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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.
271

Φασματοσκοπία χρονικής ανάλυσης και διφωτονικής απορρόφησης οργανικών ενώσεων παράγωγων της βενζοδισθιαζόλης

Κοτσιάς, Δημήτριος 26 April 2012 (has links)
Στην παρούσα μεταπτυχιακή αυτή εργασία μελετήσαμε την συμπεριφορά για πρώτη φορά ενώσεων που είχαν σαν βάση την βενζοδισθιαζόλη. Συγκεκριμένα οι ενώσεις αυτές μελετήθηκαν με την χρήση των τεχνικών της φασματοσκοπίας διφωτονικής απορρόφησης της φασματοσκοπίας σταθερής κατάστασης και της φασματοσκοπίας φθορισμού χρονικής ανάλυσης. Αρχικά όσον αφορά την φασματοσκοπία διφωτονικής απορρόφησης, μπορέσαμε να οδηγηθούμε στα εξής συμπεράσματα: οι καλύτερες ενώσεις που παρουσιάζουν αρκετά μεγάλη διφωτονική απορρόφηση είναι τα γραμμικά μόρια (PK-439 και PK-452) σε σχέση με τα U-shaped μόρια με μέγιστη ενεργό διατομή ΔΦΑ ~2000GM. Επιπλέον παρατηρήσαμε ότι η χρήση της βενζοδισθιαζόλης σαν κεντρικός πυρήνας προκαλεί σημαντική αύξηση της διφωτονικής απορρόφησης, σε σχέση με την βενζοθιαζόλη. Τέλος, με την τεχνική της φασματοσκοπίας φθορισμού χρονικής ανάλυσης μπορέσαμε να οδηγηθούμε σε κάποιες διαπιστώσεις: συγκεκριμένα παρατηρήσαμε ότι όσο το μήκος κύματος καταγραφής μεγαλώνει, τόσο οι καμπύλες αποδιέγερσης γίνονται πιο αργές. Ακόμα διαπιστώσαμε ότι από την σύγκριση μορίων στο μήκος κύματος του μεγίστου, σε εκείνα τα μόρια που αποδιεγείρονται γρήγορα, ευνοούνται οι μη-ακτινοβολητικές διεργασίες και ταυτόχρονα παρουσιάζουν μικρή ενεργό διατομή ΔΦΑ. / --
272

Nano-antennes optiques pour l'exaltation et le contrôle de la fluorescence moléculaire dans des volumes sub-longueur d'onde

Aouani, Heykel 08 September 2011 (has links)
Les nano-antennes optiques permettent la manipulation, le confinement et l'exaltation des champs électromagnétiques dans des volumes sub-longueur d'onde. Les applications de ces nano-objetsconcernent des domaines variés tels que les nano-sources de lumière,la photovoltaïque, la microscopie, la spectroscopie... Les propriétés physiques de ces nano-antennes dépendant essentiellementde leur nature, leurs tailles et leurs géométries, lacaractérisation expérimentale de ces nano-objets est essentielle car elle permet d'en améliorer fortement le design et d'amplifier les réponses électromagnétiques.La problématique de ce travail de thèse concerne la caractérisation et l'exploitation des propriétés de nano-antennes optiques. Différentes techniques de caractérisation expérimentale de nano-antennes ont été développées au cours de cette thèse: spectroscopie de corrélation de fluorescence, suivi de dynamique temporelle de boîtes quantiques, spectroscopie sous saturation de fluorescence. Ces techniques ont été appliqués pour étudier différents types d'antennes optiques: microsphères diélectriques, nano-ouvertures simples et nano-ouvertures corruguées. Réciproquement, ces nano-antennes optiques ont été utilisées pour améliorer efficacement la détection de molécules fluorescentes en solution, avec des exaltations de fluorescence moléculaire supérieures à un facteur 100 et un contrôle de la directivité d'émission de fluorescence, ouvrant ainsi de nouvelles opportunités en biophotonique. / Optical nanoantennas allow manipulation, confinement and enhancement of light in sub-wavelength volumes. The applications of these nano-objects are related to various fields such as nano-lightsources, photovoltaic, microscopy, spectroscopy... The physical properties of these nanoantennas depending mainly on their nature,sizes and geometries, the experimental characterization of thesenano-objects is essential because it allows to improve significantly their design and amplify the electromagnetic responses.The focus of this work concerns the characterization and exploitationproperties of optical nanoantennas. Several experimental characterization techniques of nanoantennas have been developedduring this thesis: fluorescence correlation spectroscopy FCS,temporal dynamics monitoring of quantum dots, spectroscopy bysaturated excitation of fluorescence. These techniques were appliedto study different types of optical antennas: dielectricmicrospheres, bare nanoapertures and corrugated nanoapertures. Theseoptical antennas have been used to effectively improve the detectionof fluorescent molecules in solution, with fluorescence enhancementgreater than a factor of 100, together with a directivity control ofthe fluorescence emission, opening new opportunities inbiophotonics.
273

