1
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Tsurugi H, Akiyama T, Frye CW, Kakiuchi Y, Mashima K, Tonks IA. Evaluation of Tungsten Catalysis among Early Transition Metals for N-Aryl-2,3,4,5-tetraarylpyrrole Synthesis: Modular Access to N-Doped π-Conjugated Material Precursors. Inorg Chem 2024; 63:3037-3046. [PMID: 38300807 PMCID: PMC11059426 DOI: 10.1021/acs.inorgchem.3c03858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2024]
Abstract
Low-valent tungsten species generated from WCl6 and N,N'-bis(trimethylsilyl)-2,5-dimethyldihydropyrazine (Si-Me2-DHP) promotes the catalytic formation of N-phenyl-2,3,4,5-tetraarylpyrroles 3aa-ka from diarylacetylenes 1a-k and azobenzene (2a). An initial catalyst activation process is a three-electron reduction of WCl6 with Si-Me2-DHP to afford transient 'WCl3' species. Catalytically active bis(imido)tungsten(VI) species via successive one-electron reduction and N═N bond cleavage of 2a was revealed by isolating W(═NPh)2Cl2(PMe2Ph)2 from imidotungsten(V) trichloride and 2a in the presence of PMe2Ph. The superior catalytic activity of the tungsten catalyst was clarified by a density functional theory study: activation energies for the key three steps, [2 + 2]-cycloaddition of W═NPh and diarylacetylene to form (iminoalkylidene)tungsten species, enyne metathesis with second diarylacetylene, and C-N bond formation, are reasonable values for the catalytic reaction at 180 °C. In addition, this tungsten catalyst overcame two distinct deactivation processes: α-enediamido formation and aggregation of the low-valent species, both of which were observed for previously developed vanadium and titanium catalysts. We also demonstrated the synthetic utility of pentaarylpyrroles 3aa and 3ba as well as N-(2-bromophenyl)-2,3,4,5-tetraarylpyrrole 3ab by derivatizing their π-conjugated compounds 9aa, 10ba, and 11ab.
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Affiliation(s)
- Hayato Tsurugi
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
- Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, Suita, Osaka 565-0871, Japan
| | - Takuya Akiyama
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Connor W. Frye
- Department of Chemistry, University of Minnesota–Twin Cities, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Yuya Kakiuchi
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Kazushi Mashima
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Ian A. Tonks
- Department of Chemistry, University of Minnesota–Twin Cities, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
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2
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Leitner D, Wittwer B, Neururer FR, Seidl M, Wurst K, Tambornino F, Hohloch S. Expanding the Utility of β-Diketiminate Ligands in Heavy Group VI Chemistry of Molybdenum and Tungsten. Organometallics 2023; 42:1411-1424. [PMID: 37388273 PMCID: PMC10302891 DOI: 10.1021/acs.organomet.3c00056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Indexed: 07/01/2023]
Abstract
We report the synthesis of 17 molybdenum and tungsten complexes supported by the ubiquitous BDI ligand framework (BDI = β-diketiminate). The focal entry point is the synthesis of four molybdenum and tungsten(V) BDI complexes of the general formula [MO(BDIR)Cl2] [M = Mo, R = Dipp (1); M = W, R = Dipp (2); M = Mo, R = Mes (3); M = W, R = Mes (4)] synthesized by the reaction between MoOCl3(THF)2 or WOCl3(THF)2 and LiBDIR. Reactivity studies show that the BDIDipp complexes are excellent precursors toward adduct formation, reacting smoothly with dimethylaminopyridine (DMAP) and triethylphosphine oxide (OPEt3). No reaction with small phosphines has been observed, strongly contrasting the chemistry of previously reported rhenium(V) complexes. Additionally, the complexes 1 and 2 are good precursors for salt metathesis reactions. While 1 can be chemically reduced to the first stable example of a Mo(IV) BDI complex 15, reduction of 2 resulted in degradation of the BDI ligand via a nitrene transfer reaction, leading to MAD (4-((2,6-diisopropylphenyl)imino)pent-2-enide) supported tungsten(V) and tungsten(VI) complexes 16 and 17. All reported complexes have been thoroughly studied by VT-NMR and (heteronuclear) NMR spectroscopy, as well as UV-vis and EPR spectroscopy, IR spectroscopy, and X-ray diffraction analysis.
