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251. Aqueous Solvation of SmI

Author: Alejandro, Ramirez-Solis, Jorge Iván, Amaro-Estrada, Jorge, Hernández-Cobos, and Laurent, Maron
Abstract: We report the results of Born-Oppenheimer molecular dynamics (BOMD) simulations on the aqueous solvation of the SmI
Published: 2018

252. The role of H2O in the electron transfer-activation of substrates using SmI2: insights from DFT

Author: Lionel Perrin, Laurent Maron, David J. Procter, and Xuefei Zhao
Subjects: chemistry.chemical_classification, Ketone, 010405 organic chemistry, Radical, Substrate (chemistry), Context (language use), 010402 general chemistry, Photochemistry, 01 natural sciences, 0104 chemical sciences, Inorganic Chemistry, Electron transfer, chemistry.chemical_compound, Ketyl, chemistry, Computational chemistry, Reagent, Molecule
Abstract: The first detailed theoretical study on the synthetically important electron transfer (ET) reductant SmI2-H2O has been conducted in the context of the activation of important alkyliodide, ketone, lactone and ester substrates, processes of importance in cross-coupling. Our studies give major insights into the nature of the reagent and suggest that; (i) H2O has a high affinity for Sm(ii) and displaces iodine from the metal center; (ii) SmI2-H2O has 6-7 molecules of H2O directly bound to the metal center; (iii) binding of H2O to Sm(II) promotes coordination of the substrate to Sm(II) and subsequent ET; (iv) resultant ketyl radicals are stabilized by hydrogen-bonding to H2O. The findings add greatly to the understanding of SmI2-H2O and the role of H2O in ET processes, and will facilitate the design of new processes initiated by reductive ET.
Published: 2016
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253. Facile CO Cleavage by a Multimetallic CsU2 Nitride Complex

Author: Marta Falcone, Marinella Mazzanti, Rosario Scopelliti, Christos E. Kefalidis, and Laurent Maron
Subjects: Valence (chemistry), 010405 organic chemistry, Chemistry, Cooperativity, Disproportionation, General Medicine, General Chemistry, Nitride, 010402 general chemistry, Photochemistry, 01 natural sciences, 7. Clean energy, Catalysis, 0104 chemical sciences, Chemical bond, Molecule, Group 2 organometallic chemistry
Abstract: Uranium nitrides are important materials with potential for application as fuels for nuclear power generation, and as highly active catalysts. Molecular nitride compounds could provide important insight into the nature of the uranium-nitride bond, but currently little is known about their reactivity. In this study, we found that a complex containing a nitride bridging two uranium centers and a cesium cation readily cleaved the C≡O bond (one of the strongest bonds in nature) under ambient conditions. The product formed has a [CsU2 (μ-CN)(μ-O)] core, thus indicating that the three cations cooperate to cleave CO. Moreover, the addition of MeOTf to the nitride complex led to an exceptional valence disproportionation of the CsU(IV) -N-U(IV) core to yield CsU(III) (OTf) and [MeN=U(V) ] fragments. The important role of multimetallic cooperativity in both reactions is illustrated by the computed reaction mechanisms.
Published: 2016
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254. Activation of SO2 by [Zn(Cp)2] and [(Cp)ZnI–ZnI(Cp*)]

Author: Carlos Alvarez Lamsfus, Neda Kazeminejad, Peter W. Roesky, Rory P. Kelly, Laurent Maron, Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), 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), Modélisation Physique et Chimique (LPCNO), 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), 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), 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), 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)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC)
Subjects: 010405 organic chemistry, Lability, Chemistry, Thermal decomposition, Metals and Alloys, General Chemistry, 010402 general chemistry, 01 natural sciences, Medicinal chemistry, Catalysis, 3. Good health, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Materials Chemistry, Ceramics and Composites, [CHIM]Chemical Sciences, Reactivity (chemistry)
Abstract: International audience; Interesting reactivity was observed in reactions of SO2 with [Zn(Cp*)2] and [(Cp*)ZnI–ZnI(Cp*)]. These reactions proceeded with insertion of SO2 into the Zn–C bonds. Spectacularly, the lability of the C–S bond in the O2SCp* ligands led to the thermal decomposition of [Zn(O2SCp*)2(tmeda)] to afford [Zn2(μ-SO3)(μ-S2O4)(tmeda)2].
Published: 2016
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255. Facile hydrogen atom transfer to iron(<scp>iii</scp>) imido radical complexes supported by a dianionic pentadentate ligand

Author: Christos E. Kefalidis, Michael L. Neidig, Warren E. Piers, Stephanie H. Carpenter, Denis M. Spasyuk, Laurent Maron, Department of Chemistry, University of Calgary, University of Calgary, Department of Chemistry [Rochester], University of Rochester [USA], 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 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: 010405 organic chemistry, Ligand, Radical, General Chemistry, Hydrogen atom, 010402 general chemistry, Photochemistry, 01 natural sciences, 0104 chemical sciences, chemistry.chemical_compound, chemistry, Yield (chemistry), Polymer chemistry, Mössbauer spectroscopy, [CHIM]Chemical Sciences, Derivative (chemistry)
Abstract: International audience; A dianionic tetrapodal pentadentate diborate ligand is introduced. This ligand forms a high spin neutral iron(II) complex that reacts with a variety of organoazides to yield transient Fe(III) imido radicals that are extremely potent hydrogen atom abstractors. The nature of these species is supported by full characterization of the Fe(III) amido products, kinetic studies, density functional computations and Mössbauer spectroscopy on the –C6H4-p-tBu substituted derivative.
Published: 2016
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256. Mechanistic insights from theory on the reduction of CO2, N2O, and SO2 molecules using tripodal diimine-enolate substituted magnesium(<scp>i</scp>) dimers

Author: Christos E. Kefalidis, Cameron Jones, and Laurent Maron
Subjects: 010405 organic chemistry, Chemistry, Stereochemistry, Magnesium, NacNac, chemistry.chemical_element, Disproportionation, 010402 general chemistry, 01 natural sciences, Medicinal chemistry, 0104 chemical sciences, Inorganic Chemistry, Metal, chemistry.chemical_compound, visual_art, visual_art.visual_art_medium, Molecule, Reactivity (chemistry), Diimine
Abstract: The mechanistic investigation of the reductive coupling vs. reductive disproportionation of CO2 using magnesium(i) dimers bearing tripodal ligands, [{Mg[κ(3)-N,N',O-(ArNCMe)2(OCCPh2)CH]}2] (Ar = C6H3Et2-2,6) has been carried out using DFT computational methods. We also elucidated the reduction of N2O to form a μ-oxo magnesium complex which upon addition of CO2 affords the experimentally observed carbonate complex. Finally, the interesting reactivity towards SO2 is considered and some insights into the mechanistic aspects of such activation/homo-coupling reaction are given for both "Nacnac" substituted magnesium(i) dimers ([{((Dip)Nacnac)Mg}2] ((Dip)Nacnac = [(DipNCMe)2CH](-), Dip = C6H3Pr(i)2-2,6)) and those bearing tripodal ligands. The analogy between the activation chemistry of low-valent f-block metal complexes with that of magnesium systems is highlighted.
Published: 2016
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257. Synthesis and reactivity of a terminal uranium(<scp>iv</scp>) sulfide supported by siloxide ligands

Author: Karsten Meyer, Jacques Pécaut, Julie Andrez, Rosario Scopelliti, Marinella Mazzanti, Christos E. Kefalidis, Laurent Maron, Michael W. Rosenzweig, Institut des Sciences et Ingénierie Chimiques (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé (SYMMES), Institut de Chimie du CNRS (INC)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)-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), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), 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), Institute of Chemical Sciences and Engineering, SB, GGEC Station 6 (EPFL), 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), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, and Inorganic Chemistry, Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM) (ICMM)
Subjects: chemistry.chemical_classification, Sulfide, 010405 organic chemistry, Stereochemistry, Siloxide, chemistry.chemical_element, Protonation, General Chemistry, Naturwissenschaftliche Fakultät, Uranium, 010402 general chemistry, 01 natural sciences, Sulfur, 0104 chemical sciences, Chemistry, chemistry.chemical_compound, chemistry, ddc:540, [CHIM]Chemical Sciences, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Reactivity (chemistry), Lewis acids and bases, Triphenylphosphine sulfide, ComputingMilieux_MISCELLANEOUS
Abstract: The S-transfer reaction from Ph3PS to the tetrasiloxide U(iii) complex [U(OSi(OtBu)3)4K] affords a stable U(iv) triply bonded terminal sulfide that can be protonated to yield a U(iv) doubly bonded terminal hydrosulfide., The reactions of the tetrasiloxide U(iii) complexes [U(OSi(OtBu)3)4K] and [U(OSi(OtBu)3)4][K18c6] with 0.5 equiv. of triphenylphosphine sulfide led to reductive S-transfer reactions, affording the U(iv) sulfide complexes [SU(OSi(OtBu)3)4K2]2, 1, and [{SU(OSi(OtBu)3)4K2}2(μ-18c6)], 2, with concomitant formation of the U(iv) complex [U(OSi(OtBu)3)4]. Addition of 1 equiv. of 2.2.2-cryptand to complex 1 resulted in the isolation of a terminal sulfide complex, [SU(OSi(OtBu)3)4K][Kcryptand], 3. The crucial role of the K+ Lewis acid in these reductive sulfur transfer reactions was confirmed, since the formation of complex 3 from the reaction of the U(iii) complex [U(OSi(OtBu)3)4][Kcryptand] and 0.5 equiv. of PPh3S was not possible. Reactivity studies of the U(iv) sulfide complexes showed that the sulfide is easily transferred to CO2 and CS2 to afford S-functionalized products. Moreover, we have found that the sulfide provides a convenient precursor for the synthesis of the corresponding U(iv) hydrosulfide, {[(SH)U(OSi(OtBu)3)4][K18c6]}, 5, after protonation with PyHCl. Finally, DFT calculations were performed to investigate the nature of the U–S bond in complexes 1, 3 and 5. Based on various analyses, triple-bond character was suggested for the U–S bond in complexes 1 and 3, while double-bond character was determined for the U–SH bond in complex 5.
Published: 2016
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258. Formation of a Bridging Phosphinidene Thorium Complex

Author: Andrew C. Behrle, Laurent Maron, Justin R. Walensky, and Ludovic Castro
Subjects: 010405 organic chemistry, Thorium, chemistry.chemical_element, General Chemistry, 010402 general chemistry, 01 natural sciences, Biochemistry, Medicinal chemistry, Catalysis, Methane, 0104 chemical sciences, chemistry.chemical_compound, Colloid and Surface Chemistry, Deprotonation, chemistry, Phosphinidene, Phosphine, Isopropyl, Methyl group
Abstract: The synthesis and structural determination of the first thorium phosphinidene complex are reported. The reaction of 2 equiv of (C5Me5)2Th(CH3)2 with H2P(2,4,6-(i)Pr3C6H2) at 95 °C produces [(C5Me5)2Th]2(μ2-P[(2,6-CH2CHCH3)2-4-(i)PrC6H2] as well as 4 equiv of methane, 2 equiv from deprotonation of the phosphine and 2 equiv from C-H bond activation of one methyl group of each of the isopropyl groups at the 2- and 6-positions. Transition state calculations indicate that the steps in the mechanism are P-H, C-H, C-H, and then P-H bond activation to form the phosphinidene.
Published: 2015
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259. Thorium Mono- and Bis(imido) Complexes Made by Reprotonation of cyclo-Metalated Amides

Author: Nicola L. Bell, Laurent Maron, and Polly L. Arnold
Subjects: chemistry.chemical_classification, Double bond, Chemistry, Stereochemistry, Aryl, Thorium, chemistry.chemical_element, General Chemistry, Actinide, Biochemistry, Bond order, Medicinal chemistry, Catalysis, chemistry.chemical_compound, Colloid and Surface Chemistry, Hydrocarbon, Molecule
Abstract: Molecules containing actinide–nitrogen multiple bonds are of current interest as simple models for new actinide nitride nuclear fuels, and for their potential for the catalytic activation of inert hydrocarbon C–H bonds. Complexes with up to three uranium–nitrogen double bonds are now being widely studied, yet those with one thorium–nitrogen double bond are rare, and those with two are unknown. A new, simple mono(imido) thorium complex and the first bis(imido) thorium complex, K[Th(═NAr)N″3] and K2[Th(═NAr)2N″2], are readily made from insertion reactions (Ar = aryl, N″ = N(SiMe3)2) into the Th–C bond of the cyclometalated thorium amides [ThN″2(N(SiMe3)(SiMe2CH2))] and K[ThN″(N(SiMe3)(SiMe2CH2))2]. X-ray and computational structural analyses show a “transition-metal-like” cis-bis(imido) geometry and polarized Th═N bonds with twice the Wiberg bond order of the formally single Th–N bond in the same molecule.
Published: 2015
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260. Yttrium Dihydride Cation [YH2(THF)2]+n: Aggregate Formation and Reaction with (NNNN)-Type Macrocycles