Phase Sensitive Estimation Of Fluorescence Lifetime For Fiber Optic Biosensors

Vadde, Venkatesh 06 1900 (has links)
Fluorescence lifetime determination and allied studies find application in spectroscopy in general and fiber optic biosensors in particular. Instruments and sensors cited in literature however use open loop, intensity based techniques with sophisticated detectors and components. We propose phase sensitive signal processing schemes to estimate the fluorescence lifetime using simple detectors and components, without compromising on accuracy. The performance of the schemes proposed is analysed and contrasted from a communications (signals and systems) point of view. The resolution and sensitivity limits imposed in processing the signal, by systematic errors and additive noise, are derived for the schemes suggested. It is found that systematic errors impose a phase resolution limit of about 2°. We then study the suitability of different detectors and channels for application in phase sensitive fluorescence biosensors we analyse the effect of systematic limitations as well as additive noise, in the detection/transmission process, from the point of view of the components used. Certain fundamental limits of operation in terms of excitation intensities are derived for different detector-channel combinations, with a view to obtain a given resolution. A photodiode used with a fiber bundle is found to be sufficient for accurate phase read outs with 10"4 radians resolution. A PMT used in conjunction with a multimode fiber serves as a very good device for microsensing applications Lastly, the biosensor for oxygen sensing, the ruthenium complex, is studied for standardisation of the sensor. We examine the quenching of fluorescence, the repeatability and reusability of the sensor, the stability of the instrument and such.
274

OPTICAL MEASUREMENT OF ENVIRONMENTAL URANIUM USING POROUS SILICA MATERIALS

Chen, Chien-Cheng 17 June 2010 (has links)
The focus of this research is on the optical measurement of uranyl in a solid matrix using fluorescence spectroscopy. Nanoporous silica-based materials were used to extract uranyl from contaminated soil and to enhance the fluorescence intensity and lifetime. The fluorescence lifetime and intensity of uranyl ions adsorbed on porous silica-based materials of varying pore size was measured as a function of pH and in the presence of fluoride. The feasibility of uranyl fluorescence detection on the top of soil by silica gel is carried out by four types of natural soil. The results show that the uranyl fluorescence intensity can be enhanced by approximately two orders of magnitude by the silica nanoporous matrix from pH 4-12 with the greatest enhancement occurring from pH 4-7. The enhanced fluorescence lifetime can be used in time-gated measurements to help minimize the influence of background environmental fluorophores. The pH and the fluoride variation causes different uranyl speciation and results in a peak shift in the fluorescence spectrum. The mechanism of the uranyl ion on the silica nanoporous matrix was studied through 15 different silica materials with different water content ratios and various concentrations of uranium on different silica structures. The result shows that the particle size, pore size, water content and uranyl concentration on silica surfaces are all important factors for optimizing the fluorescence intensity. The spacing between silica materials, either the pore inside materials or the space between particles, causes the variety of uranyl distribution on the material surface and changes the fluorescence performance. Also, X-Ray Photoelectron Spectroscopy (XPS) is used to identify the possible uranyl surface species on silica. The fluorescence emission spectra from silica materials and the XPS results are consistent with the presence of two different uranyl compounds. The specific surface area of silica materials plays an important role on uranyl adsorption mechanism. To further enhance the sensitivity, an optical ball lens was used to preferentially direct the fluorescence signal toward the excitation source in standoff measurements. The application of the ball lens was found to increase the detection distance up to 14 times.
275

Espectroscopia da fluorescência na citricultura / Fluorescence spectroscopy in citrus

