From light-induced processes in solution toward solid/liquid and liquid/liquid interfaces: the use of peri-xanthenoxanthene derivatives as photoactive compounds

The efficient exploitation of solar energy for chemical bond formation in homogeneous solutions is often hampered by the fast rate of charge recombination within the solvent cage. Heterogeneous biphasic systems can segregate the charge carriers in different chemical environments, allowing the charge transfer to occur only across the interface between the phases. In this way, increased charge separation yield and catalyst recyclability can be obtained. Nevertheless, the use of chemical interfaces to foster photoinduced transformations has not been extensively explored. Aiming to explore the advantages that biphasic systems can provide compared to homogeneous solutions, this work focuses on using derivatives of peri-xanthenoxanthene (PXX), an oxygen-doped analogue of anthanthrene already employed in homogeneous photocatalysis, for photoinduced processes in heterogeneous systems. In particular, the interface between solid/liquid and liquid/liquid immiscible solutions have been investigated. In chapter 2, spectroscopic, electrochemical and computational analyses on PXX derivatives are presented. Specifically, the effect of the elongation of the aromatic surface and the replacement of the oxygen with sulphur atoms was investigated. In chapter 3, novel PXX derivatives were loaded on polymeric surfaces and the functionalised materials employed in the photodebromination of p-bromoacetophenone, both dispersed in bulk solution and within a microfluidic reactor. Aiming to develop a biphasic liquid system to foster photoinduced electron transfer (PET) between a fluorinated and organic liquid phase, in chapter 4 the attempts to obtain selective orthogonal solubility of the electron donors and acceptors by functionalisation with alkylic or fluorinated pendants are reported. This project was the first to extensively investigate the use of PXX derivatives in heterogeneous photoreactions and characterise the photophysical properties of the functionalised materials. The studies revealed a rich band gap tunability of up to 1.3 eV for PXX derivatives in solution. In addition, the loading on polymeric scaffolds not only improved the reaction yield but product conversion up to 30% after three cycles of catalyst recycling was obtained. Consequently, biphasic systems can be considered a promising way to foster the applicability of organic photocatalysis in industrial processes

Solvent-driven chirality for luminescent self- assembled structures: experiments and theory

We describe, for a single platinum complex bearing a dipeptide moiety, a solvent-driven interconversion from twisted to straight micrometric assembled structures with different chirality. The photophysical and morphological properties of the aggregates have been investigated as well as the role of the media and concentration. A real-time visualization of the solvent-driven interconversion processes has been achieved by confocal microscopy. Finally, atomistic and coarse-grained simulations, providing results consistent with the experimental observations, allow to obtain a molecular-level insight into the interesting solvent-responsive behavior of this system

Future area expansion outweighs increasing drought risk for soybean in Europe

The European Union is highly dependent on soybean imports from overseas to meet its protein demands. Individual Member States have been quick to declare self-sufficiency targets for plant-based proteins, but detailed strategies are still lacking. Rising global temperatures have painted an image of a bright future for soybean production in Europe, but emerging climatic risks such as drought have so far not been included in any of those outlooks. Here, we present simulations of future soybean production and the most prominent risk factors across Europe using an ensemble of climate and soybean growth models. Projections suggest a substantial increase in potential soybean production area and productivity in Central Europe, while southern European production would become increasingly dependent on supplementary irrigation. Average productivity would rise by 8.3% (RCP 4.5) to 8.7% (RCP 8.5) as a result of improved growing conditions (plant physiology benefiting from rising temperature and CO2 levels) and farmers adapting to them by using cultivars with longer phenological cycles. Suitable production area would rise by 31.4% (RCP 4.5) to 37.7% (RCP 8.5) by the mid-century, contributing considerably more than productivity increase to the production potential for closing the protein gap in Europe. While wet conditions at harvest and incidental cold spells are the current key challenges for extending soybean production, the models and climate data analysis anticipate that drought and heat will become the dominant limitations in the future. Breeding for heat-tolerant and water-efficient genotypes is needed to further improve soybean adaptation to changing climatic conditions

