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  • F. Abbassi, M. Mbarek, D. Kreher, et K. Alimi, « Synthesis and characterization of a copolymer involving PVK and MEH-PPV for organic electronic devices », Journal of Physics and Chemistry of Solids, vol. 103, p. 142-146.
    Résumé : A statistic copolymer denoted (PVK)x-(MEH-PPV)y containing poly(N-vinylcarbazole) (PVK) as well as poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) building blocks was prepared by chemical oxidative way. Correlations structure-properties of the synthesized copolymer were investigated by using different experimental analyses (IR, XRD, ATG, optical absorption, PL and PLRT) combined with theoretical calculations (DFT). The new copolymer exhibits interesting properties compared to PVK and MEH-PPV homopolymers taken separately. The resulting copolymer has improved thermal stability and it exhibits original optical properties compared to the PVK and MEH-PPV ones as well as its reveled charge transfer process and the continuous donor acceptor existence. All these experimental and theoretical analysis argue the originality of this new material which could then be exploited in optoelectronics.
    Mots-clés : A. Polymers, B. Chemical synthesis, C. Ab initio calculations, C. Optical properties, POLE 4, POLYMERES.

  • R. Albigès, P. Klein, S. Roi, F. Stoffelbach, C. Creton, L. Bouteiller, et J. Rieger, « Water-based acrylic coatings reinforced by PISA-derived fibers », Polymer Chemistry.
    Résumé : Polymerization-induced self-assembly (PISA) is an efficient approach to synthesize self-assembled core–shell nanofibers in water, made of amphiphilic block copolymers. We demonstrate here for the first time that such anisotropic and high Tg nanofibers can be used as reinforcing fillers for water-based acrylic materials. This strategy opens the way for strong all-organic aqueous coatings.
    Mots-clés : POLE 4, POLYMERES.
    Pièce jointe Full Text PDF 407.3 ko (source)

  • S. P. Babailov, E. V. Peresypkina, Y. Journaux, et K. E. Vostrikova, « Nickel(II) complex of a biradical: Structure, magnetic properties, high NMR temperature sensitivity and moderately fast molecular dynamics », Sensors and Actuators B: Chemical, vol. 239, p. 405-412.

  • P. Barbier Saint Hilaire, A. Warnet, Y. Gimbert, U. M. Hohenester, G. Giorgi, M. - F. Olivier, F. Fenaille, B. Colsch, C. Junot, et J. - C. Tabet, « Mechanistic study of competitive releases of H2O, NH3 and CO2 from deprotonated aspartic and glutamic acids: Role of conformation », Journal of Chromatography B, vol. 1047, p. 64-74.
    Résumé : The aims of this study were to highlight the impact of minor structural differences (e.g. an aminoacid side chain enlargement by one methylene group), on ion dissociation under collision-induced dissociation conditions, and to determine the underlying chemical mechanisms. Therefore, we compared fragmentations of deprotonated aspartic and glutamic acids generated in negative electrospray ionization. Energy-resolved mass spectrometry breakdown curves were recorded and MS3 experiments performed on an Orbitrap Fusion for high-resolution and high-mass accuracy measurements. Activated fragmentations were performed using both the resonant and non-resonant excitation modes (i.e., CID and HCD, respectively) in order to get complementary information on the competitive and consecutive dissociative pathways. These experiments showed a specific loss of ammonia from the activated aspartate but not from the activated glutamate. We mainly focused on this specific observed loss from aspartate. Two different mechanisms based on intramolecular reactions (similar to those occurring in organic chemistry) were proposed, such as intramolecular elimination (i.e. Ei-like) and nucleophilic substitution (i.e. SNi-like) reactions, respectively, yielding anions as fumarate and α lactone from a particular conformation with the lowest steric hindrance (i.e. with antiperiplanar carboxyl groups). The detected deaminated aspartate anion can then release CO2 as observed in the MS3 experimental spectra. However, quantum calculations did not indicate the formation of such a deaminated aspartate product ion without loss of carbon dioxide. Actually, calculations displayed the double neutral (NH3+CO2) loss as a concomitant pathway (from a particular conformation) with relative high activation energy instead of a consecutive process. This disagreement is apparent since the concomitant pathway may be changed into consecutive dissociations according to the collision energy i.e., at higher collision energy and at lower excitation conditions, respectively. The latter takes place by stabilization of the deaminated aspartate solvated with two residual molecules of water (present in the collision cell). This desolvated anion formed is an α lactone substituted by a methylene carboxylate group. The vibrational excitation acquired by [(D−H)−NH3]−during its isolation is enough to allow its prompt decarboxylation with a barrier lower than 8.4 kJ/mol. In addition, study of glutamic acid-like diastereomers constituted by a cyclopropane, hindering any side chain rotation, confirms the impact of the three-dimensional geometry on fragmentation pathways. A significant specific loss of water is only observed for one of these diastereomers. Other experiments, such as stable isotope labeling, need to be performed to elucidate all the observed losses from activated aspartate and glutamate anions. These first mechanistic interpretations enhance understanding of this dissociative pathway and underline the necessity of studying fragmentation of a large number of various compounds to implement properly new algorithms for de novo elucidation of unknown metabolites.
    Mots-clés : CSOB, Electrospray high-resolution mass spectrometry, POLE 3, Regioselective dissociation, Unexpected cleavage of aspartate anion.

  • R. Beaud, R. K. Nandi, A. Perez-Luna, R. Guillot, D. Gori, C. Kouklovsky, N. - E. Ghermani, V. Gandon, et G. Vincent, « Revealing the electrophilicity of N-Ac indoles with FeCl3: a mechanistic study », Chemical Communications, vol. 53, nᵒ 43, p. 5834-5837.
    Résumé : Herein, we report a mechanistic exploration of the unusual FeCl3-mediated hydroarylation of N-Ac indoles. Electron density topology analysis of a crystal, in situ IR monitoring, Hammett and Taft studies as well as DFT computations allowed us to determine that activation of acetyl with FeCl3 and of the C2C3 bond with a proton is involved.
    Mots-clés : POLE 1, ROCS.

  • M. Beaupérin, D. Polat, F. Roudesly, S. Top, A. Vessières, J. Oble, G. Jaouen, et G. Poli, « Approach to ferrocenyl-podophyllotoxin analogs and their evaluation as anti-tumor agents », Journal of Organometallic Chemistry, vol. 839, p. 83-90.
    Résumé : Podophyllotoxin is a natural product endowed of a high antimitotic activity and a high affinity for tubulin. Its action results in the cessation of cell division, inducing cell death. However, its high toxicity restrains its use as drug. To overcome this drawback, several chemical modifications of the native podophyllotoxin have been made. However, to date, no reports have so far been directed toward incorporation of a metallocene moiety. The search for new organometallic drugs is a central field in drug discovery, including the domain of cancer therapy. In particular, metallocenyl moieties are known to increase or decrease, depending on the degree of conjugation in the organometallic motif, the selectivity of drugs toward cancer cells. The conjugate organometallic compound reduces the damage of healthy tissues, yet permitting the selective desired antimitotic and cytotoxic effects of the active principle. We report here the synthesis of ferrocene-containing podophyllotoxin analogs and preliminary antiproliferative tests.
    Mots-clés : Antitumor agent, Bioorganometallic chemistry, CHEMBIO, Ferrocene, Multi-step synthesis, Palladium, Podophyllotoxin, POLE 1, POLE 3, ROCS.

