Buscador

Found 12 result(s)
Found 2 page(s)

Promoting Intermolecular C-N Bond Formation under the Auspices of Iodine(III)

  • Muñiz, Kilian
The quest for the development of new protocols that provide general conditions for oxidative carbon–nitrogen bond formation has grown over recent years. Within this context, due to feasibility and benignity considerations in biochemical sciences, reactions that rely on main group oxidants as the only promoters have received particular interest. We have recently found that simple protonolysis events enable the incorporation of nitrogenated groups of the bissulfonimide family into the coordination sphere of common iodine(III) complexes such as diacetoxy iodobenzene. The products of the type ArI(OAc)(NTs2) represent rare examples of iodine(III) compounds displaying reactive iodine–nitrogen single bonds. Further protonolysis furnishes the corresponding iodine(III) compounds ArI(NTs2)2 containing two defined iodine–nitrogen single bonds for unprecedented dual transfer of both nitrogenated groups. It is of great synthetic importance that these new compounds contain iodine–nitrogen entities, which upon dissociation in solution lead to electrophilic iodine centers and nucleophilic nitrogen groups. This has enabled the development of a body of conceptually new amination reactions, which do not rely on conventional electrophilic nitrogen reagents but rather employ iodine(III) as an electrophilic activator and bissulfonimides as the source of subsequent nucleophilic amination. Additional diversification arises from the ambident nature of bissulfonimines enabling oxygenation pathways. The exciting chemistry covered in this Account comprises structural features of the reagents (including X-ray analysis), scope and limitation in synthetic amination of different hydrocarbons (including sp-, sp2-, and sp3-hybridized centers as in acetylenes, alkenes, enols, butadienes, allenes, arenes, and alkylketones), and physical-organic and theoretical analysis of the underlying reaction mechanisms. The oxidative transformations with all their rich diversifications originate from the versatile redox chemistry of the iodine(III) and iodine(I) pair, which shares several aspects of transition metal high oxidation state chemistry. For the present aryliodine(III) reagents, steric and electronic fine-tuning is possible through accurate engineering of the arene substituent. In addition to the general reactivity of the I–N bond, chiral aryliodine(III) reagents with defined stereochemical information in the aryl backbone are conceptually compatible with this approach. Thus, the development of enantioselective amination reactions with up to 99% ee was also successful. Several of the active enantioselective reagents have been isolated and structurally characterized. Following this approach for the important class of chiral vicinal diamines, an unprecedented direct diamination of alkenes could be conducted in an enantioselective catalytic manner under full intermolecular reaction control. This latter reaction is based on the precise engineering of a chiral aryliodine(III) catalyst in combination with bismesylimide as nitrogen source. It is the consequence of the precise understanding of the reaction behavior of structurally defined bisimidoiodine(III) reagents.
Project:


IN-SPACE: УЧИМСЯ ПРИДАВАТЬ ПРОСТРАНСТВУ ФОРМУ

  • Madrazo Agudín, Leandro
  • Costa Jutglar, Gonçal
Is it possible to isolate inner space from the need to see it as a volume from outside and to concentrate on the design of space itself? IN-SPACE is a web-based modelling tool especially conceived to give form to space, within space itself. With this tool, space is shaped from within, as we move through it expanding and contracting its limits. Starting from a cell located at the center of a three-dimensional grid, voids are carved by projecting the position of the viewer outwards along each of the three axes. As the avatar moves in this grid, space is being shaped. Conversely, voids can be undone projecting the position of a cell inwards towards the position of the view. Sounds, images and texts can be added to the cells that make a space. Once a space is created, the avatar can move inside the space or it can be driven automatically along the paths that have generated the space. Architecture students use this tool to develop their capacities of space conception as well as of space perception and orientation.
Project:


A century of fascism in Spain, 1918-2014

  • Casals, Xavier
The history of fascism in Spain tends to be presented in a standard chronological pattern that begins in 1933 with the creation of the Falange Española party, and follows with its subsequent development during the Civil War (1936-1939), and under the dictatorship of general Francisco Franco (1939-1975). This study offers a different perspective, beginning in 1918, with the appearance of the first fascist organization in Barcelona, and ends with an analysis of the legacy of fascism in today’s extreme right.
Project:


Measurement of the time-integrated CP asymmetry in D 0 → K 0S K 0S decays

  • Badalov, Alexey
  • Calvo Gómez, Míriam
  • Vilasís Cardona, Xavier
  • LHCb Collaboration - CERN
The time-integrated CP asymmetry in the decay D 0 → K 0S K 0S is measured using 3 fb−1 of proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. The flavour of the D 0 meson is determined by use of the decay D *+ → D 0 π + and its charge conjugate mode. The result is ACP=−0.029±0.052±0.022, where the first uncertainty is statistical and the second systematic. The result is consistent with Standard Model expectations and improves the uncertainty with respect to the only previous measurement of this quantity by more than a factor of three.
Project:


Culturele apartheid in leergangen Nederlands als vreemde taal

  • Raemdonck, Anne Van
This article looks at the way culture is represented in 3 commonly used course books of Dutch as a foreign language. According to the author, everyday culture of the regions where Dutch is spoken, is presented from a nationalistic point of view, i.e. it is limited to either cultural, historical and social aspects of The Netherlands or cultural, historical and social aspects of the Flemish Community in Belgium. The existence of the other region or country where the same language is spoken is not only ignored but at times even portrayed wrongfully which has its logically negative effect upon the students" interpretation and can lead to prejudice and the teachers using those course books.
Project:


Analysis of the gap between new hotel technologies and guests' ability to use them

  • Garcia Vilchez, Yaiza
The purpose of this study was to analyze the gap between the new technologies that the hotels offer to their guest and their ability or knowledge to use these technologies. With this study the hoteliers will be able to identify when exist a digital divide risk with their guests. Since, nowadays do not always match the technologic services offered by the hotels and the guest technological needs and abilities. This gap will be detect by the analysis of the hotel and of the guest based on the three main variables that affect the digital divide. To develop this study, firstly, a deductive theoretical part of the research question has been done, by analyzing the background of the digital divide, detecting and analyzing his main variables and an analyzing the technological services offered in the lodging industry. Secondly, to develop the fieldwork, a quantitative technique was used by collecting secondary data and using the sampling technique. Once analyzed the data collected it was possible to conclude that an hotelier can detect the gap between the guest technological domain and the technology offered by the hotel. In addition to that, it was possible to find out that the digital divide has three main variables, which are the geographic, generation and economic variable and also was possible to classify the hotels and guests based on these variables. Besides, it has been found out that the digital divide it is bigger when a guest is traveling and staying in a hotel of his or her same country than when is traveling to another country of their culture or continent. In addition, after the analysis of the results it can be also concluded that the economic variable it is very influential in the digital divide. Afterwards, some recommendations and further work were pointed out in order to continue improving on the detection of the digital divide on the lodging industry.
Project:


Advanced search