UNT Theses and Dissertations - 609 Matching Results

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Naphthoquinone Studies

Description: This thesis describes a series of naphthoquinone reactions employing pyridine carboxylic acid derivatives (nicotinic acid derivatives). The products of these reactions will be tested by Parke, Davis and Company for their activity against the tubercle bacillus and other pathogenic microorganisms.
Date: 1955
Creator: Padgett, William A.
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The Nature of Intermediates Produced Through Ligand-Substitution Reactions of Octahedral Metal Carbonyls

Description: Pulsed laser time-resolved ligand-substitution photochemistry for (DTO)W(CO)4, (DTN)W(CO)4, and (NP)Mo(CO)4 (DTO = 2,2,7,7-tetramethyl-3,6-diathiaoctane; DTN = 2,2,8,8- tetramethyl-3,7-diathianonane; NP = l-diethylamino-2- diphenylphosphinoethane) proceeds via initial fission of the W-S and Mo-P bonds, affording Cs and C4v five-coordinate intermediates for DTN and NP but largely Cs for DTO. The rates of reaction of these intermediates, via chelate ring closure and competitive bimolecular intera… more
Date: May 1986
Creator: Mansour, Saber E. (Saber El-Sayed)
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Nitration of Thiophene Analogs of DDT

Description: Since thiophene very often yields compounds that are analogous to benzene derivatives in general physiological properties, it was decided to attempt to prepare the nitro and amino derivatives of 1,1,1-trichloro-2,2-bis-(2-thienyl)-ethane (V) as well as the nitro and amino derivatives of 2,2,3-trichloro-1,1-bis-(2-thienyl)-butane (VI).
Date: February 1953
Creator: Buttram, Jack Rhea
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Nitrogen Derivatives of Naphthoquinone

Description: A series of nitrogen derivatives of 1,4-naphthoquinone, which are structurally similar to the compounds of Hall, has been prepared by this worker. In general, the amido groups are those of the long-chain, fatty acids, and it is believed they will have increased physiological activity. These compounds are to be tested for medicinal activity by Parke-Davis and Company.
Date: June 1953
Creator: Wood, Frank M.
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Nitrogen Reduction Reaction: Deposition, Characterization and Selectivity of Transition Metal (V, Co and Ti) Oxynitrides as Electrocatalysts

Description: The electrocatalytic nitrogen reduction reaction (NRR) is of considerable interest due to its potential for less energy intensive and environmentally friendly ammonia production which is critical for agricultural and clean energy applications. However, the selectivity of NRR compared to the hydrogen evolution reaction (HER) often poses challenges for various catalysts, including Earth-abundant transition metal oxynitrides like Ti, V, and Co. In this work, a comparative analysis of the selectivi… more
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Date: December 2023
Creator: Chukwunenye, Precious O.
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An NMR Investigation of Aryl Mercury Compounds

Description: A variable temperature ^13 C and ^199 Hg NMR study has been conducted for diphenyl-, bis(o-tolyl)-, bis(m-tolyl)-, and bis(2, 6-xylyl)mercury in dimethyl sulfoxide and 1,1,2,2 tetrachloroethane; ^13 C T1 relaxation times are reported as a function of temperature. Barriers to rotation of the aryl rings are obtained. Chemical shifts and couplings in CDCl_3 are given for bis(p-tolyl)-, bis(2, 5-xylyl)-, bis(mesityl)-,phenyl(o-tolyl)-, phenyl(m-tolyl)mercury, and the compounds listed above. The ste… more
Date: May 1987
Creator: Rowland, Keith E. (Keith Edward)
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An NMR study of 2-ethyl-1-butyllithium and of 2-ethyl-1-butyllithium/lithium 2-ethyl-1-butoxide mixed aggregates

Description: A 1H, 13C, and 6Li NMR study of 2-ethyl-1-butyllithium indicated that 2-ethyl-1-butyllithium exists only as a hexameric aggregate over the entire temperature range of 25 to - 92.1 ° C in cyclopentane. Reacting 2-ethyl-1-butyllithium with 2-ethyl-1-butanol resulted in alkyllithium/lithium alkoxide mixed aggregates, apparently of the form Ra(RO)bLia+b. A multinuclear, variable temperature NMR study of samples with O:Li ratios of 0.2 and 0.4 showed, in addition to the alkyllithium, the formation o… more
Date: May 2001
Creator: Ferreira, Aluisio V. C.
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NMR study of 2-ethylhexyllithium aggregate and 2- ethylhexyllithium/lithium 2-ethyl-1-hexoxide mixed aggregates.

