Person: Segura Castedo, José Luis
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First Name
José Luis
Last Name
Segura Castedo
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Química Orgánica
Area
Química Orgánica
Identifiers
18 results
Search Results
Now showing 1 - 10 of 18
Item Turn‐On Solid‐State Fluorescent Determination of Zinc Ion by Quinoline‐Based Covalent Organic Framework(Macromolecular Rapid Communications, 2024) García Arroyo, Paloma; Gala Sánchez, Elena; Martínez‐Fernández, Marcos; Elena Salagre; José I. Martínez; Enrique G. Michel; Segura Castedo, José LuisAbstractA new quinoline‐based COF (covalent organic framework), obtained by Povarov reaction, containing 2,6‐diisopropylphenyl moieties as substituents over the heterocyclic ring is described for detecting Zn2+ in aqueous solution. The introduction of the mentioned bulky phenyl rings into the network favors an increase of the distance between the reticular sheets and their arrangement, obtaining a new material with an alternating AB type stacking. The new material exhibits good selectivity to detect Zn2+ by fluorescence emission in aqueous solutions up to a concentration of 1.2 × 10−4 m of the metal ion. In order to have a deeper insight into the interaction between the COF and the zinc cation, a thorough spectroscopical, microscopical, and theoretical study is also presented and discussed in this communication.Item Oligothiophene-Naphthalimide Hybrids Connected through Rigid and Conjugated Linkers in Organic Electronics: An Overview(electronic materials, 2021) Alonso-Navarro, Matías J; Gala, Elena; Ramos, M.Mar; Ponce Ortiz, Rocío; Segura Castedo, José LuisIn this article, we summarize the synthetic approaches developed in our research groups during the last decade to efficiently tune the optical, electrochemical and morphological characteristics of oligothiophene–naphthalimide assemblies. Different variables were tuned in these organic semiconductors, such as the planarity and the length of their π-conjugated backbones, the topology and energy levels of the frontier molecular orbitals (HOMO and LUMO) and their molecular dipole moments. The tuning of these properties can be connected with the microstructure properties observed by atomic force microscopy (AFM) and X-ray diffraction (XRD) in thin films as well as with the performances in organic field-effect transistors (OFETs). The possibility of incorporating these donor-acceptor assemblies into macromolecular structures is also addressed, and some innovative applications for these macromolecular systems, such as the degradation of organic pollutants in aqueous media, are also presented.Item Exploring advanced oxygen reduction reaction electrocatalysts: the potential of metal‐free and non‐pyrolyzed covalent organic frameworks(ChemSusChem, 2024) Martínez‐Fernández, Marcos; Segura Castedo, José LuisOxygen reduction reaction (ORR) electrocatalysis is an area of increasing interest for the in‐situ production of H2O2 or the development of energy‐related devices such as hydrogen fuel cells. Although pyrolyzed catalysts still offer the best performances to date with reference to the organic‐based catalysts, metal‐free and non‐pyrolyzed covalent organic frameworks (COFs) stands out as promising alternatives candidates due to their favourable characteristics such as crystallinity, porosity, and organic composition, allowing the study of structural‐property relationships. Herein, we present the design principles and recent advances in COFs‐based ORR electrocatalysts, demonstrating how composition influences the activity and electronic pathway of the oxygen reduction process.Item Plasticized poly(lactic acid) reinforced with antioxidant covalent organic frameworks (COFs) as novel nanofillers designed for non-migrating active packaging applications(Polymer, 2020) Arrieta, Marina P.; García-García, Daniel; Fombuena, Vicent; Mancheño, María J.; García Arroyo, Paloma; Cuervo Rodríguez, María Rocío; Segura Castedo, José LuisA 2D Covalent Organic Framework (named [HC≡C]0.5-TPB-DMTP-COF) was synthesized and post synthetically functionalized with dopamine via Copper-catalyzed azide–alkyne cycloaddition (CuAAC) reaction (COFDOPA) to obtain 2D nanoparticles with antioxidant activity. COFDOPA nanoparticles were exfoliated into nanosheets (COFDOPA-e) and incorporated into plasticized poly(lactic acid) (PLA) matrix with 15 wt% of acetyl trybutyl citrate (ATBC) to develop non-migratory sustainable packaging. The effect of COFDOPA and exfoliated COFDOPA-e (in 0.5, 1 and 3 wt%) on the structural, thermal and mechanical properties of PLA-ATBC was studied. The bionanocomposites loaded with low amounts of COFDOPA-e (0.5 wt% and 1 wt%) resulted optically transparent and showed good interfacial adhesion, increased crystallinity, thermal and mechanical performance. Moreover, the overall migration level assayed in a fatty food simulant was below the migration limits required for