Artículos (Química Física)

URI permanente para esta colecciónhttps://hdl.handle.net/11441/10914

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Electrochemically generated metal-doped 2D-cobalt(M)MOFs@C derivatives for boosting the electrocatalytic oxidation of glycerol to formate
(Elsevier, 2026-08-28) Hernández Salvador, Sergio; Río Rodríguez, José Luis del; Montiel, Miguel A.; Molina, M. Asunción; Gutiérrez Tarriño, Silvia; Calvente Pacheco, Juan José; Beale, Andrew M.; Oña Burgos, Pascual; Solla Gullón, José; Olloqui Sariego, José Luis; Química Física; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; European Union (UE); Ministerio de Ciencia e Innovación (MICIN). España; Generalitat Valenciana
Glycerol is an underutilized waste product that is abundantly available from the biodiesel industry. Electrocatalytic oxidation of glycerol (GOR) to formate offers an environmentally friendly and cost-effective approach to valorizing glycerol. In this study, we have developed new types of metal-doped cobalt metal-organic frameworks, which are grown directly on a carbon matrix via a one-pot synthesis as electrocatalyst precursors. In-depth structural analysis has revealed that, in the Ni-doped cobalt MOF, Ni substitutes a fraction of Co sites isomorphically, forming isolated Ni(II) centers, while Cu is present as a mixture of Cu(II) and metallic Cu, with the majority in the oxidized form as highly dispersed species and a small fraction forming nanoparticles. These materials were then subjected to a controlled potential-induced surface reconstruction to produce mixed-metal oxide/oxyhydroxide-like environments interconnected through M-O-M motifs, the extent of the reconstruction depending strongly on the dopant metal. The metal-doped derivatives were tested as electrocatalysts for the alkaline electrooxidation of glycerol using in-house designed electrochemical reactors with different cell configurations and operating modes. We demonstrated that metal-doped derivative phases exhibit improved electrocatalytic activity for GOR compared to the monometallic counterpart. These catalysts yield significant glycerol conversion rates under single-pass operation, with improved Faradaic efficiencies towards formate (up to 70%) and low energy consumption (< 320 kWh kmol−1), while suppressing the complete oxidation of glycerol to carbonate or CO2. This work provides new insight into the rational design of metal-doped MOF derivatives as highly active and selective electrocatalysts for the practical glycerol valorization.
Imidazole-based Ru(III) complexes: synthesis, characterisation and anticancer activity.
(Royal Society of Chemistry, 2026-07-15) Estruch Blasco, Manel; Calderón Montaño, José Manuel; Álvarez, Eleuterio; Sánchez Coronilla, Antonio; López Lázaro, Miguel; Pernía Leal, Manuel; Química Orgánica y Farmacéutica; Farmacología; Química Física; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Agencia Estatal de Investigación. España; Junta de Andalucía
In this work, we prepared a series of substituted imidazole-derived Ru(III) complexes, ImRu1–ImRu5, analogous to the clinically evaluated NAMI-A. These Ru(III) complexes, with different functional groups on the imidazole ring, were characterised by 1H NMR and UV-Vis spectroscopy, elemental analysis, low- and high-resolution mass spectrometry, and single crystal X-ray diffraction. The cytotoxicity of the Ru(III) complexes was evaluated in vitro against different cancer and non-cancer cell lines, exhibiting low cytotoxicity activity and antimigratory characteristics comparable to those of the NAMI-A complex, except for the Ru (III) complex bearing an alkyne substituent on the imidazole ring (ImRu3). ImRu3 exhibited selective cytotoxicity against A549, MeWo and T24 cells, while retaining antimigratory activity against T24 cells, indicating that modifications at the imidazole ligand can modulate biological behaviour. Computational and fluorescence studies suggest that functional variations of the imidazole ligand enhance albumin-binding affinity, potentially facilitating transport and contributing to the observed anticancer activity.
