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2. Back to the future of organolanthanide chemistry

Author

Nolwenn Mahieu, Jakub Piątkowski, Thomas Simler, and Grégory Nocton

Subjects
General Chemistry
Abstract

By taking inspiration from the structures and reactivities of its past, organolanthanide chemistry has managed to reinvent itself for the challenges of today and the future.

Published
2023
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4. Synthesis and Structures of Tris(cyclononatetraenyl) Rare-Earth Complexes [Ln(C9H9)3] (Ln = Y, Gd, Tb, Dy, Ho, Er, Tm)

Author

Oleh Stetsiuk, Léo La Droitte, Violaine Goudy, Boris Le Guennic, Olivier Cador, Grégory Nocton, Laboratoire de Cristallographie Macromoléculaire (LCM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), 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), ANR (French National Research Agency) French National Research Agency (ANR) [ANR-19-CE07-0019-1], CNRS Centre National de la Recherche Scientifique (CNRS) European Commission, Ecole polytechnique, and ANR-19-CE07-0019,RelaxMax,Complexes organométalliques de lanthanides à relaxation magnétique lente(2019)

Subjects
Inorganic Chemistry, Organic Chemistry, [CHIM]Chemical Sciences, Physical and Theoretical Chemistry
Abstract

International audience; The article reports the synthesis and structural characterization of a series of Ln(C9H9)(3) complexes with the cyclononatetraenyl (Cnt, C9H9) ligand (Ln = Y, Gd, Tb, Dy, Ho, Er, Tm). The Yb and Sm complexes were not obtained, and the reaction of the potassium salt of the Cnt ligand with trivalent halide salts of the corresponding metals led to the known bis-Cnt sandwich compounds Ln(C9H9)(2). The X-ray diffraction studies on the trivalent complexes show that the Cnt ligand is significantly bent in order to accommodate the large size of the ligand while it maintains its aromaticity. When the size of the lanthanide ion decreases, the ligand does not switch away but swings over the metal ion in order to maximize the electrostatic interactions. H-1 NMR and UV-visible spectra, as well as the solid-state magnetism, were recorded. UV-visible spectroscopy highlights a remarkable charge-transfer band in the Tm complex, while ligand-based transitions are principally observed with all other metal ions. The magnetic behavior of the series agrees with trivalent lanthanide ions, and the computations at the CASSCF level confirm the trivalent electronic structure.

Published
2022
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5. Molecular Lanthanide Switches for Magnetism and Photoluminescence

Author

Luca Münzfeld, Milena Dahlen, Adrian Hauser, Nolwenn Mahieu, Senthil Kumar Kuppusamy, Jules Moutet, Maxime Tricoire, Ralf Köppe, Léo La Droitte, Olivier Cador, Boris Le Guennic, Grégory Nocton, Eufemio Moreno‐Pineda, Mario Ruben, Peter W. Roesky, Karlsruher Institut für Technologie (KIT), Institut Polytechnique de Paris (IP Paris), 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), Universidad de Panamá (UP), KIT is acknowledged for financial support. MD thanks the Fonds der Chemischen Industriefor the generous fellowship (No. 103581). AH, MR, and PR gratefully acknowledge financial support from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) through the Collaborative Research Centre \'4f for Future\' (CRC 1573, project number 471424360) projects C1 and B2. E.M.-P. thanks the Panamanian National System of Investigators (SNI, SENACYT) and SENACYT (project PFID-FID-2021-60) for support. Parts of this work have received funding from the ERC under grant agreement No 716314 and from an ANR (French National Research Agency) granted collaborative project (ANR-19-CE07-0019-1). CNRS and Ecole polytechnique are thanked for financial support. NM thanks ENS Paris-Saclay., and ANR-19-CE07-0019,RelaxMax,Complexes organométalliques de lanthanides à relaxation magnétique lente(2019)

Subjects
Chemistry & allied sciences, Magnetism, Sandwich Compounds, General Chemistry, General Medicine, Lanthanides, Catalysis, Molecular switches, Sandwich compounds, ddc:540, [CHIM]Chemical Sciences, Photoluminescence, Molecular Switches
Abstract

Solvation of [(CNT)Ln(η$^8$-COT)] (Ln=La, Ce, Nd, Tb, Er; CNT=cyclononatetraenyl, i.e., C$_9$H$_9$−; COT=cyclooctatetraendiid, i.e., C$_8$H$_8$$^2−$) complexes with tetrahydrofuran (THF) gives rise to neutral [(η$^4$-CNT)Ln(thf)$_2$(η$^8$-COT)] (Ln=La, Ce) and ionic [Ln(thf)$_x$(η$^8$-COT)][CNT] (x=4 (Ce, Nd, Tb), 3 (Er)) species in a solid-to-solid transformation. Due to the severe distortion of the ligand sphere upon solvation, these species act as switchable luminophores and single-molecule magnets. The desolvation of the coordinated solvents can be triggered by applying a dynamic vacuum, as well as a temperature gradient stimulus. Raman spectroscopic investigations revealed fast and fully reversible solvation and desolvation processes. Moreover, we also show that a Nd:YAG laser can induce the necessary temperature gradient for a self-sufficient switching process of the Ce(III) analogue in a spatially resolved manner.

Published
2023
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6. Reactive Heterobimetallic Complex Combining Divalent Ytterbium and Dimethyl Nickel Fragments

Author

Ding Wang, Jules Moutet, Maxime Tricoire, Marie Cordier, and Grégory Nocton

Subjects
divalent lanthanides, redox non-innocent ligand, magnetism, CO insertion, Inorganic chemistry, QD146-197
Abstract

This article presented the synthesis and characterization of original heterobimetallic species combining a divalent lanthanide fragment and a divalent nickel center bridged by the bipyrimidine ligand, a redox-active ligand. X-ray crystal structures were obtained for the Ni monomer (bipym)NiMe2, 1, as well as the heterobimetallic dimer compounds, Cp*2Yb(bipym)NiMe2, 2, along with 1H solution NMR, solid-state magnetic data, and DFT calculations only for 1. The reactivity with CO was investigated on both compounds and the stoichiometric acetone formation is discussed based on kinetic and mechanistic studies. The key role of the lanthanide fragment was demonstrated by the relatively slow CO migratory insertion step, which indicated the stability of the intermediate.

Published
2019
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7. Electron Shuttle in

Author

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

Abstract

Simple

Published
2022

9. Phenylacetylene and Carbon Dioxide Activation by an Organometallic Samarium Complex

Author

Violaine Goudy, Mathieu Xémard, Simon Karleskind, Marie Cordier, Carlos Alvarez Lamsfus, Laurent Maron, and Grégory Nocton

Subjects
small molecule activation, samarium complexes, C–H activation, Inorganic chemistry, QD146-197
Abstract

Small molecule activation is a topic of growing importance and the use of low-valent f-elements to perform these reactions is nowadays well established. The complex Cptt2Sm(thf) (1, Cptt = 1,3-(tBu)2Cp) is shown to activate the alkyne C–H bond of phenylacetylene to form the Cptt2Sm(C≡C–Ph)(thf) complex. The subsequent reaction of this Sm(III) complex with CO2 leads to the CO2 insertion, yielding a dimeric [Cptt2Sm(O2C–C≡C–Ph)]2 complex (2), in which the carbon dioxide has been inserted in the Sm–C bond. Along with the experimental chemical structure analysis, theoretical calculations have been performed in order to rationalize the formation of 1 and 2.

Published
2018
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11. Electron Shuttle in N-Heteroaromatic Ni Catalysts for Alkene Isomerization

Author

Maxime Tricoire, Ding Wang, Thayalan Rajeshkumar, Laurent Maron, Grégory Danoun, Grégory Nocton, Laboratoire de chimie moléculaire (LCM), École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-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
nickel, catalysis, [CHIM.ORGA]Chemical Sciences/Organic chemistry, redox-active ligand, [CHIM.COOR]Chemical Sciences/Coordination chemistry, [CHIM.CATA]Chemical Sciences/Catalysis, alkene isomerization, heterometallic complexes
Abstract

International audience; Simple N-heteroaromatic Ni(II) precatalysts, (L)NiMe2 (L = bipy, bipym), were used for alkene isomerization. With an original reduction method using a simple borane (HB(Cat)), a low-valent Ni center was formed readily and showed good conversion when a reducing divalent lanthanide fragment, Cp*2Yb, was coordinated to the (bipym)NiMe2 complex, a performance not achieved by the monometallic (bipy)NiMe2 analogue. Experimental mechanistic investigations and computational studies revealed that the redox non-innocence of the L ligand triggered an electron shuttle process, allowing the elusive formation of Ni(I) species that were central to the isomerization process. Additionally, the reaction occurred with a preference for mono-isomerization rather than chain-walking isomerization. The presence of the low-valent ytterbium fragment, which contributed to the formation of the electron shuttle, strongly stabilized the catalysts, allowing catalytic loading as low as 0.5%. A series of alkenes with various architectures have been tested. The possibility to easily tune the various components of the heterobimetallic catalyst reported here, the ligand L and the divalent lanthanide fragment, opens perspectives for further applications in catalysis induced by Ni(I) species.

