51
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Kunishita A, Gianetti TL, Arnold J. Structures, Physicochemical Properties, and Reactivities of Cobalt(II) Complexes Supported by a Homoscorpionate (Tris(pyrazolyl)borate) Ligand TpPh,Me. Organometallics 2011. [DOI: 10.1021/om200973x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Atsushi Kunishita
- Department of Chemistry, University of California, Berkeley, California 94720-1460, United
States
| | - Thomas L. Gianetti
- Department of Chemistry, University of California, Berkeley, California 94720-1460, United
States
| | - John Arnold
- Department of Chemistry, University of California, Berkeley, California 94720-1460, United
States
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52
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Danopoulos AA, Braunstein P, Stylianides N, Wesolek M. Aminolysis of Bis[bis(trimethylsilyl)amido]iron and -cobalt as a Versatile Route to N-Heterocyclic Carbene Complexes. Organometallics 2011. [DOI: 10.1021/om200951m] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Andreas A. Danopoulos
- Laboratoire
de Chimie de Coordination, Institut
de Chimie (UMR 7177 CNRS), Université de Strasbourg, 4 rue
Blaise Pascal, F-67081 Strasbourg Cedex, France
| | - Pierre Braunstein
- Laboratoire
de Chimie de Coordination, Institut
de Chimie (UMR 7177 CNRS), Université de Strasbourg, 4 rue
Blaise Pascal, F-67081 Strasbourg Cedex, France
| | - Neoklis Stylianides
- Laboratoire
de Chimie de Coordination, Institut
de Chimie (UMR 7177 CNRS), Université de Strasbourg, 4 rue
Blaise Pascal, F-67081 Strasbourg Cedex, France
| | - Marcel Wesolek
- Laboratoire
de Chimie de Coordination, Institut
de Chimie (UMR 7177 CNRS), Université de Strasbourg, 4 rue
Blaise Pascal, F-67081 Strasbourg Cedex, France
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53
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Theofanis PL, Goddard WA. Understanding β-Hydride Eliminations from Heteroatom Functional Groups. Organometallics 2011. [DOI: 10.1021/om200542w] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Patrick L. Theofanis
- Materials and Process Simulation Center, Beckman Institute (139-74), California Institute of Technology, Pasadena, California 91125, United States
| | - William A. Goddard
- Materials and Process Simulation Center, Beckman Institute (139-74), California Institute of Technology, Pasadena, California 91125, United States
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54
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Shrestha R, Weix DJ. Reductive conjugate addition of haloalkanes to enones to form silyl enol ethers. Org Lett 2011; 13:2766-9. [PMID: 21491901 DOI: 10.1021/ol200881v] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new method is presented for tandem reductive conjugate addition and silyl enol ether formation from cyclic and acyclic enones and enals in the presence of a Mn reductant, a Ni(terpyridine) catalyst, and a trialkylchlorosilane. The addition of secondary, tertiary, and hindered primary haloalkanes is demonstrated. Preliminary studies on the mechanism show that the intermediacy of L1(Ni)(η(3)-1-triethylsilyloxyalkenyl)X or in-situ-formed RMnX is unlikely.
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Affiliation(s)
- Ruja Shrestha
- Department of Chemistry, University of Rochester, Rochester, New York 14627-0216, United States
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55
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Wu B, Zhang J, Yun L, Fu X. Mechanistic comparison of β-H elimination, β-OH elimination, and nucleophilic displacement reactions of β-hydroxy alkyl rhodium porphyrin complexes. Dalton Trans 2011; 40:2213-7. [DOI: 10.1039/c0dt01146k] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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56
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Chen Q, Ilies L, Nakamura E. Cobalt-Catalyzed ortho-Alkylation of Secondary Benzamide with Alkyl Chloride through Directed C−H Bond Activation. J Am Chem Soc 2010; 133:428-9. [DOI: 10.1021/ja1099853] [Citation(s) in RCA: 235] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Quan Chen
- Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033
| | - Laurean Ilies
- Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033
| | - Eiichi Nakamura
- Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033
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57
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Jiang Y, Hess J, Fox T, Berke H. Rhenium Hydride/Boron Lewis Acid Cocatalysis of Alkene Hydrogenations: Activities Comparable to Those of Precious Metal Systems. J Am Chem Soc 2010; 132:18233-47. [DOI: 10.1021/ja107187r] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yanfeng Jiang
- Anorganisch-Chemisches Institut, Universität Zürich, Winterthurerstrasse 190, CH-8037 Zürich, Switzerland
| | - Jeannine Hess
- Anorganisch-Chemisches Institut, Universität Zürich, Winterthurerstrasse 190, CH-8037 Zürich, Switzerland
| | - Thomas Fox
- Anorganisch-Chemisches Institut, Universität Zürich, Winterthurerstrasse 190, CH-8037 Zürich, Switzerland
| | - Heinz Berke
- Anorganisch-Chemisches Institut, Universität Zürich, Winterthurerstrasse 190, CH-8037 Zürich, Switzerland
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58
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Breitenfeld J, Vechorkin O, Corminboeuf C, Scopelliti R, Hu X. Why Are (NN2)Ni Pincer Complexes Active for Alkyl−Alkyl Coupling: β-H Elimination Is Kinetically Accessible but Thermodynamically Uphill. Organometallics 2010. [DOI: 10.1021/om1007506] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jan Breitenfeld
- Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), SB-ISIC, Lausanne, CH 1015, Switzerland
| | - Oleg Vechorkin
- Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), SB-ISIC, Lausanne, CH 1015, Switzerland
| | - Clémence Corminboeuf
- Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), SB-ISIC, Lausanne, CH 1015, Switzerland
| | - Rosario Scopelliti
- Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), SB-ISIC, Lausanne, CH 1015, Switzerland
| | - Xile Hu
- Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), SB-ISIC, Lausanne, CH 1015, Switzerland
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59
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Ni C, Power PP. Methyl-Bridged Transition Metal Complexes (M = Cr−Fe) Supported by Bulky Terphenyl Ligands. Organometallics 2009. [DOI: 10.1021/om900724p] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Chengbao Ni
- Department of Chemistry, University of California, Davis, California 95616
| | - Philip P. Power
- Department of Chemistry, University of California, Davis, California 95616
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60
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Kleimark J, Hedström A, Larsson PF, Johansson C, Norrby PO. Mechanistic Investigation of Iron-Catalyzed Coupling Reactions. ChemCatChem 2009. [DOI: 10.1002/cctc.200900061] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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61
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Dugan TR, Holland PL. New Routes to Low-Coordinate Iron Hydride Complexes: The Binuclear Oxidative Addition of H(2). J Organomet Chem 2009; 694:nihms111237. [PMID: 20161197 PMCID: PMC2712230 DOI: 10.1016/j.jorganchem.2009.04.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The oxidative addition and reductive elimination reactions of H(2) on unsaturated transition-metal complexes are crucial in utilizing this important molecule. Both biological and man-made iron catalysts use iron to perform H(2) transformations, and highly unsaturated iron complexes in unusual geometries (tetrahedral and trigonal planar) are anticipated to give unusual or novel reactions. In this paper, two new synthetic routes to the low-coordinate iron hydride complex [L(tBu)Fe(μ-H)](2) are reported. Et(3)SiH was used as the hydride source in one route by taking advantage of the silaphilicity of the fluoride ligand in three-coordinate L(tBu)FeF. The other synthetic method proceeded through the binuclear oxidative addition of H(2) or D(2) to a putative Fe(I) intermediate. Deuteration was verified through reduction of an alkyne and release of the deuterated alkene product. Mössbauer spectra of [L(tBu)Fe(μ-H)](2) indicate that the samples are pure, and that the iron(II) centers are high-spin.