High-Entropy Skutterudites as Thermoelectrics: Potential Synthesizability, Enhanced Stability, and Band Convergence via the Cocktail Effect
(American Physical Society, 2026-02-19) Plata Ramos, José Javier; Morales Altarejos, Antonio; Rodríguez Remesal, Elena; Posligua Hernández, Víctor Hugo; Márquez Cruz, Antonio Marcial; Química Física; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Red Española de Supercomputación
High-entropy materials offer a promising avenue for thermoelectric materials discovery, design, and optimization. However, the large chemical spaces that need to be explored hamper their development. In this work, a large family of high-entropy skutterudites is explored as promising thermoelectric materials. Their potential synthesizability is screened and rationalized using the disordered enthalpy-entropy descriptor through high-throughput density functional theory calculations. In the case of high-entropy skutterudites, the thermodynamic density of states and the entropy gain parameter appear to be key factors for their stabilization. Electronic band structure analyses not only show a reduction in the band gap, which enhances carrier concentration and electrical conductivity, but also a band convergence phenomenon for some specific compositions, which is related to the “cocktail effect.” Analyzing atom-projected band structures shows how band convergence is due to the simultaneous presence of Fe, Ni, and Co in the compound. The presence of Rh or Ir, while not contributing to this band-convergence effect, can be directly linked to an increase in the system’s entropy, which enhances the thermodynamic stability of these materials. Transport properties are computed for the most promising compositions, and their dynamical, mechanical, and thermal stability are addressed. Our results demonstrate that these types of compounds open new avenues, not only to enhance thermoelectric efficiency but also to reduce costs by utilizing more abundant elements and also improving their durability.
Principles of Biocompatible Nanotube Design for High-Performance Biomaterials
(Wiley, 2026-08-06) Zhong, Yue; Lebrón Romero, José Antonio; López López, Manuel; Ostos Marcos, Francisco José; López-Cornejo, María del Pilar; Moyá Morán, María Luisa; Química Física; Junta de Andalucía; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Universidad de Sevilla
Nanotubes are one-dimensional tubular structures characterized by nanoscale radial dimensions and micrometer-scale axial lengths. Their hollow inner cavity confers a high specific surface area and distinctive physicochemical properties, enabling remarkable potential in drug delivery, disease diagnostics, and tissue engineering. Extensive research into their biocompatibility and degradability establishes a solid foundation for further development and rational design. A synthesis of current data across relevant systems, including carbon nanotubes (CNTs), boron nitride nanotubes (BNNTs), titanium dioxide nanotubes (TiNTs), halloysite nanotubes (HNTs), anodic aluminium oxide nanotubes (AAOs), lipid nanotubes (LNTs), and polymeric nanotubes (PNTs), reveals how structural features and physicochemical properties govern biological responses and functional performance. This integration supports a unified “structure–property–bioresponse–function” framework, offering a conceptual roadmap and general design principles to guide the next generation of nanotube-based biomaterials.
Development of Nanosystems Delivering with Eco-Friendly Antibacterial Agents Composed of Zingiber officinale/Alpinia galanga and Gold, as Sustainable Antibiotics
(MDPI, 2026-07-21) Giráldez Pérez, Rosa María; Grueso Molina, Elia María; Carbonero, Alfonso; Carpintero López, Antonio; Prado Gotor, Rafael; Química Física; Junta de Andalucía; Universidad de Sevilla
Background/Objectives: Green antibacterial synthesis is a natural alternative to chemical methods, aligning with the Sustainable Development Goals by being beneficial to the environment and contributing to new therapies to combat antibiotic resistance. In this research, a simple method was developed for producing nanosystems with natural extracts of Ginger (Zingiber officinale) or Galangal (Alpinia galanga) with gold. Then, their antibacterial efficacy was evaluated and compared against strains of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Methods: After optimizing the systems, the core size of the nanosystems was determined using transmission electron microscopy (TEM), and the presence of gold was confirmed with EDS. Stability control was measured using spectrometry, and the systems were characterized by measuring zeta potential and dynamic light scattering (DLS). Finally, to verify the antibacterial effect, minimum inhibitory concentration (MIC) assays were performed. Results: The analysis of the MIC experiments confirmed that the Galangal nanosystem (Au@Galangal showed better results against both bacteria. In the case of the Ginger nanosystem (Au@Ginger), the most evident results were against E. coli. Internalization studies demonstrated the antibacterial efficacy of all the nanosystems analyzed. Conclusions: The results suggest that nanosystems obtained entirely by green methods have great potential as alternative antimicrobial agents, especially against resistant strains, representing a major advance in the development of sustainable bactericidal nanosystems.
