Treballs Finals de Grau (TFG) - Química

URI permanent per a aquesta col·leccióhttps://hdl.handle.net/2445/48525

Treballs Finals del Grau de Química de la Facultat de Química de la Universitat de Barcelona.

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Synthesis and kinetics of photoisomerization processes of water soluble Pt(II) compounds
(2028-06) Valenzuela Gimeno, Neus; Ferrer García, Montserrat
This study focuses on the synthesis of water-soluble square-planar Pt(II) complexes containing the azobenzene ligand 4-phenylazopyridine (Phpy) via substitution reactions from a Pt(II) diamine (TMEDA) precursor. The aim of this work is to investigate the cis-trans isomerization mechanism of the azobenzene coordinated to the metal center, with the goal of achieving a deeper understanding of this process. A comprehensive study aimed at the synthesis of [Pt(Phpy)2TMEDA]2+ was carried out. Initial attempts employed [Pt(H2O)2TMEDA](OTf)2 as a building block; however, no reaction was observed. The Pt(II) precursor was subsequently replaced with the literature reported “[Pt(NO3)2TMEDA]” complex. It was found that the nitrate building block was not well characterized in the literature and the synthesis described led to the dinuclear complex [Pt2(OH)2TMEDA2](NO3)2 instead. Nevertheless, the latter compound did not allow the obtention of the desired azoderivative. Thus, a different precursor was selected [Pt(MeCN)2TMEDA](OTf)2. After a study to optimize the reaction conditions, the bisazo complex [Pt(Phpy)2TMEDA](OTf)2 was successfully isolated and fully characterized. Furthermore, later studies enabled the obtention of the monoazo analogue [Pt(MeCN)(Phpy)TMEDA](OTf)2. A brief investigation under the same reaction conditions was carried out using different azobenzenes bearing appended isocyanide moieties to evaluate whether this synthetic approach could be extended to other ligands. However, these attempts did not afford the targeted products. Once the desired products were obtained, a kinetico-mechanistic study of the thermal cis-trans isomerization in different solvents of the coordinate azobenzene ligands was carried out. The corresponding activation parameters were determined, and a mechanism of isomerization proposed. The availability of both mono- and bisazo complexes allowed the investigation of the existence of cooperative effects, which to date have not been unambiguously demonstrated in square-planar platinum(II) complexes containing two azobenzene ligands in cis position.
Molecular metal oxide-base materials for electrooxidation of Glycerol (GOR)
(2026-06) Torrens Fabregat, Aina; Pascual Borràs, Magda
The growing need for sustainable systems has intensified interest in green hydrogen as a fuel. Although water electrolysis is a promising route, its efficiency is limited due to the oxygen evolution reaction at the anode. To address this issue, the development of an efficient and earth-abundant electrocatalyst is essential. In parallel, replacing the OER with the oxidation of small organic molecules, in this case glycerol, an abundant byproduct, offers an attractive strategy to reduce the energy consumption needed while generating high value chemicals. This study focuses on the synthesis, characterization and electrocatalytic evaluation of three heterometal-substitute polyoxometalates (POMs): two Lindqvist dimers and one Keggin-type POM incorporating cobalt or iron. The aim of this project is to understand how both the POM structural framework and the identity of the incorporated metal centre influence catalytic activity in the oxygen evolution reaction (OER) and glycerol oxidation reaction (GOR). These studies represent new contribution for both POM families, as the electrocatalytic behaviour of Lindqvist structures in OER and GOR has not been reported, and the Keggin structure has not yet been explored for GOR. Only a limited number of studies exist on POMs as active catalysts for glycerol oxidation coupled with the hydrogen evolution reaction (HER). The parent tungstate Lindqvist cluster, (TBA)2[W6O19], was synthesised through both acidic and basic routes and subsequently transformed into cobalt- and iron- substituted dimers. In parallel, lacunary Keggin precursors were also synthesized, characterized and used to obtain the cobalt-substituted Keggin structure. All compounds were characterized by infrared spectrometry, cyclic voltammetry, electrospray ionization mass spectrometry and NMR spectrometry to confirm the successful synthesis and metal incorporation. The electrochemical studies reveal a clear structure-activity relationship: the Co-Keggin complex shows the highest catalytic activity for both OER and GOR, followed by the Co-Lindqvist dimer, while the Fe-Lindqvist analogue show the lowest performance. Product analysis of the GOR by 1H NMR confirms the oxidation of glycerol through the formation of dihydroxyacetone and formic acid. Despite the confirmed electrocatalytic activity, all three POMs exhibit relatively low current densities, showing they are not strong candidates for practical OER or GOR applications when working on their own, where higher activity and robustness are required. Overall, this study provides a systematic comparison of structure, stability, and catalytic behaviour in Co- and Fe-substituted POMs, highlighting the superior performance of the Keggin framework and the key role of cobalt in oxidative electrocatalysis, while also underscoring the limitations that prevent these systems from being competitive electrocatalysts.
