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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Lawford KG, Land MA, Goodwin E, Robertson KN, Barry ST. Synthesis, Characterization, and Single-Crystal X-ray Structures of Refractory Metal Compounds as Precursors for the Single-Source Chemical Vapor Deposition of Metal Nitrides. Inorg Chem 2023; 62:21061-21073. [PMID: 38064637 DOI: 10.1021/acs.inorgchem.3c02841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2023]
Abstract
The chemical vapor deposition of refractory metal nitrides requires volatile precursors and has previously been achieved by using metal complexes containing a variety of imide ligands. Recently, the 1,4-di-tert-butyl-1,3-diazabutadiene (DAD) adduct of bis(tert-butylimide)dichloridemolybdenum(VI) was shown to be an excellent precursor for the single-source CVD of Mo2N thin films. Leveraging the success of this work, we prepared chromium and tungsten compounds with the same framework. Additionally, the framework has been modified slightly to allow the isolation of mono(tert-butylimide)trichloride complexes of vanadium, niobium, tantalum, and molybdenum(V) to extend the search for new vapor-phase precursors. These compounds were all fully characterized using the standard methods of multinuclear magnetic resonance spectroscopy, combustion analysis, and single-crystal X-ray diffraction. Their thermal properties were determined by using thermogravimetric analysis and differential scanning colorimetry to assess their utility as vapor-phase precursors. Finally, preliminary deposition studies were carried out to investigate their potential as single-source CVD precursors.
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Affiliation(s)
- Kieran G Lawford
- Department of Chemistry, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada
| | - Michael A Land
- Department of Chemistry, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada
| | - Eden Goodwin
- Department of Chemistry, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada
| | - Katherine N Robertson
- Department of Chemistry, Saint Mary's University, 923 Robie Street, Halifax, Nova Scotia B3H 3C3, Canada
| | - Seán T Barry
- Department of Chemistry, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada
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3
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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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4
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Mononuclear Oxidovanadium(IV) Complexes with BIAN Ligands: Synthesis and Catalytic Activity in the Oxidation of Hydrocarbons and Alcohols with Peroxides. Catalysts 2022. [DOI: 10.3390/catal12101168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Reactions of VCl3 with 1,2-Bis[(4-methylphenyl)imino]acenaphthene (4-Me-C6H4-bian) or 1,2-Bis[(2-methylphenyl)imino]acenaphthene (2-Me-C6H4-bian) in air lead to the formation of [VOCl2(R-bian)(H2O)] (R = 4-Me-C6H4 (1), 2-Me-C6H4 (2)). Thes complexes were characterized by IR and EPR spectroscopy as well as elemental analysis. Complexes 1 and 2 have high catalytic activity in the oxidation of hydrocarbons with hydrogen peroxide and alcohols with tert-butyl hydroperoxide in acetonitrile at 50 °С. The product yields are up to 40% for cyclohexane. Of particular importance is the addition of 2-pyrazinecarboxylic acid (PCA) as a co-catalyst. Oxidation proceeds mainly with the participation of free hydroxyl radicals, as evidenced by taking into account the regio- and bond-selectivity in the oxidation of n-heptane and methylcyclohexane, as well as the dependence of the reaction rate on the initial concentration of cyclohexane.
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5
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Bernauer J, Pölker J, Jacobi von Wangelin A. Redox-active BIAN-based Diimine Ligands in Metal-Catalyzed Small Molecule Syntheses. ChemCatChem 2022; 14:e202101182. [PMID: 35875682 PMCID: PMC9298226 DOI: 10.1002/cctc.202101182] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 09/24/2021] [Indexed: 12/14/2022]
Abstract
α-Diimine ligands have significantly shaped the coordination chemistry of most transition metal complexes. Among them, bis(imino)acenaphthene ligands (BIANs) have recently been matured to great versatility and applicability to catalytic reactions. Besides variations of the ligand periphery, the great versatility of BIAN ligands resides within their ability to undergo facile electronic manipulations. This review highlights key aspects of BIAN ligands in metal complexes and summarizes recent contributions of metal-BIAN catalysts to syntheses of small and functionalized organic molecules.