Boron-nitrogen-doped nanographenes: a synthetic tale from borazine precursors

In this paper we report a comprehensive account of our synthetic efforts to prepare borazino-doped hexabenzocoronenes using the Friedel-Crafts-type electrophilic aromatic substitution. We showed that hexafluoro-functionalized aryl-borazines, bearing an ortho fluoride leaving group on each N- and B-aryl rings, could lead to cascade-type electrophilic aromatic substitution events in the stepwise C-C bond formation giving higher yields of borazinocoronenes than those obtained with borazine precursors bearing fluoride leaving groups at the ortho positions of the B-aryl substituents. It is with this pathway that an unprecedented boroxadizine-doped PAH featuring a gulf-type periphery could be isolated, and its structure proved through single crystal X-ray diffraction analysis. Mechanistic studies on the stepwise Friedel-Crafts-type cyclisation suggest that the mechanism of the planarization reaction proceeds through extension of the π system. To appraise the doping effect of the boroxadizine unit on the optoelectronic properties of topology-equivalent molecular graphenes, the all-carbon and pyrylium PAH analogues, all featuring a gulf-type periphery, were also prepared. As already shown for the borazino-doped hexabenzocoronene, the replacement of the central benzene ring by its B3N2O congener widens the HOMO-LUMO gap and it dramatically enhances the fluorescence quantum yield

Photoreduction of anthracenes catalyzed by peri ‐xanthenoxanthene: a scalable and sustainable Birch‐type alternative

The typical Birch reduction transforms arenes into cyclohexa‐1,4‐dienes by using alkali metals, an alcohol as a proton source, and an amine as solvent. Capitalizing on the strong photoreductive properties of peri‐xanthenoxanthene (PXX), herein we report the photocatalyzed “Birch‐type” reduction of acenes by employing visible blue light irradiation at room temperature in the presence of air. Upon excitation at 405 or 460 nm in the presence of a mixture of N, N‐diisopropylethylamine (DIPEA) and trifluoromethanesulfonimide (HNTf2) in DMSO, PXX photocatalyzes the selective reduction of full‐carbon acene derivatives (24–75 %). Immobilization of PXX onto polydimethylsiloxane (PDMS) beads (PXX‐PDMS) allowed the use of the catalyst in heterogeneous batch reactions, giving 9‐phenyl‐9,10‐dihydroanthracene in high yield (68 %). The catalyst could easily be recovered and reused, with no notable drop in performance observed after five reaction cycles. Integration of the PXX‐PDMS beads into a microreactor enabled the reduction of acenes under continuous‐flow conditions, thereby validating the sustainability and scalability of this heterogeneous‐phase approach

Gli autori della letteratura italiana sul grande e piccolo schermo. Modified-used datasets and resulting tables

The datasets contains information about cinema and television products in whose creation Italian writers are involved. Data have been collected relying on Wikidata and IMDb and refer to the contributions of Italian writers whose Wikidata value for the property "country of citizenship" corresponds either with "Kingdom of Italy" or "Italy" (also both can occur), while their "occupation" is "poet" or "novelist". Each dataset has a specific focus and groups data related to a specific topic or category

Valutazione della biodiversita delle razze autoctone toscane: punti critici e strategie risolutive

