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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.
31

The chemistry of tetraosmium carbonyl clusters /

Choi, Ya-yin. January 1998 (has links)
Thesis (Ph. D.)--University of Hong Kong, 1998. / Includes bibliographical references.
32

Osmium isotope geochemistry of terrigenous and marine sediments

Esser, Bradley Keith. January 1900 (has links)
Thesis (Ph. D.)--Yale University, 1991. / Includes bibliographical references (p. 283-308).
33

New neutron deficient radioactive isotopes of rare earths and osmium

Jones, Betsy Mae, January 1900 (has links)
Thesis (Ph. D.)--University of California, June 1950. / Also issued as UCRL [i.e. Univ. of California Radiation Laboratory] 656. Bibliography: p. 20.
34

Growth and characterization of ß-iron disilicide , ß-iron silicon germanide, and osmium silicides

Cottier, Ryan James. Littler, Christopher Leslie, January 2009 (has links)
Thesis (Ph. D.)--University of North Texas, Dec., 2009. / Title from title page display. Includes bibliographical references.
35

Fluorosulfates of silver, ruthenium, and osium

Leung, Patrick Cheung Shing January 1979 (has links)
A number of synthetic routes to silver(II) fluorosulfate, Ag(SO₃F)₂, were systematically explored. The most suitable and versatile route was found to be the oxidation of silver metal by a solution of bisfluorosulfuryl peroxide, S₂0₆F₂, in fluorosulfuric acid, HSO₃F, according to: [chemical reaction] Additional methods which were found to be suitable involved the oxidation of a wide variety of silver(I) compounds such as Ag₂0 or AgSO₃F by S₂O₆F₂' or the insertion of S0₃ into AgF₂. Structural conclusions on Ag(S0₃F)₂ and the other compounds synthesized subsequently were based on the vibrational, electronic and electron spin resonance spectra, as well as on magnetic susceptibility measurements made between 300 and 77 K. Ag(S0₃F) ₂was found to be a true compound of divalent silver, with the Ag²⁺ ions in either square planar or tetragonally elongated octahedral environment. The only other example of a binary silver(II) compound is AgF₂. and characterized. The reactions of bromine(I) fluorosulfate with metallic silver and other silver(I) substrates resulted in a mixed valence complex Ag[sup I]Ag[sup II](SO₃F)₄ . Its potassium analogue K₂AgCSO₃F)₄, as well as two hexakisfluorosulfato- metallate (IV) complexes AgPt[sup= IV] (SO₃F)₆ , and AgSn[sup= IV] (SO₃F)₆, and the N-donor ligand complex [Ag(bipy)₂l (SO₃F)₂ (i-n which bipy = 2,2'-bipyridine) were also synthesized. The attempt to synthesize a silver(III) fluorosulfato complex by direct insertion of SO₃ into CsAgF₄ resulted in the fluorination of SO₃, to give S₂O₆F₂ and CsAg(SO₃F)₃. Finally, the solvolysi of Ag(SO₃F)₂ in trifluoromethylsulfuric acid, HSO₃CF₃, allowed its conversion into Ag(SO₃F₃). The principal synthetic route, the oxidation of metal by S₂O₆F₂ solutions in HSO₃F, was found to be useful in the preparation of Ru(SO₃F)₃. Ruthenium was also found to form a number of anionic derivatives with the metal in the +3 or +4 oxidation state, as in M[Ru(SO₃F)₄] with M = Cs⁺, ClO₂⁺ ; M₂[Ru(SO₃F)₆ with M = Cs⁺, K⁺; and Cs[Ru(SO₃F)₅]. Two different forms of Os(SO₃F)₃ were found. Initial oxidation of osmium metal with S₂O₆F₂ yielded the bright green a-Os(SO₃F)₃, which was converted to the light green β-form on long standing in S₂O₆F₂. / Science, Faculty of / Chemistry, Department of / Graduate
36

Reaction of tryptophan derivatives and lysozyme with the osmium tetroxide-pyridine reagent /

Deetz, Jeffrey Scott January 1980 (has links)
No description available.
37

Pair-specific osmium reagents for polynucleotides /

Ford, Harry January 1980 (has links)
No description available.
38

Synthesis of anionic and neutral derivatives of H₂Os₃(CO)₁₀.

