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  • F. Foschi, C. Loro, R. Sala, J. Oble, L. Lo Presti, E. M. Beccalli, G. Poli, et G. Broggini, « Intramolecular Aminoazidation of Unactivated Terminal Alkenes by Palladium-Catalyzed Reactions with Hydrogen Peroxide as the Oxidant », Organic Letters, vol. 22, nᵒ 4, p. 1402-1406, févr. 2020.
    Résumé : The palladium-catalyzed aminoazidation of aminoalkenes yielding azidomethyl-substituted nitrogen-containing heterocycles was developed. The procedure requires oxidative conditions and occurs at room temperature in the presence of hydrogen peroxide and NaN3 as the azide source. These conditions provide selective exo-cyclization/azidation of the carbon–carbon double bond, furnishing a versatile approach toward five-, six-, and seven-membered heterocyclic rings.
    Mots-clés : POLE 1, ROCS.
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  • A. Generosi, M. Guaragno, Q. Zhu, A. Proust, N. T. Barrett, L. Tortech, et B. Paci, « In-Situ Energy Dispersive X-ray Reflectivity Applied to Polyoxometalate Films: An Approach to Morphology and Interface Stability Issues in Organic Photovoltaics », Symmetry, vol. 12, nᵒ 8, p. 1240, févr. 2020.
    Résumé : Organic solar cells, characterized by a symmetrical regular layered structure, are very promising systems for developing green, low cost, and flexible solar energy conversion devices. Despite the efficiencies being appealing (over 17%), the technological transfer is still limited by the low durability. Several processes, in bulk and at interface, are responsible. The quick downgrading of the performance is due to a combination of physical and chemical degradations. These phenomena induce instability and a drop of performance in working conditions. Close monitoring of these processes is mandatory to understand the degradation pathways upon device operation. Here, an unconventional approach based on Energy Dispersive X-ray Reflectivity (ED-XRR) performed in-situ is used to address the role of Wells–Dawson polyoxometalate (K6-P2W18O62, hereafter K6-P2W18) as hole transporting layer in organic photovoltaics. The results demonstrate that K6-P2W18 thin films, showing ideal bulk and interface properties and superior optical/morphological stability upon prolonged illumination, are attractive candidates for the interface of durable OPV devices.
    Mots-clés : E-POM, in-situ X-ray characterization, organic photovoltaics, POLE 2, polyoxymetalate functional materials, thin films structure and morphology, time resolved EDXR.
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  • F. Giusti, M. Casiraghi, E. Point, M. Damian, J. Rieger, C. L. Bon, A. Pozza, K. Moncoq, J. - L. Banères, et L. J. Catoire, « Structure of the agonist 12–HHT in its BLT2 receptor-bound state », Scientific Reports, vol. 10, nᵒ 1, p. 2630, févr. 2020.
    Résumé : G Protein-Coupled receptors represent the main communicating pathway for signals from the outside to the inside of most of eukaryotic cells. They define the largest family of integral membrane receptors at the surface of the cells and constitute the main target of the current drugs on the market. The low affinity leukotriene receptor BLT2 is a receptor involved in pro- and anti-inflammatory pathways and can be activated by various unsaturated fatty acid compounds. We present here the NMR structure of the agonist 12–HHT in its BLT2-bound state and a model of interaction of the ligand with the receptor based on a conformational homology modeling associated with docking simulations. Put into perspective with the data obtained with leukotriene B4, our results illuminate the ligand selectivity of BLT2 and may help define new molecules to modulate the activity of this receptor.
    Mots-clés : POLE 4, POLYMERES.
    Pièce jointe Full Text PDF 2.8 Mo (source)

  • J. Glatz, L. - M. Chamoreau, A. Flambard, J. - F. Meunier, A. Bousseksou, et R. Lescouëzec, « Thermo- and electro-switchable Cs⊂{Fe <sub>4</sub> –Fe <sub>4</sub> } cubic cage: spin-transition and electrochromism », Chemical Communications, vol. 56, nᵒ 74, p. 10950-10953, 2020.
    Résumé : The Cs⊂{Fe 4 –Fe 4 } cube is a dual redox and magnetic switch showing remarkable electrochromic properties and spin-transition in its neutral state. , A mixed valence Cs⊂{Fe 4 –Fe 4 } cyanido-cube was synthesized and structurally characterized. The molecule, which is robust in solution, shows remarkable electronic versatility. Electrochromic properties associated with nine different electronic states are observed in solution together with a thermo-induced spin-transition in the solid state.
    Mots-clés : ERMMES, POLE 2.

  • Y. T. L. Guen, T. L. Gall, P. Midoux, P. Guégan, S. Braun, et T. Montier, « Gene transfer to skeletal muscle using hydrodynamic limb vein injection: current applications, hurdles and possible optimizations », The Journal of Gene Medicine, vol. 22, nᵒ 2, p. e3150, 2020.
    Résumé : Hydrodynamic limb vein injection is an in vivo locoregional gene delivery method. It consists of administrating a large volume of solution containing nucleic acid constructs in a limb with both blood inflow and outflow temporarily blocked using a tourniquet. The fast, high pressure delivery allows the musculature of the whole limb to be reached. The skeletal muscle is a tissue of choice for a variety of gene transfer applications, including gene therapy for Duchenne muscular dystrophy or other myopathies, as well as for the production of antibodies or other proteins with broad therapeutic effects. Hydrodynamic limb vein delivery has been evaluated with success in a large range of animal models. It has also proven to be safe and well-tolerated in muscular dystrophy patients, thus supporting its translation to the clinic. However, some possible limitations may occur at different steps of the delivery process. Here, we have highlighted the interests, bottlenecks and potential improvements that could further optimize non-viral gene transfer following hydrodynamic limb vein injection.
    Mots-clés : gene transfer, hydrodynamic delivery, locoregional, non-viral gene delivery, optimizations, POLE 4, POLYMERES, skeletal muscle.
    Pièce jointe Full Text PDF 6.4 Mo (source)
    Note Note
    <p>e3150 JGM-19-0364.R1</p>

  • H. Guo, D. Hourdet, A. Marcellan, F. Stoffelbach, J. Lyskawa, L. de Smet, A. Vebr, R. Hoogenboom, et P. Woisel, « Dual Responsive Regulation of Host–Guest Complexation in Aqueous Media to Control Partial Release of the Host », Chemistry – A European Journal, vol. 26, nᵒ 6, p. 1292-1297, janv. 2020.
    Résumé : Abstract The regulation of the concentration of a wide range of small molecules is ubiquitous in biological systems because it enables them to adapt to the continuous changes in the environmental conditions. Herein, we report an aqueous synthetic system that provides an orchestrated, temperature and pH controlled regulation of the complexation between the cyclobis(paraquat-p-phenylene) host (BBox) and a 1,5-dialkyloxynaphthalene (DNP) guest attached to a well-defined dual responsive copolymer composed of N-isopropylacrylamide as thermoresponsive monomer and acrylic acid as pH-responsive monomer. Controlled, partial release of the BBox, enabling control over its concentration, is based on the tunable partial collapse of the copolymer. This colored supramolecular assembly is one of the first synthetic systems providing control over the concentration of a small molecule, providing great potential as both T and pH chromic materials and as a basis to develop more complex systems with molecular communication.
    Mots-clés : host–guest systems, molecular recognition, POLE 4, POLYMERES, polymers, supramolecular chemistry.

