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

1. Selective oxo ligand functionalisation and substitution reactivity in an oxo/catecholate-bridged UIV/UIV Pacman complex

Author: Polly L. Arnold, Laurent Maron, Iskander Douair, Jason B. Love, Bradley E. Cowie, University of Edinburgh, 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), and University of California (UC)-University of California (UC)
Subjects: 010405 organic chemistry, Chemistry, Ligand, General Chemistry, 010402 general chemistry, 01 natural sciences, Medicinal chemistry, Small molecule, 0104 chemical sciences, Chalcogen, Molecular geometry, Nucleophile, Oxidation state, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Bimetallic strip, Lone pair
Abstract: The oxo- and catecholate-bridged UIV/UIV Pacman complex [{(py)UIVOUIV(μ-O2C6H4)(py)}(LA)] A (LA = a macrocyclic "Pacman" ligand; anthracenylene hinge between N4-donor pockets, ethyl substituents on meso-carbon atom of each N4-donor pocket) featuring a bent UIV-O-UIV oxo bridge readily reacts with small molecule substrates to undergo either oxo-atom functionalisation or substitution. Complex A reacts with H2O or MeOH to afford [{(py)UIV(μ-OH)2UIV(μ-O2C6H4)(py)}(LA)] (1) and [{(py)UIV(μ-OH)(μ-OMe)UIV(μ-O2C6H4)(py)}(LA)] (2), respectively, in which the bridging oxo ligand in A is substituted for two bridging hydroxo ligands or one bridging hydroxo and one bridging methoxy ligand, respectively. Alternatively, A reacts with either 0.5 equiv. of S8 or 4 equiv. of Se to provide [{(py)UIV(μ-η2:η2-E2)UIV(μ-O2C6H4)(py)}(LA)] (E = S (3), Se (4)) respectively, in which the [E2]2- ion bridges the two UIV centres. To the best of our knowledge, complex A is the first example of either a d- or f-block bimetallic μ-oxo complex that activates elemental chalcogens. Complex A also reacts with XeF2 or 2 equiv. of Me3SiCl to provide [{(py)UIV(μ-X)2UIV(μ-O2C6H4)(py)}(LA)] (X = F (5), Cl (6)), in which the oxo ligand has been substituted for two bridging halido ligands. Reacting A with either XeF2 or Me3SiCl in the presence of O(Bcat)2 at room temperature forms [{(py)UIV(μ-X)(μ-OBcat)UIV(μ-O2C6H4)(py)}(LA)] (X = F (5A), Cl (6A)), which upon heating to 80 °C is converted to 5 and 6, respectively. In order to probe the importance of the bent UIV-O-UIV motif in A on the observed reactivity, the bis(boroxido)-UIV/UIV complex, [{(py)(pinBO)UIVOUIV(OBpin)(py)}(LA)] (B), featuring a linear UIV-O-UIV bond angle was treated with H2O and Me3SiCl. Complex B reacts with two equiv. of either H2O or Me3SiCl to provide [{(py)HOUIVOUIVOH(py)}(LA)] (7) and [{(py)ClUIVOUIVCl(py)}(LA)] (8), respectively, in which reactions occur preferentially at the boroxido ligands, with the μ-oxo ligand unchanged. The formal UIV oxidation state is retained in all of the products 1-8, and selective reactions at the bridging oxo ligand in A is facilitated by: (1) its highly nucleophilic character which is a result of a non-linear UIV-O-UIV bond angle causing an increase in U-O bond covalency and localisation of the lone pairs of electrons on the μ-oxo group, and (2) the presence of the bridging catecholate ligand, which destabilises a linear oxo-bridging geometry and stabilises the resulting products.
Published: 2020
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2. Understanding the Multiconfigurational Ground and Excited States in Lanthanide Tetrakis Bipyridine Complexes from Experimental and CASSCF Computational Studies

Author: Laurent Maron, Richard A. Andersen, Grégory Nocton, Corwin H. Booth, J. I. Amaro-Estrada, Robert L. Halbach, Department of Chemistry [Berkeley], University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Laboratoire de chimie moléculaire (LCM), École polytechnique (X)-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), Chemical Sciences Division [LBNL Berkeley] (CSD), Lawrence Berkeley National Laboratory [Berkeley] (LBNL), University of California [Berkeley], University of California-University of California, Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), 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)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-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: Lanthanide, 010405 organic chemistry, Electronic structure, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, Magnetic susceptibility, 0104 chemical sciences, Square antiprism, Inorganic Chemistry, Bipyridine, chemistry.chemical_compound, Crystallography, chemistry, Excited state, Molecular orbital, Physical and Theoretical Chemistry, Isostructural
Abstract: International audience; An alternative synthesis for M(κ2-bipy)4 (M = La, Ce) and [Li(thf)4][M(κ2-bipy)4] (M = Tb, Dy) and the crystal structures for M = La, Ce, and Tb are described. The isomorphous and isostructural neutral molecules, M = La and Ce, are polymeric in the solid-state, as are those of M = Sm and Eu, which were reported in earlier work. The polymeric network is built from eight coordinate units whose geometry in all four cases is that of a square prism. The known molecules, M = Yb and Lu, are also polymeric, but the eight coordinate units have dodecahedral geometries. The structure of the anions in the separated ion pair, [Li(thf)4][M(κ2-bipy)4], in which Tb is reported in this work and Lu is known, are monomeric with geometries that are between that of a square antiprism and a dodecahdron. The electronic structure, from CASSCF multireference quantum mechanical calculations, shows that the electronic ground states for M = La and Lu are multiconfigurational spin doublets and those for the M = Ce and Yb are multiconfigurational spin triplets. This is confirmed by magnetic susceptibility studies as a function of temperature that are consistent with the metals (La, Ce, Sm, Tb, Dy, Yb, and Lu) being trivalent, as are the LIII-edge XANES spectra (Ce, Yb), and divalent for Eu. The multiconfigurational nature of the ground states, developed from CASSCF molecular orbital calculations, renders a single Lewis structure and a single reference molecular orbital representation misleading. The results from the multireference calculations are extended to the other lanthanide molecules and are the genesis of a new model for understanding the magnetic properties of these molecules.
Published: 2019
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3. 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
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4. Efficient prediction of nucleus independent chemical shifts for polycyclic aromatic hydrocarbons

Author: Chris J. Pickard, Dimitrios Kilymis, Albert P. Bartók, Céline Merlet, Alexander C. Forse, Centre interuniversitaire de recherche et d'ingenierie des matériaux (CIRIMAT), 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 Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC), Réseau sur le stockage électrochimique de l'énergie (RS2E), Université de Picardie Jules Verne (UPJV)-Institut de Chimie du CNRS (INC)-Aix Marseille Université (AMU)-Université de Pau et des Pays de l'Adour (UPPA)-Université de Nantes (UN)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC), University of Warwick [Coventry], Department of Materials Science and Metallurgy [Cambridge University] (DMSM), University of Cambridge [UK] (CAM), Tohoku University [Sendai], Department of Chemistry [Cambridge, UK], Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, 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), Université de Nantes (UN)-Aix Marseille Université (AMU)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Université de Picardie Jules Verne (UPJV)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Pickard, Christopher [0000-0002-9684-5432], Forse, Alexander [0000-0001-9592-9821], Apollo - University of Cambridge Repository, Centre National de la Recherche Scientifique - CNRS (FRANCE), Collège de France (FRANCE), Ecole Nationale Supérieure de Chimie de Paris - ENSCP (FRANCE), Ecole Nationale Supérieure de Chimie de Montpellier - ENSCM (FRANCE), Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Institut polytechnique de Grenoble (FRANCE), Sorbonne Université (FRANCE), University of Cambridge (UNITED KINGDOM), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Université de Nantes (FRANCE), Université de Picardie Jules Verne (FRANCE), University of Warwick (UNITED KINGDOM), Science and Technology Facilities Council - STFC (UNITED KINGDOM), Tohoku University (JAPAN), University of California - UC Berkeley (USA), Université de Pau et des Pays de l'Adour - UPPA (FRANCE), Université de Grenoble (FRANCE), Université de Haute Alsace - UHA (FRANCE), and Université de Montpellier (FRANCE)
Subjects: Energie électrique, Materials science, Nuclear Magnetic Resonance (NMR), Matériaux, Complex system, General Physics and Astronomy, FOS: Physical sciences, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, law.invention, law, Physics - Chemical Physics, Molecule, QD, Physical and Theoretical Chemistry, Chemical Physics (physics.chem-ph), Condensed Matter - Materials Science, Graphene, Chemical shift, Materials Science (cond-mat.mtrl-sci), Carbon-13 NMR, 021001 nanoscience & nanotechnology, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Dipole, Polycyclic aromatic hydrocarbons (PAHs), Chemical physics, Density functional theory, 0210 nano-technology, Order of magnitude
Abstract: International audience; Nuclear Magnetic Resonance (NMR) is one of the most powerful experimental techniques to characterize the structure of molecules and confined liquids. Nevertheless, the complexity of the systems under investigation usually requires complementary computational studies to interpret the NMR results. In this work we focus on polycyclic aromatic hydrocarbons (PAHs), an important class of organic molecules which have been commonly used as simple analogues for the spectroscopic properties of more complex systems, such as porous disordered carbons. We use Density Functional Theory (DFT) to calculate 13C chemical shifts and Nucleus Independent Chemical Shifts (NICS) for 34 PAHs. The results show a clear molecular size dependence of the two quantities, as well as the convergence of the 13C NMR shifts towards the values observed for graphene. We then present two computationally cheap models for the prediction of NICS in simple PAHs. We show that while a simple dipolar model fails to produce accurate values, a perturbative tight-binding approach can be successfully applied for the prediction of NICS in this series of molecules, including some non-planar ones containing 5-and 7-membered rings. This model, one to two orders of magnitudes faster than DFT calculations, is very promising and can be further refined in order to study more complex systems.
Published: 2020
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5. Uranium Metallocene Azides, Isocyanates, and Their Borane-Capped Lewis Adducts

