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4. Electronic Structures of Mono-Oxidized Copper and Nickel Phosphasalen Complexes

Author

Xemard, Mathieu, Goudy, Violaine, Braun, Augustin, Tricoire, Maxime, Ricard, Louis, Castro, Ludovic, Louyriac, Elisa, Kefalidis, Christos, Maron, Laurent, Mustieles Marín, Irene, Cheisson, Thibault, Singh-Chauhan, Rohit, Herrero, Christian, Cordier, Marie, Clavaguera, Carine, Nocton, Grégory, Auffrant, Audrey, Laboratoire de chimie moléculaire (LCM), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-École polytechnique (X), Diversity-centric Software Engineering (DiverSe), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-LANGAGE ET GÉNIE LOGICIEL (IRISA-D4), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), 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)-Université de Rennes (UNIV-RENNES)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-CentraleSupélec-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Université de Rennes (UNIV-RENNES)-CentraleSupélec-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Rennes (ENS Rennes)-Télécom Bretagne-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-CentraleSupélec, Laboratoire Hétéroéléments et Coordination (DCPH), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Conception d’Architectures Moléculaires et Processus Electroniques (CAMPE), SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé (SYMMES), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-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 (UGA)-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), 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)-Université Toulouse III - Paul Sabatier (UPS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Saclay, Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des mécanismes réactionnels (DCMR), and École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[CHIM.INOR]Chemical Sciences/Inorganic chemistry, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2017

5. Formation of Methane versus Benzene in the Reactions of (C5Me5)(2)Th(CH3)(2) with [CH3PPh3]X (X=Cl, Br, I) Yielding Thorium-Carbene or Thorium-Ylide Complexes

Author

Rungthanaphatsophon, Pokpong, Bathelier, Adrien, Castro, Ludovic, Behrle, Andrew C., Barnes, Charles L., Maron, Laurent, Walensky, Justin R., Department of Chemistry, Missouri University of Science and Technology, University of Missouri [Columbia] (Mizzou), University of Missouri System-University of Missouri System, Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)

Subjects
carbenes, [PHYS]Physics [physics], ylides, multiple bonding, [CHIM]Chemical Sciences, organometallics, thorium
Abstract

bibtex: ISI:000412189700021 bibtex\location:'POSTFACH 101161, 69451 WEINHEIM, GERMANY',publisher:'WILEY-V C H VERLAG GMBH',type:'Article',affiliation:'Walensky, JR (Reprint Author), Univ Missouri, Dept Chem, Columbia, MO 65211 USA. Maron, L (Reprint Author), Univ Toulouse, 135 Ave Rangueil, F-31077 Toulouse, France. Maron, L (Reprint Author), LPCNO, CNRS, INSA, UPS,UMR,UMR 5215, 135 Ave Rangueil, F-31077 Toulouse, France. Rungthanaphatsophon, Pokpong; Bathelier, Adrien; Barnes, Charles L.; Walensky, Justin R., Univ Missouri, Dept Chem, Columbia, MO 65211 USA. Bathelier, Adrien; Castro, Ludovic; Maron, Laurent, Univ Toulouse, 135 Ave Rangueil, F-31077 Toulouse, France. Bathelier, Adrien; Castro, Ludovic; Maron, Laurent, LPCNO, CNRS, INSA, UPS,UMR,UMR 5215, 135 Ave Rangueil, F-31077 Toulouse, France.','author-email':'laurent.maron@irsamc.ups-tlse.fr walenskyj@missouri.edu',da:'2018-12-05','doc-delivery-number':'FI7PR',eissn:'1521-3773','funding-acknowledgement':'U.S. Department of Energy, Office of Science, Early Career Research Program [DE-SC-0014174]; Humboldt Foundation; Chinese Academy of Science; CalMip','funding-text':'J.R.W. gratefully acknowledges support for this work from the U.S. Department of Energy, Office of Science, Early Career Research Program under Award Number DE-SC-0014174. L.M. is member of the Instiut Universitaire de France. The Humboldt Foundation, the Chinese Academy of Science and CalMip is acknowledged for either financial support or computing time.','journal-iso':'Angew. Chem.-Int. Edit.','keywords-plus':'CARBON MULTIPLE BOND; MOLECULAR-STRUCTURE; METALLA-ALLENES; URANIUM COMPLEX; TRANS-INFLUENCE; U-IV=C; REACTIVITY; LIGAND; CHEMISTRY; PH2PNSIME3','number-of-cited-references':'42',oa:'Bronze','orcid-numbers':'Walensky, Justin/0000-0003-0221-2675','research-areas':'Chemistry','times-cited':'5','unique-id':'ISI:000412189700021','usage-count-last-180-days':'0','usage-count-since-2013':'9','web-of-science-categories':'Chemistry, Multidisciplinary'\; International audience; The reaction of (C5Me5)(2)Th(CH3)(2) with the phosphonium salts [CH3PPh3]X (X=Cl, Br, I) was investigated. When X=Br and I, two equivalents of methane are liberated to afford (C5Me5)(2)Th[CHPPh3]X, rare terminal phosphorano-stabilized carbenes with thorium. These complexes feature the shortest thorium-carbon bonds (approximate to 2.30 angstrom) reported to date, and electronic structure calculations show some degree of multiple bonding. However, when X = Cl, only one equivalent of methane is lost with concomitant formation of benzene from an unstable phosphorus(V) intermediate, yielding (C5Me5)(2)Th[kappa(2)-(C,C')-(CH2)(CH2)PPh2]Cl. Density functional theory (DFT) investigations of the reaction energy profiles for [CH3PPh3]X, X = Cl and I showed that in the case of iodide, thermodynamics prevents the production of benzene and favors formation of the carbene.

Published
2017
Full Text
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6. Reductive Disproportionation of CO2 with Bulky Divalent Samarium Complexes