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Affiliation(s)
- Josef Bernauer
- Department of ChemistryUniversity of HamburgMartin Luther King Pl 620146HamburgGermany
| | - Jennifer Pölker
- Department of ChemistryUniversity of HamburgMartin Luther King Pl 620146HamburgGermany
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6
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Reactions of Dihaloboranes with Electron-Rich 1,4-Bis(trimethylsilyl)-1,4-diaza-2,5-cyclohexadienes. Molecules 2020; 25:molecules25122875. [PMID: 32580464 PMCID: PMC7356994 DOI: 10.3390/molecules25122875] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 06/14/2020] [Accepted: 06/16/2020] [Indexed: 11/16/2022] Open
Abstract
The reactions of electron-rich organosilicon compounds 1,4-bis(trimethylsilyl)-1,4-diaza-2,5-cyclohexadiene (1), 2,3,5,6-tetramethyl-1,4-bis(trimethylsilyl)-1,4-diaza-2,5-cyclohexadiene (2), and 1,1'-bis(trimethylsilyl)-1,1'-dihydro-4,4'-bipyridine (12) with B-amino and B-aryl dihaloboranes afforded a series of novel B=N-bond-containing compounds 3-11 and 13. The B=N rotational barriers of 7 (>71.56 kJ/mol), 10 (58.79 kJ/mol), and 13 (58.65 kJ/mol) were determined by variable-temperature 1H-NMR spectroscopy, thus reflecting different degrees of B=N double bond character in the corresponding compounds. In addition, ring external olefin isomers 11 were obtained by a reaction between 2 and DurBBr2. All obtained B=N-containing products were characterized by multinuclear NMR spectroscopy. Compounds 5, 9, 10a, 11, and 13a were also characterized by single-crystal X-ray diffraction analysis.
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7
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Mashima K. Redox-Active α-Diimine Complexes of Early Transition Metals: From Bonding to Catalysis. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2020. [DOI: 10.1246/bcsj.20200056] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Kazushi Mashima
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
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8
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Ikeda H, Nishi K, Tsurugi H, Mashima K. Chromium-catalyzed cyclopropanation of alkenes with bromoform in the presence of 2,3,5,6-tetramethyl-1,4-bis(trimethylsilyl)-1,4-dihydropyrazine. Chem Sci 2020; 11:3604-3609. [PMID: 34094048 PMCID: PMC8152687 DOI: 10.1039/d0sc00964d] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 03/04/2020] [Indexed: 12/20/2022] Open
Abstract
Chromium-catalyzed cyclopropanation of alkenes with bromoform was achieved to produce the corresponding bromocyclopropanes. In this catalytic cyclopropanation, an organosilicon reductant, 2,3,5,6-tetramethyl-1,4-bis(trimethylsilyl)-1,4-dihydropyrazine (1a), was indispensable for reducing CrCl3(thf)3 to CrCl2(thf)3, as well as for in situ generation of (bromomethylidene)chromium(iii) species from (dibromomethyl)chromium(iii) species. The (bromomethylidene)chromium(iii) species are proposed to react spontaneously with alkenes to give the corresponding bromocyclopropanes. This catalytic cyclopropanation was applied to various olefinic substrates, such as allyl ethers, allyl esters, terminal alkenes, and cyclic alkenes.
