Este trabalho tem como objetivo sintetizar e caracterizar um novo complexo mononuclear de rutênio (III) e enrofloxacina (enro, fármaco antibacteriano da família das fluoroquinolonas), [Ru(enro)3].nH2O. Foram testadas várias rotas sintéticas e apenas a partir de uma delas obteve-se o composto desejado. O produto foi caracterizado pelas técnicas espectroscópicas de absorção na região do UV-visível e do infra-vermelho. Através desta última técnica foi possível determinar o modo pelo qual a enrofloxacina se coordena ao íon rutênio: a coordenação ocorre de modo bidentado através do oxigênio da piridona e do oxigênio do grupamento carboxilato. Outro objetivo deste trabalho foi investigar a interação do complexo mononuclear de rutênio (III) e norfloxacina, [Ru(nor)3].nH2O, com a albumina de soro humano (HSA), através da técnica de luminescência. Mais especificamente pelo estudo da supressão da luminescência dos resíduos de triptofano, aplicando-se o modelo de tratamento da supressão bimolecular de Stern-Volmer. O estudo de supressão de fluorescência mostrou, por meio de espectros de emissão da HSA, que com o aumento da concentração do complexo [Ru(nor)3].nH2O na solução de HSA, ocorre uma redução gradual da luminescência da HSA, devido a alterações da conformação da proteína, que sugerem alteração do microambiente próximos aos resíduos de triptofano. A partir do tratamento dos dados pode-se determinar tanto K_sv quanto a constante cinética do processo de supressão, que mostraram uma dependência com a temperatura sugerindo como mecanismo predominante de supressão o mecanismo dinâmico. Porém essa conclusão foi revista a partir da determinação dos tempos de vida do estado excitado da HSA, e pode-se concluir que o mecanismo predominante à temperatura ambiente é o mecanismo estático, porém com o aumento da temperatura ocorre a predominância do mecanismo do tipo dinâmico. Através da determinação dos parâmetros termodinâmicos, concluiu-se que as interações entre a HSA e o complexo são espontâneas, e forças de van der Waals e ligações de hidrogênio estão envolvidas na ligação entre a HSA e o supressor. / This work aims to synthesize and characterize a new mononuclear ruthenium (III) complex and enrofloxacin (enro, antibacterial drug of the fluoroquinolone family), [Ru(enro)3].nH2O. Several synthetic routes were tested, but only from one of them it was obtained the desired compound. The product was characterized by spectroscopic techniques of absorption in UV-visible and infra-red regions. Through this last technique, it was possible to determine the coordination mode of enrofloxacin to the ruthenium ion: the coordination occurs in a bidentate way through the pyridone oxygen and the oxygen of the carboxylate group. Another aim of this study was to investigate the interaction of mononuclear ruthenium (III) complex and the norfloxacin, [Ru(nor)3].nH2O, with the human serum albumin (HSA), through the technique of luminescence. More specifically, by the study of the quenching of luminescence of tryptophan residues, by applying the Stern-Volmers model of treatment of bimolecular suppression. The fluorescence quenching study showed, through the emission spectra of HSA, that increasing the complex concentration in HSA solution, there is a gradual reduction of the luminescence of HSA, due to the conformational changes of the protein that suggests the change of microenvironment near tryptophan residues. From the data processing it is possible to determine both K_sv and the kinetic constant of the suppression process, which showed temperature dependence, suggesting as the predominant mechanism of quenching the dynamic mechanism. However, this conclusion has been revised from the determination of the lifetimes of the excited state of HSA, and it can be concluded that the predominant mechanism at room temperature is the static mechanism, but with the temperatures increase, it occurs the predominance of the dynamic type mechanism. By determining the thermodynamic parameters, it was concluded that the interactions between HSA and the complex are spontaneous, and Van der Waals forces and hydrogen bonds are involved in the binding between HSA and suppressor.