  • J. Blass, J. Brunke, F. Emmerich, C. Przybylski, V. M. Garamus, A. Feoktystov, R. Bennewitz, G. Wenz, et M. Albrecht, « Interactions between shape-persistent macromolecules as probed by AFM », Beilstein Journal of Organic Chemistry, vol. 13, p. 938-951.

  • V. N. Bochatay, L. Debien, F. Chemla, F. Ferreira, O. Jackowski, et A. Perez-Luna, « Synthesis of allenylzinc reagents by 1,2-rearrangement of alkynyl(disilyl)zincates derived from acetylenic epoxides and acetylenic aziridines », Comptes Rendus Chimie, vol. 20, nᵒ 6, p. 609-616.
    Résumé : Lithium alkynyl(disilyl)zincates obtained from metalated ethynyloxiranes, as well as from N-tert-butanesulfinyl(ethynyl)aziridines or N-tert-butanesulfonyl(ethynyl)aziridines, undergo 1,2-migration of the organosilyl group with ring opening of the oxirane or aziridine ring by SNi displacement. A developed protocol that involves nBuLi for the metalation step offers a straightforward approach to the corresponding δ-oxy- and

    δ-amino α-silyl allenylzinc intermediates. The reagents derived from the epoxides are amenable to subsequent in situ condensation with aldehydes or ketones to provide 1,3-diols but not those derived from aziridines that only react sluggishly in similar condensations.
    Mots-clés : alkynes, carbenoids, POLE 1, rearrangement, ROCS, silicon, Zinc.

  • T. Borelli, S. Brenna, G. Broggini, J. Oble, et G. Poli, « (Diacyloxyiodo)benzenes-Driven Palladium-Catalyzed Cyclizations of Unsaturated N-Sulfonylamides: Opportunities of Path Selection », Advanced Synthesis & Catalysis, vol. 359, nᵒ 4, p. 623-628.
    Résumé : A study of the palladium(II)-catalyzed cyclization of unsaturated N-sulfonylamides was undertaken, using (diacyloxyiodo)benzenes as terminal oxidizing agents. Different reactivities were observed as a function of the nature of the unsaturation (terminal vs. internal), or of the hypervalent iodine compound used (diacetoxyiodobenzene vs. bistrifluoroacetoxyiodobenzene). Proper parameter selection allows the direction of the cyclization to be chosen towards either a global aminoacetoxylation, an allylic amination via aminopalladation, or an allylic amination via allylic C–H activation.
    Mots-clés : allylic compounds, amination, C–H activation, homogeneous catalysis, Palladium, POLE 1, ROCS.

  • G. Bouhalleb, O. Mhasni, G. Poli, et F. Rezgui, « Direct palladium-catalyzed allylic alkylations of alcohols with enamines: Synthesis of homoallyl ketones », Tetrahedron Letters, vol. 58, p. 2525-2529.
    Résumé : An efficient, direct nucleophilic allylic substitution of α-, β- and γ-substituted alcohols with enamines, using the Pd(OAc)2/PPh3 catalyst system and ZnBr2 as a promoter in CH2Cl2 at reflux, is reported. The reaction course was dependent on the steric hindrance at the α- or γ-positions with respect to the functionalized α-carbon, selectively affording in moderate to good yields, α- or γ-homoallyl ketones, the so-called “linear” and “branched” products, respectively.
    Mots-clés : Allylic alcohol, Allylic substitution, Enamine, Homoallyl ketone, Palladium, POLE 1, ROCS.

  • L. Chang, K. Plevová, S. Thorimbert, et L. Dechoux, « Preparation of Substituted 2H-Pyrans via a Cascade Reaction from Methyl Coumalate and Activated Methylene Nucleophiles », The Journal of Organic Chemistry, vol. 82, nᵒ 10, p. 5499-5505.
    Résumé : The reaction of methyl coumalate with a wide range of methylene active compounds, such as keto-esters or keto-sulfones and cyclic or acyclic diketones, afforded more than 30 2,3,5,6-tetrasubstituted 2H-pyrans. The reaction proceeds via a cascade reaction involving a Michael addition-6π-electrocyclic ring opening-proton transfer and 6π electrocyclization, in which a variety of functional groups were tolerated.
    Mots-clés : CHEMBIO, POLE 3.

  • M. Chenal, C. Véchambre, J. - M. Chenal, L. Chazeau, V. Humblot, L. Bouteiller, C. Creton, et J. Rieger, « Mechanical properties of nanostructured films with an ultralow volume fraction of hard phase », Polymer, vol. 109, p. 187-196.
    Résumé : We demonstrate in this paper how polymerization induced self-assembly (PISA) using RAFT can be used to synthesize very asymmetric but monodisperse poly(acrylic acid)-b-poly(n-butyl acrylate) block copolymers, PAA-b-PBA, with a short PAA block and a long PBA block. In the course of the surfactant-free emulsion polymerization, core-shell particles form in water, with the short hydrophilic block located at the water-particle interface, and the long hydrophobic block constituting the particle core. Drying at room temperature creates films possessing an out of equilibrium structure, where the glassy PAA block generates a percolating network of shells. When deformed in uniaxial elongation, these films combine a high stiffness in small strains (considering the low volume fraction of PAA, of only 3 wt%), a yield stress and a significant extensibility before failure. The modulus, yield stress and extensibility can be tuned by modifying the composition of the latex serum with cations or positively charged low molar mass polymers, or by changing the copolymer composition. Of particular interest was the synthesis by PISA of particles of triblock copolymer PAA-b-PBA-b-PS. The out of equilibrium structure obtained had a very interesting combination of high stiffness, extensibility and high fracture toughness.
    Mots-clés : Core-shell latexes, Film, Mechanical properties, Nanostructure, POLE 4, POLYMERES, RAFT polymerization.

  • A. Conte-Daban, V. Borghesani, S. Sayen, E. Guillon, Y. Journaux, G. Gontard, L. Lisnard, et C. Hureau, « Link between Affinity and Cu(II) Binding Sites to Amyloid-β Peptides Evaluated by a New Water-Soluble UV–Visible Ratiometric Dye with a Moderate Cu(II) Affinity », Analytical Chemistry, vol. 89, nᵒ 3, p. 2155-2162.
    Résumé : Being able to easily determine the Cu(II) affinity for biomolecules of moderate affinity is important. Such biomolecules include amyloidogenic peptides, such as the well-known amyloid-β peptide involved in Alzheimer’s disease. Here, we report the synthesis of a new water-soluble ratiometric Cu(II) dye with a moderate affinity (109 M–1 at pH 7.1) and the characterizations of the Cu(II) corresponding complex by X-ray crystallography, EPR, and XAS spectroscopic methods. UV–vis competition was performed on the Aβ peptide as well as on a wide series of modified peptides, leading to an affinity value of 1.6 × 109 M–1 at pH 7.1 for the Aβ peptide and to a coordination model for the Cu(II) site within the Aβ peptide that agrees with the one mostly accepted currently.
    Mots-clés : ERMMES, POLE 2.

