Diseño y caracterización de nuevos sistemas fluorescentes para su utilización como interruptores y puertas lógicas moleculares : implicación de procesos de transferencia electrónica y de energía en el estado excitado

La investigación de interruptores moleculares fotoactivos y/o fluorescentes es un campo de la química con intensa actividad en todo el mundo. Esta tesis doctoral contribuye a estas actividades con el diseño y la caracterización de nuevos interruptores moleculares y sistemas modelo que pueden ser usados para el estudio de procesos de transferencia de energía. En detalle, se han realizado trabajos en tres bloques temáticos principalmente: (i) el uso de química supramolecular para la realización de funciones reversibles y con posibilidad de resef en agua, (¡i) la implementación de compuestos fotocrómicos como unidades centrales de interruptores con la capacidad de reproducir lógicas moleculares secuenciales (keypad locks moleculares e interruptores moleculares), y (iii) la investigación de procesos de transferencia de energía en diadas contenedoras de moléculas fulereno y BODIPY con aplicación potencial en estructuras celulares fotovoltaicas y biológicas (estudio de imágenes). Se usó un complejo huésped-anfitrión entre el macrociclo orgánico cucurbit[7]urilo y una sonda con fluorescencia dependiente del pH naftalimida-benzimidazol para demostrar el control inducido por el macrociclo de una transferencia electrónica fotoinducida en el huésped. La señal de fluorescencia dependiente de este input se aplicó para la implementación de operaciones lógicas supramoleculares como INHIBIT, AND o ÑOR. Como ventaja adicional las funciones lógicas pueden ser reconfiguradas y tienen la posibilidad de reset, lo cuál, lo convierte al sistema en una plataforma versátil para el procesamiento de información molecular. Todas las operaciones fueron hechas en agua y son potencialmente aplicables en contextos biomédicos. Se investigaron interruptores moleculares fotocrómicos (espiropiranos anexados a fluoróforos y una fulgimida) que pueden dar distintas respuestas fluorescentes dependiendo de sus estados con el anillo cerrado o abierto. Se desarrolló y demostró un keypad lock molecular y un dispositivo de memoria D-latch basados en una caracterización fotoquímica y fotofísica detallada. Estos dispositivos lógicos moleculares, publicados en pocas ocasiones, dependen no sólo de la aplicación del input adecuado (especies químicas o de luz a distintas longitudes de onda), sino que también lo hacen del orden de aplicación. Estos interruptores no son triviales y su investigación desarrollada está, sin duda, en primera línea del procesamiento e información molecular. Algunos de los interruptores fotocrómicos mencionados relevan en procesos en el estado excitado de transferencia de energía. Hay un interés constante en el uso de transferencias de energía como principio para diseñar diadas moleculares con las funciones más diversas. En esta tesis se han investigado varias diadas aminonaftalimida-fulereno que han demostrado tener una transferencia de energía cuantitativa. De este modo, los sistemas emulan funciones donde la energía de excitación está canalizada al fulereno (C60 or C70). Estas formas alotrópicas de carbono han tenido mucha atención en referencia a sus usos en sistemas fotovoltáicos y, en este contexto, los estudios realizados proporcionan conocimientos interesantes sobre aspectos mecanísticos y fotofísicos que los hacen potencialmente interesantes para su aplicación. El otro tipo de diadas con energía de transfencia utilizadas tienen una aminonaftalimida como donador de energía y un colorante BODIPY como aceptar. Esta clase de colorantes encuentra amplio uso como sensores y sondas en la investigación bio-relacionada, entre ellos imágenes de microscopía confocal de fluorescencia. Con el fin de aumentar el desplazamiento de Stokes inherentemente pequeña del colorante BODIPY un cromóforo de la antena se puede utilizar que transfiere su energía de excitación al tinte aceptar. Se demostró que la transferencia de energía, que se puede observar en estas diadas investigadas aminonaftalimida-BODIPY, era altamente eficiente. Una característica especial de la transferencia de energía en estas diadas es que no sólo funciona bajo condiciones de excitación a un fotón, sino también lo hace en el régimen de absorción no lineal de dos fotones. Esto amplía en gran medida el potencial de aplicación de los colorantes BODIPY en el estudio de imágenes biológicas. Esto, incluso, se ha demostrado en un estudio