Author: Waldemar Fegler, Laurent Maron, Iker del Rosal, Romuald Poteau, Mathias U. Kramer, Stefan Arndt, Thomas P. Spaniol, Jun Okuda, and Yumiko Nakajima
Subjects: Organic Chemistry, Inorganic chemistry, chemistry.chemical_element, Yttrium, Medicinal chemistry, Lutetium, Ion, Dication, Inorganic Chemistry, Solvent, chemistry.chemical_compound, chemistry, Phenylsilane, Hydrogenolysis, Benzophenone, Physical and Theoretical Chemistry
Abstract: Monocationic bis(hydrocarbyl)yttrium complexes [YR2(THF)2][A] (R = CH2SiMe3, CH2C6H4-o-NMe2; A = weakly coordinating anion) underwent hydrogenolysis using dihydrogen or phenylsilane to give a mixture of polynuclear solvent-stabilized dihydride cations [YH2(THF)2]n[A]n. The mixture composition as well as the nuclearity n depended on the starting material, solvent, and reaction conditions. NMR spectroscopic data in solution and X-ray diffraction data suggested that the main product was tetranuclear, although conclusive structural data were not obtained. DFT calculations supported a closo-type tetrahedral [YH2(THF)2]44+ core. The hydridic character of these cations was revealed by their reaction with benzophenone to give the bis(diphenylmethoxy) cation [Y(OCHPh2)2(THF)4][AlR4]. The reaction of this cluster with the (NNNN)-type macrocycle Me4TACD under dihydrogen gave the dinuclear tetrahydride dication with quadruply bridging hydride ligands, [Y2(μ-H)4(Me4TACD)2][A]2, analogous to the previously characterized lutetium derivative. NH-acidic (Me3TACD)H gave the dinuclear dihydride dication [Y2(μ-H)2(Me3TACD)2(THF)2][A]2.
Published: 2015
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261. Activation of CO by Hydrogenated Magnesium(I) Dimers: Sterically Controlled Formation of Ethenediolate and Cyclopropanetriolate Complexes

Author: Ralte Lalrempuia, Laurent Maron, Simon J. Bonyhady, Benedikt Schwarze, Andreas Stasch, Christos E. Kefalidis, Cameron Jones, School of Chemistry, Monash University, 3800 Clayton, Victoria (Australie), Monash University [Clayton], 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), School of Chemistry, Monash UniVersity, Clayton, VIC. 3800 (Australia), 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: Steric effects, 010405 organic chemistry, Chemistry, Hydride, Magnesium, Inorganic chemistry, chemistry.chemical_element, NacNac, General Chemistry, 010402 general chemistry, 01 natural sciences, Biochemistry, Medicinal chemistry, Catalysis, 0104 chemical sciences, Metal, chemistry.chemical_compound, Colloid and Surface Chemistry, visual_art, visual_art.visual_art_medium, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Co activation, Oxygenate
Abstract: International audience; This study details the formal hydrogenation of two magnesium(I) dimers {(Nacnac)Mg}2 (Nacnac = [{(C6H3R2-2,6)NCMe}2CH]−; R = Pri (DipNacnac), Et (DepNacnac)) using 1,3-cyclohexadiene. These reactions afford the magnesium(II) hydride complexes, {(Nacnac)Mg(μ-H)}2. Their reactions with excess CO are sterically controlled and lead cleanly to different C–C coupled products, viz. the ethenediolate complex, (DipNacnac)Mg{κ1-O-[(DipNacnac)Mg(κ2-O,O-O2C2H2)]}, and the first cyclopropanetriolate complex of any metal, cis-{(DepNacnac)Mg}3{μ-C3(H3)O3}. Computational studies imply the CO activation processes proceed via very similar mechanisms to those previously reported for related reactions involving f-block metal hydride compounds. This work highlights the potential magnesium compounds hold for use in the “Fischer–Tropsch-like” transformation of CO/H2 mixtures to value added oxygenate products.
Published: 2015
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262. Calcium Hydride Catalyzed Highly 1,2‐Selective Pyridine Hydrosilylation

Author: Jürgen Pahl, Heiko Bauer, Julia Intemann, Sjoerd Harder, Laurent Maron, Stratingh Institute for Chemistry, University of Groningen [Groningen], Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), 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), 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: calcium, Calcium hydride, 010405 organic chemistry, Hydrosilylation, Hydride, Organic Chemistry, Inorganic chemistry, Magnesium hydride, hydrosilylation, hydride, reduction, General Chemistry, 010402 general chemistry, 01 natural sciences, Medicinal chemistry, Catalysis, 0104 chemical sciences, chemistry.chemical_compound, chemistry, Pyridine, Picoline, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Isoquinoline, Homoleptic
Abstract: International audience; Reaction of the calcium hydride complex (DIPPnacnac‐CaH⋅THF)2 with pyridine is much faster and selective than that of the corresponding magnesium hydride complex (DIPPnacnac = [(2,6‐iPr2C6H3)NC(Me)]2CH). With a range of pyridine, picoline and quinoline substrates, exclusive transfer of the hydride ligand to the 2‐position is observed and also at higher temperatures no 1,2→1,4 isomerization is found. The heteroleptic product DIPPnacnac‐Ca(1,2‐dihydropyridide)⋅(pyridine) shows fast ligand exchange into homoleptic calcium complexes and therefore could not be isolated. Calcium hydride reduction of isoquinoline gave well‐defined homoleptic products which could be characterized by X‐ray diffraction: Ca(1,2‐dihydroisoquinolide)2⋅(isoquinoline)4 and Ca3(1,2‐dihydroisoquinolide)6⋅(isoquinoline)6. The striking selectivity difference in the dearomatization of pyridines by Mg or Ca complexes could be explained by DFT theory and was utilized in catalysis. Whereas hydroboration of pyridine with pinacol borane with a calcium hydride catalyst gave only minor conversion, the hydrosilylation of pyridine and quinolines with PhSiH3 yields exclusively 1,2‐dihydropyridine and 1,2‐dihydroquinoline silanes with 80–90 % conversion. Similar results can be achieved with the catalyst Ca[N(SiMe3)2]2⋅(THF)2. These calcium complexes represent the first catalysts for the 1,2‐selective hydrosilylation of pyridines.
Published: 2015
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263. A Dimetalloxycarbene Bonding Mode and Reductive Coupling Mechanism for Oxalate Formation from CO2

Author: Thomas P. Spaniol, Jun Okuda, Laurent Maron, Jared S. Silvia, Christopher C. Cummins, Christos E. Kefalidis, and Albert Paparo
Subjects: Stereochemistry, Carbon fixation, Cationic polymerization, chemistry.chemical_element, General Chemistry, Catalysis, Oxalate, chemistry.chemical_compound, Crystallography, Deprotonation, chemistry, Molecule, Formate, Carbene, Titanium
Abstract: We describe the stable and isolable dimetalloxycarbene [(TiX3 )2 (μ2 -CO2 -κ(2) C,O:κO')] 5, where X=N-(tert-butyl)-3,5-dimethylanilide, which is stabilized by fluctuating μ2 -κ(2) C,O:κ(1) O' coordination of the carbene carbon to both titanium centers of the dinuclear complex 5, as shown by variable-temperature NMR studies. Quantum chemical calculations on the unmodified molecule indicated a higher energy of only +10.5 kJ mol(-1) for the μ2 -κ(1) O:κ(1) O' bonding mode of the free dimetalloxycarbene compared to the μ2 -κ(2) C,O:κ(1) O' bonding mode of the masked dimetalloxycarbene. The parent cationic bridging formate complex [(TiX3 )2 (μ2 -OCHO-κO:κO')][B(C6 F5)4], 4[B(C6 F5)4], was simply deprotonated with the strong base K(N(SiMe3 )2 ) to give 5. Complex 5 reacts smoothly with CO2 to generate the bridging oxalate complex [(TiX3 )2 (μ2 -C2 O4 -κO:κO'')], 6, in a C-C bond formation reaction commonly anticipated for oxalate formation by reductive coupling of CO2 on low-valent transition-metal complexes.
Published: 2015
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264. Ein Dimetalloxycarben-Bindungsmodus und der reduktive Kupplungsmechanismus zur Bildung von Oxalat ausgehend von CO2

Author: Christos E. Kefalidis, Albert Paparo, Laurent Maron, Thomas P. Spaniol, Jun Okuda, Jared S. Silvia, and Christopher C. Cummins
Subjects: General Medicine
Abstract: Wir beschreiben ein stabiles, isolierbares Dimetalloxycarben [(TiX3)2(μ2-CO2-κ2C,O:κO′)], 5 (X=N-(tert-Butyl)-3,5-dimethylanilid), das NMR-spektroskopischen Studien bei variabler Temperatur zufolge durch fluktuierende μ2-κ2C,O: κ1O′-Koordination des Carben-C-Atoms an beide Ti-Zentren des zweikernigen Komplexes 5 stabilisiert wird. Quantenchemische Rechnungen am unmodifizierten Molekul lassen auf eine hohere Energie von nur +10.5 kJ mol−1 fur den μ2-κ1O: κ1O′-Bindungsmodus des freien Dimetalloxycarbens gegenuber dem μ2-κ2C,O:κ1O′-Bindungsmodus des maskierten Dimetalloxycarbens schliesen. Der kationische Ausgangskomplex [(TiX3)2(μ2-OCHO-κO:κO′)][B(C6F5)4], 4[B(C6F5)4], mit verbruckendem Formiatliganden wurde einfach mit der starken Base K(N(SiMe3)2) zu 5 deprotoniert. Komplex 5 reagiert glatt mit CO2 zum verbruckten Oxalatkomplex [(TiX3)2(μ2-C2O4-κO:κO′′)], 6, in einer C-C-bindungsbildenden Reaktion, die allgemein fur die Oxalatbildung durch reduktive Kupplung von CO2 an niedervalenten Ubergangsmetallkomplexen erwartet wird.
Published: 2015
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265. Coordination of a Triphosphine–Silane to Gold: Formation of a Trigonal Pyramidal Complex Featuring Au+→Si Interaction

Author: Maxime Mercy, Abderrahmane Amgoune, Sonia Mallet-Ladeira, Didier Bourissou, Laurent Maron, Hajime Kameo, Hiroshi Nakazawa, and Pauline Gualco
Subjects: Tetracoordinate, 010405 organic chemistry, Stereochemistry, Chemistry, Organic Chemistry, Cationic polymerization, Trigonal pyramidal molecular geometry, Nuclear magnetic resonance spectroscopy, 010402 general chemistry, 01 natural sciences, Silane, 0104 chemical sciences, 3. Good health, Inorganic Chemistry, chemistry.chemical_compound, Crystallography, Lewis acids and bases, Physical and Theoretical Chemistry, Phosphine
Abstract: Coordination of the triphosphine–fluorosilane [o-(iPr2P)C6H4]3SiF to AuCl results in the formation of a trigonal pyramidal cationic complex. Though cationic, the gold center acts as a Lewis base and is engaged in significant Au→Si interaction, as substantiated by X-ray diffraction and NMR spectroscopy. In solution, the P,P,P,Si tetracoordinate cationic complex coexists with a neutral P,P,Cl tricoordinate form, with a pendant phosphine buttress and without Au→Si interaction. The bonding situation in the two isomeric forms has been assessed by DFT calculations. Coordination of the third phosphine arm is shown to induce cationization and to play a key role in the presence of the Au→Si interaction.
Published: 2015
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266. Hydroboration of Carbon Dioxide Using Ambiphilic Phosphine–Borane Catalysts: On the Role of the Formaldehyde Adduct

Author: Laurent Maron, Nicolas Bouchard, Karine Syrine Nahi, Ghenwa Bouhadir, Marc-André Légaré, Richard Declercq, Didier Bourissou, Frédéric-Georges Fontaine, and Marc-André Courtemanche
Subjects: Pinacol, General Chemistry, Borane, Medicinal chemistry, Catalysis, Frustrated Lewis pair, Adduct, chemistry.chemical_compound, Hydroboration, chemistry, 13. Climate action, Organic chemistry, Moiety, Phosphine
Abstract: Ambiphilic phosphine–borane derivatives 1-B(OR)2-2-PR′2–C6H4 (R′ = Ph (1), iPr (2); (OR)2 = (OMe)2 (1a, 2a); catechol (1b, 2b) pinacol (1c, 2c), −OCH2C(CH3)2CH2O– (1d)) were tested as catalysts for the hydroboration of CO2 using HBcat or BH3·SMe2 to generate methoxyboranes. It was shown that the most active species were the catechol derivatives 1b and 2b. In the presence of HBcat, without CO2, ambiphilic species 1a, 1c, and 1d were shown to transform to 1b, whereas 2a and 2c were shown to transform to 2b. The formaldehyde adducts 1b·CH2O and 2b·CH2O are postulated to be the active catalysts in the reduction of CO2 rather than being simple resting states. Isotope labeling experiments and density functional theory (DFT) studies show that once the formaldehyde adduct is generated, the CH2O moiety remains on the ambiphilic system through catalysis. Species 2b·CH2O was shown to exhibit turnover frequencies for the CO2 reduction using BH3·SMe2 up to 228 h–1 at ambient temperature and up to 873 h–1 at 70 °C, mir...
Published: 2015
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267. Diskrete Magnesiumhydrid-Aggregate: ein kationischer Mg13H18-Cluster, stabilisiert durch einen NNNN-Makrocyclus