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Affiliation(s)
- Hideaki Ikeda
- Department of Chemistry, Graduate School of Engineering Science, Osaka University Toyonaka Osaka 560-8531 Japan
| | - Kohei Nishi
- 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
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9
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Parker BF, Hosoya H, Arnold J, Tsurugi H, Mashima K. α-Diimine-Niobium Complex-Catalyzed Deoxychlorination of Benzyl Ethers with Silicon Tetrachloride. Inorg Chem 2019; 58:12825-12831. [PMID: 31498599 DOI: 10.1021/acs.inorgchem.9b01784] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
α-Diimine niobium complexes serve as catalysts for deoxygenation of benzyl ethers by silicon tetrachloride (SiCl4) to cleanly give two equivalents of the corresponding benzyl chlorides, where SiCl4 has the dual function of oxygen scavenger and chloride source with the formation of a silyl ether or silica as the only byproduct. The reaction mechanism has two successive trans-etherification steps that are mediated by the niobium catalyst, first forming one equivalent of benzyl chloride along with the corresponding silyl ether intermediate that undergoes the same reaction pathway to give the second equivalent of benzyl chloride and silyl ether.
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Affiliation(s)
- 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
| | - Hiromu Hosoya
- Department of Chemistry, Graduate School of Engineering Science , Osaka University , Toyonaka , Osaka 560-8531 , Japan
| | - John Arnold
- Department of Chemistry , University of California , Berkeley , California 94720 , United States
| | - 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
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10
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Beagan DM, Huerfano IJ, Polezhaev AV, Caulton KG. Reductive Silylation Using a Bis-silylated Diaza-2,5-cyclohexadiene. Chemistry 2019; 25:8105-8111. [PMID: 30994211 DOI: 10.1002/chem.201900879] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Indexed: 11/06/2022]
Abstract
1,4-Bis(trimethylsilyl)-1,4-diaza-2,5-cyclohexadiene, 1, was tested as a reagent for the reductive silylation of various unsaturated functionalities, including N-heterocycles, quinones, and other redox-active moieties in addition to deoxygenation of main group oxides. Whereas most reactions tested are thermodynamically favorable, based on DFT calculations, a few do not occur, perhaps giving limited insight on the mechanism of this very attractive reductive process. Of note, reductive silylation reactions show a strong solvent dependence where a polar solvent facilitates conversions.
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Affiliation(s)
- Daniel M Beagan
- Department of Chemistry, Indiana University, Bloomington, IN, 47405, USA
| | - I J Huerfano
- Department of Chemistry, Indiana University, Bloomington, IN, 47405, USA
| | | | - Kenneth G Caulton
- Department of Chemistry, Indiana University, Bloomington, IN, 47405, USA
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11
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Quintal S, Pires da Silva MJ, Martins SRM, Sales R, Félix V, Drew MGB, Meireles M, Mourato AC, Nunes CD, Saraiva MS, Machuqueiro M, Calhorda MJ. Molybdenum(ii) complexes with p-substituted BIAN ligands: synthesis, characterization, biological activity and computational study. Dalton Trans 2019; 48:8449-8463. [PMID: 31116201 DOI: 10.1039/c9dt00469f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
New complexes [Mo(η3-C3H5)X(CO)2(4-Y-BIAN)] (4-Y-BIAN = bis(4-Y-phenyl)-acenaphthenequinonediimine), with X = Br and Y = H, Me, OMe, COOH and X = Cl, Y = OMe, as well as the cation with X = NCMe and Y = OMe were synthesized, expanding the scope of this family. Two single crystal X-ray structures (X = Br, Y = Me, OMe) display a less symmetric arrangement (axial isomer), where one N donor atom is trans to the allyl group and the second to one CO. DFT studies showed similar energies for the two possible isomers of the complexes, with a very small preference for the observed axial isomer. The HOMO of the complexes is localized in the metal and the HOMO-1 of the oxidized species has a contribution from the BIAN ligand, while the LUMO is fully localized in BIAN. Electrochemical studies showed one process corresponding to the oxidation of Mo(ii) to Mo(iii) for complexes with X = Br, Y = H, Me, and two oxidation reactions for those with X = Br, Y = Cl, OMe, while the COOH derivative exhibited no oxidation wave. The antitumor effect of the complexes with X = Br was tested in cancer lines, and the H and OMe complexes were particularly active, with EC50 values below 8 μM in HeLa cell lines. The DNA binding constants determined by titration experiments were comparable with those of doxorubicin and ethidium bromide, suggesting a mechanism of action based on intercalation in DNA.
