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

A fluorescent acrylamide-type monomer bearing an environment-sensitive methoxybenzocoumarin structure for the development of functional polymeric sensors

A new fluorescent acrylamide-type monomer bearing a hydrogen bonding- and polarity-sensitive benzocoumarin fluorophore was synthesized. The absorption spectra, fluorescence spectra, and fluorescence lifetime of a model compound were measured in ten solvents with different hydrogen-bonding abilities and polarities to investigate the sensitivity of the fluorophore to the surrounding environment. These spectroscopic studies demonstrated that the fluorophore emits stronger fluorescence in more protic, polar environments. A fluorescent polymeric thermometer was prepared from N-isopropylacrylamide and the new fluorescent monomer, and it showed good functionality in aqueous solution (e.g., high sensitivity to temperature changes and high chemical stability), indicating the applicability of the herein developed fluorescent monomer for use in functional sensors.We acknowledge the Japan Science and Technology Agency (the Development of Advanced Measurement and Analysis Systems program for S. U.), the Japan Society for the Promotion of Science (Grant-in-Aid for Challenging Exploratory Research 16K14002 for S. U.), and the Spanish Ministry for Economy and Competitiveness (grants CTQ2008-06777-C02-02 and CTQ2014-54729-C2-1-P for U. P. and PhD fellowship BES-2009-012264 and travel grant EEBB-I-13-07155 for P. R.).Departamento de Química "Profesor José Carlos Vílchez Martín

Molecular Implementation of Sequential and Reversible Logic Through Photochromic Energy Transfer Switching

Photochromic spiropyrans modified with fluorophores were investigated as molecular platforms for the achievement of fluorescence switching through modulation of energy transfer. The dyads were designed in such a way that energy transfer is only observed for the open forms of the photochrome (merocyanine and protonated merocyanine), whereas the closed spiropyran is inactive as an energy acceptor. This was made possible through a deliberate choice of fluorophores (4-amino-1,8-naphthalimide, dansyl, and perylene) that produce zero spectral overlap with the spiro form and considerable overlap for the merocyanine forms. From the Förster theory, energy transfer is predicted to be highly efficient and in some cases of 100 % efficiency. The combined switching by photonic (light of λ>530 nm) and chemical (base) inputs enabled the creation of a sequential logic device, which is the basic element of a keypad lock. Furthermore, in combination with an anthracene-based acidochromic fluorescence switch, a reversible logic device was designed. This enables the unambiguous coding of different input combinations through multicolour fluorescence signalling. All devices can be conveniently reset to their initial states and repeatedly cycled

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

a mimic for essential features of the vision process

Publisher Copyright: © 2023 The Royal Society of Chemistry. This work was supported by the Spanish Ministerio de Ciencia e Innovación (grant PID2020-119992GB-I00 for U.P.), the Consejería de Economía, Conocimiento, Empresas y Universidad/Junta de Andalucía (grant P18-FR-4080 for U.P.), the Portuguese Fundação para a Ciência e a Tecnologia – FCT/MCTES (grant CEECIND/00466/2017 for N.B.), and by LAQV-REQUIMTE (through UIDB/50006/2020 and UIDP/50006/2020).The tailored design of a light-triggered supramolecular cascade results in an artificial machinery that assimilates the transduction of photons into chemical communication and the final release of a neurotransmitter. This is reminiscent of key steps in the natural vision process.preprintpublishe

Toward Light-Controlled Supramolecular Peptide Dimerization

The selective photodeprotection of the NVoc-modified FGG tripeptide yields the transformation of its 1:1 receptor−ligand complex with cucurbit[8]uril into a homoternary FGG2@CB8 assembly. The resulting lightinduced dimerization of the model peptide provides a tool for the implementation of stimuli-responsive supramolecular chemistry in biologically relevant contexts.The work was supported by the Associate Laboratory for Green ChemistryLAQV (UIDB/50006/2020) and by the Applied Molecular Biosciences UnitUCIBIO (UIDB/ 04378/2020), both financed by FCT. FCT/MCTES is also acknowledged for supporting the National Portuguese NMR Network (ROTEIRO/0031/2013-PINFRA/22161/2016, cofinanced by FEDER through COMPETE 2020, POCI, PORL, and FCT through PIDDAC) and for the grants PTDC/QUICOL/32351/2017, PTDC/QUI-QFI/30951/2017, and CEECIND/00466/2017 (N.B.). U.P. thanks the Spanish Ministry of Science, Innovation, and Universities (CTQ2017-89832-P). We are grateful to Dr. J.P. Da Silva for the mass spectrometry data (equipment financed by CRESC Algarve 2020 and COMPETE 2020; project EMBRC.PT ALG-01-0145-FEDER022121). Funding for open access charge: Universidad de Huelva / CBU

