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2. Variable Ca‐Caryl Hapticity and its Consequences in Arylcalcium Dimers

Author

Kyle G. Pearce, Chiara Dinoi, Ryan J. Schwamm, Laurent Maron, Mary F. Mahon, and Michael S. Hill

Subjects
biaryls, calcium, density functional theory, main group chemistry, Science
Abstract

Abstract The dimeric β‐diketiminato calcium hydride, [(DippBDI)CaH]2 (DippBDI = HC{(Me)CN‐2,6‐i‐Pr2C6H3}2), reacts with ortho‐, meta‐ or para‐tolyl mercuric compounds to afford hydridoarylcalcium compounds, [(DippBDI)2Ca2(μ‐H)(μ‐o‐,m‐,p‐tolyl)], in which dimer propagation occurs either via μ2‐η1‐η1 or μ2‐η1‐η6 bridging between the calcium centers. In each case, the orientation and hapticity of the aryl units is dependent upon the position of the methyl substituent. While wholly organometallic meta‐ and para‐tolyl dimers, [(DippBDI)Ca(m‐tolyl)]2 and [(DippBDI)Ca(p‐tolyl)]2, can be prepared and are stable, the ortho‐tolyl isomer is prone to isomerization to a calcium benzyl analog. Computational analysis of this latter process with density functional theory (DFT) highlights an unusual mechanism invoking the generation of an intermediate dicalcium species in which the group 2 centers are bridged by a toluene dianion formed by the formal attachment of the original hydride anion to the initially generated ortho‐tolyl substituent. Use of a more sterically encumbered aryl substituent, {3,5‐t‐Bu2C6H3}, facilitates the selective formation of [(DippBDI)Ca(μ‐H)(μ‐3,5‐t‐Bu2C6H3)Ca(DippBDI)], which can be converted into the unsymmetrically‐substituted σ‐aryl calcium complexes, [(DippBDI)Ca(μ‐Ph)(μ‐3,5‐t‐Bu2C6H3)Ca(DippBDI)] and [(DippBDI)Ca(μ‐p‐tolyl)(μ‐3,5‐t‐Bu2C6H3)Ca(DippBDI)] by reaction with the appropriate mercuric diaryl. Conversion of [(DippBDI)Ca(H)(Ph)Ca(DippBDI)] to afford [{{(DippBDI)Ca}2(μ2‐Cl)}2(C6H5‐C6H5)], comprising a biphenyl dianion, is also reported. Although this latter transformation is serendipitous, AIM analysis highlights that, in a related manner to the ortho‐tolyl to benzyl isomerization, the requisite C–C coupling may be facilitated in an “across dimer” fashion by the experimentally‐observed polyhapto engagement of the aryl substituents with each calcium.

Published
2023
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3. Photochemical Synthesis of Transition Metal-Stabilized Uranium(VI) Nitride Complexes

Author

Xiaoqing Xin, Iskander Douair, Thayalan Rajeshkumar, Yue Zhao, Shuao Wang, Laurent Maron, and Congqing Zhu

Subjects
Science
Abstract

The synthesis and isolation of uranium(VI) nitride complexes remains challenging. Here, the authors report an example of transition metal (TM) stabilized U(VI) nitride complexes, generated via photolysis of azide-bridged U(IV)-TM precursors.

Published
2022
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4. Evidence for ligand- and solvent-induced disproportionation of uranium(IV)

Author

Jingzhen Du, Iskander Douair, Erli Lu, John A. Seed, Floriana Tuna, Ashley J. Wooles, Laurent Maron, and Stephen T. Liddle

Subjects
Science
Abstract

Disproportion of uranium(IV) is rare, as it is usually the stable product of uranium(III) or (V) disproportionation. Here, the authors report uranium(IV) disproportionation to uranium(III) and (V) revealing ligand and solvent control over a key thermodynamic property of uranium

Published
2021
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5. Hydroarylation of olefins catalysed by a dimeric ytterbium(II) alkyl

Author

Georgia M. Richardson, Iskander Douair, Scott A. Cameron, Joe Bracegirdle, Robert A. Keyzers, Michael S. Hill, Laurent Maron, and Mathew D. Anker

Subjects
Science
Abstract

Nucleophilic alkylation of aromatics with main group reagents was achieved, but it is limited to a stoichiometric regime. Here, the authors report that the ytterbium(II) hydride reacts with ethene and propene to afford ytterbium(II) n-alkyls, both of which can facilitate the catalytic alkylation of benzene at room temperature via an SN2 mechanism.

Published
2021
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6. Synthesis and versatile reactivity of scandium phosphinophosphinidene complexes

Author

Bin Feng, Li Xiang, Karl N. McCabe, Laurent Maron, Xuebing Leng, and Yaofeng Chen

Subjects
Science
Abstract

Rare-earth monometallic phosphinidene complexes have been elusive synthetic targets. Here, the authors describe the synthesis and tunable reactivity of two scandium phosphinophosphinidene complexes containing very unusual Sc-P multiple bonds.

Published
2020
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7. Terminal uranium(V)-nitride hydrogenations involving direct addition or Frustrated Lewis Pair mechanisms

Author

Lucile Chatelain, Elisa Louyriac, Iskander Douair, Erli Lu, Floriana Tuna, Ashley J. Wooles, Benedict M. Gardner, Laurent Maron, and Stephen T. Liddle

Subjects
Science
Abstract

Despite their importance as mechanistic models for Haber Bosch ammonia synthesis from N2 and H2, high oxidation state terminal metal-nitrides are notoriously unreactive towards H2. Here, the authors report hydrogenolysis of a uranium(V)-nitride, which can occur directly or by Frustrated Lewis Pair chemistry with a borane ancillary.

Published
2020
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8. Thorium-nitrogen multiple bonds provide evidence for pushing-from-below for early actinides

Author

Jingzhen Du, Carlos Alvarez-Lamsfus, Elizabeth P. Wildman, Ashley J. Wooles, Laurent Maron, and Stephen T. Liddle

Subjects
Science
Abstract

Despite the burgeoning nature of uranium–ligand multiple bonding, analogous thorium complexes remain incredibly rare. Here the authors report evidence for a transient thorium–nitride species, which, together with data on parent imido derivatives, suggests that the pushing-from-below phenomenon may be more widespread than previously thought.

Published
2019
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12. A versatile strategy for the formation of hydride-bridged actinide–iridium multimetallics

Author

Christopher Z. Ye, Iker Del Rosal, Michael A. Boreen, Erik T. Ouellette, Dominic R. Russo, Laurent Maron, John Arnold, and Clément Camp

Subjects
General Chemistry
Abstract

Uranium- and thorium-iridium multimetallic species with unprecedented actinide–iridium interactions are prepared via salt-elimination reactions between U/Th halides and K[IrCp*H3].

