Author: "Department of Chemistry [Berkeley]" / Topic: catalysis - Searchworks@Jio Institute Digital Library Search Results

Your search keyword '"Department of Chemistry [Berkeley]"' showing total 27 results

Start Over Author "Department of Chemistry [Berkeley]" Topic catalysis

27 results on '"Department of Chemistry [Berkeley]"'

1. Metallacyclic actinide catalysts for dinitrogen conversion to ammonia and secondary amines

Author: Rory P. Kelly, Tatsumi Ochiai, Megan L. Seymour, Laurent Maron, Polly L. Arnold, Francis Y. T. Lam, EPCC [Edinburgh], University of Edinburgh, Université de Tsukuba = University of Tsukuba, Department of Chemistry [Berkeley], University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), EaStCHEM School of Chemistry, University of St Andrews [Scotland], Nanomagnétisme (LPCNO), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), and Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Silanes, 010405 organic chemistry, General Chemical Engineering, Organic Chemistry, General Chemistry, Actinide, 010402 general chemistry, Ligands, 01 natural sciences, 0104 chemical sciences, Catalysis, Metal, Ammonia, chemistry.chemical_compound, Temperature and pressure, chemistry, visual_art, Polymer chemistry, Chemical Sciences, visual_art.visual_art_medium, Surface modification, Molecule, MESH: chemi, [CHIM]Chemical Sciences, Chemical bonding
Abstract: International audience; Chemists have spent over a hundred years trying to make ambient temperature/pressure catalytic systems that can convert atmospheric dinitrogen into ammonia or directly into amines. A handful of successful d-block metal catalysts have been developed in recent years, but even binding of dinitrogen to an f-block metal cation is extremely rare. Here we report f-block complexes that can catalyse the reduction and functionalization of molecular dinitrogen, including the catalytic conversion of molecular dinitrogen to a secondary silylamine. Simple bridging ligands assemble two actinide metal cations into narrow dinuclear metallacycles that can trap the diatom while electrons from an externally bound group 1 metal, and protons or silanes, are added, enabling dinitrogen to be functionalized with modest but catalytic yields of six equivalents of secondary silylamine per molecule at ambient temperature and pressure.
Published: 2020
Full Text: View/download PDF

2. Regiospecificity in Ligand-Free Pd-Catalyzed C–H Arylation of Indoles: LiHMDS as Base and Transient Directing Group

Author: Clément Camp, Marc Renom-Carrasco, Florian M. Wisser, Chloé Thieuleux, Jérôme Canivet, Yorck Mohr, Clément Demarcy, Eric Clot, Elsje Alessandra Quadrelli, Laboratoire de Chimie, Catalyse, Polymères et Procédés, R 5265 (C2P2), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, IRCELYON-Ingéniérie, du matériau au réacteur (ING), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), and Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)
Subjects: Indole test, chemistry.chemical_classification, Base (chemistry), Lithium hexamethyldisilazide, 010405 organic chemistry, Ligand, C-H arylation, chemistry.chemical_element, General Chemistry, LiHMDS, 010402 general chemistry, palladium, 01 natural sciences, Medicinal chemistry, Catalysis, 0104 chemical sciences, chemistry, indole, cross-coupling, [CHIM]Chemical Sciences, Palladium
Abstract: International audience; A highly efficient catalyst-base pair for the C-H arylation of free (NH)-indoles in the C-3 position is reported. Ligand-free palladium acetate coupled with lithium hexamethyldisilazide (LiHMDS) catalyzed the regiospecific, i.e. 100% regioselective, C-3 arylation of indoles with high turnover numbers. This catalytic system has been successfully applied to a wide range of substrates including various functional aryl halides and indolic cores. The unique role of LiHMDS as both a base and unexpected transient directing group has been revealed experimentally and elucidated computationally, in line with a Heck-type insertion-elimination mechanism.
Published: 2020
Full Text: View/download PDF

3. Synthesis and Structure of Uranium-Silylene Complexes

Author: Daniel J. Lussier, John Arnold, Michael A. Boreen, I. Joseph Brackbill, Laurent Maron, Iskander Douair, Department of Chemistry [Berkeley], University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Silicon, 010405 organic chemistry, Chemistry, Organic Chemistry, Silylene, chemistry.chemical_element, General Chemistry, Actinide, Uranium, 010402 general chemistry, 01 natural sciences, Bond order, Catalysis, 0104 chemical sciences, chemistry.chemical_compound, Crystallography, Covalent bond, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Carbene
Abstract: While carbene complexes of uranium have been known for over a decade, there are no reported examples of complexes between an actinide and a "heavy carbene." Herein, we report the syntheses and structures of the first uranium-heavy tetrylene complexes: (CpSiMe3 )3 U-Si[PhC(NR)2 ]R' (R=tBu, R'=NMe2 1; R=iPr, R'=PhC(NiPr)2 2). Complex 1 features a kinetically robust uranium-silicon bonding interaction, while the uranium-silicon bond in 2 is easily disrupted thermally or by competing ligands in solution. Calculations reveal polarized σ bonds, but depending on the substituents at silicon a substantial π-bonding interaction is also present. The complexes possess relatively high bond orders which suggests primarily covalent bonding between uranium and silicon. These results comprise a new frontier in actinide-heavy main-group bonding.
Published: 2020
Full Text: View/download PDF

4. Catalytic Olefin Hydrosilations Mediated by Ruthenium η3-H2Si σ Complexes of Primary and Secondary Silanes

Author: Mark C. Lipke, Odile Eisenstein, T. Don Tilley, Christophe Raynaud, Marie-Noëlle Poradowski, Rutgers, The State University of New Jersey [New Brunswick] (RU), Rutgers University System (Rutgers), Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, Interface Theory Experiment : Mechanism & Modeling (ITEMM), Institut de Chimie et Biochimie Moléculaires et Supramoléculaires (ICBMS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie du CNRS (INC)-École Supérieure Chimie Physique Électronique de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie du CNRS (INC)-École Supérieure Chimie Physique Électronique de Lyon-Centre National de la Recherche Scientifique (CNRS), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), and Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)
Subjects: Allyl chloride, Olefin fiber, Silanes, 010405 organic chemistry, Chemistry, Silylene, Cationic polymerization, chemistry.chemical_element, General Chemistry, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, Medicinal chemistry, Catalysis, 0104 chemical sciences, Ruthenium, chemistry.chemical_compound, Proton NMR, ComputingMilieux_MISCELLANEOUS
Abstract: Unambiguous examples of η3-H2SiH(R) complexes featuring a terminal Si–H bond have been prepared and examined as possible intermediates in olefin hydrosilation. These species were generated by displacement of the secondary silane ligands in [PhBPPh3]RuH[η3-H2SiMePh] (1b) (PhBPPh3 = PhB(CH2PPh2)3− by primary silanes RSiH3 to generate [PhBPPh3]RuH[η3-H2SiH(R)] (R = Cy (1d), CH2CH2Ph (1e), Trip = 2,4,6-iPr3C6H2 (1f)). Complexes 1d and 1e were characterized in solution, whereas 1f was isolated and studied in detail. Complex 1b is not a competent precatalyst for the hydrosilation of 1-hexene with CySiH3, whereas comparable conditions gave reasonable yields for the selective anti-Markovnikov hydrosilations of Cl3SiCH2CH═CH2 (89%), p-chlorostyrene (73%), and allyl chloride (70%). The 1H NMR spectrum of 1f collected at −30 °C displays a downfield signal (δ = 8.26 ppm) for the terminal Si–H bond that suggests electronic similarities between 1f and cationic silylene dihydrides [Cp*(iPr3P)Ru(H)2═SiH(R)]+ that mediate...
Published: 2018
Full Text: View/download PDF