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Affiliation(s)
- Daniel Leitner
- Faculty
of Chemistry and Pharmacy, Institute for General, Inorganic and Theoretical
Chemistry, University of Innsbruck, Innrain 80−82, Innsbruck 6020 Austria
| | - Benjamin Wittwer
- Faculty
of Chemistry and Pharmacy, Institute for General, Inorganic and Theoretical
Chemistry, University of Innsbruck, Innrain 80−82, Innsbruck 6020 Austria
| | - Florian R. Neururer
- Faculty
of Chemistry and Pharmacy, Institute for General, Inorganic and Theoretical
Chemistry, University of Innsbruck, Innrain 80−82, Innsbruck 6020 Austria
| | - Michael Seidl
- Faculty
of Chemistry and Pharmacy, Institute for General, Inorganic and Theoretical
Chemistry, University of Innsbruck, Innrain 80−82, Innsbruck 6020 Austria
| | - Klaus Wurst
- Faculty
of Chemistry and Pharmacy, Institute for General, Inorganic and Theoretical
Chemistry, University of Innsbruck, Innrain 80−82, Innsbruck 6020 Austria
| | - Frank Tambornino
- Fachbereich
Chemie and Wissenschaftlichen Zentrum für Materialwissenschaften
(WZMW), Phillips-University Marburg, Hans-Meerwein-Straße 4, 35043 Marburg, Germany
| | - Stephan Hohloch
- Faculty
of Chemistry and Pharmacy, Institute for General, Inorganic and Theoretical
Chemistry, University of Innsbruck, Innrain 80−82, Innsbruck 6020 Austria
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3
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Neururer F, Huter K, Seidl M, Hohloch S. Reactivity and Structure of a Bis-phenolate Niobium NHC Complex. ACS ORGANIC & INORGANIC AU 2022; 3:59-71. [PMID: 36748079 PMCID: PMC9896488 DOI: 10.1021/acsorginorgau.2c00028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 12/12/2022]
Abstract
We report the facile synthesis of a rare niobium(V) imido NHC complex with a dianionic OCO-pincer benzimidazolylidene ligand (L 1 ) with the general formula [NbL 1 (N t Bu)PyCl] 1-Py. We achieved this by in situ deprotonation of the corresponding azolium salt [H 3 L 1 ][Cl] and subsequent reaction with [Nb(N t Bu)Py 2 Cl 3 ]. The pyridine ligand in 1-Py can be removed by the addition of B(C6F5)3 as a strong Lewis acid leading to the formation of the pyridine-free complex 1. In contrast to similar vanadium(V) complexes, complex 1-Py was found to be a good precursor for various salt metathesis reactions, yielding a series of chalcogenido and pnictogenido complexes with the general formula [ NbL 1 (N t Bu)Py(EMes)] (E = O (2), S (3), NH (4), and PH (5)). Furthermore, complex 1-Py can be converted to alkyl complex (6) with 1 equiv of neosilyl lithium as a transmetallation agent. Addition of a second equivalent yields a new trianionic supporting ligand on the niobium center (7) in which the benzimidazolylidene ligand is alkylated at the former carbene carbon atom. The latter is an interesting chemically "noninnocent" feature of the benzimidazolylidene ligand potentially useful in catalysis and atom transfer reactions. Addition of mesityl lithium to 1-Py gives the pyridine-free aryl complex 8, which is stable toward "overarylation" by an additional equivalent of mesityl lithium. Electrochemical investigation revealed that complexes 1-Py and 1 are inert toward reduction in dichloromethane but show two irreversible reduction processes in tetrahydrofuran as a solvent. However, using standard reduction agents, e.g., KC8, K-mirror, and Na/Napht, no reduced products could be isolated. All complexes have been thoroughly studied by various techniques, including 1H-, 13C{1H}-, and 1H-15N HMBC NMR spectroscopy, IR spectroscopy, and X-ray diffraction analysis.
