Examinando por Autor "Ramos, María Mar"

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BODIPY doping of Covalent Organic Frameworks-based nanomaterials: a novel strategy towards biomedical applications
(Elsevier, 2023-07-24) Suárez-Blas, Fatima; Martínez-Fernández, Marcos; Prieto-Castañeda, Alejandro; García-Fernández, Alba; Martínez, José I.; Ramos, María Mar; Ortíz, Maria J.; Martínez-Máñez, Ramón; Segura, José L.
Covalent organic Frameworks (COFs) are a class of crystalline macromolecular materials build-up by monomers with specific symmetries or functionalities. There are important limitations in the synthesis of highly ordered COFs, such as the shape and packing of the building blocks. Thus, the presence of fluorine atoms that lie perpendicular to the bisecting plane of BODIPY derivatives together with the presence of four bulky methyl groups could hinder the crystallization process in COF synthesis. For that reason, BODIPY-based COFs are rarely incorporated to COF networks. In this work, following the mixed linker strategy, a pre-synthetic method to dope COF structures with BODIPY units was developed. The materials have been processed into fluorescent Covalent Organic Nanosheets (CONs) with defined particle-size distributions around 100 nm, suitable for cellular biomedical applications. The viability of the CONs was evaluated using Sk-Mel-103 cells, demonstrating the internalization showing 100% cell viability. We envisage that this work could accelerate the discovery of new COF-based materials for biomedical sciences.
Naphthalimide-Based 3D Organic Semiconductors: Synthesis and Application as Photo-Electrocatalysts for Organic Dyes Degradation and Water Splitting
(Wiley-VCH GmbH, 2023) Suárez-Blas, Fátima; Junyi, Li; Alonso-Navarro, Matías J.; Harbuzaru, Alejandra; Ponce Ortíz, Rocío; Ramos, María Mar; Shalom, Menny; Barrio, Jesús; Segura, José L.
1,2-diketone-based naphthalimide has emerged as an important electronwithdrawing building block in the synthesis of organic semiconductor assemblies for a wide range of applications. The reaction with different diamine derivatives enables the formation of pyrazine linkers which promotes planarity and rigidity of the naphthalimide-based semiconductors, therefore tunning their electronic structure and processability. Despite the significant use of this versatile building block to generate flat and rigid assemblies, the correlation between rigidity and dimensionality in these systems and their photocatalytic activity remains unexplored so far. Herein, with the aim to modulate the photocatalytic activity of these materials, a new family of assemblies with different dimensionality end-capped with naphthalimide moieties are developed in which one (NIPB), three (3NIPT), and four (4NIPTM) units have been selectively introduced. The good processability of these novel semiconductors combined with their suitable energy levels allows their application as photo-electrocatalysts for the degradation of organic dyes and for water splitting. The derivative with the highest dimensionality, 4NIPTM, shows higher photo-electrocatalytic activity and lower charge transfer resistance than that of conventional semiconductors (such as TiO2 and C3N4), reaching photocurrents up to 20 mA cm−2.
Novel synthetic approaches towards hexaazatriphenylene (HAT) derivatives
(Universidad Rey Juan Carlos-Universidad Complutense, 2008) Juárez, Rafael; Ramos, María Mar; Segura, José Luis
Large two-dimensional molecules with extended ¿-systems are subject of increasing interest as a consequence of their technological applications. In particular, hexaazatriphenylene (HAT) derivatives, present a great interest due to the influence of heteroatoms on the electronic nature without modifying the structure. HAT derivatives have recently attracted attention as materials for organic electronic applications1 and depending on the choice of substituent can have a variety of applications (discotic liquid-crystals, n-type semiconducting, magnetic materials or fluorescent dyes).2 Whereas HATs carrying six identical substituents are well known following different synthetic approaches, the synthesis of non-centrosymmetric HAT derivatives is still quite rare. In our working group we are centered in two main routes for affording HAT derivatives. One route affords a variety of symmetrical HAT derivatives including HAT condensed systems. On the other hand, we have also synthesized non-centrosymetric ¿-conjugated donor-acceptor molecules bearing a HAT core and donor groups in the periphery.3 In this communication we present a new soluble ¿-deficcient derivative which consists of three HAT molecules condensed around a central aromatic core so we have named it triHAT. We have found triHAT to be 0.75 V better acceptor than HAT in itself. We also present a new synthetic route in order to obtain non-centrosymetric ¿-conjugated donor-acceptor molecules bearing a HAT core and donnor groups in the periphery. This synthesis paves the way for further conjugated donnor-acceptor derivatives of HAT.