Description: A 1H, 13C, and 6Li NMR study of 2-ethylhexyllithium showed that 2- ethylhexyllithium exists solely as a hexamer in cyclopentane solution over the temperature range from 25 to -65 °C. Furthermore, 2-ethylhexyllithium and lithium 2- ethyl-1-hexoxide were shown to form mixed aggregates when the alkoxide was formed in situ by reacting 2-ethylhexyllithium with 2-ethyl-1-hexanol. A multinuclear, variable temperature NMR study of a sample with an O:Li ratio of 0.2 led to the identification of at least… more
Date: December 2001
Creator: Petros, Robby A.
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NMR Study of n-Propyllithium Aggregates

Description: A variable temperature 1H, 13C, and 6Li NMR study of n-propyl-6Li-lithium showed five different aggregates, similar to that in the literature as (RLi)n, n= 6, 8, 9, 9, 9. There were also a number of additional new species, identified as lithium hydride containing aggregates. Unexpectedly, a series of 13C{1H} 1-D NMR experiments with selective 6Li decoupling showed evidence for 13C-6Li spin-spin coupling between the previously reported (RLi)n aggregates and various hydride species.
Date: December 2002
Creator: Davis, James W.
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NMR Study of the Reorientational and Exchange Dynamics of Organometallic Complexes

Description: Investigations presented here are (a) the study of reorientational dynamics and internal rotation in transition metal complexes by NMR relaxation experiments, and (b) the study of ligand exchange dynamics in transition metal complexes by exchange NMR experiments. The phenyl ring rotation in Ru3(CO)9(μ3-CO)(μ3-NPh) and Re(Co)2(CO)10(μ3- CPh) was monitored by 13C NMR relaxation experiments to probe intramolecular electronic and/or steric interactions. It was found that the rotation is relatively … more
Date: May 1996
Creator: Wang, Dongqing
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Novel LC-MS Method for the Analysis of Beta-Hydroxybutyric Acid (BHB) in Health Formulations

Description: The rise of nutraceutical health formulations has increased the need for more stringent analytical testing methods. Complex matrices present a new problem when determining concentration of compounds of interest. The presented method uses LC-MS analysis with a novel sample preparation method in the determination of Beta-hydroxybutyric acid in health formulations. The use of an aqueous analytical column allows for separations of polar compounds after non-polar compounds are removed through C18 pa… more
Date: May 2022
Creator: Smith, Garret Mackenzie
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Novel Metal-Containing Nanoparticle Composites for Cancer Therapy and Imaging

Description: With all the improvements in cancer treatments, multidrug resistance is still the major challenge in treating cancer. Cells can develop multidrug resistance (MDR) during or after treatment, which will render the cancer cells resistant not only to the chemotherapy drug being used but also to many other structurally- and mechanically-different chemotherapeutics. In the first project, the main focus was on development of drug resistant cell lines by selection with taxol. Gene changes in the L1T2 c… more
Date: August 2020
Creator: Nasiri, Nooshin Mirza
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Nuclear Magnetic Resonance Spectra of Some 1,2,4-triazoles

Description: In the work undertaken here, NMR has been used to ascertain the structure of some 1,2,4-triazoles. The investigation provides information concerning the structure of potentially tautomeric triazoles such as hydroxy- and aminotriazole. Connected with this aspect of triazole chemistry is the larger problem of mesohydric tautomerism. The present study also yields information for a comparison of substituent effects in triazoles, N-heteroaromatic substances and benzene.
Date: January 1967
Creator: Creagh, Linda Truitt
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I. On the Mechanism of Acid Promoted Rearrangement of PCU-Derived Pinacols II. Synthesis of a Trimethyltrishomocubyl Helical Tubuland Diol

