LIVE/DEAD YEAST VIABILITY STAINING AS A TOOL FOR IMPROVING ARTISANAL PILSNER BEER PRODUCTION

The production of an artisanal beer, made by brewers using traditional practices on a small scale, is founded on the empirical adjustment of parameters, including yeasts handling and serial repitching. The aim of this study was to monitor yeast viability during different stages of artisanal beer productions through the Live/Dead Yeast viability staining and to correlate it with fermentation dynamics in order to increase process standardization and to maintain the quality of final products. Yeast viability and fermentation activities were evaluated during seven fermentation cycles of an artisanal pilsner beer. Yeast inoculated with higher viability performed generally better in fermentation, resulting in faster sugar consumption, faster ethanol production and stability. Handling yeast and serial repitching based on Live/Dead viability measurements, could be the key way to ensure reliable manufacture of high quality beer and to improve process standardization particularly for microbreweries, where variability of production can be a challenging point

Unraveling the peculiar modus operandi of a new class of solvatochromic fluorescent molecular rotors by spectroscopic and quantum mechanical methods

A prototype for a new class of fluorescent molecular rotors (FMRs), namely 4-(diphenylamino)phthalonitrile (DPAP), was synthesized and its sensitivity towards solvent polarity and viscosity probed using photophysical and computational methods. DPAP is characterized by a pronounced fluorosolvatochromism in polarity-dependent absorption, emission and fluorescent lifetime experiments. At the same time, a strong viscosity response is observed, especially in polar and protic solvents. Quantum mechanical calculations assisted in interpreting the unusual solvent sensitivity of DPAP in terms of its high flexibility, giving rise to solvent-independent, barrier-free rotations. As a matter of fact, the modus operandi in DPAP contrasts that of traditional FMRs involving twisted intramolecular charge transfer (TICT) states. The influence of this unusual flexible character on excitation and emission energies was studied using computational methods upon considering twisting of the molecule in solvents of different polarity. Furthermore, a detailed characterization of the excited state profile was attained using time resolved spectroscopy techniques. In particular, a contrasting deactivation pattern of the intramolecular charge transfer (ICT) state was observed in low and high polar media. Moreover, in low and medium polar solvents strong emission is accompanied by triplet excited state formation, while in high polar and protic solvents the ICT state is highly stabilized and decays primarily non-radiatively. Notably, a viscosity increase in the latter solvents hampers rotations leading to a strong emission enhancement. This latter behavior, coupled to a remarkable solvatochromic character, makes DPAP a promising probe for biological and environmental sensing and imaging applications

Cyclopenta[hi]aceanthrylene decorated with multiple and long alkoxy chains: physicochemical properties and single-walled carbon nanotubes exfoliation capability

A rod-like cyclopenta[hi]aceanthrylene (CPA) derivative bearing three dodecyloxy chains at each of its two terminal positions was prepared. Spectroscopic (i.e., steady-state absorption and fluorescence) and electrochemical studies carried out with this polycyclic aromatic hydrocarbon (PAH) derivative showed an intense absorption through the entire UV-vis spectral range, weak fluorescence, small HOMO-LUMO gap, and excellent electron accepting capability. Transient absorption spectroscopy (TAS) revealed the formation of singlet and triplet excited states; the latter was, however, only observed in the presence of a triplet sensitizer. The exfoliation capability of this lipophilic CPA towards single-walled carbon nanotubes (SWCNTs) in THF was also investigated. On one hand, transmission electron microscopy (TEM) pointed to an efficient debundling of SWCNTs by the CPA derivative by means of non-covalent interactions. On the other hand, important differences in the ground and excited state features of the uncomplexed and SWCNT-complexed CPA were revealed by Raman and TASFinancial support from the “Solar Energy goes Hybrid” Initiative of the Bavarian Ministry for Science, Culture and Education (SolTech), Comunidad de Madrid (FOTOCARBON), and Spanish MICINN (CTQ2017-85393-P) is acknowledge

Ultrasound-induced transformation of fluorescent organic nanoparticles from a molecular rotor into rhomboidal nanocrystals with enhanced emission

Fluorescent organic nanoparticles (FONs) based on aggregation-induced emission (AIE) are receiving increasing attention owing to their simple preparation, enhancedoptical properties, and a wide range of applications. Therefore, finding simple methods to tune the structural and emissive properties of FONs is highly desirable. In this context, we discuss the preparation of highly emissive, amorphous AIE spherical nanoparticles based on a structurally-simple molecular rotor and their sonochemicaltransformation into rhomboidal nanocrystals. Interestingly, the ultrasound-induced modification of the morphology is accompanied by a remarkable enhancement in the stability and emission of the resulting nanocrystals. Detailed characterization of both spherical and rhomboidal nanoparticles was carried out by means of several microscopic, crystallographic, and spectroscopic techniques as well as quantum mechanical calculations. In a nutshell, this work provides a unique example of the ultrasound-induced switching of morphology, stability, and emission in FONsFinancial support from Spanish Ministry of Economy and Competitivity, MICINN (CTQ-2011-24187/BQU), MIUR through FIRB program (contract no. RBFR10DAK6), ERC Advanced Grant 2012 (number 320951

Synthesis of Enantioenriched Amines by Iron-Catalysed Amination of Alcohols Employing at Least One Achiral Substrate

