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Syllabus Outline for Genetics Lecture and Laboratory
This work is intended to be used as a teaching tool in conjunction with the text cited. It is written in outline format, highlighting the major concepts of each pertinent chapter. In this format, the concepts can be expanded upon at the discretion of the instructor. This work is to be used as a guide for lecture. The basic concepts contained in the outline are in such a format as to be able to work in more information regarding the subject matter if needed. The instructor can work from this outline as a starting point. Major topics in the chapters are highlighted, making lecture notes for the instructor easier to do. digital.library.unt.edu/ark:/67531/metadc2241/
The Symbolic Representation of Latinos: A Content Analysis of Prime-Time Television
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The media are powerful agents of socialization in modern society influencing values, beliefs, and attitudes of the culture that produces them. Both the quantity and quality of Latino images in the media may reflect and reinforce the place of Latinos in United States society. This study examines how Latinos are portrayed in television entertainment programming by addressing two major research questions: 1) What is the extent of Latino recognition on prime-time television? and 2) What is the extent of respect accorded Latinos on prime-time television? A one-week sample of prime-time television programming airing on three networks yielded 47 programs and 807 characters for analysis. Using content analysis methodology, recognition is identified by examining the frequency and proportional representation of Latino television portrayals and respect is measured by examining the types and significance of these roles. The results indicate an overall lack of diversity on prime-time television with only 11 of the 47 programs analyzed reaching 50% or more of the maximum possible diversity in their racial and ethnic portrayals. Specifically, Latinos represent only 3% of primetime television characters, less than one-fourth of their proportion of the nation's population. Compared to non-Hispanic Whites, Blacks, and Asians, Latinos are the group least likely to occupy major roles in prime-time entertainment shows and represent only 1.9% of the total opening cast credits. Latinos are still presented stereotypically but are more often presented in a generic fashion with no reference to ethnic cultural experiences. The extent of recognition and respect accorded Latinos in prime-time television is severely limited, thus there is a need for continued research and dialogue regarding symbolic media images of Latinos. The findings have implications for social scientists interested in media forms and content as cultural artifacts, members of the television media industry responsible for program development and distribution, and college media educators responsible for training young media professionals. digital.library.unt.edu/ark:/67531/metadc2838/
Symbolic visuals in advertising: The role of relevance.
Relevance has been applied to various conditions in the marketing literature but no single definition has been developed. A single clear definition will be helpful to researchers investigating relevance in the marketing and consumer behavior fields. Confusion also exists in the literature regarding to what extent a symbolic visual in an advertisement is relevant. Many researchers are also calling for empirical evidence of a linkage between relevance and response through a theoretical measure of relevance. The central theory used in this dissertation is Sperber and Wilson's (1995) theory of relevance (TOR). TOR can help researchers and marketing managers by explaining how consumers may interpret visuals in advertising. TOR explains why some visuals thought to be unconnected with the product become relevant in advertising. This study makes the assertion that TOR has been underutilized and even ignored by some researchers in past marketing literature. Thus, TOR is used to provide greater explanatory power of consumers' interpretation and response to advertising visuals than what is currently realized by researchers and marketing managers. A reliable measure of relevance was developed using TOR as a foundation. Experiments were conducted to empirically test TOR and support was found for most aspects of the theory. This dissertation makes several contributions to the consumer behavior literature. These contributions include: 1) clarifying the definition of relevance in advertising, 2) developing a tentative measure of relevance, 3) providing an explanation of how non-relevant visuals produce effects expected for relevant visuals as occurred in experiments conducted by Mitchell and Olson (1981) and Miniard, Bhatla, Lord, Dickson and Unnava (1991), 4) showing how relevance of symbolic visuals in advertisements relates to specific consumer responses, and 5) offering suggestions for how the theory of relevance can be used by researchers and marketing managers to gain a better understanding of consumers' interpretation of advertising visuals. digital.library.unt.edu/ark:/67531/metadc9089/
Symbolism in Leaves of Grass
This thesis discusses the symbolism found in Walt Whitman's second poetic period, as found in the collection Leaves of Grass. digital.library.unt.edu/ark:/67531/metadc75507/
Symbolism in Six Works of Joseph Conrad
This study examines evidence as to Conrad's principles provided by the symbolism in five novels and one novelette. digital.library.unt.edu/ark:/67531/metadc83642/
Symmetrical Features of Nikolai Medtner's Language: The Grzovaya Sonata, Opus 53 No. 2
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Nikolai Medtner's works evidence an intense interest in symmetrical designs. This concern is manifest at all levels, from the large scale proportions of his numerous ingenious sonata forms to the symmetrically constructed themes and motives. Medtner's works include several instances of palindromic themes and periods. Some palindromic contours are achieved through immediate inversion, creating expansive, symmetrical waves. One of Medtner's thumbprints, symmetrical contrary voice-leading, consists of two or more voices which systematically expand or contract in exact mirror fashion. The contrary movement is usually stepwise, and may be either chromatic or diatonic. Occasionally even larger intervals, such as thirds and fourths, are subjected to this favourite mirroring technique. Such symmetrical expansion and contraction often controls the harmonic progression of several consecutive bars. One of the most striking aspects of Medtner's music is his sophisticated harmonic language. He was fascinated with symmetrical harmonic designs, such as the tritone, the French sixth chord, and the octatonic scale, and made endless and increasingly intricate explorations into these stuctures and the ways in which these apparently nontonal, non-hierarchical forms could be coordinated with the fundamental hierarchy of asymmetrical tonal forms, including triads, major and minor scales, and tonic-dominant relations. Medtner's late work, the Grozovaya Sonata, Opus 53 No.2, is the most concentrated and abstract of his works. The themes are built from highly lapidar motives, giving this work an intensely angular, rigorously mathematical character. All the symmetrical hallmarks of Medtner's language are in abundant evidence in this great work. Features include the extensive symmetrical mirroring of the opening section, frequent use of contrary voice leading as a generator of harmonic progression, and constant tritone shifting. Medtner also builds sequential chains based on two more symmetrical forms, the diminished seventh and the augmented triad. Finally, the design of this unique single movement sonata may be a hybrid of sonata form with palindrome. The Grozovaya Sonata is a microcosm of the symmetrical features of Medtner's language. digital.library.unt.edu/ark:/67531/metadc2271/