Aportación al conocimiento de los cecidios encontrados en la vegetación de Murcia y localidades próximas del SE de España (Arthropoda: Insecta y Acari; Bacterii)

54 especies cecidógenas de las familias Eriophyidae (Acari), Ceci - domyiidae y Tephritidae, (Diptera), Aphididae, Coccidae, Psyllidae y Tingidae (Hemiptera), Cynipidae y Tenthredinidae (Hymenop - tera), Gelechiidae (Lepidoptera) y Rhizobiales (Proteobacteria) se registran en la Región de Murcia. 34 se citan por primera vez en Murcia. Se ilustran y definen con caracteres diagnósticos todas las agallas. En la familia Fagaceae se ha detectado el mayor número de especies cecidícolas, con 12 especies en el género Quercus , seguida de Asteraceae con 7 especies en 6 especies vegetales y Salicaceae con 6 especies en 4 hospedantes. Se proporciona una tabla con las especies inductoras de agallas y los hospedantes atacados. Finalmente, se menciona la presencia de la fasciación sobre Pinus halepensis

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

Engineering the BASHY Dye Platform toward Architectures with Responsive Fluorescence

A set of nine boronic-acid-derived salicylidenehydrazone (BASHY) complexes has been synthesized in good to very good chemical yields in a versatile three-component reaction. In an extension to previous reports on this dye platform, the focus was put on the electronic modification of the “vertical” positions of the salicylidenehydrazone backbone. This enabled the observation of fluorescence quenching by photoinduced electron transfer (PeT), which can be reverted by the addition of acid in organic solvent (OFF-ON fluorescence switching). The resulting emission is observed in the green-to-orange spectral region (maxima at 520–590 nm). In contrast, under physiological pH conditions in water, the PeT process is inherently decativated, thereby enabling the observation of fluorescence in the red-to-NIR region (maxima at 650–680 nm) with appreciable quantum yields and lifetimes. The latter characteristic supported the application of the dyes in fluorescence lifetime imaging (FLIM) of live A549 cells.This work was generously supported by the Portuguese FundaçãoparaaCiênciaeTecnologia [grantsPTDC/QUI-OUT/ 3989/2021 (P.G.); institutional grants UIDB/04138/2020 and UIDP/04138/2020 (iMed)], theSpanishMinisteriodeCienciae Innovación [grants CTQ2017-89832-P, PID2020-119992GB-I00 (bothtoU.P.),andPID2019-104293GB-I00(F.N.)], theConsejería deUniversidad, Investigacióne Innovación/JuntadeAndalucía [grantP18-FR-4080(U.P.)],andtheUniversidaddeHuelva/Junta deAndalucía [UHU202070 (U.P.)]. TheNMRspectrometersare partofthePortugueseNationalNMRNetwork(PTNMR)andare partially supportedby Infrastructure Project No. 022161 (cofinancedbyFEDER throughCOMPETE2020, POCI, PORL, and FCTthroughPIDDAC).WealsoacknowledgetheSupercomputingandBioinformaticsCentre(SCBI)oftheUniversityofMálaga forprovidingthecomputer resourcesusedfor thetheoretical calculations.Departamento de Química "Profesor José Carlos Vílchez Martín

OFF-ON-OFF Fluorescence Switch with T-Latch Function

A novel molecular system with characteristics of an OFF-ON-OFF fluorescence switch was designed to integrate the function of a T-latch. In detail, a receptor(1)-fluorophore-receptor(2) architecture was adopted to achieve fluorescence switching upon addition of protons