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Affiliation(s)
- Susana Quintal
- Centro de Química e Bioquímica, DQB, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal.
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12
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Tsurugi H, Mashima K. Salt-Free Reduction of Transition Metal Complexes by Bis(trimethylsilyl)cyclohexadiene, -dihydropyrazine, and -4,4'-bipyridinylidene Derivatives. Acc Chem Res 2019; 52:769-779. [PMID: 30794373 DOI: 10.1021/acs.accounts.8b00638] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Chemical reduction of transition metals provides the corresponding low-valent transition metal species as a key step for generating catalytically active species in metal-assisted organic transformations and is a fundamental unit reaction for preparing organometallic complexes. A variety of metal-based reductants, such as metal powders and organometallic reagents of alkali and alkaline-earth metals, have been developed to date to access low-valent metal species. During the reduction, however, reductant-derived metal salts are formed as reaction waste, some of which often interact with the reactive low-valent metal center, thereby disrupting the catalytic performance and hampering the isolation of organometallic complexes as a result of salt coordination to the coordinatively unsaturated vacant and active sites and the formation of thermally unstable ate complexes. In this Account, we emphasize the synthetic utility and versatility of organic reductants containing two trimethylsilyl groups, i.e., 1,4-bis(trimethylsilyl)cyclohexa-2,5-diene (1a) and its methyl derivative (1b), 1,4-bis(trimethylsilyl)dihydropyrazine (2a) and its dimethyl (2b) and tetramethyl (2c) derivatives, and 1,1'-bis(trimethylsilyl)-4,4'-bipyridinylidene (3), leading to the reduction of various kinds of metal compounds in a salt-free fashion by release of two electrons together with the coproduction of easily removable (hetero)aromatics and trimethylsilyl derivatives from these organic reductants 1-3. When homoleptic chlorides of group 5 and 6 metals are treated with 1a and 1b, in situ-generated highly reactive low-valent metal species react with redox-active molecules such as ethylene, α-diimines, and α-diketones to produce metallacyclopentane, (ene-diamido)metal, and (ene-diolato)metal complexes, respectively. The advantage of the salt-free protocol is further exemplified in the low-valent titanocene-catalyzed Reformatsky-type reaction when 2c is used as a reductant: the yield of the product using the organosilicon reductant is higher than that when manganese powder is used as the reductant for the catalytic Reformatsky-type reaction of ethyl 2-bromoisobutyrate and its derivatives with various aldehydes. Moreover, when halides, carboxylates, and acetylacetonate compounds of late transition metals and main-group elements are treated with the organosilicon reductant 2c, metal(0) particles are smoothly precipitated under mild conditions. Among them, metallic nickel(0) nanoparticles are applicable to reductive biaryl formation and reductive cross-coupling of aryl halides/aryl aldehydes. In addition, reduction of the heterogeneous catalysts on a solid supporting matrix was also achieved by this salt-free reduction method; volatile byproducts are easily removed from the catalyst surface without suppressing the catalytic performance. Thus, the salt-free reduction strategy is a very powerful synthetic method that can be extended to various metals throughout the periodic table.