Symphonic Fantasia Han-Kook Oui Ja-Yeon (Nature in Korea): Score and Critical Commentary
The Symphonic Fantasia Han-Kook oui Ja-Yeon (Nature in Korea ) is a single-movement orchestral piece, which is divided into 5 characteristic sections - each section has programmatic subtitles (Rocks, River, Sea, Wind, and Mountain) and its own idée fixe motive. The degree of texture (homophonic/polyphonic), dynamics (strong/weak), density (thick/thin), velocity (fast/slow), and orchestration (emphasizing various sections of the orchestra) is determined by depiction of the subtitles. The critical commentary of the Symphonic Fantasia Han-Kook oui Ja-Yeon (Nature in Korea ) includes a discussion of form, pitch content (melodic and harmonic), and texture of the piece. The commentary also includes a discussion of the use of programmatic subtitles (Rocks, River, Sea, Wind, and Mountain) and depiction of these concepts in the orchestration of the work. A comparison with other orchestral works is added for explanation and support of the composer's concept. Some of the other composers who are discussed in this paper include Richard Strauss (Alpine Symphony), Gustav Holst (The Planets), Frank Bridge (The Sea), Aaron Copland (Billy the Kid), and Joseph Klein (Pathways: Interior Shadows). digital.library.unt.edu/ark:/67531/metadc4612/
Symphony No. 1
Symphony No. 1 is an orchestral composition for twenty-four instrumental groups without percussion instruments. It was composed with Algorithmic Composition System software, which gives driving forces for composition to the composer through the diverse compositional methods largely based on physical phenomena. The symphony consists of three movements. It lasts about sixteen minutes and twenty-six seconds--five minutes and twenty-two seconds for the first movement, five minutes and forty seconds for the second movement, five minutes and twenty-four seconds for the third movement. Most musical components in the first movement of the symphony are considered embryos, which gradually begin developing through the second and third movements. digital.library.unt.edu/ark:/67531/metadc2815/
Symptoms of anxiety and depression in children and adolescents: The impact of residential fire.
This study examined symptoms of anxiety and depression in 99 children and adolescents following a residential fire. Children and their parents completed self-administered questionnaires regarding the fire and their current functioning. The most commonly experienced symptoms were worry/ oversensitivity, anhedonia, negative mood, and fear of failure and criticism. There were no significant ethnic differences across symptomology. Exposure was directly related to parental report of child internalizing behaviors, whereas loss was unrelated to symptoms. Level of support (general and fire related) and active coping were directly associated with positive child adjustment. The impact of negative life events was related to poorer functioning. Overall, a child's environment and coping strategy appear to be the best predictors of adjustment following a residential fire. digital.library.unt.edu/ark:/67531/metadc4339/
Syncretisms for wind quintet and percussion: A study in combining organizational principles from Southeast Asian music with western stylistic elements.
Syncretisms is an original composition scored for flute, oboe, clarinet, horn, bassoon, and marimba (2-mallet minimum, 4 recommended) with an optional percussion part requiring glockenspiel and chimes, and has an approximate duration of 6 min. 45. sec. The composition combines modern western tuning, timbre, and harmonic language with organizational principles identified in music from Southeast Asia (including music from cultures found in Thailand, Cambodia, Malaysia, and Indonesia). The accompanying paper describes each of these organizational principles, drawing on the work of scholars who have performed fieldwork, and describes the way in which each principle was employed in Syncretisms. The conclusion speculates on a method for comparing musical organizational systems cross-culturally. digital.library.unt.edu/ark:/67531/metadc6055/
The Syntheses of Amino Substituted Salicylic Acids and Related Compounds
The introduction of the ether linkage into various compounds imparts physiological activity, hence the synthesis of various ether derivatives involving the phenol group seemed to be a possible route to tuberculostatic substances. The compounds reported in this work are to be tested for tuberculostatic properties by Parke, Davis and Company. digital.library.unt.edu/ark:/67531/metadc83557/
Syntheses, X-ray Diffraction Structures, and Kinetics on New Formamidinate-Substituted Triosmium Clusters
The reaction between the formamidine ligand PriN=CHNHPri and the activated cluster Os3(CO)10(MeCN)2 has been studied. A rapid reaction is observed at room temperature, yielding the hydride clusters HOs3(CO)9[μ-OCNPriC(H)NPri] and HOs3(CO)10[μ-NPriC(H)NPri] as the principal products. The spectroscopic data and X-ray diffraction structures of those formamidinate-substituted clusters will be present. The thermal reactivity of the clusters has been investigated, with the face-capped cluster HOs3(CO)9[μ-NPriC(H)NPri] found as the sole observable product. The relationship between these three clusters has been established by kinetic studies, the results of which will be discussed. digital.library.unt.edu/ark:/67531/metadc33217/
Synthesis and Characterization of 2,3-Dichloropyrrolo[1,2-a]benzimidazol-1-one and Its Methylthiol Derivatives
Condensation of 2,3-dichloromaleic anhydride and o-phenylenediamine in refluxing toluene affords the three compounds 2,3-dichloro-N-o-C6H4(NH2)maleimide (1), N,N¢-o-C6H4-bis(2,3-dichloromaleimide) (2), and 2,3-dichloropyrrolo[1,2-a]benzimidazol-1-one (3), with compound 1 as the major product. Repeating the same reaction in the presence of added PTSA furnishes compound 3 as the major product. Treatment of 3 with methylthiol in the presence of pyridine affords monosulfide compounds 2-chloro-3-methylthiopyrrolo[1,2-a]benzimidazol-1-one (4) and and the disulfide derivatives 2,3-di(methylthio)pyrrolo[1,2-a]benzimidazol-1-one (5). The substitution of the first chlorine group in compound 3 occurs regioselectively at C-3 to produce compound 4, followed by replacement of the remaining chlorine group to furnish the disulfide compounds 5. The new compounds 1-5 have been isolated by column chromatography and characterized by IR, NMR, XRD, CV and etc. digital.library.unt.edu/ark:/67531/metadc5238/
Synthesis and characterization of 2-chloro-3-benzylthiopyrrolo[1,2-a]- benzimidazol-1-one and 2,3-di(benzylthio)pyrrolo[1,2-a]benzimidazol-1-one.