Este trabalho tem como objetivo sintetizar e caracterizar um novo complexo mononuclear de rutênio (III) e enrofloxacina (enro, fármaco antibacteriano da família das fluoroquinolonas), [Ru(enro)3].nH2O. Foram testadas várias rotas sintéticas e apenas a partir de uma delas obteve-se o composto desejado. O produto foi caracterizado pelas técnicas espectroscópicas de absorção na região do UV-visível e do infra-vermelho. Através desta última técnica foi possível determinar o modo pelo qual a enrofloxacina se coordena ao íon rutênio: a coordenação ocorre de modo bidentado através do oxigênio da piridona e do oxigênio do grupamento carboxilato. Outro objetivo deste trabalho foi investigar a interação do complexo mononuclear de rutênio (III) e norfloxacina, [Ru(nor)3].nH2O, com a albumina de soro humano (HSA), através da técnica de luminescência. Mais especificamente pelo estudo da supressão da luminescência dos resíduos de triptofano, aplicando-se o modelo de tratamento da supressão bimolecular de Stern-Volmer. O estudo de supressão de fluorescência mostrou, por meio de espectros de emissão da HSA, que com o aumento da concentração do complexo [Ru(nor)3].nH2O na solução de HSA, ocorre uma redução gradual da luminescência da HSA, devido a alterações da conformação da proteína, que sugerem alteração do microambiente próximos aos resíduos de triptofano. A partir do tratamento dos dados pode-se determinar tanto K_sv quanto a constante cinética do processo de supressão, que mostraram uma dependência com a temperatura sugerindo como mecanismo predominante de supressão o mecanismo dinâmico. Porém essa conclusão foi revista a partir da determinação dos tempos de vida do estado excitado da HSA, e pode-se concluir que o mecanismo predominante à temperatura ambiente é o mecanismo estático, porém com o aumento da temperatura ocorre a predominância do mecanismo do tipo dinâmico. Através da determinação dos parâmetros termodinâmicos, concluiu-se que as interações entre a HSA e o complexo são espontâneas, e forças de van der Waals e ligações de hidrogênio estão envolvidas na ligação entre a HSA e o supressor. / This work aims to synthesize and characterize a new mononuclear ruthenium (III) complex and enrofloxacin (enro, antibacterial drug of the fluoroquinolone family), [Ru(enro)3].nH2O. Several synthetic routes were tested, but only from one of them it was obtained the desired compound. The product was characterized by spectroscopic techniques of absorption in UV-visible and infra-red regions. Through this last technique, it was possible to determine the coordination mode of enrofloxacin to the ruthenium ion: the coordination occurs in a bidentate way through the pyridone oxygen and the oxygen of the carboxylate group. Another aim of this study was to investigate the interaction of mononuclear ruthenium (III) complex and the norfloxacin, [Ru(nor)3].nH2O, with the human serum albumin (HSA), through the technique of luminescence. More specifically, by the study of the quenching of luminescence of tryptophan residues, by applying the Stern-Volmers model of treatment of bimolecular suppression. The fluorescence quenching study showed, through the emission spectra of HSA, that increasing the complex concentration in HSA solution, there is a gradual reduction of the luminescence of HSA, due to the conformational changes of the protein that suggests the change of microenvironment near tryptophan residues. From the data processing it is possible to determine both K_sv and the kinetic constant of the suppression process, which showed temperature dependence, suggesting as the predominant mechanism of quenching the dynamic mechanism. However, this conclusion has been revised from the determination of the lifetimes of the excited state of HSA, and it can be concluded that the predominant mechanism at room temperature is the static mechanism, but with the temperatures increase, it occurs the predominance of the dynamic type mechanism. By determining the thermodynamic parameters, it was concluded that the interactions between HSA and the complex are spontaneous, and Van der Waals forces and hydrogen bonds are involved in the binding between HSA and suppressor.

No description available.