  • W. Hamouda, A. Pancotti, C. Lubin, L. Tortech, C. Richter, T. Mikolajick, U. Schroeder, et N. Barrett, « Physical chemistry of the TiN/Hf0.5Zr0.5O2 interface », Journal of Applied Physics, vol. 127, nᵒ 6, p. 064105, févr. 2020.
    Résumé : Ferroelectric hafnia-based thin films are promising candidates for emerging high-density embedded nonvolatile memory technologies, thanks to their compatibility with silicon technology and the possibility of 3D integration. The electrode–ferroelectric interface and the crystallization annealing temperature may play an important role in such memory cells. The top interface in a TiN/Hf0.5Zr0.5O2/TiNTiN/Hf0.5Zr0.5O2/TiN<math display="inline" overflow="scroll" altimg="eq-00001.gif"> <mrow> <mi mathvariant="normal">TiN</mi></mrow> <mo>/</mo> <msub> <mrow> <mi mathvariant="normal">Hf</mi></mrow> <mrow> <mn>0.5</mn></mrow></msub> <msub> <mrow> <mi mathvariant="normal">Zr</mi></mrow> <mrow> <mn>0.5</mn></mrow></msub> <msub> <mrow> <mi mathvariant="normal">O</mi></mrow> <mn>2</mn></msub> <mo>/</mo> <mrow> <mi mathvariant="normal">TiN</mi></mrow></math> metal–ferroelectric–metal stack annealed at different temperatures was investigated with X-ray photoelectron spectroscopy. The uniformity and continuity of the 2 nm TiN top electrode was verified by photoemission electron microscopy and conductive atomic force microscopy. Partial oxidation of the electrode at the interface is identified. Hf is reduced near the top interface due to oxygen scavenging by the top electrode. The oxygen vacancy (VOVO<math display="inline" overflow="scroll" altimg="eq-00002.gif"> <msub> <mi>V</mi> <mrow> <mi mathvariant="normal">O</mi></mrow></msub></math>) profile showed a maximum at the top interface (0.71%) and a sharp decrease into the film, giving rise to an internal field. Annealing at higher temperatures did not affect the VOVO<math display="inline" overflow="scroll" altimg="eq-00003.gif"> <msub> <mrow> <mi mathvariant="normal">V</mi></mrow> <mrow> <mrow> <mi mathvariant="normal">O</mi></mrow></mrow></msub></math> concentration at the top interface but causes the generation of additional VOVO<math display="inline" overflow="scroll" altimg="eq-00004.gif"> <msub> <mrow> <mi mathvariant="normal">V</mi></mrow> <mrow> <mrow> <mi mathvariant="normal">O</mi></mrow></mrow></msub></math> in the film, leading to a decrease of the Schottky Barrier Height for electrons. The interface chemistry and n-type film doping are believed to be at the origin of several phenomena, including wake-

    up, imprint, and fatigue. Our results give insights into the physical chemistry of the top interface with the accumulation of defective charges acting as electronic traps, causing a local imprint effect. This may explain the wake-up behavior as well and also can be a possible reason of the weaker endurance observed in these systems when increasing the annealing temperature.
    Mots-clés : E-POM, POLE 2.
    Pièce jointe Snapshot 515.9 ko (source)
    Pièce jointe Full Text PDF 2.6 Mo (source)

  • S. Han, G. Mellot, S. Pensec, J. Rieger, F. Stoffelbach, E. Nicol, O. Colombani, J. Jestin, et L. Bouteiller, « Crucial Role of the Spacer in Tuning the Length of Self-Assembled Nanorods », Macromolecules, vol. 53, nᵒ 1, p. 427-433, janv. 2020.
    Résumé : Polymeric supramolecular nanorods were prepared in toluene by self-assembly of tris(urea) stickers connected on both sides through alkyl spacers of different lengths to short polystyrene (PS) arms. Several tris(urea) initiators or chain transfer agents were synthesized straightforwardly and used to grow well-defined PS arms via atom transfer radical polymerization (ATRP) or reversible addition fragmentation chain transfer (RAFT) polymerization. Self-assembly was investigated by means of Fourier-transform infrared (FTIR) spectroscopy and light/neutron scattering. A dramatic impact of the spacer separating the tris(urea) sticker from the PS arms on the extent of self-assembly was observed in toluene as long as the degree of polymerization of the PS arms (x) was kept short (x ∼ 10). Indeed, supramolecular nanorods several hundreds of nanometers in length for a few nanometers in radius were obtained with a spacer consisting of nine atoms, whereas five times shorter nanorods were obtained for a spacer of only five atoms, and spherical particles were found in the absence of any spacer, all other parameters remaining unchanged. These results reveal the possibility to tune the length of polymer-decorated supramolecular nanorods with minimal modification of the assembling sticker and without affecting the functionality of the rods.
    Mots-clés : POLE 4, POLYMERES.
    Pièce jointe Full Text PDF 1.9 Mo (source)

  • J. A. Hawkes, J. D'Andrilli, J. N. Agar, M. P. Barrow, S. M. Berg, N. Catalán, H. Chen, R. K. Chu, R. B. Cole, T. Dittmar, R. Gavard, G. Gleixner, P. G. Hatcher, C. He, N. J. Hess, R. H. S. Hutchins, A. Ijaz, H. E. Jones, W. Kew, M. Khaksari, D. C. Palacio Lozano, J. Lv, L. R. Mazzoleni, B. E. Noriega‐Ortega, H. Osterholz, N. Radoman, C. K. Remucal, N. D. Schmitt, S. K. Schum, Q. Shi, C. Simon, G. Singer, R. L. Sleighter, A. Stubbins, M. J. Thomas, N. Tolic, S. Zhang, P. Zito, et D. C. Podgorski, « An international laboratory comparison of dissolved organic matter composition by high resolution mass spectrometry: Are we getting the same answer? », Limnology and Oceanography: Methods, vol. 18, nᵒ 6, p. 235-258, 2020.

  • X. He, M. Zhong, S. Li, X. Li, Y. Li, Z. Li, Y. Gao, F. Ding, D. Wen, Y. Lei, et Y. Zhang, « Synthesis and biological evaluation of organoselenium (NSAIDs-SeCN and SeCF3) derivatives as potential anticancer agents », European Journal of Medicinal Chemistry, vol. 208, p. 112864, déc. 2020.

  • D. Jamroz, N. Fischer-Durand, M. Palusiak, S. Wojtulewski, S. Jarzyński, M. Stępniewska, M. Salmain, et B. Rudolf, « Inverse electron-demand Diels-Alder (iEDDA) bioorthogonal conjugation of half-sandwich transition metallocarbonyl entities to a model protein », Applied Organometallic Chemistry, vol. 34, nᵒ 4, p. e5507, 2020.
    Résumé : Novel transition metallocarbonyl complexes carrying a norbornene or an oxanorbornene group were synthesized by [4 + 2] cycloaddition between the organometallic maleimide dienophiles and cyclopentadiene or furan, respectively. The oxanorbornene adduct was obtained as a mixture of endo and exo isomers as confirmed by X-ray diffraction and NMR spectroscopy. The (oxa)norbornene groups further provided convenient chemical reporters to carry out inverse electron demand Diels-Alder (iEDDA) reactions with tetrazine derivatives. Detailed kinetic studies with a model tetrazine revealed that faster rates of reaction were determined with both isomers of the oxanorbornene complex with respect to the norbornene complexes. Eventually, incorporation of metallocarbonyl entities into bovine serum albumin equipped with tetrazine handles was achieved as shown by IR spectroscopy of the protein conjugates.
    Mots-clés : bioconjugation, CHEMBIO, iEDDA, metallocarbonyl complex, norbornene, POLE 3, tetrazine.
    Note Note
    <p>doi: 10.1002/aoc.5507</p>

  • J. ‐R. Jiménez, J. Glatz, A. Benchohra, G. Gontard, L. ‐M. Chamoreau, J. ‐F. Meunier, A. Bousseksou, et R. Lescouëzec, « Electron Transfer in the Cs⊂{Mn <sub>4</sub> Fe <sub>4</sub> } Cubic Switch: A Soluble Molecular Model of the MnFe Prussian‐Blue Analogues », Angewandte Chemie International Edition, vol. 59, nᵒ 21, p. 8089-8093, mai 2020.

