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1. Crystal structure of potassium triethylhydridoborate (`superhydride')

Author

Ann Christin Fecker, Matthias Freytag, Marc D. Walter, and Peter G. Jones

Subjects
crystal structure, potassium, hydridoborate, superhydride, Crystallography, QD901-999
Abstract

In the title compound, formally K+·C6H16B−, the contact sphere of potassium consists of eleven hydrogen atoms from three different anions, assuming an arbitrary cut-off of 3 Å. The shortest interaction, 2.53 (2) Å, involves the hydridic hydrogen H01, which fulfils a bridging function in the formation of chains of KHBEt3 units parallel to the a axis [K1—H01i 2.71 (2) Å, K1—H01—K1ii 126.7 (9)°, operators x∓1/2, −y + {3\over 2}, −z + 1].

Published
2021
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2. NH3 formation from N2 and H2 mediated by molecular tri-iron complexes

Author

Matthias Freytag, Sébastien Bontemps, Marc-Kevin Zaretzke, Dirk Baabe, Iker del Rosal, Katharina Münster, Laurent Maron, Marc D. Walter, Yannick Coppel, Peter G. Jones, Matthias Reiners, Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Laboratoire de chimie de coordination (LCC), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), 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), 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), Deutsche Forschungsgemeinschaft (DFG) - Emmy Noether (WA 2513/2) and Heisenberg (WA 2513/6-8) programs, Humboldt Foundation, Chinese Academy of Science, CNRS, 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)-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), 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
010405 organic chemistry, Chemistry, General Chemical Engineering, Solid-state, Nitrogenase, Protonation, General Chemistry, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, Catalysis, Electron transfer, Ammonia, chemistry.chemical_compound, Polymer chemistry, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Bar (unit)
Abstract

International audience; Living systems carry out the reduction of N2 to ammonia (NH3) through a series of protonation and electron transfer steps under ambient conditions using the enzyme nitrogenase. In the chemical industry, the Haber-Bosch process hydrogenates N2 but requires high temperatures and pressures. Both processes rely on iron-based catalysts, but molecular iron complexes that promote the formation of NH3 on addition of H2 to N2 have remained difficult to devise. Here, we isolate the tri(iron)bis(nitrido) complex [(Cp'Fe)3(μ3-N)2] (in which Cp' = η5-1,2,4-(Me3C)3C5H2), which is prepared by reduction of [Cp'Fe(μ-I)]2 under an N2 atmosphere and comprises three iron centres bridged by two μ3-nitrido ligands. In solution, this complex reacts with H2 at ambient temperature (22 °C) and low pressure (1 or 4 bar) to form NH3. In the solid state, it is converted into the tri(iron)bis(imido) species, [(Cp'Fe)3(μ3-NH)2], by addition of H2 (10 bar) through an unusual solid-gas, single-crystal-to-single-crystal transformation. In solution, [(Cp'Fe)3(μ3-NH)2] further reacts with H2 or H+ to form NH3.

Published
2020
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3. Studies on Molybdena- and Tungstenacyclobutadiene Complexes Supported by Fluoroalkoxy Ligands as Intermediates of Alkyne Metathesis

Author

Laurent Maron, Matthias Freytag, Matthias Tamm, Thomas Bannenberg, Christos E. Kefalidis, Dirk Bockfeld, Henrike Ehrhorn, Tech Univ Carolo Wilhelmina Braunschweig, Inst Math Phys, D-38106 Braunschweig, Germany, INSA Institut National des Sciences Appliquées Hauts-de-France (INSA Hauts-De-France), Institut National des Sciences Appliquées (INSA), 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), Fonds der Chemischen Industrie (FCI), and Deutsche Forschungsgemeinschaft (DFG) [TA 189/12-1]

Subjects
010405 organic chemistry, Chemistry, Organic Chemistry, chemistry.chemical_element, Nuclear magnetic resonance spectroscopy, Tungsten, 010402 general chemistry, 01 natural sciences, Medicinal chemistry, 0104 chemical sciences, Catalysis, Inorganic Chemistry, Molybdenum, Electrophile, Alkyne metathesis, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Physical and Theoretical Chemistry, Chemical equilibrium
Abstract