New Ru(III) NAMI/NAMI‑A Analogue Complexes with Selective Anticancer Activity
(American Chemical Society, 2026-07-23) Estruch Blasco, Manel; Calderón Montaño, José Manuel; Álvarez, Eleuterio; Sánchez Coronilla, Antonio; López Lázaro, Miguel; Pernía Leal, Manuel; Química Orgánica y Farmacéutica; Farmacología; Química Física; Instituto de Investigaciones Químicas (IIQ); Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Agencia Estatal de Investigación. España; Junta de Andalucía
NAMI-A (ImH)[trans-RuCl4(dmso-S)(Im)], where dmso-S = sulfur-bonded dimethyl sulfoxide and Im = imidazole emerged as a promising alternative to approved Pt(II) anticancer drugs, offering high antimetastatic activity and low toxicity. However, its development was discontinued due to insufficient activity against primary tumors. In this work, we synthesized 12 new pyridine NAMI derivatives and evaluated their anticancer activity against three cancer cell lines: lung adenocarcinoma A549, melanoma MeWo and bladder cancer T24, and compared with the nonmalignant keratinocyte HaCaT cells. Among them, two complexes exhibited potent cytotoxicity and selectivity while retaining the characteristic antimetastatic activity of the NAMI scaffold. The Ru(III) complex (CHO-PyH)[trans-Ru(CHO-Py)Cl4 (dmso-S)], where CHO-Py = pyridine-3-aldehyde, displayed an IC50 of 34 μM and a selectivity index of 7.60 against A549 cells. Additionally, (NCS-PyH)[trans-RuCl4(dmso-S)(NCS-Py)], where NCS-Py = 3-(isothiocyanatomethyl)pyridine, showed an IC50 of 240 nM and a selectivity index of 5.2 against T24 cells.
Insights into the stability and thermal properties of WSe2-based nanofluids for concentrating solar power prepared by liquid phase exfoliation
(Elsevier, 2020-09-24) Martínez Merino, Paloma; Sánchez Coronilla, Antonio; Alcántara, Rodrigo; Martín Fernández, Elisa Isabel; Navas, Javier; Química Física; Ingeniería Química; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; European Union (UE); Junta de Andalucía
Nanofluids are considered the new generation of heat transfer fluids thanks to their improved thermophysical properties compared with conventional fluids. However, little research has been performed into the thermal properties, stability and preparation of nanofluids based on two-dimensional nanostructures. In this paper, we discuss the preparation of nanofluids based on 2D-WSe2 nanostructures prepared by liquid phase exfoliation applying two different sources of ultrasound. The base fluid for these nanofluids is a eutectic mixture of biphenyl and diphenyl oxide used as a heat transfer fluid in the parabolic trough collectors of concentrating solar power plants. The 2D-WSe2-based nanofluids were characterized for their stability and thermal properties. Treatment with ultrasonic tip resulted in remarkable improvements in the exfoliation of the nanomaterial and stable nanofluids. At a molecular level, periodic-DFT calculations were performed to understand the stability of the 2D-WSe2-based nanofluids from the perspective of the arrangement of the surfactant molecules around the WSe2 nanosheets. The results suggest that the most favoured interaction with the WSe2 sheets occurs through the hydroxyl terminal group of Triton-X. The hydrogen bond interaction between the H atom of the -OH group of Triton-X and three Se atoms on the surface of the sheet plays a stabilizing role in the system. Thus, the arrangement of the surfactant must facilitate the exfoliation of the WSe2 sheets. Furthermore, WSe2 nanosheets were found to improve the thermal conductivity by up to 39% and the specific heat by up to 9.3%, resulting in an increase in the heat transfer of up to 26%. The results of this study have revealed the great potential of 2D-WSe2 based nanofluids as heat transfer fluids in CSP plants.
