Doutorado em Química (IQ)
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Item Compostos de coordenação com um ligante do tipo oxamato derivado do ácido 4-aminobenzóico: Síntese, Caracterização e estudo das propriedades ópticas e magnéticas(Universidade Federal de Goiás, 2024-12-01) Maciel, Jhonny Willians de Oliveira; Gomes, Danielle Cangussu de Castro; http://lattes.cnpq.br/5709288358367849; Gomes, Danielle Cangussu de Castro; Silva, Hermínia Veridiana dos Santos Pessoni e; Ferreira, Leonildo Alves; Gonçalves, Pablo José; Simão, Tatiana Renata GomesIn this work, we present the syntheses, characterizations, and studies of the optical and magnetic properties of various novel coordination compounds. We obtained supramolecular systems based on complexes with the ligand Sodium 4- (carboxylatoformamido)benzoate (Na2Hpcpa) and the heavy metal ions Cd2+ and Pb2+, as well as a series of isostructural complexes containing the rare earth metal ions Y3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+, and Yb3+. The studies of the optical properties of the Cd2+ and Pb2+ compounds show a shift in the emission band position towards white light when compared to the matrix's emission. The Eu3+ and Tb3+ compounds exhibit red and green emissions, respectively, with high thermal stability over the entire temperature range studied, between 16 and 300 K. The external quantum yield for the Tb3+ compound was considerably improved compared to compounds containing oxamate-type ligands reported in the literature, indicating that the ligand Hpcpa2- may be an efficient sensitizer for energy transfer through the so-called antenna effect to Tb3+ ions. Magnetic properties studies of the Eu3+, Gd3+ , Tb3+, and Er3+ compounds were conducted, and ac susceptibility measurements reveal that the Gd3+, Tb3+, and Er3+ compounds exhibit slow relaxation of magnetization induced by the magnetic field, thus representing new examples of field-induced single-molecule magnets (SMMs). Despite the Y3+, Eu3+, Ho3+, Er3+, and Yb3+ compounds not having well-defined single-crystal X-ray diffraction structures, other structural characterizations indicate that all rare earth Ln3+ compounds obtained in this work are isostructural to the Eu3+, Gd3+, and Tb3+ compounds with defined structures. Therefore, among the compounds obtained in this work, the Tb3+ compound can be classified as multifunctional with possible dual technological applications, optical and magnetic.Item Estudos da síntese e crescimento de carbonatos de cálcio e magnésio sintéticos(Universidade Federal de Goiás, 2024-11-29) Pimentel, Hannah Larissa Siqueira Matos; Oliveira, Cecilia Maria Alves de; Carvalho, Jesiel Freitas; http://lattes.cnpq.br/5841291496427516; Carvalho; Martins, Felipe Terra; Leles, Maria Inês Gonçalves; Buifaçal, Leandro Felix de Souza; Neto, Jose de Araujo NogueiraEmbargado.Item Uso de terapia fotodinâmica antimicrobiana para o tratamento de Klebsiella pneumoniae produtora de carbapenemase (KPC-Kp)(Universidade Federal de Goiás, 2025-03-28) Freitas, Alysson Benite de; Souza, Guilherme Rocha Lino de; http://lattes.cnpq.br/1127532567066692; Gonçalves, Pablo José; http://lattes.cnpq.br/0515343409614452; Gonçalves, Pablo José; Bailão, Elisa Flávia Luiz Cardoso; Chagas, Rafael Pavão das; Iglesias, Bernardo Almeida; Chaves, Andréa RodriguesEmbargadoItem Síntese de selanil-(hetero)arenos via selenilação da ligação C(sp2)-H promovida por Ácido Tricloroisocianúrico (TCCA)(Universidade Federal de Goiás, 2025-02-03) Granja, Isis Juliane Arantes; Saba, Sumbal; http://lattes.cnpq.br/0113770075520231; Saba, Sumbal; Silva, Fabiana Ourique da; Barbosa, Martin Schwellberger; Alisson Rodrigues Rosário, Alisson Rodrigues Rosário; Goncalves, Pablo JoseThis thesis proposes a sustainable and efficient methodology for the direct selenylation of (hetero)arenes via selective C(sp2)-H bond functionalization, usmg trichloroisocyanuric acid (TCCA) as an oxidizing agent. The goal was to develop a synthetic strategy that eliminates the need for metal catalysts and toxic solvents, aligning with Green Chemistry principies. The methodology involved mild reaction conditions, employing TCCA as the oxidant and ethanol as a green solvent. Various reaction conditions were explored to optimize the selective introduction of organoselenium groups into N-heteroarenes such as imidazo[l,2-a]pyridine, imidazo[2, 1-b ]thiazole, and indole. The experiments yielded impressive results, ranging from 39% to 97%, with an average of 75%. Mechanistic investigations revealed two main pathways for functionalization, with the electrophilic activation of diselenides proving to be the most efficient. The results highlight the methodology's high selectivity and broad functional group tolerance, setting it apart from traditional approaches. Additionally, this strategy enables efficient functionalization of aromatic and heterocyclic substrates without the need for directing groups or metal catalysts, expanding its synthetic scope. The versatility of this approach opens new possibilities for future research in organic chemistry, including the selective modification of 1tconjugated systems and the construction of novel molecular structures. Overall, the findings reinforce the importance of sustainable chemistry in the synthesis of organochalcogen compounds, providing an efficient and environmentally friendly method for obtaining selenylated derivatives with potential applications across various fields of organic chemistry.Item Development of disposable microfluidic devices for bioanalytical applications(Universidade Federal de Goiás, 2024-11-21) Mendes, Geovana de Melo; Duarte, Gabriela Rodrigues Mendes; http://lattes.cnpq.br/9005971441891787; Varenne, Anne; Duarte, Doutora Gabriela Rodrigues Mendes; Coltro, Wendell Karlos Tomazelli; Silva, José Alberto Fracassi da; Varenne, Anne; Lunte, SusanThis thesis was conducted as part of a joint supervision between the Universidade Federal de Goiás (Goiânia, Brazil) and Chimie ParisTech PSL. Initiated in Brazil at the onset of the pandemic, the work developed during the Ph.D. at the Brazilian institution focused on developing LAMP-based methodologies for COVID-19 diagnosis. Loop-mediated isothermal amplification (RT-LAMP) was