Nos tutelles



Accueil > Publications


publié le , mis à jour le


  • F. Chemla et A. Perez-Luna, « 2.5 Radical–Polar Crossover Reactions », in Free Radicals: Fundamentals and Applications in Organic Synthesis 2, 2021ᵉʳ éd., Thieme Verlag, 2021.
    Résumé : Radical–polar crossover reactions, that is, single-electron redox events allowing for the interconversion between radical and ionic intermediates, make it possible to connect radical and polar processes in the same synthetic transformation. Such a combination is the basis of much original synthetic methodology, which is particularly useful in the context of domino, tandem, or multicomponent reactions. This chapter comprehensively covers the field of radical–polar crossover reactions, with a primary emphasis on transformations wherein both the radical and polar processes provide synthetic elaboration.
    Mots-clés : Organic Chemistry, POLE 1, ROCS.
    Pièce jointe Snapshot 617.9 ko (source)

  • S. Curpanen, G. Poli, J. Oble, et A. Perez‐Luna, « C(sp2)−Si Bond Functionalization through Intramolecular Activation by Alkoxides », European Journal of Organic Chemistry, vol. 2021, nᵒ 7, p. 1055-1071, 2021.
    Résumé : Organosilicon reagents are invaluable tools in the hands of the modern chemist that allow accomplishing a number of synthetically useful transformations. While some are standard reactions, others are more complex transformations, such as the Brook rearrangement and its variants. This carbon-to-oxygen silyl migration represents a privileged method to generate transient carbanionic species well suited to undergo functionalization upon electrophilic substitution in the presence of an electrophile. This minireview focuses on recent advances in C(sp2)−Si bond functionalization through intramolecular activation by alkoxides. The key elements of reactivity will be highlighted in the introduction to allow the proper understanding of the migration process. Then, an overview of the reactivity of substrates incorporating the C(sp2)−Si motif and their synthetic applications will be provided.
    Mots-clés : Anion Relay Chemistry, Brook rearrangement, Hiyama cross-coupling, POLE 1, ROCS, Silyl migration, Synthetic methods.
    Pièce jointe Snapshot 484.1 ko (source)

  • H. Dossmann, L. Fontaine, T. Weisgerber, V. Bonnet, E. Monflier, A. Ponchel, et C. Przybylski, « First Steps to Rationalize Host–Guest Interaction between α-, β-, and γ-Cyclodextrin and Divalent First-Row Transition and Post-transition Metals (Subgroups VIIB, VIIIB, and IIB) », Inorganic Chemistry, vol. 60, nᵒ 2, p. 930-943, janv. 2021.
    Mots-clés : CSOB, Cyclodextrin, POLE 3.

  • D. Gatineau, H. Dossmann, H. Clavier, A. Memboeuf, L. Drahos, Y. Gimbert, et D. Lesage, « Ligand effects in gold-carbonyl complexes: evaluation of the bond dissociation energies using blackbody infrared radiative dissociation », International Journal of Mass Spectrometry, p. 116545, févr. 2021.

  • A. Harbi, Y. L. Godec, Y. Li, H. Moutaabbid, S. Benmokhtar, et M. Moutaabbid, « Experimental and theoretical investigation of the electronic, magnetic, and optical properties of a new oxyphosphate, Ni0.25Mn0.25TiO(PO4) », Journal of Physics and Chemistry of Solids, vol. 148, p. 109633, 2021.
    Résumé : The structural, magnetic, and optical properties of a new oxyphosphate, Ni0.25Mn0.25TiOPO4, have been investigated by X-ray diffraction (XRD) analysis, magnetic FC-ZFC measurements, and vibrational spectroscopy (Raman, IR, WDS, and UV/visible). XRD analysis showed that the compound crystallizes in a monoclinic structure, space group P21/c, with unit cell parameters of a = 7.3758(2) Å, b = 7.3255(2) Å, c = 7.3448(2) Å, and β = 120.25(2)°. Elemental analysis of the powder confirmed the presence of Ni, Mn, Ti, and P therein. Raman and IR spectra show strong bands at 749 and 787 cm−1, respectively, attributable to the vibration of –Ti–O–Ti–O– bonds in infinite chains. Magnetic studies have been performed in the temperature range from 2 to 300 K. The results revealed a weak antiferromagnetic coupling between spins in Ni0.25Mn0.25TiOPO4. The band-gap energy was estimated as Eg = 1.99 eV based on UV/Vis spectrophotometry. To better understand the experimental data, density functional theory (DFT) computations were performed within the generalized gradient approximation (GGA) and GGA + U. The partial density of states (PDOS) shows strong hybridization between O 2p, Mn 3d, and Ni 3d in the valence band and between Mn 3d, Ni 3d, and Ti 3d in the conduction band.
    Mots-clés : ERMMES, POLE 2.