Deep learning framework for accurate prediction and high-throughput search of the thermoelectric figure of merit in skutterudites
(Royal Society of Chemistry, 2026-04-20) Posligua Hernández, Víctor Hugo; Landivar, Karina; Rodríguez Remesal, Elena; Rogl, Gerda; Rogl, Peter F.; Fernández Sanz, Javier; Prado-Gonjal, Jesús; Márquez Cruz, Antonio Marcial; Plata Ramos, José Javier; Química Física; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Agencia Estatal de Investigación. España; European Union (UE)
The integration of artificial intelligence and machine learning is rapidly transforming the landscape of materials discovery, facilitating unprecedented acceleration in the exploration of vast chemical spaces and the prediction of material properties. However, the adoption of these advanced techniques has not been uniform across all subfields of materials science; thermoelectrics, for instance, has experienced relatively slower penetration. This lag can be attributed to several inherent challenges, including the physical complexity of thermoelectric phenomena, the scarcity and reliability issues of available data, and limitations concerning the applicability of general models. To address these challenges, in this work, we have developed a machine learning model, based on neural networks, specifically for the accurate prediction of the thermoelectric figure of merit (zT) in skutterudites. This model demonstrates high accuracy, with prediction errors approaching the range of experimental uncertainties reported for zT measurements. Furthermore, it offers the crucial capability of extracting design rules grounded in the underlying physics and chemistry of these materials, providing valuable insights for optimization. Most importantly, our model is applicable for the high-throughput screening of extensive chemical spaces, facilitating the efficient discovery of novel and high-performance thermoelectric materials.
Binding and reactivity under restricted geometry conditions: Applicability of the Pseudophase Model to thermal and photochemical processes
(Elsevier, 2017-11) López-López, Manuel; López-Cornejo, María del Pilar; Lebrón Romero, José Antonio; Ostos Marcos, Francisco José; Moyá Morán, María Luisa; Química Física; Junta de Andalucía; European Union (UE)
Reactivity under restricted geometry conditions can be quantitatively rationalized by using the Pseudophase Model. This model considers two states in equilibrium, free and bound, which are not perturbed by the reaction. That is, the reaction in which the two states participate must be slow in comparison to the exchange process between the free and bound states. This condition is fulfilled in the case of chemical reactions, but it does not hold for fast photochemical reactions. In spite of this, the Pseudo-phase Model was found to be, at least apparently, applicable for excited state reactions. However, a thorough analysis of the kinetic data brings to light important differences between the two types of reactions, particularly in the meaning of the parameters present in the equations of the Pseudophase Model.
P-Sulfocalix[6]arene as Nanocarrier for Controlled Delivery of Doxorubicin
(Wiley, 2017-01-23) Ostos Marcos, Francisco José; Lebrón Romero, José Antonio; Moyá Morán, María Luisa; López-López, Manuel; Sánchez, Antonio; Clavero, Amparo; García-Calderón, Clara B.; Valle Rosado, Iván; López-Cornejo, María del Pilar; Química Física; Genética; Junta de Andalucía; European Union (UE)
Given the high toxicity of the anthracycline antibiotic called doxorubicin (DOX), it is relevant to look for nanocarriers that, decreasing the side effects of the drug, were able to transport it towards a therapeutic target. Accordingly, the encapsulation of DOX by p-sulfocalix[6]arene (calix) has been studied. The interaction of DOX with the macrocycle, as well as with DNA, has been investigated and the equilibrium constant for each binding process estimated. Results showed that the binding constant of DOX to DNA, KDNA, is three orders of magnitude higher than that to calix, Kcalix. A multidisciplinary study has been done to demonstrate the ability of calixarenes to encapsulate DOX molecules, as well as the power of the DOX molecules included into the inner cavity of the macrocycle to bind with the DNA. Citotoxicity measurements were done in different cancer cell lines to probe the decrease in the toxicity of the encapsulated DOX, demonstrating thus the decrease of its side effects in the human organism. The low toxicity of calixarenes has also been demonstrated for different cancer cell lines.
Dinuclear Fe(II) Spin-Crossover Complex Deposited on the Au(111) Surface: Exploration Based on Quantum-Chemistry Calculations
(American Chemical Society (ACS), 2025-03-11) El Lala, Iman Jaber; Sánchez de Armas, María Rocío; Jiménez Calzado, Carmen; Química Física; Ministerio de Ciencia, Innovación y Universidades (MICIU). España
We present the first computational study dealing with the interaction of a dinuclear Fe(II) spin-crossover complex with a metal surface. Density functional theory-based calculations have been employed to determine the electronic structure and geometry of the deposited molecules and the persistence of the spin transition. The studied dinuclear Fe(II) complex presents a two-step transition in the bulk, switching abruptly from the [LSLS] to the [LSHS] state and gradually from the mixed state to the [HSHS] state. Our results confirm the same behavior for a single molecule in the absence of packing interactions. When deposited on gold, the molecule preferentially adopts a vertical orientation, with respect to the surface. The mixed spin state [LSHS] is favored over the pure [LSLS] and [HSHS] states, with a noticeable distortion of the coordination sphere of the Fe HS center close to the metal surface. Although the separation with the [LSLS] state is small, the transition from the [LSHS] to [LSLS] state would be blocked by the negative entropy change. A second conformer, higher in energy, has also been identified, where the axial axes of the Fe coordination octahedra are parallel to the surface. In such a case, the [LSLS] solution is the ground state, and a thermal switching to the mixed [LSHS] state would be possible at a rather low temperature. In all of the conformations explored, the [HSHS] solution is too high in energy, and a complete switching to the [HSHS] state is then discarded for the deposited molecule at room temperature.
