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Lyndon Emsley - One of the best experts on this subject based on the ideXlab platform.
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Molecular Understanding of the Formation of Surface Zirconium Hydrides upon Thermal Treatment under Hydrogen of [(⋮SiO)Zr(CH 2 t Bu) 3 ] by Using Advanced Solid-State NMR Techniques
Journal of the American Chemical Society, 2004Co-Authors: Franck Rataboul, Anne Baudouin, Chloe Thieuleux, Laurent Veyre, Christophe Coperet, Jeanmarie Basset, A Lesage, Jean Thivolle-cazat, Lyndon EmsleyAbstract:The reaction of [([triple bond]SiO)Zr(CH(2)tBu)(3)] with H(2) at 150 degrees C leads to the hydrogenolysis of the Zirconium-carbon bonds to form a very reactive hydride intermediate(s), which further reacts with the surrounding siloxane ligands present at the surface of this support to form mainly two different Zirconium Hydrides: [([triple bond]SiO)(3)Zr-H] (1a, 70-80%) and [([triple bond]SiO)(2)ZrH(2)] (1b, 20-30%) along with silicon Hydrides, [([triple bond]SiO)(3)SiH] and [([triple bond]SiO)(2)SiH(2)]. Their structural identities were identified by (1)H DQ solid-state NMR spectroscopy as well as reactivity studies. These two species react with CO(2) and N(2)O to give, respectively, the corresponding formate [([triple bond]SiO)(4-x)Zr(O-C(=O)H)(x)] (2) and hydroxide complexes [([triple bond]SiO)(4-x)Zr(OH)(x)] (x = 1 or 2 for 3a and 3b, respectively) as major surface complexes.
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molecular understanding of the formation of surface Zirconium Hydrides upon thermal treatment under hydrogen of sio zr ch 2 tbu 3 by using advanced solid state nmr techniques
Journal of the American Chemical Society, 2004Co-Authors: Franck Rataboul, Anne Baudouin, Chloe Thieuleux, Laurent Veyre, Christophe Coperet, Jean Thivollecazat, Jeanmarie Basset, A Lesage, Lyndon EmsleyAbstract:The reaction of [([triple bond]SiO)Zr(CH(2)tBu)(3)] with H(2) at 150 degrees C leads to the hydrogenolysis of the Zirconium-carbon bonds to form a very reactive hydride intermediate(s), which further reacts with the surrounding siloxane ligands present at the surface of this support to form mainly two different Zirconium Hydrides: [([triple bond]SiO)(3)Zr-H] (1a, 70-80%) and [([triple bond]SiO)(2)ZrH(2)] (1b, 20-30%) along with silicon Hydrides, [([triple bond]SiO)(3)SiH] and [([triple bond]SiO)(2)SiH(2)]. Their structural identities were identified by (1)H DQ solid-state NMR spectroscopy as well as reactivity studies. These two species react with CO(2) and N(2)O to give, respectively, the corresponding formate [([triple bond]SiO)(4-x)Zr(O-C(=O)H)(x)] (2) and hydroxide complexes [([triple bond]SiO)(4-x)Zr(OH)(x)] (x = 1 or 2 for 3a and 3b, respectively) as major surface complexes.
Kurt A. Terrani - One of the best experts on this subject based on the ideXlab platform.
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thermal expansion behavior of δ Zirconium Hydrides comparison of δ hydride powder and platelets
Journal of Nuclear Materials, 2018Co-Authors: Nedim M Cinbiz, Kurt A. TerraniAbstract:Abstract The thermal expansion coefficient of δ Hydrides and the evolution of the d-spacing of δ hydride platelets in Zircaloy-4 during heat treatments were investigated by conducting synchrotron x-ray diffraction experiments. Identical experiments enabled a direct comparison of the d-spacing of δ Zirconium hydride platelets with the d-spacing of the powder δ Hydrides. By analyzing the experimental data of this study and the data available in the literature, the thermal expansion coefficient of pure δ Hydrides was determined as 14.1 10−6 °C−1. A direct comparison of the d-spacings of δ hydride platelets in CWSR Zry-4 sheet and the powder δ hydride samples showed an evolution of temperature-dependent strains within the δ hydride precipitates in which the strain components normal to the platelet edges exceed that normal to the platelet face during cooling/precipitation but not during heating/dissolution above approx. 200 °C.