<p> A noninvasive method using fluorescence quenching (FQ) to determine the conditional stability constants (logK') for aluminum with naturally occurring organic ligands has been developed. The method utilizes the Stern-Volmer equation to interpret data from ligand fluorescence suppression by aluminum. The total ligand concentration can also be determined using the measured stability constant and the Ryan-Weber equation. The method has been validated with the model ligand salicylic acid; logK' was found to be 3.5 ± 0.01 vs. 4.0 from the literature. The method was applied to the reference ligand Armadale fulvic acid and chemically realistic values were obtained. In addition, the expected trend of increasing stability constant with decreasing pH was observed. The method was further validated by determining the stability constant for Armadale fulvic acid using an independent technique, PCV colourimetry; the results agreed very well logK' = 4.7 vs. 4.65 for FQ analysis. Application of the method to whole filtered beaver pond water showed an increasing trend in the stability constant as the dissolved organic carbon (DOC) decreased. The Log of the stability constants were 3.15 ± 0.03, 3.26 ± 0.03, and 3.63 ± 0.02 for DOC concentrations 23, 14, and 10 ppm respectively. The method was also applied to size fractionated waters form lake Skjervatjern in Norway and the expected trend of increasing stability constant with increasing molecular weight was observed.</p> / Thesis / Bachelor of Science (BSc)

[pt] As nanopartículas semicondutoras (pontos quânticos ou QDs), na forma de dispersões coloidais aquosas, foram usadas como sondas para determinação indireta de flavonóides. As características especiais desses materiais, decorrente do efeito de confinamento quântico alcançado nas estruturas cujas dimensões são da ordem de poucos nm de diâmetro, resultam em propriedades fotofisicas únicas que podem ser alteradas pelo ajuste do tamanho e/ou na modificação da superfície destes nanocristais. Uma vez que os flavonóides não fluorescem naturalmente, nanopartículas de CdS modificadas com ácido 2-mercaptopropiônico (sonda dos QDs de 2MPA-CdS) e de CdTe modificadas com ácido 3-mercaptopropiônico (sonda dos QDs de 3MPA-CdTe) foram sintetizadas em fase aquosa coloidal e usadas para a determinação indireta de rutina (RUT) e de quercetina (QUE) por meio de medição de decréscimo da fotoluminescência das sondas. A utilização dos QDs como sensores na quantificação destes compostos permitiu a realização de medições fotoluminescentes rápidas e simples, sem a necessidade do uso de complexos procedimentos de derivatização química, usulamente indicados para estes casos. Verificou-se, através do modelo de Stern-Volmer, que o sinal fotoluminescente dos QDs de 2MPA-CdS é atenuado pela presença de RUT, e esta supressão de sinal foi proporcional à concentração de analito na dispersões coloidas (faixa de resposta linear entre 0,5 e 4,0 x 10-5 mol L-1), com limite de detecção (LD) de 1,2 x 10-6 mol L-1. Observou-se também que a supressão de sinal fotoluminescente foi uma combinação da contribuição do efeito filtro (devido à absorção de parcial de radiação pelo analito no comprimento de onda de excitação) e de supressão estática (proveniente da ligação e troca de energia entre analito e QDs). A abordagem foi usada na determinação seletiva de RUT em formulação farmacêutica e em amostras simuladas contendo RUT e QUE ou em saliva fortificada com RUT, nesses dois últimos casos foi associando um método a uma separação prévia de componentes por cromatografia de camada fina. A seletividade em relação a outros flavonóides também foi avaliada. A sonda de 3MPA-CdTe QDs foi usada para a determinação de QUE tanto na dispersão original quanto na dispersão organizada por surfactente (brometo de cetiltrimetilamônio ou CTAB). A QUE foi quantificada em meio não organizado e o método aplicado na análise de suplemento contendo QUE e ácido ascórbico e na análise de extratos de cebolas roxa e amarela. A técnica de cromatografia de camada fina