Author: John Arnold, Michael A. Boreen, Trevor D. Lohrey, Stephan Hohloch, Laurent Maron, Fabian A. Watt, Karl N. McCabe, 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 Paderborn, Freie Universität Berlin, and Universität Innsbruck [Innsbruck]
Subjects: 010405 organic chemistry, Ligand, Borane, 010402 general chemistry, Cyanate, 01 natural sciences, Medicinal chemistry, Isocyanate, 0104 chemical sciences, Inorganic Chemistry, chemistry.chemical_compound, chemistry, Cyclopentadienyl complex, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Azide, Physical and Theoretical Chemistry, Linkage isomerism, Metallocene
Abstract: Uranium(IV) metallocene complexes (CpiPr4)2U(N3)2 (1-N3), (CpiPr)2U(NCO)2 (1-NCO), and (CpiPr4)2U(OTf)2 (1-OTf) containing the bulky CpiPr4 ligand (CpiPr4 = tetra(isopropyl)cyclopentadienyl) were prepared directly from reactions between (CpiPr4)2UI2 or (CpiPr4)2UI and corresponding pseudohalide salts. The mixed-ligand complex (CpiPr4)2U(N3)(OTf) (1-N3-OTf) was isolated after heating a 1:1 mixture of 1-N3 and 1-OTf. The coordination of 1 equiv B(C6F5)3 to 1-N3 produced the borane-capped azide (CpiPr4)2U(N3)[(μ-η1:η1-N3)B(C6F5)3] (2-N3), while the reaction of 1 equiv B(C6F5)3 with 1-NCO yielded (CpiPr4)2U(NCO)[(μ-η1:η1-OCN)B(C6F5)3] (2-NCO) in which the borane-capped cyanate ligand had rearranged to become O-bound to uranium. The reaction of (CpiPr4)2UI and NaOCN led to the isolation of the uranium(III) cyanate-bridged "molecular square" [(CpiPr4)2U(μ-η1:η1-OCN)]4 (3-OCN). Cyclic voltammetry and UV-vis spectroscopy revealed small differences in the electronic properties between azide and isocyanate complexes, while X-ray crystallography showed nearly identical solid-state structures, with the most notable difference being the geometry of borane coordination to the azide in 2-N3 versus the cyanate in 2-NCO. Reactivity studies comparing 3-OCN to the azide analogue [(CpiPr4)2U(μ-η1:η1-N3)]4 (3-N3) demonstrated significant differences in the chemistry of cyanates and azides with trivalent uranium. A computational analysis of 1-NCO, 1-N3, 2-NCO, and 2-N3 has provided a basis for understanding the energetic preference for specific linkage isomers and the effect of the B(C6F5)3 coordination on the bonding between uranium, azide, and isocyanate ligands.
Published: 2020
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6. 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
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7. 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
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8. Chemical structure and bonding in a thorium(<scp>iii</scp>)–aluminum heterobimetallic complex

Author: Laurent Maron, Stefan G. Minasian, R. David Britt, Alexandra C. Brown, David K. Shuh, John Arnold, Alison B. Altman, Trevor D. Lohrey, Guodong Rao, 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), Earth Sciences Division (ESD), Lawrence Berkeley National Lab, 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], NIH [1R35GM126961-01], Department of Energy National Nuclear Security Administration through the Nuclear Science and Security Consortium [DE-NA0003180, DE-NA0000979], U.S. DOE Office of Science User Facility [DE-AC02-05CH11231], DOE Integrated University Program Fellowships at the University of California, Berkeley, and Goldwater Foundation
Subjects: 010405 organic chemistry, Chemistry, General Chemistry, Electronic structure, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, 3. Good health, law.invention, Delocalized electron, Crystallography, Unpaired electron, Transition metal, law, Chemical Sciences, Molecule, Density functional theory, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Electron paramagnetic resonance, Valence electron
Abstract: We describe the syntheses of [Th(iii)]–[Al] and [U(iii)]–[Al] bimetallics that demonstrate An→Al interactions where the actinide behaves as an electron donor., Thorium sits at a unique position on the periodic table. On one hand, there is little evidence that its 5f orbitals engage in bonding as they do in other early actinides; on the other hand, its chemistry is distinct from Lewis acidic transition metals. To gain insight into the underlying electronic structure of Th and develop trends across the actinide series, it is useful to study Th(iii) and Th(ii) systems with valence electrons that may engage in non-electrostatic metal–ligand interactions, although only a handful of such systems are known. To expand the range of low-valent compounds and gain deeper insight into Th electronic structure, we targeted actinide bimetallic complexes containing metal–metal bonds. Herein, we report the syntheses of Th–Al bimetallics from reactions between a di-tert-butylcyclopentadienyl supported Th(iv) dihalide (Cp‡2ThCl2) and an anionic aluminum hydride salt [K(H3AlC(SiMe3)3) (1)]. Reduction of the [Th(iv)](Cl)–[Al] product resulted in a [Th(iii)]–[Al] complex [Cp‡2Th(μ-H3)AlC(SiMe3)3 (4)]. The U(iii) analogue [Cp‡2U(μ-H3)AlC(SiMe3)3 (5)] could be synthesized directly from a U(iii) halide starting material. Electron paramagnetic resonance studies on 4 demonstrate hyperfine interactions between the unpaired electron and the Al atom indicative of spin density delocalization from the Th metal center to the Al. Density functional theory and atom in molecules calculations confirmed the presence of An→Al interactions in 4 and 5, which represents the first examples of An→M interactions where the actinide behaves as an electron donor.
Published: 2018
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9. 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
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10. 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
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11. Metallacyclic actinide catalysts for dinitrogen conversion to ammonia and secondary amines (vol 15, pg 312, 2020)

Author: Arnold, Polly L., Ochiai, Tatsumi, Lam, Francis Y. T., Kelly, Rory P., Seymour, Megan L., Maron, Laurent, Department of Chemistry [Berkeley], University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), University of Edinburgh, 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: [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph]
Published: 2020
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12. 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
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13. Field-dependent ionic conductivities from generalized fluctuation-dissipation relations

Author: Chloe Ya Gao, Dominika Lesnicki, Benjamin Rotenberg, David T. Limmer, PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, Liquides Ioniques et Interfaces Chargées (LI2C), Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Lawrence Berkeley National Laboratory [Berkeley] (LBNL)
Subjects: General Physics, Materials science, FOS: Physical sciences, General Physics and Astronomy, Ionic bonding, Thermodynamics, Non-equilibrium thermodynamics, Molecular dynamics, Conductivity, 01 natural sciences, Mathematical Sciences, Engineering, Electric field, 0103 physical sciences, Electrical conductivity, Ionic conductivity, 010306 general physics, Condensed Matter - Statistical Mechanics, [PHYS]Physics [physics], Statistical Mechanics (cond-mat.stat-mech), Nonequilibrium fluctuations, Strong electrolyte, Condensed Matter::Soft Condensed Matter, Ionic strength, Physical Sciences, Nonequilibrium systems
Abstract: We derive a relationship for the electric field dependent ionic conductivity in terms of fluctuations of time integrated microscopic variables. We demonstrate this formalism with molecular dynamics simulations of solutions of differing ionic strength with implicit solvent conditions and molten salts. These calculations are aided by a novel nonequilibrium statistical reweighting scheme that allows for the conductivity to be computed as a continuous function of the applied field. In strong electrolytes, we find the fluctuations of the ionic current are Gaussian and subsequently the conductivity is constant with applied field. In weaker electrolytes and molten salts, we find the fluctuations of the ionic current are strongly non-Gaussian and the conductivity increases with applied field. This nonlinear behavior, known phenomenologically for dilute electrolytes as the Onsager-Wien effect, is general and results from the suppression of ionic correlations at large applied fields, as we elucidate through both dynamic and static correlations within nonequilibrium steady-states., 6 pages, 3 figures
Published: 2019
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14. Envisioning the next decade of Galactic Center science: a laboratory for the study of the physics and astrophysics of supermassive black holes

Author: Do, Tuan, Ghez, Andrea, Lu, Jessica R., Morris, Mark, Hosek Jr., Matthew, Hees, Aurelien, Naoz, Smadar, Ciurlo, Anna, Armitage, Philip J., Beaton, Rachael L, Becklin, Eric, Bellini, Andrea, Bentley, Rory O., Bland-Hawthorn, Joss, Chakrabarti, Sukanya, Chen, Zhuo, Chu, Devin S., Dehghanfar, Arezu, Gammie, Charles F., Gautam, Abhimat K., Genzel, Reinhard, Greene, Jenny, Haggard, Daryl, Hora, Joseph, Kerzendorf, Wolfgang E., Libralato, Mattia, Nishiyama, Shogo, O'Neil, Kelly Kosmo, Ozel, Feryal, Paumard, Thibaut, Perets, Hagai B., Psaltis, Dimitrios, Quataert, Eliot, Ramirez-Ruiz, Enrico, Rich, R Michael, Rasio, Fred, Sakai, Shoko, Schoedel, Rainer, Smith, Howard, Weinberg, Nevin N., Witzel, Gunther, Department of Physics and Astronomy [UCLA, Los Angeles], University of California [Los Angeles] (UCLA), University of California-University of California, Department of Chemistry [Berkeley], University of California [Berkeley], Systèmes de Référence Temps Espace (SYRTE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Observatoire de Paris - Site de Meudon (OBSPM), Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), Anglo-Australian Observatory (AAO), Shandong Provincial Key Laboratory of Plant Stress, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Max Planck Institute for Extraterrestrial Physics (MPE), Max-Planck-Gesellschaft, Institut d'Astrophysique de Paris (IAP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and UCLA
Subjects: Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Astrophysics::Galaxy Astrophysics
Abstract: 9 pages, 4 figures, submitted for Astro2020 White Paper; As the closest example of a galactic nucleus, the Galactic center (GC) presents an exquisite laboratory for learning about supermassive black holes (SMBH) and their environment. We describe several exciting new research directions that, over the next 10 years, hold the potential to answer some of the biggest scientific questions raised in recent decades: Is General Relativity (GR) the correct description for supermassive black holes? What is the nature of star formation in extreme environments? How do stars and compact objects dynamically interact with the supermassive black hole? What physical processes drive gas accretion in low-luminosity black holes? We describe how the high sensitivity, angular resolution, and astrometric precision offered by the next generation of large ground-based telescopes with adaptive optics will help us answer these questions. First, it will be possible to obtain precision measurements of stellar orbits in the Galaxy's central potential, providing both tests of GR in the unexplored regime near a SMBH and measurements of the extended dark matter distribution that is predicted to exist at the GC. Second, we will probe stellar populations at the GC to significantly lower masses than are possible today, down to brown dwarfs. Their structure and dynamics will provide an unprecedented view of the stellar cusp around the SMBH and will distinguish between models of star formation in this extreme environment. This increase in depth will also allow us to measure the currently unknown population of compact remnants at the GC by observing their effects on luminous sources. Third, uncertainties on the mass of and distance to the SMBH can be improved by a factor of $\sim$10. Finally, we can also study the near-infrared accretion onto the black hole at unprecedented sensitivity and time resolution, which can reveal the underlying physics of black hole accretion.
Published: 2019