  • E. Rathahao-Paris, S. Alves, et A. Paris, « High-Throughput Metabolomics Using Flow Injection Analysis and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry », in Metabolomics, vol. 159, New York, NY: Humana, 2021, p. 9-23.
    Résumé : The hyphenation of flow injection analysis (FIA) with Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) is an efficient approach usable to perform high throughput and very high resolution metabolomic data acquisition. Instrumental and analytical conditions for performing FIA-MS are provided. The procedure to optimize dilution factor of biological samples as well as to evaluate quality of acquisition data are also described. In this protocol, urine is chosen as a matrix example to illustrate the application of procedures. Last, some indications on an adapted data processing are given.
    Mots-clés : CSOB, POLE 3.

  • A. Vessières, Y. Wang, M. J. McGlinchey, et G. Jaouen, « Multifaceted chemical behaviour of metallocene (M = Fe, Os) quinone methides. Their contribution to biology », Coordination Chemistry Reviews, vol. 430, p. 213658, 2021.


  • Abdmouleh, Fatma, El Arbi, Mehdi, Hajer, Ben Saad, Jellali, Karim, Etata, Emna, Amara, Ibtissem Ben, Pigeon, Pascal, Hanen, Ben Hassen, Top, Siden, Jaouen, Gérard, Hammami, Riadh, Mamdouh, Ben Ali, et Gupta, Girish Kumar, « Antimicrobial, Antitumor and Side Effects Assessment of a Newly Synthesized Tamoxifen Analog », Current Topics in Medicinal Chemistry, vol. 20, nᵒ 25, p. 2281-2288, sept. 2020.
    Résumé : Background: Tamoxifen citrate is a very prevalent drug marketed under several trade names like Apo-Tamox, Nolvadex, Tamec, Tamizam, and Tamoplex. This molecule is approved by the FDA for breast cancer treatment. Some studies have shown that tamoxifen has anti-tuberculosis and antiparasitic activities. Like any drug, tamoxifen possesses side effects, more or less dangerous. Aims: Basically, this work is a comparative study that aims to: primarily compare the antimicrobial and antitumor activities of tamoxifen and a newly synthesized tamoxifen analog; and to determine the molecule with lesser side effects. Methods: Three groups of mice were injected with tamoxifen citrate and compound 2(1,1-bis[4-(3- dimethylaminopropoxy)phenyl]-2-phenyl-but-1-ene dihydrochloride) at doses corresponding to C1 (1/10), C2 (1/50), and C3 (1/100) to compound 2 lethal dose (LD50 = 75 mg/kg) administered to adult mice. A group of noninjected mice served as a study control. Results: Experimental results suggest that compound 2 has better antitumor and antimicrobial activity than tamoxifen citrate besides its lower toxicity effects. Conclusion: The results obtained from the present study confirmed the antitumor and antimicrobial effect of tamoxifen citrate and its hematological side effects. Compound 2 seems to be more effective than tamoxifen citrate for antitumor and antimicrobial treatment while having less hematological side effects and less disruption of the blood biochemical parameters. These findings encourage us to perform further studies on compound 2 and test it for other therapeutic uses for which tamoxifen was found effective.
    Mots-clés : POLE 3.

  • S. Alves, A. Paris, et E. Rathahao-Paris, « Mass spectrometry-based metabolomics for an in-depth questioning of human health », in Advances in Clinical Chemistry, Elsevier, 2020, p. S0065242320300214.

