This paper deals with 3-picoline, 4-picoline, 3,4-lutidine and 3,5-lutidine complexes of copper(I) iodide (CuI(3-pic), CuI(4-pic), CuI(3,4-lut) and (CuI(3,5-lut)). The experimental investigation was divided into several parts. Firstly, the synthesis and characterization of the compounds both as powder and as thin films. Secondly, the photoluminescence study. Thirdly, the observation of ligand exchange reaction by vapor diffusion, and lastly, the determination of the lifetime by time-resolved photoluminescence of respective compound.  All studied copper(I)-iodide-substituted pyridine compounds were emissive both as powders and thin films. The synthesis of the tetranuclear cluster powders yields both cluster and polymeric forms of structure. The pXRD of the powders CuI(3-pic), CuI(4-pic), and CuI(3,5- lut) confirmed to be as polymeric structures, hence the CuI(3-pic) showed thermochromism behavior. The structure of CuI(3,4-lut) is still unconfirmed. The most effective method for the synthesis of the thin films was the SILAR method.  The photoluminescence spectra of respective thin films differ from their corresponding powders, and the structure of the compounds as thin films is yet unexplored. The emission of CuI(3-pic), CuI(4-pic), and CuI(3,4-lut) as thin films were similar 480nm, hence the emission of CuI(3,5-lut) thin film lays on 518 nm. Therefore, the ligand exchange reaction was performed on the CuI(3-pic) thin film with 3,5-lutidine as the exchanging ligand.  The ligand exchange reaction of CuI(3-pic) thin film by vapor diffusion of 3,5-lutidine results in a spectrum shift from the emission spectrum of CuI(3-pic) to the spectrum of CuI(3,5-lut). This indicates a successful ligand exchange reaction by vapor diffusion.  The lifetimes of the investigated compounds which have their best fit of mono-exponential function were between 2,2 μs and 9,52 μs. The lifetimes were determined on the thin films with time-resolved photoluminescence. The ligand exchange reaction was also observed by time- resolved photoluminescence which reveals some stable lifetimes during the reaction that can indicate the formation of intermediates. In contrast, the measured lifetimes during the ligand exchange reaction have their best fit of bi-exponential function which can be due to reaction conditions during the measurement or the homogeneity of the thin films. / Denna uppsats behandlar 3-pikolin, 4-pikolin, 3,4-lutidin och 3,5-lutidin komplex av koppar(I) jodid (CuI(3-pic), CuI(4-pic), CuI(3,4-lut) och (CuI(3,5-lut)). Den experimentella undersökningen delades in i olika delar. Först, syntesen och karakteriseringen av föreningarna både som pulver och som tunn film. Sedan studerades fotoluminiscensen av respektive förening. Därefter genomförde en ligand-utbytes-reaktion genom förgasning och slutligen bestämde livstiden av föreningarnas exciterade tillstånd.  Alla koppar(I) jodid föreningar som studerade gav upphov till emission både som pulver och som tunn film. Syntesen av tetranukleära kluster i pulverform resulterade i både kluster och polymer struktur. pXRD av pulvren CuI(3-pic), CuI(4-pic) och CuI(3,5-lut) bekräftade dess struktur som polymera strukturer. Däremot visade CuI(3-pic) termokromism. Strukturen för CuI (3,4-lut) kunde inte obekräftas. Den mest effektiva metoden för syntes av tunn film i det här fallet är med SILAR-metoden.  Fotoluminescensspektra för respektive tunn film skiljer sig från deras motsvarande pulverform och strukturen på tunn film är fortfarande outforskat. Emission av CuI(3-pic), CuI(4-pic) och CuI(3,4-lut) som tunn film var ungefär lika ~480 nm medan för CuI(3,5-lut) så var det på 518 nm. Med denna kontrast utfördes ligand-utbyte-reaktionen på tunn film av CuI(3-pic) med 3,5- lutidin.  Ligand-utbyte-reaktionen av CuI(3-pic) på tunn film via förgasning av 3,5-lutidin resulterar i en spektrumförskjutning från spektrumet av CuI(3-pic) till spektrumet av CuI(3,5-lut). Detta indikerar i en lyckad ligand-utbyte-reaktion.  Livslängderna för de undersökta föreningarna vilket har sin bästa passning i mono- exponentiell funktion var mellan 2,2 μs och 9,52 μs. Livstiderna bestämdes på de tunn film med ”time-resolved photoluminescence”. Ligand-utbyte-reaktionen observerades också med ”time- resolved photoluminescence” som avslöjar några stabila livstider under reaktionen vilket kan indikera bildning av intermedianer. De uppmätta livstiderna under ligand-utbyte-reaktionen har däremot sin bästa passning av bi-exponentiell funktion vilket kan bero på reaktionsförhållanden under mätningen och tunn filmernas homogenitet.