Description: I. Reductive dimerization of pentacyclo[5.4.0.0.^2,6.0^3,10.0^5'9]undecane-8-one-(PCU-8-one, 53) affords a mixture of meso and d,l pinacols (55a and 55b respectively). Acid promoted rearrangement of 55a and 55b conceivably can proceed with migration of C(7)-C(8) and/or C(8)-C(9) to form the corresponding pinacolone(s). In our hands, acid promoted rearrangement of 55a and 55b each proceeds with exclusive migration of C(7)- C(8) bond, thereby affording 58a and 59a respectively. Mechanistic featur… more
Date: May 1995
Creator: Liu, Zenghui
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One-Step Synthesis of 1,3,4-Oxadiazines, 4,5,6,7-Tetrahydro-1h-Indoles, and Functionalized Benzo[B]Carbazoles Catalyzed by Rare Earth Metal Triflates and Cooperative Enamine-Bronsted Acid

Description: Design and development of novel one-step reactions that produce nitrogen-containing scaffolds is an invaluable area of chemistry due to the abundance of these moieties in natural products and biologically active molecules. Discovering novel methods using uncommon substrates and rare earth metals to access these significant scaffolds present a challenge. Over the course of my doctoral studies, I have designed, developed and optimized novel reactions by using rarely known substrates and rare eart… more
Date: May 2023
Creator: Cortes Vazquez, Jose
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Optimization of High Performance Liquid Chromatographic Separations

Description: This study had a twofold purpose. First, the usefulness of the simplex algorithm as a short method of optimization in high performance liquid chromatographic separations was investigated. The second was to test a modified simplex method. The volume fractions of mobile phase components were chosen as the variable factors in the optimization process. Four test cases were performed which included separation of cholesterol esters, naphthalene and its derivatives, polycyclic aromatic compounds, and … more
Date: August 1983
Creator: Nguyen, Khanh Thi
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Optoelectronically Active Metal-Inorganic Frameworks and Supramolecular Extended Solids

Description: Metal-organic frameworks (MOFs) have been intensely researched over the past 20 years. In this dissertation, metal-inorganic frameworks (MIFs), a new class of porous and nonporous materials using inorganic complexes as linkers, in lieu of traditional organic linkers in MOFs is reported. Besides novel MIF regimes, the previously described fluorous MOF "FMOF-1", is re-categorized herein as "F-MIF1". F-MIF-1 is comprised of [Ag4Tz6]2- (Tz = 3,5-bis-trifluoromethyl-1,2,4-triazolate) inorganic clust… more
Date: August 2018
Creator: Ivy, Joshua F.
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Organelle- and Organ-Specific Isozymes of Euglena Gracilis and Catfish

Description: Two distinct compartmentalized isozymes of aldolase and triosephosphate isomerase were examined in the photoautotrophically and heterotrophically grown green alga Euglena gracilis. A comparison of the chemical and physical properties of the isozymes was carried out. Isozymes of phosphoglucose isomerase were isolated in homogeneous form from liver and muscle tissue of the fresh water catfish. The two organ-specific isozymes were essentially identical with respect to their molecular weights but e… more
Date: December 1974
Creator: Mo, Yeh-Chun
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Organomagnesium Compounds in Benzene Solvent and Their Application in Synthesis of Organoberyllium Compounds

Description: The work reported by D. Bryce-Smith and G. F. Cox, along with several recent publications describing experimental results designed to elucidate the long disputed question of the structure of the Grignard reagent in ether stimulated the work reported here, in an effort to obtain additional evidence of the structure of the organomagnesium complex in benzene solvent. Since the primary objective of this work was to prepare organoberyllium compounds using the organomagnesium complexes in hydrocarbon… more
Date: January 1966
Creator: Selman, Charles M.
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Organometallic Precursors to Cyclic Organosilanes

Description: This investigation deals with the preparations of cyclic organosilanes via two different types of organometallic precursors: borane adducts to chlorovinylsilanes and tertbutyllithium adducts to chlorovinylsilanes. The regiospecificity of the hydroboration of various types of boranes to chlorovinylsilanes was studied by three different methods. It was found that, by using bulky hydroborating agents, about 80% isomerically pure terminal borane adducts to chlorovinylsilanes could be obtained. Whil… more
Date: May 1977
Creator: Lim, Thomas Fay-Oy
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Oxovanadium(IV) Complexes of Substituted N-(2-Thiophenyl)Salicylideneimine

Description: In an effort to study the spectral, magnetic, and stereochemical properties of vanadyl complexes, both a new series of vanadyl complexes derived from type (VII) ligands with subnormal magnetic moment and from type (VIII) ligands with normal magnetic moment are synthesized and characterized.
Date: June 1970
Creator: Lee, Cheng Chang
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