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  • Y. Si, C. Grazon, G. Clavier, J. Rieger, Y. Tian, J. - F. Audibert, B. Sclavi, et R. Méallet-Renault, « Fluorescent Copolymers for Bacterial Bioimaging and Viability Detection », ACS Sensors, vol. 5, nᵒ 9, p. 2843-2851, sept. 2020.
    Résumé : Novel fluorescent labels with high photostability and high biocompatibility are required for microbiological imaging and detection. Here, we present a green fluorescent polymer chain (GFPC), designed to be nontoxic and water-soluble, for multicolor bioimaging and real-time bacterial viability determination. The copolymer is synthesized using a straightforward one-pot reversible addition–fragmentation chain-transfer (RAFT) polymerization technique. We show that GFPC does not influence bacterial growth and is stable for several hours in a complex growth medium and in the presence of bacteria. GFPC allows the labeling of the bacterial cytoplasm for multicolor bacterial bioimaging applications. It can be used in combination with propidium iodide (PI) to develop a rapid and reliable protocol to distinguish and quantify, in real time, by flow cytometry, live and dead bacteria.
    Mots-clés : POLE 4, POLYMERES.
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  • L. F. Sobala, G. Speciale, S. Zhu, L. Raich, N. Sannikova, A. J. Thompson, Z. Hakki, D. Lu, S. Shamsi Kazem Abadi, A. R. Lewis, V. Rojas-Cervellera, G. Bernardo-Seisdedos, Y. Zhang, O. Millet, J. Jiménez-Barbero, A. J. Bennet, M. Sollogoub, C. Rovira, G. J. Davies, et S. J. Williams, « An Epoxide Intermediate in Glycosidase Catalysis », ACS Central Science, vol. 6, nᵒ 5, p. 760-770, mai 2020.

  • A. Sodreau, A. Vivien, A. Moisset, C. Salzemann, C. Petit, et M. Petit, « Simpler and Cleaner Synthesis of Variously Capped Cobalt Nanocrystals Applied in the Semihydrogenation of Alkynes », Inorganic Chemistry, vol. 59, nᵒ 19, p. 13972-13978, oct. 2020.
    Résumé : Unlike the classical organometallic approach, we report here a synthetic pathway requiring no reducing sources or heating to produce homogeneous hexagonal-close-packed cobalt nanocrystals (Co NCs). Involving a disproportionation process, this simple and fast (6 min) synthesis is performed at room temperature in the presence of ecofriendly fatty alcohols to passivate Co NCs. Through a recycling step, the yield of Co NCs is improved and the waste generation is limited, making this synthetic route cleaner. After an easy exchange of the capping ligands, we applied them as unsupported catalysts in the stereoselective semihydrogenation of alkynes.
    Mots-clés : MACO, POLE 1.
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  • A. Solé-Daura, T. Zhang, H. Fouilloux, C. Robert, C. M. Thomas, L. - M. Chamoreau, J. J. Carbó, A. Proust, G. Guillemot, et J. M. Poblet, « Catalyst Design for Alkene Epoxidation by Molecular Analogues of Heterogeneous Titanium-Silicalite Catalysts », ACS Catalysis, vol. 10, nᵒ 8, p. 4737-4750, avr. 2020.
    Résumé : The epoxidation of allylic alcohols with H2O2 catalyzed by the hybrid [α-B-SbW9O33(tBuSiO)3Ti(OiPr)]3– (1) anion as a molecular model of heterogeneous Ti-silicalite TS-1 catalyst was analyzed by means of DFT to determine the main factors that control the catalytic process and, finally, to improve the value of the available catalysts. Our calculations revealed that unlike other alkenes, allylic alcohols can bind the Ti center after activation of the precatalyst via hydrolysis to give the corresponding Ti-alcoholate, which is the catalyst resting state. Next, the dissociative addition of hydrogen peroxide to Ti causes the cleavage of a Ti–OSi junction to form a Ti(η2-OOH) moiety. The partial detachment of the Ti from the catalyst structure yields an intermediate with a flexible Ti center from which the Ti-OOH group can transfer an electrophilic oxygen to the alkene substrate in an inner-sphere fashion. The rate-determining process, which involves the heterolytic activation of H2O2 over the Ti(IV) and the electrophilic O-transfer, accounts for an overall free-energy barrier of 23.0 kcal mol–1 for 2-methyl-2-buten-1-ol, in line with the experimental value of 22.3. Conversely, the outer-sphere O-transfer—also accessible to nonfunctionalized alkenes—occurs through a more strained transition state that lays above in energy (by ∼4 kcal mol–1), giving a clue to explain the low yields reported experimentally for nonfunctionalized olefins. We also found that reducing the bulkiness of the substituents in the silanol functions of the catalyst has a positive influence on the catalytic activity, decreasing the overall free-energy barriers for the outer-sphere path. With this knowledge, we developed other catalytic species with tailored steric properties based on [SbW9O33(RSiOH)3]3– structure (R =iPr and nPr), which were synthesized, characterized, and successfully applied to the catalytic epoxidation of unfunctionalized alkenes. Present results clearly show that the detailed knowledge of the reaction mechanisms, even for complex processes, is possible nowadays and that the acquired information allows designing catalysts with desired activities.
    Mots-clés : E-POM, POLE 2.
    Pièce jointe Full Text PDF 3.8 Mo (source)

  • L. Tanzi, M. S. Robescu, S. Marzatico, T. Recca, Y. Zhang, M. Terreni, et T. Bavaro, « Developing a Library of Mannose-Based Mono- and Disaccharides: A General Chemoenzymatic Approach to Monohydroxylated Building Blocks », Molecules, vol. 25, nᵒ 23, p. 5764, déc. 2020.
    Résumé : Regioselective deprotection of acetylated mannose-based mono- and disaccharides differently functionalized in anomeric position was achieved by enzymatic hydrolysis. Candida rugosa lipase (CRL) and Bacillus pumilus acetyl xylan esterase (AXE) were immobilized on octyl-Sepharose and glyoxyl-agarose, respectively. The regioselectivity of the biocatalysts was affected by the sugar structure and functionalization in anomeric position. Generally, CRL was able to catalyze regioselective deprotection of acetylated monosaccharides in C6 position. When acetylated disaccharides were used as substrates, AXE exhibited a marked preference for the C2, or C6 position when C2 was involved in the glycosidic bond. By selecting the best enzyme for each substrate in terms of activity and regioselectivity, we prepared a small library of differently monohydroxylated building blocks that could be used as intermediates for the synthesis of mannosylated glycoconjugate vaccines targeting mannose receptors of antigen presenting cells.
    Mots-clés : GOBS, POLE 3.