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Affiliation(s)
- Thomas R Dugan
- Department of Chemistry, University of Rochester, Rochester, NY 14627
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62
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Hong S, Hill LMR, Gupta AK, Naab BD, Gilroy JB, Hicks RG, Cramer CJ, Tolman WB. Effects of electron-deficient beta-diketiminate and formazan supporting ligands on copper(I)-mediated dioxygen activation. Inorg Chem 2009; 48:4514-23. [PMID: 19425614 DOI: 10.1021/ic9002466] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Copper(I) complexes of a diketiminate featuring CF(3) groups on the backbone and dimethylphenyl substituents (4) and a nitroformazan (5) were synthesized and shown by spectroscopy, X-ray crystallography, cyclic voltammetry, and theory to contain copper(I) sites electron-deficient relative to those supported by previously studied diketiminate complexes comprising alkyl or aryl backbone substituents. Despite their electron-poor nature, oxygenation of LCu(CH(3)CN) (L = 4 or 5) at room temperature yielded bis(hydroxo)dicopper(II) compounds and at -80 degrees C yielded bis(mu-oxo)dicopper complexes that were identified on the basis of UV-vis and resonance Raman spectroscopy, spectrophotometric titration results (2:1 Cu/O(2) ratio), electron paramagnetic resonance spectroscopy (silent), and density functional theory calculations. The bis(mu-oxo)dicopper complex supported by 5 exhibited unusual spectroscopic properties and decayed via a novel intermediate proposed to be a metallaverdazyl radical complex, findings that highlight the potential for the formazan ligand to exhibit "noninnocent" behavior.
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Affiliation(s)
- Sungjun Hong
- Department of Chemistry, Center for Metals in Biocatalysis, and Supercomputing Institute, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455, USA
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63
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Stabilization of dimethyliron(II) and methylcobalt(I) complexes bearing a hemilabile 2-benzoylpyridine ligand in octahedral and square-pyramidal coordination. Inorganica Chim Acta 2009. [DOI: 10.1016/j.ica.2008.09.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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64
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Camadanli S, Beck R, Flörke U, Klein HF. C−H Activation of Imines by Trimethylphosphine-Supported Iron Complexes and Their Reactivities. Organometallics 2009. [DOI: 10.1021/om800828j] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sebnem Camadanli
- Eduard-Zintl-Institut für Anorganische and Physikalische Chemie, Technische Universität Darmstadt, Petersenstrasse 18, Darmstadt, 64287, Germany, and Anorganische und Analytische Chemie, Universität Paderborn, Warburger Strasse 100, Paderborn, 33098, Germany
| | - Robert Beck
- Eduard-Zintl-Institut für Anorganische and Physikalische Chemie, Technische Universität Darmstadt, Petersenstrasse 18, Darmstadt, 64287, Germany, and Anorganische und Analytische Chemie, Universität Paderborn, Warburger Strasse 100, Paderborn, 33098, Germany
| | - Ulrich Flörke
- Eduard-Zintl-Institut für Anorganische and Physikalische Chemie, Technische Universität Darmstadt, Petersenstrasse 18, Darmstadt, 64287, Germany, and Anorganische und Analytische Chemie, Universität Paderborn, Warburger Strasse 100, Paderborn, 33098, Germany
| | - Hans-Friedrich Klein
- Eduard-Zintl-Institut für Anorganische and Physikalische Chemie, Technische Universität Darmstadt, Petersenstrasse 18, Darmstadt, 64287, Germany, and Anorganische und Analytische Chemie, Universität Paderborn, Warburger Strasse 100, Paderborn, 33098, Germany
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65
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Xue L, Ng KC, Lin Z. Theoretical studies on β-aryl elimination from Rh(i) complexes. Dalton Trans 2009:5841-50. [DOI: 10.1039/b902539a] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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66
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OSHIMA M, INOUE N. Theoretical Studies of the β-Hydrogen Elimination from π-Allyl Palladium Complexes. JOURNAL OF COMPUTER CHEMISTRY-JAPAN 2009. [DOI: 10.2477/jccj.h2031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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67
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Beck R, Zheng T, Sun H, Li X, Flörke U, Klein HF. C–H activation of diphenylphosphinoaryl-derivatives with dimethyltetrakis(trimethylphosphine)iron(II). J Organomet Chem 2008. [DOI: 10.1016/j.jorganchem.2008.08.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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68
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Trovitch RJ, Lobkovsky E, Chirik PJ. Bis(imino)pyridine Iron Alkyls Containing β-Hydrogens: Synthesis, Evaluation of Kinetic Stability, and Decomposition Pathways Involving Chelate Participation. J Am Chem Soc 2008; 130:11631-40. [PMID: 18686955 DOI: 10.1021/ja803296f] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ryan J. Trovitch