New 2D perovskites with an additional H-bonding in the organic sublattice for renewable energy storage
(2026-06) Santos Irulegui, Julia; Matheu Montserrat, Roc
The transition towards an energy model based on renewable sources requires efficient solutions for storing and managing energy in a sustainable manner. In this context, Thermal Energy Storage (TES) emerges as a key technology for storing excess energy from renewable sources and improving the efficiency of industrial processes. Industrial activity is highly energy-intensive and generates large amounts of waste heat from equipment such as furnaces, boilers, and turbines. The recovery and reuse of this heat through TES systems contributes to reducing fossil fuel consumption and associated emissions. Within this framework, solid–solid Phase Change Materials (PCMs) with high latent heat in the intermediate temperature range (100–220 °C) are particularly attractive candidates, as they enable the safe and efficient storage of thermal energy without leakage issues. Among these materials, two-dimensional (2D) hybrid halide perovskites (A2BX4) stand out due to their remarkable chemical versatility, which allows their thermal properties to be finely tuned according to the requirements of specific energy applications. In this work, we report the synthesis of a new series of copper-based 2D perovskites functionalized with aminoalkanoic acids to introduce additional hydrogen-bonding networks. The compounds [COOH-Cn]2CuCl4 and [COOH-Cn]2CuBr4 (n = 5, 7, 9, and 11) were prepared and structurally characterized, including single-crystal X-ray diffraction analysis of [COOH-C11]2CuCl4. Differential scanning calorimetry revealed a high latent heat value of 66 J g⁻¹ at 145 °C for [COOH-C11]2CuCl4, highlighting its potential as an advanced material for sustainable thermal energy storage systems aimed at waste heat recovery and the efficient integration of renewable energy sources.
Computational study of Organic Magnetism in Triangulene-Based Diradicals through pi-Conjugated Linker design
(2026-06) Rozalén Millán, Àlex; Ribas Ariño, Jordi; Bromley, Stefan Thomas
This work presents a computational study of organic magnetism in triangulene-based diradicals connected through π-conjugated organic linkers. The main objective is to identify structural and electronic factors that favour the stabilization of high-spin states and enhance ferromagnetic coupling between two persistent radical centers. Density Functional Theory calculations were performed to evaluate different linker structures, substitution patterns and radical-linker connections. The magnetic behaviour was analysed using the singlet-triplet energy difference, defined as ΔES-T = ESinglet - ETriplet, as a comparative descriptor of triplet-state stabilization. The results show that the linker plays an active role in the magnetic communication pathway, rather than acting only as a passive spacer between the radical units. Cyano-substituted non-Kekulé linkers were first investigated, showing that electron-withdrawing groups strongly influence the stabilization of the triplet state. Among the systems studied, the disubstituted linker was selected as a suitable compromise between ferromagnetic coupling and synthetic feasibility. The effect of additional substituents was also analysed, revealing that halogen substitution, especially fluorine, increases the singlet-triplet energy difference, whereas electron-donating groups such as hydroxyl and amino groups lead to lower values. Frontier orbital analysis showed that favourable alignment and spatial similarity between the linker LUMO and the triangulene SOMO promote spin delocalization through the π-conjugated bridge. The influence of the radical–linker distance was studied by comparing direct connections with acetylene and diacetylene spacers. Although shorter connections generally provide stronger coupling, acetylene-based bridges remain attractive due to their linear geometry and synthetic accessibility. Finally, carboxylic acid groups were explored as promising alternatives to cyano substituents. These systems retain significant triplet stabilization and show a strong dependence on the orientation of the COOH group, suggesting that local polarization and weak intramolecular interactions may provide additional ways to tune magnetic coupling. Overall, this work provides useful structure-property relationships for the rational design of future high-spin organic materials with potential applications in molecular electronics, spintronics and organic magnetism.
Assessement of the σ-donation of phosphorus ligands through the study of the published 1JPSe
(2026-06) Ríos García, Dakota; Grabulosa, Arnald
Phosphorus(III) ligands (PR3) are central to homogeneous catalysis, to the point of underpinning several Nobel Prizes in Chemistry. Their importance lies in the fact that, upon coordination to the metal, they control the electron density and the steric environment of the metal centre and thereby govern the key steps of the catalytic cycle, giving rise to levels of activity and selectivity unattainable by other means. This control is possible thanks to their dual σ-donor and π-acceptor character, a delicate balance that can be finely tuned by modifying the groups bonded to the phosphorus. Such tunability is at their greatest advantage and the reason why measuring their σ-donor strength is worth to understand their electronic properties. One of the most practical tools for assessing this property is Nuclear Magnetic Resonance (NMR) spectroscopy. When a phosphane (PR3) is converted into its selenide (Se=PR3), the one-bond coupling constant ¹JPSe reflects the s-character of the phosphorus lone pair through the Fermi-contact term. In accordance with Bent's rule, this value decreases when the substituents are good electron donors and increases when they are electron-withdrawing. Although ¹JPSe values have been determined for several thousands of compounds, these data had never been compiled or analysed collectively. The present work addresses this gap through a systematic literature search in SciFinder and Reaxys, complemented by cited reference searching of the seminal papers on the topic. As a result, in this TFG 1250 publications reporting ¹JPSe values have been identified and collected. All the documentation was managed with EndNote, and, from a representative sample of 250 articles, the relevant information was organised in an Excel workbook structured into separate sheets according to ligand type. For each compound, the SMILES code, the ³¹P chemical shift, the ¹JPSe value and the experimental measurement conditions were recorded, which made it possible to classify the ligands according to the atoms directly bonded to phosphorus and to compare them across different families. The analysis of the data reveals two important facts. Firstly, the solvent appreciably influences the value of the coupling constant, so comparisons were restricted to data in similar solvents. Secondly, the nature of the atoms bonded to phosphorus determines a clear trend in the ¹JPSe values, consistent with the differences in electronegativity between the substituents. These findings confirm the value of phosphane selenides as simple model systems and of the ¹JPSe constant as a reliable NMR descriptor for ranking σ-donor ability within structurally related ligand families. The work also delivers an expandable database that may prove useful for the study, parametrisation and rational design of new phosphorus ligands
Determination of acidity constants of low solubility compounds by potentiometry and capillary electrophoresis.