A cobalt MOF-derived electrochemical platform for dual detection of glucose and hydrogen peroxide
(Elsevier, 2026-10-01) Portorreal Bottier, Arismendy Antonio; Márquez Escudero, Inmaculada; Gutiérrez Tarriño, Silvia; Río Rodríguez, José Luis del; Calvente Pacheco, Juan José; Oña Burgos, Pascual; Andreu Fondacabe, Rafael Jesús; Olloqui Sariego, José Luis; Química Física; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; European Union (UE)
The development of reliable non‑enzymatic electrochemical sensors based on transition metal oxides has attracted great attention for monitoring and quantification of biomolecules, including glucose and hydrogen peroxide. Metal-organic frameworks (MOFs) serve as tunable sacrificial precursors for generating stable, porous metal oxide or oxyhydroxide phases, particularly for applications in electrocatalysis. In this work, we developed an in situ derivatization strategy consisting of the electrochemically-assisted surface reconstruction of a cobalt MOF to form the derived cobalt oxyhydroxide phase as an efficient electrochemical sensing platform for dual detection of glucose and hydrogen peroxide. The resulting catalytic phase exhibits electrocatalytic activity toward both glucose oxidation—mediated by the Co(III)/Co(IV) redox couple—and the direct electroreduction of hydrogen peroxide. The as-fabricated amperometric dual sensor provides fast response times, wide linear ranges (up to 10 mM), good reproducibility, and high selectivity against common interferents. Sensitivities up to 200 μA mM- 1 cm- 2 and 320 μA mM- 1 cm- 2 for glucose and hydrogen peroxide, respectively, are achieved, with detection limits in the low micromolar range. Structural stability of the derived phase under operational conditions was confirmed by operando Raman spectroscopy during prolonged amperometric experiments. Furthermore, a bipotentiostatic configuration enables the simultaneous quantification of both analytes using two independently biased working electrodes. The dual-in‑line platform maintains linearity across a broad concentration range and preserves a good sensitivity even under mixed‑analyte conditions. These results highlight the potential of electrochemically reconstructed MOF‑derived phases as robust and versatile materials for high‑performance multimodal sensing technologies.
Plant-Based Flavones of Therapeutic Interest Loaded into Polymeric Nanoparticles
(MDPI, 2026-05-29) Espíndola, Cecilia; Martín, Victoria I.; Bernal Pérez, Eva; Lebrón Romero, José Antonio; Moyá Morán, María Luisa; Ruiz de la Haba, Rafael; Sánchez-Porro Álvarez, Cristina; Ventosa Ucero, Antonio; Granados Carrera, Carmen M.; López-Cornejo, María del Pilar; Ostos Marcos, Francisco José; Química Física; Microbiología y Parasitología; Ingeniería Química; Gobierno de España; Junta de Andalucía; Universidad de Sevilla
Background/Objectives: Flavonoids are low-molecular-weight polyphenolic compounds that are universally distributed in plants. They are a chemically varied group of secondary metabolites with a broad range of biological activity. The use of flavonoids is known to decrease the risk of many chronic diseases due to their radical scavenging, antioxidant, anti-inflammatory, anticarcinogenic, and antimutagenic properties. Limitations in the use of flavonoids include their low water solubility and poor stability, and therefore their low bioavailability. The encapsulation of flavonoids in different nanocarriers has helped to overcome this limitation. Taking this into account, in this work, the encapsulation of four flavones with several therapeutic applications—7-hydroxyflavone, 7,8-dihydroxyflavone, baicalein, and luteolin—in poly(lactic-co-glycolic) acid (PLGA)-derived polymeric nanoparticles (NPs) has been investigated. Methods: A physicochemical characterization of the NPs has been carried out using different techniques, including the evaluation of antioxidant and antimicrobial activities. Results: In all cases, the incapsulation efficiency of the four flavones in the prepared NPs was high (>90%), the zeta potential was about −31 mV, and the size was nanometric (~450 nm). The drug release from the nanoparticles was also studied, showing first-order kinetics. Statistical tools were applied to the release rate constants. The antioxidant activity and the in vitro antimicrobial activity of the free and flavone-loaded NPs were investigated, in the case of the latter using Gram-positive and Gram-negative bacteria. Results show that when the flavones are encapsulated, they retain their therapeutic properties. Conclusions: In summary, PLGA-based NPs not only prevent flavone degradation but also significantly boost solubility, ultimately optimizing bioavailability. Our results underscore these NPs as a promising platform for efficient flavone delivery.
