Antigo Programa de Pós-Graduação Interdisciplinar de Biociências Aplicadas http://bdtd.uftm.edu.br/handle/tede/993 2026-11-06T16:09:31Z 2026-11-06T16:09:31Z http://bdtd.uftm.edu.br/handle/123456789/2183 2026-11-04T02:02:59Z 2026-02-10T00:00:00Z

Título: Síntese e caracterização de nanocristais de perovskita de CsPbI 3 dopados com cobalto Abstract: Perovskites can be formed by different combinations of chemical elements, resulting in a wide variety of structures. This structural diversity allows the production of compounds with distinct physical properties, such as ferroelectricity and pyroelectricity. Thus, the present work aims to synthesize and characterize cobalt-doped CsPbI₃ nanocrystals using the melt method. Doping with divalent metal ions has been considered an effective approach to improve external quantum efficiency due to its effect on reducing non-radiative recombination, lowering charge injection barriers, and enhancing charge carrier transport properties. Moreover, the microstructure and optical properties of the perovskite nanocrystals were characterized by Transmission Electron Microscopy, X-ray Diffraction, UV–Vis–NIR Optical Absorption Spectroscopy, and Photoluminescence. Currently, the literature reports studies on perovskites aimed at optical and electronic applications, with the vast majority focused on ABX₃ perovskites, where X generally belongs to the halogen group or corresponds to the O anion (oxygen), forming ABO₃ compounds. Therefore, in this work, a dopant strategy was developed to elucidate the internal mechanism of Co²⁺ doping, to determine its impact on the structure and properties of CsPbI₃ perovskite quantum dots, and to analyze their performance for optoelectronic applications. Finally, the authors acknowledge the Coordination for the Improvement of Higher Education Personnel (CAPES) for the financial support provided for this research, which was essential for the development of the experimental activities and for obtaining the results presented. Tipo: Dissertação

2026-02-10T00:00:00Z http://bdtd.uftm.edu.br/handle/123456789/2134 2026-09-17T02:03:24Z 2026-07-14T00:00:00Z

Título: Desenvolvimento de complexos de Pd(II) e Pt(II) a partir da diacetilmonoxima tiossemicarbazona: síntese e elucidação estrutural Abstract: Thiosemicarbazones constitute an important class of ligands due to their high structural versatility and the diverse biological properties associated with their metal complexes. In particular, PdII and PtII complexes containing these ligands have attracted considerable interest as potential metallodrugs, since modifications in the coordination sphere can directly influence their structural, electronic, and chemical properties. In this context, the present study aimed to synthesize and characterize new PdII and PtII complexes containing a diacetyl monoxime-derived thiosemicarbazone, as well as to investigate the influence of replacing the fourth coordination site with different phosphine ligands and the effect of the solvent employed during the syntheses. Initially, the ligand H₂DMTSC was synthesized, followed by the preparation of complexes of the type [M(HL)X] (M = PdII and PtII; X = Cl- and I-). Subsequently, complexes containing the phosphines 1,3,5-triaza-7-phosphaadamantane (PTA) and tris(diethylamino)phosphine (TDA) were synthesized to afford complexes of the type [M(HL)(PR₃)]. The compounds were characterized by infrared and UV–Vis spectroscopy, 1H and 31P nuclear magnetic resonance spectroscopy, high-resolution electrospray ionization mass spectrometry, and single-crystal X-ray diffraction. The results confirmed the tridentate coordination mode of the thiosemicarbazone ligand and demonstrated that substitution at the fourth coordination site promotes significant changes in the spectroscopic properties of the complexes. Furthermore, it was demonstrated that the use of methanol as the reaction solvent promotes the replacement of the diethylamino groups of TDA by methoxy groups, leading to the formation of complexes containing P(OMe)₃ instead of P(NEt₂)₃. This transformation occurs only after complexation, highlighting the influence of both the metal center and the solvent on the final composition of the products. The results demonstrated that the [MCl(HL)] complexes can be employed as versatile precursors for the synthesis of new complexes through modification of the fourth coordination site and that, depending on the phosphine employed, the reaction solvent may influence the final composition of the species formed. Overall, these findings contribute to a better understanding of the reactivity of these systems, providing valuable insights for the development of new synthetic strategies and the preparation of compounds with potential antitumor activity. Tipo: Dissertação