Author

Xemard, Mathieu, Goudy, Violaine, Braun, Augustin, Tricoire, Maxime, Cordier, Marie, Ricard, Louis, Castro, Ludovic, Louyriac, Elisa, Kefalidis, Christos E., Clavaguera, Carine, Maron, Laurent, Nocton, Grégory, 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), 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), 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)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], [CHIM]Chemical Sciences
Abstract

bibtex: ISI:000418109700020 bibtex\location:'1155 16TH ST, NW, WASHINGTON, DC 20036 USA',publisher:'AMER CHEMICAL SOC',type:'Article',affiliation:'Nocton, G (Reprint Author), Univ Paris Saclay, CNRS, Ecole Polytech, LCM, Route Saclay, F-91128 Palaiseau, France. Xemard, Mathieu; Goudy, Violaine; Braun, Augustin; Tricoire, Maxime; Cordier, Marie; Ricard, Louis; Nocton, Gregory, Univ Paris Saclay, CNRS, Ecole Polytech, LCM, Route Saclay, F-91128 Palaiseau, France. Castro, Ludovic; Louyriac, Elisa; Kefalidis, Christos E.; Maron, Laurent, Univ Toulouse, CNRS, UMR 5215, LPCNO,INSA,UPS, Toulouse, France. Clavaguera, Carine, Univ Pari Saclay, Univ Paris Sud, CNRS, Lab Chim Phys, 15 Ave Jean Perrin, F-91405 Orsay, France.','author-email':'greg.nocton@polytechnique.edu',da:'2018-12-05','doc-delivery-number':'FQ1IG',eissn:'1520-6041','funding-acknowledgement':'French National Agency [ANR-15-CE29-0019]; CNRS; Ecole polytechnique; DGA','funding-text':'This project was financed by the French National Agency with grant number ANR-15-CE29-0019. We thank the CNRS and Ecole polytechnique for funding. M.X. is grateful to the DGA for funding. L.M. is a member of the Institut Universitaire de France.','journal-iso':'Organometallics','keywords-plus':'BIPYRIDYL THORIUM METALLOCENE; SOLID-STATE STRUCTURES; RARE-EARTH-ELEMENTS; CARBON-MONOXIDE; ORGANOMETALLIC COMPOUNDS; LANTHANIDE COMPLEXES; CRYSTAL-STRUCTURE; ACTIVATION; REACTIVITY; COORDINATION','number-of-cited-references':'65','orcid-numbers':'Clavaguera, Carine/0000-0001-5531-2333','research-areas':'Chemistry','researcherid-numbers':'Clavaguera, Carine/A-1433-2013 Nocton, Greg/D-4435-2009','times-cited':'3','unique-id':'ISI:000418109700020','usage-count-last-180-days':'7','usage-count-since-2013':'14','web-of-science-categories':'Chemistry, Inorganic & Nuclear; Chemistry, Organic'\; The base-free divalent samarium complex (Cp2Sm)-Sm-tt (1; Cp-tt = 1,3-(Bu-t)(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 degrees C under reduced pressure. The dissolution of 1 in thf and pyridine solution leads to the solvent adducts (Ce2Sm)-Sm-tt(thf)(2) (3) and (Ce2Sm)-Sm-tt(py) (4), respectively, while drying 3 under reduced pressure yields (CpSm)-Sm-tt(thf) (5). The reaction of CO2 with the base-free divalent samarium complexes (Cp2Sm)-Sm-tt (1) and (Cp2Sm)-Sm-ttt (2; Cp-ttt =1,2,4-(Bu-t)(3)(C5H2)) leads to the clean formation of bridged carbonate samarium dimers [(Cr2Sm)-Sm-ttt](2)(mu-CO3) (7) and [(Cp2Sm)-Sm-tt](2)(mu-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*Sm-2(thf)(2) complex. Otherwise, the reaction with CO does not proceed with the bulky complexes, while traces of O-2 have led to the formation of the original bridged peroxo samarium dimer [Cp(2)(ttt)sm](2)(mu-O-2) (6). The mechanism for these reactions is studied herein by experiments and also by theoretical computations. The key result is that the different pathways are rather close in energy, which also explains why the nature of the final product, if only one is present, is difficult to predict a priori in this chemistry.

Published
2017

7. Concomitant Carboxylate and Oxalate Formation From the Activation of CO 2 by a Thorium(III) Complex

Author

Formanuik, Alasdair, Ortu, Fabrizio, Inman, Christopher, Kerridge, Andrew, Castro, Ludovic, Maron, Laurent, Mills, David, School of Chemistry [Manchester], University of Manchester [Manchester], Department of Chemistry, School of Life Sciences, University of Sussex, Univ Lancaster, Dept Chem, Lancaster LA1 4YB, England, Laboratoire de physique et chimie des nano-objets (LPCNO), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), University of Sussex, 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
[CHIM]Chemical Sciences
Abstract

International audience; Improving our comprehension of diverse CO2 activation pathways is of vital importance for the widespread future utilization of this abundant greenhouse gas. CO2 activation by uranium(III) complexes is now relatively well understood, with oxo/carbonate formation predominating as CO2 is readily reduced to CO, but isolated thorium(III) CO2 activation is unprecedented. We show that the thorium(III) complex, [Th(Cp′′)3] (1, Cp′′={C5H3(SiMe3)2‐1,3}), reacts with CO2 to give the mixed oxalate‐carboxylate thorium(IV) complex [{Th(Cp′′)2[κ2‐O2C{C5H3‐3,3′‐(SiMe3)2}]}2(μ‐κ2:κ2‐C2O4)] (3). The concomitant formation of oxalate and carboxylate is unique for CO2 activation, as in previous examples either reduction or insertion is favored to yield a single product. Therefore, thorium(III) CO2 activation can differ from better understood uranium(III) chemistry.

Published
2016

8. Concomitant Carboxylate and Oxalate Formation From the Activation of CO2 by a Thorium(III) Complex

Author

Formanuik, Alasdair, Ortu, Fabrizio, Inman, Christopher J., Kerridge, Andrew, Castro, Ludovic, and Mills, David

Abstract

Improving our comprehension of diverse CO2 activation pathways is of vital importance for the widespread future utilization of an abundant greenhouse gas. CO2 activation by uranium(III) complexes is now relatively well understood, with oxo/carbonate formation predominating as CO2 is readily reduced to CO, but isolated thorium(III) CO2 activation is unprecedented. We show that the thorium(III) complex, [Th(Cp′′)3] (1, Cp′′ = {C5H3(SiMe3)2-1,3}), reacts with CO2 to give the mixed oxalate-carboxylate thorium(IV) complex [{Th(Cp′′)2[κ2-O2C{C5H3-3,3′-(SiMe3)2}]}2(µ-κ2:κ2-C2O4)] (3). The concomitant formation of oxalate and carboxylate is unique for CO2 activation, as in previous examples either reduction or insertion is favored to yield a single product. Therefore, thorium(III) CO2 activation can differ from better understood uranium(III) chemistry.