foi utilizada com o intuito de separar a QUE de interferentes presentes na cebola. O modelo de Stern-Volmer foi utilizado para estabelecer uma relação linear entre a fotoluminescência medida na dispersão dos QDs e a quantidade de QUE adicioanda na dispersão. A curva analítica cobriu a faixa de concentrações de QUE entre 0,5 a 6,0 x 10-5 mol L-1 com LD de 0,5 x 10-5 mol L-1. Estudos realizados indicaram que a natureza do quenching formado é estático. Finalmente, um estudo sistemático da interação entre diversos flavonóides e o QDs de 3MPA-CdTe foi estudado de modo a se estabelecer a função do surfactante CTAB no processo de interação entre sonda e supressor. Verificou-se maior estabilidade de sinal da sonda neste meio, e interaçōes analito-QDs distintas daquelas obtidas na ausência do surfactante. / [en] The semiconductor nanoparticles (quantum dots or QDs), in the form of aqueous colloidal dispersions, were used as probes for the indirect determination of flavonoids. The special characteristics of these materials, due to the quantum confinement effect achieved in structures whose dimensions are of the order of a few nm, in diameter, result in unique photophysical properties that can be changed by adjusting the size and/or by surface modification of these nanocrystals. Since flavonoids do not present natural fluorescence, CdS nanoparticles modified with 2-mercaptopropionic acid (2MPA-CdS QDs probe) and CdTe modified with 3-mercaptopropionic acid (3MPA-CdTe QDs probe) have been synthesized in colloidal aqueous phase and used for indirect determination of rutin (RUT) and quercetin (QUE) by measuring the photoluminescence decreasing from the probes. The use of QDs as probes for the quantification of these compounds has allowed the quick and simple photoluminescence measurements without the need for complex chemical derivatization procedures, usually indicated in these cases. It was found, through the Stern-Volmer model, that the photoluminescence of the 2MPA-CdS QDs is attenuated by the presence of RUT, and such a signal suppression was proportional to the concentration of analyte in colloidal dispersion (linear response range between 0,5 to 4.0 x 10-5 mol L-1), with limit of detection (LOD) of 1.2 x 10-6 mol L-1. It was also observed that photoluminescence suppression was a combination of the contribution of inner filter effect (due to partial radiation absorption by the analyte at the wavelength of excitation) and static supression (from the binding and energy exchange between analyte and QDs). The method was used to the selective determination of RUT in pharmaceutical formulation and in simulated samples containing QUE/RUT and/or saliva fortified with RUT. For these former two samples, thin layer chromatography was used to establish prior separation of components. The selectivity towards other flavonoids was also evaluated. The 3MPA-CdTe QDs probe was used to determine QUE in original dispersion and in dispersion containing surfactant (cetyltrimethylammonium bromide or CTAB). QUE was quantified in a non-organized environment (without surfactant) and the method was applied for the analysis in supplement containing QUE and ascorbic acid and for the analysis of purple and yellow onions. Thin layer chromatography was used in order to separate interfering present in onions. The Stern-Volmer model was used to establish a linear relationship between the photoluminescence measurement of the QDs dispersion and the amount of QUE added into the dispersion. The analytical curve covered the range of concentrations between 0.5 to 6.0 x 10-5 mol L-1 of QUE with LD 0.5 x 10-5 mol L-1. Studies indicate that the nature of formed quenching is static. Finally, a systematic study of the interaction between various flavonoids and CdTe-3MPA QDs was studied in order to establish the CTAB surfactant function in the interaction between probe and quencher. It was observed more signal stability of the probe in this medium, and interactions distinct analyte-QDs from those obtained in the absence of surfactant.