  • N. Audureau, F. Coumes, J. - M. Guigner, T. P. T. Nguyen, C. Ménager, F. Stoffelbach, et J. Rieger, « Thermoresponsive properties of poly(acrylamide-co-acrylonitrile)-based diblock copolymers synthesized (by PISA) in water », Polymer Chemistry, vol. 11, nᵒ 37, p. 5998-6008, sept. 2020.
    Résumé : In this present work, we report the synthesis of UCST-thermoresponsive diblock copolymers using reversible addition fragmentation chain transfer (RAFT) polymerization in aqueous media. A water-soluble poly(N,N-dimethylacrylamide) macromolecular chain transfer agent (PDMAc macroRAFT) is used to promote and control the copolymerization of acrylamide and acrylonitrile in water and obtain PDMAc-b-P(AAm-co-AN) diblock copolymers. The fAN,0 and the length of the thermosensitive block (DPn) are systematically varied, in order to study their influence on the thermoresponsiveness of the block copolymers. A good blocking efficiency is generally evidenced by size exclusion chromatography. Remarkably, amphiphilic copolymer nanoparticles are formed in situ for the highest fAN,0. This is indeed the first time that such particles are produced by a polymerization-induced self-assembly (PISA) process. The morphology of the in situ formed nanoparticles and their behavior with temperature are studied by means of dynamic light scattering (DLS), (cryogenic) transmission electron microscopy ((cryo-)TEM) and turbidimetry. Spherical and worm-like nanoparticles are formed which exhibit unexpected properties, such as an unprecedented heating-induced worm-to-sphere morphological transition in water.
    Mots-clés : POLE 4, POLYMERES.
    Pièce jointe Full Text PDF 1.7 Mo (source)

  • P. Bayat, D. Lesage, et R. B. Cole, « Tutorial: Ion activation in tandem Mass spectrometry using ultra-high resolition spectroscopy », Mass Spectrometry Reviews, p. mas.21623, févr. 2020.

  • L. Bedoin, S. Alves, et J. - F. Lambert, « Origins of Life and Molecular Information: Selectivity in Mineral Surface-Induced Prebiotic Amino Acid Polymerization », ACS Earth and Space Chemistry, p. acsearthspacechem.0c00183, sept. 2020.

  • A. Beghennou, K. Passador, A. Passador, V. Corcé, S. Thorimbert, et C. Botuha, « Synthetic Strategy Studies for a Concise Access to Functionalized Pyrano[4,3-b]pyridin-7-ones: An Entry to Semi-Rigid Analogs of Antihistamines », European Journal of Organic Chemistry, vol. 2020, nᵒ 36, p. 5880-5889, sept. 2020.
    Résumé : We report short and efficient syntheses of polyfunctionalized 5,8-dihydro-7H-pyrano[4,3-b]pyridin-7-ones and 1,4-dihydro-3H-pyrano[4,3-c]pyridin-3-ones which can be considered as new aza analogs of 3-isochromanones and as promising scaffolds for medicinal chemistry. Depending on the nature of the substituent, three different and complementary synthetic methodologies were used allowing the introduction of significant diversity in the substituent on the lactone ring of the pyranopyridinones. The selective α-arylation of nitrile (SNAr) and tert-butyl ester enolate (Pd catalyzed) followed by an acidic mediated lactonisation gives access to original C8-functionalized pyrano[4,3-b]pyridin-7-ones and a seleno-mediated cyclization to C1-functionalized pyrano[4,3-c]pyridin-3-ones. We have also applied the outlined synthetic methodologies to the preparation of potential semi-rigid analogs of antihistamines.
    Mots-clés : Antihistamines, CHEMBIO, Pinner reaction, POLE 3, Pyridopyridinones, Seleno-mediated cyclization, δ-Lactone.
    Note Note
    <p>doi: 10.1002/ejoc.202001016</p>

  • Y. Ben M’Barek, T. Rosser, J. Sum, S. Blanchard, F. Volatron, G. Izzet, R. Salles, J. Fize, M. Koepf, M. Chavarot-Kerlidou, V. Artero, et A. Proust, « Dye-Sensitized Photocathodes: Boosting Photoelectrochemical Performances with Polyoxometalate Electron Transfer Mediators », ACS Applied Energy Materials, vol. 3, nᵒ 1, p. 163-169, janv. 2020.