Published
2016
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9. Activation of Heteroallenes CO x S 2- x ( x = 0-2): Experimental and Theoretical Evidence of the Synthetic Versatility of a Bulky Guanidinato Sm II Complex

Author

Castro, Ludovic, Mills, David, Jones, Cameron, Maron, Laurent, Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), School of Chemistry [Manchester], University of Manchester [Manchester], Monash University [Melbourne], School of Chemistry, Monash University, 3800 Clayton, Victoria (Australie), Monash University [Clayton], Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), and School of Chemistry, Monash UniVersity, Clayton, VIC. 3800 (Australia)

Subjects
[CHIM]Chemical Sciences
Abstract

International audience; A joint experimental/theoretical (DFT) study of the activation of heteroallenes COxS2–x (x = 0–2) by [Sm(Giso)2] {Giso– = [(ArN)2CNCy2]–, Cy = cyclohexyl, Ar = 2,6‐diisopropylphenyl} is reported. All heteroallenes are reduced in a different manner. Indeed, while activation of CS2 yields a bimetallic CS2 coupled product through C–S bond formation, CO2 forms an oxalate complex through C–C bond formation. This subsequently undergoes CO2 insertion into one of its Sm–N bonds. Finally, COS activation is predicted to yield a dithiocarbonate complex, through the formation of an intermediate sulfido complex [(Giso)2Sm(µ‐S)Sm(Giso)2]. Therefore, [Sm(Giso)2] is a very versatile reagent, since it is a rare example of a complex that allows formation of several activation products involving valence isoelectronic substrates. This is rationalized by DFT calculations, and the latter emphasizes both the lack of kinetic stability of CS vs. CO and the high thermodynamic stability of the oxalate.

Published
2016

10. Formation of a Bridging Phosphinidene Thorium Complex

Author

Behrle, Andrew, Castro, Ludovic, Maron, Laurent, Walensky, Justin, Department of Chemistry, Missouri University of Science and Technology, 142 Schrenk Hall, 400 West 11th Street, Rolla, Missouri 65409, United States, Missouri University of Science and Technology (Missouri S&T), University of Missouri System-University of Missouri System, Laboratoire de physique et chimie des nano-objets (LPCNO), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph]
Abstract

International audience; The synthesis and structural determination of the first thorium phosphinidene complex are reported. The reaction of 2 equiv of (C5Me5)2Th(CH3)2 with H2P(2,4,6-iPr3C6H2) at 95 °C produces [(C5Me5)2Th]2(μ2-P[(2,6-CH2CHCH3)2-4-iPrC6H2] as well as 4 equiv of methane, 2 equiv from deprotonation of the phosphine and 2 equiv from C–H bond activation of one methyl group of each of the isopropyl groups at the 2- and 6-positions. Transition state calculations indicate that the steps in the mechanism are P–H, C–H, C–H, and then P–H bond activation to form the phosphinidene.

Published
2015

11. Fe‐Based Complexes as Styrene Aziridination Catalysts: Ligand Substitution Tunes Catalyst Activity.

Author

Coin, Guillaume, Patra, Ranjan, Clémancey, Martin, Dubourdeaux, Patrick, Pécaut, Jacques, Lebrun, Colette, Castro, Ludovic, Maldivi, Pascale, Chardon‐Noblat, Sylvie, and Latour, Jean‐Marc

Subjects
AZIRIDINATION, ELECTRON affinity, STYRENE, CATALYSTS, REDUCTION potential
Abstract

As part of our effort to improve our understanding of aziridination mechanism, we used tetra substitution of a diphenol ligand to modify the redox properties of corresponding Fe complexes. This allowed us to confirm that aziridination catalysis by Fe‐based complexes is governed by electron affinity of the active species and further show that it correlates with the FeIII/FeII redox potential. [ABSTRACT FROM AUTHOR]

Published
2019
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12. A Combined Experimental and Theoretical Study of the Versatile Reactivity of an Oxocerium(IV) Complex: Concerted Versus Reductive Addition.

Author

Castro, Ludovic, So, Yat‐Ming, Cho, Chang‐woo, Lortz, Rolf, Wong, Kai‐Hong, Wang, Kai, Arnold, Polly L., Au‐Yeung, Ka‐Chun, Sung, Herman H.‐Y., Williams, Ian D., Leung, Wa‐Hung, and Maron, Laurent

Subjects
*MATHEMATICAL complexes, *MAGNETIC susceptibility, *MAGNETIC measurements, *CERIUM, *SMALL molecules, *WATER
Abstract

A combined experimental and theoretical investigation on the cerium(IV) oxo complex [(LOEt)2Ce(=O)(H2O)]⋅MeC(O)NH2 (1; LOEt−=[Co(η5‐C5H5){P(O)(OEt)2}3]−) demonstrates that the intermediate spin‐state nature of the ground state of the cerium complex is responsible for the versatility of its reactivity towards small molecules such as CO, CO2, SO2, and NO. CASSCF calculations together with magnetic susceptibility measurements indicate that the ground state of the cerium complex is of multiconfigurational character and comprised of 74 % of CeIV and 26 % of CeIII. The latter is found to be responsible for its reductive addition behavior towards CO, SO2, and NO. This is the first report to date on the influence of the multiconfigurational ground state on the reactivity of a metal–oxo complex. [ABSTRACT FROM AUTHOR]

Published
2019
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13. Controlling selectivity in the reductive activation of CO 2 by mixed sandwich uranium( iii ) complexes

Author

Tsoureas, Nikolaos, Castro, Ludovic, Kilpatrick, Alexander, Cloke, F. Geoffey N., Maron, Laurent, School of Life Sciences [Brighton, East Sussex, UK], University of Sussex, Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)

Subjects
[PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph]
Abstract

International audience; The synthesis and molecular structures of a range of uranium(III) mixed sandwich complexes of the type [U(η8-C8H6(1,4-SiMe3)2)(η5-CpMe4R)] (R = Me, Et, iPr, tBu) and their reactivity towards CO2 are reported. The nature of the R group on the cyclopentadienyl ring in the former has a significant effect on the outcome of CO2 activation: when R = Me, the products are the bridging oxo complex {U[η8-C8H6(1,4-SiMe3)2](η5-CpMe5)}2(μ-O) and the bridging oxalate complex {U[η8-C8H6(1,4-SiMe3)2](η5-CpMe5)}2(μ-η2:η2-C2O4); for R = Et or iPr, bridging carbonate {U[η8-C8H6(1,4-SiMe3)2](η5-CpMe4R)}2(μ-η1:η2-CO3) and bridging oxalate complexes {U[η8-C8H6(1,4-SiMe3)2](η5-CpMe4R)}2(μ-η2:η2-C2O4) are formed in both cases; and when R = tBu the sole product is the bridging carbonate complex {U[η8-C8H6(1,4-SiMe3)2](η5-CpMe4tBu)}2(μ-η1:η2-CO3). Electrochemical studies on both the uranium(III) complexes and the dimeric uranium(IV) CO2 reduction products have been carried out and all exhibit quasi reversible redox processes; in particular, the similarities in the U(III)/U(IV) redox couples suggest that the selectivity in the outcome of CO2 reductive activation by these complexes is steric in origin rather than electronic. The latter conclusion is supported by a detailed computational DFT study on the potential mechanistic pathways for reduction of CO2 by this system.

Published
2014
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14. A Theoretical Outlook on the Stereoselectivity Origins of Isoselective Zirconocene Propylene Polymerization Catalysts.