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4
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Fostvedt JI, Mendoza J, Lopez-Flores S, Alcantar D, Bergman RG, Arnold J. Engendering reactivity at group 5-heteroatom multiple bonds via π-loading. Chem Sci 2022; 13:8224-8242. [PMID: 35919706 PMCID: PMC9297388 DOI: 10.1039/d2sc02706b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 06/20/2022] [Indexed: 11/28/2022] Open
Abstract
In this Perspective, we discuss the strategy of π-loading, i.e., coordination of two or more strongly π-donating ligands to a single metal center, as it applies to promoting reactivity at group 5 transition metal-imido groups. When multiple π-donor ligands compete to interact with the same symmetrically-available metal dπ orbitals, the energy of the imido-based frontier molecular orbitals increases, leading to amplified imido-based reactivity. This strategy is of particular relevance to group 5 metals, as mono(imido) complexes of these metals tend to be inert at the imido group. Electronic structure studies of group 5 bis(imido) complexes are presented, and examples of catalytically and stoichiometrically active group 5 bis(imido) and chalcogenido-imido complexes are reviewed. These examples are intended to encourage future work exploring π-loaded bis(imido) systems of the group 5 triad.
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Affiliation(s)
- Jade I Fostvedt
- Department of Chemistry, University of California Berkeley CA 94720 USA
| | - Jocelyne Mendoza
- Department of Chemistry, University of California Berkeley CA 94720 USA
| | - Sacy Lopez-Flores
- College of Letters & Science, University of California Berkeley CA 94720 USA
| | - Diego Alcantar
- Department of Chemistry, University of California Berkeley CA 94720 USA
| | - Robert G Bergman
- Department of Chemistry, University of California Berkeley CA 94720 USA
| | - John Arnold
- Department of Chemistry, University of California Berkeley CA 94720 USA
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5
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Jain A, Fostvedt JI, Kriegel BM, Small DW, Grant LN, Bergman RG, Arnold J. [3 + 2] Cycloadditions and Retrocycloadditions of Niobium Imido Complexes: An Experimental and Computational Mechanistic Study. Inorg Chem 2022; 61:6574-6583. [PMID: 35436407 DOI: 10.1021/acs.inorgchem.2c00428] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
We demonstrate reactivity between a β-diketiminate-supported niobium(III) imido complex and alkyl azides to form niobatetrazene complexes (BDI)Nb(NtBu)(RNNNNR) (BDI = N,N-bis(2,6-diisopropylphenyl)-3,5-dimethyl-β-diketiminate; R = cyclohexyl (1), benzyl (2)). Intriguingly, niobatetrazene complexes 1 and 2 can be interconverted via addition of an appropriate alkyl azide, likely through a series of concerted [3 + 2] cycloaddition and retrocycloaddition reactions in which π-loaded bis(imido) intermediates are formed. The bis(imido) intermediates were trapped upon addition of alkyl isocyanides to yield five-coordinate bis(imido) complexes (BDI)Nb(NtBu)(NCy)(CNR) (R = tert-butyl (4a), cyclohexyl (4b)). Two computational methods─density functional theory and density functional tight binding (DFTB)─were employed to calculate the lowest energy pathway across the potential energy surface for this multistep transformation. Reaction path calculations for individual cycloaddition or retrocycloaddition processes along the multistep reaction pathway showed that these transformations occur via a concerted, yet highly asynchronous mechanism, in which the two bond-breaking or -making events do not occur simultaneously. The use of the DFTB method in this work highlights its advantages and utility for studying transition metal systems.
