Time filter

Source Type

Caneque T.,CNRS Natural Product Chemistry Institute | Truscott F.M.,CNRS Natural Product Chemistry Institute | Rodriguez R.,CNRS Natural Product Chemistry Institute | Maestri G.,CNRS Natural Product Chemistry Institute | And 3 more authors.
Chemical Society Reviews | Year: 2014

This Tutorial Review summarizes recent examples of electrophilic activation of allenes with particular focus on analogies and differences between Lewis and Brønsted acid activation of these versatile substrates. The aim of this article is to present a general overview of the possibilities offered to chemists using complementary modes of catalysis and to emphasize advantages and limitations of each approach, thereby providing a means to expand the scope of this powerful synthetic methodology. This journal is © the Partner Organisations 2014.

Derat E.,CNRS Paris Institute of Molecular Chemistry | Maestri G.,CNRS Natural Product Chemistry Institute
Wiley Interdisciplinary Reviews: Computational Molecular Science | Year: 2013

Palladium catalyzed cross-coupling reactions are one of the most widely used class of transformation as shown by the Nobel prize awarded in 2010 to Heck, Negishi, and Suzuki. Computational chemistry has a long-standing partnership with organometallics catalysis, especially with palladium. But even in a largely explored field, novelties can emerge from interplay between experiments and theory. Recent advances grounded on computational chemistry have shown that cooperative effect can explain reactivities; that despite the large number of well-known Pd(0)/Pd(II) catalytic cycle, Pd(IV) is also a realistic intermediate in some cases; that noncovalent interactions can regulate selectivities. So, despite its wide use and recognition, palladium complexes are still full of surprises! © 2013 John Wiley & Sons, Ltd.

Muller A.,Bielefeld University | Gouzerh P.,CNRS Paris Institute of Molecular Chemistry
Chemical Society Reviews | Year: 2012

Following Nature's lessons, today chemists can cross the boundary of the small molecule world to construct multifunctional and highly complex molecular nano-objects up to protein size and even cell-like nanosystems showing responsive sensing. Impressive examples emerge from studies of the solutions of some oxoanions of the early transition metals especially under reducing conditions which enable the controlled linking of metal-oxide building blocks. The latter are available from constitutional dynamic libraries, thus providing the option to generate multifunctional unique nanoscale molecular systems with exquisite architectures, which even opens the way towards adaptive and evolutive (Darwinian) chemistry. The present review presents the first comprehensive report of current knowledge (including synthesis aspects not discussed before) regarding the related giant metal-oxide clusters mainly of the type {Mo 57M′6} (M′ = FeIII, VIV) (torus structure), {M72M′30} (M = Mo, M′ = VIV, CrIII, FeIII, MoV), {M 72Mo60} (M = Mo, W) (Keplerates), {Mo154}, {Mo176}, {Mo248} ("big wheels"), and {Mo 368} ("blue lemon") - all having the important transferable pentagonal {(M)M5} groups in common. These discoveries expanded the frontiers of inorganic chemistry to the mesoscopic world, while there is probably no collection of discrete inorganic compounds which offers such a versatile chemistry and the option to study new phenomena of interdisciplinary interest. The variety of different properties of the sphere- and wheel-type metal-oxide-based clusters can directly be related to their unique architectures: The spherical Keplerate-type capsules having 20 crown-ether-type pores and tunable internal functionalities allow the investigation of confined matter as well as that of sphere-surface-supramolecular and encapsulation chemistry - including related new aspects of the biologically important hydrophobic effects - but also of nanoscale ion transport and separation. The wheel-type molybdenum-oxide clusters exhibiting complex landscapes do not only have well-defined reaction sites but also show unprecedented adaptability regarding the integration of various kinds of matter. Applications in different fields, e.g. in materials science and catalysis including those in small spaces, investigated by several groups, are discussed while possible directions for future work are outlined. © The Royal Society of Chemistry 2012.

