Trifluoromethylated Compounds with SiNN and SiON Backbone, and the Crystal Structures of Trimethyl- and Trichloro(trifluoromethyl)silane

2009 ◽  
Vol 64 (1) ◽  
pp. 83-92 ◽  
Author(s):  
Markus Woski ◽  
Norbert W. Mitzel
Keyword(s):  
Gas Phase ◽  
Solution Nmr ◽  
X Ray Diffraction ◽  
Experimental Ir ◽  
In Situ Techniques ◽  
Quantum Chemical Methods ◽  
Conformational Preferences ◽  
Donor Acceptor ◽  
Solid State Structures

The reaction of (F3C)Cl2SiCl3 with the lithiated hydrazine LiN(Me)NMe2 gives the compound (F3C)Cl2SiN(Me)NMe2 (1) and in traces Cl3SiN(Me)NMe2 (2). The reactions with LiN(SiMe3)NMe2 and LiONMe2 give (F3C)Cl2SiN(SiMe3)NMe2 (4) and (F3C)Cl2SiONMe2 (5), respectively. The compounds were characterised by multinuclear solution NMR, gas-phase IR spectroscopy and mass spectrometry. Information about conformational preferences of 1 and 4 can be extracted by comparing experimental IR spectra with those calculated by quantum chemical methods (B3LYP/6-311G**). The former show the gas phase of the β -donor-acceptor silanes 1 and 4 to be dominated by the anti conformations, while the calculations show a preference for the gauche conformers. The crystal structure of Cl3SiN(Me)NMe2 (2) has been determined. The solid-state structures of the Ruppert reagent F3C-SiMe3 (1) and its chlorine analogue F3C-SiCl3 (2) have also been determined by X-ray diffraction of single crystals grown by in situ techniques.

scholarly journals Utilizing the Combined Power of Theory and Experiment to Understand Molecular Structure – Solid-State and Gas-Phase Investigation of Morpholine Borane

2020 ◽  
Vol 73 (8) ◽  
pp. 794
Author(s):  
Aliyu M. Ja'o ◽  
Derek A. Wann ◽  
Conor D. Rankine ◽  
Matthew I. J. Polson ◽  
Sarah L. Masters
Keyword(s):  
Molecular Structure ◽  
Solid State ◽  
Gas Phase ◽  
Hydrogen Generation ◽  
Energy Requirement ◽  
Hydrogen Release ◽  
X Ray Diffraction ◽  
Structural Variations ◽  
Dehydrogenation Reaction ◽  
Quantum Chemical Methods

The molecular structure of morpholine borane complex has been studied in the solid state and gas phase using single-crystal X-ray diffraction, gas electron diffraction, and computational methods. Despite both the solid-state and gas-phase structures adopting the same conformation, a definite decrease in the B–N bond length of the solid-state structure was observed. Other structural variations in the different phases are presented and discussed. To explore the hydrogen storage potential of morpholine borane, the potential energy surface for the uncatalyzed and BH3-catalyzed pathways, as well as the thermochemistry for the hydrogen release reaction, were investigated using accurate quantum chemical methods. It was observed that both the catalyzed and uncatalyzed dehydrogenation pathways are favourable, with a barrier lower than the B–N bond dissociation energy, thus indicating a strong propensity for the complex to release a hydrogen molecule rather than dissociate along the B–N bond axis. A minimal energy requirement for the dehydrogenation reaction has been shown. The reaction is close to thermoneutral as demonstrated by the calculated dehydrogenation reaction energies, thus implying that this complex could demonstrate potential for future on-board hydrogen generation.

scholarly journals Anisotropy of Pt nanoparticles on carbon- and oxide-support and their structural response to electrochemical oxidation probed by in situ techniques

2020 ◽  
Vol 22 (39) ◽  
pp. 22260-22270
Author(s):  
Henrike Schmies ◽  
Arno Bergmann ◽  
Elisabeth Hornberger ◽  
Jakub Drnec ◽  
Guanxiong Wang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Electrochemical Oxidation ◽  
Structural Response ◽  
Pt Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
In Situ Techniques ◽  
Oxide Support ◽  
Pt Dissolution

Investigations on the (electronic) structure of carbon- and oxide-supported Pt nanoparticles during electrochemical oxidation via in situ X-ray diffraction, absorption spectroscopy and the Pt dissolution rate by in situ mass spectrometry.