food packaging materials and showed effective antioxidant activity. Thus, these bionanocomposites show great potential as non-migration antioxidant materials with interest in the sustainable food packaging field.Item Robust Amide‐Linked Fluorinated Covalent Organic Framework for Long‐Term Oxygen Reduction Reaction Electrocatalysis(2024) Jiménez‐Duro, Miguel; Martínez‐Periñán, Emiliano; Martínez‐Fernández, Marcos; Martínez, José I.; Lorenzo, Encarnación; Segura Castedo, José LuisAbstractThe high energy demand of the evolving world opens the door to develop more sustainable and environmentally friendly energy sources. Oxygen reduction reaction (ORR) is a promising candidate, being the 2e− pathway of great interest for the green production of hydrogen peroxide. Metal‐free covalent organic frameworks (COFs) electrocatalysts present a suitable alternative to substitute the noble‐metals more commonly employed in this application. However, the lability of the linkages building up the framework raises an issue for their long‐term use and application in aggressive media. Herein, a stable amide‐linked COF is reported through post‐synthetic modification of a previously reported imine‐linked COF proven to be effective as an electrocatalyst, enhancing its chemical stability and electrochemical response. It is found that after the linkage transformation, the new electrocatalyst displays a higher selectivity toward the H2O2 production (98.5%) and an enhanced turnover frequency of 0.155 s−1, which is among the bests reported to date for metal‐free and COF based electrocatalysts. The results represent a promising step forward for metal‐free non pyrolyzed electrocatalysts, improving their properties through post‐synthetic linkage modification for long‐term operation.Item Scalable Synthesis and Electrocatalytic Performance of Highly Fluorinated Covalent Organic Frameworks for Oxygen Reduction(Angewandte Chemie International Edition, 2023) Martínez‐Fernández, Marcos; Martínez‐Periñán, Emiliano; Peña Ruigómez, Alejandro de la; Cabrera Trujillo, Jorge Juan; Navarro, Jorge A.R.; Aguilar‐Galindo, Fernando; Rodríguez‐San‐Miguel, David; Ramos, Mar; Vismara,Rebecca; Zamora, Félix; Lorenzo, Encarnación; Segura Castedo, José LuisIn this study, we present a novel approach for the synthesis of covalent organic frameworks (COFs) that overcomes the common limitations of non-scalable solvothermal procedures. Our method allows for the room-temperature and scalable synthesis of a highly fluorinated DFTAPB-TFTA-COF, which exhibits intrinsic hydrophobicity. We used DFT-based calculations to elucidate the role of the fluorine atoms in enhancing the crystallinity of the material through corrugation effects, resulting in maximized interlayer interactions, as disclosed both from PXRD structural resolution and theoretical simulations. We further investigated the electrocatalytic properties of this material towards the oxygen reduction reaction (ORR). Our results show that the fluorinated COF produces hydrogen peroxide selectively with low overpotential (0.062 V) and high turnover frequency (0.0757 s-1 ) without the addition of any conductive additives. These values are among the best reported for non-pyrolyzed and metal-free electrocatalysts. Finally, we employed DFT-based calculations to analyse the reaction mechanism, highlighting the crucial role of the fluorine atom in the active site assembly. Our findings shed light on the potential of fluorinated COFs as promising electrocatalysts for the ORR, as well as their potential applications in other fields.Item High‐Throughput Screening of Low‐Bandgap Organic Semiconductors for Photovoltaic Applications: In the Search of Correlations(Solar RRL, 2024) Torimtubun, Abat Amelenan; Alonso‐Navarro, Matías J.; Quesada‐Ramírez, Arianna; Rodríguez‐Martínez, Xabier; Segura Castedo, José Luis; Goñi, Alejandro R.; Campoy‐Quiles, MarianoLow‐bandgap nonfullerene acceptors (NFAs) offer a unique potential for photovoltaic (PV) applications, such as transparent PV and agrivoltaics. Evaluating each new PV system to achieve the optimum thickness, microstructure, and device performance is, however, a complex multiparametric challenge with large time and resource requirements. Herein, the PV potential of low‐bandgap donor and NFA materials by combining high‐throughput screening and statistical methods is evaluated. The use of thickness gradients (20–600 nm) facilitates the fabrication of more than 2000 doctor‐bladed devices from 24 different low‐bandgap blend combinations. The corresponding power conversion efficiencies varies significantly, from 0.06% to 10.45% across materials and thicknesses. The self‐consistency of the large dataset allows to perform a parameter sensitivity study as well as parameter correlation analysis. These reveal that the choice of materials and energy alignment‐related features (i.e., electron affinity offset, ionization energy offset, bandgap, and energy loss) has