A Conformational Analysis of the Spirocyclic Quaternary Ammonium Cation [(CH2)4N(CH2)4]+ in its Bromide and Picrate Salts

2004 ◽  
Vol 59 (3) ◽  
pp. 259-263 ◽  
Author(s):  
Uwe Monkowius ◽  
Stefan Nogai ◽  
Hubert Schmidbaur
Keyword(s):  
Gas Phase ◽  
Quaternary Ammonium ◽  
Point Group ◽  
High Yield ◽  
X Ray Diffraction ◽  
X Ray ◽  
Quaternary Ammonium Cations ◽  
Twist Conformation ◽  
Twist Form ◽  
Group D

High-yield syntheses of the bromide (1a) and picrate salts (1b) of the 5-azonia-spiro[4]nonane cation [(CH2)4N(CH2)4]+ are reported. In the single crystal X-ray diffraction analyses of the two salts the spirocyclic quaternary ammonium cations have their five-membered rings in envelop and twist conformations modified by packing forces. The conformation found experimentally for 1a has C2-symmetry as predicted for the gas phase by quantum-chemical calculations (RI-DFT, RI-MP2), but the five-membered rings are intermediate between the expected envelop and the twist form. For 1b, both of the two independent cations can be described as a combination of rings in an envelop and a twist conformation. According to the NMR spectra, in solution the cations are highly flexible and pseudosymmetrical (point group D2d)

SEM, XRF, XRD, Nitrogen Adsorption, Fosters Swelling and Capacity Adsorption Characterization of Cloisite 30 B

2012 ◽  
Vol 727-728 ◽  
pp. 1591-1595 ◽  
Author(s):  
Aline Cadigena Lima Patrício ◽  
Marcílio Máximo da Silva ◽  
Anna Karoline Freires de Sousa ◽  
Mariaugusta Ferreira Mota ◽  
Meiry Glaúcia Freire Rodrigues
Keyword(s):  
Quaternary Ammonium ◽  
Cation Exchange Capacity ◽  
Nitrogen Adsorption ◽  
Exchange Capacity ◽  
X Ray Diffraction ◽  
Oil And Grease ◽  
X Ray ◽  
Quaternary Ammonium Cations ◽  
Cloisite 30B

Cationic surfactants, such as quaternary ammonium cations, have been used, in order to ameliorate the oil sorption capacity of inorganics materials, such as clays. Clays modified with quaternary ammonium cations (organoclays) have better performance in sorption, remove oil and grease from water at seven times the rate of activated carbon, as well as they can be used like perforation fluids of oil wells to the oil base, lubricants, among others industries. This work aims characterize the Cloisite 30B using various techniques: X-Ray Diffraction (XRD), Specific Surface Area (BET) and Cation Exchange Capacity. Different organic solvents, namely gasoline, diesel and kerosene were used in order to investigate the clays compatibility after orgophilization.

Ten-Vertex Polyhedral Monocarbaborane Chemistry. The Novel High-Yield Formation of the Ten-Vertex closo Compound [6-(PMe2Ph)-closo-1-CB9H9] from the Thermolysis of [8,8-(PMe2Ph)2-nido-8,7-PtCB9H11]

1993 ◽  
Vol 58 (12) ◽  
pp. 2924-2935 ◽  
Author(s):  
Jane H. Jones ◽  
Bohumil Štíbr ◽  
John D. Kennedy ◽  
Mark Thornton-Pett
Keyword(s):  
Nmr Spectroscopy ◽  
Diffraction Analysis ◽  
High Yield ◽  
Monoclinic Space Group ◽  
The Novel ◽  
X Ray Diffraction ◽  
Metal Centre ◽  
X Ray ◽  
Yield Formation ◽  
Boiling Toluene

Thermolysis of [8,8-(PMe2Ph)2-nido-8,7-PtCB9H11] in boiling toluene solution results in an elimination of the platinum centre and cluster closure to give the ten-vertex closo species [6-(PMe2Ph)-closo-1-CB9H9] in 85% yield as a colourles air stable solid. The product is characterized by NMR spectroscopy and single-crystal X-ray diffraction analysis. Crystals (from hexane-dichloromethane) are monoclinic, space group P21/c, with a = 903.20(9), b = 1 481.86(11), c = 2 320.0(2) pm, β = 97.860(7)° and Z = 8, and the structure has been refined to R(Rw) = 0.045(0.051) for 3 281 observed reflections with Fo > 2.0σ(Fo). The clean high-yield elimination of a metal centre from a polyhedral metallaborane or metallaheteroborane species is very rare.