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York, 14853
| | - Emil Lobkovsky
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York, 14853
| | - Paul J. Chirik
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York, 14853
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69
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Holland PL. Electronic structure and reactivity of three-coordinate iron complexes. Acc Chem Res 2008; 41:905-14. [PMID: 18646779 DOI: 10.1021/ar700267b] [Citation(s) in RCA: 241] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[Reaction: see text]. The identity and oxidation state of the metal in a coordination compound are typically thought to be the most important determinants of its reactivity. However, the coordination number (the number of bonds to the metal) can be equally influential. This Account describes iron complexes with a coordination number of only three, which differ greatly from iron complexes with octahedral (six-coordinate) geometries with respect to their magnetism, electronic structure, preference for ligands, and reactivity. Three-coordinate complexes with a trigonal-planar geometry are accessible using bulky, anionic, bidentate ligands (beta-diketiminates) that steer a monodentate ligand into the plane of their two nitrogen donors. This strategy has led to a variety of three-coordinate iron complexes in which iron is in the +1, +2, and +3 oxidation states. Systematic studies on the electronic structures of these complexes have been useful in interpreting their properties. The iron ions are generally high spin, with singly occupied orbitals available for pi interactions with ligands. Trends in sigma-bonding show that iron(II) complexes favor electronegative ligands (O, N donors) over electropositive ligands (hydride). The combination of electrostatic sigma-bonding and the availability of pi-interactions stabilizes iron(II) fluoride and oxo complexes. The same factors destabilize iron(II) hydride complexes, which are reactive enough to add the hydrogen atom to unsaturated organic molecules and to take part in radical reactions. Iron(I) complexes use strong pi-backbonding to transfer charge from iron into coordinated alkynes and N 2, whereas iron(III) accepts charge from a pi-donating imido ligand. Though the imidoiron(III) complex is stabilized by pi-bonding in the trigonal-planar geometry, addition of pyridine as a fourth donor weakens the pi-bonding, which enables abstraction of H atoms from hydrocarbons. The unusual bonding and reactivity patterns of three-coordinate iron compounds may lead to new catalysts for oxidation and reduction reactions and may be used by nature in transient intermediates of nitrogenase enzymes.
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Affiliation(s)
- Patrick L. Holland
- Department of Chemistry, University of Rochester, Rochester, New York 14627
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70
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Liang LC, Chien PS, Lee PY. Phosphorus and Olefin Substituent Effects on the Insertion Chemistry of Nickel(II) Hydride Complexes Containing Amido Diphosphine Ligands. Organometallics 2008. [DOI: 10.1021/om701294a] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Lan-Chang Liang
- Department of Chemistry and Center for Nanoscience & Nanotechnology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Pin-Shu Chien
- Department of Chemistry and Center for Nanoscience & Nanotechnology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Pei-Ying Lee
- Department of Chemistry and Center for Nanoscience & Nanotechnology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
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71
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Yu Y, Sadique AR, Smith JM, Dugan TR, Cowley RE, Brennessel WW, Flaschenriem CJ, Bill E, Cundari TR, Holland PL. The reactivity patterns of low-coordinate iron-hydride complexes. J Am Chem Soc 2008; 130:6624-38. [PMID: 18444648 PMCID: PMC2474859 DOI: 10.1021/ja710669w] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
We report a survey of the reactivity of the first isolable iron-hydride complexes with a coordination number less than 5. The high-spin iron(II) complexes [(beta-diketiminate)Fe(mu-H)] 2 react rapidly with representative cyanide, isocyanide, alkyne, N 2, alkene, diazene, azide, CO 2, carbodiimide, and Brønsted acid containing substrates. The reaction outcomes fall into three categories: (1) addition of Fe-H across a multiple bond of the substrate, (2) reductive elimination of H 2 to form iron(I) products, and (3) protonation of the hydride to form iron(II) products. The products include imide, isocyanide, vinyl, alkyl, azide, triazenido, benzo[ c]cinnoline, amidinate, formate, and hydroxo complexes. These results expand the range of known bond transformations at iron complexes. Additionally, they give insight into the elementary transformations that may be possible at the iron-molybdenum cofactor of nitrogenases, which may have hydride ligands on high-spin, low-coordinate metal atoms.
