Search results for "Solid-State"
showing 10 items of 530 documents
Innovative Approaches for Light-Emitting Electrochemical Cells
2023
El uso de nuevos materiales, como las moléculas emisoras de luz o los polímeros transportadores de iones, tiene una importancia fundamental a la hora de mejorar la vida útil o de conseguir altos niveles de luminancia en dispositivos de tipo LEC. Al mismo tiempo, los avances más recientes han llevado a la tecnología LED y OLED a una nueva clase de dispositivos con propiedades atractivas, como la flexibilidad o la transparencia, desarrollo que se ha llevado a cabo de forma muy limitada en los LECs. Teniendo esto en cuenta, el trabajo de esta Tesis se centró en la implementación de nuevos materiales, en particular nuevos emisores iTMC y un polímero conductor iónico, y el diseño y fabricación d…
4,4'-[Thiophene-2,5-diylbis(ethyne-2,1-diyl)]dibenzonitrile
2008
In the solid state, the title compound, C(22)H(10)N(2)S, forms centrosymmetric dimers by pairs of non-classical C-H⋯S hydrogen bonds linking approximately coplanar mol-ecules. The benzene ring involved in this inter-action makes a dihedral angle of only 7.21 (16)° with the thio-phene ring, while the other benzene ring is twisted somewhat out of the plane, with a dihedral angle of 39.58 (9)°. The hydrogen-bonded dimers stack on top of each other with an inter-planar spacing of 3.44 Å. C-H⋯N hydrogen bonds link together stacks that run in approximately perpendicular directions. Each mol-ecule thus inter-acts with 12 adjacent mol-ecules, five of them approaching closer than the sum of the van …
Inside Cover: Hydrogen-Bonded Open-Framework with Pyridyl-Decorated Channels: Straightforward Preparation and Insight into Its Affinity for Acidic Mo…
2017
International audience; A hydrogen-bonded open framework with pores decorated by pyridyl groups was constructed by off-charge-stoichiometry assembly of protonated tetrakis(4-pyridyloxymethyl)methane and [Al(oxalate)(3)](3-), which are the H-bond donor and acceptor of ionic H-bond interactions, respectively. This supramolecular porous architecture (SPA-2) has 1nm-large pores interconnected in 3D with large solvent-accessible void (53%). It demonstrated remarkable affinity for acidic organic molecules in solution, which was investigated by means of various carboxylic acids including larger drug molecules. Competing sorption between acetic acid and its halogenated homologues evidenced good sel…
The pentafluorophenyl group as π-acceptor for anions: a case study
2015
Chemical science 6(1), 354-359 (2015). doi:10.1039/C4SC02762K
The Missing Member of the Partially O-Alkylated Resorcinarene Family: Synthesis and Conformation of Methyl Tetramethoxy Resorcinarene
2013
An improved Lewis acid catalyzed synthesis method for methyl tetramethoxy resorcinarene is described, which produced the missing lower rim methyl derivative of this partially O-alkylated resorcinarene family. Structural characterization by means of variable temperature NMR experiments and single crystal X-ray diffraction studies furthermore revealed that the resorcinarene core adopts different conformations in the solid state and in solution. peerReviewed
Entrapment of a linear water pentamer into a uranyl-salophen dimer in the solid state
2019
In the solid state, uranyl-salophen complex 1, decorated with bipyridyl sidearms, self-assembles from moist acetonitrile into dimeric species displaying a confined water pentamer, as observed by X-...
Gallium preference for the occupation of tetrahedral sites in Lu3(Al5-xGax)O12multicomponent garnet scintillators according to solid-state nuclear ma…
2019
Abstract In this study, the distributions of aluminum and gallium atoms over the tetrahedral and octahedral sites in the garnet structure were investigated in mixed Lu3Al5-xGaxO12 crystals by using 27Al and 71Ga magic angle spinning nuclear magnetic resonance (NMR) and single crystal 71Ga NMR. The experimental study was supported by theoretical calculations based on density functional theory (DFT) in order to predict the trends in terms of the substitutions of Al by Ga in the mixed garnets. Both the experimental and theoretical results indicated the non-uniform distribution of Al and Ga over the tetrahedral and octahedral sites in the garnet structure, with a strong preference for Ga occupy…
Influence of Nitrogen Doping on Device Operation for TiO₂-Based Solid-State Dye-Sensitized Solar Cells: Photo-Physics from Materials to Devices.
2015
Solid-state dye-sensitized solar cells (ssDSSC) constitute a major approach to photovoltaic energy conversion with efficiencies over 8% reported thanks to the rational design of efficient porous metal oxide electrodes, organic chromophores, and hole transporters. Among the various strategies used to push the performance ahead, doping of the nanocrystalline titanium dioxide (TiO2) electrode is regularly proposed to extend the photo-activity of the materials into the visible range. However, although various beneficial effects for device performance have been observed in the literature, they remain strongly dependent on the method used for the production of the metal oxide, and the influence o…
Spin-lattice relaxation of deuterated methyl groups: Implications of the pauli principle
1999
The high-field spin-lattice relaxation of deuterated methyl groups undergoing rotational tunneling is investigated theoretically. It is found that for systems showing a tunneling frequency comparable to accessible Larmor frequencies the relaxation to equilibrium of the Zeeman energy does not follow a simple exponential time dependence even in powdered samples due to a finite coupling to the relaxation of the tunneling system. This finding contrasts to the high-temperature behavior of reorienting methyl groups which undergo simple exponential relaxation. The nonexponentiality has its origin in the statistical coupling of the three deuteron spins due to the Pauli principle.
Crystal structures of 4-chloro-pyridine-2-carbo-nitrile and 6-chloro-pyridine-2-carbo-nitrile exhibit different inter-molecular π-stacking, C-H⋯Nnitr…
2015
The crystal structures of two chlorocyanopyridines, namely 4-chloropyridine-2-carbonitrile and 6-chloropyridine-2-carbonitrile, exhibit unique intermolecular C—H⋯Nnitrile, C—H⋯Npyridine and offset face-to-face π-stacking interactions.