Schaffer C.,Bielefeld University | Todea A.M.,Bielefeld University | Gouzerh P.,CNRS Paris Institute of Molecular Chemistry | Muller A.,Bielefeld University
Chemical Communications | Year: 2012

The addition of dinuclear {Mo 2} units to a dynamic library containing molybdates results in the spontaneous self-assembly of a giant spherical metal-oxide species of the type {(Mo)Mo 5} 12{Mo 2} 30 while the required pentagonal {(Mo)Mo 5} building blocks are "immediately" formed.

Curran D.P.,University of Pittsburgh | Solovyev A.,University of Pittsburgh | Makhlouf Brahmi M.,CNRS Paris Institute of Molecular Chemistry | Fensterbank L.,CNRS Paris Institute of Molecular Chemistry | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2011

Boranes are widely used Lewis acids and N-heterocyclic carbenes (NHCs) are popular Lewis bases, so it is remarkable how little was known about their derived complexes until recently. NHC-boranes are typically readily accessible and many are so stable that they can be treated like organic compounds rather than complexes. They do not exhibit "borane chemistry", but instead are proving to have a rich chemistry of their own as reactants, as reagents, as initiators, and as catalysts. They have significant potential for use in organic synthesis and in polymer chemistry. They can be used to easily make unusual complexes with a broad spectrum of functional groups not usually seen in organoboron chemistry. Many of their reactions occur through new classes of reactive intermediates including borenium cations, boryl radicals, and even boryl anions. This Review provides comprehensive coverage of the synthesis, characterization, and reactions of NHC-boranes. Forget everything you know about boron chemistry ... NHC-boranes (see picture) are different. Functionalities that are not usually present in organoboron compounds can be easily introduced. New classes of rare boron-based reactive intermediates (cations, radicals, and anions) have emerged. And NHC-boranes are promising as reagents and catalysts in organic synthesis and as co-initiators in radical polymerization. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Queffelec C.,French National Center for Scientific Research | Petit M.,French National Center for Scientific Research | Petit M.,CNRS Paris Institute of Molecular Chemistry | Janvier P.,French National Center for Scientific Research | And 2 more authors.
Chemical Reviews | Year: 2012

The basic work of researchers on methods for surface modification including metals and metal oxide coatings, and modification of metal nanoparticles are reviewed. The Michaelis-Arbuzov reaction, also known as the Arbuzov reaction, is one of the most versatile reactions for the formation of P-C bonds. The reaction consists of a triester phosphite with an alkyl halide, resulting in the conversion of P(III) to a pentavalent phosphorus species. Hirao et al. reported the first palladium catalyzed cross-coupling of alkyl halides with dialkyl phosphite. Another attractive route to organophosphonates reported by Tanaka and co-researchers consists of the addition of HPO3R2 to alkenes, and terminal alkynes using either palladium or rhodium-based catalysts. This atom-economic process was found to be versatile, efficient, and clean. Finally, while the gold standard for grafting photoactive or electroactive molecules on semiconductors was the use of CO2H anchors, there is now a rapidly growing interest in using PO3H2 functions.

Denes F.,University of Nantes | Perez-Luna A.,CNRS Paris Institute of Molecular Chemistry | Chemla F.,CNRS Paris Institute of Molecular Chemistry
Chemical Reviews | Year: 2010

A study was conducted to demonstrate the addition of metal enolate derivatives to unactivated carbon-carbon multiple bonds. The study focused on the carbometalation of alkenes, alkynes, arenes, and related unsaturated systems involving stabilized anions, such as enolates, malonates, and related stabilized nucleophiles. The investigations focused mainly on the substrates where the unsaturation partner was not activated by an electron-withdrawing group. It was demonstrated that nucleophilic addition onto unactivated C-C multiple bonds required the activation through complexation with a metal salt. The reaction was conducted in intramolecular or intermolecular manner yielding building blocks with high regio- or diastereoselectivity. It was also observed that complexation with palladium(II) salts activated alkenes efficiently toward additions of nucleophiles, including stabilized metal enolates and silyl enol ethers.

