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6 results on '"Christopher J. Hoerger"'

1. CO2 Activation with Formation of Uranium Carbonate Complexes in a Closed Synthetic Cycle

Author

Pablo Waldschmidt, Judith Riedhammer, Christopher J. Hoerger, Frank W. Heinemann, Christina Hauser, and Karsten Meyer

Subjects
Tris, Trimethylsilyl, Ligand, Organic Chemistry, chemistry.chemical_element, Halide, Uranium, Medicinal chemistry, Inorganic Chemistry, chemistry.chemical_compound, chemistry, Yield (chemistry), Carbonate, Physical and Theoretical Chemistry
Abstract

A closed synthetic cycle for the transformation of carbon dioxide to carbonate with a mid-valent tris(aryloxide)-ligated uranium(IV) terminal oxo complex is presented herein. Starting from the previously reported uranium(III) complex, [UIII(OArAd,Ad,Me)3], the uranium(V) terminal oxo complex, obtained by oxidation with N2O or NO, can be reduced with KC8 to yield CO2 activating anionic uranium(IV) oxo complexes [(Ad,Ad,MeArO)3UIV(O)]−. The cycle proceeds with the formation of [(Ad,Ad,MeArO)2(κ2-Ad,Ad,MeArOCO2)UIV(μ-κ1:κ2-CO3)]− upon reaction of the oxo anion with excess CO2 that adds to the terminal oxido ligand and inserts into the uranium–aryloxide bond. Treating this complex with trimethylsilyl halide eliminates both carbonates and generates, for instance, [K(2.2.2-crypt)][(Ad,Ad,MeArO)3UIV(I)2], which can ultimately be reduced with KC8 to recover the trivalent starting material, thus closing the cycle. In contrast, reaction of the 18-crown-6 stabilized U(IV) oxo analogue with CO2 yields a rare and isol...

Published
2020
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2. A Room-Temperature Stable Y(II) Aryloxide: Using Steric Saturation to Kinetically Stabilize Y(II) Complexes

Author

Karsten Meyer, Matthias E. Miehlich, William J. Evans, Samuel A. Moehring, Joseph W. Ziller, and Christopher J. Hoerger

Subjects
Steric effects, Isotope, 010405 organic chemistry, Chemistry, Potassium, chemistry.chemical_element, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, Ion, law.invention, Inorganic Chemistry, Crystallography, law, Graphite, Physical and Theoretical Chemistry, Axial pattern, Saturation (chemistry), Electron paramagnetic resonance
Abstract

The utility of the bulky aryloxide ligands 2,6-Ad2-4-Me-C6H2O- (Ad,Ad,MeArO-) and 2,6-Ad2-4-t-Bu-C6H2O- (Ad,Ad,t-BuArO-; Ad = 1-adamantyl) for stabilizing the Y(II) ion is reported and compared with the results with 2,6-t-Bu2-4-Me-C6H2O- (Ar'O-). In contrast to the reduction product obtained from reducing Y(OAr')3 with potassium graphite, which is only stable in solution for 60 s at room temperature, KC8 reduction of Y(OArAd,Ad,t-Bu)3 in THF in the presence of 2.2.2-cryptand (crypt) produces the room-temperature stable, crystallographically characterizable Y(II) aryloxide [K(crypt)][Y(OArAd,Ad,t-Bu)3]. The X-band EPR spectrum at 77 K shows an axial pattern with resonances centered at g⊥ = 1.97 and g∥ = 2.00 and hyperfine coupling constants of A⊥ = 156.5 G and A∥ = 147.8 G and at room temperature shows an isotropic pattern with giso = 1.98 and Aiso = 153.3 G, which is consistent with an S = 1/2 spin system with nuclear spin I = 1/2 for the 89Y isotope (100% natural abundance).

Published
2020

3. Formation of a Uranium-Bound η1-Cyaphide (CP–) Ligand via Activation and C–O Bond Cleavage of Phosphaethynolate (OCP–)

Author

Frank W. Heinemann, Christopher J. Hoerger, Laurent Maron, Elisa Louyriac, Hansjörg Grützmacher, and Karsten Meyer

Subjects
chemistry.chemical_classification, 010405 organic chemistry, Chemistry, Stereochemistry, Ligand, Organic Chemistry, Center (category theory), chemistry.chemical_element, Salt (chemistry), Halide, Uranium, 010402 general chemistry, Metathesis, 01 natural sciences, Medicinal chemistry, 0104 chemical sciences, Ion, Inorganic Chemistry, Physical and Theoretical Chemistry, Bond cleavage
Abstract

Reaction of the trivalent uranium complex [((Ad,MeArO)3N)U(DME)] with [Na(OCP)(dioxane)2.5] and 2.2.2-crypt yields the μ-oxo-bridged, diuranium complex [Na(2.2.2-crypt)][{((Ad,MeArO)3N)U(DME)}(μ-O){((Ad,MeArO)3N)U(CP)}] (1). Complex 1 features an asymmetric, dinuclear UIV–O–UIV core structure with a cyaphide (CP–) anion η1-CP bound to one of the U ions, and a κ2-O DME coordinated to the other. The CP– ligand is unprecedented in uranium chemistry and is formed through reductive C–O bond cleavage of the phosphaethynolate anion (OCP–). An analogous reaction was performed starting from the tetravalent uranium halide complex [((Ad,MeArO)3N)U(DME)(Cl)]. This salt metathesis approach with [Na(OCP)(dioxane)2.5] results in formation of the mononuclear complex [((Ad,MeArO)3N)U(DME)(OCP)] (2) with an OCP– anion bound to the uranium(IV) center via the oxygen atom in an η1-OCP fashion.