In Situ X-Ray Diffraction and In Situ X-Ray Absorption Spectroscopy for Investigation of Intercalation Batteries: Application to the Alkaline H+/γ-MnO2 system.

1990 ◽  
Vol 210 ◽  
Author(s):  
C. Lévy-Clèment ◽  
C. Mondoloni ◽  
C. Godart ◽  
R. Cortès
Keyword(s):  
Charge Transfer ◽  
Oxidation State ◽  
Absorption Spectroscopy ◽  
Crystallographic Structure ◽  
X Ray Diffraction ◽  
Alkaline Batteries ◽  
X Ray ◽  
In Situ Techniques ◽  
X Ray Absorption

AbstractThis paper presents applications of in situ X-ray diffraction and absorption techniques to the study of H+/MnO2 alkaline batteries. The two complementary in situ techniques are described. Investigation of the electrochemical insertion and deinsertion of H+ has been made through its influence on the evolution of the crystallographic structure of γ-MnO2, while investigation of the transfer of e has been undertaken through the variation of the oxidation state of the manganese during the discharging and charging process of a battery. New insights in the understanding of the mechanisms of proton insertion and charge transfer into γ-MnO2 are discussed.

scholarly journals In-situ X-ray techniques for non-noble electrocatalysts

2020 ◽  
Vol 92 (5) ◽  
pp. 733-749 ◽  
Author(s):  
Sung-Fu Hung
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Mechanism ◽  
Structural Evolution ◽  
Reduction Reaction ◽  
High Price ◽  
X Ray Diffraction ◽  
X Ray ◽  
In Situ Techniques ◽  
State Variation

AbstractElectrocatalysis offers an alternative solution for the energy crisis because it lowers the activation energy of reaction to produce economic fuels more accessible. Non-noble electrocatalysts have shown their capabilities to practical catalytic applications as compared to noble ones, whose scarcity and high price limit the development. However, the puzzling catalytic processes in non-noble electrocatalysts hinder their advancement. In-situ techniques allow us to unveil the mystery of electrocatalysis and boost the catalytic performances. Recently, various in-situ X-ray techniques have been rapidly developed, so that the whole picture of electrocatalysis becomes clear and explicit. In this review, the in-situ X-ray techniques exploring the structural evolution and chemical-state variation during electrocatalysis are summarized for mainly oxygen evolution reaction (OER), hydrogen evolution reaction (HER), oxygen reduction reaction (ORR), and carbon dioxide reduction reaction (CO2RR). These approaches include X-ray Absorption Spectroscopy (XAS), X-ray diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS). The information seized from these in-situ X-ray techniques can effectively decipher the electrocatalysis and thus provide promising strategies for advancing the electrocatalysts. It is expected that this review could be conducive to understanding these in-situ X-ray approaches and, accordingly, the catalytic mechanism to better the electrocatalysis.

Chemical Vapor Functionalization of ZnO Nanocrystals

2010 ◽  
Vol 1260 ◽  
Author(s):  
Moazzam Ali ◽  
Marty D. Donakowski ◽  
Markus Winterer
Keyword(s):  
Gas Phase ◽  
Diffuse Reflectance ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zno Nanocrystals ◽  
In Series ◽  
Lower Temperature ◽  
Diffuse Reflectance Infrared

AbstractChemical Vapor Functionalization (CVF) is a method in which nanocrystals undergo in situ functionalization in the gas phase. In CVF, two reactors are used in series. The first reactor consists of a hot quartz tube (1073 K) where ZnO nanocrystals are synthesized in the gas phase from diethylzinc and oxygen. The second reactor, connected at the exit of the first one and kept at lower temperature (673 K), is used as functionalization chamber. At the connecting point of the two reactors, vapors of organic functionalizing agents are injected which react with the surface of ZnO nanocrystals. ZnO nanocrystals have been functionalized by 1-hexanol, n-hexanoic acid, n-hexanal and 1-hexylamine. Functionalized ZnO nanocrystals have been characterized by Dynamic Light Scattering, X-ray Diffraction and Diffuse Reflectance Infrared Fourier Transform Spectroscopy.

scholarly journals A Practical Review of the Laser-Heated Diamond Anvil Cell for University Laboratories and Synchrotron Applications

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 459 ◽  
Author(s):  
Simone Anzellini ◽  
Silvia Boccato
Keyword(s):  
Diamond Anvil Cell ◽  
Chemical Properties ◽  
X Ray Diffraction ◽  
In Situ Techniques ◽  
Diamond Anvil ◽  
Properties Of Materials ◽  
Laser Heated ◽  
Physical And Chemical ◽  
And Chemical Properties

In the past couple of decades, the laser-heated diamond anvil cell (combined with in situ techniques) has become an extensively used tool for studying pressure-temperature-induced evolution of various physical (and chemical) properties of materials. In this review, the general challenges associated with the use of the laser-heated diamond anvil cells are discussed together with the recent progress in the use of this tool combined with synchrotron X-ray diffraction and absorption spectroscopy.