Published
2023
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13. Molybdenum carbonyl assisted reductive tetramerization of CO by activated magnesium(<scp>i</scp>) compounds: squarate dianion vs. metallo-ketene formation

Author

K. Yuvaraj, Jeremy C. Mullins, Thayalan Rajeshkumar, Iskander Douair, Laurent Maron, and Cameron Jones

Subjects
General Chemistry
Abstract

The reductive tetramerisation of CO by Lewis base activated dimagnesium(i) compounds, in the presence of Mo(CO)6, led to the competitive formation of magnesium squarate and metallo-ketene complexes (see picture).

Published
2023
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14. La-Catalyzed Decarbonylation of Formamides and Its Applications

Author

Shaocheng Li, Thayalan Rajeshkumar, Jincheng Liu, Laurent Maron, and Xigeng Zhou

Subjects
Organic Chemistry, Physical and Theoretical Chemistry, Biochemistry
Abstract

Herein we report the first catalytic decarbonylation and decarbonylative hydroamination of formamides without using additives enabled by a redox-neutral rare earth catalyst. The protocol displays complete

Published
2022
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15. Thorium- and Uranium-Mediated C–H Activation of a Silyl-Substituted Cyclobutadienyl Ligand

Author

Nikolaos Tsoureas, Thayalan Rajeshkumar, Oliver P. E. Townrow, Laurent Maron, Richard A. Layfield, University of Sussex, 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)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Chemistry Research Laboratory [Oxford, UK], and University of Oxford

Subjects
Inorganic Chemistry, OXIDATION-STATE, [CHIM]Chemical Sciences, COMPLEXES, Physical and Theoretical Chemistry
Abstract

Cyclobutadienyl complexes of the f-elements are a relatively new yet poorly understood class of sandwich and half-sandwich organometallic compounds. We now describe cyclobutadienyl transfer reactions of the magnesium reagent [(η4-Cb'''')Mg(THF)3] (1), where Cb'''' is tetrakis(trimethylsilyl)cyclobutadienyl, toward thorium(IV) and uranium(IV) tetrachlorides. The 1:1 stoichiometric reactions between 1 and AnCl4 proceed with intact transfer of Cb'''' to give the half-sandwich complexes [(η4-Cb'''')AnCl(μ-Cl)3Mg(THF)3] (An = Th, 2; An = U, 3). Using a 2:1 reaction stoichiometry produces [Mg2Cl3(THF)6][(η4-Cb'''')An(η3-C4H(SiMe3)3-κ-(CH2SiMe2)(Cl)] (An = Th, [Mg2Cl3(THF)6][4]; An = U [Mg2Cl3(THF)6][5]), in which one Cb'''' ligand has undergone cyclometalation of a trimethylsilyl group, resulting in the formation of an An–C σ-bond, protonation of the four-membered ring, and an η3-allylic interaction with the actinide. Complex solution-phase dynamics are observed with multinuclear nuclear magnetic resonance spectroscopy for both sandwich complexes. A computational analysis of the reaction mechanism leading to the formation of 4 and 5 indicates that the cyclobutadienyl ligands undergo C–H activation across the actinide center.

Published
2022
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16. Unusual selective reactivity of the rare-earth metal complexes bearing a ligand with multiple functionalities

Author

Dongjing Hong, Thayalan Rajeshkumar, Shan Zhu, Zeming Huang, Shuangliu Zhou, Xiancui Zhu, Laurent Maron, Shaowu Wang, Anhui Normal 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)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and Anhui Polytechnic University

Subjects
indole, Fischer-type carbene, rare-earth metal complexes, [CHIM]Chemical Sciences, dianionic 3-iminoindolyl, General Chemistry, N-heterocyclic carbene, 1-migratory insertion
Abstract

International audience; Ligands play a key role in controlling activity of organometallic complexes so that development of new ligands to overcome the challenge is the main topic of modern chemistry. The first example of 1,1-hydride migratory insertion and intramolecular redox reaction has been realized in this work by applying a new ligand in rare-earth metal chemistry. The novel rare-earth metal complexes LMesRECH2TMS(THF) (RE = Y (1a), Dy (1b), Er (1c), Yb (1d), LMes = 1-(3-(2,6-iPr2C6H3N=CH)C8H4N)-CH2CH2-3-(2-CH2—4,6-Me2C6H2)-(N(CH)2NC), THF = tetrahydrofuran) bearing a ligand with imino, indolyl, NHC (N-heterocyclic carbene) multiple functionalities were synthesized and characterized. Treatment of complexes 1 with silanes (PhSiH3 or PhSiH2Me or PhSiD3) selectively produced the unprecedented 1,1-hydride (or deuterated H) migratory insertion of the indolyl moiety of the novel unsymmetrical dinuclear rare-earth metal complexes 2. The complex 2a reacts with Ph2C-O to give the selective C-O double bond insertion to the RE-Co-methylene-Mes bond product 3a which further reacts with another Ph2C-O (or DMAP, 4-N, N-dimethylaminopyridine) affording the novel μ-η2:η3-dianionic 3-iminoindolyl dinuclear rare-earth metal complex 4a. The latter is formed through an unusual intramolecular redox reaction (through electron migration from the 2-carbanion of the indolyl ring to the imino motif) resulting in the re-aromatization of the indolyl ring.

Published
2022
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17. Evidence for single metal two electron oxidative addition and reductive elimination at uranium

Author

Benedict M. Gardner, Christos E. Kefalidis, Erli Lu, Dipti Patel, Eric J. L. McInnes, Floriana Tuna, Ashley J. Wooles, Laurent Maron, and Stephen T. Liddle

Subjects
Science
Abstract

The reactivity of f-block complexes is primarily defined by single-electron oxidations and σ-bond metathesis. Here, Liddle and co-workers provide evidence that a uranium complex can undergo reversible oxidative addition and reductive elimination, demonstrating transition metal-like reactivity within f-block chemistry.

