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11.
After heat erases the order in 1,3-O,O'-bis(dodecyl)calix[4]arene, it self-organizes the phenyl units into a rigid calix bowl first at T2 = 111 degrees C, followed by the formation of all-trans alkyl chains at T1 = 62 degrees C, which eventually yields a stable cone-shaped structure at room temperature. 相似文献
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[reaction: see text] Electrooptical sensors consisting of a conjugated chromophore undergoing a change in color and a redox-active moiety such as quinone fused to the chromophore were synthesized. Strong changes in colorimetric and electrochemical properties were observed in the presence of inorganic anions. A unique anion-specific response was observed for fluoride, pyrophosphate, and acetate. DFT (B3LYP/6-31G) calculations performed for both "on/off" states of a sensor-fluoride model are in good agreement with the observed electrochemical and spectroscopic data. 相似文献
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[reaction: see text] The biomimetic synthesis of the bisesquiterpenoids biatractylolide 1 and biepiasterolide 2 is reported. 相似文献
16.
Ana Egatz-Gómez P. Aella P. Domínguez-García S.T. Picraux Miguel A. Rubio Manuel Marquez Antonio A. García 《Applied Surface Science》2007,254(1):330-334
A microfluidic method to manipulate small drops of water is studied on two different superhydrophobic surfaces. Using this digital magnetofluidic method, water drops containing paramagnetic carbonyl-iron microparticles were displaced on silicon nanowire (Si NW) and low-density polyethylene (LDPE) superhydrophobic surfaces using magnetic fields. Horizontal, vertical, or upside-down drop movement is made possible by the action of capillary forces induced by paramagnetic particles aligning and following a magnetic field, indicating that three-dimensional digital microfluidics is possible. Also, both Si NW and LDPE superhydrophobic surfaces combine surface chemistry with nano and microscale surface roughness to make drop movement possible. Si NW superhydrophobic surfaces were prepared using vapor-liquid-solid growth systems followed by coating with a perfluorinated hydrocarbon. LDPE superhydrophobic surfaces were prepared by growing polyethylene crystals on a polyethylene substrate through careful rate control. 相似文献
17.
Carolina G. Dos Santos Daniela T. Marquez Charles-Oneil L. Crites Jose Carlos Netto-Ferreira Juan C. Scaiano 《Tetrahedron letters》2017,58(5):427-431
Two different hybrid materials composed of gold nanoparticles (AuNPs) supported on either commercial niobium oxide HY 340 or mesoporous niobium oxide catalyzed the Friedel-Crafts alkylation of anisole by benzyl chloride. Excitation of the surface plasmon of the supported AuNPs allowed the reaction to occur at lower temperatures by acting as an alternative heat source. The localized heating produced via plasmon excitation permitted the acid catalyzed reaction to occur - at the Lewis acid sites on the Nb2O5 support - at 80 °C while thermal-dark reactions using a conventional heat source, required temperatures of 120 °C or higher. The catalytic activity of the tested hybrid materials decreased with storage time. However, the deactivation showed to be reversible upon lyophilisation indicating that the nature of the deactivation could be due to water adsorption. 相似文献
18.
Moon HR Siddiqui MA Sun G Filippov IV Landsman NA Lee YC Adams KM Barchi JJ Deschamps JR Nicklaus MC Kelley JA Marquez VE 《Tetrahedron》2010,66(34):6707-7430
Steric and electronic parameters, such as the anomeric effect (AE) and gauche effect play significant roles in steering the North⇆South equilibrium of nucleosides in solution.Two isomeric oxa-bicyclo[3.1.0]hexane nucleosides that are conformationally locked in either the North or the South conformation of the pseudorotational cycle were designed to study the consequences of having the AE operational or not, independent of other parameters. The rigidity of the system allowed the orientation of the orbitals involved to be set in ‘fixed’ relationships, either antiperiplanar where the AE is permanently ‘on’, or gauche where the AE is impaired. The consequences of these two alternatives were subjected to high-level calculations and measured experimentally by X-ray crystallography, hydrolytic stability of the glycosyl bond, and pKa values. 相似文献
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Gil V. J. da Silva Mauricio G. Constantino Cláudio F. Tormena R. Thomas Williamson Brian L. Marquez 《Magnetic resonance in chemistry : MRC》2007,45(3):282-282
The original article to which this Erratum refers was published in Magnetic Resonance in volume 45 issue 1. 相似文献