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Affiliation(s)
- Ying Yu
- Department of Chemistry, University of Rochester, Rochester, New York, 14627
| | - Azwana R. Sadique
- Department of Chemistry, University of Rochester, Rochester, New York, 14627
| | - Jeremy M. Smith
- Department of Chemistry, University of Rochester, Rochester, New York, 14627
| | - Thomas R. Dugan
- Department of Chemistry, University of Rochester, Rochester, New York, 14627
| | - Ryan E. Cowley
- Department of Chemistry, University of Rochester, Rochester, New York, 14627
| | | | | | - Eckhard Bill
- Max-Planck-Institut für Bioanorganische Chemie, D-45470 Mülheim an der Ruhr, Germany
| | - Thomas R. Cundari
- Department of Chemistry and Center for Advanced Scientific Computing and Modeling (CASCaM), University of North Texas, Denton, Texas, 76203
| | - Patrick L. Holland
- Department of Chemistry, University of Rochester, Rochester, New York, 14627
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72
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Lam OP, Anthon C, Heinemann FW, O’Connor JM, Meyer K. Structural and Spectroscopic Characterization of a Charge-Separated Uranium Benzophenone Ketyl Radical Complex. J Am Chem Soc 2008; 130:6567-76. [DOI: 10.1021/ja801007q] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Oanh P. Lam
- Department of Chemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, and Department of Chemistry and Pharmacy, Inorganic Chemistry, University of Erlangen-Nürnberg, Egerlandstr. 1, D-91058 Erlangen, Germany
| | - Christian Anthon
- Department of Chemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, and Department of Chemistry and Pharmacy, Inorganic Chemistry, University of Erlangen-Nürnberg, Egerlandstr. 1, D-91058 Erlangen, Germany
| | - Frank W. Heinemann
- Department of Chemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, and Department of Chemistry and Pharmacy, Inorganic Chemistry, University of Erlangen-Nürnberg, Egerlandstr. 1, D-91058 Erlangen, Germany
| | - Joseph M. O’Connor
- Department of Chemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, and Department of Chemistry and Pharmacy, Inorganic Chemistry, University of Erlangen-Nürnberg, Egerlandstr. 1, D-91058 Erlangen, Germany
| | - Karsten Meyer
- Department of Chemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, and Department of Chemistry and Pharmacy, Inorganic Chemistry, University of Erlangen-Nürnberg, Egerlandstr. 1, D-91058 Erlangen, Germany
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73
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Sciarone TJJ, Nijhuis CA, Meetsma A, Hessen B. Neutral and Cationic Paramagnetic Amino-amidinate Iron(II) Complexes: 19F NMR Evidence for Interactions with Weakly Coordinating Anions. Organometallics 2008. [DOI: 10.1021/om701155b] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Timo J. J. Sciarone
- Center for Catalytic Olefin Polymerization, Stratingh Institute for Chemistry and Chemical Engineering, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands, and Dutch Polymer Institute (DPI), P.O. Box 906, 5600 AX Eindhoven, The Netherlands
| | - Christian A. Nijhuis
- Center for Catalytic Olefin Polymerization, Stratingh Institute for Chemistry and Chemical Engineering, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands, and Dutch Polymer Institute (DPI), P.O. Box 906, 5600 AX Eindhoven, The Netherlands
| | - Auke Meetsma
- Center for Catalytic Olefin Polymerization, Stratingh Institute for Chemistry and Chemical Engineering, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands, and Dutch Polymer Institute (DPI), P.O. Box 906, 5600 AX Eindhoven, The Netherlands
| | - Bart Hessen
- Center for Catalytic Olefin Polymerization, Stratingh Institute for Chemistry and Chemical Engineering, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands, and Dutch Polymer Institute (DPI), P.O. Box 906, 5600 AX Eindhoven, The Netherlands
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74
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Trovitch RJ, Lobkovsky E, Bill E, Chirik PJ. Functional Group Tolerance and Substrate Scope in Bis(imino)pyridine Iron Catalyzed Alkene Hydrogenation. Organometallics 2008. [DOI: 10.1021/om701091z] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ryan J. Trovitch
- Max-Planck Institute of Bioinorganic Chemistry, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany, and Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853
| | - Emil Lobkovsky
- Max-Planck Institute of Bioinorganic Chemistry, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany, and Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853
| | - Eckhard Bill
- Max-Planck Institute of Bioinorganic Chemistry, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany, and Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853
| | - Paul J. Chirik
- Max-Planck Institute of Bioinorganic Chemistry, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany, and Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853
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75
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Shirakawa E, Ikeda D, Yamaguchi S, Hayashi T. Fe-Cu cooperative catalysis in the isomerization of alkyl Grignard reagents. Chem Commun (Camb) 2008:1214-6. [PMID: 18309421 DOI: 10.1039/b717717h] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Alkyl Grignard reagents were found to be isomerized to more stable ones in high isomerization ratios (>99%) under cooperative catalysis by iron and copper, which promote isomerization of alkyl groups and transmetalation between Fe-Mg, respectively.
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Affiliation(s)
- Eiji Shirakawa
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan.
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76
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Pilz MF, Limberg C, Demeshko S, Meyer F, Ziemer B. Dinuclear iron complexes based on parallel β-diiminato binding sites: syntheses, structures and reaction with O2. Dalton Trans 2008:1917-23. [DOI: 10.1039/b715376g] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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77
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DeYonker NJ, Foley NA, Cundari TR, Gunnoe TB, Petersen JL. Combined Experimental and Computational Studies on the Nature of Aromatic C−H Activation by Octahedral Ruthenium(II) Complexes: Evidence for σ-Bond Metathesis from Hammett Studies. Organometallics 2007. [DOI: 10.1021/om7009057] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Nathan J. DeYonker
- Center for Advanced Scientific Computing and Modeling (CASCaM), Department of Chemistry, University of North Texas, Box 305070, Denton, Texas 76203-5070, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, and C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506-6045
| | - Nicholas A. Foley
- Center for Advanced Scientific Computing and Modeling (CASCaM), Department of Chemistry, University of North Texas, Box 305070, Denton, Texas 76203-5070, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, and C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506-6045
| | - Thomas R. Cundari
- Center for Advanced Scientific Computing and Modeling (CASCaM), Department of Chemistry, University of North Texas, Box 305070, Denton, Texas 76203-5070, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, and C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506-6045
| | - T. Brent Gunnoe
- Center for Advanced Scientific Computing and Modeling (CASCaM), Department of Chemistry, University of North Texas, Box 305070, Denton, Texas 76203-5070, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, and C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506-6045
| | - Jeffrey L. Petersen
- Center for Advanced Scientific Computing and Modeling (CASCaM), Department of Chemistry, University of North Texas, Box 305070, Denton, Texas 76203-5070, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, and C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506-6045
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78
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Computational study of methane functionalization by a multiply bonded, Ni-bis(phosphine) complex. J Organomet Chem 2007. [DOI: 10.1016/j.jorganchem.2007.05.042] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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79
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Stoian SA, Vela J, Smith JM, Sadique AR, Holland PL, Münck E, Bominaar EL. Mössbauer and computational study of an N2-bridged diiron diketiminate complex: parallel alignment of the iron spins by direct antiferromagnetic exchange with activated dinitrogen. J Am Chem Soc 2007; 128:10181-92. [PMID: 16881648 DOI: 10.1021/ja062051n] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This work reports Mössbauer and DFT studies of the diiron-N2 complex LMeFeNNFeLMe (L = beta-diketiminate), 1a. Complex 1a, formally diiron(I), has a system spin S = 3 with an isolated MS = +/-3 quasi-doublet as a ground state; the MS = +/-2 doublet is >100 cm-1 higher in energy. Complex 1a exhibits at 4.2 K a large, positive magnetic hyperfine field, Bint = +68.1 T, and an effective g value of 16 +/- 2 along the easy magnetization axis of the ground doublet; this value is significantly larger than the spin-only value (g = 12). These results have been rationalized by DFT calculations, which show that each Fe site donates significant electron density into the pi* orbitals of dinitrogen, resulting in a configuration best described as two high-spin FeII (Sa = Sb = 2) bridged by triplet N22- (Sc = 1). In this description the minority spin electron of each iron is accommodated by two nonbonding, closely spaced 3d orbitals, z2 and yz (z is perpendicular to the diketiminate planes, x is along the Fe...Fe vector). Spin-orbit coupling between these orbital states generates a large unquenched orbital momentum along the iron-iron vector. The S = 3 ground state of 1a results from strong antiferromagnetic direct exchange couplings of the Fe spins (Sa = Sb = 2) to the N22- spin (Sc = 1) and can be formulated as ((Sa,Sb)Sab = 4, Sc = 1), S = 3>; H = J(Sa + Sb).Sc with J approximately 3500 cm-1.