Published
2017
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18. Stereospecific Polymerization of Bulky Methacrylates Using Organocatalyst in Strong Donating Solvent via Self-Controlled Mechanism

Author

Yangyang Sun, Ambre Carpentier, Yixin Zhang, Biwei Weng, Yaoyao Ling, Laurent Maron, Miao Hong, 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)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and University of Chinese Academy of Sciences [Beijing] (UCAS)

Subjects
Polymers and Plastics, Organic Chemistry, COORDINATION POLYMERIZATION, ANIONIC-POLYMERIZATION, PROTON-TRANSFER POLYMERIZATION, MEDIATED POLYMERIZATION, METHYL-METHACRYLATE, LIVING POLYMERIZATION, Inorganic Chemistry, N-HETEROCYCLIC CARBENES, Materials Chemistry, [CHIM]Chemical Sciences, RADICAL POLYMERIZATION, (METH)ACRYLIC MONOMERS, POLAR DIVINYL MONOMERS
Published
2022
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20. Coordination and Activation of N2 at Low-Valent Magnesium using a Cooperative Heterobimetallic Approach: Synthesis and Reactivity of a Masked Dimagnesium Diradical

Author

Rahul Mondal, Matthew J Evans, Thayalan Rajeshkumar, Laurent Maron, and Cameron Jones

Abstract

The activation of dinitrogen (N2) by transition metals is central to the highly energy intensive, heterogenous Haber-Bosch process. Considerable progress has been made towards more sustainable homogeneous activations of N2 with d- and f-block metals, though little success has been had with main group metals. Here we report that the reduction of a bulky magnesium(II) amide [(TCHPNON)Mg] (TCHPNON = 4,5-bis(2,4,6-tricyclohexylanilido)-2,7-diethyl-9,9-dimethyl-xanthene) with 5% w/w K/KI yields the magnesium-N2 complex [{K(TCHPNON)Mg}2(-N2)]. DFT calculations and experimental data show that the dinitrogen unit in the complex has been reduced to the N22- dianion, via a transient anionic magnesium(I) radical. The compound readily reductively activates CO, H2 and C2H4, in reactions in which it acts as a masked dimagnesium(I) diradical.

Published
2023
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21. Exploring the Redox Properties of Bench-Stable Uranyl(VI) Diamido–Dipyrrin Complexes

Author

Karlotta van Rees, Emma K. Hield, Ambre Carpentier, Laurent Maron, Stephen Sproules, and Jason B. Love

Subjects
Inorganic Chemistry, Physical and Theoretical Chemistry
Abstract

The uranyl complexes UO2(OAc)(L) and UO2Cl(L) of the redox-active, acyclic diamido–dipyrrin anion L– are reported and their redox properties explored. Because of the inert nature of the complexes toward hydrolysis and oxidation, synthesis of both the ligands and complexes was conducted under ambient conditions. Voltammetric, electron paramagnetic resonance spectroscopy, and density functional theory studies show that one-electron chemical reduction by the reagent CoCp2 leads to the formation of a dipyrrin radical for both complexes [Cp2Co][UO2(OAc)(L•)] and [Cp2Co][UO2Cl(L•)].

Published
2022
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22. A Route to Stabilize Uranium(II) and Uranium(I) Synthons in Multimetallic Complexes

Author

R. A. Keerthi Shivaraam, Megan Keener, Dieuwertje K. Modder, Thayalan Rajeshkumar, Ivica Živković, Rosario Scopelliti, Laurent Maron, and Marinella Mazzanti

Subjects
General Medicine, General Chemistry, Catalysis
Abstract

Herein, we report the redox reactivity of a multimetallic uranium complex supported by triphenylsiloxide (−OSiPh3) ligands, where we show that low valent synthons can be stabilized via an unprecedented mechanism involving intramolecular ligand migration. The two- and three-electron reduction of the oxo-bridged diuranium(IV) complex [{(Ph3SiO)3(DME)U}2(μ-O)], 4, yields the formal “UII/UIV”, 5, and “UI/UIV”, 6, complexes via ligand migration and formation of uranium-arene δ-bond interactions. Remarkably, complex 5 effects the two-electron reductive coupling of pyridine affording complex 7, which demonstrates that the electron-transfer is accompanied by ligand migration, restoring the original ligand arrangement found in 4. This work provides a new method for controlling the redox reactivity in molecular complexes of unstable, low-valent metal centers, and can lead to the further development of f-elements redox reactivity.

Published
2023
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23. Magnesium(I) Reduction of Aluminum(III) Hydride Complexes: Generation of Mixed Valence Aluminum (AlI/Al0) Hydride Cluster Compounds, [Al6H8(NR3)2{Mg(-diketiminate)}4]

Author

Sneha Mullassery, K. Yuvaraj, Deepak Dange, Dafydd Jones, Iker del Rosal, Ross Piltz, Alison Edwards, Laurent Maron, and Cameron Jones

Subjects
General Chemistry, General Medicine, Catalysis
Abstract

Reduction of a range of amido- and aryloxy-aluminum dihydride complexes, e.g. [AlH2(NR3){N(SiMe3)2}] (NR3 = NMe3 or N-methylpiperidine (NMP)), with -diketiminato dimagnesium(I) reagents, [{(ArNacnac)Mg}2] (ArNacnac = [HC(MeCNAr)2]-, Ar = mesityl (Mes) or 2,6-xylyl (Xyl)), have afforded deep red mixed valence aluminum hydride cluster compounds, [Al6H8(NR3)2{Mg(ArNacnac)}4], which have an average Al oxidation state of +0.66, the lowest for any well-defined aluminum hydride compound. In the solid-state, the clusters are shown to have distorted octahedral Al6 cores, having zero-valent Al axial sites and mono-valent AlH2- equatorial units. Several novel by-products were isolated from the reactions that gave the clusters, including the Mg‒Al bonded magnesio-aluminate complexes, [(ArNacnac)(Me3N)Mg‒Al(-H)3[{Mg(ArNacnac)}2(-H)]]. Computational analyses of one aluminum hydride cluster revealed its Al6 core to be electronically delocalized, and to possess one unoccupied, and six occupied, skeletal molecular orbitals.

Published
2023
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24. Magnesium(I) Reduction of Aluminum(III) Hydride Complexes: Generation of Mixed Valence Aluminum (AlI/Al0) Hydride Cluster Compounds, [Al6H8(NR3)2{Mg(-diketiminate)}4]

Author

Cameron Jones, Sneha Mullassery, K. Yuvaraj, Deepak Dange, Dafydd Jones, Thayalan Rajeshkumar, Iskander Douair, Ross Piltz, Alison Edwards, and Laurent Maron

Abstract

Reduction of a range of amido- and aryloxy-aluminum dihydride complexes, e.g. [AlH2(NR3){N(SiMe3)2}] (NR3 = NMe3 or N-methylpiperidine (NMP)), with -diketiminato dimagnesium(I) reagents, [{(ArNacnac)Mg}2] (ArNacnac = [HC(MeCNAr)2]-, Ar = mesityl (Mes) or 2,6-xylyl (Xyl)), have afforded deep red mixed valence aluminum hydride cluster compounds, [Al6H8(NR3)2{Mg(ArNacnac)}4], which have an average Al oxidation state of +0.66, the lowest for any well-defined aluminum hydride compound. In the solid-state, the clusters are shown to have distorted octahedral Al6 cores, having zero-valent Al axial sites and mono-valent AlH2- equatorial units. Several novel by-products were isolated from the reactions that gave the clusters, including the Mg‒Al bonded magnesio-aluminate complexes, [(ArNacnac)(Me3N)Mg‒Al(-H)3[{Mg(ArNacnac)}2(-H)]]. Computational analyses of one aluminum hydride cluster revealed its Al6 core to be electronically delocalized, and to possess one unoccupied, and six occupied, skeletal molecular orbitals.