Published
2022
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13. Understanding the Multiconfigurational Ground and Excited States in Lanthanide Tetrakis Bipyridine Complexes from Experimental and CASSCF Computational Studies

Author

Laurent Maron, Richard A. Andersen, Grégory Nocton, Corwin H. Booth, J. I. Amaro-Estrada, Robert L. Halbach, Department of Chemistry [Berkeley], University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Laboratoire de chimie moléculaire (LCM), École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Chemical Sciences Division [LBNL Berkeley] (CSD), Lawrence Berkeley National Laboratory [Berkeley] (LBNL), University of California [Berkeley], University of California-University of California, Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)

Subjects
Lanthanide, 010405 organic chemistry, Electronic structure, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, Magnetic susceptibility, 0104 chemical sciences, Square antiprism, Inorganic Chemistry, Bipyridine, chemistry.chemical_compound, Crystallography, chemistry, Excited state, Molecular orbital, Physical and Theoretical Chemistry, Isostructural
Abstract

International audience; An alternative synthesis for M(κ2-bipy)4 (M = La, Ce) and [Li(thf)4][M(κ2-bipy)4] (M = Tb, Dy) and the crystal structures for M = La, Ce, and Tb are described. The isomorphous and isostructural neutral molecules, M = La and Ce, are polymeric in the solid-state, as are those of M = Sm and Eu, which were reported in earlier work. The polymeric network is built from eight coordinate units whose geometry in all four cases is that of a square prism. The known molecules, M = Yb and Lu, are also polymeric, but the eight coordinate units have dodecahedral geometries. The structure of the anions in the separated ion pair, [Li(thf)4][M(κ2-bipy)4], in which Tb is reported in this work and Lu is known, are monomeric with geometries that are between that of a square antiprism and a dodecahdron. The electronic structure, from CASSCF multireference quantum mechanical calculations, shows that the electronic ground states for M = La and Lu are multiconfigurational spin doublets and those for the M = Ce and Yb are multiconfigurational spin triplets. This is confirmed by magnetic susceptibility studies as a function of temperature that are consistent with the metals (La, Ce, Sm, Tb, Dy, Yb, and Lu) being trivalent, as are the LIII-edge XANES spectra (Ce, Yb), and divalent for Eu. The multiconfigurational nature of the ground states, developed from CASSCF molecular orbital calculations, renders a single Lewis structure and a single reference molecular orbital representation misleading. The results from the multireference calculations are extended to the other lanthanide molecules and are the genesis of a new model for understanding the magnetic properties of these molecules.

Published
2019
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14. Size-Controlled Hapticity Switching in [Ln(C

Author

Maxime, Tricoire, Luca, Münzfeld, Jules, Moutet, Nolwenn, Mahieu, Léo, La Droitte, Eufemio, Moreno-Pineda, Frédéric, Gendron, Jeremy D, Hilgar, Jeffrey D, Rinehart, Mario, Ruben, Boris, Le Guennic, Olivier, Cador, Peter W, Roesky, and Grégory, Nocton

Subjects
single molecule magnets, Full Paper, magnetism, Hot Paper, cyclononatetraenyl, lanthanides, Full Papers, organometallics
Abstract

Sandwich complexes of lanthanides have recently attracted a considerable amount of interest due to their applications as Single Molecule Magnet (SMM). Herein, a comprehensive series of heteroleptic lanthanide sandwich complexes ligated by the cyclononatetraenyl (Cnt) and the cyclooctatetraenyl (Cot) ligand [Ln(Cot)(Cnt)] (Ln=Tb, Dy, Er, Ho, Yb, and Lu) is reported. The coordination behavior of the Cnt ligand has been investigated along the series and shows different coordination patterns in the solid‐state depending on the size of the corresponding lanthanide ion without altering its overall anisotropy. Besides the characterization in the solid state by single‐crystal X‐ray diffraction and in solution by 1H NMR, static magnetic studies and ab initio computational studies were performed., A series of trivalent lanthanide heteroleptic sandwich complexes with the cyclooctatetraenyl (Cot) and cyclononatetraenyl (Cnt) ligands shows a significant bending of the Cnt ligand when the size of the ion decreases, implying a size‐controlled hapticity switch.

Published
2021

16. Influence of a Lanthanide Ion on the Ni Site of a Heterobimetallic 3d–4f Mabiq Complex

Author

Stuart A. J. Boyce, Jules Moutet, Grégory Nocton, Corinna R. Hess, Lukas Niederegger, Thomas Simler, Laboratoire de chimie moléculaire (LCM), and Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)

Subjects
Lanthanide, 010405 organic chemistry, Chemistry, Ligand, 010402 general chemistry, 01 natural sciences, Article, 0104 chemical sciences, Ion, Inorganic Chemistry, Crystallography, [CHIM]Chemical Sciences, Physical and Theoretical Chemistry, Bimetallic strip, ComputingMilieux_MISCELLANEOUS
Abstract

This work presents the synthesis and characterization of a 3d-4f bimetallic complex based on the redox-active macrocyclic biquinazoline ligand, Mabiq. The mixed Yb-Ni complex, [(Cp*)(2)Yb(Mabiq)Ni]BArF (3), was synthesized upon reaction of [Ni(II)(Mabiq)]BArF (2) with Cp*(2)Yb(II)OEt(2). The molecular structures of 3 and its sister complex, [(Cp*)(2)Yb(Mabiq)Ni][(Cp*)(2)Yb(OTf)(2)] (1), confirmed the presence of a Yb(III) center and a reduced Ni-Mabiq unit. Spectroscopy (absorption and NMR), cyclic voltammetry and magnetic susceptibility studies were employed to analyze the electronic structure of 3, which is best described by the [(Cp*)(2)Yb(III)(Mabiq(•))Ni(II)](+) formulation. Notably, the ligand centered radical is delocalized over both the diketiminate and bipyrimidine units of the Mabiq ligand. The magnetic susceptibility and variable temperature NMR studies for 3 denote coupling between the Ni-Mabiq site and the peripheral Yb center – previously unobserved in 3d-3d Mabiq complexes. The complex nature of the exchange interactions is highlighted by the multiconfigurational ground state for 3, comprising nearly degenerate singlet and triplet states.

Published
2021
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17. Intermediate Valence States in Lanthanide Compounds

Author

Nolwenn Mahieu, Grégory Nocton, Maxime Tricoire, Thomas Simler, Laboratoire de chimie moléculaire (LCM), and Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)

Subjects
Lanthanide, spectroscopy, Valence (chemistry), 010405 organic chemistry, Chemistry, Organic Chemistry, theoretical computations, Theoretical models, General Chemistry, 010402 general chemistry, 01 natural sciences, Catalysis, Article, 0104 chemical sciences, Chemical physics, intermediate valence, Electronic effect, [CHIM]Chemical Sciences, lanthanides, Spectroscopy, organometallics
Abstract

Over more than 50 years, intermediate valence states in lanthanide compounds have often resulted in unexpected or puzzling spectroscopic and magnetic properties. Such experimental singularities could not be rationalised until new theoretical models involving multiconfigurational electronic ground states were established. In this minireview, the different singularities that have been observed among lanthanide complexes are highlighted, the models used to rationalise them are detailed and how such electronic effects may be adjusted depending on energy and symmetry considerations is considered. Understanding and tuning the ground-state multiconfigurational behaviour in lanthanide complexes may open new doors to modular and unusual reactivities.

Published
2020
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20. Bis-cyclooctatetraenyl Thulium(II): Highly Reducing Lanthanide Sandwich Single Molecule Magnets

Author

Léo La Droitte, Boris Le Guennic, Thomas Simler, Grégory Nocton, jules Schleinitz, Frédéric Gendron, Maxime Tricoire, Jules Moutet, Olivier Cador, and Carine Clavaguéra

Subjects
chemistry.chemical_classification, Lanthanide, Crystallography, Electron transfer, Materials science, Thulium, chemistry, Ligand, chemistry.chemical_element, Molecule, Single-molecule magnet, Small molecule, Divalent
Abstract

Divalent lanthanide organometallics are well known highly reducing compounds usually used for single electron transfer reactivity and small molecule activation. Thus, their very reactive nature prevented for many years the study of their physical properties, such as magnetic studies on a reliable basis. In this article, the access to rare organometallic sandwich compounds of TmII with the cyclooctatetraenyl (Cot) ligand impacts on the use of divalent organolanthanide compounds as an additional strategy for the design of performing Single Molecule Magnets (SMM). Herein, the first divalent thulium sandwich complex with f13 configuration behaving as a Single Molecule Magnet in absence of DC field is highlighted.