  • C. Tugny, N. del Rio, M. Koohgard, N. Vanthuyne, D. Lesage, K. Bijouard, P. Zhang, J. Meijide Suárez, S. Roland, E. Derat, O. Bistri-Aslanoff, M. Sollogoub, L. Fensterbank, et V. Mouriès-Mansuy, « β-Cyclodextrin–NHC–Gold(I) Complex (β-ICyD)AuCl: A Chiral Nanoreactor for Enantioselective and Substrate-Selective Alkoxycyclization Reactions », ACS Catalysis, vol. 10, nᵒ 11, p. 5964-5972, juin 2020.
    Résumé : NHC-capped β-cyclodextrin (β-ICyD) was used as a ligand for gold-catalyzed alkoxycyclization reactions. The cavity was found to be responsible for a triple selectivity: (i) the asymmetric shape of the cavity of β-ICyD induced highly stereoselective cyclizations, (ii) the shape of the interior favored the formation of a six-membered ring in the absence of a nucleophile, and finally, (iii) the encapsulation of the metal inside the cavity disfavored the addition of sterically hindered alcohols. Highly enantioselective and substrate-selective alkoxycyclizations of enynes are therefore promoted by the cavity-based molecular reactor (β-ICyD)AuCl.
    Mots-clés : CSOB, GOBS, MACO, POLE 1, POLE 3.
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  • H. Wang, R. Xu, S. Liang, F. Ran, L. Zhang, Y. Zhang, D. Zhou, et S. Xiao, « Selective and facile deacetylation of pentacyclic triterpenoid under methanolic ammonia condition and unambiguous NMR analysis », Chinese Chemical Letters, vol. 31, nᵒ 2, p. 333-336, févr. 2020.

  • Z. Wang, D. Landy, C. Sizun, C. Cézard, A. Solgadi, C. Przybylski, L. de Chaisemartin, L. Herfindal, G. Barratt, et F. - X. Legrand, « Cyclodextrin complexation studies as the first step for repurposing of chlorpromazine », International Journal of Pharmaceutics, vol. 584, p. 119391, 2020.

  • K. Wu, B. Pudasaini, J. Y. Park, S. Top, G. Jaouen, M. - H. Baik, et W. E. Geiger, « Oxidation of Cymantrene-Tagged Tamoxifen Analogues: Effect of Diphenyl Functionalization on the Redox Mechanism », Organometallics, vol. 39, nᵒ 5, p. 679–687, 2020.
    Résumé : The oxidations of 1,1′-di-p-anisolyl-2-cymantrenylbutene (3b) and 1,1′-di-p-hydroxyphenyl-2-cymantrenylbutene (3c) were investigated by electrochemical and spectroscopic experiments and by density functional theory (DFT) calculations. Both compounds undergo a reversible one-electron oxidation followed closely by a partially chemically reversible second oxidation (E1/2 values vs ferrocene: 0.60 and 0.74 V for 3b; 0.63 and 0.78 V for 3c). In comparison to the nonphenyl-functionalized parent, 1,1′-diphenyl-2-cymantrenylbutene (3a), 3b,c have lower and more closely spaced oxidation potentials and more rapid follow-up reactions of their dications, 3b2+ and 3c2+. Shifts in the calculated charge distributions of the neutral compounds and their singly and doubly oxidized products corroborated trends in the measured shifts of Mn–CO νCO frequencies in assigning the redox sites primarily to the diarylbutene fragment. Upon removal of electrons, the lost charge density is partially compensated by the polarizable cymantrenyl tag. The half-lives of the dications 3b2+ and 3c2+ are about 10 s at room temperature in dichloromethane/0.05 M [NBu4][B(C6F5)4]. Their follow-up reactions are initiated by loss of a proton either from a hydroxyl group or from the CH2 group of the diarylbutene unit, giving rise to two products having quinone methide structures. Although the initial oxidation sites of cymantrene-tagged diarylbutenes are primarily ligand based and those of ferrocene-tagged diarylbutenes are metal-based, the ultimate oxidation products of their p-OH- or p-OMe-functionalized derivatives are very similar.
    Mots-clés : CHEMBIO, POLE 3.
    Note Note
    <p>doi: 10.1021/acs.organomet.9b00822</p>

  • C. Xiang, M. Cao, A. Miao, F. Gao, X. Li, G. Pan, W. Zhang, Y. Zhang, P. Yu, et Y. Teng, « Antioxidant activities of anastatin A & B derivatives and compound 38c's protective effect in a mouse model of CCl <sub>4</sub> -induced acute liver injury », RSC Advances, vol. 10, nᵒ 24, p. 14337-14346, 2020.
    Résumé : Anastatins B derivative 38c both had good antioxidant activity in vitro and in vivo . , Anastatins A and B, two flavonoid compounds isolated from desert plant Anastatica hierochuntica , have protective activities for primary rat hepatocytes. Anastatins A and B, and their derivatives, were synthesized by our group previously. In this study, the antioxidant activity and cytotoxicity of these compounds were studied using chemical assessment methods, cell proliferation inhibition experiments, and cell oxidative damage models. The best compound, 38c , was used to study the hepatoprotection activity and mechanism by using a CCl 4 -induced liver injury model in mice. The results show that most of these flavonoid compounds have good antioxidant activity and low cytotoxicity in vitro . Among them, the most potent compound was 38c , which exhibited a protective effect on CCl 4 -induced hepatic injury by suppressing the amount of CYP2E1. These findings indicate that anastatin flavonoid derivatives have potential therapeutic utility against oxidative hepatic injury.
    Mots-clés : GOBS, POLE 3.

  • S. Xiao, D. Zhou, L. Zhang, P. Sinaÿ, et Y. Zhang, « Preparation of unsymmetrically 2A,3B,6C(F)-trihydroxy-per-O-methylated α-cyclodextrin and NMR analysis », Tetrahedron Letters, vol. 61, nᵒ 33, p. 152224, août 2020.

  • G. Xu, S. Leloux, P. Zhang, J. M. Suárez, Y. Zhang, E. Derat, M. Ménand, O. Bistri‐Aslanoff, S. Roland, T. Leyssens, O. Riant, et M. Sollogoub, « Capturing the Monomeric (L)CuH in NHC-Capped Cyclodextrin: Cavity-Controlled Chemoselective Hydrosilylation of α,β-Unsaturated Ketones », Angewandte Chemie International Edition, vol. 59, nᵒ 19, p. 7591-7597, 2020.
    Résumé : The encapsulation of copper inside a cyclodextrin capped with an N-heterocyclic carbene (ICyD) allowed both to catch the elusive monomeric (L)CuH and a cavity-controlled chemoselective copper-catalyzed hydrosilylation of α,β-unsaturated ketones. Remarkably, (α-ICyD)CuCl promoted the 1,2-addition exclusively, while (β-ICyD)CuCl produced the fully reduced product. The chemoselectivity is controlled by the size of the cavity and weak interactions between the substrate and internal C−H bonds of the cyclodextrin.
    Mots-clés : cavities, copper hydride, cyclodextrins, GOBS, hydrosilylation, MACO, N-heterocyclic carbenes, POLE 1, POLE 3, α, β-unsaturated ketones.
    Pièce jointe Full Text PDF 3.2 Mo (source)

  • L. Yang, S. Ruan, A. Zhang, M. Hu, J. Zhang, K. Sheng, J. Tian, Y. Zhang, S. Wu, et J. Li, « A colorimetric and ratiometric fluorescent probe with Meldrum's acid as the recognition group for in vitro and in vivo imaging of hypochlorite », Dyes and Pigments, vol. 175, p. 108144, avr. 2020.