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Affiliation(s)
- 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
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13
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Messinis AM, Wright WRH, Batsanov AS, Howard JAK, Hanton MJ, Dyer PW. Exploration of Homogeneous Ethylene Dimerization Mediated by Tungsten Mono(imido) Complexes. ACS Catal 2018. [DOI: 10.1021/acscatal.8b02201] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
| | | | | | | | - Martin J. Hanton
- Sasol Technology UK Limited, Purdie Building, North Haugh, Saint Andrews, Fife, KY16 9ST, United Kingdom
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14
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Haeri HH, Duraisamy R, Harmgarth N, Liebing P, Lorenz V, Hinderberger D, Edelmann FT. Electronic and Geometric Structures of Paramagnetic Diazadiene Complexes of Lithium and Sodium. ChemistryOpen 2018; 7:701-708. [PMID: 30202705 PMCID: PMC6123648 DOI: 10.1002/open.201800114] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Indexed: 11/08/2022] Open
Abstract
The electronic and molecular structures of the lithium and sodium complexes of 1,4-bis(2,6-diisopropylphenyl)-2,3-dimethyl-1,4-diazabutadiene (Me2DADDipp) were fully characterized by using a multi-frequency electron paramagnetic resonance (EPR) spectroscopy approach and crystallography, together with density functional theory (DFT) calculations. EPR measurements, using T1 relaxation-time-filtered pulse EPR spectroscopy, revealed the diagonal elements of the A and g tensors for the metal and ligand sites. It was found that the central metals in the lithium complexes had sizable contributions to the SOMO, whereas this contribution was less strongly observed for the sodium complex. Such strong contributions were attributed to structural specifications (e.g. geometrical data and atomic size) rather than electronic effects.
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Affiliation(s)
- Haleh H. Haeri
- Institute of ChemistryMartin Luther University Halle-WittenbergVon-Danckelmann-Platz 406120HalleGermany
| | - Ramesh Duraisamy
- Institute of ChemistryOtto-von-Guericke UniversityMagdeburg39106Germany
| | - Nicole Harmgarth
- Institute of ChemistryOtto-von-Guericke UniversityMagdeburg39106Germany
| | - Phil Liebing
- Laboratory for Inorganic ChemistryETH ZürichVladimir-Prelog-Weg 28093ZürichSwitzerland
| | - Volker Lorenz
- Institute of ChemistryOtto-von-Guericke UniversityMagdeburg39106Germany
| | - Dariush Hinderberger
- Institute of ChemistryMartin Luther University Halle-WittenbergVon-Danckelmann-Platz 406120HalleGermany
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15
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Bartalucci N, Bortoluzzi M, Zacchini S, Pampaloni G, Marchetti F. Activation of CN bonds by high-valent group 6 metal chlorides, including the conversion of an α-diimine into a functionalized imidazolium. NEW J CHEM 2018. [DOI: 10.1039/c8nj00846a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The direct interactions of WCl6and MoCl5with α-diimines (and also a carbodiimide in the case of MoCl5) have been explored, leading to unusual reaction pathways.
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Affiliation(s)
- Niccolò Bartalucci
- Università di Pisa
- Dipartimento di Chimica e Chimica Industriale
- I-56124 Pisa
- Italy
- CIRCC
| | - Marco Bortoluzzi
- CIRCC
- I-70126 Bari
- Italy
- Università Ca’ Foscari Venezia
- Dipartimento di Scienze Molecolari e Nanosistemi
| | - Stefano Zacchini
- CIRCC
- I-70126 Bari
- Italy
- Università di Bologna
- Dipartimento di Chimica Industriale “Toso Montanari”
| | - Guido Pampaloni
- Università di Pisa
- Dipartimento di Chimica e Chimica Industriale
- I-56124 Pisa
- Italy
- CIRCC
| | - Fabio Marchetti
- Università di Pisa
- Dipartimento di Chimica e Chimica Industriale
- I-56124 Pisa
- Italy
- CIRCC
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16
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Ikeda H, Nishi K, Tsurugi H, Mashima K. Metathesis cleavage of an NN bond in benzo[c]cinnolines and azobenzenes by triply-bonded ditungsten complexes. Chem Commun (Camb) 2018; 54:3709-3711. [PMID: 29441373 DOI: 10.1039/c7cc08570b] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A metathesis reaction of a WW bond and an NN bond was observed by reacting a W–W triply-bonded W(iii)2 complex, (tBuO)3WW(OtBu)3 (1), with benzo[c]cinnoline derivatives to form biphenyl-linked dinuclear (imido)tungsten complexes 2–4.