5. A Terminal Fluoride Ligand Generates Axial Magnetic Anisotropy in Dysprosium Complexes

Author: Boris Le Guennic, Stéphane Rigaut, Lucy E. Darago, Jacob H. Olshansky, Jeffrey R. Long, Khetpakorn Chakarawet, Miguel I. Gonzalez, Lucie Norel, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Department of Chemistry [Berkeley], University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), 800719, H2020 Marie Skłodowska-Curie Actions, CHE-1464841, National Science Foundation, Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), University of California [Berkeley], and University of California-University of California
Subjects: Luminescence, Materials science, Physics::Optics, chemistry.chemical_element, 010402 general chemistry, 01 natural sciences, Catalysis, Condensed Matter::Materials Science, chemistry.chemical_compound, Ab initio quantum chemistry methods, Physics::Atomic and Molecular Clusters, Molecule, dysprosium, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Physics::Atomic Physics, 010405 organic chemistry, Ligand, ab initio calculations, General Medicine, General Chemistry, Magnetic susceptibility, structure determination, 0104 chemical sciences, Crystallography, Magnetic anisotropy, chemistry, Dysprosium, magnetic properties, Ground state, Fluoride
Abstract: International audience; The first dysprosium complexes with a terminal fluoride ligand are obtained as air-stable compounds. The strong, highly electrostatic dysprosium-fluoride bond generates a large axial crystal-field splitting of the J=15/2 ground state, as evidenced by high-resolution luminescence spectroscopy and correlated with the single-molecule magnet behavior through experimental magnetic susceptibility data and ab initio calculations.
Published: 2018
Full Text: View/download PDF

6. Access to Heteroleptic Fluorido-Cyanido Complexes with a Large Magnetic Anisotropy by Fluoride Abstraction

Author: Stephen Hill, Jun-Liang Liu, Andrei Rogalev, Samuel M. Greer, Itziar Oyarzabal, Jeffrey R. Long, Rodolphe Clérac, Fabrice Wilhelm, Kasper S. Pedersen, Alain Tressaud, Etienne Durand, Abhishake Mondal, Centre de Recherche Paul Pascal (CRPP), Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Technical University of Denmark [Lyngby] (DTU), National High Magnetic Field Laboratory (NHMFL), Florida State University [Tallahassee] (FSU), Department of Physics, European Synchrotron Radiation Facility (ESRF), Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Department of Chemistry, University of California, Berkeley, Department of Chemical & Biomolecular Engineering [Berkeley] (CBE), University of California [Berkeley], University of California-University of California, Lawrence Berkeley National Laboratory [Berkeley] (LBNL), the Danish Research Council for Independent Research for a DFF‐Sapere Aude Research Talent grant (4090‐00201), the University of Bordeaux, the ANR, the CNRS, the Region Nouvelle Aquitaine, the MOLSPIN COST action CA15128 and the GdR MCM‐2. Research at the University of California, Berkeley was supported by NSF Grant CHE‐1800252 to J.R.L. A portion of this work was performed at the National High Magnetic Field Laboratory, which is supported by the NSF Cooperative Agreement (DMR‐1644779) and the state of Florida. R.C and J.R.L. are grateful to the France‐Berkeley Fund and the CNRS (PICS N°06485) for funding. Support from the NSF Graduate Research Fellowship Program (DGE‐1449440). Support from the NSF (DMR‐1610226 to S.H.) is also acknowledged. I.O. and R.C. are grateful to the Basque Government for a postdoctoral grant of I.O. The X‐ray spectroscopy experiments were performed at the European Synchrotron Radiation Facility (ESRF, Grenoble, France). Dr. D. Sadhukhan is acknowledged for helpful discussions about the synthesis., Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Facultad de Quimica de San Sebastian, Universidad del Pais Vasco, Universidad del Pais Vasco / Euskal Herriko Unibertsitatea [Espagne] (UPV/EHU), Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux-Centre National de la Recherche Scientifique (CNRS), Department of Chemistry [Berkeley], and K.S.P. and R.C. thank the Danish Research Council for Independent Research for a DFF‐Sapere Aude Research Talent grant (4090‐00201), the University of Bordeaux, the ANR, the CNRS, the Region Nouvelle Aquitaine, the MOLSPIN COST action CA15128 and the GdR MCM‐2. Research at the University of California, Berkeley was supported by NSF Grant CHE‐1800252 to J.R.L. A portion of this work was performed at the National High Magnetic Field Laboratory, which is supported by the NSF Cooperative Agreement (DMR‐1644779) and the state of Florida. R.C and J.R.L. are grateful to the France‐Berkeley Fund and the CNRS (PICS N°06485) for funding. S.M.G. acknowledges support from the NSF Graduate Research Fellowship Program (DGE‐1449440). Support from the NSF (DMR‐1610226 to S.H.) is also acknowledged. I.O. and R.C. are grateful to the Basque Government for a postdoctoral grant of I.O. The X‐ray spectroscopy experiments were performed at the European Synchrotron Radiation Facility (ESRF, Grenoble, France). Dr. D. Sadhukhan is acknowledged for helpful discussions about the synthesis.
Subjects: Ligand field theory, Materials science, 010405 organic chemistry, General Chemistry, General Medicine, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 01 natural sciences, Catalysis, law.invention, 0104 chemical sciences, chemistry.chemical_compound, Magnetization, Magnetic anisotropy, Crystallography, chemistry, Transition metal, law, Molecule, Homoleptic, Electron paramagnetic resonance, Fluoride
Abstract: International audience; Silicon-mediated fluoride abstraction is demonstrated as a means of generating the first fluorido-cyanido transition metal complexes. This new synthetic approach is exemplified by the synthesis and characterization of the heteroleptic complexes, trans-[M IV F 4 (CN) 2 ] 2À (M = Re, Os), obtained from their homoleptic [M IV F 6 ] 2À parents. As shown by combined high-field electron paramagnetic resonance spectroscopy and magnetization measurements, the partial substitution of fluoride by cyanide ligands leads to a marked increase in the magnetic anisotropy of trans-[ReF 4 (CN) 2 ] 2À as compared to [ReF 6 ] 2À , reflecting the severe departure from an ideal octahedral (O h point group) ligand field. This methodology paves the way toward the realization of new heteroleptic transition metal complexes that may be used as highly anisotropic building-blocks for the design of high-performance molecule-based magnetic materials.
Published: 2019
Full Text: View/download PDF

7. [UF6](2-): A molecular hexafluorido actinide(IV) complex with compensating spin and orbital magnetic moments

Author: Andrei Rogalev, Daniel Aravena, Katie R. Meihaus, Rodolphe Clérac, Fabrice Wilhelm, Eliseo Ruiz, Kasper S. Pedersen, Jesper Bendix, Martín Amoza, Jeffrey R. Long, Department of Chemistry, Technical University of Denmark, Lyngby, Department of Chemistry, University of California Berkeley, European Synchrotron Radiation Facility (ESRF), Universidad de Santiago de Chile [Santiago] (USACH), Departament de Quimica Inortganica i Organica and Institut de Quimica Teorica i Computacional, Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, Department of Chemistry [Copenhagen], Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Centre de Recherche Paul Pascal (CRPP), and Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Electronic structure, Urani, Metalls de terres rares, 010402 general chemistry, 01 natural sciences, Molecular physics, Catalysis, Ion, Magnetization, Fluorides, Ab initio quantum chemistry methods, Spectroscopy, Spin (physics), Physics, Magnetic moment, actinides, 010405 organic chemistry, Magnetic circular dichroism, Rare earth metals, General Chemistry, General Medicine, [CHIM.MATE]Chemical Sciences/Material chemistry, Espectroscòpia de raigs X, 0104 chemical sciences, Imants, Magnets, X-ray spectroscopy, Uranium, magnetic properties
Abstract: The first structurally characterized hexafluorido complex of a tetravalent actinide ion, the [UF6]2− anion, is reported in the (NEt4)2[UF6]⋅2 H2O salt (1). The weak magnetic response of 1 results from both UIV spin and orbital contributions, as established by combining X‐ray magnetic circular dichroism (XMCD) spectroscopy and bulk magnetization measurements. The spin and orbital moments are virtually identical in magnitude, but opposite in sign, resulting in an almost perfect cancellation, which is corroborated by ab initio calculations. This work constitutes the first experimental demonstration of a seemingly non‐magnetic molecular actinide complex carrying sizable spin and orbital magnetic moments.
Published: 2019
Full Text: View/download PDF

