Actualización del currículum en educación química: la importancia de la luz solar en nuestra vida

Els processos induïts per la llum solar són vitals per als éssers vius. La naturalesa ens demostra que els processos tèrmics i fotoquímics es complementen per donar lloc a molècules valuoses per als éssers vius. A més, hi ha una gran varietat d'aplicacions tecnològiques basades en la capacitat d'alguns materials per absorbir la llum. La llum solar és, sense cap mena de dubte, el reactiu químic més «verd». Però també cal tenir en compte que la sobreexposició solar pot provocar efectes adversos en organismes i materials.Sunlight induced processes are essential for living organisms. Nature shows that thermal and photochemical processes are combined to provide vital molecules in living beings. Furthermore, there are a variety of technological applications based on the capacity of some materials to absorb light. Sunlight is, without doubt, the «greenest» chemical reagent. But we must also bear in mind that sun exposure can cause adverse effects in organisms and materials.Los procesos inducidos por la luz solar son vitales para los seres vivos. La naturaleza nos demuestra que los procesos térmicos y fotoquímicos se complementan para dar lugar a moléculas valiosas para los seres vivos. Además, existe una gran variedad de aplicaciones tecnológicas basadas en la capacidad de algunos materiales para absorber la luz. La luz solar es, sin lugar a dudas, el reactivo químico más «verde». Sin embargo, hay que tener en cuenta que la sobreexposición solar puede provocar efectos adversos en organismos y materiales

Diels-Alder reaction between indoles and cyclohexadienes photocatalyzed by a (thia)pyrylium salt

"Thiapyrylium salt 1 is an efficient photocatalyst in the Diels-Alder reaction between indoles (InHs) and 1,3-cyclohexadienes (CHDs). For instance, irradiation of deaerated dichloromethane solutions containing 1 (1 mM), indole (20 mM) and cyclohexadiene (40 mM), in the presence of an acylating agent, led to the Diels-Alder cycloadduct in 62% yield (endo:exo ratio of 1.8:1). Taking into account the very high intersystem crossing yield (Φisc = 0.97) of thiapyrylium salt 1, involvement of its triplet excited state in this Diels-Alder reaction has been studied using steadystate and time-resolved experiments; the results are compared with those previously obtained for pyrylium salts, which exhibit a considerable fluorescence quantum yield and are assumed to operate via electron transfer from the InH to their singlet excited state."Gonzalez Bejar, Maria, [email protected] ; Stiriba, Salah Eddine, [email protected] ; Perez Prieto, Julia, [email protected]

Analysis of touristification processes in historic town centers: the city of Seville

Encouraged by the administration, the gen9otrification process has been useful in economic terms for the reactivation of the socio-cultural fabrics of historic urban spaces in decline. What was initially considered an advantage has led to the touristification of historic centers, and in turn to the alteration of their original use. In these settings, the demographic void caused by increasingly shunning local identity has combined with pressure from excessive tourism and the obsolescence of heritage protection bodies in charge of conservation. Given the crisis affecting the definitions of the current system, this study aims to review the environmental agents of heritage value in relation to the processes of touristification and gentrification. Data obtained from different methodologies are analyzed using a multidisciplinary database, a model which enables the analysis of the relevant information from the different interacting fields. This case study focuses on the historic town center of Seville, specifically between 2015 and 2020. Elements are defined as indicators for these processes and the analysis of this case study will comprise the main results of this research

Enantiocontrol in the intermolecular cyclopropanation reaction catalyzed by dirhodium(II) complexes with ortho-metalated aryl phosphine ligands

(P) and (M) dirhodium(II) complexes with ortho-metalated aryl phosphines are assessed as chiral catalysts in the enantioselective cyclopropanation of styrenes by ethyl diazoacetate; enantioselectivities up to 91% and up to 87%, respectively, for cis- and trans-2-arylcyclopropanecarboxylates are observed.Barberis, Mario, [email protected] ; Lahuerta Peña, Pascual, [email protected] ; Perez Prieto, Julia, [email protected] ; Sanau Torrecilla, Mercedes, [email protected]

Mechanistic studies on the photogeneration of o- and p-xylylenes from α,α'-dichloroxylenes

Two-colour two-laser techniques have unambiguously proved that photolysis of the o-/p-(chloromethyl)benzyl radical leads to the sequential two-photon generation of o-/pxylylene from α,α'-dichloro-o-/p-xylene.Perez Prieto, Julia, [email protected]

Triplet exciplexes as energy transfer photosensitisers

Experimental evidence is provided for the occurrence of triplet–triplet energy transfer from benzoylthiophene–indole exciplexes to naphthalenes with a remarkable stereodifferentiation; chiral recognition is also observed in the decay of the generated naphthalene triplets.Perez Prieto, Julia, [email protected] ; Galian, Raquel Eugenia, [email protected] ; Morant Miñana, Maria Carmen, [email protected]

Enhanced catalytic electrochemical reduction of dissolved oxygen with ultraclean cucurbituril[7]-capped gold nanoparticles

Gold nanoparticles capped with cucurbituril[7] have been prepared in the absence of metallic cations and organic ligands. Remarkably, these nanohybrids encapsulate dissolved oxygen and are highly active in electrochemical reduction. The effect of the presence of sodium and ammonium salts on this catalysed process is also analysed

Stereodifferentiation in the formation and decay of the encounter complex in bimolecular electron transfer with photoactivated acceptors

Experimental evidence has been obtained for the involvement of encounter complexes between both enantiomers of a π,π* triplet excited ketone and a chiral phenol or indole. Determination of the pre-equilibrium constants (KEC) and the intrinsic decay rate constants (kd) indicates a significant stereodifferentiation in both steps of the quenching process.Perez Prieto, Julia, [email protected] ; Galian, Raquel Eugenia, [email protected] ; Morant Miñana, Maria Carmen, [email protected]

La práctica especulativa como modelo pedagógico para la arquitectura

Introducción: uno de los mayores desafíos de la arquitectura como disciplina después de la crisis, ha sido repensar en cómo tendría que enfocarse la formación de los (futuros) arquitectos. En un momento en el que parece que la práctica arquitectónica -cada vez más supeditada a los humores de los mercados-, haya quedado en segundo plano, un (re)encuentro con la teoría puede ser el camino para reconfigurar su cometido en los próximos años. Objetivos: el objetivo principal será describir la práctica especulativa como modelo pedagógico para la arquitectura. Gracias a ello, se quieren alcanzar dos objetivos específicos: por un lado, proporcionar claves de entendimiento para superar el antagonismo entre teoría y práctica; y por el otro, plantear su potencial para problemas sociales y políticos a gran escala. Método: el estudio se llevará a cabo a través de la comparación de pedagogías que utilizan actualmente la práctica especulativa en la arquitectura y en el diseño, y en interacción con otras prácticas culturales. Conclusiones: una vez que se consiga alejar la disciplina arquitectónica de los aspectos comerciales o de las demandas del mercado, resituándola en un contexto más amplio y global. La práctica especulativa, en este sentido, es lo que permite enfocar estrategias para futuros posibles, y repensar, a la vez, el presente en el que vivimos

Regio- and stereo-selectivity in the intramolecular quenching of the excited benzoylthiophene chromophore by tryptophan

Laser flash photolysis studies on the photobehaviour of a series of bichromophoric derivatives bearing benzoylthiophene and tryptophan groups have shown that the efficiency of the intramolecular quenching process depends on both the stereochemistry of the chiral centers and the relative ketone versus tryptophan orientation.Perez Prieto, Julia, [email protected]