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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.
81

The bioinorganic chemistry of N2S2 metal complexes: reactivity and ligating ability

Golden, Melissa Lynn 29 August 2005 (has links)
[N,N??-bis-(mercaptoethyl)-1,5-diazacyclooctanato]NiII, Ni-1, is known to undergo metallation reactions with numerous metals. [N,N??-bis-(mercaptoethyl)-1,5-diazacycloheptanato]NiII, (bme-dach)Ni or Ni-1??, differs from Ni-1 by one less carbon in its diazacycle backbone ring producing subtle differences in N2S2Ni geometry. Metallation of Ni-1?? with PdCl2, Pd(NO3)2, and NiBr2 produced three structural forms: Ni2Pd basket, Ni4Pd2 C4-paddlewheel, and Ni3 slant chair. In attempts to provide a rationale for the heterogeneity in the active site of Acetyl coA Synthase, metal ion capture studies of Ni-1 in methanol found a qualitative ranking of metal ion preference: Zn2+ < Ni2+ < Cu+. Formation constants for metal ion capture of Ni-1?? in water were determined for Pb2+, Ni2+, Zn2+, Cu+, and Ag+. A quantitative estimate places copper some 15 orders of magnitude above nickel or zinc in binding affinity. Sulfur dioxide uptake by Ni-1?? is characterized by significant color change, improved adduct solubility, and reversible binding of two equivalents of SO2. These combined properties establish Ni-1?? as a suitable model for gas uptake at nickel thiolate sites and as a possibly useful chemical sensor for this poisonous gas. Comparisons of molecular structures, ν(SO) stretching frequencies, and thermal gravimetric analyses are made to reported adducts including the diazacyclooctane derivative, Ni-1·2SO2. Visual SO2 detection limits of Ni-1 and Ni-1?? are established at 25 ppm and 100 ppm, respectively. Structural studies of products resulting from reaction at the nucleophilic S-sites of (bme-dach)Ni and [(bme-dach)Zn]2 included acetyl chloride and sodium iodoacetate as electrophiles are shown. The acetyl group is a natural electrophile important to the citric acid cycle. Acetylation of (bme-dach)Ni produces a five coordinate, paramagnetic species. Iodoacetate is a cysteine modification agent known to inhibit enzymatic activity. The reaction of (bme-dach)Ni and sodium iodoacetate yields a blue, six coordinate nickel complex in a N2S2O2 donor environment. The bismercaptodiazacycloheptane ligand binds lead(II) forming an unprecedented structural form of N2S2M dimers, in which Pb2+ is largely bound to sulfur in a highly distorted trigonal geometry. Its unusual structure is described in comparison to other derivatives of the bme-daco ligand. The synthesis and structural characterization of square pyramidal (bme-dach)GaCl are also given and compared to the analogous (bme-daco)GaCl.
82

The bioinorganic chemistry of N2S2 metal complexes: reactivity and ligating ability