International audience; The molybdenum and tungsten 2,4,6-trimethylbenzylidynes [MesC M{OC(CF3)(2)Ph}(3)] (12a, M = Mo; 12b, M = W) were prepared and structurally characterized as related complexes to already known [MesC M{OC(CF3)(2)Me}(3)] (MoF6, M = Mo; WF6, M = W). While treatment of 12a with 3-hexyne yielded the propylidyne complex [EtC Mo{OC(CF3)(2)Ph}(3)] (13), the tungsten congener 12b formed isolable metallacyclobutadiene (MCBD) species 14-16 by reaction with 3-hexyne, 1-phenyl-1-propyne, and 2,4-hexadiyne, which can be correlated with the higher electrophilicity of the tungsten complex. Furthermore, the labile MCBD [(C3Et3 )Mo{OC(CF3)(2)Me}(3)] (17) was isolated at low temperature from the reaction of the highly active MoF6 catalyst with 3-hexyne and could be characterized by X-ray diffraction analysis. At room temperature, the same reaction afforded [EtC Mo{OC(CF3)(2)Me}(3)] (18), and the equilibrium reaction with 3-hexyne to form 17 was additionally studied by variable temperature NMR spectroscopy, which allowed determining Delta H degrees and Delta S degrees for the formation of MCBD 17. The experimental thermodynamic data were used to set the benchmark for DFT calculations. Moreover, the deprotiometallacyclobutadiene complex (DPMCBD) [C-3(Mes)(Ph)}Mo{OC(CF3)(3)}(2)] (19), prepared from [MesC Mo{OC(CF3)(3)}(3)] (MoF9) and phenylacetylene, was isolated and structurally characterized as a decomposition product of terminal alkyne metathesis and employed in the polymerization of phenylacetylenes.

Published
2019
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4. Reactivity studies on [Cp ' Fe(mu-I)](2): nitrido-, sulfido- and diselenide iron complexes derived from pseudohalide activation

Author

Peter S. White, Matthias Freytag, Marc D. Walter, Peter G. Jones, Miyuki Maekawa, Matthias Reiners, Constantin G. Daniliuc, Johannes Hohenberger, Jörg Sutter, Laurent Maron, Karsten Meyer, Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], University of North Carolina [Chapel Hill] (UNC), University of North Carolina System (UNC), Inorganic Chemistry, Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM) (ICMM), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], 010405 organic chemistry, Chemistry, Dimer, Inorganic chemistry, General Chemistry, 010402 general chemistry, 01 natural sciences, Magnetic susceptibility, 0104 chemical sciences, Paramagnetism, chemistry.chemical_compound, Crystallography, Oxidation state, Excited state, Mössbauer spectroscopy, [CHIM]Chemical Sciences, Reactivity (chemistry), Density functional theory
Abstract