modelo por medio de la obtención de imágenes de células HeLa. Como declaración global puede resumirse que en la tesis presente se ha mostrado que el control de los procesos en el estado excitado, tales como la transferencia electrónica fotoinducida y la transferencia de energía se pueden utilizar en una amplia gama de aplicaciones que van desde el procesamiento de la información molecular hasta sistemas fotovoltáicos e imágenes biológicas.The investigation of photoactive and/or fluorescent molecular switches is a field of chemical research with intensive worldwide activities. This doctoral thesis contributes to these activities with the design and characterization of new molecular switches and model systems that can be used to study energy transfer processes. In detail works in three thematic blocks have been realized: (i) use of supramolecular chemistry for the realization of reversible and resettable logic functions in water, (ii) implementation of photochromic compounds as central units of switches with the capacity of sequential molecular logic (molecular keypad locks and memory switches), and (iii) investigation of energy transfer processes with fullerene- or BODIPY-containing molecular dyads and their potential application in photovoltaics and for bioimaging of cellular structures. An host-guest complex between the cucurbit[7]uril organic macrocycle and a pH-dependent fluorescent naphthalimide-benzimidazole guest were used to demonstrate the macrocycle-induced control of photoinduced electron transfer of the guest. The resulting input-dependent fluorescence signal was applied for the demonstration of supramolecular logic operations including INHIBIT, AND or NOR. As an additional advantage the logic functions can be reset and reconfigured, which makes the system a versatile platform for molecular information processing. All operations were done in water and can be potentially applied in biomimetic contexts. Photochromic molecular switches (fluorophore-appended spiropyrans and a fulgimide) that can deliver distinct fluorescence responses depending on their ring-open and ring-closed states were investigated. Based on the detailed photochemical and photophysical characterization a molecular keypad lock and a D-latch memory device were developed and demonstrated. These rarely reported molecular logic devices depend not only on the aDolication of the “riaht” inDut information (chemical sDecies or liaht inDuts of varvina wavelenathsV but also on the relative order of the input application. Such switches are not trivial and the developed research is without doubt at the frontline of these recent developments in molecular information processing. Some of the mentioned photochromic switches rely on energy transfer as excited state process. There is a constant interest of using energy transfer as design principle for molecular dyads with the most diverse functions. Herein several aminonaphthalimide-fullerene dyads were investigated and quantitative energy transfer was shown. Thus, the systems emulate antenna functions where the excitation energy is canalized to the fullerene (C60 or C70). These allotropic carbon forms have found much attention for their use in photovoltaic systems and in this context the undertaken studies provide interesting mechanistic and photophysical insights that are combined with a potential for applications. The other type of energy transfer dyads used again an aminonaphthalimide as energy donor and a BODIPY dye as acceptor. This class of dyes finds widespread use as sensors and probes in bio-related research, among them fluorescence confocal microscopy imaging. In order to increase the inherently small Stokes shift of the BODIPY dye an antenna chromophore can be used that transfers its excitation energy to the acceptor dye. In this thesis it was shown that highly efficient energy transfer can be observed in the investigated aminonaphthalimide-BODIPY dyads. As a special twist the energy transfer works not only under conditions of one-photon excitation but also in the non-linear two-photon absorption regime. This extends the application potential of BODIPY dyes in bioimaging tremendously. In a model study this has been demonstrated for the imaging of HeLa cells. In global statement it can be summarized that in the presented thesis that the control of excited state processes such as photoinduced electron transfer and energy transfer can be used for a wide spectrum of applications ranging from molecular information processing to photovoltaics and bioimaging