Published
2020
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21. Small molecule activation with divalent samarium triflate: a synergistic effort to cleave O2

Author

Elisa Louyriac, Grégory Nocton, Carine Clavaguéra, Mathieu Xémard, Laurent Maron, and Marie Cordier

Subjects
chemistry.chemical_classification, Lanthanide, 010405 organic chemistry, Salt (chemistry), chemistry.chemical_element, 010402 general chemistry, 01 natural sciences, Small molecule, 0104 chemical sciences, Divalent, Inorganic Chemistry, Samarium, Samarium triflate, chemistry, Cleave, Reductive cleavage, Polymer chemistry
Abstract

The divalent samarium triflate salt does not react with CO2 or water, but does react with traces of O2 or N2O to form a tetrameric bis-oxo samarium motif. The reaction with O2 is a 4e− reductive cleavage where the electrons are coming from four different samarium centers. This highlights a rare synergistic effect for cleaving O2, which has no precedent in divalent lanthanide complexes. Additionally, the addition of CO2 to the tetrameric bis-oxo intermediate leads to the formation of a tetrameric bis-carbonate samarium triflate. Thus, the concomitant reaction of CO2 with traces of O2 leads to the same bis-carbonate tetrameric assembly.

Published
2018
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22. Reductive Disproportionation of CO2 with Bulky Divalent Samarium Complexes

Author

Violaine Goudy, Augustin Braun, Grégory Nocton, Christos E. Kefalidis, Mathieu Xémard, Laurent Maron, Marie Cordier, Carine Clavaguéra, Elisa Louyriac, Louis Ricard, Maxime Tricoire, and Ludovic Castro

Subjects
chemistry.chemical_classification, 010405 organic chemistry, Dimer, Organic Chemistry, Inorganic chemistry, chemistry.chemical_element, Disproportionation, 010402 general chemistry, 01 natural sciences, Medicinal chemistry, 0104 chemical sciences, 3. Good health, Divalent, Adduct, Inorganic Chemistry, Samarium, Solvent, chemistry.chemical_compound, chemistry, Pyridine, Physical and Theoretical Chemistry, Diethyl ether
Abstract

The base-free divalent samarium complex Cptt2Sm (1; Cptt = 1,3-(tBu)2(C5H3)) has been synthesized in diethyl ether by salt metathesis of SmI2. Crystals of 1 suitable for X-ray study have been obtained by sublimation at 116 °C under reduced pressure. The dissolution of 1 in thf and pyridine solution leads to the solvent adducts Cptt2Sm(thf)2 (3) and Cptt2Sm(py) (4), respectively, while drying 3 under reduced pressure yields CpttSm(thf) (5). The reaction of CO2 with the base-free divalent samarium complexes Cptt2Sm (1) and Cpttt2Sm (2; Cpttt =1,2,4-(tBu)3(C5H2)) leads to the clean formation of bridged carbonate samarium dimers [Cpttt2Sm]2(μ-CO3) (7) and [Cptt2Sm]2(μ-CO3) (8). This is indicative of the reductive disproportionation of CO2 in both cases with release of CO. This contrasts with the formation of the oxalate-bridged samarium dimer reported from the reaction of CO2 with the Cp*2Sm(thf)2 complex. Otherwise, the reaction with CO does not proceed with the bulky complexes, while traces of O2 have led t...

Published
2017
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23. Redox activity of a dissymmetric ligand bridging divalent ytter-bium and reactive nickel fragments

Author

Jules Moutet, Ding Wang, Maxime Tricoire, Grégory Nocton, Valeriu Cemortan, Laboratoire de chimie moléculaire (LCM), and Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)

Subjects
chemistry.chemical_classification, Lanthanide, 010405 organic chemistry, Ligand, chemistry.chemical_element, 010402 general chemistry, 01 natural sciences, Article, 0104 chemical sciences, Divalent, Inorganic Chemistry, Nickel, Crystallography, chemistry.chemical_compound, Electron transfer, Deprotonation, chemistry, Moiety, [CHIM]Chemical Sciences, Homoleptic
Abstract

International audience; The reaction of a reactive nickel dimethyl 1 bearing a redox-active, dissymmetric ligand, which is obtained by deprotonation of 2-pyrimidin-2-yl-1H-benzimidazole (Hbimpm) with a divalent lanthanide complex, Cp* 2 Yb(OEt 2), affords an unprecedented, trimeric 2 with C(sp 3)-C(sp 3) bond formation between two ligands in an exo position. Meanwhile, the transient, dimeric species 3 can be isolated with the same ligand coupling fashion, however, with a drastic distorsion angle of the bimpm ligand and reactive NiMe 2 fragment, revealing the possible mechanism of this rearrangement. A much more stable dimeric congener, 5, with an exo ligand coupling, is synthesized in the presence of 18-crown-6, which captures the potassium counter ion. The CC coupling formation between two bimpm ligands results from the effective electron transfer from divalent lanthanide fragments. Without the divalent lanthanide, the reductive coupling occurs on a different carbon of the ligand, nicely showing the modulation of the spin density induced by the presence of the lanthanide ion. The electronic structures of these complexes are investigated by magnetic study (SQUID), indicating a 2 F 7/2 ground state for each ytterbium in all the heterometallics. This work firstly reports ligand coupling reactivity in a redox-active, yet dissymmetric system with divalent organolanthanides, and the reactive nickel moiety can impact the intriguing transition towards a stable homoleptic, trinulear lanthanide species.

Published
2020
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24. Atom economical coupling of benzophenone and N-heterocyclic aromatics with SmI 2

Author

Grégory Nocton, Nicolas Casaretto, Arnaud Jaoul, Carine Clavaguéra, Laurent Maron, Yan Yang, Institut de Chimie Physique (ICP), Institut de Chimie du CNRS (INC)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), Laboratoire de chimie moléculaire (LCM), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), 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 École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Reaction mechanism, 010405 organic chemistry, Phenanthroline, Metals and Alloys, General Chemistry, Reaction intermediate, 010402 general chemistry, 01 natural sciences, Catalysis, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, chemistry.chemical_compound, Bipyridine, chemistry, Computational chemistry, Pyridine, Atom, Materials Chemistry, Ceramics and Composites, Proton NMR, Benzophenone, [CHIM]Chemical Sciences
Abstract

International audience; The use of stoechiometric SmI 2 in combination with benzophenone and N-heterocyclic aromatics such as bipyridine, phenanthroline and neat pyridine allows the direct ortho-coupling of both partners in an atom economical reaction free of any other coupling additives. The transformation was investigated by 1 H NMR, X-ray studies and theoretical calculations providing reaction intermediates and the reaction mechanism.

Published
2020
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25. Cover Feature: Size‐Controlled Hapticity Switching in [Ln(C 9 H 9 )(C 8 H 8 )] Sandwiches (Chem. Eur. J. 54/2021)

Author

Jeffrey D. Rinehart, Jeremy D. Hilgar, Olivier Cador, Mario Ruben, Frédéric Gendron, Jules Moutet, Nolwenn Mahieu, Luca Münzfeld, Peter W. Roesky, Grégory Nocton, Léo La Droitte, Boris Le Guennic, Eufemio Moreno-Pineda, and Maxime Tricoire

Subjects
Feature (computer vision), Chemical physics, Chemistry, Organic Chemistry, Hapticity, Cover (algebra), General Chemistry, Catalysis
Published
2021
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26. Effect of Cations on the Structure and Electrocatalytic Response of Polyoxometalate-Based Coordination Polymers

Author

Grégoire Paille, Marc Fontecave, Caroline Mellot-Draznieks, Grégory Nocton, Maria Gomez-Mingot, Pierre Mialane, William Salomon, Anne Dolbecq, Catherine Roch-Marchal, Jérôme Marrot, Institut Lavoisier de Versailles (ILV), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Chaire Chimie des processus biologiques, Laboratoire de Chimie des Processus Biologiques (LCPB), Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de chimie moléculaire (LCM), and Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)

Subjects
chemistry.chemical_classification, 010405 organic chemistry, Coordination polymer, Stereochemistry, General Chemistry, Polymer, 010402 general chemistry, Condensed Matter Physics, 01 natural sciences, 0104 chemical sciences, Crystallography, chemistry.chemical_compound, [CHIM.POLY]Chemical Sciences/Polymers, chemistry, Covalent bond, Polyoxometalate, General Materials Science, Counterion, Isostructural
Abstract