(2026-06) Moneo Boixadera, Maria; Fuguet i Jordà, Elisabet; Fernández Pumarega, Alejandro
The determination of acidity constants (pKa) is essential in drug discovery and pharmaceutical analysis because many drug candidates possess acid-base properties, and their ionization state strongly influences their physicochemical properties such as absorption, distribution and excretion. However, such compounds usually exhibit poor aqueous solubility, making pKa determination in hydro-organic media necessary. In this work, potentiometric titration and the internal standard capillary electrophoresis method (IS-CE) were applied to study determine pKa and pH in different hydro-organic solvent mixtures. Firstly, potentiometric determinations were carried out to establish reliable reference pKa values for several acidic and basic compounds in acetonitrile-water mixtures containing between 0% to 90% of organic solvent. The results showed that for acidic compounds, pKa values increased progressively when increasing the acetonitrile content, while bases exhibit a decrease in the values up to 70% of acetonitrile, followed by an increase at higher organic solvent proportions. These trends are consistent the relative permittivity, the basicity of the solvent and the specific solvation effects. Reliable potentiometric determinations for acids and protonated bases were only possible up to 60% of acetonitrile content because side reactions between the titrant (potassium hydroxide) and the organic solvent prevented accurate measurements. Secondly, the IS-CE method was evaluated for the determination of the pH of ammonium-acetate buffers prepared in different methanol-water mixtures containing between 10 and 90% (V/V) of the organic solvent. The method was applied using internal standards (IS) whose reference pKa values in water-methanol mixtures had previously been established by the research group. The pH values determined by this method showed great agreement with values previously measured for each of the buffers, yielding deviations equal or lower than 0.2 units. Overall, potentiometric results provide reference pKa values of many compounds in acetonitrile-water mixtures, which could help IS-CE method implementation in this media. Furthermore, the results obtained by the IS-CE method in water-methanol mixtures validate it as a fast, accurate and reliable alternative for pH determination in this media.
Optimization of the crosslinker and fluorophore chain length in liquid crystal material mechanoluminiscence
(2026-06) Martínez de la Concepción, Biel; Velasco Castrillo, Dolores
Smart materials, capable of dynamically altering their physical properties in response to external orientation-dependent stimuli, have emerged as highly relevant candidates for advanced technological applications. Within this framework, liquid single crystal elastomers (LSCEs) represent a unique class of responsive networks that combine the cooperative order of liquid crystals with the macromolecular elasticity of polymer networks. This research focuses on the molecular design, processing-dependent configuration and macroscale mechano-optical characterization of functionalized liquid single-crystal elastomers synthesized as responsive mechanofluorescent strain sensors. Chromophores based on functionalized carbazole units with varying alkyl spacer lengths and attachment geometries were integrated as minor emissive tags into a major liquid-crystalline host matrix. The study systematically compares the influence of two film-deposition techniques on the baseline network arrangement and the resulting solid-state luminescence: high-speed centrifugal spin-coating and stationary mould casting. Photophysical evaluations in dilute solution initially revealed that oxygen-linked carbazole monomers, functioning in an end-on layout, possess enhanced quantum efficiencies and a bathochromic shift compared to nitrogen-linked side-on analogues due to the electron-donating nature of the alkoxy chains attached to the carbazole core. Upon polymerization into solid-state films, the bulk matrix introduces a severe inner-filter effect and significant light scattering. To secure high-resolution optical data, photoexcitation conditions were strategically optimized to the absolute absorption maximum of the fluorophore. Under uniaxial tensile strain, the mechanical deformation is directly transduced by the architectural layout of the probe; the linear end-on derivatives align parallel to the host mesogens, where lateral film contraction drives them into tight face-to-face proximity, favouring static π-π stacking and a deep, rapid quenching. On the other hand, the perpendicular side-on pendant architectures undergo mechanical disruption into high local disorder, yielding a more progressive and continuous variation in solid-state emissions. Furthermore, the macromolecular configuration and baseline aggregate constraints were found to be strictly dictated by the fluid dynamics of film processing rather than the specific design of the minor fluorophore fraction. Traditional stationary mould casting traps the network into thick, entangled domains that promote random chromophore aggregation, leading to high baseline self-quenching and the emergence of a prominent intermolecular excited-state complex (exciplex) emission. On the contrary, the high shear rates experienced during centrifugal spin-coating mechanically counteract native aggregation, forcing the network into an ultra-thin planar conformation that maximizes initial spatial separation to preserve clean monomer fluorescence. Volumetric equilibrium swelling experiments in toluene confirmed that while the thermodynamic expansion limits are strictly governed by the bulk matrix and the uniform density of the cross-linking agent, the processing determines network anisotropy. Centrifugal deposition yields highly oriented configurations capable of substantial asymmetric swelling, whereas mould casting restricts solvent diffusion due to isotropic cross-linking constraints. Crucially, the swelling-deswelling cycle acts as an essential purification step that efficiently extracts unreacted monomers from the elastomer. Upon complete drying, the processing history is permanently locked into the network baseline density, where spin-coated frameworks sustain sufficient molecular spacing to prevent self-quenching. Ultimately, this work demonstrates that engineering highly sensitive, tailorable mechanofluorescent LSCE sensors demands a coordinated synergy between the precise spatial layout of the molecular probe and the fluid-dynamic control of the processing method.
