CNRS Orsay Institute of Molecular Chemistry

Paris, France

CNRS Orsay Institute of Molecular Chemistry

Paris, France

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Mahy J.-P.,CNRS Orsay Institute of Molecular Chemistry | Ciesielski J.,CNRS Natural Product Chemistry Institute | Dauban P.,CNRS Natural Product Chemistry Institute
Angewandte Chemie - International Edition | Year: 2014

Catalytic C-H aminations with natural enzymes have not been reported thus far. However, when a cytochrome P450 enzyme is modified by switching from an iron(III) to an iron(II) center and by mutating amino acids that are critical for the catalytic activity of this monooxygenase, this modified enzyme catalyzes the intramolecular C-H amination of benzenesulfonyl azides. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Frem D.,CNRS Orsay Institute of Molecular Chemistry
Journal of Energetic Materials | Year: 2015

A new formula is proposed for predicting the Gurney velocity ((Formula presented.)) of pure, mixed, and aluminized high explosives at any initial density. The simple relationship uses the detonation pressure and adiabatic coefficient calculated via the BKW code using the 1,3,5-Trinitro-1,3,5-triazacyclohexane (RDX) set of parameters. For 27 explosive compositions, (Formula presented.) was estimated using both the new formula and three older ones, and the results of each were then compared to experimental values. It is found that the new relationship is more accurate than older ones for predicting the Gurney velocity of aluminized compositions. The root mean square (rms) deviation of the new formula is 0.04–0.05 km/s for all tested explosives. © 2015, Taylor & Francis Group, LLC.


Truong T.-K.-T.,CNRS Orsay Institute of Molecular Chemistry | Vo-Thanh G.,CNRS Orsay Institute of Molecular Chemistry
Tetrahedron | Year: 2010

An efficient procedure for the synthesis of functionalized chiral ammonium, imidazolium, and pyridinium-based ionic liquids derived from (IR, 2S)-ephedrine using solvent-free microwave activation has been described. Good yields were obtained in very short reaction time. These chiral ionic liquids were used as chiral reaction media for the asymmetric Michael addition, giving good yields and moderate enantioselectivities. © 2010 Elsevier Ltd.


Lancry M.,CNRS Orsay Institute of Molecular Chemistry | Regnier E.,Center Data 4 | Poumellec B.,CNRS Orsay Institute of Molecular Chemistry
Progress in Materials Science | Year: 2012

This paper will thus give an overview of methods to reduce efficiently the Rayleigh scattering loss via the fictive temperature in silica-based optical fibers. We will first recall what the concept of fictive temperature T f is and its limitations in section 2. We will see that both Raman and IR spectroscopy can be used to determine T f (Section 3). Section 4 will thus give some examples of T f profiles measured in optical fibers manufactured in different conditions. Finally, section 5 will present the main approaches to reduce Rayleigh scattering loss in silica-based fibers via a reduction of T f. © 2011 Elsevier Ltd. All rights reserved.


Beaud R.,CNRS Orsay Institute of Molecular Chemistry | Guillot R.,CNRS Orsay Institute of Molecular Chemistry | Kouklovsky C.,CNRS Orsay Institute of Molecular Chemistry | Vincent G.,CNRS Orsay Institute of Molecular Chemistry
Angewandte Chemie - International Edition | Year: 2012

IRONic electrophilic indoles! The C3-regioselective hydroarylation of N-acetyl indoles with aromatic nucleophiles mediated by FeCl3 features a rare example of the electrophilic reactivity of the indole core in a Friedel-Crafts reaction. This indole umpolung allows us straightforward access to the tetracyclic benzofuroindoline motif found in the natural product diazonamide A, which is a potent antitumor agent. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Barthes-Labrousse M.-G.,CNRS Orsay Institute of Molecular Chemistry
Journal of Adhesion | Year: 2012

Detailed investigations of the interaction of 1,2- diaminoethane with aluminium surfaces have been performed to understand the mechanisms of interphase formation in epoxy-amine/aluminium joints. In particular, it has been shown that both metal bond surface complexes (O-Al⋯N bonds) and hydrogen-bonded surface complexes (Al-OH⋯N and C xO yH z⋯N bonds) can be formed on aluminium surfaces covered with a partly contaminated (hydr)oxide film. However, surface dissolution can only be induced by mononuclear bidentate metal bond surface complexes (chelates), which result from a ligand exchange mechanism between specific hydroxyl sites (η 1- and μ 2-OH) of the surface and the amino terminations of the molecule. The formation of these chelates weakens the trans Al-O bonds and detachment of the ligand-metal complexes can occur. This mechanism is enhanced by the presence of moisture. In practical epoxy-amine/aluminium joints, the interphase can, thus, be formed by migration of these complexes in the liquid polymeric phase before curing is achieved. © 2012 Copyright Taylor and Francis Group, LLC.