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Affiliation(s)
- Sebastian A Stoian
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, USA
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80
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Sadique AR, Gregory EA, Brennessel WW, Holland PL. Mechanistic insight into N=N cleavage by a low-coordinate iron(II) hydride complex. J Am Chem Soc 2007; 129:8112-21. [PMID: 17564444 PMCID: PMC2548314 DOI: 10.1021/ja069199r] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reaction pathways of high-spin iron hydride complexes are relevant to the mechanism of N2 reduction by nitrogenase, which has been postulated to involve paramagnetic iron-hydride species. However, almost all known iron hydrides are low-spin, diamagnetic Fe(II) compounds. We have demonstrated that the first high-spin iron hydride complex, LtBuFeH (LtBu = bulky beta-diketiminate), reacts with PhN=NPh to completely cleave the N-N double bond, giving LtBuFeNHPh. Here, we disclose a series of experiments that elucidate the mechanism of this reaction. Crossover and kinetic experiments rule out common nonradical mechanisms, and support a radical chain mechanism mediated by iron(I) species including a rare eta2-azobenzene complex. Therefore, this high-spin iron(II) hydride can break N-N bonds through both nonradical and radical insertion mechanisms, a special feature that enables novel reactivity.
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Affiliation(s)
- Azwana R. Sadique
- Department of Chemistry, University of Rochester, Rochester, New York 14627,
| | | | | | - Patrick L. Holland
- Department of Chemistry, University of Rochester, Rochester, New York 14627,
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81
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Yu Y, Brennessel WW, Holland PL. Borane B-C Bond Cleavage by a Low-Coordinate Iron Hydride Complex and N-N Bond Cleavage by the Hydridoborate Product. Organometallics 2007; 26:3217-3226. [PMID: 18725998 DOI: 10.1021/om7003805] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The iron(II) hydride dimers [L(R)Fe(μ-H)(2)FeL(R)] (L(Me) = 2,4-bis(2,6-diisopropylphenylimino) pent-3-yl; L(tBu) = 2,2,6,6-tetramethyl-3,5-bis(2,6-diisopropylphenylimino)hept-4-yl) abstract hydrocarbyl groups from BR'(3) (R' = Et, Ph) to give L(R)FeR' and L(R)Fe(μ-H)(2)BR'(2). Mechanistic studies with R = R' = Me are consistent with a process in which the hyride dimer opens one Fe-H bond, and subsequent B-H bond formation is concerted with dissociation of an Fe-H unit. Cleavage of boron-carbon bonds is likely to proceed at least in part from transient quaternary borate anions. In a separate bond-breaking reaction, L(Me)Fe(μ-H)(2)BEt(2) reacts with N(2)H(4) to eject H(2) from the bridging hydrides and cleave the N-N bond in the diaminoborate complex L(Me)Fe(μ-NH(2))(2)BEt(2). These novel bond-breaking reactions are facilitated by the low coordination number at the iron(II) center.