Golden, Melissa Lynn 29 August 2005 (has links)
[N,N??-bis-(mercaptoethyl)-1,5-diazacyclooctanato]NiII, Ni-1, is known to undergo metallation reactions with numerous metals. [N,N??-bis-(mercaptoethyl)-1,5-diazacycloheptanato]NiII, (bme-dach)Ni or Ni-1??, differs from Ni-1 by one less carbon in its diazacycle backbone ring producing subtle differences in N2S2Ni geometry. Metallation of Ni-1?? with PdCl2, Pd(NO3)2, and NiBr2 produced three structural forms: Ni2Pd basket, Ni4Pd2 C4-paddlewheel, and Ni3 slant chair. In attempts to provide a rationale for the heterogeneity in the active site of Acetyl coA Synthase, metal ion capture studies of Ni-1 in methanol found a qualitative ranking of metal ion preference: Zn2+ < Ni2+ < Cu+. Formation constants for metal ion capture of Ni-1?? in water were determined for Pb2+, Ni2+, Zn2+, Cu+, and Ag+. A quantitative estimate places copper some 15 orders of magnitude above nickel or zinc in binding affinity. Sulfur dioxide uptake by Ni-1?? is characterized by significant color change, improved adduct solubility, and reversible binding of two equivalents of SO2. These combined properties establish Ni-1?? as a suitable model for gas uptake at nickel thiolate sites and as a possibly useful chemical sensor for this poisonous gas. Comparisons of molecular structures,&#61472; &#957;(SO) stretching frequencies, and thermal gravimetric analyses are made to reported adducts including the diazacyclooctane derivative, Ni-1&#903;2SO2. Visual SO2 detection limits of Ni-1 and Ni-1?? are established at 25 ppm and 100 ppm, respectively. Structural studies of products resulting from reaction at the nucleophilic S-sites of (bme-dach)Ni and [(bme-dach)Zn]2 included acetyl chloride and sodium iodoacetate as electrophiles are shown. The acetyl group is a natural electrophile important to the citric acid cycle. Acetylation of (bme-dach)Ni produces a five coordinate, paramagnetic species. Iodoacetate is a cysteine modification agent known to inhibit enzymatic activity. The reaction of (bme-dach)Ni and sodium iodoacetate yields a blue, six coordinate nickel complex in a N2S2O2 donor environment. The bismercaptodiazacycloheptane ligand binds lead(II) forming an unprecedented structural form of N2S2M dimers, in which Pb2+ is largely bound to sulfur in a highly distorted trigonal geometry. Its unusual structure is described in comparison to other derivatives of the bme-daco ligand. The synthesis and structural characterization of square pyramidal (bme-dach)GaCl are also given and compared to the analogous (bme-daco)GaCl.
83

Modeled sulfur dioxide exposure from a proposed coal fired power plant, using geographic information systems and air dispersion modeling

Hutchens, Steven Jason. January 2004 (has links)
Thesis (M.S.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains xii, 161 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 132-137).
84

SO₂ removal with coal scrubbing

Sundaram, Hari Prashanth, January 2001 (has links)
Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains vii, 42 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 33-34).
85

The absorption of sulfur dioxide from gases of low concentration

Parkinson, Robert V., January 1953 (has links) (PDF)
Thesis (Ph. D.)--Institute of Paper Chemistry, 1953. / Includes bibliographical references (leaves . 235-239).
86

A thermodynamic study of the system sodium sulfite-sodium bisulfite-water at 25⁰C

Morgan, Robert S., January 1960 (has links) (PDF)
Thesis (Ph. D.)--Institute of Paper Chemistry, 1960. / Includes bibliographical references (leaves 72-73).
87

Measuring SO₂ emissions from Mt. Etna (Italy) using a network of scanning ultraviolet spectrometers

Salerno, Giuseppe Giovanni January 2012 (has links)
No description available.
88

Fuel sulfur effects on No(x) formation in turbulent diffusion flames

Corley, Timothy Lynn January 1976 (has links)
Interactions between certain fuel sulfur compounds and nitric oxide (NO) in turbulent gaseous and distillate oill diffusion flames were experimentally investigated utilizing a 75,000 Btu/hr laboratory combustor. Aerodynamics, air preheat conditions, and overall excess air conditions were varied to determine their role on any such interaction. Results indicated that addition of sulfur dioxide (SO₂) to natural gas flames could enhance or inhibit NO emissions. Local flame stoichiometry and temperature, which were influenced by fuel injector type, determined which effect was observed and the extent to which it occurred. Thiophen (C₄H₄S) and pyridine (C₅H₅N) were added to #2 diesel oil to determine effects of fuel sulfur on conversion of chemically bound fuel nitrogen to No. No discernible effect was observed at "zero" air preheat conditions. No emissions were enhanced at high air preheat conditions. Addition of SO₂ to natural gas flames doped with ammonia (NH₃) produced a significant increase in conversion of NH₃ to NO at high air preheat conditions. Inhibition effects were explained in terms of homogeneous catalysis of recombination reactions by SO₂. Hydrogen abstraction reactions involving reduced sulfur species and other oxidation reactions involving SO₂, or a reduced form, were considered to explain the enhancement effect.
89

Kinetic study of low temperature sulfur dioxide and hydrogen chloride removal using calcium-based sorbents

Zhan, Rijing. January 1999 (has links)
Thesis (Ph. D.)--Ohio University, November, 1999. / Title from PDF t.p.
90

Dietary antioxidants and ozone-induced bronchial hyperresponsiveness in asthmatic adults /

Trenga, Carol A. January 1997 (has links)
Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [78]-91).

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