15. [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
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16. Keck Observations Confirm a Super-Jupiter Planet Orbiting M-dwarf OGLE-2005-BLG-071L

Author: Calen B. Henderson, J.-P. Beaulieu, Jessica R. Lu, Sean K. Terry, Aikaterini Vandorou, J. B. Marquette, Naoki Koshimoto, J. W. Blackman, Andrew A. Cole, David P. Bennett, Andrzej Udalski, Clément Ranc, Aparna Bhattacharya, Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Department of Chemistry [Berkeley], University of California [Berkeley], and University of California-University of California
Subjects: Proper motion, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, 01 natural sciences, Jupiter, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Very Large Telescope, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Light curve, Exoplanet, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Planetary mass, Astrophysics - Earth and Planetary Astrophysics
Abstract: We present adaptive optics imaging from the NIRC2 instrument on the Keck-2 telescope that resolves the exoplanet host (and lens) star as it separates from the brighter source star. These observations yield the $K$-band brightness of the lens and planetary host star, as well as the lens-source relative proper motion, $��_{\rm rel,H}$. in the heliocentric reference frame. The $��_{\rm rel,H}$ measurement allows determination of the microlensing parallax vector, $��_E$, which had only a single component determined by the microlensing light curve. The combined measurements of $��_{\rm rel,H}$ and $K_L$ provide the masses of the host stat, $M_{\rm host} = 0.426\pm 0.037 M_\odot$, and planet, $m_p = 3.27 \pm 0.32 M_{\rm Jup}$ with a projected separation of $3.4\pm 0.5\,$AU. This confirms the tentative conclusion of a previous paper (Dong et al. 2009) that this super-Jupiter mass planet, OGLE-2005-BLG-071Lb, orbits an M-dwarf. Such planets are predicted to be rare by the core accretion theory and have been difficult to find with other methods, but there are two such planets with firm mass measurements from microlensing, and an additional 11 planetary microlens events with host mass estimates $< 0.5M_\odot$ and planet mass estimates $> 2$ Jupiter masses that could be confirmed by high angular follow-up observations. We also point out that OGLE-2005-BLG-071L has separated far enough from its host star that it should be possible to measure the host star metallicity withspectra from a high angular resolution telescope such as Keck, the VLT, the Hubble Space Telescope or the James Webb Space Telescope., accepted by AJ
Published: 2019
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17. 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
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18. 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
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19. A linear cobalt(II) complex with maximal orbital angular momentum from a non-Aufbau ground state

Author: Jacob Overgaard, Emil Damgaard-Møller, I. Crassee, Joris van Slageren, Mauro Perfetti, Frank Neese, Philip C. Bunting, Mihail Atanasov, Jeffrey R. Long, Milan Orlita, Max Planck Institute for Chemical Energy Conversion, Max-Planck-Gesellschaft, Institut für Physikalische Chemie, Universität Stuttgart [Stuttgart], Laboratoire national des champs magnétiques intenses - Grenoble (LNCMI-G ), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), 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)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Centre for Materials Crystallography, Aarhus University [Aarhus], Physikalisches Institut [Stuttgart] (Pfaffenwaldring 57, D–70550 Stuttgart, Germany), Max-Planck-Institut für Chemische Energiekonversion (MPI-CEC), University of California [Berkeley], University of California, Laboratoire des champs magnétiques intenses (LCMI-GHMFL), Centre National de la Recherche Scientifique (CNRS), Department of Chemistry [Berkeley], and University of California-University of California
Subjects: Physics, Ligand field theory, Angular momentum, Multidisciplinary, 010405 organic chemistry, Magnetism, 010402 general chemistry, 01 natural sciences, Molecular physics, Magnetic susceptibility, 0104 chemical sciences, Magnetic anisotropy, Atomic orbital, [CHIM]Chemical Sciences, Electron configuration, Ground state, ComputingMilieux_MISCELLANEOUS
Abstract: INTRODUCTION The magnetic properties of a single metal center are determined by a combination of its total spin S and orbital angular momentum L . Orbital angular momentum gives rise to magnetic anisotropy, an essential property for applications such as information storage and high-coercivity magnets. Unquenched L arises from an odd number of electrons in degenerate orbitals and is typically observed only for free ions, as well as for complexes of the f elements. For the majority of transition metal ions, however, orbital angular momentum is quenched by the ligand field, which removes the requisite orbital degeneracies. Maximal L for a transition metal ( L = 3) would require an odd number of electrons in two sets of degenerate orbitals. Such a species would entail a non-Aufbau configuration, wherein the electrons do not fill the d orbitals in the usual order of lowest to highest in energy, and likely exhibit a large magnetic anisotropy. RATIONALE Previous efforts have identified the utility of linear coordination environments for isolating iron complexes with unquenched orbital angular momentum and large magnetic anisotropies. Crucially, transition metals in this environment are unaffected by Jahn-Teller distortions that would otherwise remove orbital degeneracies in the case of partially filled d orbitals. Separately, cobalt atoms deposited on a MgO surface—for which one-coordination of the metal is achieved, provided a vacuum is maintained—were shown to have L = 3, giving rise to near-maximal magnetic anisotropy. Calculations on the hypothetical linear molecule Co(C(SiMe 3 ) 3 ) 2 (where Me is methyl) also predicted that this system would possess a ground state with L = 3. Empirically, maximal L in a transition metal complex thus requires both a linear coordination environment and a sufficiently weak ligand field strength to allow for non-Aufbau electron filling. RESULTS The strongly reducing nature of the carbanion ligand hinders isolation of dialkyl cobalt(II) complexes. However, reducing the basicity of the central carbanion through the use of electron-withdrawing aryloxide groups allowed for the synthesis of the dialkyl cobalt(II) complex Co(C(SiMe 2 ONaph) 3 ) 2 , where Naph is a naphthyl group. Ab initio calculations on this complex predict a ground state with S = 3 / 2 , L = 3, and J = 9 / 2 arising from the non-Aufbau electron configuration (d x 2 –y 2 , d xy ) 3 (d xz , d yz ) 3 (d z 2 ) 1 . Much as for lanthanide complexes, the ligand field is sufficiently weak that interelectron repulsion and spin-orbit coupling play the key roles in determining the electronic ground state. dc magnetic susceptibility measurements reveal a well-isolated M J = ± 9 / 2 ground state, and simulations of the magnetic data from the calculations are in good agreement with the experimental data. Variable-field far-infrared (FIR) spectroscopy shows a magnetically active excited state at 450 cm −1 that, in combination with calculations and variable-temperature ac magnetic susceptibility experiments, is assigned to the M J = ± 7 / 2 state. Modeling of experimental charge density maps also suggests a d-orbital filling with equally occupied (d x 2 –y 2 , d xy ), and (d xz , d yz ) orbital sets. As a consequence of its large orbital angular momentum, the molecule exhibits slow magnetic relaxation and, in a magnetically dilute sample, a coercive field of 600 Oe at 1.8 K. CONCLUSION Isolation of Co(C(SiMe 2 ONaph) 3 ) 2 illustrates how an extreme coordination environment can confer an f-element–like electronic structure on a transition metal complex. The non-Aufbau ground state enables realization of maximal orbital angular momentum and magnetic anisotropy near the physical limit for a 3d metal. In this respect, the linear L–Co–L motif may prove useful in the design of new materials with high magnetic coercivity.
Published: 2018
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20. Reusable Enzymatic Fiber Mats for Neurotoxin Remediation in Water

Author: DelRe, Christopher, Huang, Charley, Li, Tim, Dennis, Patrick, Drockenmuller, Eric, Xu, Ting, Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, Ingénierie des Matériaux Polymères (IMP), 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)-Université Jean Monnet [Saint-Étienne] (UJM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Univ Calif Berkeley, Dept Mat Sci & Engn
Subjects: [CHIM.POLY]Chemical Sciences/Polymers, [CHIM.MATE]Chemical Sciences/Material chemistry, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2018

21. Formation of the layered conductive magnet CrCl2(pyrazine)2 through redox-active coordination chemistry

Author: Jeffrey R. Long, Andrei Rogalev, Sebastian E. Reyes-Lillo, Jeffrey B. Neaton, Laura Voigt, Mathieu Rouzières, Michael L. Aubrey, Kasper S. Pedersen, Rodolphe Clérac, Zhongshan Li, Fabrice Wilhelm, Panagiota S. Perlepe, Daniel N. Woodruff, Dumitru Samohvalov, Anders Reinholdt, Kasper A. Borup, Technical University of Denmark [Lyngby] (DTU), Centre de Recherche Paul Pascal (CRPP), Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), 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 [Berkeley], University of California [Berkeley], University of California-University of California, Department of Chemistry, University of Oxford, Molecular Fondry [LBNL Berkeley], Lawrence Berkeley National Laboratory [Berkeley] (LBNL), Department of Physics [Berkeley], Departamento de Ciencias Fisicas, Universidad Andres Bello, Department of Chemistry [Copenhagen], Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Department of Chemistry, Technical University of Denmark, Lyngby, Centre for Storage Ring Facilities [Aarhus] (ISA), Aarhus University [Aarhus], Center for Materials Crystallography (CMC), Interdisciplinary Nanoscience Center (iNANO), European Synchrotron Radiation Facility (ESRF), University of California, Kavli Energy Nanosciences Institute at Berkeley, Department of Chemical & Biomolecular Engineering [Berkeley] (CBE), Materials Science Division [LBNL Berkeley], Departamento de Ciencias Fisicas [Santiago de Chile], and Universidad Andrés Bello [Santiago] (UNAB)
Subjects: Pyrazine, General Chemical Engineering, 02 engineering and technology, Conductivity, 010402 general chemistry, 01 natural sciences, law.invention, Coordination complex, chemistry.chemical_compound, Paramagnetism, Ferrimagnetism, law, chemistry.chemical_classification, Spintronics, Graphene, Ligand, Organic Chemistry, General Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 3. Good health, 0104 chemical sciences, chemistry, Chemical physics, Chemical Sciences, 0210 nano-technology
Abstract: The unique properties of graphene, transition-metal dichalcogenides and other two-dimensional (2D) materials have boosted interest in layered coordination solids. In particular, 2D materials that behave as both conductors and magnets could find applications in quantum magnetoelectronics and spintronics. Here, we report the synthesis of CrCl2(pyrazine)2, an air-stable layered solid, by reaction of CrCl2 with pyrazine (pyz). This compound displays a ferrimagnetic order below ∼55 K, reflecting the presence of strong magnetic interactions. Electrical conductivity measurements demonstrate that CrCl2(pyz)2 reaches a conductivity of 32 mS cm–1 at room temperature, which operates through a 2D hopping-based transport mechanism. These properties are induced by the redox-activity of the pyrazine ligand, which leads to a smearing of the Cr 3d and pyrazine π states. We suggest that the combination of redox-active ligands and reducing paramagnetic metal ions represents a general approach towards tuneable 2D materials that consist of charge-neutral layers and exhibit both long-range magnetic order and high electronic conductivity.
Published: 2018
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22. Enhanced reactivity of fluorine with para-hydrogen in cold interstellar clouds by resonance-induced quantum tunnelling