  • M. Courté, M. Alaaeddine, V. Barth, L. Tortech, et D. Fichou, « Structural and electronic properties of 2,2′,6,6′-tetraphenyl-dipyranylidene and its use as a hole-collecting interfacial layer in organic solar cells », Dyes and Pigments, vol. 141, p. 487-492.
    Résumé : The accumulation of positive charges at the anodic interface considerably limits the efficiency of photovoltaic solar cells based on polymer/fullerene bulk heterojunctions (BHJs). Interfacial layers (IFLs) such as PEDOT:PSS improve charge injection but have no effect on the unbalanced electron/hole transport across the BHJ. We report here the use of 2,2′,6,6′-tetraphenyl-dipyranylidene (DIPO-Ph4), a planar quinoïd compound, as an efficient anodic IFL in organic solar cells based on BHJs made of poly(3-hexylthiophene)/[6,6]-phenyl-C61-butyric-acid-methyl-ester (P3HT:PCBM). When deposited under vacuum onto a glass substrate, DIPO-Ph4 thin films are constituted of densely packed and vertically aligned crystalline needles. Current-sensing atomic force microscopy (CS-AFM) reveals a considerable increase of the hole-carrying pathways in DIPO-Ph4 thin films as compare to PEDOT:PSS, thus revealing their hole transporting/electron blocking properties. Inserting a 10 nm thick IFL of DIPO-Ph4 in combination with a 5 nm thick PEDOT:PSS between the ITO electrode and the P3HT:PCBM film leads to photocurrent densities up to 11.5 mA/cm2 under AM 1.5G and conversion efficiencies up to 4.6%, that is substantially higher than PEDOT:PSS-only devices.
    Mots-clés : atomic force microscopy, Bulk heterojunction, Hole collection, Interfacial layers, NASCO, Organic solar cells, POLE 2.

  • M. Courté, S. G. Surya, R. Thamankar, C. Shen, V. R. Rao, S. G. Mhailsalkar, et D. Fichou, « A non-volatile resistive memory effect in 2,2′,6,6′-tetraphenyl-dipyranylidene thin films as observed in field-effect transistors and by conductive atomic force microscopy », RSC Advances, vol. 7, nᵒ 6, p. 3336-3342.
    Résumé : The charge transport properties of 2,2′,6,6′-tetraphenyldipyranylidene (DIPO-Ph4), a large planar quinoïd π-conjugated heterocycle, are investigated in field-effect transistor (FET) configuration and by conductive atomic force microscopy (c-AFM). The FET properties show a clear p-type behavior with a hole mobility up to 2 × 10−2 cm2 V−1 s−1 and on/off ratio of 104. The transfer characteristics Id/Vg present a clear hysteresis typical of a resistive memory effect. This memory effect is again observed by means of c-AFM in lateral mode using a nearby gold top-contact as the counter-electrode. The c-AFM current response recorded for variable distances d = 0.5–9.0 μm between the AFM tip and the top electrode shows a resistive switching behavior in the low-voltage 0.0–3.0 V region. Repeated “write-read-erase-read” cycles performed at low frequency reveal a non-volatile memory effe

    ct in the form of high-resistance and low-resistance states with a stable on/off ratio of 102 during cycling operation.
    Mots-clés : NASCO, POLE 2.
    Pièce jointe Full Text PDF 1009.9 ko (source)

  • E. Darii, S. Alves, Y. Gimbert, A. Perret, et J. - C. Tabet, « Meaning and consequence of the coexistence of competitive hydrogen bond/salt forms on the dissociation orientation of non-covalent complexes », Journal of Chromatography B, vol. 1047, p. 45-58.
    Résumé : Non-covalent complexes (NCC) between hexose monophosphates (HexP) and arginine (R) were analyzed using ESI MS and MS/MS in negative mode under different (hard, HC and soft, SC) desolvation conditions. High resolution mass spectrometry (HRMS) revealed the presence of different ionic species, namely, homo- and heteromultimers of R and HexP. Deprotonated heterodimers and corresponding sodiated species were enhanced under HC likely due to a decrease in available charge number associated with the reduction of H+/Na+ exchange. The quantum calculations showed that the formation of covalent systems is very little exothermic, therefore, such systems are disfavored. Desolvation dependent CID spectra of deprotonated [(HexP+R)‒H]− complexes demonstrated that they can exist within the hydrogen bond (HB) and salt bridge (SB) forms, yielding either NCC separation or covalent bond cleavages, respectively. Although HB forms are the main species, they cannot survive under HC; therefore, the minor SB forms became detectable. Energy-resolved mass spectrometry (ERMS) experiments revealed diagnostic fragment ions from both SB and HB forms, providing evidence that these isomeric forms are inconvertible. SB formation should result from the ionic interactions of highly acidic group of HexP with strongly basic guanidine group of arginine and thus requires an arginine zwitterion (ZW) form. This was confirmed by quantum calculations. Ion-ion interactions are significantly affected by the presence of sodium cation as demonstrated by the fragmentation patterns of sodiated complex species. Regarding CID data, only SB between protonated amino group of R and deprotonated phosphate group of HexP could be suggested, but the primary amine is not enough basic then, the SB must be fleeting. Nevertheless, the observation of the covalent bond cleavages suggests the presence of structures with a free negative charge able to induce fragmentations. Indeed, according to quantum calculations, solvated salt (SS) systems involving Na+/COO− salt solvated by neutral phosphate and negative charge on sugar ring are preferentially formed.
    Mots-clés : CSOB, POLE 3.

  • B. Doistau, L. Benda, J. - L. Cantin, L. - M. Chamoreau, E. Ruiz, V. Marvaud, B. Hasenknopf, et G. Vives, « Six states switching of redox-active molecular tweezers by three orthogonal stimuli », Journal of the American Chemical Society.
    Résumé : A six level molecular switch based on terpyridine(Ni-salphen)2 tweezers and addressable by three orthogonal stimuli (metal coordination, redox reaction and guest binding) is reported. By a metal coordination stimulus, the tweezers can be mechanically switched from an open “W”-shaped conformation to a closed “U”-shaped form. Theses two states can each be reversibly oxidized by the redox stimulus and bind to a pyrazine guest resulting in four additional states. All six states are stable and accessible by the right combination of stimuli and were studied by NMR, XRD, EPR spectroscopy and DFT calculations. The combination of the supramolecular concepts of mechanical motion and guest binding with the redox non-innocent and valence tautomerism properties of Ni-salphen complexes added two new dimensions to a mechanical switch.
    Mots-clés : E-POM, GOBS, POLE 2, POLE 3.

  • M. Dréan, A. Debuigne, C. Goncalves, C. Jérôme, P. Midoux, J. Rieger, et P. Guégan, « Use of Primary and Secondary Polyvinylamines for Efficient Gene Transfection », Biomacromolecules, vol. 18, nᵒ 2, p. 440-451.
    Résumé : Gene transfection with polymeric carrier remains a challenge; particularly, high transfection levels combined with low toxicity are hard to achieve. We herein revisit polyvinylamines, an old and neglected family of cationic polymers. They can be readily obtained by controlled hydrolysis of polyvinylamides prepared through (controlled) radical polymerization. A series of tailor-made and well-defined polyvinylamines bearing primary amino groups, and poly(N-methylvinylamine) bearing secondary amines, were evaluated for the transfection of cells with pDNA as a function of their molar mass, molar mass distribution, and degree of deacetylation. Unexpected high transfection levels, in combination with low cytotoxicity were recorded for both series. Surprisingly, a great impact of the molar mass was observed for the primary amine polyvinylamine series, whereas the results were mostly independent of molar mass or dispersity for the polymer bearing secondary amine. It was further established that a certain percentage of acetamide groups increased the transfection level, while maintaining low cytotoxicity. These results highlight for the first time the real potential of polyvinylamines as gene carriers, and make these polymers very attractive for further development in gene therapy.
    Mots-clés : POLE 4, POLYMERES.