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Affiliation(s)
- Anukta Jain
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Jade I Fostvedt
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Benjamin M Kriegel
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - David W Small
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Lauren N Grant
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Robert G Bergman
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - John Arnold
- Department of Chemistry, University of California, Berkeley, California 94720, United States
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6
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Zhizhko PA, Bushkov NS, Pichugov AV, Zarubin DN. Oxo/imido heterometathesis: From molecular stoichiometric studies to well-defined heterogeneous catalysts. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.214112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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7
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Fostvedt JI, Grant LN, Kriegel BM, Obenhuber AH, Lohrey TD, Bergman RG, Arnold J. 1,2-Addition and cycloaddition reactions of niobium bis(imido) and oxo imido complexes. Chem Sci 2020; 11:11613-11632. [PMID: 34094408 PMCID: PMC8162998 DOI: 10.1039/d0sc03489d] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 09/28/2020] [Indexed: 11/21/2022] Open
Abstract
The bis(imido) complexes (BDI)Nb(N t Bu)2 and (BDI)Nb(N t Bu)(NAr) (BDI = N,N'-bis(2,6-diisopropylphenyl)-3,5-dimethyl-β-diketiminate; Ar = 2,6-diisopropylphenyl) were shown to engage in 1,2-addition and [2 + 2] cycloaddition reactions with a wide variety of substrates. Reaction of the bis(imido) complexes with dihydrogen, silanes, and boranes yielded hydrido-amido-imido complexes via 1,2-addition across Nb-imido π-bonds; some of these complexes were shown to further react via insertion of carbon dioxide to give formate-amido-imido products. Similarly, reaction of (BDI)Nb(N t Bu)2 with tert-butylacetylene yielded an acetylide-amido-imido complex. In contrast to these results, many related mono(imido) Nb BDI complexes do not exhibit 1,2-addition reactivity, suggesting that π-loading plays an important role in activating the Nb-N π-bonds toward addition. The same bis(imido) complexes were also shown to engage in [2 + 2] cycloaddition reactions with oxygen- and sulfur-containing heteroallenes to give carbamate- and thiocarbamate-imido complexes: some of these complexes readily dimerized to give bis-μ-sulfido, bis-μ-iminodicarboxylate, and bis-μ-carbonate complexes. The mononuclear carbamate imido complex (BDI)Nb(NAr)(N( t Bu)CO2) (12) could be induced to eject tert-butylisocyanate to generate a four-coordinate terminal oxo imido intermediate, which could be trapped as the five-coordinate pyridine or DMAP adduct. The DMAP adducted oxo imido complex (BDI)NbO(NAr)(DMAP) (16) was shown to engage in 1,2-addition of silanes across the Nb-oxo π-bond; this represents a new reaction pathway in group 5 chemistry.
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Affiliation(s)
- Jade I Fostvedt
- Department of Chemistry, University of California Berkeley CA 94720 USA
| | - Lauren N Grant
- Department of Chemistry, University of California Berkeley CA 94720 USA
| | | | | | - Trevor D Lohrey
- Department of Chemistry, University of California Berkeley CA 94720 USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory 1 Cyclotron Road Berkeley CA 94720 USA
| | - Robert G Bergman
- Department of Chemistry, University of California Berkeley CA 94720 USA
| | - John Arnold
- Department of Chemistry, University of California Berkeley CA 94720 USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory 1 Cyclotron Road Berkeley CA 94720 USA
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8
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Kawakita K, Kakiuchi Y, Tsurugi H, Mashima K, Parker BF, Arnold J, Tonks IA. Reactivity of terminal imido complexes of group 4-6 metals: stoichiometric and catalytic reactions involving cycloaddition with unsaturated organic molecules. Coord Chem Rev 2020; 407:213118. [PMID: 32863399 PMCID: PMC7453927 DOI: 10.1016/j.ccr.2019.213118] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Imido complexes of early transition metals are key intermediates in the synthesis of many nitrogen-containing organic compounds. The metal-nitrogen double bond of the imido moiety undergoes [2+2] cycloaddition reactions with various unsaturated organic molecules to form new nitrogen-carbon and nitrogen-heteroatom bonds. This review article focuses on reactivity of the terminal imido complexes of Group 4-6 metals, summarizing their stoichiometric reactions and catalytic applications for a variety of reactions including alkyne hydroamination, alkyne carboamination, pyrrole formation, imine metathesis, and condensation reactions of carbonyl compounds with isocyanates.