Author: Zhigang Sun, Jun Chen, Dong H. Zhang, François Lique, Long Huang, Millard H. Alexander, Daniel M. Neumark, Tao Wang, Tiangang Yang, Dongxu Dai, Chunlei Xiao, Xueming Yang, Laboratoire Ondes et Milieux Complexes (LOMC), Centre National de la Recherche Scientifique (CNRS)-Université Le Havre Normandie (ULH), Normandie Université (NU)-Normandie Université (NU), Department of Chemistry [Berkeley], University of California [Berkeley], and University of California-University of California
Subjects: [PHYS]Physics [physics], 010405 organic chemistry, Scattering, Chemistry, General Chemical Engineering, Interstellar cloud, General Chemistry, 010402 general chemistry, Spin isomers of hydrogen, 7. Clean energy, 01 natural sciences, Molecular physics, Resonance (particle physics), 0104 chemical sciences, Reaction rate, X-ray photoelectron spectroscopy, 13. Climate action, Reactivity (chemistry), Quantum tunnelling, ComputingMilieux_MISCELLANEOUS
Abstract: Chemical reactions are important in the evolution of low-temperature interstellar clouds, where the quantum tunnelling effect becomes significant. The F + para-H2 → HF + H reaction, which has a significant barrier of 1.8 kcal mol−1, is an important source of HF in interstellar clouds; however, the dynamics of this quantum-tunnelling-induced reactivity at low temperature is unknown. Here, we show that this quantum tunnelling is caused by a post-barrier resonance state. Quantum-state-resolved crossed-beam scattering measurements reveal that this resonance state has a collision energy of ~5 meV and a lifetime of ~80 fs, which are in excellent agreement with a recent anion photoelectron spectroscopic study. Accurate quantum reactive scattering calculations on the new iCSZ-LWAL potential energy surfaces provides a detailed explanation of the experimental results. The reaction rate for this system was also theoretically determined accurately at temperatures as low as 1 K. The F + para-H2 → HF + H reaction is an important source of HF in interstellar clouds; however, its unusually high rate and its dynamics at low temperature are not fully understood. Now, quantum-state resolved crossed-beam scattering measurements and anion photoelectron spectroscopy have revealed that this reactivity is caused by a resonance-enhanced tunnelling effect involving a post-barrier resonance state.
Published: 2018
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23. Off-axis point spread function characterization in laser guide star adaptive optics systems

Author: Etsuko Mieda, Jean-Pierre Véran, Carlos Correia, Olivier Beltramo-Martin, G. Witzel, Benoit Neichel, Jessica R. Lu, Thierry Fusco, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Subaru Telescope, National Astronomical Observatory of Japan (NAOJ), DOTA, ONERA, Université Paris Saclay (COmUE) [Châtillon], ONERA-Université Paris Saclay (COmUE), Department of Physics and Astronomy [UCLA, Los Angeles], University of California [Los Angeles] (UCLA), University of California-University of California, Department of Chemistry [Berkeley], University of California [Berkeley], National Research Council (Victoria, Canada), University of California (UC)-University of California (UC), and University of California [Berkeley] (UC Berkeley)
Subjects: Point spread function, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], instrumentation: adaptive optics, 01 natural sciences, methods: analytical, law.invention, Fraction of variance unexplained, 010309 optics, Photometry (optics), Telescope, Optics, law, 0103 physical sciences, Adaptive optics, 010303 astronomy & astrophysics, Physics, business.industry, Astronomy and Astrophysics, Astrometry, Laser, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], methods: data analysis, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Laser guide star, Space and Planetary Science, business, atmospheric effects
Abstract: Adaptive optics (AO) restore the angular resolution of ground-based telescopes, but at the cost of delivering a time- and space-varying point spread function (PSF) with a complex shape. PSF knowledge is crucial for breaking existing limits on the measured accuracy of photometry and astrometry in science observations. In this paper, we concentrate our analyses of the anisoplanatism signature only on to the PSF. For large-field observations (20 arcmin) with single-conjugated AO, PSFs are strongly elongated due to anisoplanatism that manifests itself as three different terms for laser guide star (LGS) systems: angular, focal and tilt anisoplanatism. First, we propose a generalized model that relies on a point-wise decomposition of the phase and encompasses the non-stationarity of LGS systems. We demonstrate that it is more accurate and less computationally demanding than existing models: it agrees with end-to-end physical-optics simulations to within 0.1 per cent of PSF measurables, such as the Strehl ratio, FWHM and the fraction of variance unexplained (FVU). Secondly, we study off-axis PSF modelling with respect to the C2n(h) Cn2(h) profile (heights and fractional weights). For 10-mclass telescopes, PSF morphology is estimated at the 1 per cent level as long as we model the atmosphere with at least seven layers, whose heights and weights are known with precisions of 200 m and 10 per cent, respectively. As a verification test, we used the Canada’s National Research Council – Herzberg NFIRAOS Optical Simulator (HeNOS) testbed data, featuring four lasers. We highlight the capability of retrieving off-axis PSF characteristics within 10 per cent of the FVU, which complies with the expected range from the sensitivity analysis. Our new off-axis PSF modelling method lays the groundwork for testing on-sky in the near future.
Published: 2018
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24. NMR chemical shift analysis decodes olefin oligo- and polymerization activity of d0 group 4 metal complexes

Author: Satoru Shirase, Keishi Yamamoto, Christopher P. Gordon, Richard A. Andersen, Christophe Copéret, Odile Eisenstein, Department of Chemistry and Applied Biosciences [ETH Zürich] (D-CHAB), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, 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), and Laboratory of Inorganic Chemistry
Subjects: chemistry.chemical_classification, Agostic interaction, Olefin fiber, Multidisciplinary, 010405 organic chemistry, Chemical shift, Nuclear magnetic resonance spectroscopy, Carbon-13 NMR, 010402 general chemistry, 01 natural sciences, Olefin polymerization, olefin oligomerization, NMR Spectroscopy, chemical shift tensor analysis, frontier molecular orbitals, 0104 chemical sciences, Crystallography, chemistry, Polymerization, PNAS Plus, [CHIM]Chemical Sciences, Molecular orbital, Alkyl, ComputingMilieux_MISCELLANEOUS
Abstract: d0 metal-alkyl complexes (M = Ti, Zr, and Hf) show specific activity and selectivity in olefin polymerization and oligomerization depending on their ligand set and charge. Here, we show by a combined experimental and computational study that the 13C NMR chemical shift tensors of the α-carbon of metal alkyls that undergo olefin insertion signal the presence of partial alkylidene character in the metal–carbon bond, which facilitates this reaction. The alkylidene character is traced back to the π-donating interaction of a filled orbital on the alkyl group with an empty low-lying metal d-orbital of appropriate symmetry. This molecular orbital picture establishes a connection between olefin insertion into a metal-alkyl bond and olefin metathesis and a close link between the Cossee–Arlmann and Green–Rooney polymerization mechanisms. The 13C NMR chemical shifts, the α-H agostic interaction, and the low activation barrier of ethylene insertion are, therefore, the results of the same orbital interactions, thus establishing chemical shift tensors as a descriptor for olefin insertion.
Published: 2018
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25. Cerium Tetrakis(tropolonate) and Cerium Tetrakis(acetylacetonate) Are Not Diamagnetic but Temperature-Independent Paramagnets

Author: Halbach, Robert L, Nocton, Grégory, Booth, Corwin H, Maron, Laurent, Andersen, Richard A, Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, Laboratoire de chimie moléculaire (LCM), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Chemical Sciences Division [LBNL Berkeley] (CSD), Lawrence Berkeley National Laboratory [Berkeley] (LBNL), 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)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-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), École polytechnique (X)-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), and Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Inorganic Chemistry, Inorganic & Nuclear Chemistry, Chemical Engineering, [CHIM.OTHE]Chemical Sciences/Other, Other Chemical Sciences, Physical Chemistry, ComputingMilieux_MISCELLANEOUS, Physical Chemistry (incl. Structural)
Abstract: © 2018 American Chemical Society. A new synthesis of cerium tetrakis(tropolonate), Ce(trop)4, where trop is deprotonated 2-hydroxy-2,4,6-cycloheptatrienone) or Ce(O2C7H5)4, is developed that results in dark-purple crystals whose X-ray crystal structure shows that the geometry of the eight-coordinate compound closely resembles a D2ddodecahedron, based on shape parameters. The magnetic susceptibility as a function of the temperature (4-300 K) shows that it is a temperature-independent paramagnet, χ = 1.2(3) × 10-4emu/mol, and the LIII-edge X-ray absorption near-edge structure spectrum shows that the molecule is multiconfigurational, comprised of a f1:f0configuration mixture in a 50:50 ratio. Ce(acac)4and Ce(tmtaa)2(where acac is acetylacetonate and tmtaaH2is tetramethyldibenzotetraaza[14]annulene) have similar physical properties, as does the solid-state compound CeO2. The concept is advanced that trop-, acac-, tmtaa2-, cot2-, and O2-are redox-active ligands that function as electron donors, rendering the classification of these compounds according to their oxidation numbers misleading because their magnetic susceptibilities, χ, are positive and their effective magnetic moments, μeff, lie in the range of 0.1-0.7 μBat 300 K.
Published: 2018
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26. 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
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27. N–N bond cleavage in a nitrous oxide–NHC adduct promoted by a PNP pincer cobalt(I) complex