  • T. Driant, F. Nachon, C. Ollivier, P. - Y. Renard, et E. Derat, « On the Influence of the Protonation States of Active Site Residues on AChE Reactivation: A QM/MM Approach », ChemBioChem, vol. 18, nᵒ 7, p. 666-675.
    Résumé : Acetylcholinesterase (AChE), an enzyme of the serine hydrolase superfamily, is a mediator of signal transmission at cholinergic synapses by catalyzing acetylcholine cleavage into acetate and choline. This enzyme is vulnerable to covalent inhibition by organophosphate compounds (like VX). Covalent inhibition of AChE does not revert spontaneously. Known reactivator compounds have limited action in restoring catalytic activity. QM/MM simulations of VX-inhibited AChE reactivation by pralidoxime (2-PAM), a classical reactivator, were performed. These afforded a broad view of the effect of protonation states of active-site residues, and provide evidence for the role of Glu202, which needs to be protonated for reactivation to occur. In situ deprotonation of 2-PAM for both protonation states of Glu202 showed that His447 is able to deprotonate 2-PAM with the assistance of Glu202. Because the active site of serine hydrolases is highly conserved, this work provides new insights on the interplay between the catalytic triad residues and this glutamate, newly identified as protonatable.
    Mots-clés : acetylcholinesterase, Computational chemistry, MACO, organophosphate, POLE 1, protonation, QM/MM, reactivation.

  • L. Ferrand, Y. Lyu, A. Rivera-Hernández, B. J. Fallon, M. Amatore, C. Aubert, et M. Petit, « Hydroboration and Diboration of Internal Alkynes Catalyzed by a Well-Defined Low-Valent Cobalt Catalyst », Synthesis.
    Résumé : Thieme E-Books & E-Journals
    Mots-clés : MACO, POLE 1.

  • L. Ferrand, Y. Tang, C. Aubert, L. Fensterbank, V. Mouriès-Mansuy, M. Petit, et M. Amatore, « Niobium-Catalyzed Intramolecular Addition of O–H and N–H Bonds to Alkenes: A Tool for Hydrofunctionalization », Organic Letters, vol. 19, nᵒ 8, p. 2062-2065.
    Résumé : A convenient, versatile, and easy to handle intramolecular hydrofunctionalization of alkenes (C–O and C–N bonds formation) is reported using a novel niobium-based catalytic system. This atom economic and eco-friendly methodology provides an additional synthetic tool for the straightforward formation of valuable building blocks enabling molecular complexity. Various pyran, furan, pyrrolidine, piperidine, lactone, and lactam derivatives as well as spirocyclic compounds are produced in high yields and selectivities.
    Mots-clés : MACO, POLE 1.

  • A. Flambard, A. Sugahara, S. De, M. Okubo, A. Yamada, et R. Lescouëzec, « Probing the local structure of Prussian blue electrodes by 113Cd NMR spectroscopy », Dalton Transactions, vol. 46, nᵒ 19, p. 6159-6162.
    Résumé : We demonstrate that 113Cd NMR is a potent technique to monitor the local electronic and structural states of the Prussian blue electrode during Li+ intercalation, providing an atomic-scale insight into the reaction mechanism.
    Mots-clés : ERMMES, POLE 2.

  • C. Fopp, K. Isaac, E. Romain, F. Chemla, F. Ferreira, O. Jackowski, M. Oestreich, et A. Perez-Luna, « Stereodivergent Synthesis of β-Heteroatom-Substituted Vinyl­silanes by Sequential Silylzincation–Copper(I)-Mediated Electrophilic­ Substitution », Synthesis, vol. 49, nᵒ 04, p. 724-735.
    Résumé : Thieme E-Books & E-Journals
    Mots-clés : POLE 1, ROCS.

  • J. W. Fredy, J. Scelle, G. Ramniceanu, B. - T. Doan, C. S. Bonnet, É. Tóth, M. Ménand, M. Sollogoub, G. Vives, et B. Hasenknopf, « Mechanostereoselective One-Pot Synthesis of Functionalized Head-to-Head Cyclodextrin [3]Rotaxanes and Their Application as Magnetic Resonance Imaging Contrast Agents », Organic Letters, vol. 19, nᵒ 5, p. 1136-1139.
    Mots-clés : GOBS.
    Note Note
    <p>doi: 10.1021/acs.orglett.7b00153</p>

  • M. Fumagalli, K. Belal, H. Guo, F. Stoffelbach, G. Cooke, A. Marcellan, P. Woisel, et D. Hourdet, « Supramolecular polymer hydrogels induced by host–guest interactions with di-[cyclobis(paraquat-p-phenylene)] cross-linkers: from molecular complexation to viscoelastic properties », Soft Matter, vol. 13, nᵒ 31, p. 5269-5282.
    Résumé : Supramolecular polymer networks have been designed on the basis of a π-electron donor/acceptor complex: naphthalene (N)/cyclobis(paraquat-p-phenylene) (CBPQT4+ = B). For this purpose, a copolymer of N,N-dimethylacrylamide P(DMA-N1), lightly decorated with 1 mol% of naphthalene pendant groups, has been studied in semi-dilute un-entangled solution in the presence of di-CBPQT4+ (BB) crosslinker type molecules. While calorimetric experiments demonstrate the quantitative binding between N and B groups up to 60 °C, the introduction of BB crosslinkers into the polymer solution gives rise to gel formation above the overlap concentration. From a comprehensive investigation of viscoelastic properties, performed at different concentrations, host/guest stoichiometric ratios and temperatures, the supramolecular hydrogels are shown to follow a Maxwellian behavior with a strong correlation of the plateau modulus and the relaxation time with the effective amount of interchain cross-linkers and their dissociation dynamics, respectively. The calculation of the dissociation rate constant of the supramolecular complex, by extrapolation of the relaxation time of the network back to the beginning of the gel regime, is discussed in the framework of theoretical and experimental works on associating polymers.
    Mots-clés : POLE 4, POLYMERES.
    Pièce jointe Full Text PDF 2.9 Mo (source)

  • G. A. Garcia, H. Dossmann, L. Nahon, S. Daly, et I. Powis, « Identifying and Understanding Strong Vibronic Interaction Effects Observed in the Asymmetry of Chiral Molecule Photoelectron Angular Distributions », ChemPhysChem, vol. 18, nᵒ 5, p. 500-512.
    Résumé : Electron–ion coincidence imaging is used to study chiral asymmetry in the angular distribution of electrons emitted from randomly-oriented enantiomers of two molecules, methyloxirane and trifluoromethyloxirane, upon ionization by circularly polarized VUV synchrotron radiation. Vibrationally-resolved photoelectron circular dichroism (PECD) measurements of the outermost orbital ionization reveal unanticipated large fluctuations in the magnitude of the forward–backward electron scattering asymmetry, including even a complete reversal of direction. Identification and assignment of the vibrational excitations is supported by Franck–Condon simulations of the photoelectron spectra. A previously proposed quasi-diatomic model for PECD is developed and extended to treat polyatomic systems. The parametric dependence of the electronic dipole matrix elements on nuclear geometry is evaluated in the adiabatic approximation. It provokes vibrational level dependent shifts in amplitude and phase, to which the chiral photoelectron angular distributions are especially sensitive. It is shown that single quantum excitation of those vibrational modes, which experience only a relatively small displacement of the ion equilibrium geometry along the normal coordinate and which are then only weakly excited in the Franck–Condon limit, can be accompanied by big shifts in scattering phase; hence the observed big fluctuations in PECD asymmetry for such modes.
    Mots-clés : circular dichroism, CSOB, photoelectron circular dichroism, photoelectron spectroscopy, photoionization, Photophysics, POLE 3.

  • D. Gatineau, A. Memboeuf, A. Milet, R. B. Cole, H. Dossmann, Y. Gimbert, et D. Lesage, « Experimental bond dissociation energies of benzylpyridinium thermometer ions determined by threshold-CID and RRKM modeling », International Journal of Mass Spectrometry.