Data-Driven Modelling of Electronic Properties in Organic Radicals Using Graph Neural Networks
(2026-06) Marcos Vall, Biel; Heras Domingo, Javier
Organic radicals play a central role in many areas of chemistry, but predicting their electronic properties through quantum chemical calculations remains computationally demanding. This project explores the use of artificial intelligence to address this challenge, focusing on properties related to the stability and electronic structure of organic radicals. To evaluate this strategy, a large-scale dataset containing approximately 246,000 radical and molecules was analysed using both classical molecular descriptors and graph-based representations. Classical molecular representations based on Morgan fingerprints and SOAP descriptors were compared with self-supervised graph representations obtained through the Molecular Contrastive Learning (MolCLR) framework. Different neural network architectures, including local propagation and attention-based models, were also evaluated. The results showed that graph-based representations outperform traditional molecular descriptors for the prediction of electronic properties in organic radicals. MolCLR provided a more effective description of the local chemical environment than classical 2D and 3D descriptors. In addition, hyperparameter optimisation further improved model performance. The resulting model predicted quantum chemical properties at a significantly lower computational cost than DFT calculations. Finally, latent-space analysis and clustering revealed that chemically related radicals are organised into coherent structural families within the learned representation. These findings indicate that graph neural networks not only improve predictive accuracy but also capture chemically relevant information about radical structures. Overall, this work demonstrates that graph-based machine learning methods can provide accurate and computationally efficient alternatives to traditional quantum chemical calculations. It also opens the possibility of predicting EPR-related descriptors directly from molecular structure in future studies.
Development of Ultra-Small Rare-Earth-Doped Cerium Oxide Nanoparticles for Environmental Remediation
(2026-06) Càmara Querol, Arnau; Batlle Gelabert, Xavier; Moya Álvarez, Carlos
Cerium oxide nanoparticles (CeO2) have earned a well-deserved scientific interest due to their exceptional redox flexibility, which arises from the reversible transition between the Ce3+ and Ce4+ oxidation states and the subsequent generation of oxygen vacancies. This work presents the development, characterization, and evaluation of a series of nanomaterials based on CeO2 structurally modified through doping with transition metals (Iron) and rare-earth elements (Erbium) in order to enhance their physicochemical properties. The synthesis of these ultra-small (2-4 nm) nanoparticles (NPs) was carried out using a citrate complexation method via wetchemistry routes. Transmission electron microscopy (TEM) revealed the high crystallinity and homogeneous composition of the samples across almost all doping levels. From the analysis of the high-resolution images, it could be determined that the lattice fringes corresponded to the d-spacing values of the CeO2 FCC (Face-Centred Cubic) structure. Dynamic Light Scattering results were in line with the results obtained from TEM and confirmed no aggregation phenomena as particles remained stable in water media thanks to citrate functionalization. The peaks gathered from X-Ray Diffraction confirmed the CeO2 structure, with variable shifts in position strongly related to the dopant percentage. Finally, to ensure that the dopant ions got inside the structure, Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) measurements were conducted after purification of the product. As for the photocatalysis studies, methylene blue (MB) was chosen as a model dye pollutant and a series of samples of different chemical composition were tested. The results exhibited that for the doped samples the catalytic performance was enhanced in comparison to pure CeO2. This was further enhanced when Fe3+ ions were present as a Fenton-like reaction is induced. The best decolouration came from the Ce0.8Er0.1Fe0.1O2 sample, reaching a degradation of 92% of MB in less than 120 minutes due to a synergistic effect between Er3+ and Fe3+ ions, thus proving their efficacy as potential dye degradation candidates. These results also suggest a strong dependence of the catalytic properties of the NPs in the doping agent and percentage, which should be further optimized.
Optimisation of the carbonation process for obtaining a high-purity basic magnesium carbonate. Laboratory scale study
(2026-06) Aldírez Carrasco, Sandra; Formosa Mitjans, Joan; Luque Jiménez, Jorge
This project studies the carbonation process for obtaining high-purity hydromagnesite (HM) [Mg₅(CO₃)₄(OH)₂·4H₂O] from two industrial Mg-based secondary sources: i) low-grade magnesium oxide (LG-MgO) and ii) low-grade magnesium hydroxide (LG-MH). Both are industrial by-products derived from the calcination of natural magnesite by the company Magnesitas Navarras S.A. (MAGNA). The experimental work, carried out at laboratory scale (TRL 3), evaluates the influence of temperature and Mg-based secondary source on the carbonation yield and identifies the optimal operating conditions that maximise it. In addition to the technical study, the project develops a business plan to assess the viability of reactivating the industrial pilot plant previously operated by MAGNA. The analysis covers the value proposition, the market and competitive environment, the production system, the capital and operating expenditures, and the expected economic and environmental results, with the aim of transforming a low-value industrial residue into a high-value-added product with relevant industrial and environmental applications
New strategies for the isolation and characterization of extracellular vesicles in human plasma
(2026-06) Ainaga Pérez, Enric; Peró Gascón, Roger
