Dans ce travail de thèse j’ai étudié la structure et la réactivité des couches minces des phthalocyanine de lutétium déposées sur des surfaces métalliques. La connaissance de la structure des couches minces épitaxées des matériaux organiques est importante pour la conception des dispositifs d’électronique organique. En effet la mobilité des porteurs de charge est très influencée par l’organisation moléculaire et l’ordre de la couche. La deuxième partie de ce travail concerne la réactivité des couches minces de ces molécules avec les gaz atmosphériques, ce qui est essentiel à la stabilité des dispositifs.Les couches minces ont étés préparées par évaporation thermique sous ultra vide et ont étés analysées par Microscopie a scansion de tunnel (STM), diffraction des rayons x (XRD), photoémission x (XPS) et Spectroscopie d’absorption x (NEXAFS). La structure des couches minces des LuPc2 déposées sur Au(111) a été trouvée. Les molécules adoptent une structure β et ressentent de l’effet modèle du substrat, comme prédit par les relations épitaxies. La morphologie de surface a été également trouvée à l’échelle moléculaire, y compris l’empillement et l’orientation des domaines.La faible réactivité de ces couches minces avec des gaz atmosphérique, en particulier oxygène et eau, a été prouvée. Le site d’absorption des molécules des gaz a été localisé non pas sur l’ion central mais plutôt sur le macrocycle organique. Il a été démontré aussi que ces molécules sont plus réactives vers l’oxygène moléculaire que vers l’eau. / In this thesis work I studied the structure and reactivity of Lutetium bis-phthalocyanine (LuPc2) thin films deposited on metallic surfaces. Knowing the structure of epitaxial organic thin films is important to design devices based on organic electronics, because carrier mobility, critically depends on the molecular configuration and thin film ordering. The second part of the work deals with the reactivity of molecular thin films towards atmospheric gases which is crucial for lifetime of the device. We chose LuPc2 because, due to the double decker molecular geometry they should present a different reactivity respect to single decker phthalocyanine, which are widely used in devices.The thin films were prepared by thermal evaporation under ultra-high vacuum conditions and analysed by means of Scanning Tunnelling Microscopy (STM) and X-ray Diffraction (XRD), X-ray Photoemission Spectroscopy (XPS) and Near Edge X-ray Absorption Fine Structure Spectroscopy (NEXAFS).We resolved the structure of a LuPc2 thin film deposited on Au(111), showing that the molecules adopt a β structure and demonstrated the templating effect of the substrate via the epitaxial relations with the overlayer. We then present the surface morphology at the molecular scale, including stacking and domain orientations.We tested the reactivity of these thin films towards atmospheric gases, in particular oxygen and water, showing a low reactivity and managing to demonstrate the adsorption sites, which are not the central cation, but rather on the macrocycle. We showed how oxygen is a greater threat to the film stability than water.

La mise en évidence d’effets de polarisation d’échange (“exchange bias”, EB) ouvre de nouvelles perspectives dans le domaine émergeant de la spintronique organique. Dans une première partie de la thèse, on étudie l’EB des systèmes Co/MPc et Py/MPc (M=Mn, Co, Fe, Zn) par magnétométrie. Pour tous ces systèmes, l’EB est observé avec des températures de blocage de 100K environ. Ces études sont complétées par des mesures de résonance ferromagnétique confirmant les valeurs du champ de polarisation. Dans une troisième partie, on étudie les propriétés magnétiques des tricouches Co/Pc/Co. Les cycles d’hystérèse présentent des marches indiquant un renversement séquentiel des couches de cobalt. A basse température, on observe de l’anisotropie unidirectionnelle pour les deux couches mais leurs champs de polarisation diffèrent. / Observation of exchange bias (EB) phenomenon by using molecular materials as a pinninglayer open the horizon for tremendous perspective in the field of organic spintronics. Thefirst part of the thesis is devoted to the study of EB of Co/MPc and Py/MPc (M=Mn, Co, Fe,Zn) by static magnetometry. The existence of EB is evidenced in all Pc molecules with block-ing temperature around 100K. The second part is devoted to the study of EB by dynamicFMR measurements. The values of EB measured by this method are compatible with staticmagnetometry measurements. The third part is devoted to study magnetic properties of thetrilayer Co/Pc/Co systems. Hysteresis loops exhibit a stepped shape indicative of successivereversal of each layer. Low temperature loops show that both Co layers experience unidi-rectional anisotropy after field cooling, with differing bias fields.