  • L. Zhang, Y. Mazouzi, M. Salmain, B. Liedberg, et S. Boujday, « Antibody-Gold Nanoparticle Bioconjugates for Biosensors: Synthesis, Characterization and Selected Applications », Biosensors and Bioelectronics, vol. 165, p. 112370, oct. 2020.
    Résumé : Antibody-Gold nanoparticle (Ab-AuNP) bioconjugates are widely used in the field of biosensing. This prompted researchers to set up various strategies to conjugate antibodies to gold nanoparticles. Optimal conjugation is of critical importance, as the Ab-AuNP bioconjugates should be stable while maintaining the ability of the antibody to recognize and bind its corresponding antigen. All the same, a high coverage of antibodies on AuNPs is a key-step to build up a sensitive biosensor, but an ideal coverage requires to be perfectly balanced with the orientation and accessibility of the conjugated antibodies. In this review, we intend to provide the reader with the key elements allowing for mastering the conjugation of Ab to AuNP and rationalizing, at the molecular level, the mechanisms involved together with the expected antibody coverages and orientations. We will focus on IgG-type antibodies conjugated to spherical AuNPs as these bioconjugates are the most commonly used ones for biosensors. First, we report an exhaustive survey of the methods of conjugation, via strategies of physisorption and chemisorption. Then we provide a critical restitution of the relevant strategies allowing the quantification of antibodies coverage on gold nanoparticles either through direct analysis of the bioconjugates or indirect analysis of the supernatant. In the last part, we review and discuss selected applications of these Ab-AuNP bioconjugates in optical biosensing.
    Mots-clés : CHEMBIO, Fluorescence, Gold nanoparticles, Immunoglobulin G, Ligand quantification, Localized surface plasmon resonance (LSPR), POLE 3, Surface enhanced Raman scattering (SERS).

  • Z. Zhao, X. Dai, C. Li, X. Wang, J. Tian, Y. Feng, J. Xie, C. Ma, Z. Nie, P. Fan, M. Qian, X. He, S. Wu, Y. Zhang, et X. Zheng, « Pyrazolone structural motif in medicinal chemistry: Retrospect and prospect », European Journal of Medicinal Chemistry, vol. 186, p. 111893, janv. 2020.

  • Z. Zhao, L. Wu, J. Xie, Y. Feng, J. Tian, X. He, B. Li, L. Wang, X. Wang, Y. Zhang, S. Wu, et X. Zheng, « Rhodomyrtus tomentosa (Aiton.): A review of phytochemistry, pharmacology and industrial applications research progress », Food Chemistry, vol. 309, p. 125715, 2020.

  • C. Zheng, R. Huang, T. Bavaro, M. Terreni, M. Sollogoub, J. Xu, et Y. Zhang, « Design, synthesis and biological evaluation of new ganglioside GM3 analogues as potential agents for cancer therapy », European Journal of Medicinal Chemistry, vol. 189, p. 112065, mars 2020.

  • C. Zheng, M. Terreni, M. Sollogoub, et Y. Zhang, « Functional Role of Glycosphingolipids in Cancer », Current Medicinal Chemistry, vol. 27, août 2020.
    Résumé : : Glycosphingolipids (GSLs) are ubiquitous components on animal cell membranes, and exposed on the outer surface. Various studies have demonstrated that they play key roles in cells proliferation, adhesion, motility and differentiation. Usually, the specific types of GSLs are expressed more highly in tumors than in normal tissues, which are known as tumorassociated antigens. It has been revealed that most tumor cells show altered GSLs patterns on their surface, abnormal GSLs signaling and biosynthesis, which together play a major role in tumor development. Tumor-associated GSL antigens have been used in the development of antitumor vaccines. It is no doubt that GSLs play a crucial role in tumor progression and would be a promising target for cancer treatment.
    Mots-clés : GOBS, POLE 3.

  • X. Zhu, G. Xu, L. - M. Chamoreau, Y. Zhang, V. Mouriès‐Mansuy, L. Fensterbank, O. Bistri‐Aslanoff, S. Roland, et M. Sollogoub, « Permethylated NHC-Capped α- and β-Cyclodextrins (ICyDMe) Regioselective and Enantioselective Gold-Catalysis in Pure Water », Chemistry – A European Journal, vol. 26, nᵒ 68, p. 15901-15909, 2020.
    Résumé : A series of water-soluble encapsulated copper(I), silver(I) or gold(I) complexes based on NHC-capped permethylated cyclodextrins (ICyDMe) were developed and used as catalysts in pure water for hydration, lactonization, hydroarylation and cycloisomerization reactions. ICyDMe ligands gave cavity-based high regioselectivity in hydroarylations, and high enantioselectivities in gold-catalyzed cycloisomerizations reactions giving up to 98 % ee in water. These ICyDMe are therefore useful ligands for selective catalysis in pure water.
    Mots-clés : catalysis, cavity, cyclodextrin, GOBS, MACO, N-heterocyclic carbenes, POLE 1, POLE 3, water.
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  • « 15 Silicates in Photocatalysis », in Photocatalysis in Organic Synthesis, 2019ᵉ éd., Stuttgart: Thieme Verlag, 2019, p. 427.
    Résumé : Thieme E-Books & E-Journals
    Mots-clés : CHEMBIO, MACO, POLE 1, POLE 3.

  • F. Abbassi, M. Mbarek, D. Kreher, et K. Alimi, « Cross linking-dependent properties of PVK-MEH-PPV bi-block copolymer: Vibrational, thermal and optical properties », Journal of Physics and Chemistry of Solids, vol. 126, p. 274-279, mars 2019.
    Résumé : Despite its interesting optoelectronic properties, the insolubility of poly (N-vinylcarbazole-poly [2-methoxy-5-2 (ethylhexyloxy)-1,4-phenylenevinylene] (PVK-MEH-PPV) bi-block copolymer has caused some difficulties especially for the elaboration of new composites based on this copolymer and [6,6]-phenyl-C61-butanoate of methyl (PCBM). To solve the problem of insolubility, we first modify quantitatively a main parameter in the chemical synthesis, namely the oxidant agent and then replaced with a new one. Dramatic changes in the vibrational and optical properties are founded by varying the FeCl3 amount in the synthesis way due to the cross-linking of PVK units. This is induces the modulation of copolymers properties particularly theirs emissive proprieties due to the modulation of PVK and MEH-PPV contribution. A red shifting of the maximum of photoluminescence and a quenching was observed with increasing of the oxidation yields. Composite based PCBM and copolymer was elaborated due the solubility of one of copolymer by changing the oxidant agent.
    Mots-clés : Chemical synthesis, Infrared spectroscopy, Optical properties, POLYMERES, Polymers, Thermogravimetric analysis (TGA).

