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71.
72.
Niki Baccile Anna Fischer Beatriz Julián-López David Grosso Clément Sanchez 《Journal of Sol-Gel Science and Technology》2008,47(2):119-123
Core-shell and homogeneous distributions of functionalized cerium oxide nanoparticles within spray-dried mesostructured silica
spheres are achieved by modification of synthesis parameters such as the templating agent and nanoparticle capping functions.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
相似文献
Clément Sanchez (Corresponding author)Email: |
73.
Tolosa J Romero-Nieto C Díez-Barra E Sánchez-Verdú P Rodríguez-López J 《The Journal of organic chemistry》2007,72(10):3847-3852
The efficient synthesis of new asymmetric poly(phenylenevinylene) dendritic macromolecules using a stepwise convergent-growth approach is described. By an iterative methodology that made use of the Horner-Wadsworth-Emmons (HWE) reaction, dendrons and dendrimers up to the third generation, with eight different functional groups located at the periphery, were prepared in good yields. Both the number and placement of functionalities can be accurately controlled to afford a large variety of dendritic architectures. 相似文献
74.
Mariana Barturen Mahmoud Eddrieff Julián Milano Sebastián Bustingorry Horia Popescu Nicolas Jaouen Fausto Sirotti Massimiliano Marangolo 《The European Physical Journal B - Condensed Matter and Complex Systems》2013,86(4):191
We show by a combined magnetic force microscopy and synchrotron radiation spectroscopy study that stripe-like patterned magnetic domains are present in Fe1?x Ga x thin films. These stripes, whose origin is attributed to an out-of-plane magnetic component, can be rotated by an external magnetic field. 相似文献
75.
Hadad C Achelle S García-Martinez JC Rodríguez-López J 《The Journal of organic chemistry》2011,76(10):3837-3845
A series of 4-arylvinyl-2,6-di(pyridin-2-yl)pyrimidines have been efficiently prepared by a double cross-coupling reaction between 2,4-dichloro-6-methylpyrimidine and 2-(tributylstannyl)pyridine, followed by aldol condensation with the appropriate aromatic aldehyde substituted with electron-donating, electron-withdrawing, dendritic, or water-soluble groups. The effect of different protic and aprotic solvents on the optical absorption and emission properties of these systems was studied. Compounds with electron-donating groups display strong emission solvatochromism, suggesting the formation of an intramolecular charge-separated emitting state. The solvatochromic behavior depends not only on the solvent polarity but also on the hydrogen bonding parameters of the solvent. The effect of protonation was also studied, and the abilities of some of these molecules to function as colorimetric and luminescent pH sensors were demonstrated with dramatic color changes and luminescence switching upon the introduction of acid. 相似文献
76.
Xabier Rios Paula Moriones Jesús C. Echeverría Asunción Luquín Mariano Laguna Julián J. Garrido 《Adsorption》2011,17(3):583-593
The mild synthetic conditions provided by the sol-gel process and the versatility of the colloidal state allow for the mixing
of inorganic and organic components at the nanometre scale in virtually any ratio for the preparation of hybrid materials.
Our interest in hybrid xerogels focuses on combining their porosity with other properties to prepare optic-fibre sensors.
The specific aim of this paper is to synthesise hybrid xerogels in acid media using methyltriethoxysilane (MTEOS) and tetraethoxysilane
(TEOS) as silica precursors and to investigate the effect of the MTEOS molar ratio on the structure and porous texture of
xerogels. Gelation time exponentially increased as the MTEOS molar ratio increased. Increasing the MTEOS molar ratio yielded
xerogels with lower density and lower particle size. The incorporation of MTEOS resulted in new FTIR bands at 1276 and 791 cm−1, which was attributed to vibrational modes of methyl group. The band around 1092 cm−1 associated with siloxane bonds shifted to lower wavenumbers and split into two bands. The 29Si spectra only showed the Q
n
(n=2, 3, 4) signal in xerogels with 0% MTEOS and the T
n
(n=2, 3) signal in xerogels with 100% MTEOS; hybrid xerogels showed both Q and T signals. From XRD peaks at 2θ around 9°, we inferred that xerogels (>70% MTEOS) consisted of nanocrystalline CH3–SiO3/2 species. Increasing the MTEOS molar ratio produced xerogels with lower pore volumes and lower average pore size. The integration
of methyl groups on the surface decreased the surface polarity and, in turn, the characteristic energy. 相似文献
77.