Rieger J.,CNRS Paris Institute of Molecular Chemistry
Macromolecular Rapid Communications | Year: 2015

This article presents the recent developments of radical dispersion polymerizaton controlled by reversible addition fragmentation chain transfer (RAFT) for the production of block copolymer particles of various morphologies, such as core-shell spheres, worms, or vesicles. It is not meant to be an exhaustive review but it rather provides guidelines for non-specialists. The article is subdivided into eight sections. After a general introduction, the mechanism of polymerization-induced self-assembly (PISA) through RAFT-mediated dispersion polymerization is presented and the different parameters that control the morphology produced are discussed. The next two sections are devoted to the choice of the monomer/solvent pair and the macroRAFT agent. Afterwards, post-polymerization morphological order-to-order transitions (i.e. morphological transitions triggered by extrinsic stimuli) or order-to-disorder transitions (i.e. disassembly of chains) are discussed. Assemblies based on more complex polymer architectures, such as triblock copolymers, are presented next, and finally the possibility to stabilize these structures by crosslinking is reported. The manuscript ends with a short conclusion and an outlook. RAFT dispersion polymerization is a versatile and efficient tool to prepare core-shell particles of various morphologies by polymerization-induced self-assembly. This article reviews recent developments in this field, critically comments on them, and gives an outlook on further expected developments. It provides guidelines for non-experts by highlighting important aspects that must carefully be considered when planning the preparation of core-shell nanoobjects using this approach. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Train C.,CNRS French National High Magnetic Field Laboratory | Train C.,Joseph Fourier University | Gruselle M.,CNRS Paris Institute of Molecular Chemistry | Verdaguer M.,CNRS Paris Institute of Molecular Chemistry
Chemical Society Reviews | Year: 2011

In this critical review, it is shown how the introduction of chirality and the control of the absolute configurations of chiral elements in molecular magnets allow obtaining enantiopure chiral magnets (ECM), an archetype of multifunctional materials. This task has been recognised as a major challenge for both chemists and physicists of molecular magnetism. To reach this goal, the former have combined the rational approaches towards molecular-based magnets and of enantiopure metal-organic frameworks. They have used enantiopure stable radicals, ligands from the chiral pool, enantiopure coligands associated with achiral connectors or enantioselective self-assembly to successfully reach their synthetic targets. They were motivated by the will to obtain suitable systems for the experimental demonstration of the influence of enantiomeric purity on the physico-chemical properties. This influence can be found in the magnetic properties themselves but, most interestingly, in the coexistence and interaction between the properties arising from controlled non-centrosymmetry. Thus the combination of natural circular dichroism, second harmonic generation or ferroelectricity with long-range magnetic ordering can give birth to new properties like magneto-chiral dichroism, magnetisation induced second harmonic generation or multiferroicity. The two former synergetic effects have already been demonstrated in enantiopure chiral magnets. The third one remains a challenging target that can be reached by adapting strategies developed towards enantiopure molecular ferroelectrics (119 references). © The Royal Society of Chemistry 2011.

Aubert C.,CNRS Paris Institute of Molecular Chemistry | Fensterbank L.,CNRS Paris Institute of Molecular Chemistry | Garcia P.,CNRS Paris Institute of Molecular Chemistry | Malacria M.,CNRS Paris Institute of Molecular Chemistry | Simonneau A.,CNRS Paris Institute of Molecular Chemistry
Chemical Reviews | Year: 2011

Advances on the transition metal catalyzed cycloisomerizations of 1,n-allenynes and 1,n-allenenes are summarized. Malacria reported the first transition metal-mediated isomerization of allenynes and Brummond proposed the formation of a rhodacyclopentene intermediate, which after β-H and reductive elimination gives the cross-conjugated triene. Hydroxylated 1,5 allenynes were explored by Malacria and Fensterbank in the context of gold and platinum catalysis. In 2008, Akita reported the gold(III)-catalyzed cycloisomerizations of 1-allenyl-1-ethynyl acetates into 4-methylene-2- cyclopentenones. Mascarenas reported the platinum and NHC-gold complexes catalyzed reaction of allenediene to give diastereoselectively 1,4-cycloheptadiene derivatives. The groups of Toste and Iwasawa independently reported respectively the gold- and platinum-catalyzed cyclization of vinylallenes.

Loading CNRS Paris Institute of Molecular Chemistry collaborators
Loading CNRS Paris Institute of Molecular Chemistry collaborators