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Affiliation(s)
- Kento Kawakita
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Yuya Kakiuchi
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Hayato Tsurugi
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Kazushi Mashima
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Bernard F. Parker
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - John Arnold
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Ian A. Tonks
- Department of Chemistry, University of Minnesota—Twin Cities, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
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9
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Kurogi T, Chu J, Chen Y, Mindiola DJ. Neutral and Anionic Monomeric Zirconium Imides Prepared via Selective C=N Bond Cleavage of a Multidentate and Sterically Demanding β‐Diketiminato Ligand. Chem Asian J 2019; 14:2629-2638. [DOI: 10.1002/asia.201900451] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 05/13/2019] [Indexed: 11/10/2022]
Affiliation(s)
- Takashi Kurogi
- Department of ChemistryUniversity of Pennsylvania 231 South 34th Street Philadelphia PA 19104 USA
| | - Jiaxiang Chu
- State Key Laboratory of Organometallic ChemistryShanghai Institute of Organic Chemistry, Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 P. R. China
| | - Yaofeng Chen
- State Key Laboratory of Organometallic ChemistryShanghai Institute of Organic Chemistry, Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 P. R. China
| | - Daniel J. Mindiola
- Department of ChemistryUniversity of Pennsylvania 231 South 34th Street Philadelphia PA 19104 USA
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10
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Kriegel BM, Kaltsoyannis N, Chatterjee R, Bergman RG, Arnold J. Synthesis and Redox Chemistry of a Tantalum Alkylidene Complex Bearing a Metallaimidazole Ring. Organometallics 2017. [DOI: 10.1021/acs.organomet.7b00448] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Benjamin M. Kriegel
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Nikolas Kaltsoyannis
- School
of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Ruchira Chatterjee
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Robert G. Bergman
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - John Arnold
- Department of Chemistry, University of California, Berkeley, California 94720, United States
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11
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Lohrey TD, Bergman RG, Arnold J. Oxygen Atom Transfer and Intramolecular Nitrene Transfer in a Rhenium β-Diketiminate Complex. Inorg Chem 2016; 55:11993-12000. [DOI: 10.1021/acs.inorgchem.6b02122] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Trevor D. Lohrey
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Robert G. Bergman
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - John Arnold
- Department of Chemistry, University of California, Berkeley, California 94720, United States
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12
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Abubekerov M, Eymann LYM, Gianetti TL, Arnold J. Activation of heteroallenes by coordinatively unsaturated nickel(ii) alkyl complexes supported by the hydrotris(3-phenyl-5-methyl)pyrazolyl borate (Tp(Ph,Me)) ligand. Dalton Trans 2016; 45:14581-90. [PMID: 27334096 DOI: 10.1039/c6dt01585a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Activation of sulfur containing heteroallenes by nickel(ii) alkyl complexes supported by the bulky hydrotris(3-phenyl-5-methylpyrazolyl)borate (Tp(Ph,Me)) ligand is described. Exposure of Tp(Ph,Me)NiCH2Ph (1a) and Tp(Ph,Me)NiCH2Si(CH3)3 (1b) to CS2 resulted in formation of the insertion products Tp(Ph,Me)Ni(η(2)-CS2)CH2Ph (2a) and Tp(Ph,Me)Ni(η(2)-CS2)CH2Si(CH3)3 (2b) in moderate yields. Reaction of 1a and MeNCS produced two species in a 1 : 1 ratio, identified as Tp(Ph,Me)Ni(η(2)-MeNC)CH2Ph (3) and Tp(Ph,Me)Ni(η(2)-MeNCS)SCH2Ph (4). Isolation of the unexpected insertion product (3) prompted an investigation into the activity of 1a-b in the presence of isocyanides (i.e.(t)BuNC), which resulted in isolation of Tp(Ph,Me)Ni(η(2-t)BuNC)CH2Ph (5a) and Tp(Ph,Me)Ni(η(2-t)BuNC)CH2Si(CH3)3 (5b). Similarly, reaction of 1a with OCS led to the isolation of a rare example of a Ni(i) carbonyl species Tp(Ph,Me)NiCO (6). Alternatively, complex 6 was also formed by exposure of 1a-b to an atmosphere of CO. Isolation of the intermediate species (Tp(Ph,Me)Ni(η(2)-CO)CH2TMS (7b) and Tp(Ph,Me)Ni(CO)(C(O)R, (8a-b) with R = Ph, TMS)) shed light on the formation of such species.
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Affiliation(s)
- Mark Abubekerov
- Department of Chemistry, University of California, Berkeley, CA 94720, USA.
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13
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Camp C, Grant LN, Bergman RG, Arnold J. Photo-activation of d(0) niobium imido azides: en route to nitrido complexes. Chem Commun (Camb) 2016; 52:5538-41. [PMID: 27033145 DOI: 10.1039/c6cc02081j] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report the synthesis and photo-reactivity of d(0) niobium imido azido complexes supported by β-diketiminate ligands, which leads to the unprecedented formation of nitrides through a photo-assisted intramolecular rearrangement. This provides a new entry to metal nitrides that does not require low-valent metal centers and is a rare example in which the metal-imido moiety in group 5 complexes participates in reactivity.