International audience; A series of six hybrid polymers based on the mixed-valent {ε-PMoV8MoVI4O40Zn4} (εZn) Keggin unit have been synthesized under hydrothermal conditions using tritopic (1,3,5-benzenetricarboxylate (trim) or 1,3,5-benzenetribenzoate (BTB)) or ditopic (4,4′-biphenyldicarboxylate (biphen)) linkers and [M(bpy)3]2+ (M = Co, Ru) complexes as charge-compensating cations. (TBA)2[Co(C10H8N2)3][PMo12O37(OH)3Zn4](C27H15O6)4/3·1.5C27H18O6·24H2O (Co-ε(BTB)4/3) has a three-dimensional (3D) framework with two interpenetrated networks and is isostructural to (TBA)4[PMo12O37(OH)3Zn4](C27H15O6)4/3·1.5C27H18O6·8H2O (ε(BTB)4/3). In Co-ε(BTB)4/3, two tetrabutylammonium (TBA+) cations over the four present in ε(BTB)4/3 are replaced by one [Co(bpy)3]2+ complex. [Co(C10H8N2)3][PMo12O37(OH)3Zn4](C9H3O6)Co(C10H8N2)4(H2O)·16H2O (Co-ε(trim) (bpy)2) is a 1D coordination polymer with two types of CoII-containing complexes, one covalently attached to the 1D chains and the other located in the voids as the counterion. [Ru(C10H8N2)3]4[PMo12O38(OH)2Zn4]2(C9H3O6)2·42H2O (Ru-ε2(trim)2) and [Ru(C10H8N2)3]3[PMo12O37(OH)3Zn4Cl]2(C14H8O4)2·24H2O (Ru-ε2(biphen)2) contain dimeric (εZn)2 units linked by dicarboxylate linkers, and both have [Ru(bpy)3]2+ countercations. Ru-ε2(trim)2 has a 3D framework, while Ru-ε2(biphen)2 is only 2D because of the presence of chloride ions on one-fourth of the ZnII ions. [P(C6H5)4]6[PMo12O37(OH)3Zn4]2(C9H3O6)2·18H2O (PPh4-ε2(trim)2) is isostructural to Ru-ε2(trim)2. These insoluble compounds entrapped in carbon-paste electrodes exhibit electrocatalytic activity for the hydrogen evolution reaction. The effects of their structure and the nature of the counterions on the activity have been studied. For the first time, different POM-based coordination polymers are compared for catalytic H2 production using controlled-potential electrolysis. This study shows that the nature of the countercation has a strong effect on the electrocatalytic activity of the compound.

Published
2017
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27. Divalent Thulium Crown Ether Complexes with Field-Induced Slow Magnetic Relaxation

Author

Grégory Nocton, Olivier Maury, Carole Duboc, Mathieu Xémard, Florian Molton, Olivier Cador, Boris Le Guennic, Marie Cordier, Laboratoire de chimie moléculaire (LCM), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Département de Chimie Moléculaire (DCM), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut des Sciences Chimiques de Rennes (ISCR), 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), Laboratoire de Chimie - UMR5182 (LC), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)-Institut de Chimie du CNRS (INC), CNRS, Ecole polytechnique, IR-RPE CNRS FR3443 network, École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), 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), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
chemistry.chemical_classification, Lanthanide, Spintronics, 010405 organic chemistry, Ligand, chemistry.chemical_element, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, 3. Good health, 0104 chemical sciences, Coordination complex, law.invention, Inorganic Chemistry, Thulium, chemistry, Chemical physics, law, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Physical and Theoretical Chemistry, Ground state, Electron paramagnetic resonance, Crown ether
Abstract

International audience; The tailoring of the coordination chemistry around f-element centers is a crucial step for the development of compounds with slow magnetic relaxation, including single-molecule magnets (SMMs), which have great potential in molecular spintronics and for future quantum computing devices. Lanthanide ions are particularly interesting because the predominant electrostatic model of their bonding allows rationalizing their coordination symmetry. However, to the best of our knowledge, the redox properties of the lanthanides are not taken into account for the design of SMMs, and therefore all SMMs reported to date contain lanthanide ions in their trivalent oxidation state. In this Article, divalent lanthanide compounds presenting field-induced slow magnetic relaxation are reported. The rational design and synthesis of two TmII complexes with the 18-crown-6 ligand are presented along with their emission and EPR properties, which help to probe the desired nature of the ground state, that is, maximizing the anisotropy. The observed magnetic properties demonstrate their slow magnetic relaxation behavior in a moderate external magnetic field.

Published
2019
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28. Reversible electron transfer in organolanthanide chemistry

Author

Maxime Tricoire, Carine Clavaguéra, Arnaud Jaoul, Marie Cordier, Jules Moutet, Grégory Nocton, Laboratoire de chimie moléculaire (LCM), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Laboratoire de Chimie-Physique (LCP), and Université de Cocody

Subjects
Lanthanide, 010405 organic chemistry, Ligand, Chemistry, Crystal structure, 010402 general chemistry, 01 natural sciences, Quantum chemistry, Redox, Article, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Electron transfer, quantum chemistry, Crystallography, Organolanthanide chemistry, [CHIM.COOR]Chemical Sciences/Coordination chemistry, lanthanides, electron density analysis, Isostructural, Palladium, Platinum
Abstract

International audience; This article relates the synthesis and characterization of novel heterobimetallic complexes containing a low-valent lanthanide, a tetradentate redox non-innocent ligand, viz. the 4,5,9,10-tetraazaphenanthrene, taphen ligand and transition metal fragments of PdMe 2 and PtMe 2. The experimental results are supported by a theoretical study. Investigation of their reduction properties allowed the formation of isostructural original heterotrimetallic complexes containing two Cp* 2 Yb fragments and the (taphen)MMe 2 (M = Pd and Pt) motifs. These complexes are stable in non-coordinating solvent such as toluene but decompose in coordinating solvents such as thf. Investigation of the internal electron transfer shows that the taphen ligand behaves as a two-electrons reservoir but is capable of transferring back only one electron in thf. This reversible electron(s) transfer is rare in organolanthanide chemistry and show the potential interest of these complexes in reductive chemistry. Additionally, the trinuclear complexes feature odd X-ray crystal structures in which a deviation of symmetry is observed. The latter observation was studied in depth using quantum chemistry calculations highlighting the role of non-covalent weak interactions.

Published
2019
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29. Lanthanidocenes: Synthesis, Structure, and Bonding of Linear Sandwich Complexes of Lanthanides

Author

Carine Clavaguéra, Marie Cordier, Grégory Nocton, Sébastien Zimmer, Mathieu Xémard, Violaine Goudy, Louis Ricard, Laboratoire de chimie moléculaire (LCM), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Laboratoire de Chimie Physique D'Orsay (LCPO), and Université Paris-Sud - Paris 11 (UP11)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Lanthanide, 010405 organic chemistry, Ligand, Molecular orbital diagram, General Chemistry, 010402 general chemistry, 01 natural sciences, Biochemistry, Catalysis, 0104 chemical sciences, Crystallography, chemistry.chemical_compound, Colloid and Surface Chemistry, Uranocene, chemistry, Ferrocene, Isostructural, [CHIM.OTHE]Chemical Sciences/Other, Isomerization, Conformational isomerism, ComputingMilieux_MISCELLANEOUS
Abstract

The Article presents the synthesis, structure, and bonding of a series of neutral and linear sandwich compounds with the cyclononatetraenyl (Cnt) ligand and divalent lanthanides. These compounds account for the emergence of the lanthanidocene series in reference to the ferrocene and uranocene. The synthetic strategy uses the solubility difference between two conformational isomers of the ligand, as well as the isomerization of the compounds induced by solvent coordination, yielding the isomorphous and isostructural neutral and rigorously linear sandwich complexes. The molecular structures feature a Cnt–Ln–Cnt angle of 180° and a ring size close to the Cnt–Cnt(centroid) distance. A qualitative molecular orbital diagram is provided, in D9d symmetry, and DFT calculations enforce the bonding model.

Published
2018

30. Phenylacetylene and Carbon Dioxide Activation by an Organometallic Samarium Complex

Author

Carlos Alvarez Lamsfus, Simon Karleskind, Violaine Goudy, Grégory Nocton, Mathieu Xémard, Laurent Maron, Marie Cordier, Laboratoire de chimie moléculaire (LCM), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
chemistry.chemical_classification, small molecule activation, 010405 organic chemistry, Chemical structure, Alkyne, chemistry.chemical_element, 010402 general chemistry, 01 natural sciences, Small molecule, lcsh:QD146-197, 3. Good health, 0104 chemical sciences, Inorganic Chemistry, Samarium, chemistry.chemical_compound, Phenylacetylene, chemistry, Carbon dioxide, Polymer chemistry, lcsh:Inorganic chemistry, samarium complexes, C–H activation, C-H activation, [CHIM.OTHE]Chemical Sciences/Other
Abstract

Small molecule activation is a topic of growing importance and the use of low-valent f-elements to perform these reactions is nowadays well established. The complex Cptt2Sm(thf) (1, Cptt = 1,3-(tBu)2Cp) is shown to activate the alkyne C&ndash, H bond of phenylacetylene to form the Cptt2Sm(C&equiv, C&ndash, Ph)(thf) complex. The subsequent reaction of this Sm(III) complex with CO2 leads to the CO2 insertion, yielding a dimeric [Cptt2Sm(O2C&ndash, C&equiv, Ph)]2 complex (2), in which the carbon dioxide has been inserted in the Sm-C bond. Along with the experimental chemical structure analysis, theoretical calculations have been performed in order to rationalize the formation of 1 and 2.