A Simple High-Yield Synthesis of Gallium(I) Tetrachlorogallate(III) and the Reaction of Digallium Tetrachloride Tetrahydrofuran Solvate with 1,2-Diols

2001 ◽  
Vol 56 (4-5) ◽  
pp. 337-341 ◽  
Author(s):  
Eva S. Schmidt ◽  
Annette Schier ◽  
Norbert W. Mitzel ◽  
Hubert Schmidbaur
Keyword(s):  
Crystalline Phase ◽  
Hydrogen Gas ◽  
High Yield ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metal Atoms ◽  
Gallium Hydride ◽  
Hydroxy Groups ◽  
Tetrahydrofuran Solution ◽  
Analogous Product

Abstract Gallium(I) tetrachlorogallate(III) Ga[GaCU] was prepared in quantitative yield by thermal de­composition of dichlorogallane [HGaCl2]2, which is readily available from Et3SiH and [GaCl3]2. The reaction of catechol with solutions of this gallium(I) tetrachlorogallate(III) in tetrahydrofuran leads to the evolution of hydrogen gas and affords a dinuclear gallium(III) complex with penta-coordinate metal atoms chelated and bridged by mono-deprotonated catechol ligands. In the crystalline phase tetrahydrofuran molecules are hydrogen-bonded to the hydroxy groups: [Ga(1,2 -OC6H4OH)Cl2(C4H8O)]2. The reaction with pinacol also gives hydrogen and the analogous product [Ga(OCMe2CMe2OH)Cl2(C4H8O)]2. The structures of the two compounds have been determined by X-ray diffraction. A mechanism of the new reaction has been proposed which involves oxidative addition of the diol to the solvate (THF)Cl2Ga-GaCl2(THF) present in the tetrahydrofuran solution to give a gallium hydride intermediate.

Phase Characterization and Grain Size Effects of Nanophase Y2O3, ZrO2 and Y2O3-ZrO2 Composites Produced by the Gas-Phase Condensation Technique

1992 ◽  
Vol 286 ◽  
Author(s):  
C. M. Foster ◽  
G. R. Bai ◽  
J. C. Parker ◽  
M. N. Ali
Keyword(s):  
Grain Size ◽  
Raman Scattering ◽  
Gas Phase ◽  
Size Effects ◽  
Structural Evolution ◽  
Deposition Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nanophase Materials ◽  
Phase Characterization

ABSTRACTNanophase (n-) ZrO2 was produced in its pure and partially stabilized form by the gas-phase condensation method. The material was examined by x-ray diffraction and Raman scattering to obtain information on the structural evolution of the material during sintering. Two types of Y2O3 doped ZrO2 nanophase materials were made one by co-deposition of n-Y2O3 and n-ZrO2 in a consecutive manner and the second by mechanically mixing n-Y2O3 and n-ZrO2. We have determined that the co-deposition process is the most effect means of doping the n-ZrO2.

scholarly journals Observation and Characterization of Fragile Organometallic Molecules Encapsulated in Single-Wall Carbon Nanotubes

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Daisuke Ogawa ◽  
Ryo Kitaura ◽  
Takeshi Saito ◽  
Shinobu Aoyagi ◽  
Eiji Nishibori ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
High Yield ◽  
Single Wall Carbon Nanotubes ◽  
X Ray Diffraction ◽  
Single Wall Carbon ◽  
X Ray ◽  
Transmission Electron ◽  
Organometallic Molecules ◽  
X Ray Absorption

Thermally fragile tris(η5-cyclopentadienyl)erbium (ErCp3) molecules are encapsulated in single-wall carbon nanotubes (SWCNTs) with high yield. We realized the encapsulation of ErCp3with high filling ratio by using high quality SWCNTs at an optimized temperature under higher vacuum. Structure determination based on high-resolution transmission electron microscope observations together with the image simulations reveals the presence of almost free rotation of each ErCp3molecule in SWCNTs. The encapsulation is also confirmed by X-ray diffraction. Trivalent character of Er ions (i.e., Er3+) is confirmed by X-ray absorption spectrum.