  • U. Alali, A. Vallin, A. Bil, T. Khanchouche, D. Mathiron, C. Przybylski, R. Beaulieu, J. Kovensky, M. Benazza, et V. Bonnet, « The uncommon strong inhibition of α-glucosidase by multivalent glycoclusters based on cyclodextrin scaffolds », Organic & Biomolecular Chemistry, vol. 17, nᵒ 30, p. 7228-7237, 2019.
    Résumé : New inhibitors of α-glucosidase based on perglycosylated cyclodextrins were synthesized via click-chemistry and compared to acarbose. , The homeostasis disruption of d -glucose causes diabetes, a dramatic chronic disease worldwide. Type 1 diabetes is a successfully treatable form, where blood d -glucose is regulated by insulin treatment. In contrast type 2 diabetes, the non-insulin dependent kind, is problematic. The control of the d -glucose blood level via intestinal α- d -glucosidase inactivation can be achieved by using competitive inhibitors, such as iminosugars ( e.g. acarbose) or sulfonium sugar derivatives ( e.g. salacinol). Recently, an unprecedented result showed that multivalent diamond nanoparticles grafted with unmodified sugars displayed α-glucosidase inhibition at low micromolar concentrations. Herein we describe the synthesis of multivalent glycoclusters using cyclodextrins (CDs) as scaffolds and an assessment of their role as inhibitors of α- d -glucosidase. The glycoclusters were efficiently obtained from per-azido α, β and γ-CD derivatives and propargyl glycosides using click-chemistry under microwave irradiation. The methodology was successfully applied to various protected and non-protected propargylated monosaccharides, including both O - and S -glycosides, giving clear evidence of its versatility. The targeted 6- per -glycosylated CDs were isolated in moderate to excellent yields (30–90%) by silica gel chromatography. The results showed inhibition of α-glucosidase from Saccharomyces cerevisiae with IC 50 values in the 32–132 μM range, lower than that of acarbose (IC 50 = ∼250 μM), a well-known competitive inhibitor used in the clinical treatment of type 2 diabetes. Preliminary experiments suggest a mixed-type non-competitive inhibition mode for these new glycoclusters.
    Mots-clés : CSOB, POLE 3.

  • Q. Arnoux, C. Blouzon, D. Li, Y. J. Dappe, A. Smogunov, P. Bonville, L. Tortech, et J. - B. Moussy, « Controlling the magnetic exchange coupling in hybrid heterojunctions via spacer layers of π-conjugated molecules », Physical Review B, vol. 99, nᵒ 14, p. 144405, avr. 2019.
    Résumé : Mastering and understanding the magnetic couplings between magnetic electrodes separated by organic layers are crucial for developing new hybrid spintronic devices. We study the magnetic exchange interactions in organic-inorganic heterojunctions and unveil the possibility of controlling the strength of the magnetic exchange coupling between two ferromagnetic electrodes across π-conjugated molecules’ (α-sexithiophene or para-sexiphenyl) ultrathin film. In Fe3O4/π-conjugated molecules/Co magnetic tunnel junctions, an antiferromagnetic interlayer exchange coupling with variable strength is observed according to the nature of the aromatic rings (thiophene or phenyl groups). The underlying physical mechanism is revealed by ab initio calculations relating the strength of magnetic coupling to the spin moment penetration into a molecular layer at the molecule/Co interface. The prospect that magnetic coupling between two ferromagnetic electrodes can be mediated and tuned by organic molecules opens different perspectives in the way magnetization of organic tunnel junctions or spin valves can be driven.
    Mots-clés : E-POM, POLE 2.
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  • M. Auffray, D. H. Kim, J. U. Kim, F. Bencheikh, D. Kreher, Q. Zhang, A. D'Aléo, J. - C. Ribierre, F. Mathevet, et C. Adachi, « Dithia[3.3]paracyclophane Core: A Versatile Platform for Triplet State Fine-Tuning and Through-Space TADF Emission », Chemistry – An Asian Journal, vol. 14, nᵒ 11, p. 1921-1925, 2019.
    Résumé : Thermally activated delayed fluorescence (TADF) based on through-space donor and acceptor interactions constitute a recent and promising approach to develop efficient TADF emitters. Novel TADF isomers using a dithia[3.3]-paracyclophane building block as a versatile 3D platform to promote through-space interactions are presented. Such a 3D platform allows to bring together the D and A units into close proximity and to probe the effect of their orientation, contact site and distance on their TADF emission properties. This study provides evidence that the dithia[3.3]paracyclophane core is a promising platform to control intramolecular through-space interactions and obtain an efficient TADF emission with short reverse-intersystem crossing (RISC) lifetimes. In addition, this study demonstrates that this design can tune the energy levels of the triplet states and leads to an upconversion from 3CT to 3LE that promotes faster and more efficient RISC to the 1CT singlet state.
    Mots-clés : cyclophanes, donor-acceptor molecules, POLYMERES, TADF lifetime, thermally activated delayed fluorescence, through-space interactions.
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  • V. Ayzac, Q. Sallembien, M. Raynal, B. Isare, J. Jestin, et L. Bouteiller, « A Competing Hydrogen Bonding Pattern to Yield a Thermo-Thickening Supramolecular Polymer », Angewandte Chemie International Edition, vol. 58, nᵒ 39, p. 13849-13853, 2019.
    Résumé : Introduction of competing interactions in the design of a supramolecular polymer (SP) creates pathway complexity. Ester–bis-ureas contain both a strong bis-urea sticker that is responsible for the build-up of long rod-like objects by hydrogen bonding and ester groups that can interfere with this main pattern in a subtle way. Spectroscopic (FTIR and CD), calorimetric (DSC), and scattering (SANS) techniques show that such ester–bis-ureas self-assemble into three competing rod-like SPs. The previously unreported low-temperature SP is stabilized by hydrogen bonds between the interfering ester groups and the urea moieties. It also features a weak macroscopic alignment of the rods. The other structures form isotropic dispersions of rods stabilized by the more classical urea-urea hydrogen bonding pattern. The transition from the low-temperature structure to the next occurs reversibly by heating and is accompanied by an increase in viscosity, a rare feature for solutions in hydrocarbons.
    Mots-clés : hydrogen bonds, pathway complexity, POLYMERES, self-assembly, supramolecular polymers, urea.