<p>Photodynamic therapy (PDT) is a rapidly developing clinical treatment modality involving a light-activatable photosensitizer, tissue oxygen and light of an appropriate wavelength to generate cytotoxic reactive molecular species - primarily singlet oxygen (¹O₂). Singlet oxygen readily reacts with surrounding biomolecules leading to different biological effects and subsequent therapeutic outcomes. Over the last decades, many standard PDT treatments have been approved worldwide to treat different medical conditions ranging from a variety of cancer conditions to age-related macular degeneration (AMD). Meanwhile, many active clinical trials and pre-clinical studies are underway for other clinical indications. The therapeutic outcomes of PDT are difficult to predict reliably even with many years of research. The fundamental cause for this is the inherent complexity of PDT mechanisms. As PDT involves three main components, the outcomes of PDT are determined by the combination of all components. Each component varies temporally and spatially during PDT, and the variations are mutually dependent on each other. Moreover, components such as the photosensitizer can have great variations in their initial distribution among patients even before PDT treatment. Given this, no well accepted standard PDT dose metric method has been recognized in clinics, although different approaches including explicit, implicit and direct dosimetry have been studied. To tackle the inherently complicated PDT mechanism in order to provide insights into PDT and PDT dosimetry, a theoretical one-dimensional model for aminolevulinic acid (ALA) induced protoporphyrin IX (PpIX)-PDT of human skin was developed and is presented in this thesis. The model incorporates major photophysical and photochemical reactions in PDT, and calculated temporal and spatial distributions of PDT components as well as the detectable emission signals including both sensitizer fluorescence and singlet oxygen luminescence (SOL) using typical clinical conditions. Since singlet oxygen is considered to cause PDT outcomes, the correlations of different PDT dose metrics to average reacted (¹O₂) "dose" and "dose" at different depths were examined and compared for a wide range of varied treatment conditions. The dose metrics included absolute fluorescence bleaching metric (AFBM), fractional fluorescence bleaching metric (FFBM) and cumulative singlet oxygen luminescence (CSOL), and the varied treatment conditions took into account different treatment irradiances and wavelengths, varied initial sensitizer concentration and distribution, and a wide range of optical properties of tissue. These investigations and comparisons provide information about the complicated dynamic process of PDT such as the induction of tissue hypoxia, photosensitizer photobleaching and possible PDT-induced vascular responses. It was also found that the CSOL is the most robust and could serve as a gold standard for the testing of other techniques. In addition to these theoretical studies, recent progress on the assessment of a novel, more efficient superconducting nanowire single photon detector (SNSPD) for singlet oxygen luminescence detection will be introduced and the current photomultiplier tubes (PMT) system will be briefly described as well. The author participated in the experimental assessments of the SNSPD and analyzed the results shown in this thesis.</p> / Doctor of Philosophy (PhD)

Biogenic monoamines such as dopamine play an important role as major neurotransmitters. Simultaneous determination of the concentration changes is thus crucial to understand brain function. Additionally, quantification of pharmaceutically active compounds (PhACs) and their metabolites in biological fluids is an important issue for forensic tests, clinical toxicology and pharmaceutical analysis. We have developed two postcolumn luminescence detection methods coupled to a 2-dimensional-solid phase extraction (2D-SPE) system. The postcolumn reaction methods used in this study are the redox-dependent photoluminescence-following electron-transfer (PFET) and Fenton-based chemiluminescence techniques, for the determination of certain neurotransmitter and nonsteroidal anti-inflammatory drugs (NSAIDs). A stable [Os(tmphen)3]3+ (tmphen = 3,4,7,8-tetramethyl-1,10-phenanthroline) reagent was prepared in neutral aqueous solution by oxidation of [Os(tmphen)3]2+ with lead(IV) oxide. [Os(tmphen)3]2+ and [Os(tmphen)3]3+ are characterized by absorption spectroscopy. [Os(tmphen)3]3+ stability is compared with [Ru(tmphen)3]3+ in the same pH 7 environment. The properties of Os(III) and Ru(III) complexes were investigated for use as the oxidant in a PFET system. Studies of photophysical and electrochemical properties, the stability of the Os(III) and Ru(III) complexes, and analytical application in PFET detection of oxidizable analytes are presented. The spectroscopic properties of the complexes were not very advantageous, but careful control of the detection system and reaction conditions enabled sensitive detection of the analytes. The method was fully validated and the optimized system was capable of detecting dopamine and acetaminophen at about 30.2 µg L-1 and 33.5 µg L-1, respectively. The limit of detection (LOD) was 1.5 µg L-1 for acetaminophen and 4.3 µg L-1 for dopamine. The accuracy and precision were within bioanalytical method validation limits (90.9 to 101.5 % and RSD &lt; 12.0 %, respectively). Typical analysis time was less than 15 minutes. Two Fenton-based flow-injection chemiluminescence (CL) methods were developed and validated for the determination of naproxen. Under the optimal experimental conditions the proposed methods exhibited advantages in a larger linear range from 2,760 ng mL-1 to 207,000 ng mL-1 for the first CL method and 41.4 ng mL-1 to 700.0 ng mL-1 for the second CL method. The LOD was 13.8 ng mL-1 for naproxen. The CL mechanisms for the system, H2O2-FeIIEDTA-naproxen was further studied by batch