  • A. Benchohra, C. Méthivier, J. Landoulsi, D. Kreher, et R. Lescouëzec, « Electrospray ionization: an efficient approach to deposit polymetallic molecular switches onto gold surfaces », Chemical Communications, vol. 56, nᵒ 48, p. 6587-6589, 2020.
    Résumé : Electrospray ionization (EI) deposition is proven efficient in obtaining monolayers of a polymetallic charge transfer complex on gold surfaces. , Electrospray ionization (EI) deposition is proven efficient in obtaining monolayers of a polymetallic charge transfer complex on gold surfaces. The molecule's integrity is monitored by using PM-IRRAS and XPS. This approach broadens the perspective of molecular magnetic switch deposition, which is currently dominated by the thermal evaporation of monometallic spin crossover (SCO) complexes.
    Mots-clés : ERMMES, POLE 2.

  • B. Bertrand, C. Botuha, J. Forté, H. Dossmann, et M. Salmain, « A bis-chelating (O^N^O)/(N^N) ligand for the synthesis of heterobimetallic Pt(II)/Re(I) complexes: tools for the optimization of a new class of Pt(II) anticancer agents. », Chemistry – A European Journal, vol. 26, nᵒ 56, p. 12846-12861, 2020.
    Résumé : The two independent (O^N^O) and (N^N) coordination sites of a newly synthesized bis 2-(hydroxyphenyl)-1,2,4-triazole platform have been exploited to prepare four monometallic neutral (O^N^O)Pt(II) complexes carrying DMSO, pyridine, triphenylphosphine or N-heterocyclic carbene (NHC) as fourth ligand. Then the second (N^N) coordination site was used to introduce an IR-active rhenium tricarbonyl entity, affording the four corresponding heterobimetallic neutral Pt(II)/Re(I) complexes as well as a cationic Pt(II)/Re(I) derivative. X-ray crystallographic studies showed that distortion of the organic platform occurred to accommodate the coordination geometry of both metal centers. No ligand exchange and no transchelation occurred upon incubation of the Pt(II) complexes in aqueous environment or in the presence of Fe(III), respectively. The ligand and the complexes antiproliferative activity was first screened on the triple negative breast cancer cell line MDA-MB-231. Then the IC 50 of the most active candidates was determined on a wider panel of human cancer cells (MDA-MB-231, MCF-7 and A2780) as well as on a non-tumorigenic cell line (MCF-10F). Low micromolar activities were reached for the complexes carrying a DMSO ligand, making them the first examples of highly active though hydrolytically stable Pt(II) complexes. Finally, the characteristic mid-IR signature of the Re(CO) 3 fragment in the Pt/Re heterobimetallic complexes was used to quantify their uptake in breast cancer cells.
    Mots-clés : cancer, CHEMBIO, CSOB, heterobimetallic, pincer, platinum, POLE 3, rhenium.
    Note Note
    <p>doi: 10.1002/chem.202001752</p>

  • B. Bertrand, G. Gontard, C. Botuha, et M. Salmain, « Pincer-based heterobimetallic Pt(II)/Ru(II), Pt(II)/Ir(III) and Pt(II)/Cu(I) complexes: synthesis and evaluation antiproliferative properties », European Journal of Inorganic Chemistry, vol. 2020, nᵒ 35, p. 3370-3377, sept. 2020.
    Résumé : Platinum pincer-based complexes [(O^N^O)Pt(L)] (L = DMSO, pyridine, triphenylphosphine or 1,3-dimethylbenzimidazol-2-ylidene) carrying an (N^N) coordination site were used as starting materials to synthesize a series of seven cationic heterobimetallic Pt(II)/Ru(II), Pt(II)/Ir(III) and Pt(II)/Cu(I) presenting a [( p- cymene)RuCl] + , a [(Cp*)IrCl] + (Cp* = ? 5 -pentamethylcyclopentadienyl) and a [(NHC iPr )Cu] + (NHC iPr = 1,3-bis(2,6-diisopropylphenyl)imidazole-2-ylidene) moiety respectively. The X-ray structure of one of the bimetallic Pt(II)/Ir(III) complexes showed a distortion of the organic platform to accommodate the coordination geometry of both metal centers as already observed for previous Pt(II)/Re(I) complexes. The antiproliferative activity of the complexes was first screened on the triple negative breast cancer cell line MDA-MB-231. Then the IC 50 of the most active candidates was determined on a wider panel of human cancer cells (MDA-MB-231, MCF-7 and A2780) as well as on a non-tumorigenic cell line (MCF-10A). The most toxic compound, namely the Pt(II)/Cu(I) heterobimetallic complex 4c showed an antiproliferative activity down to the nanomolar level.
    Mots-clés : Bioorganometallic chemistry, cancer, CHEMBIO, heterobimetallic complexes, platinum, POLE 3, Synthesis.
    Note Note
    <p>doi: 10.1002/ejic.202000717</p>