  • S. Kamilya, S. Ghosh, Y. Li, P. Dechambenoit, M. Rouzières, R. Lescouëzec, S. Mehta, et A. Mondal, « Two-Step Thermoinduced Metal-to-Metal Electron Transfer and ON/OFF Photoswitching in a Molecular [Fe2Co2] Square Complex », Inorganic Chemistry, vol. 59, nᵒ 17, p. 11879-11888, nov. 2020.
    Mots-clés : ERMMES, POLE 2.
    Note Note
    <p>doi: 10.1021/acs.inorgchem.0c02053</p>

  • S. H. Kyne, G. Lefèvre, C. Ollivier, M. Petit, V. - A. R. Cladera, et L. Fensterbank, « Iron and cobalt catalysis: new perspectives in synthetic radical chemistry », Chemical Society Reviews, oct. 2020.
    Résumé : This review deals with some key synthetic developments based on the use of iron or cobalt complexes to promote radical reactivity which have been devised over the last decades. We have more particularly focused on reactions for which the impact of this chemistry has yielded greener alternatives to existing processes and also on new transformations, notably hydrogen atom transfer (HAT) triggered processes, which can be promoted through the use of metallic complexes. Preliminary synthetic developments based on the use of photoactive iron and cobalt complexes are also covered.
    Mots-clés : MACO, POLE 1.
    Pièce jointe Full Text PDF 16.6 Mo (source)

  • M. Laurans, K. Trinh, K. Dalla Francesca, G. Izzet, S. Alves, E. Derat, V. Humblot, O. Pluchery, D. Vuillaume, S. Lenfant, F. Volatron, et A. Proust, « Covalent Grafting of Polyoxometalate Hybrids onto Flat Silicon/Silicon Oxide: Insights from POMs Layers on Oxides », ACS Applied Materials & Interfaces, vol. 12, nᵒ 42, p. 48109-48123, oct. 2020.
    Résumé : Immobilization of polyoxometalates (POMs) onto oxides is relevant to many applications in the fields of catalysis, energy conversion/storage, or molecular electronics. Optimization and understanding the molecule/oxide interface is crucial to rationally improve the performance of the final molecular materials. We herein describe the synthesis and covalent grafting of POM hybrids with remote carboxylic acid functions onto flat Si/SiO2 substrates. Special attention has been paid to the characterization of the molecular layer and to the description of the POM anchoring mode at the oxide interface through the use of various characterization techniques, including ellipsometry, AFM, XPS, and FTIR. Finally, electron transport properties were probed in a vertical junction configuration and energy level diagrams have been drawn and discussed in relation with the POM molecular electronic features inferred from cyclic-voltammetry, UV–visible absorption spectra, and theoretical calculations. The electronic properties of these POM-based molecular junctions are driven by the POM LUMO (d-orbitals) whatever the nature of the tether or the anchoring group.
    Mots-clés : CSOB, E-POM

    , MACO, POLE 1, POLE 2, POLE 3.
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  • E. Levernier, C. Lévêque, E. Derat, L. Fensterbank, et C. Ollivier, « Towards Visible-Light Photocatalytic Reduction of Hypercoordinated Silicon Species », Helvetica Chimica Acta, vol. 103, nᵒ 1, p. e1900238, 2020.
    Résumé : Nowadays, the quest of new radical precursors based on heteroatom complexes occupies an increasingly prominent position in contemporary research. Herein, we investigated the behavior and the limitations of hexa- or pentacoordinated organochlorosilanes and related pentacoordinated silyliums as new families of complexes for the generation of radicals under photocatalytic reductive conditions. Particularly, treatment of chlorophenylbis[N,S-pyridine-2-thiolato(−)]silicon(IV) or the related silylium derivative with the fac-Ir(ppy)3 (5 mol-%)/NEt3 (1.5 equiv.) system under blue LEDs irradiation generates a thiopyridyl radical which can participate in the formation of a carbon−sulfur bond by reaction with an allylsulfone. Computational studies supported this experimental finding, and particularly by showing that homolytic fragmentation of C−Ts bond is favored over the fragmentation of thiopyridyl radical.
    Mots-clés : allylation, chlorosilane, cyclic voltammetry, C−S bond, hypercoordinated silicon compounds, MACO, photoreduction, POLE 1, radicals, silylium.
    Pièce jointe Full Text PDF 8.3 Mo (source)

  • A. Li, Y. Li, L. - M. Chamoreau, C. Desmarets, L. Lisnard, et Y. Journaux, « A Bis-Polydentate Oxamate-Based Achiral Ligand That Can Stabilize a Macrocyclic Mixed Valence Compound or Induce a 1D Helical Chain », European Journal of Inorganic Chemistry, vol. 2020, nᵒ 34, p. 3311-3319, 2020.
    Résumé : The reaction of the N-(2-hydroxyphenyl)oxamate ligand (ohpma) has been investigated with cobalt(II) and copper(II) ions. It has led to two coordination compounds, (TMA)3[CoIII(ohpma)2CoII(MeOH)23]·10H2O·5MeOH (1) and (HNEt3)[Cu(ohpma)] (2). Both compounds have been characterized by single-crystal X-ray diffraction and magnetometry. The X-ray diffraction studies have revealed atypical structures that are not commonly observed in oxamate coordination chemistry with a macrocyclic arrangement for the mixed-valence cobalt-based complex 1, and a helical chiral chain for compound 2. In the latter, the bis-polydentate nature of the (ohpma)3– ligand with distinct tridentate and bidentate coordination sites creates a chirogenic center on the copper ion. The investigation of the magnetic properties shows for complex 1 a single-molecule magnet behavior detectable under static field, while antiferromagnetic interactions dominate the behavior of 2.
    Mots-clés : ARC, ERMMES, POLE 1, POLE 2.

  • X. Li, Q. Feng, L. Qu, T. Zhao, X. Li, T. Bai, S. Sun, S. Wu, Y. Zhang, et J. Li, « A water-soluble and incubate-free fluorescent environment-sensitive probe for ultrafast visualization of protein thiols within living cells », Analytica Chimica Acta, vol. 1126, p. 72-81, août 2020.