used to create a simple and low-cost test during the COVID-19 pandemic. This test was implemented at the point of care in an overwhelmed hospital where standard tests were not feasible, providing rapid and accurate diagnoses. Additionally, we proposed a non-invasive tracking method based on RNA extracted from the saliva of essential workers during the pandemic, which proved practical and effective for frequent testing. The preliminary transposition of this methodology to a paper-based platform showed promising results for realtime monitoring of infections, particularly SARS-CoV-2, at the point of care. Within the scope of the cotutella, subsequent work was carried out in the French laboratory to develop and optimize a paper-based platform for protein isoelectric focusing, aiming to integrate proteomic analysis steps into a microdevice. In this thesis, we developed diagnostic systems for biomolecules applied or applicable at the point of care. For protein analysis, isoelectric focusing on a paper-based platform allowed precise and reproducible protein separation, including in real samples, with acceptable resolution and efficiency. This system represents a significant step forward in a broader project aimed at integrating all proteomic steps into a single chip. The successful development of biomolecule analysis methods prioritizing cost-effectiveness, speed, and simplicity highlights the potential of paper as a platform for these diagnostic tests. Paper proved to be a suitable and accessible platform for conducting these tests, emphasizing its potential in resource-limited settings.Item Dispositivos sob demanda: desenvolvimento de sistemas microfluídicos e sensores eletroquímicos por impressão 3D(Universidade Federal de Goiás, 2020-11-30) Duarte, Lucas da Costa; Coltro, Wendell Karlos Tomazelli; http://lattes.cnpq.br/8302650734477213; Coltro, Wendell Karlos Tomazelli; Lago, Claudimir Lucio do; Muñoz, Rodrigo Alejandro Abarza; Bonacin, Juliano Alves; Vaz, Boniek Gontijo3D printing technology has been widely explored as an alternative method of manufacturing analytical microdevices. This technology has been solving many limitations of conventional microfabrication techniques due to its ability to build microstructures with different materials and geometries in a simple, fast and low-cost way. In this sense, this thesis describes the use of 3D printing to manufacture analytical platforms for applications involving counting E. coli cells embedded in droplets based on contactless conductometric detection (C4D), online monitoring of chemical reactions by mass spectrometry (MS) and estradiol detection in electrochemical analysis. For C4D measurements, microfluidic devices were printed containing Tjunction microchannels and two electrodes integrated in the antiparallel arrangement. The droplets with incorporated cells were monitored in real time using the C4D system. The proposed approach demonstrated the ability to detect E. coli cells in the concentration range between 86.5 and 8650 CFU droplet-1 with a detection limit of 63.66 CFU droplet-1. For the development of the miniaturized reactor used in the monitoring of chemical reactions by MS, a microfluidic device was built containing a channel in the shape of a 3D serpentine and another one containing a channel in the Y-shaped. Both devices were evaluated for monitoring the Katritzky reaction, injecting simultaneously 2,4,6-triphenylpriryllium (TPP) and amino acid (glycine or alanine) solutions and the reaction product were monitored online by MS at different flow rates. The acquired spectra demonstrated that the relative abundances of the products obtained with the device containing the 3D serpentine channel had an order of magnitude up to three times greater than those obtained with the Y-shaped device. The device performance in 3D serpentine was also evaluated comparing with the traditional ESI(+)-MS technique. The 3D serpentine printed reactor promoted the reaction quickly and with a higher rate of product formation compared to the ESI(+)- MS technique. The electrochemical cell containing integrated electrodes was entirely manufactured by 3D printing. The electrochemical device was manufactured in a single step with a manufacturing time of 12 min and a cost of US$ 0.08. Preliminary tests for the detection of 17β - estradiol by DPV reached an LOD of 0.1 μmol L-1 and an analytical curve with a linear range of 0.19 to 25 μmol L-1. These results demonstrate the excellent versatility of 3D printing technology being applied in different areas of bioanalytical chemistry. The counting method of counting bacteria, the device for online monitoring of chemical reactions, as well as the electrochemical cell for detection of hormones offer instrumental simplicity, low cost, high sensitivity, allowing the opening of new application possibilities in different areas of chemistry.Item As Licenciaturas em Química EaD nos IF e a Heutagogia como elemento basilar nos modelos de formação docente(Universidade Federal de Goiás, 2024-08-27) Alves, Dylan Ávila; Mesquita , Nyuara Araújo da Silva; http://lattes.cnpq.br/6971106875143413; Mesquita , Nyuara Araújo da Silva; Cassiano, Karla Ferreira Dias; Lima, Daniela Da Costa Britto Pereira; Soares, Marlon Herbert Flora Barbosa; Silva Filho, Juvenal Carolino DaThis research aims to investigate the educational methodologies present in distance Chemistry Licentiate courses (LQ). It utilizes the theoretical perspectives of adult education in distance courses (Heutagogy) proposed by Stewart Hase and Chris Kenyon. The goal is to contribute to the discussion of the methodologies used in distance Chemistry courses at Federal Institutes (IF) that facilitate the learning process in these courses. The doctoral thesis was structured from chapters in the format of articles. For the conclusion of the thesis, three chapters/articles were developed titled: 1- Tensions in the Landscape of Chemistry Licentiate Programs in Brazil: Distance Education in Public and Private Spheres; 2- Heutagogy as a Methodology for Teacher Training at a Distance: An Overview of Brazilian Research; 3- An Analysis of Distance Chemistry Licentiate Programs in Federal Institutes from the Perspective of Heutagogical