experiments, chemiluminescence spectroscopy, fluorometry, high pressure liquid chromatography (HPLC) and Fourier transform infrared spectroscopy (FTIR). The effects of various interferences commonly found in biological and wastewater systems on the chemiluminescence intensity were also investigated. We used these methods to determine NSAIDs in commercial pharmaceutical formulations. Another application of these method was for detecting NSAIDs in biological samples. A 2x-1-Dimensional Solid Phase Extraction (2x-1D SPE) method was developed for determination of acetaminophen and naproxen in urine. This method uses both the methanol concentration and the pH advantageously to preferentially isolate analytes of interest from complex sample matrix. These methods were fully validated and had sufficient sensitivity (limit of quantification: acetaminophen; 40.41 mg L-1 - 360.0 mg L-1 and naproxen; 23.03 mg L-1 - 214.8 mg L-1) for biological matrices and applications. / Chemistry

McMaster University DOCTOR OF PHILOSOPHY (2017) Hamilton, Ontario (Engineering Physics) TITLE: Luminescent Silicon Carbonitride Thin Films Grown using ECR PECVD: Fabrication and Characterization AUTHOR: Zahra Khatami , M.A.Sc. (Shahid Behehsti University) SUPERVISOR: Professor Peter Mascher NUMBER OF PAGES: xx, 268 / Silicon, the cornerstone semiconductor of microelectronics, has seen growing interest as a low-cost material in photonics. Nanoscience has employed various strategies to overcome its fundamentally inefficient visible light emission such as developing new silicon-based nanostructures and materials. Each of the proposed materials has its own advantages and disadvantages in attempting to reach commercialization. Silicon carbonitride (SiCxNy) is a less-studied and multi-functional material with tunable optical features. Despite reports on promising mechanical properties of SiCxNy thin films, they have not yet been well explored optically. This thesis presents the first in-depth analysis of the luminescent properties of SiCxNy thin films at a broad range of compositions and temperatures. To better understand this ternary structure, the reported data of the two fairly well studied binary structures was used as a reference. Therefore, three classes of silicon-based materials were produced and explored; SiCxNy, SiNx, and SiCx. Samples were fabricated using one of the common methods in the semiconductor industry; electron cyclotron resonance plasma enhanced chemical vapour deposition (ECR PECVD). A multitude of characterization techniques were utilized including; optical methods (ultraviolet-visible spectroscopy (UVVIS), variable angle spectroscopic ellipsometry (VASE), photoluminescence (PL)) and structural techniques (elastic recoil detection (ERD), Rutherford backscattering spectrometry (RBS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), high-resolution transmission electron microscopy (HR-TEM)). In view of the exploring of emission properties of SiCxNy materials, our approach was towards the enhancement of the visible emission by adjusting the film composition and subsequent thermal treatment. First, a systematic study of the influence of carbon on the optical, compositional, and structural properties of SiCxNy was carried out. This investigation was followed by an exploration of influence of growth conditions on the visible emission and its connection with the other film properties including hydrogen concentration, microstructure, and composition. In addition, hydrogen diffusion was explored and associated with two featured annealing temperatures. The key element of this thesis is the comprehensive report on the interdependency of the visible light emission and all optical, structural, and compositional features of SiCxNy structures. Unlocking the potential of this ternary and less studied material can appeal to the silicon photonics community to implement it in anti-reflection, solar cell, and sensing applications, and in particular as a substitution of SiNx used in existing microelectronic devices. / Thesis / Doctor of Philosophy (PhD)

"Thèse en cotutelle, doctorat en chimie :Université Laval, Québec, Canada, Philosophiae doctor (Ph.D.) et São Paulo State University, Araraquara, Brazil, Docteure" / Dans le domaine biomédical, il y a une demande croissante pour les nanosystèmes multifonctionnels pour effectuer simultanément l'imagerie et la thérapie, en visant le diagnostic précoce et apporter du bénéfice thérapeutique maximal. Les nanoparticules à conversion ascendante d’energie (UCNPs) ont été proposés comme une bio-sonde idéale en raison de leurs avantages uniques liés au phénomène d'upconversion présenté par les matériaux contenant des ions lanthanides, c’est-à-dire l’émission visible obtenue sous excitation dans le proche infrarouge (NIR), tels qu’une meilleure pénétration dans les tissus, une bas taux d’autofluorescence et un photo-dommage minimal. De plus, les propriétés luminescentes des ions lanthanides peuvent être utilisées pour la thermométrie en raison de leur forte dépendance sur la température. La thermométrie par luminescence est une technique sans contact et à haute résolution qui a attiré l'attention en nanomédecine puisque la température est un paramètre clé dans le fonctionnement des cellules. Des dommages thermiques aux cellules peuvent être localement photoinduits par l'utilisation de nanostructures métalliques illuminées dans leur bande de résonance plasmon en raison de leur absorptivité élevée. La prémière partie de ce travail implique le développement d'un système multifonctionnel, basé sur des nanocoquilles d’or (AuNSs) décorées avec des UCNPs, pouvant être utilisé pour augmenter et mesurer la température à l'échelle nanométrique. Ce système a été développé dans le but d’éventuelle utilisation comme agent de thérapie photothermique (PTT), dans laquelle la capacité thermométrique des UCNPs permettra d'optimiser les bénéfices thérapeutiques. La synthèse des UCNPs de NaGdF4 dopées avec les ions