  • K. Baatout, F. Saad, A. Baffoun, B. Mahltig, D. Kreher, N. Jaballah, et M. Majdoub, « Luminescent cotton fibers coated with fluorescein dye for anti-counterfeiting applications », Materials Chemistry and Physics, vol. 234, p. 304-310, août 2019.
    Résumé : A simple, rapid and green method to develop fluorescent cotton yarns was established. We report the application of fluorescein (FL) into textile support by impregnation method while keeping the original cotton yarn properties for anti-counterfeiting applications. The FL-coated yarns were characterized by Scanning Electron Microscopy, reflectance and fluorescence spectroscopy. The CIE chromaticity diagram showed a yellowish green emission with a weak yellow coloration of cotton fiber. Mechanical characterization of samples shows that the application of fluorescein did not alter significantly the breaking strength and elongation at break of the fibers, even when using resins. In contrast, to resin-free impregnation process the color fastness test demonstrates that the use of resins as binder is required. The obtained results showed that cotton samples release slowly its contents and fluorescein remains more than five washing cycles.
    Mots-clés : Anti-counterfeiting, Cotton fiber, Fluorescein dye, Fluorescence, POLYMERES, Resin, Washing fastness.

  • G. Basuyaux, A. Desmarchelier, G. Gontard, N. Vanthuyne, J. Moussa, H. Amouri, M. Raynal, et L. Bouteiller, « Extra hydrogen bonding interactions by peripheral indole groups stabilize benzene-1,3,5-tricarboxamide helical assemblies », Chemical Communications, vol. 55, nᵒ 59, p. 8548-8551, juill. 2019.
    Résumé : Benzene-1,3,5-tricarboxamide monomers derived from alkyl esters of tryptophan (BTA Trp) self-assemble into helices with an inner threefold hydrogen bond network surrounded by a second network involving the indole N–H groups. As a consequence of this extra stabilization of its helical assemblies, BTA Trp forms more viscous solutions than a range of ester and alkyl BTAs.
    Mots-clés : ARC, POLE 1, POLYMERES.
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  • P. Bayat, D. Gatineau, D. Lesage, S. Marhabaie, A. Martinez, et R. B. Cole, « Investigation of activation energies for dissociation of host-guest complexes in the gas phase using low-energy collision induced dissociation », Journal of Mass Spectrometry, vol. 54, nᵒ 5, p. 437-448, 2019.

  • L. Ben Haj Hassen, S. Dhifaoui, Y. Rousselin, V. Marvaud, C. Stern, C. E. Schulz, et H. Nasri, « New insights on the electronic, magnetic, electric and molecular structure of a bis-(4-cyanopyridine) iron(III) complex with the meso-tetrakis(4-methoxyphenyl)porphyrin », Inorganica Chimica Acta, vol. 486, p. 675-683, févr. 2019.
    Résumé : We have successfully synthesized and characterized a new low-spin iron(III) bis(4-cyanopyridine) complex with a meso-porphyrin substituted in the para positions of the phenyls by the methoxy group, namely the bis(4-cyanopyridine)[(meso-tetrakis(4-metoxyphenylporphyrinato)]iron(III) trifluoromethanesulfonate chlorobenzene monosolvate complex with the formula [FeIII(TMPP)(4-CNpy)2]SO3CF3.C6H5Cl (I). This species was characterized through ultraviolet–visible, Fourier-transform infrared and Mössbauer spectroscopy as well as by SQUID magnetometry, cyclic voltammetry, and X-ray crystallography. These characterizations indicated that our synthetic heme model is a low-spin (S = 1/2) coordination compound and especially shows that the structural, electronic and the magnetic properties of complex (I) are closely dominated by the presence of the methoxy σ-donor group at the para positions of the meso-porphyrin.
    Mots-clés : Cyclic voltammetry, E-POM, Iron(III) porphyrin, Magnetic properties, POLE 2, X-ray Molecular structure.

  • R. Benchouaia, N. Cissé, B. Boitrel, M. Sollogoub, S. Le Gac, et M. Ménand, « Orchestrating Communications in a Three-Type Chirality Totem: Remote Control of the Chiroptical Response of a Möbius Aromatic System », Journal of the American Chemical Society, vol. 141, nᵒ 29, p. 11583-11593, juill. 2019.

  • L. Benda, B. Doistau, C. Rossi-Gendron, L. - M. Chamoreau, B. Hasenknopf, et G. Vives, « Substrate-dependent allosteric regulation by switchable catalytic molecular tweezers », Communications Chemistry, vol. 2, nᵒ 1, p. 144, 2019.

  • K. Bernardino, J. Świergiel, J. Jadżyn, L. Bouteiller, et A. F. de Moura, « Bulkiness as a design element to increase the rigidity and macrodipole of supramolecular polymers », Journal of Molecular Liquids, vol. 286, p. 110937, juill. 2019.
    Résumé : N,N′-dialkyl ureas in non-polar solvents self-assemble as hydrogen bonded chains. Infrared and dielectric spectroscopy show that more sterically crowded monomers form shorter chains but also larger macrodipoles. This unexpected effect is due to the enhanced rigidity of the bulky assemblies, as confirmed by molecular dynamics simulations.
    Mots-clés : POLYMERES.

  • J. Besnardiere, B. Ma, A. Torres-Pardo, G. Wallez, H. Kabbour, J. M. González-Calbet, H. J. Von Bardeleben, B. Fleury, V. Buissette, C. Sanchez, T. Le Mercier, S. Cassaignon, et D. Portehault, « Structure and electrochromism of two-dimensional octahedral molecular sieve h’-WO3 », Nature Communications, vol. 10, nᵒ 1, p. 327, janv. 2019.
    Résumé : Octahedral molecular sieves (OMS) are built of transition metal-oxygen octahedra that delimit sub-nanoscale cavities. Compared to other microporous solids, OMS exhibit larger versatility in properties, provided by various redox states and magnetic behaviors of transition metals. Hence, OMS offer opportunities in electrochemical energy harnessing devices, including batteries, electrochemical capacitors and electrochromic systems, provided two conditions are met: fast exchange of ions in the micropores and stability upon exchange. Here we unveil a novel OMS hexagonal polymorph of tungsten oxide called h’-WO3, built of (WO6)6 tunnel cavities. h’-WO3 is prepared by a one-step soft chemistry aqueous route leading to the hydrogen bronze h’-H0.07WO3. Gentle heating results in h’-WO3 with framework retention. The material exhibits an unusual combination of 1-dimensional crystal structure and 2-dimensional nanostructure that enhances and fastens proton (de)insertion for stable electrochromic devices. This discovery paves the way to a new family of mixed valence functional materials with tunable behaviors.
    Mots-clés : ERMMES, POLE 2.