Learning Design Elements. Chapter 1 presents results from the survey of distance Chemistry Licentiate programs (LQ) in public and private higher education institutions (IES) in 2021, conducted through the e-MEC portal. A descriptive study with a quantitative-qualitative approach was used. The distance LQ programs represent a total of 20 courses in public institutions and 25 in private ones. The study highlights a trend towards teacher training through distance education, especially in private IES, but it also indicates the need for public institutions to investigate distance education training. Chapter 2 presents a survey of the main publications related to the Heutagogy theme in the Database of Theses and Dissertations (BDTD) from CAPES and in Portuguese journals. The research is configured as the "state of the art," divided into two moments: the first addresses the inventory of publications from 2010 to 2022, and the second identifies the trends in the publications regarding the theme. A total of 14 publications were surveyed, including five in the BDTD and nine in scientific articles. Initially, an analysis category was established as "Teacher Training," but two categories emerged: Distance Education and Heutagogy as a methodology. The study shows that there is no clear direction in research towards teacher training courses, but it presents Heutagogy as a potential theoretical reference in distance Licentiate courses. Chapter 3 analyzes the curricular proposals (PPC) of distance LQ courses in IF, based on the six learning elements proposed by Blaschke and Hase (2016). It was possible to reveal that the LQ programs present some learning elements in the documents, which can be evidenced in disciplines, evaluation criteria, supervised internships, curricular components, tutorial activities, among others.Item Análise computacional da solvatação do diclofenaco e interações da melatonina com radical hidroxila: abordagens via dinâmica molecular e teoria do funcional da densidade(Universidade Federal de Goiás, 2024-11-14) Rodrigues, Allane Catharina Carvalhaes; Oliveira, Heibbe Cristhian Benedito de; http://lattes.cnpq.br/5995553993631378; Oliveira, Heibbe Cristhian Benedito de; Perez, Caridad Noda; Borges, Leonardo Luiz; Gargano, Ricardo; Lima, Igo TorresComputational chemistry represents an understanding of chemistry as the manifestation of the behavior of atoms and molecules. This active research field, spanning over a decade, employs mathematical techniques and algorithms to model and simulate chemical influences. The application of computational chemistry is crucial in material design, drug development, and the comprehension of biological processes. Analyzing solute-solvent interactions underscores the importance of physicochemical properties in chemical research, whereas the investigation of free radical elimination is essential for physiological balance. Within this context, the proposed study aims to comprehend the mechanisms of hydroxyl radical removal by melatonin and evaluate the aqueous solvation process of diclofenac through molecular modeling, employing Car-Parrinello and Born-Oppenheimer molecular dynamics, in addition to Density Functional Theory. Results from the dynamics of reactions between the •OH radical and melatonin provide a detailed understanding of various involved conditions, emphasizing the crucial influence of variables such as speed, temperature, and attack direction. The reaction with the hydrogen bonded to the nitrogen of the indole group (called H22) is the more favorable. Energy profiles and rate constants support H22 as the most likely path, providing comprehensive insights into the kinetic and thermodynamic characteristics of the interactions. Our findings regarding diclofenac solubility in water highlight the formation of important intermolecular hydrogen bonds between the atoms of diclofenac with water molecules (OH⋯Owater and CO⋯Hwater). The OH⋯Owater bond is exceptionally strong, similar a covalent bond. Additionally, we observe intramolecular hydrogen bonds in the diclofenac molecule (NH⋯OH e NH⋯Cl) and weaker interactions involving CH⋯Cl. Remarkably, diclofenac protonation contributes to molecular rigidity, hindering future hydrogen bonds with adjacent water molecules, directly impacting molecule solubility. Advancements in this field promise to enrich fundamental chemistry understanding and drive practical advancements in various areas, such as pharmacology, molecular biology, and industrial chemistry.Item Aplicação da tecnologia supercrítica no tratamento de resíduos plásticos presentes em amostras de água(Universidade Federal de Goiás, 2023-12-21) Viana , Júlio Cezar Vieira; Alonso, Christian Gonçalves; http://lattes.cnpq.br/7285754665946583; Alonso, Christian Gonçalves; Montel, Adão Lincon Bezerra; Silva, Donizete Xavier da; Oliveira, Heibbe Cristhian Benedito de; Brito, Nubia Natalia dePhthalic acid esters (PAEs) and bisphenol A (BPA) are plastic waste classified as emerging organic contaminants that can harm biota and human health. These residues arise as a result of the fragmentation of plastics into their monomers or the leaching of compounds used as plasticizers, such as BPA and DEP. In addition to contaminants of emerging concern, these compounds are also classified as endocrine disruptors (EDCs), interacting with estrogen receptors and causing harm to human health and the environment. Even with the availability of physical and chemical wastewater treatment methods, classical treatment methods for these compounds have proven not to be efficient in removing these refractory compounds. Therefore, the objective of this work was to use supercritical water oxidation (OASC) technology to investigate the degradation of BPA and DEP plastic waste in aqueous samples. The variables flow rate, temperature, concentration of oxidizing agent (H2O2) and homogeneous and heterogeneous catalyst, such as Cu(NO3)2 and metallic copper wire, respectively were used as parameters for the tests. Metallic copper was also used in the form of a wire together with H2O2. After treatment using OASC Total organic carbon (TOC) removal efficiencies were found to increase linearly with increasing temperature in the range of 400°C