  • P. Biais, O. Colombani, L. Bouteiller, F. Stoffelbach, et J. Rieger, « Unravelling the formation of BAB block copolymer assemblies during PISA in water », Polymer Chemistry, vol. 11, nᵒ 28, p. 4568-4578, juill. 2020.
    Résumé : The mechanism of formation of associative BAB triblock copolymers through aqueous polymerization-induced self-assembly (PISA) is investigated for the first time, on copolymers constituted of a hydrophilic poly(N,N-dimethylacrylamide) block (PDMAc = block A) and a hydrophobic poly(diacetone acrylamide) block (PDAAm = block B). Such BAB copolymers tend to form bridged micelles/networks, which was expected to make the PISA process much more complex than for conventional diblock copolymers. Kinetic monitoring, light scattering analyses and macroscopic observations allowed identifying crucial parameters that influence the polymerization and the final dispersion properties, notably the stirring of the polymerization medium, the macroRAFT agent concentration, its ionization degree (related to the pH) and its Z group alkyl chain length.
    Mots-clés : POLE 4, POLYMERES.
    Pièce jointe Full Text PDF 2.7 Mo (source)

  • A. Cartier, E. Levernier, A. - L. Dhimane, T. Fukuyama, C. Ollivier, I. Ryu, et L. Fensterbank, « Synthesis of Aliphatic Amides through a Photoredox Catalyzed Radical Carbonylation Involving Organosilicates as Alkyl Radical Precursors », Advanced Synthesis & Catalysis, vol. 362, nᵒ 11, p. 2254-2259, 2020.
    Résumé : Alkyl radicals, from primary to tertiary, formed by photocatalyzed oxidation of organosilicates, are involved efficiently in radical carbonylation with carbon monoxide (CO), in the presence of various amines and CCl4, leading to a variety of amides in moderate to good yields.
    Mots-clés : Carbonylation, MACO, multi-component reaction, photooxidative catalysis, POLE 1, radical/polar, silicates.
    Pièce jointe Full Text PDF 4.8 Mo (source)

  • M. S. Centellas, M. Piot, R. Salles, A. Proust, L. Tortech, D. Brouri, S. Hupin, B. Abécassis, D. Landy, C. Bo, et G. Izzet, « Exploring the self-assembly of dumbbell-shaped polyoxometalate hybrids, from molecular building units to nanostructured soft materials », Chemical Science, vol. 11, nᵒ 40, p. 11072-11080, oct. 2020.
    Résumé : The formation of hierarchical nanostructures using preformed dumbbell-like species made of covalent organic–inorganic polyoxometalate (POM)-based hybrids is herein described. In this system, the presence of charged subunits (POM, metal linkers, and counter ions) in the complex molecular architecture can drive their aggregation, which results from a competition between the solvation energy of the discrete species and intermolecular electrostatic interactions. We show that the nature of the POM and the charge of the metal linker are key parameters for the hierarchical nanoorganization. The experimental findings were corroborated with a computational investigation combining DFT and molecular dynamics simulation methods, which outlines the importance of solvation of the counter ion and POM/counter ion association in the aggregation process. The dumbbell-like species can also form gels, in the presence of a poorer solvent, displaying similar nanoorganization of the aggregates. We show that starting from the designed molecular building units whose internal charges can be controlled by redox trigger we can achieve their implementation into soft nanostructured materials through the control of their supramolecular organization.
    Mots-clés : E-POM, POLE 2.
    Pièce jointe Snapshot 798 ko (source)
    Pièce jointe Full Text PDF 943.8 ko (source)