Lins, Emery Cleyton Cabral Correia 06 October 2009 (has links)
O cancro cítrico é uma das doenças mais temidas da citricultura devido ao seu poder de proli-feração nas fazendas, aos danos causados às plantas e aos frutos e à forma de combate adota-da pelos órgãos responsáveis através da erradicação das plantas contaminadas e de outras em sua vizinhança. No Brasil, um dos principais motivos que minimiza a eficiência da erradicação do cancro cítrico é a confirmação do diagnóstico, que necessita ser realizada em alguns laboratórios credenciados. A análise de muitas amostras em conjunto com o tempo gasto com o transporte aumenta a chance de proliferação da doença no campo. Neste trabalho aplicamos técnicas de espectroscopia da fluorescência em folhas de culturas cítricas na intenção de pro-por um método de diagnóstico do cancro cítrico a ser realizado na fazenda e com resposta em tempo real. As amostras experimentais são folhas de variedades cítricas sadias e contaminadas com cancro ou outras doenças. Iniciamos o trabalho aplicando espectroscopia da fluorescência no laboratório. Os resultados provaram a viabilidade do método, mas revelou uma enorme sobreposição de dados ao tentar discriminar o cancro de outra doença. Análises com-plementares nos revelaram que os experimentos deveriam ser feitos no campo, identificando plantas contaminadas e tomando a fluorescência de folhas sadias como referência. A espec-troscopia da fluorescência no campo foi feita com um espectrômetro portátil. O resultado nos possibilitou propor critérios de discriminação do cancro baseado em figuras de mérito. O melhor critério apresentou 79% de acertos, com 88% de sensibilidade e 68% de especificidade. Concluímos que os valores poderiam ser melhores se a espectroscopia fosse realizada com imagens, pois as variações do espectro ocorrem devido ao posicionamento da fibra na lesão do cancro. Passamos a estudar a espectroscopia das imagens da fluorescência com um sistema baseado em um espectrógrafo. Os resultados provaram a viabilidade do estudo e revelaram particularidades espaciais e espectrais das doenças. Infelizmente essa instrumentação só pode ser usada no laboratório, por isso optamos por desenvolver outro sistema mais simples e robusto, a base de uma roda de filtros com filtros passa-banda. Os re-sultados revelaram novas particularidades espaciais e espectrais das amostras, porém nos revelou a necessidade de um processamento de imagem para obter análises quantitativas. O sistema de imagens com filtro ainda foi usado em outro experimento complementar onde as imagens forneceram resultados quantitativos, provando a funcionalidade da técnica. / Citrus canker is one of the most feared diseases of citrus due to its dissemination in the farms, the damage caused to plants and fruits and how to combat adopted by national government through the eradication of infected plants and others in your neighborhood. In Brazil, one of the main reasons that minimizes the effectiveness of citrus canker`s eradication is the confir-mation of the diagnosis by specialized laboratories. The time spent to transport and to analyses many samples increases the chance of canker spreading in the field. In our work we apply spectroscopic techniques of fluorescence in leaves of citrus crops with the aim to propose a method for diagnosis of citrus canker to be held on the farm and real-time response. The expe-rimental samples are leaves of healthy citrus varieties and contaminated with canker or other diseases. We began the work by applying fluorescence spectroscopy in the laboratory. The results proved the feasibility of the method, but showed a huge overlap of data to try to dis-criminate cancer from other diseases. Further analysis revealed that those experiments should be done in the field, focusing to identify infected plants and taking the fluorescence of healthy leaves as a reference. Fluorescence spectroscopy in the field was made with a portable spectrometer. The result allowed us to propose some criteria for canker discrimination based on figures of merit. The best criteria presents 79% correct tests, with 88% sensitivity and 68% specificity. We conclude that these values could be better if the spectroscopy was performed with images, because the variations of the spectrum are due to the positioning of the fiber over the canker lesion. We study the spectroscopy of fluorescence images with a system based on a spectrograph. The results proved its feasibility and revealed spatial and spectral particular features of the diseases. Unfortunately, this instrumentation can only be used in the laborato-ry, so we decided to develop another system more simple and robust. The new system is based on a filter wheel with band-pass filters. The results revealed new spatial and spectral characteristics of the samples, but revealed the need for an image processing for quantitative analysis. This imaging system was still used in another supplementary experiment where the images have provided quantitative results, proving the functionality of the technique.
276