Published
2017
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4. Cyaarside (CAs-) and 1,3-Diarsaallendiide (AsCAs2-) Ligands Coordinated to Uranium and Generated via Activation of the Arsaethynolate Ligand (OCAs-)

Author

Matthias Driess, Frank W. Heinemann, Massimo Rigo, Karsten Meyer, Elisa Louyriac, Christopher J. Hoerger, Laurent Maron, Hansjörg Grützmacher, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-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), Technical University of Berlin / Technische Universität Berlin (TU), German Federal Ministry of Education and Research (BMBF) [02NUK012C, 02NUK020C], COST Action [CM1006], and Friedrich-Alexander-Universitat Erlangen-Nurnberg (FAU)

Subjects
010405 organic chemistry, Ligand, Chemistry, Decarbonylation, chemistry.chemical_element, General Medicine, General Chemistry, Uranium, 010402 general chemistry, 01 natural sciences, Medicinal chemistry, Catalysis, 0104 chemical sciences, arsaethynolate, arsenic, carbon-arsenic triple bonds, diarsaallene, uranium, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Bond cleavage
Abstract

International audience; Reaction of the trivalent uranium complex [(((ArO)-Ar-Ad,Me)(3)N)U(DME)] with one molar equiv [Na(OCAs)(dioxane)(3)], in the presence of 2.2.2-crypt, yields [Na(2.2.2-crypt)][{(((ArO)-Ar-Ad,Me)(3)N)U-IV(THF)}(-O){(((ArO)-Ar-Ad,Me)(3)N)U-IV(CAs)}] (1), the first example of a coordinated (1)-cyaarside ligand (CAs-). Formation of the terminal CAs- is promoted by the highly reducing, oxophilic U-III precursor [(((ArO)-Ar-Ad,Me)(3)N)U(DME)] and proceeds through reductive C-O bond cleavage of the bound arsaethynolate anion, OCAs-. If two equiv of OCAs- react with the U-III precursor, the binuclear, -oxo-bridged U-2(IV/IV) complex [Na(2.2.2-crypt)](2)[{(((ArO)-Ar-Ad,Me)(3)N)U-IV}(2)(-O)(-AsCAs)] (2), comprising the hitherto unknown :(1),(1)-coordinated (AsCAs)(2-) ligand, is isolated. The mechanistic pathway to 2 involves the decarbonylation of a dimeric intermediate formed in the reaction of 1 with OCAs-. An alternative pathway to complex 2 is by conversion of 1 via addition of one further equiv of OCAs-.

Published
2019
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5. Cyaarside (CAs

Author

Christopher J, Hoerger, Frank W, Heinemann, Elisa, Louyriac, Massimo, Rigo, Laurent, Maron, Hansjörg, Grützmacher, Matthias, Driess, and Karsten, Meyer

Abstract

Reaction of the trivalent uranium complex [((

Published
2018

6. Reductive disproportionation of nitric oxide mediated by low-valent uranium

Author

Laurent Maron, Andreas Scheurer, Frank W. Heinemann, Christopher J. Hoerger, Karsten Meyer, Henry S. La Pierre, Department of Chemistry and Pharmacy, Emil Fischer Center, University of Erlangen-Nuremberg, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), School of Chemistry and Biochemistry [Atlanta], Georgia Institute of Technology [Atlanta], 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
Solid-state, chemistry.chemical_element, Disproportionation, 010402 general chemistry, Photochemistry, 01 natural sciences, Medicinal chemistry, Catalysis, Nitric oxide, chemistry.chemical_compound, Materials Chemistry, [CHIM]Chemical Sciences, 010405 organic chemistry, Chemistry, Ligand, Metals and Alloys, General Chemistry, Naturwissenschaftliche Fakultät, Uranium, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Yield (chemistry), ddc:540, Ceramics and Composites, Single crystal
Abstract

The reductive disproportionation of nitric oxide (1 atm) is mediated by the bulky U(III) aryloxide [U(III)(OAr(Ad,Ad,Me))3] ((Ad,Ad,Me)ArO = O-C6H2-2,6-Ad-4-Me) (1) to form the U(V) terminal oxo species [((Ad,Ad,Me)ArO)3U(V)(O)] (2) and N2O, as confirmed by single crystal X-ray diffraction and GC-MS measurements. The reaction is quantitative in the solid state. Mechanistic and theoretical studies of the reaction suggest that the N-N bond is formed by the coupling of an η(1)-O bound nitric oxide ligand with gaseous NO to give an η(1)-(N2O2)(1-) intermediate prior to the spontaneous extrusion of N2O to yield the U(V) terminal oxo species 2.

Published
2016
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