The reaction between o-phenylenediamine and 2,3-dichloromaleic anhydride has been probed and found to give 2,3-dichloropyrrolo[1,2-a]- benzimidazol-1-one as the major product. Chlorine substitution in 2,3-dichloropyrrolo[1,2-a]benzimidazol-1-one by added benzylthiol occurs in the presence of pyridine to provide the corresponding monosulfide and disulfide derivatives. The first benzylthiol ligand undergoes reaction at the C-3 position of the five-membered pyrrolo-1-one ring, with the addition of the second benzylthiol ligand occurring at the remaining chlorine-substituted carbon. The mono- and disulfide derivatives have been isolated and characterized in solution by NMR, IR, and UV-vis spectroscopies, and the solid-state structure of 2,3-di(benzylthio)pyrrolo[1,2-a]benzimidazol-1-one has been established by X-ray crystallography. digital.library.unt.edu/ark:/67531/metadc4415/
Synthesis and Characterization of Copper Releasing Polymer Nanoparticles
Polymeric nanoparticles were synthesized and loaded with Cu²⁺ to explore the therapeutic potential for catically active transition metal ions and complexes other than cisplatin. Two types of nanoparticles were synthesized to show the potential for polymer based vectors. Copper loading and release were characterized via inductively coupled plasma mass spectrometry (ICP MS), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and elemental analysis. Results demonstrated that Cu could be loaded to the nano-sized carriers in an aqueous environment, and that the release was pH-dependent. The toxicity of these particles was measured in HeLa cells where significant toxicity was observed in vitro via dosing of high Cu-loaded nanoparticles. No significant toxicity was observed in cells dosed with Cu-free nanoparticles. digital.library.unt.edu/ark:/67531/metadc67990/
Synthesis and Characterization of Crystalline Assemblies of Functionalized Hydrogel Nanoparticles
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Two series monodispersed nanoparticles of hydroxylpropyl cellulose (HPC) and functionalized poly-N-isopropylamide (PNIPAM) particles have been synthesized and used as building blocks for creating three-dimensional networks, with two levels of structural hierarchy. The first level is HPC nanoparticles were made from methacrylated or degradable cross-linker attached HPC. These nanoparticles could be stabilized at room temperature by residual methacrylate or degradable groups are present both within and on the exterior of HPC nanoparticles. Controlled release studies have been performed on the particle and networks .The nearly monodispersed nanoparticles have been synthesized on the basis of a natural polymer of hydropropylcellulose (HPC) with a high molecular weight using the precipitation polymerization method and self-assembly of these particles in water results in bright colors. The HPC nanoparticles can be potential using as crosslinkers to increase the hydrogels mechanical properties, such as high transparency and rapid swelling/de-swelling kinetics. The central idea is to prepare colloidal particles containing C=C bonds and to use them as monomers - vinylparticles, to form stable particle assemblies with various architectures. This is accomplished by mixing an aqueous suspension of hydrogel nanoparticles (PNIPAM-co-allylamine) with the organic solvent (dichloromethane) to grow columnar crystals. The hydrogels with such a unique crystal structure behavior not only like the hydrogel opals, but also have a unique property: anisotropy. digital.library.unt.edu/ark:/67531/metadc4976/
Synthesis and characterization of crystalline assembly of poly Nisopropylacry-lamide)-co-acrylic acid nanoparticles.
In this study, crystalline poly(N-isopropylacrylamide-co-acrylic acid) (PNIPAm-co-AAc) nanoparticle network in organic solvents was obtained by self assembling precursor particles in acetone/epichlorohydrin mixture at room temperature followed by inter-sphere crosslinking at ~98 °C. The crystals thus formed can endure solvent exchanges or large distortions under a temporary compressing force with the reoccurrence of crystalline structures. In acetone, the crystals were stable, independent of temperature, while in water crystals could change their colors upon heating or changing pH values. By passing a focused white light beam through the crystals, different colors were displayed at different observation angles, indicating typical Bragg diffraction. Shear moduli of the gel nanoparticle crystals were measured in the linear stress-yield ranges for the same gel crystals in both acetone and water. Syntheses of particles of different sizes and the relationship between particle size and the color of the gel nanoparticle networks at a constant solid content were also presented. Temperature- and pH- sensitive crystalline PNIPAm-co-AAc hydrogel was prepared using osmosis crosslinking method. Not only the typical Bragg diffraction phenomenon was observed for the hydrogel but also apparent temperature- and pH- sensitive properties were performed. The phase behavior of PNIPAm nanoparticles dispersed in water was also investigated using a thermodynamic perturbation theory combined with lightscattering and spectrometer measurements. It was shown how the volume transition of PNIPAM particles affected the interaction potential and determined a novel phase diagram that had not been observed in conventional colloids. Because both particle size and attractive potential depended on temperature, PNIPAM aqueous dispersion exhibited phase transitions at a fixed particle number density by either increasing or decreasing temperature. The phase transition of PNIPAm-co-AAc colloids was also studied. The results from the comparison between pure PNIPAm and charged PNIPAm colloids showed that the introducing of carboxyl (-COOH) group not only contributed to the synthesis of three-dimensional nanoparticle network but also effectively increased the crystallization temperature and concentration range. The phase transitions at both low and high temperatures were observed from the turbidity change by using UV-Vis spectrometer. Centrifugal vibration method was used to make crystalline PNIPAm-co-AAc dispersion at high concentration (8%). The turbidity test proved the formation of iridescent pattern. digital.library.unt.edu/ark:/67531/metadc4671/
Synthesis and characterization of diphosphine ligand substituted osmium and ruthenium clusters.
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. digital.library.unt.edu/ark:/67531/metadc3955/
Synthesis and characterization of molecules for electron transfer research.