Author: Thomas P. Spaniol, Jun Okuda, Silvia Schnitzler, Klaus Beckerle, Daniel Martin, and Laurent Maron
Subjects: Chemistry, General Medicine
Published: 2015
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268. Oxygen-Oxygen Bond Cleavage and Formation in Co(II)-Mediated Stoichiometric O-2 Reduction via the Potential Intermediacy of a Co(IV) Oxyl Radical

Author: Denis M. Spasyuk, Warren E. Piers, Laura Fairburn, Laurent Maron, Lucie Nurdin, Department of Chemistry, University of Calgary, University of Calgary, Canadian Light Source Inc., University of Saskatchewan [Saskatoon] (U of S), 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), Natural Sciences and Engineering Research Council of Canada, French CNRS PICS project, Alberta Innovates Technology Futures, and Vanier Canada Graduate Scholarships
Subjects: 010405 organic chemistry, Ligand, Dimer, chemistry.chemical_element, Protonation, General Chemistry, 010402 general chemistry, Photochemistry, 7. Clean energy, 01 natural sciences, Biochemistry, Oxygen, Catalysis, 0104 chemical sciences, Metal, chemistry.chemical_compound, Colloid and Surface Chemistry, chemistry, visual_art, visual_art.visual_art_medium, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Metal aquo complex, Bond cleavage
Abstract: International audience; In reactions of significance to alternative energy schemes, metal catalysts are needed to overcome kinetically and thermodynamically difficult processes. Often, high-oxidation-state, high-energy metal oxo intermediates are proposed as mediators in elementary steps involving O-O bond cleavage and formation, but the mechanisms of these steps are difficult to study because of the fleeting nature of these species. Here we utilized a novel dianionic pentadentate ligand system that enabled a detailed mechanistic investigation of the protonation of a cobalt(III)-cobalt(III) peroxo dimer, a known intermediate in oxygen reduction catalysis to hydrogen peroxide. It was shown that double protonation occurs rapidly and leads to a low-energy O-O bond cleavage step that generates a Co(III) aquo complex and a highly reactive Co(IV) oxyl cation. The latter was probed computationally and experimentally implicated through chemical interception and isotope labeling experiments. In the absence of competing chemical reagents, it dimerizes and eliminates dioxygen in a step highly relevant to O-O bond formation in the oxygen evolution step in water oxidation. Thus, the study demonstrates both facile O-O bond cleavage and formation in the stoichiometric reduction of O-2 to H2O with 2 equiv of Co(II) and suggests a new pathway for selective reduction of O-2 to water via Co(III)-O-O-Co(III) peroxo intermediates.
Published: 2018
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269. Hydration of CH3HgOH and CH3HgCl compared to HgCl2, HgClOH, and Hg(OH)(2): A DFT microsolvation cluster approach

Author: Humberto Saint-Martin, Alejandro Ramírez-Solís, J. I. Amaro-Estrada, Jorge Hernández-Cobos, Laurent Maron, Universidad Nacional Autónoma de México = National Autonomous University of Mexico (UNAM), 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), Universidad Autonoma del Estado de Morelos (UAEM), UNAM-DGAPA, CONACYT Basic Science Project [253679], DGAPA-UNAM [IN101599, IG100416], and [LANCAD-UNAM-DGTIC-057]
Subjects: Aqueous solution, 010304 chemical physics, Chemistry, General Physics and Astronomy, 010402 general chemistry, 01 natural sciences, Spectral line, 0104 chemical sciences, Gibbs free energy, Molecular dynamics, symbols.namesake, Solvation shell, 0103 physical sciences, symbols, Physical chemistry, Moiety, Molecule, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Physical and Theoretical Chemistry, Absorption (chemistry)
Abstract: International audience; We address the aqueous microsolvation of the CH3HgCl and CH3HgOH molecules using a stepwise hydration scheme including up to 33 water molecules and compare our results with the previously studied HgCl2, HgClOH, and Hg(OH)(2) complexes. Optimized geometries and Gibbs free energies were obtained at the B3PW91/aug-RECP(Hg)-6-31G(d,p) level. At least 33 water molecules were required to build the first solvation shell around both methylmercury compounds. Optimized geometries were found having favorable interactions of water molecules with Hg, Cl, and the OH moiety. Born-Oppenheimer molecular dynamics simulations were performed on the largest CH3HgX (X = Cl, OH)-(H2O)(33) clusters at the same level of theory. Born-Oppenheimer molecular dynamics simulations at T = 300 K (ca. 0.62 kcal/mol) revealed the presence of configurations with hydrogenbonded networks that include the OH moiety in CH3HgOH and exclude both the Hg and Cl in CH3HgCl, favoring a clathrate-type structure around the methyl moiety. The comparison to the microsolvated HgClOH, Hg(OH)(2), and HgCl2 molecules showed that, in all cases, the water molecules easily move away from Cl, thus supporting the idea that HgCl2 behaves as a non-polar solute. The theoretical (LIII edge) X-ray absorption near edge structure spectra are obtained and found in good agreement with experimental data, especially for the CH3HgCl species. Published by AIP Publishing.
Published: 2018
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270. Dinitrogen functionalization at a ditantalum center. Balancing N-2 displacement and N-2 functionalization in the reaction of coordinated N-2 with CS2

Author: Michael D. Fryzuk, Laurent Maron, Ludovic Castro, Richard J. Burford, Jason E. Hein, University of British Columbia [Vancouver], SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé (SYMMES), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), 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 British Columbia, Natural Sciences and Engineering Research Council (NSERC) of Canada (Engage, Discovery), Canada Foundation for Innovation [35833], NSERC of Canada for a Discovery Grant, Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)
Subjects: chemistry.chemical_classification, Carbon disulfide, Sulfide, 010405 organic chemistry, 010402 general chemistry, 01 natural sciences, 3. Good health, 0104 chemical sciences, Inorganic Chemistry, chemistry.chemical_compound, chemistry, parasitic diseases, Polymer chemistry, Molecule, Surface modification, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Methylene, Bond cleavage
Abstract: International audience; The reaction of carbon disulfide (CS2) with the side-on end-on dinitrogen complex ([NPNSi]Ta)(2)(-(1):(2)-N-2)(-H)(2) (1) (where [NPNSi] = [PhP(CH2SiMe2NPh)(2)]) has been studied and shown to generate two products, the ratio of which depends on the concentration of added carbon disulfide. At high concentrations of CS2, N-N bond cleavage and functionalization occur to generate a ditantalum complex with an isothiocyanato ligand N-bound to Ta along with bridging sulfido and nitrido moieties. At lower concentrations of CS2, less dinitrogen functionalization is observed; instead, N-2 is displaced and the CS2 molecule is completely disassembled to generate a ditantalum derivative with bridging methylene and two sulfide moieties. Kinetic and DFT studies have been performed and provide clues about the product ratio and mechanistic information and shed light on why N-2 functionalization is challenging.
Published: 2018
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271. (C5Me5)(2)Y(mu-H)(mu-CH2C5Me4)Y(C5Me5) as a reservoir of electrons for the reduction of PhSSPh and CO2: A theoretical study

Author: Ludovic Castro, Laurent Maron, SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé (SYMMES), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), 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 de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Reaction mechanism, 010405 organic chemistry, Chemistry, Ligand, Hydride, Organic Chemistry, 010402 general chemistry, Metathesis, 01 natural sciences, Biochemistry, DFT, Reduction of CO2, 0104 chemical sciences, Inorganic Chemistry, chemistry.chemical_compound, Crystallography, Computational chemistry, Materials Chemistry, Molecule, Moiety, Chemical stability, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Physical and Theoretical Chemistry, Methylene
Abstract: International audience; Reaction mechanisms for the reduction of PhSSPh and CO2 by the trivalent yttrium tuck-over hydride complex (C5Me5)(2)Y(mu-H)(mu-CH2C5Me4)Y(C5Me5) (1) have been investigated by means of DFT methods. Complex 1 can be seen as a reservoir of electrons able to deliver two electrons to a substrate by combining its hydride ligand with its tuck-over methylene moiety to form a (C5Me5)(-) ligand. The study shows that CO2 should be effectively reduced by complex 1. A two-steps metathesis process is found as the likely mechanism for the synthesis of both [(C5Me5)(2)Y(mu-SPh)](2) and [(C5Me5)(2)Y](2) (mu-CO2). The latter complex can further react with another CO2 molecule to generate either a carbonate or an oxalate sandwiched complex. However, the high thermodynamic stability of the latter should favor its exclusive formation. (C) 2017 Published by Elsevier B.V.
Published: 2018
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272. Mechanism and Effect of Polar Styrenes on Scandium-Catalyzed Copolymerization with Ethylene

Author: Laurent Maron, Dongtao Liu, Kening Qiao, Zhigang Xie, Bo Liu, Jian Fang, Tiantian Wang, Dongmei Cui, Zichuan Wang, State Key Laboratory of Polymer Physics and Chemistry, Graduate School of the Chinese Academy of Sciences (GSCAS), Chinese Academy of Sciences [Changchun Branch] (CAS)-Chinese Academy of Sciences [Changchun Branch] (CAS), Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, Lanzhou University, 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), National Natural Science Foundation of China [21634007, 51673184], and MST [2015CB654702]
Subjects: Ethylene, 010405 organic chemistry, copolymerization, inductive effects, polyolefins, rare-earth metal, scandium, Comonomer, Substituent, chemistry.chemical_element, General Chemistry, Nuclear magnetic resonance spectroscopy, General Medicine, 010402 general chemistry, Medicinal chemistry, 01 natural sciences, Catalysis, 0104 chemical sciences, chemistry.chemical_compound, Monomer, chemistry, Copolymer, Scandium, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Inductive effect
Abstract: International audience; Copolymerization of ethylene (E) and polar vinyl monomers remains a problem because E propagation is hindered. Herein, for the first time, we report the copolymerization of E and polar styrenes (S-R) by using an oxophilic scandium catalyst that exhibits higher turnover frequencies than both E and S-R homopolymerizations when R is an electron-withdrawing group. This positive comonomer effect was elucidated through computing reaction profiles of E/S-F copolymerization at the DFT (B3PW91) level of theory. It reveals that the secondary interaction between Sc3+ and phenyl of the last and penultimate inserted S-F units leads to a decrease of the E insertion barrier, because the electron-withdrawing substituent enhances the electrophilicity of Sc3+ by an inductive effect mediated by the secondary interaction. After three consecutive insertions of the E units, the secondary interaction is lost and the S-F insertion is kinetically preferred over the E insertion. This process is in line with the NMR spectrum analyses which show that the resultant copolymers mainly contain S-R(E)(x)S-R sequences where x
Published: 2018
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273. Coordination of arenes and phosphines by charge separated alkaline earth cations

Author: Mathew D. Anker, Laurent Maron, Mary F. Mahon, Lucia Garcia, Michael S. Hill, Department of Chemistry [Bath], University of Bath [Bath], 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), EPSRC (UK) [EP/N014456/1], and EPSRC [EP/N014456/1] Funding Source: UKRI
Subjects: Valence (chemistry), 010405 organic chemistry, Chemistry, Phosphide, Fluorobenzene, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, Adduct, Inorganic Chemistry, Bond length, Crystallography, chemistry.chemical_compound, Molecule, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Triphenylphosphine, Benzene
Abstract: International audience; Generation of beta-diketiminato group 2 cations, [((BDI)-B-Me)Ae](+) and [(t-BuBDI)Ae](+) ((BDI)-B-Me = HC{(Me)CN-2,6-i-Pr2C6H3}(2); t-BuBDI = HC{(t-Bu)CN-2,6-i-Pr2C6H3}(2); Ae = Mg or Ca), in conjunction with the weakly coordinating anion, [Al{OC(CF3)(3)}(4)](-), allows the characterisation of charge separated alkaline earth eta(6)-pi adducts to toluene or benzene when crystallised from the arene solvents. Addition of 1,4-difluorobenzene to [((BDI)-B-Me)Mg](+) results in the isolation of [((BDI)-B-Me)Mg(1,4-F2C6H4)(3)](+) in which the fluorobenzene molecules coordinate via kappa(1)-F-M interactions. Although DFT analysis indicates that the polyhapto arene binding to Mg is effectively electrostatic in origin, the interactions with Ca (Sr and Ba) are observed to invoke small but significant pi overlap of the arene HOMOs with the alkaline earth valence nd orbitals. Reaction of triphenylphosphine with [((BDI)-B-Me)Mg](+) and [(t-BuBDI)Mg](+) in toluene solvent allows the isolation of the respective terminally coordinated magnesium-phosphine adducts. The resultant Mg-P bond lengths [2.5972(13), 2.6805(12) angstrom] are comparable to those previously observed in magnesium derivatives of terminal but formally anionic phosphide ligands, while the effectively electrostatic nature of the bonding is supported by DFT calculations.
Published: 2018
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274. The Nature of the Heavy Alkaline Earth Metal-Hydrogen Bond: Synthesis, Structure, and Reactivity of a Cationic Strontium Hydride Cluster