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Two of the main technological challenges of the century are the production of clean energy, on the one hand, and the development of new materials for electronic and spintronic applications that could increase the speed and the storage capacity of regular electronic devices, on the other hand. Organic materials, including fullerenes, organic polymers and organic molecules with metal centres are promising candidates for low-cost, flexible and clean technologies that can address these challenges. A thorough description of the electronic properties of such materials is, therefore, crucial. The interaction of electromagnetic radiation with the molecule can provide the needed insight into the electronic and vibrational levels and on possible chemical interactions. In order to explain and interpret experimentally measured spectra, a good theoretical description of the particular spectroscopy is necessary. Within density functional theory (DFT), the current thesis discusses the theoretical tools used to describe the spectroscopic properties of molecules with emphasis on two classes of organic materials for photovoltaics, molecular electronics and spintronics. Specifically, the stability of the fullerene derivative PC60BM is investigated in connection with its use as an electron acceptor in organic solar cells and the valence band electronic structure of several transition metal phthalocyanines is studied for their possible application in electronics and spintronics. The spectroscopies discussed in the current work are: the photoelectron spectroscopy of the valence band, X-ray photoelectron spectroscopy of the core levels, near-edge X-ray absorption fine structure, Infrared and Raman vibrational spectroscopies

There is a need to develop techniques for conversion of carbon dioxide to other useful products such as methanol, formaldehyde, formic acid, formate, methane, and hydrocarbons. Carbon dioxide can be converted into these products using different methods such as photochemical, electrochemical, thermochemical and hydrogenation by bacteria. Formate is of interest due to its wide industrial applications which include it’s use in direct liquid fuel cells, as an additive in pyrolysis vapors, a precursor for biological fuels, and it is a key intermediate in methanogenesis breaking down complex organic compounds. In this work, conversion of carbon dioxide to formate was accomplished photochemically. The concentration of formate obtained was quantified using ion chromatography. The yield of formate, based on the amount of carbon dioxide in solution, was 1.54%, while the quantum yield was near 2.0%. Detailed studies of the photoreduction process showed that the amount of sensitizer, light intensity and pH affect the amount of formate generated.

O laser é uma fonte de radiação não ionizante altamente concentrada que em contato com diferentes tecidos resulta, de acordo com o tipo de laser, em efeitos térmicos, fotoquímicos e não lineares. Atualmente, o laser tem sido rotineiramente empregado em diversas áreas da ciência, assim como na Medicina e Odontologia. Os tratamentos com utilização de radiação a laser de baixa intensidade na odontologia são de grande interesse para as áreas de cirurgia buco-maxilo-facial e implantodontia sendo usado para a estimulação do processo de osteogênese. Um novo tratamento promissor envolve o processo fotodinâmico e emprega a combinação de dois agentes terapêuticos: um fármaco fotossensível e uma baixa dosagem de luz visível que combinados em presença de oxigênio provocam a bioestimulação celular. É um método eficiente, não-invasivo. Avaliar a utilização do fármaco fotossensível derivado das ftalocianinas com a ftalocianina de cloro-alumínio para o uso no tratamento para estimulação da osteogênese é o objetivo deste trabalho, será avaliado também a potencialidade terapêutica do processo. Na tentativa de se obter melhores resultados com esses fármacos, tem surgido nos últimos anos um interesse muito grande no desenvolvimento de formulações nanoestruturadas, dentro de uma linha altamente emergente de pesquisa a Nanobiotecnologia. Neste contexto, surge dentre os vários sistemas de veiculação disponíveis, as nanoemulsões, que permitem solubilizar fármacos hidrofóbicos em água, mantendo suas características físico-químicas. / The laser is a source of non ionizing radiation highly concentrated and coherent that in contact with different tissues induce thermal, photochemical and non-linear effects according to the type of the laser. Currently, the laser has been used routinely in many areas of science, as well as in medicine and dentistry. The treatments using laser radiation of low intensity in dentistry are of great interest specially in the areas of surgery bucco-maxillo-facial and dental implants and its being used to stimulate the process of osteogenesis. A promising new treatment in dentistry area involves the photodynamic process and employs a combination of two therapeutic agents: a photosensitizers drug and a low dose of visible light that combined in the presence of oxygen could induce cellular biostimulation. It is an efficient non-invasive method. Evaluate the use of the drug derived system to administrate photosensitizers as phthalocyanine derivatives chlorine-aluminum specifically for the use in treatment and stimulation of the osteogenesis is the main objective of this work. It will be also evaluated the therapeutic potential of the process. In an attempt to obtain better biocompatibility of these drugs it has developed in recent years an additional interest in the development of nanostructured formulations, focused in a highly emerging line of research the Nanobiotechnology. The nanoemulsion formulation was selected to this work. It was showed that the hydrophobic drugs choose for this work maintaining its photophysical and chemical characteristics in this medium applicable to biological tissue.