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Affiliation(s)
- Hideaki Ikeda
- Department of Chemistry
- Graduate School of Engineering Science
- Osaka University
- Toyonaka
- Japan
| | - Kohei Nishi
- Department of Chemistry
- Graduate School of Engineering Science
- Osaka University
- Toyonaka
- Japan
| | - Hayato Tsurugi
- Department of Chemistry
- Graduate School of Engineering Science
- Osaka University
- Toyonaka
- Japan
| | - Kazushi Mashima
- Department of Chemistry
- Graduate School of Engineering Science
- Osaka University
- Toyonaka
- Japan
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17
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Bartalucci N, Bortoluzzi M, Pampaloni G, Pinzino C, Zacchini S, Marchetti F. Stable coordination complexes of α-diimines with Nb(v) and Ta(v) halides. Dalton Trans 2018; 47:3346-3355. [DOI: 10.1039/c8dt00122g] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Uncommon coordination compounds of high valent transition metal halides with N-aryl α-diimines have been obtained, without the need for reducing agents to quench the activation power of the metal centre.
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Affiliation(s)
- Niccolò Bartalucci
- Università di Pisa
- Dipartimento di Chimica e Chimica Industriale
- I-56124 Pisa
- Italy
- CIRCC
| | - Marco Bortoluzzi
- CIRCC
- I-70126 Bari
- Italy
- Università Ca’ Foscari Venezia
- Dipartimento di Scienze Molecolari e Nanosistemi
| | - Guido Pampaloni
- Università di Pisa
- Dipartimento di Chimica e Chimica Industriale
- I-56124 Pisa
- Italy
- CIRCC
| | | | - Stefano Zacchini
- CIRCC
- I-70126 Bari
- Italy
- Università di Bologna
- Dipartimento di Chimica Industriale “Toso Montanari”
| | - Fabio Marchetti
- Università di Pisa
- Dipartimento di Chimica e Chimica Industriale
- I-56124 Pisa
- Italy
- CIRCC
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18
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Yang H, Zhao Y, Liu B, Su JH, Fedushkin IL, Wu B, Yang XJ. Noninnocent ligands: heteroleptic nickel complexes with α-diimine and 1,2-diketone derivatives. Dalton Trans 2017; 46:7857-7865. [PMID: 28598473 DOI: 10.1039/c7dt00455a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reaction of the Ni-Ni-bonded compound [(NiIL˙-)2] (1, L = [(2,6-iPr2C6H3)NC(Me)]2) with various 1,2-diketones afforded a series of heteroleptic complexes: [LNi(PhC(O)-C(O)Ph)] (2), [LNi(PhC(O)-C(O)Me)] (3), [LNi(3,5-tBu2C6H2O2)] (4), and [(LNi){μ-η2,η2-(MeC(O)-C(O)Me)}(NiL)] (5). Furthermore, the complex [Na(Et2O)][LNi{PhC(O)-C(O)Ph}] (6) was obtained by the reduction of 2 with 1.0 equiv. of Na metal. These complexes, which contain three potential redox-active centers, nickel and both α-diimine and 1,2-diketone ligands, were characterized by X-ray crystallography, NMR, EPR, and UV-vis-NIR spectra, magnetic susceptibility measurements, and DFT computations to elucidate their electronic structures.
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Affiliation(s)
- Hong Yang
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an 710069, China.
| | - Yanxia Zhao
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an 710069, China.
| | - Bin Liu
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an 710069, China.
| | - Ji-Hu Su
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Igor L Fedushkin
- G. A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Tropinina 49, 603950, Nizhny Novgorod GSP-445, Russia
| | - Biao Wu
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an 710069, China.
| | - Xiao-Juan Yang
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an 710069, China.