Author: Thomas P. Spaniol, Jun Okuda, Thomas Höllerhage, Debabrata Mukherjee, Valeri Leich, Laurent Maron, Ulli Englert, Rhein Westfal TH Aachen, Institute of Inorganic Chemistry [Aachen] (IAC RWTH), Rheinisch-Westfälische Technische Hochschule Aachen University (RWTH), 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), Deutsche Forschungsgemeinschaft through the International Research Training Group 'Selectivity in Chemo- and Biocatalysis', and Alexander von Humboldt Foundation
Subjects: Alkaline earth metal, Strontium, 010405 organic chemistry, Hydrogen bond, Chemistry, Hydride, chemistry.chemical_element, General Chemistry, 010402 general chemistry, 01 natural sciences, Biochemistry, Redox, Medicinal chemistry, Catalysis, 0104 chemical sciences, chemistry.chemical_compound, Colloid and Surface Chemistry, Hydrogenolysis, Hydroxide, Amine gas treating, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph]
Abstract: International audience; The molecular strontium hydride [(Me(3)TACD)(3)Sr-3(mu(3)-H)(2)][SiPh3] (2) was isolated as the dark red benzene solvate 2 center dot C6H6 in 69% yield from the reaction of [Sr(SiPh3)(2)(thf)(3)] (1') with (Me(3)TACD)H (1,4,7-trimethyl-1,4,7,10-tetraazacyclododecane). This reaction can be considered as a redox process, with the Bronsted acidic amine proton in (Me(3)TACD)H transformed into the hydride by the anion [SiPh3](-). Trace amounts of water resulted in the formation of [(Me(3)TACD)(3)Sr-3(mu(3)-H)(mu(3)-OH)][SiPh3] (2*), which cocrystallized with 2. Single-crystal X-ray diffraction of 2 revealed a substitutional disorder of a bridging hydride with a hydroxide ligand. Hydride complex 2 was also obtained by hydrogenolysis of [(Me(3)TACD)Sr(SiPh3)] (3), although pure 3 proved difficult to isolate. In the presence of a 2-fold excess of (Me(3)TACD)H, the reaction with disilyl 1' gave [(Me(3)TACD)SiPh3] (4). Complex 2 underwent facile H/D exchange with D-2 (1 bar), with the anion [SiPh3]- decomposing concurrently. In the reaction of 2 with 1,1-diphenylethylene (DPE), the anion [SiPh3](-) was added to the C-C bond in DPE to give [(Me(3)TACD)(3)Sr3H2][Ph2CCH2SiPh3] (5), whereas the cationic cluster [(Me(3)TACD)(3)Sr3H2](+) remained unchanged. 9-Fluorenone underwent one-electron reduction with 2 to give the paramagnetic ketyl complex [{(Me(3)TACD)H}Sr(OC13H8 center dot)(2)(thf)(2)] (6). These strontium compounds are structurally similar to the lighter calcium congeners, but more reactive, in particular with regard to fast H/D exchange and [SiPh3]- anion decomposition. DFT studies on the cationic hydride clusters suggest a more pronounced covalent character for strontium compared to calcium. Disilyl 1, strontium diketyl 6, and the calcium congener of 6, [{(Me(3)TACD)H}Ca(OC13H8 center dot)(2)] (10), were also characterized by X-ray diffraction.
Published: 2018
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275. Reversing Conventional Reactivity of Mixed Oxo/Alkyl Rare-Earth Complexes: Non-Redox Oxygen Atom Transfer

Author: Linhong Weng, Iker del Rosal, Haiwen Tian, Jianquan Hong, Laurent Maron, Xigeng Zhou, Lixin Zhang, Fudan University [Shanghai], 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), National Natural Science Foundation of China [21372047, 21672038, 21572034, 21732007], and 973 program [2015CB856600]
Subjects: chemistry.chemical_classification, 010405 organic chemistry, Ligand, General Medicine, General Chemistry, 010402 general chemistry, 01 natural sciences, Redox, Combinatorial chemistry, Catalysis, 0104 chemical sciences, Metal, Oxygen atom, cluster compounds, organometallic chemistry, oxygen atom transfer, rare-earth complexes, theoretical chemistry, chemistry, visual_art, visual_art.visual_art_medium, Cluster (physics), Oxophilicity, Reactivity (chemistry), [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Alkyl
Abstract: International audience; The preferential substitution of oxo ligands over alkyl ones of rare-earth complexes is commonly considered as "impossible" due to the high oxophilicity of metal centers. Now, it has been shown that simply assembling mixed methyl/oxo rare-earth complexes to a rigid trinuclear cluster framework cannot only enhance the activity of the Ln-oxo bond, but also protect the highly reactive Ln-alkyl bond, thus providing a previously unrecognized opportunity to selectively manipulate the oxo ligand in the presence of numerous reactive functionalities. Such trimetallic cluster has proved to be a suitable platform for developing the unprecedented non-redox rare-earth-mediated oxygen atom transfer from ketones to CS2 and PhNCS. Controlled experiments and computational studies shed light on the driving force for these reactions, emphasizing the importance of the sterical accessibility and multimetallic effect of the cluster framework in promoting reversal of reactivity of rare-earth oxo complexes.
Published: 2018
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276. Steric control in the metal-ligand electron transfer of iminopyridine-ytterbocene complexes

Author: Alexander A. Trifonov, Boris G. Shestakov, Tatyana V. Mahrova, Lapo Luconi, Giuliano Giambastiani, Dmitry M. Lyubov, Anton V. Cherkasov, Lorenzo Sorace, Elisa Louyriac, Laurent Maron, Georgii K. Fukin, Konstantin A. Lyssenko, Siberian Branch of the Russian Academy of Sciences (SB RAS), CNR - Institute for Chemistry of Organometallic Compounds, Sesto Fiorentino, Università degli Studi di Firenze = University of Florence (UniFI), 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), and Russian Science Foundation [17-73-30036]
Subjects: chemistry.chemical_classification, Steric effects, Agostic interaction, Iminopyridine-Ytterbocene Complexes, Coordination sphere, Denticity, 010405 organic chemistry, Ligand, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, Coordination complex, Inorganic Chemistry, Metal-Ligand Electron Transfer, Electron transfer, Crystallography, chemistry.chemical_compound, chemistry, Pyridine, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph]
Abstract: International audience; A systematic study of reactions between Cp*Yb-2(THF) (Cp* = eta(5)-C5Me5, 1) and iminopyridine ligands (IPy = 2,6-(Pr2C6H3N)-Pr-i=CH(C5H3N-R), R = H (2a), 6-C4H3O (2b), 6-C4H3S (2c), 6-C6H5 (2d)) featuring similar electron accepting properties but variable denticity and steric demand, has provided a new example of steric control on the redox chemistry of ytterbocenes. The reaction of the unsubstituted IPy 2a with 1, either in THF or toluene, gives rise to the paramagnetic species Cp*Yb-2(III)(IPy)(center dot-) (3a) as a result of a formal one-electron oxidation of the Yb-II ion along with IPy reduction to a radical-anionic state. The reactions of 1 with substituted iminopyridines 2b-d, bearing aryl or hetero-aryl dangling arms on the 6 position of the pyridine ring occur in a non-coordinating solvent (toluene) only and afford coordination compounds of a formally divalent ytterbium ion, coordinated by neutral IPy ligands Cp*Yb-2(II)(IPy)(0) (3b-d). The X-ray diffraction studies revealed that 2a-c act as bidentate ligands; while the radical-anionic IPy in 3a chelates the Yb-III ion with both nitrogens, neutral IPy ligands in 3b and 3c participate in the metal coordination sphere through the pyridine nitrogen and O or S atoms from the furan or thiophene moieties, respectively. Finally, in complex 3d the neutral IPy ligand formally adopts a monodentate coordination mode. However, an agostic interaction between the Yb-II ion and an ortho C-H bond of the phenyl ring has been detected. Imino-nitrogens in 3b-d are not involved in the metal coordination. Variable temperature magnetic measurements on 3a are consistent with a multiconfigurational ground state of the Yb ion and suggest that the largest contribution arises from the 4f(13)-radical configuration. For complexes 3b and 3c the data of magnetic measurements are indicative of a Yb-II-closed shell ligand electronic distribution. Complex 3d is characterized by a complex magnetic behavior which does not allow for an unambiguous estimation of its electronic structure. The results are rationalized using DFT and CSSCF calculations. Unlike diazabutadiene analogues, 3a does not undergo a solvent mediated metalligand electron transfer and remains paramagnetic in THF solution. On the other hand, complexes 3b-d readily react with THF to afford 1 and free IPy 2b-d.
Published: 2018
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277. Side Arm Twist on Zn-Catalyzed Hydrosilylative Reduction of CO2 to Formate and Methanol Equivalents with High Selectivity and Activity

Author: Laurent Maron, Chongyang Du, Yaofeng Chen, Iker del Rosal, Guangyu Li, Xuebing Leng, Eugene Y.-X. Chen, Li Xiang, Guoqin Feng, University of Chinese Academy of Sciences [Beijing] (UCAS), Shanghai Institute of Organic Chemistry (SIOC), Chinese Academy of Sciences [Beijing] (CAS), 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), Colorado State Univ, Dept Bioagr Sci & Pest Management, Ft Collins, CO 80523 USA, Partenaires INRAE, National Natural Science Foundation of China [21732007, 21602237], HPCs CALcul en Midi-Pyrenees (CALMIP-EOS grant) [1415], and NSF [CHE-1507702]
Subjects: Silylation, 010405 organic chemistry, Hydrosilylation, Siloxide, chemistry.chemical_element, General Chemistry, Zinc, 010402 general chemistry, CO2 reduction, DFT, hydrosilylation, zinc catalyst, pendant donor, 01 natural sciences, Combinatorial chemistry, Catalysis, 0104 chemical sciences, chemistry.chemical_compound, chemistry, Formate, Selective reduction, Methanol, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph]
Abstract: International audience; Reductive hydrosilylation of CO2 by catalysts based on environmentally benign metals such as zinc still presents an unmet challenge in terms of catalyst selectivity and activity. Here we show that tetra-coordinated neutral zinc siloxide complexes supported by the beta-diketiminato ligand bearing a pendant amine arm exhibit unprecedentedly high catalytic activity toward the selective reduction of CO2 by a hydrosilane to silyl formate. More significantly, this zinc catalyst system can also effectively catalyze the subsequent reduction of silyl formate into methoxysilane in quantitative yield. To understand the mechanism of the CO2 hydrosilylation and the influence of the side arm, a series of catalytic active species (or intermediates), zinc hydrides, and formates, has been synthesized and structurally characterized; the relevant stoichiometric reactions and kinetic study were performed. DFT calculations were also carried out to determine the reaction profiles for the CO2 hydrosilylation and to explain the relative activity of the zinc catalysts employed in this study. This combined experimental and theoretical study gives insights into the critical effects of the pendant amine donor arm and the size of the alkyl group of the amine on the relative energetics of the species involved in the proposed catalytic cycle.
Published: 2018
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278. The 'Wanderlust' of Me3Si groups in rare-earth triple-decker complexes: a combined experimental and computational study

Author: Frank T. Edelmann, Liane Hilfert, Felix Engelhardt, Phil Liebing, Sabine Busse, Volker Lorenz, Adrien Bathelier, Laurent Maron, Otto Von Guericke Univ, 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), and Otto-von-Guericke-Universität Magdeburg = Otto-von-Guericke University [Magdeburg] (OVGU)
Subjects: Trimethylsilyl, 010405 organic chemistry, Stereochemistry, Rare earth, Metals and Alloys, General Chemistry, 010402 general chemistry, 01 natural sciences, Catalysis, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, chemistry.chemical_compound, chemistry, Materials Chemistry, Ceramics and Composites, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph]
Abstract: International audience; The migration of Me3Si groups (Wanderlust) in rare-earth triple-decker sandwich complexes of the type Ln(2)(COT)(3) (COT = bis(trimethylsilyl)cyclooctatetraenyl) has been elucidated by a combined experimental and computational study. For the first time, two isomers of a Ln(2)(COT)(3) triple-decker have been isolated and characterized in the case of Y-2(COT)(3).
Published: 2018
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279. Amido Analogues of Nonbent Lanthanide (II) and Calcium Metallocenes. Heterolytic Cleavage of π-Bond Ln–Carbazolyl Ligand Promoted by Lewis Base Coordination

Author: Laurent Maron, Anton V. Cherkasov, Iker del Rosal, Georgy K. Fukin, Alexander A. Trifonov, and Alexander N. Selikhov
Subjects: Lanthanide, Steric effects, Chemistry, Ligand, Organic Chemistry, Ionic bonding, Photochemistry, Heterolysis, Dissociation (chemistry), Inorganic Chemistry, Crystallography, Lewis acids and bases, Physical and Theoretical Chemistry, Lone pair
Abstract: Introduction of four tBu groups into a carbazol-yl framework leads to switching of the metal–ligand bonding in the Ln(II) and Ca complexes from σ to π. Complexes [(tBu4Carb)2Ln] (Ln = Sm, Eu, Yb, Ca) are amido analogues of metallocenes, which adopt the sandwich structures with parallel disposition of the aromatic ligands and strong contribution of η3-mode into η5 metal–ligand bonding. The DFT calculations demonstrated that the geometry is due to steric effects (presence of the bulky tBu groups) as well as the maximization of the overlap between the Sm 4f orbital and the π-type nitrogen lone pair of the carbazol-yl ligand. Coordination of DME to the metal centers in [(tBu4Carb)2M] (M = Sm, Yb) results in the heterolytic dissociation of the metal–ligand π-bond and the formation of ionic complexes [tBu4Carb–]2[Ln2+(DME)n].
Published: 2015
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280. A Scandium Complex Bearing Both Methylidene and Phosphinidene Ligands: Synthesis, Structure, and Reactivity