Published
2023
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25. Molybdenum Carbonyl Assisted Reductive Tetramerization of CO by Activated Magnesium(I) Compounds: Squarate Dianion vs. Metallo-Ketene Formation

Author

K Yuvaraj, Jeremy Mullins, Thayalan Rajeshkumar, Iskander Douair, Laurent Maron, and Cameron Jones

Abstract

Reactions of a dimagnesium(I) compound, [{(DipNacnac)Mg}2] (DipNacnac = [HC(MeCNDip)2]-, Dip = 2,6-diisopropylphenyl), pre-activated by coordination with simple Lewis bases (4-dimethylaminopyridine, DMAP; or TMC, :C(MeNCMe)2), with 1 atmosphere of CO in the presence of one equivalent of Mo(CO)6 at room temperature, led to the reductive tetramerisation of the diatomic molecule. When the reactions were carried out at room temperature, there is an apparent competition between the formation of magnesium squarate, [{(DipNacnac)Mg}(C4O4){-Mg(DipNacnac)}]2, and magnesium metallo-ketene products, [{(DipNacnac)Mg}{-(C4O4)Mo(CO)5}{Mg(D)(DipNacnac)}], which are not inter-convertible. Repeating the reactions at 80 °C led to the selective formation of the magnesium squarate, implying that this is the thermodynamic product. In an analogous reaction, in which THF is the Lewis base, only the metallo-ketene complex, [{(DipNacnac)Mg}{-(C4O4)Mo(CO)5}{Mg(THF)(DipNacnac)}] is formed at room temperature, while a complex product mixture is obtained at elevated temperature. In contrast, treatment of a 1:1 mixture of the guanidinato magnesium(I) complex, [(Priso)Mg‒Mg(Priso)] (Priso = [Pri2NC(NDip)2]-), and Mo(CO)6, with CO gas in a benzene/THF solution, gave a low yield of the squarate complex, [{(Priso)(THF)Mg}(C4O4){-Mg(THF)(Priso)}]2, at 80 °C. Computational analyses of the electronic structure of squarate and metallo-ketene product types corroborate the bonding proposed, from experimental data, for the C4O4 fragments of these systems.

Published
2023
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28. Reductive activation of N2 using a calcium/potassium bimetallic system supported by an extremely bulky diamide ligand

Author

Rahul Mondal, K. Yuvaraj, Thayalan Rajeshkumar, Laurent Maron, 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)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
spectroscopy, Materials Chemistry, Metals and Alloys, Ceramics and Composites, [CHIM]Chemical Sciences, General Chemistry, nitrogen, Catalysis, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials
Abstract

An extremely bulky xanthene bridged diamide ligand ((NON)-N-TCHP = 4,5-bis(2,4,6-tricyclohexylanilido)-2,7-diethyl-9,9-dimethyl-xanthene) has been developed and used to prepare two monomeric diamido-calcium complexes [((NON)-N-TCHP)Ca(D)(n)] (D = THF, n = 2, 3; D = toluene, n = 1, 4). Reduction of 4 with 5% w/w K/KI under an N-2 atmosphere gave the first well-defined, hetero-bimetallic s-block complex of activated dinitrogen, [{K((NON)-N-TCHP)Ca}(2)(mu-eta(2):eta(2)-N-2)] 5, presumably via a transient calcium(i) intermediate.

Published
2022
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29. Electronic structure studies reveal 4f/5d mixing and its effect on bonding characteristics in Ce-imido and -oxo complexes

Author

Liane M. Moreau, Ekaterina Lapsheva, Jorge I. Amaro-Estrada, Michael R. Gau, Patrick J. Carroll, Brian C. Manor, Yusen Qiao, Qiaomu Yang, Wayne W. Lukens, Dimosthenis Sokaras, Eric J. Schelter, Laurent Maron, Corwin H. Booth, Lawrence Berkeley National Laboratory, Chemical Sciences Division, Lawrence, Department of Chemistry, The Pennsylvania State University, Pennsylvania State University (Penn State), Penn State System-Penn State System, 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)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Stanford Synchrotron Radiation Lightsource (SSRL SLAC), SLAC National Accelerator Laboratory (SLAC), Stanford University-Stanford University, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences, Quantum Information Systems Program of the U.S. Department of Energy (DOE) at LBNL [DE-AC02-05CH11231], National Science Foundation [CHE1955724], Office of Basic Energy Sciences, Chemical Sciences, Geosciences and Biosciences Division, Materials and Chemical Sciences Research for Quantum Information Science Program, of the U.S. Department of Energy [DE-SC0020169], and University of Pennsylvania

Subjects
Chemical Sciences, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], General Chemistry
Abstract

This study presents the role of 5d orbitals in the bonding, and electronic and magnetic structure of Ce imido and oxo complexes synthesized with a tris(hydroxylaminato) [((2- t BuNO)C6H4CH2)3N]3- (TriNO x 3-) ligand framework, including the reported synthesis and characterization of two new alkali metal-capped Ce oxo species. X-ray spectroscopy measurements reveal that the imido and oxo materials exhibit an intermediate valent ground state of the Ce, displaying hallmark features in the Ce LIII absorption of partial f-orbital occupancy that are relatively constant for all measured compounds. These spectra feature a double peak consistent with other formal Ce(iv) compounds. Magnetic susceptibility measurements reveal enhanced levels of temperature-independent paramagnetism (TIP). In contrast to systems with direct bonding to an aromatic ligand, no clear correlation between the level of TIP and f-orbital occupancy is observed. CASSCF calculations defy a conventional van Vleck explanation of the TIP, indicating a single-reference ground state with no low-lying triplet excited state, despite accurately predicting the measured values of f-orbital occupancy. The calculations do, however, predict strong 4f/5d hybridization. In fact, within these complexes, despite having similar f-orbital occupancies and therefore levels of 4f/5d hybridization, the d-state distributions vary depending on the bonding motif (Ce[double bond, length as m-dash]O vs. Ce[double bond, length as m-dash]N) of the complex, and can also be fine-tuned based on varying alkali metal cation capping species. This system therefore provides a platform for understanding the characteristic nature of Ce multiple bonds and potential impact that the associated d-state distribution may have on resulting reactivity.