X-Ray Diffraction

2021 ◽  
pp. 408-480
Author(s):  
Kannan M. Krishnan
Keyword(s):  
Point Group ◽  
Polycrystalline Materials ◽  
X Rays ◽  
X Ray Diffraction ◽  
Symmetry Point Group ◽  
X Ray ◽  
Atomic Scattering ◽  
Scattering Factor ◽  
Diffraction Patterns ◽  
Lattice Planes

X-rays diffraction is fundamental to understanding the structure and crystallography of biological, geological, or technological materials. X-rays scatter predominantly by the electrons in solids, and have an elastic (coherent, Thompson) and an inelastic (incoherent, Compton) component. The atomic scattering factor is largest (= Z) for forward scattering, and decreases with increasing scattering angle and decreasing wavelength. The amplitude of the diffracted wave is the structure factor, F hkl, and its square gives the intensity. In practice, intensities are modified by temperature (Debye-Waller), absorption, Lorentz-polarization, and the multiplicity of the lattice planes involved in diffraction. Diffraction patterns reflect the symmetry (point group) of the crystal; however, they are centrosymmetric (Friedel law) even if the crystal is not. Systematic absences of reflections in diffraction result from glide planes and screw axes. In polycrystalline materials, the diffracted beam is affected by the lattice strain or grain size (Scherrer equation). Diffraction conditions (Bragg Law) for a given lattice spacing can be satisfied by varying θ or λ — for study of single crystals θ is fixed and λ is varied (Laue), or λ is fixed and θ varied to study powders (Debye-Scherrer), polycrystalline materials (diffractometry), and thin films (reflectivity). X-ray diffraction is widely applied.

scholarly journals Towards the Application of Supramolecular Self-Associating Amphiphiles as Next-Generation Delivery Vehicles

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4126
Author(s):  
Lisa J. White ◽  
Jessica E. Boles ◽  
Kira L. F. Hilton ◽  
Rebecca J. Ellaby ◽  
Jennifer R. Hiscock
Keyword(s):  
Gas Phase ◽  
High Resolution Mass Spectrometry ◽  
Next Generation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Guest Species ◽  
Solvent Environment ◽  
Delivery Vehicles ◽  
Self Association ◽  
Aqueous Conditions

Herein, we present a series of supramolecular self-associating amphiphilic (SSA) salts and establish the potential for these molecular constructs to act as next-generation solution-state molecular delivery vehicles. We characterise the self-association of these SSAs, both alone and when co-formulated with a variety of drug(like) competitive guest species. Single crystal X-ray diffraction studies enable the observation of hydrogen-bonded self-association events in the solid state, whilst high resolution mass spectrometry confirms the presence of anionic SSA dimers in the gas-phase. These same anionic SSA dimeric species are also identified within a competitive organic solvent environment (DMSO-d6/0.5% H2O). However, extended self-associated aggregates are observed to form under aqueous conditions (H2O/5.0% EtOH) in both the absence and presence of these competitive guest species. Finally, through the completion of these studies, we present a framework to support others in the characterisation of such systems.

Pentamethylcyclopentadienyl-Vanadium Complexes Containing Halogeno- and Oxo-Ligands

1987 ◽  
Vol 42 (12) ◽  
pp. 1520-1526 ◽  
Author(s):  
Max Herberhold ◽  
Walter Kremnitz ◽  
Markus Kuhnlein ◽  
Manfred L. Ziegler ◽  
Karl Brunn
Keyword(s):  
Crystal Structure ◽  
Mass Spectra ◽  
High Yield ◽  
Vanadium Complexes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bond Lengths ◽  
Oxygen Bond ◽  
Single Bonds ◽  
Oxo Ligands

AbstractA simple and high-yield preparation of the pentamethylcyclopentadienyl vanadium(IV) trihalides Cp*VX3 (X = CL, Br, I) from Cp*V(CO)4 as well as their conversion into the oxo-vanadium(V) compounds Cp*VOX2 (X = CL, Br) and [Cp*VOX]2(μ-O) (X = CL, Br, I) are described. The equilibrium between the two fluoride species Cp*VOF2 and [Cp*VOF]2(μ-O) has also been investigated. The complexes are characterized by their NMR (51V, l3C, 1H), IR, and mass spectra. The crystal structure of the binuclear chloro-oxo complex [Cp*VOCl]2(μ-O) has been determined by X-ray diffraction. The molecules contain two [Cp*VOCl] units combined via a bent oxo bridge (V-O-V angle of 142.2(2)°). The vanadium-oxygen bond lengths are 157.6(8) and 179.4(1) pm for the terminal and the bridging oxo ligands, respectively, corresponding to double and single bonds.

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