Dimethoxynaphthalene (donor) and quinone (acceptor) have been chosen as a suitable redox pair and are bonded to either permethylated silane chains or corresponding permethylated alkyl chains to form Acceptor-(Bridge)-Donor molecules. The idea that the s-delocalization phenomenon of silane chains may greatly facilitate ET reactions will be tested. The starting material for the donor precursor, 4-(1,4-dimethoxynaphthyl)bromocyclohexane, was 1,4-naphthoquinone. After methylation and bromination, the Grignard reagent of the resulting bromide was reacted with cyclohexanedione, mono ethylene ketal. The resulting alcohol was changed to the donor precursor through the following functional group transformation steps: dehydration, hydrogenation, deketalization and bromination. 1,4-Dibenzyloxybromobenzene, the precursor for the acceptor, was synthesized from 1,4-hydroquinone through bromination and benzylation. The connection of the two precursors and either permethylated silane chains or permethylated alkyl chains will give the final target molecules for ET research. Progress on this is included. digital.library.unt.edu/ark:/67531/metadc2683/
Synthesis and characterization of molecules to study the conformational barriers of fluorocarbon chains
Fluorocarbons are known to be stiffer than their hydrocarbon analogues, a property that underlines the extensive industrial application of fluorocarbon materials. Although there has been previous studies on the rotational barrier of molecules having fluorocarbon centers, a detailed systematic study is necessary to quantify flurocarbon stiffness. The molecules, Pyrene-(CF2)n-Pyrene, Pyrene-(CF2)n-F, Pyrene-(CH2)n-Pyrene and Pyrene-(CH2)n-H were therefore synthesized to enable the determination of the barrier to rotation of the carbon backbone in fluorocarbons. Conformational studies will be completed with steady-state and time-dependent emission spectroscopy. digital.library.unt.edu/ark:/67531/metadc2511/
Synthesis and Characterization of Platinum(II)(2-(9-anthracenylylidene)-4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione)(dichloride), Platinum(II)(2-(9-anthracenylylidene)-4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione(maleonitriledithiolate), and Platinum(II)(4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione)(4-Methyl-1,2-benzene dithiol)
Substitution of the 1,5-cyclooctadiene (cod) ligand in PtCl2(cod) (1) by the diphosphine ligand 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) yields PtCl2(bpcd) (2). Knoevenagel condensation of 2 with 9-anthracenecarboxaldehyde leads to the functionalization of the bpcd ligand and formation of the corresponding 2-(9-anthracenylidene)-4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (abpcd) substituted compound PtCl2(abpcd) (3), which is also obtained from the direct reaction of 1 with the abpcd ligand in near quantitative yield. The reaction of 3 with disodium maleonitriledithiolate (Na2mnt) affords the chelating dithiolate compound Pt(mnt)(abpcd) (4). The reaction of PtCl2(bpcd) (2) with 4-methyl-1,2-benzene dithiol under basic conditions affords Pt(tdt)(bpcd) (5). Compounds 2-5 have been fully characterized in solution by IR and NMR spectroscopies (1H and 31P), and their molecular structures established by X-ray crystallography. The electrochemical properties of 2‑5 have examined by cyclic voltammetry, and the nature of the HOMO and LUMO levels in systems 2-4 has been established by MO calculations at the extended Hückel level, the results of which are discussed with respect to electrochemical data and related diphosphine derivatives. In addition the new compounds 2-5 have been isolated by column chromatography and characterized by IR, UV-Vis spectroscopy. digital.library.unt.edu/ark:/67531/metadc12135/
Synthesis and characterization of quinoxaline-functionalized, cage-annulated oxa- and thiacrown ethers and reaction chemistry of the diphosphine ligand 2,3-bis(diphenylphosphino)-N-p-tolylmaleimide (bmi) at triosmium carbonyl clusters.
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Quinoxaline-functionalized, cage-annulated oxa- and thiacrown ethers have been synthesized as possible specific metal host systems. The synthesis and characterization of quinoxaline-functionalized, cage-annulated oxa- and thiacrown ethers have been described. The characterization of these host systems have been fully achieved in solution by using various techniques such as IR, 1H NMR, and 13C NMR spectroscopic methods, high-resolution mass spectrometry (HRMS), elemental microanalysis, and X-ray crystallographic analysis in case of one quinoxaline-functionalized, cage-annulated oxacrown ether compound. The synthesis of the diphosphine ligand 2,3-bis(diphenylphosphino)-N-p-tolylmaleimide (bmi) is described. The substitution of the MeCN ligands in the activated cluster 1,2-Os3(CO)10(MeCN)2 by the diphosphine ligand bmi proceeds rapidly at room temperature to furnish a mixture of bridging and chelating Os3(CO)10(bmi) isomers and the ortho-metalated product HOs3(CO)9[μ-(PPh2)C=C{PPh(C6H4)}C(O)N(tolyl-p)C(O)]. Thermolysis of the bridging isomer 1,2-Os3(CO)10(bmi) under mild conditions gives the chelating isomer 1,1-Os3(CO)10(bmi), whose molecular structure has been determined by X-ray crystallography. The kinetics for the ligand isomerization have been investigated by UV-vis and 1H NMR spectroscopy in toluene solution over the temperature range of 318-348 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. Orthometalation of one of the phenyl groups associated with the bmi ligand is triggered by near-UV photolysis of the chelating cluster 1,1- Os3(CO)10(bmi). digital.library.unt.edu/ark:/67531/metadc5608/
Synthesis and Characterization of Two and Three Coordinate Gold (I) Conjugated and Rigid Metallodendrimers
This dissertation is a study of two major topics that involve synthetic strategies for new classes of phosphorescent gold(I)-based metallodendrimers. The phosphorescence of organic and inorganic luminophores originates from spin-orbit coupling owing to internal or external heavy atom effects as well as metal-centered emissions. Previous work in the Omary group entailed systematically designed small molecules, metallopolymers, and unconjugated metallodendrimers that contain d10 and d8 metals, whereas this dissertation aims in part to expand such strategies to the conjugated metallodendrimer regime. In one approach novel synthetic strategies were used to make first-generation phenyl acetylene dendrimers and phosphine derivatives thereof. The phosphine dendrimers are made by tethering one of the phosphines to an unsaturated dendrimer, as such phosphine dendrimers are better chromophores and luminophores due to their structural rigidity and extended conjugation. In another approach, 2- and 3-coordinate Au(I) dendritic complexes are synthesized from these phosphine dendrimers. This study is further extended to study metallodendritic complexes with different cores, for example triphenylene-based metallodendritic complexes with six acetylene branches. The physical properties of the metallodendrimers can be modulated upon proceeding to further dendrimer generations or by using solubilizing groups on the peripheral phosphines, thus allowing better processability for thin-film fabrication as required for molecular electronic devices and higher chance for crystal growth toward accurate structural characterization. Other data produced in this project suggested that some structural alterations led to porous solids that render them suitable for realized and potential applications in energy storage and carbon capture. The interesting luminescence properties of the metallodendrimers and porous extended solids produced in this dissertation are significant toward utilizing such materials for optoelectronic applications such as energy-saving organic light-emitting diodes and optical sensors for environmental pollutants. digital.library.unt.edu/ark:/67531/metadc149678/