bibtex: ISI:000400553000098 bibtex\location:'THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND',publisher:'ROYAL SOC CHEMISTRY',type:'Article',affiliation:'Walter, MD (Reprint Author), Tech Univ Carolo Wilhelmina Braunschweig, Inst Anorgan & Analyt Chem, Hagenring 30, D-38106 Braunschweig, Germany. Maron, L (Reprint Author), Univ Toulouse, INSA UPS LPCNO, CNRS LPCNO, 135 Ave Rangueil, F-31077 Toulouse, France. Reiners, Matthias; Maekawa, Miyuki; Daniliuc, Constantin G.; Freytag, Matthias; Jones, Peter G.; Walter, Marc D., Tech Univ Carolo Wilhelmina Braunschweig, Inst Anorgan & Analyt Chem, Hagenring 30, D-38106 Braunschweig, Germany. White, Peter S., Univ N Carolina, Dept Chem, CB 3290, Chapel Hill, NC 27599 USA. Hohenberger, Johannes; Sutter, Joerg; Meyer, Karsten, Univ Erlangen Nurnberg, Dept Chem & Pharm, Inorgan Chem, Egerlandstr 1, D-91058 Erlangen, Germany. Maron, Laurent, Univ Toulouse, INSA UPS LPCNO, CNRS LPCNO, 135 Ave Rangueil, F-31077 Toulouse, France.','author-email':'laurent.maron@irsamc.ups-tlse.fr mwalter@tu-bs.de',da:'2018-12-05','doc-delivery-number':'ET8MH',eissn:'2041-6539','funding-acknowledgement':'Alexander von Humboldt Foundation; NSF [CHE-0615704]; Emmy Noether and Heisenberg program [WA 2513/2, WA 2513/6]; Humboldt Foundation','funding-text':'We thank the Alexander von Humboldt Foundation for a Feodor-Lynen Fellowship (M. D. W.) and Prof. Maurice Brookhart for providing financial support (through NSF Grant CHE-0615704) and laboratory facilities (M. D. W.) during the initial phase of this research program. Deutsche Forschungsgemeinschaft (DFG) is acknowledged for generous funding by the Emmy Noether and Heisenberg program (WA 2513/2 and WA 2513/6, respectively). LM is grateful to the Humboldt Foundation for a grant of experienced researcher and the Chinese Academy of Science. CalMip is also gratefully acknowledged for a generous computational grant.','journal-iso':'Chem. Sci.','keywords-plus':'FE2O2 DIAMOND CORE; STRUCTURAL-CHARACTERIZATION; DINITROGEN ACTIVATION; SULFUR CLUSTERS; SOLVENT PURIFICATION; MOLECULAR-STRUCTURES; ELECTRON-TRANSFER; 2FE-2S CLUSTERS; DOUBLE-BOND; FE-IVN','number-of-cited-references':'106',oa:'DOAJ Gold','orcid-numbers':'Meyer, Karsten/0000-0002-7844-2998 Daniliuc, Constantin G./0000-0002-6709-3673','research-areas':'Chemistry','researcherid-numbers':'Meyer, Karsten/G-2570-2012 Walter, Marc/E-4479-2012','times-cited':'4','unique-id':'ISI:000400553000098','usage-count-last-180-days':'4','usage-count-since-2013':'20','web-of-science-categories':'Chemistry, Multidisciplinary'\; International audience; The iron half-sandwich [Cp'Fe(mu-I)](2) (Cp' = 1,2,4-(Me3C)(3)C5H2, 1) reacts with the pseudohalides NCO-, SCN-, SeCN- and N-3(-) to give [Cp'Fe(mu-NCO)](2) (2), [Cp'Fe(mu-S)](2) (3), [Cp'Fe(mu-Se-2)](2) (4) and [Cp'Fe(mu-N)](2) (5), respectively. Various spectroscopic techniques including X-ray diffraction, solid-state magnetic susceptibility studies and Fe-57 Mossbauer spectroscopy were employed in the characterization of these species. Mossbauer spectroscopy shows a decreasing isomer shift with increasing formal oxidation state, ranging from Fe(II) to Fe(IV), in complexes 1 to 5. The sulfido-bridged dimer 3 exhibits strong antiferromagnetic coupling between the Fe(III) centers. This leads to temperature-independent paramagnetism (TIP) at low temperature, from which the energy gap between the ground and the excited state can be estimated to be 2J = ca. 700 cm(-1). The iron(IV) nitrido complex [Cp'Fe(mu-N)](2) (5) shows no reactivity towards H-2 (10 atm), but undergoes clean reactions with CO (5 bar) and XylNC (Xyl = 2,6-Me2C6H3) to form the diamagnetic isocyanate and carbodiimide complexes [Cp'Fe(CO)(2)(NCO)] (7) and [Cp'Fe(CNXyl)(2)(NCNXyl)] (8), respectively. All compounds were fully characterized, and density functional theory (DFT) computations provide useful insights into their formation and the electronic structures of complexes 3 and 5.

Published
2017
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