The synthesis of a broad range of enantioenriched amines by the direct Fe-catalysed coupling of amines with alcohols through the borrowing hydrogen strategy, while at least one of these substrates is achiral is reported. When starting from α-chiral amines and achiral alcohols, a wide range of enantioenriched amine products, including N-heterocyclic moieties can be obtained with complete retention of stereochemistry and the power of this method is demonstrated in the one-step synthesis of known pharmaceuticals from commercially available, simple enantiopure primary amines and achiral alcohols. It was also found that the use of β-branched enantioenriched primary alcohols and achiral amines as reaction partners leads to a partial loss of stereochemical integrity in the final product, however, a systematic optimization enabled partial retention of enantiopurity and possible parameters effecting for racemization were identified.</p

Highly enantioselective imine hydrogenation catalyzed by ruthenium phosphane-phosphite diamine complexes

Mildly does it: A highly enantioselective catalyst for the hydrogenation of N-aryl imines is described (see scheme). This catalyst offers practical advantages because it operates under very mild conditions and is based on an Ru complex with a diamine as the sole chiral ligand.Ministerio de Economía y Competitividad CTQ2009-11867, CSD2007-00006European Union PITN 2008-215193Junta de Andalucía 2008/FQM-383

Magnetic Interplay between π-Electrons of Open-Shell Porphyrins and d-Electrons of Their Central Transition Metal Ions.

Magnetism is typically associated with d- or f-block elements, but can also appear in organic molecules with unpaired π-electrons. This has considerably boosted the interest in such organic materials with large potential for spintronics and quantum applications. While several materials showing either d/f or π-electron magnetism have been synthesized, the combination of both features within the same structure has only scarcely been reported. Open-shell porphyrins (Pors) incorporating d-block transition metal ions represent an ideal platform for the realization of such architectures. Herein, the preparation of a series of open-shell, π-extended Pors that contain magnetically active metal ions (i.e., CuII , CoII , and FeII ) through a combination of in-solution and on-surface synthesis is reported. A detailed study of the magnetic interplay between π- and d-electrons in these metalloPors has been performed by scanning probe methods and density functional theory calculations. For the Cu and FePors, ferromagnetically coupled π-electrons are determined to be delocalized over the Por edges. For the CoPor, the authors find a Kondo resonance resulting from the singly occupied CoII dz 2 orbital to dominate the magnetic fingerprint. The Fe derivative exhibits the highest magnetization of 3.67 μB (S≈2) and an exchange coupling of 16 meV between the π-electrons and the Fe d-states

Ultrastrong exciton−photon coupling in broadband solar absorbers

The recent development of organic polaritonic solar cells, in which sunlight absorbers and photon modes of a resonator are hybridized as a result of their strong coupling, has revealed the potential this interaction offers to control and enhance the performance of these devices. In this approach, the photovoltaic cell is built in such a way that it also behaves as an optical cavity supporting spectrally well-defined resonances, which match the broad absorption bands of the dyes employed. Herein we focus on the experimental and theoretical analysis of the specific spectral and angular optical absorption characteristics of a broadband light harvester, namely a subphthalocyanine, when operating in the ultrastrong coupling regime. We discuss the implications of having a broad distribution of oscillator strengths and demonstrate that rational design of the layered structure is needed to optimize both the spectral and the angular response of the sunlight harvester dyeFunding for this work was provided by the Spanish “Ministerio de Ciencia, Innovación y Universidades (MCIU)” through AEI/FEDER(UE) projects PID2020-116593RB-I00 and PID2020-116490GBI00 as well as through projects EXPLORA FIS2017-91018-EXP, PCI2018-093145 (QuantERA program, EC), CEX2018-000805-M (María de Maeztu Programme for Units of Excellence in R&D), SEV2016-0686 (Severo Ochoa Programme for Centres of Excellence in R&D), and MODEFotovoltaica (Materiales Orgánicos Disruptivos para Energía Fotovoltaica) (RED2018-102815-T). V.E. thanks La Caixa Foundation (ID 100010434) for funding of her PhD (fellowship LCF/BQ/ES15/10360025). L.C. thanks Junta de Andalucía and the European Regional Development Funds program (EU-FEDER) for financial support (DOC_00220). This work was partially funded also by the European Research Council through Grant ERC-2016-StG-71487

Magnetic interplay between π-electrons of open-shell porphyrins and d-electrons of their central transition metal ions

Magnetism is typically associated with d- or f-block elements, but can also appear in organic molecules with unpaired π-electrons. This has considerably boosted the interest in such organic materials with large potential for spintronics and quantum applications. While several materials showing either d/f or π-electron magnetism have been synthesized, the combination of both features within the same structure has only scarcely been reported. Open-shell porphyrins (Pors) incorporating d-block transition metal ions represent an ideal platform for the realization of such architectures. Herein, the preparation of a series of open-shell, π-extended Pors that contain magnetically active metal ions (i.e., CuII, CoII, and FeII) through a combination of in-solution and on-surface synthesis is reported. A detailed study of the magnetic interplay between π- and d-electrons in these metalloPors has been performed by scanning probe methods and density functional theory calculations. For the Cu and FePors, ferromagnetically coupled π-electrons are determined to be delocalized over the Por edges. For the CoPor, the authors find a Kondo resonance resulting from the singly occupied CoII dz2 orbital to dominate the magnetic fingerprint. The Fe derivative exhibits the highest magnetization of 3.67 μB (S≈2) and an exchange coupling of 16 meV between the π-electrons and the Fe d-state