Flipped Classroom Teaching in Organic Chemistry in the Context of CLIL

This paper proposes an experience that involves the methodological model of the flipped classroom with the introduction of foreign language teaching, to promote the acquisition of transversal and linguistic skills in three subjects of the Degree in Chemistry at the University of Huelva (Spain). This proposal includes the implementation of this methodology in different didactic units of each one of the subjects. The method is developed in 4 different phases, starting with the programming of the experience; elaboration of the teaching material for its development, based on the autonomous work of the students; to the classroom work and resolution of doubts that take place in the classroom. The implementation of this teachinglearning experience has been globally successful

Photofunctional Scope of Fluorescent Dithienylethene Conjugates with Aza-Heteroaromatic Cations

A series of dithienylethene (DTE) photoswitches with aza-heteroaromatic cationic moieties is synthesized. The switches are characterized regarding their photochemical and photophysical properties in acetonitrile and in water. The efficiency of the switching and the photostationary state composition depend on the degree of π-conjugation of the heteroaromatic systems. Thus, DTEs with acridinium-derived moieties have very low quantum yields for the ring-closing process, which is in contrast to switches with pyridinium and quinolinium moieties. All switches emit fluorescence in their open forms. The involved electronic transitions are traced back to an integrative picture including the DTE core and the cationic arms. The emission can be fine-tuned by the π-conjugation of the heteroaromatic cations, reaching the red spectral region for DTEs with acridinium moieties. On ring-closing of the DTEs the fluorescence is not observable anymore. Theoretical calculations point to rather low-lying energy levels of the highly conjugated ring-closed DTEs, which would originate near-infrared emission (> 1200 nm). The latter is predicted to be very weak due to the concurrent non-radiative deactivation, according to the energy-gap law. In essence, an ON-OFF fluorescence switching as the result of the electrocyclic ring-closing reaction is observed.The authors acknowledge the financial support by the Spanish Ministerio de Ciencia e Innovación (grant PID2020-119992GB-I00 for U.P., PID2019-104293GB-I00 for F.N., PID2019-108292RA-I00, EUR2020-112189 for A.J.M.-M.), the Consejería de Universidad, Investigación e Innovación/Junta de Andalucía (grant P18-FR-4080 for U.P.), the European Research and Development Fund (ERDF), and the Junta de Andalucía / University of Huelva (grant UHU-202070 for U.P.). A.J.M.-M. thanks the AEI Research State Agency for a Ramón y Cajal research contract (RYC-2017-21783). The authors are indebted to the Supercomputing and Bioinformatics Centre (SCBI) of the University of Málaga for making available the computer resources that were employed for the theoretical calculations

Atlas de las praderas marinas de España

Knowledge of the distribution and extent of seagrass habitats is currently the basis of management and conservation policies of the coastal zones in most European countries. This basic information is being requested through European directives for the establishment of monitoring programmes and the implementation of specific actions to preserve the marine environment. In addition, this information is crucial for the quantification of the ecological importance usually attributed to seagrass habitats due to, for instance, their involvement in biogeochemical cycles, marine biodiversity and quality of coastal waters or global carbon budgets. The seagrass atlas of Spain represents a huge collective effort performed by 84 authors across 30 Spanish institutions largely involved in the scientific research, management and conservation of seagrass habitats during the last three decades. They have contributed to the availability of the most precise and realistic seagrass maps for each region of the Spanish coast which have been integrated in a GIS to obtain the distribution and area of each seagrass species. Most of this information has independently originated at a regional level by regional governments, universities and public research organisations, which explain the elevated heterogeneity in criteria, scales, methods and objectives of the available information. On this basis, seagrass habitats in Spain occupy a total surface of 1,541,63 km2, 89% of which is concentrated in the Mediterranean regions; the rest is present in sheltered estuarine areas of the Atlantic peninsular regions and in the open coastal waters of the Canary Islands, which represents 50% of the Atlantic meadows. Of this surface, 71.5% corresponds to Posidonia oceanica, 19.5% to Cymodocea nodosa, 3.1% to Zostera noltii (=Nanozostera noltii), 0.3% to Zostera marina and 1.2% to Halophila decipiens. Species distribution maps are presented (including Ruppia spp.), together with maps of the main impacts and pressures that has affected or threatened their conservation status, as well as the management tools established for their protection and conservation. Despite this considerable effort, and the fact that Spain has mapped wide shelf areas, the information available is still incomplete and with weak precision in many regions, which will require an investment of major effort in the near future to complete the whole picture and respond to demands of EU directives

Atlas de las praderas marinas de España

Knowledge of the distribution and extent of seagrass habitats is currently the basis of management and conservation policies of the coastal zones in most European countries. This basic information is being requested through European directives for the establishment of monitoring programmes and the implementation of specific actions to preserve the marine environment. In addition, this information is crucial for the quantification of the ecological importance usually attributed to seagrass habitats due to, for instance, their involvement in biogeochemical cycles, marine biodiversity and quality of coastal waters or global carbon budgets. The seagrass atlas of Spain represents a huge collective effort performed by 84 authors across 30 Spanish institutions largely involved in the scientific research, management and conservation of seagrass habitats during the last three decades. They have contributed to the availability of the most precise and realistic seagrass maps for each region of the Spanish coast which have been integrated in a GIS to obtain the distribution and area of each seagrass species. Most of this information has independently originated at a regional level by regional governments, universities and public research organisations, which explain the elevated heterogeneity in criteria, scales, methods and objectives of the available information. On this basis, seagrass habitats in Spain occupy a total surface of 1,541,63 km2, 89% of which is concentrated in the Mediterranean regions; the rest is present in sheltered estuarine areas of the Atlantic peninsular regions and in the open coastal waters of the Canary Islands, which represents 50% of the Atlantic meadows. Of this surface, 71.5% corresponds to Posidonia oceanica, 19.5% to Cymodocea nodosa, 3.1% to Zostera noltii (=Nanozostera noltii), 0.3% to Zostera marina and 1.2% to Halophila decipiens. Species distribution maps are presented (including Ruppia spp.), together with maps of the main impacts and pressures that has affected or threatened their conservation status, as well as the management tools established for their protection and conservation. Despite this considerable effort, and the fact that Spain has mapped wide shelf areas, the information available is still incomplete and with weak precision in many regions, which will require an investment of major effort in the near future to complete the whole picture and respond to demands of EU directives.Versión del edito