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排序方式: 共有518条查询结果,搜索用时 31 毫秒
511.
Palaprat G Marty JD Routaboul C Lattes A Mingotaud AF Mauzac M 《The journal of physical chemistry. A》2006,110(47):12887-12890
A hydrogen-bonded complex between an aromatic acid and an enantiopure chiral amine has been dissolved in a nematic solvent, giving rise to a cholesteric medium. Fourier transform infrared (FT-IR) experiments have been performed at various temperatures on both sides of the cholesteric-isotropic transition. Liquid crystalline order provides significant enhancement to the strength of interaction, inducing a discontinuous jump in concentration of the complex at the cholesteric-isotropic transition. 相似文献
512.
We study a type of one-dimensional wave equation on the plane with non-linear random forcing. We are interested in the almost sure behaviour of the normalized increments of the solution process associated to this type of wave equation. Also we study the behaviour of the normalized increments of some other stochastic integral equation. 相似文献
513.
近年来,负载型金催化剂被视为多相催化工业化进程中的机遇和挑战,因而广受研究.载体的选取可以有效调控纳米金催化剂的化学结构及催化活性.针对载体本身对反应是否具有活性,可将其分为活性载体与惰性载体.活性载体主要为具有还原性的金属氧化物;而惰性载体,诸如碳基材料、氧化硅、氧化铝等,多为反应条件下不具备还原性或不可进行还原处理... 相似文献
514.
Mohamed Amine Berkal Quentin Palas Estelle Ricard Christine Lartigau-Dagron Luisa Ronga Jean-Jacques Toulmé Corinne Parat Corinne Nardin 《Macromolecular bioscience》2023,23(8):2200508
N-phosphonomethyle-glycine (glyphosate) is the most widely used pesticide worldwide due to its effectiveness in killing weeds at a moderate cost, bringing significant economic benefits. However, owing to its massive use, glyphosate and its residues contaminate surface waters. On site, fast monitoring of contamination is therefore urgently needed to alert local authorities and raise population awareness. Here the hindrance of the activity of two enzymes, the exonuclease I (Exo I) and the T5 exonuclease (T5 Exo) by glyphosate, is reported. These two enzymes digest oligonucleotides into shorter sequences, down to single nucleotides. The presence of glyphosate in the reaction medium hampers the activity of both enzymes, slowing down enzymatic digestion. It is shown by fluorescence spectroscopy that the inhibition of ExoI enzymatic activity is specific to glyphosate, paving the way for the development of a biosensor to detect this pollutant in drinking water at suitable detection limits, i.e., 0.6 nm . 相似文献
515.
Corinne Coutant Dr. Paul De Bonfils Dr. Pierrick Nun Dr. Vincent Coeffard 《Chemical record (New York, N.Y.)》2023,23(7):e202300042
Over the past decades, the advent of asymmetric organocatalysis has changed the way chemists think about creating or breaking chemical bonds, enabling new enantioselective strategies for functionalized molecules. The success of asymmetric organocatalysis is notably based on the existence of various activation modes, leading to countless transformations, and on the vast array of available chiral organic catalysts. Breakthroughs in this area have also been driven by selective functionalization of compounds with multiple activation sites such as cyclohexanone-derived dienones. These platforms can undergo diverse transformations such as Michael addition, Friedel-Crafts alkylation or Diels-Alder cycloaddition that offer new opportunities for reaching natural products and biologically relevant compounds. Amongst cyclohexanone-derived dienones, the 2,5-cyclohexadienone motif has received a great deal of attention due to its reactivity pattern and recently, (cross)-conjugated cyclohexanone-derived substrates have also been considered. In this review, we discuss the intermolecular functionalization of (cross)-conjugated cyclohexanone-derived compounds employing asymmetric organocatalysis. 相似文献
516.
517.
Carmen Antuña-Hörlein Dr. Fule Wu Dr. Christophe Deraedt Corinne Bouillet Dr. Jean-Pierre Djukic 《欧洲无机化学杂志》2023,26(6):e202200563
The reactivity of the 2-phenylpyridine-derived [Cp*CoI(phpy-κC,N)] metallacycle towards Et3SiH and hydrides was evaluated. The treatment of the same Co(III) complex with Na[BHEt3] resulted in its decomposition into cobalt nanoparticles. The hydride-promoted decomposition of the metallacycle involves the transient formation of an elusive hydrido-cobalt(III) intermediate, the traces of which were detected by 1H NMR spectroscopy at sub-ambient temperature. The Co nanoparticles produced from a 5 mol% and 10 mol% load of cobaltacycle and Na[BHEt3] respectively contain Co(0) that is responsible for the hydrosilylation by Et3SiH of arylketones into silylalkyl ethers. To minimize the residual side reduction of carbonyls by Na[BHEt3], a mixture of 5 mol% of the latter with 5 mol% of BEt3 was found to produce optimal hydrosilylation yields at 40 °C in 2 h. Under similar conditions, several arylnitriles were mono-hydrosilylated into N-silyl-imines in yields ranging from 68 to 100 %. 相似文献
518.