to 700°C for all tests with BPA and DEP. For all tests carried out, the best efficiency in removing total organic carbon (TOC) for BPA was achieved at a temperature of 700°C, oxidant concentration of 60 mM and flow rate of 10 mL.min-1 , reaching 91% of removal. For DEP, the best removal efficiency was achieved at a temperature of 700°C, oxidant concentration of 23 mM and flow rate of 10 mL.min-1, achieving 85% removal. Gas chromatography analysis was carried out for the gaseous components and revealed the presence of hydrogen, carbon dioxide, ethane, ethylene, methane and carbon monoxide gases. The analysis of the liquid fraction for BPA samples in the best treatment condition was carried out using liquid chromatography coupled to mass spectrometry and revealed the presence of the intermediate 2-phenyl2-propanol as the main degradation product. The liquid fraction for DEP samples in the best treatment condition was performed by gas chromatography coupled to mass spectrometry and revealed the presence of aliphatic chain hydrocarbons, such as decosane, triacontane, tetracosane and eicosane as the main degradation products. Therefore, the use of supercritical technology proved to be an efficient method for treating aqueous samples containing BPA and DEP.Item Aplicações da cromatografia líquida e espectrometria de massas na análise de contaminantes em amostras de leite bovino e arroz para fins de controle de qualidade e segurança em alimentos(Universidade Federal de Goiás, 2024-03-28) Soares, Daniel de Almeida; Chaves, Andréa Rodrigues; http://lattes.cnpq.br/6064014965252121; Chaves, Andréa Rodrigues; Rezende, Cintia Silva Minafra e; Lima, Leomir Aires Silva de; Alves, Maria Isabel Ribeiro; Brito, Nubia Natalia DeThe present study uses liquid chromatography and mass spectrometry approaches as tools for identifying and quantifying contaminants in foods, such as rice and bovine milk. For the sake of comprehension, this study is divided into four stages: 1) Development of an LC-MS methodology for quantifying the antibiotic ceftiofur in bovine milk samples; 2) Determination of bisphenols (A and S) in long-life milk and its respective packaging by Paper Spray Ionization (PSI-MS); 3) Development of a methodology for determining herbicides in rice (Oryza sativa) samples using the miniaturized hollow fiber liquid phase microextraction sample preparation technique (HF-LPME) with electrospray ionization analysis (ESI-MS); 4) Chemometric analysis comparing rice samples contaminated with fungicides and not contaminated from direct analysis by ESI-MS. In step 1, to determine ceftiofur in milk samples, a liquidliquid extraction (ELL) method was developed followed by analysis of the extracts by LC-MS. The main variables associated with the extraction process were optimized and the figures of merit: linearity, limit of detection and quantification (LOD and LOQ), precision and recovery were evaluated. The method presented LOQ 0.80 ng.mL-1 , inter-day precision of less than 7.3% and recovery greater than 94%. Milk samples obtained from cows subjected to antibiotic application were analyzed for the purpose of evaluating the antibiotic elimination profile in the milk samples. In part 2, it was possible to develop a rapid method for analyzing bisphenols (BPA and BPS) in longlife milk samples and their respective packaging using ambient mass spectrometry using the PSI-MS technique. The method was optimized and the figures of merit linearity, precision, accuracy, LOQ and LOD were evaluated, all of which were within the parameters required by national legislation. The bisphenols under study were detected in all samples (packaging and milk) and in only one sample the BPA content was above 10 ng.mL-1 (maximum residue limit) and for BPS the majority of samples presented levels above the same concentration. In milk, a content of up to 150 ng.mL1 for BPA and an average content of 60 ng.mL-1 for BPS was obtained. The results of this study were published in the journal Food Chemistry (qualis A1). In chapter 3, the use of the miniaturized HF-LPME sample preparation technique followed by ESI ionization mass spectrometry analysis for the determination of herbicides in rice is presented. The main parameters relating to the sample preparation method were optimized, with the use of a two-phase system resulting in shorter extraction times. However, in a three-phase system, with the donor phase at pH 1.7 and the acceptor phase at pH 12, extraction was favored for all analytes. The ionic strength was evaluated by adding salt to the donor solution and did not favor extraction. Therefore, the three-phase system presented a better response to the analytes and the method should have its figures of merit evaluated using the optimized HF-LPME/ESI-MS method. The fourth chapter presents a metabolomic analysis followed by chemometric treatment of data obtained by ESI-MS analysis on rice extract samples using positive and negative modes. A comparison of samples was carried out in 4 different matrices (rice husk, grain with husk, polished grain without husk and unpolished grain without husk). The samples evaluated were divided into two groups: contaminated with fungicides and not contaminated. The data obtained made it possible to separate them into classes using treatments using principal component analysis (PCA). In ESI(-) mode, the data were better explained by PCA Without normalization (89.1%) and also by Quantile Normalization (90%). The negative mode better explains the dissimilarity between the contaminated and uncontaminated rice groups.Item Sensores miniaturizados para COVID-19 e paracetamol: uma abordagem simples e de baixo-custo(Universidade Federal de Goiás, 2024-10-09) Moreira, Nikaele Sousa; Coltro, Wendell Karlos Tomazelli; http://lattes.cnpq.br/8302650734477213; Coltro, Wendell Karlos Tomazelli; Souza , Endler Marcel Borges de; Pedrino, Gustavo Rodrigues; Meloni, Gabriel Negrão; Chaves, Andrea RodriguesThis work describes the development of miniaturized sensors on accessible and low-cost substrates to detect the spike protein (S) of the SARS-CoV-2 virus and paracetamol in whiskey samples. Protein S is a marker associated with COVID-19, which is present on the external part of the