Yb3+ et Er3+ a été réalisée par décomposition thermique des précurseurs de fluorure de lanthanide à des températures elévées (> 300 °C) en présence d'un ligand de coordination (l’acide oléique). Les UCNPs ont été synthétisées à trois températures différentes (310, 315 et 320 °C) et caractérisées selon leurs propriétés morphologiques, structurelles et émissives. Compte tenu des applications biologiques prévues, la surface hydrophobe des UCNPs recouverte de chaînes oléate a été modifiée par un revêtement de silice par un processus Stöber modifié au moyen d'une méthode de microémulsion inverse afin d'obtenir une dispersion suffisante dans l'eau. Des nanocristaux monodisperses de NaGdF4:Yb3+:Er3+ à conversion ascendante (~ 25 nm de diamètre) ont été obtenus en phases cubique (à 310, 315 °C) et hexagonale (à 320 °C). Les UCNPs dans la phase hexagonale étaient plus appropriés en tant que capteurs de température en raison du rapport faible entre les émissions rouge/vert et une plus grande sensibilité thermique. Le spectre d'émission des UCNP (recouvertes de silice ou d'oléate) a été enregistré à des températures différentes à proximité de la plage physiologique (20–70 °C) et il a présenté des propriétés appropriées pour leur utilisation comme capteur de température, notamment une excellente linéarité (R2 > 0,99) et une bonne sensibilité (>3 × 10−3 K−1). La surface des AuNS a été décorée avec des UCNP recouvertes de silice. La capacité de chauffage des AuNSs@UCNPs a été vérifiée en mesurant l'émission de l'Er3+, ce qui démontre leur potentiel d'application comme agent d'hyperthermie contrôlée par l'utilisation de la fonction de nanothermomètre. La deuxième partie de ce projet de thèse a été consacrée au développement d'un nanosystème multifonctionnel pouvant être utilisé comme un système de double capture de lumière UV et de mesure de température. Le complexe Eu(tta)3 (tta-thénoyltrifluoreacetonate) a été préparé in situ dans la coquille de silice des UCNPs de NaGdF4:Yb3+:Er3+. Un nanothermomètre à double mode a été obtenu à partir du signal de fluorescence généré grâce à la conversion ascendante (proche infrarouge → visible) par les ions Er3+ ainsi que par l’émission par la conversion descendante excitée dans l'UV du complexe Eu(tta)3. Les mesures ont été prises près de la plage de température physiologique (20—50 °C) et montrent une excellente linéarité (R2 > 0,99) et une sensibilité thermique relativement élevée (≥1,5%·K−1). L’utilité du complexe Eu(tta)3 présent dans la coquille de silice comme capteur de la lumière UV a été démontré par la dépendance de la luminescence de l’ion Eu3+ sur la durée de l'exposition à la lumière UV. Le matériau obtenu présente un potentiel d'application dans les thérapies activées par la lumière, telles que la thérapie photodynamique (PDT) et la PTT, qui nécessitent généralement une lumière UV ou bleue pour l'excitation. Le contrôle de la dose de lumière delivrée aux tissus a une grande importance dans ces procédures thérapeutiques pour éviter le photodommage aux tissus environnants. La fonction thermomètre est utile pour guider de tels processus (PDT et PTT) en synergie avec le dosimètre d’UV. / In the biomedical field, there is an increasing demand for multifunctional nanosystems to perform imaging and therapy simultaneously, aiming at early diagnosis and maximum therapeutic benefit. Upconversion nanoparticles (UCNPs) have been proposed as an ideal bio-probe because of their unique advantages related to the upconversion phenomenon presented by materials containing lanthanide ions, e.g. visible emission obtained under near-infrared (NIR) excitation, such as deep tissue penetration, low autofluorescence background and low photo-damage. Moreover, the luminescent properties of lanthanide ions may be used for thermometry because of a strongly temperature-dependent effect. Luminescence nanothermometry is a noncontact and high-resolution technique that has been gaining attention in nanomedicine since temperature is a fundamental parameter in events that occur in cells. The thermal damage of cells may be locally photoinduced by using metal nanostructures illuminated at their localized surface plasmon resonance (LSPR) band because of the enhancement of light absorption. In this work, a multifunctional system was designed combining gold nanoshells (AuNSs) and UCNPs intended as an optical heater and temperature probe at the nanoscale. This system was studied aiming its application as an agent for photothermal therapy (PTT), guided by the thermometer capacity of UCNPs, which allows to optimize the therapeutic benefits. The synthesis of NaGdF4 UCNPs doped with ions Yb3+:Er3+ was performed via the thermal decomposition of lanthanide ion fluoride precursors at high temperatures (>300 °C) in the presence of a coordinating ligand (oleic acid). UCNPs were synthesized at three different temperatures (310, 315 and 320 °C) and characterized in terms of morphological, structural and emission properties. In view of the intended biological applications, the surface of hydrophobic oleate-capped UCNPs was modified by a silica coating to achieve sufficient water dispersibility, through a modified Stöber process by a reverse micro-emulsion method. Monodisperse NaGdF4:Yb3+:Er3+ upconverting nanocrystals (~25 nm dia.) were obtained in cubic (at 310, 315 °C) and hexagonal phase (at 320 °C). The UCNPs in the hexagonal phase showed to be more suitable for application as a temperature sensor, because of its lower red-to-green emission ratio and higher thermal sensitivity. The emission spectra of NaGdF4:Yb3+:Er3+ (oleate- or silica-coated) UCNPs were measured at different temperatures in the vicinity of the physiological temperature range (20-70 °C) and presented suitable properties for application as a temperature sensor, such as excellent linearity (R2 >0.99) and sensitivity (>3 × 10−3 K−1). The surface of AuNSs were decorated with silica-coated UCNPs. The heating capacity of such nanocomposites (AuNSs@UCNPs) was