La tutela delle razze locali e della cultura rurale ad esse legata, è un obiettivo intensamente perseguito dalla fine del secolo scorso. Oggi alla tutela delle risorse genetiche locali, ma più in generale dell’a- grobiodiversità, si legano indissolubilmente i temi della sostenibilità ambientale, dell’economia circolare, della tutela del suolo, dell’acqua, del clima e della biodiversità naturale e selvatica. Ciascuno di questi temi necessita di strumenti di tutela e di gestione specifici, per poter fare scelte sempre più efficaci in tutti gli ambiti di politica e gestione territoriale. Lo scopo è quello di contrastare l’abbandono di razze animali a rischio di estinzione, cercando di recuperare e sviluppare il know-how in materia di selezione, riproduzione e altre pratiche agronomiche tradizionali, indirizzate verso opportunità economiche moderne e innovative che sfruttino le stesse conoscenze e pratiche tradizionali. La conservazione e la valorizzazione delle risorse genetiche locali, soprattutto a rischio di estinzio- ne, devono essere sorrette da un’attività scientifica sistematica diretta, oltre che alla caratterizzazione e conservazione, anche all’individuazione delle loro caratteristiche in particolari condizioni climatiche, agronomiche o per particolari impieghi e all’individuazione dell’insieme di buone pratiche e di esperienze pilota capaci di migliorare i processi di valorizzazione. Per far questo occorre che l’obbiettivo principale della valorizzazione dei prodotti agroalimentari locali debba essere quello di aumentare la loro redditività creando maggior interesse negli agricoltori verso le razze e varietà locali. L’azione di valorizzazione deve essere accompagnata da una maggiore informazione nei confronti dei consumatori, sempre più attenti alla qualità dei prodotti e sempre più interessati alle produzioni locali. Fondamentale diventa impostare un ragionamento di policy che parta dai territori e dalle comunità locali. Incentivare la nascita di strategie territoriali per la tutela della biodiversità agricola e alimentare di un territorio a partire dal recupero, conservazione e valorizzazione delle razze e delle varietà locali a rischio di estinzione, è un modo strettamente connesso alla tutela dell’agricoltura come attività economica a presidio del territorio e della cultura locale. Inoltre, in vista della nuova programmazione dello sviluppo rurale, fondamentale risulta incentivare l’attivazione di progetti integrati (di filiera, territoriali, di distretto, ecc.) sui temi legati alla tutela e valorizzazione dell’agrobiodiversità regionale, vista la positiva esperienza dell’uso di questo strumento nelle precedenti programmazioni. Il presente lavoro si prefigge di individuare evidenzia alcune aree di miglioramento del sistema regionale toscano attuale, LR 64/04, utili ad affrontare l’attuazione del sistema nazionale della Legge 194/2015; inoltre evidenzia le principali necessità di sostegno con possibili indicazioni di policy. Per raggiungere questi obiettivi, sono stati sviluppati tre filoni di ricerca. In primo luogo, è stata fatta una valutazione delle consistenze delle razze autoctone toscane negli ultimi 10 anni. L’indagine è stata svolta grazie alla stretta collaborazione con l’Associazione Italiana Allevatori (AIA) e le varia associazioni di razza. L’obiettivo era quello di individuare come si sono evolute queste razze nel tempo, alla luce di scelte manageriali e politiche adottate. Successivamente sono stati individuati tre casi studio (Razza Garfagnina Bianca, Razza Massese e Razza Mucco Pisano) su cui sono state fate indagini mirate in azienda. Nello specifico, sono stati condotti questionari in azienda, per indagare sull’opinione degli allevatori in merito alla nuova legge 194/2015 e le possibili policy da adottare per migliorare la situazione relativa alle razze in via di estinzione. Infine, è stata scelta una razza (Cavallo Bardigiano), sulla quale è stato condotto uno studio sull’attività di selezione genetica, valutando i principali parametri di miglioramento genetico (ereditabilità, correlazioni ecc.

Gli autori della letteratura italiana contemporanea sul grande e piccolo schermo. Un’analisi quantitativa

Italian literature entertains a long-standing relation with cinema and television. While several analyses have investigated details of singular phenomena, a broader quantitative analysis of the context and the dynamics characterizing such relation is missing. In this article we present an open dataset created from Wikidata and IMDb, and we present an exploratory data analysis to answer questions about TV and movie productions, writers’ contributions to screenplay, and gender balance.La letteratura e i letterati italiani intrattengono rapporti di diversa natura con il mondo del cinema e della televisione. Numerose analisi qualitative hanno indagato le dinamiche e i frutti di queste relazioni, mentre un'analisi quantitativa che permetta di evidenziare le caratteristiche generali del contesto in cui queste si inseriscono è assente nella letteratura scientifica. In questo contributo presentiamo un dataset creato a partire da Wikidata e IMDb per rispondere a tali domande usando metodi quantitativi. Viene presentata un’analisi preliminare sulle produzioni cinematografiche, il contributo degli scrittori nella transcodifica, e i rapporti di genere