Extracellular vesicles (EVs), especially exosomes, have attracted considerable attention in recent years as promising biomarkers for biomedical and clinical applications. These nanosized vesicles take part in intercellular communication and carry a wide variety of biomolecules, including proteins, lipids and nucleic acids, which reflect the physiological or pathological state of the cells from which they originate. Because of these characteristics, exosomes are increasingly explored for disease diagnosis, prognosis and therapeutic monitoring, especially in cancer, neurodegenerative disorders and inflammatory diseases. However, the isolation and characterization of EV from human biological fluids remain major analytical challenges. Biological matrices such as plasma hold high concentrations of proteins, lipoproteins and other nanoscale particles that can interfere with EV purification and analysis. In addition, the intrinsic heterogeneity of EV in size, composition and origin complicates the development of standardized and reproducible methodologies. Consequently, the selection of a proper isolation strategy is a critical factor that directly influences the quality, purity and analytical performance of the obtained samples. In the present study, different precipitation- and chromatography-based isolation methods were evaluated and compared to decide their suitability for EV extraction from plasma samples. The isolated fractions were characterized by Dynamic Light Scattering (DLS) and capillary electrophoresis with UV/Vis diode array detection (CE-UV/Vis-DAD). These analytical techniques were employed to assess the size distribution, colloidal behaviour and electrophoretic profiles of the obtained vesicles, as well as to evaluate the capability of the methodologies to isolate exosome-enriched fractions. The results obtained proved that the choice of isolation method has a direct impact on the physicochemical properties of the extracted vesicles, including particle size distribution, signal intensity and electrophoretic behaviour. Differences seen between the analysed samples suggest that each isolation approach may preferentially enrich distinct vesicle populations or co-isolate different plasma components. Furthermore, the study highlights the relevance of complementary analytical techniques for a more reliable characterization of EV and for the detection of possible contaminants or aggregation phenomena associated with the isolation process. Overall, this work emphasizes the importance of carefully selecting the isolation strategy according to the intended analytical or clinical application. The findings contribute to ongoing efforts to optimize and standardize EV characterization methodologies, supporting the development of more robust protocols for exosome-based biomarkers research
Novel nitrone 1,3-dipolar cycloadditions
(2026-06) Winter Silva, Sofía Diana; Romea, Pedro
1,3-Dipolar cycloadditions are a group of pericyclic reactions between a dipolarophile and a dipole that efficiently form five-membered heterocycles, important structures in pharmaceuticals and other biologically relevant compounds. The aim of this work was to optimise the cycloadditions between aliphatic nitrones and chiral thioimides, catalysed by an achiral nickel(II) complex for the synthesis of isoxazolidines. Previous studies, including research carried out within the group, reported that catalysed reactions involving aliphatic nitrones afford poor diastereoselectivities. The main strategy involved modifying the steric hindrance of both the nitrone and thioimides. Since an achiral catalyst was employed, the thioimides used were chiral, required to induce stereoselectivity. These thioimides were derived from commercially available L-β-amino alcohols and L-α-amino acids. A series of cycloadditions were carried out and the yield, conversion and diastereoselectivity were evaluated and quantified by 1H NMR. The results showed that the steric demand of the C4-substituents of the thioimide greatly affected the stereochemical outcome of the reaction, leading to less control over the diastereoselectivity. Overall, the reactions resulted in a mixture of four diastereoisomers, both exo and endo, with one or two diastereoisomers predominating. The relative configuration of the major diastereoisomer is still to be determined. The best results were obtained from the thioimide synthesised from L-phenylglycinol as starting material and the N-benzyl-C-ethyl nitrone. The reaction afforded high yield, almost complete conversion, and a diastereomeric ratio of 79:18:3:0.2.
Bimetallic PtX Nanoalloys as HER Catalysts
(2026-06) Romeo Barceló, Albert; Bruix Fusté, Albert; Telari, Emanuele
The hydrogen evolution reaction (HER) is one of the most promising pathways towards clean hydrogen production, with pure platinum nanoparticles standing as the benchmark catalyst. However, the high cost of platinum drives the search for alloyed alternatives capable of retaining comparable catalytic performance at reduced expense. In this work, PtCu, PtAg, PtAu and PtNi nanoalloys of 201 atoms are investigated across three stoichiometries (Pt:X = 3:1, 1:1, 1:3), with the dual aim of determining their equilibrium chemical ordering and evaluating their hydrogen adsorption energetics toward HER. Structural optimization is carried out via Monte Carlo global optimization using two surrogate energy models of different complexity: the topological (TOP) method and the MACE-MP-0b (Agnesi) machine learning interatomic potential. MACE consistently yields lower-energy and structurally richer chemical orderings than TOP and is adopted as the reference framework. The resulting structures reveal two distinct segregation regimes: Pt segregates to the surface in PtNi, PtCu and PtAg, while Au dominates corner and edge positions in PtAu, a result driven by the relativistic destabilization of Au heterometallic bonds, which causes Au to minimize contacts with Pt and preferentially occupy low-coordination surface positions. Hydrogen adsorption energies are subsequently computed across all surface sites using MACE-MP-0b, totalling 3,876 calculations across the twelve systems. Pt151Cu50 emerges as the most promising candidate, combining 147 sites near the thermodynamic optimum (ΔEH ≈ −0.24 eV) through a mechanistically sound ligand and strain activation of surface Pt by subsurface Cu, at a fraction of the cost of pure platinum. Pt151Ni50 presents the most clearly defined activation mechanism: a pure Pt surface modulated exclusively by subsurface Ni via the ligand and strain effects established in Section 6.1, reproducing the Pt-skin/Ni-subsurface architecture known experimentally for exceptional catalytic activity. PtAu heterometallic sites represent an unexpected durability-activity compromise. PtAg is not recommended as a HER candidate in any stoichiometry studied. A broader methodological finding is that the number of sites within a thermodynamic descriptor window is not a sufficient criterion for catalyst ranking on its own; the electronic mechanism through which those sites achieve their adsorption energy must also be considered, as it determines their true catalytic relevance