Synthesis and Complexation Studies of Novel Functionalized Crown Ethers and Azacrown Ethers
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Novel cage-functionalized azacrown ethers, i.e. 51, 52, 53, 55, 57, 61 and 62, which have various crown cavity and different number of nitrogen atoms incorporated, have been prepared. X-ray structures of 53, 55 and 57 have been obtained for the study of the crown topological structure. The complexation properties of crown 51, 52, 57, 61 and 62 have been evaluated via alkali metal picrate extraction, silver picrate extraction and ESI-MS study. The novel cage-fuctionalized azacrown ethers generally exhibit high avidity and selectivity towards Ag+ versus alkali metal ions and some transition metals i.e. Cu2+, Mn2+, Zn2+, Ni2+ and Pb2+. Crown 61 displays significant avidity and selectivity toward K+ in alkali metal picrate extraction experiments vis-à-vis the remaining alkali metal picrates. Three types of ditopic ion-exchange receptors for sodium hydroxide extraction study have been designed. All of the crown ether molecules have proper cavity for selective sodium complexation and have weakly acidic ionizable alcohols for sodium-proton exchange under strongly basic conditions. Crown 80 and 81 were synthesized; key intermediates for the synthesis of crown 82, 83 and 84 have been prepared. The preparation of 99 afforded an unexpected crown 103. The preparation of 109 had been attempted, but could not be successfully isolated. Four novel cage-functionalized calix[4]arene crown-5, i.e. 113-116, have been synthesized. The structures of 113 and 116 have been established by X-ray crystal structural analysis and NMR spectral analysis. The complexation properties of the four ionic receptors have been studied via alkali metal picrate extraction experiments. Crown 115 and 116 display more than modest avidity toward alkali metal ions and are most selective toward K+ vis-à-vis 113 and 114. digital.library.unt.edu/ark:/67531/metadc5593/
Synthesis and host-guest interaction of cage-annulated podands, crown ethers, cryptands, cavitands and non-cage-annulated cryptands.
Symmetrical cage-annulated podands were synthesized via highly efficient synthetic strategies. Mechanisms to account for the key reaction steps in the syntheses are proposed; the proposed mechanisms receive support from the intermediates that have been isolated and characterized. An unusual complexation-promoted elimination reaction was studied, and a mechanism is proposed to account for the course of this reaction. This unusual elimination may generalized to other rigid systems and thus may extend our understanding of the role played by the host molecules in "cation-capture, anion-activation" via complexation with guest molecules. Thus, host-guest interaction serves not only to activate the anion but also may activate the leaving groups that participate in the complexation. Complexation-promoted elimination provides a convenient method to desymmetrize the cage while avoiding protection/deprotection steps. In addition, it offers a convenient method to prepare a chiral cage spacer by introducing 10 chiral centers into the host system in a single synthetic step. Cage-annulated monocyclic hosts that contain a cage-butylenoxy spacer were synthesized. Comparison of their metal ion complexation behavior as revealed by the results of electrospray ionization mass spectrometry (ESI-MS), alkali metal picrate extraction, and pseudohydroxide extraction with those displayed by the corresponding hosts that contain cage-ethylenoxy or cage-propylenoxy spacers reveals the effect of the length of the cage spacer upon the host-guest behavior. A series of cage-annulated cryptands, cavitands and the corresponding non-cage-annulated model compounds have been synthesized. These host molecules display unusual behavior when examined by using ESI-MS techniques, i.e., they bind selectively to smaller alkali metal ions (i.e., Li+ and Na+), a result that deviates significantly from expectations based solely upon consideration of the size-fit principle. It seems likely that this behavior results from the effect of the host topology on host-guest behavior. A series of non-cage-annulated cryptands also have been synthesized. These compounds can serve as starting materials for cavitand construction. digital.library.unt.edu/ark:/67531/metadc4229/
Synthesis and Infrared Spectra of Substituted Phthalimidines
A number of N-substituted-3-hydroxy-3-phenylphthal-imidines and some of the isomeric amides have been prepared in order to study changes in the infrared spectra of these compounds due to structural changes in the molecule, particularly with reference to a hydroxyl band at 3.0µ and a carbonyl band at 5.75µ. digital.library.unt.edu/ark:/67531/metadc108144/
Synthesis and Properties of Novel Cage-Annulated Crown Ethers
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Three cage-functionalized polyoxacrown ethers (9, 10 and 12) and four novel cage-functionalized polyoxamonoazacrown ethers (18, 20, 25 and 29) that contain 3,5-disubstituted-4-oxahexacyclo[5.4.0.02,6.03,10.05,9.08,11]dodecane ("oxahexacyclic") moiety have been synthesized and their respective alkali metal picrate extraction profiles along with that of three analogues 13, 14 and 21 have been obtained. The observed avidities and selectivities of the host molecules toward complexation and transport of alkali metal picrates can be related to the size and shape of their respective macrocyclic cavity and the number of donor atoms. The effect of N-alkyl substitution on the complexation properties of azacrown ethers has been studied. The avidity of N-Et azacrown ethers toward complexation with alkali metal cations is generally higher than that of the corresponding non-N-alkylated hosts. However, the presence of an N-Et group appears to have a negligible effect upon their relative selectivities in their regards. The effect of pH on extraction process was studied; it was thereby determined that the alkali metal picrate extraction experiments are best performed at high pH (ca. 11-12). digital.library.unt.edu/ark:/67531/metadc5523/
Synthesis and properties of novel cage-functionalized crown ethers and cryptands.