Author: Tengfei Li, Laurent Maron, Yaofeng Chen, Jiliang Zhou, Xuebing Leng, and Shanghai Institute of Organic Chemistry - Chinese Academy of Sciences
Subjects: Nucleophilic addition, Ligand, Isocyanide, Organic Chemistry, chemistry.chemical_element, Photochemistry, Medicinal chemistry, Inorganic Chemistry, Benzonitrile, chemistry.chemical_compound, chemistry, Covalent bond, Phosphinidene, Reactivity (chemistry), [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Scandium, Physical and Theoretical Chemistry
Abstract: International audience; The scandium complex bearing both methylidene and phosphinidene ligands, [(LSc) 2 (μ 2-CH 2)(μ 2-PDIPP)] (L = [MeC(NDIPP)CHC(NDIPP)Me] − , DIPP = 2,6-(i Pr) 2 C 6 H 3) (2), has been synthesized, and its reactivity has been investigated. Reaction of scandium methyl phosphide [LSc(Me){P(H)DIPP}] with 1 equiv of scandium dimethyl complex [LScMe 2 ] in toluene at 60 °C provided complex 2 in good yield, and the structure of complex 2 was determined by single-crystal X-ray diffraction. Complex 2 easily undergoes nucleophilic addition reactions with CO 2 , CS 2 , benzonitrile, and tert-butyl isocyanide. In the above reactions, the unsaturated substrates insert into the Sc−C(methylidene) bond to give some interesting dianionic ligands while the Sc−P(phosphinidene) bond remains untouched. The bonding situation of complex 2 was analyzed using DFT methods, indicating a more covalent bond between the scandium ion and the phosphinidene ligand than between the scandium ion and the methylidene ligand. ■ INTRODUCTION Alkylidene (or carbene) and phosphinidene complexes of transition metals have attracted intense interest and been extensively studied in the past decades. 1,2 The research on such complexes has revealed rich reactivity and applications in group-transfer and catalytic reactions. One exception is those complexes with rare-earth metal (Sc, Y, and lanthanide metal) ions. Rare-earth metal ions are among the hardest Lewis acids, whereas alkylidene and phosphinidene ligands are soft Lewis bases; thus, the rare-earth metal−alkylidene (or phosphini-dene) coordination is mismatched based on the Pearson's HSAB principle. 3 Up to now, the rare-earth metal alkylidene and phosphinidene complexes remain limited. 4−6 The reactivity study showed that most of the rare-earth metal alkylidene and phosphinidene complexes can react as the alkylidene or phosphinidene transfer agents with ketones to give alkenes or phosphaalkenes. 4 It was also found that some of the rare-earth metal alkylidene and phosphinidene complexes undergo nucleophilic addition reactions with unsaturated substrates, such as CO, isocyanate, carbodiimide, and isocyanide. 5k,l,6f,g We have developed a type of β-diketiminato based tridentate ligands, which can stabilize a series of rare-earth metal dialkyl complexes, 7 and a scandium terminal imido complex. 8 Recently, we obtained a scandium bridged phosphinidene complex [{MeC(NDIPP)CHC(Me)NCH 2 CH 2 N(i Pr) 2 }Sc{μ-PC 6 H 3-(2,6-Me 2)}] 2 (DIPP = 2,6-(i Pr) 2 C 6 H 3)), in which the pendant arm of the tridentate ligand is not coordinated to the scandium ion due to the phosphinidene ligand having a strong tendency to bridge two or more rare-earth metal centers. 6f Thus, we carried out a study to synthesize a scandium phosphinidene complex supported by the bulky β-diketiminato ligand, [MeC(NDIPP)CHC(NDIPP)Me] − (DIPP = 2,6-(i Pr) 2 C 6 H 3). 9 During this study, we obtained an unprecedented scandium complex which bears both phosphinidene and methylidene ligands. This scandium methylidene phosphini-dene complex reacts with a variety of unsaturated small molecules, and favoring reaction with the methylidene ligand over the phoshinidene ligand. ■ RESULTS AND DISCUSSION A salt elimination reaction of scandium methyl chloride [LSc(Me)Cl] (L = [MeC(NDIPP)CHC(NDIPP)Me] − , DIPP = 2,6-(i Pr) 2 C 6 H 3) 10 with 1 equiv of K[P(H)DIPP] in toluene at room temperature yielded a scandium methyl phosphide [LSc(Me){P(H)DIPP}] (1) in 85% yield. Complex 1 was
Published: 2015
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281. Grafting of lanthanide complexes on silica surfaces dehydroxylated at 200 °C: a theoretical investigation

Author: Laurent Maron, Iann C. Gerber, Romuald Poteau, and Iker del Rosal
Subjects: Lanthanide, Chemistry, Chemical shift, Inorganic chemistry, chemistry.chemical_element, General Chemistry, Grafting, Catalysis, chemistry.chemical_compound, Materials Chemistry, Lanthanum, Cluster (physics), Physical chemistry, Homoleptic, Vicinal
Abstract: Cluster models of SiO2-200 are proposed and compared with spectroscopic (IR and NMR) experimental data. Five models describing the variety of surface silanols (isolated, vicinal and germinal) at the SiO2-200 surface have then been derived and used to study the grafting reaction of homoleptic silylamide lanthanum(III) complexes. Three different grafting modes have been obtained (mono-, bi- and tri-grafted) in line with the experimental knowledge. In terms of energetic stability as well as spectroscopic properties of coordinated OPPh3 (as a probe), all modes could coexist at the surface. The analysis of the δ(31P) chemical shifts for the coordinated OPPh3 indicates some possible important differences in Lewis acidity of the lanthanide centre, which may impact the catalysis.
Published: 2015
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282. Metallacyclic yttrium alkyl and hydrido complexes: synthesis, structures and catalytic activity in intermolecular olefin hydrophosphination and hydroamination

Author: Iker del Rosal, Georgy K. Fukin, A. A. Kissel, Tatyana V. Mahrova, Laurent Maron, Alexander A. Trifonov, Dmitry M. Lyubov, and Anton V. Cherkasov
Subjects: chemistry.chemical_classification, Double bond, 010405 organic chemistry, Stereochemistry, Hydride, Ligand, Ionic bonding, Methoxide, 010402 general chemistry, 01 natural sciences, Medicinal chemistry, Pyrrolidine, 0104 chemical sciences, Inorganic Chemistry, chemistry.chemical_compound, chemistry, Hydroamination, Bond cleavage
Abstract: Metallacyclic neutral and ionic yttrium alkyl complexes coordinated by a dianionic ene-diamido ligand ([2,6-iPr2C6H3NC(Me)=C(Me)NC6H3iPr2-2,6] = L(1)) [L(1)]Y(CH2SiMe3)(THF)2 (2), {[L(1)]Y(CH2SiMe3)2}(-){Li(THF)4}(+) (3), [L(1)]Y(OEt2)(μ-Me)2Li(TMEDA) (4) were synthesized using a salt-metathesis approach starting from the related chloro complex [L(1)]Y(THF)2(μ-Cl)2Li(THF)2 (1) in 70, 85 and 72% yields respectively. The reactions of 2 with H2 or PhSiH3 afford the dimeric hydride {[L(1)]Y(THF)(μ-H)}2(μ-THF) (5) containing two μ-bridging hydrido and one μ-bridging THF ligands (91 and 85% yields). The X-ray studies of complexes 2, 3 and 5 revealed η(2)-coordination of the C=C fragment of an ene-diamido ligand to a Y cation. DFT calculations were carried out to give an insight into the metal-ligand bonding and especially the interaction between the metal and the ene-diamido ligand. The observed bonding of the ene-diamido fragment is found to reflect the acidity of the metal center in the complex that is partially overcome by a better donation from the double bond (better overlap with an empty d orbital at the yttrium center). The treatment of complex 4 with DME resulted in the C-O bond cleavage of DME and afforded a three nuclear methoxide oxide complex [{[L(1)]Y}3(μ(2)-OMe)3(μ(3)-O)](2-)[Li(DME)3](+)2 (6). Complexes 2, 3, 5 and 7 proved to be efficient precatalysts for the intermolecular hydrophosphination of styrene, 4-vinylpyridine, and 1-nonene with PhPH2 and Ph2PH as well as hydroamination of styrene and pyrrolidine.
Published: 2015
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283. Can a pentamethylcyclopentadienyl ligand act as a proton-relay in f-element chemistry? Insights from a joint experimental/theoretical study

Author: Carol J. Burns, Christos E. Kefalidis, Richard A. Andersen, Laurent Maron, David J. Berg, Lionel Perrin, 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)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), 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), Los Alamos National Laboratory (LANL), University of Victoria [Canada] (UVIC), Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Lyon-Université de Lyon-École Supérieure de Chimie Physique Électronique de Lyon (CPE)-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)-Centre National de la Recherche Scientifique (CNRS), University of California [Berkeley] (UC Berkeley), and University of California (UC)-University of California (UC)
Subjects: chemistry.chemical_classification, Coordination sphere, [CHIM.ORGA]Chemical Sciences/Organic chemistry, Ligand, Protonation, Cyclopentanes, Ligands, Photochemistry, Coordination complex, Inorganic Chemistry, Crystallography, chemistry.chemical_compound, Deprotonation, chemistry, Phenylacetylene, Phenylphosphine, Organometallic Compounds, Quantum Theory, Thermodynamics, Reactivity (chemistry), [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Protons
Abstract: Isomerisation of buta-1,2-diene to but-2-yne by (Me(5)C(5))(2)Yb is a thermodynamically favourable reaction, with the Δ(r)G° estimated from experimental data at 298 K to be -3.0 kcal mol(-1). It proceeds in hydrocarbon solvents with a pseudo first-order rate constant of 6.4 × 10(-6) s(-1) and 7.4 × 10(-5) s(-1) in C(6)D(12) and C(6)D(6), respectively, at 20 °C. This 1,3-hydrogen shift is formally forbidden by symmetry and has to occur by an alternative pathway. The proposed mechanism for buta-1,2-diene to but-2-yne isomerisation by (Me(5)C(5))(2)Yb involves coordination of methylallene (buta-1,2-diene) to (Me(5)C(5))(2)Yb, and deprotonation of methylallene by one of the Me(5)C(5) ligands followed by protonation of the terminal methylallenyl carbon to yield the known coordination compound (Me(5)C(5))(2)Yb(η(2)-MeC[triple bond, length as m-dash]CMe). Computationally, this mechanism is not initiated by a single electron transfer step, and the ytterbium retains its oxidation state (II) throughout the reactivity. Experimentally, the influence of the metal centre is discussed by comparison with the reaction of (Me(5)C(5))(2)Ca towards buta-1,2-diene, and (Me(5)C(5))(2)Yb with ethylene. The mechanism by which the Me(5)C(5) acts as a proton-relay within the coordination sphere of a metal also rationalises the reactivity of (i) (Me(5)C(5))(2)Eu(OEt(2)) with phenylacetylene, (ii) (Me(5)C(5))(2)Yb(OEt(2)) with phenylphosphine and (iii) (Me(5)C(5))(2)U(NPh)(2) with H(2) to yield (Me(5)C(5))(2)U(HNPh)(2). In the latter case, the computed mechanism is the heterolytic activation of H(2) by (Me(5)C(5))(2)U(NPh)(2) to yield (Me(5)C(5))(2)U(H)(HNPh)(NPh), followed by a hydrogen transfer from uranium back to the imido nitrogen atom using one Me(5)C(5) ligand as a proton-relay. The overall mechanism by which hydrogen shifts using a pentamethylcyclopentadienyl ligand as a proton-relay is named Carambole in reference to carom billiards.
Published: 2015
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284. Unprecedented Reaction Mode of Phosphorus in Phosphinidene Rare-Earth Complexes: A Joint Experimental-Theoretical Study

Author: Haiwen Tian, Iker del Rosal, Kai Wang, Jianquan Hong, Laurent Maron, Xigeng Zhou, Lixin Zhang, Fudan University [Shanghai], Fudan Univ, Dept Mat Sci, Shanghai 200433, Peoples R China, 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), 973 program [2015CB856600], HPCs CALcul en Midi-Pyrenees (CALMIP-EOS grant) [1415], and National Natural Science Foundation of China [21672038, 21372047, 21732007]
Subjects: 010405 organic chemistry, Chemistry, Ligand, Isocyanide, General Chemistry, 010402 general chemistry, 01 natural sciences, Biochemistry, Medicinal chemistry, Catalysis, 0104 chemical sciences, Metal, chemistry.chemical_compound, Colloid and Surface Chemistry, Phenylacetylene, Phosphinidene, visual_art, visual_art.visual_art_medium, Density functional theory, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Bond cleavage, Carbodiimide
Abstract: International audience; Reactions of trinuclear rare-earth metal complexes bearing functionalized phosphinidene ligand [L(3)Ln(3)(mu(2)-Me)(2)(mu(3)-Me) (mu(3)-eta(1): eta(2):eta(2)-PC6H4-o) (L = [PhC((NC6H4Pr2)-Pr-i-2,6)(2)](-), Ln = Y (la), Lu (lb)) with phenylacetylene, CO2, diisopropyl carbodiimide, isocya-nide, or PhSSPh lead to the formation of a series of phosphorus-containing products. The reaction of 1 with CS2 yields two novel P-methyl-phosphindole-2,3-dithio-late dianion complexes, revealing an unusual tandem desulfurization/coupling/cyclization reaction mode of CS2. A possible reaction pathway was determined by density functional theory calculations. This emphasizes the key role of the reduction power of the formal P2- part of the phosphinidene in the C-S bond cleavage.
Published: 2017
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285. Oxygen Atom Transfer to Cationic PCPNi(II) Complexes Using Amine-N-Oxides