virus and has an affinity with the human angiotensin-converting enzyme 2 (hACE2), allowing the infection of human cells. Therefore, its detection is of great importance for an early diagnosis of the disease. In this context, polyester microplates were developed for the colorimetric detection of this protein in biological samples based on a direct ELISA assay for rapid detection and with less use of reagents, in addition to good clinical accuracy. A linear range was obtained in protein S concentrations of 0-10 μg mL-1, with a coefficient of determination (R2) equal to 0.991 and a limit of detection 0.44 μg mL-1. The proposed methodology revealed satisfactory intraplate and interplate repeatability with standard deviation values below 7.7%. Thirty-seven saliva and swab samples from positive and negative patients were evaluated for the presence of the virus. The results were consistent with the RT-PCR method, showing 100% sensitivity and 85.71% specificity for saliva samples. For nasopharyngeal samples, sensitivity was 90% and specificity was 100%. In addition, it revealed diagnostic accuracy above 94%, indicating that the proposed method can predict more than 94% of the samples correctly. Adulteration of whiskey is a common practice in nightclubs due to the high cost of these original drinks. Counterfeiters often add medications or pharmaceuticals to mask the effects of a hangover, for example, paracetamol, as it is an over-the-counter analgesic indicated for the treatment of headaches. Therefore, distance-based detection of paracetamol in whiskey samples using a paper-based microfluidic analytical device (μPAD) is imperative since the use of paper substrate offers excellent benefits, such as accessibility, portability, and the ability to detect paracetamol without expensive instrumentation. Optimal detection conditions were achieved by introducing 5 μL of a mixture containing 7.5 mmol L-1 of Fe(III) and K3[Fe(CN)6] into the detection zone, together with 12 μL of whiskey samples into the sample zone. The method showed linear behavior in the 15 to 120 mg L-1 concentration range, with R2 equal to 0.998. Paracetamol was quantified in spiked samples using the proposed method, and the results were compared with those of a spectrometric method. No significant differences were observed at the 95% confidence level. The method determined approximately 1 drop of the drug paracetamol of 200 mg mL-1 in 1 L of solution, demonstrating excellent sensitivity. Therefore, the proposed methods are alternatives for practical, simple and economical analyses and reduce the consumption of samples, reagents and waste. Then, they have great potential to be used in the field for clinical applications in diagnosing COVID-19 and forensic applications for detecting paracetamol in beverages.Item Síntese de tri-heterociclos pentadienos e estudo de suas propriedades luminescentes(Universidade Federal de Goiás, 2023-05-09) Matos, Gabriela Ferreira; Kato, Lucilia; http://lattes.cnpq.br/1362891438631386; Kato, Lucilia; Coelho, Felipe Lange; Barros, Olga Soares do Rego; Gonçalves, Pablo José; Santos Neto, José Sebastião dosThis study presents the synthesis of diois (1-4(a-h) and 5, Scheme 1), building blocks commonly used in designing and preparing heteroporphyrins. The synthesis of compounds 1 and 2 has been largely reported in the literature. On the other hand, there are few or no examples of synthetic routes for chalcogen-heteroaryl-substituted compounds such as 3 and 4 (Scheme 1), which constitutes a great challenge. Among the obtained products, thirty-seven molecules are new: five diols, thirty triheteropentadienylmethanes and two porphyrins. Chemical and structural characterization of the compounds 1-4(a-h), 5a and 6 were confirmed through a variety of analytical and spectroscopic techniques: High-Resolution Mass Spectrometry (HRMS), Nuclear Magnetic Resonance (NMR) by 1D and 2D, IR and UV spectroscopy. In addition, X-ray quality single-crystals of 3a allowed the determination of its relative stereochemistry as being (-)-RR-2,5-bis((4-methoxyphenyl)(thiophen-2yl)methyl)thiophene or (-)-SS-2,5-bis((4-methoxyphenyl)(thiophen-2-yl)methyl)thiophene. Unexpected fluorescence emission was observed when compounds triheteropentadienylmethanes were exposed to UV radiation, as shown in Figure 1. The photophysical studies of compounds 2a and 3a revealed a similar absorption profile, with the absorption bands in the violet-to-blue region (between 440-470 nm). Moreover, neither the distinct solvents (ACN, Dioxane, EtOH and CH2Cl2) nor the aryl-substituents (R, Scheme 1) nor the heteroatom (X, Scheme 1) affect significantly the HOMO-LUMO transition energy. In 2a, there is a dependence of the emission wavelength with the excitation wavelength. This fact may indicate that these compounds are examples of molecules exhibiting the non-traditional intrinsic luminescence phenomena.Item Novas abordagens para determinação de melatonina e metabólitos em leite materno e aplicação da metabolômica para fins de diferenciação de cultivares de alface(Universidade Federal de Goiás, 2024-09-11) Machado, Lucas Santos; Roque, Jussara Valente; http://lattes.cnpq.br/7154037221725381; Chaves, Andréa Rodrigues; http://lattes.cnpq.br/6064014965252121; Chaves, Andréa Rodrigues; Bottoli, Carla Beatriz Grespan; Silva, Bruno José Gonçalves da; Faria, Anízio Márcio de; Sgobbi, Lívia FlórioIn analytical chemistry, there is a constant search for methodologies that require less cost and analysis time, but at the same time offer precision and accuracy. In this sense, various methodologies and technologies have been evaluated, among which we can highlight those that employ miniaturized sample preparation techniques and those that use ambient ionization sources for mass spectrometry. This thesis is divided into two chapters presenting the potential of modern sample preparation techniques for liquid chromatography analysis and ambient mass spectrometry analysis. The first chapter describes the use of disposable pipette extraction, utilizing a sorbent phase based on molecularly imprinted polymers (DPX-MIP), for the determination of melatonin and its metabolites (AFMK and AMK) in breast milk by liquid chromatography coupled with