verified by monitoring the Er3+ emission, enabling potential application as a hyperthermia agent controlled by the nanothermometer function. In a second part of this thesis, a multifunctional nanosystem was designed and applied as a dual sensor of ultraviolet (UV) light and temperature. Eu(tta)3 (tta-thenoyltrifluoroacetonate) complex was prepared in situ over the silica shell of NaGdF4:Yb3+:Er3+ UCNPs. A dual-mode nanothermometer-UV sensor was obtained from the combination of NIR to visible upconversion fluorescence signal of Er3+ ions and the UV-excited downshifted emission from the Eu(tta)3 complex. Measurements were performed near the physiological temperature range (2050 °C) revealing excellent linearity (R2 > 0.99) and relatively high thermal sensitivities (>1.5%·K−1). The Eu(tta)3 complex present in the silica shell was also demonstrated as a UV sensor because of the Eu3+ luminescence dependence on UV light exposure. The obtained material shows potential for application in light activated therapies, such as photodynamic therapy (PDT) and PTT, which typically require UV or blue light for excitation. The control of light dose released to the tissue is of great importance in these therapeutic procedures to avoid photodamage to the surroundings. The thermometer function is useful to guide such therapeutic processes (PDT and PTT) synergistically with the UV dosimeter. / Na área biomédica, existe uma crescente demanda por nanossistemas multifuncionais para realização de imageamento e terapia simultaneamente, visando um diagnóstico precoce e máximo benefício terapêutico. Nanopartículas para conversão ascendente de energia (UCNPs) vêm sendo propostas como a sonda biológica ideal devido às suas vantagens únicas relacionadas ao fenômeno de upconversion apresentado por materiais contendo íons lantanídeos, isto é, emissão no visível obtida sob excitação no infravermelho, tais como penetração profunda nos tecidos, uma baixa taxa de autofluorescência e um fotodano mínimo. Além disso, as propriedades luminescentes dos íons lantanídeos podem ser usadas para termometria por serem fortemente dependentes da temperatura. A termometria luminescente é uma técnica de não-contato e alta resolução que vem ganhando atenção na nanomedicina uma vez que a temperatura é um parâmetro fundamental para o funcionamento das células. Danos térmicos às células podem ser localmente fotoinduzidos pelo uso de nanoestruturas metálicas iluminadas em sua banda de ressonância plasmônica por causa da sua elevada absortividade. A primeira parte deste trabalho consiste no desenvolvimento de um sistema multifuncional baseado em nanocascas de ouro (AuNSs) decoradas com UCNPs podendo ser utilizadas para aumentar e medir a temperatura em escala nanométrica. Este sistema foi desenvolvido com a finalidade de uma eventual utilização como agente em terapia fototérmica (PTT), na qual a capacidade termométrica das UCNPs permitirá otimizar os benefícios terapêuticos. A síntese das UCNPs de NaGdF4 dopadas com os íons Yb3+ e Er3+ foi realizada via decomposição térmica de precursores de fluoreto de lantanídeo a altas temperaturas (> 300 °C) na presença de um ligante coordenante (o ácido oleico). As UCNPs foram sintetizadas em três diferentes temperaturas (310, 315 e 320 °C) e caracterizadas segundo suas propriedades morfológicas, estruturais e emissivas. Levando-se em conta as aplicações biológicas pretendidas, a superfície hidrofóbica das UCNPs recoberta por cadeias de oleato foi modificada utilizando um revestimento de sílica via um processo Stõber modificado por meio de um método de microemulsão reversa para obter uma dispersão suficiente em água. Nanocristais monodispersos de NaGdF4:Yb3+:Er3+ para conversão ascendente (~ 25 nm de diâmetro) foram obtidos nas fases cúbica (a 310, 315 °C) e hexagonal (a 320 °C). As UCNPs na fase hexagonal mostraram-se mais apropriadas como sensores de temperatura, devido a menor razão entre as emissões vermelho/verde e maior sensibilidade térmica. O espectro de emissão das UCNPs (recobertas por sílica ou por oleato) foi registrado a diferentes temperaturas na proximidade do intervalo fisiológico (20–70 °C) e apresentou propriedades adequadas para sua aplicação como sensor de temperatura, especialmente uma excelente linearidade (R2 > 0,99) e uma boa sensibilidade (>3 × 10−3 K−1). A superfície das AuNSs foi decorada com UCNPs recobertas por sílica. A capacidade de aquecimento das AuNSs@UCNPs foi verificada medindo-se a emissão do Er3+, a qual demonstra seu potencial como agente em hipertermia controlada pela utilização da função de nanotermômetro. A segunda parte deste projeto de tese foi dedicada ao desenvolvimento de um nanosistema multifuncional podendo ser utilizado como um sistema de dupla captura de luz UV e medida de temperatura. O complexo Eu(tta)3 (tta-tenoiltrifluoroacetonato) foi preparado in situ na casca de sílica das UCNPs de NaGdF4:Yb3+:Er3+. Um nanotermômetro de modo duplo foi obtido a partir do sinal de fluorescência gerado graças à conversão ascendente (infravermelho próximo → visível) pelos íons Er3+ juntamente à emissão por conversão descendente excitada no UV do complexo Eu(tta)3. As medidas foram realizadas próximo à faixa de temperatura fisiológica (20—50 °C) revelando uma excelente linearidade (R2 > 0,99) e uma sensibilidade térmica relativamente alta (≥1,5%·K−1). A utilidade do complexo de Eu(tta)3 presente na casca de sílica como sensor de luz UV foi demonstrado pela dependência da luminescência do íon Eu3+ sob a duração da exposição à luz UV. O material obtido apresenta potencial para aplicação em terapias ativadas pela luz, tais como a terapia fotodinâmica (PDT) e a PTT, as quais tipicamente requerem luz UV ou azul para excitação. O controle da dose de luz liberada para os tecidos tem grande importância nestes procedimentos terapêuticos para evitar o fotodano aos tecidos circundantes. A função de termômetro é útil para guiar tais processos (PDT e PTT) simultaneamente com o dosímetro de UV.

