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51.
Sylvain Achelle Samia Kahlal Jean-Yves Saillard Nolwenn Cabon Bertrand Caro Françoise Robin-le Guen 《Tetrahedron》2014
Thirteen novel dipolar and V-shaped chromophores with pyranylidene electron-donating part, diazine electron-withdrawing part and various π-linkers were synthesized. The extent of intramolecular charge transfer, structure-property relationships and optical properties were further investigated by UV/Vis absorption, electrochemistry, and DFT calculations. 相似文献
52.
Karla G. Gutiérrez-Cuevas Rosa Julia Rodríguez-González Bertrand Donnio Damaso Navarro-Rodríguez 《Liquid crystals》2013,40(4):534-545
In this article, we report on the synthesis and thermotropic behaviour of methacrylic polymers containing 4′-(4-alkyloxyphenyl)azobenzene mesogens attached to the backbone through n-alkyloxy spacers of 6 or 10 methylene groups. Polymerisations were carried out via free radicals using azobisisobutyronitrile (AIBN) as initiator. Chemical structures of polymers and their precursors were characterised by 1H NMR spectroscopy. Thermogravimetric analysis showed that azopolymers are thermally stable up to temperatures around 300°C. The thermotropic liquid-crystalline (LC) behaviour was studied by differential scanning calorimetry (DSC), polarized optical microscopy (POM) and X-ray diffraction (XRD). Results indicate that all synthesised mesogens, monomers and polymers developed two or more orthogonal LC phases in wide temperature ranges. Mesogens and monomers developed nematic and smectic phases, whereas polymers exhibited only smectic phase. In polymers, the arrangement of mesogens depends on the relative length of the spacer and the terminal flexible chain; two distinct structural models were proposed based on chemical interactions and steric constrains. The trans–cis photoisomerisation of monomers and polymers in solution was also studied. High cis-isomer contents (>80%) were reached in relative short irradiation times despite the steric constrains imposed by the polymer backbone. 相似文献
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Ly Dieu Ha Poul Erik Hansen Fritz Duus Hung Dinh Pham Lien‐Hoa D. Nguyen 《Magnetic resonance in chemistry : MRC》2012,50(3):242-245
Four new prenylated depsidones, oliveridepsidones A–D, were isolated from the bark of Garcinia oliveri collected in Vietnam. Their structures were elucidated using mainly NMR techniques (1H and 13C NMR, HMQC, HMBC and NOE experiments). Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
56.
Camille Piovesan Anne-Laurence Dupont Isabelle Fabre-Francke Odile Fichet Bertrand Lavédrine Hervé Chéradame 《Cellulose (London, England)》2014,21(1):705-715
Two di-alkoxysilanes, with (AMDES, aminopropylmethyldiethoxysilane) or without (DMDES, dimethyldiethoxysilane) an amine function, and a tri-alkoxy aminosilane (APTES, aminopropyltriethoxysilane) as well as their mixtures were introduced in paper as fiber strengthening agents. The polymerization and copolymerization of these polysiloxanes in the paper were investigated. In all the cases where APTES was present, the formation of networks was established by measuring the soluble fraction amount extracted from the treated papers. A slight decrease of the opacity of the paper sheets when AMDES was part of the treatment was noted. The presence of APTES reduced this opacity loss. The study of the physicochemical properties of the treated paper (mechanical strength and alkalinity) demonstrated that, besides the required deacidification feature, the different treatments allowed an efficient strengthening of the cellulose fibers to various extents. Contact angle measurements indicated a decrease of the hydrophilic character of papers treated with the mixture APTES/AMDES and the occurrence of a hydrophobic character of the papers treated with APTES alone. These results were consistently obtained for both spray and immersion treatment processes. 相似文献
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Dr. Benoît Bertrand Dr. Candice Botuha Jérémy Forté Dr. Héloïse Dossmann Dr. Michèle Salmain 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(56):12846-12861
The two independent and coordination sites of a newly synthesized bis[2-(hydroxyphenyl)-1,2,4-triazole] platform have been exploited to prepare four monometallic neutral ()PtII complexes carrying DMSO, pyridine, triphenylphosphine, or N-heterocyclic carbene as the fourth ligand. Then, the second coordination site was used to introduce an IR-active rhenium tricarbonyl entity, affording the four corresponding heterobimetallic neutral PtII/ReI complexes, as well as a cationic PtII/ReI derivative. X-ray crystallographic studies showed that distortion of the organic platform occurred to accommodate the coordination geometry of both metal centers. No ligand exchange or transchelation occurred upon incubation of the PtII complexes in aqueous environment or in the presence of FeIII, respectively. The antiproliferative activity of the ligand and complexes was first screened on the triple-negative breast cancer cell line MDA-MB-231. Then, the IC50 values of the most active candidates were determined on a wider panel of human cancer cells (MDA-MB-231, MCF-7, and A2780), as well as on a nontumorigenic cell line (MCF-10A). Low micromolar activities were reached for the complexes carrying a DMSO ligand, making them the first examples of highly active, but hydrolytically stable, PtII complexes. Finally, the characteristic mid-IR signature of the {Re(CO)3} fragment in the Pt/Re heterobimetallic complexes was used to quantify their uptake in breast cancer cells. 相似文献
59.
J. P. Majoral G. Bertrand A. Baceiredo M. Mulliez R. Schmutzler 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-3):221-224
Abstract First evidence for a Curtius type rearrangement involving a pentacoordinated atom and charged species are described 相似文献
60.
The synthesis of some new functionalized quinolyl derivatives relies on the 1,3‐dipolar cycloaddition of an azomethine ylide, generated from sarcosine and paraformaldehyde, to quinolyl α,β‐unsaturated esters, followed by oxidation of the pyrrolidinyl moiety to pyrrole with activated MnO2. 相似文献