  • M. N. Godoi, F. de Azambuja, P. D. G. Martinez, N. H. Morgon, V. G. Santos, T. Regiani, D. Lesage, H. Dossmann, R. B. Cole, M. N. Eberlin, et C. R. D. Correia, « Revisiting the Intermolecular Fujiwara Hydroarylation of Alkynes », European Journal of Organic Chemistry, vol. 2017, nᵒ 13, p. 1794-1803.

  • C. Gonçalves, J. - P. Gomez, W. Même, B. Rasolonjatovo, D. Gosset, S. Nedellec, P. Hulin, C. Huin, T. Le Gall, T. Montier, P. Lehn, C. Pichon, P. Guégan, H. Cheradame, et P. Midoux, « Curcumin/poly(2-methyl-2-oxazoline-b-tetrahydrofuran-b-2-methyl-2-oxazoline) formulation: An improved penetration and biological effect of curcumin in F508del-CFTR cell lines », European Journal of Pharmaceutics and Biopharmaceutics, vol. 117, p. 168-181.
    Résumé : Neutral amphiphilic triblock ABA copolymers are of great interest to solubilize hydrophobic drugs. We reported that a triblock ABA copolymer consisting of methyl-2-oxazoline (MeOx) and tetrahydrofuran (THF) (MeOx6-THF19-MeOx6) (TBCP2) can solubilize curcumin (Cur) a very hydrophobic molecule exhibiting multiple therapeutic effects but whose insolubility and low stability in water is a major drawback for clinical applications. Here, we provide evidences by flow cytometry and confocal microscopy that Cur penetration in normal and ΔF508-CFTR human airway epithelial cell lines is facilitated by TBCP2. When used on ΔF508-CFTR cell lines, the Cur/TBCP2 formulation promotes the restoration of the expression of the CFTR protein in the plasma membrane. Furthermore, patch-clamp and MQAE fluorescence experiments show that this effect is associated with a correction of a Cl− selective current at the membrane surface of F508del-CFTR cells. The results show the great potential of the neutral amphiphilic triblock copolymer MeOx6-THF19-MeOx6 as carrier for curcumin in a Cystic Fibrosis context. We anticipate that other MeOxn-THFm-MeOxn copolymers could have similar behaviours for other highly insoluble therapeutic drugs or cosmetic active ingredients.
    Mots-clés : Amphiphilic polymer, CFTR, Curcumin, Cystic fibrosis, POLE 4, POLYMERES, Triblock copolymer.

  • M. Gormen, P. Pigeon, Y. Wang, A. Vessières, S. Top, F. Martial, C. Gros, M. J. McGlinchey, et G. Jaouen, « Side-Chain Effects on the 1-(Bis-aryl-methylidene)-[3]ferrocenophane Skeleton: Antiproliferative Activity against TNBC Cancer Cells and Comparison with the Acyclic Ferrocifen Series », European Journal of Inorganic Chemistry, vol. 2017, nᵒ 2, p. 454-465.
    Résumé : As part of our ongoing study of the toxicity of compounds derived from 1,1-bis(4-hydroxyphenyl)-2-ferrocenylbut-1-ene, we have recently shown that closely analogous [3]ferrocenophane complexes have an in vitro toxicity level substantially higher than that of their ferrocene counterparts, particularly in the case of mono- and diphenol complexes. In this study we have examined whether the presence of a dimethylamino chain, analogous to the chain in hydroxytamoxifen, is capable of producing in the ferrocenophane series the same antiestrogenic effect observed for OH-Tam and Fc-OH-Tam. To this end, we have synthesized and characterized new complexes bearing various side-chains [O(CH2)3NMe2, O(CH2)3piperidine, O(CH2)3pyrrolidine, NHCO(CH2)2NMe2] and studied the biochemical properties of those complexes possessing appropriate solubility. The results revealed that the new complexes of [3]ferrocenophane have very strong antiproliferative effe

    cts; one of the compounds bearing an NHCO(CH2)2NMe2 chain has an IC50 value of 0.05 ± 0.02 µm for MDA-MB-231 breast cancer cells. All the complexes showed affinity for the estradiol receptor. At the low (nanomolar range) concentrations at which the estrogenic/antiestrogenic effect is expressed in these molecules, the presence of an amino-substituted side-chain does not induce in the [3]ferrocenophane series the antiestrogenic effect observed with OH-Tam and Fc-OH-Tam. However, this effect has been found for the complex with a slightly longer chain [O(CH2)4NMe2].
    Mots-clés : Antitumor agents, Bioorganometallic chemistry, CHEMBIO, Ferrocene, POLE 3, substituent effects, Toxicity.

  • B. Habchi, S. Alves, D. J. - R. Bouveresse, B. Moslah, A. Paris, Y. Lécluse, P. Gauduchon, P. Lebailly, D. N. Rutledge, et E. Rathahao-Paris, « An innovative chemometric method for processing direct introduction high resolution mass spectrometry metabolomic data: independent component–discriminant analysis (IC–DA) », Metabolomics, vol. 13, nᵒ 4, p. 45.
    Résumé : IntroductionTo perform large scale metabolomic analyses, high throughput approaches are required. The direct introduction mass spectrometry (DIMS) approach appears to be very attractive to achieve this goal. However, processing DIMS data is still very challenging due to the large number of samples and the intrinsic complexity of the mass spectra.ObjectivesThe objective of this study is to develop a computational procedure, based on an innovative chemometric method, i.e. Independent component–discriminant analysis (IC–DA), for processing DIMS data.MethodMetabolomic fingerprints were obtained by direct introduction high resolution mass spectrometry (DI-HRMS) analysis of urine samples of subjects that had been professionally exposed to pesticides. Spectral data were processed using the developed IC–DA procedure. Results obtained from this method were compared to those obtained by the conventional Partial least squares–discriminant analysis (PLS–DA). For both the IC–DA and PLS–DA methods, a validation was performed based on a permutation test.ResultIC–DA results enabled a good detection of discriminant variables and a clear discrimination of control samples and exposure classes whereas a less striking discrimination was obtained with PLS–DA. Putative annotation of these variables was performed using metabolomic databases. Targeted correlation analysis was used for the detection of ions associated with the most discriminant variables, consolidating their identity assignment.ConclusionThis study demonstrated the efficiency of IC–DA to discriminate the different exposure groups. As well the improvement of high throughput metabolomic studies was provided by combining DI–HRMS with this new chemometric tool.
    Mots-clés : CSOB, POLE 3.