8. A Uranium Tri-Rhenium Triple Inverse Sandwich Compound

Author: John Arnold, Trevor D. Lohrey, Guodong Rao, Laurent Maron, Michael A. Boreen, R. David Britt, Department of Chemistry [Berkeley], University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences Heavy Element Chemistry Program of the U.S. Department of Energy (DOE) at LBNL [DE-AC02-05CH11231], National Science Foundation Graduate Research Fellowship Program [DGE 1106400], U.S. DOE Integrated University Program, National Institutes of Health [1R35GM126961-01], Chinese Academy of Science, Humboldt Foundation, and Office of Science, Office of Basic Energy Sciences, of the U.S. DOE [DE-AC02-05CH11231]
Subjects: Models, Molecular, Molecular Conformation, chemistry.chemical_element, Salt (chemistry), Crystallography, X-Ray, 010402 general chemistry, Metathesis, 01 natural sciences, Biochemistry, Catalysis, Adduct, law.invention, chemistry.chemical_compound, Colloid and Surface Chemistry, law, Organometallic Compounds, Lewis acids and bases, Electron paramagnetic resonance, chemistry.chemical_classification, General Chemistry, Rhenium, Uranium, 0104 chemical sciences, Crystallography, chemistry, Sandwich compound, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph]
Abstract: International audience; Salt metathesis between the anionic rhenium(I) compound, Na[Re(eta(5)-Cp)(BDI)] (BDI = N,N'-bis(2,6-diisopropylphenyl)-3,5-dimethyl-beta-diketiminate), and the uranium(III) salt, UI3 (1,4-dioxane)(1.5), generated the triple inverse sandwich complex, U[(mu-eta(5):eta(5)-Cp)Re(BDI)(3), which was isolated and structurally characterized as the Lewis base adducts, (L)U[(mu-eta(5):eta(5)-Cp)Re(BDI)](3) (1.L, L = THF, 1,4-dioxane, DMAP). The assignment as one uranium(III) and three rhenium(I) centers was supported by X-ray crystallography, NMR and EPR spectroscopies, and computational studies. An unusual shortening of the rhenium-Cp bond distances in 1.L relative to Na[Re(eta(5)-Cp)(BDI)] was observed in the solid-state and reproduced in calculated structures of 1-THF and the anionic fragment, [Re(eta(5)-Cp)(BDI)](-). Calculations suggest that the electropositive uranium center pulls electron density away from the electron-rich rhenium centers, reducing electron-electron repulsions in the rhenium-Cp moieties and thereby strengthening those interactions, while also making uranium-Cp bonding more favorable.
Published: 2019
Full Text: View/download PDF

9. The Nature of Secondary Interactions at Electrophilic Metal Sites of Molecular and Silica-Supported Organolutetium Complexes from Solid-State NMR Spectroscopy

Author: Richard A. Andersen, Laurent Maron, Christophe Copéret, Anne Lesage, Wayne W. Lukens, Kevin J. Sanders, David Gajan, Iker del Rosal, Matthew P. Conley, Giuseppe Lapadula, Department of Chemistry and Applied Biosciences [ETH Zürich], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Biological Solid-State NMR Methods - Méthodes de RMN à l'état solide en biologie, Institut des Sciences Analytiques (ISA), Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Solid-State NMR Methods for Materials - Méthodes de RMN à l'état solide pour les matériaux, Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Lawrence Berkeley National Laboratory [Berkeley] (LBNL), Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, C.C. thanks the Miller Institute for a Visiting Professor position at UC Berkeley, during which this manuscript was finalized. Portions of this work were performed at Lawrence Berkeley National Laboratory under contract no. DE-AC02-05CH11231 and at the Stanford Synchrotron Radiation Lightsource (SSRL). Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under contract no. DE-AC02-76SF00515. Portions of this work were supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Chemical Sciences, Biosciences, and Geosciences Division (CSGB), Heavy Element Chemistry Program and were performed at Lawrence Berkeley National Laboratory under contract no. DE-AC02-05CH11231. We also thank the HPCs CALcul en Midi-Pyrennes (CALIMP-EOS, grant P0833) for the generous allocation of computer time. Financial support from the TGIR-RMN-THC Fr3050 CNRS for conducting the research is gratefully acknowledged., Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), University of California [Berkeley] (UC Berkeley), and University of California (UC)-University of California (UC)
Subjects: 010405 organic chemistry, Chemistry, Resonance, Nanotechnology, General Chemistry, Nuclear magnetic resonance spectroscopy, 010402 general chemistry, 01 natural sciences, Biochemistry, Catalysis, Spectral line, 0104 chemical sciences, Crystallography, Colloid and Surface Chemistry, Solid-state nuclear magnetic resonance, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Chemical Sciences, Electrophile, Proton NMR, [CHIM]Chemical Sciences, Spectroscopy, Natural bond orbital
Abstract: International audience; Lu[CH(SiMe3)2]3 reacts with [SiO2-700] to give [(≡SiO)Lu[CH(SiMe3)2]2] and CH2(SiMe3)2. [(≡SiO)Lu[CH(SiMe3)2]2] is characterized by solid-state NMR and EXAFS spectroscopy, which show that secondary Lu···C and Lu···O interactions, involving a γ-CH3 and a siloxane bridge, are present. From X-ray crystallographic analysis, the molecular analogues Lu[CH(SiMe3)2]3-x[O-2,6-tBu-C6H3]x (x = 0-2) also have secondary Lu···C interactions. The (1)H NMR spectrum of Lu[CH(SiMe3)2]3 shows that the -SiMe3 groups are equivalent to -125 °C and inequivalent below that temperature, ΔG(⧧)(Tc = 148 K) = 7.1 kcal mol(-1). Both -SiMe3 groups in Lu[CH(SiMe3)2]3 have (1)JCH = 117 ± 1 Hz at -140 °C. The solid-state (13)C CPMAS NMR spectrum at 20 °C shows three chemically inequivalent resonances in the area ratio of 4:1:1 (12:3:3); the J-resolved spectra for each resonance give (1)JCH = 117 ± 2 Hz. The (29)Si CPMAS NMR spectrum shows two chemically inequivalent resonances with different values of chemical shift anisotropy. Similar observations are obtained for Lu[CH(SiMe3)2]3-x[O-2,6-tBu-C6H3]x (x = 1 and 2). The spectroscopic data point to short Lu···Cγ contacts corresponding to 3c-2e Lu···Cγ-Siβ interactions, which are supported by DFT calculations. Calculated natural bond orbital (NBO) charges show that Cγ carries a negative charge, while Lu, Hγ, and Siβ carry positive charges; as the number of O-based ligands increases so does the positive charge at Lu, which in turns shortens the Lu···Cγ distance. The change in NBO charges and the resulting changes in the spectroscopic and crystallographic properties show how ligands and surface-support sites rearrange to accommodate these changes, consistent with Pauling's electroneutrality concept.
Published: 2016
Full Text: View/download PDF

10. Heterotetrametallic Re-Zn-Zn-Re Complex Generated by an Anionic Rhenium(I) β-Diketiminate

Author: Robert G. Bergman, Laurent Maron, John Arnold, Trevor D. Lohrey, Department of Chemistry [Berkeley], University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), NSF [CHE1465188], U.S. DOE Integrated University Program, Chinese Academy of Science, Humboldt Foundation, and Office of Science, Office of Basic Energy Sciences, of the U.S. DOE [DE-AC02-05CH11231]
Subjects: Hydride, chemistry.chemical_element, Protonation, General Chemistry, Zinc, Rhenium, 010402 general chemistry, 01 natural sciences, Biochemistry, Catalysis, 0104 chemical sciences, β diketiminate, Colloid and Surface Chemistry, chemistry, Covalent bond, Polymer chemistry, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Trifluoromethanesulfonate
Abstract: International audience; We report the synthesis of an anionic rhenium(I) compound, Na[Re(eta(5)-Cp)(BDI)] (1; Cp = cyclopentadienide, BDI = N,N'-bis(2,6-diisopropylphenyl)-3,5-dimethyl-beta-diketiminate) and initial investigations of its use as a strong chemical reductant and metalloligand. Chemical oxidation of 1 gives a rare example of a rhenium(II) compound Re(eta(5)-Cp)(BDI) (2), while protonation of 1 yields the rhenium(III) hydride complex Re(H)(eta(5)-Cp)(BDI) (3). The reaction of 1 with ZnCl2 generated both 2 and the zinc(I) compound [ZnRe(eta(5)-Cp)(BDI)](2) (4), which features a linear, tetrametallic Re(I)-Zn(I)-Zn(I)-Re(I) core. Computational studies of 4 were performed to characterize the metal-metal bonding interactions; the results indicate a dative interaction from rhenium to zinc and covalent bonding between the two zinc centers. One-electron oxidation of 4 yielded both 2 and the triflate-bridged zinc(II) complex [(mu-OTOZnRe(eta(5)-Cp)(BDI)](2) (5, OTf = trifluoromethanesulfonate).
Published: 2018
Full Text: View/download PDF