Espectroscopia da fluorescência na citricultura / Fluorescence spectroscopy in citrus

Emery Cleyton Cabral Correia Lins 06 October 2009 (has links)
O cancro cítrico é uma das doenças mais temidas da citricultura devido ao seu poder de proli-feração nas fazendas, aos danos causados às plantas e aos frutos e à forma de combate adota-da pelos órgãos responsáveis através da erradicação das plantas contaminadas e de outras em sua vizinhança. No Brasil, um dos principais motivos que minimiza a eficiência da erradicação do cancro cítrico é a confirmação do diagnóstico, que necessita ser realizada em alguns laboratórios credenciados. A análise de muitas amostras em conjunto com o tempo gasto com o transporte aumenta a chance de proliferação da doença no campo. Neste trabalho aplicamos técnicas de espectroscopia da fluorescência em folhas de culturas cítricas na intenção de pro-por um método de diagnóstico do cancro cítrico a ser realizado na fazenda e com resposta em tempo real. As amostras experimentais são folhas de variedades cítricas sadias e contaminadas com cancro ou outras doenças. Iniciamos o trabalho aplicando espectroscopia da fluorescência no laboratório. Os resultados provaram a viabilidade do método, mas revelou uma enorme sobreposição de dados ao tentar discriminar o cancro de outra doença. Análises com-plementares nos revelaram que os experimentos deveriam ser feitos no campo, identificando plantas contaminadas e tomando a fluorescência de folhas sadias como referência. A espec-troscopia da fluorescência no campo foi feita com um espectrômetro portátil. O resultado nos possibilitou propor critérios de discriminação do cancro baseado em figuras de mérito. O melhor critério apresentou 79% de acertos, com 88% de sensibilidade e 68% de especificidade. Concluímos que os valores poderiam ser melhores se a espectroscopia fosse realizada com imagens, pois as variações do espectro ocorrem devido ao posicionamento da fibra na lesão do cancro. Passamos a estudar a espectroscopia das imagens da fluorescência com um sistema baseado em um espectrógrafo. Os resultados provaram a viabilidade do estudo e revelaram particularidades espaciais e espectrais das doenças. Infelizmente essa instrumentação só pode ser usada no laboratório, por isso optamos por desenvolver outro sistema mais simples e robusto, a base de uma roda de filtros com filtros passa-banda. Os re-sultados revelaram novas particularidades espaciais e espectrais das amostras, porém nos revelou a necessidade de um processamento de imagem para obter análises quantitativas. O sistema de imagens com filtro ainda foi usado em outro experimento complementar onde as imagens forneceram resultados quantitativos, provando a funcionalidade da técnica. / Citrus canker is one of the most feared diseases of citrus due to its dissemination in the farms, the damage caused to plants and fruits and how to combat adopted by national government through the eradication of infected plants and others in your neighborhood. In Brazil, one of the main reasons that minimizes the effectiveness of citrus canker`s eradication is the confir-mation of the diagnosis by specialized laboratories. The time spent to transport and to analyses many samples increases the chance of canker spreading in the field. In our work we apply spectroscopic techniques of fluorescence in leaves of citrus crops with the aim to propose a method for diagnosis of citrus canker to be held on the farm and real-time response. The expe-rimental samples are leaves of healthy citrus varieties and contaminated with canker or other diseases. We began the work by applying fluorescence spectroscopy in the laboratory. The results proved the feasibility of the method, but showed a huge overlap of data to try to dis-criminate cancer from other diseases. Further analysis revealed that those experiments should be done in the field, focusing to identify infected plants and taking the fluorescence of healthy leaves as a reference. Fluorescence spectroscopy in the field was made with a portable spectrometer. The result allowed us to propose some criteria for canker discrimination based on figures of merit. The best criteria presents 79% correct tests, with 88% sensitivity and 68% specificity. We conclude that these values could be better if the spectroscopy was performed with images, because the variations of the spectrum are due to the positioning of the fiber over the canker lesion. We study the spectroscopy of fluorescence images with a system based on a spectrograph. The results proved its feasibility and revealed spatial and spectral particular features of the diseases. Unfortunately, this instrumentation can only be used in the laborato-ry, so we decided to develop another system more simple and robust. The new system is based on a filter wheel with band-pass filters. The results revealed new spatial and spectral characteristics of the samples, but revealed the need for an image processing for quantitative analysis. This imaging system was still used in another supplementary experiment where the images have provided quantitative results, proving the functionality of the technique.
277