  • L. Hassouna, N. Illy, et P. Guégan, « Phosphazene/triisobutylaluminum-promoted anionic ring-opening polymerization of 1,2-epoxybutane initiated by secondary carbamates », Polymer Chemistry, vol. 8, nᵒ 27, p. 4005-4013.
    Résumé : Attempts to use a carbamate-phosphazene base as the initiating system for the polymerization of 1,2-epoxybutane was unsuccessful. As a matter of fact, carbamate deprotonation by phosphazene bases led to their fast decomposition generating alkoxide anions which initiate the polymerization rather than carbamate anions. Conversely, in the presence of triisobutylaluminum – a Lewis acid – the in situ generation of an anionic initiator X− obtained by the deprotonation of the tBuP4 phosphazene base was tested as a possible way to initiate the polymerization of 1,2-epoxybutane. Particular attention was given to the detection of eventual transfer or side-reactions according to the carbamate:triisobutylaluminum:phosphazene base ratio, to the solvent dielectric constant and to the number of PN– units in the phosphazene base. The reaction was performed with a stoichiometric ratio (1:1:1) of carbamate:triisobutylaluminum:tBuP2, which gave the best results. Under these conditions, the initiation of the polymerization by the carbamate anion was quantitative; no transfer reactions have been observed and the polymerization proceeded in a controlled manner to afford amide end-capped poly(butylene oxide) with a narrow molar mass distribution and expected molar masses.
    Mots-clés : POLE 4, POLYMERES.
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  • G. Izzet, F. Volatron, et A. Proust, « Tailor–made Covalent Organic-Inorganic Polyoxometalate Hybrids: Versatile Platforms for the Elaboration of Functional Molecular Architectures », The Chemical Record, vol. 17, nᵒ 2, p. 250-266.
    Résumé : Post-functionalization of organically modified polyoxometalates (POMs) is a powerful synthetic tool to devise functional building blocks for the rational elaboration of POM-based molecular materials. In this personal account we focus on iodoaryl-terminated POM platforms, describe reliable routes to the synthesis of covalent organic-inorganic POM-based hybrids and their integration into advanced molecular architectures or multi-scale assemblies as well as their immobilization onto surfaces. Valorisation of the remarkable redox properties of POMs in the fields of artificial synthesis and molecular electronic is especially considered.
    Mots-clés : artificial photosynthesis, E-POM, modified electrodes, organic-inorganic hybrids, palladium cross-coupling, POLE 2, Polyoxometalates.

  • L. Le Falher, A. Mumtaz, A. Nina Diogo, S. Thorimbert, et C. Botuha, « Chemoselective Access to π-Conjugated Heterocycles by Stille and Sonogashira Reactions on 2-Substituted 4H-Pyrido[e][1,3]oxazin-4-ones », European Journal of Organic Chemistry, vol. 2017, nᵒ 4, p. 827-832.
    Résumé : Site-selective PdII-catalyzed cross-coupling reactions of 2-substituted-4H-pyrido[e][1,3]oxazin-4-ones were developed. C4- and C5-alkynylated pyridooxazinones were thus obtained through Sonogashira coupling, whereas the efficient incorporation of (hetero)aryl and ethenyl substituents at the C5 position was achieved by Stille coupling. Finally, an example of one-pot sequential multiple Sonogashira reactions with different alkynes was realized. The strategy developed herein provides rapid access to polyfunctionalized precursors with extended π-conjugation for further application as fluorescent materials.
    Mots-clés : CHEMBIO, cross-coupling, Fluorescent probes, heterocycles, homogeneous catalysis, Palladium, POLE 3.
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  • K. J. Lee, Y. Xiao, J. H. Woo, E. Kim, D. Kreher, A. - J. Attias, F. Mathevet, J. - C. Ribierre, J. W. Wu, et P. André, « Charge-transfer dynamics and nonlocal dielectric permittivity tuned with metamaterial structures as solvent analogues », Nature Materials, vol. advance online publication.
    Résumé : Charge transfer (CT) is a fundamental and ubiquitous mechanism in biology, physics and chemistry. Here, we evidence that CT dynamics can be altered by multi-layered hyperbolic metamaterial (HMM) substrates. Taking triphenylene:perylene diimide dyad supramolecular self-assemblies as a model system, we reveal longer-lived CT states in the presence of HMM structures, with both charge separation and recombination characteristic times increased by factors of 2.4 and 1.7—that is, relative variations of 140 and 73%, respectively. To rationalize these experimental results in terms of driving force, we successfully introduce image dipole interactions in Marcus theory. The non-local effect herein demonstrated is directly linked to the number of metal–dielectric pairs, can be formalized in the dielectric permittivity, and is presented as a solid analogue to local solvent polarity effects. This model and extra PH3T:PC60BM results show the generality of this non-local phenomenon and that a wide range of kinetic tailoring opportunities can arise from substrate engineering. This work paves the way toward the design of artificial substrates to control CT dynamics of interest for applications in optoelectronics and chemistry.
    Mots-clés : Metamaterials, POLE 4, POLYMERES, Structural properties, Ultrafast photonics.

  • C. Lévêque, V. Corcé, L. Chenneberg, C. Ollivier, et L. Fensterbank, « Photoredox/Nickel Dual Catalysis for the C(sp3)–C(sp3) Cross-Coupling of Alkylsilicates with Alkyl Halides », European Journal of Organic Chemistry, vol. 2017, nᵒ 15, p. 2118-2121.
    Résumé : Alkylsilicates were engaged under photoredox/nickel dual catalysis conditions with alkyl halides for the first time. The C(sp3)–C(sp3) cross-coupling products were obtained in moderate yields and were accompanied by the homocoupling products of the alkyl halide derivatives. These promising findings are strongly suggestive of the high synthetic potential of the dual catalytic approach for the forging of alkyl carbon–carbon bonds.
    Mots-clés : cross-coupling, C–C coupling, MACO, Nickel, photoredox catalysis, POLE 1, radical reactions.

  • J. Malinge, B. Géraudie, P. Savel, V. Nataf, A. Prignon, C. Provost, Y. Zhang, P. Ou, K. Kerrou, J. - N. Talbot, J. - M. Siaugue, M. Sollogoub, et C. Ménager, « Liposomes for PET and MR Imaging and for Dual Targeting (Magnetic Field/Glucose Moiety): Synthesis, Properties, and in Vivo Studies », Molecular Pharmaceutics, vol. 14, nᵒ 2, p. 406-414.
    Résumé : We describe the potentiality of a new liposomal formulation enabling positron emission tomography (PET) and magnetic resonance MR imaging. The bimodality is achieved by coupling a 68Ga-based radiotracer on the bilayer of magnetic liposomes. In order to enhance the targeting properties obtained under a permanent magnetic field, a sugar moiety was added in the lipid formulation. Two new phospholipids were synthesized, one with a specific chelator of 68Ga (DSPE-PEG-NODAGA) and one with a glucose moiety (DSPE-PEG-glucose). The liposomes were produced according to a fast and safe process, with a high radiolabeling yield. MR and PET imaging were performed on mice bearing human glioblastoma tumors (U87MG) after iv injection. The accumulation of the liposomes in solid tumor is evidenced by MR imaging and the amount is evaluated in vivo and ex vivo according to PET imaging. An efficient magnetic targeting is achieved with these new magnetic liposomes.
    Mots-clés : GOBS, POLE 3.

  • M. Mon, J. Ferrando-Soria, M. Verdaguer, C. Train, C. Paillard, B. Dkhil, C. Versace, R. Bruno, D. Armentano, et E. Pardo, « Postsynthetic Approach for the Rational Design of Chiral Ferroelectric Metal-Organic Frameworks », Journal of the American Chemical Society, vol. 139, nᵒ 24, p. 8098-8101.
    Résumé : Ferroelectrics (FEs) are materials of paramount importance with a wide diversity of applications. Herein, we propose a postsynthetic methodology for the smart implementation of ferroelectricity in chiral metal organic frameworks (MOFs): following a single crystal to single-crystal cation metathesis, the Ca2+ counterions of a preformed chiral MOF of formula Ca-6(II){C-24(II)[(S,S)-hismox](12) (OHO2)}center dot 212H(2)O ( 1), where hismox is a chiral ligand derived from the natural amino acid L-histidine, are replaced by CH3NH3+. The resulting compound, (CH3NH3)(12){Cu-24(II)[(S,S)-hiSMOX](12)(OH2)(3)}center dot 178H(2)O (2), retains the polar space group of 1 and is ferroelectric below 260 K. These results open a new synthetic avenue to enlarge the limited number of FE MOFs.
    Mots-clés : behavior, crystals, HorsPole, multiferroics, polarization.

