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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Kinetic and equilibrium studies of cyclodextrin-azo dye inclusion complexes /

Clarke, Ronald James, January 1985 (has links) (PDF)
Thesis (Ph. D.)--University of Adelaide, Dept. of Physical and Inorganic Chemistry, 1985. / Offprints of two author's journal articles inserted at end of the v. Includes bibliographical references (leaves 10-12).
22

A multinuclear NMR study of inclusion processes /

Brereton, Ian Malcolm. January 1985 (has links) (PDF)
Thesis (Ph. D.)--University of Adelaide, 1986. / Includes bibliographical references.
23

Properties of magnetic transition metal-bromide graphite intercalation compounds /

Dube, Paul A. January 2002 (has links)
Thesis (Ph.D.) -- McMaster University, 2002. / Includes bibliographical references (leaves 154-163). Also available via World Wide Web.
24

A study of bibracchial lariat ether complexes and linked cyclodextrin dimer complexes /

West, Lee Charles. January 2000 (has links) (PDF)
Thesis (Ph.D.) -- University of Adelaide, Dept. of Chemistry, 2000. / Includes errata attached to first leaf. Includes bibliographical references.
25

Nuclear magnetic resonance studies on clathrate hydrates

Raghunathan, Parthasarathy January 1966 (has links)
With a view to obtaining information on the nature and extent of molecular motion of enclathrated "guests" and their interaction with the "host" lattices, nuclear magnetic resonance absorption of ten guest species included in the clathration voids of fully deuterated hydrates has been studied from a temperature of 77ºK upwards. The F¹⁹ resonance line shapes for CF₄ and SF₆ and the H¹ resonance line shape for ethylene oxide (C₂H₄0) in their respective clathrate hydrates indicate that these molecules are but little restricted by the walls of the clathrate cavities, and reorient freely about chosen axes of symmetry at low temperatures and at random at higher temperatures. Above 150ºK, a limited isotropic translation, or "rattling", of an SF₆ guest molecule up to a distance of [formula omitted] from the centre of the clathration volume has been demonstrated. Proton resonance has been studied for propane in two specimens of the clathrate hydrate, one of which was richer in guest content than the other. For these two specimens it has been suggested that, below 160ºK, propane assumes a staggered C₂ configuration inside the clathrate cavity. Molecular C₂ - axis reorientations superposed on methyl reorientations have been proposed, and a thermal activation energy barrier of 1.70 ± 0.08 kcal/ mole has been calculated for the above motion from spin-lattice relaxation time measurements in the 77ºK - 110°K range. Closer to the melting point of the two specimens, diffusion of propane through the host lattice has been indicated, and diffusional activation energies of 1.40 ± 0.02 kcal/mole and 0.75 ± 0.05 kcal/mole have been obtained for the guest - rich and guest - poor specimens, respectively. In sharp contrast to the above results, the low temperature proton resonance of three halomethanes, CH₃X(X = CI, Br, I), inside hydrate host cavities has revealed definite constraints to reorientational and translational motion, the second moment data indicating only low-amplitude oscillatory motions of the CH₃ groups in these clathrates. A triplet line shape has been observed for the CH₃Br clathrate at 77°K. At higher temperatures, expansion of the hydrate lattices has been proposed, which permits free C₃- reorientations of the CH₃ groups of the three guest molecules. From the associated linewidth transitions, activation energies of 2.48 ± 0.32, 9.30 ± 0.25, and 6.80 ± 0.50 kcal/mole have been calculated for the potential barrier hindering methyl reorientation in the CH₃Cl-, CH₃Br-, and [formula omitted] hydrates, respectively. The motional model proposed for this temperature range is adequately supported by measurements of H¹ spin - lattice relaxation times. For the dichloromethane clathrate hydrate, a clearly resolved doublet characteristic of rigid proton pairs has been obtained at 77°K. The possible existence at low temperatures of an aligned guest molecule in a suitably-sized cavity is thereby indicated. A line shape analysis of this doublet, performed on an IBM 7040 computer, yielded an accurate H-H interatomic distance of 1.73Å for the 'guest' dichloromethane molecule. This value has been discussed in the light of results from earlier microwave studies of dichloromethane. The proton resonance linewidth and second moment results between 77°K and 286°K for i-amyl groups included as guests in the clathrate hydrate of (i-C₅H₁₁)₄NF have been interpreted in terms of simple motional models of these guest moieties. The results complement the reported crystal structure of this clathrate. For the analogous hydrate containing 'guest' n-butyl groups, proton second moments in the same temperature range have supported the disordered guest structure reported from a previous x-ray diffraction study. In addition, hysteresis has been demonstrated in the second moment curve of this clathrate beyond 248°K, and this has been ascribed to a phase transition. / Science, Faculty of / Chemistry, Department of / Graduate
26

NMR study of molecular motions in some clathrate hydrates.

Khanzada, Abdul Wahab Khan January 1970 (has links)
An N.M.R. study of the clathrate hydrates of SF₆, C₃H₆ and (CH₃)₂CO has been carried out to examine the type of motion a guest molecule undergoes in the clathrated cavity. ¹⁹F nuclear magnetic resonance spectra of Sulphur Hexafluoride Hydrate and Deuterate show isotropic rotation or reorientation about an axis at random of the SF₆molecule. ¹H magnetic resonance spectra of Cyclopropane Deuterate show highly restricted rotation up to 240°K, and then free rotation about C₃-axis at high temperatures. ¹H magnetic resonance spectra of Acetone Deuterate show that the CH₃-group is rotating even at 77°K, and self diffusion occurs at 172°K. The barrier hindering diffusion of the (CH₃)₂CO has been calculated and is 3.9 kcal/mole. / Science, Faculty of / Chemistry, Department of / Graduate
27

Structures of Werner clathrates

Papanicolaou, Sevasti January 1983 (has links)
Includes bibliographical references. / X-ray crystallographic studies have been used to elucidate the structures of two new Werner clathrates. ... The chloroform molecule is disordered, lying on a two-fold axis. Stoicheiometric characterization of the clathrates was determined using various chemical techniques, including mass spectroscopy, proton nuclear magnetic resonance and complex iometric titration. The clathrating phase of the second clathrate was investigated by guest-loss studies on a McBain balance followed by X-ray powder photography. Host-quest non-bonded interactions of both clathrate compounds were studied using atom-pair potentials.
28

The structure and rheological properties of liquified natural gas gelled with water and methanol clathrates

Shanes, Lucile Marie January 1977 (has links)
Thesis. 1977. Ph.D.--Massachusetts Institute of Technology. Dept. of Chemical Engineering. / Microfiche copy available in Archives and Science. / Bibliography : leaves 414-426. / by Lucile M. Shanes. / Ph.D.
29

A study of bibracchial lariat ether complexes and linked cyclodextrin dimer complexes

West, Lee Charles. January 2000 (has links) (PDF)
Includes errata attached to first leaf. Includes bibliographical references. The complexation of a range of monovalent and divalent metal ions by the bibracchial lariat ethers has been investigated. Also investigates the complexation of metal ions and the anionic azo dye Brilliant Yellow by the diazacrown linked cyclodextrin dimers.
30

Enhanced Li-ion intercalation properties of vanadium oxides /

Wang, Ying, January 2006 (has links)
Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 156-167).

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