The continuously increasing demand for innovation in the miniaturization of microelectronics has driven the need for ever more precise fabrication strategies for device packaging, especially for printed circuit boards (PCBs). Subtractive copper etching is a fundamental step in the fabrication process, requiring very precise control of etch rate and etch factor. Changes in the etching chemical equilibrium have significant effects on etching behavior, and CuCl2 / HCl etching baths are typically monitored with several parameters including oxidation-reduction potential, conductivity, and specific gravity. However, the etch rate and etch factor can be difficult to control even under strict engineering controls of those monitoring parameters. The mechanism of acidic cupric chloride etching, regeneration and recovery is complex, and the current monitoring strategies can have difficulty controlling the interlocking chemical equilibria. A complimentary tool, thin-film UV-Vis spectroscopy, can be utilized to improve the current monitoring strategies, as UV-Vis is capable of identifying and predicting etching behavior that the current standard methodologies have difficulty predicting. Furthermore, as a chemically-sensitive probe, UV-Vis can investigate the complex changes to the chemical equilibrium and speciation of the etch bath, and can contribute overall to significant improvements in the control of the copper etching system in order to meet the demands of next-level design strategies.

As ferroporfirinas sintéticas são sistemas complexos que vêm sendo amplamente estudadas. A dificuldade em obter informações estruturais, reações químicas e ligantes do íon central vêm estimulando o estudo pormenorizado desses sistemas. Nestes trabalho é apresentada a caracterização da série de FeP fluorosubstituídas, que compreende as mono-, di-, tri e tetra- fluorofenilporfirina, denominadas FeTF5PP, FeTF10PP, FeTF15PP e FeTF20PP, respectivamente. Essas FeP são estudadas em função dos solventes diclorometano (DCM), metanol (MeOH) e das várias misturas em volume desses dois. As técnicas espectroscópicas de Absorção Eletrônica na região do Ultravioleta ao Visível (UV-Vis) e Ressonância Paramagnética Eletrônica (EPR) são as duas ferramentas de estudos escolhidas para caracterizar esses sistemas. Partindo-se de uma solução de FeP dissolvida em DCM, foram adicionadas alíquotas de Me0H até completar-se 50% em volume desses dois solventes. Através dessa titulação, observamos a formação de diferentes espécies como conseqüência da coordenação do Me0H à FeP. Notamos também, as modificações estruturais reveladas principalmente pelo EPR, ocasionadas pelos diferentes números de substituintes fluorofenis. Essa técnica espectroscópica revelou ainda a existência de interações que não foram anteriormente observadas. Para a FeTFloPP foi verificada a interação super hiperfina entre o Fe e o ligante CF além da interação super hiperfina entre o Fe e os nitrogênios do anel porfirínico. Para a FeTF20PP foi verificada apenas a interação super hipeOna entre o Fe e o ligante Cl-. As demais FeP não apresentaram essas interações / Synthetic iron porphyrins are complex systems that have been largely studied. Difficulties to obtain structural information, chemical reactions and ligands of the central ions have been a subject to investigate details of these systems. In this work, a systematic characterization of one series of fluorophenyl iron porphyrins is presented. Mono-, di-, tri- and tetrafluorophenyl substituents called FeTF5PP, FeTF10PP, FeTF15PP, and FeTF20PP, respectively, are included in this series. Iron porphyrins were studied as a function of dichloromethane, methanol solvents and several of their mixture in volume. These systems were characterized by Ultraviolet- Visible and Electron Paramagnetic Resonance Spectroscopes. From iron porphyrin solutions, dissolved in dichloromethane, aliquots of methanol were added up to 50% in volume of these two solvents. With this titration, we found different species because of the methanol coordination to the iron porphyrins. We also observed the structures modification revealed by the EPR spectroscopy, as a function of different numbers of fluorophenyl substituents. The EPR spectroscopy also revealed the existence of the super hyperfine interactions not observed before. It was found for FeTFloPP between the central ion and the axial ligand chlorine Cl - ion, besides the hyperfine interaction between iron and the nitrogen of the pyrrole ring. For FeTF20PP only the super hyperfine interaction, Fe-C1 was found. These interactions were not observed for the other iron porphyrins

