Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 68-77). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 68-77). Also available on the Internet.

Carbon-carbon bond forming reactions are vital to the synthesis of natural products and pharmaceuticals. In 2003, the 200 best selling prescription drugs reported in Med Ad News are all organic compounds. Synthesizing these compounds involves many carbon-carbon bond forming processes, which are not trivial and typically generate large amounts of waste byproducts. Thus, development of an atom economical and environmentally benign carbon-carbon bond forming methodology is highly desirable. Hydrogenation is one of the most powerful catalytic reactions and has been utilized extensively in industry. Although carbon-carbon bond forming reactions under hydrogenation conditions, such as, alkene hydroformylation and the Fischer-Tropsch reaction are known, they are limited to the coupling of unsaturated hydrocarbons to carbon monoxide. Recently, a breakthrough was made by the Krische group, who demonstrated that catalytic hydrogenative C-C bond forming reactions can be extended to the coupling partners other than carbon monoxide. This discovery has led to the development of a new class of carbon-carbon bond forming reactions. Herein, an overview of transition metal-catalyzed reductive couplings of [pi]-unsaturated systems employing various external reductants is summarized in Chapter 1. Chapters 2-4 describe a series of rhodium- and iridium-catalyzed asymmetric hydrogenative couplings of various alkynes to a wide range of imines and carbonyl compounds. These byproduct-free transformations provide a variety of optically enriched allylic amines and allylic alcohols, which are found in numerous natural products, and are used as versatile precursors for the synthesis of many biologically active compounds. Transfer hydrogenation represents another important class of reactions in organic chemistry. This process employs hydrogen sources other than gaseous dihydrogen, such as isopropanol. The Krische group succeeded in developing a new family of transfer hydrogenative carbon-carbon bond formation reactions. Chapter 5 presents two novel ruthenium- and iridium-catalyzed transfer hydrogenative carbonyl allylation reactions. The catalytic system employing iridium complexes enables highly enantioselective carbonyl allylation from both the alcohol and aldehyde oxidation level. These systems define a departure from the use of preformed organometallic reagents in carbonyl additions that transcends the boundaries of oxidation level. / text

The problematics of the teaching and learning of chemical bonding has been widely reported in the literature. Following this, Taber (2001) proposed a teaching sequence alternative to those available in existing curriculum documents and textbooks. He proposed that teaching be started from metallic structure to ionic structure, then giant covalent structure and finally simple molecular structure. During teaching, teachers should be cautioned about the use of language, the undue emphasis on the role of atoms (atomic ontology), the explication of the nature of bonding (based on electrostatic forces rather than electron transfer or sharing), and a better integration of the relationship between bonding and structure. In relation to the literature about scientific modelling, bonding should be taught as an ‘explanation’ of properties of chemicals, rather than a mere ‘description’ of structure. This paper reports an empirical study of a class of Year 10 students’ learning outcomes based on the proposed teaching sequence and emphases. Throughout the learning of the topic ‘chemical bonding’ which spanned two months, three students ranged from the highest to medium achieving students in the class were selected for interviews. Each student was interviewed on four separate occasions in the course of their learning of ‘chemical bonding’. Their understanding of concepts in relation to chemical bonding was probed through their verbal and visual representations. The effectiveness of the teaching sequence was evaluated in the light the alternative conceptions reported in the literature, strategy and suggestions for further improvements were discussed. / published_or_final_version / Education / Master / Master of Education

No description available.

No description available.

The Knoevenagel reaction was applied to form a carbon-carbon double bond between the aldehydes (HMF, furfual) and an alpha di-carbonyl compound. The alpha di-carbonyl compound used was malonic acid, which can be bio-derived from glucose along fermentation routes. The effects of solvents (THF, water, ethanol, isopropanol, ethyl ether, toluene) and catalysts (e.g. homogeneous and heterogeneous amines, solid basic oxides) on the yields of alpha-beta unsaturated acids were investigated. It was found that the homogeneous amines worked well in THF solvent (90-100% conversion, 99% selectivity for furfural and HMF), while the poly(styrene) supported ethylenediamine gave a higher conversion and selectivity for HMF (65± 5%, 99% selectivity) over furfural (58 ± 7%, 99% selectivity). This trend was also present in competition reactions where both HMF and furfural were reacted in the same vessel. á-â Unsaturated mono-acids for both HMF and furfural were identified as minor side products. However, levulinic acid did not work as well under the conditions studied. Lastly, among the solvents studied, several caused precipitation of the Knoevenagel products.

"Work carried out by the author between March 1953 and January 1957 as a member of the Biophysics Group of the Physics Department of the University of Adelaide."--Pref. / "December 1957." / Includes bibliographical references (leaves 131-135) / vii, 135 leaves : ill. ; 26 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physics, 1957

"February 1955." / Includes bibliographical references (leaves 118-122) / 122 leaves : ill. ; 26 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Object of this project has been the establishment of a crystallographic laboratory sufficiently complete to enable a crystal structure analysis to proceed from the initial inspection of the crystal to the final presentation of electron density data in a two dimensional projection form. Parabanic acid was selected for the first analysis. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physics, 1955

Thesis (Ph. D.)--University of Hong Kong, 2007. / Also available online.