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
5 results
Search Results
Now showing 1 - 5 of 5
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 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 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 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.