Author: Warren E. Piers, Etienne A. LaPierre, Laurent Maron, Marissa L. Clapson, Denis M. Spasyuk, Chris Gendy, University of Calgary, 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), Canadian Light Source Inc., University of Saskatchewan [Saskatoon] (U of S), NSERC of Canada (Discovery Grant) the Canada Research Chair secretariat (Tier I CRC), Alexander von Humboldt Foundation, Chinese Academy of Science, and CNRS through the PICS program
Subjects: 010405 organic chemistry, Ligand, Aryl, 010402 general chemistry, 01 natural sciences, Medicinal chemistry, 0104 chemical sciences, Pincer movement, Inorganic Chemistry, chemistry.chemical_compound, chemistry, Bromide, Lewis acids and bases, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Physical and Theoretical Chemistry, Pincer ligand, Trifluoromethanesulfonate, Phosphine
Abstract: International audience; Three PCsp3P pincer ligands differing in the aryl group linking the phosphine arms with the anchoring carbon donor were used to support square planar Ni(II) bromide complexes 1-3(Br) Exchange of the coordinating bromide anion for the more wealdy coordinating triflate (OTf) or hexafluoroantimonate (SbF6) anions was accomplished by treatment with AgX or TIX salts to give compounds 1-3(x); compounds 1(OTf) 1(sbF6), 2(Br), 2(OTf), 3(Br) and 3(sbF6) were all characterized by X-ray crystallography. The reactions of these Ni(II) compounds with the amine-N-oxide oxygen atom transfer agents ONMe3 and ONMePh2 were explored. For ONMe3, reactions with 2 equiv gave products in which one arm of the pincer ligand was oxidized to a P=0 unit, with the other amine-N-oxide ligated to the Ni(II) center, forming products 5-6(x); compounds 4(OTf), 5(OTf), and 6(sbF6) were characterized crystallographically. Transient amine-N-oxide adducts prior to ligand oxidation were observed in some reactions. For the more effective 0 atom donor ONMePh2, reactions were very rapid and a second oxidation of the remaining phosphine arm was observed, producing a Ni(II) species with an OCO pincer ligand (7(sbF6)). All compounds were fully characterized. Experiments aimed at trapping transient Ni(IV) oxo intermediates (with cyclohexadiene, KH, and various Lewis acids) indicated that such species were not involved in the reaction. This was supported by density functional theory (DFT) computations at the B3PW91 level, which indicated that direct 0 atom insertion into the Ni-P bonds without the intermediacy of a Ni oxo species was the low-energy pathway.
Published: 2017
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286. Reversible Insertion of a C═C Bond into Magnesium(I) Dimers: Generation of Highly Active 1,2-Dimagnesioethane Compounds

Author: Cameron Jones, Carlos Alvarez Lamsfus, Ashlea Carroll, Aaron J. Boutland, Laurent Maron, Andreas Stasch, Monash University [Melbourne], 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 St Andrews [Scotland], Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and University of St Andrews. School of Chemistry
Subjects: [PHYS]Physics [physics], Ethylene, 010405 organic chemistry, Chemistry, Magnesium, chemistry.chemical_element, DAS, General Chemistry, QD Chemistry, 010402 general chemistry, 01 natural sciences, Biochemistry, Redox, Catalysis, 0104 chemical sciences, Metal, chemistry.chemical_compound, Colloid and Surface Chemistry, visual_art, Polymer chemistry, visual_art.visual_art_medium, [CHIM]Chemical Sciences, QD, Reactivity (chemistry)
Abstract: bibtex: ISI:000418783600015 bibtex\location:'1155 16TH ST, NW, WASHINGTON, DC 20036 USA',publisher:'AMER CHEMICAL SOC',type:'Article',affiliation:'Jones, C (Reprint Author), Monash Univ, Sch Chem, POB 23, Melbourne, Vic 3800, Australia. Maron, L (Reprint Author), Univ Toulouse, 135 Ave Rangueil, F-31077 Toulouse, France. Maron, L (Reprint Author), UPS, INSA, CNRS, LPCNO,UMR 5215, 135 Ave Rangueil, F-31077 Toulouse, France. Boutland, Aaron J.; Carroll, Ashlea; Stasch, Andreas; Jones, Cameron, Monash Univ, Sch Chem, POB 23, Melbourne, Vic 3800, Australia. Lamsfus, Carlos Alvarez; Maron, Laurent, Univ Toulouse, 135 Ave Rangueil, F-31077 Toulouse, France. Lamsfus, Carlos Alvarez; Maron, Laurent, UPS, INSA, CNRS, LPCNO,UMR 5215, 135 Ave Rangueil, F-31077 Toulouse, France. Stasch, Andreas, Univ St Andrews, EaStCHEM Sch Chem, St Andrews KY16 9ST, Fife, Scotland.','author-email':'laurent.maron@irsamc.ups-tlse.fr cameron.jones@monash.edu',da:'2018-12-05','doc-delivery-number':'FR0WB','funding-acknowledgement':'Australian Research Council; Chinese Academy of Science; U.S. Air Force Asian Office of Aerospace Research and Development [FA2386-14-1-4043]; Alexander von Humboldt Foundation','funding-text':'Financial support from the Australian Research Council (C.J.), the U.S. Air Force Asian Office of Aerospace Research and Development (grant FA2386-14-1-4043 to C.J.), The Alexander von Humboldt Foundation (L.M.), and the Chinese Academy of Science (L.M.) is acknowledged.','journal-iso':'J. Am. Chem. Soc.','keywords-plus':'MAIN-GROUP ELEMENTS; AMBIENT CONDITIONS; ETHYLENE; COMPLEXES; CYCLOADDITION; REACTIVITY; ACTIVATION; MOLECULES; CATALYSIS; SILYLENE','number-of-cited-references':'33','orcid-numbers':'Stasch, Andreas/0000-0002-7407-8287','research-areas':'Chemistry','times-cited':'5','unique-id':'ISI:000418783600015','usage-count-last-180-days':'8','usage-count-since-2013':'26','web-of-science-categories':'Chemistry, Multidisciplinary'\; International audience; The insertion of 1,1-diphenylethylene into the Mg-Mg bond of two magnesium(I) dimers, [((Ar)Nacnac)Mg-](2) (Ar = C6H2Me3-2,4,6 (Mes); C6H3Et2-2,6 (Dep)), yielding 1,2-dimagnesioethane products, [\((Ar)Nacnac)Mg\(2)(mu-CH2CPh2)], is described. These reactions are readily reversible at room temperature and thus represent the first examples of room-temperature reversible redox processes for s-block metal complexes. The 1,2-dimagnesioethane products are highly activated magnesium alkyls and Show unprecedented, uncatalyted reactivity toward H-2, CO, and ethylene. Computational studies have investigated the mechanisms of all presented reaction types.
Published: 2017
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287. Silica-Grafted Lanthanum Benzyl Species: Synthesis, Characterization, and Catalytic Applications

Author: Iker del Rosal, Philippe Zinck, Régis M. Gauvin, Laurent Maron, Andreia Valente, Thomas Chenal, Sjoerd Harder, Mostafa Taoufik, Tom Vancompernolle, Unité de Catalyse et Chimie du Solide - UMR 8181 (UCCS), Université d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-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), 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 Électronique de Lyon (CPE)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Inorganic and Organometallic Chemistry, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Centrale Lille Institut (CLIL)-Université d'Artois (UA)-Centrale Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Lille, 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), 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), 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), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie de Toulouse (ICT-FR 2599), 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), ENSCL, CNRS, Centrale Lille, Univ. Artois, Université de Lille, and Unité de Catalyse et Chimie du Solide - UMR 8181 [UCCS]
Subjects: chemistry.chemical_classification, Ethylene, 010405 organic chemistry, Organic Chemistry, Alkyne, chemistry.chemical_element, Nuclear magnetic resonance spectroscopy, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, Photochemistry, 01 natural sciences, 0104 chemical sciences, Styrene, Catalysis, Inorganic Chemistry, chemistry.chemical_compound, [CHIM.POLY]Chemical Sciences/Polymers, chemistry, Polymer chemistry, Benzyl group, Lanthanum, Physical and Theoretical Chemistry, Alkyl, ComputingMilieux_MISCELLANEOUS
Abstract: The grafting of a lanthanum trisbenzyl derivative onto dehydroxylated silica affords a mixture of [(≡SiO)2La(CH2Ph)(THF)n] and [(≡SiO)La(CH2Ph)2(THF)m] surface sites, in respective proportions of 80 and 20%, as evidenced from mass balance analyses, IR and 1H, 13C and 29Si 1D and 2D solid-state NMR spectroscopy. Significant transfer of alkyl groups from lanthanum to the surface was demonstrated. The grafting mechanism was also probed by DFT calculations, which confirm that benzyl group transfer from the lanthanum to the surface (via Si–O–Si cleavage) occurs readily. This material proved to be active in alkyne dimerization and in ethylene, styrene, and e-caprolactone homopolymerization.
Published: 2017
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288. Substitution Effects in Highly Syndioselective Styrene Polymerization Catalysts Based on Single-Component Allyl ansa-Lanthanidocenes: An Experimental and Theoretical Study

Author: Eva Laur, Jean-Michel Brusson, Laurent Maron, Olivier Miserque, Aurélien Vantomme, Jean-François Carpentier, Alexandre Welle, Vincent Dorcet, Evgueni Kirillov, Elisa Louyriac, 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), 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), Total Petrochemicals Research Feluy, Total Petrochemicals, Laboratoire de Chimie des Matériaux Inorganiques (LCMI), Facultés Universitaires Notre Dame de la Paix (FUNDP), TOTAL France S.A., Total S. A., Total Research and Technology Feluy, Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-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)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), 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), 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), 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), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie de Toulouse (ICT-FR 2599), 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), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Polymers and Plastics, 010405 organic chemistry, Single component, Organic Chemistry, Nuclear magnetic resonance spectroscopy, 010402 general chemistry, 01 natural sciences, Medicinal chemistry, 0104 chemical sciences, Catalysis, Styrene, Inorganic Chemistry, chemistry.chemical_compound, chemistry, Polymerization, Tacticity, Polymer chemistry, Materials Chemistry, [CHIM]Chemical Sciences, Polystyrene, Polymerization catalysts
Abstract: International audience; A series of allyl ansa-lanthanidocenes, [{Me2C(C5H4)-(Flu)}Nd(1,3-C3H3(SiMe3)(2))(2)]K (Flu = 9-fluorenyl; 1-Nd-K(allyl)) and {R2C(C5H4)(R'R'Flu)}Ln(1,3-C3H3(SiMe3)(2))(THF)(x) (R = Me, R' = 2,7-tBu(2), Ln = Y (2-Y), Sc (2-Sc), x = 0; Ln = La (2-La), Pr (2-Pr), Nd (2-Nd), Sm (2-Sm), x = 1; R = Me, R' = oct = octamethyloctahydrodibenzo, Ln = Nd, x = 1 (3-Nd); R = Ph, R' = H, Ln = Nd, x = 1 (4-Nd); R = Me, R' = 3,6-tBu(2), Ln = Nd, x = 1 (5-Nd)), were prepared in good yields and characterized by NMR spectroscopy (for diamagnetic complexes 2-Sc, 2-Y, and 2-La) and by single-crystal X-ray diffraction (1-Nd-K(allyl), 2-La, 2-Pr, 2-Nd, 2-Sm, and 4-Nd). Those complexes, especially 1-Nd-K(allyl), 2-Nd, 4-Nd, 2-La, and 2-Sm, act as single-component catalyst precursors for polymerization of styrene (in bulk or in aliphatic hydrocarbon solutions, (nBu)(2)Mg as scavenger, T-polym = 60-140 C), affording highly syndiotactic polystyrene (sPS) ([r](5) = 63-88%; T-m up to 260 C). High productivities (up to 4560 kg(sPS) mol(Ln)(-1) h(-1)) were achieved at 120-140 C, at low catalyst loadings ([St]/[Nd] = 20000-76000 equiv), with 2-Nd and 2-Pr. On the other hand, precursors having bulky substituents on the fluorenyl moieties in 3,6-positions (3-Nd, 5-Nd) or based on small ionic radius metals (2-Y, 2-Sc) were poorly or not active under standard polymerization conditions. These results have been rationalized by DFT computations, which included the solvent, carried out on the putative 1-Nd, and the isolated 2-Nd and 5-Nd complexes. Three consecutive styrene insertions were studied, and it was revealed that (i) the formation of sPS is thermodynamically controlled by two effects-minimization of repulsions between fluorenyl/styrene phenyl ring and (in the initiation phase) fluorenyl/SiMe3 substituents of the allyl ligand-and (ii) the presence of bulky substituents on the fluorenyl moiety does not influence the activation barrier of monomer insertion, but it may destabilize thermodynamically the insertion product.
Published: 2017
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289. Synthesis and Reactivity of a Scandium Terminal Hydride: H