  • R. Breitwieser, A. Garnier, T. Auvray, A. - T. Ngo, B. Baptiste, N. Menguy, A. Proust, C. Petit, F. Volatron, et C. Salzemann, « Protective Effect of Polyoxometalates in {Mo132}/Maghemite Binary Superlattices Under Annealing », Frontiers in Chemistry, vol. 7, 2019.
    Résumé : The binary assembly DDA-{Mo132} / OA-γ-Fe2O3 (DDA=didodecyldimethylammonium, {Mo132}=[Mo132O372(CH3COO)30(H2O)72]42-, OA = oleic acid) constitutes one of the two examples in the literature of binary superlattices made of a mixing of nanocrystals and oxo-clusters. In a precedent work, we reported in details the preparation of such magnetic binary systems and studied the effect of the nature of the polyoxometalates (POMs) on the magnetic properties. In the present paper, we study the stability of this model binary assembly under heating at various temperatures. Indeed, especially if magnetic and/or transport properties are targeted, an annealing can be essential to change the phase of the nanocrystals in a more magnetic one and/or to desorb the organic capping of the nano-objects that can constitute an obstacle to the electronic communication between the nano-objects. The binary assembly showed a good stability at temperatures until around 400°C under vacuum thanks to the presence of the POMs that permits to avoid the aggregation of the nanocrystals as well as preserve their periodical arrangement. On the contrary, an assembly made of pure γ-Fe2O3 nanocrystals displays a clear aggregation of the nano-objects from 370°C, as attested by transmission and scanning electronic microscopies and confirmed by magnetic measurements. The stability of such POMs/nanocrystals assemblies opens the way to (i) the elaboration of new binary assemblies from POMs and numerous kinds of nanocrystals with a good control on the magnetic properties and to (ii) the investigation of new physical properties as exchange coupling, or magneto-transport in such systems.
    Mots-clés : annealing, binary superlattices, E-POM, Maghemite, magnetism, POLE 2, Polyoxometalate.
    Pièce jointe Full Text PDF 1.1 Mo (source)

  • A. Cartier, E. Levernier, V. Corcé, T. Fukuyama, A. - L. Dhimane, C. Ollivier, I. Ryu, et L. Fensterbank, « Carbonylation of Alkyl Radicals Derived from Organosilicates through Visible-Light Photoredox Catalysis », Angewandte Chemie International Edition, vol. 58, nᵒ 6, p. 1789-1793, 2019.
    Résumé : Primary, secondary, and tertiary alkyl radicals formed by the photocatalyzed oxidation of organosilicates underwent efficient carbonylation with carbon monoxide (CO) to give a variety of unsymmetrical ketones. This study introduces the possibility of radical carbonylation under a photooxidative regime.
    Mots-clés : carbonylation, CHEMBIO, MACO, photocatalysis, POLE 1, POLE 3, radicals, silicates, three-component reactions.

  • M. Cassé, C. Nisole, H. Dossmann, Y. Gimbert, J. - M. Fourquez, L. Haberkorn, C. Ollivier, et L. Fensterbank, « Trifluoromethyl radical triggered radical cyclization of <italic>N</italic>-benzoyl ynamides leading to isoindolinones », SCIENCE CHINA Chemistry, vol. 62, nᵒ 11, p. 1542-1546, oct. 2019.
    Résumé : Under photocatalytic reductive conditions, trifluoromethyl radical addition onto an ynamide followed by cyclization on a benzoyl moiety produces diverse isoindolinone platforms with good yields. The selectivity of the radical cyclization, <italic>N</italic>-benzoyl vs. <italic>N</italic>-benzyl as radical acceptor and the <italic>E</italic>/<italic>Z</italic> ratio of isomers have been rationalized by modeling.
    Mots-clés : CSOB, MACO, POLE 1, POLE 3.
    Pièce jointe Full Text PDF 1.6 Mo (source)

  • F. Célerse, L. Lagardère, E. Derat, et J. - P. Piquemal, « Massively Parallel Implementation of Steered Molecular Dynamics in Tinker-HP: Comparisons of Polarizable and Non-Polarizable Simulations of Realistic Systems », Journal of Chemical Theory and Computation, vol. 15, nᵒ 6, p. 3694-3709, juin 2019.
    Résumé : Steered molecular dynamic (SMD) is a powerful technique able to accelerate rare event sampling in Molecular Dynamics (MD) simulations by applying an external force to a set of chosen atoms. Despite generating nonequilibrium simulations, SMD remains capable of reconstructing equilibrium properties such as the Potential of Mean Force (PMF). Of course, one would like to use all types of force fields (FF) ranging from classical ones to more advanced polarizable models using point induced dipoles and distributed multipoles such as AMOEBA. To enable such studies, the SMD methodology has been implemented in the framework of the massively parallel Tinker-HP software allowing for both long polarizable and non-polarizable MD simulations of large proteins. To validate this new implementation, we first compared the Tinker-HP SMD results to the literature. Tests have been performed on three different benchmark systems: the M–A deca-alanine (112 atoms), the ubiquitin (9737 atoms), and the CD2CD58 complex (97594 atoms). Non-polarizable (AMBER99, AMBER99SB, CHARMM22/CMAP, and OPLS–AA/L) and polarizable (AMOEBAPRO13 and AMOEBABIO18) force fields have been used. For each one of them, PMFs have been reconstructed and compared in terms of free energy barrier and hydrogen bonding fluctuations behavior over time. Using a SMD velocity of 0.01 Å/ps applied to a set of 20 trajectories, we show that polarizable and non-polarizable force fields do not always agree. As it could be anticipated, strong discrepancies are noticed between polarizable and non-polarizable models when considered in vacuum, whereas results are more comparable when a water environment is added. However, for the largest system, i.e., the CD2CD58 complex, strong differences related to the modeling of a salt bridge are noticed exhibiting some potential issues with classical FFs. Overall, such simulations highlight the importance of the inclusion of polarization effects as PMF free energy barriers computed with AMOEBA always decrease compared to non-polarizable force fields.
    Mots-clés : MACO, POLE 1.
    Pièce jointe Full Text PDF 3.9 Mo (source)

  • L. Chang, S. Thorimbert, et L. Dechoux, « The bio-based methyl coumalate involved Morita–Baylis–Hillman reaction », Organic & Biomolecular Chemistry, vol. 17, nᵒ 10, p. 2784-2791, 2019.
    Résumé : We report the first use of renewable, bio-based, non-hazardous feedstock methyl coumalate (MC) in organocatalyzed Morita–Baylis–Hillman (MBH) reactions. This atom-economical pathway employs inexpensive Et3N as a catalyst in ethanol. Synthon MC efficiently constructs C–C bonds with various imines and aldehydes in moderate to good yields. This catalytic process is triggered via an unprecedented 1,6-conjugated addition, as opposed to the classical MBH reaction. Moreover, this methodology expands Morita–Baylis–Hillman donor capabilities to a 2-pyrone derivative for the first time. MBH adducts described herein could be applied to the synthesis of fine chemicals with biologically active structural cores, such as diphenylmethanol, hydroisobenzofurans, and hydroisoindoles.
    Mots-clés : CHEMBIO, POLE 3.