the largest influence on final device performance, while processing conditions appear less important for the final efficiencies. Our study demonstrates that high‐throughput experimentation is a perfect match for correlation analyses in order to gain a statistically meaningful understanding of these systems, potentially accelerating the discovery of new materials.Item Scalable synthesis and electrocatalytic performance of highly fluorinated covalent organic frameworks for oxygen reduction(Angewandte Chemie International Edition, 2023) Martínez‐Fernández, Marcos; Martínez‐Periñán, Emiliano; Peña Ruigómez, Alejandro de la; Cabrera Trujillo, Jorge Juan; R. Navarro, Jorge A.; Aguilar Galindo, Fernando; Rodríguez‐San‐Miguel, David; Ramos, Mar; Vismara, Rebecca; Félix Zamora; Lorenzo, Encarnación; Segura Castedo, José LuisAbstract In this study, we present a novel approach for the synthesis of covalent organic frameworks (COFs) that overcomes the common limitations of non‐scalable solvothermal procedures. Our method allows for the room‐temperature and scalable synthesis of a highly fluorinated DFTAPB‐TFTA‐COF, which exhibits intrinsic hydrophobicity. We used DFT‐based calculations to elucidate the role of the fluorine atoms in enhancing the crystallinity of the material through corrugation effects, resulting in maximized interlayer interactions, as disclosed both from PXRD structural resolution and theoretical simulations. We further investigated the electrocatalytic properties of this material towards the oxygen reduction reaction (ORR). Our results show that the fluorinated COF produces hydrogen peroxide selectively with low overpotential (0.062 V) and high turnover frequency (0.0757 s−1) without the addition of any conductive additives. These values are among the best reported for non‐pyrolyzed and metal‐free electrocatalysts. Finally, we employed DFT‐based calculations to analyse the reaction mechanism, highlighting the crucial role of the fluorine atom in the active site assembly. Our findings shed light on the potential of fluorinated COFs as promising electrocatalysts for the ORR, as well as their potential applications in other fields.Item V-Shaped tröger oligothiophenes boost triplet formation by CT mediation and symmetry breaking(Journal of the American Chemical Society, 2023) Medina Rivero, Samara; Alonso-Navarro, Matías J.; Tonnelé, Claire; Marín-Beloqui, Jose M.; Suárez-Blas, Fátima; Clarke, Tracey M.; Kang, Seongsoo; Oh, Juwon; M. Mar Ramos; Kim, Dongho; Casanova, David; Casado, Juan; Segura Castedo, José LuisA new family of molecules obtained by coupling Tröger’s base unit with dicyanovinylene-terminated oligothiophenes of different lengths has been synthesized and characterized by steady-state stationary and transient timeresolved spectroscopies. Quantum chemical calculations allow us to interpret and recognize the properties of the stationary excited states as well as the timedependent mechanisms of singlet-to-triplet coupling. The presence of the diazocine unit in Tröger’s base derivatives is key to efficiently producing singletto-triplet intersystem crossing mediated by the role of the nitrogen atoms and of the almost orthogonal disposition of the two thiophene arms. Spin−orbit coupling-mediated interstate intersystem crossing (ISC) is activated by a symmetry-breaking process in the first singlet excited state with partial charge transfer character. This mechanism is a characteristic of these molecular triads since the independent dicyanovinylene-oligothiophene branches do not display appreciable ISC. These results show how Tröger’s base coupling of organic chromophores can be used to improve the ISC efficiency and tune their photophysics.Item Electrochemical (Bio)Sensors Based on Covalent Organic Frameworks (COFs)(Sensors, 2022) Martínez-Periñán, Emiliano; Martínez-Fernández, Marcos; Segura Castedo, José Luis; Lorenzo, EncarnaciónCovalent organic frameworks (COFs) are defined as crystalline organic polymers with programmable topological architectures using properly predesigned building blocks precursors. Since the development of the first COF in 2005, many works are emerging using this kind of material for different applications, such as the development of electrochemical sensors and biosensors. COF shows superb characteristics, such as tuneable pore size and structure, permanent porosity, high surface area, thermal stability, and low density. Apart from these special properties, COF’s electrochemical behaviour can be modulated using electroactive building blocks. Furthermore, the great variety of functional groups that can be inserted in their structures makes them interesting materials to be conjugated with biological recognition elements, such as antibodies, enzymes, DNA probe, aptamer, etc. Moreover, the possibility of linking them with other special nanomaterials opens a wide range of possibilities to develop new electrochemical sensors and biosensors.