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91.
92.
Maurizio Sansotera Cristian Gambarotti Antonino Famulari Alberto Baggioli Raffaella Soave Francesco Venturini Stefano V. Meille Ivan Wlassics Walter Navarrini 《Tetrahedron》2014
Perfluoroalkyl radicals, generated by thermal decomposition of perfluorodiacyl peroxides, react selectively with quinone rings of 1,4-naphthoquinones. In the presence of a non-conjugated alkene such as 1-hexene, perfluoroalkyl radicals add to the double bonds of the olefin forming a radical adduct, which selectively adds to the naphthoquinone ring. Several perfluorodiacyl peroxides have been synthesized and used for the direct and alkene-mediated functionalization of naphthoquinones. Geometrical parameters and electron density topology of all perfluorodiacyl peroxides have been calculated by the density functional formalism and quantum theory of atoms in molecules to attempt a rationalization of the experimental reactivity. 相似文献
93.
Multiresidue analysis of quinolones in water by ultra‐high perfomance liquid chromatography with tandem mass spectrometry using a simple and effective sample treatment
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Manuel Lombardo‐Agüí Carmen Cruces‐Blanco Ana M. García‐Campaña Laura Gámiz‐Gracia 《Journal of separation science》2014,37(16):2145-2152
A rapid and simple analytical method has been developed for the determination of 19 quinolones in environmental water samples using ultra high performance liquid chromatography with tandem mass spectrometry. Chromatographic and detection conditions have been optimized and the separation was achieved in less than 4 min. The separation was carried out using a new‐generation column filled with superficially porous particles, resulting in lower backpressure and better resolution than totally porous particle columns. The quinolones were detected by electrospray ionization in positive mode using multiple‐reaction monitoring mode for acquisition. A sample treatment based on liquid–liquid extraction and phase separation via salting‐out was employed to achieve a fast and simple extraction that enables the multiresidue analysis. The method has been validated for an environmental well water sample from a mountain area. Very low limits of detection (between 10 and 90 ng/L) with relative standard deviations lower than 16.5% and recoveries higher than 73% were achieved. Moreover, well waters from different origins (mountain and coast areas and irrigated land) have been evaluated and similar results were obtained. 相似文献
94.
Mihaela Vlassa Gheorghe Borodi Cristian Silvestru Mircea Vlassa 《Central European Journal of Chemistry》2014,12(1):14-24
Reaction of Na4TCM (1) (H4TCM = tetra[4-(carboxyphenyl)oxamethyl]methane) with [Cu(CHA)](ClO4)2 (2)(CHA = 1,3,6,8,11,14-hexaaz atricyclo[12.2.1.1.8,11] octadecane) in a DMF-water mixture yields [Cu(CHA)]2[TCM] (3). Structural analysis of [Cu(CHA)]2[TCM]·11H2O (3·11H2O) by single crystal X-ray diffraction reveals strong copper-oxygen bonds between two complex cations and the tetraanion leading to a 3D coordination network (zwitterionic structure), consolidated through additional NH...O=C hydrogen bonding within the cation/anion association. The resulting coordination geometry around a copper atom is a distorted square pyramidal with an oxygen atom of the anionic ligand in the apical position. A 3D supramolecular network is developed in the crystal based only on NH...OC hydrogen bonds between the macrocyclic metallic tecton and the carboxylate groups of neighboring 3D coordinated (zwitterionic) moieties. The pseudotetrahedral TCM4? tetraanionic ligand induces a diamondoid architecture formed of large distorted adamantanoid cages. 相似文献
95.