Author: Xianghao, Han, Li, Xiang, Carlos A, Lamsfus, Weiqing, Mao, Erli, Lu, Laurent, Maron, Xuebing, Leng, and Yaofeng, Chen
Abstract: Dihydrogen is easily activated by a scandium terminal imido complex containing the weakly coordinated THF. The reaction proceeds through a 1,2-addition mechanism, which is distinct from the σ-bond metathesis mechanism reported to date for rare-earth metal-mediated H
Published: 2017

290. Electronic Structure and Properties of Berkelium Iodates

Author: Teresa M. Eaton, Gustavo E. Scuseria, Cristian Celis-Barros, Gregory A. Galmin, Paul Kögerler, Ronald J. Clark, Alexandra A. Arico, Matthew L. Marsh, Lambertus J. van de Burgt, Kevin Seidler, Manfred Speldrich, Kuan-Wen Chen, Frédéric Gendron, Alejandro J. Garza, Alexander T. Chemey, David E. Hobart, Ramiro Arratia-Pérez, Shane S. Galley, Ashley L. Gray, Jason A. Johnson, Jochen Autschbach, Laurent Maron, Ryan Baumbach, Dayán Páez-Hernández, Jamie C. Wang, Mark A. Silver, Kenneth Hanson, Thomas E. Albrecht-Schmitt, Shelley M. Van Cleve, Michael Ruf, Samantha K. Cary, Florida State University [Tallahassee] (FSU), Department of Chemistry and Biochemistry, Tallahassee (DCB), National High Magnetic Field Laboratory (NHMFL), FSU, Department of Chemistry and Biochemistry, and National High Magnetic Field Laboratory, Environmental Health and Safety, Nuclear Materials Processing Group [Oak Ridge], Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC-UT-Battelle, LLC, Department of Chemistry [Buffalo], University at Buffalo [SUNY] (SUNY Buffalo), State University of New York (SUNY)-State University of New York (SUNY), Department of Chemistry [Houston], Rice University [Houston], 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), Institut für Anorganische Chemie, Rheinisch-Westfälische Technische Hochschule Aachen (RWTH), Centro de NanoCiencias Aplicadas [Santiago] (CANS), Universidad Andrés Bello [Santiago] (UNAB), Bruker AXS, Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and Rheinisch-Westfälische Technische Hochschule Aachen University (RWTH)
Subjects: Lanthanide, [PHYS]Physics [physics], Ionic radius, Photoluminescence, Absorption spectroscopy, 010405 organic chemistry, Inorganic chemistry, General Chemistry, 010402 general chemistry, 01 natural sciences, Biochemistry, Catalysis, 0104 chemical sciences, 3. Good health, Bond length, Crystallography, chemistry.chemical_compound, Colloid and Surface Chemistry, chemistry, ddc:540, [CHIM]Chemical Sciences, Absorption (chemistry), Luminescence, Iodate
Abstract: bibtex: ISI:000412043000020 bibtex\location:'1155 16TH ST, NW, WASHINGTON, DC 20036 USA',publisher:'AMER CHEMICAL SOC',type:'Article',affiliation:'Albrecht-Schmitt, TE (Reprint Author), Florida State Univ, Dept Chem & Biochem, Tallahassee, FL 32306 USA. Silver, Mark A.; Cary, Samantha K.; Arico, Alexandra A.; Galmin, Gregory A.; Wang, Jamie C.; Clark, Ronald J.; Chemey, Alexander; Eaton, Teresa M.; Marsh, Matthew L.; Seidler, Kevin; Galley, Shane S.; van de Burgt, Lambertus; Hobart, David E.; Hanson, Kenneth; Albrecht-Schmitt, Thomas E., Florida State Univ, Dept Chem & Biochem, Tallahassee, FL 32306 USA. Garza, Alejandro J.; Scuseria, Gustavo E., Rice Univ, Dept Chem, POB 1892, Houston, TX 77251 USA. Baumbach, Ryan E.; Chen, Kuan-Wen, Natl High Magnet Field Lab, Tallahassee, FL 32310 USA. Johnson, Jason A.; Gray, Ashley L., Florida State Univ, Environm Hlth & Safety, Tallahassee, FL 32306 USA. Van Cleve, Shelley M., Oak Ridge Natl Lab, Nucl Mat Proc Grp, One Bethel Valley Rd, Oak Ridge, TN 37830 USA. Gendron, Frederic; Autschbach, Jochen, Univ Buffalo State Univ New York, Dept Chem, Buffalo, NY 14260 USA. Maron, Laurent, Inst Natl Sci Appl, Lab Phys & Chim Nanoobjets, F-31077 Toulouse 4, France. Speldrich, Manfred; Koegerler, Paul, Rhein Westfal TH Aachen, Inst Anorgan Chem, D-52074 Aachen, Germany. Celis-Barros, Cristian; Paez-Hernandez, Dayan; Arratia-Perez, Ramiro, Univ Andres Bello, Fac Ciencias Exactas, Ctr Nanociencias Aplicadas, Republ 275, Santiago, Chile. Ruf, Michael, Bruker AXS, 5465 East Cheryl Pkwy, Madison, WI 53711 USA.','author-email':'albrecht-schinitt@chem.fsu.edu',da:'2018-12-05','doc-delivery-number':'FI5SB','funding-acknowledgement':'U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Heavy Elements Chemistry Program [DE-FG02-13ER16414, DE-SC0001136, DE-FG02-04ER15523]; Welch Foundation Chair [C-0036]; National Science Foundation [DMR-1157490, DGE-1449440]; State of Florida; U.S. Department of Energy; CBFO Fellowship Program (MAS) - U.S. Department of Energy','funding-text':'This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Heavy Elements Chemistry Program, under Award Numbers DE-FG02-13ER16414 (FSU), DE-SC0001136 (formerly DE-FG02-09ER16066) (FG & JA), and DE-FG02-04ER15523 (G.E.S). G.E.S. is a Welch Foundation Chair (Grant No. C-0036). The isotopes used in this research were supplied by the U.S. Department of Energy, Office of Science, by the Isotope Program in the Office of Nuclear Physics. The \textlessSUP\textgreater249\textless/SUP\textgreaterBk was provided to Florida State University by the Isotope Development and Production for Research and Applications Program through the Radiochemical Engineering and Development Center at Oak Ridge National Laboratory. Magnetization measurements using the VSM SQUID MPMS were performed at the National High Magnetic Field Laboratory, which is supported by National Science Foundation Cooperative Agreement No. DMR-1157490, the State of Florida, and the U.S. Department of Energy. This research is supported in part by an appointment to the CBFO Fellowship Program (MAS), sponsored by the U.S. Department of Energy and administered by the Oak Ridge Institute for Science and Education. Jamie Wang is supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1449440.','journal-iso':'J. Am. Chem. Soc.','keywords-plus':'VALENCE BASIS-SETS; ENERGY-ADJUSTED PSEUDOPOTENTIALS; MOLECULAR-ORBITAL METHODS; CRYSTAL-STRUCTURE; AB-INITIO; MAGNETIC-SUSCEPTIBILITY; COORDINATION GEOMETRY; PERTURBATION-THEORY; IONIC-RADII; PLUTONIUM','number-of-cited-references':'113',oa:'Bronze','orcid-numbers':'Kogerler, Paul/0000-0001-7831-3953 Gendron, Frederic/0000-0002-1896-3978 Hanson, Kenneth/0000-0001-7219-7808 Albrecht-Schmitt, Thomas/0000-0002-2989-3311 Chemey, Alexander/0000-0002-0679-7845 Paez, Dayan/0000-0003-2747-9982 Speldrich, Manfred/0000-0002-8626-6410 Celis-Barros, Cristian/0000-0002-4685-5229 Garza, Alejandro/0000-0001-6995-2833','research-areas':'Chemistry','researcherid-numbers':'Kogerler, Paul/H-5866-2013','times-cited':'5','unique-id':'ISI:000412043000020','usage-count-last-180-days':'8','usage-count-since-2013':'36','web-of-science-categories':'Chemistry, Multidisciplinary'\; International audience; The reaction of Bk-249(OH)(4) with iodate under hydro thermal conditions results in the formation of Bk(IO3)(3) as the major product with trace amounts of Bk(IO3)(4) also crystallizing from the reaction mixture. The structure of Bk(Io(3))(3) consists of nine-coordinate BO cations that are bridged by iodate anions to yield layers that are isomorphous with those found for Am-III, Cf-III, and with lanthanides that possess similar ionic radii. Bk(IO3)(4) was expected to adopt the same structure as M(IO3)(4) (M = Ce, Np, Pu), but instead parallels the structural chemistry of the smaller Zr-IV cation. Bk-III-O and Bk-IV-O bond lengths are shorter than anticipated and provide further support for a postcurium break in the actinide series. Photoluminescence and absorption spectra collected from single crystals of Bk(IO3)(4) show evidence for doping with Bkill in these crystals. In addition to luminescence from Bkul in the Bk(IO3)(4) crystals, a broad-band absorption feature is initially present that is similar to features observed in systems with intervalence charge transfer. However, the high-specific activity of Bk-249 (t(1/2) = 320 d) causes oxidation of Bk-III and only Bk-IV is present after a few days with concomitant loss of both the Bk-III luminescence and the broadband feature. The electronic structure of Bk(IO3)(3) and Bk(IO3)(4) were examined using a range of computational methods that include density functional theory both on clusters and on periodic structures, relativistic ab initio wave function calculations that incorporate spin orbit coupling (CASSCF), and by a full-model Hamiltonian with spin-orbit coupling and Slater-Condon parameters (CONDON). Some of these methods provide evidence for an asymmetric ground state present in Bk-IV that does not strictly adhere to Russel Saunders coupling and Hund's Rule even though it possesses a half-filled Sf(7) shell. Multiple factors contribute. to the asymmetry that include 5f electrons being present in microstates that are not solely spin up, spin-orbit coupling induced mixing of low-lying excited states with the ground state, and covalency in the Bk-IV-O bonds that distributes the 5f electrons onto the ligands. These factors are absent or diminished in other f(7) ions such as Gd-III or Cm-III.
Published: 2017
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291. Frontispiece: Gold(I)-Catalysed Asymmetric Hydroamination of Alkenes: A Silver- and Solvent-Dependent Enantiodivergent Reaction

Author: Xavier Trivelli, Maxence Vandewalle, Christophe Michon, Francine Agbossou-Niedercorn, Bernhard Linden, Pascal Roussel, Nathalie Duhal, Mostafa Kouach, Iker del Rosal, Frédéric Capet, Marc-Antoine Abadie, Laurent Maron, Florian Medina, and Eric Génin
Subjects: Solvent, Chemistry, Organic Chemistry, Organic chemistry, General Chemistry, Hydroamination, Catalysis
Published: 2017
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292. Calcium Hydride Cation [CaH]

Author: Danny, Schuhknecht, Carolin, Lhotzky, Thomas P, Spaniol, Laurent, Maron, and Jun, Okuda
Abstract: Reaction of dibenzyl calcium complex [Ca(Me
Published: 2017