Nesta tese, apresentamos estudos experimentais e teóricos realizados com o Ácido orto-Aminobenzóico (o-Abz) e seus derivados 2-amino-benzamida (o-Abz-NH2), 2-amino-metil-benzamida (o-Abz-NH(CH3)) e 2-amino -dimetilbenzamida (o-Abz-N(CH3)2). Foram feitas medidas de absorção óptica, fluorescência estática e resolvida no tempo e anisotropia de fluorescência em solventes com diferentes graus de polaridade e diferentes capacidades de doar e aceitar prótons. Os resultados experimentais foram comparados aos resultados de simulações computacionais que simularam o sistema solventesoluto. Restrições impostas pelas limitações computacionais impedem cálculos totalmente quânticos via métodos ab-initio, porém uma metodologia que tem apresentado resultados satisfatórios é o método híbrido que envolve a mecânica quântica associada à mecânica molecular (QM/MM). No presente trabalho, foram combinados cálculos quânticos ab-initio e semi-empíricos na otimização de geometrias de moléculas isoladas e no cálculo de energias de transições respectivamente. Foram simulados os sistemas soluto+solvente via Método de Monte Carlo. Os espectros de absorção ótica obtidos via simulação demonstraram boa concordância com os resultados experimentais, identificando-se as bandas como oriundas das transições p-p*. Verificamos que a forma ácida aniônica do o-Abz é responsável pelo deslocamento para o azul, observado em solvente aquoso. A forma aniônica incrementa a eletronegatividade dos átomos de Oxigênio, aumentando a energia das ligações de hidrogênio. Essas ligações mais intensas estabilizam o estado excitado do o- Abz, e isso se reflete no deslocamento para azul. Da simulação, verificou-se também que na forma aniônica há uma inibição das ligações de hidrogênio do tipo doadoras por parte do grupo amina. Os derivados do o-Abz apresentam aumento na capacidade do grupo amina atuar como doador em ligações de hidrogênio e diminuição na soma de todas as ligações de hidrogênio entre soluto-solvente. Os derivados amida e monometilamida mantiveram elevado rendimento quântico e sensibilidade à polaridade ambiente. Por outro lado, o derivado o-Abz-N(CH3)2 mostra sensibilidade à presença de metilas que incrementam as vias de desexcitação não radiativa. / In the present, we report experimental and theoretical studies on orthoaminobenzoic acid (o-Abz) and its derivatives 2 amino-benzamide (o-Abz-NH2), 2 amino-monomethyl-benzamide (o-Abz-NH(CH3)) and 2 amino-dimethyl-benzamide (o-Abz-N(CH3)2. We measured optical absorption, steady state and time-resolved fluorescence and fluorescence anisotropy of the compounds in solvents with different donor/acceptor character. The experimental results were compared with results of computational calculations which simulated solvent-solute systems. Due to the restrictions imposed by the computer limitations, it was not possible to do entire quantum calculations by ab-initio methods. We used then QM/MM methods, which involves quantum calculation with molecular mechanics simulations. In this work, ab-initio and semi-empiric quantum calculations were combined in the single molecule geometry optimization and energy transitions calculus, respectively. The solute-solvent system was simulated by Monte Carlo method. The optical absorption spectra obtained from simulations showed good agreement with experimental results, identifying the bands relative to p-p* transitions. It was observed that the anionic acid form of the o-Abz is responsible for the blue shift when it is in aqueous solution. Anionic form increases the electronegativity of Oxygen atoms, rising the energy of the hidrogen bonds. These strong bonds stabilize the fundamental state of o-Abz, resulting in a blue shift in absorption spetrum. From simulation, it was verified that in the anionic form of o-Abz there is also an inhibition of hidrogen bonds of the donor type by the amine group. Compared to o-Abz alone, the derivatives present an increase in the amine group capacity to act as a hidrogen bond donor. The o-Abz-NH2 and o-Abz- NH(CH3) derivatives preserved the high quantum yield and the sensitivity for the environment polarity, while in the dimethyl amide derivative, the presence of methyl groups increases the deexcitation by non-radiactive pathways.

The replacement of artificial with natural dyes is one of the most challenging research fields in the food production area. Recent studies have shown that some frequently used synthetic colours, called the “Southampton 6 Colours” may be linked with hyperactivity in children. The purpose of this work is to analyse the degradation behaviour of black carrot, a natural, red dye commonly used for colouring food products, and subsequently improve its stability during heat and storage conditions. The stability of the black carrot mixture to heat exposure was investigated at a range of pH values by heat-treating aqueous solutions in a domestic oven at around 180oC to maintain the temperature at 100oC and the powdered material in a furnace at 180oC (typical baking conditions). 1H NMR (800 MHz) spectroscopy was used for the assignment of the aromatic chemical shifts of the black carrot mixture by overlaying them with the characterised 1H NMR chemical shifts of the individual components separated by RP-HPLC. Integration of high-resolution 1H NMR (800 MHz) spectra was used to follow the relative degradation of each of the components. Different procedures for the complexation of black carrot with metal oxides were developed, for which colourants of different colour shades were prepared. Spectroscopic techniques were used to follow the degradation of the complexes which were heat-treated at 180oC. Nano-scale investigation of the metal oxide powders was also carried out. The optimised colourants were tested on a bench scale and subsequently on an industrial scale in food pilot procedures. The successful complexes produced were found to be more heat stable compared to the commercial black carrot dye. The developed technologies are cheap and easy-to-produce methods to create intense heat and storage stable coloured pigments which can be used for the replacement of existing artificial dyes during food processing.