Author

Maron, Laurent, Castro, Ludovic, Therukauff, Gabriel, Carpentier, Jean‐François, Kirillov, Evgueni, Vantomme, Aurelien, Welle, Alexandre, Haspeslagh, Luc, and Brusson, Jean‐Michel

Abstract

Abstract: The first three insertion steps of propylene for isoselective metallocenes from the one‐carbon‐bridged cyclopentadienyl–fluorenyl {Cp/Flu} and silicon‐bridged ansa‐bis(indenyl) {SBI} families were computed by using a theoretical method implementing the B3PW91 functional in combination with solvent corrections incorporated with the Solvation Model based on Density (SMD) continuum model. For C1‐symmetric {Cp/Flu}‐type metallocenes, two mechanisms of stereocontrol were validated theoretically: more facile and more stereoselective chain “stationary” insertion (or site epimerization backskip) and less stereoselective alternating mechanisms. For the C2‐symmetric {SBI}‐type system, the computation results were in complete agreement with the sole operating chain migratory insertion mechanism. The thermochemical data obtained through the study were used to predict microstructures of polypropylenes by using three‐parameter and one‐parameter statistical models for the two metallocene systems, respectively. The calculated meso/rac pentad distributions were found to be in good agreement with those determined experimentally for isotactic polypropylene samples obtained at different polymerization temperatures. [ABSTRACT FROM AUTHOR]

Published
2018
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15. Dinitrogen functionalization at a ditantalum center. Balancing N2 displacement and N2 functionalization in the reaction of coordinated N2 with CS2.

Author

Burford, Richard J., Castro, Ludovic, Maron, Laurent, Hein, Jason E., and Fryzuk, Michael D.

Subjects
*NITROGEN, *CARBON disulfide, *TANTALUM compounds
Abstract

The reaction of carbon disulfide (CS2) with the side-on end-on dinitrogen complex ([NPNSi]Ta)2(μ–η1:η2-N2)(μ-H)2 (1) (where [NPNSi] = [PhP(CH2SiMe2NPh)2]) has been studied and shown to generate two products, the ratio of which depends on the concentration of added carbon disulfide. At high concentrations of CS2, N–N bond cleavage and functionalization occur to generate a ditantalum complex with an isothiocyanato ligand N-bound to Ta along with bridging sulfido and nitrido moieties. At lower concentrations of CS2, less dinitrogen functionalization is observed; instead, N2 is displaced and the CS2 molecule is completely disassembled to generate a ditantalum derivative with bridging methylene and two sulfide moieties. Kinetic and DFT studies have been performed and provide clues about the product ratio and mechanistic information and shed light on why N2 functionalization is challenging. [ABSTRACT FROM AUTHOR]

Published
2018
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16. Dinitrogen functionalization at a ditantalum center. Balancing N2 displacement and N2 functionalization in the reaction of coordinated N2 with CS2.

Author

Burford, Richard J., Castro, Ludovic, Maron, Laurent, Hein, Jason E., and Fryzuk, Michael D.

Subjects
NITROGEN, CARBON disulfide, TANTALUM compounds
Abstract

The reaction of carbon disulfide (CS2) with the side-on end-on dinitrogen complex ([NPNSi]Ta)2(μ–η1:η2-N2)(μ-H)2 (1) (where [NPNSi] = [PhP(CH2SiMe2NPh)2]) has been studied and shown to generate two products, the ratio of which depends on the concentration of added carbon disulfide. At high concentrations of CS2, N–N bond cleavage and functionalization occur to generate a ditantalum complex with an isothiocyanato ligand N-bound to Ta along with bridging sulfido and nitrido moieties. At lower concentrations of CS2, less dinitrogen functionalization is observed; instead, N2 is displaced and the CS2 molecule is completely disassembled to generate a ditantalum derivative with bridging methylene and two sulfide moieties. Kinetic and DFT studies have been performed and provide clues about the product ratio and mechanistic information and shed light on why N2 functionalization is challenging. [ABSTRACT FROM AUTHOR]

Published
2018
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17. Selectivity in the C-H Activation Reaction of CH3OSO2CH3 with [1,2,4-(Me3C)3C5H2]2CeH or [1,2,4-(Me3C)3C5H2][1,2-(Me3C)2-4-(Me2CCH2)C5H2]Ce: To Choose or Not To Choose

Author

Werkema, Evan L., Castro, Ludovic, Maron, Laurent, Eisenstein, Odile, Andersen, Richard A., 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), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, [CHIM.CATA]Chemical Sciences/Catalysis
Abstract

International audience; The experimental reaction of [1,2,4-(Me3C)3C5H2]2CeH, Cp′2CeH, and CH3OSO2CH3 begins by α-C-H activation of the SCH3 group, forming Cp′2CeCH2SO2(OCH3), which evolves into Cp′2CeOCH3 with elimination of CH2 (and presumably SO2). Prolonged heating of this mixture (days at 60 °C) forms Cp′2CeOSO2CH3 and CH3OCH3. The metallacycle [1,2,4-(Me3C)3C5H2][1,2-(Me3C)2-4-(Me2CCH2)C5H2]Ce, when presented with the choice of C-H bonds in CH3S and CH3O groups, deprotonates both with comparable rates, ultimately forming Cp′2CeOCH3 and Cp′2CeOSO2CH3 at 20 °C. The experimental studies are illuminated by DFT calculations on the experimental systems, which show that the hydride selects the more acidic CH3S bond, whereas the metallacycle reacts with C-H bonds of both the CH3S and CH3O groups of CH3OSO2CH3. In the metallacycle reaction, the initially formed regioisomers, Cp′2CeCH2SO2(OCH3) and Cp′2CeCH2OSO2CH3, rearrange to the observed products, Cp′2CeOCH3 and Cp′2CeOSO2CH3, respectively. Furthermore, C-H activation at the SCH3 group forms two isomers of Cp′2CeCH2SO2(OCH3) in the reaction of CH3OSO2CH3 with the metallacycle and only one in the reaction with the hydride. The lack of selectivity in the reactions of the metallacycle relative to the hydride is due to the metallacycle's greater thermodynamic advantage and lower energy barriers, which are linked to the higher bond energy of Ce-H relative to Ce-C in the metallacycle.

Published
2012
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18. Study of nanostructuration of sapphire vicinal surface for application of self organized oxide nanoparticles

Author

Thune, Elsa, Castro, Ludovic, Boulle, Alexandre, Bachelet, R., Guinebretière, René, Segear, Martine, Axe 3 : organisation structurale multiéchelle des matériaux, Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Published
2008

20. Formation of Methane versus Benzene in the Reactions of (C5Me5)2Th(CH3)2 with [CH3PPh3]X (X=Cl, Br, I) Yielding Thorium-Carbene or Thorium-Ylide Complexes.

Author

Rungthanaphatsophon, Pokpong, Bathelier, Adrien, Castro, Ludovic, Behrle, Andrew C., Barnes, Charles L., Maron, Laurent, and Walensky, Justin R.