Published
2018
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31. Synthesis and Reactivity of Low-Valent f-Element Iodide Complexes with Neutral Iminophosphorane Ligands

Author

Grégory Nocton, Audrey Auffrant, Karsten Meyer, Frank W. Heinemann, Louis Ricard, Thibault Cheisson, Laboratoire de chimie moléculaire (LCM), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Inorganic Chemistry, Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM) (ICMM), and Friedrich-Alexander Universität Erlangen-Nürnberg (FAU)

Subjects
Steric effects, Ytterbium, chemistry.chemical_classification, 010405 organic chemistry, Ligand, Iodide, chemistry.chemical_element, 010402 general chemistry, 01 natural sciences, Medicinal chemistry, 3. Good health, 0104 chemical sciences, Inorganic Chemistry, chemistry.chemical_compound, Ketyl, chemistry, Pyridine, Benzophenone, Reactivity (chemistry), Physical and Theoretical Chemistry, [CHIM.OTHE]Chemical Sciences/Other, ComputingMilieux_MISCELLANEOUS
Abstract

The coordination and reactivity of simple iodide salts of low-valent f elements [YbI2, SmI2, TmI2, and UI3(THF)4, where THF = tetrahydrofuran] with iminophosphorane (R3P═NR′) ligands are reported. The studied chelates were observed to adapt their geometry and effectively bind divalent ytterbium and samarium centers, as well as the trivalent uranium cation. The reactivity of the ytterbium adducts with benzophenone was found to be dependent on the steric demand of the supporting iminophosphorane ligand. In particular, a rare example of a stable charge-separated ketyl radical species is reported with ytterbium. Additionally, divalent thulium was observed to induce a reductive coupling at the ligand’s central pyridine ring.

Published
2018

32. Correction to Cerium Tetrakis(tropolonate) and Cerium Tetrakis(acethylacetonate) Are Not Diamagnetic but Temperature-Independent Paramagnets

Author

Corwin H. Booth, Grégory Nocton, Robert L. Halbach, Richard A. Andersen, and Laurent Maron

Subjects
010405 organic chemistry, Temperature independent, chemistry.chemical_element, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, Lewis structure, Inorganic Chemistry, Cerium, symbols.namesake, Crystallography, chemistry, symbols, Molecule, Diamagnetism, Singlet state, Physical and Theoretical Chemistry
Abstract

Author(s): Halbach, Robert L; Nocton, Gregory; Booth, Corwin H; Maron, Laurent; Andersen, Richard A | Abstract: Page 7295. In the Summary section of the article, the text should read "The energy of the closed-shell singlet that corresponds to the traditional Lewis structures used to represent these molecules is 400-700 cm-1 above the openshell triplet and singlet." instead of "The energy of the openshell singlet that corresponds to the traditional Lewis structures used to represent these molecules is 400-700 cm-1 above the open-shell triplet."

Published
2018

33. Small molecule activation with divalent samarium triflate: a synergistic effort to cleave O

Author

Mathieu, Xémard, Marie, Cordier, Elisa, Louyriac, Laurent, Maron, Carine, Clavaguéra, and Grégory, Nocton

Abstract

The divalent samarium triflate salt does not react with CO2 or water, but does react with traces of O2 or N2O to form a tetrameric bis-oxo samarium motif. The reaction with O2 is a 4e- reductive cleavage where the electrons are coming from four different samarium centers. This highlights a rare synergistic effect for cleaving O2, which has no precedent in divalent lanthanide complexes. Additionally, the addition of CO2 to the tetrameric bis-oxo intermediate leads to the formation of a tetrameric bis-carbonate samarium triflate. Thus, the concomitant reaction of CO2 with traces of O2 leads to the same bis-carbonate tetrameric assembly.

Published
2018

34. Cerium Tetrakis(tropolonate) and Cerium Tetrakis(acetylacetonate) Are Not Diamagnetic but Temperature-Independent Paramagnets

Author

Grégory Nocton, Corwin H. Booth, Richard A. Andersen, Robert L. Halbach, and Laurent Maron

Subjects
Magnetic moment, 010405 organic chemistry, Chemistry, chemistry.chemical_element, Crystal structure, Annulene, 010402 general chemistry, 01 natural sciences, Magnetic susceptibility, 0104 chemical sciences, Inorganic Chemistry, Paramagnetism, Cerium, Crystallography, Dodecahedron, Diamagnetism, Physical and Theoretical Chemistry
Abstract

A new synthesis of cerium tetrakis(tropolonate), Ce(trop)4, where trop is deprotonated 2-hydroxy-2,4,6-cycloheptatrienone) or Ce(O2C7H5)4, is developed that results in dark-purple crystals whose X-ray crystal structure shows that the geometry of the eight-coordinate compound closely resembles a D2 d dodecahedron, based on shape parameters. The magnetic susceptibility as a function of the temperature (4-300 K) shows that it is a temperature-independent paramagnet, χ = 1.2(3) × 10-4 emu/mol, and the LIII-edge X-ray absorption near-edge structure spectrum shows that the molecule is multiconfigurational, comprised of a f1:f0 configuration mixture in a 50:50 ratio. Ce(acac)4 and Ce(tmtaa)2 (where acac is acetylacetonate and tmtaaH2 is tetramethyldibenzotetraaza[14]annulene) have similar physical properties, as does the solid-state compound CeO2. The concept is advanced that trop-, acac-, tmtaa2-, cot2-, and O2- are redox-active ligands that function as electron donors, rendering the classification of these compounds according to their oxidation numbers misleading because their magnetic susceptibilities, χ, are positive and their effective magnetic moments, μeff, lie in the range of 0.1-0.7 μB at 300 K.

Published
2018

35. η5–η1 Switch in Divalent Phosphaytterbocene Complexes with Neutral Iminophosphoranyl Pincer Ligands: Solid-State Structures and Solution NMR 1JYb–P Coupling Constants

Author

Audrey Auffrant, Grégory Nocton, and Thibault Cheisson

Subjects
Steric effects, Coupling constant, Ytterbium, chemistry.chemical_classification, Stereochemistry, Organic Chemistry, Solid-state, chemistry.chemical_element, Crystal structure, Pincer movement, Divalent, Inorganic Chemistry, Crystallography, chemistry, Yield (chemistry), Physical and Theoretical Chemistry
Abstract

This paper reports the synthesis of a series of complexes based on the bis(pentamethylcyclopentadienyl)ytterbium(II) (1; Cp*2Yb) and bis(tetramethylphospholyl)ytterbium(II) (2; Tmp2Yb) fragments bearing an additional neutral bis(methyliminophosphoranyl)pyridine ligand (L) on which the steric demand is modulated at the phosphorus position (triethyl, LEt; triphenyl, LPh; tricyclohexyl, LCy) to yield the original complexes Cp*2YbLEt (1-LEt), Cp*2YbLPh (1-LPh), Tmp2YbLEt (2-LEt), Tmp2YbLPh (2-LPh), and Tmp2YbLCy (2-LCy), while no reaction occurs between 1 and LCy. The crystal structures of these sterically crowded complexes are reported as well as room-temperature NMR data for all the complexes. The solid-state coordination mode of LR differs depending on the nature of the fragments 1 and 2 and on the steric bulk of LR. The crystal structure of the divalent Tmp2Yb(py)2 (3) is also reported for structural and spectroscopic comparisons. Interestingly, in both 2-LEt and 2-LCy, one of the two Tmp ligands coordina...

Published
2015
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36. Electron localization in a mixed-valence diniobium benzene complex

Author

John Arnold, Grégory Nocton, Nikolas Kaltsoyannis, Thomas L. Gianetti, A. L. David Kilcoyne, Stefan G. Minasian, Tolek Tyliszczak, Robert G. Bergman, David K. Shuh, and Stosh A. Kozimor

Subjects
Valence (chemistry), Chemistry, Inorganic chemistry, General Chemistry, Nuclear magnetic resonance spectroscopy, Electron localization function, law.invention, Delocalized electron, Crystallography, Unpaired electron, law, Molecule, Density functional theory, Electron paramagnetic resonance
Abstract

Reaction of the neutral diniobium benzene complex {[Nb(BDI)N t Bu]2(μ-C6H6)} (BDI = N,N'-diisopropylbenzene-β-diketiminate) with Ag[B(C6F5)4] results in a single electron oxidation to produce a cationic diniobium arene complex, {[Nb(BDI)N t Bu]2(μ-C6H6)}{B(C6F5)4}. Investigation of the solid state and solution phase structure using single-crystal X-ray diffraction, cyclic voltammetry, magnetic susceptibility, and multinuclear NMR spectroscopy indicates that the oxidation results in an asymmetric molecule with two chemically inequivalent Nb atoms. Further characterization using density functional theory (DFT) calculations, UV-visible, Nb L3,2-edge X-ray absorption near-edge structure (XANES), and EPR spectroscopies supports assignment of a diniobium complex, in which one Nb atom carries a single unpaired electron that is not largely delocalized on the second Nb atom. During the oxidative transformation, one electron is removed from the δ-bonding HOMO, which causes a destabilization of the molecule and formation of an asymmetric product. Subsequent reactivity studies indicate that the oxidized product allows access to metal-based chemistry with substrates that did not exhibit reactivity with the starting neutral complex.