A Terapia Fotodinâmica (TFD) é uma modalidade terapêutica inovadora para o tratamento de tumores cutâneos. As ftalocianinas têm sido utilizadas como fotossensibilizantes sistêmicos devido à sua alta afinidade ao tecido tumoral e seu efeito acentuado quando irradiadas com luz. No entanto, a lipossolubilidade e o baixo coeficiente de partilha óleo/água dessas substâncias dificultam sua aplicação tópica, levando ao desenvolvimento de derivados carregados, como a zinco ftalocianina tetrassulfonada (ZnPcS4) na tentativa de aumentar sua solubilidade em água, bem como melhorar sua captação pelas células tumorais. Entretanto, moléculas carregadas têm dificuldades em atravessar o estrato córneo (EC), a principal barreira da pele. Como a iontoforese é uma técnica não-invasiva capaz de aumentar e controlar a penetração de moléculas carregadas na pele, ela parece ser uma alternativa para aumentar a penetração cutânea da ZnPcS4 nas camadas da pele onde os tumores estão presentes. Dessa forma, foram realizados experimentos in vitro de iontoforese de um gel hidrofílico da ZnPcS4 aplicado topicamente na presença e ausência de NaCl. Estudos de iontoforese in vivo também foram realizados, empregando ratos Wistar como modelo animal, bem como experimentos em cultura de células tumorais para avaliar a citotoxicidade do fármaco em estudo. O método analítico para quantificação do fármaco na pele foi validado quanto à linearidade, precisão, exatidão, sensibilidade e seletividade. A iontoforese catódica promoveu um aumento significativo da retenção da ZnPcS4 tanto no EC como na epiderme viável nos experimentos realizados na presença e ausência de NaCl em relação à aplicação passiva da formulação e de iontoforese anódica, sendo que ocorreu um aumento da quantidade do fármaco retido nas diferentes camadas da pele quando o sal foi retirado da formulação. Os estudos in vivo com a formulação também mostraram que a corrente elétrica aumentou a penetração do fármaco para as camadas mais profundas da pele em relação aos experimentos passivos de permeação, o que foi evidenciado pela intensidade de fluorescência do fármaco visualizada por microscopia confocal e pela quantidade de fármaco retido nas diferentes camadas da pele. Resultados em cultura de células tumorais A431 sugerem que a concentração de fármaco que chega à epiderme viável após experimentos de iontoforese catódica é capaz de matar mais de 90% dessas células tumorais quando a dose de irradiação de 5 J/cm2 é aplicada. Além disso, quando a corrente elétrica é aplicada em cultura celular, não foi observado nenhum aumento significativo da citotoxicidade da ZnPcS4, demonstrando que a aplicação de corrente elétrica não fez com que a entrada do fármaco para o interior das células tumorais aumentasse. Não restam dúvidas, no entanto, que a corrente elétrica aumentou a penetração do fármaco nas camadas profundas da pele, além de levar a uma distribuição homogênea da ZnPcS4 nessas camadas após 15 minutos de aplicação. / Photodynamic therapy (PDT) is an innovative therapeutic modality for the treatment of cutaneous tumors. The phthalocyanines have been used as systemic photosensitizing agents due to its high affinity to tumor tissues and its accentuated effect when irradiated with light. However, the lipophilicity and the low partition coefficient oil/water of these substances difficult its topical application, leading to the development of charged derivatives, such as the zinc phthalocyanine tetrasulfonated (ZnPcS4) in an attempt to increase the water solubility, as well as improve the drug uptake by tumor cells. However, charged molecules have difficulties to cross the stratum corneum (SC), the main barrier of the skin. As iontophoresis is a noninvasive technique able to improve and control the penetration of charged molecules through the skin, it seems to be an alternative for enhancing ZnPcS4 penetration into the deep layers of the skin, where cutaneous tumors reside. This way, in vitro iontophoresis experiments of a hydrophilic gel containing ZnPcS4 applied topically in the presence and absence of NaCl were performed. In vivo iontophoresis studies were also carried out employing Wistar rats as animal model, as well as experiments in culture of tumour cells to evaluate the cytotoxicity of the drug. The analytical