Published
2022
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30. Bonding and Reactivity in Terminal versus Bridging Arenide Complexes of Thorium Acting as Th II Synthons

Author

Fang‐Che Hsueh, Thayalan Rajeshkumar, Bastiaan Kooij, Rosario Scopelliti, Kay Severin, Laurent Maron, Ivica Zivkovic, and Marinella Mazzanti

Subjects
General Chemistry, General Medicine, Catalysis
Abstract

Thorium redox chemistry is extremely scarce due to the high stability of Th(IV). Here we report two unique examples of thorium arenide complexes prepared by reduction of a Th(IV)-siloxide complex in presence of naphthalene, the mononuclear arenide complex [K(OSi(OtBu)3)3Th(η6-C10H8)] (1) and the inverse-sandwich complex [K(OSi(OtBu)3)3Th]2(μ-η6,η6-C10H8)] (2). The electrons stored in these complexes allow the reduction of a broad range of substrates (N2O, AdN3, CO2, HBBN). Higher reactivity was found for the complex 1 which reacts with the diazoolefin IDipp=CN2 to yield the unexpected Th(IV) amidoalkynyl complex 5via a terminal N-heterocyclic vinylidene intermediate. This work showed that arenides can act as convenient redox-active ligands for implementing thorium-ligand cooperative multielectron transfer and that the reactivity can be tuned by the arenide binding mode.

Published
2023
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33. Isolation and redox reactivity of cerium complexes in four redox states

Author

Fang-Che Hsueh, Thayalan Rajeshkumar, Laurent Maron, Rosario Scopelliti, Andrzej Sienkiewicz, and Marinella Mazzanti

Subjects
metal, reductive disproportionation, ions, series, c-h activation, General Chemistry, carbon-dioxide, chemistry, ligand, lanthanide(iii), crystal-structures
Abstract

The chemistry of lanthanides is limited to one electron transfer reactions due to the difficulty of accessing multiple oxidation states. Here we report that a redox-active ligand combining three siloxides with an arene ring in a tripodal ligand can stabilize cerium complexes in four different redox states and can promote multielectron redox reactivity in cerium complexes. Ce(iii) and Ce(iv) complexes [(LO3)Ce(THF)] (1) and [(LO3)CeCl] (2) (LO3 = 1,3,5-(2-OSi((OBu)-Bu-t)(2)C6H4)(3)C6H3) were synthesized and fully characterized. Remarkably the one-electron reduction and the unprecedented two-electron reduction of the tripodal Ce(iii) complex are easily achieved to yield reduced complexes [K(2.2.2-cryptand)][(LO3)Ce(THF)] (3) and [K-2{(LO3)Ce(Et2O)(3)}] (5) that are formally "Ce(ii)" and "Ce(i)" analogues. Structural analysis, UV and EPR spectroscopy and computational studies indicate that in 3 the cerium oxidation state is in between +II and +III with a partially reduced arene. In 5 the arene is doubly reduced, but the removal of potassium results in a redistribution of electrons on the metal. The electrons in both 3 and 5 are stored onto d-bonds allowing the reduced complexes to be described as masked "Ce(ii)" and "Ce(i)". Preliminary reactivity studies show that these complexes act as masked Ce(ii) and Ce(i) in redox reactions with oxidizing substrates such as Ag+, CO2, I-2 and S-8 effecting both one- and two-electron transfers that are not accessible in classical cerium chemistry.

Published
2023
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34. On the Dehydrocoupling of Alkenylacetylenes Mediated by Various Samarocene Complexes: A Charming Story of Metal Cooperativity Revealing a Novel Dual Metal σ-Bond Metathesis Type of Mechanism (DM|σ-BM)

Author

Christos E. Kefalidis and Laurent Maron

Subjects
samarium, σ-bond metathesis, trienediyl, C–C coupling, mechanism, DFT calculations, bimetallic complexes, terminal alkynes, Inorganic chemistry, QD146-197
Abstract

The prevailing reductive chemistry of Sm(II) has been accessed and explored mostly by the use of samarocene precursors. The highly reducing character of these congeners, along with their Lewis acidity and predominantly ionic bonding, allows for the relatively facile activation of C–H bonds, as well as peculiar transformations of unsaturated substrates (e.g., C–C couplings). Among other important C–C coupling reactions, the reaction of phenylacetylene with different mono- or bimetallic samarocene complexes affords trienediyl complexes of the type {[(C5Me5)2Sm]2(µ-η2:η2-PhC4Ph)}. In contrast, when t-butylacetylene is used, uncoupled monomers of the type (C5Me5)2Sm(C≡C–tBu) were obtained. Although this type of reactivity may appear to be simple, the mechanism underlying these transformations is complex. This conclusion is drawn from the density functional theory (DFT) mechanistic studies presented herein. The operating mechanistic paths consist of: (i) the oxidation of each samarium center and the concomitant double reduction of the alkyne to afford a binuclear intermediate; (ii) the C–H scission of the acetylinic bond that lies in between the two metals; (iii) a dual metal σ-bond metathesis (DM|σ-SBM) process that releases H2; and eventually (iv) the C–C coupling of the two bridged μ-alkynides to give the final bimetallic trienediyl complexes. For the latter mechanistic route, the experimentally used phenylacetylene was considered first as well as the aliphatic hex-1-yne. More interestingly, we shed light into the formation of the mono(alkynide) complex, being the final experimental product of the reaction with t-butylacetylene.

Published
2015
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35. Role of the Meso Substituent in Defining the Reduction of Uranyl Dipyrrin Complexes

Author

Karlotta van Rees, Thayalan Rajeshkumar, Laurent Maron, Stephen Sproules, Jason B. Love, EaStCHEM School of Chemistry, University of St Andrews [Scotland], 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)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), WestCHEM, School of Chemistry, and University of Glasgow-University of Glasgow

Subjects
Inorganic Chemistry, uranium, reactivity, coordination, oxidation, behavior, [CHIM]Chemical Sciences, series, Physical and Theoretical Chemistry
Abstract

International audience; The uranyl complex UVIO2Cl(LMes) of the redox-active, acyclic dipyrrin–diimine anion LMes– [HLMes = 1,9-di-tert-butyl-imine-5-(mesityl)dipyrrin] is reported, and its redox property is explored and compared with that of the previously reported UVIO2Cl(LF) [HLF = 1,9-di-tert-butyl-imine-5-(pentafluorophenyl)dipyrrin] to understand the influence of the meso substituent. Cyclic voltammetry, electron paramagnetic resonance spectroscopy, and density functional theory studies show that the alteration from an electron-withdrawing meso substituent to an electron-donating meso substituent on the dipyrrin ligand significantly modifies the stability of the products formed after reduction. For UVIO2Cl(LMes), the formation of a diamond-shaped, oxo-bridged uranyl(V) dimer, [UVO2(LMes)]2 is seen, whereas in contrast, for UVIO2Cl(LF), only ligand reduction occurs. Computational modeling of these reactions shows that while ligand reduction followed by chloride dissociation occurs in both cases, ligand-to-metal electron transfer is favorable for UVIO2Cl(LMes) only, which subsequently facilitates uranyl(V) dimerization.