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Nanoindentation study of bulk Zirconium Hydrides at elevated temperatures
Journal of Alloys and Compounds, 2017Co-Authors: M. Nedim Cinbiz, Mehdi Balooch, Aida Amroussia, Kurt A. TerraniAbstract:Abstract The mechanical properties of Zirconium Hydrides were studied using nano-indentation technique between 25 and 400 °C. Temperature dependency of reduced elastic modulus and hardness of δ- and e-Zirconium Hydrides were obtained by conducting nanoindentation experiments on bulk hydride samples with independently heating capability of indenter and heating stage. The reduced elastic modulus of δ-Zirconium hydride (H/Zr ratio = 1.61) decreased from ∼113 GPa at room temperature to ∼109 GPa at 400 °C, while its hardness decreased significantly from 4.1 GPa to 2.41 GPa in the same temperature range. For e-Zirconium Hydrides (H/Zr ratio = 1.79), the reduced elastic modulus decreased from 61 GPa at room temperature to 54 GPa at 300 °C, while its hardness from 3.06 GPa to 2.19 GPa.
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incoherent quasielastic neutron scattering study of hydrogen diffusion in thorium Zirconium Hydrides
Journal of Nuclear Materials, 2010Co-Authors: Kurt A. Terrani, Mehdi Balooch, Eugene Mamontov, D R OlanderAbstract:Abstract Monophase thorium–Zirconium Hydrides (ThZr2Hx) have been fabricated starting from a metallic alloy and the hydrogen stoichiometry determined by X-ray diffraction. Incoherent Quasielastic Neutron Scattering (IQNS) on the Hydrides was conducted over the temperature range 650–750 K at the Backscattering Silicon Spectrometer (BASIS) at the Spallation Neutron Source (SNS) at ORNL. The isotropic Chudley–Elliott model was utilized to analyze the quasielastic linewidth broadening data as function of momentum transfer. The diffusion coefficient and average jump distance of hydrogen atoms in ThZr2H5.6 and ThZr2H6.2 were extracted from the measurements.
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The kinetics of hydrogen desorption from and adsorption on Zirconium hydride
Journal of Nuclear Materials, 2009Co-Authors: Kurt A. Terrani, Mehdi Balooch, Doonyapong Wongsawaeng, Sarawut Jaiyen, Donald R. OlanderAbstract:Abstract Three sets of independent experiments were conducted to determine the kinetics of hydrogen desorption from and adsorption on δ-Zirconium Hydrides. One method involved measurement of hydrogen gas pressure-buildup as a result of dehydriding in a closed vessel. The other two involved thermogravimetric experiments, measuring the rate of mass loss during dehydriding under vacuum. Zeroth-order desorption and first order (with respect to gas-phase hydrogen) adsorption kinetics was determined. The Arrhenius dependence of rate constants showed excellent agreement among different experimental data. The activation energies for desorption and adsorption processes were determined as 205 ± 8 and 86 ± 15 kJ mol −1 respectively.
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fabrication and characterization of uranium thorium Zirconium Hydrides
Journal of Nuclear Materials, 2009Co-Authors: Kurt A. Terrani, Mehdi Balooch, Charles B. Yeamans, G Chinthaka W Silva, Donald R. OlanderAbstract:Abstract Two uranium–thorium–Zirconium Hydrides, (UTh 4 Zr 10 )H 1.9 and (U 4 Th 2 Zr 9 )H 1.5 , have been fabricated and characterized. Fabrication involved arc melting of the constituent pure metals to form homogenous alloys, followed by hydriding at elevated temperatures in a hydrogen gas environment. The compounds were characterized by X-ray powder diffractometry as well as scanning and transmission electron microscopy. These methods revealed a multi-phase mixture of δ-Zirconium hydride (ZrH 1.6+ x ), thorium–Zirconium hydride (ThZr 2 H 7− x ), and uranium metal. The elastic modulus was mapped across the microstructure using nanoscale dynamic stiffness mapping. The elastic modulus of ThZr 2 H 7− x phase is found to be 172 GPa.