Author: Clément Camp, Kay Severin, Lara C. E. Naested, John Arnold, Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, and Ecole Polytech Fed Lausanne, Inst Sci & Ingn Chim, CH-1015 Lausanne, Switzerland
Subjects: inorganic chemicals, 010405 organic chemistry, Chemistry, Imine, chemistry.chemical_element, equipment and supplies, 010402 general chemistry, Photochemistry, 01 natural sciences, Medicinal chemistry, 0104 chemical sciences, Adduct, Pincer movement, Inorganic Chemistry, chemistry.chemical_compound, Materials Chemistry, [CHIM]Chemical Sciences, Reactivity (chemistry), Physical and Theoretical Chemistry, Pincer ligand, Cobalt, Carbene, ComputingMilieux_MISCELLANEOUS, Bond cleavage
Abstract: The reactivity of a PNP cobalt(I) complex towards the nitrous oxide N-heterocyclic carbene adduct (NHC-N2O) was explored. Several products were isolated including the cobalt nitrosyl complex (HPNP)Co(NO) (1) and the NHC-derived imine NHC=NH (2). This study provides a rare example of metal-mediated rupture of the N-N bond in a nitrous oxide derivative, a route that could be used to generate late-metal nitrosyls.
Published: 2016
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28. Metal alkyls programmed to generate metal alkylidenes by α-H abstraction: prognosis from NMR chemical shift

Author: Keith Searles, Keishi Yamamoto, Christophe Copéret, Richard A. Andersen, Odile Eisenstein, Satoru Shirase, Christopher P. Gordon, Department of Chemistry and Applied Biosciences [ETH Zürich] (D-CHAB), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Department of Chemistry - Graduate School of Engineering Science, Osaka University, Graduate School of Engineering Science, Osaka University, Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, 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), Hylleraas Centre for Quantum Molecular Sciences (Hylleraas), Department of Chemistry [Oslo], Faculty of Mathematics and Natural Sciences [Oslo], University of Oslo (UiO)-University of Oslo (UiO)-Faculty of Mathematics and Natural Sciences [Oslo], and University of Oslo (UiO)-University of Oslo (UiO)
Subjects: chemistry.chemical_classification, 010405 organic chemistry, Chemistry, Alkene, Chemical shift, Alkane metathesis, General Chemistry, 010402 general chemistry, 01 natural sciences, 3. Good health, 0104 chemical sciences, Metal, Crystallography, visual_art, Chemical Sciences, visual_art.visual_art_medium, Molecule, [CHIM]Chemical Sciences, Reactivity (chemistry), Molecular orbital, Alkyl
Abstract: Chemical shift analysis predicts the ease of alkylidene formation from bis-alkyl d0 complexes via α-H abstraction., Metal alkylidenes, which are key organometallic intermediates in reactions such as olefination or alkene and alkane metathesis, are typically generated from metal dialkyl compounds [M](CH2R)2 that show distinctively deshielded chemical shifts for their α-carbons. Experimental solid-state NMR measurements combined with DFT/ZORA calculations and a chemical shift tensor analysis reveal that this remarkable deshielding originates from an empty metal d-orbital oriented in the M–Cα–Cα′ plane, interacting with the Cα p-orbital lying in the same plane. This π-type interaction inscribes some alkylidene character into Cα that favors alkylidene generation via α-H abstraction. The extent of the deshielding and the anisotropy of the alkyl chemical shift tensors distinguishes [M](CH2R)2 compounds that form alkylidenes from those that do not, relating the reactivity to molecular orbitals of the respective molecules. The α-carbon chemical shifts and tensor orientations thus predict the reactivity of metal alkyl compounds towards alkylidene generation.
Published: 2018
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29. Biporous Metal-Organic Framework with Tunable CO2/CH4 Separation Performance Facilitated by Intrinsic Flexibility

Author: Berend Smit, Jorge A. R. Navarro, Daniele Ongari, Peter G. Boyd, Iurii Dovgaliuk, Kathryn S. Deeg, Kaili Y. Ordiz, Arunraj Chidambaram, Seyed Mohamad Moosavi, Kyriakos C. Stylianou, Andrzej Gładysiak, Institut des Sciences et Ingénierie Chimiques (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, European Synchrotron Radiation Facility (ESRF), Department of Chemical and Biomolecular Engineering [Los Angeles], University of California [Los Angeles] (UCLA), Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, and Universidad de Granada (UGR)
Subjects: CO2/CH4separation, Materials science, force-field, water, breakthrough curves, gas adsorption, 010402 general chemistry, metal-oranic frameworks, 01 natural sciences, carbon-dioxide capture, crystal, Adsorption, Engineering, hydrophobic channels, Molecule, co2/ch4 separation, General Materials Science, gases, Nanoscience & Nanotechnology, [PHYS]Physics [physics], Molecular interactions, ch4, 010405 organic chemistry, biporous MOFs, 0104 chemical sciences, co2 capture, Chemical engineering, adsorption, CO2/CH4 separation, Chemical Sciences, Metal-organic framework, metal−organic frameworks, simulations, Selectivity
Abstract: International audience; In this work, we report the synthesis of SION-8, a novel metal-organic framework (MOF) based on Ca(II) and a tetracarboxylate ligand TBAPy(4-) endowed with two chemically distinct types of pores characterized by their hydrophobic and hydrophilic properties. By altering the activation conditions, we gained access to two bulk materials: the fully activated SION-8F and the partially activated SION-8P with exclusively the hydrophobic pores activated. SION-8P shows high affinity for both CO2 (Q(st) = 28.4 kJ/mol) and CH4 (Q(st) = 21.4 kJ/mol), while upon full activation, the difference in affinity for CO2 (Q(st) = 23.4 kJ/mol) and CH4 (Q(st) = 16.0 kJ/mol) is more pronounced. The intrinsic flexibility of both materials results in complex adsorption behavior and greater adsorption of gas molecules than if the materials were rigid. Their CO2/CH4 separation performance was tested in fixed-bed breakthrough experiments using binary gas mixtures of different compositions and rationalized in terms of molecular interactions. SION-8F showed a 40-160% increase (depending on the temperature and the gas mixture composition probed) of the CO2/CH4 dynamic breakthrough selectivity compared to SION-8P, demonstrating the possibility to rationally tune the separation performance of a single MOF by manipulating the stepwise activation made possible by the MOF's biporous nature.
Published: 2018
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30. n-Heptane cool flame chemistry: Unraveling intermediate species measured in a stirred reactor and motored engine

Author: Salim Sioud, Tao Tao, Misjudeen Raji, Nils Hansen, Zhandong Wang, Lena Ruwe, Katharina Kohse-Höinghaus, Bingjie Chen, David Vuilleumier, Denisia M. Popolan-Vaida, Vijai Shankar Bhavani Shankar, Philippe Dagaut, S. Mani Sarathy, Eike Bräuer, Kai Moshammer, National Synchrotron Radiation Laboratory (NSRL), University of Science and Technology of China [Hefei] (USTC), Clean Combustion Research Center - CCRC (Thuwal, Saudi Arabia), King Abdullah University of Science and Technology (KAUST), Physikalisch-Technische Bundesanstalt [Braunschweig] (PTB), Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, Universität Bielefeld, Institut de Combustion, Aérothermique, Réactivité et Environnement (ICARE), and Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut des Sciences de l'Ingénierie et des Systèmes (INSIS)
Subjects: General Chemical Engineering, Analytical chemistry, General Physics and Astronomy, Energy Engineering and Power Technology, Atmospheric-pressure chemical ionization, Photoionization, 010402 general chemistry, Mass spectrometry, 7. Clean energy, 01 natural sciences, Aldehyde, chemistry.chemical_compound, peroxides, 0103 physical sciences, synchrotron, Partial oxidation, heptane, ComputingMilieux_MISCELLANEOUS, chemistry.chemical_classification, Engine emissions, Heptane, 010304 chemical physics, Autoxidation, [SPI.FLUID]Engineering Sciences [physics]/Reactive fluid environment, oxidation mechanism, General Chemistry, Cool flame, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Fuel Technology, chemistry, 13. Climate action, jet-stirred reactor, kinetics
Abstract: This work identifies classes of cool flame intermediates from n-heptane low-temperature oxidation in a jet-stirred reactor (JSR) and a motored cooperative fuel research (CFR) engine. The sampled species from the JSR oxidation of a mixture of n-heptane/O2/Ar (0.01/0.11/0.88) were analyzed using a synchrotron vacuum ultraviolet radiation photoionization (SVUV-PI) time-of-flight molecular-beam mass spectrometer (MBMS) and an atmospheric pressure chemical ionization (APCI) Orbitrap mass spectrometer (OTMS). The OTMS was also used to analyze the sampled species from a CFR engine exhaust. Approximately 70 intermediates were detected by the SVUV-PI-MBMS, and their assigned molecular formulae are in good agreement with those detected by the APCI-OTMS, which has ultra-high mass resolving power and provides an accurate elemental C/H/O composition of the intermediate species. Furthermore, the results show that the species formed during the partial oxidation of n-heptane in the CFR engine are very similar to those produced in an ideal reactor, i.e., a JSR. The products can be classified by species with molecular formulae of C7H14Ox (x = 0–5), C7H12Ox (x = 0–4), C7H10Ox (x = 0–4), CnH2n (n = 2–6), CnH2n−2 (n = 4–6), CnH2n+2O (n = 1–4), CnH2nO (n = 1–6), CnH2n−2O (n = 2–6), CnH2n−4O (n = 4–6), CnH2n+2O2 (n = 0–4, 7), CnH2nO2 (n = 1–6), CnH2n−2O2 (n = 2–6), CnH2n−4O2 (n = 4–6), and CnH2nO3 (n = 3–6). The identified intermediate species include alkenes, dienes, aldehyde/keto compounds, olefinic aldehyde/keto compounds, diones, cyclic ethers, peroxides, acids, and alcohols/ethers. Reaction pathways forming these intermediates are proposed and discussed herein. These experimental results are important in the development of more accurate kinetic models for n-heptane and longer-chain alkanes.
Published: 2018
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31. Hydration of the sulfate dianion in size-selected water clusters: From SO42−(H2O)9 to SO42−(H2O)13