A novel cryptand was synthesized which contained a 3,5-disubstituted-4- oxahexacyclo[5.4.1.02,6.03,10.05,9.08,11] dodecane "cage" moiety. In alkali metal picrate extraction experiments the cryptand exhibited high avidity towards Rb+ and Cs+, when compared with the corresponding model compound. A computational study of a series of cage-functionalized cryptands and their alkali metal-complexes was performed. The X-ray crystal structure of a K+-complexed bis-cage-annulated 20-crown-6 was obtained. The associated picrate anion was found to be intimately involved in stabilization of the host-guest complex. The interaction energy between the host-guest complex and picrate anion has been calculated, and the energy thereby obtained has been corrected for basis set superposition error. digital.library.unt.edu/ark:/67531/metadc2896/
The Synthesis and Reduction of Some N-Phenacylpyridines
This study explores the synthesis and reduction of some n-phenacylpyridines and is an investigation of various derivatives. digital.library.unt.edu/ark:/67531/metadc130232/
Synthesis and Screening of a Combinatorial Peptide Library for Ligands to Target Transferrin: Miniaturizing the Library
Combinatorial libraries are used in the search for ligands that bind to target proteins. Fmoc solid-phase peptide synthesis is routinely used to generate such libraries. Microwave-assisted peptide synthesis was employed here to decrease reaction times by 80-90%. Two One-Bead-One-Compound combinatorial libraries were synthesized on 130μm beads (one containing 750 members and the other 16, 807). The use of smaller solid supports would have many important practical advantages including; increased library diversity per unit mass, smaller quantities of library needed to generate hits, and screening could be conducted by using a standard flow cytometer. To this end, a miniaturized peptide library was synthesized on 20 μm beads to demonstrate proof of principle. A small sample from the 16,807-member library was screened against transferrin-AlexaFluro 647, a protein responsible for iron transport in vivo. A number of hits were identified and sequenced using techniques coupling nanomanipulation with nanoelectrospray mass spectrometry. digital.library.unt.edu/ark:/67531/metadc30440/
Synthesis and study of crystalline hydrogels, guided by a phase diagram.
Monodispersed nanoparticles of poly-N-isopropylacrylamide-co-allylamine (PNIPAM-co-allylamine) and PNIPAM-co-acrylic acid (AA) have been synthesized and used as building blocks for creating three-dimensional networks. The close-packed PNIPAM-co-allylamine and PNIPAM-co-AA nanoparticles were stabilized by covalently bonding neighboring particles at room temperature and at neutral pH; factors which make these networks amicable for drug loading and release. Controlled release studies have been performed on the networks using dextran markers of various molecular weights as model macromolecular drugs. Drug release was quantified under various physical conditions including a range of temperature and molecular weight. These nanoparticle networks have several advantages over the conventional bulk gels for controlling the release of biomolecules with large molecular weights. Monodispersed nanoparticles of poly-N-isopropylacrylamide-co-allylamine (PNIPAM-co-allylamine) can self-assemble into crystals with a lattice spacing on the order of the wavelength of visible light. By initiating the crystallization process near the colloidal crystal melting temperature, while subsequently bonding the PNIPAM-co-allylamine particles below the glass transition temperature, a nanostructured hydrogel has been created. The crystalline hydrogels exhibit iridescent patterns that are tunable by the change of temperature, pH value or even protein concentration. This kind of soft and wet hydrogel with periodic structures may lead to new sensors, devices, and displays operating in aqueous solutions, where most biological and biomedical systems reside. The volume-transition equilibrium and the interaction potential between neutral PINPAM particles dispersed in pure water were investigated by using static and dynamic light-scattering experiments. From the temperature-dependent size and energy parameters, the Sutherland-like potential provides a reasonable representation of the inter-particle potential for PNIPAM particles in swollen and in collapsed phases. An aqueous dispersion of PNIPAM particles can freeze at both high and low temperatures. At low temperatures, the freezing occurs at a large particle volume fraction, similar to that in a hard-sphere system; while at high temperature, the freezing occurs at low particle concentrations, driven by the strong van der Waals attraction due to the collapsed microgel particles. The calculated phase diagram has been confirmed semi-quantitatively by experiments. digital.library.unt.edu/ark:/67531/metadc4698/
The synthesis and study of poly(N-isopropylacrylamide)/poly(acrylic acid) interpenetrating polymer network nanoparticle hydrogels.