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Affiliation(s)
- Ying Yu
- Department of Chemistry, University of Rochester, NY 14627
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82
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Zhao P, Incarvito CD, Hartwig JF. Directly Observed Transmetalation from Boron to Rhodium. β-Aryl Elimination from Rh(I) Arylboronates and Diarylborinates. J Am Chem Soc 2007; 129:1876-7. [PMID: 17256944 DOI: 10.1021/ja068587q] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Pinjing Zhao
- Department of Chemistry, Yale University, P.O. Box 208107 New Haven, Connecticut 06520-8107, USA
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83
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Yliheikkilä K, Axenov K, Räisänen MT, Klinga M, Lankinen MP, Kettunen M, Leskelä M, Repo T. Manganese(II) Complexes in Ethene Polymerization. Organometallics 2007. [DOI: 10.1021/om0608105] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Katariina Yliheikkilä
- Department of Chemistry, Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55 (A. I. Virtasen aukio 1), University of Helsinki FIN-00014, Finland
| | - Kirill Axenov
- Department of Chemistry, Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55 (A. I. Virtasen aukio 1), University of Helsinki FIN-00014, Finland
| | - Minna T. Räisänen
- Department of Chemistry, Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55 (A. I. Virtasen aukio 1), University of Helsinki FIN-00014, Finland
| | - Martti Klinga
- Department of Chemistry, Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55 (A. I. Virtasen aukio 1), University of Helsinki FIN-00014, Finland
| | - Mikko P. Lankinen
- Department of Chemistry, Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55 (A. I. Virtasen aukio 1), University of Helsinki FIN-00014, Finland
| | - Mika Kettunen
- Department of Chemistry, Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55 (A. I. Virtasen aukio 1), University of Helsinki FIN-00014, Finland
| | - Markku Leskelä
- Department of Chemistry, Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55 (A. I. Virtasen aukio 1), University of Helsinki FIN-00014, Finland
| | - Timo Repo
- Department of Chemistry, Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55 (A. I. Virtasen aukio 1), University of Helsinki FIN-00014, Finland
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84
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Vela J, Cirera J, Smith JM, Lachicotte RJ, Flaschenriem CJ, Alvarez S, Holland PL. Quantitative geometric descriptions of the belt iron atoms of the iron-molybdenum cofactor of nitrogenase and synthetic iron(II) model complexes. Inorg Chem 2007; 46:60-71. [PMID: 17198413 PMCID: PMC2676240 DOI: 10.1021/ic0609148] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Six of the seven iron atoms in the iron-molybdenum cofactor of nitrogenase display an unusual geometry, which is distorted from the tetrahedral geometry that is most common in iron-sulfur clusters. This distortion pulls the iron along one C3 axis of the tetrahedron toward a trigonal pyramid. The trigonal pyramidal coordination geometry is rare in four-coordinate transition metal complexes. In order to document this geometry in a systematic fashion in iron(II) chemistry, we have synthesized a range of four-coordinate iron(II) complexes that vary from tetrahedral to trigonal pyramidal. Continuous shape measures are used for a quantitative comparison of the stereochemistry of the Fe atoms in the iron-molybdenum cofactor with those of the presently and previously reported model complexes, as well as with those in polynuclear iron-sulfur compounds. This understanding of the iron coordination geometry is expected to assist in the design of synthetic analogues for intermediates in the nitrogenase catalytic cycle.
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Affiliation(s)
- Javier Vela
- Department of Chemistry, University of Rochester, Rochester, New York 14627, USA
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85
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86
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Bai G, Wei P, Das A, Stephan DW. Mono- and Bimetallic (NacNac)Ni Cyclopentadienyl Complexes. Organometallics 2006. [DOI: 10.1021/om060757k] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Guangcai Bai
- Department of Chemistry & Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4
| | - Pingrong Wei
- Department of Chemistry & Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4
| | - Anjan Das
- Department of Chemistry & Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4
| | - Douglas W. Stephan
- Department of Chemistry & Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4
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87
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Smith JM, Sadique AR, Cundari TR, Rodgers KR, Lukat-Rodgers G, Lachicotte RJ, Flaschenriem CJ, Vela J, Holland PL. Studies of low-coordinate iron dinitrogen complexes. J Am Chem Soc 2006; 128:756-69. [PMID: 16417365 DOI: 10.1021/ja052707x] [Citation(s) in RCA: 266] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Understanding the interaction of N2 with iron is relevant to the iron catalyst used in the Haber process and to possible roles of the FeMoco active site of nitrogenase. The work reported here uses synthetic compounds to evaluate the extent of NN weakening in low-coordinate iron complexes with an FeNNFe core. The steric effects, oxidation level, presence of alkali metals, and coordination number of the iron atoms are varied, to gain insight into the factors that weaken the NN bond. Diiron complexes with a bridging N2 ligand, L(R)FeNNFeL(R) (L(R) = beta-diketiminate; R = Me, tBu), result from reduction of [L(R)FeCl]n under a dinitrogen atmosphere, and an iron(I) precursor of an N2 complex can be observed. X-ray crystallographic and resonance Raman data for L(R)FeNNFeL(R) show a reduction in the N-N bond order, and calculations (density functional and multireference) indicate that the bond weakening arises from cooperative back-bonding into the N2 pi orbitals. Increasing the coordination number of iron from three to four through binding of pyridines gives compounds with comparable N-N weakening, and both are substantially weakened relative to five-coordinate iron-N2 complexes, even those with a lower oxidation state. Treatment of L(R)FeNNFeL(R) with KC8 gives K2L(R)FeNNFeL(R), and calculations indicate that reduction of the iron and alkali metal coordination cooperatively weaken the N-N bond. The complexes L(R)FeNNFeL(R) react as iron(I) fragments, losing N2 to yield iron(I) phosphine, CO, and benzene complexes. They also reduce ketones and aldehydes to give the products of pinacol coupling. The K2L(R)FeNNFeL(R) compounds can be alkylated at iron, with loss of N2.
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Affiliation(s)
- Jeremy M Smith
- Department of Chemistry, University of Rochester, Rochester, New York 14267, USA
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88
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Affiliation(s)
- Guangcai Bai
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada, N9B3P4
| | - Pingrong Wei
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada, N9B3P4
| | - Douglas W. Stephan
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada, N9B3P4
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89
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Sciarone TJ, Meetsma A, Hessen B. Neutral and cationic Fe(II) β-diketiminate complexes. Inorganica Chim Acta 2006. [DOI: 10.1016/j.ica.2005.06.065] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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90
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Vela J, Vaddadi S, Kingsley S, Flaschenriem CJ, Lachicotte RJ, Cundari TR, Holland PL. Bidentate Coordination of Pyrazolate in Low-Coordinate Iron(II) and Nickel(II) Complexes. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200503535] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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91
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Vela J, Vaddadi S, Kingsley S, Flaschenriem CJ, Lachicotte RJ, Cundari TR, Holland PL. Bidentate Coordination of Pyrazolate in Low-Coordinate Iron(II) and Nickel(II) Complexes. Angew Chem Int Ed Engl 2006; 45:1607-11. [PMID: 16470750 DOI: 10.1002/anie.200503535] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Javier Vela
- Department of Chemistry, University of Rochester, Rochester, NY 14627, USA
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92
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Zhao P, Incarvito CD, Hartwig JF. Direct Observation of β-Aryl Eliminations from Rh(I) Alkoxides. J Am Chem Soc 2006; 128:3124-5. [PMID: 16522075 DOI: 10.1021/ja058550q] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
beta-Aryl eliminations from a series of rhodium(I) alkoxides to form rhodium aryl complexes and free ketones are reported. Tertiary phenylmethoxide complexes [Rh(PEt3)n(OCPhRR')] (n = 2, 3) were prepared via alcoholysis of {Rh(PEt3)2[N(SiMe3)2} by the corresponding alcohols HOCPhRR' in the presence and absence of added PEt3. Heating of these complexes in the presence of added PEt3 generated the rhodium phenyl complex, (PEt3)3RhPh, and the corresponding ketones in good to high yields. Kinetic results are most consistent with irreversible beta-phenyl elimination from a bisphosphine-ligated rhodium alkoxide complex. Such bisphosphine complexes result from ligand dissociation from the trisphosphine complexes and have been isolated in some cases. The bisphosphine complexes are stabilized by Rh-Cphenyl interactions, as evidenced by an X-ray structure, and this structure with a metal-aryl interaction likely illustrates the pathway for C-C bond cleavage.