Published
2015
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37. Assessment of Density Functionals for Computing Thermodynamic Properties of Lanthanide Complexes

Author

Carine Clavaguéra, Arnaud Jaoul, Grégory Nocton, Laboratoire de chimie moléculaire (LCM), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Laboratoire de Chimie Physique D'Orsay (LCPO), Université Paris-Sud - Paris 11 (UP11)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and ANR-15-CE29-0019,ReDivaLan,Transfert électronique dans les organolanthanides : une approche spectroscopique et théorique(2015)

Subjects
Lanthanide, 010304 chemical physics, Ligand, Phenanthroline, Thermodynamics, Electronic structure, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, electron transfer, electronic structure, 01 natural sciences, Quantum chemistry, Atomic and Molecular Physics, and Optics, 0104 chemical sciences, chemistry.chemical_compound, Electron transfer, chemistry, Atomic orbital, Computational chemistry, 0103 physical sciences, density functional calculations, Density functional theory, lanthanides, Physical and Theoretical Chemistry, ELF (electron localization function)
Abstract

International audience; The equilibrium between the radical phenanthroline complex Cp*2 Sm(phen) and the coupling product (Cp*2 Sm(phen))2 has been investigated based on quantum chemistry calculations. Topological analyses pointed out that the C-C bond created has a partial covalent character, explaining why both the monomeric and the dimeric forms exist in equilibrium. A large variety of density functionals have been tested to reproduce experimental thermodynamic data for this equilibrium. Finally, the PBE0-D3 and M06-2X functionals lead to a good evaluation of the energies and enable a correct description of the ligand to metal charge transfer, both in the 4f and 5d metal orbitals.

Published
2017
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38. Tuning the Stability of Pd(IV) Intermediates Using a Redox Non-innocent Ligand Combined with an Organolanthanide Fragment

Author

Violaine Goudy, Arnaud Jaoul, Carine Clavaguéra, Grégory Nocton, Marie Cordier, Laboratoire de chimie moléculaire (LCM), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Laboratoire de Chimie Physique D'Orsay (LCPO), Université Paris-Sud - Paris 11 (UP11)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and ANR-15-CE29-0019,ReDivaLan,Transfert électronique dans les organolanthanides : une approche spectroscopique et théorique(2015)

Subjects
chemistry.chemical_classification, 010405 organic chemistry, Stereochemistry, Ligand, Communication, chemistry.chemical_element, General Chemistry, Electronic structure, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, Photochemistry, 01 natural sciences, Biochemistry, Redox, Oxidative addition, Catalysis, Non-innocent ligand, 3. Good health, 0104 chemical sciences, Divalent, Colloid and Surface Chemistry, chemistry, Moiety, Palladium
Abstract

International audience; The unique combination of a divalent organolanthanide fragment, Cp*2Yb, with bipyrimidine (bipym) and a palladium bis-alkyl fragment, PdMe2, allows the rapid formation and stabilization of a PdIV tris-alkyl moiety after oxidative addition with MeI. The crucial role of the organolanthanide fragment is demonstrated by the substitution of bipym by the 4,5,9,10-tetraazaphenanthrene ligand, which drastically modifies the electronic structure and tunes the stability of the PdIV species.

Published
2017
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39. Electronic Structures of Mono-Oxidized Copper and Nickel Phosphasalen Complexes

Author

Irene Mustieles Marín, Thibault Cheisson, Rohit Singh-Chauhan, Grégory Nocton, Audrey Auffrant, Marie Cordier, Christian Herrero, Carine Clavaguéra, Université Paris-Saclay, Laboratoire de chimie moléculaire (LCM), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Laboratoire de Chimie Physique D'Orsay (LCPO), Université Paris-Sud - Paris 11 (UP11)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), ANR-13-JS07-0001,PsalenOx,Oxydation de complexes à ligand phosphasalen(2013), and École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Substituent, chemistry.chemical_element, Electronic structure, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, Catalysis, law.invention, Metal, chemistry.chemical_compound, nickel, Oxidation state, law, Electron paramagnetic resonance, 010405 organic chemistry, Ligand, Organic Chemistry, non-innocent ligands, General Chemistry, electronic structure, Non-innocent ligand, 0104 chemical sciences, Nickel, Crystallography, chemistry, visual_art, copper, visual_art.visual_art_medium, phosphasalen
Abstract

International audience; Non‐innocent ligands render the determination of the electronic structure in metal complexes difficult. As such, a combination of experimental techniques and quantum chemistry are required to correctly elucidate them. This paper deals with the one‐electron oxidation of copper(II) and nickel(II) complexes featuring a phosphasalen ligand (Psalen), which differs from salen analogues by the presence of iminophosphorane groups (P=N) instead of imines. Various experimental techniques (X‐ray diffraction, cyclic voltammetry, NMR, EPR, and UV/Vis spectroscopies, and magnetic measurements) as well as quantum chemical calculations were used to define the electronic structure of the oxidized complexes. These can be modified by a small change in the ligand structure, that is, the replacement of a tert‐butyl group by a methoxy on the phenoxide ring. The different techniques have allowed quantifying the amount of spin density located on the metal center and on the Psalen ligands. All complexes were found to possess a multi‐configurational ground state, in which the ratio of the +II versus +III oxidation state of the metal center, and therefore the phenolate versus phenoxyl radical ligand character, varies upon the substituents. The tert‐butyl group favors a strong localization on the metal center whereas with the methoxy group the metallic configurations decrease and the ligand configurations increase. The importance of the geometrical considerations compared with the electronic substituent effect is highlighted by the differences observed between the solid‐state (EPR, magnetic measurements) and solution characterizations (EPR and NMR data).

Published
2017
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40. Back Cover: Divalent Thulium Triflate: A Structural and Spectroscopic Study (Angew. Chem. Int. Ed. 15/2017)

Author

Marie Cordier, Florian Molton, Olivier Maury, Carole Duboc, Carine Clavaguéra, Grégory Nocton, Olivier Cador, Arnaud Jaoul, Boris Le Guennic, Mathieu Xémard, Laboratoire de chimie moléculaire (LCM), École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Département de Chimie Moléculaire - Chimie Inorganique Redox Biomimétique (DCM - CIRE ), Département de Chimie Moléculaire (DCM), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université de Bordeaux (UB), Institut des Sciences Chimiques de Rennes (ISCR), 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), Laboratoire de Chimie - UMR5182 (LC), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)-Institut de Chimie du CNRS (INC), Laboratoire de Chimie Physique D'Orsay (LCPO), Université Paris-Sud - Paris 11 (UP11)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Département de Chimie Moléculaire - Chimie Inorganique Redox (DCM - CIRE ), Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), 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), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)

Subjects
chemistry.chemical_classification, Lanthanide, 010405 organic chemistry, Inorganic chemistry, chemistry.chemical_element, General Chemistry, 01 natural sciences, Catalysis, 0104 chemical sciences, Divalent, law.invention, Thulium, chemistry, law, Polymer chemistry, [CHIM]Chemical Sciences, Cover (algebra), Electron paramagnetic resonance, Trifluoromethanesulfonate, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2017
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41. A Tetracoordinated Phosphasalen Nickel(III) Complex

Author

Xavier F. Le Goff, Louis Ricard, Thi-Phuong-Anh Cao, Audrey Auffrant, Grégory Nocton, Laboratoire Hétéroéléments et Coordination (DCPH), and École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Diffraction, Inorganic chemistry, Imine, Salt (chemistry), chemistry.chemical_element, 010402 general chemistry, 01 natural sciences, Catalysis, law.invention, Metal, chemistry.chemical_compound, law, Spectroscopy, Electron paramagnetic resonance, ComputingMilieux_MISCELLANEOUS, chemistry.chemical_classification, 010405 organic chemistry, Ligand, General Medicine, General Chemistry, 0104 chemical sciences, Crystallography, Nickel, chemistry, visual_art, visual_art.visual_art_medium, [CHIM.OTHE]Chemical Sciences/Other
Abstract

The oxidation of a Ni(II) complex bearing a tetradentate phosphasalen ligand, which differs from salen by the presence of an iminophosphorane (PN) in place of an imine unit, was easily achieved by addition of a silver salt. The site of this oxidation was investigated with a combination of techniques (NMR, EPR, UV/Vis spectroscopy, X-ray diffraction, magnetic measurements) as well as DFT calculations. All data are in agreement with a high-valent Ni(III) center concentrating the spin density. This markedly differs from precedents in the salen series for which oxidation on the metal was only observed at low temperature or in the presence of additional ligands or anions. Therefore, thanks to the good electron-donating properties of the phosphasalen ligand, [Ni(Psalen)](+) represents a rare example of a tetracoordinated high-valent nickel complex in presence of a phenoxide ligand.