  • Y. Li, A. Hammoud, L. Bouteiller, et M. Raynal, « Emergence of Homochiral Benzene-1,3,5-tricarboxamide Helical Assemblies and Catalysts upon Addition of an Achiral Monomer », Journal of the American Chemical Society, vol. 142, nᵒ 12, p. 5676-5688, mars 2020.
    Résumé : Chirality amplification refers to the ability of a small chiral bias to fully control the main chain helicity of polymers and assemblies. Further implementation of functional chirally amplified helices as switchable asymmetric catalysts, chiral sensors, and circularly polarized light emitters will require a greater control of the energetics governing these chirality amplification effects. In this work, we report on the counterintuitive ability of an achiral molecule to suppress conformational defects in supramolecular helices, thus leading to the emergence of homochirality in a system containing a very small chiral bias. We focus our investigation on supramolecular helices composed of an achiral benzene-1,3,5-tricarboxamide (BTA) ligand, coordinated to copper, and an enantiopure BTA comonomer. Amplification of chirality as probed by varying the amount (sergeants and soldiers effect) or the optical purity (diluted majority-rules effect) of the enantiopure comonomer are modest in this initial system. However, both effects are hugely enhanced upon addition of a second achiral BTA monomer, leading to a perfect control of the helicity either by means of a remarkably low amount of sergeants (0.5%) or a small bias from a racemic mixture of enantiopure comonomers (10% ee). Such an enhancement in the amplification of chirality is only achieved by mixing the three components, i.e. the two achiral and the enantiopure comonomers, highlighting a synergistic effect upon coassembly of the three monomers. Investigation of the role of the achiral additive by multifarious analytical techniques supports its ability to stabilize the helical coassemblies and suppress helix reversals: i.e., conformational defects. Implementation of these helical copper precatalysts in the hydrosilylation of 1-(4-nitrophenyl)ethanone confirms that the effect of the achiral BTA additive is also operative under the conditions of the catalytic experiment. A highly enantioenriched product (90% ee) is produced by a supramolecular catalyst operating with ppm levels of chiral species.
    Mots-clés : POLE 4, POLYMERES.
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  • Y. Li, A. Benchohra, B. Xu, B. Baptiste, K. Béneut, P. Parisiades, L. Delbes, A. Soyer, K. Boukheddaden, et R. Lescouëzec, « Pressure-Induced Conversion of a Paramagnetic FeCo Complex into a Molecular Magnetic Switch with Tuneable Hysteresis », Angewandte Chemie International Edition, vol. 59, nᵒ 39, p. 17272-17276, 2020.
    Résumé : A key challenge in the design of magnetic molecular switches is to obtain bistability at room temperature. Here, we show that application of moderate pressure makes it possible to convert a paramagnetic FeIII2CoII2 square complex into a molecular switch exhibiting a full dia- to paramagnetic transition: FeIICoIII ⇔ FeIIICoII. Moreover, the complex follows a rare behavior: the higher the pressure, the broader the magnetic hysteresis. Thus, the application of an adequate pressure allows inducing a magnetic bistability at room temperature with predictable hysteresis width. The structural studies at different pressures suggest that the pressure-enhanced bistability is due to the strengthening of intermolecular interactions upon pressure increase. An original microscopic Ising-like model including pressure effects is developed to simulate this unprecedented behavior. Overall, this study shows that FeCo complexes could be very sensitive piezo switches with potential use as sensors.
    Mots-clés : ERMMES, POLE 2.

  • Z. Li, T. Bavaro, S. Tengattini, R. Bernardini, M. Mattei, F. Annunziata, R. B. Cole, C. Zheng, M. Sollogoub, L. Tamborini, M. Terreni, et Y. Zhang, « Chemoenzymatic synthesis of arabinomannan (AM) glycoconjugates as potential vaccines for tuberculosis », European Journal of Medicinal Chemistry, vol. 204, p. 112578, 2020.

  • Z. Li, C. Zheng, M. Terreni, T. Bavaro, M. Sollogoub, et Y. Zhang, « A Concise Synthesis of Oligosaccharides Derived From Lipoarabinomannan (LAM) with Glycosyl Donors Having a Nonparticipating Group at C2: A Concise Synthesis of Oligosaccharides Derived From Lipoarabinomannan (LAM) with Glycosyl Donors Having a Nonparticipating Group at C2 », European Journal of Organic Chemistry, vol. 2020, nᵒ 14, p. 2033-2044, avr. 2020.

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    Z. Li, C. Zheng, M. Terreni, L. Tanzi, M. Sollogoub, et Y. Zhang, « Novel Vaccine Candidates against Tuberculosis », Current Medicinal Chemistry, vol. 27, nᵒ 31, p. 5095-5118, sept. 2020.
    Résumé : Ranking above AIDS, Tuberculosis (TB) is the ninth leading cause of death affecting and killing many individuals every year. Drugs’ efficacy is limited by a series of problems such as Multi- Drug Resistance (MDR) and Extensively-Drug Resistance (XDR). Meanwhile, the only licensed vaccine BCG (Bacillus Calmette-Guérin) existing for over 90 years is not effective enough. Consequently, it is essential to develop novel vaccines for TB prevention and immunotherapy. This paper provides an overall review of the TB prevalence, immune system response against TB and recent progress of TB vaccine research and development. Several vaccines in clinical trials are described as well as LAM-based candidates.
    Mots-clés : GOBS, POLE 3.

  • B. Linclau, A. Ardá, N. - C. Reichardt, M. Sollogoub, L. Unione, S. P. Vincent, et J. Jiménez-Barbero, « Fluorinated carbohydrates as chemical probes for molecular recognition studies. Current status and perspectives », Chemical Society Reviews, vol. 49, nᵒ 12, p. 3863-3888, 2020.
    Résumé : Fluorinated carbohydrates have become indispensable in glycosciences. This contribution provides an overview of how fluorine introduction modifies physical and chemical properties of carbohydrates along with selected examples of its applications. , This review provides an extensive summary of the effects of carbohydrate fluorination with regard to changes in physical, chemical and biological properties with respect to regular saccharides. The specific structural, conformational, stability, reactivity and interaction features of fluorinated sugars are described, as well as their applications as probes and in chemical biology.
    Mots-clés : GOBS, POLE 3.

  • X. Liu, X. Su, C. Livache, L. - M. Chamoreau, S. Sanaur, L. Sosa-Vargas, J. - C. Ribierre, D. Kreher, E. Lhuillier, E. Lacaze, et F. Mathevet, « Investigation of charge transport properties of [1]Benzothieno[3,2-b][1]-benzothiophene single-crystals in field-effect transistor configuration », Organic Electronics, vol. 78, p. 105605, mars 2020.
    Résumé : Single-crystals of unsubstituted [1]Benzothieno[3,2-b][1]-benzothiophene (BTBT) were prepared by physical vapor transport deposition (VTP). The packing structure and morphology of the crystals were studied by X-ray diffraction (XRD), polarized optical microscopy (POM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The charge transport properties of BTBT single-crystals were also investigated via bottom contact/bottom gate (BC/BG) organic field-effect transistors (OFETs) on both SiO2 and n-octadecyltrichlorosilane (OTS) treated surfaces. A maximum hole mobility value of 0.032 cm2V−1s−1 was measured on the OTS substrate. In addition, single-crystal OFETs with ion gel top gate (TG) configuration were also investigated for low voltage operation. This work represents the first investigation of charge carrier mobility of a simple BTBT in transistor configuration and highlights the essential role of the BTBT substitution in charge transport properties.
    Mots-clés : Organic field effect transistors, POLE 4, POLYMERES, Semiconducting materials, Single crystals, Thienoacene derivative.

  • Y. Liu, J. Oble, A. Pradal, et G. Poli, « Catalytic Domino Annulations through η3-Allylpalladium Chemistry: A Never-Ending Story », European Journal of Inorganic Chemistry, vol. 2020, nᵒ 11-12, p. 942-961, 2020.
    Résumé : Annulative η3-allylpalladium chemistry has been a longstanding trending research topic since the 80's. Nowadays, this research area is still providing challenges to the catalysis community leading to the development original and brand-new transformations. Several reaction partners have been used as precursors for η3-allylpalladium species, namely allyl diacetates, allyl monoacetates, 3-acetoxy-2-trimethylsilylmethyl-1-propene (ASMP), alkylidene cyclopropanes (ACPs), vinyl cyclopropanes (VCPs), vinyl aziridines, and vinyl epoxides. This minireview is intended to show the recent developments in the field of annulative η3-allylpalladium chemistry with emphasis on new reactivity, enantioselective transformations as well as potential applications in total synthesis.
    Mots-clés : POLE 1, ROCS.