Enhanced thermoelectric performance in Fe2V0.8W0.2Al thin films: synergistic effects of chemical ordering and tungsten substitution
(Royal Society of Chemistry, 2026-02-20) Domínguez-Vázquez, José María; Tenaguillo, Miguel Ángel; Lohani, ketan; Caballero-Calero, Olga; Manzano, Cristina; Plata Ramos, José Javier; Márquez Cruz, Antonio Marcial; Cebollada, Alfonso; Conca, Andrés; Martín-González, Marisol; Química Física; Comunidad Autónoma de Madrid; Ministerio de Economia, Industria y Competitividad (MINECO). España; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; European Union (UE)
We systematically investigate the combined effect of chemical ordering and W substitution on the thermoelectric properties of Fe2V0.8W0.2Al thin films. Through controlled sputter deposition on MgO (100) and Al2O3 (11 20) substrates at temperatures ranging from 350 °C to 950 °C, we achieve varying degrees of crystalline and chemical order. Films deposited between 750 °C and 950 °C adopt the highly ordered L21 phase, exhibiting a dramatic enhancement in Seebeck coefficient and substantial reduction in thermal conductivity compared to isostructural Fe2VAl thin films without tungsten substitution. These synergistic improvements, attributed to electronic structure modifications and enhanced phonon scattering mechanisms, yield exceptional thermoelectric performance with maximum power factors of 730 ± 70 mW m−1 K−2 and figure of merit zT = 0.12 ± 0.03 at room temperature, representing a more than four-fold enhancement over undoped Fe2VAl and demonstrating the potential for sustainable energy harvesting applications.
Phonon Scattering by Local Off-Centering in Diamond-Like Cu2−XAgxIn2Se4 Chalcopyrites: High Carrier Mobility and Ultralow Thermal Conductivity
(Wiley, 2026) Caro-Campos, Irene; Posligua Hernández, Víctor Hugo; Prado-Gonjal, Jesús; Dura, Oscar J.; Nemes, Norbert M.; Gainza, Javier; Martínez, José L.; Márquez Cruz, Antonio Marcial; Plata Ramos, José Javier; Serrano-Sanchez, Federico; Química Física; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Agencia Estatal de Investigación. España; European Union (UE)
Diamond-like Cu2−xAgxIn2Se4 (x = 0–0.3) chalcopyrites were synthesized by arc-melting and investigated as sustainable, tellurium-free thermoelectric (TE) materials. Synchrotron X-ray diffraction reveals that partial Ag substitution induces lattice expansion andlocal off-centering distortions within the tetrahedral Cu/Ag-Se network, resulting in pronounced anisotropic atomic displacementparameters. This dynamic lattice disorder, reminiscent of emphanitic behavior, enhances phonon scattering and drives a markedreduction of the lattice thermal conductivity down to 1.25 W m−1 K−1 at 748 K. Despite a moderate carrier concentration( 1018 cm−3), the alloys maintain high carrier mobility up to 400 cm2 V−1 s−1, yielding a power factor of 0.33 mW m−1 K−2 forCu1.9Ag0.1In2Se4. Hybrid-functional density functional theory calculations confirm progressive bandgap widening with unalteredconduction-band curvature, consistent with the transport trends. These findings reveal a direct nanoscale structure–property rela-tionship in Ag-alloyed CuInSe2 chalcopyrites, where local off-centering acts as an intrinsic phonon-scattering mechanism. The workestablishes a sustainable, tellurium-free platform for designing high-mobility TEs through controlled lattice disorder.