Kennedy, Steven January 1981 (has links)
No description available.
39

Synthesis and characterization of diphosphine ligand substituted osmium and ruthenium clusters.

Kandala, Srikanth 08 1900 (has links)
The kinetics for the bridge-to-chelate isomerization of the dppe ligand in H4Ru4(CO)10(dppe) have been investigated by UV-vis and NMR spectroscopies over the temperature range of 308-328 K. The isomerization of the ligand-bridged cluster 1,2-H4Ru4(CO)10(dppe) was found to be reversible by 31P NMR spectroscopy, affording a Keq = 15.7 at 323 K in favor of the chelating dppe isomer. The forward (k1) and reverse (k-1) first-order rate constants for the reaction have been measured in different solvents and in the presence of ligand trapping agents (CO and PPh3). On the basis of the activation parameters and reaction rates that are unaffected by added CO and PPh3, a sequence involving the nondissociative migration of a phosphine moiety and two CO groups between basal ruthenium centers is proposed and discussed. The substitution of the MeCN ligands in the activated cluster 1,2-Os3(CO)10(MeCN)2 by the diphosphine ligands dppbz proceeds rapidly at room temperature to furnish a mixture of bridging and chelating Os3(CO)10(dppbz) isomers and the ortho-metalated product HOs3(CO)9[μ-(PPh2)C=C{PPh(C6H4)}C4H4]. Thermolysis of the bridging isomer 1,2-Os3(CO)10(dppbz) under mild conditions gives the chelating isomer 1,1-Os3(CO)10(dppbz), molecular structure of both the isomers have been determined by X-ray crystallography. The kinetics for the ligand isomerization has been investigated by UV-vis and 1H NMR spectroscopy in toluene solution over the temperature range of 318-343 K. On the basis of kinetic data conducted in the presence of added CO and the Eyring activation parameters, a non-dissociative phosphine migration across one of the Os-Os bonds is proposed. Ortho metalation of one of the phenyl groups associated with the dppbz ligand is triggered by near-UV photolysis of the chelating cluster 1,1-Os3(CO)10(dppbz). The triosmium cluster 1,2-Os3(CO)10(MeCN)2 reacts with the diphosphine ligand 3,4­bis(diphenylphosphino)-5-methoxy-2(5)H-furanone (bmf) at 25 ºC to give the bmf-bridged cluster 1,2-Os3(CO)10(bmf). Heating 1,2-Os3(CO)10(bmf) leads to an equilibrium with the chelating isomer 1,1-Os3(CO)10(bmf). The molecular structure of each isomer has been crystallographically determined, and the kinetics for the isomerization has been investigated by UV-vis and 1H NMR spectroscopy. The reversible nature of the diphosphine isomerization has been confirmed by NMR measurements, and the forward (k1) and reverse (k-1) first-order rate constants for the bridge-to-chelate isomerization have been determined. Thermolysis of the SEQ CHAPTER h r 11,1-Os3(CO)10(bmf) cluster (>110 ºC) leads to regiospecific activation of C-H and P-C bonds, producing the hydrido clusters HOs3(CO)9[µ-PPh2C=C{PPh(C6H4)} CH(OMe)OC(O)] and the benzyne clusters HOs3(CO)8(μ3-C6H4)[µ-PPhC=C(PPh2)CH(OMe)OC(O)]. The hydride and benzyne clusters, which exist as a pair of diastereomers, have been fully characterized in solution by IR and NMR spectroscopy, and the molecular structure of one benzyne cluster (major diastereomer) has been determined by X-ray crystallography.
40

High-valent ruthenium and osmium oxo complexes for homogeneous and photochemical oxidations of inorganic and organic substrates

任詠華, Yam, Wing-wah, Vivian. January 1988 (has links)
published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

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