Subjects
METHANE, BENZENE, CHEMICAL reactions, COMPLEX compounds, CARBENES, PHOSPHONIUM compounds
Abstract

The reaction of (C5Me5)2Th(CH3)2 with the phosphonium salts [CH3PPh3]X (X=Cl, Br, I) was investigated. When X=Br and I, two equivalents of methane are liberated to afford (C5Me5)2Th[CHPPh3]X, rare terminal phosphorano-stabilized carbenes with thorium. These complexes feature the shortest thorium-carbon bonds (≈2.30 Å) reported to date, and electronic structure calculations show some degree of multiple bonding. However, when X=Cl, only one equivalent of methane is lost with concomitant formation of benzene from an unstable phosphorus(V) intermediate, yielding (C5Me5)2Th[κ2-(C,C′)-(CH2)(CH2)PPh2]Cl. Density functional theory (DFT) investigations of the reaction energy profiles for [CH3PPh3]X, X=Cl and I showed that in the case of iodide, thermodynamics prevents the production of benzene and favors formation of the carbene. [ABSTRACT FROM AUTHOR]

Published
2017
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22. International network of provenance trials in cork oak (Quercus suber L.)

Author

Varela, M.C., Almeida, M.H., Chambel, R., Barros, I.R., Bariteau, Michel, Muhs, H., Von Wuehlishl, G., Belarosa, R., Sbay, H., Gil, Gabin, Catalan, G., Iglesias, S., Jiménez, P., Castro, Ludovic, Diaz, P.M., Eriksson, G., Khouja, Mohamed Larbi, Khaldi, Abdelhamid, Estaçao Florestal Nacional, Universidade de Lisboa (ULISBOA), Unité de gestion du département adjoint écologie des forêts prairies et milieux aquatiques (direction), Institut National de la Recherche Agronomique (INRA), Federal Research Centre for Forestry and Forest Products, Tuscia University, Administration des Eaux et Forêts et de la conservation des sols, Partenaires INRAE, Universidad Politécnica de Madrid (UPM), Centro de Investigacion Forestal (INIA-CIFOR), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria = National Institute for Agricultural and Food Research and Technology (INIA), Direccion General de Ambiente, Department of Forest Genetics, Federal Research and Training Centre for Forests Natural Hazards and Landscape, Institut National de Recherche en Génie Rural Eaux et Forêts (INRGREF), and Ecole Nationale du Génie Rural, des Eaux et des Forêts (ENGREF)-Institution de la Recherche et de l'Enseignement Supérieur Agricoles [Tunis] (IRESA)

Subjects
[SDV]Life Sciences [q-bio], ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2002

23. Concomitant Carboxylate and Oxalate Formation From the Activation of CO2 by a Thorium(III) Complex.

Author

Formanuik, Alasdair, Ortu, Fabrizio, Inman, Christopher J., Kerridge, Andrew, Castro, Ludovic, Maron, Laurent, and Mills, David P.

Subjects
CHEMICAL synthesis, CARBOXYLATES, OXALATES, CARBON dioxide reduction, ACTIVATION (Chemistry), THORIUM compounds, GREENHOUSE gases, INSERTION reactions (Chemistry), URANIUM compounds synthesis
Abstract

Improving our comprehension of diverse CO2 activation pathways is of vital importance for the widespread future utilization of this abundant greenhouse gas. CO2 activation by uranium(III) complexes is now relatively well understood, with oxo/carbonate formation predominating as CO2 is readily reduced to CO, but isolated thorium(III) CO2 activation is unprecedented. We show that the thorium(III) complex, [Th(Cp′′)3] ( 1, Cp′′={C5H3(SiMe3)2-1,3}), reacts with CO2 to give the mixed oxalate-carboxylate thorium(IV) complex [{Th(Cp′′)2[κ2-O2C{C5H3-3,3′-(SiMe3)2}]}2(μ-κ2:κ2-C2O4)] ( 3). The concomitant formation of oxalate and carboxylate is unique for CO2 activation, as in previous examples either reduction or insertion is favored to yield a single product. Therefore, thorium(III) CO2 activation can differ from better understood uranium(III) chemistry. [ABSTRACT FROM AUTHOR]

Published
2016
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24. New perspectives in organolanthanide chemistry from redox to bond metathesis: insights from theory.

Author

Kefalidis, Christos E., Castro, Ludovic, Perrin, Lionel, Rosal, Iker Del, and Maron, Laurent

Subjects
*ORGANORARE earth metal compounds, *RARE earth metal compounds, *RARE earth metals, *CHEMICAL structure, *METATHESIS reactions, *CHEMICAL bonds
Abstract

A fifteen year contribution of computational studies carried out in close synergy with experiments is summarized. This interplay has allowed some important breakthroughs in the field of organolanthanide chemistry. The variety of different reaction mechanisms in lanthanide chemistry appear to be broader than the simple bond metathesis. [ABSTRACT FROM AUTHOR]

Published
2016
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26. Activation of Heteroallenes CO xS2- x ( x = 0-2): Experimental and Theoretical Evidence of the Synthetic Versatility of a Bulky Guanidinato SmII Complex.

Author

Castro, Ludovic, Mills, David P., Jones, Cameron, and Maron, Laurent

Subjects
*SAMARIUM compounds, *METAL complexes, *CARBON monoxide, *ALLENE, *COVALENT bonds, *THERMAL stability
Abstract

A joint experimental/theoretical (DFT) study of the activation of heteroallenes CO xS2- x ( x = 0-2) by [Sm(Giso)2] {Giso- = [(ArN)2CNCy2]-, Cy = cyclohexyl, Ar = 2,6-diisopropylphenyl} is reported. All heteroallenes are reduced in a different manner. Indeed, while activation of CS2 yields a bimetallic CS2 coupled product through C-S bond formation, CO2 forms an oxalate complex through C-C bond formation. This subsequently undergoes CO2 insertion into one of its Sm-N bonds. Finally, COS activation is predicted to yield a dithiocarbonate complex, through the formation of an intermediate sulfido complex [(Giso)2Sm(µ-S)Sm(Giso)2]. Therefore, [Sm(Giso)2] is a very versatile reagent, since it is a rare example of a complex that allows formation of several activation products involving valence isoelectronic substrates. This is rationalized by DFT calculations, and the latter emphasizes both the lack of kinetic stability of CS vs. CO and the high thermodynamic stability of the oxalate. [ABSTRACT FROM AUTHOR]

Published
2016
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28. Theoretical treatment of one electron redox transformation of a small molecule using f-element complexes.