Molekulare Orientierung als Kontrastmechanismus in der Fluoreszenzmikroskopie und konfokale Multidetektor-Scanning-Mikroskopie / Molecular Orientation as Contrast Mechanism for Fluorescence Microcopy and Confocal Multidetector-Scanning-Microscopy

Grunwald, Matthias 24 September 2015 (has links)
Die vorliegende Arbeit befasst sich mit zwei neuen methodischen Ansätzen auf dem Gebiet der Fluoreszenzmikroskopie. Im ersten Teil der Arbeit wir eine Methode vorgestellt, mit der die Winkelselektivität der Fluoreszenzanregung verbessert werden kann. Die ExPAN (excitation polarization angle narrowing) genannte Technik nutzt stimulierte Emission, um den Effekt der Photoselektion zu vergrößern. ExPAN lässt sich potentiell für verschiedene Methoden einsetzen, in denen fluoreszenzmarkierte Proben untersucht werden und ist insbesondere im Kontext von Fluoreszenzanisotropie-Messungen oder der Bestimmung von molekularen Orientierungen von Interesse. Solche Methoden finden in den Biowissenschaften breite Anwendung und werden z.B. zum Studium von Rezeptor-Liganden-Interaktionen oder der Proteindynamik eingesetzt. Im Rahmen der Arbeit wird ExPAN in Kombination mit einem neuen Ansatz in der Weitfeldmikroskopie untersucht, bei der die Orientierung von Farbstoffmolekülen als Kontrastmechanismus genutzt wird. Dabei wird die Polarisationsrichtung des Anregungslichts rotiert, um Informationen über die molekulare Orientierung zu gewinnen. Aufgrund der Photoselektion weist das Fluoreszenzsignal von Molekülen mit bevorzugter Ausrichtung dadurch eine periodische Modulation auf. Es wird gezeigt, dass diese Information zur Unterscheidung von Molekülen mit abweichender Orientierung genutzt werden kann, selbst wenn sich deren Signale räumlich überlagern. Für die Versuche wurde ein modifiziertes Weitfeld-Mikroskop konstruiert und die Methode zum einen experimentell an Einzelmolekülen und zum anderen mittels Simulationen erprobt. Dabei konnten Signale von Farbstoffmolekülen mit einem Abstand von bis zu 80 nm separiert werden. Darüber hinaus wurde ein moduliertes Fluoreszenzsignal bei oberflächenmarkierten Mikropartikeln in wässriger Lösung sowie bei fixierten biologischen Proben beobachtet. Eine Verbesserung der Photoselektion durch ExPAN wird experimentell nachgewiesen und gezeigt, dass mit ExPAN auch ähnlich orientierte Moleküle unterschieden werden können. Im zweiten Teil der Arbeit wird eine Methode zur Verbesserung der Auflösung von konfokalen Laser-Scanning-Mikroskopen vorgestellt, die als Multidetektor-Scanning (MDS) bezeichnet wird und auf dem Prinzip der Image-Scanning-Mikroskopie (ISM) beruht. Mit ISM lässt sich die Auflösung von Fluoreszenzmikroskopen theoretisch verdoppeln. Da ISM einen Flächendetektor voraussetzt, wurden in der Vergangenheit hauptsächlich CCD oder CMOS Kameras als Detektoren eingesetzt. In dieser Arbeit werden anstelle einer Kamera mehrere Einzelphotonendetektoren verwendet und über ein Glasfaserbündel zu einem Flächendetektor kombiniert. Dadurch ist es erstmals möglich, die Methode in Verbindung mit Fluoreszenzlebensdauer-Mikroskopie (FLIM) einzusetzen. FLIM hat sich in den Biowissenschaften als wichtige Mikroskopie-Technik etabliert und wird unter anderem bei Protein-Protein-Interaktionsstudien oder zur Untersuchung des NADH-Metabolismus eingesetzt. Die Verbesserung der räumlichen Auflösung von FLIM mit MDS ist somit für eine Reihe von biologischen Fragestellungen von potentiellem Interesse. Im Rahmen der Arbeit wurde ein Multidetektor-Scanning-Mikroskop konstruiert und durch die Vermessung von fluoreszierenden Mikropartikeln charakterisiert. Eine Verbesserung der Auflösung durch MDS wird an fixierten biologischen Proben demonstriert. Dabei wurde eine Auflösung von 168 nm mit MDS sowie 146 nm mit MDS und Dekonvolution erreicht. Schließlich wird die Kombination der Methode mit Fluoreszenzlebensdauer-Mikroskopie demonstriert.
278