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Affiliation(s)
- Pinjing Zhao
- Department of Chemistry, Yale University, PO Box 208107, New Haven, Connecticut 06520-8107, USA
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93
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Li Y, Wang L, Gao H, Zhu F, Wu Q. Novel nickel (II) complexes chelating β-diketiminate ligands: synthesis and simultaneous polymerization and oligomerization of ethylene. Appl Organomet Chem 2006. [DOI: 10.1002/aoc.1097] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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94
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Sciarone TJJ, Nijhuis CA, Meetsma A, Hessen B. Synthesis and reactivity of mono(amidinate) organoiron(ii) complexes. Dalton Trans 2006:4896-904. [PMID: 17047738 DOI: 10.1039/b608108h] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The mono(amidinate) iron(ii) ferrate complex [{PhC(NAr)(2)}FeCl(micro-Cl)Li(THF)(3)] (1, Ar = 2,6-iPr(2)C(6)H(3)) was prepared and was found to undergo ligand redistribution in non-coordinating solvents to give the homoleptic [{PhC(NAr)(2)}(2)Fe] (2) as the only isolable product. Reaction of with alkylating agents also induces this redistribution, but the presence of pyridine allows isolation of the four-coordinate 14 VE monoalkyl complex [{PhC(NAr)(2)}FeCH(2)SiMe(3)(py)] (4). Generation of the 12 VE alkyl via pyridine abstraction from 4 by B(C(6)F(5))(3) again induced ligand redistribution. Attempts to trap a 12 VE alkyl species with CO led to the isolation of a dimeric Fe(0)-Li-ferrate complex (3) with a carbamoyl ligand, derived from CO insertion into the iron-amidinate bond.
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Affiliation(s)
- Timo J J Sciarone
- Dutch Polymer Institute/Center for Catalytic Olefin Polymerization, Stratingh Institute for Chemistry and Chemical Engineering, University of Groningen, Nijenborgh 4, 9747, AG Groningen, The Netherlands
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95
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96
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Bai G, Wei P, Stephan DW. Α β-Diketiminato−Nickel(II) Synthon for Nickel(I) Complexes. Organometallics 2005. [DOI: 10.1021/om050544f] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Guangcai Bai
- Department of Chemistry & Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4
| | - Pingrong Wei
- Department of Chemistry & Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4
| | - Douglas W. Stephan
- Department of Chemistry & Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4
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97
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Stoian SA, Yu Y, Smith JM, Holland PL, Bominaar EL, Münck E. Mössbauer, electron paramagnetic resonance, and crystallographic characterization of a high-spin Fe(I) diketiminate complex with orbital degeneracy. Inorg Chem 2005; 44:4915-22. [PMID: 15998018 DOI: 10.1021/ic050321h] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The synthesis and X-ray structure of the low-coordinate, high-spin Fe(I) compound LFe(HCCPh) (L = HC(C[tBu]N[2,6-diisopropylphenyl])2]-), 1, are reported. Low-temperature Mössbauer and electron paramagnetic resonance (EPR) spectroscopies reveal that the electronic ground state is a Kramers doublet with uniaxial magnetic properties (effective g values g(x) = 8.9, 0 < g(y), g(z) < 0.3) that is well isolated from the excited states. The observation of a large and positive magnetic hyperfine field, B(int) = +68.8(3) T, demonstrates that the orbital angular moment is essentially unquenched along one spatial direction. Relaxation rates obtained from variable-temperature Mössbauer spectra were fit to an Orbach process, yielding delta = 130-190 cm(-1) for the energy gap ("zero-field splitting") between the two Kramers doublets of the S = 3/2 multiplet. Density functional theory (DFT) and time-dependent DFT calculations give insight into the electronic structures of the ground and excited states. The oxidation state of the iron and the bond order of the phenylacetylene ligand in complex 1 are analyzed using DFT, showing a substantial back-bonding interaction. Spin-orbit coupling acting in the subspace of quasi-degenerate z2 and yz orbitals provides a consistent description of both the zero-field splitting and magnetic hyperfine parameters that fits the EPR and Mössbauer data for 1. Interestingly, the spin-orbit coupling involves the same two orbitals (z2, yz) as in the analogous three-coordinate Fe(II) compounds, because back-bonding significantly lowers the energy of the xy orbital, making it the lowest doubly occupied d orbital. Despite the different oxidation state and different number of atoms in the first coordination sphere, the electronic structure of LFe(I)(HCCPh) can be interpreted similarly to that of three-coordinate Fe(II) diketiminate complexes, but with a substantial effect of back-bonding. To our knowledge, this is the first detailed Mössbauer and EPR study of a structurally characterized high-spin Fe(I) complex.