11. Tristability in a Light-Actuated Single-Molecule Magnet

Author: Michael L. Aubrey, Corine Mathonière, Xiaowen Feng, Jeffrey R. Long, Mathieu Rouzières, Miguel I. Gonzalez, Rodolphe Clérac, Ie-Rang Jeon, Andrew Ozarowski, Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université de Bordeaux (UB), Centre de recherches Paul Pascal (CRPP), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), National High Magnetic Field Laboratory, Materials Science Division [LBNL Berkeley], and Lawrence Berkeley National Laboratory [Berkeley] (LBNL)
Subjects: Kerr effect, Bistability, 010405 organic chemistry, Chemistry, Binary number, [CHIM.MATE]Chemical Sciences/Material chemistry, General Chemistry, 010402 general chemistry, 01 natural sciences, Biochemistry, Molecular physics, Catalysis, 0104 chemical sciences, Magnetic field, Crystallography, Colloid and Surface Chemistry, Magnet, Molecule, Single-molecule magnet, Ternary operation
Abstract: 5 pages; International audience; Molecules exhibiting bistability have been proposed as elementary binary units (bits) for information storage, potentially enabling fast and efficient computing. In particular, transition metal complexes can display magnetic bistability via either spincrossover or single-molecule magnet behavior. We now show that the octahedral iron(II) complexes in the molecular salt [Fe(1-propyltetrazole)6](BF4)2, when placed in its high-symmetry form, can combine both types of behavior. Light irradiation under an applied magnetic field enables fully reversible switching between an S = 0 state and an S= 2 state with either up (MS = +2) or down (MS = −2) polarities. The resulting tristability suggests the possibility of using molecules for ternary information storage in direct analogy to current binary systems that employ magnetic switching and the magneto-optical Kerr effect as write and read mechanisms.
Published: 2013
Full Text: View/download PDF

12. Carbon-Nitrogen Bond Cleavage by a Thorium-NHC-bpy Complex

Author: Laurent Maron, Stephan Hohloch, John Arnold, Mary E. Garner, Department of Chemistry [Berkeley], University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), University of California [Berkeley], University of California-University of California, Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)
Subjects: Models, Molecular, Stereochemistry, Nitrogen, Isocyanide, Radical, Alkylation, 010402 general chemistry, Crystallography, X-Ray, 01 natural sciences, Catalysis, chemistry.chemical_compound, Bipyridine, 2,2'-Dipyridyl, Heterocyclic Compounds, Carbon–nitrogen bond, Organometallic Compounds, [CHIM]Chemical Sciences, Reactivity (chemistry), Molecular Structure, 010405 organic chemistry, Chemistry, Thorium, General Medicine, General Chemistry, Combinatorial chemistry, Small molecule, Carbon, 3. Good health, 0104 chemical sciences, Chemical bond, Methane
Abstract: International audience; Actinide complexes demonstrate unparalleled reactivity towards small molecules. However, utilizing these powerful transformations in a predictable and deliberate manner remains challenging. Therefore, developing actinide systems that not only perform noteworthy chemistry but also demonstrate controllable reactivity is a key goal. We describe a bis(NHC)borate thorium‐bpy complex (1) that is capable of reductively cleaving the R−NC bond in a series of organic isocyanides. In contrast to most actinide‐mediated bond activations, the dealkylation event mediated by 1 is remarkably general and yields very well‐defined products that assist in mechanistic elucidation. Synthesis of the rearranged but‐3‐enyl product from the reaction of 1 and cyclopropylmethyl isocyanide supports the notion of a radical‐based mechanism.
Published: 2016

13. Homoleptic two-coordinate silylamido complexes of chromium(I), manganese(I), and cobalt(I)

Author: Philip C. Bunting, Sébastien Bontemps, Laure Vendier, Sylviane Sabo-Etienne, Mihail Atanasov, Elizaveta A. Suturina, Jeffrey R. Long, C. Gunnar Werncke, Frank Neese, Laboratoire de chimie de coordination (LCC), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Max Planck Institute for Chemical Energy Conversion, Max-Planck-Gesellschaft, Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA, affiliation inconnue, Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, Institute of General and Inorganic Chemistry, and Bulgarian Academy of Sciences (BAS)
Subjects: Steric effects, 010405 organic chemistry, Chemistry, Ligand, Stereochemistry, Dimer, Organic Chemistry, General Chemistry, Nuclear magnetic resonance spectroscopy, 010402 general chemistry, 01 natural sciences, Magnetic susceptibility, Catalysis, 0104 chemical sciences, Crystallography, chemistry.chemical_compound, Molecule, Reactivity (chemistry), [CHIM.COOR]Chemical Sciences/Coordination chemistry, Homoleptic
Abstract: International audience; Anionic two-coordinate complexes of first-row transition-metal(I) centres are rare molecules that are expected to reveal new magnetic properties and reactivity. Recently, we demonstrated that a N(SiMe3)(2)(-) ligand set, which is unable to prevent dimerisation or extraneous ligand coordination at the +2 oxidation state of iron, was nonetheless able to stabilise anionic two-coordinate Fe-I complexes even in the presence of a Lewis base. We now report analogous Cr-I and Co-I complexes with exclusively this amido ligand and the isolation of a [Mn-IN(SiMe3)(2)(2)](2)(2-) dimer that features a Mn Mn bond. Additionally, by increasing the steric hindrance of the ligand set, the two-coordinate complex [Mn-IN(Dipp)(SiMe3)(2)](-) was isolated (Dipp= 2,6-iPr(2)-C6H3). Characterisation of these compounds by using X-ray crystallography, NMR spectroscopy, and magnetic susceptibility measurements is provided along with ligand-field analysis based on CASSCF/NEVPT2 ab initio calculations.
Published: 2016
Full Text: View/download PDF

14. Multifaceted magnetization dynamics in the mononuclear complex [ReIVCl4(CN)2]2

Author: David Aguilà, Marc Sigrist, Dumitru Samohvalov, Ming-Liang Tong, Jeffrey R. Long, Jesper Bendix, Karsten Holldack, Jun-Liang Liu, Alexander Schnegg, Hannu Mutka, Joscha Nehrkorn, Xiaowen Feng, Kasper S. Pedersen, Rodolphe Clérac, Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, MOE Key Lab of Bioinorganic and Synthetic Chemistry, Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université de Bordeaux (UB), Berlin Joint EPR Laboratory, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (Helmholtz-Zentrum Berlin), Helmholtz-Zentrum Berlin, Department of Chemistry [Copenhagen], Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Institut Laue-Langevin (ILL), ILL, Institute of Chemistry, Academia Sinica, Centre de Recherche Paul Pascal (CRPP), Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Materials Science Division [LBNL Berkeley], Lawrence Berkeley National Laboratory [Berkeley] (LBNL), and National Science Foundation (NSF) under Grant CHE-1464841, the CNRS (PICS No.06485), the University of Bordeaux, the Conseil Regional d’Aquitaine, the ANR, the French Embassy in the US (Chateaubriand fellowship for X. F.), the GdR MCM-2 and Sun Yat-Sen University (the International Program of Project 985 for J.-L. L.).K. S. P. thanks the Danish Research Council for Independent Research for a DFF-Sapere Aude Research Talent grant (4090-00201). The low temperature crystal structure was collected at the Stanford Nano Shared Facilities (SNSF), supported by theNSF under award ECCS-1542152.
Subjects: Magnetization dynamics, 010405 organic chemistry, Chemistry, Relaxation (NMR), Metals and Alloys, Relaxation process, Large scale facilities for research with photons neutrons and ions, General Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 01 natural sciences, Catalysis, Inelastic neutron scattering, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, law.invention, Nuclear magnetic resonance, law, Chemical physics, Materials Chemistry, Ceramics and Composites, Electron paramagnetic resonance
Abstract: International audience; The mononuclear complex (Bu4N)2[ReIVCl4(CN)2].2DMA (DMA =N,N-dimethylacetamide) displays intricate magnetization dynamics, implying Orbach, direct, and Raman-type relaxation processes. The Orbach relaxation process is characterized by an energy barrier of 39 K (27 cm-1) that is discussed based on high-field electron paramagnetic resonance (EPR), inelastic neutron scattering and frequency domain THz EPR investigations.
Published: 2016
Full Text: View/download PDF