Published
2013
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42. Influence of the Torsion Angle in 3,3′-Dimethyl-2,2′-bipyridine on the Intermediate Valence of Yb in (C5Me5)2Yb(3,3′-Me2-bipy)

Author

Grégory Nocton, Richard A. Andersen, Laurent Maron, Corwin H. Booth, Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, Laboratoire Hétéroéléments et Coordination (DCPH), École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), 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), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Valence (chemistry), 010405 organic chemistry, Chemistry, Organic Chemistry, Crystal structure, Dihedral angle, 010402 general chemistry, 01 natural sciences, 2,2'-Bipyridine, 0104 chemical sciences, Inorganic Chemistry, Bipyridine, chemistry.chemical_compound, Crystallography, Computational chemistry, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Singlet state, Physical and Theoretical Chemistry, Triplet state, Ground state
Abstract

International audience; The synthesis and X-ray crystal structures of Cp*2Yb(3,3′-Me2bipy) and [Cp*2Yb(3,3′-Me2bipy)][Cp*2YbCl1.6I0.4]*CH2Cl2 are described. In both complexes, the NCCN torsion angles are approximately 40°. The temperature-independent value of nf of 0.17 shows that the valence of ytterbium in the neutral adduct is multiconfigurational, in reasonable agreement with a CASSCF calculation that yields a nf value of 0.27; that is, the two configurations in the wave function are f13(π*1)1 and f14(π*1)0 in a ratio of 0.27:0.73, respectively, and the open-shell singlet lies 0.28 eV below the triplet state (nf accounts for f-hole occupancy; that is, nf = 1 when the configuration is f13 and nf = 0 when the configuration is f14). A correlation is outlined between the value of nf and the individual ytterbocene and bipyridine fragments such that, as the reduction potentials of the ytterbocene cation and the free x,x′-R2-bipy ligands approach each other, the value of nf and therefore the f13:f14 ratio reaches a maximum; conversely, the ratio is minimized as the disparity increases.

Published
2013
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43. Synthesis and Characterization of 1,1′-Diphosphaplumbocenes: Oxidative Ligand Transfer Reactions with Divalent Thulium Complexes

Author

Aurélien Momin, Louis Ricard, Agathe Martinez, Grégory Nocton, Dominique Harakat, Xavier F. Le Goff, Florian Jaroschik, Institut de Chimie Moléculaire de Reims - UMR 7312 (ICMR), SFR Condorcet, Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)-Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)-SFR CAP Santé (Champagne-Ardenne Picardie Santé), Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Université de Reims Champagne-Ardenne (URCA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de chimie moléculaire (LCM), and École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Lanthanide, chemistry.chemical_classification, 010405 organic chemistry, Chemistry, Ligand, Stereochemistry, [CHIM.ORGA]Chemical Sciences/Organic chemistry, Organic Chemistry, chemistry.chemical_element, Nuclear magnetic resonance spectroscopy, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, Divalent, Inorganic Chemistry, NMR spectra database, Crystallography, Thulium, Cyclopentadienyl complex, Proton NMR, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Physical and Theoretical Chemistry
Abstract

International audience; The new 1,1′-diphosphaplumbocenes Pb(Dtp)2(Dtp = 2,5-di-tert-butyl-3,4-dimethylphospholyl) and Pb(Dsp)2(Dsp = 2,5-ditrimethylsilyl-3,4-dimethylphospholyl) have beensynthesized and characterized by multinuclear NMR spectroscopy.207Pb NMR spectra of both complexes, as well as for theknown complex Pb(Htp)2 (Htp = 2,5-di-tert-butylphospholyl),show that the phospholyl ligands lead to an important downfieldshift compared with that of cyclopentadienyl based plumbocenes.X-ray diffraction studies of the Pb(Dtp)2 complex revealed astructure with two slightly bent η5-bound ligands. This complexwas employed in the oxidative ligand transfer reaction with bulkydivalent thulium complexes. In the case of Tm(Dtp)2, the firstexample of a monomeric trivalent tris(phospholyl)lanthanidecomplex Tm(Dtp)3 was obtained. X-ray diffraction studies andlow-temperature 1H NMR studies show the η1 coordination mode of the third Dtp ligand. In contrast, oxidation of Tm(Cpttt)2(Cpttt is for tris-tert-butylcyclopentadienyl) led presumably to the formation of the ion pair complex [Tm(Cpttt)2][Dtp], in whichno interaction between the free Dtp ligand and Tm was observed, as shown by variable temperature 1H and 31P NMR studies.The new trivalent complexes could be reduced back to the original divalent complexes with potassium graphite.

Published
2016
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44. Self-Assembly of Polyoxo Clusters and Extended Frameworks by Controlled Hydrolysis of Low-Valent Uranium

Author

Fabien Burdet, Grégory Nocton, Marinella Mazzanti, Jacques Pécaut, Reconnaissance Ionique et Chimie de Coordination (RICC), 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)-Institut de Chimie du CNRS (INC)-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)-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), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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
Web of science, Chemistry, 010405 organic chemistry, Inorganic chemistry, chemistry.chemical_element, General Chemistry, Actinide, General Medicine, Uranium, 010402 general chemistry, 01 natural sciences, Catalysis, 0104 chemical sciences, Hydrolysis, [CHIM]Chemical Sciences, Self-assembly, ComputingMilieux_MISCELLANEOUS
Abstract

Reference EPFL-ARTICLE-203035doi:10.1002/anie.200702374View record in Web of Science Record created on 2014-11-07, modified on 2016-08-10

Published
2007
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45. Lanthanide(II) Complexes Supported by N,O-Donor Tripodal Ligands: Synthesis, Structure, and Ligand-Dependent Redox Behavior

Author

Grégory Nocton, Julie Andrez, Marinella Mazzanti, Guelay Bozoklu, Rosario Scopelliti, Lionel Dubois, Jacques Pécaut, Institute of Chemical Sciences and Engineering, SB, GGEC Station 6 (EPFL), Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratoire de Chimie Inorganique et Biologique, Laboratoire de chimie moléculaire (LCM), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Chimie Interface Biologie pour l’Environnement, la Santé et la Toxicologie [2017-2019] (CIBEST [2017-2019]), SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé (SYMMES), 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)-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), Conception d’Architectures Moléculaires et Processus Electroniques [2017-2019] (CAMPE [2017-2019]), Reconnaissance Ionique et Chimie de Coordination (RICC), 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 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), Swiss National Science Foundation, EPFL, Institut de Chimie du CNRS (INC)-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)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-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)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Lanthanide, Ligand, ligands, Organic Chemistry, Inorganic chemistry, chemistry.chemical_element, reduction, ytterbium, General Chemistry, Crystal structure, Medicinal chemistry, Catalysis, Dimethoxyethane, chemistry.chemical_compound, chemistry, [CHIM]Chemical Sciences, Amine gas treating, Reactivity (chemistry), lanthanides, Homoleptic, Europium, europium, ComputingMilieux_MISCELLANEOUS
Abstract

International audience; The preparation and characterization of a series of complexes of the Yb and Eu cations in the oxidation state II and III with the tetradentate N,O-donor tripodal ligands (tris(2-pyridylmethyl)amine (TPA), BPA(-) (HBPA=bis(2-pyridylmethyl)(2-hydroxybenzyl)amine), BPPA(-) (HBPPA=bis(2-pyridylmethyl)(3.5-di-tert-butyl-2-hydroxybenzyl)amine), and MPA(2-) (H(2)MPA=(2-pyridylmethyl)bis(3.5-di-tert-butyl-2-hydroxybenzyl)amine) is reported. The X-ray crystal structures of the heteroleptic Ln(2+) complexes [Ln(TPA)I-2] (Ln=Eu, Yb) and [Yb(BPA)I(CH3CN)](2), of the Ln(2+) homoleptic [Ln(TPA)(2)]I-2 (Ln=Sm, Eu, Yb) and [Eu(BPA)(2)] complexes, and of the Ln(3+) [Eu(BPPA)(2)]OTf and [Yb(MPA)(2)K(dme)(2)] (dme=dimethoxyethane) complexes have been determined. Cyclic voltammetry studies carried out on the bis-ligand complexes of Eu3+ and Yb3+ show that the metal center reduction occurs at significantly lower potentials for the BPA(-) ligand as compared with the TPA ligand. This suggests that the more electron-rich character of the BPA(-) ligand results in a higher reducing character of the lanthanide complexes of BPA(-) compared with those of TPA. The important differences in the stability and reactivity of the investigated complexes are probably due to the observed difference in redox potential. Preliminary reactivity studies show that whereas the bis-TPA complexes of Eu2+ and Yb2+ do not show any reactivity with heteroallenes, the [Eu(BPA)(2)] complex reduces CS2 to afford the first example of a lanthanide trithiocarbonate complex.