method for the quantification of the drug in the skin was validated considering the parameters of linearity, precision, accuracy, sensitivity and selectivity. The cathodal iontophoresis promoted a significant increase in retention of ZnPcS4 in both SC and viable epidermis in the experiments conducted in the presence and absence of NaCl in relation to the formulation applied passively or by anodal iontophoresis. Therefore, there was an increase in the amount of the drug retained in different layers of the skin when salt was removed from the formulation in the cathodal iontophoresis. In vivo studies also demonstrated that the electrical current increased penetration of the drug to the deeper layers of the skin in relation to passive experiments, evidenced by the fluorescence intensity of the drug showed by confocal microscopy and by the amount of drug retained in the different layers of the skin. Results with A431 tumor cells suggest that the concentration of the drug that reaches the viable epidermis after cathodal iontophoresis is able to kill more than 90% of these tumor cells when the radiation dose of 5 J/cm² was applied. In addition, when the electric current was applied to the cells, it was not observed any significant increase of cytotoxicity, demonstrating that the electric current application did not increased the uptake of the ZnPcS4 by the tumor cells. There are no doubts, however, that the electric current increased the ZnPcS4 penetration to the deep layers of the skin and lead to a homogeneous distribution of ZnPcS4 in these layers after 15 minutes of application.

Úlceras são alterações que ocorrem na integridade da pele como consequência de lesões diversas, constituindo a dificuldade de sua cura um grave problema de saúde pública. A fototerapia com laser de baixa intensidade (LLLT), através de seus efeitos biomoduladores, vem sendo apontada como uma técnica prática, rápida e eficaz para esses casos. Entretanto, aplicações de LLLT podem, em alguns casos, estimular a proliferação de microrganismos patogênicos presentes na lesão, resultando numa piora da infecção e maior retardo no processo de reparo. Nesses casos, o uso de quimioterapia fotodinâmica antimicrobiana (PACT) pode ser uma alternativa. O presente estudo testou a eficácia da PACT com Ftalocianina Cloro-Alumínio (FC-ClAl) e da LLLT na inativação de microrganismos, com uma dose energética adequada para não prejudicar o processo de cicatrização. Em biofilmes de P. aeruginosa e S. aureus previamente cultivados por um período de 24 h em microplacas de 24 e 96 poços, realizou-se etapa única de aplicação da fototerapia LLLT e PACT com 4 diferentes formulações para inativação de microrganismos: formulação vazia (ausência de fármaco fotossensível FV), formulação catiônica vazia (com alteração em sua polaridade FCV), formulação aniônica com fármaco fotossensível (apenas Ftalocianina Cloro-alumínio FC-ClAl FAPc), formulação catiônica com fármaco fotossensível (FC-ClAl + formulação com polaridade alterada FCPc). Foram feitas análises quantitativas através da contagem de células viáveis e medidas de absorbância em leitora de ELISA com sal tetrazólio, 3-(4,5-dimethylthiazol-2-yl)-2,5-difenil brometo de tetrazólio (MTT), associado. Os dados obtidos foram comparados através de análise de variância (ANOVA) com nível de confiança de 95%. Os resultados obtidos permitiram concluir que a PACT com FC-ClAl sozinha (FAPc) não apresenta ação bactericida satisfatória sobre a P. aeruginosa e a S. aureus, mostrando resultados estimulatórios a esses microrganismos quando comparada às outras 3 formulações utilizadas. A ação antimicrobiana só foi observada ao se ter a associação da PACT Ftalocianina cloro-alumínio com a formulação catiônica (FCPc), a qual mostrou intensa interação com os biofilmes microbianos, principalmente com a S. aureus, mesmo na ausência de Ftalocianina (FCV). / Ulcers are changes on the skin integrity as a consequence of several lesions, and its cure represents a serious public health problem. Phototherapy based on low level laser therapy (LLLT), through its biomodulatory effects, has been pointed as a fast, practical and effective therapy for these cases. However, LLLT applications may, in some cases, stimulate pathogenic microorganisms proliferation present