Quorum sensing in Gram-negative bacteria is best understood in the bioluminescent marine microorganism, <i>Vibrio fischeri</i>. In <i>V. fischeri</i>, the luminescence or <i>lux</i> genes are regulated in a cell density-dependent manner by the activator LuxR in the presence of an acylated homoserine lactone autoinducer molecule (3-oxo-hexanoyl homoserine lactone). LuxR, which binds to the <i>lux</i> operon promoter at position -42.5, is thought to function as an ambidextrous activator making multiple contacts with RNA polymerase (RNAP). The specific role of the <font face = "symbol">a</font>CTD of RNAP in LuxR-dependent transcriptional activation of the <i>lux</i> operon promoter has been investigated. The effect of seventy alanine substitution variants of the <font face = "symbol">a</font> subunit was determined <i>in vivo</i> by measuring the rate of transcription of the <i>lux</i> operon via luciferase assays in recombinant <i>Escherichia coli</i>. The mutant RNAPs from strains exhibiting at least two fold increased or decreased activity in comparison to the wild-type were further examined by <i>in vitro</i> assays. Since full-length LuxR has not been purified to date, an autoinducer-independent N-terminal truncated form of LuxR, LuxR<font face = "symbol">D</font>N, was used for <i>in vitro</i> studies. Single-round transcription assays were performed using reconstituted mutant RNAPs in the presence of LuxR<font face = "symbol">D</font>N, and fourteen residues in the <font face = "symbol">a</font>CTD were identified as having negative effects on the rate of transcription from the <i>lux</i> operon promoter. Five of these fourteen residues were also involved in the mechanism of both LuxR and LuxR<font face = "symbol">D</font>N-dependent activation <i>in vivo</i> and were chosen for further analysis by DNA mobility shift assays. Results from these assays indicate that while the wild-type <font face = "symbol">a</font>CTD is capable of interacting with the <i>lux</i> DNA fragment tested, all five of the variant forms of the <font face = "symbol">a</font>CTD tested appear to be deficient in their ability to recognize and bind the DNA. These findings suggest that <font face = "symbol">a</font>CTD-DNA interactions may play a role in LuxR-dependent transcriptional activation of the <i>lux</i> operon during quorum sensing. / Master of Science

The main theme of this dissertation is the study of two racemic compounds: a bimetallic complex, [(tpy)Ru(tppz)PtCl](PF₆)₃, and a trimetallic complex, [ClPt(tppz)Ru(tppz)PtCl](PF₆)₄, in solution and in the solid state, where tpy is 2,2':6',2''-terpyridine and tppz is 2,3,5,6-tetrakis(2-pyridyl)pyrazine. These two supramolecular assemblies display remarkably different stereochemistry, electrochemistry and photochemistry. The chapters in this document deal with a multidisciplinary project that is fundamental to the design and synthesis of similar entities with potential applications as antitumor agents. Chapter 1 gives an overview on the metal polyazine supramolecules. More specifically, the section is focused on the tridentate ruthenium and platinum metallic supramolecular assemblies with emphasis on their functionality and the methods used to study such systems. Chapter 2 describes the design and syntheses of the title complexes and their analogs using a building block strategy. The details of the experimental methods are included in this section. Chapter 3 presents the identification of the title complexes in solution and in the solid state by means of single crystal crystallography, mass spectrometry including FAB-MS and ESI-MS, and multiple NMR techniques including 1D ¹H-NMR, ¹⁹⁵Pt-NMR and 2D COSY, NOESY and ¹⁹⁵Pt-¹H HMQC, as well as dynamic ¹H-NMR at variable temperatures. The bi- and tri-metallic complexes are crystallized in the chiral space group of C2/c and P21/c as racemic compounds. The interconversion of the three steroisomers, M-M, P-P and M-P of trimetallic complexes are detected in the NMR timescale. The assignments of the atypical NMR resonance of the bi- and tri-metallic complexes are supported with the help