20 research outputs found

    Ion Mobility Mass Spectrometry Uncovers Guest-Induced Distortions in a Supramolecular Organometallic Metallosquare

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    The encapsulation of the tetracationic palladiummetallosquare with four pyrene-bis-imidazolylidene ligands[1]4+with aseries of organic molecules was studied byElectrosprayionization Travelling Wave Ion-Mobility MassSpectrometry (ESI TWIM-MS). The method allowed todetermine the Collision Cross Sections (CCSs), whichwereused to assess the sizechanges experienced by the host uponencapsulation of the guest molecules.When fullerenes wereused as guests,the host is expanded DCCS 13 2and 23 2,forC60or C70,respectively.The metallorectangle [1]4+was alsoused for the encapsulation of aseries of polycyclic aromatichydrocarbons (PAHs) and naphthalenetetracarboxylic diimide(NTCDI), to form complexes of formula [(NTCDI)2-(PAH)@1]4+.For these host:guest adducts,the ESI IM-MSstudies revealed that [1]4+is expanded by 47–49 2.. Theenergy-minimized structures of [1]4+,[C60@1]4+,[C70@1]4+,[(NTCDI)2(corannulene)@1]4+in the gas phase were obtainedby DFT calculations.IntroductionFunding for open access charge: CRUE-Universitat Jaume

    A Sustainable Approach to Selective Hydrogenation of Unsaturated Esters and Aldehydes with Ruthenium Catalysts

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    The reduction of esters and aldehydes to alcohols is an important reaction in the chemical industry to produce a wide range of bulk and fine chemicals. Herein, the unexpected behavior of three state-of-the-art, commercially available Ru-catalysts for the hydrogenation of these feedstocks is reported. For ester and aldehydes containing a C=C bond, it was possible to carry out the selective hydrogenation of the ester or aldehyde functionality while keeping the C=C double-bond essentially untouched. Furthermore, it is demonstrated that these substrates can be reduced under very mild reaction conditions (as low as 40 °C and 5 bar of H2) and that anisole, a solvent with a high sustainability rank, is suitable for these catalytic hydrogenations

    Implantació i Millora de l'European Project Semester (EPS) a l'EPSEVG

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    L'EPSEVG de la UPC va implantar l’European Project Semester (EPS) un programa formatiu innovador que respon a les demandes plantejades per la societat i l’Espai Europeu d’Ensenyament Superior (EEES) durant el curs 2007‐2008. L’EPS permet cobrir la demanda d’estudiants estrangers que volen venir a estudiar a l’escola, demanda, que, a nivell de grau en enginyeria no esta coberta en cap universitat catalana.L’EPS també és una oportunitat per augmentar el compromís de l’EPSEVG vers la sostenibilitat. El programa s’ha ambientalitzat d’acord amb les directrius del Pla UPC Sostenible 2015 essent la sostenibilitat un dels eixos transversals que li dona contingut i que identifica a tots els projectes desenvolupats. A més de la sostenibilitat, el programa inclou altres matèries transversals (com ara, la innovació, la gestió de projectes, l’accessibilitat...). L’EPS utilitza el model d’aprenentatge basat en projectes (Project Based Learning), i hi introdueix dos components nous: la docència en anglès i la interculturalitat dins de l’aula. Les noves tecnologies s’utilitzen tant per dinamitzar el treball dels grups com per facilitar el seu aprenentatge, doncs l’EPS inclou tallers i seminaris en la modalitat semipresencial.Peer Reviewe

    Total absorption gamma-ray spectroscopy study of the β-decay of 186Hg

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    7 pags., 9 figs., 1 tab.The Gamow-Teller strength distribution of the decay of Hg into Au has been determined for the first time using the total absorption gamma spectroscopy technique and has been compared with theoretical QRPA calculations using the SLy4 Skyrme force. The measured Gamow-Teller strength distribution and the half-life are described by mixing oblate and prolate configurations independently in the parent and daughter nuclei. In this theoretical framework the best description of the experimental beta strength is obtained with dominantly prolate components for both parent Hg and daughter Au. The approach also allowed us to determine an upper limit of the oblate component in the parent state. The complexity of the analysis required the development of a new approach in the analysis of the X-ray gated total absorption spectrum.This work was supported by Spanish Ministerio de Economía y Competitividad under grants FPA2011-24553, FPA2014-52823-C2-1-P, FPA2017-83946-C2-1-P, FPA2017-87568-P, Ministerio de Ciencia e Innovación grants PID2019-104714GB-C21 and RTI2018-098868-B-100, program Severo Ochoa (SEV-2014-0398), ENSAR (grant 262010) and by the European Union Horizon 2020 research and innovation programme under Grant Agreement No. 654002. S.E.A.O. thanks the support of CPAN Consolider-Ingenio 2010 Programme CSD2007-00042 grant. E.G. acknowledges support from TÜBITAK 2219 Abroad Research Fellowship Programme. R.B.C. acknowledges support by the Max-Planck-Partner group. Support from the technical staff and engineers of ISOLDE-CERN is acknowl- edged. W.G. acknowledges the support of STFC (UK) council grant ST/P005314/1. V.G. acknowledges the support of the National Science Center, Poland, under Contract No. 2019/35/D/ST2/02081. This work was also supported by the National Research, Development and Innovation Fund of Hungary, financed under the K18 funding scheme with Projects No. K 128729 and NN128072. P.S. acknowledges support from MCI/AEI/FEDER, UE (Spain) under grant PGC2018-093636-B-I0