in the lesion, resulting in a worst infection and longer delay on the healing process. For such cases the use of Photodynamic Antimicrobial Chemotherapy (PACT) can be an alternative. The present study tested the PACT effectiveness with a phthalocyanine-derived photosensitizer and LLLT on microorganism inactivation, with an adequate energy dose in order to not damage all the healing process. On P. aeruginosa and S. aureus mature biofilms, previously cultivated for a period of 24 h in 24 and 96 wells-plate, a single application of phototherapy based on LLLT and PACT to inactivate bacteria was performed, with four different formulations: blank formulation (FV - no photosensitive drug), cationic empty formulation (FCV - formulation with an inverted polarity), formulation with anionic photosensitive drug (FAPc - only Chloro-aluminum Phthalocyanine) and cationic formulation with photosensitive drug (FCPc - Chloro-aluminum Phthalocyanine associated with an inverted polarity formulation). Quantitative analyses were performed through the counting of colony forming units (CFU) and the absorbance analysis with MTT associated. The data were compared through variance analysis test (ANOVA), with a confidence level of 95%. The results showed that PACT with Chloro-aluminum Phthalocyanine itself does not present satisfactory bactericidal effect against P. aeruginosa and S. aureus. This photosensitizer (FAPc) presented a microorganism stimulatory action when compared with the other three formulations used. The bactericidal effect was seen only with the PACT with cationic formulation association, which demonstrated an intense interaction with microbial biofilms, especially with S. aureus, even in the absence of Phthalocyanine (FCV).

Core- and Valence Photoelectron Spectroscopy (PES), X-ray- and Ultraviolet-Visible Absorption Spectroscopy (XAS and UV-Vis), Scanning Tunneling Microscopy (STM) and Density Functional Theory (DFT) calculations are used to study the electronic and geometrical structure of a class of macro-cyclic molecules, Phthalocyanines (Pc), on surfaces. These molecules are widely studied due to their application in many different fields. Multilayer and monolayer coverages of Iron Phthalocyanine (FePc) and metal-free Phthalocyanine (H2Pc) deposited on different surfaces are investigated in order to get insight in the electronic and geometrical structure of the obtained overlayers, of crucial importance for the understanding of the film functionality. Sublimation of molecular thick films on Si(100) and on conducting glass results in films with molecules mainly oriented with their molecular plane orthogonal to the surface. Ex-situ deposited H2Pc films on conductive glass show different molecular orientation and morphology with respect to the vacuum sublimated films. We study the monolayer adsorption structure of FePc and H2Pc and compare our results with other Pc’s adsorbed on graphite. We find that the molecular unit cell and the superstructure is characteristic for each Pc adsorbed on graphite, even if the geometrical size of the compared molecules is the same. The PE- and XA- spectra of FePc on graphite are essentially identical for the mono- and multilayer preparations, evidencing weak intermolecular and molecular-substrate interactions of van der Waals nature. Furthermore, we characterize Pc’s on InSb (001)-c(8x2). The substrate In rows are observed to be the adsorption site for Pc’s. We find that the growth of the two-dimensional islands of FePc is prolonged in the [-110] direction, in contrast to ZnPc adsorbed on the same substrate at room temperature. We interpret this result as an indication that the adsorption is controlled by the substrate corrugation observed at 70 K.

This thesis has involved an attempt to form a germanium-carbon bond through the reaction of germanium compounds with dilithium phthalocyanine, metal-free phthalocyanine, methyl magnesium iodide, phenyl magnesium bromide, and 1,3-diiminoisoindoline. The reaction products were examined in several ways to help establish their identity. Chemical and spectroscopic analyses were used to determine the nature of the two trans groups in the phthalocyanine compounds. Infrared spectra implied the formation of the germanium-carbon bond.Ball State UniversityMuncie, IN 47306