mass spectrometry (LC-MS). Different MIPs were synthesized and evaluated for their selectivity in analyzing melatonin and its metabolites, experimentally obtained results were compared with molecular simulation data, showing consistency between the theoretical physicochemical parameters and the experimental data. The application of DPX-MIP in conjunction with LC-MS enabled the development of a method for determining melatonin and its metabolites in breast milk, with recovery values ranging from 87-111% and precision between 2-13%, analysis of patient samples produced values consistent with those reported in the literature. The second chapter explores the application of the paper spray ionization mass spectrometry (PSI-MS) technique to study the metabolomics of lettuce cultivars and the potential differentiation according to their cultivation method and variety. PSI-MS, an ambient ionization technique, uses chromatographic paper as a substrate for the sample ionization process. In this study, lettuce samples were successfully differentiated according to variety and cultivation method through the application of chemometric tools (PARAFAC, PCA, PLS-DA, and OPSDA), identifying 36 metabolites responsible for this differentiation, with choline, mannose, and citric acid being the most influential. Additionally, green chemistry metrics, such as AGREEprep and AGREE, were applied to assess the sustainability of the developed methodologies. The results confirmed that DPX-MIP and PSI-MS are more sustainable, offering appropriate analytical performance with shorter analysis times and generating low volumes of chemical wasteItem Manufatura aditiva circular: utilizando e reciclando materiais termoplásticos para desenvolver sensores analíticos(Universidade Federal de Goiás, 2024-02-05) Silva Neto, Habdias de Araujo; Coltro, Wendell Karlos Tomazelli; http://lattes.cnpq.br/8302650734477213; Coltro, Wendell Karlos Tomazelli; Carrilho, Emanuel; Muñoz, Rodrigo Alejandro Abarza; Janegitz, Bruno Campos; Chaves, Andréa RodriguesAdditive printing technologies have emerged as powerful tools for the development of portable analytical instrumentation including electrochemical sensors. Before using the device, pre-treatment methods are required to improve the electrochemical performance. Additionally, the additive printing method used thermoplastic polymers that can be harmful to the environment compartments. In this report, we successfully developed five different strategies to manufacture 3D-printed electrodes and have also introduced an initiative for recycling thermoplastic materials in order to create electrodes on paper substrate, contributing to the circular economy. The ecological impact of each proposed method was evaluated also. An activation process was performed by using Fenton's reagents, H2O2 (15%, v/v) and Fe (10 mg L-1 ) in the presence of ultraviolet radiation (5 min), followed by an electrochemical oxidation step in the presence of acetic acid (1.8 V vs C for 200 s). The proposed activation method has used non-toxic reagents and showed excellent improvement in the electrochemical responses with long-term stability (~ 2 months). The manufactured 3D-printed electrodes have exhibited suitable values of limit of detection (at µmol L-1 levels) for different analytes, including metals such as Cd(II) (0.009; 1.01 µg L-1 ) and Pb(II) (0.006; 1.24 µg L-1 ), midazolam maleate (0.54) , uric acid (0.71), adrenaline (0.61), S-nitroso-cysteine (4.1) and folic acid (5.1). In addition, the analytical methodologies described here also demonstrated an excellent ecological profile according to the 12 principles of Green Analytical Chemistry.Item Implantação das técnicas espectroscópicas de Laser FlashFotólise e de fosforescência para estudos fotofísicos de sistemas porfirínicos e suas interações com biomoléculas e nanoestruturas(Universidade Federal de Goiás, 2023-12-14) Ducas, Eli Silveira Alves; Gonçalves, Pablo José; http://lattes.cnpq.br/0515343409614452; Gonçalves, Pablo José; Coelho , Felipe Lange; Gomes, Danielle Cangussu de Castro; Lopes, Jefferson Marcio Sanches; Patrocínio, Antônio Otávio de ToledoThe photophysical characterization allows the assessment of processes following the phenomenon of light absorption, which is of interest for various applications, both in the field of materials chemistry and in photomedicine. This work aimed at the photophysical characterization of potential porphyrinic photosensitizers and their interaction with biomolecular systems and nanostructures. To achieve this, the spectroscopic techniques of Transient Absorption (or Laser Flash-Photolysis) and a Spectrophosphorimeter were implemented, and their usage protocols were established. With these techniques in operation, an alternative method for determining the triplet state formation yield and obtaining the singlet oxygen formation yield was proposed, fundamental properties for the characterization of photosensitizers. It was possible to investigate the interaction of water-soluble porphyrins with bovine serum albumin and verify that this interaction affects the triplet states lifetimes and singlet oxygen yields. These parameters were strongly influenced by the presence of oxygen and the porphyrin's location at the interaction sites in the protein structure. Another study conducted was the interaction of cationic porphyrins with manganese ferrite (FeMn2O4) anionic ferrofluids in which the interaction leads to the suppression of fluorescence and singlet oxygen (1O2) generation of the photosensitizers. Interestingly, this interaction is not predominantly governed by electrostatic interactions but mainly through chemsorptives and physisorptives interactions. Additionally, it was demonstrated that photothermal heating breaks the interaction with the nanostructure, restoring the photophysical properties of the photosensitizer, making this system a multifunctional nanostructure with luminescent and theranostics properties.Item Calixarenos como plataforma de luminóforos e de co-cristalização com nutracêuticos(Universidade Federal de Goiás, 2024-08-15) Alvarenga, Meiry Edivirges; Martins, Felipe Terra; http://lattes.cnpq.br/0466799995060671; Martins, Felipe Terra; Gomes, Danielle Cangussu De