Jeanmarie Basset - One of the best experts on this subject based on the ideXlab platform.
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c h and c c activation of n butane with Zirconium Hydrides supported on sba15 containing n donor ligands sinh six zrh2 sinh six 2zrh and sin six zrh x nh o a dft study
Organometallics, 2014Co-Authors: F A Pasha, Anissa Bendjeriousedjerari, Kuowei Huang, Jeanmarie BassetAbstract:Density functional theory (DFT) was used to elucidate the mechanism of n-butane hydrogenolysis (into propane, ethane, and methane) on well-defined Zirconium Hydrides supported on SBA15 coordinated to the surface via N-donor surface pincer ligands: [(≡SiNH−)(≡SiO−)ZrH2] (A), [(≡SiNH−)2ZrH2] (B), [(≡SiNH−)(≡SiO−)2ZrH] (C), [(≡SiNH−)2(≡SiO−)ZrH] (D), [(≡SiN═)(≡Si–O−)ZrH] (E), and [(≡SiN═)(≡SiNH−)ZrH] (F). The roles of these Hydrides have been investigated in C–H/C–C bond activation and cleavage. The dihydride A linked via a chelating [N,O] surface ligand was found to be more active than B, linked to the chelating [N,N] surface ligand. Moreover, the dihydride Zirconium complexes are also more active than their corresponding monoHydrides C–F. The C–C cleavage step occurs preferentially via β-alkyl transfer, which is the rate-limiting step in the alkane hydrogenolysis. The energetics of the comparative pathways over the potential energy surface diagram (PES) reveals the hydrogenolysis of n-butane into propane a...
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Molecular Understanding of the Formation of Surface Zirconium Hydrides upon Thermal Treatment under Hydrogen of [(⋮SiO)Zr(CH 2 t Bu) 3 ] by Using Advanced Solid-State NMR Techniques
Journal of the American Chemical Society, 2004Co-Authors: Franck Rataboul, Anne Baudouin, Chloe Thieuleux, Laurent Veyre, Christophe Coperet, Jeanmarie Basset, A Lesage, Jean Thivolle-cazat, Lyndon EmsleyAbstract:The reaction of [([triple bond]SiO)Zr(CH(2)tBu)(3)] with H(2) at 150 degrees C leads to the hydrogenolysis of the Zirconium-carbon bonds to form a very reactive hydride intermediate(s), which further reacts with the surrounding siloxane ligands present at the surface of this support to form mainly two different Zirconium Hydrides: [([triple bond]SiO)(3)Zr-H] (1a, 70-80%) and [([triple bond]SiO)(2)ZrH(2)] (1b, 20-30%) along with silicon Hydrides, [([triple bond]SiO)(3)SiH] and [([triple bond]SiO)(2)SiH(2)]. Their structural identities were identified by (1)H DQ solid-state NMR spectroscopy as well as reactivity studies. These two species react with CO(2) and N(2)O to give, respectively, the corresponding formate [([triple bond]SiO)(4-x)Zr(O-C(=O)H)(x)] (2) and hydroxide complexes [([triple bond]SiO)(4-x)Zr(OH)(x)] (x = 1 or 2 for 3a and 3b, respectively) as major surface complexes.
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molecular understanding of the formation of surface Zirconium Hydrides upon thermal treatment under hydrogen of sio zr ch 2 tbu 3 by using advanced solid state nmr techniques
Journal of the American Chemical Society, 2004Co-Authors: Franck Rataboul, Anne Baudouin, Chloe Thieuleux, Laurent Veyre, Christophe Coperet, Jean Thivollecazat, Jeanmarie Basset, A Lesage, Lyndon EmsleyAbstract:The reaction of [([triple bond]SiO)Zr(CH(2)tBu)(3)] with H(2) at 150 degrees C leads to the hydrogenolysis of the Zirconium-carbon bonds to form a very reactive hydride intermediate(s), which further reacts with the surrounding siloxane ligands present at the surface of this support to form mainly two different Zirconium Hydrides: [([triple bond]SiO)(3)Zr-H] (1a, 70-80%) and [([triple bond]SiO)(2)ZrH(2)] (1b, 20-30%) along with silicon Hydrides, [([triple bond]SiO)(3)SiH] and [([triple bond]SiO)(2)SiH(2)]. Their structural identities were identified by (1)H DQ solid-state NMR spectroscopy as well as reactivity studies. These two species react with CO(2) and N(2)O to give, respectively, the corresponding formate [([triple bond]SiO)(4-x)Zr(O-C(=O)H)(x)] (2) and hydroxide complexes [([triple bond]SiO)(4-x)Zr(OH)(x)] (x = 1 or 2 for 3a and 3b, respectively) as major surface complexes.