Homogeneous hydrogels made of an interpenetrating network of poly(N-isopropylacrylamide) (PNIPAm) and poly(acrylic acid) (PAAc) are synthesized by a two-step process; first making PNIPAm hydrogels and then interpenetrating acrylic acid throughout the hydrogel through polymerization. The kinetic growth of the IPN is plotted and an equation is fitted to the data. When diluted to certain concentrations in water, the hydrogels show reversible, inverse thermal gelation at about 34°C. This shows unique application to the medical field, as the transition is just below body temperature. A drug release experiment is performed using high molecular weight dyes, and a phase diagram is created through observation of the purified, concentrated gel at varying concentrations and temperatures. digital.library.unt.edu/ark:/67531/metadc5382/
The Synthesis and Testing of Differential Herbicides
This investigation was limited to the preparation of substituted phenoxyacetic acids and related compounds. The types of substances prepared for testing can, in general, be placed in three groups. These are: aryloxyacetic acids, arylmercaptoacetic acids, and those acids containing the thiophene nucleus. digital.library.unt.edu/ark:/67531/metadc75661/
Synthesis and X-ray Diffraction Structure of 8,9-Dichloropyrrolo[1,2-a]perimidin-10-one
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Treatment of dichloromaleic anhydride and 1,8-diaminonaphthalene in either benzene or toluene under refluxing conditions gives low yields of the new heterocyclic compound 8,9-dichloropyrrolo[1,2-a]perimidin-10-one. This product has been isolated and characterized in solution by NMR, IR, and UV/vis spectroscopies, and the solid-state structure of 8,9-dichloropyrrolo[1,2-a]perimidin-10-one has been established by X-ray crystallography. The nature of the HOMO and LUMO levels of 8,9-dichloropyrrolo[1,2-a]perimidin-10-one has been studied by extended Hückel molecular orbital calculations. digital.library.unt.edu/ark:/67531/metadc4268/
Synthesis and X-ray Diffraction Structures of 2-(2-thienylidene)-4,5-bis-(diphenylphosphino)-4-cyclopenten-1,3-dione and fac-BrRe(CO)3[2-(2-thienylidene)-4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione]
Treatment of 4,5 bis-(diphenylphosphino)-cyclopenten-1,3 dione with thiophene carboxyaldehyde in dichloromethane, in the presence of molecular sieves results in a new heterocyclic compound, 2-(2-thienylidene)-4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (ligand), with a high yield. This product was characterized by using both IR and NMR spectroscopic techniques and the solid-state structure of the ligand was determined using X-ray crystallography. When the ligand was treated with the solvent stabilized intermediate of ReBr(CO)5 with THF, a monomeric metal complex, fac-BrRe(CO)3[2-(2-thienylidene)-4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione] was the result. The solid-state structure of the monomeric metal complex was determined using X-ray crystallography. Photolysis and thermolysis studies of the complex will be further explored. digital.library.unt.edu/ark:/67531/metadc4942/
Synthesis, characterization, and kinetics of isomerization, C-H and P-C bond activation for unsaturated diphosphine-coordinated triosmium carbonyl clusters.
Substitution of MeCN ligands in the activated cluster Os3(CO)10(MeCN)2 by the unsaturated diphosphine ligands (Z)-Ph2PCH=CHPPh2 (cDPPEn) or 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) proceeds rapidly at room temperature to furnish the ligand-bridged cluster 1,2-Os3(CO)10(P-P) (P-P represents cDPPEn or bpcd). Heating 1,2-Os3(CO)10(P-P) leads to the formation of the thermodynamically more stable chelating isomer 1,1-Os3(CO)10(P-P). Each compound of Os3(CO)10(P-P) has been characterized by x-ray diffraction, IR, 31P NMR and 1H NMR. Ligand isomerization kinetics have been investigated by UV-VIS and 31P NMR (for cDPPEn) or 1H NMR (for bpcd) spectroscopies. The isomerization mechanism is discussed based on the activation parameters and CO inhibition (for cDPPEn) or ligand trapping experiments (for bpcd). Thermolysis of 1,1-Os3(CO)10(bpcd) in refluxing toluene gives the hydrido cluster HOs3(CO)9[μ-(PPh2)C=C{PPh(C6H4)}C(O)CH2C(O)] and the benzyne cluster HOs3(CO)8(μ3-C6H4)[μ2,η1-PPhC=C(PPh2)C(O)CH2C(O)]. Photolysis of 1,1-Os3(CO)10(bpcd) using near UV light affords HOs3(CO)9[μ-(PPh2)C=C{PPh(C6H4)}C(O)CH2C(O)] as the sole product. HOs3(CO)8(μ3-C6H4)[μ2,η1-PPhC=C(PPh2)C(O)CH2C(O)] has been characterized in solution by IR and NMR spectroscopies. Furthermore its molecular structure has been determined by X-ray crystallography. Reversible C-H bond formation in HOs3(CO)9[μ-(PPh2)C=C{PPh(C6H4)}C(O)CH2C(O)] is demonstrated by ligand trapping studies to give 1,1-Os3(CO)9L(bpcd) (where L = CO, phosphine) via the unsaturated intermediate 1,1-Os3(CO)9(bpcd). The kinetics for reductive coupling in HOs3(CO)9[γ-(PPh2)C=C{PPh(C6H4)}C(O)CH2C(O)] and DOs3(CO)9[μ-(PPh2-d10)C=C{P(Ph-d5)(C6D4)}C(O)CH2C(O)] in the presence of PPh3 give rise to a kH/kD value of 0.88, whose magnitude supports the existence of a preequilibrium involving the hydride(deuteride) cluster and a transient arene-bound Os3 species that precedes the rate-limiting formation of 1,1-Os3(CO)9(bpcd). Strong proof for the proposed hydride(deuteride)/arene preequilibrium has been obtained from photochemical studies employing the isotopically labeled cluster 1,1-Os3(CO)10(bpcd-d4ortho), whose bpcd phenyl groups each contain one ortho hydrogen and deuterium atom. Equilibrium and kinetic isotope effects in the orthometallation step has been determined by 1H NMR in photochemical studies. Kinetics for the transformation from HOs3(CO)9[μ-(PPh2)C=C{PPh(C6H4)}C(O)CH2C(O)] to HOs3(CO)8(μ3-C6H4)[μ2,η1-PPhC=C(PPh2)C(O)CH2C(O)] has been studied by UV-VIS spectroscopy for which the mechanism is discussed. digital.library.unt.edu/ark:/67531/metadc6037/
Synthesis, characterization and properties of rigid macromolecules with extended conjugation, using palladium-catalyzed alkynylated polyhaloarenes.