Iron is an essential element for life. It is involved in a number of biological processes, including iron sulfur (Fe/S) cluster assembly and heme biosynthesis. However it is also potentially toxic due to its ability to induce formation of reactive oxygen species (ROS) via Fenton chemistry. Therefore its uptake, trafficking and utilization must be regulated to avoid its toxicological effect. It has been recently discovered that Fe/S cluster biosynthesis machinery plays a key role in the cellular iron regulation and its disruption leads to impaired iron regulation and iron accumulation within mitochondria. The iron accumulation resulted from impaired Fe/S cluster assembly in the eukaryotic model organism Saccharomyces cerevisiae (baker’s yeast) was studied. Various biophysical (e.g. Mössbauer, EPR, UV-vis spectroscopy) and biochemical (e.g. Western blots, PCR, enzyme activity assay, etc.) techniques were used to characterize the iron content in yeast mitochondria isolated from several mutants strains. In these mutants one of the proteins involved in Fe/S cluster biosynthesis (Yah1p and Atm1p) is mutated and iron regulation and metabolism are disrupted. By integrating the results obtained from these different methods, it was determined that excess iron accumulates in the mutant mitochondria as inorganic phosphate Fe(III) nano-particles exhibiting superparamagnetic behaviors. Oxygen is required for iron accumulation and nanoparticle formation. The Fe(III) nano-particles can be chemically reduced to Fe(II) then largely exported from the mitochondria. These biophysical and biochemical methods were also used to examine the iron distribution in whole yeast cells of the Aft1-1up strain in which iron regulon genes are constitutively activated and compared to that of Yah1p-depleted and wild type yeast. Constitutive activation of iron regulon genes does not alter the cellular iron distribution significantly. However disruption of Fe/S cluster assembly by Yah1p depletion causes dramatic cellular iron redistribution: the vacuolar iron is largely evacuated and most of the cellular iron probably precipitates in mitochondria as Fe(III) nanoparticles. The results provide novel insights into iron trafficking and possible signal communications between organelles within cells.

A broadband coupling approach applied to a single mode, sol-gel, planar integrated optical waveguide (IOW) was used to create a multichannel attenuated total reflection (ATR) spectrometer. Initial attempts to create an achromatic coupling element for sol-gel waveguides, based upon previous work applied to vacuum deposited glass devices, did not lead to an easily achievable design. Instead a simplified, non-achromatic approach based upon impinging an incident light beam with a large numerical aperture onto an incoupling prism was used. This simplified broadband coupling approach was used to create a sol-gel IOW-ATR spectrometer that transmitted light down to at least 400 nm, and produced a measurable bandwidth of ~ 250 nm; both phenomena are marked improvements upon the capabilities of previously reported devices. An experimental demonstration of this device proved it capable of measuring the visible spectrum of a thin film of horse heart cytochrome c adsorbed to the sol-gel surface at a submonolayer coverage. The broadband spectral capabilities of this sol-gel device were also used to experimentally validate a new method for determining the angular orientation of molecules bound to an arbitrary waveguide surface. In addition to the sol-gel IOW work, the simplified broadband coupling approach was applied to a previously reported multilayered electroactive waveguide device, which was used to collect electrically modulated, broadband spectra for thin films of cytochrome c, as well as a dicarboxyferrocene moiety. Both of these IOW-ATR spectrometers represent improved tools for probing the near-surface chemical environments of molecular assemblies.