Jun Okuda - One of the best experts on this subject based on the ideXlab platform.
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neutral and cationic Zirconium Hydrides supported by a dianionic nnnn type macrocycle ligand
Organometallics, 2015Co-Authors: Heiko Kulinna, Thomas P Spaniol, Jun OkudaAbstract:Hydrogenation of bis(trimethylsilylmethyl) Zirconium complex [Zr(Me2TACD)(CH2SiMe3)2] (1), prepared by reacting [Zr(CH2SiMe3)4] with 1,7-dimethyl-1,4,7,10-tetraazacyclododecane (Me2TACD)H2, gave dinuclear alkyl hydride complex [Zr(Me2TACD)(CH2SiMe3)2(μ-H)2Zr(Me2TACD)] (2). According to NMR spectroscopic and single-crystal X-ray diffraction studies, 2 exhibits a Cs-symmetrical structure with two distinct Zirconium centers, one eight- and the other seven-coordinate, bridged by an amido donor and two Hydrides. Abstraction of the trimethylsilylmethyl groups by the weak Bronsted acid [NEt3H][B(3,5-C6H3Cl2)4] gave the monocationic mono(alkyl) dihydride [Zr(Me2TACD)(CH2SiMe3)(μ-H)2Zr(Me2TACD)][B(3,5-C6H3Cl2)4] (3) and the dicationic hydride complex [Zr(Me2TACD)(THF)2(μ-H)2Zr(Me2TACD)][B(3,5-C6H3Cl2)4]2 (4). X-ray crystallography of the cationic complexes 3 and 4 revealed a Cs-symmetrical dinuclear structure derived from that of 2.
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Neutral and Cationic Zirconium Hydrides Supported by a Dianionic (NNNN)-Type Macrocycle Ligand
2015Co-Authors: Heiko Kulinna, Thomas P Spaniol, Jun OkudaAbstract:Hydrogenation of bis(trimethylsilylmethyl) Zirconium complex [Zr(Me2TACD)(CH2SiMe3)2] (1), prepared by reacting [Zr(CH2SiMe3)4] with 1,7-dimethyl-1,4,7,10-tetraazacyclododecane (Me2TACD)H2, gave dinuclear alkyl hydride complex [Zr(Me2TACD)(CH2SiMe3)2(μ-H)2Zr(Me2TACD)] (2). According to NMR spectroscopic and single-crystal X-ray diffraction studies, 2 exhibits a Cs-symmetrical structure with two distinct Zirconium centers, one eight- and the other seven-coordinate, bridged by an amido donor and two Hydrides. Abstraction of the trimethylsilylmethyl groups by the weak Brønsted acid [NEt3H][B(3,5-C6H3Cl2)4] gave the monocationic mono(alkyl) dihydride [Zr(Me2TACD)(CH2SiMe3)(μ-H)2Zr(Me2TACD)][B(3,5-C6H3Cl2)4] (3) and the dicationic hydride complex [Zr(Me2TACD)(THF)2(μ-H)2Zr(Me2TACD)][B(3,5-C6H3Cl2)4]2 (4). X-ray crystallography of the cationic complexes 3 and 4 revealed a Cs-symmetrical dinuclear structure derived from that of 2
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cationic Zirconium Hydrides supported by an nnnn type macrocyclic ligand synthesis structure and reactivity
Inorganic Chemistry, 2012Co-Authors: Heiko Kulinna, Thomas P Spaniol, Laurent Maron, Jun OkudaAbstract:An air- and light-sensitive, but thermally stable tris[(trimethylsilyl)methyl]Zirconium complex containing an NNNN-type macrocyclic ligand [Zr(Me3TACD)(CH2SiMe3)3] (1; Me3TACD = Me3[12]aneN4: 1,4,7...