Synthesis and Structures of Simple (Silylmethyl)(methyl)ethers

2003 ◽  
Vol 58 (8) ◽  
pp. 759-763 ◽  
Author(s):  
Norbert W. Mitzel
Keyword(s):  
Crystal Structures ◽  
Structural Parameters ◽  
Structural Basis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Donor Acceptor

The compound Cl3SiCH2OCH3 was prepared by reacting ClCH2OCH3 with the Cl3SiH/NEt3 reagent. H3SiCH2OCH3 and F3SiCH2OCH3 were synthesized from Cl3SiCH2OCH3 by reduction with LiAlH4 and by fluorination with SbF3, respectively. The crystal structures of the low-melting compounds H3SiCH2OCH3 and F3SiCH2OCH3 were determined by X-ray diffraction of in situ grown crystals. Both compounds do not show any observable β -donor-acceptor interactions, but behave structurally like usual dialkylethers or silanes, as is obvious from the structural parameters in H3SiCH2OCH3 (<SiCO 108.4(3)-109.4(3)°, <COC 111.0(4)-111.6(4)°) and in F3SiCH2OCH3 (<SiCO 107.1(1), <COC 111.2(2)°). Earlier postulates of Si· · ·O interactions in compounds with SiCO units could thus not be confirmed on a structural basis.

A Neutral Donor-Acceptor p-Stack: Solid-State Structures of 1 : 1 Pyromellitic Diimide-Dialkoxynaphthalene Cocrystals

1997 ◽  
Vol 50 (4) ◽  
pp. 271 ◽  
Author(s):  
Rina Carlini ◽  
Cheng-Lin Fang ◽  
Deborah Herrington ◽  
Kerianne Higgs ◽  
Russell Rodrigo ◽  
...  
Keyword(s):  
Solid State ◽  
Diels Alder ◽  
Hypervalent Iodine ◽  
One Pot ◽  
Neutral Donor ◽  
Donor Acceptor ◽  
Solid State Structures

Substituted ortho-benzoquinones, generated in situ by hypervalent iodine oxidation of catechols, are intercepted by unsymmetrical dienes to provide Diels-Alder adducts with complete regiospecificity. Catechols with carboxy substituents in the 3 or 4 positions react similarly and the initial adducts decarboxylate to produce 8-substituted or 5-substituted 1,2-dihydroxydihydronaphthalenes respectively, in a one-pot three-step sequence. The reaction has been further adapted to produce naphtho[1,8-bc]furans in a one-pot process; its application towards the synthesis of the tricyclic system of the sesquiterpene nardonoxide is described

Influence of the N/Al Ratio in the Gas Phase on the Growth of AlN by High Temperature Chemical Vapor Deposition (HTCVD)

2009 ◽  
Vol 615-617 ◽  
pp. 987-990 ◽  
Author(s):  
Arnaud Claudel ◽  
Elisabeth Blanquet ◽  
Didier Chaussende ◽  
D. Pique ◽  
Michel Pons
Keyword(s):  
Growth Rate ◽  
Gas Phase ◽  
Chemical Vapor ◽  
High Growth ◽  
High Growth Rate ◽  
X Ray Diffraction ◽  
High Crystalline Quality ◽  
X Ray ◽  
Bulk Growth

In order to achieve AlN bulk growth, HTCVD chlorinated process is investigated. High growth rate and high crystalline quality are targeted for AlN films grown on (0001) 4H SiC at 1750°C. The precursors used are ammonia NH3 and aluminium chlorides AlClx species formed in situ by action of Cl2 on high purity Al wire. Influences of N/Al ratio in the gas phase on growth rate, crystalline state and microstructure are presented. Growth rates of up to 200 µm/h have been reached for polycrystalline layers. Thermodynamic calculations were carried out and correlated to the experimental results. As-grown AlN layers were characterized by SEM and X-ray Diffraction. Surface morphology is studied by SEM and FEG-SEM and crystallographic orientations were obtained by X-ray diffraction on θ/2θ.

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