Castro; Doriguetto, Antonio Carlos; Araújo Neto, João Honorato de; Santos Júnior, Sauli DosCalixarenes are notable macrocyclic compounds characterized by a variable number of phenolic units linked by methylene bridges. They possess a series of advantageous features, making them an ideal choice for diverse applications. Their ease of large-scale production from low-cost precursors, coupled with their chemical and thermal stability, as well as the ease of functionalization, elevate calixarenes to the status of highly versatile platforms. They can be utilized in the development of a broad range of materials with potential applications in technological and pharmacological areas. Based on the host-guest properties of calixarenes and the high efficiency of aminopyrazine as a blue light emitter, this research focused on the investigation of two calixarene-pyrazinamide hybrids. The primary goal was to combine hosting capabilities and light emission in a single molecular structure. Two compounds yielded three luminescent crystalline forms, whose structures and optical properties could be correlated. One of them crystallized in two forms, non-solvated and a DMF solvate, while the other, without t-butyl substitutions, formed three conformers with DMF. Variations in molecular substitution affected the conformation of the structures, influencing the coplanarity and conformational profile of the phenolic rings. Under an excitation of 388 nm, both emitted light in the 400-550 nm range, peaking at around 500 nm, but with low quantum efficiency. The low efficiency was attributed to the presence of DMF and π...π stacking interactions. Another aim of this research was to explore the use of calix[4]tube in forming cocrystals with resveratrol, an active nutraceutical known for its potential antibacterial, antioxidant, antiinflammatory, and anticarcinogenic benefits, yet with low aqueous solubility. This work represents the first successful attempt to form a neutral-state resveratrol cocrystal, doubling its water solubility. In summary, this study signifies a significant advancement in using calixarenes as molecular bases for luminophores and in the crystallization of the nutraceutical resveratrol. The employed process proved commercially viable, underlining the immense potential of these methods for future applications in technological and pharmaceutical fields. Therefore, the research focuses on the synthesis of calixarene hybrids with light-emitting properties and the development of cocrystals to enhance the solubility of pharmaceutical compounds, demonstrating the versatility of calixarenes in various areas of chemistry.Item Sistemas eletroquímicos - novas abordagens para detecção simultânea e aplicações vestíveis(Universidade Federal de Goiás, 2024-08-30) Romanholo, Pedro Victor Valadares; Sgobbi, Lívia Flório; http://lattes.cnpq.br/0051559038460460; Sgobbi, Lívia Flório; Martins, Paulo Roberto; Jost, Cristiane Luísa; Galli, Andressa; Madurro, João MarcosThis work presents the fabrication methods and the application of two electrochemical systems. The frst one, named yin-yang method, comprises the development of a novel approach for the simultaneous detection of two solvent incompatible molecules, ascorbic acid (vitamin C), and cholecalciferol (vitamin D3). For that end, two electrochemical cells were arranged in a parallel array, resulting in an analytical method capable of simultaneously measuring the output signal of both analytes in a single run. The main goal of this method lies on the possibility of bypassing the analytical limitations present when both analytes are prepared in a single medium, since vitamin C is readily soluble in water but vitamin D3 hardly solubilizes in the same concentration range. Due to the solubilization impairment, the electrochemical output presents with low resolution when both vitamins are collectively analyzed in a single medium, which also impacts the detection since the electrochemical potential shifts considerably. Results showed that the yin-yang method is reliable, may avoid the use of multichannel potentiostats, and might improve analytical parameters. The second system is presented as a wearable paper-based electrochemical platform employed for the continuous monitoring of sweat glucose levels. The device is fabricated with an iontophoretic stage through which sweat stimulating molecules are delivered across the skin to achieve higher fuid fow-rate, while also employing polyacrylamide gels capable of enhancing osmotic pressure to further increase sweat production. The sensor operates by wicking the biofuid directly from skin through a paper patch, which works as substrate for a glucose oxidase modifed electrode to detect changing levels of glucose. Results showed that the device allows the use for extended periods of time by an individual, displaying matching behavior with that of commercial devices. The output signal stability and resolution are shown to be fow-rate dependent and are infuenced by the individual sweat production profleItem Propriedades fotofísicas de filmes multicamadas de perovskita livre de chumbo e compostos eletroluminescentes(Universidade Federal de Goiás, 2024-07-26) Silva, Ramon Miranda; Almeida, Tatiana Duque Martins Ertner de; http://lattes.cnpq.br/9082478597898534; Almeida, Tatiana Duque Martins Ertner de; Colmati Júnior, Flávio; Barbosa, Martin Schwellberger; Talhavini, Márcio; Zalloum, Neife LilianLuminescent organic compounds play an essential role in the fabrication of photosensitive active layers, spanning a variety of applications from sensors to lightemitting diodes, photovoltaic systems, among others. In this context, we explored the creation of multilayer films from a hybrid Perovskite (P), with the configuration CH3NH3SnIxCl3-X, combined with recognized electroluminescent compounds such as Rubrene (R), and the polymer Poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], MEH-PPV (M), which were deposited by the Layer-by-Layer and spin-coating techniques, and their photophysical properties were studied. Using steady-state and time-resolved fluorescence spectroscopy, it was possible to evaluate the optimal conditions for the production of thin films of the isolated compounds and