Christophe Coperet - One of the best experts on this subject based on the ideXlab platform.
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Reactivity of silica supported Zirconium hydride towards N2O and CO2 probe molecules: a computational point of view
New Journal of Chemistry, 2014Co-Authors: Mahboubeh Poor Kalhor, Christophe Coperet, Raphael Wischert, Henry ChermetteAbstract:The reactivity of supported Zirconium Hydrides toward probe molecules like N2O and CO2 has shown that both Hydrides are converted to the corresponding hydroxide and formate species, which were characterized by IR and NMR spectroscopies. Their reactivity towards these probe molecules is analyzed through DFT (density functional theory) calculations. The computed spectroscopic IR and NMR signatures are fully consistent with experimental observations.
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Molecular Understanding of the Formation of Surface Zirconium Hydrides upon Thermal Treatment under Hydrogen of [(⋮SiO)Zr(CH 2 t Bu) 3 ] by Using Advanced Solid-State NMR Techniques
Journal of the American Chemical Society, 2004Co-Authors: Franck Rataboul, Anne Baudouin, Chloe Thieuleux, Laurent Veyre, Christophe Coperet, Jeanmarie Basset, A Lesage, Jean Thivolle-cazat, Lyndon EmsleyAbstract:The reaction of [([triple bond]SiO)Zr(CH(2)tBu)(3)] with H(2) at 150 degrees C leads to the hydrogenolysis of the Zirconium-carbon bonds to form a very reactive hydride intermediate(s), which further reacts with the surrounding siloxane ligands present at the surface of this support to form mainly two different Zirconium Hydrides: [([triple bond]SiO)(3)Zr-H] (1a, 70-80%) and [([triple bond]SiO)(2)ZrH(2)] (1b, 20-30%) along with silicon Hydrides, [([triple bond]SiO)(3)SiH] and [([triple bond]SiO)(2)SiH(2)]. Their structural identities were identified by (1)H DQ solid-state NMR spectroscopy as well as reactivity studies. These two species react with CO(2) and N(2)O to give, respectively, the corresponding formate [([triple bond]SiO)(4-x)Zr(O-C(=O)H)(x)] (2) and hydroxide complexes [([triple bond]SiO)(4-x)Zr(OH)(x)] (x = 1 or 2 for 3a and 3b, respectively) as major surface complexes.
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molecular understanding of the formation of surface Zirconium Hydrides upon thermal treatment under hydrogen of sio zr ch 2 tbu 3 by using advanced solid state nmr techniques
Journal of the American Chemical Society, 2004Co-Authors: Franck Rataboul, Anne Baudouin, Chloe Thieuleux, Laurent Veyre, Christophe Coperet, Jean Thivollecazat, Jeanmarie Basset, A Lesage, Lyndon EmsleyAbstract:The reaction of [([triple bond]SiO)Zr(CH(2)tBu)(3)] with H(2) at 150 degrees C leads to the hydrogenolysis of the Zirconium-carbon bonds to form a very reactive hydride intermediate(s), which further reacts with the surrounding siloxane ligands present at the surface of this support to form mainly two different Zirconium Hydrides: [([triple bond]SiO)(3)Zr-H] (1a, 70-80%) and [([triple bond]SiO)(2)ZrH(2)] (1b, 20-30%) along with silicon Hydrides, [([triple bond]SiO)(3)SiH] and [([triple bond]SiO)(2)SiH(2)]. Their structural identities were identified by (1)H DQ solid-state NMR spectroscopy as well as reactivity studies. These two species react with CO(2) and N(2)O to give, respectively, the corresponding formate [([triple bond]SiO)(4-x)Zr(O-C(=O)H)(x)] (2) and hydroxide complexes [([triple bond]SiO)(4-x)Zr(OH)(x)] (x = 1 or 2 for 3a and 3b, respectively) as major surface complexes.