Solar cells based on CdTe absorbers are attractive due to the optimal direct band gap energy and large absorption coefficient of CdTe, however, their performance and commercialization is hindered by the lack of reliable p-type contacts. CdTe has a low carrier concentration and a large electron affinity, which results in a requirement of non-realistic work functions for metals to be used as back contacts in the solar cell. Even noble metals such as Ag present a significantly large potential barrier for holes, thereby reducing the hole current through the semiconductor/metal interface. Several attempts to resolve this challenge have been tried, however, many drawbacks have been encountered. Two particular systems, namely Cu2Te thin films and CdTe/ZnTe strained-layer superlattices, are investigated for their potential use as ohmic contacts in CdTe solar cells. A detailed analysis of the optical, electrical, and structural properties of Cu2Te thin films deposited by magnetron sputtering is presented. It is shown that these films have an indirect band gap and highly degenerate semiconductor behavior. The large p-type carrier concentration of Cu2Te films is highly desirable for the application of Cu2Te as a p-type contact to CdTe. In-depth studies of optical transitions and miniband transport in strained-layer CdTe/ZnTe superlattices are presented as well. The band offsets between CdTe and ZnTe were determined by comparison of measured and calculated optical transitions. Superlattice structures that offer best contact performance have been identified by use of tunneling probability simulations. Characterization of CdTe solar cells with above mentioned contacts indicated that contacts based on CdTe/ZnTe superlattices are a viable Cu free option for stable and reliable p-type contacts in CdTe solar cell. The contact performance of Cu2Te thin films was comparable to that of CdTe/ZnTe superlattices and both demonstrated an advantage over contacts based on ZnTe:N thin films which were used a standard.

As ferroporfirinas sintéticas são sistemas complexos que vêm sendo amplamente estudadas. A dificuldade em obter informações estruturais, reações químicas e ligantes do íon central vêm estimulando o estudo pormenorizado desses sistemas. Nestes trabalho é apresentada a caracterização da série de FeP fluorosubstituídas, que compreende as mono-, di-, tri e tetra- fluorofenilporfirina, denominadas FeTF5PP, FeTF10PP, FeTF15PP e FeTF20PP, respectivamente. Essas FeP são estudadas em função dos solventes diclorometano (DCM), metanol (MeOH) e das várias misturas em volume desses dois. As técnicas espectroscópicas de Absorção Eletrônica na região do Ultravioleta ao Visível (UV-Vis) e Ressonância Paramagnética Eletrônica (EPR) são as duas ferramentas de estudos escolhidas para caracterizar esses sistemas. Partindo-se de uma solução de FeP dissolvida em DCM, foram adicionadas alíquotas de Me0H até completar-se 50% em volume desses dois solventes. Através dessa titulação, observamos a formação de diferentes espécies como conseqüência da coordenação do Me0H à FeP. Notamos também, as modificações estruturais reveladas principalmente pelo EPR, ocasionadas pelos diferentes números de substituintes fluorofenis. Essa técnica espectroscópica revelou ainda a existência de interações que não foram anteriormente observadas. Para a FeTFloPP foi verificada a interação super hiperfina entre o Fe e o ligante CF além da interação super hiperfina entre o Fe e os nitrogênios do anel porfirínico. Para a FeTF20PP foi verificada apenas a interação super hipeOna entre o Fe e o ligante Cl-. As demais FeP não apresentaram essas interações / Synthetic iron porphyrins are complex systems that have been largely studied. Difficulties to obtain structural information, chemical reactions and ligands of the central ions have been a subject to investigate details of these systems. In this work, a systematic characterization of one series of fluorophenyl iron porphyrins is presented. Mono-, di-, tri- and tetrafluorophenyl substituents called FeTF5PP, FeTF10PP, FeTF15PP, and FeTF20PP, respectively, are included in this series. Iron porphyrins were studied as a function of dichloromethane, methanol solvents and several of their mixture in volume. These systems were characterized by Ultraviolet- Visible and Electron Paramagnetic Resonance Spectroscopes. From iron porphyrin solutions, dissolved in dichloromethane, aliquots of methanol were added up to 50% in volume of these two solvents. With this titration, we found different species because of the methanol coordination to the iron porphyrins. We also observed the structures modification revealed by the EPR spectroscopy, as a function of different numbers of fluorophenyl substituents. The EPR spectroscopy also revealed the existence of the super hyperfine interactions not observed before. It was found for FeTFloPP between the central ion and the axial ligand chlorine Cl - ion, besides the hyperfine interaction between iron and the nitrogen of the pyrrole ring. For FeTF20PP only the super hyperfine interaction, Fe-C1 was found. These interactions were not observed for the other iron porphyrins