Author

Castro, Ludovic, Kefalidis, Christos E., McKay, David, Essafi, Stéphanie, Perrin, Lionel, and Maron, Laurent

Subjects
*SINGLE electron transfer mechanisms, *DENSITY functional theory, *BIMETALLIC catalysts, *REACTIVITY (Chemistry), *ENTHALPY, *GIBBS' energy diagram, *CARBON dioxide reduction
Abstract

The theoretical treatment of single electron transfer (SET) of the redox chemistry mediated by f-element complexes is reviewed and summarized. The different computational strategies to account for the SET energy are presented and commented on the basis of the subsequent mechanistic investigation. Moreover, the mechanistic investigation of the subsequent reactivity, mainly in the field of heteroallene activation, using DFT-based approaches is also summarized. All reported reactivities are found to involve formation of bimetallic species and share in common the formation of the same key intermediate in which the substrate is doubly reduced and stabilized by two oxidized metal centers. Modern computational methods are found to efficiently account for such reactivity. [ABSTRACT FROM AUTHOR]

Published
2014
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29. Computational Insight into 103Rh ChemicalShift–Structure Correlations in Rhodium Bis(phosphine) Complexes.

Author

Ortuño, Manuel A., Castro, Ludovic, and Bühl, Michael

Subjects
*COMPUTATIONAL chemistry, *CHEMICAL shift (Nuclear magnetic resonance), *RHODIUM, *METAL complexes, *PHOSPHINE, *MOLECULAR structure, *LIGAND exchange reactions
Abstract

103Rh NMR chemical shiftshave been computed at theGIAO-B3LYP level of density functional theory (DFT) for a number of[Rh(COD)(P∩P)]+complexes [COD = 1,5-cyclooctadiene,P∩P = chelating bis(phosphine) including bis(dimethylphosphino)ethane(dmpe), bis(diphenylphosphino)ethane (dmpe), MeDUPHOS, DIOP, BINAP,and others]. Structures have been optimized using PBE0 and M06 functionalsin the gas phase, in a continuum modeling the solvent, and with [PF6]−counteranion included explicitly. Observedtrends in δ(103Rh) are well reproduced for pristinePBE0-optimized cations in the gas phase or for ion pairs optimizedin a continuum with M06. While there is no overall trend between computedδ(103Rh) values and complex stabilities (evaluatedthrough isodesmic ligand exchange reactions), there is a linear relationshipbetween the 103Rh chemical shifts and the mean Rh–Pbond distances. This relationship appears to be remarkably general,encompassing various chelating ring sizes and substituents at P, includingremote electron-donating and -withdrawing substituents that are characterizedthrough their Hammett constants. The combination of 103Rh NMR and DFT computations emerges as a useful tool for structureelucidation of Rh–phosphine complexes. [ABSTRACT FROM AUTHOR]

Published
2013
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31. Cleaving bonds in CH3OSO2CF3 with [1,2,4-(Me3C)3C5H2]2CeH; an experimental and computational study.

Author

Werkema, Evan L., Castro, Ludovic, Maron, Laurent, Eisenstein, Odile, and Andersen, Richard A.

Subjects
*ORGANIC synthesis, *ORGANOMETALLIC compounds, *METALLOCENES, *HYDRIDES, *GIBBS' energy diagram, *ORGANOMETALLIC chemistry
Abstract

The reaction at 20 °C of the metallocenelanthanide hydride, [1,2,4-(Me3C)3C5H2]2CeH, UGRAPHIC DISPLAY="INLINE" ID="UGT1" SRC="UGT1"/, and excess methyltrifluoromethanesulfonate, CH3OSO2CF3, results in formation of UGRAPHIC DISPLAY="INLINE" ID="UGT2" SRC="UGT2"/, UGRAPHIC DISPLAY="INLINE" ID="UGT3" SRC="UGT3"/, UGRAPHIC DISPLAY="INLINE" ID="UGT4" SRC="UGT4"/ and the bimetallic complex UGRAPHIC DISPLAY="INLINE" ID="UGT5" SRC="UGT5"/. The metallocenes UGRAPHIC DISPLAY="INLINE" ID="UGT6" SRC="UGT6"/, UGRAPHIC DISPLAY="INLINE" ID="UGT7" SRC="UGT7"/, and UGRAPHIC DISPLAY="INLINE" ID="UGT8" SRC="UGT8"/ react with excess CH3OSO2CF3 to form UGRAPHIC DISPLAY="INLINE" ID="UGT9" SRC="UGT9"/, CH3OCH3, CH3F, and (CH3O)2SO, respectively, at 20 °C. Thus, the net reaction is UGRAPHIC DISPLAY="INLINE" ID="UGT10" SRC="UGT10"/ but the pathway is not a direct methyl transfer. Comparison of the reactivity of CH3OSO2CF3 and CH3OSO2CH3 (Werkema et al., Organometallics, 2012, 31, 870) is revealing since both form a similar set of products but the rates of reaction of CH3OSO2CF3 are faster. The bimetallic complex, in which the SO32− anion bridges two UGRAPHIC DISPLAY="INLINE" ID="UGT11" SRC="UGT11"/ fragments, is unique in organometallic chemistry. The 1H NMR spectrum is fluxional at 20 °C and the low temperature spectrum is consistent with the geometry observed in the solid state. Density Functional Theory (DFT) calculations of the Gibbs energy profiles for the reaction of CH3OSO2CF3 with UGRAPHIC DISPLAY="INLINE" ID="UGT12" SRC="UGT12"/ show that the CH-bond activation and direct CH3 group transfer have similar activation energy barriers. This contrasts with what is observed in the reaction of UGRAPHIC DISPLAY="INLINE" ID="UGT13" SRC="UGT13"/ with CH3OSO2CH3, where CH-bond activation at the SCH3 group is preferred. Remarkably, the activation energy barriers for C–O-bond cleavage are similar in CH3OSO2CH3 and CH3OSO2CF3, which is traced to the calculated small exoergicity of −1.7 kcal mol−1 for the reaction of UGRAPHIC DISPLAY="INLINE" ID="UGT14" SRC="UGT14"/. This contrasts, perhaps, with conventional wisdom that overemphasizes the effect of the electron-withdrawing ability of the CF3 group on the chemical and physical properties of sulfonate esters. [ABSTRACT FROM AUTHOR]

Published
2013
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34. Insights into the Mechanism of Reaction of [(C5Me5)2SmII(thf)2] with CO2 and COS by DFT Studies.

