Fabricación y caracterización de materiales nanoestructurados para la construcción de dispositivos basados en carbono

En este trabajo de fin de grado se han fabricado monocapas orgánicas formando sales de diazonio in situ a partir de la correspondiente amina. Mediante la técnica de electrografting se han creado enlaces covalentes C-C entre la molécula que actúa a modo de hilo molecular y el electrodo inferior de naturaleza carbonosa (PEDOT:PSS), formándose películas de espesor monomolecular. Para la caracterización de estos dispositivos se ha empleado la voltametría cíclica y la microscopía de fuerza atómica (AFM). Como último paso en la construcción de dispositivos totalmente orgánicos se ha depositado un electrodo superior de carbono amorfo mediante la técnica FEBID (Focused Electron Beam Induced Deposition). Estos experimentos se han realizado usando un sustrato base flexible, pero se ha encontrado que los soportes poliméricos como el Mylar no son capaces de resistir el haz de electrones del FEBID, que resulta en un calentamiento de la muestra y debido a su baja conductividad térmica el dispositivo se deforma. Esto abre la búsqueda a utilizar sustratos flexibles pero con una mayor conductividad térmica. <br /

A genuine germylene PGeP pincer ligand for formic acid dehydrogenation with iridium

We report an iridium system constructed around a long-tethered PGeP ligand that facilitates access to the less common germylene form, so far unreported for an 'NHC-type' Ge ligand. Its bonding is substantiated by computational studies and we have demonstrated its use for the catalytic dehydrogenation of formic acid, highlighting the potential of this underdeveloped type of ligand.This work has been supported by the European Research Council (ERC Starting Grant, CoopCat, 756575). We also thank grants PID2019-110856GA-I00 (MCIN/AEI/10.13039/501100011033) and TED2021-132225B-I00/AEI/10.13039/501100011033/by Unión Europea NextGenerationEU/PRTR, Junta de Andalucía (P18-FR-4688) and the use of CESGA computational facilities.Peer reviewe

Supporting Information. A Genuine Germylene PGeP Pincer Ligand for Formic Acid Dehydrogenation with Iridium

1. General considerations.-- 2. Synthesis and characterization of new compounds.-- 3. NMR spectra of new compounds.-- 4. Crystal structure determinations.-- 5. TON and TOF determination.-- 6. Computational studies.-- 7. References.Peer reviewe

Dehydrogenation of formic acid using iridium-NSi species as catalyst precursors

Using a low loading of the iridium(III) complexes [Ir(CF3SO3)(κ2-NSiiPr)2] (1) (NSiiPr = (4-methylpyridin-2-yloxy)diisopropylsilyl) and [{Ir(κ2-NSiMe)2}2(μ-CF3SO3)2] (2) (NSiMe = (4-methylpyridin-2-yloxy)dimethylsilyl) in the presence of Et3N, it has been possible to achieve the solventless selective dehydrogenation of formic acid. The best catalytic performance (TOF5 min ≈ 2900 h−1) has been achieved with 2 (0.1 mol%) and Et3N (40 mol% to FA) at 373 K. Kinetic studies at variable temperatures show that the activation energy of the 2-catalyzed process at 353 K is 22.8 ± 0.8 kcal mol−1. KIE values of 1.33, 2.86, and 3.33 were obtained for the 2-catalyzed dehydrogenation of HCOOD, DCOOH, and DCOOD, respectively, in the presence of 10 mol% of Et3N at 353 K. These data show that the activation of the C–H bond of FA is the rate-determining step of the process. A DFT mechanistic study for the catalytic cycle involving hydride abstraction from the formate anion by the metal, assisted by a molecule of formic acid, and heterolytic H2 formation has been performed. Moreover, the presence of Ir-formate intermediates was identified by means of NMR studies of the catalytic reactions in thf-d8 at 323 K. In all the cases, the decomposition of the catalyst to give unactive crystalline iridium NPs was observed.The financial support from projects PGC2018-099383-B-I00 (MCIU/AEI/FEDER, UE), RTI2018-099136-A-I00 (MCIU/AEI/FEDER, UE), CSIC project 202080I024 and DGA/FSE project E42_20R is gratefully acknowledged. A. U. thankfully acknowledges the Spanish MECD for a FPU fellowship (FPU 2017/05417).Peer reviewe

Deep-sequencing reveals broad subtype-specific HCV resistance mutations associated with treatment failure.

A percentage of hepatitis C virus (HCV)-infected patients fail direct acting antiviral (DAA)-based treatment regimens, often because of drug resistance-associated substitutions (RAS). The aim of this study was to characterize the resistance profile of a large cohort of patients failing DAA-based treatments, and investigate the relationship between HCV subtype and failure, as an aid to optimizing management of these patients. A new, standardized HCV-RAS testing protocol based on deep sequencing was designed and applied to 220 previously subtyped samples from patients failing DAA treatment, collected in 39 Spanish hospitals. The majority had received DAA-based interferon (IFN) α-free regimens; 79% had failed sofosbuvir-containing therapy. Genomic regions encoding the nonstructural protein (NS) 3, NS5A, and NS5B (DAA target regions) were analyzed using subtype-specific primers. Viral subtype distribution was as follows: genotype (G) 1, 62.7%; G3a, 21.4%; G4d, 12.3%; G2, 1.8%; and mixed infections 1.8%. Overall, 88.6% of patients carried at least 1 RAS, and 19% carried RAS at frequencies below 20% in the mutant spectrum. There were no differences in RAS selection between treatments with and without ribavirin. Regardless of the treatment received, each HCV subtype showed specific types of RAS. Of note, no RAS were detected in the target proteins of 18.6% of patients failing treatment, and 30.4% of patients had RAS in proteins that were not targets of the inhibitors they received. HCV patients failing DAA therapy showed a high diversity of RAS. Ribavirin use did not influence the type or number of RAS at failure. The subtype-specific pattern of RAS emergence underscores the importance of accurate HCV subtyping. The frequency of "extra-target" RAS suggests the need for RAS screening in all three DAA target regions