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Affiliation(s)
- Sebastian A Stoian
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
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98
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Castro PM, Lahtinen P, Axenov K, Viidanoja J, Kotiaho T, Leskelä M, Repo T. Activation of 2,6-Bis(imino)pyridine Iron(II) Chloride Complexes by Methylaluminoxane: An Electrospray Ionization Tandem Mass Spectrometry Investigation. Organometallics 2005. [DOI: 10.1021/om050351s] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Pascal M. Castro
- Laboratory of Inorganic Chemistry and Laboratory of Analytical Chemistry, Department of Chemistry, A.I. Virtasen Aukio 1, P.O. Box 55, University of Helsinki, FI-00014 Helsinki, Finland
| | - Petro Lahtinen
- Laboratory of Inorganic Chemistry and Laboratory of Analytical Chemistry, Department of Chemistry, A.I. Virtasen Aukio 1, P.O. Box 55, University of Helsinki, FI-00014 Helsinki, Finland
| | - Kirill Axenov
- Laboratory of Inorganic Chemistry and Laboratory of Analytical Chemistry, Department of Chemistry, A.I. Virtasen Aukio 1, P.O. Box 55, University of Helsinki, FI-00014 Helsinki, Finland
| | - Jyrki Viidanoja
- Laboratory of Inorganic Chemistry and Laboratory of Analytical Chemistry, Department of Chemistry, A.I. Virtasen Aukio 1, P.O. Box 55, University of Helsinki, FI-00014 Helsinki, Finland
| | - Tapio Kotiaho
- Laboratory of Inorganic Chemistry and Laboratory of Analytical Chemistry, Department of Chemistry, A.I. Virtasen Aukio 1, P.O. Box 55, University of Helsinki, FI-00014 Helsinki, Finland
| | - Markku Leskelä
- Laboratory of Inorganic Chemistry and Laboratory of Analytical Chemistry, Department of Chemistry, A.I. Virtasen Aukio 1, P.O. Box 55, University of Helsinki, FI-00014 Helsinki, Finland
| | - Timo Repo
- Laboratory of Inorganic Chemistry and Laboratory of Analytical Chemistry, Department of Chemistry, A.I. Virtasen Aukio 1, P.O. Box 55, University of Helsinki, FI-00014 Helsinki, Finland
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99
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Vela J, Smith JM, Yu Y, Ketterer NA, Flaschenriem CJ, Lachicotte RJ, Holland PL. Synthesis and Reactivity of Low-Coordinate Iron(II) Fluoride Complexes and Their Use in the Catalytic Hydrodefluorination of Fluorocarbons. J Am Chem Soc 2005; 127:7857-70. [PMID: 15913376 DOI: 10.1021/ja042672l] [Citation(s) in RCA: 293] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Transition metal fluoride complexes are of interest because they are potentially useful in a multitude of catalytic applications, including C-F bond activation and fluorocarbon functionalization. We report the first crystallographically characterized examples of molecular iron(II) fluorides: [L(Me)Fe(mu-F)]2 (1(2)) and L(tBu)FeF (2) (L = bulky beta-diketiminate). These complexes react with donor molecules (L'), yielding trigonal-pyramidal complexes L(R)FeF(L'). The fluoride ligand is activated by the Lewis acid Et2O.BF3, forming L(tBu)Fe(OEt2)(eta1-BF4) (3), and is also silaphilic, reacting with silyl compounds such as Me3SiSSiMe3, Me3SiCCSiMe3, and Et3SiH to give new thiolate L(tBu)FeSSiMe3 (4), acetylide L(tBu)FeCCSiMe3 (5), and hydride [L(Me)Fe(mu-H)]2 (6(2)) complexes. The hydrodefluorination (HDF) of perfluorinated aromatic compounds (hexafluorobenzene, pentafluoropyridine, and octafluorotoluene) with a silane R3SiH (R3 = (EtO)3, Et3, Ph3, (3,5-(CF3)2C6H3)Me2) is catalyzed by addition of an iron(II) fluoride complex, giving mainly the singly hydrodefluorinated products (pentafluorobenzene, 2,3,5,6-tetrafluoropyridine, and alpha,alpha,alpha,2,3,5,6-heptafluorotoluene, respectively) in up to five turnovers. These catalytic perfluoroarene HDF reactions proceed with activation of the C-F bond para to the most electron-withdrawing group and are dependent on the degree of fluorination and solvent polarity. Kinetic studies suggest that hydride generation is the rate-limiting step in the HDF of octafluorotoluene, but the active intermediate is unknown. Mechanistic considerations argue against oxidative addition and outer-sphere electron transfer pathways for perfluoroarene HDF. Fluorinated olefins are also hydrodefluorinated (up to 10 turnovers for hexafluoropropene), most likely through a hydride insertion/beta-fluoride elimination mechanism. Complexes 1(2) and 2 thus provide a rare example of a homogeneous system that activates C-F bonds without competitive C-H activation and use an inexpensive 3d transition metal.
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Affiliation(s)
- Javier Vela
- Department of Chemistry, University of Rochester, Rochester, New York 14627, USA
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Basuli F, Bailey BC, Watson LA, Tomaszewski J, Huffman JC, Mindiola DJ. Four-Coordinate Titanium Alkylidene Complexes: Synthesis, Reactivity, and Kinetic Studies Involving the Terminal Neopentylidene Functionality. Organometallics 2005. [DOI: 10.1021/om049400b] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Falguni Basuli
- Department of Chemistry and Molecular Structure Center, Indiana University, Bloomington, Indiana 47405
| | - Brad C. Bailey
- Department of Chemistry and Molecular Structure Center, Indiana University, Bloomington, Indiana 47405
| | - Lori A. Watson
- Department of Chemistry and Molecular Structure Center, Indiana University, Bloomington, Indiana 47405
| | - John Tomaszewski
- Department of Chemistry and Molecular Structure Center, Indiana University, Bloomington, Indiana 47405
| | - John C. Huffman
- Department of Chemistry and Molecular Structure Center, Indiana University, Bloomington, Indiana 47405
| | - Daniel J. Mindiola
- Department of Chemistry and Molecular Structure Center, Indiana University, Bloomington, Indiana 47405
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