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151.
Despite being relevant in many natural and industrial processes, suspensions of nonspherical particles have been largely underinvestigated compared with the extensive analyses made on the gravity-driven motions of spherical particles. One of the main reasons for this disparity is the difficulty of accurately correcting the short-range hydrodynamic forces and torques acting on complex particles. These effects, also known as lubrication, are essential to the suspension of the particles and are usually poorly captured by direct numerical simulation of particle-laden flows. In this article, we propose a partitioned volume penalization-discrete element method solver, which estimates the unresolved hydrodynamic forces and torques. Corrections are made locally on the surface of the interacting particles without any assumption on the particle global geometry. Numerical validations have been made using ellipsoidal particles immersed in an incompressible Navier-Stokes flow. 相似文献
152.
Baptiste Leforestier Dr. Matthew R. Gyton Dr. Adrian B. Chaplin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(52):23706-23710
By use of a macrocyclic phosphinite pincer ligand and bulky substrate substituents, we demonstrate how the mechanical bond can be leveraged to promote the oxidative addition of an interlocked 1,3-diyne to a rhodium(I) center. The resulting rhodium(III) bis(alkynyl) product can be trapped out by reaction with carbon monoxide or intercepted through irreversible reaction with dihydrogen, resulting in selective hydrogenolysis of the C−C σ-bond. 相似文献
153.
Baptiste Abadie Damien Jardel Dr. Gianluca Pozzi Prof. Dr. Patrick Toullec Dr. Jean-Marc Vincent 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(70):16120-16127
Photocatalyzed Giese-type alkylations of C(sp3)−H bonds are very attractive reactions in the context of atom-economy in C−C bond formation. The main limitation of such reactions is that when using highly polymerizable olefin acceptors, such as unsubstituted acrylates, acrylonitrile, or methyl vinyl ketone, radical polymerization often becomes the dominant or exclusive reaction pathway. Herein, we report that the polymerization of such olefins is strongly limited or suppressed when combining the photocatalytic activity of benzophenone (BP) with a catalytic amount of Cu(OAc)2. Under mild and operationally simple conditions, the Giese adducts resulting from the C(sp3)−H functionalization of amines, alcohols, ethers, and cycloalkanes could be synthesized. Preliminary mechanistic studies have revealed that the reaction does not proceed through a radical chain, but through a dual BP/Cu photocatalytic process, in which both CuII and low-valent CuI/0 species, generated in situ by reduction by the BP ketyl radical, may react with α-keto or α-cyano intermediate radicals, thus preventing polymerization. 相似文献
154.
Julie Aguesseau-Kondrotas Dr. Matthieu Simon Dr. Baptiste Legrand Prof. Jean-Louis Bantigniès Prof. Young Kee Kang Dr. Dan Dumitrescu Dr. Arie Van der Lee Prof. Jean-Marc Campagne Dr. Renata Marcia de Figueiredo Dr. Ludovic T. Maillard 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(30):7396-7401
As three-dimensional folding is prerequisite to biopolymer activity, complex functions may also be achieved through foldamer science. Because of the diversity of sizes, shapes and folding available with synthetic monomers, foldamer frameworks enable a numerous opportunities for designing new generations of catalysts. We herein demonstrate that heterocyclic γ-peptide scaffolds represent a versatile platform for enamine catalysis. One central feature was to determine how the catalytic activity and the transfer of chiral information might be under the control of the conformational behaviours of the oligomer. 相似文献
155.
Michel Gaillard Sanjit Das Mahamadou Djibo Delphine Raviglione Christian Roumestand Baptiste Legrand Nicolas Inguimbert 《Tetrahedron letters》2018,59(41):3713-3718
Lipocyclopeptides isolated from marine sources hold great promise as new lead for therapeutics. Here, we propose the first attempt towards the total synthesis of Trichormamide A. This synthesis will help to confirm the proposed structure of the cyclic lipopeptide. 相似文献
156.