Published
2015
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46. Reversible C-C coupling in phenanthroline complexes of divalent samarium and thulium

Author

Louis Ricard, Grégory Nocton, Laboratoire de chimie moléculaire (LCM), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), and Tard, Cédric

Subjects
Phenanthroline, chemistry.chemical_element, 010402 general chemistry, Photochemistry, 01 natural sciences, Catalysis, Divalent, Adduct, C c coupling, chemistry.chemical_compound, Materials Chemistry, ComputingMilieux_MISCELLANEOUS, chemistry.chemical_classification, 010405 organic chemistry, Ligand, Metals and Alloys, General Chemistry, 3. Good health, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Samarium, Crystallography, Thulium, chemistry, [CHIM.OTHE] Chemical Sciences/Other, Yield (chemistry), Ceramics and Composites, [CHIM.OTHE]Chemical Sciences/Other
Abstract

The reaction of a series of organolanthanide fragments of samarium and thulium with phenanthroline is reported. All adducts couple in the 4-position of the phenanthroline ligand to yield the 4–4′ dimers when they crystallize. The analysis of the solution structure revealed a thermally reversible C–C coupling in all cases.

Published
2015

47. Geometry Flexibility of Copper Iodide Clusters: Variability in Luminescence Thermochromism

Author

Aurélie Berhault, Alain Garcia, Charlotte Martineau, Alexandre Fargues, Julien Trébosc, Sandrine Perruchas, Xavier F. Le Goff, Quentin Benito, Grégory Nocton, Samia Kahlal, Jean-Pierre Boilot, Thierry Gacoin, Jean-Yves Saillard, Laboratoire de physique de la matière condensée (LPMC), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de chimie moléculaire (LCM), École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université européenne de Bretagne - European University of Brittany (UEB), 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), Institut Lavoisier de Versailles (ILV), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Lille, Sciences et Technologies, 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), The authors thank the CNRS and the Ecole Polytechnique for funding. J.Y.S. thanks the IUF for its support. Financial support from the TGIR-RMN-THC Fr3050 CNRS for conducting the research is gratefully acknowledged. C.M. is grateful for financial support from Contract No. ANR-12-JS08-0008., Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université de Bordeaux (UB), 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), and 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

Subjects
Models, Molecular, Luminescence, Magnetic Resonance Spectroscopy, Phosphines, Iodide, Geometry, Crystallography, X-Ray, Ligands, Inorganic Chemistry, chemistry.chemical_compound, Cluster (physics), Organometallic Compounds, Molecule, [CHIM]Chemical Sciences, Molecular orbital, Physical and Theoretical Chemistry, chemistry.chemical_classification, Thermochromism, Molecular Structure, Temperature, [CHIM.MATE]Chemical Sciences/Material chemistry, Iodides, chemistry, Cubane, Quantum Theory, Thermodynamics, Density functional theory, Copper
Abstract

International audience; An original copper(I) iodide cluster of novel geometry obtained by using a diphosphine ligand is reported and is formulated [Cu6I6(PPh2(CH2)3PPh2)3] (1). Interestingly, this sort of “eared cubane” cluster based on the [Cu6I6] inorganic core can be viewed as a combination of the two known [Cu4I4] units, namely, the cubane and the open-chair isomeric geometries. The synthesis, structural and photophysical characterisations, as well as theoretical study of this copper iodide along with the derived cubane (3) and open-chair (2) [Cu4I4(PPh3)4] forms, were investigated. A new polymorph of the cubane [Cu4I4(PPh3)4] cluster is indeed presented (3). The structural differences of the clusters were analyzed by solid-state nuclear magnetic resonance spectroscopy. Luminescence properties of the three clusters were studied in detail as a function of the temperature showing reversible luminescence thermochromism for 1 with an intense orange emission at room temperature. This behavior presents different feature compared to the cubane cluster and completely contrasts with the open isomer, which is almost nonemissive at room temperature. Indeed, the thermochromism of 1 differs by a concomitant increase of the two emission bands by lowering the temperature, in contrast to an equilibrium phenomenon for 3. The luminescence properties of 2 are very different by exhibiting only one single band when cooled. To rationalize the different optical properties observed, density functional theory calculations were performed for the three clusters giving straightforward explanation for the different luminescence thermochromism observed, which is attributed to different contributions of the ligands to the molecular orbitals. Comparison of 3 with its [Cu4I4(PPh3)4] cubane polymorphs highlights the sensibility of the emission properties to the cuprophilic interactions.

Published
2015
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48. Mechanochromic luminescence of copper iodide clusters

Author

Alain Garcia, Quentin Benito, Thierry Gacoin, Isabelle Maurin, Alexandre Fargues, Jean-Pierre Boilot, Charlotte Martineau, Grégory Nocton, Sandrine Perruchas, Thibault Cheisson, Laboratoire de physique de la matière condensée (LPMC), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Hétéroéléments et Coordination (DCPH), École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université de Bordeaux (UB), Institut Lavoisier de Versailles (ILV), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Thermochromism, Mechanochromic luminescence, Organic Chemistry, chemistry.chemical_element, General Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, Photochemistry, Copper, Catalysis, Crystal, Polymorphism (materials science), chemistry, X-ray crystallography, Cluster (physics), Luminescence
Abstract

International audience; Luminescent mechanochromic materials are particularly appealing for the development of stimuli-responsive materials. Establishing the mechanism responsible for the mechanochromism is always an issue owing to the difficulty in characterizing the ground phase. Herein, the study of real crystalline polymorphs of a mechanochromic and thermochromic luminescent copper iodide cluster permits us to clearly establish the mechanism involved. The local disruption of the crystal packing induces changes in the cluster geometry and in particular the modification of the cuprophilic interactions, which consequently modify the emissive states. This study constitutes a step further toward the understanding of the mechanism involved in the mechanochromic luminescent properties of multimetallic coordination complexes.

Published
2015

50. Carbon-Hydrogen Bond Breaking and Making in the Open-Shell Singlet Molecule Cp* 2 Yb(4,7-Me 2 phen)

Author

Corwin H. Booth, Richard A. Andersen, Louis Ricard, Laurent Maron, Grégory Nocton, Laboratoire de chimie moléculaire (LCM), École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Chemical Sciences Division [LBNL Berkeley] (CSD), 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)-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), Berkeley University of California (UC BERKELEY), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), University of California [Berkeley] (UC Berkeley), and University of California (UC)

Subjects
Phenanthroline, Organic Chemistry, Photochemistry, 3. Good health, Adduct, Inorganic Chemistry, chemistry.chemical_compound, Crystallography, chemistry, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Singlet state, Physical and Theoretical Chemistry, Triplet state, Ground state, Open shell, HOMO/LUMO, Methyl group
Abstract

International audience; he adducts formed between the 4,7-Me2-, 3,4,7,8-Me4-, and 3,4,5,6,7,8-Me6-phenanthroline ligands and Cp*2Yb are shown to have open-shell singlet ground states by magnetic susceptibility and LIII-edge XANES spectroscopy. Variable-temperature XANES data show that two singlet states are occupied in each adduct that are fit to a Boltzmann distribution for which ΔH = 5.75 kJ mol–1 for the 4,7-Me2phen adduct. The results of a CASSCF calculation for the 4,7-Me2phen adduct indicates that three open-shell singlet states, SS1–SS3, lie 0.44, 0.06. and 0.02 eV, respectively, below the triplet state. These results are in dramatic contrast to those acquired for the phenanthroline and 5,6-Me2phen adducts, which are ground state triplets ( J. Am. Chem. Soc. 2014, 136, 8626). A model that accounts for these differences is traced to the relative energies of the LUMO and LUMO+1 orbitals that depend on the position the methyl group occupies in the phenanthroline ligand. The model also accounts for the difference in reactivities of Cp*2Yb(3,8-Me2phen) and Cp*2Yb(4,7-Me2phen); the former forms a σ C–C bond between C(4)C(4′), and the latter undergoes C–H bond cleavage at the methyl group on C(4) and leads to two products that cocrystallize: Cp*2Yb(4-(CH2),7-Mephen), which has lost a hydrogen atom, and Cp*2Yb(4,7-Me2-4H-phen), which has gained a hydrogen atom.

Published
2014
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