Metallhalogenid-Perowskite (MHPs) sind Halbleiter, die einzigartige photophysikalische Eigenschaften aufweisen, die sie ideal für photovoltaische Anwendungen machen. Techniken werden kontinuierlich entwickelt, um die Leistungsgrenzen der Perowskite weiter zu verschieben. Dennoch weisen diese Materialien verschiedene Herausforderungen auf. Zu diesen gehören eine geringe Stabilität unter einer Vielzahl von äußeren Bedingungen, sowie eine große Diskrepanz zwischen den Wirkungsgraden von Geräten im Labormaßstab und großflächigen Geräten. Zunächst wurden mit Hilfe von Photolumineszenz-Spektroskopie Ladungsübertragungsmechanismen zwischen MHPs und atmosphärischen Gasen untersucht, um deren Einfluss auf die Materialstabilität zu bestimmen. Durch den Vergleich der Emission von verschiedene MHP wurde die Wirkung untersucht, die atmosphärische Gase auf Grenzdefekte im Material haben. Diese Löschungseffekte wurden nachfolgend mit dem Stern-Volmer-Modell analysiert. Es stellte sich heraus, dass ein Teil von der Gase bindet jedoch an die MHPs, wobei teilweise Kristalldefekte passiviert werden und für jedes der Gase Ladungstransfermechanismen vorgeschlagen wurden. Zweitens wurde die Skalierung von MHP-Bauelementen mittels Tintenstrahldruck untersucht. Dazu wurden drei Kristallisationstechniken ausgewertet. Eine davon verwendete eine sequenzielle Abscheidung von zwei Präkursortinten, während die beiden anderen kristallisierte Tinten verwendeten, die in einem Schritt abgeschieden wurden. Die letztgenannten Techniken verwendeten beide niedrige Drücke und bei einer wurde ein kontrollierter Stickstoffstrom auf die Probe angewendet. Solarzellen mit einer Effizienz von 16,8% auf einer Fläche von 0,16 cm² wurden demonstriert. Diese Ergebnisse zeigen ein neuartiges Verfahren zur Untersuchung von strahlungslosen Verlustwegen in MHPs auf. Zusätzlich demonstrieren diese Studien, dass der Tintenstrahldruck eine geeignete Technologie ist, um MHP-Bauelemente zu skalieren. / Metal halide perovskites (MHPs) are semiconductor materials that show unique photophysical properties, making them ideal for photovoltaic applications. Having shown power conversion efficiencies of up to 25.5%, techniques are continuously being developed to push perovskites to unprecedent limits. Yet, these materials present challenges like a low stability under a variety of conditions as well as a large disparity between the efficiencies of lab scale and large area devices. This thesis addresses these two major obstacles. First, charge transfer mechanisms between MHPs and atmospheric gases were studied to determine their effect on the material stability by using photoluminescence spectroscopy. By comparing the emission of MHPs, the effect that molecular oxygen, nitrogen, argon, and water have on boundary defects in the material was studied. These quenching effects were later analyzed using the Stern-Volmer model. It was found that the gases bounce off the surface, but a portion of them bind to the MHPs, in occasions passivating defects on the crystals. Using these results, charge transfer mechanisms were proposed for each one of the gases. Second, scaling of MHP devices was examined using inkjet printing. For this, three crystallization techniques were evaluated. One of them used sequential deposition of two precursor inks, while the other two crystallized ink that was deposited in one step. Both latter techniques used low pressures, below 1 mbar, and only one of them applied a controlled stream of nitrogen to the sample. Using these techniques, the deposition of a 15x15 cm² area as well as a device with an efficiency of 16.8% on an area of 0.16 cm² were demonstrated. These results show a novel procedure to study non-radiative loss paths in MHPs to enhance their stability and performance as devices. Also, they show that inkjet printing is a favorable technology to scale MHP devices and eventually facilitate the mass production of this type of photovoltaic devices.