15. Facile Interconversion of [Cp2(Cl)Hf(SnH3)] and [Cp2(Cl)Hf(μ-H)SnH2]: DFT Investigations of Hafnocene Stannyl Complexes as Masked Stannylenes

Author: Christophe Raynaud, Odile Eisenstein, Laurent Maron, T. Don Tilley, Julie Guihaumé, Lionel Perrin, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Chemistry [Berkeley], University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), University of California [Berkeley], and University of California-University of California
Subjects: 010405 organic chemistry, Chemistry, DFT -stannylenes, stannane dehydrocoupling, General Medicine, General Chemistry, alpha-elimination, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, Photochemistry, Metathesis, 01 natural sciences, Medicinal chemistry, Catalysis, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, chemistry.chemical_compound, hafnocene, Metallocene
Abstract: International audience; Sn two-step: Dehydrocoupling of stannanes by the d0 complex [Cp2(Cl)HfH] preferentially occurs by two successive reactions (see scheme): -bond metathesis to form [Cp2(Cl)Hf(SnH3)] and subsequent stannylene transfer into the Cp2(Cl)HfSnH3 bond. [Cp2(Cl)Hf(SnH3)] readily isomerizes to a species possessing a reactive stannylene unit, [Cp2(Cl)Hf(-H)SnH2], thus making the stannylene-transfer reaction energetically feasible.
Published: 2010
Full Text: View/download PDF

16. Bond Activations of PhSiH3 by Cp2SmH: A Mechanistic Investigation by the DFT Method

Author: Lionel Perrin, Odile Eisenstein, Laurent Maron, T. Don Tilley, Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), University of California [Berkeley] (UC Berkeley), and University of California (UC)-University of California (UC)
Subjects: 010405 organic chemistry, Hydride, Bond, Organic Chemistry, chemistry.chemical_element, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, Catalysis, Gibbs free energy, Inorganic Chemistry, Samarium, symbols.namesake, chemistry, Computational chemistry, Mechanism (philosophy), symbols, Redistribution (chemistry), [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Physical and Theoretical Chemistry, ComputingMilieux_MISCELLANEOUS
Abstract: In this paper, a theoretical investigation of bond activations of PhSiH3, catalyzed by Cp2SmH, is proposed by examination of the energy profiles of these reactions. The formation of the minor and major products observed experimentally is rationalized. The experimentally proposed two-step mechanism, starting with a Si−C activation to give Cp2SmPh as an intermediate, is confirmed. The second step involves reaction of this intermediate with the Si−H bond of PhSiH3 to give Ph2SiH2 and regenerate the samarium hydride. The relative free enthalpy barriers of these two steps are in agreement with the lack of observation of any intermediate during the catalytic reaction. In addition to the main experimentally proposed mechanism, a second mechanism that involves two successive Si−H activations is proposed in order to account for the formation of byproducts. Theoretically, these two reactions are demonstrated to occur competitively, which explains the formation of secondary products arising from redistribution and d...
Published: 2009
Full Text: View/download PDF

17. Decamethylytterbocene Complexes of Bipyridines and Diazabutadienes: Multiconfigurational Ground States and Open-Shell Singlet Formation

Author: Odile Eisenstein, Daniel Kazhdan, Eric D. Bauer, Marc D. Walter, Richard A. Andersen, Laurent Maron, Yung-Jin Hu, Wayne W. Lukens, Corwin H. Booth, Chemical Sciences Division [LBNL Berkeley] (CSD), Lawrence Berkeley National Laboratory [Berkeley] (LBNL), Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, Nuclear Science Division [LBNL Berkeley] (NSD), Materials Physics and Applications Division, Los Alamos National Laboratory (LANL), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Valence (chemistry), 010405 organic chemistry, Magnetism, Chemistry, General Chemistry, 010402 general chemistry, 01 natural sciences, Biochemistry, Catalysis, 0104 chemical sciences, Crystallography, Bipyridine, chemistry.chemical_compound, Colloid and Surface Chemistry, Computational chemistry, Density functional theory, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Singlet state, Complete active space, Open shell, HOMO/LUMO, ComputingMilieux_MISCELLANEOUS
Abstract: Partial ytterbium f-orbital occupancy (i.e., intermediate valence) and open-shell singlet formation are established for a variety of bipyridine and diazabutadiene adducts with decamethylytterbocene, (C(5)Me(5))(2)Yb, abbreviated as Cp*(2)Yb. Data used to support this claim include ytterbium valence measurements using Yb L(III)-edge X-ray absorption near-edge structure spectroscopy, magnetic susceptibility, and complete active space self-consistent field (CASSCF) multiconfigurational calculations, as well as structural measurements compared to density functional theory calculations. The CASSCF calculations indicate that the intermediate valence is the result of a multiconfigurational ground-state wave function that has both an open-shell singlet f(13)(pi*)(1), where pi* is the lowest unoccupied molecular orbital of the bipyridine or diazabutadiene ligands, and a closed-shell singlet f(14) component. A number of other competing theories for the unusual magnetism in these materials are ruled out by the lack of temperature dependence of the measured intermediate valence. These results have implications for understanding chemical bonding not only in organolanthanide complexes but also for f-element chemistry in general, as well as understanding magnetic interactions in nanoparticles and devices.
Published: 2009
Full Text: View/download PDF

18. Donor-Promoted 1,2-Hydrogen Migration from Silicon to a Saturated Ruthenium Center and Access to Silaoxiranyl and Silaiminyl Complexes

Author: Odile Eisenstein, Christophe Raynaud, T. Don Tilley, Hsueh-Ju Liu, Clark R. Landis, Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), and Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)
Subjects: Silanes, Chemistry, Silylene, chemistry.chemical_element, General Chemistry, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, Photochemistry, Biochemistry, Medicinal chemistry, Catalysis, 3. Good health, Ruthenium, chemistry.chemical_compound, Electron transfer, Colloid and Surface Chemistry, Deprotonation, Tosyl, Benzophenone, Reactivity (chemistry)
Abstract: International audience; Masked silylene complexes Cp*(IXy-H)(H)RuSiH2R (R = Mes (3) and Trip (4); IXy = 1,3-bis(2,6-dimethylphenyl)imidazol-2-ylidene; “IXy-H” is the deprotonated form of IXy) exhibit metallosilylene-like (LnM–Si–R) reactivity, as observed in reactions of nonenolizable ketones, enones, and tosyl azides, to give unprecedented silaoxiranyl, oxasilacyclopentenyl, and silaiminyl complexes, respectively. Notably, these silicon-containing complexes are derived from the primary silanes MesSiH3 and TripSiH3 via activation of all three Si–H bonds. DFT calculations suggest that the mechanism of formation for the silaoxiranyl complex Cp*(IXy)(H)2Ru–Si(OCPh2)Trip (6) involves coordination of benzophenone to a silylene silicon atom, followed by a single-electron transfer in which Si-bonded, non-innocent benzophenone accepts an electron from the reactive, electron-rich ruthenium center. Importantly, this electron transfer promotes an unusual 1,2-hydrogen migration to the resulting, more electron-deficient ruthenium center via a diradicaloid transition state.
Published: 2015
Full Text: View/download PDF