Development of High-Throughput Screening Methods for Honey Classification based on UV-Vis and FIA-UV Spectroscopic Fingerprints
(2026-06) Luján Teixidó, Gerard; Núñez Burcio, Oscar
This project focuses on the development, validation, and comprehensive comparison of two rapid, reliable, and high-throughput non-targeted screening methodologies based on UV-Vis and FIA-UV spectroscopic fingerprints combined with chemometrics for honey classification and authentication. To address the issue of food fraud, these optical strategies are proposed as efficient screening systems to perform a preliminary evaluation of honey samples according to both their botanical origin (Spanish honeys from different regions) and geographical origin (international samples from different countries). This approach acts as a first-line filter, avoiding the immediate use of classic confirmatory techniques that are more expensive, time-consuming, and frequently less environmentally friendly. Chemometric analysis consisting in Principal Component Analysis (PCA) and Partial Least Squares-Discriminant Analysis (PLS-DA) provide acceptable sensitivity, specificity and low classification error rates, confirming that non-targeted spectral fingerprints successfully capture key chemical markers, such as polyphenolic and floral absorption descriptors, required for robust differentiation. Regarding method suitability, the automated FIA-UV method proved to be more efficient for the classification of botanical varieties, demonstrating a great capacity to handle high sample volumes due to its high-throughput capability of analysing 30 samples per hour. Conversely, conventional UV-Vis spectroscopy proved to be highly effective for discriminating geographical origins, demonstrating a remarkable capacity to handle the wider chemical variability of international samples through a simpler, budget-friendly setup with lower operational complexity. Both methodologies demonstrate that rapid analytical speed does not imply a sacrifice in classification accuracy. Their highly favourable environmental and operational performances are confirmed by sustainability and operational practicality metrics. Both systems achieved an identical AGREE score of 0.71 by avoiding the use of hazardous organic solvents, while the practical BAGI index yielded scores of 70.0 and 77.5 out of 100 for UV-Vis and FIA-UV, respectively. Therefore, this research provides the beekeeper sector with two valid, eco-friendly, and practical screening alternatives that successfully strengthen honey fraud prevention while ensuring low operational costs and a minimal ecological footprint.
Analysis of neutral per- and polyfluoroalkyl substances (PFAS) in menstrual products
(2026-06) Inglés Giménez, Laia; Giménez López, Estela; Cioni, Lara
Menstruation is an endocrine reproductive process present in all women, characterized by a monthly bleeding of around five days, from menarche to menopause. Throughout the fertile years, it involves the use of approximately 11,000 single-use menstrual products. Vulvar tissues exhibit a high absorption capacity, facilitating the transfer of chemicals contained in these products into the bloodstream. This constant exposure between the vulvar area and such products highlights the necessity to study their composition to assess the potential health risks they may present. Recent studies have demonstrated a significant presence of per- and polyfluoroalkyl substances (PFAS) in menstrual products. PFAS are compounds constituted by fully or partially fluorinated carbon chains attached to a functional group. Both the nature of the functional group and the length of the chain determine properties that influence their adsorption, distribution, metabolism, and excretion. PFAS can act as endocrine disruptors or immunotoxins capable of bioaccumulating in the human body, potentially leading to severe health problems after prolonged exposure, such as fertility disorders or certain types of cancer. Until now, most research has focused on the analysis of ionic PFAS, as neutral PFAS present high analytical complexity due to their volatility. For this reason, the objective of the present study was to develop and analytical method to analyse the presence of specific neutral PFAS, particularly FTOHs, FTACs, and FTMACs, and to compare the concentrations obtained with previous studies and with current regulations. A total of 23 samples of menstrual products were prepared, including reusable products (reusable pads and menstrual underwear) and single-use products (pantyliners and single-use pads). Additionally, a recovery study was carried out to determine the most suitable clean-up method, comparing the use of envicarb dispersive (ED) and envicarb cartridge (EC), due to the complexity of matrix effects present in the samples. Sample preparation consisted of an initial extraction of components using two solvent mixtures (hexane/isopropanol and acetonitrile/methanol), followed by clean-up with ED, established as the most efficient method. Finally, the samples were analysed using GC coupled to Orbitrap-HRMS. The method was validated in terms of reproducibility, and detection limits were established for all analytes under study. Due to a malfunction of the GC-Orbitrap-HRMS instrument, it was not possible to carry out the determination of PFAS in the menstrual products samples extracted for this TFG. Faced with this limitation, a review of previously reported analysis of volatile PFAS in menstrual products was carried. As of today, only one study in menstrual products from the United States was found. In this study, reusable products showed higher PFAS concentrations than single-use products. In the case of reusable products, menstrual underwear was found to present the highest concentrations. As for single-use products, the greatest presence of PFAS was found in single-use pads. Given that current PFAS regulation in products from the United States is similar to regulation in the EU, similar results are expected for the samples extracted in this TFG.