  • J. Moussa, A. Loch, L. - M. Chamoreau, A. Degli Esposti, E. Bandini, A. Barbieri, et H. Amouri, « Luminescent Cyclometalated Platinum Complexes with π-Bonded Catecholate Organometallic Ligands », Inorganic Chemistry, vol. 56, nᵒ 4, p. 2050-2059.
    Résumé : A series of cyclometalated platinum(II) complexes of the type [(ppy)Pt(LM)]n+ (n = 0, 1) with π-bonded catecholates acting as organometallic ligands (LM) have been prepared and characterized by analytical techniques. In addition, the structures of two complexes of the series were determined by single-crystal X-ray diffraction. The packing shows the formation of a 1D supramolecular assembly generated by dPt–πCp* interactions among individual units. All complexes are luminescent in the solid state and in solution media. The results of photophysics have been rationalized by means of density functional theory (DFT) and time-dependent DFT investigations.
    Mots-clés : ARC, POLE 1.

  • S. B. Moussa, H. Bachouâ, M. Gruselle, P. Beaunier, A. Flambard, et B. Badraoui, « Hybrid organic-inorganic materials based on hydroxyapatite structure », Journal of Solid State Chemistry, vol. 248, p. 171-177.
    Résumé : The present article details the formation of calcium hydroxyapatite synthesized by the hydrothermal way, in presence of glycine or sarcosine. The presence of these amino-acids during the synthetic processes reduces the crystalline growthing through the formation of hybrid organic-inorganic species The crystallite sizes are decreasing and the morphology is modified with the increase of the amino-acid concentration.
    Mots-clés : ARC, ERMMES, Glycine, Hydrothermal synthesis, Hydroxyapatite, POLE 1, POLE 2, Sarcosine.

  • C. K. O'Sullivan, M. Ortiz, A. , M. Debela, M. Svobodova, S. Thorimbert, D. Lesage, R. Cole, et B. Hasenknopf, « PCR Incorporation of Polyoxometalate Modified Deoxynucleotide Triphosphates and Their Application in Molecular Electrochemical Sensing of Yersinia pestis », Chemistry – A European Journal, vol. 23, nᵒ 44, p. 10597–10603.
    Résumé : Redox-labeled nucleotides are of increasing interest for the fabrication of next generation molecular tools and should meet requirements of being thermally stable, sensitive, and compatible with polymerase-mediated incorporation whilst also being electrochemically discriminable. The synthesis and characterization of Keggin and Dawson polyoxometalate-deoxynucleotide (POM-dNTP) bioconjugates linked through 7-deaza-modified purines is described. The modified POM-dNTPs were used for polymerase based amplification of a DNA sequence specific for Yersinia pestis and the amplified DNA detected via an electrochemical DNA sensor. This highlights the potential of polyoxometalates as thermally stable, sensitive and polymerase-compatible redox labels for exploitation in bioanalytical applications.
    Mots-clés : Biosensor, CHEMBIO, CSOB, Electroanalytical Chemistry, GOBS, Labelled nucleotides, PCR, POLE 3, Polyoxometalates.
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  • A. Parrot, A. Bernard, A. Jacquart, S. A. Serapian, C. Bo, E. Derat, O. Oms, A. Dolbecq, A. Proust, R. Métivier, P. Mialane, et G. Izzet, « Photochromism and Dual-Color Fluorescence in a Polyoxometalate–Benzospiropyran Molecular Switch », Angewandte Chemie International Edition, vol. 56, nᵒ 17, p. 4872-4876.
    Résumé : The photophysical properties of a Keggin-type polyoxometalate (POM) covalently bounded to a benzospiropyran (BSPR) unit have been investigated. These studies reveal that both closed and open forms are emissive with distinct spectral features (λem (closed form)=530 nm, λem (open form)=670 nm) and that the fluorescence of the BSPR unit of the hybrid is considerably enhanced compared to BSPR parent compounds. While the fluorescence excitation energy of the BSPR reference compounds (370 nm) is close to the intense absorption responsible of the photochromic character (350 nm), the fluorescence excitation of the hybrid is shifted to lower energy (400 nm), improving the population of the emissive state. Combined NOESY NMR and theoretical calculations of the closed form of the hybrid give an intimate understanding of the conformation adopted by the hybrid and show that the nitroaryl moieties of the BSPR is folded toward the POM, which should affect the electronic properties of the BSPR.
    Mots-clés : density functional calculations, E-POM, fluorescence, MACO, molecular photoswitches, photochromism, POLE 1, POLE 2, Polyoxometalates.

  • M. Petricevic, L. F. Sobala, P. Z. Fernandes, L. Raich, A. J. Thompson, G. Bernardo-Seisdedos, O. Millet, S. Zhu, M. Sollogoub, J. Jiménez-Barbero, C. Rovira, G. J. Davies, et S. J. Williams, « Contribution of Shape and Charge to the Inhibition of a Family GH99 endo-α-1,2-Mannanase », Journal of the American Chemical Society, vol. 139, nᵒ 3, p. 1089-1097.
    Résumé : Inhibitor design incorporating features of the reaction coordinate and transition-state structure has emerged as a powerful approach for the development of enzyme inhibitors. Such inhibitors find use as mechanistic probes, chemical biology tools, and therapeutics. Endo-α-1,2-mannosidases and endo-α-1,2-mannanases, members of glycoside hydrolase family 99 (GH99), are interesting targets for inhibitor development as they play key roles in N-glycan maturation and microbiotal yeast mannan degradation, respectively. These enzymes are proposed to act via a 1,2-anhydrosugar “epoxide” mechanism that proceeds through an unusual conformational itinerary. Here, we explore how shape and charge contribute to binding of diverse inhibitors of these enzymes. We report the synthesis of neutral dideoxy, glucal and cyclohexenyl disaccharide inhibitors, their binding to GH99 endo-α-1,2-mannanases, and their structural analysis by X-ray crystallography. Quantum mechanical calculations of the free energy landscapes reveal how the neutral inhibitors provide shape but not charge mimicry of the proposed intermediate and transition state structures. Building upon the knowledge of shape and charge contributions to inhibition of family GH99 enzymes, we design and synthesize α-Man-1,3-noeuromycin, which is revealed to be the most potent inhibitor (KD 13 nM for Bacteroides xylanisolvens GH99 enzyme) of these enzymes yet reported. This work reveals how shape and charge mimicry of transition state features can enable the rational design of potent inhibitors.
    Mots-clés : GOBS, POLE 3.

  • C. Pezzetta, L. F. Veiros, J. Oble, et G. Poli, « Murai Reaction on Furfural Derivatives Enabled by Removable N,N′-Bidentate Directing Groups », Chemistry - A European Journal, vol. 23, p. 8385-8389.
    Résumé : Furfural and related compounds are industrially relevant building blocks obtained from lignocellulosic biomass. To enhance the added value of these renewable resources, a Ru-catalyzed hydrofurylation of alkenes, involving a directed C−H activation at C3 of the furan ring, was developed. A thorough experimental study revealed that a bidentate amino-imine directing group enabled the des

    ired coupling. Removal of the directing group occurred during the purification step, directly releasing the C3-functionalized furfurals. Development of the reaction as well as optimization and scope of the method were described. A mechanism was proposed on the basis of DFT calculations.
    Mots-clés : aldimines, alkenes, C−H activation, furfural, POLE 1, ROCS, Ruthenium.