  • M. Chen, K. Wang, Y. Zhang, M. Zhang, Y. Ma, H. Sun, Z. Jin, H. Zheng, H. Jiang, P. Yu, Y. Zhang, et H. Sun, « New insights into the biological activities of Chrysanthemum morifolium: Natural flavonoids alleviate diabetes by targeting α-glucosidase and the PTP-1B signaling pathway », European Journal of Medicinal Chemistry, vol. 178, p. 108-115, 2019.

  • B. Colsch, A. Damont, C. Junot, F. Fenaille, et J. - C. Tabet, « Experimental evidence that electrospray-produced sodiated lysophosphatidyl ester structures exist essentially as protonated salts », European Journal of Mass Spectrometry, vol. 25, nᵒ 3, p. 333-338, 2019.

  • N. Daffé, J. - R. Jiménez, M. Studniarek, A. Benchohra, M. - A. Arrio, R. Lescouëzec, et J. Dreiser, « Direct Observation of Charge Transfer and Magnetism in Fe4Co4 Cyanide-Bridged Molecular Cubes », The Journal of Physical Chemistry Letters, vol. 10, nᵒ 8, p. 1799-1804, avr. 2019.
    Résumé : We have studied the zero-dimensional cubane molecular correspondent of a Prussian blue analogue Cs–Fe4Co4 at low temperature and high magnetic field by means of L-edge X-ray absorption spectroscopy and X-ray magnetic circular dichroism. We probe the magnetic and electronic structures of Fe and Co separately upon light irradiation, which allows us to observe directly the electron transfer coupled to a spin transition phenomenon within the molecular cubes and to investigate the nature of the metastable photoexcited state. The magnetic moments in the photoexcited state are found to be M = 1.3μB (Mspin = 0.59μB with large orbital moment, Morbit = 0.74μB) for low-spin FeIII and M = 1.5μB (Mspin = 1.08μB with orbital moment, Morbit = 0.41μB) for high-spin CoII at 2 K and 6.8 T. From our results, we evidence that a strong antiferromagnetic coupling between the metal ions can be ruled out.
    Mots-clés : ERMMES, POLE 2.

  • T. Dallagi, M. Saidi, G. Jaouen, et S. Top, « Synthesis and biodistribution of 1-[2-(cyclopentadienyltricarbonyltechnetium-99m)-2-oxo-ethoxy-phenyl]-1,2-di- (p-hydroxyphenyl)but-1-ene for tumor imaging », Journal of Organometallic Chemistry, vol. 891, p. 1-6, 2019.
    Résumé : The high incidence and mortality of breast cancer and other estrogen receptor related tumors motivates efforts to develop innovative imaging probes to effectively diagnose, evaluate the extent of the tumor, and predict the efficacy of treatments while concurrently and selectively delivering anticancer agents to the cancer tissues. In the present study, 1-[2-(cyclopentadienyltricarbonyltechnetium-99m)-2-oxo-ethoxy-phenyl]-1,2-di-(p-hydroxyphenyl)but-1-ene was prepared and investigated as a potential agent for imaging estrogen receptors (ERs) in associated tumors. The compound was obtained in high radiochemical purity and radiochemical yields. The biodistribution of the radioactive compound in mature female rats showed an ER-mediation in the ovarian target tissues as the uptake was reduced by a blocking dose of estradiol. The nonspecific uptake in muscle was relatively low.
    Mots-clés : Biodistribution, CHEMBIO, Estrogen receptor, POLE 3, SPECT, Tc radiolabelling, Tumor, Tumor imaging.

  • A. Damont, M. - F. Olivier, A. Warnet, B. Lyan, E. Pujos-Guillot, E. L. Jamin, L. Debrauwer, S. Bernillon, C. Junot, J. - C. Tabet, et F. Fenaille, « Proposal for a chemically consistent way to annotate ions arising from the analysis of reference compounds under ESI conditions: A prerequisite to proper mass spectral database constitution in metabolomics », Journal of Mass Spectrometry, vol. 54, nᵒ 6, p. 567-582, 2019.

  • S. De, A. Flambard, D. Garnier, P. Herson, F. H. Köhler, A. Mondal, K. Costuas, B. Gillon, R. Lescouëzec, B. Le Guennic, et F. Gendron, « Probing the Local Magnetic Structure of the [FeIII(Tp)(CN)3]− Building Block Via Solid-State NMR Spectroscopy, Polarized Neutron Diffraction, and First-Principle Calculations », Chemistry – A European Journal, vol. 25, nᵒ 52, p. 12120-12136, 2019.
    Résumé : Abstract The local magnetic structure in the [FeIII(Tp)(CN)3]− building block was investigated by combining paramagnetic Nuclear Magnetic Resonance (pNMR) spectroscopy and polarized neutron diffraction (PND) with first-principle calculations. The use of the pNMR and PND experimental techniques revealed the extension of spin-density from the metal to the ligands, as well as the different spin mechanisms that take place in the cyanido ligands: Spin-polarization on the carbon atoms and spin-delocalization on the nitrogen atoms. The results of our combined density functional theory (DFT) and multireference calculations were found in good agreement with the PND results and the experimental NMR chemical shifts. Moreover, the ab-initio calculations allowed us to connect the experimental spin-density map characterized by PND and the suggested distribution of the spin-density on the ligands observed by NMR spectroscopy. Interestingly, significant differences were observed between the pseudo-contact contributions of the chemical shifts obtained by theoretical calculations and the values derived from NMR spectroscopy using a simple point-dipole model. These discrepancies underline the limitation of the point-dipole model and the need for more elaborate approaches to break down the experimental pNMR chemical shifts into contact and pseudo-contact contributions.
    Mots-clés : ERMMES, POLE 2.

  • Y. El Mendili, A. Vaitkus, A. Merkys, S. Gražulis, D. Chateigner, F. Mathevet, S. Gascoin, S. Petit, J. - F. Bardeau, M. Zanatta, M. Secchi, G. Mariotto, A. Kumar, M. Cassetta, L. Lutterotti, E. Borovin, B. Orberger, P. Simon, B. Hehlen, et M. Le Guen, « Raman Open Database: first interconnected Raman–X-ray diffraction open-access resource for material identification », Journal of Applied Crystallography, vol. 52, nᵒ 3, p. 618-625, juin 2019.
    Résumé : The fully open character of the Raman Open Database makes this novel database freely and completely usable by anybody worldwide: academics, those working in industry and the general public.
    Mots-clés : POLYMERES.
    Pièce jointe Full Text PDF 428.1 ko (source)