of multidimensional NMR techniques and NMR spectroscopy of known systems. The process of assigning the NMR spectra is accomplished step by step with complexities presented by ring current effects. The 1D-fiber, 2D-plate and 3D-flowerlike topography of the trimetallic complex of [ClPt(tppz)Ru(tppz)PtCl](PF₆)₄ was illustrated by SEM. Chapter 4 demonstrates the electrochemical and photochemical differences between the title complexes and a comparison to known systems. Electrochemically, the Ru^II,Pt^II bimetallic and trimetallic complexes display Ru^II/III oxidations at 1.63 and 1.83 V and ligand-based reduction at -0.16 and -0.03 V versus Ag/AgCl, respectively. Spectroscopically, the Ru(dπ)⟶ tppz(π*) MLCT transitions are red-shifted relative to the monometallic synthons ([(tpy)Ru(tppz)](PF₆)₂, λ_max^abs = 472 nm and [Ru(tppz)₂](PF₆)₂, λ_max^abs = 478 nm) occurring in the visible region, centered at 530 and 538 nm in CH₃CN for [(tpy)Ru(tppz)PtCl](PF₆)₃ and [ClPt(tppz)Ru(tppz)PtCl](PF₆)₄, respectively, consistent with the bridging coordination of the tppz ligand. [ClPt(tppz)Ru(tppz)PtCl](PF₆)₄ displays an intense emission (Φ^em = 5.4×10₄) from the Ru(dπ)⟶ tppz(π*) ³MLCT state at RT with λ_max^em = 754 nm and lifetime ofτ„ = 80 ns in CH₃CN solution. The trimetallic complex, [ClPt(tppz)Ru(tppz)PtCl](PF₆)₄, exhibits a strong emission property in the solid state with λ_max^em = 764 nm, which was also studied by confocal laser induced emission scanning microscopy. By contrast, a barely detectable emission was observed for the bimetallic complex, [(tpy)Ru(tppz)PtCl](PF₆)₃. The redox and luminescence differences between bi- and tri-metallic complexes is the consequence of the nature of these supramolecular assemblies. All together the data suggest strong PtPt interactions in solution providing for assembly of these molecules into dimers or larger assemblies. Chapter 5 reports the applications of these complexes as bioactive species interacting with DNA. The prelimary data show the title complexes bind to DNA producing larger changes in DNA migration during gel electrophoreses than does the well-established anticancer drug, cisplatin. Preliminary study indicates trimetallic complex [ClPt(tppz)Ru(tppz)PtCl](PF₆)₄ can photochemically condenses DNA. This data could provide a form for development of a new class of photodynamic therapy agents in cancer treatment. Chapter 6 concludes with summaries of current research and perspective for further work. / Ph. D.

La synthèse et la caractérisation de nanoparticules de polymère dopées d’un complexe luminescent et de nanoparticules d’argent ont été réalisées. La polymérisation en mini-émulsion a permis d’obtenir des nanoparticules de polystyrène dopées d’un complexe luminescent. La concentration de complexe d’europium maximale pouvant être atteinte, sans qu’il y ait déstabilisation de l’émulsion, est de 2% (m/m). Il est également possible de préparer des nanoparticules de polymère contenant le complexe luminescent, ainsi que des nanoparticules métalliques. Pour ce faire, le complexe et les nanoparticules métalliques doivent être dispersés dans le monomère de départ. Il est donc nécessaire de modifier la surface des nanoparticules métalliques afin qu’il y ait une bonne affinité entre les nanoparticules métalliques et le polymère. Il est intéressant de confiner les nanoparticules métalliques dans la même particule de polymère que le luminophore afin d’observer leur impact sur la luminescence. Le rehaussement ou l’exaltation de la luminescence au voisinage de nanoparticules métalliques est un phénomène bien connu. Lorsqu’une nanoparticule métallique est excitée par une onde électromagnétique qui correspond à la fréquence de résonnance du nuage électronique de la particule, une augmentation du champ électrique est engendrée à proximité de la particule et a pour effet de rehausser la luminescence des luminophores à proximité. Les propriétés optiques des nanoparticules hybrides obtenues (polystyrène/complexe luminescent/argent) montrent, qu’effectivement, en présence d’argent, une augmentation de l’intensité lumineuse peut être observée.

