http://hdl.handle.net/10256/10232 2025-08-08T03:44:08Z http://hdl.handle.net/10256/26674 Optimització de sistemes basats en nanopartícules de sílice per a la catàlisi heterogènia d’acoblament d’alcohols Linillos Morgado, Ruth In this final degree project, ruthenium complexes based on polypyridyl and dmso ligands have been synthesized and characterized, with the aim of evaluating their catalytic activity in the coupling of alcohols and the possibility of anchoring silica nanoparticles in these types of complexes in order to optimize the system. These compounds have been obtained from a first synthesis of the compound [RuCl2(dmso)4, [1], from the reagent RuCl3·3H2O and dimethylsulfoxide at reflux. Once this complex has been obtained, a second synthesis is carried out where the 2,2':6',6"-terpyridine ligand is coordinated to the compound [1] in chloroform at 80oC, to end up forming cis-[RuCl2(terpy)(dmso), [2]. In order to study and characterize the properties of the synthesized compounds, spectroscopic (NMR, UV-vis), spectrometric (ESI-MS) and electrochemical (cyclic voltammetry) techniques have been used. On the other hand, in this work, studies have been carried out focused on the incorporation of the compounds into different silica materials (ST, LUS-TMA o-Ph-ST and Ph@LUS), some of them, of the nanoparticle type, with the aim of making the catalytic system more efficient. As in the previous study, spectroscopic (NMR, UV-vis), spectrometric (ESI-MS) and electrochemical (cyclic voltammetry) techniques have been used to to characterize the new materials generated. In addition, the catalytic efficiency of the complexes has been evaluated in the coupling of benzyl alcohol and 1-phenylethanol in homogeneous phase, using several bases (potassium hydroxide, potassium carbonate, piperidine and sodium methoxide) to improve selectivity and conversion. Of these bases, the most suitable has been sodium methoxide. Additionally, the coupling product has been quantified by gas chromatography using biphenyl as an internal standard, and the percentage of conversion and selectivity of the different complexes have been calculated to be able to compare the catalytic activity of the complexes in catalysis. The catalytic activity of the heterogeneous systems obtained from anchoring the catalysts on silica-type supports has also been studied, but the activity obtained has been low. At the end of the work, future strategies are proposed to improve the efficiency of heterogeneous catalysts 2025-02-01T00:00:00Z http://hdl.handle.net/10256/26266 Estudi de l’aromaticitat en l’estat singlet i triplet de compostos de bifenilè fusionats amb anells de sis membres Vidal Sabench, Maria π-Conjugated compounds formed by fused cycles with 4n+2 and 4n π electrons are interesting for understanding the limits of aromaticity and antiaromaticity. These compounds in the ground state exhibit intermediate properties between aromatic and antiaromatic systems. However, their behaviour in the triplet state is not fully understood. This study explores the rules of aromaticity, specifically Hückel’s and Baird’s rules, along with Clar's π-sextet theory. The research combines these rules to investigate the triplet state energy of 25 molecules, which are composed of biphenylene compounds fused with six-membered rings, using density functional theory (DFT) calculations performed with the Gaussian16 program. To determine the aromaticity of the molecules, the NICS index has been analysed to identify the presence of diatropic currents, indicative of aromaticity, and paratropic currents, indicative of antiaromaticity, within the rings of the molecules. Spin density has also been used to locate unpaired electrons. The results indicate that molecules with the highest number of Baird rings combined with closedshell Clar π-sextets, with all electrons paired, are particularly stable in the triplet state. However, steric effects can increase the energy of the molecules, decreasing their aromatic stability in both electronic states. Additionally, the Radenkovic model used to predict triplet state energies has been validated, and Leyva-Parra's theory has been applied to analyse how the antiaromatic character of the central ring in the ground singlet state influences the energy difference between the singlet (S0) and triplet (T1) states. In conclusion, this work demonstrates that the combined use of Baird and Clar's rules can help to better understand the behaviour of compounds containing rings with 4n and 4n+2 π electrons in their different electronic states, significantly contributing to the theoretical chemistry of aromatic and antiaromatic compounds 2024-07-01T00:00:00Z http://hdl.handle.net/10256/26265 Avaluació de la capacitat de tractaments terciaris d’aigües residuals basats en Daphnia magna per filtrar nanopartícules metàl·liques en condicions controlades i en presència de microplàstics : estudis de laboratori Garcia Metje, Clàudia At present, the increase in the nanotechnology industry has led to a rise in the use of nanoparticles (NPs). These have very interesting properties that allow for applications in different sectors, such as medical, technological, and energy. In this case, we will focus the study on silver nanoparticles (AgNPs), highly used in the medical industry thanks to their antibacterial properties, and titanium oxide nanoparticles (TiO2NPs), with important applications in daily consumer products. These nanoparticles, like microplastics, accumulate excessively in ecosystems, causing a negative effect on the life forms present in them. Regarding the 1960s and 1970s, the mass use of plastics experienced significant expansion due to the increased production of plastic products. As a result, ecosystems have suffered an uncontrolled rise in waste, leading to the accumulation of MP, negatively affecting the fauna and flora of the ecosystems. This study examines the effect of NPs and MPs in the presence of Daphnia magna (D. magna). D. magna is a small crustacean capable of ingesting or eliminating small particles that do not precipitate in secondary sedimentation tanks. For this reason, laboratory studies are conducted to simultaneously assess the toxicity of NPs and the presence of MP in D. magna, as well as to determine the metal absorption capacity of these organisms. AgNPs, TiO2NPs, and polyethylene MP were used in the various experiments. Studies were conducted on the stability of NPs in different concentrations of humic acids and surfactants, as well as working with NPs of different sizes and coatings to determine their behavior and evaluate the effect caused by the presence of D. magna. First, it was determined that D. magna is capable of surviving for a certain period under stress conditions and assimilating some of the present metal. It is important that the presence of MP negatively affects survival. Additionally, glass wool was established as the most adequate filtration method among those evaluated for nanoparticle suspensions. Finally, in scanning electron microscope (SEM) studies, the presence of AgNPs in the solutions was verified after 72 hours under typical laboratory conditions and in the presence of light, although they appear to be aggregated. As for TiO2NPs, it was found that after 72 hours, there are no nanoparticles present, corroborating previous results obtained by ICP-MS, where a similar behavior between ionic titanium and TiO2NPs was observed 2024-07-01T00:00:00Z http://hdl.handle.net/10256/26264 Avaluació de l’eficiència de sistemes de tractament terciaris basats en la natura : eliminació de contaminants emergents Sorroche Bonet, Judith 2024-07-01T00:00:00Z