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Confinement dans les nanotubes
(18) Production(s) de l'année 2019
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Prospect of Thiazole‐based γ‐Peptide Foldamers in Enamine Catalysis: Exploration of the Nitro‐Michael Addition
Auteur(s): Aguesseau‐kondrotas Julie, Simon Matthieu, Legrand Baptiste, Bantignies J.-L., Kang Young Kee, Dumitrescu Dan, Van der lee Arie, Campagne Jean‐marc, de Figueiredo Renata Marcia, Maillard Ludovic
(Article) Publié:
Chemistry - A European Journal, vol. 25 p.7396-7401 (2019)
Ref HAL: hal-02167326_v1
DOI: 10.1002/chem.201901221
WoS: 000469274700022
Exporter : BibTex | endNote
6 Citations
Résumé: 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.
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Comprehensive model of the optical spectra of carbon nanotubes on a substrate by polarized microscopy
Auteur(s): Monniello L., Tran H.-N., Vialla R., Prevot G., Tahir S., Michel T., Jourdain V.
(Article) Publié:
Physical Review B, vol. 99 p.115431 (2019)
Texte intégral en Openaccess :
Ref HAL: hal-02134571_v1
DOI: 10.1103/PhysRevB.99.115431
WoS: 000462895200004
Exporter : BibTex | endNote
Résumé: Polarized optical microscopy and spectroscopy are progressively becoming key methods for the high-throughput characterization of individual carbon nanotubes (CNTs) and other one-dimensional nanostructures, on substrate and in devices. The optical response of CNTs on substrate in cross polarization experiments is usually limited by the polarization conservation of the optical elements in the experimental setup. We developed a theoretical model taking into account the depolarization by the setup and the optical response of the substrate. We show that proper modelization of the experimental data requires to take into account both noncoherent and coherent light depolarization by the optical elements. We also show how the nanotube signal can be decoupled from the complex reflection factor of the antireflection substrate, which is commonly used to enhance the optical contrast. Finally, we describe an experimental protocol to extract the depolarization parameters and the complex nanotube susceptibility, and how it can improve the chirality assignment of individual carbon nanotubes in complex cases.
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One-pot preparation of iron/alumina catalyst for the efficient growth of vertically-aligned carbon nanotube forests
Auteur(s): Roussey Arthur, Venier Nicolas, Fneich Hussein, Giardella Lucas, Pinaud Thomas, Tahir S., Pelaez-Fernandez Mario, Arenal Raul, Mehdi Ahmad, Jourdain V.
(Article) Publié:
Materials Science And Engineering: B, vol. 245 p.37-46 (2019)
Texte intégral en Openaccess :
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Organic–inorganic nanohybrid materials: Self-assembling and properties
Auteur(s): Bantignies J.-L., Le Parc R.
Conférence invité: Nanomaterials Applications Conference (NANOAPP19) (Ljubljana, SI, 2019-06-03)
Résumé: Over the past two decades significant efforts have been directed towards the elucidation of synthesis/structure/function correlations to guide the development of synthetic strategies for controlling the composition, size and shape of nanomaterials. In this context, organic–inorganic nanohybrids incorporating bridged silsesquioxanes have been of particular interest, due to their versatility and the structural control that can be achieved through independent modulation of the properties of the organic bridge and inorganic moieties. Such strategies have also been applied to the production of thin films on a variety of substrates, driven by the continuous need to develop new and enhanced materials with nanostructures engineered over multiple length scales for applications in electronics, optics, sensing, ferromagnetic, shape-selective membranes, etc.
In this talk, I will first present a fundamental study of the nanostructuring mechanisms of model hybrid silica. Our experimental investigation was performed using an in operando approach (vibrational spectroscopies under pressure, light diffusion, microscopy) coupled with DFT calculations. Parameters controlling the evolution of the system during sol−gel processing: supramolecular interactions, hydrolysis, polycondensation, and nucleation and growth of the hybrid solid in solution were investigated. The relation between structural properties and applications will be then highlighted1-4.
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