  • O. Makrygenni, L. Vanmairis, S. Taourit, F. Launay, A. Shum Cheong Sing, A. Proust, H. Gérard, et R. Villanneau, « Selective Formation of Epoxylimonene Catalyzed by Phosphonyl/Arsonyl Derivatives of Trivacant Polyoxotungstates at Low Temperature », European Journal of Inorganic Chemistry, vol. 2020, nᵒ 7, p. 605-612, févr. 2020.
    Résumé : The catalytic performances of three organophosphonyl/arsonyl derivatives of POMs were evaluated for the epoxidation of limonene in acetonitrile, using aqueous H2O2 as the oxidant. All three W-based POMs catalysts operated without any additional transition-metal ions and displayed excellent conversion for limonene at temperatures varying from 4 to 50 °C. Furthermore, the use of B,α-[NaHAsW9O33{P(O)R}2]3? (R = tBu, -CH2CH2CO2H) complexes led to the complete conversion of limonene to epoxylimonene at 4 °C. The selectivity of the reaction was modulated by varying the reaction solvent, and it was found that allylic reactions were favored in ethanol. The effect of the catalyst protonation was also investigated by DFT calculations, highlighting the role of protons in the epoxidation process.
    Mots-clés : E-POM, Epoxidation, Homogeneous catalysis, Hybrids, Limonene, POLE 2, Polyoxometalates, Renewable resources.
    Pièce jointe Snapshot 161.1 ko (source)

  • T. Martinez, I. Alahyen, G. Lemière, V. Mouriès-Mansuy, et L. Fensterbank, « Straightforward Access to 2-Iodoindolizines via Iodine-Mediated Cyclization of 2-Pyridylallenes », Organic Process Research & Development, vol. 24, nᵒ 5, p. 817-821, mai 2020.
    Résumé : A metal-free access to 2-iodo-1,3-disubstituted indolizines has been developed. The proposed synthesis is relatively simple and efficient and involves the iodine-triggered 5-endo-trig cyclization of 2-pyridylallene precursors. While it can be conducted on a gram scale, the preparation of the precursors is straightforward and does not always require intermediate purifications. The obtained 2-iodoindolizines can be further functionalized through cross-coupling reactions.
    Mots-clés : MACO, POLE 1.
    Pièce jointe Full Text PDF 848 ko (source)

  • X. Meng, X. Lian, X. Li, Q. Ya, T. Li, Y. Zhang, Y. Yang, et Y. Zhang, « Synthesis of 2′-paclitaxel 2-deoxy-2-fluoro-glucopyranosyl carbonate for specific targeted delivery to cancer cells », Carbohydrate Research, vol. 493, p. 108034, 2020.

  • S. Nasri, M. Hajji, M. Guergueb, S. Dhifaoui, V. Marvaud, F. Loiseau, F. Molton, T. Roisnel, T. Guerfel, et H. Nasri, « Spectroscopic, Electrochemical, Magnetic and Structural Characterization of an Hexamethylenetetramine Co(II) Porphyrin Complex – Application in the Catalytic Degradation of Vat Yellow 1 dye », Journal of Molecular Structure, p. 129676, nov. 2020.
    Résumé : In this study, a new cobaltous-(hexamethylenetetramine) [meso-tetra(para-methoxyphenyl)porphyrin complex with the formula [CoII(TMPP)(HMTA)] (I) was synthesized. The

    molecular structure was confirmed in solution by 1H NMR spectroscopy and mass spectrometry methods, and the single crystal X-ray diffraction structure of (I) was determined at both room temperature and low temperature. This species was further characterized by infrared, UV-visible and fluorescence spectroscopies, magnetic susceptibility measurements and cyclic voltammetry. The chemical reactivity behavior was also assessed theoretically through Density Functional Theory (DFT) approach. Magnetic investigation indicates that the Co(II)-HMTA porphyrin (I) species at low temperature is a cobaltous low-spin (S = 1/2) species while at high temperature complex (I) exhibits a spin-crossover low-spin (S = 1/2) ↔ high-spin (S = 3/2). The adsorption kinetic of the “vat yellow 1 dye” was carried out in aqueous solution at pH = 6. The experimental results are better fitted using the pseudo second order model. Furthermore, complex (I) was tested as catalyst in the degradation of the vat yellow 1 dye using an aqueous H2O2 solution and by photodegradation under solar light.
    Mots-clés : E-POM, POLE 2.

  • Y. Nie, M. Zhong, S. Li, X. Li, Y. Zhang, Y. Zhang, et X. He, « Synthesis and Potential Anticancer Activity of Some Novel Selenocyanates and Diselenides », Chemistry & Biodiversity, vol. 17, nᵒ 5, mai 2020.

  • F. Nolay, E. Sevin, M. Létévé, A. Bil, F. Gosselet, K. El Kirat, F. Djedaini-Pilard, S. Morandat, L. Fenart, C. Przybylski, et V. Bonnet, « First step to the improvement of the blood brain barrier passage of atazanavir encapsulated in sustainable bioorganic vesicles », International Journal of Pharmaceutics, vol. 587, p. 119604, 2020.

  • Š. Nováková Lachmanová, L. Pospíšil, J. Šebera, B. Talbi, M. Salmain, et M. Hromadová, « Electrochemical characterization of the artificial metalloenzyme papain-[(η6-arene)Ru(1,10-phenanthroline)Cl]+ », Journal of Electroanalytical Chemistry, vol. 859, p. 113882, 2020.
    Résumé : Electrochemical properties were studied for [(η6-arene)Ru(1,10-phenanthroline)Cl]Cl (arene = C6H5(CH2)2NHCOCH2Cl) organometallic complex 1, protein Papain PAP and its conjugate with organometallic complex 1-PAP. The latter can serve as an artificial metalloenzyme with catalytic activity in transfer hydrogenation. This work demonstrates that AC voltammetry and electrochemical impedance spectroscopy can be used as fast tools to screen the catalytic ability of 1-PAP electrochemically by studies of the catalytic hydrogen evolution reaction (HER). Proteins are known to catalyze this process, but we have shown that additional HER signal associated with the catalytic activity of 1 is observed for its conjugate with Papain 1-PAP.
    Mots-clés : Artificial metalloenzyme, CHEMBIO, Electrochemical admittance and impedance techniques, Papain, POLE 3, Ruthenium(II) complexes.

  • J. A. C. Oliveira, G. Kiala, F. Siopa, A. Bernard, G. Gontard, J. Oble, C. A. M. Afonso, et G. Poli, « Palladium-catalyzed allylic substitution between C-based nucleophiles and 6-azabicyclo[3.1.0]-hex-3-en-2-oxy derivatives: A new selectivity paradigm », Tetrahedron, vol. 76, nᵒ 51, p. 131182, déc. 2020.
    Résumé : The reaction between α-hydroxy-(or α-acetoxy) cyclopenten-aziridines (6-azabicyclo[3.1.0]hex-3-en-2-ols or acetates) and C-based nucleophiles in the presence of Pd(0)-catalysis was investigated. In all the cases studied, the reaction was totally regio- and diastereo-selective, affording a single adduct in moderate to good yields. Specifically, attack of the nucleophile at position 3 of the cyclopentene moiety, anti to the vicinal oxy group, with vinylogous ring opening of the aziridine ring, was observed. When the carbon acid is a very acidic methylene (pKa (DMSO) ≤ 7.3), the resulting adduct is a zwitterion, resulting from an intramolecular proton transfer between the amino group and the carbon acid moiety taking place after the C–C bond formation. A plausible mechanism for this transformation is put forward.
    Mots-clés : Bicyclic aziridine, Palladium catalysis, POLE 1, ROCS, Tsuji-trost reaction.