Carlos LD Ferreira RA de Zea Bermudez V Julián-López B Escribano P 《Chemical Society reviews》2011,40(2):536-549
Research on organic-inorganic hybrid materials containing trivalent lanthanide ions (Ln(3+)) is a very active field that has rapidly shifted in the last couple of years to the development of eco-friendly, versatile and multifunctional systems, stimulated by the challenging requirements of technological applications spanning domains as diverse as optics, environment, energy, and biomedicine. This tutorial review offers a general overview of the myriad of advanced Ln(3+)-based organic-inorganic hybrid materials recently synthesised, which may be viewed as a major innovation in areas of phosphors, lighting, integrated optics and optical telecommunications, solar cells, and biomedicine. 相似文献
78.
Electron paramagnetic resonance (EPR) analysis of neutral and acidic solutions of 2,5-dimethyl-1-phenylpyrrol (1) and meta-, para-, and ortho-bis(2,5-dimethylpyrrol-1-yl)benzenes (4-6) in the presence of Tl(III) trifluoroacetate as oxidant reveals the poor stability of their generated monomeric radical cations which dimerize through C(β)-C(β) bond formation. EPR spectra of the monomeric radical cations 4(?+) , 5(?+) , and 6(?+) coincide with that of 1(?+) , suggesting that the unpaired electron in these charged species is confined in one of the pyrrolic rings. The very twisted angles between pyrrolic and phenyl planes due to steric hindrance in the X-ray analysis of the molecular structure of 4 confirm the absence of extended conjugation in the π-system. 相似文献
79.
Francisco Juliá‐Hernández Prof. Dr. Aurelia Arcas Prof. Dr. José Vicente 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(25):7780-7786
The complex [Pd(O,N,C‐L)(OAc)], in which L is a monoanionic pincer ligand derived from 2,6‐diacetylpyridine, reacts with 2‐iodobenzoic acid at room temperature to afford the very stable pair of PdIV complexes (OC‐6‐54)‐ and (OC‐6‐26)‐[Pd(O,N,C‐L)(O,C‐C6H4CO2‐2)I] (1.5:1 molar ratio, at ?55 °C). These complexes and the PdII species [Pd(O,N,C‐L)(OX)] and [Pd(O,N,C‐L′)(NCMe)]ClO4, (X=MeC(O) or ClO3, L′=another monoanionic pincer ligand derived from 2,6‐diacetylpyridine), are precatalysts for the arylation of CH2?CHR (R?CO2Me, CO2Et, Ph) using IC6H4CO2H‐2 and AgClO4. These catalytic reactions have been studied and a tentative mechanism is proposed. The presence of two PdIV complexes was detected by ESI(+)‐MS during the catalytic process. All the data obtained strongly support a PdII/PdIV catalytic cycle. 相似文献
80.
Julián Bergueiro Dr. Javier Montenegro Prof. Dr. Carlos Saá Prof. Dr. Susana López 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(44):14100-14107
An expeditious, highly efficient approach to 11‐cis‐retinoids was achieved by semihydrogenation of a readily available 11‐yne precursor through a hydrosilylation–protodesilylation protocol. The complete chemo‐, regio‐, and syn‐stereoselectivity of the method also allowed direct access to 11‐ and 12‐monodeutero‐, and 11,12‐dideutero‐11‐cis‐retinoids. The analogous trans series was not accessible by this route, and was synthesized by means of Hiyama coupling. 相似文献