Author

Castro, Ludovic, Labouille, Stéphanie, Kindra, Doug R., Ziller, Joseph W., Nief, Francois, Evans, William J., and Maron, Laurent

Abstract

Reaction mechanisms for the oxidative reactions of CO2 and COS with [(C5Me5)2Sm] have been investigated by means of DFT methods. The experimental formation of oxalate and dithiocarbonate complexes is explained. Their formation involve the samarium(III) bimetallic complexes [(C5Me5)2Sm-CO2-Sm(C5Me5)2] and [(C5Me5)2Sm-COS-Sm(C5Me5)2] as intermediates, respectively, ruling out radical coupling for the formation of the oxalate complex. [ABSTRACT FROM AUTHOR]

Published
2012
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36. Selectivity in the C–HActivation Reactionof CH3OSO2CH3with [1,2,4-(Me3C)3C5H2]2CeH or[1,2,4-(Me3C)3C5H2][1,2-(Me3C)2-4-(Me2CCH2)C5H2]Ce: To Choose or Not To Choose.

Author

Werkema, Evan L., Castro, Ludovic, Maron, Laurent, Eisenstein, Odile, and Andersen, Richard A.

Subjects
*CHEMICAL reactions, *ELIMINATION reactions, *HEATING, *METALLACYCLES, *DENSITY functionals, *BOND energy (Chemistry)
Abstract

The experimental reaction of [1,2,4-(Me3C)3C5H2]2CeH, Cp′2CeH, and CH3OSO2CH3beginsby α-C–Hactivation of the SCH3group, forming Cp′2CeCH2SO2(OCH3), which evolves intoCp′2CeOCH3with elimination of CH2(and presumably SO2). Prolonged heating of thismixture (days at 60 °C) forms Cp′2CeOSO2CH3and CH3OCH3. The metallacycle[1,2,4-(Me3C)3C5H2][1,2-(Me3C)2-4-(Me2CCH2)C5H2]Ce, when presented with the choice of C–H bondsin CH3S and CH3O groups, deprotonates both withcomparable rates, ultimately forming Cp′2CeOCH3and Cp′2CeOSO2CH3at 20 °C. The experimental studies are illuminated by DFT calculationson the experimental systems, which show that the hydride selects themore acidic CH3S bond, whereas the metallacycle reactswith C–H bonds of both the CH3S and CH3O groups of CH3OSO2CH3. In the metallacyclereaction, the initially formed regioisomers, Cp′2CeCH2SO2(OCH3) and Cp′2CeCH2OSO2CH3, rearrange tothe observed products, Cp′2CeOCH3andCp′2CeOSO2CH3, respectively.Furthermore, C–H activation at the SCH3group formstwo isomers of Cp′2CeCH2SO2(OCH3) in the reaction of CH3OSO2CH3with the metallacycle and only one in the reactionwith the hydride. The lack of selectivity in the reactions of themetallacycle relative to the hydride is due to the metallacycle’sgreater thermodynamic advantage and lower energy barriers, which arelinked to the higher bond energy of Ce–H relative to Ce–Cin the metallacycle. [ABSTRACT FROM AUTHOR]

Published
2012
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37. Theoretical study of the solvation of HgCl2, HgClOH, Hg(OH)2and HgCl3−: a density functional theory cluster approachElectronic supplementary information (ESI) available. See DOI: 10.1039/c1cp22154j.

Author

Castro, Ludovic, Dommergue, Aurélien, Renard, Alexandre, Ferrari, Christophe, Ramirez-Solis, Alejandro, and Maron, Laurent

Abstract

The determination of the solvation shell of Hg(ii)-containing molecules and especially the interaction between Hg(ii) and water molecules is the first requirement to understand the transmembrane passage of Hg into the cell. We report a systematic DFT study by stepwise solvation of HgCl2including up to 24 water molecules. In order to include pH and salinity effects, the solvation patterns of HgClOH, Hg(OH)2and HgCl3−were also studied using 24 water molecules. In all cases the hydrogen bond network is crucial to allow orbital-driven interactions between Hg(ii) and the water molecules. DFT Born–Oppenheimer molecular dynamics simulations starting from the stable HgCl2–(H2O)24structure revealed that an HgCl2–(H2O)3trigonal bipyramid effective solute appears and then the remaining 21 water molecules build a complete first solvation shell, in the form of a water-clathrate. In the HgCl2, HgClOH, Hg(OH)2–(H2O)24optimized structures Hg also directly interacts with 3 water molecules from an orbital point of view (three Hg–O donor–acceptor type bonds). All the other interactions are through hydrogen bonding. The cluster-derived solvation energies of HgCl2, HgClOH and Hg(OH)2are estimated to be −34.4, −40.1 and −47.2 kcal mol−1, respectively. [ABSTRACT FROM AUTHOR]

Published
2011
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38. A DFT study of the reactivity of actinidocenes (U, Np and Pu) with pyridine and pyridine N-oxide derivativesElectronic supplementary information (ESI) available: Additional data. See DOI: 10.1039/c002576c.

Author

Castro, Ludovic, Yahia, Ahmed, and Maron, Laurent

Subjects
*DENSITY functionals, *REACTIVITY (Chemistry), *PYRIDINE derivatives, *METAL complexes, *CHEMICAL bonds, *URANIUM compounds, *NEPTUNIUM, *PLUTONIUM
Abstract

The orthoC–H bond activation of several pyridine and pyridine N-oxide derivatives mediated by Cp2An(iv)(CH3)2and Cp2An(iii)(CH3) (Cp = C5H5and An = U, Np, Pu) have been investigated at the DFT level. For uranium(iv) complex, an excellent agreement with experimental observations is found, and particularly in the case of 2-picoline where only orthosp2C–H activation is observed without any sp3C–H activation. These differences of reactivity can be explained by the charges distribution at the metathesis transition state level. A predictive study of the reactivity of neptunium and plutonium complexes with pyridine and pyridine N-oxide is reported. This study shows that neptunium and plutonium have almost the same reactivity. The C–H activation mediated by actinide (iii) complexes have found to be more kinetically and thermodynamically favorable than for actinide (iv) complexes. The influence of 5f electrons on organoactinide reactivity is found to be small by comparing implicit and explicit treatment of 5f electrons. [ABSTRACT FROM AUTHOR]

Published
2010
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39. A DFT study of the reactivity of Cp2AnMe2 with pyridine N-oxide: Towards a predicted different reactivity of U/Pu and Np

Author

Castro, Ludovic, Yahia, Ahmed, and Maron, Laurent

Subjects
*DENSITY functionals, *PYRIDINE, *REACTIVITY (Chemistry), *TRANSURANIUM elements, *ACTINIDE elements, *TRANSPLUTONIUM elements, *REACTION mechanisms (Chemistry), *MOLECULAR models
Abstract

Abstract: A predictive reactivity of Cp2An(IV)Me2 (with An=uranium [U], neptunium [Np] and plutonium [Pu]) with pyridine N-oxide has been studied at the theoretical level. The predictive reaction, which consists in the formation of a formaldehyde complex, begins after the initial formation of a cyclometalated complex produced by a C-H activation of the pyridine N-oxide. A difference of reactivity between U/Pu and Np has been observed and has been attributed to the presence of a more covalent bond between Np and the carbene group in the transition state of formation of a transient carbene intermediate. [ABSTRACT FROM AUTHOR]