  • E. Palierse, C. Przybylski, D. Brouri, C. Jolivalt, et T. Coradin, « Interactions of Calcium with Chlorogenic and Rosmarinic Acids: An Experimental and Theoretical Approach », International Journal of Molecular Sciences, vol. 21, nᵒ 14, p. 4948, juill. 2020.
    Résumé : Chlorogenic (CA) and rosmarinic (RA) acids are two natural bioactive hydroxycinnamic acids whose antioxidant properties can be modulated by the chelation of metal ions. In this work, the interactions of these two carboxylic phenols with calcium ions and the impact of such interactions on their antioxidant activity were investigated. UV-Vis absorbance, mass spectroscopy and 1H and 13C liquid NMR were used to identify complexes formed by CA and RA with calcium. Antioxidant activities were measured by the Bois method. Density functional theory (DFT) calculations were performed to evaluate the most stable configurations and correlated with NMR data. Taken together, these data suggest that calcium ions mainly interact with the carboxylate groups of both molecules but that this interaction modifies the reactivity of the catechol groups, especially for RA. These results highlight the complex interplay between metal chelation and antioxidant properties of natural carboxylic phenols.
    Mots-clés : CSOB, POLE 3.

  • V. Pellas, D. Hu, Y. Mazouzi, Y. Mimoun, J. Blanchard, C. Guibert, M. Salmain, et S. Boujday, « Gold Nanorods for LSPR Biosensing: Synthesis, Coating by Silica, and Bioanalytical Applications », Biosensors, vol. 10, nᵒ 10, p. 146, 2020.
    Résumé : Nanoparticles made of coinage metals are well known to display unique optical properties stemming from the localized surface plasmon resonance (LSPR) phenomenon, allowing their use as transducers in various biosensing configurations. While most of the reports initially dealt with spherical gold nanoparticles owing to their ease of synthesis, the interest in gold nanorods (AuNR) as plasmonic biosensors is rising steadily. These anisotropic nanoparticles exhibit, on top of the LSPR band in the blue range common with spherical nanoparticles, a longitudinal LSPR band, in all respects superior, and in particular in terms of sensitivity to the surrounding media and LSPR-biosensing. However, AuNRs synthesis and their further functionalization are less straightforward and require thorough processing. In this paper, we intend to give an up-to-date overview of gold nanorods in LSPR biosensing, starting from a critical review of the recent findings on AuNR synthesis and the main challenges related to it. We further highlight the various strategies set up to coat AuNR with a silica shell of controlled thickness and porosity compatible with LSPR-biosensing. Then, we provide a survey of the methods employed to attach various bioreceptors to AuNR. Finally, the most representative examples of AuNR-based LSPR biosensors are reviewed with a focus put on their analytical performances.
    Mots-clés : CHEMBIO, gold nanorods, localized surface plasmon resonance (LSPR), POLE 3, silica coating, surface functionalization.

  • L. Plet, G. Delecourt, M. Hanafi, N. Pantoustier, G. Pembouong, P. Midoux, V. Bennevault, et P. Guégan, « Controlled star poly(2-oxazoline)s: Synthesis, characterization », European Polymer Journal, vol. 122, p. 109323, janv. 2020.
    Résumé : Poly(2-methyl-2-oxazoline) and poly(2-ethyl-2-oxazoline) star polymers with 3, 4 and 6 arms are synthesized from pluritriflate initiators. Characterization of the topology was achieved by NMR, SEC and kinetic studies. The initiation step of 2-ethyl-2-oxazoline being slow, heterogeneous star polymers in arm molar masses are obtained for low molar mass polymers. However, for both monomers, high molar mass homogeneous star polymers are obtained. A fast initiation is observed for the polymerization of 2-methyl-2-oxazoline, providing a control of the topology even at low molar mass. In the studied molar mass range, linear kinetic first order plots and linear molar mass as a function of conversion are obtained for both monomers, suggesting living polymerizations.
    Mots-clés : 2oxazoline polymerization, Pluritriflate initiators, POLE 4, POLYMERES, Star polymers.

  • V. Puchelle, H. Du, N. Illy, et P. Guégan, « Polymerization of epoxide monomers promoted by tBuP4 phosphazene base: a comparative study of kinetic behavior », Polymer Chemistry, vol. 11, nᵒ 21, p. 3585-3592, juin 2020.
    Résumé : The kinetics of the anionic ring-opening polymerizations (AROP) of epoxide monomers, 1,2-epoxybutane (BO), 1,2-epoxypropane (PO), tert-butyl glycidyl ether (tBuGE), allyl glycidyl ether (AGE), benzyl glycidyl ether (BnGE), and ethoxyethyl glycidyl ether (EEGE), was investigated using benzyl alcohol/tBuP4 as the initiating system. All the polymerizations proceed in a controlled manner following a first order kinetics with respect to the monomer. The influence of the side chains borne by the oxirane ring was evidenced. Propagating centers derived from epoxide bearing heretoatom-containing side chains display higher reactivities and propagation rates. A reactivity scale has been established and is as follows, kp,BnGE > kp,AGE > kp,EEGE ≫ kp,tBuGE ≈ kp,PO > kp,BO. Using BO as the model monomer and different initiator concentrations, the nature of the propagating species has been identified as ion pairs. The influence of a Lewis acid addition on the monomer reactivities and on the control of the polymerization was also investigated. In the presence of triisobutylaluminum (iBu3Al), polymerization kinetics was faster but led to a broadening of the molar mass distributions. The monomer reactivity scale was also strongly modified with kp,PO > kp,BO > kp,EEGE ≈ kp,AGE > kp,BnGE ≈ kp,tBuGE. The polymerizations of PO, BO and tBuGE follow zero order kinetics which is not the case for the other oxirane monomers.
    Mots-clés : pole 4, POLYMERES.
    Pièce jointe Full Text PDF 923.5 ko (source)

  • X. Qi, S. Pillet, C. Graaf, M. Magott, E. ‐E. Bendeif, P. Guionneau, M. Rouzières, V. Marvaud, O. Stefańczyk, D. Pinkowicz, et C. Mathonière, « Photoinduced Mo−CN Bond Breakage in Octacyanomolybdate Leading to Spin Triplet Trapping », Angewandte Chemie International Edition, vol. 59, nᵒ 8, p. 3117-3121, févr. 2020.

  • C. Qin, T. Matsushima, W. J. Potscavage, A. S. D. Sandanayaka, M. R. Leyden, F. Bencheikh, K. Goushi, F. Mathevet, B. Heinrich, G. Yumoto, Y. Kanemitsu, et C. Adachi, « Triplet management for efficient perovskite light-emitting diodes », Nature Photonics, vol. 14, nᵒ 2, p. 70-75, févr. 2020.
    Résumé : Perovskite light-emitting diodes are promising for next-generation lighting and displays because of their high colour purity and performance1. Although the management of singlet and triplet excitons is fundamental to the design of efficient organic light-emitting diodes, the nature of how excitons affect performance is still not clear in perovskite2–4 and quasi-two-dimensional (2D) perovskite-based devices5–9. Here, we show that triplet excitons are key to efficient emission in green quasi-2D perovskite devices and that quenching of triplets by the organic cation is a major loss path. Employing an organic cation with a high triplet energy level (phenylethylammonium) in a quasi-2D perovskite based on formamidinium lead bromide yields efficient harvesting of triplets. Furthermore, we show that upconversion of triplets to singlets can occur, making 100% harvesting of electrically generated excitons potentially possible. The external quantum and current efficiencies of our green (527 nm) devices reached 12.4% and 52.1 cd A−1, respectively.
    Mots-clés : POLE 4, POLYMERES.