19. 1,2-Hydrogen Migration to a Saturated Ruthenium Complex via Reversal of Electronic Properties for Tin in a Stannylene-to-Metallostannylene Conversion

Author: Odile Eisenstein, T. Don Tilley, Thomas Davin, Hsueh-Ju Liu, Christophe Raynaud, Julie Guihaumé, Department of Chemistry [Berkeley], University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de chimie théorique (LCT), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), University of California [Berkeley], University of California-University of California, and Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)
Subjects: Hydrogen, Chemistry, Ligand, chemistry.chemical_element, Electron donor, General Chemistry, Photochemistry, Biochemistry, Acceptor, Catalysis, Ruthenium, Metal, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, chemistry.chemical_compound, Colloid and Surface Chemistry, Intramolecular force, visual_art, visual_art.visual_art_medium, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Tin
Abstract: International audience; An intramolecular 1,2(α)-H migration in a saturated ruthenium stannylene complex, to form a ruthenostannylene complex, involves a reversal of the role for a coordinated stannylene ligand, from that of an electron donor to an acceptor in the transition state. This change in the bonding properties for a stannylene group, with a simple molecular motion, lifts the usual requirement for generation of an unsaturated metal center in migration chemistry.
Published: 2014
Full Text: View/download PDF

20. Cyclometalated N-Heterocyclic Carbene Complexes of Ruthenium for Access to Electron-Rich Silylene Complexes That Bind the Lewis Acids CuOTf and AgOTf

Author: T. Don Tilley, Odile Eisenstein, Hsueh-Ju Liu, Christophe Raynaud, Department of Chemistry [Berkeley], University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de chimie théorique (LCT), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), University of California [Berkeley], University of California-University of California, and Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)
Subjects: 010405 organic chemistry, Stereochemistry, Silylene, chemistry.chemical_element, General Chemistry, 010402 general chemistry, 01 natural sciences, Biochemistry, Catalysis, Cycloaddition, 0104 chemical sciences, Ruthenium, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, chemistry.chemical_compound, Colloid and Surface Chemistry, Deprotonation, chemistry, Reactivity (chemistry), [CHIM.COOR]Chemical Sciences/Coordination chemistry, Lewis acids and bases, Carbene, Bond cleavage
Abstract: International audience; The synthesis of the cyclometalated complexes Cp*Ru(IXy-H) (2) [IXy = 1,3-bis(2,6-dimethylphenyl)imidazol-2-ylidene; IXy-H = 1-(2-CH2C6H3-6-methyl)-3-(2,6-dimethylphenyl)imidazol-2-ylidene-1-yl (the deprotonated form of IXy); Cp* = η5-C5Me5] and Cp*Ru(IXy-H)(N2) (3) was achieved by dehydrochlorination of Cp*Ru(IXy)Cl (1) with KCH2Ph. Complexes 2 and 3 activate primary silanes (RSiH3) to afford the silyl complexes Cp*(IXy-H)(H)RuSiH2R [R = p-Tol (4), Mes (5), Trip (6)]. Density functional theory studies indicated that these complexes are close in energy to the corresponding isomeric silylene species Cp*(IXy)(H)Ru═SiHR. Indeed, reactivity studies indicated that various reagents trap the silylene isomer of 6, Cp*(IXy)(H)Ru═SiHTrip (6a). Thus, benzaldehyde reacts with 6 to give the [2 + 2] cycloaddition product 7, while 4-bromoacetophenone reacts via C-H bond cleavage and formation of the enolate Cp*(IXy)(H)2RuSiH[OC(═CH2)C6H4Br]Trip (8). Addition of the O-H bond of 2,6-dimethylphenol across the Ru═Si bond of 6a gives Cp*(IXy)(H)2RuSiH(2,6-Me2C6H3O)Trip (9). Interestingly, CuOTf and AgOTf also react with 6 to provide unusual Lewis acid-stabilized silylene complexes in which MOTf bridges the Ru-Si bond. The AgOTf complex, which was crystallographically characterized, exhibits a structure similar to that of [Cp*(iPr3P)Ru(μ-H)2SiHMes]+, with a three-center, two-electron Ru-Ag-Si interaction. Natural bond orbital analysis of the MOTf complexes supported this type of bonding and characterized the donor interaction with Ag (or Cu) as involving a delocalized interaction with contributions from the carbene, silylene, and hydride ligands of Ru.
Published: 2014
Full Text: View/download PDF

21. Activation of White Phosphorus by Low-Valent Group 5 Complexes: Formation and Reactivity of cyclo-P4 Inverted Sandwich Compounds

Author: Laurent Maron, John Arnold, Clément Camp, Robert G. Bergman, Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, Laboratoire de physique et chimie des nano-objets (LPCNO), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Phosphide, Stereochemistry, Tantalum, chemistry.chemical_element, Protonation, Electronic structure, Crystallography, X-Ray, 010402 general chemistry, 01 natural sciences, Biochemistry, Article, Catalysis, law.invention, chemistry.chemical_compound, Colloid and Surface Chemistry, Hydrogenolysis, law, Coordination Complexes, Molecule, [CHIM]Chemical Sciences, Computer Simulation, Electron paramagnetic resonance, ComputingMilieux_MISCELLANEOUS, Crystallography, Molecular Structure, 010405 organic chemistry, Phosphorus, General Chemistry, 0104 chemical sciences, Dication, chemistry, Cyclization, Chemical Sciences, X-Ray, Oxidation-Reduction
Abstract: We report the synthesis and comprehensive study of the electronic structure of a unique series of dinuclear group 5 cyclo-tetraphosphide inverted sandwich complexes. White phosphorus (P4) reacts with niobium(III) and tantalum(III) β-diketiminate (BDI) tert-butylimido complexes to produce the bridging cyclo-P4 phosphide species {[(BDI)(N(t)Bu)M]2(μ-η(3):η(3)P4)} (1, M = Nb; 2, M = Ta) in fair yields. 1 is alternatively synthesized upon hydrogenolysis of (BDI)Nb(N(t)Bu)Me2 in the presence of P4. The trinuclear side product {[(BDI)NbN(t)Bu]3(μ-P12)} (3) is also identified. Protonation of 1 with [HOEt2][B(C6F5)4] does not occur at the phosphide ring but rather involves the BDI ligand to yield {[(BDI(#))Nb(N(t)Bu)]2(μ-η(3):η(3)P4)}[B(C6F5)4]2 (4). The monocation and dication analogues {[(BDI)(N(t)Bu)Nb]2(μ-η(3):η(3)P4)}{B(Ar(F))4}n (5, n = 1; 6, n = 2) are both synthesized by oxidation of 1 with AgBAr(F). DFT calculations were used in combination with EPR and UV-visible spectroscopies to probe the nature of the metal-phosphorus bonding.
Published: 2014

22. Diniobium Inverted Sandwich Complexes with µ-η6:η6-Arene Ligands: Synthesis, Kinetics of Formation, and Electronic Structure