Molecular Switches and Real-Time Ion Sensing in Pyridinium Circuits via Single-Molecule STM-Break Junction
(Royal Society of Chemistry, 2025-08-27) Méndez Torres, A. M.; Oñate, Rubén; Pizarro, Ana; Monje, Dany S.; Montenegro-Pohlhammer, Nicolás; Darwish, Nadim; Cortés-Arriagada, Diego; Cárdenas-Jirón, Gloria; Ponce, Ingrid; Química Física
The functional electronic and spectro-electrochemical properties of two structural pyridinium isomers, Py_Down-BF₄ and Py_Up-BF₄, were studied at the single-molecule level by STM-BJ. These isomers differ in the position of the redox-active pyridinium core. The aim was to identify the core's position influence to promote reversible switching between electromers (redox isomers) in solution and at the gold-pyridinium-gold junction circuit. We measured the single-molecule conductance of each pyridinium isomer in various electrolyte environments using tetrabutylammonium salts (TBABF₄, TBAPF₆, TBABr, and TBACl). The choice of electrolytes played a crucial role in the histograms' shapes—junction distribution, width, and peak position—functioning as unique conductance fingerprints for each isomer. During STM-BJ measurements, a dynamic evolution in the conductance histograms was determined, particularly with the electrolytes TBAPF₆ and TBABF₄. This behavior was attributed to the real-time detection of interactions between the positively charged pyridinium core and the electrolyte anions within the gold–pyridinium–gold junction. The dynamic evolution in single-molecule conductance was rationalized by the Gibbs free energies (ΔG) for the anion-cation pairs obtained from density functional theory (DFT) calculations. Furthermore, the theoretical trend predicted by DFT combined with the Keldysh nonequilibrium Green's function (NEGF) formalism (DFT-NEGF) was consistent with the experimental results.
Stability constants and DFT calculations of anionic calixarene complexes with antiretroviral drugs Tenofovir and Emtricitabine
(Springer, 2025-01-08) Kalchenko, Olga I.; Rozhenko, Alexander B.; Cherenok, Sherii O.; Selikhova, Anna I.; Drapailo, Andryi B.; López-Cornejo, María del Pilar; Kalchenko, Vitaly I.; Química Física; Consejería de Economía, Conocimiento, Empresas y Universidad de la Junta de Andalucía
Stability constants of supramolecular host-guest complexes between water-soluble sodium salts of thiacalix[4]arene sulfonic acid (TCS), thiacalix[4]arene methylphosphonic acid (TCPA), calix[4]arene methylene-bisphosphonic acid (CMBPA) (hosts) and the antiretroviral drugs Tenofovir (TFV) and Emtricitabine (FTC) (guests) were determined by HPLC method in 90/10, (v/v) water/acetonitrile solution (KA values 1.2 × 103 − 9.3 × 103 M− 1). DFT calculations show that the conformationally flexible calixarenes adopt the conformation (cone or 1,3-alternate preferably) suitable to form a number of intermolecular hydrogen bonds with the guest molecules. The water-soluble, low cytotoxic, synthetically available anionic calixarenes TCSA, TCPA and CMBPA with practically unlimited possibilities of chemical modification have the prospect of application in formulations of the antiretroviral drugs and the creation of vectors for their delivery systems.
MoS2 nanosheets vs. nanowires: preparation and a theoretical study of highly stable and efficient nanofluids for concentrating solar power
(Royal Society of Chemistry (RSC), 2018) Navas, Javier; Martínez-Merino, Paloma; Sánchez Coronilla, Antonio; Gallardo, Juan Jesús; Alcántara, Rodrigo; Martín Fernández, Elisa Isabel; Piñero, José C.; León, Juan R.; Aguilar, Teresa; Hidalgo Toledo, José; Fernández-Lorenzo, Concha; Química Física; Ingeniería Química; Ministerio de Economía y Competitividad (MINECO). España
The nano-colloidal suspension of nanomaterials in a base fluid, typically named a nanofluid, is a promising system that shows interesting properties, such as those related to heat transfer processes. Obtaining nanofluids with high stability is a priority challenge for this kind of system. So, a rationalization of the preparation of nanofluids is clearly needed. Thus, this study presents a methodology based on liquid phase exfoliation that makes it possible to prepare stable nanofluids and control the morphology of the nanostructures, which is defined by the surfactant used. Two stable nanofluids were prepared based on MoS2 nanosheets and MoS2 nanowires and a typical heat transfer fluid (HTF) used in high temperature applications. Periodic-Density Functional Theory (periodic-DFT) calculations were performed to rationalize why different nanostructures were obtained according to the surfactant used. Finally, enhancements in thermal properties were found, being up to 57% for thermal conductivity and up to 7.5% for isobaric specific heat. Therefore, these nanofluids are a promising alternative to the typical HTF used, which is a eutectic mixture of biphenyl and diphenyl oxide. Also, to our knowledge, controlling the nanostructures obtained and the rationalization of the methodology for the preparation of stable nanofluids is reported for the first time. This leads to highly stable nanofluids with improved thermal properties, promising for application in concentrating solar power.