  • J. P. Rada, J. Forté, G. Gontard, V. Corcé, M. Salmain, et N. A. Rey, « Isoxazole-Derived Aroylhydrazones and Their Dinuclear Copper(II) Complexes Show Antiproliferative Activity on Breast Cancer Cells with a Potentially Alternative Mechanism Of Action », ChemBioChem, vol. 21, nᵒ 17, p. 2474-2486, 2020.
    Résumé : Abstract This paper reports the design, synthesis and cytotoxicity studies of two new isoxazole-derived aroylhydrazone ligands and their dinuclear copper(II) complexes. Compounds were fully characterized by various spectroscopic and analytical techniques. The molecular structures of four derivatives were confirmed by X-ray crystallography. The stability of the ligands and the complexes in aqueous medium was monitored spectroscopically. Both the ligands and the complexes were shown to interact with calf thymus DNA (ct-DNA). Additionally, structures containing a phenol pendant arm were significantly more cytotoxic than those carrying a pendant pyridine substituent, reaching sub-micromolar IC50 values on the triple-negative human breast cancer cell line MDA-MB-231. The metal chelation and transchelation ability of the compounds towards FeII, FeIII and ZnII ions was explored as a possible mechanism of action of these compounds.
    Mots-clés : antitumor agents, aroylhydrazonic ligands, CHEMBIO, copper(II) complexes, cytotoxicity, DNA, POLE 3.
    Note Note
    <p>doi: 10.1002/cbic.202000122</p>

  • M. A. Rahman, S. - X. Guo, M. Laurans, G. Izzet, A. Proust, A. M. Bond, et J. Zhang, « Thermodynamics, Electrode Kinetics, and Mechanistic Nuances Associated with the Voltammetric Reduction of Dissolved [n-Bu4N]4[PW11O39{Sn(C6H4)C≡C(C6H4)(N3C4H10)}] and a Surface-Confined Diazonium Derivative », ACS Applied Energy Materials, vol. 3, nᵒ 4, p. 3991-4006, avr. 2020.
    Résumé : The power of Fourier-transformed large amplitude alternating current voltammetry (FTACV) has been applied to parameterize the reduction of the phosphotungstate [PW11O39{Sn(C6H4)C≡C(C6H4)(N3C4H10)}]4– polyoxometalate (POM) (KWSn[N3C4H10]4–/5–/6– processes) at glassy carbon (GC), gold (Au), and platinum (Pt) electrodes as well as its GC surface-confined KWSn[−]4–-grafted diazonium derivative in acetonitrile (0.10 M [n-Bu4N][PF6]). The thermodynamics (E0) and heterogeneous electron-transfer kinetics (k0 and α) were estimated using the Butler–Volmer relationship. FTACV provides access to significantly more detailed mechanistic information related to nonconformance to the theory than widely used DC voltammetric methods, especially with the more intricate surface-confined electrochemistry. Parameterization, the level of agreement, and systematic variations between experimental and simulated data were established by both an experimenter-controlled heuristic method and by a computationally efficient data optimization approach that employed parameter space searches restricted in scope by knowledge of the heuristically based estimations. The first electron transfer process for both acetonitrile-soluble KWSn[N3C4H10]4– and surface-confined KWSn[−]4– is always significantly faster than the second. The electrode dependence order is kGC0 > kAu0 > kPt0 for the KWSn[N3C4H10]4–/5– process. The relatively slower electrode kinetics found for reduction of KWSn[N3C4H10]4– as compared to some other monomeric Keggin POMs may be due to the long organic chain hindering the approach of the POM to the electrode surface, although differences in ion-pairing and other factors also may play a role. Subtle, but systematic, differences identified in comparisons of experimental and simulated voltammetry give rise to apparently data analysis method dependent parameterization and are discussed in terms of nuances not accommodated in the modeling. In the solution-phase voltammetry, data obtained by an electrochemical quartz crystal microbalance and other techniques are consistent with solid adhering to and modifying the electrode surface following reduction of KWSn[N3C4H10]4– to KWSn[N3C4H10]5–. Kinetic and thermodynamic dispersions present in the heterogeneous KWSn[−]4–-grafted electrode are probable causes of nonideality detected in the surface-confined voltammetry of this material. Thus, FTACV gives valuable insights into what is needed to provide a more realistic description of the polyoxometalate/electrode interface in polyoxometalate electrochemistry by revealing subtle nuances that are often overlooked.
    Mots-clés : E-POM, POLE 2.
    Pièce jointe Full Text PDF 7.8 Mo (source)

  • R. Ramos, J. M. Zimbron, S. Thorimbert, L. - M. Chamoreau, A. Munier, C. Botuha, A. Karaiskou, M. Salmain, et J. Sobczak-Thépot, « Insights into the antiproliferative mechanism of (C^N)-chelated half-sandwich iridium complexes », Dalton Transactions, 2020.
    Résumé : Transition metal-based anticancer compounds, as alternative to platinum derivatives, are raising scientific interest as they may present distinct although poorly understood mechanisms of action. We used a structure-activity relationship-based methodology to investigate the chemical and biological features of a series of ten (C^N)-chelated half-sandwich iridiumIII complexes of the general formula [IrCp*(phox)Cl], where (phox) is a 2-phenyloxazoline ligand forming a 5-membered metallacycle. This series of compounds undergoes a fast exchange of their chlorido ligand once solubilised in DMSO. They were cytotoxic to HeLa cells with IC50 values in the micromolar range and induced a rapid activation of caspase-3, an apoptosis marker. In vitro, the oxidative power of all the complexes towards NADH was highlighted but only the complexes bearing substituents on the oxazoline ring were able to produce H2O2 at the micromolar range. However, we demonstrated using a powerful HyPer protein redox sensor-based flow cytometry assay that most complexes rapidly raised intracellular levels of H2O2. Hence, this study shows that oxidative stress can partly explain the cytotoxicity of these complexes on the HeLa cell line and gives a first entry to their mechanism of action
    Mots-clés : CHEMBIO, POLE 3.

  • B. Rasolonjatovo, N. Illy, V. Bennevault, J. Mathé, P. Midoux, T. L. Gall, T. Haudebourg, T. Montier, P. Lehn, B. Pitard, H. Cheradame, C. Huin, et P. Guégan, « Temperature-Sensitive Amphiphilic Non-Ionic Triblock Copolymers for Enhanced In Vivo Skeletal Muscle Transfection », Macromolecular Bioscience, vol. 20, nᵒ 3, p. 1900276, 2020.
    Résumé : It is reported that low concentration of amphiphilic triblock copolymers of pMeOx-b-pTHF-b-pMeOx structure (TBCPs) improves gene expression in skeletal muscle upon intramuscular co-injection with plasmid DNA. Physicochemical studies carried out to understand the involved mechanism show that a phase transition of TBCPs under their unimer state is induced when the temperature is elevated from 25 to 37 °C, the body temperature. Several lines of evidences suggest that TBCP insertion in a lipid bilayer causes enough lipid bilayer destabilization and even pore formation, a phenomenon heightened during the phase transition of TBCPs. Interestingly, this property allows DNA translocation across the lipid bilayer model. Overall, the results indicate that TBCPs exhibiting a phase transition at the body temperature is promising to favor in vivo pDNA translocation in skeletal muscle cells for gene therapy applications.
    Mots-clés : amphiphilic copolymers, in vivo transfection, LCST, POLE 4, poly(2-methyl-2-oxazoline), POLYMERES, skeletal muscle.
    Pièce jointe Full Text PDF 1.3 Mo (source)