    Nickel and palladium supramolecular organometallic complexes based on NHC-ligands with polyaromatic moieties for host-guest chemistry studies

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    Compendi d'articlesSe ha obtenido una nueva familia de cuatro Complejos Organometálicos Supramoleculares (SOCs) basados en pireno. Dentro de los cuales se ha desarrollado un nuevo receptor de PAH, capaz de discernir entre los diferentes PAH en función de su forma, tamaño, y número de electrones-pi. Hemos desarrollado una estrategia eficiente para la extracción de PAH, que son compuestos tóxicos y carcinogénicos, en disolventes orgánicos. Paralelamente, se han obtenido dos receptores de fulereno, capaces de adaptar su tamaño a la forma del fulereno. Debido a la mayor afinidad respecto a un fulereno específico, mostramos un potencial nuevo método de purificación de fulerenos. Describimos el primer sistema host-guest utilizado como fotosensibilidazor en la generación de oxígeno singlete. Este SOC con fulereno atrapado, fue capaz de oxidar una gran variedad de alquenos utilizando el oxígeno singlete generado a partir de aire a presión atmosférica y luz visible. Finalmente se encapsularon multiples guests.Three nickel-based and one palladium-based supramolecular organometallic cages have been prepared. These four cages are based on a N-heterocyclic carbene ligand with a pyrene tag, that has been key in the subsequent applications of the cage together with the inner cavity. By pi-stacking interactions, it has been possible to encapsulate both polycylic aromatic hydrocarbons and fullerenes. The interest on first group of compounds is based on their accurate toxicity while the fullerenes are interesting due to their added value. It was possible to extract the first group of molecules from an organic media through the encapsulation inside the supramolecular cages. The host-guest adduct formed with fullerenes encapsulated inside the palladium cage was used as photocatalyst of aromatic, cyclic and acyclic substrates via singlet oxygen generation. The same palladium cage was used as receptor for multiple stacks of polyaromatic compounds.Programa de Doctorat en Cièncie

    Oxidation triggers guest dissociation during reorganization of an FeII 4L6 twisted parallelogram.

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    A three-dimensional FeII 4L6 parallelogram was prepared from ferrocene-containing ditopic ligands. The steric preference of the bulky ferrocene cores towards meridional vertex coordination brought about this new structure type, in which the ferrocene units adopt three distinct conformations. The structure possesses two distinct, bowl-like cavities that host anionic guests. Oxidation of the ferrocene FeII to ferrocenium FeIII causes rotation of the ferrocene hinges, converting the structure to an FeII 1L1 + species with release of anionic guests, even though the average charge per iron increases in a way that would ordinarily increase guest binding strength. The degrees of freedom exhibited by these new structures - derived from the different configurations of the three ligands surrounding a meridional FeII center and the rotation of ferrocene cores - thus underpin their ability to reconfigure and eject guests upon oxidation

    Total Absortion Spectroscopy of Fission Fragments Relevant for Reactor Antineutrino Spectra Determination

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    8 pags., 3 figs., 1 tab. ; Presented at the XXXIV Mazurian Lakes Conference on Physics, Piaski, Poland, September 6–13, 2015.The contribution of each fission fragment to the reactor antineutrino spectra was determined using the summation method based on the existing information on fission yields and decay data contained in nuclear databases and the reactor evolution code MURE. The beta decay of some of the main contributors has been studied using the Total Absorption Spectroscopy (TAS) technique during two experimental campaigns at the IGISOL facility, in Jyväskylä (Finland). Results on the decay of 92Rb, the most important contributor in the 4–8 MeV energy region are reported. The status of the analysis of the second experiment is presented as well.Peer Reviewe

    Characterization of a cylindrical plastic β-detector with Monte Carlo simulations of optical photons

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    V. Guadilla et al. -- 5 pags., 8 figs., tab.In this work we report on the Monte Carlo study performed to understand and reproduce experimental measurements of a new plastic β-detector with cylindrical geometry. Since energy deposition simulations differ from the experimental measurements for such a geometry, we show how the simulation of production and transport of optical photons does allow one to obtain the shapes of the experimental spectra. Moreover, taking into account the computational effort associated with this kind of simulation, we develop a method to convert the simulations of energy deposited into light collected, depending only on the interaction point in the detector. This method represents a useful solution when extensive simulations have to be done, as in the case of the calculation of the response function of the spectrometer in a total absorption γ-ray spectroscopy analysis.This work has been supported by the Spanish Ministerio de Economía y Competitividad under grants FPA2011-24553, AIC-A-2011-0696, FPA2014-52823-C2-1-P and the program Severo Ochoa (SEV-2014-0398), by the European Commission under the FP7/EURATOM contract 605203, and by the Spanish Ministerio de Educación under the FPU12/01527 grant.Peer Reviewe
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