José Grau Cristian Azorín Juan L. Benedé Alberto Chisvert Amparo Salvador 《Journal of separation science》2022,45(1):210-222
Dispersive liquid-liquid microextraction is one of the most widely used microextraction techniques currently in the analytical chemistry field, mainly due to its simplicity and rapidity. The operational mode of this approach has been constantly changing since its introduction, adapting to new trends and applications. Most of these changes are related to the nature of the solvent employed for the microextraction. From the classical halogenated solvents (e.g., chloroform or dichloromethane), different alternatives have been proposed in order to obtain safer and non-pollutants microextraction applications. In this sense, low-density solvents, such as alkanols, switchable hydrophobicity solvents, and ionic liquids were the first and most popular replacements for halogenated solvents, which provided similar or better results than these classical dispersive liquid-liquid microextraction solvents. However, despite the good performances obtained with low-density solvents and ionic liquids, researchers have continued investigating in order to obtain even greener solvents for dispersive liquid-liquid microextraction. For that reason, in this review, the evolution over the last five years of the three types of solvents already mentioned and two of the most promising solvent alternatives (i.e., deep eutectic solvents and supramolecular solvents), have been studied in detail with the purpose of discussing which one provides the greenest alternative. 相似文献
96.
Cristian Mauricio Barreto Pinilla Nathalie Almeida Lopes Adriano Brandelli 《Molecules (Basel, Switzerland)》2021,26(12)
Encapsulation can be a suitable strategy to protect natural antimicrobial substances against some harsh conditions of processing and storage and to provide efficient formulations for antimicrobial delivery. Lipid-based nanostructures, including liposomes, solid lipid nanoparticles (SLNs), and nanostructured lipid nanocarriers (NLCs), are valuable systems for the delivery and controlled release of natural antimicrobial substances. These nanostructures have been used as carriers for bacteriocins and other antimicrobial peptides, antimicrobial enzymes, essential oils, and antimicrobial phytochemicals. Most studies are conducted with liposomes, although the potential of SLNs and NLCs as antimicrobial nanocarriers is not yet fully established. Some studies reveal that lipid-based formulations can be used for co-encapsulation of natural antimicrobials, improving their potential to control microbial pathogens. 相似文献
97.
Castro Jorge Fernández Francisco Olivares Felipe Berríos Cristhian Garrido-Ramírez Elizabeth Blanco Elodie Escalona Néstor Aspée Alexis Barrías Pablo Ureta-Zañartu M. Soledad 《Journal of Solid State Electrochemistry》2021,25(1):117-131
Journal of Solid State Electrochemistry - 2,4,6-trichlorophenol (TCP) is a persistent pollutant introduced in water by industrial processes and pesticides. We have studied the electrooxidation of... 相似文献
98.
The B-factor index for the binding site (BFIbs) to prioritize crystal protein structures for docking
Structural Chemistry - In cheminformatics, protein-ligand docking is a powerful tool applied for virtual screening, pose prediction, and binding affinity estimation. However, docking results depend... 相似文献
99.
Sapienza R García PD Bertolotti J Martín MD Blanco A Viña L López C Wiersma DS 《Physical review letters》2007,99(23):233902
In this Letter we demonstrate Mie resonances mediated transport of light in randomly arranged, monodisperse dielectric spheres packed at high filling fractions. By means of both static and dynamic optical experiments we show resonant behavior in the key transport parameters and, in particular, we find that the energy transport velocity, which is lower than the group velocity, also displays a resonant behavior. 相似文献
100.
Accurate control of a liquid-crystal display to produce a homogenized Fourier transform for holographic memories 总被引:1,自引:0,他引:1
Márquez A Gallego S Méndez D Alvarez ML Fernández E Ortuño M Neipp C Beléndez A Pascual I 《Optics letters》2007,32(17):2511-2513
We show an accurate procedure to obtain a Fourier transform (FT) with no dc term using a commercial twisted-nematic liquid-crystal display. We focus on the application to holographic storage of binary data pages, where a drastic decrease of the dc term in the FT is highly desirable. Two different codification schemes are considered: binary pi radians phase modulation and hybrid ternary modulation. Any deviation in the values of the amplitude and phase shift generates the appearance of a strong dc term. Experimental results confirm that the calculated configurations provide a FT with no dc term, thus showing the effectiveness of the proposal. 相似文献