293. Accessing Stable Magnesium Acyl Compounds: Reductive Cleavage of Esters by Magnesium(I) Dimers

Author: Laurent Maron, Andreas Stasch, Brant Maitland, Carlos Alvarez Lamsfus, Aaron J. Boutland, Cameron Jones, Monash University [Melbourne], 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 St Andrews [Scotland], Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and University of St Andrews. School of Chemistry
Subjects: magnesium acyl, chemistry.chemical_element, Ester cleavage, reduction, 010402 general chemistry, 01 natural sciences, Catalysis, Umpolung, Organic chemistry, [CHIM]Chemical Sciences, QD, magnesium(I), Reduction, [PHYS]Physics [physics], ester cleavage, 010405 organic chemistry, Magnesium, Organic Chemistry, Magnesium(I), DAS, General Chemistry, QD Chemistry, umpolung, Magnesium acyl, 0104 chemical sciences, chemistry, Research council, Reductive cleavage
Abstract: bibtex: ISI:000412595600030 bibtex\location:'POSTFACH 101161, 69451 WEINHEIM, GERMANY',publisher:'WILEY-V C H VERLAG GMBH',type:'Article',affiliation:'Stasch, A; Jones, C (Reprint Author), Monash Univ, Monash Ctr Catalysis, Sch Chem, POB 23, Melbourne, Vic 3800, Australia. Maron, L (Reprint Author), Univ Toulouse, 135 Ave Rangueil, F-31077 Toulouse, France. Maron, L (Reprint Author), UPS, CNRS, INSA, UMR 5215,LPCNO, 135 Ave Rangueil, F-31077 Toulouse, France. Stasch, A (Reprint Author), Univ St Andrews, EaStCHEM Sch Chem, St Andrews KY16 9ST, Fife, Scotland. Boutland, Aaron J.; Maitland, Brant; Stasch, Andreas; Jones, Cameron, Monash Univ, Monash Ctr Catalysis, Sch Chem, POB 23, Melbourne, Vic 3800, Australia. Lamsfus, Carlos A.; Maron, Laurent, Univ Toulouse, 135 Ave Rangueil, F-31077 Toulouse, France. Lamsfus, Carlos A.; Maron, Laurent, UPS, CNRS, INSA, UMR 5215,LPCNO, 135 Ave Rangueil, F-31077 Toulouse, France. Stasch, Andreas, Univ St Andrews, EaStCHEM Sch Chem, St Andrews KY16 9ST, Fife, Scotland.','author-email':'laurent.maron@irsamc.ups-tlse.fr as411@st-andrews.ac.uk cameron.jones@monash.edu',da:'2018-12-05','doc-delivery-number':'FJ2XV',eissn:'1521-3765','funding-acknowledgement':'Australian Research Council; U.S. Air Force Asian Office of Aerospace Research and Development [FA2386-14-1-4043]','funding-text':'C.J. and A.S. thank the Australian Research Council for financial support. C.J. also thanks the U.S. Air Force Asian Office of Aerospace Research and Development (grant FA2386-14-1-4043). Part of this research was undertaken on the MX1 beamline at the Australian Synchrotron, Victoria, Australia.','journal-iso':'Chem.-Eur. J.','keywords-plus':'CARBON-MONOXIDE; CO; ACTIVATION; COMPLEXES; ISONITRILES; REACTIVITY; CHEMISTRY; INSERTION; HYDRIDE; LIGAND','number-of-cited-references':'33',oa:'Bronze','orcid-numbers':'Alvarez Lamsfus, Carlos/0000-0002-4442-7052','research-areas':'Chemistry','times-cited':'0','unique-id':'ISI:000412595600030','usage-count-last-180-days':'3','usage-count-since-2013':'17','web-of-science-categories':'Chemistry, Multidisciplinary'\; International audience; The first examples of magnesium acyls, [(Nacnac)Mg\mu-C(Ph)O\(mu-OR)Mg(Nacnac)] (R=Me, tBu or Ph; Nacnac=[HC(MeCNAr)(2)](-); Ar=C6H2Me3-2,4,6 ((Mes)Nacnac), C6H3Et2-2,6 ((Dep)Nacnac), C(6)H(3)iPr(2)-2,6 ((Dip)Nacnac)), have been prepared by reductive cleavage of a series of esters using dimeric magnesium(I) reducing agents, [\(Nacnac)Mg\(2)]. Crystallographic studies reveal the complexes to be dimeric, being bridged by both phenyl-acyl and alkoxide/aryloxide fragments. The crystal structures, combined with results of spectroscopic and computational studies suggest that the nature of the acyl ligands within these complexes should be viewed as lying somewhere between anionic umpolung acyl and oxo-carbene. However, reactions of the acyl complexes with a variety of organic electrophiles did not provide evidence of umpolung acyl reactivity. A number of attempts to prepare alkoxide free magnesium acyls were carried out, and while these were unsuccessful, they did lead to unusual products, the crystallographic and spectroscopic details of which are discussed.
Published: 2017
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294. SO

Author: Elisa, Louyriac, Peter W, Roesky, and Laurent, Maron
Abstract: Recently, it was shown that samarocene oxide [Cp*
Published: 2017

295. Hydrodeoxygenation of isocyanates : snapshots of a magnesium-mediated C=O bond cleavage

Author: Catherine Weetman, Jian Fang, Yan-Yan Yang, Mary F. Mahon, Michael S. Hill, Mathew D. Anker, Laurent Maron, Lanzhou University, University of Bath [Bath], 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, University of Bath, Claverton Down, Bath BA2 7AY, UK, 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: [PHYS]Physics [physics], 010405 organic chemistry, Magnesium, chemistry.chemical_element, General Chemistry, 010402 general chemistry, 01 natural sciences, Medicinal chemistry, 0104 chemical sciences, Catalysis, Hydroboration, chemistry.chemical_compound, chemistry, Amide, Hemiaminal, Organic chemistry, [CHIM]Chemical Sciences, QD, Hydrodeoxygenation, Deoxygenation, Bond cleavage
Abstract: bibtex: ISI:000400553000027 bibtex\location:'THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND',publisher:'ROYAL SOC CHEMISTRY',type:'Article',affiliation:'Fang, J (Reprint Author), Lanzhou Univ, Sch Chem & Chem Engn, Key Lab Nonferrous Met Chem & Resources Utilizat, Lanzhou 730000, Peoples R China. Hill, MS (Reprint Author), Univ Bath, Dept Chem, Bath BA2 7AY, Avon, England. Yang, Yan; Fang, Jian, Lanzhou Univ, Sch Chem & Chem Engn, Key Lab Nonferrous Met Chem & Resources Utilizat, Lanzhou 730000, Peoples R China. Anker, Mathew D.; Mahon, Mary F.; Weetman, Catherine; Hill, Michael S., Univ Bath, Dept Chem, Bath BA2 7AY, Avon, England. Maron, Laurent, Univ Toulouse, LPCNO, INSA Toulouse, 135,Ave Rangueil, F-31077 Toulouse, France.','author-email':'fangj@lzu.edu.cn msh27@bath.ac.uK',da:'2018-12-05','doc-delivery-number':'ET8MH',eissn:'2041-6539','funding-acknowledgement':'EPSRC (UK); University of Bath','funding-text':'We thank the EPSRC (UK) and the University of Bath for funding of studentships for CW and MDA.','journal-iso':'Chem. Sci.','keywords-plus':'ALKALINE-EARTH CATALYSIS; SELECTIVE REDUCTION; SECONDARY AMIDES; HYDROBORATION; AMINES; CARBONYL; DERIVATIVES; TERTIARY; CARBOXAMIDES; CHEMICALS','number-of-cited-references':'51',oa:'DOAJ Gold','orcid-numbers':'Weetman, Catherine/0000-0001-5643-9256 Anker, Mathew/0000-0003-0414-7635 Hill, Michael/0000-0001-9784-9649','research-areas':'Chemistry','researcherid-numbers':'Weetman, Catherine/O-3395-2018','times-cited':'4','unique-id':'ISI:000400553000027','usage-count-last-180-days':'6','usage-count-since-2013':'39','web-of-science-categories':'Chemistry, Multidisciplinary'\; International audience; Organic isocyanates are readily converted to methyl amine products through their hydroboration with HBpin in the presence of a beta-diketiminato magnesium catalyst. Although borylated amide and N-,O-bis(boryl)hemiaminal species have been identified as intermediates during the reductive catalysis, the overall reduction and C-O activation is metal-mediated and proposed to occur through the further intermediacy of well-defined magnesium formamidato, formamidatoborate and magnesium boryloxide derivatives. Examples of all these species have been identified and fully characterised through stoichiometric reactivity studies and the stability of the borate species leads us to suggest that, under catalytic conditions, the onward progress of the deoxygenation reaction is crucially dependent on the further activation provided by the Lewis acidic HBpin substrate. These deductions have been explored and ratified through a DFT study.
Published: 2017
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296. Mechanistic Aspects of the Polymerization of Lactide Using a Highly Efficient Aluminum(III) Catalytic System

Author: Carine Robert, Marie-Noëlle Rager, Sumesh K. Raman, Laurent Maron, Régis M. Gauvin, Iker del Rosal, Vincent Guérineau, Vincent Richard, Thibault E. Schmid, Christophe M. Thomas, Xavier Trivelli, Yohann Morin, and Pierre Haquette
Subjects: Lactide, 010405 organic chemistry, Dispersity, General Chemistry, 010402 general chemistry, 01 natural sciences, Biochemistry, Catalysis, 0104 chemical sciences, chemistry.chemical_compound, Colloid and Surface Chemistry, Monomer, chemistry, Polymerization, Salen ligand, Reagent, Alkoxide, Polymer chemistry
Abstract: We report here a unique example of an in situ generated aluminum initiator stabilized by a C2-symmetric salen ligand which shows a hitherto unknown high activity for the ROP of rac-lactide at room temperature. Using a simple and robust catalyst system, which is prepared from a salen complex and an onium salt, this convenient route employs readily available reagents that afford polylactide in good yields with narrow polydispersity indices, without the need for time-consuming and expensive processes that are typically required for catalyst preparation and purification. In line with the experimental evidence, DFT studies reveal that initiation and propagation proceed via an external alkoxide attack on the coordinated monomer.
Published: 2017

297. Reactions of Neutral Cobalt(II) Complexes of a Dianionic Tetrapodal Pentadentate Ligand: Cobalt(III) Amides from Imido Radicals

Author: Laurent Maron, Lucie Nurdin, Denis M. Spasyuk, and Warren E. Piers
Subjects: Steric effects, 010405 organic chemistry, Chemistry, Ligand, Aryl, Coordination number, Radical, 010402 general chemistry, Photochemistry, 01 natural sciences, 0104 chemical sciences, Adduct, Inorganic Chemistry, chemistry.chemical_compound, Polymer chemistry, Reactivity (chemistry), Azide, Physical and Theoretical Chemistry
Abstract: Neutral cobalt(II) complexes of the dianionic tetrapodal pentadentate ligand B2Pz4Py, in which borate linkers supply the anionic charges, are reported. Both the six-coordinate THF adduct 1-THF and the five-coordinate THF-free complex 1 are in a high-spin S = 3/2 configuration in the ground state and have been structurally characterized by X-ray crystallography. These two Co(II) starting materials react rapidly with aryl azides of moderate steric bulk. The thermodynamic products of these reactions are low-spin, diamagnetic, Co(III) amido complexes that are either monomeric, when an external hydrogen atom source such as 1,4-cyclohexadiene is present, or dimeric products formed via C-C coupling of the azide aryl group and internal transfer of H• to the nitrogen. These products are fully characterized and are rare examples of octahedral Co amido compounds; structural determinations reveal significant pyramidalization of the amido nitrogens due to π-π repulsion wherein the amido ligand is primarily a σ donor. The amido products arise from highly reactive Co(III) imido radical intermediates that are the kinetic products of the reactions of 1 or 1-THF with the azide reagents. The imido radicals can be detected by X-band EPR spectroscopy and have been probed by density functional theory computations, which indicate that this doublet species is characterized by a high degree of spin localization on the imido ligand, accounting for the reactivity with hydrogen atom sources and dimerization chemistry observed. The high coordination number and the electron-rich nature of the dianionic B2Pz4Py ligand framework render the imido ligand formed highly reactive.
Published: 2017

298. The role of uranium-arene bonding in H

Author: Dominik P, Halter, Frank W, Heinemann, Laurent, Maron, and Karsten, Meyer
Abstract: The reactivity of uranium compounds towards small molecules typically occurs through stoichiometric rather than catalytic processes. Examples of uranium catalysts reacting with water are particularly scarce, because stable uranyl groups form that preclude the recovery of the uranium compound. Recently, however, an arene-anchored, electron-rich uranium complex has been shown to facilitate the electrocatalytic formation of H
Published: 2017

299. Molecular and Electronic Structures of Eight-Coordinate Uranium Bipyridine Complexes: A Rare Example of a Bipy

Author: Michael W, Rosenzweig, Frank W, Heinemann, Laurent, Maron, and Karsten, Meyer
Abstract: Reaction of trivalent [((
Published: 2017

300. Reactivity studies on [Cp'Fe(μ-I)]

Author: Matthias, Reiners, Miyuki, Maekawa, Constantin G, Daniliuc, Matthias, Freytag, Peter G, Jones, Peter S, White, Johannes, Hohenberger, Jörg, Sutter, Karsten, Meyer, Laurent, Maron, and Marc D, Walter
Subjects: Chemistry
Abstract: Facile pseudohalide activation occurs in the reaction of SCN–, SeCN– and N3– with the iron half-sandwich [Cp′Fe(μ-I)]2., The iron half-sandwich [Cp′Fe(μ-I)]2 (Cp′ = 1,2,4-(Me3C)3C5H2, 1) reacts with the pseudohalides NCO–, SCN–, SeCN– and N3– to give [Cp′Fe(μ-NCO)]2 (2), [Cp′Fe(μ-S)]2 (3), [Cp′Fe(μ-Se2)]2 (4) and [Cp′Fe(μ-N)]2 (5), respectively. Various spectroscopic techniques including X-ray diffraction, solid-state magnetic susceptibility studies and 57Fe Mössbauer spectroscopy were employed in the characterization of these species. Mössbauer spectroscopy shows a decreasing isomer shift with increasing formal oxidation state, ranging from Fe(ii) to Fe(iv), in complexes 1 to 5. The sulfido-bridged dimer 3 exhibits strong antiferromagnetic coupling between the Fe(iii) centers. This leads to temperature-independent paramagnetism (TIP) at low temperature, from which the energy gap between the ground and the excited state can be estimated to be 2J = ca. 700 cm–1. The iron(iv) nitrido complex [Cp′Fe(μ-N)]2 (5) shows no reactivity towards H2 (10 atm), but undergoes clean reactions with CO (5 bar) and XylNC (Xyl = 2,6-Me2C6H3) to form the diamagnetic isocyanate and carbodiimide complexes [Cp′Fe(CO)2(NCO)] (7) and [Cp′Fe(CNXyl)2(NCNXyl)] (8), respectively. All compounds were fully characterized, and density functional theory (DFT) computations provide useful insights into their formation and the electronic structures of complexes 3 and 5.
Published: 2017

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