  • F. Coumes, M. Balarezo, J. Rieger, et F. Stoffelbach, « Biobased Amphiphilic Block Copolymers by RAFT-Mediated PISA in Green Solvent », Macromolecular Rapid Communications, vol. 41, nᵒ 9, p. 2000002, 2020.
    Résumé : Biobased amphiphilic diblock copolymers are prepared thanks to the combination of reversible addition–fragmentation transfer (RAFT) polymerization and polymerization-induced self-assembly (PISA) in an eco-friendly solvent mixture. First, the formation of a poly(acrylic acid) macroRAFT agent (PAA-TTC) is performed in water at 70 °C. Then, in a series of experiments, the PAA-TTC macroRAFT agent is used directly, without purification, as both chain transfer agent and stabilizing agent in the RAFT-PISA of menthyl acrylate (MnA) in dispersion in an ethanol/water mixture. The polymerizations of MnA are fast with high final conversions and well-controlled amphiphilic diblock copolymers are synthesized. Stable, sub-micrometric spherical particles composed of the diblock copolymers are formed. The influence of the monomer concentration and the length of the solvophobic block on the diameter of the self-assemblies is studied by means of dynamic light scattering and cryogenic transmission electron-microscopy.
    Mots-clés : amphiphilic copolymers, biobased monomers, dispersion polymerization, PISA, POLE 4, POLYMERES, RAFT.
    Pièce jointe Full Text PDF 1.3 Mo (source)

  • L. Cunningham, Y. Wang, C. Nottingham, J. Pagsulingan, G. Jaouen, M. McGlinchey, et P. J. Guiry, « Enantioselective Synthesis of Planar Chiral Ferrocifens that Show Chiral Discrimination in Antiproliferative Activity on Breast Cancer Cells », ChemBioChem, vol. 21, nᵒ 20, p. 2974-2981, 2020.
    Résumé : The design and first enantioselective synthesis of a series of chiral ferrocifens and ferrociphenols was realised via enantioselective palladium-catalysed intramolecular direct C?H bond activation followed by McMurry coupling. Biological evaluation revealed moderate anticancer activities on breast cancer cells and evidence of chiral discrimination between enantiomers. Treatment of these novel ferrocifens with Ag 2 O revealed that these systems are unable to form a neutral quinone methide, yet still demonstrate marked antiproliferative properties versus both the hormone-dependent MCF-7 and hormone-independent MDA-MB-231 cell lines. This bioactivity arises from two mechanisms: Fenton-type chemistry and the anti-estrogenic activity associated with the tamoxifen-like structure.
    Mots-clés : anti-cancer activity, asymmetric synthesis, CHEMBIO, Ferrocene, McMurry coupling, POLE 3.
    Note Note
    <p>doi: 10.1002/cbic.202000311</p>

  • F. D'Agosto, J. Rieger, et M. Lansalot, « RAFT-Mediated Polymerization-Induced Self-Assembly », Angewandte Chemie International Edition, vol. 59, nᵒ 22, p. 8368-8392, 2020.
    Résumé : After a brief history that positions polymerization-induced self-assembly (PISA) in the field of polymer chemistry, this Review will cover the fundamentals of the PISA mechanism. Furthermore, this Review will also give an overview of some of the features and limitations of RAFT-mediated PISA in terms of the choice of the components involved, the nature of the nanoobjects that can be obtained and how the syntheses can be controlled, as well as some potential applications.
    Mots-clés : block copolymers, heterogeneous polymerization, morphology, PISA, POLE 4, POLYMERES, RAFT.
    Pièce jointe Full Text PDF 4.4 Mo (source)

  • A. Delvaux, E. Rathahao‐Paris, et S. Alves, « An emerging powerful technique for distinguishing isomers: Trapped Ion Mobility Spectrometry ‐ Time‐of‐Flight Mass Spectrometry for a rapid characterization of estrogen isomers », Rapid Communications in Mass Spectrometry, août 2020.