A new technique is developed that uses planar laser-induced fluorescence (PLIF) imaging of sublimated naphthalene to image the transport of ablation products in a hypersonic boundary layer. The primary motivation for this work is to understand scalar transport in hypersonic boundary layers and to develop a database for validation of computational models. The naphthalene is molded into a rectangular insert that is mounted flush with the floor of a Mach 5 wind tunnel. The distribution of naphthalene in the boundary layer is imaged by using PLIF, where the laser excitation is at 266 nm and the fluorescence is collected in the range of 320 to 380 nm. To investigate the use of naphthalene PLIF as a quantitative diagnostic technique, a series of experiments is conducted to determine the linearity of the fluorescence signal with laser fluence, as well as the temperature and pressure dependencies of the signal. The naphthalene fluorescence at 297 K is determined to be linear for laser fluence that is less than about 200 J/m². The temperature dependence of the naphthalene fluorescence signal is found at atmospheric pressure over the temperature range of 297K to 525K. A monotonic increase in the fluorescence is observed with increasing temperature. Naphthalene fluorescence lifetime measurements were also made in pure-air and nitrogen environments at 300 K over the range 1 kPa to 40 kPa. The results in air show the expected Stern-Volmer behavior with decreasing lifetimes at increasing pressure, whereas nitrogen exhibits the opposite trend. Preliminary PLIF images of the sublimated naphthalene are acquired in a Mach 5 turbulent boundary layer. Relatively low signal-to-noise-ratio images were obtained at a stagnation temperature of 345 K, but much higher quality images were obtained at a stagnation temperature of 380 K. The initial results indicate that PLIF of sublimating naphthalene may be an effective tool for studying scalar transport in hypersonic flows. / text

No description available.

Une série de dimères composés de thiophène-aniline encombrée stériquement a été synthétisée. Les différents processus de désactivation de l’état singulet excité ont été étudiés par UV-visible, fluorescence, phosphorescence, photolyse par impulsion laser et calculs théoriques. Les graphiques de Stern-Volmer obtenus à partir des expériences de désactivation des états singulet et triplet ont démontré l’efficacité de l’azométhine à désactiver les fluorophores. Les calculs semi-empiriques AM1 examinant l’effet des substituants encombrés ont démontrés que les groupements tert-butyls sur l’aniline ont moins d’influence sur la barrière de rotation N-aryl que les substitutions alkyles en ont sur la rotation de thiophène-C. Les calculs Rehm-Weller basés sur les potentiels d’oxydation et de réduction ont montré que l’autodésactivation de l’état excité des azométhines se fait par transfert d’électron photoinduit menant à une éradication complète de la fluorescence. Des complexes métalliques contenant des ligands azométhines ont aussi été préparés. Le ligand est composé d’une unité hydroxyquinoline lié à un cycle thiophène. Les données photophysiques de ces complexes indiquent un déplacement bathochromique aussi bien en absorbance qu’en fluorescence. Des dispositifs de détection d’ion métallique ont été préparés et un exemple à partir d’une solution de cuivre a montré un déplacement bathochromique. / A series of sterically hindered thiophene-aniline azomethine dyads were prepared. The decay pathways that deactivate the singlet excited state were studied using UV-vis fluorescence and phosphorescence, laser flash photolysis and quantum calculations. Stern-Volmer relationships, derived from singlet and triplet state quenching experiments, showed that azomethines efficiently deactivate the singlet and triplet excited states of fluorophores with bimolecular kinetics. AM1 Semi-empirical quantum calculations examining the effect of bulky substituents on the bond rotational barriers demonstrate that bulky tert-butyl groups attached to the aniline moiety have less influence on the N-aryl bond rotation barrier than alkyl substitutions do on the thiophene-CH bond rotation barrier. Rehm-Weller calculations based on electrochemical potentials demonstrate that azomethines self-quench their excited states via fast and efficient intramolecular photoinduced electron transfer leading to complete fluorescence suppression. Metal complexes containing an azomethine ligand were also prepared. The ligand contains a hydroxyquinoline moiety linked with a thiophene ring. Photophysical investigations of the resulting metal complexes demonstrated significant bathochromic shifts in the absorbance and fluorescence spectra. Metal-ion sensing devices for water solutions were prepared by spin casting the ligand onto glass slides. The metal-ion sensor detected copper in water solutions through a bathochromic shift in the absorbance maximum.

No description available.