Combining Artificial Intelligence, Quantum Mechanics and Statistical Mechanics for the Design of CO₂ Reduction Catalysts
(2026-06) Hamdaoui Hamdani, El Hassane; Bruix Fusté, Albert; Luque Jiménez, Jorge
This Bachelor’s Thesis addresses, through an integrated scientific and business perspective, the development and potential commercialisation of a computational screening platform for heterogeneous catalysts aimed at CO₂ conversion and utilisation. From a scientific standpoint, the work develops a computational framework that combines three complementary methodologies: Density Functional Theory (DFT) as the reference ab initio approach, Grand Canonical Monte Carlo (GCMC) for exploring the compositional and configurational space of catalytic surfaces under reaction conditions, and Message Passing Atomic Cluster Expansion (MACE) potentials as an efficient surrogate for energy and force evaluations. This framework is applied to the thermodynamic characterisation of oxidised Cu(100) and Cu(111) surfaces, leading to the construction of surface phase diagrams that identify the most stable atomic configurations as a function of the oxygen chemical potential. From a business perspective, the thesis proposes the preliminary design of a university spin-off specialised in computational catalyst screening services for industries linked to catalysis, sustainable fuels, and the energy transition. The proposed value proposition consists of providing advanced simulation-based screening tools to research institutions, chemical companies, refineries, synthetic-fuel producers, and organisations involved in Carbon Capture, Utilisation and Storage (CCUS). Within this context, the Cu/Oₓ system investigated in the scientific part of the thesis serves as both a case study and a technological proof of concept. The economic analysis, based on realistic estimates of experimental characterisation costs, high-performance computing (HPC) resources, and cloud-computing services, indicates that the computational approach can reduce the cost per evaluated structure from approximately €2.300 using conventional experimental methodologies to around €28.31 through computational screening. This corresponds to a cost reduction of nearly 98.8%, while also shortening evaluation times from weeks to only a few hours per structure. Five-year financial projections suggest profitability from the third year of operation, an estimated Internal Rate of Return (IRR) between 22% and 28%, and an investment profile consistent with the growth expectations of a technology-based university spin-off. Overall, the results demonstrate both the scientific viability and the economic potential of integrating artificial intelligence, atomistic simulations, and high-performance computing into catalyst discovery workflows, highlighting their role in accelerating innovation for carbon-utilisation technologies and the broader energy transition.
Design and study of spin-crossover materials for solid-state cooling
(2026-06) Garcia Sánchez, Paola; Díaz Torres, Raúl; Stern Taulats, Enric
The refrigeration and air conditioning industry accounts for roughly 20% of global electricity demand. The contemporary refrigeration system is a vapor compression system. This technology uses hydrofluorocarbon (HFC) refrigerants, which possess global warming potentials up to 14,800 times greater than carbon dioxide. Consequently, solid-state cooling technologies emerge as an interesting, environmentally friendly alternative. These systems take advantage of the inherent caloric effect in solid materials, which undergo reversible entropy changes when an external stimulus is applied. This approach offers significant ecological and operational advantages: it avoids harmful refrigerants and improves overall system efficiency by eliminating the need for mechanical compressors. This work aims to study the caloric effect of spin-crossover compounds, focusing on the understudied elastocaloric effect. Although the barocaloric effect has been proven in spin-crossover compounds, demonstrating their elastocaloric effect is crucial for practical cooling applications. Unlike barocaloric systems that rely on hydrostatic pressure, elastocaloric systems operate with uniaxial stress, which simplifies system implementation for cooling purposes. A specific reported spin-crossover system was chosen to evaluate its potential elastocaloric effect. The compounds were characterized, and a composite synthesis method was established for elastocaloric effect evaluation. Subsequent characterization of the composites confirmed that the spin transition still took place within the polymeric matrix. Several mechanical analyses were made to determine the elastocaloric effect of the composites. Preliminary results were obtained suggesting a possible method for future studies to determine this effect. Based on rational molecular design, new spin-crossover complexes were synthesized to enhance their possible caloric properties. Complete characterization of these systems remains a subject for future studies
Valorisation of viticultural residues into CO2-activated biochar for micropollutant removal from water
(2026-06) Bombardó Heras, Marc; Llopart Roca, Pere; Bayarri Ferrer, Bernardí
The continuous release of trace organic micropollutants (MPs) into aquatic environments represents a major challenge for wastewater treatment, since conventional wastewater treatment plants (WWTPs) are not specifically designed to completely remove persistent contaminants. In response to Directive (EU) 2024/3019, which establishes advanced quaternary treatment requirements for MP removal from urban wastewater, this work evaluates adsorption using biomass-derived activated biochar (AB) as a sustainable and circular alternative to commercial activated carbon. Specifically, three viticultural residues, grape stalks (GS), vine pruning residues (VPR) and grape pomace (GP), were valorised as precursors for CO2-activated biochar aimed at removing two representative indicator MPs from the Directive: venlafaxine (VEN), a Category 1 pharmaceutical compound, and 4-methylbenzotriazole (4BEN), a Category 2 corrosion inhibitor. The ABs were synthesized through sequential N2 pyrolysis and CO2 physical activation at 800 ºC using different activation times. The optimal materials were subsequently subjected to acid washing (AW) to remove pore-blocking inorganic ashes and increase pore accessibility. Feedstocks and ABs were characterized by TGA, elemental analysis, ash content, particle-size analysis, BET, SEM-EDS, FTIR, Raman spectroscopy and XPS. Their adsorption performance was evaluated through preliminary screening, equilibrium isotherms and kinetic experiments, and the experimental data were analysed by non-linear Langmuir, Freundlich, pseudo-first order (PFO), pseudo-second order (PSO) and Elovich models. The results demonstrated a strong precursor-dependent activation behaviour. GS developed adsorption-accessible porosity rapidly, reaching its optimal performance at 80 min, whereas VPR required 120 min to achieve the best balance between pore development and structural preservation. GP showed a slower and less efficient activation response, mainly attributed to restricted CO2 diffusion, compact bed formation and poorer development of an accessible microporous network. Pyrolysis alone was insufficient for efficient MP removal, while excessive CO2 activation caused overactivation, pore widening, carbon burn-off and loss of adsorption capacity. AW proved essential, reducing ash content to 0.84% for GS-80′-AW, 0.67% for VPR-120′-AW and 1.71% for GP-120′-AW, while increasing the specific surface area up to 1303.9 m2 g-1 for GS-80′-AW and 1286.6 m2 g-1 for VPR-120′-AW, both above the commercial F 400 reference. The optimized GS- and VPR-derived ABs outperformed Chemviron FILTRASORB 400 in equilibrium adsorption. According to the Langmuir model, GS-80′-AW reached maximum capacities of 254.78 mg g-1 for VEN and 338.55 mg g-1 for 4BEN, while VPR-120′-AW reached 293.78 mg g-1 for VEN and 270.24 mg g-1 for 4BEN. Adsorption was governed by a mixed mechanism involving micropore filling, π-π electron donor-acceptor interactions, hydrophobic effects and, for cationic VEN at pH 7, electrostatic attraction. The Freundlich model described 4BEN adsorption well on the AW ABs, indicating heterogeneous active sites, whereas VEN showed a more precursor-dependent behaviour. Kinetically, 4BEN was adsorbed faster due to its smaller, planar and neutral structure, while VEN uptake was more limited by molecular size, steric hindrance and intraparticle diffusion. Overall, this work validates GS and VPR as promising local precursors for producing high-performance, zero-kilometre ABs for circular quaternary wastewater treatment.