  • S. Dhifaoui, M. Hajji, T. Guerfel, V. Marvaud, J. - C. Daran, I. Turowska-Tyrk, R. Bel-Hadj-Tahar, et H. Nasri, « Experimental and computational studies on the structure and properties of a novel low-spin iron(III) macrocyclic complex », Molecular Crystals and Liquid Crystals, vol. 702, nᵒ 1, p. 92-109, mai 2020.
  • B. Doistau, L. Benda, J. - L. Cantin, O. Cador, F. Pointillart, W. Wernsdorfer, L. - M. Chamoreau, V. Marvaud, B. Hasenknopf, et G. Vives, « Dual switchable molecular tweezers incorporating anisotropic MnIII–salphen complexes », Dalton Transactions, vol. 49, nᵒ 26, p. 8872-8882, juill. 2020.
    Résumé : An alternative strategy for the synthesis of terpyridine based switchable molecular tweezers has been developed to incorporate anisotropic Mn(III)–salphen complexes. The free ligand was synthesized using a building block strategy based on Sonogashira coupling reactions and was then selectively metalated with manganese in a last step. The conformation of the tweezers was switched from an open ‘W’ shaped form to a closed ‘U’ form by Zn(II) coordination to the terpyridine unit bringing the two Mn–salphen moieties in close spatial proximity as confirmed by X-ray crystallography. An alternate switching mechanism was observed by the intercalation of a bridging cyanide ligand between the two Mn–salphen moieties that resulted in the closing of the tweezers. These dual stimuli are attractive for achieving multiple controls of the mechanical motion of the tweezers. A crystallographic structure of unexpected partially oxidized closed tweezers was also obtained. One of the two Mn–salphen moieties underwent a ligand-centered oxidation of an imino to an amido group allowing an intramolecular Mn–Oamide–Mn linkage. The magnetic properties of the manganese(III) dimers were investigated to evaluate the magnetic exchange interaction and analyze the single molecule magnet behavior.
    Mots-clés : E-POM, GOBS, POLE 2, POLE 3.
    Pièce jointe Snapshot 876.4 ko (source)
    Pièce jointe Full Text PDF 4.2 Mo (source)

  • H. Dossmann, D. Gatineau, H. Clavier, A. Memboeuf, D. Lesage, et Y. Gimbert, « Exploring Phosphine Electronic Effects on Molybdenum Complexes: A Combined Photoelectron Spectroscopy and Energy Decomposition Analysis Study », The Journal of Physical Chemistry A, p. acs.jpca.0c06746, oct. 2020.

  • H. Du, F. A. de Oliveira, L. J. C. Albuquerque, G. Tresset, E. Pavlova, C. Huin, P. Guégan, et F. C. Giacomelli, « Polyglycidol-Stabilized Nanoparticles as a Promising Alternative to Nanoparticle PEGylation: Polymer Synthesis and Protein Fouling Considerations », Langmuir, vol. 36, nᵒ 5, p. 1266-1278, févr. 2020.
    Résumé : We herein demonstrate the outstanding protein-repelling characteristic of star-like micelles and polymersomes manufactured from amphiphilic block copolymers made by poly(butylene oxide) (PBO) hydrophobic segments and polyglycidol (PGL) hydrophilic outer shells. Although positively charged proteins (herein modeled by lysozyme) may adsorb onto the surface of micelles and polymersomes where the assemblies are stabilized by short PGL chains (degree of polymerization smaller than 15), the protein adsorption vanishes when the degree of polymerization of the hydrophilic segment (PGL) is higher than ∼20, regardless the morphology. This has been probed by using three different model proteins which are remarkably different concerning molecular weight, size, and zeta potential (bovine serum albumin (BSA), lysozyme, and immunoglobulin G (IgG)). Indeed, the adsorption of the most abundant plasma protein (herein modeled as BSA) is circumvented even by using very short PGL shells due to the highly negative zeta potential of the produced assemblies which presumably promote protein–nanoparticle electrostatic repulsion. The negative zeta potential, on the other hand, enables lysozyme adsorption, and the phenomenon is governed by electrostatic forces as evidenced by isothermal titration calorimetry. Nevertheless, the protein coating can be circumvented by slightly increasing the degree of polymerization of the hydrophilic segment. Notably, the PGL length required to circumvent protein fouling is significantly smaller than the one required for PEO. This feature and the safety concerns regarding the synthetic procedures on the preparation of poly(ethylene oxide)-based amphiphilic copolymers might make polyglycidol a promising alternative toward the production of nonfouling spherical particles.
    Mots-clés : POLE 4, POLYMERES.
    Pièce jointe Full Text PDF 4.1 Mo (source)

