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
26 results
Search Results
Now showing 1 - 10 of 26
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 Catalytically Active Imine-based Covalent Organic Frameworks for Detoxification of Nerve Agent Simulants in Aqueous Media(Materials, 2019) Royuela, Sergio; Gil-San Millán, Rodrigo; Mancheño Real, María José; Ramos, M. Mar; Segura Castedo, José Luis; Navarro, Jorge A. R.; Zamora, FélixA series of imine-based covalent organic frameworks decorated in their cavities with different alkynyl, pyrrolidine, and N-methylpyrrolidine functional groups have been synthetized. These materials exhibit catalytic activity in aqueous media for the hydrolytic detoxification of nerve agents, as exemplified with nerve gas simulant diisopropylfluorophosphate (DIFP). These preliminary results suggest imine-based covalent organic frameworks (COFs) as promising materials for detoxification of highly toxic molecules.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 Síntesis y estudio electroquímico y estructural de Complejos de Transferencia de Carga Inter e Intramoleculares(2002) Segura Castedo, José Luis; Seoane Prado, Carlos; Martín León, NazarioEn la presente memoria se describe la síntesis, estudio electroquímico y estudio estructural de complejos de transferencia de carga ínter- e intramoleculares. En la primera parte de esta memoria se estudia el efecto del aumento de la conjugación y de los sustituyentes sobre la capacidad aceptora de distintos derivados de diciano-p-quinodiimina (dcnqi). Esta primera parte de la tesis doctoral concluye con el estudio de la formación de complejos de transferencia de carga con ttf (tetratiafulvaleno) y sales anion-radical-cobre de algunos de estos derivados de dcnqi. En la segunda parte, se aborda el diseño de un prototipo de molécula que contiene en su estructura una subunidad estructural deficiente en electrones (aceptora) y una subunidad estructural rica en electrones (dadora). El estudio de las propiedades electroquímicas y estructurales de estos nuevos sistemas se ha completado con las medidas de conductividad eléctrica así como mediante cálculos teóricos semiempíricos.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 Rigid dendritic donor-acceptor ensembles: Control over energy and electron transduction(Journal of the American Chemical Society, 2002) Guldi, Dirk; Swartz, Angela; Luo, Chuping; Gómez Aspe, Rafael; Segura Castedo, José Luis; Martín León, NazarioSeveral generations of phenylenevinylene dendrons, covalently attached to a C60 core, have been developed as synthetic model systems with hierarchical, fine-tuned architectures. End-capping of these dendritic spacers with dibutylaniline or dodecyloxynaphthalene, as antennas/electron donors, yielded new donor-bridge-acceptor ensembles in which one, two, or four donors are allocated at the peripheral positions of the well-defined dendrons, while the electron accepting fullerene is placed at the focal point of the dendron. On the basis of our cyclic voltammetry experiments, which disclose a single anodic oxidation and several cathodic reduction processes, we rule out significant, long-range couplings between the fullerene core and the end-standing donors in their ground-state configuration. Photophysical investigations, on the other hand, show that upon photoexcitation an efficient and rapid transfer of singlet excited-state energy (6 × 1010 to 2.5 × 1012 s-1) controls the reactivity of the initially excited antenna portion. Spectroscopic and kinetic evidence suggests that yet a second contribution, that is, an intramolecular electron-transfer, exists, affording C60.--dendron.+ with quantum yields (Φ) as high as 0.76 and lifetimes (τ) that are on the order of hundreds of nanoseconds (220-725 ns). Variation of the energy gap modulates the interplay of these two pathways (i.e., competition or sequence between energy and electron transfer).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 Synthesis and electropolymerization of a perylenebisimide-functionalized 3,4-ethylenedioxythiophene (EDOT) derivative(Organic Letters, 2005) Segura Castedo, José Luis; Gómez Aspe, Rafael; Reinold, Egon; Bauërle, PeterWe have developed a convenient and straightforward procedure for the preparation of functionalized 3,4-ethylenedioxythiophene (EDOT) systems by using a new chloromethyl-EDOT derivative as a versatile synthon. Based on this procedure, novel suitably functionalized perylenetetracarboxylic diimide (PDI) dye derivatives covalently linked to 3,4-ethylenedioxythiophene moieties have been synthesized and electrochemically polymerized to yield a donor-acceptor PEDOT derivative with an enhanced absorption cross-section
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