No description available.

Submitted in fulfilment of the requirements of the Degree of Master of Technology: Chemistry, Durban University of Technology. 2014. / In this study, we report the synthesis of three quinolone bearing imidazole derivatives 2, 3 and 4 and two quinolone bearing BODIPY dyes 5 and 7. In the synthesis of 2, 3 and 4, the first step was the preparation of the starting compound 2-chloro-3-formyl quinoline (1); the Vilsmeier-Haack cyclisation protocol was used. Compound 1 was used with the appropriate diamine, together with POCl3 to produce 2, 3 and 4. These compounds were characterized by IR, 1H-NMR and 13C-NMR. In the synthesis of 5, compound 1 was used whilst 6 was used for the synthesis of 7. This was via. a one-pot synthesis using conventional reflux apparatus and Schlenk technique. These compounds were characterized by IR, 1H-NMR and 13C-NMR. Four other BODIPY dyes were also synthesized but their purification by column chromatography were unsuccessful. However a HPLC method was developed using 2 as a model; the best eluting solvent was 65 % methanol. After synthesis, 2, 3, 4, 5 and 7 were used for spectroscopic studies by UV-visible and fluorescence spectroscopy. In the UV-visible studies, 2, 3 and 4 were dissolved, separately, in five solvent viz. ethanol, methanol, dichloromethane, chloroform and acetonitrile. The UV profile of each compound was obtained and the maximum absorbance was then used for fluorescence studies. In the fluorescence studies, all the compounds displayed a fluorescence nature when excited with the various wavelengths. The fluorescence properties, namely Stoke shift, quantum yield, life time, molar absorptivity and brightness, were investigated to establish the properties of each compound in all five solvent systems. The Stoke shift was evident in all compounds and the quantum yields were below one which indicates no other electron transfer mechanisms occurring. The results displayed a favorable response and this further lead to analysis of the synthesized compounds for it potential application as a chemosensor. Eight metal ions were used to investigate this property. All eight metal ions, when reacted with the synthesized compounds, as ligands, showed chemosensor properties, viz. photon induced electron transfer, inter-molecular charge transfer and fluorescence resonance electron transfer, as a quenching and enhancement of emission and excitation peaks were observed. The compounds were further investigated for its potential for its use as a photovoltaic cells. The energies of the compounds were obtained from the analyses of the reflectance and transmission spectra. It was found that the synthesized compounds displayed properties which were positive for its use as a photovoltaic cell. Biological analyses using molecular docking analyses and MTT assays were conducted to determine the use of these as an anti-cancer drug. Compounds 2 and 3 formed hydrogen bonds with GLU 25 and LEU 27, respectively with MDM2-p53 proteins. Following the molecular docking studies, the MTT assay was performed on all five synthesized compounds. The BODIPYs with the quinoline moieties demonstrated a reduction in the rate of A549 cell proliferation when compared to the imidazole and benzimidazoles; this was observed for compounds 5 and 7. Further, a comparison between imidazoles clearly shows that compounds 3 and 4 also decreased cell proliferation. In contrast compound 2 exhibited an increased rate of cell proliferation. The optical density of the control cell, is much higher that the plates for concentration 31.25 µg/ mL to 500 µg/ mL. However 2 cannot be discarded; this compound clearly shows that it possesses anti-hyperglycaemic properties and further studies are recommended.