combinations of interest (bi- and trilayers - P/M; P/R; P/M/R and P/R/M), as well as their photophysical properties. Steady-state electronic spectra demonstrated higher efficiency for films prepared from the deposition of layers of perovskite, Rubrene, and MEH-PPV, using solutions with concentrations of 0.6 – 10-5 and 10-8 mol.L-1, respectively. The layer-by-layer technique involved a 90-second immersion, and spincoating films required 100, 40, and 60 seconds of spin-up rotation for perovskite, Rubrene, and MEH-PPV, respectively. Single point and lifetime mapping analyses, using pulsed lasers (373, 452, and 507 nm), indicated tri-exponential behavior in all evaluations. The results showed for P/R layer-by-layer and spin-coating bilayers excited states with greater sensitivity to the excitation wavelength, prolonging lifetimes with decreasing irradiation length. Mapping analysis indicated regions with higher Eficiência de FRET for P/R when excited at 373 and 452 nm, and for P/M at 507 nm excitation. The Single point data of the Trilayers showed that the inversion in the order of deposition of the semiconductors directly influenced the formation of the system's excited states, with the P/M/R film showing greater sensitivity to the photophysical processes as the excitation length varied. and P/R/M greater stability. Mapping indicated higher FRET rates for P/M/R produced by layer-by-layer, which was selected for UV-Vis sensing studiesItem Deciphering the stereoselectivity of Claisen rearrangements: joint density functional theory and machine learning models(Universidade Federal de Goiás, 2024-01-29) Oliveira, Ana Gabriela Coelho; Oliveira, Heibbe Cristhian Benedito de; http://lattes.cnpq.br/ 5995553993631378; Oliveira, Heibbe Cristhian Benedito de; Alonso, Christian Gonçalves; Muniz, Aline Silva; Silveira Neto, Brenno Amaro da; Oliveira, Guilherme Colherinhas deIn the present study, the stereoselectivity of Claisen Rearrangements was addressed, focusing on the influence of two distinct electron-withdrawing groups and eight different substituents in three variants of the rearrangement: Hurd, Eschenmoser, and Johnson. Using the Curtin-Hammett principle, the energies of reactions, products, and transition states were calculated using the M062X/def2TZVPP theory level. The results indicate that kinetic effects predominantly govern the reaction equilibrium. A key aspect of our investigation involved applying Shubin’s energy decomposition analysis to the optimized transition states. This approach highlighted the significant influence of the electrostatic component on stereoselectivity, revealing its predominance over the quantum and steric components. Moreover, each transition state was divided into four fragments: the electron-withdrawing groups (Ester and Nitrile), the specific Hurd/Esch/John group (H, NMe2, and OEt), various substituents (alkyl and aryl), and the central fragment. This fragmentation allowed for a comprehensive analysis of the dipole moments of the groups and non-covalent interactions, providing insights into the electrostatic forces driving the rearrangement process. In addition, Supervised Machine Learning algorithms were employed, focusing on the analysis of electronic and geometric datasets related to the transition states. The results obtained not only elucidate the mechanisms underlying the stereoselectivity of Claisen Rearrangements but also provide a subtle understanding of the interaction between different molecular components, establishing new perspectives in advanced applications in organic synthesis.Item Estudo de degradação forçada e de compatibilidade do ciprofibrato com excipientes farmacêuticos(Universidade Federal de Goiás, 2022-08-31) Brito, Camila Cíntia Sousa Melo; Leles, Maria Inês Gonçalves; http://lattes.cnpq.br/1614912440064013; Leles, Maria Inês Gonçalves; Siqueira, Adriano Buzutti de; Chaves, Andrea Rodrigues; Ionashiro, Elias Yuki; Ribeiro, Elton BritoCiprofibrate-CPF is a hypolipidemic that promotes the reduction of serum levels of cholesterol and triglycerides by stimulating activated nuclear receptors for peroxisome proliferation-alpha-PPAR-α. In this work, the stability of CPF was studied using forced degradation and compatibility studies. The Active Pharmaceutical Ingredient-API (SQC) was characterized by Thermogravimetric Analysis/Derivative Thermogravimetric AnalysisTGA/DTGA, Differrential Scanning Calorimetry-DSC, Differrential Scanning Calorimetry coupled to the Photovisual system-DSC-Photovisual, Absorption spectroscopy in the mid-infrared region with Fourier Transform-FTIR, Nuclear Magnetic Resonance-RMN, Powder X-ray Diffractometry-DRXP, High Resolution Mass Spectrometry-EMAR and High Performance Liquid Chromatography coupled with Diode Array Detector and High Resolution Mass Spectrometry-CLAE/DAD/EMAR. The forced degradation study was carried out for CPF (SQC) under the following conditions: acid hydrolysis, basic hydrolysis, oxidative and thermal at 70 °C 240 hours using EMAR and CLAE/DAD/EMAR. The compatibility study between the CPF and the excipients was carried out by preparing binary mixtures in the proportions 50:50 and 92:08 (m/m), where the isolated components (CPF (SQT) and excipients), Simulated Excipients Sample-ASE (excipients) and the binary mixtures (CPF-excipient or CPF-excipients) were analyzed by TGA/DTGA, DSC, DSC-Photovisual, FTIR, and DRXP. The EMAR and CLAE/DAD/EMAR results suggested the degradation of CPF when subjected to basic hydrolysis, with some degradation products previously reported in the literature being observed and a new product identified. In the other exposure conditions, the CPF remained stable. The DSC technique suggested signs of interaction between the CPF and the excipients (Sodium Starch Glycolate-AGS, Sodium Lauryl Sulfate-LSS, Silicon Dioxide-DOS and Hydrogenated Vegetable OilOVH) when prepared in a proportion 50:50 (m/m) and between CPF and the excipient (OVH) in a proportion (92:08 m /m). However, the FTIR and DRXP techniques did not confirm the sings of interaction observed in the DSC, except when DOS was used at 50%. The compatibility study indicated the use of the CPF-ASE binary mixture in the proportion 50:50 (m/m) as a candidate for pre-formulation.