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11.
Y. Arroyo Gómez J. A. López Sastre J. F. Rodríguez Amo M. A. Sanz Tejedor 《Journal of carbohydrate chemistry》2013,32(7):1051-1058
Abstract The asymmetric oxidation reaction of D-glyceraldehyde diethyl dithioacetal 1 and its di-O-acetyl derivative with a Sharpless reagent to produce the corresponding D-glyceraldehyde diethyl dithioacetal S-oxide derivatives takes place with high stereoselectivity. The configuration of the two new chiral centres formed is deduced. 相似文献
12.
López-Martín J Anam EM Boira H Sanz MJ Blázquez MA 《Chemical & pharmaceutical bulletin》2002,50(12):1613-1615
Dennettine, a new 2,6-dimethoxychromone and three known phenanthrene alkaloids (uvariopsine, stephenanthrine and argentinine) in addition to the phenolic and known compound vanillin were isolated from the roots of Dennettia tripetala. Their structures were determined by physical and spectroscopical one dimensional (1D) and 2D-NMR analysis, including heteronuclear multiple bond correlation and nuclear Overhauser enhancement spectroscopy. 相似文献
13.
Sastre G Vidal-Moya JA Blasco T Rius J Jordá JL Navarro MT Rey F Corma A 《Angewandte Chemie (International ed. in English)》2002,41(24):4722-4726
14.
T. Susdorf D. del Agua A. Tyagi A. Penzkofer O. García R. Sastre A. Costela I. García-Moreno 《Applied physics. B, Lasers and optics》2007,86(3):537-545
Samples of dipyrromethene-BF2 dye PM597 incorporated in copolymers of 3-(trimethoxysilyl)propyl methacrylate (TMSPMA) with methyl methacrylate (MMA) and
2-hydroxyethylmethacrylate (HEMA), and in terpolymers of MMA, HEMA and TMSPMA are characterized. The absorption cross-section
spectra, stimulated emission cross-section spectra, and the excited-state absorption cross-section at 527 nm are determined.
The fluorescence quantum distributions and fluorescence lifetimes are measured. The photo-degradation is studied under cw
laser excitation conditions and quantum yields of photo-degradation are extracted. PM597 solid state samples are compared
with PM597 in liquid ethyl acetate solution. The fluorescence quantum yield of PM597 is higher in doped samples (around 70%)
compared to PM597 in ethyl acetate (43%). The excited-state absorption cross-section was found to be negligibly small. The
photo-stability is considerably larger in the polymeric samples compared to the liquid solutions.
PACS 42.55.-f; 78.45.+h; 78.55.-m; 78.40.Me 相似文献
15.
Leonardo Maestri Teixeira Aaron Strickland Sonny S. Mark Magnus Bergkvist Yajaira Sierra‐Sastre Carl A. Batt 《Macromolecular bioscience》2010,10(2):147-155
S‐Layer proteins are an example of bionanostructures that can be exploited in nanofabrication. In addition to their ordered structure, the ability to self‐assembly is a key feature that makes them a promising technological tool. Here, in vitro self‐assembly kinetics of SpbA was investigated, and found that it occurs at a rate that is dependent on temperature, its concentration, and the concentration of calcium ions and sodium chloride. The activation enthalpy (120.81 kJ · mol?1) and entropy (129.34 J · mol?1 · K?1) obtained infers that the incorporation of monomers incurs in a net loss of hydrophobic surface. By understanding how the protein monomers drive the self‐assembly at different conditions, the rational optimization of this process was feasible.
16.
J. M. Sanz Báñez J. A. Sastre López M. R. Molina Patiño T. Gómez Santacana C. Romero-Ávila García 《Journal of carbohydrate chemistry》2013,32(4):403-417
ABSTRACT The synthesis of several 3-aryl-5-glycosylisoxazole derivatives has been achieved. By condensation of the protected aldehydo-sugars 2,3-O-isopropylidene-D-glyceraldehyde (1), 2,3:4,5-di-O-isopropylidene-aldehydo-D-arabinose (2) and D-xylose (3), and 2,5-anhydro-3,4,5-tri-O-benzoyl-D-mannose (4) with benzoylmethylenetriphenylphosphorane, enulose derivatives were formed, which were later converted into a,ß-unsaturated ketoximes. These ketoximes were oxidatively cyclized with iodine and, after removal of the hydroxyl protecting groups, 3-phenyl-5-glycosylisoxazoles were formed. 相似文献
17.
J. A. López Sastre J. F. Rodríguez Amo J. M. Báñez Sanz J. Molina Molina M. C. Romero-Avila A. Sanz Tejedor 《Journal of carbohydrate chemistry》2013,32(3):291-308
Abstract The reaction of 2,3-O-isopropylidene-D-glyceraldehyde with different dialkyl and diarylthiomethyl sulfoxides occurs with a high selectivity and produces the corresponding 1-alkyl(or l-aryl)-sulfynil-l-alkyl(or 1-aryl) thio-3,4-O-isopropylidene-D-tetroses as pure diastereoisomers. We have determined the absolute configuration of the three chiral centers formed in these reactions. 相似文献
18.
Thin films of indocyanine green J-aggregates in polymers have been prepared and their saturable absorption properties studied
in a high intensity regime using a unique ultrashort pulse Ti:sapphire laser (10 fs) with a very broad bandwidth (over 200 nm
at -20 dB). The samples showed a surprisingly high stability to irradiation, strong absorption bleaching, and wavelength dependent
differential absorption spectra.
PACS 42.70 Jk; 42.65.-k; 78.66.Qu 相似文献
19.
The adsorption of hydrogen in MOFs takes place mainly close to the inorganic secondary building unit (IBU). The adsorption capacities on MIL-88, UiO-66, MIL-47 and MFU-1 were investigated. Quantum chemical calculations at the ab initio HF/MP2 theoretical level were employed to estimate the maximum uptake of H(2) molecules per metallic centre. Extrapolating the results on small clusters to the unit cell of each particular MOF, the H(2) uptakes (gravimetric and volumetric) were estimated. The loading of hydrogen per metal atom (H(2) molecules/M-atom) and the density of metal atoms (M-atoms ?(-3)) were defined as useful parameters to assess hydrogen storage properties and to estimate the optimum density that the material should have to be a good H(2) adsorbent. It was found that values above 3 H(2) molecules/M-atom and around 0.004 M-atoms ?(-3) for MOFs with densities around 0.7-1.0 g cm(-3) are required to reach the 2015 storage targets. 相似文献
20.
Michael M. Tung Javier Ibáñez Emilio Defez Jorge Sastre 《Mathematical Methods in the Applied Sciences》2020,43(14):8237-8252
This work deals with the simulation of a two-dimensional ideal lattice having simple tetragonal geometry. The harmonic character of the oscillators give rise to a system of second-order linear differential equations, which can be recast into matrix form. The explicit solutions which govern the dynamics of this system can be expressed in terms of matrix trigonometric functions. For the derivation we employ the Lagrangian formalism to determine the correct solutions, which extremize the underlying action of the system. In the numerical evaluation we develop diverse state-of-the-art algorithms which efficiently tackle equations with matrix sine and cosine functions. For this purpose, we introduce two special series related to trigonometric functions. They provide approximate solutions of the system through a suitable combination. For the final computation an algorithm based on Taylor expansion with forward and backward error analysis for computing those series had to be devised. We also implement several MATLAB programs which simulate and visualize the two-dimensional lattice and check its energy conservation. 相似文献