Published
2022
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36. Organotitanium Complexes Supported by a Dianionic Pentadentate Ligand

Author

Warren Piers, Daniel Beh, Alejandro Cuellar De Lucio, Iker del Rosal, Laurent Maron, Denis Spasyuk, Benjamin Gelfand, and Jian-Bin Li

Abstract

The tetrapyralzolylpyridyl diborate pentadentate ligand B2Pz4Py has been complexed to Ti(III) to form the chloro complex (B2Pz4Py)Ti(III)Cl, which is a convenient starting material for preparing alkyl and hydride derivatives of this ligand. The former (R = CH3 and CH2SiMe3) are highly thermally stable and do not react with dihydrogen to form (B2Pz4Py)Ti(III)H. Rather, treatment of the chloro starting material with NaHBEt3 affords the desired hydrido complex in 85% yield. This Ti(III) hydride was fully characterized and exists in both solution and the solid state as a dimeric species; dissociation into monomers faces a high barrier of over 40 kcal/mol, according to Density Function Theory computations. This is due to stabilization of the dimer by dispersion forces. The computations show that the dimer has an S = 1 ground state, but in solution, partial dissociation into an intermediate dimer which is an open shell singlet is possible, which accounts for the lower than expected magnetic susceptibility of 1.93 per dimer. Full dissociation into reactive monomers does not occur, based on the observed lack of reactivity with carbon dioxide. All of these com-pounds react with water to form a mu-oxo dinuclear species, which reacts further with dioxygen to form oxidized peroxo and oxo Ti(IV) complexes. All three of these compounds were fully characterized.

Published
2022
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37. Spectroscopic, Magnetic, and Computational Investigations on a Series of Rhenium(III) Cyclopentadienide β-diketiminate Halide and Pseudohalide Complexes

Author

Robert G. Bergman, John Arnold, Laurent Maron, Daniel J. Lussier, Khetpakorn Chakarawet, Jorge Ivan Amaro Estrada, Trevor D. Lohrey, Erik T. Ouellette, University of California (UC), Lawrence Berkeley National Laboratory [Berkeley] (LBNL), 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)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
MAIN-GROUP ELEMENTS, Series (mathematics), LAT ISOMERIZATION, TRANSITION-METALS, Organic Chemistry, MULTIPLE BONDS, chemistry.chemical_element, Halide, Rhenium, DFT CALCULATIONS, REACTIVITY, Inorganic Chemistry, β diketiminate, SOLID-STATE, X-RAY STRUCTURES, chemistry, RESONANCE SPECTRA, Polymer chemistry, [CHIM]Chemical Sciences, CRYSTAL-STRUCTURE, Physical and Theoretical Chemistry
Abstract

International audience; The low-valent rhenium(I) salt Na[Re(η5-Cp)(BDI)] (BDI = N,N′-bis(2,6-diisopropylphenyl)-3,5-dimethyl-β-diketiminate) was shown to react with various halide and chalcogenolate reagents, leading to the isolation of a series of rhenium(III)–halide and −pseudohalide complexes: Re(X)(η5-Cp)(BDI) (1-X, X = F, Cl, Br, I; 2, X = OTf) and Re(ER)(η5-Cp)(BDI) (3-ER, ER = SBn, SeBn, TePh). The 1H NMR spectra of these complexes displayed sharp resonances shifted several ppm from typical diamagnetic regions, as well as distinct chemical shift trends down both the halide (with the exception of F) and chalcogenolate series, with both Cp and BDI backbone peaks moving downfield with increasing atomic number. Subsequent magnetic susceptibility measurements of the rhenium(III) halides 1-Cl, 1-Br, and 1-I indicated that these complexes display temperature-independent paramagnetism (TIP), with χTIP values of 7.41(44) × 10–4 to 1.50(51) × 10–3 cm3 mol–1. Multireference complete active space self-consistent field (CASSCF) computations incorporating spin–orbit state mixing revealed small energy separations (1.7–3.0 kcal/mol) between thermally isolated ground states and the first excited spin–orbit states for the rhenium halides, confirming that low-lying excited states are responsible for the observed TIP behavior.

Published
2022
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38. Facile Synthesis of Uranium Complexes with a Pendant Borane Lewis Acid and 1,2‐Insertion of CO into a U−N Bond

Author

Wei Su, Thayalan Rajeshkumar, Libo Xiang, Laurent Maron, Qing Ye, Anhui Polytechnic University, Southern University of Science and Technology (SUSTech), 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)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and Julius-Maximilians-Universität Würzburg (JMU)

Subjects
Carbon Monoxide, ddc:540, Uranium, [CHIM]Chemical Sciences, General Medicine, General Chemistry, Boranes, Catalysis, Boron, Lewis Acids
Abstract

In this contribution, we illustrate uranium complexes bearing a pendant borate (i.e. 1 and 2) or a pendant borane (i.e. 3 and 4) moiety via reaction of the highly strained uranacycle I with various 3-coordinate boranes. Complexes 3 and 4 represent the first examples of uranium complexes with a pendant borane Lewis acid. Moreover, complex 3 was capable of activation of CO, delivering a new CO activation mode, and an abnormal CO 1,2-insertion pathway into a U-N bond. The importance of the pendant borane moiety was confirmed by the controlled experiments.

Published
2022
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39. Elemental chalcogen reactions of a tetravalent uranium imidophosphorane complex: cleavage of dioxygen

Author

Luis M. Aguirre Quintana, Thayalan Rajeshkumar, Ningxin Jiang, Julie E. Niklas, John Bacsa, Laurent Maron, Henry S. La Pierre, School of Chemistry and Biochemistry [Atlanta], Georgia Institute of Technology [Atlanta], 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)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and George W. Woodruff School of Mechanical Engineering

Subjects
Organoimido, Reactivity, Metals and Alloys, Activation, General Chemistry, Catalysis, Atom-transfer, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Oxygen, Materials Chemistry, Ceramics and Composites, Uranyl-ion, [CHIM]Chemical Sciences, Uranium, Chalcogens, Sulfur, SE, Analogs
Abstract

Herein we report the first example of a mononuclear uranium complex, [U4+(NP(pip)3)4] (1-U), that selectively reduces dioxygen to produce a terminal oxo complex, [U6+O(NP(pip)3)4] (2-U; [NP(pip)3]1− is tris(piperidinyl)imidophosphorane). Reactions between 1-U and the heavier elemental chalcogens, S8 or Se0, result in six-coordinate U(VI) complexes, [U6+(κ2-E3)(NP(pip)3)4] (E = S (3-U) or Se (4-U)).