Author: Evan R. Williams, Richard J. Cooper, Carine Clavaguéra, Ayah A. Hassan, Gilles Ohanessian, Florian Thaunay, Laboratoire de chimie moléculaire (LCM), École polytechnique (X)-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: 010304 chemical physics, Hydrogen bond, Chemistry, Solvation, Analytical chemistry, Infrared spectroscopy, 010402 general chemistry, Condensed Matter Physics, 01 natural sciences, Spectral line, 0104 chemical sciences, 0103 physical sciences, Molecule, Water cluster, Physical and Theoretical Chemistry, Water binding, [CHIM.OTHE]Chemical Sciences/Other, Instrumentation, Spectroscopy, Ion cyclotron resonance
Abstract: International audience; In celebration of Jose Riveros' many essential contributions to gas phase ion chemistry. Keywords: Hydrated sulfate IRPD spectroscopy AMOEBA polarizable force field Second hydration shell Mixed quantum classical modelling O H stretching frequency a b s t r a c t Infrared photodissociation (IRPD) spectra of SO 4 2− (H 2 O) n , n = 9-13, recorded in the cooled cell of a Fourier-transform ion cyclotron resonance mass spectrometer, between 2900 and 3800 cm −1 , are reported. The structures, energetics and infrared spectra of n = 9 and 11-13 were investigated by a combination of classical polarizable molecular dynamics and static quantum chemical calculations. Low-energy structures are mainly determined by the strong structuring effect of the sulfate ion, however, the highest cohesion is achieved when strong water-water interactions are present as well. As a result, the sulfate ion in the most stable structures for n = 9, 11 and 12 is on the surface of the water cluster. While SO 4 2− (H 2 O) 9 involves a mixture of isomers, the other sizes are found to be described by a single structural family, with the most stable structures of SO 4 2− (H 2 O) 11 and SO 4 2− (H 2 O) 13 deriving from that of SO 4 2− (H 2 O) 12 by removal and addition of a water molecule, respectively, without substantial reorganization. An important feature of these structures is that the number of water molecules in the second solvation sphere increases with cluster size, up to 3 for n = 12 and 4 for n = 13. This is directly reflected in the IRPD spectra. All spectra display two main features in the 3150-3350 and 3350-3650 cm −1 range, plus a small band near 3100 cm −1. The 3350-3650 cm −1 massif, which includes most bands arising from second sphere molecules, acquires larger intensity relative to that at 3150-3350 cm −1 which is mainly composed of stretches in first sphere molecules. Whereas most water molecules have ADD coordination (where A stands for acceptor and D stands for donor of a hydrogen bond), special cases, including DD and AADD account for bands at the red and blue ends of the spectra. Computed IR spectra are able to account for most experimental features, especially when anharmonicities are taken into account for the largest red shifts. Finally, the higher abundance of n = 12 relative to other sizes is related to a lower water evaporation rate constant, in good agreement with the water binding energy which is computed to be larger for n = 12 than for 13.
Published: 2017
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32. Redox-Initiated Reactivity of Dinuclear β-Diketiminatoniobium Imido Complexes

Author: Kriegel, Benjamin, Naested, Lara, Nocton, Grégory, Lakshmi, K., Lohrey, Trevor, Bergman, Robert, Arnold, John, Laboratoire de chimie moléculaire (LCM), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Department of Chemistry [Berkeley], University of California [Berkeley], and University of California-University of California
Subjects: [CHIM.INOR]Chemical Sciences/Inorganic chemistry, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2017

33. An experimental and DFT Computational Study of β-Me and β-H elimination coupled with proton transfer; from amides to enamides in Cp*2MX, M = La and Ce

Author: Odile Eisenstein, Richard A. Andersen, Sergio S. Rozenel, Lionel Perrin, 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: Proton, 010405 organic chemistry, Chemistry, Hydride, Stereochemistry, [CHIM.ORGA]Chemical Sciences/Organic chemistry, Organic Chemistry, 010402 general chemistry, 01 natural sciences, Medicinal chemistry, 0104 chemical sciences, Ion, Inorganic Chemistry, chemistry.chemical_compound, Physical and Theoretical Chemistry, [SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM], Metallocene
Abstract: International audience; The thermal rearrangement of the f-block metallocene amides Cp*2MNR1R2, where R1 is CHMe2, R2 is either CHMe2 or CMe3, and M is either La or Ce, to the corresponding enamides Cp*2MNR1[C(Me)═CH2] and H2 or CH4, respectively, occurs when the solid amides are heated in sealed evacuated ampules at 160–180 °C for 1–2 weeks. The net reaction is a β-H or β-Me elimination followed by a γ-abstraction of a proton at the group from which the β-elimination occurs. When R1 is either SiMe3 or SiMe2CMe3 and R2 is CMe3, the enamide Cp*2MNR1[C(Me)═CH2] is isolated, the result of β-Me elimination, but when R2 is CHMe2, the enamides Cp*2MNR1[C(Me)═CH2] and Cp*2NR1[C(H)═CH2] are isolated, the result of β-H and β-Me elimination. In the latter cases, both enamides are formed in similar amounts and the rates of the β-H and β-Me elimination steps must be similar. A two-step mechanism is developed from DFT calculations. The first step is migration of a hydride or a methyl anion to the Cp*2M fragment, forming M–H or M–Me bonds as the N═C bond in the intermediate imine forms. The enamide evolves from the metal-coordinated imine by abstraction of a proton from the γ-carbon of the intermediate imine. The two elementary steps involve significant geometrical changes within the NαCβCγ set of atoms during the two-step elimination process that are in large part responsible for the relatively high activation barriers for the net reaction, which may be classified as a proton-coupled hydride or methyl anion transfer reaction.
Published: 2017
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34. Quantifying similarity of pore-geometry in nanoporous materials

Author: Kathryn Hess, Berend Smit, Pawel Dlotko, Senja Barthel, S. Mohamad Moosavi, Yong Jin Lee, Ecole Polytechnique Fédérale de Lausanne (EPFL), Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, Understanding the Shape of Data (DATASHAPE), Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Inria Saclay - Ile de France, Institut National de Recherche en Informatique et en Automatique (Inria), European Project: 339025,EC:FP7:ERC,ERC-2013-ADG,GUDHI(2014), University of California [Berkeley] (UC Berkeley), and University of California (UC)-University of California (UC)
Subjects: Multidisciplinary, Persistent homology, Similarity (geometry), Materials science, Nanoporous, Science, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Structure (category theory), General Physics and Astronomy, Geometry, [CHIM.MATE]Chemical Sciences/Material chemistry, 02 engineering and technology, General Chemistry, Orders of magnitude (numbers), 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, GeneralLiterature_MISCELLANEOUS, Article, General Biochemistry, Genetics and Molecular Biology, 0104 chemical sciences, Topological data analysis, 0210 nano-technology, A determinant
Abstract: In most applications of nanoporous materials the pore structure is as important as the chemical composition as a determinant of performance. For example, one can alter performance in applications like carbon capture or methane storage by orders of magnitude by only modifying the pore structure. For these applications it is therefore important to identify the optimal pore geometry and use this information to find similar materials. However, the mathematical language and tools to identify materials with similar pore structures, but different composition, has been lacking. We develop a pore recognition approach to quantify similarity of pore structures and classify them using topological data analysis. This allows us to identify materials with similar pore geometries, and to screen for materials that are similar to given top-performing structures. Using methane storage as a case study, we also show that materials can be divided into topologically distinct classes requiring different optimization strategies., Pore structure plays an important role in dictating gas storage performance for nanoporous materials. Here, Smit and colleagues develop a topological approach to quantify pore structure similarity, and exploit the resulting descriptor to screen for materials that possess structural similarities with top-performers.
Published: 2017
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35. 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

36. A New Supporting Ligand in Actinide Chemistry Leads to Reactive Bis(NHC)borate-Supported Thorium Complexes

Author: John Arnold, Laurent Maron, Stephan Hohloch, Mary E. Garner, 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: Actinide chemistry, 010405 organic chemistry, Ligand, Organic Chemistry, Thorium, chemistry.chemical_element, 010402 general chemistry, Photochemistry, 01 natural sciences, Medicinal chemistry, 0104 chemical sciences, Inorganic Chemistry, chemistry.chemical_compound, chemistry, [CHIM]Chemical Sciences, Chelation, Reactivity (chemistry), Singlet state, Physical and Theoretical Chemistry, Carbene, Derivative (chemistry)
Abstract: International audience; A versatile, monoanionic, chelating (bis)carbene ligand (2) was used to prepare a thorium dihalide complex (3) and a direduced-bpy derivative (4). CASSCF calculations suggest the involvement of a multiconfigurational open-shell singlet, with the main configuration corresponding to a Th(III)-bpy(−1) (f1π*1) electronic structure. The reactivity of 4 was explored in various transformations, including reactions with carbonyls and organic azides; the latter gave rise to an unusual terminal Th-imido bpy complex (6).
Published: 2016

37. On the non-innocence of 'Nacnacs': ligand-based reactivity in β-diketiminate supported coordination compounds

Author: John Arnold, Clément Camp, Laboratoire de Chimie, Catalyse, Polymères et Procédés, R 5265 (C2P2), Centre National de la Recherche Scientifique (CNRS)-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC), Department of Chemistry [Berkeley], University of California [Berkeley], and University of California-University of California
Subjects: chemistry.chemical_classification, 010405 organic chemistry, Stereochemistry, Ligand, Coordination number, Metal ions in aqueous solution, 010402 general chemistry, 01 natural sciences, Combinatorial chemistry, Redox, 3. Good health, 0104 chemical sciences, Coordination complex, Inorganic Chemistry, β diketiminate, chemistry, [CHIM]Chemical Sciences, Reactivity (chemistry), ComputingMilieux_MISCELLANEOUS
Abstract: While β-diketiminate (BDI or ‘nacnac’) ligands have been widely adopted to stabilize a wide range of metal ions in multiple oxidation states and coordination numbers, in several occurrences these ligands do not behave as spectators and participate in reactivity. Besides unwanted decomposition processes, BDI redox non-innnocence and unusual metal–ligand cooperative activation of substrates yielding attractive reactivity have been reported. This feature article will provide a comprehensive analysis of the various transformations involving BDI ligand platforms in coordination compounds across the periodic table.
Published: 2016