A synthetic approach to macromolecules of acetylenic arrays and luminescent properties is proposed and the execution of initial steps is described. Palladium-catalyzed coupling of 1,3,5-triiodobenzene with trimethylsilylbuta-1,3-diyne, trimethylsilylocta-1,3,5,7-tetrayne, and trimethylsilylhexadeca-1,3,5,7,9,11,13,15-octayne to yield the new 1,3,5-tris(trimethylsilylbuta-1,3-diynyl)benzene and the proposed 1,3,5-tris(8-(trimethylsilyl)octa-1,3,5,7-tetraynyl)benzene and 1,3,5-tris(trimethylsilyl)hexadeca-1,3,5,7,9,11,13,15-octaynyl)benzene respectively. The proposed three-coordinate Au (I) complexed macromolecules will be derived from the metallation of the aforementioned alkynylated arenes. digital.library.unt.edu/ark:/67531/metadc5206/
Synthesis of 5- (2-Thienyl) Barbituric Acid
A study of the synthesis of 5- (2-Thienyl) barbituric acid. digital.library.unt.edu/ark:/67531/metadc75442/
The Synthesis of 5-Alkyl-5-(2-Thienylmethyl)-Barbituric Acids
This thesis describes the synthesis of a series of 5-alkyl-5-(2-thienylmethyl)-barbituric acids. digital.library.unt.edu/ark:/67531/metadc75638/
The Synthesis of 5-Hetero-Substituted Dihydro-4,6(1H,5H)-Pyrimidinediones
This thesis describes the attempt to synthesize some 5-hetero-substituted dihydro-4,6(1H,5H)-pyrimidinediones as possible anticonvulsants. digital.library.unt.edu/ark:/67531/metadc108029/
Synthesis of a-(p-Aminophenylsulfonyl)-Substitutedacetophenones
This thesis describes a procedure used to synthesize a-(p-Aminophenylsulfonyl)-p-methylacetophenone, a-(p-aminophenylsulfonyl)-p-bromoacetophenone, and a-(p-aminophenylsulfonyl)-p-methoxyacetophenone for study as possible new anti-tubercular agents. digital.library.unt.edu/ark:/67531/metadc83448/
Synthesis of Antispasmodics
This thesis is a study of the synthesis of antispasmodics. digital.library.unt.edu/ark:/67531/metadc75558/
The Synthesis of Benzo(d)pyrido(a)-benzimidazole-5,12-quinone
The present investigation yielded an orange product upon refluxing 2-butyramido-3-chloro-1,4-naphthoquinone and 2-aminopyridine in ethanol. When this material was purified, by recrystallization from glacial acetic acid, the melting point was 306 [degrees]. This compound has been shown to be benzo(d)pyrido(a)-benzimidazole-5,12-quinone by the present investigation. digital.library.unt.edu/ark:/67531/metadc130422/
The Synthesis of Certain Alkyl Alpha-(2-Dialkylam Inoalkoxy)Phenylacetates
This thesis describes the procedures used in preparation of the derivatives of certain alkyl phenylacetates and the necessary intermediate compounds. Compounds resembling the structure of Benadryl were prepared in this study in the hope that at least one might prove to be of value in the fight against allergy. digital.library.unt.edu/ark:/67531/metadc75620/
Synthesis of Crown Ether/Ammonium Salt for Electron Transfer Study
The theoretical model of Beratan and Onuchic predicts a large attenuation of ET rates through hydrogen bonds; however, the effect of individual hydrogen bond on electron transfer reaction has not been systematically studied. The organic complexes in this study are a series of crown ether/ammonium salt, which incorporate a redox partner on each component of the complex. The dimethoxynaphthalene redox donor was attached to the crown ether and a series of ammonium salts was synthesized which bear substituted quinone and naphthoquinone acceptor. The complexes characterization and preliminary electron transfer rate measurement were completed with UV/Vis and steady-state emission spectroscopy. digital.library.unt.edu/ark:/67531/metadc3141/
Synthesis of cubic boron nitride thin films on silicon substrate using electron beam evaporation.
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Cubic boron nitride (cBN) synthesis has gained lot of interest during the past decade as it offers outstanding physical and chemical properties like high hardness, high wear resistance, and chemical inertness. Despite of their excellent properties, every application of cBN is hindered by high compressive stresses and poor adhesion. The cost of equipment is also high in almost all the techniques used so far. This thesis deals with the synthesis of cubic phase of boron nitride on Si (100) wafers using electron beam evaporator, a low cost equipment that is capable of depositing films with reduced stresses. Using this process, need of ion beam employed in ion beam assisted processes can be eliminated thus reducing the surface damage and enhancing the film adhesion. Four sets of samples have been deposited by varying substrate temperature and the deposition time. scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR) techniques have been used to determine the structure and composition of the films deposited. X-ray diffraction (XRD) was performed on one of the samples to determine the thickness of the film deposited for the given deposition rate. Several samples showed dendrites being formed as a stage of film formation. It was found that deposition at substrate temperature of 400oC and for a period of one hour yielded high quality cubic boron nitride films. digital.library.unt.edu/ark:/67531/metadc5542/
The Synthesis of N-Substituted Di(2-thienylmethyl)acetamides
This thesis is a study of the synthesis of N-substituted di(2-thienylmethyl)acetamides. digital.library.unt.edu/ark:/67531/metadc75702/
The Synthesis of N-(4-Nitrophenacyl)-4-Alkylpyridinium Halides and Reduction Products
The synthesis of several N-(4-nitrophenacyl)-4-alkylpyridinium halides and their reduction products, 1-(4-aminophenyl)-2-[1-(4-alkylpiperidyl)]ethanols, was undertaken because of structural analogies between these and other physiologically active compounds, such as chloroamphenicol (I), 4,4'-diaminodiphenyl sulfone (II), and 2,2-bis(p-aminophenyl)-1,1,1-trichloroethane (III). digital.library.unt.edu/ark:/67531/metadc83714/
Synthesis of some 1-Substituted-2-Methylnaphthimidazole-4,9-Diones
Imidazole derivatives of 1,4-naphthoquinones are found to have biological activity which interferes with the utilization of vitamin K or of the purines since they have groups common to these two classes of compounds. This thesis shows the preparation of some 1-substituted-naphthimidazole-4,9-diones for possible biological activity. digital.library.unt.edu/ark:/67531/metadc107971/
Synthetic Cannabinoid Usage among College Students: The Example of K2 and Spice
The primary goal of this study was to investigate the awareness and prevalence of Spice and K2 usage among a population of college students, as well as the demographics of such users. The study also sought to determine whether or not students prefer these products over natural cannabis, in addition to examining the most popular methods of obtainment and the most commonly reported side effects of K2 and Spice usage. Participants consisted of 643 undergraduate students enrolled at the University of North Texas during the fall 2011 semester. Findings indicate that while students exhibit a relatively high awareness of K2 and Spice, usage of these products is not a prevalent occurrence. Implications of the findings are discussed. digital.library.unt.edu/ark:/67531/metadc84283/