Published
2022
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40. [(Me 6 TREN)MgOCHPh 2 ][B(C 6 F 5 ) 4 ]: A Model Complex to Explore the Catalytic Activity of Magnesium Alkoxides in Ketone Hydroboration

Author

Raju Chambenahalli, Ankur, R Kannan, Ajay Venugopal, Yan Yang, Sumanta Banerjee, and Laurent Maron

Subjects
Inorganic Chemistry, chemistry.chemical_classification, Hydroboration, Reaction mechanism, Alkaline earth metal, Ketone, chemistry, Magnesium, Organic chemistry, chemistry.chemical_element, Catalysis
Published
2021
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41. Reversible Oxidative Addition of Zinc Hydride at a Gallium(I)‐Centre: Labile Mono‐ and Bis(hydridogallyl)zinc Complexes

Author

Louis J. Morris, Thayalan Rajeshkumar, Laurent Maron, Jun Okuda, Institute of Inorganic Chemistry [Aachen] (IAC RWTH), Rheinisch-Westfälische Technische Hochschule Aachen University (RWTH), Chemistry Research Laboratory [Oxford, UK], University of Oxford, 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)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
gallium, ddc:540, Organic Chemistry, zinc, hydrides, [CHIM]Chemical Sciences, General Chemistry, heterometallic complexes, Catalysis
Abstract

Chemistry - a European journal 28(56), e202201480 (2022). doi:10.1002/chem.202201480, Published by Wiley-VCH, Weinheim

Published
2022
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42. Assembling diuranium complexes in different states of charge with a bridging redox-active ligand

Author

Dieuwertje K. Modder, Mikhail S. Batov, Thayalan Rajeshkumar, Andrzej Sienkiewicz, Ivica Zivkovic, Rosario Scopelliti, Laurent Maron, Marinella Mazzanti, Institut des Sciences et Ingénierie Chimiques (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), 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)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratory for Quantum Magnetism, and ADS resonances Sàrl

Subjects
SINGLE-MOLECULE-MAGNET, ELECTRONIC-STRUCTURE, DILANTHANIDE COMPLEXES, OXO COMPLEXES, [CHIM]Chemical Sciences, U-IV-E, General Chemistry, GROUND-STATES, EXCHANGE, URANIUM(III) COMPLEX, COORDINATION-COMPLEXES, LANTHANIDE(III)/ACTINIDE(III) DIFFERENTIATION
Abstract

Radical-bridged diuranium complexes are desirable for their potential high exchange coupling and single molecule magnet (SMM) behavior, but remain rare. Here we report for the first time radical-bridged diuranium(IV) and diuranium(III) complexes. Reaction of [U{N(SiMe3)(2)}(3)] with 2,2'-bipyrimidine (bpym) resulted in the formation of the bpym-bridged diuranium(IV) complex [{((Me3Si)(2)N)(3)U-}2(IV)(mu-bpym(2-))], 1. Reduction with 1 equiv. KC8 reduces the complex, affording [K(2.2.2-cryptand)][{((Me3Si)(2)N)(3)U)(2)(mu-bpym)], 2, which is best described as a radical-bridged UIII-bpym center dot-U-III complex. Further reduction of 1 with 2 equiv. KC8, affords [K(2.2.2-cryptand)](2)[{((Me3Si)(2)N)(3)U-III}(2)(mu-bpym(2-))], 3. Addition of AgBPh4 to complex 1 resulted in the oxidation of the ligand, yielding the radical-bridged complex [{((Me3Si)(2)N)(3)U-IV}(2)(mu-bpym center dot-)][BPh4], 4. X-ray crystallography, electrochemistry, susceptibility data, EPR and DFT/CASSCF calculations are in line with their assignments. In complexes 2 and 4 the presence of the radical-bridge leads to slow magnetic relaxation.

Published
2022
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43. The mechanism of Fe induced bond stability of uranyl( v )

Author

Tonya Vitova, Radmila Faizova, Jorge I. Amaro-Estrada, Laurent Maron, Tim Pruessmann, Thomas Neill, Aaron Beck, Bianca Schacherl, Farzaneh Fadaei Tirani, Marinella Mazzanti, Karlsruhe Institute of Technology (KIT), Institut des Sciences et Ingénierie Chimiques (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), 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)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
COVALENCY, Technology, General Chemistry, SERIES, ELECTRONIC-STRUCTURE, REDUCTION, CHEMISTRY, U(VI), WYARTITE, FUNCTIONALIZATION, [CHIM]Chemical Sciences, COMPLEXES, ION, ddc:600
Abstract

The stabilization of uranyl(v) (UO21+) by Fe(ii) in natural systems remains an open question in uranium chemistry. Stabilization of UVO21+ by Fe(ii) against disproportionation was also demonstrated in molecular complexes. However, the relation between the Fe(ii) induced stability and the change of the bonding properties have not been elucidated up to date. We demonstrate that U(v) - oaxial bond covalency decreases upon binding to Fe(ii) inducing redirection of electron density from the U(v) - oaxial bond towards the U(v) - equatorial bonds thereby increasing bond covalency. Our results indicate that such increased covalent interaction of U(v) with the equatorial ligands resulting from iron binding lead to higher stability of uranyl(v). For the first time a combination of U M4,5 high energy resolution X-ray absorption near edge structure (HR-XANES) and valence band resonant inelastic X-ray scattering (VB-RIXS) and ab initio multireference CASSCF and DFT based computations were applied to establish the electronic structure of iron-bound uranyl(v).