  • Y. Ren, J. Forte, K. Cheaib, N. Vanthuyne, L. Fensterbank, H. Vezin, M. Orio, S. Blanchard, et M. Desage-El Murr, « Optimizing Group Transfer Catalysis by Copper Complex with Redox-Active Ligand in an Entatic State », Iscience, vol. 23, nᵒ 3, p. UNSP 100955, mars 2020.
    Résumé : Metalloenzymes use earth-abundant non-noble metals to perform high-fidelity transformations in the biological world. To ensure chemical efficiency, metalloenzymes have acquired evolutionary reactivity-enhancing tools. Among these, the entatic state model states that a strongly distorted geometry induced by ligands around a metal center gives rise to an energized structure called entatic state, strongly improving the reactivity. However, the original definition refers both to the transfer of electrons or chemical groups, whereas the chemical application of this concept in synthetic systems has mostly focused on electron transfer, therefore eluding chemical transformations. Here we report that a highly strained redox-active ligand enables a copper complex to perform catalytic nitrogen- and carbon-group transfer in as fast as 2 min, thus exhibiting a strong increase in reactivity compared with its unstrained analogue. This report combines two reactivity-enhancing features from metalloenzymes, entasis and redox cofactors, applied to group-transfer catalysis.
    Mots-clés : aziridination, cu, galactose-oxidase, generation, metal-complexes, models, oxidation, POLE 1, POLE 2, radicals, reactivity, site.
    Pièce jointe Texte intégral 19.8 Mo (source)

  • M. Roy, V. Berezhnaia, M. Villa, N. Vanthuyne, M. Giorgi, J. - V. Naubron, S. Poyer, V. Monnier, L. Charles, Y. Carissan, D. Hagebaum‐Reignier, J. Rodriguez, M. Gingras, et Y. Coquerel, « Stereoselective Syntheses, Structures, and Properties of Extremely Distorted Chiral Nanographenes Embedding Hextuple Helicenes », Angewandte Chemie International Edition, vol. 59, nᵒ 8, p. 3264-3271, 2020.
    Résumé : We report a molecular design and concept using π-system elongation and steric effects from helicenes surrounding a triphenylene core toward stable chiral polycyclic aromatic hydrocarbons (PAHs) with a maximal π-distortion to tackle their aromaticity, supramolecular and molecular properties. The selective syntheses, and the structural, conformational and chiroptical properties of two diastereomeric large multi-helicenes of formula C90H48 having a triphenylene core and embedding three [5]helicene units on their inner edges and three [7]helicene units at their periphery are reported based on diastereoselective and, when applicable, enantiospecific Yamamoto-type cyclotrimerizations of racemic or enantiopure 9,10-dibromo[7]helicene. Both molecules have an extremely distorted triphenylene core, and one of them exhibits the largest torsion angle recorded so far for a benzene ring (twist=36.9°).
    Mots-clés : aromaticity, helicenes, POLE 1, polycyclic aromatic hydrocarbons, ROCS, stereoselectivity, strained molecules.

  • R. Sala, F. Roudesly, L. F. Veiros, G. Broggini, J. Oble, et G. Poli, « Ru-Catalyzed Carbonylative Murai Reaction: Directed C3-Acylation of Biomass-Derived 2-Formyl Heteroaromatics », Advanced Synthesis & Catalysis, vol. 362, nᵒ 12, p. 2486-2493, 2020.
    Résumé : The Murai reaction is a ruthenium-catalyzed transformation leading to alkylated arenes through the C−C bond formation between an alkene and an arene bearing a directing group. Discovered in the nineties, this useful C−H activation based coupling has been the object of intense study since its discovery. After having studied the Murai reaction on 2-formylfurans of biomass derivation, we describe here the carbonylative version applied to 2-formylfurans, 2-formylpyrrols and 2-formylthiophenes. This acylation reaction takes place regioselectively at C3 position of the heterocyclopentadienes thanks to the installation of removable imine directing groups. The transformation can be achieved by treating the two reaction partners with a catalytic amount of Ru3(CO)12, in toluene at 120–150 °C, after CO bubbling, at atmospheric pressure. DFT computations of the full catalytic cycle help in deciphering the mechanism of this transformation, and to rationalize the different behaviors depending on the nature of imine directing groups.
    Mots-clés : carbonylation, C−H activation, homogeneous catalysis, Murai reaction, POLE 1, ROCS, ruthenium.
    Pièce jointe Full Text PDF 8.3 Mo (source)

  • R. Salles, B. Abécassis, E. Derat, D. Brouri, A. Bernard, Q. Zhang, A. Proust, C. Desmarets, et G. Izzet, « Hierarchical Self-Assembly of Polyoxometalate-Based Organo Palladium(II) Metallomacrocycles via Electrostatic Interactions », Inorganic Chemistry, vol. 59, nᵒ 4, p. 2458-2463, févr. 2020.
    Résumé : The design and synthesis of a supramolecular square composed of polyoxometalate-based hybrid donors and ethylenediamine palladium(II) nodes are reported. The structure of the metallomacrocycle scaffold was inferred by diffusion NMR, small-angle X-ray scattering (SAXS), and molecular modeling. The metallomacrocycle scaffold that contains negatively and positively charged subunits can further self-assemble owing to a competition between the solvation energy of the discrete species and intermolecular electrostatic interactions. When the dissociating character of the solvent was lowered or when in the presence of a protic solvent, different types of multiscale organizations (vesicles and pseudo-1D structures) were selectively formed and were characterized by SAXS and transmission electron microscopy.
    Mots-clés : ARC, E-POM, MACO, POLE 1, POLE 2.
    Pièce jointe Full Text PDF 2.1 Mo (source)

  • M. Salmain, N. Fischer-Durand, et B. Rudolf, « Bioorthogonal Conjugation of Transition Organometallic Complexes to Peptides and Proteins: Strategies and Applications », European Journal of Inorganic Chemistry, vol. 2020, nᵒ 1, p. 21-25, 2020.
    Résumé : The advent of bioorthogonal chemistry has revolutionized the common practices in protein bioconjugation and contributed to a large extent to the development of chemical biology, a discipline aimed at studying biological/biochemical processes/events in their natural setting (living cells, whole organisms) using dedicated chemical tools. This minireview intends to provide an up-to-date overview on the various bioorthogonal strategies implemented for the conjugation of transition organometallic entities to peptides, peptide nucleic acids and proteins with a focus on targeted applications, i.e. fluorescence- or radio-labeling for imaging, controlled delivery of therapeutic agents and bioanalysis.
    Mots-clés : CHEMBIO, Click chemistry, Cycloaddition, Ferrocene, Manganese, Peptide nucleic acids, POLE 3.
    Note Note
    <p>doi: 10.1002/ejic.201900810</p>
    Note Note
    <p>doi: 10.1002/ejic.201900810</p>

  • M. Sellin, V. Marvaud, et M. Malischewski, « Isolation and Structural Characterization of Eightfold Protonated Octacyanometalates [M(CNH) <sub>8</sub> ] <sup>4+</sup> (M=Mo <sup>IV</sup> , W <sup>IV</sup> ) from Superacids », Angewandte Chemie International Edition, vol. 59, nᵒ 26, p. 10519-10522, juin 2020.
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