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19
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Nishiyama H, Ikeda H, Saito T, Kriegel B, Tsurugi H, Arnold J, Mashima K. Structural and Electronic Noninnocence of α-Diimine Ligands on Niobium for Reductive C-Cl Bond Activation and Catalytic Radical Addition Reactions. J Am Chem Soc 2017; 139:6494-6505. [PMID: 28409626 DOI: 10.1021/jacs.7b02710] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A d0 niobium(V) complex, NbCl3(α-diimine) (1a), supported by a dianionic redox-active N,N'-bis(2,6-diisopropylphenyl)-1,4-diaza-2,3-dimethyl-1,3-butadiene (α-diimine) ligand (ene-diamido ligand) served as a catalyst for radical addition reactions of CCl4 to α-olefins and cyclic alkenes, selectively affording 1:1 radical addition products in a regioselective manner. During the catalytic reaction, the α-diimine ligand smoothly released and stored an electron to control the oxidation state of the niobium center by changing between an η4-(σ2,π) coordination mode with a folded MN2C2 metallacycle and a κ2-(N,N') coordination mode with a planar MN2C2 metallacycle. Kinetic studies of the catalytic reaction elucidated the reaction order in the catalytic cycle: the radical addition reaction rate obeyed first-order kinetics that were dependent on the concentrations of the catalyst, styrene, and CCl4, while a saturation effect was observed at a high CCl4 concentration. In the presence of excess amounts of styrene, styrene coordinated in an η2-olefinic manner to the niobium center to decrease the reaction rate. No observation of oligomers or polymers of styrene and high stereoselectivity for the radical addition reaction of CCl4 to cyclopentene suggested that the C-C bond formation proceeded inside the coordination sphere of niobium, which was in good accordance with the negative entropy value of the radical addition reaction. Furthermore, reaction of 1a with (bromomethyl)cyclopropane confirmed that both the C-Br bond activation and formation proceeded on the α-diimine-coordinated niobium center during transformation of the cyclopropylmethyl radical to a homoallyl radical. With regard to the reaction mechanism, we detected and isolated NbCl4(α-diimine) (6a) as a transient one-electron oxidized species of 1a during reductive cleavage of the C-X bonds; in addition, the monoanionic α-diimine ligand of 6a adopted a monoanionic canonical form with selective one-electron oxidation of the dianionic ene-diamido form of the ligand in 1a.
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Affiliation(s)
- Haruka Nishiyama
- Department of Chemistry, Graduate School of Engineering Science, Osaka University , Toyonaka, Osaka, 5608531, Japan
| | - Hideaki Ikeda
- Department of Chemistry, Graduate School of Engineering Science, Osaka University , Toyonaka, Osaka, 5608531, Japan
| | - Teruhiko Saito
- Department of Chemistry, Graduate School of Engineering Science, Osaka University , Toyonaka, Osaka, 5608531, Japan
| | - Benjamin Kriegel
- Department of Chemistry, Graduate School of Engineering Science, Osaka University , Toyonaka, Osaka, 5608531, Japan
| | - Hayato Tsurugi
- Department of Chemistry, Graduate School of Engineering Science, Osaka University , Toyonaka, Osaka, 5608531, Japan
| | - John Arnold
- Department of Chemistry, University of California , Berkeley, California 94720-1460, United States
| | - Kazushi Mashima
- Department of Chemistry, Graduate School of Engineering Science, Osaka University , Toyonaka, Osaka, 5608531, Japan
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20
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Yamamoto K, Higashida K, Nagae H, Tsurugi H, Mashima K. Synthesis and Characterization of Heterobimetallic Tantalum-Rhodium and Tantalum-Iridium Complexes Connected by a Tantalacyclopentadiene Fragment. Helv Chim Acta 2016. [DOI: 10.1002/hlca.201600180] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Keishi Yamamoto
- Department of Chemistry; Graduate School of Engineering Science; Osaka University; Toyonaka Osaka 560-8531 Japan
| | - Kosuke Higashida
- Department of Chemistry; Graduate School of Engineering Science; Osaka University; Toyonaka Osaka 560-8531 Japan
| | - Haruki Nagae
- 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
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