Nesta tese, apresentamos estudos experimentais e teóricos realizados com o Ácido orto-Aminobenzóico (o-Abz) e seus derivados 2-amino-benzamida (o-Abz-NH2), 2-amino-metil-benzamida (o-Abz-NH(CH3)) e 2-amino -dimetilbenzamida (o-Abz-N(CH3)2). Foram feitas medidas de absorção óptica, fluorescência estática e resolvida no tempo e anisotropia de fluorescência em solventes com diferentes graus de polaridade e diferentes capacidades de doar e aceitar prótons. Os resultados experimentais foram comparados aos resultados de simulações computacionais que simularam o sistema solventesoluto. Restrições impostas pelas limitações computacionais impedem cálculos totalmente quânticos via métodos ab-initio, porém uma metodologia que tem apresentado resultados satisfatórios é o método híbrido que envolve a mecânica quântica associada à mecânica molecular (QM/MM). No presente trabalho, foram combinados cálculos quânticos ab-initio e semi-empíricos na otimização de geometrias de moléculas isoladas e no cálculo de energias de transições respectivamente. Foram simulados os sistemas soluto+solvente via Método de Monte Carlo. Os espectros de absorção ótica obtidos via simulação demonstraram boa concordância com os resultados experimentais, identificando-se as bandas como oriundas das transições p-p*. Verificamos que a forma ácida aniônica do o-Abz é responsável pelo deslocamento para o azul, observado em solvente aquoso. A forma aniônica incrementa a eletronegatividade dos átomos de Oxigênio, aumentando a energia das ligações de hidrogênio. Essas ligações mais intensas estabilizam o estado excitado do o- Abz, e isso se reflete no deslocamento para azul. Da simulação, verificou-se também que na forma aniônica há uma inibição das ligações de hidrogênio do tipo doadoras por parte do grupo amina. Os derivados do o-Abz apresentam aumento na capacidade do grupo amina atuar como doador em ligações de hidrogênio e diminuição na soma de todas as ligações de hidrogênio entre soluto-solvente. Os derivados amida e monometilamida mantiveram elevado rendimento quântico e sensibilidade à polaridade ambiente. Por outro lado, o derivado o-Abz-N(CH3)2 mostra sensibilidade à presença de metilas que incrementam as vias de desexcitação não radiativa. / In the present, we report experimental and theoretical studies on orthoaminobenzoic acid (o-Abz) and its derivatives 2 amino-benzamide (o-Abz-NH2), 2 amino-monomethyl-benzamide (o-Abz-NH(CH3)) and 2 amino-dimethyl-benzamide (o-Abz-N(CH3)2. We measured optical absorption, steady state and time-resolved fluorescence and fluorescence anisotropy of the compounds in solvents with different donor/acceptor character. The experimental results were compared with results of computational calculations which simulated solvent-solute systems. Due to the restrictions imposed by the computer limitations, it was not possible to do entire quantum calculations by ab-initio methods. We used then QM/MM methods, which involves quantum calculation with molecular mechanics simulations. In this work, ab-initio and semi-empiric quantum calculations were combined in the single molecule geometry optimization and energy transitions calculus, respectively. The solute-solvent system was simulated by Monte Carlo method. The optical absorption spectra obtained from simulations showed good agreement with experimental results, identifying the bands relative to p-p* transitions. It was observed that the anionic acid form of the o-Abz is responsible for the blue shift when it is in aqueous solution. Anionic form increases the electronegativity of Oxygen atoms, rising the energy of the hidrogen bonds. These strong bonds stabilize the fundamental state of o-Abz, resulting in a blue shift in absorption spetrum. From simulation, it was verified that in the anionic form of o-Abz there is also an inhibition of hidrogen bonds of the donor type by the amine group. Compared to o-Abz alone, the derivatives present an increase in the amine group capacity to act as a hidrogen bond donor. The o-Abz-NH2 and o-Abz- NH(CH3) derivatives preserved the high quantum yield and the sensitivity for the environment polarity, while in the dimethyl amide derivative, the presence of methyl groups increases the deexcitation by non-radiactive pathways.

This diploma thesis is focused on the determination of distribution a surfactant at phase separation in polymer-surfactant system. Sodium hyaluronate of three molecular weights was chosen as a polymer, CTAB was used as a surfactant. The experiments were performed in an environment of 0,15 M NaCl. The measurement of the CTAB concentration in samples was based on the formation of coloured complexes of CTAB and picric acid in chloroform. UV-VIS spectroscopy was used for the detection of these complexes. The content of CTAB was determined in four gels of different composition (2% Hya + 200 mM CTAB, 2 % Hya + 50 mM CTAB, 0,5 % Hya + 200 mM CTAB, 0,5 % Hya + 50 mM CTAB). All gels were gradually washed five times with 0,15 M NaCl. The content of CTAB was determined for newly prepared gels and for gels after 2 and 4 months since the preparation. Initial concentrations of CTAB and hyaluronan have greater influence on the distribution of CTAB after phase separation, than the molecular weight of hyaluronan. The content of CTAB in newly prepared gels and after 4 months since preparation is very similar and demonstrates the stability of the system.