38. Photo-activation of d 0 niobium imido azides: en route to nitrido complexes

Author: Clément CAMP, Grant, Lauren N., Bergman, Robert G., John Arnold, Laboratoire de Chimie, Catalyse, Polymères et Procédés, R 5265 (C2P2), Centre National de la Recherche Scientifique (CNRS)-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC), Department of Chemistry [Berkeley], University of California [Berkeley], and University of California-University of California
Subjects: [CHIM]Chemical Sciences, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2016

39. MCTDHB physics and technologies: Excitations and vorticity, single-shot detection, measurement of fragmentation, and optimal control in correlated ultra-cold bosonic many-body Systems

Author: Tommaso Calarco, Antonio Negretti, Raphael Beinke, Alexej I. Streltsov, Lorenz S. Cederbaum, Oksana I. Streltsova, Kaspar Sakmann, Vanderlei Salvador Bagnato, Ioannis Brouzos, Tommaso Caneva, Simone Montangero, Tomos Wells, Ressa S. Said, Marcus Theisen, Shachar Klaiman, Ofir E. Alon, Storm E. Weiner, Mark A. Kasevich, Marios C. Tsatsos, Axel U. J. Lode, Department of Mathematics-Physics [Haifa at Oranim], University of Haifa [Haifa], Institute of Physics [São Paulo], University of São Paulo (USP), Theoretische Chemie Universität Heidelberg, Universität Heidelberg [Heidelberg], Universität Ulm - Ulm University [Ulm, Allemagne], Institute for Complex Quantum Systems (ICQ), Institut de Ciencies Fotoniques [Castelldefels] (ICFO), Department of Physics [Basel], University of Basel (Unibas), Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, Department of Mathematics [Cambridge] (HARVARD), and Harvard University [Cambridge]
Subjects: Physics, [PHYS]Physics [physics], Computer Science (all), Physics and Astronomy (all), Mathematics (all), Chemistry (all), Quantum dynamics, Hartree, Vorticity, Optimal control, 01 natural sciences, 010305 fluids & plasmas, Vortex, Classical mechanics, MCTDH, 0103 physical sciences, [CHIM]Chemical Sciences, Statistical physics, 010306 general physics, Quantum, ComputingMilieux_MISCELLANEOUS, Boson, Coherence (physics)
Abstract: Here we report on further applications, developments, expansion, and proliferation of the Multi-Configurational Time-Dependent Hartree for Bosons (MCTDHB) method in the context of ultra-cold atomic systems. In this year we put our main efforts to understanding and generalizing vortices—two-dimensional (2D) and three-dimensional (3D) quantum objects carrying angular momentum—from the perspective of the many-body physics. We have studied static properties and quantum dynamics of vortices confined in simple parabolic traps and in circular traps. Particular emphasis has been put on the loss of coherence and build-up of the fragmentation. Complimentary, we continue to develop the MCTDHB method spanning several directions of the theoretical and computational physics as well as optimal-control theory: (a) the linear-response on-top of the MCTDHB method (LR-MCTDHB) has been reformulated in a compact block form, expanded for general inter-particle interactions, and benchmarked against the exactly-solvable harmonic-interaction model; (b) a new analysis tool capable of simulating the outcomes of typical shots generated in the experimental detection of ultra-cold atomic systems has been invented, tested, and applied; (c) a novel algorithm offering a direct quantitative measurement of the possible fragmentation in bosonic systems has been proposed and applied; (d) the optimal-control Chopped RAndom Basis (CRAB) algorithm has been merged with the MCTDHB package and applied to manipulate quantum systems. Implications and further perspectives and future research plans are briefly discussed and addressed.
Published: 2016
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40. 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
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41. 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
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42. 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
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43. Stochastic dynamics of collective modes for Brownian dipoles

Author: Frédéric van Wijland, Leticia F. Cugliandolo, Pierre-Michel Déjardin, Gustavo S. Lozano, Laboratoire de Physique Théorique et Hautes Energies (LPTHE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), LAboratoire de Mathématiques et PhySique (LAMPS), Université de Perpignan Via Domitia (UPVD), Departamento de Física [Buenos Aires], Facultad de Ciencias Exactas y Naturales [Buenos Aires] (FCEyN), Universidad de Buenos Aires [Buenos Aires] (UBA)-Universidad de Buenos Aires [Buenos Aires] (UBA), Matière et Systèmes Complexes (MSC (UMR_7057)), Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, LAboratoire de Modélisation Pluridisciplinaire et Simulations (LAMPS), Matière et Systèmes Complexes (MSC), University of California [Berkeley] (UC Berkeley), and University of California (UC)-University of California (UC)
Subjects: Ciencias Físicas, FOS: Physical sciences, Dipoles, Condensed Matter - Soft Condensed Matter, Space (mathematics), 7. Clean energy, purl.org/becyt/ford/1 [https], Stochastic differential equation, Statistical physics, Colloids, Condensed Matter - Statistical Mechanics, Brownian motion, Physics, [PHYS]Physics [physics], Statistical Mechanics (cond-mat.stat-mech), Brownian, purl.org/becyt/ford/1.3 [https], Langevin equation, Astronomía, Classical mechanics, Brownian dynamics, Soft Condensed Matter (cond-mat.soft), Density functional theory, Brillouin and Langevin functions, Rotation (mathematics), CIENCIAS NATURALES Y EXACTAS
Abstract: The individual motion of a colloidal particle is described by an overdamped Langevin equation. When rotational degrees of freedom are relevant, these are described by a corresponding Langevin process. Our purpose is to show that the microscopic local density of colloids, in terms of a space and rotation state, also evolves according to a Langevin equation. The latter can then be used as the starting point of a variety of approaches, ranging from dynamical density functional theory to mode-coupling approximations. Fil: Cugliandolo, Leticia Fernanda. Universite Pierre et Marie Curie; Francia Fil: Déjardin, Pierre Michel. Université de Perpignan Via Domitia; Francia Fil: Lozano, Gustavo Sergio. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Van Wijland, Frédéric. Université Paris Diderot - Paris 7; Francia. University of California at Berkeley; Estados Unidos
Published: 2015
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44. Roadmap on optical energy conversion

Author: Krzysztof Kempa, Shanhui Fan, Carmel Rotschild, Kylie R. Catchpole, Volker J. Sorger, Andriy Zakutayev, Michael D. Wisser, Ivan Celanovic, Eli Yablonovitch, Peter Bermel, Alberto Salleo, Stephan Lany, Ralph G. Nuzzo, Noah D. Bronstein, Jean-Jacques Greffet, Mario Dagenais, Lu Xu, Jennifer A. Dionne, A. Paul Alivisatos, Di Wu, Yuan Yao, Xing Sheng, Martin A. Green, Gang Chen, Linxiao Zhu, Marin Soljacic, Talia S. Gershon, Assaf Manor, Svetlana V. Boriskina, Aaswath Raman, John A. Rogers, Jeffrey M. Gordon, Yoshitaka Okada, Michael J. Naughton, Matthew C. Beard, Mohammad H. Tahersima, Department of Mechanical Engineering [Massachusetts Institute of Technology] (MIT-MECHE), Massachusetts Institute of Technology (MIT), University of New South Wales [Sydney] (UNSW), Department of Electrical Engineering and Computer Science [Berkeley] (EECS), University of California [Berkeley], University of California-University of California, Research School of Physics and Engineering [Canberra} (RSPE), Australian National University (ANU), Materials Science Division [LBNL Berkeley], Lawrence Berkeley National Laboratory [Berkeley] (LBNL), National Renewable Energy Laboratory, Golden, Research Center for Advanced Science and Technology [Tokyo] (RCAST), The University of Tokyo (UTokyo), IBM T. J. Watson Research Centre, Department of Electrical and Computer Engineering [George Washington University] (ECE), The George Washington University (GW), Department of Physics [UMass, Boston], University of Massachusetts [Boston] (UMass Boston), University of Massachusetts System (UMASS)-University of Massachusetts System (UMASS), Department of Electrical and Computer Engineering [Univ. of Maryland] (ECE - University of Maryland), University of Illinois at Urbana-Champaign [Urbana], University of Illinois System, Department of Chemistry [Berkeley], Department of Solar Energy and Environmental Physics, Department of Materials Science and Engineering [Stanford], Stanford University, Purdue University [West Lafayette], Laboratoire Charles Fabry / Naphel, Laboratoire Charles Fabry (LCF), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut d'Optique Graduate School (IOGS)-Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut d'Optique Graduate School (IOGS), Russell Berrie Nanotechnology Institute, Technion, Israel Institute of Technology, Technion - Israel Institute of Technology [Haifa], and Department of Electrical Engineering [Stanford]
Subjects: Nanophotonics, Physics::Optics, Optical Physics, 02 engineering and technology, Photon energy, 01 natural sciences, Optics, light harvesting, Photovoltaics, Waste heat, 0103 physical sciences, Energy transformation, solar technology, Electrical and Electronic Engineering, 010302 applied physics, Quantum Physics, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], business.industry, 021001 nanoscience & nanotechnology, Solar energy, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, Renewable energy, solar cell, photovoltaics, 0210 nano-technology, business, Energy source, optical energy conversion
Abstract: © 2016 IOP Publishing Ltd. For decades, progress in the field of optical (including solar) energy conversion was dominated by advances in the conventional concentrating optics and materials design. In recent years, however, conceptual and technological breakthroughs in the fields of nanophotonics and plasmonics combined with a better understanding of the thermodynamics of the photon energy-conversion processes reshaped the landscape of energy-conversion schemes and devices. Nanostructured devices and materials that make use of size quantization effects to manipulate photon density of states offer a way to overcome the conventional light absorption limits. Novel optical spectrum splitting and photon-recycling schemes reduce the entropy production in the optical energy-conversion platforms and boost their efficiencies. Optical design concepts are rapidly expanding into the infrared energy band, offering new approaches to harvest waste heat, to reduce the thermal emission losses, and to achieve noncontact radiative cooling of solar cells as well as of optical and electronic circuitries. Light-matter interaction enabled by nanophotonics and plasmonics underlie the performance of the third- and fourth-generation energy-conversion devices, including up- and down-conversion of photon energy, near-field radiative energy transfer, and hot electron generation and harvesting. Finally, the increased market penetration of alternative solar energy-conversion technologies amplifies the role of cost-driven and environmental considerations. This roadmap on optical energy conversion provides a snapshot of the state of the art in optical energy conversion, remaining challenges, and most promising approaches to address these challenges. Leading experts authored 19 focused short sections of the roadmap where they share their vision on a specific aspect of this burgeoning research field. The roadmap opens up with a tutorial section, which introduces major concepts and terminology. It is our hope that the roadmap will serve as an important resource for the scientific community, new generations of researchers, funding agencies, industry experts, and investors.
Published: 2016
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45. The Arabidopsis COBRA protein facilitates cellulose crystallization at the plasma membrane