Author: A. L. David Kilcoyne, Stosh A. Kozimor, Thomas L. Gianetti, Stefan G. Minasian, Tolek Tyliszczak, John Arnold, Grégory Nocton, David K. Shuh, Neil C. Tomson, Robert G. Bergman, Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, Laboratoire Hétéroéléments et Coordination (DCPH), École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Chemistry Division, Los Alamos National Laboratory, Los Alamos National Laboratory (LANL), Advanced Light Source [LBNL Berkeley] (ALS), and Lawrence Berkeley National Laboratory [Berkeley] (LBNL)
Subjects: 010405 organic chemistry, Chemistry, Stereochemistry, Kinetics, Cationic polymerization, Protonation, General Chemistry, Electronic structure, 010402 general chemistry, 01 natural sciences, Biochemistry, Small molecule, Catalysis, XANES, 0104 chemical sciences, Crystallography, Colloid and Surface Chemistry, Reactivity (chemistry), [CHIM.COOR]Chemical Sciences/Coordination chemistry, Absorption (chemistry)
Abstract: Monometallic niobium arene complexes [Nb(BDI)(N(t)Bu)(R-C(6)H(5))] (2a: R = H and 2b: R = Me, BDI = N,N'-diisopropylbenzene-β-diketiminate) were synthesized and found to undergo slow conversion into the diniobium inverted arene sandwich complexes [[(BDI)Nb(N(t)Bu)](2)(μ-RC(6)H(5))] (7a: R = H and 7b: R = Me) in solution. The kinetics of this reaction were followed by (1)H NMR spectroscopy and are in agreement with a dissociative mechanism. Compounds 7a-b showed a lack of reactivity toward small molecules, even at elevated temperatures, which is unusual in the chemistry of inverted sandwich complexes. However, protonation of the BDI ligands occurred readily on treatment with [H(OEt(2))][B(C(6)F(5))(4)], resulting in the monoprotonated cationic inverted sandwich complex 8 [[(BDI(#))Nb(N(t)Bu)][(BDI)Nb(N(t)Bu)](μ-C(6)H(5))][B(C(6)F(5))(4)] and the dicationic complex 9 [[(BDI(#))Nb(N(t)Bu)](2)(μ-RC(6)H(5))][B(C(6)F(5))(4)](2) (BDI(#) = (ArNC(Me))(2)CH(2)). NMR, UV-vis, and X-ray absorption near-edge structure (XANES) spectroscopies were used to characterize this unique series of diamagnetic molecules as a means of determining how best to describe the Nb-arene interactions. The X-ray crystal structures, UV-vis spectra, arene (1)H NMR chemical shifts, and large J(CH) coupling constants provide evidence for donation of electron density from the Nb d-orbitals into the antibonding π system of the arene ligands. However, Nb L(3,2)-edge XANES spectra and the lack of sp(3) hybridization of the arene carbons indicate that the Nb → arene donation is not accompanied by an increase in Nb formal oxidation state and suggests that 4d(2) electronic configurations are appropriate to describe the Nb atoms in all four complexes.
Published: 2013
Full Text: View/download PDF

23. A canted antiferromagnetic ordered phase of cyanido-bridged Mn(III)2Re(IV) single-chain magnets

Author: Indrani Bhowmick, Elizabeth A. Hillard, Pierre Dechambenoit, Claude Coulon, Rodolphe Clérac, T. David Harris, Centre de recherches Paul Pascal (CRPP), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Department of Chemistry [Berkeley], University of California [Berkeley], and University of California-University of California
Subjects: Materials science, Single-chain magnets, Condensed matter physics, 010405 organic chemistry, Relaxation (NMR), Metals and Alloys, General Chemistry, Single chain, Magnestism, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 01 natural sciences, Catalysis, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Magnetization, Crystallography, Magnet, Phase (matter), Materials Chemistry, Ceramics and Composites, Antiferromagnetism
Abstract: 3 pages; International audience; A new cyanido-bridged ReIV-MnIII heterometallic 1D system, [MnIII(5-Me-saltmen)]2[ReIVCl4(CN)2] 3CH3CN (1), was designed and structurally characterized. Interchain interactions stabilize a canted antiferromagnetic ordered state below 6.2 K that does not prevent slow relaxation of the magnetization reminiscent of the single-chain magnet properties of the individual chains.
Published: 2012
Full Text: View/download PDF

24. Record ferromagnetic exchange through cyanide and elucidation of the magnetic phase diagram for a Cu(II)Re(IV)(CN)2 chain compound

Author: Jeffrey R. Long, Rodolphe Clérac, Claude Coulon, T. David Harris, Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, Centre de recherches Paul Pascal (CRPP), and Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Phase transition, Condensed matter physics, 010405 organic chemistry, Cyanide, General Chemistry, 010402 general chemistry, 01 natural sciences, Biochemistry, Magnetic susceptibility, Catalysis, 0104 chemical sciences, Cyan-bridged materials, chemistry.chemical_compound, Crystallography, Colloid and Surface Chemistry, Magnetic Phase Diagram, Ferromagnetism, chemistry, Zigzag, Antiferromagnetism, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Ground state, Anisotropy
Abstract: Reaction of the high-magnetic anisotropy building unit [ReCl(4)(CN)(2)](2-) with [Cu(MeCN)(6)](2+) and hydrotris(pyrazol-1-yl)borate (Tp(-)) affords the zigzag chain compound (Bu(4)N)[TpCuReCl(4)(CN)(2)]. Dc magnetic susceptibility measurements reveal the presence of ferromagnetic exchange coupling between Re(IV) and Cu(II) centers along each chain and a fit to the data gives an exchange constant of J/k(B) = +41 K (+29 cm(-1)), representing the strongest ferromagnetic coupling yet observed through cyanide. Below 11.4 K and at applied fields of less than 3600 Oe, the compound undergoes a phase transition to an antiferromagnetic ground state, stemming from weak π-π interchain interactions of strength J(⊥)/k(B) = -1.7 K (-1.2 cm(-1)). This metamagnetic behavior is fully elucidated using both experimental and theoretical methods. In addition, theoretical modeling provides a detailed determination of the local anisotropy tensors corresponding to the [ReCl(4)(CN)(2)](2-) units and demonstrates that the zigzag arrangement of the Re(IV) centers significantly reduces the effective anisotropy of the chain. These results demonstrate the utility of the Re(IV)-CN-Cu(II) linkage and the importance of anisotropic spin orientation in designing strongly coupled systems, which will aid in both the realization of single-chain magnets with higher relaxation barriers and in the construction of high-dimensional cyano-bridged materials exhibiting higher ordering temperatures.
Published: 2010
Full Text: View/download PDF

25. DFT Investigation of the Catalytic Hydromethylation of Olefins by Scandocenes. 2. Influence of the Ansa Ligand on Propene and Isobutene Hydromethylation

Author: Odile Eisenstein, T. Don Tilley, Noémi Barros, Laurent Maron, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), University of California [Berkeley] (UC Berkeley), and University of California (UC)-University of California (UC)
Subjects: 010405 organic chemistry, Ligand, Chemistry, Organic Chemistry, 010402 general chemistry, Photochemistry, 01 natural sciences, 0104 chemical sciences, Catalysis, Inorganic Chemistry, Propene, chemistry.chemical_compound, Computational chemistry, Density functional theory, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Physical and Theoretical Chemistry, ComputingMilieux_MISCELLANEOUS
Abstract: Density functional theory (B3PW91) calculations have been carried out for the hydromethylation of propene and isobutene catalyzed by ansa-Me2Si(C5Me4)2ScCH, as modeled by H2Si(C5H4)2ScCH3. The calc...
Published: 2008
Full Text: View/download PDF

26. Reactions of Monomeric [1,2,4 (Me3C)3C5H2]2CeH and CO with or without H2: An Experimental and Computational Study

Author: Evan L. Werkema, Richard A. Andersen, Laurent Maron, Odile Eisenstein, Department of Chemistry [Berkeley], University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), PICS 3422 Université Berkeley, University of California [Berkeley], University of California-University of California, Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)
Subjects: 010405 organic chemistry, Stereochemistry, Formaldehyde, General Chemistry, 010402 general chemistry, 01 natural sciences, Biochemistry, Toluene, Medicinal chemistry, Catalysis, 0104 chemical sciences, Solvent, Pentane, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, chemistry.chemical_compound, Colloid and Surface Chemistry, Monomer, chemistry, Chemical Sciences, Lone pair, Carbene, Metallocene
Abstract: Addition of CO to [1,2,4-(Me3C)3C5H2]2CeH, Cp'2CeH, in toluene yields the cis (Cp'2Ce)2(mu-OCHCHO), in which the cis enediolate group bridges the two metallocene fragments. The cis enediolate quantitatively isomerizes intramolecularly to the trans-enediolate in C6D6 at 100oC over seven months. When the solvent is pentane, Cp'2Ce(OCH2)CeCp'2 forms, in which the oxomethylene group or the formaldehyde dianion bridges the two metallocene fragments. The cis enediolate is suggested to form by insertion of CO into the Ce-C bond of Cp'2Ce(OCH2)CeCp'2 generating Cp'2CeOCH2COCeCp'2. The stereochemistry of the cis-enediolate is determined by a 1,2-hydrogen shift in the OCH2CO fragment that has the OC(H2) bond anti periplanar relative to the carbene lone pair. The bridging oxomethylene complex reacts with H2, but not with CH4, to give Cp'2CeOMe, which is also the product of the reaction between Cp'2CeH and a mixture of CO and H2. The oxomethylene complex reacts with CO to give the cis enediolate complex. DFT calculations on C5H5 model metallocenes show that the reaction of Cp2CeH with CO and H2 to give Cp2CeOMe is exoergic by 50 kcal mol-1. The net reaction proceeds by a series of elementary reactions that occur after the formyl complex, Cp2Ce(eta-2 CHO), is formed by further reaction with H2. The key point that emerges from the calculated potential energy surface is the bifunctional nature of the metal formyl in which the carbon atom behaves as a donor and acceptor. Replacing H2 by CH4 increases the activation energy barrier by 17 kcal mol-1.
Published: 2007
Full Text: View/download PDF