Měření vnitrobuněčné koncentrace iontů v mikroorganismech / The monitoring of intracellular ion concentrations in microbial cells

Vodáková, Adéla January 2013 (has links)
The Master Thesis focuses on monitoring of intracellular ion concentrations in bacteria Escherichia coli and yeast Saccharomyces cerevisiae using genetically encoded fluorescent probes with green fluorescent protein (GFP). Aquired knowledge about this protein and its spectral characteristics is summarized in the introduction. For experimental study a pH-sensitive sensor which displays a ratio change of two excitation fluorescence peaks - pHluorin - was chosen. This probe was tested in bacteria and yeast cells. The experiments concentrated on the ability of the cell to maintain a constant cytosolic pH under various conditions like different pH values of the suspension, addition of glucose or KCl to the suspension. Another topic discussed in the thesis is the elimination of the cell autofluorescence from the GFP signal. For this purpose the synchronous fluorescence scan technique was succesfully used. I have found out that by using this method the measurements of cytosolic pH values are even more accurate thanks to the improved signal to noise ratio.
279

Studies of molecular motions by fluorescence microscopy at single molecule and single fiber levels

Lange, Jeffrey J. January 1900 (has links)
Doctor of Philosophy / Department of Chemistry / Daniel A. Higgins / In this dissertation, state-of-the-art fluorescence microscopy techniques are employed to probe unique nanoscale phenomena in poly(dimethylsiloxane) (PDMS) films and on single carbon nanofibers. In one study, the mobility and physical entrapment of single dye molecules in dry and solvent-loaded PDMS films is explored. Experiments are performed under dry nitrogen and at various levels of isopropyl alcohol (IPA) loading from the vapor phase, as monitored by a PDMS-coated quartz-crystal microbalance. Single molecules are shown to be predominantly immobile under dry conditions and mostly mobile under IPA-saturated conditions. FCS is used to measure the apparent diffusion coefficient, yielding a mean that is virtually independent of IPA loading and sample class. An increase in the population of mobile molecules under high IPA conditions is attributed to the filling of film micropores with solvent, rather than by incorporation of molecularly dispersed solvent into the PDMS. In a second study, the molecular mobility of both neutral and cationic molecules in cured PDMS films is studied as a function of oligomer extraction. Cross correlation and Bayesian burst analysis methods were used to quantify the populations of fixed and total molecules, respectively. The results show that the total concentration of dye increases with increased oligomer extraction, while the relative populations of fixed and mobile molecules decrease and increase, respectively. These results are relevant to the use of PDMS in microfluidics, nanofiltration and pervaporation membranes and solid phase microextraction fibers. In a final study, molecular beacons (MBs) were immobilized onto the ends of single, sol-gel encapsulated vertically-alligned carbon nanofibers (VACNFs) attached to a silicon electrode. MB fluorescence was monitored as a function of the potential applied to the VACNF in a three-electrode electrochemical cell. Application of positive potentials attracts the negatively charged backbone of the MB, causing hybridization of the stem and a reduction in beacon fluorescence. Negative potentials cause dehybridization of the stem, and an increase in MB fluorescence. This study presents the first measurement of potential-dependent dehybridization/rehybridization of MBs attached directly to the end of a single VACNF. These studies will help to characterize the mechanism by which future lab-on-a-chip devices will detect harmful bio-organisms.
280

Synthesis, spectroscopic properties and cytotoxicity of boron- dipyrromethene fluorescent dyes

Bipath, Nirvashini 14 January 2015 (has links)
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.

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