scandium N-heterocyclic carbene complex. Dalton Trans 2014; 43:34-7. [DOI: 10.1039/c3dt52762j] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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46
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Robinson JR, Gordon Z, Booth CH, Carroll PJ, Walsh PJ, Schelter EJ. Tuning Reactivity and Electronic Properties through Ligand Reorganization within a Cerium Heterobimetallic Framework. J Am Chem Soc 2013; 135:19016-24. [DOI: 10.1021/ja410688w] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Jerome R. Robinson
- P.
Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Zachary Gordon
- P.
Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Corwin H. Booth
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Patrick J. Carroll
- P.
Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Patrick J. Walsh
- P.
Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Eric J. Schelter
- P.
Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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Affiliation(s)
| | - Patrick Eisenberger
- Department of Chemistry, Queen’s University, 90 Bader Lane, Kingston, Ontario K7L 3N6, Canada
| | - Cathleen M. Crudden
- Department of Chemistry, Queen’s University, 90 Bader Lane, Kingston, Ontario K7L 3N6, Canada
- Institute of Transformative
Bio-Molecules (WPI-ITbM), Nagoya University, Chikusa, Nagoya, Japan
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48
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Gregson M, Lu E, McMaster J, Lewis W, Blake AJ, Liddle ST. A Cerium(IV)-Carbon Multiple Bond. Angew Chem Int Ed Engl 2013; 52:13016-9. [DOI: 10.1002/anie.201306984] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Indexed: 11/09/2022]
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49
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Gregson M, Lu E, McMaster J, Lewis W, Blake AJ, Liddle ST. A Cerium(IV)-Carbon Multiple Bond. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201306984] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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50
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Iversen KJ, Wilson DJD, Dutton JL. Comparison of the Mechanism of Borane, Silane, and Beryllium Hydride Ring Insertion into N-Heterocyclic Carbene C–N Bonds: A Computational Study. Organometallics 2013. [DOI: 10.1021/om400800d] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kalon J. Iversen
- Department
of Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - David J. D. Wilson
- Department
of Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Jason L. Dutton
- Department
of Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| |
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