  • L. El Khoury, F. Célerse, L. Lagardère, L. - H. Jolly, E. Derat, Z. Hobaika, R. G. Maroun, P. Ren, S. Bouaziz, N. Gresh, et J. - P. Piquemal, « Reconciling NMR Structures of the HIV-1 Nucleocapsid Protein NCp7 Using Extensive Polarizable Force Field Free-Energy Simulations », Journal of Chemical Theory and Computation, vol. 16, nᵒ 4, p. 2013-2020, avr. 2020.
    Résumé : Using polarizable (AMOEBA) and nonpolarizable (CHARMM) force fields, we compare the relative free energy stability of two extreme conformations of the HIV-1 nucleocapsid protein NCp7 that had been previously experimentally advocated to prevail in solution. Using accelerated sampling techniques, we show that they differ in stability by no more than 0.75–1.9 kcal/mol depending on the reference protein sequence. While the extended form appears to be the most probable structure, both forms should thus coexist in water explaining the differing NMR findings.
    Mots-clés : MACO, POLE 1.
    Pièce jointe Full Text PDF 1.7 Mo (source)

  • R. El-Hnayn, L. Canabady-Rochelle, C. Desmarets, L. Balan, H. Rinnert, O. Joubert, G. Medjahdi, H. Ben Ouada, et R. Schneider, « One-Step Synthesis of Diamine-Functionalized Graphene Quantum Dots from Graphene Oxide and Their Chelating and Antioxidant Activities », Nanomaterials, vol. 10, nᵒ 1, p. 104, janv. 2020.
    Résumé : 2,2&rsquo;-(Ethylenedioxy)bis(ethylamine)-functionalized graphene quantum dots (GQDs) were prepared under mild conditions from graphene oxide (GO) via oxidative fragmentation. The as-prepared GQDs have an average diameter of ca. 4 nm, possess good colloidal stability, and emit strong green-yellow light with a photoluminescence (PL) quantum yield of 22% upon excitation at 375 nm. We also demonstrated that the GQDs exhibit high photostability and the PL intensity is poorly affected while tuning the pH from 1 to 8. Finally, GQDs can be used to chelate Fe(II) and Cu(II) cations, scavenge radicals, and reduce Fe(III) into Fe(II). These chelating and reducing properties that associate to the low cytotoxicity of GQDs show that these nanoparticles are of high interest as antioxidants for health applications.
    Mots-clés : 2, 2’-(ethylenedioxy)bis(ethylamine), ARC, graphene quantum dots, optical properties, POLE 1, redox-active nanoparticles.
    Pièce jointe Full Text PDF 3.9 Mo (source)

  • G. Falco, L. Simonin, S. Pensec, F. Dalmas, J. - M. Chenal, L. Bouteiller, et L. Chazeau, « Linear and nonlinear viscoelastic properties of segmented silicone-urea copolymers: Influence of the hard segment structure », Polymer, vol. 186, p. 122041, janv. 2020.
    Résumé : The linear and non-linear viscoelastic behaviors of 5 segmented silicone copolymers - with low fraction of 1,6-hexamethylene diisocyanate (HDI), 4,4′-methylenebis (cyclohexyl isocyanate) (HMDI), 1,3-bis(1-isocyanato-1-methylethyl)benzene (TMXDI), 2,4-tolylene diisocyanate (TDI) or isophorone diisocyanate (IPDI) as hard segments (HS) - are compared, in relation with their microstructure. When the HS are non-symmetrical, the materials nanostructuration is weak and has a limited impact on the mechanical response: two mechanical relaxations occur after the α relaxation of the polydimethylsiloxane (PDMS), the first related to the “unfreezing” of the HS-HS bonds, and the second one to the sticky reptation of the polymer chains. Conversely, when the HS are symmetrical, their self-organization is favored and the long range ordering of the HS is possible. The materials are then semi-crystalline like, with a low crystallinity (due to the low weight percentage of HS) and their flow, possible above their melting temperature (Tm), depends also on the HS dynamics, which is the most rapid for HDI.
    Mots-clés : Mechanical relaxations, Nanostructure, POLE 4, POLYMERES, Segmented copolymers.

  • 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.
    Pièce jointe Snapshot 604.1 ko (source)
    Pièce jointe Full Text PDF 3.9 Mo (source)

  • 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.

  • 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.
    Pièce jointe Full Text PDF 6.8 Mo (source)

  • 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.

  • 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.
    Pièce jointe Full Text PDF 5.5 Mo (source)

  • 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.
    Mots-clés : CSOB, 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.

0 | 50 | 100 | 150 | 200 | 250 | 300 | 350 | 400 | ... | 1150

--- Exporter la sélection au format