Polypyridyl transition metal complexes containing ruthenium, rhodium and iridium centers are mainly studied due to their light absorbing and emitting properties. Lanthanide oxides such as europium oxide absorb light as well and exhibit strong luminescence and long lifetimes. The optical properties of these materials were significant especially in solar energy utilization schemes and optical applications. Energy transfer across a surface is important in several applications including phosphors and biomedical applications. Excited states of metal complexes with a carboxylate-containing ligand such as deeb = diethyl-2,2'-bipyridine-4,4'-dicarboxylate were studied on nanoparticle surfaces. In this work, [Rh(deeb)2Cl2](PF6), [Ir(deeb)2Cl2](PF6) and [Ir(deeb)2(dpp)](PF6)3 were synthesized using the building block approach. The metal complexes were characterized using 1H NMR spectroscopy, mass spectrometry, electronic absorption spectroscopy and electrochemistry. The 1H NMR spectra of the complexes were consistent with those of their ruthenium analogs. Mass spectra contain fragmentation patterns of the (M-PF6)+ molecular ion for [Rh(deeb)2Cl2](PF6) and [Ir(deeb)2Cl2](PF6), and (M-3PF6)3+ molecular ions for [Ir(deeb)2(dpp)](PF6)3. The electronic absorption spectrum of [Rh(deeb)2Cl2](PF6) shows a maximum at 328 nm, which is assigned as 1π→π*transition. The electronic absorption spectrum of [Ir(deeb)2Cl2](PF6) shows maxima at 308 nm and 402 nm, which are assigned as 1π→π* and metal-to-ligand charge transfer transitions, respectively. The [Ir(deeb)2(dpp)](PF6)3 complex exhibits peaks due to 1π→π* transitions at 322 nm and 334 nm. [Rh(deeb)2Cl2](PF6) has emission maxima from the 3LF state at 680 nm and 704 nm for the solid and glassy solutions at 77 K, respectively. [Ir(deeb)2Cl2](PF6) has emission maxima from the 3MLCT state at 538 nm in acetonitrile and 567 nm in the solid state at room temperature, with lifetimes of 1.71 μs and 0.35 μs, respectively. [Ir(deeb)2Cl2](PF6) has an unusually higher quantum yield than analogous compounds. [Ir(deeb)2(dpp)](PF6)3 has emission maxima from the 3IL state at 540 nm in acetonitrile and 599 nm in the solid state at room temperature, with lifetimes of 1.23 μs and 0.14 μs, respectively. Cyclic voltammetry of [Ir(deeb)2Cl2](PF6) and [Ir(deeb)2(dpp)](PF6)3 yield reversible and quasi-reversible couples corresponding to deeb ligand and Ir3+/+reductions, respectively. Attachment of the complexes were conducted by equilibration of complex solutions in acetonitrile with europium oxide nanoparticles. Europium oxide nanoparticles, which were synthesized by gas-phase condensation, have 11-nm diameters and exhibit sharp f-based luminescence in the visible and near IR regions. EDX, TEM, IR and reflectance spectroscopy measurements indicate substantial coating through various modes of attachment of the nanoparticle surface by the metal complexes while retaining the excited state properties of the metal complexes. Surface adsorption studies indicate monolayer coverage of the nanoparticle surface by the metal complexes, consistent with limiting surface coverages of previously reported analogous systems. Eu2O3 nanoparticles modified with [Rh(deeb)2Cl2]+ exhibit minimal to no energy transfer from emission spectra, and a reduction in the lifetime at 77K could be due to the rhodium complex preventing the excitation of Eu3+. Upon attachment of the Ir complexes [Ir(deeb)2Cl2]+ and [Ir(deeb)2(dpp)]3+ on as-prepared nanoparticles, Eu3+ luminescence was observed for nanoparticles modified with iridium complexes at room temperature, which could be due to energy transfer among other possibilities. Efficiencies of 68% and 50%, and energy transfer rate constants of 1.1 x 10-5 and 1.0 x 10-5 were calculated from lifetime data for [Ir(deeb)2Cl2]+ and [Ir(deeb)2(dpp)]3+ on Eu2O3 nanoparticles, respectively. Since iridium complexes are used as components of light-emitting diodes, europium oxide nanoparticles modified with iridium complexes have potential in optical applications which make studies of these compounds interesting. / Master of Science

The mechanism of gene regulation used by Gram-negative bacteria during quorum sensing is well understood in the bioluminescent marine bacterium Vibrio fischeri. The cell-density dependent activation of the luminescence (lux) genes of V. fischeri relies on the formation of a complex between the autoinducer molecule, N-(3-oxohexanoyl) homoserine lactone, and the autoinducer-dependent transcriptional activator LuxR. LuxR, a 250 amino acid polypeptide, binds to a site known as the lux box centered at position -42.5 relative to the luxI transcriptional start site. During transcriptional activation of the lux operon, LuxR is thought to function as an ambidextrous activator capable of making multiple contacts with RNA polymerase (RNAP). The specific role of region 4 of the Escherichia coli sigma 70 subunit of RNAP in LuxR-dependent transcriptional activation of the luxI promoter has been investigated. Rich in basic amino acids, this conserved portion of sigma 70 is likely to be surface-exposed and available to interact with transcription factors bound near the -35 element. The effect of 16 single and 2 triple alanine substitution variants of sigma 70 between amino acid residues 590 and 613, was determined in vivo by measuring the rate of transcription from a luxI-lacZ translational fusion via b-galactosidase assays in recombinant E. coli. In vitro work was performed with LuxRDN, the autoinducer-independent C-terminal domain (amino acids 157 to 250) of LuxR because purified, full length LuxR is unavailable. Single-round transcription assays were performed in the presence of LuxRDN and 19 variant RNAPs, one of which contained a C-terminally truncated sigma 70 subunit devoid of region 4. Results indicate that region 4 is essential for LuxRDN-dependent luxI transcription with two specific amino acid residues, E591 and K597, having negative effects on the rate of LuxRDN-dependent luxI transcription in vivo and in vitro. None of the residues tested were identified as having any effect on LuxR-dependent luxI transcription in vivo. These findings suggest that region 4.2 is most likely to be in close proximity to LuxR when bound to the luxI promoter. However, unlike the situation found for other ambidextrous activators, no single residue within region 4.2 of sigma 70 may be critical by itself for LuxR-dependent during transcriptional activation. / Master of Science