Vincent G.,CNRS Orsay Institute of Molecular Chemistry | Guillot R.,CNRS Orsay Institute of Molecular Chemistry | Kouklovsky C.,CNRS Orsay Institute of Molecular Chemistry
Angewandte Chemie - International Edition | Year: 2011

In control! N-alkoxybicyclolactams derived from the ring-rearrangement metathesis of nitroso Diels-Alder cycloadducts were subjected to the successive addition of two nucleophiles to yield substituted piperidine or pyrrolidine precursors with good to excellent stereoselectivity. The relative configuration of the newly formed stereocenter can be controlled by the order of addition of the two nucleophiles. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Soncini A.,Catholic University of Leuven | Mallah T.,CNRS Orsay Institute of Molecular Chemistry | Chibotaru L.F.,Catholic University of Leuven
Journal of the American Chemical Society | Year: 2010

We theoretically investigate the charge and spin transport through a binuclear FeIIIFeIII iron complex connected to two metallic electrodes. During the transport process, the FeIIIFe III dimer undergoes a one-electron reduction (Coulomb blockade transport regime), leading to the reduced mixed-valence FeII Fe III species. For such a system, the additional electron may be fully delocalized leading to the stabilization of the highest spin ground state S = 9/2 by the double exchange mechanism, while the original FeIIIFe III has usually an S = 0 spin ground state due to the antiferromagnetic exchange coupling between the two FeIII ions. Intuitively, the spin delocalization within the mixed-valence complex may be thought to favor charge and spin transport through the molecule between the two metallic electrodes. Contrary to such an intuitive concept, we find that the increased delocalization leads in fact to a blocking of the transport, if the exchange coupling interaction within the FeIIIFeIII dimer is antiferromagnetic. This is due to the violation of the spin angular momentum conservation, where a change of half a unit of spin (δS = 1/2) is allowed between two different redox states of the molecule. The result is explained in terms of a double-exchange blockade mechanism, triggered by the interplay between spin delocalization and antiferromagnetic coupling between the magnetic cores. Consequently, ferromagnetically coupled dimers are shown not to be affected by the double-exchange blockade mechanism. The situation is evocative of the onset and removal of giant magnetoresistance in the conductance of diamagnetic layers, as a function of the relative alignment of the magnetization of two weakly antiferromagnetically coupled ferromagnetic contacts. Numerical simulations accounting for the effect of vibronic coupling show that the spin current increases as a function of spin delocalization in Class I and Class II mixed-valence dimers. The signature of vibronic coupling on sequential spin-tunneling processes through Class I and Class II mixed-valence systems is identified and discussed. © 2010 American Chemical Society.


Beaud R.,CNRS Orsay Institute of Molecular Chemistry | Guillot R.,CNRS Orsay Institute of Molecular Chemistry | Kouklovsky C.,CNRS Orsay Institute of Molecular Chemistry | Vincent G.,CNRS Orsay Institute of Molecular Chemistry
Chemistry - A European Journal | Year: 2014

A method for the direct and rare umpolung of the 3 position of indoles is reported. The activation of N-acetylindole with iron(III) chloride allows the C-H addition of aromatic and heteroaromatic substrates to the C2-C3 double bond of the indole nucleus to generate a quaternary center at C3 and leads regioselectively to 3-arylindolines. Optimization, scope (50 examples), practicability (gram scale, air atmosphere, room temperature), and mechanistic insights of this process are presented. Synthetic transformations of the indoline products into drug-like compounds are also described. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Bonnaffe D.,CNRS Orsay Institute of Molecular Chemistry
Comptes Rendus Chimie | Year: 2011

Heparan sulfate (HS) and heparin (HP) belong to the glycosaminoglycan (GAG) family, which are linear and sulfated polysaccharides. Several levels of molecular diversity allow these polymers to display one of the highest information content amongst all biopolymers and to bind and regulate, often in a specific way, the activity of numerous proteins. After analysing the structural basis of HS and HP molecular diversity, we will describe how chemists are able to exploit several of these features to produce compounds with exquisite tailor-made bioactivities and optimised pharmacological profiles, leading to promising drug candidates in preclinical or clinical studies and approved treatments.

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