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Impact polypropylene copolymers (IPC) are commercially used in a variety of applications. They are very complex materials and extensive studies have been conducted to understand the relationship between their chemical structure, morphology and impact properties. The distribution of ethylene propylene rubber (EPR) within IPC has drawn much attention but visualization of the morphology is difficult. In this study a fluorescent marker was used to probe the distribution of EPR within the crystalline and semi-crystalline fraction. The EPR was removed from a commercial IPC and labelled with a fluorescent marker. In this study a method utilizing the hydrophilic nature of cellulose nanowhiskers (CNW) was developed to label the EPR. CNW were labelled with fluorescein-5’-isothiocyanate (FITC) and rhodamine B (RhB) using a one-step procedure. The labelled CNW were incorporated into the EPR by means of sonication. The mobility of the labelled CNW within the EPR film was investigated by confocal fluorescence microscopy (CFM), and showed that the labelled whiskers did not move within the EPR, thus substantiating the validity of this approach. The labelled EPR was recombined with the crystalline fraction by means of injection moulding and was analysed by CFM, and the distribution of the labelled EPR was evaluated. Confocal fluorescence microscopy showed an even distribution of the labelled rubber throughout the injection moulded sample. The miscibility of two EPRs within the IPC matrix in the melt was also investigated using this technique. CFM showed that the technique has promise to prove miscibility or the lack thereof when chemically similar materials are combined in the presence of morphologically different matrix materials. / AFRIKAANSE OPSOMMING: Impak polipropileen kopolimere (IPK) word kommersieel gebruik in ‘n wye reeks produkte. Die samestelling van hierdie kopolimere is baie ingewikkeld en uitgebreide studies is al gedoen om hul chemiese samestelling op molekulêre vlak te verstaan. Baie studies met betrekking tot die verspreiding van die etileen-propileen rubber (EPR) binne in hierdie impak polipropileen kopolimere is al gedoen, maar visualisering van die morfologie is moeilik en beperk. Hierdie kennis kan bydra tot die verbetering van hul chemiese eienskappe en toepassings. In hierdie studie word ʼn fluorosserende merker gebruik om die verspreiding van die EPR binne die kristallyne en semikristallyne fraksie te ondersoek. Die EPR is verwyder vanuit 'n kommersiële IPK en is gemerk met 'n fluoresserende merker. In hierdie studie is 'n metode ontwikkel om die EPR te merk deur gebruik te maak van die hidrofiliese eienskap van sellulose nanovesels (SNV). Die SNV is gemerk met fluoressien-5'-isotiosianaat (FITC) en rhodamien B (RhB) met behulp van 'n eenstap proses. Die gemerkte SNV is deur middel van sonikasie in die EPR versprei. Die mobiliteit van die gemerkte SNV binne-in die EPR film is ondersoek deur gefokusde fluoressensie mikroskopie (GFM) en het getoon dat die gemerkte vesels nie binne die EPR beweeg nie. Dit bevestig dus die geldigheid van hierdie benadering. Die gemerkte EPR is herkombineer met die kristallyne fraksie deur middel van spuitgiet en is geanaliseer deur GFM en die verspreiding van die gemerkte EPR is geëvalueer. GFM het 'n eweredige verspreiding van die gemerkte rubber regdeur die moster wat gespuitgiet is getoon. Die mengbaarheid van twee EPRs binne-in die IPK matriks is ook ondersoek deur gebruik te maak van hierdie tegniek. GFM het getoon dat hierdie tegniek waarde inhou om te bewys dat twee produkte mengbaar is of nie, al word hulle geherkombineer word met ‘n matriks wat morfologiese van hul verskil.

The research described in this dissertation is the first evaluation and application of a new class of optical detectors, two-dimensional charge-coupled device (CCD), for low-light level chemiluminescence and other luminescence spectroscopies. This research conclusively demonstrates the superior qualitative and quantitative performance of spectrometric systems which employ these detectors. It is experimentally shown that a single detector element of a CCD has comparable or superior sensitivity to the most sensitive single channel detectors; photomultiplier tubes (PMT). The results from the application of the CCD detector system to molecular spectroscopies (fluorescence, chemiluminescence, fluorescence detection of high performance liquid chromatography (HPLC) effluents, and chemiluminescence detection of HPLC effluents) and atomic spectroscopies (spatially and spectrally resolved spark and direct current plasma are presented). The results of operating the CCD in specialized readout modes developed in this research termed charge dependent variable binning (CDVB), simultaneous variable binning (SVB), and continuous high speed spectral framing (CHSF) are described and applied. The CDVB and SVB techniques allow very sensitive quantitation of spectrally resolved and unresolved signals with very wide dynamic ranges without prior knowledge of the signal intensity. Finally, CHSF technique provides spectrally resolved temporal study of extended period luminescence emission with millisecond time resolution. The results of unique algorithms to restore the integrity of the image obtained with a two-dimensional CCD detector are described and applied. The algorithms implemented are for removing variations in detector sensitivity and responsivity and spectrometer efficiency, as well as providing digital image filtering.

No description available.

No description available.

M.Sc., Faculty of Science, University of the Witwatersrand, 2011 / The objective of the study was to investigate the preparation of glass beads for base metal analysis of mining samples prior to x-ray fluorescence analysis. The research method used included the investigation of different fluxes, oxidising, non-wetting agents, fusion temperature and time. The experiments were carried out using different fusion instruments: Electrofluxer and Katanax followed by both EDXRF and WDXRF analysis. The x-ray spectrometers were calibrated with standards prepared from pure oxides and the results compared to values determined by alternative techniques. Different statistical methods were used to validate the experiments including factorial designs. Not all the elements and oxides were recovered successfully, however, perfect glass beads were prepared. The two areas of concern were addressed successfully: firstly the loss of copper was overcome by using an alternative heating mechanism of the Katanax and sodium iodide as the non-wetting agent. Secondly, the sulphur was successfully oxidised and retained in the glass beads.

by Siu-kai Tse. / Bibliography: leaves 100-103 / Thesis (M.Ph.)--Chinese University of Hong Kong, 1984

Thesis (M.S.)--State University of New York at Binghamton, Department of Chemistry, 2006. / Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references. Available also from UMI/Dissertation Abstracts International.