Author: David E. Wemmer, Heidi Szemenyei, Hagit Sorek, Kian Hématy, Nadav Sorek, Aleksandra Kijac, Chris Somerville, Stephan Bauer, Plant and Microbial Biology Department, Energy Biosciences Institute, Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, Plant and Microbial Biology, Institut Jean-Pierre Bourgin (IJPB), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, and Department of Chemistry
Subjects: 0106 biological sciences, [SDV]Life Sciences [q-bio], Arabidopsis, Plant Biology, Cobra, 01 natural sciences, Biochemistry, law.invention, chemistry.chemical_compound, fluids and secretions, Cell Wall, law, plant cell wall, Arabidopsis COBRA, Crystallization, isothermal titration calorimetry (ITC), Glucans, computer.programming_language, chemistry.chemical_classification, 0303 health sciences, Membrane Glycoproteins, respiratory system, Molecular Imaging, Protein Transport, Membrane, Additions and Corrections, chemical and pharmacologic phenomena, Biology, Polysaccharide, Fibril, complex mixtures, Cell wall, 03 medical and health sciences, Cellulose synthase complex, Cellulose, Molecular Biology, Glucan, 030304 developmental biology, solid state NMR, Arabidopsis Proteins, Cell Membrane, Isothermal titration calorimetry, Cell Biology, Plasma, cellulose, cellulose biosynthesis, plant biochemistry, chemistry, Chemical engineering, computer, 010606 plant biology & botany
Abstract: Mutations in the Arabidopsis COBRA gene lead to defects in cellulose synthesis but the function of COBRA is unknown. Here we present evidence that COBRA localizes to discreet particles in the plasma membrane and is sensitive to inhibitors of cellulose synthesis, suggesting that COBRA and the cellulose synthase complex reside in very close proximity on the plasma membrane. Live-cell imaging of cellulose synthesis indicated that, once initiated, cellulose synthesis appeared to proceed normally in the cobra mutant. Using isothermal calorimetry, COBRA was found to bind individual beta-1,4-linked glucan chains with a KA of 3.2muM. Competition assays suggests that COBRA binds individual beta-1,4-linked glucan chains with higher affinity than crystalline cellulose. Solid-state nuclear magnetic resonance (SSNMR) studies of the cell wall of the cobra mutant also indicated that, in addition to decreases in cellulose amount, the properties of the cellulose fibrils and other cell wall polymers differed from wild type by being less crystalline and having an increased number of reducing ends. We interpret the available evidence as suggesting that COBRA facilitates cellulose crystallization from the emerging beta-1,4 glucan chains by acting as a ''polysaccharide chaperone''.
Published: 2015
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46. 17 O NMR Spectroscopy Reveals CO 2 Speciation and Dynamics in Hydroxide-Based Carbon Capture Materials.

Author: Rhodes BJ, Schaaf LL, Zick ME, Pugh SM, Hilliard JS, Sharma S, Wade CR, Milner PJ, Csányi G, and Forse AC
Abstract: Carbon dioxide capture technologies are set to play a vital role in mitigating the current climate crisis. Solid-state 17 O NMR spectroscopy can provide key mechanistic insights that are crucial to effective sorbent development. In this work, we present the fundamental aspects and complexities for the study of hydroxide-based CO 2 capture systems by 17 O NMR. We perform static density functional theory (DFT) NMR calculations to assign peaks for general hydroxide CO 2 capture products, finding that 17 O NMR can readily distinguish bicarbonate, carbonate and water species. However, in application to CO 2 binding in two test case hydroxide-functionalised metal-organic frameworks (MOFs) - MFU-4l and KHCO 3 -cyclodextrin-MOF, we find that a dynamic treatment is necessary to obtain agreement between computational and experimental spectra. We therefore introduce a workflow that leverages machine-learning force fields to capture dynamics across multiple chemical exchange regimes, providing a significant improvement on static DFT predictions. In MFU-4l, we parameterise a two-component dynamic motion of the bicarbonate motif involving a rapid carbonyl seesaw motion and intermediate hydroxyl proton hopping. For KHCO 3 -CD-MOF, we combined experimental and modelling approaches to propose a new mixed carbonate-bicarbonate binding mechanism and thus, we open new avenues for the study and modelling of hydroxide-based CO 2 capture materials by 17 O NMR., (© 2024 The Authors. ChemPhysChem published by Wiley-VCH GmbH.)
Published: 2025
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47. Photochemical pathways in astronomical ices: A computational study of singlet oxygen reactions with hydrocarbons.

Author: Daniely A, Zamir A, Eisenberg HR, Livshits E, Piacentino E, Bergner JB, Öberg KI, and Stein T
Abstract: Complex organic molecules are widespread in different areas of the interstellar medium, including cold areas, such as molecular clouds, where chemical reactions occur in ice. Among the observed molecules are oxygen-bearing organic molecules, which are of high interest given their significant role in astrobiology. Despite the observed rich chemistry, the underlying molecular mechanisms responsible for molecular formation in such cold dilute areas are still not fully understood. In this paper, we study the unique chemistry taking place in astronomically relevant ices, where UV radiation is a central driving force for chemical reactions. Photofragmentation of ice components gives rise to highly reactive species, such as the O(1D) atom. These species provide a pathway for chemical complexity even in cold areas. Using quantum chemistry calculations, we demonstrate that O(1D) reacts barrierlessly with hydrocarbons. Moreover, photoprocessing of the reaction products (and other components of the ice), followed by radical recombination, is found to be an essential part of the overall mechanism. In ice containing O(1D) and hydrocarbons, the formation of formaldehyde in methane ice, acetaldehyde in ethane ice, and carbon monoxide in acetylene ice, and the consumption of alcohol in all systems, was predicted in agreement with experimental results., (© 2025 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International (CC BY-NC-ND) license (https://creativecommons.org/licenses/by-nc-nd/4.0/).)
Published: 2025
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48. Coexistence of Interacting Charge Density Waves in a Layered Semiconductor.

Author: Lv BQ, Zong A, Wu D, Nie Z, Su Y, Choi D, Ilyas B, Fichera BT, Li J, Baldini E, Mogi M, Huang YB, Po HC, Meng S, Wang Y, Wang NL, and Gedik N
Abstract: Coexisting orders are key features of strongly correlated materials and underlie many intriguing phenomena from unconventional superconductivity to topological orders. Here, we report the coexistence of two interacting charge-density-wave (CDW) orders in EuTe_{4}, a layered crystal that has drawn considerable attention owing to its anomalous thermal hysteresis and a semiconducting CDW state despite the absence of perfect Fermi surface nesting. By accessing unoccupied conduction bands with time- and angle-resolved photoemission measurements, we find that monolayers and bilayers of Te in the unit cell host different CDWs that are associated with distinct energy gaps. The two gaps display dichotomous evolutions following photoexcitation, where the larger bilayer CDW gap exhibits less renormalization and faster recovery. Surprisingly, the CDW in the Te monolayer displays an additional momentum-dependent gap renormalization that cannot be captured by density-functional theory calculations. This phenomenon is attributed to interlayer interactions between the two CDW orders, which account for the semiconducting nature of the equilibrium state. Our findings not only offer microscopic insights into the correlated ground state of EuTe_{4} but also provide a general nonequilibrium approach to understand coexisting, layer-dependent orders in a complex system.
Published: 2024
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49. The role of charge in microdroplet redox chemistry.

Author: Heindel JP, LaCour RA, and Head-Gordon T
Abstract: In charged water microdroplets, which occur in nature or in the lab upon ultrasonication or in electrospray processes, the thermodynamics for reactive chemistry can be dramatically altered relative to the bulk phase. Here, we provide a theoretical basis for the observation of accelerated chemistry by simulating water droplets of increasing charge imbalance to create redox agents such as hydroxyl and hydrogen radicals and solvated electrons. We compute the hydration enthalpy of OH - and H + that controls the electron transfer process, and the corresponding changes in vertical ionization energy and vertical electron affinity of the ions, to create OH • and H • reactive species. We find that at ~ 20 - 50% of the Rayleigh limit of droplet charge the hydration enthalpy of both OH - and H + have decreased by >50 kcal/mol such that electron transfer becomes thermodynamically favorable, in correspondence with the more favorable vertical electron affinity of H + and the lowered vertical ionization energy of OH - . We provide scaling arguments that show that the nanoscale calculations and conclusions extend to the experimental microdroplet length scale. The relevance of the droplet charge for chemical reactivity is illustrated for the formation of H 2 O 2 , and has clear implications for other redox reactions observed to occur with enhanced rates in microdroplets., (© 2024. The Author(s).)
Published: 2024
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50. Delamination-Assisted Ultrafast Wrinkle Formation in a Freestanding Film.

Author: Su Y, Zong A, Kogar A, Lu D, Hong SS, Freelon B, Rohwer T, Wang BY, Hwang HY, and Gedik N
Abstract: Freestanding films provide a versatile platform for materials engineering thanks to additional structural motifs not found in films with a substrate. A ubiquitous example is wrinkles, yet little is known about how they can develop over as fast as a few picoseconds due to a lack of experimental probes to visualize their dynamics in real time on the nanoscopic scale. Here, we use time-resolved electron diffraction to directly observe light-activated wrinkling formation in freestanding La 2/3 Ca 1/3 MnO 3 films. Via a "lock-in" analysis of oscillations in the diffraction peak position, intensity, and width, we quantitatively reconstructed how wrinkles develop on the time scale of lattice vibration. Contrary to the common assumption of fixed boundary conditions, we found that wrinkle development is associated with ultrafast delamination at the film boundaries. Our work provides a generic protocol to quantify wrinkling dynamics in freestanding films and highlights the importance of the film-substrate interaction in determining the properties of freestanding structures.
Published: 2023
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