The opening section describes the development of the instrument from an existing Raman spectrometer operating in the visible region with Ar-ion laser excitation. In the first part of this section the steps carried out to improve the performance of the visible Raman system are outlined. In the second part, the development of the near-IR Raman system is described. The near-IR region was used because the radiation in this region has insufficient energy to induce a molecular transition to an electronically excited state and hence cause fluorescence. The system comprised of a Nd-YAG laser as a source in conjunction with a Ge detector. In the third part, the computer programs written to increase the capabilities of the data manipulation software are described. In the second section, a comparison is made of the near-IR system with Fourier Transform Raman spectroscopy, this being the most widely used technique used today to overcome the fluorescence problem. A wide range of samples were investigated and conclusions drawn concerning the future applicability of the near-IR dispersive technique. The third section describes the applications of the dispersive system: (a) to study the complexing of BBr₃ with (i) PBr₃ and (ii) P₄S₃; (b) to study, in conjunction with IR spectroscopy, the complexing of Me₂SnCl₂ with a range of pyridine and quinoline derivatives.

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Monothiolate protected gold nanoclusters with near IR luminescence underwent a five-to-ten fold enhancement of quantum efficiency by heating in the presence of excess thiols. Two monothiolate nanoclusters, mercaptosuccinic acid and tiopronin, were shown to benefit from this procedure. Emission maximum around 700-900 nm is favorable for bioimaging applications due to reduction of background signal from autofluorescence. Dithiolate lipoic acid protected gold nanoclusters with higher near IR quantum efficiency present an interesting candidate for biological imaging due to the difference in hydrophobicity, resistance to quenching by divalent cations and cell growth media, and retained quantum efficiency when coupled to agents such as polyethylene glycol. Intracellular and nuclear internalization of mercaptosuccinic gold nanoclusters demonstrate a potential vector for delivery of nuclear targeting agents. The small size, chemical stability, high luminescence, and potential for targeting various intracellular domains make gold nanoclusters worthwhile for further studies as potential bioimaging probes.

Near-IR dyes that absorb and emit in the red visible or near-IR region have attracted great interest in the fields of medicinal chemistry and biochemistry for the last few decades. This interest is due to the multiple notes of metal ions in biological and enviromental processes. Therefore the development of cation selective and sensitive sensors have been a hot subject for many researchers. Consequently, fluorescence based sensors are the most efficient and favorable ones among its counterparts in the field of sensor research. In this study, we have targeted to synthesize BODIPY based near-IR dyes as a selective fluorophore for Zn (II) and Hg (II) cations. We have also demonstrated that the versatile BODIPY fluorophore can be functionalized for long wavelength emission on the 3 and 5 position of the BODIPY core with multiple and distinct functional groups in a stepwise manner. Thus we are able to link two BODIPY cores with a different absorption wavelengths to each other first time with click chemistry strategy to generate a chemosensor for Hg (II) cation.

Cancer remains a global pandemic and is rapidly overtaking other diseases as the no.1 killer in developing nations. Photodynamic therapy (PDT) has been advanced as a minimally invasive cancer therapy. In addition, the emergence of harmful microbes with increasing resistance to drugs has prompted the employment of photodynamic antimicrobial chemotherapy (PACT) as a promising alternative to combat antibiotic resistance. In PDT and PACT, a photosensitizer (dye/drug) upon activation by light transfers energy to molecular oxygen producing singlet oxygen which kills cells. There is increased attention and research into more selective and non-aggregated photosensitizers that will better PDT in treating cancer. This research work is focused on design and synthesis of non-aggregated asymmetric phthalocyanines (dyes) tagged with mitochondrial targeting vehicles to maximize selectivity and photo-killing of tumor cells. Chapter 1 presents a brief review of the current status of PDT and treatment of cancer. The three components of PDT namely, light, oxygen and the photosensitizer, are briefly discussed giving a concise overview of the development of each of them in bettering PDT as an alternative to cancer therapy. Chapter 2 outlines the design, synthesis and characterization of two non-aggregated symmetric ZnPc isomers that have improved water solubility due to incorporation of triethylene glycol groups. The extension of the max absorption to near-IR via non-peripheral substitution on the Pc macrocycle is reported, while comparing the photophysical characteristics of both isomers. Chapter 3 details the improved selectivity of photosensitizers by conjugating ZnPcs to rhodamine B, a delocalized lipophilic cation, which targets the mitochondria of the cell. This conjugation achieved 70% more cell death suggesting that incorporation of rhodamine improved cellular uptake and localization of the photosensitizers which is crucial. Chapters 4 and 5 cover the design, synthesis, characterization, and photodynamic therapy evaluation of ZnPc and phosphorous phthalocyanines. Introduction of phosphorous as an electron deficient central atom promoted a 42 nm bathochromic shift relative to the corresponding ZnPc isomer. Additionally, the effect of peripheral and non-peripheral substitution on phototoxicity of these new compounds is studied and reported. Chapter 5 also gives concluding remarks, and future directions of this work.