Published
2022
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44. A Planar Nickelaspiropentane Complex with Magnesium-Based Metalloligands: Synthesis, Structure, and Synergistic Dihydrogen Activation

Author

Yanping Cai, Shengjie Jiang, Thayalan Rajeshkumar, Laurent Maron, Xin Xu, Soochow 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)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Colloid and Surface Chemistry, Catalysts, Mathematical methods, Nickel, [CHIM]Chemical Sciences, General Chemistry, Catalytic reactions, Biochemistry, Catalysis, Hydrocarbons
Abstract

The nature of transition-metal–olefin bonding has been explained by the Dewar–Chatt–Duncanson model within a continuum of two extremes, namely, a π-complex and a metallacyclopropane. The textbook rule suggests that a low-spin late-transition-metal–ethylene complex more likely forms a π-complex rather than a metallacyclopropane. Herein, we report a low-spin late-transition-metal–bis-ethylene complex forming an unprecedented planar metalla-bis-cyclopropane structure with magnesium-based metalloligands. Treatment of LMgEt (L = [(DippNCMe)2CH]−, Dipp = 2,6-iPr2C6H3) with Ni(cod)2 (cod = 1,5-cyclooctadiene) formed the heterotrimetallic complex (LMg)2Ni(C2H4)2, which features a linear Mg–Ni–Mg linkage and a planar coordination geometry at the nickel center. Both structural features and computational studies strongly supported the Ni(C2H4)2 moiety as a nickelaspiropentane. The exposure of (LMg)2Ni(C2H4)2 to 1 bar H2 at room temperature produced a four-hydride-bridged complex (LMg)2Ni(μ-H)4. The profile of H2 activation was elucidated by density functional theory calculations, which indicated a novel Mg/Ni cooperative activation mechanism with no oxidation occurring at the metal center, differing from the prevailing mono-metal-based redox mechanism. Moreover, the heterotrimetallic complex (LMg)2Ni(C2H4)2 catalyzed the hydrogenation of a wide range of unsaturated substrates under mild conditions.

Published
2022
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45. Electron Shuttle in

Author

Maxime, Tricoire, Ding, Wang, Thayalan, Rajeshkumar, Laurent, Maron, Grégory, Danoun, and Grégory, Nocton

Abstract

Simple

Published
2022

46. Spontaneous Ammonia Activation Through Coordination‐Induced Bond Weakening in Molybdenum Complexes of a Dianionic Pentadentate Ligand Platform

Author

C. Christopher Almquist, Nicole Removski, Thayalan Rajeshkumar, Benjamin S. Gelfand, Laurent Maron, Warren E. Piers, Department of Chemistry, University of Calgary, 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)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Molybdenum, Ligand Design, [CHIM]Chemical Sciences, Density Functional Calculations, General Medicine, General Chemistry, Bond Activation, Ammonia Oxidation, Catalysis
Abstract

Ammonia oxidation catalyzed by molecular compounds is of current interest as a carbon-free source of dihydrogen. Activation of N-H bonds through coordination to transition metal centers is a key reaction in this process. We report the substantial activation of ammonia via reaction with low-valent molybdenum complexes of a diborate pentadentate ligand system. Spontaneous loss of dihydrogen from (B

Published
2022
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47. Molecular and Electronic Structure of Linear Uranium Metallocenes Stabilized by Pentabenzyl-Cyclopentadienyl Ligands

Author

Sascha T. Löffler, Frank W. Heinemann, Ambre Carpentier, Laurent Maron, Karsten Meyer, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), 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)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
ACTINIDE, DERIVATIVES, Organic Chemistry, METALLACYCLOCUMULENE, OXIDATION-STATE, REACTIVITY, Inorganic Chemistry, ACTIVATION, SPONTANEOUS REDUCTION, CONVERSION, CHEMISTRY, [CHIM]Chemical Sciences, COMPLEXES, Physical and Theoretical Chemistry
Abstract

We report a series of uranium complexes stabilized by the pentakis-benzyl-derivatized cyclopentadienyl ligand, CpBn5. Treatment of [UCl4] and [UI3(1,4-dioxane)1,5] with 2 equiv of the potassium salt, CpBn5K, yielded the corresponding complexes [(CpBn5)2UIV(Cl)2] (1) and [(CpBn5)2UIII(I)] (4). Subsequently, tetravalent 1 is either methylated to give [(CpBn5)2UIV(Me)2] (2) or reduced to form trivalent [(CpBn5)2UIII(μ-Cl)2K(OEt2)3] (3). Oxidation of 4 with AgI yields [(CpBn5)2UIV(I)2] (5), which was found to generate rarely observed, linear uranium metallocenes [(CpBn5)2UIV(NCMe)5][X]2 (X = PF6– (6), BPh4– (7)) upon abstraction of the iodide ligands with thallium salts in acetonitrile. All complexes were characterized by 1H NMR spectroscopy, CHN elemental analysis, UV–vis–NIR spectroscopy, and SQUID magnetization measurements. The solid-state molecular structures of 1–7 were determined by single-crystal X-ray diffraction analysis. An in-depth computational analysis revealed the peculiar electronic structure of the linearly coordinated title complex 7 and its closely related, parent [(Cp*)2UIV(NCMe3)5]2+ dication.

Published
2022
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48. Uranium(III)–Phosphorus(III) Synergistic Activation of White Phosphorus and Arsenic

Author

Shuao Wang, Wei Fang, Peter W. Roesky, Congqing Zhu, Iskander Douair, Laurent Maron, Kai Li, Adrian Hauser, Yue Zhao, Nanjing University (NJU), 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)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Karlsruhe Institute of Technology (KIT), and Soochow University

Subjects
chemistry, Transition metal, White Phosphorus, Environmental chemistry, Phosphorus, chemistry.chemical_element, [CHIM]Chemical Sciences, General Chemistry, Uranium, Arsenic
Abstract

The study of small-molecule activation by f-block elements still lags far behind that of transition metals. Although a few uranium complexes have been reported to activate dinitrogen, reports on th...

Published
2022
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50. Ytterbium (II) Hydride as a Powerful Multielectron Reductant

Author

Iskander Douair, Scott A. Cameron, Laurent Maron, Mathew D. Anker, Georgia M. Richardson, Victoria University of Wellington, 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)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Ytterbium, polyaromatic hydrocarbons, Hydrogen, Hydride, multielectron reduction, Organic Chemistry, naphthalene, Aromatization, chemistry.chemical_element, General Chemistry, Photochemistry, Catalysis, chemistry.chemical_compound, 7-cyclooctatetraene, Deprotonation, chemistry, ytterbium hydrides, Density functional theory, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Naphthalene
Abstract

International audience; A dimeric beta-diketiminato ytterbium(II) hydride affects both the two-electron aromatization of 1,3,5,7-cyclooctatetraene (COT) and the more challenging two-electron reduction of polyaromatic hydrocarbons, including naphthalene (E-0=-2.60 V). Confirmed by Density Functional Theory calculations, these reactions proceed via consecutive polarized Yb-H/C=C insertion and deprotonation steps to provide the respective ytterbium (II) inverse sandwich complexes and hydrogen gas. These observations highlight the ability of a simple ytterbium(II) hydride to act as a powerful two-electron reductant at room temperature without the necessity of an external electron to initiate the reaction and avoiding radicaloid intermediates.

Published
2021
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