Towards a Realistic Theoretical Electronic Spectra of Metal Aqua Ions in Solution: The Case of Ce(H2O)3+ n Using Statistical Methods and Quantum Chemistry Calculations
(American Institute of Physics, 2024-10) Raposo Hernández, Gema; Rodríguez Pappalardo, Rafael; Real, Florent; Vallet, Valerie; Sánchez Marcos, Enrique; Química Física; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; European Union (UE)
Accurately predicting spectra for heavy elements, often open-shell systems, is a significant challenge typically addressed using a single cluster approach with a fixed Coordination number. Developing a realistic model that accounts for temperatura effects, variable coordination numbers, and interprets experimental data is even more demanding due to the strong solute-solvent interactions present in solutions of heavy metal cations. This study addresses these challenges by combining multiple methodologies to accurately predict realistic spectra for highly-charged metal cations in aqueous media, with a focus on the electronic absorption spectrum of Ce3+ in water. Utilizing highly correlated relativistic quantum mechanical (QM) wavefunctions and structures from molecular dynamics (MD) simulations, we show that the convolution of individual vertical transitions yields an excellent agreement with experimental results without the introduction of empirical broadening. The good results are obtained for both the normalized spectrum and that of absolute intensity. The study incorporates a statistical machine learning algorithm, Gaussian Mixture Models-Nuclear Ensemble Approach (GMM-NEA), to convolute individual spectra. The microscopic distribution provided by MD simulations allows us to examine the contributions of the octa-andennea-hydrateof Ce3+ in wáter to the final spectrum. Additionally, the temperatura dependence of thes pectrum is theoretically captured by observing the changing population of these hydrate form swith temperature. We also explore an alternative method for obtaining statistically representative structures in a less demanding manner tan MD simulations, derived from QM Wigner distributions. The combination of Wigner-sampling and GMM-NEA broadening shows promise for wide application in spectroscopic analysis and predictions, offering a computationally efficient alternative to traditional methods.
Acetonitrile Real Gas Phase Behavior from quasi-ideal gas to nanodroplets: A Microscopical View
(American Institute of Physics, 2024) Martínez Fernández, José Manuel; Hernández Cobos, Jorge; Rodríguez Pappalardo, Rafael; Sánchez Marcos, Enrique; Química Física; European Union (UE); Junta de Andalucía; Universidad de Sevilla; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España
We have applied a recently developed general purpose acetonitrile force field based on first-principles calculations to simulate acetonitrile in gas phase at different tem- peratures and densities. These conditions range from nearly-ideal to real gas phase behavior and condensation. The MD simulation results agree fairly well with the experimental studies available in the literature on the gas samples. The structural analysis of aggregates and their associated interaction energies is examined and re-lated to the early model proposed on molecular association and equilibrium deter- mining the non-ideal behavior. The formation of dimers is the main responsible for the non-ideal behavior of the gas at very low density, confirming suggested models based on previous experimental studies. However, when the density of the sample rises, the level of aggregation increases and the simple concept of dimerization does not hold anymore. The real behavior adopted by the gas is related to the distribution of molecular structures observed. The view of a real gas as a generic interparticle interaction system without a defined form may then be rationalized on the basis of a defined molecular association originated by a distribution of aggregates at the low density regime. The simple witht hehighest density (∼ 1.4 × 103 molm−3) at the lowest temperatura exhibits a massive aggregation where most of ACN molecules in the simulation box form a big cluster. Its radial distribution function is similar to that of the liquid ACN. This strongly inhomogeneous distribution in the box can be considered a condensation in gas phase under specific density-T conditions. This formation opens the door to the potential tuning of its solvent properties as a function of its size in these nanodroplets that in turn are controlled by the density-T conditions.

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