Made available in DSpace on 2016-08-19T12:56:36Z (GMT). No. of bitstreams: 1 Leydy Daiana Frazao da Silva.pdf: 3169054 bytes, checksum: 7722a9e052abaed32aab639ad8ea0af9 (MD5) Previous issue date: 2011-04-08 / Oil is a complex mixture whose composition and properties vary according to their origin and composition. Changes in pressure and temperature during production operations and processing can compromise the phase equilibrium of this mixture, resulting in the formation of solid precipitates. The deposition of these fractions can cause blockage of the reservoir and the drainage ducts causing damage to equipment and interfere with the quality of oil produced. Among the major heavy fractions with potential for the formation of deposits are asphaltenes. To treat this problem of asphaltene deposition is necessary to know more about their behavior in different oil samples. To obtain information of these precipitates Near Infrared spectroscopy coupled with Fourier transform was used to determine the onset of asphaltene precipitation in Brazilian petroleum, then these values beginning of precipitation were used to calculate the solubility parameters of the samples, the use of near infrared targets the improvement in the experimental determination of the start point of asphaltene precipitation obtained previously by optical microscopy. The results of solubility parameter obtained by the two techniques were compared. / O petróleo é como uma mistura complexa cuja composição e propriedades variam conforme a sua origem e composição. A deposição dos asfaltenos, frações pesadas do petróleo, durante a prospecção, transporte e processamento são indesejáveis devido aos enormes prejuízos que podem causar. Para compreender o problema de deposição dos asfaltenos é necessário o conhecimento melhor sobre seu comportamento nas diferentes amostras de petróleo. Visando obter mais informações desses precipitados, a Espectroscopia de Infravermelho Próximo acoplada à transformada de Fourier foi utilizada para determinar o ponto de início de precipitação (IP) dos asfaltenos em petróleos brasileiros. Posteriormente, esses valores de inicio de precipitação foram usados para calcular os parâmetros de solubilidade das amostras analisadas. A utilização do infravermelho próximo visa o aprimoramento na determinação experimental do ponto de início de precipitação dos asfaltenos, até então obtido por microscopia óptica. Os resultados mostraram que o ponto de início de precipitação e o parâmetro de solubilidade podem ser obtidos utilizando todo o espectro completo de absorbância, ao invés de utilizar apenas os dados do comprimento de onda de 1600 nm, usualmente empregado na literatura.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18291号 / 工博第3883号 / 新制||工||1596(附属図書館) / 31149 / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 伊藤 紳三郎, 教授 木村 俊作, 教授 辻井 敬亘 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

This dissertation contains the synthesis and characterization of squaraine based new functional materials. In the first part of this thesis work, a water soluble benzothiazolium squaraine dye was synthesized with pyridium pendents, and controlled aggregation properties were achieved. After formation of partially reversible J-aggregation on a polyelectrolyte (poly(acryl acid) sodium salt) template, the nonlinear, two-photon absorption cross section per repeat unit was found to be above 30-fold enhanced compared with nonaggregate and/or low aggregates. Using a similar strategy, sulfonate anions were introduced into the squaraine structure, and the resulting compounds exhibited good water solubilities. A ‘turn on’ fluorescence was discovered when these squaraine dyes interacted with bovine serum albumin (BSA), titration studies by BSA site selective reagents show these squaraine dyes can bind to both site I and II of BSA, with a preference of site II. Introduction of these squaraine dyes to BSA nanoparticles generated near-IR protein nano fabricates, and cell images were collected. Metal sensing properties were also studied using the sulfonates containing a benzoindolium squaraine dye, and the linear response of the absorption of the squaraine dye to the concentration of Hg2+ makes it a good heavy metal-selective sensing material that can be carried out in aqueous solution. Later, a squaraine scaffold was attached to deoxyribonucleosides by Sonogashira coupling reactions, in which the reaction conditions were modified. Iodo-deoxyuridine and bromo-deoxyadenosine were used as the deoxyribonucleosides building blocks, and the resulting squaraine dye-modified deoxyribonucleosides exhibited near-IR absorption and emission properties due to the squaraine chromophore. Interestingly, these non-natural deoxyribonucleosdies showed viscosity dependent photophysical properties, which make them nice candidates for fluorescence viscosity sensors at the cellular level. After incubation with cells, these iv viscosity sensors were readily uptaken by cell, and images were obtained showing regions of high viscosity in cells.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18593号 / 工博第3954号 / 新制||工||1608(附属図書館) / 31493 / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 伊藤 紳三郎, 教授 木村 俊作, 教授 辻井 敬亘 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

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