  • L. Pocquet, N. Vologdin, G. F. Mangiatordi, I. Ciofini, O. Nicolotti, S. Thorimbert, et M. Salmain, « Supramolecular Anchoring of NCN-Pincer Palladium Complexes into a β-Barrel Protein Host: Molecular-Docking and Reactivity Insights », European Journal of Inorganic Chemistry, vol. 2017, nᵒ 30, p. 3622-3634.
    Résumé : Several prochiral NCN-pincer complexes of palladium(II), with hemilabile ligands and a long aliphatic chain, were synthesized and characterized spectroscopically. In some of the complexes, the presence of two different substituents on the N donor atoms made them stereogenic, so that they were isolated as a mixture of diastereoisomers, which could be differentiated by 1H NMR spectroscopy. Binding of some of these complexes to bovine β-lactoglobin by insertion within its inner cavity was theoretically investigated by molecular-docking simulations and was experimentally confirmed by CD spectroscopy. Adjunction of H-bond donor substituents on the ligand framework gave more-stable supramolecular protein–complex assemblies. These constructs were shown to catalyze aldol condensation reactions in aqueous media, affording, in some cases, the less-favorable cis product. Since the corresponding complexes exclusively gave the trans product in the absence of β-lactoglobulin, this unusual diastereoselectivity was ensued by the second sphere of coordination brought by the protein host.
    Mots-clés : Aldol reactions, CHEMBIO, Docking, Metalloenzymes, Palladium, β-Lactoglobulin.

  • A. Pontes da Costa, D. R. Nunes, M. Tharaud, J. Oble, G. Poli, et J. Rieger, « Palladium(0) Nanoparticles Embedded in Core–shell Nanogels as Recoverable Catalysts for the Mizoroki–Heck Reaction », ChemCatChem, vol. 9, nᵒ 12, p. 2167-2175.
    Résumé : Core–shell nanogels are attractive stabilizers and supports for catalytically active metallic nanoparticles. Herein, we present the synthesis and the characterization of a nanostructured well-defined core–shell nanogel with the ability to stabilize Pd0 nanoparticles in its core. This hybrid nanogel displays a remarkable stability in both the solid state and in solution. This feature allowed its successful application as a catalyst for the Mizoroki–Heck reaction between n-butyl acrylate and a series of bromo- and iodoarenes. The yields spanned from good to excellent, and catalyst recycling could be achieved up to three times without a significant activity loss. Three-phase tests indicated that the hybrid nanogel acts as a Pd0 nanoreservoir. The catalysis proceeds in a quasihomogeneous fashion as part of the catalytic activity occurs outside the nanogel, which explains the observed limited recyclability.
    Mots-clés : C−C coupling, immobilization, Palladium, POLE 1, POLE 4, POLYMERES, RAFT polymerization, ROCS, supported catalysts.
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  • B. Rasolonjatovo, B. Pitard, T. Haudebourg, V. Bennevault, et P. Guégan, « Synthesis of tetraarm star block copolymer based on polytetrahydrofuran and poly(2-methyl-2-oxazoline) for gene delivery applications », European Polymer Journal, vol. 88, p. 689-700.
    Résumé : New star shaped block copolymers were synthesized according to a core first strategy, with a hydrophobic polytetrahydrofuran (PTHF) central block and a poly(2-methyl-2-oxazoline) (PMeOx) external block. First, the cationic polymerization of THF was initiated from a tetrafunctional triflate ester synthesized in situ. The chain ends were functionalized by quenching the polymerization with an excess of MeOx, that allowed for the MeOx polymerization under microwave in a subsequent step. Demonstration of the expected structures was carried out at each step of the polymerization. The controlled molar mass of the star copolymers was kept below 5000 g mol−1 in order to mimick the structure of the efficient poloxamines for gene transfer applications. Formulations containing various concentrations of star block copolymers were intramuscularly injected in mice. Efficient gene transfer was measured at formulations with very low concentration of copolymer compared to reference standard containing Lutrol®.
    Mots-clés : CROP, Gene therapy, POLE 4, Poly(2-methyl-2-oxazoline), POLYMERES.

  • E. Rathahao-Paris, S. Alves, L. Debrauwer, J. - P. Cravedi, et A. Paris, « An efficient data-filtering strategy for easy metabolite detection from the direct analysis of a biological fluid using Fourier transform mass spectrometry », Rapid Communications in Mass Spectrometry, vol. 31, nᵒ 6, p. 485-494.
    Résumé : Rationale High-throughput analyses require an overall analytical workflow including not only a robust and high-speed technical platform, but also dedicated data-processing tools able to extract the relevant information. This work aimed at evaluating post-acquisition data-mining tools for selective extraction of metabolite species from direct introduction high-resolution mass spectrometry data. Methods Investigations were performed on spectral data in which seven metabolites of vinclozolin, a dicarboximide fungicide containing two chloride atoms, were previously manually identified. The spectral data obtained from direct introduction (DI) and high-resolution mass spectrometry (HRMS) detection were post-processed by plotting the mass defect profiles and applying various data-filtering methods based on accurate mass values. Results Exploration of mass defect profiles highlighted, in a specific plotting region, the presence of compounds containing common chemical elements and pairs of conjugated and non-conjugated metabolites resulting from classical metabolic pathways. Additionally, the judicious application of mass defect and/or isotope pattern filters removed many interfering ions from DI-HRMS data, greatly facilitating the detection of vinclozolin metabolites. Compared with previous results obtained by manual data treatment, three additional metabolites of vinclozolin were detected and putatively annotated. Conclusions Tracking simultaneously several specific species could be efficiently performed using data-mining tools based on accurate mass values. The selectivity of the data extraction was improved when the isotope filter was used for halogenated compounds, facilitating metabolite ion detection even for low-abundance species. Copyright © 2016 John Wiley & Sons, Ltd.
    Mots-clés : CSOB, POLE 3.

  • T. S. Rodrigues, D. Lesage, W. A. da Silva, R. B. Cole, G. Ebeling, J. Dupont, H. C. B. de Oliveira, M. N. Eberlin, et B. A. D. Neto, « Charge-tagged N-heterocyclic carbenes (NHC): Direct transfer from ionic liquid solutions and long-lived nature in the gas phase », Journal of The American Society for Mass Spectrometry, vol. 28, nᵒ 6, p. 1021-1029.

  • F. Roudesly, J. Oble, et G. Poli, « Metal-catalyzed CH activation/functionalization: The fundamentals », Journal of Molecular Catalysis A: Chemical, vol. 426, Part B, p. 275-296.
    Résumé : An isolated CH bond in a molecule has a very low reactivity owing to the large kinetic barrier associated to the CH bond cleavage and the apolar nature of this bond. For this reason, the selective reactivity of such a non-functional group is under active study since several decades and is still regarded as the Holy Grail in chemistry. Metal-catalyzed CH activation/functionalization chemistry allows the step-economical and original construction of CC as well as CO and CN bonds starting from hydrocarbons (or hydrocarbon fragments) without the need of prior non catalytic oxidation steps. Furthermore, it can be of utmost importance in the domain of multistep syntheses, and also in transformations of societal significance such as the conversion of methane into methanol. This tutorial review addresses to students and researchers who would like to become acquainted with this fascinating topic. After a brief historical introduction, the main mechanistic fundaments of metal-catalyzed CH activation are exposed. Then, a selection of seminal advances and conceptual breakthroughs are presented.
    Mots-clés : C-heteroatom bond formation, CC bond formation, CH activation, CH functionalization, Mechanistic study, POLE 1, ROCS.

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