Published
2010
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42. A DFT study of the reactions of O3 with Hg° or Br−

Author

Castro, Ludovic, Dommergue, Aurélien, Ferrari, Christophe, and Maron, Laurent

Subjects
*DENSITY functionals, *OZONE layer depletion, *BROMIDES, *MERCURY & the environment, *OXIDATION, *CHEMICAL reactions, ENVIRONMENTAL aspects
Abstract

Abstract: In the mid 1980s the study of ozone reactivity gained a significant interest with the discoveries of the stratospheric ozone hole () and of the ozone depletion events in the polar boundary layer (). In the stratosphere, the mechanism involves heterogeneous reactions on polar stratospheric clouds that lead to chlorine activation (). In contrast, tropospheric ozone depletion occurring during polar springtime rather involves reactive bromine species. They are released during a series of photochemical and heterogeneous reactions often called the bromine explosion (see the review of ). In this reaction sequence, an essential step is the generation of photolyzable Br2, the precursor of two Br atoms, via the multiphasic reaction (1): The production of reactive HOBr could occur with the oxidation of BrO by HO2. [Copyright &y& Elsevier]

Published
2009
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44. Formation of a Uranium Trithiocarbonate Complex via the Nucleophilic Addition of a Sulfide-Bridged Uranium Complex to CS2.

Author

Lam, Oanh P., Castro, Ludovic, Kosog, Boris, Heinemann, Frank W., Maron, Laurent, and Meyer, Karsten

Subjects
*URANIUM, *SULFIDES, *COMPLEX compounds, *NUCLEOPHILIC addition (Chemistry), *SCISSION (Chemistry), *REDUCTIVE elimination (Chemistry)
Abstract

The uranium(IV)/uranium(IV) μ-sulfide complex [{((AdArO)3N)U}2(μ-S)] reacts with CS2 to form the trithiocarbonate-bridged complex [{((AdArO)3N)U}2(μ-K2:K2-CS3)]. The trithiocarbonate complex can alternatively be formed in low yields from low-valent [((AdArO)3N)U(DME)] through the reductive cleavage of CS2. [ABSTRACT FROM AUTHOR]

Published
2012
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46. ChemInform Abstract: New Perspectives in Organolanthanide Chemistry from Redox to Bond Metathesis: Insights from Theory.

Author

Kefalidis, Christos E., Castro, Ludovic, Perrin, Lionel, Rosal, Iker Del, and Maron, Laurent

Subjects
*COORDINATE covalent bond, *ORGANORARE earth metal compounds, *METATHESIS reactions, *COMPUTATIONAL chemistry, *OXIDATION-reduction reaction, *CHEMICAL bonds
Abstract

Review: [a fifteen year contribution of computation studies in close synergy with experiments; 262 refs. [ABSTRACT FROM AUTHOR]

Published
2016
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48. A Theoretical Outlook on the Stereoselectivity Origins of Isoselective Zirconocene Propylene Polymerization Catalysts.

Author

Castro L, Therukauff G, Vantomme A, Welle A, Haspeslagh L, Brusson JM, Maron L, Carpentier JF, and Kirillov E

Abstract

The first three insertion steps of propylene for isoselective metallocenes from the one-carbon-bridged cyclopentadienyl-fluorenyl {Cp/Flu} and silicon-bridged ansa-bis(indenyl) {SBI} families were computed by using a theoretical method implementing the B3PW91 functional in combination with solvent corrections incorporated with the Solvation Model based on Density (SMD) continuum model. For C 1 -symmetric {Cp/Flu}-type metallocenes, two mechanisms of stereocontrol were validated theoretically: more facile and more stereoselective chain "stationary" insertion (or site epimerization backskip) and less stereoselective alternating mechanisms. For the C 2 -symmetric {SBI}-type system, the computation results were in complete agreement with the sole operating chain migratory insertion mechanism. The thermochemical data obtained through the study were used to predict microstructures of polypropylenes by using three-parameter and one-parameter statistical models for the two metallocene systems, respectively. The calculated meso/rac pentad distributions were found to be in good agreement with those determined experimentally for isotactic polypropylene samples obtained at different polymerization temperatures., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Published
2018
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49. Dinitrogen functionalization at a ditantalum center. Balancing N 2 displacement and N 2 functionalization in the reaction of coordinated N 2 with CS 2 .

Author

Burford RJ, Castro L, Maron L, Hein JE, and Fryzuk MD

Abstract

The reaction of carbon disulfide (CS2) with the side-on end-on dinitrogen complex ([NPNSi]Ta)2(μ-η1:η2-N2)(μ-H)2 (1) (where [NPNSi] = [PhP(CH2SiMe2NPh)2]) has been studied and shown to generate two products, the ratio of which depends on the concentration of added carbon disulfide. At high concentrations of CS2, N-N bond cleavage and functionalization occur to generate a ditantalum complex with an isothiocyanato ligand N-bound to Ta along with bridging sulfido and nitrido moieties. At lower concentrations of CS2, less dinitrogen functionalization is observed; instead, N2 is displaced and the CS2 molecule is completely disassembled to generate a ditantalum derivative with bridging methylene and two sulfide moieties. Kinetic and DFT studies have been performed and provide clues about the product ratio and mechanistic information and shed light on why N2 functionalization is challenging.

Published
2018
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50. Formation of Methane versus Benzene in the Reactions of (C 5 Me 5 ) 2 Th(CH 3 ) 2 with [CH 3 PPh 3 ]X (X=Cl, Br, I) Yielding Thorium-Carbene or Thorium-Ylide Complexes.

Author

Rungthanaphatsophon P, Bathelier A, Castro L, Behrle AC, Barnes CL, Maron L, and Walensky JR

Abstract

The reaction of (C 5 Me 5 ) 2 Th(CH 3 ) 2 with the phosphonium salts [CH 3 PPh 3 ]X (X=Cl, Br, I) was investigated. When X=Br and I, two equivalents of methane are liberated to afford (C 5 Me 5 ) 2 Th[CHPPh 3 ]X, rare terminal phosphorano-stabilized carbenes with thorium. These complexes feature the shortest thorium-carbon bonds (≈2.30 Å) reported to date, and electronic structure calculations show some degree of multiple bonding. However, when X=Cl, only one equivalent of methane is lost with concomitant formation of benzene from an unstable phosphorus(V) intermediate, yielding (C 5 Me 5 ) 2 Th[κ 2 -(C,C')-(CH 2 )(CH 2 )PPh 2 ]Cl. Density functional theory (DFT) investigations of the reaction energy profiles for [CH 3 PPh 3 ]X, X=Cl and I showed that in the case of iodide, thermodynamics prevents the production of benzene and favors formation of the carbene., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Published
2017
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