2026-07-14T00:00:00Z http://bdtd.uftm.edu.br/handle/123456789/2124 2026-09-14T15:50:45Z 2026-04-24T00:00:00Z

Título: Caracterização do bioativo natural paepalantina encapsulada em lipossomas unilamelares grandes - LUVs Abstract: Bioactive compounds have garnered significant attention due to their wide range of biological activities and their applicability in the food, cosmetic, and pharmaceutical industries. Among these compounds, paepalantine stands out for its well-documented anti-inflammatory, antioxidant, and anticancer properties. However, its therapeutic potential is limited by unfavorable physicochemical characteristics, including low aqueous solubility, high susceptibility to environmental degradation, and reduced stability in the gastrointestinal tract factors that compromise its bioavailability and pharmaceutical applicability. To address these limitations, nanoencapsulation emerges as a promising strategy to enhance the stability and performance of paepalantine in biological systems. In this context, the present study aimed to characterize the interaction of paepalantine with liposomal systems, evaluating key physicochemical parameters essential for the development of nanoformulations. Spectrophotometric analyses revealed changes in the compound’s absorption profile following incorporation into lipid matrices, indicating a strong affinity for hydrophobic environments. Multilamellar liposomal formulations exhibited adequate stability, as demonstrated by hydrodynamic size and zeta potential measurements, reinforcing the feasibility of employing liposomal systems for paepalantine encapsulation. The results presented here expand current knowledge regarding the behavior of paepalantine in lipid systems and provide fundamental parameters for future nanoencapsulation approaches and the development of more efficient pharmaceutical formulations. This study contributes to the scientific understanding of paepalantine’s applicability and establishes a solid methodological foundation for subsequent investigations. Thus, it is possible to highlight that the characterization performed demonstrates the potential of paepalantine for the development of nanostructured systems applicable to the pharmaceutical field. Tipo: Dissertação

2026-04-24T00:00:00Z http://bdtd.uftm.edu.br/handle/123456789/2108 2026-09-14T15:51:12Z 2017-08-31T00:00:00Z

Título: Preparação de particulados de celulose de fibra de bananeira carboximetilada visando estudos de liberação prolongada de fármaco Abstract: Systems of drug release made of cellulose obtained from renewable sources have been widely used in several works. In this context, this project aimed to produce micro particulates from the cellulose extracted from the banana pseudo stem fibers. In order to evaluate the quality of the cellulosic fiber obtained, some characterizations were performed, in which the banana pseudo stem fibers presented 10.12% of total extractive, 37.55% of cellulose and 26.68 % of hemicelluloses. Total lignin content was 13.66%. After the use of 3% sodium hydroxide solution, it was obtained treated fibers (FT) with a Kappa number value of 5.34. The micro Kappa number was 0.17 in the bleached treated fibers (FTB), which indicates that the lignin was practically removed. The crystallinity indexes for crude fiber (FB), FT and FTB were 44%, 45% and 65% respectively, evidencing that the removal of non-cellulosic components is responsible for the observed index increase. The particulates produced from the carboxymethylation of the FTB by the method of biomineralization were almost spherical, with dimensions varying from 1μm to 5μm, which were measured by scanning electron microscopy. The thermogravimetry and derivative thermogravimetry showed that the removal of non-cellulosic components of the banana pseudo stem fibers altered the thermal stability of the fibers, since the FB, FT, and FTB presented maximum decomposition temperatures (TMÁX) of 304, 353 and 340 ºC, respectively. The carboxymethylcellulose (CMC), CMC/CaCO3 (100) and CMC/CaCO3 (50) had maximum decomposition temperatures (TMÁX) of 261, 288 and 291 ºC, respectively. This result evidenced that the presence of the inorganic complexant increased the thermal stability of the synthesized particulates. In the kinetic study of release of thiamine hydrochloride, performed in buffer solution pH = 6.5, the load of inorganic complexant used during the synthesis of the particles affects the release kinetics, as seen by the kinetic constants K1 and K2 which are involved in the two release steps, according to the Korsmeyer-Peppas model. Furthemore, the kinetic study of the release of thiamine hydrochloride showed that the CMC particulate system of the banana pseudo stem fibers present a good potential to be explored. Tipo: Dissertação

2017-08-31T00:00:00Z