A New,Simple and Versatile Strategy for the Synthesis of Short Segments of Zigzag‐Type Carbon Nanotubes 下载免费PDF全文
Dr. Etienne André Dr. Baptiste Boutonnet Pauline Charles Dr. Cyril Martini Dr. Juan‐Manuel Aguiar‐Hualde Dr. Sylvain Latil Vincent Guérineau Karim Hammad Dr. Priyanka Ray Dr. Régis Guillot Dr. Vincent Huc 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(9):3105-3114
Short segments of zigzag single‐walled carbon nanotubes (SWCNTs) were obtained from a calixarene scaffold by using a completely new, simple and expedited strategy that allowed fine‐tuning of their diameters. This new approach also allows for functionalised short segments of zigzag SWCNTs to be obtained; a prerequisite towards their lengthening. These new SWCNT short segments/calixarene composites show interesting behaviour in solution. DFT analysis of these new compounds also suggests interesting photophysical behaviour. Along with the synthesis of various SWCNTs segments, this approach also constitutes a powerful tool for the construction of new, radially oriented π systems. 相似文献
157.
158.
Baptiste Picard Boris Gouilleux Dr. Thomas Lebleu Dr. Jacques Maddaluno Prof. Isabelle Chataigner Dr. Maël Penhoat Prof. François-Xavier Felpin Dr. Patrick Giraudeau Dr. Julien Legros 《Angewandte Chemie (International ed. in English)》2017,56(26):7568-7572
The fast and effective neutralization of the mustard-gas simulant 2-chloroethyl ethyl sulfide (CEES) using a simple and portable continuous flow device is reported. Neutralization takes place through a fully selective sulfoxidation by a stable source of hydrogen peroxide (alcoholic solution of urea–H2O2 adduct/MeSO3H freshly prepared). The reaction progress can be monitored with an in-line benchtop NMR spectrometer, allowing a real-time adjustment of reaction conditions. Inherent features of millireactors, that is, perfect control of mixing, heat and reaction time, allowed the neutralization of 25 g of pure CEES within 46 minutes in a 21.5 mL millireactor (tR=3.9 minutes). This device, which relies on affordable and nontoxic reagents, fits into a suitcase, and can be deployed by police/military forces directly on the attack site. 相似文献
159.
Pd‐Catalyzed Decarboxylative Cross‐Coupling of 2‐Carboxyazine N‐Oxides with Various (Hetero)aryl Halides 下载免费PDF全文
Jean‐Baptiste Rouchet Dr. Cédric Schneider Dr. Cédric Spitz Johan Lefèvre Prof. George Dupas Dr. Corinne Fruit Prof. Christophe Hoarau 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(13):3610-3615
Decarboxylative cross‐coupling reactions of substituted 2‐carboxyazine N‐oxides, with a variety of (hetero)aryl halides, by bimetallic Pd0/CuI and Pd0/AgI catalysis are reported. Two possible pathways, a conventional bimetallic‐catalyzed decarboxylative arylation, as well as a protodecarboxylative/direct C?H arylation sequence have been considered. These methods provide the first general decarboxylative arylation methodology for the 2‐carboxyazine series. 相似文献
160.
Antoine Reigue Baptiste Augui Pablo G. Etchegoin Eric C. Le Ru 《Journal of Raman spectroscopy : JRS》2013,44(4):573-581
The aim of this work is to illustrate the power of recently developed methods for measuring resonance Raman scattering (RRS) spectra of efficient fluorophores (using a standard continuous wave excitation and a charge‐coupled device (CCD)‐based Raman spectrometer), by applying them to a detailed study of a specific fluorophore: Nile Blue A. A combination of methods are used to measure the RRS properties of Nile Blue A in water (quantum yield (QY) of 4%) and ethanol (QY of 22%) at excitation wavelengths between 514 and 647 nm, thus covering both pre‐resonance and RRS conditions. Standard Raman measurements are used in situations where the fluorescence background is small enough to clearly observe the Raman peaks, while the recently introduced polarization‐difference RRS and continuously shifted Raman scattering are used closer to (or at) resonance. We show that these relatively straightforward methods allow us to determine the Raman cross‐sections of the most intense Raman peaks and provide an accurate measurement of their line‐width; even for broadenings as low as ∼ 4 cm − 1. Moreover, the obtained Raman excitation profiles agree well with those derived from the optical absorption by a simple optical transform model. This study demonstrates the possibility of routine RRS measurements using standard Raman spectrometers, as opposed to more complicated time‐resolved techniques. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献