Effect of Blanching Pretreatment on Polyphenol Extraction Efficiency from Pea Pod Industrial Waste
(2026-06) Ayats i Ferrer, Clàudia; Saurina, Javier; Khan, Imran
The increasing interest in the valorisation of agro-industrial by-products has led to the development of strategies for the recovery of bioactive compounds while contributing to sustainability and the circular economy. In this study, pea pod waste has been evaluated as a potential source of bioactive compounds with antioxidant properties. The effect of blanching pretreatment on the recovery of phenolic compounds has been evaluated together with the influence of temperature and blanching time and extraction solvent composition using a full factorial design. The obtained extracts have been characterized by Total Phenolic content (TPC), Ferric Reducing Antioxidant Power (FRAP) and HPLC total peak area analysis in order to assess phenolic recovery and antioxidant capacity. Since the optimal processing conditions may vary depending on the perspective considered, the process has been assessed from analytical, energetic and economic points of view. While the analytical optimum represents the conditions that maximise the recovery of bioactive compounds, the economic optimum also takes into account energy consumption and processing costs. Considering all these aspects, the economic criterion has provided the most suitable overall solution. The optimal conditions identified in this study have been found to be 86 ºC, 1 min and 20% ethanol-water (v/v). Furthermore, HPLC-MS/MS analysis has been carried out to characterise the chemical composition of the extracts. The results have allowed the tentative identification of several phenolic compounds: cinnamic acid derivatives, benzoic acid derivatives and flavonoids; it has been detected a non flavonoid compound compatible with citric acid too. Summarizing, the results demonstrate that blanching is an effective pretreatment for improving the recovery of bioactive compounds from pea pod waste and support the potential valorisation of this agro-industrial by-product as a suitable source of natural antioxidant compounds.
Development of an RP-HPLC Peptide Mapping Method for the Identification of a GLP-1 Receptor Agonist in Tablets
(2026-06) Ruiz Borao, Adrià; Sahuquillo Estrugo, Àngels; Pérez Martin, Lara
In the pharmaceutical industry, the development of analytical methods capable of ensuring the identity, purity, potency and stability of a pharmaceutical product is a critical step in pharmaceutical product development. These methods ensure the quality and safety of the product prior to its commercialization. This Final Degree Project presents the development, and analytical evaluation of an identification method for an active pharmaceutical ingredient (API) in a pharmaceutical product. The developed procedure is a qualitative peptide mapping method using reversed-phase high-performance liquid chromatography coupled with diode array detection (RP-HPLC-DAD). The primary objective is to confirm the unambiguous identity of a biologically derived drug by comparison with a laboratory standard of the API. The studied product is a glucagon-like peptide-1 (GLP-1) receptor agonist formulated as an oral dosage form (tablets). The main challenge of this development lies in the extreme complexity of the drug matrix, which is heavily dominated by a gastric absorption enhancer (referred to as Excipient 1). This excipient protects the active pharmaceutical ingredient (API) from enzymatic degradation in vivo but severely interferes with the analytical stages. The initial analytical strategy involved the selection of a suitable chromatographic system and selective enzymatic digestion of the peptide using Glu-C protease, designed to generate a characteristic profile of six peptide fragments. However, excipient 1 caused interferences with this process. Due to the presence of this compound, one of the peptide fragments was not detected. According to regulatory agencies like the European Medicines Agency (EMA), the recovery of all peptide fragments is a key aspect of this method, thus making this procedure unsuitable for routine quality control. Various physical sample pre-treatment methodologies were systematically evaluated to isolate the API from the matrix prior to the digestion stage, but none provided satisfactory analyte recovery. Given the impossibility of achieving a robust physical separation, the research was reoriented towards the optimization of the digestion buffer strength and pH and the chemical stabilization of the excipient in solution via the controlled addition of a non-polar solvent. However, the addition of a non-polar solvent caused peak splitting and band broadening of the more polar and hydrophilic fragments. The final resolution of the method was not achieved, but it will probably imply the chemical stabilization of excipient 1 through the addition of an organic solvent. Although substantial improvements were achieved throughout the method development process and the major limitation of the initial procedure (the non-detection of a peptide fragment) was successfully addressed, the final method could not be further optimized or subjected to a comprehensive evaluation of its repeatability and validation parameters within the timeframe of this project.

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Treballs Finals de Grau (TFG) - Química

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Amb motiu del tancament d'estiu, la validació de documents es reprendrà a partir del 28 d'agost de 2026. Disculpeu les molèsties.

Con motivo del cierre de verano, la validación de documentos se reanudará a partir del 28 de agosto de 2026. Disculpad las molestias

Due to the summer closure, document validation will resume starting August 28, 2026. We apologize for any inconvenience.

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