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Affiliation(s)
- Clément Camp
- C2P2 UMR 5265 CNRS, Université Lyon 1, ESCPE Lyon, 43 Bd du 11 Novembre 1918, F-69616 Villeurbanne, France
| | - Lauren N Grant
- Department of Chemistry, University of California, Berkeley, California 94720, USA.
| | - Robert G Bergman
- Department of Chemistry, University of California, Berkeley, California 94720, USA.
| | - John Arnold
- Department of Chemistry, University of California, Berkeley, California 94720, USA.
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14
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Ziegler JA, Bergman RG, Arnold J. Unusual κ1 coordination of a β-diketiminate ligand in niobium complexes. Dalton Trans 2016; 45:12661-8. [PMID: 27461382 DOI: 10.1039/c6dt02373h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Reaction of (BDI)Nb(N(t)Bu)Cl2py with NaCp results in the κ(1)-coordination of the BDI ligand in the complex (κ(1)-N,BDI)CpNb(N(t)Bu)Cl (2). Via chloride abstraction from 2, we develop synthetic routes to structurally analogous cationic and Nb(IV) pseudo-four coordinate complexes where the BDI ligand returns to the κ(2)-coordination mode. We compare these to our previously reported tetrahedral niobium bis(imido) complexes to investigate the effects of the Cp ligand on the properties of Nb-BDI-imido systems. Substitution of the chloride in 2 with a hydride also causes return to bidentate binding of the BDI ligand. The X-ray crystal structures of these complexes have been determined, and the structural parameters reflecting the consequences of the electronic differences are discussed.
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Affiliation(s)
- Jessica A Ziegler
- Department of Chemistry, University of California, Berkeley, California 94720, USA.
| | - Robert G Bergman
- Department of Chemistry, University of California, Berkeley, California 94720, USA.
| | - John Arnold
- Department of Chemistry, University of California, Berkeley, California 94720, USA.
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15
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16
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Hohloch S, Kriegel BM, Bergman RG, Arnold J. Group 5 chemistry supported by β-diketiminate ligands. Dalton Trans 2016; 45:15725-15745. [DOI: 10.1039/c6dt01770c] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
β-Diketiminate (BDI) ligands are widely used supporting ligands in modern organometallic chemistry and are capable of stabilizing various metal complexes in multiple oxidation states and coordination environments.
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Affiliation(s)
| | | | | | - John Arnold
- Department of Chemistry
- University of California
- Berkeley
- USA
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17
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Camp C, Arnold J. On the non-innocence of “Nacnacs”: ligand-based reactivity in β-diketiminate supported coordination compounds. Dalton Trans 2016; 45:14462-98. [DOI: 10.1039/c6dt02013e] [Citation(s) in RCA: 133] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
While β-diketiminate (BDI or ‘nacnac’) ligands have been widely adopted to stabilize a wide range of metal ions in multiple oxidation states and coordination numbers, in several occurrences these ligands do not behave as spectators and participate in reactivity.
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Affiliation(s)
- Clément Camp
- Univ Lyon
- CNRS, ESCPE Lyon
- Université Claude Bernard Lyon 1
- C2P2 UMR 5265
- F-69616 Villeurbanne
| | - John Arnold
- Department of Chemistry
- University of California
- Berkeley
- USA
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18
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Kriegel BM, Bergman RG, Arnold J. Nitrene Metathesis and Catalytic Nitrene Transfer Promoted by Niobium Bis(imido) Complexes. J Am Chem Soc 2015; 138:52-5. [DOI: 10.1021/jacs.5b11287] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Benjamin M. Kriegel
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Robert G. Bergman
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - John Arnold
- Department of Chemistry, University of California, Berkeley, California 94720, United States
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19
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Nechayev M, Gianetti TL, Bergman RG, Arnold J. C–F sp2 bond functionalization mediated by niobium complexes. Dalton Trans 2015. [DOI: 10.1039/c5dt02082d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The functionalization of fluorobenzene is described via insertion of isocyanide after the oxidative addition of the C–F bond.
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Affiliation(s)
| | | | | | - John Arnold
- Department of Chemistry
- University of California
- Berkeley
- USA
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