  • N. Fischer-Durand, D. Lizinska, V. Guérineau, B. Rudolf, et M. Salmain, « ‘Clickable’ cyclopentadienyl iron carbonyl complexes for bioorthogonal conjugation of mid-infrared labels to a model protein and PAMAM dendrimer », Applied Organometallic Chemistry, vol. 33, nᵒ 4, p. e4798, 2019.
    Résumé : Owing to the intrinsic limitations of the conventional bioconjugation methods involving native nucleophilic functions of proteins, we sought to develop alternative approaches to introduce metallocarbonyl infrared labels onto proteins on the basis of the [3?+?2] dipolar azide-alkyne cycloaddition (AAC). To this end, two cyclopentadienyl iron dicarbonyl (Fp) complexes carrying a terminal or a strained alkyne handle were synthesized. Their reactivity was examined towards a model protein and poly (amidoamine) (PAMAM) dendrimer, both carrying azido groups. While the copper (I)-catalysed azide-alkyne cycloaddition (CuAAC) proceeded smoothly with the terminal alkyne metallocarbonyl derivative, labelling by strain-promoted azide-alkyne cycloaddition (SPAAC) was less successful in terms of final coupling ratios. Infrared spectral characterization of the bioconjugates showed the presence of two bands in the 2000?cm?1 region, owing to the stretching vibration modes of the carbonyl ligands of the Fp entities.
    Mots-clés : bioconjugation, CHEMBIO, copper (I)-catalysed azide-alkyne cycloaddition, infrared spectroscopy, metallocarbonyl complex, POLE 3, strain-promoted azide-alkyne cycloaddition.
    Note Note
    <p>doi: 10.1002/aoc.4798</p>

  • K. D. Francesca, S. Lenfant, M. Laurans, F. Volatron, G. Izzet, V. Humblot, C. Methivier, D. Guerin, A. Proust, et D. Vuillaume, « Charge transport through redox active [H7P8W48O184]33− polyoxometalates self-assembled onto gold surfaces and gold nanodots », Nanoscale, vol. 11, nᵒ 4, p. 1863-1878, janv. 2019.
    Résumé : Polyoxometalates (POMs) are redox-active molecular oxides, which attract growing interest for their integration into nano-devices, such as high-density data storage non-volatile memories. In this work, we investigated the electrostatic deposition of the negatively charged [H7P8W48O184]33− POM onto positively charged 8-amino-1-octanethiol self-assembled monolayers (SAMs) preformed onto gold substrates or onto an array of gold nanodots. The ring-shaped [H7P8W48O184]33− POM was selected as an example of large POMs with high charge storage capacity. To avoid the formation of POM aggregates onto the substrates, which would introduce variability in the local electrical properties, special attention has to be paid to the preformed SAM seeding layer, which should itself be deprived of aggregates. Where necessary, rinsing steps were found to be crucial to eliminate these aggregates and to provide uniformly covered substrates for subsequent POM deposition and electrical characterizations. This especially holds for commercially available gold/glass substrates while these rinsing steps were not essential in the case of template stripped gold of very low roughness. Charge transport through the related molecular junctions and nanodot molecule junctions (NMJs) has been probed by conducting-AFM. We analyzed the current–voltage curves with different models: electron tunneling though the SAMs (Simmons model), transition voltage spectroscopy (TVS) method or molecular single energy level mediated transport (Landauer equation) and we discussed the energetics of the molecular junctions. We concluded to an energy level alignment of the alkyl spacer and POM lowest occupied molecular orbitals (LUMOs), probably due to dipolar effects.
    Mots-clés : E-POM, POLE 2.
    Pièce jointe Full Text PDF 4.3 Mo (source)

  • X. Frogneux, L. Hippolyte, D. Mercier, D. Portehault, C. Chanéac, C. Sanchez, P. Marcus, F. Ribot, L. Fensterbank, et S. Carenco, « Direct Synthesis of N-Heterocyclic Carbene-Stabilized Copper Nanoparticles from an N-Heterocyclic Carbene–Borane », Chemistry – A European Journal, vol. 25, nᵒ 49, p. 11481-11485, 2019.
    Résumé : N-Heterocyclic carbene (NHC)-stabilized copper nanoparticles (NPs) were synthesized from an NHC–borane adduct and mesitylcopper(I) under thermal conditions (refluxing toluene for 2.5 h). NPs with a size distribution of 11.6±1.8 nm were obtained. The interaction between Cu NPs and NHC ligands was probed by X-ray photoelectron spectroscopy, which showed covalent binding of the NHC to the surface of the NPs. Mechanistic studies suggested that NHC–borane plays two roles: contributing to the reduction of [CuMes]2 to release Cu0 species and providing NHC ligands to stabilize the copper NPs.
    Mots-clés : carbene ligands, copper, MACO, nanoparticles, POLE 1, radical reactions, reaction mechanisms.
    Pièce jointe Full Text PDF 853.3 ko (source)

  • F. Fus, Y. Yang, S. Lee, S. Top, M. Carriere, A. Bouron, A. Pacureanu, J. Da Silva, M. Salmain, A. Vessieres, P. Cloetens, G. Jaouen, et S. Bohic, « Intracellular localization of an osmocenyl-tamoxifen derivative in breast cancer cells revealed by synchrotron radiation X-ray fluorescence nanoimaging », Angewandte Chemie, vol. 58, nᵒ 11, p. 3461-3465, janv. 2019.
    Résumé : We have recently developed a series of tamoxifen-like metallocifens of the group-8 metals (Fe, Ru and Os) with strong antiproliferative activity on the triple negative breast cancer cells (MDA-MB-231). This property, not observed for the organic analog 4-hydroxytamoxifen, has been associated with the unique redox behavior of metallocenic moieties, readily affording reactive quinone methides in cancer cells. To shed light on the mechanism of action of these molecules, synchrotron radiation X-ray fluorescence (SR-XRF) nanoimaging studies were performed on cells exposed to osmocenyl-tamoxifen (Oc-OH-Tam) to disclose its intracellular distribution using osmium as an intrinsic reporter. High resolution mapping of the lipophilic Oc-OH-Tam in cells, revealed its preferential accumulation in the endomembrane system encompassing endoplasmic reticulum, nuclear envelope and vesicular structures. This is consistent with the ability of the amino nitrogen chain of the compounds to be protonated at physiological pH and responsible for electrostatic interactions between Oc-OH-Tam and membranes. We propose a comprehensive scenario that provides new insight into the cellular behavior and activation of Oc-OH-Tam and advances the understanding of its mechanism of action.
    Mots-clés : bioorganometallic chemistry, breast cancer cells, CHEMBIO, elemental tomography, osmium, POLE 3, synchrotron X-ray fluorescence.
    Note Note
    <p>doi: 10.1002/ange.201812336</p>

  • G. Gaiffe, R. B. Cole, A. Sonnette, N. Floch, et M. C. Bridoux, « Identification of Postblast Residues by DART-High Resolution Mass Spectrometry Combined with Multivariate Statistical Analysis of the Kendrick Mass Defect », Analytical Chemistry, vol. 91, nᵒ 13, p. 8093-8100, juill. 2019.
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