27. Vacuum ultraviolet photoionization of C3

Author: Majdi Hochlaf, Darcy S. Peterka, Stephen R. Leone, Lionel Poisson, Christophe Nicolas, Musahid Ahmed, Jinian Shu, Laboratoire de Chimie Théorique (LCT), Université Paris-Est Marne-la-Vallée (UPEM), Chemical Sciences Division [LBNL Berkeley] (CSD), Lawrence Berkeley National Laboratory [Berkeley] (LBNL), Department of Physics [Berkeley], University of California [Berkeley], University of California-University of California, Department of Chemistry [Berkeley], University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Department of Chemistry and Physics, University of California (UC), Laboratoire Francis PERRIN (LFP - URA 2453), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and University of California
Subjects: Chemistry, General Chemistry, Photoionization, Configuration interaction, Photon energy, 7. Clean energy, Biochemistry, Catalysis, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Colloid and Surface Chemistry, Ab initio quantum chemistry methods, Excited state, Vibronic spectroscopy, Atomic physics, Ionization energy, Ground state
Abstract: Photoionization efficiency (PIE) curves for C(3) molecules produced by laser ablation are measured from 11.0 to 13.5 eV with tunable vacuum ultraviolet undulator radiation. A step in the PIE curve versus photon energy, obtained with N(2) as the carrier gas, supports the conclusion of very effective cooling of C(3) to its linear (1)Sigma(g)(+) ground state. The second step observed in the PIE curve versus photon energy could be the first experimental evidence of the C(3)(+)((2)Sigma(g)(+)) excited state. The experimental results, complemented by ab initio calculations, suggest a state-to-state vertical ionization energy of 11.70 +/- 0.05 eV between the C(3)(X(1)Sigma(g)(+)) and the C(3)(+)(X(2)Sigma(u)(+)) states. An ionization energy of 11.61 +/- 0.07 eV between the neutral and ionic ground states of C(3) is deduced using the data together with our calculations. Accurate ab initio calculations are performed for both linear and bent geometries on the lowest doublet electronic states of C(3)(+) using Configuration Interaction (CI) approaches and large basis sets. These calculations confirm that C(3)(+) is bent in its electronic ground state, which is separated by a small potential barrier from the (2)Sigma(u)(+) minimum. The gradual increase at the onset of the PIE curve suggests a geometry change between the ground neutral and cationic states. The energies between several doublet states of the ion are theoretically determined to be 0.81, 1.49, and 1.98 eV between the (2)Sigma(u)(+) and the (2)Sigma(g)(+),( 2)Pi(u), (2)Pi(g) excited states of C(3)(+), respectively.
Published: 2006
Full Text: View/download PDF

Catalog

Books, media, physical & digital resources

See catalog results

Searchworks

Select search scope, currently: Articles

Catalog

books, media & more in Jio Institute collections

Articles

journal articles & other e-resources

Refine your results

27 results on '"Department of Chemistry [Berkeley]"'

1. Metallacyclic actinide catalysts for dinitrogen conversion to ammonia and secondary amines

2. Regiospecificity in Ligand-Free Pd-Catalyzed C–H Arylation of Indoles: LiHMDS as Base and Transient Directing Group

3. Synthesis and Structure of Uranium-Silylene Complexes

4. Catalytic Olefin Hydrosilations Mediated by Ruthenium η3-H2Si σ Complexes of Primary and Secondary Silanes

5. A Terminal Fluoride Ligand Generates Axial Magnetic Anisotropy in Dysprosium Complexes

6. Access to Heteroleptic Fluorido-Cyanido Complexes with a Large Magnetic Anisotropy by Fluoride Abstraction

7. [UF6](2-): A molecular hexafluorido actinide(IV) complex with compensating spin and orbital magnetic moments

8. A Uranium Tri-Rhenium Triple Inverse Sandwich Compound

9. The Nature of Secondary Interactions at Electrophilic Metal Sites of Molecular and Silica-Supported Organolutetium Complexes from Solid-State NMR Spectroscopy

10. Heterotetrametallic Re-Zn-Zn-Re Complex Generated by an Anionic Rhenium(I) β-Diketiminate

11. Tristability in a Light-Actuated Single-Molecule Magnet

12. Carbon-Nitrogen Bond Cleavage by a Thorium-NHC-bpy Complex

13. Homoleptic two-coordinate silylamido complexes of chromium(I), manganese(I), and cobalt(I)

14. Multifaceted magnetization dynamics in the mononuclear complex [ReIVCl4(CN)2]2

15. Facile Interconversion of [Cp2(Cl)Hf(SnH3)] and [Cp2(Cl)Hf(μ-H)SnH2]: DFT Investigations of Hafnocene Stannyl Complexes as Masked Stannylenes

16. Bond Activations of PhSiH3 by Cp2SmH: A Mechanistic Investigation by the DFT Method

17. Decamethylytterbocene Complexes of Bipyridines and Diazabutadienes: Multiconfigurational Ground States and Open-Shell Singlet Formation

18. Donor-Promoted 1,2-Hydrogen Migration from Silicon to a Saturated Ruthenium Center and Access to Silaoxiranyl and Silaiminyl Complexes

19. 1,2-Hydrogen Migration to a Saturated Ruthenium Complex via Reversal of Electronic Properties for Tin in a Stannylene-to-Metallostannylene Conversion

20. Cyclometalated N-Heterocyclic Carbene Complexes of Ruthenium for Access to Electron-Rich Silylene Complexes That Bind the Lewis Acids CuOTf and AgOTf

21. Activation of White Phosphorus by Low-Valent Group 5 Complexes: Formation and Reactivity of cyclo-P4 Inverted Sandwich Compounds

22. Diniobium Inverted Sandwich Complexes with µ-η6:η6-Arene Ligands: Synthesis, Kinetics of Formation, and Electronic Structure

23. A canted antiferromagnetic ordered phase of cyanido-bridged Mn(III)2Re(IV) single-chain magnets

24. Record ferromagnetic exchange through cyanide and elucidation of the magnetic phase diagram for a Cu(II)Re(IV)(CN)2 chain compound

25. DFT Investigation of the Catalytic Hydromethylation of Olefins by Scandocenes. 2. Influence of the Ansa Ligand on Propene and Isobutene Hydromethylation

26. Reactions of Monomeric [1,2,4 (Me3C)3C5H2]2CeH and CO with or without H2: An Experimental and Computational Study

27. Vacuum ultraviolet photoionization of C3

Catalog

Searchworks

Select search scope, currently: Articles Catalog books, media & more in Jio Institute collections Articles journal articles & other e-resources

Search

Search Constraints

Refine your results

Search Limiters

Topic

Publication Year Range

Language

Journal

Database

Publisher

27 results on '"Department of Chemistry [Berkeley]"'

Search Results

Catalog

Select search scope, currently: Articles

Catalog

books, media & more in Jio Institute collections

Articles

journal articles & other e-resources