Nos tutelles



Accueil > Publications


publié le , mis à jour le


  • C. Huin, Z. Eskandani, N. Badi, A. Farcas, V. Bennevault-Celton, et P. Guégan, « Anionic ring-opening polymerization of ethylene oxide in DMF with cyclodextrin derivatives as new initiators », Carbohydrate Polymers, vol. 94, nᵒ 1, p. 323-331.
    Résumé : Anionic polymerization initiated by cyclodextrins suffers from a poor solubility of those derivatives in standard polymerization solvents. The possibility to perform ethylene oxide polymerization initiated by monofunctional initiators (allyl alcohol, 2-methoxyethanol) by living ring opening polymerization in DMF, a good solvent for any CD derivative, was demonstrated by SEC, 1H and 13C NMR analyses. The study was extended to the use of native CD as initiator, leading to the synthesis of ill-defined structures, explained by the reactivity scale of the various hydroxyl functions. Two selectively modified CD derivatives are then used to synthesize a new family of star-shaped poly(ethylene oxide) polymers with CD core, having 14 or 21 arms. The polymerization was found to be living and DOSY experiments confirmed the well-defined structures for the synthesized star-polymers.
    Mots-clés : Anionic polymerization, Cyclodextrin, POLE 4, POLYMERES, star polymers.

  • F. Ichou, D. Lesage, X. Machuron-Mandard, C. Junot, R. B. Cole, et J. - C. Tabet, « Collision cell pressure effect on CID spectra pattern using triple quadrupole instruments: a RRKM modeling », Journal of Mass Spectrometry, vol. 48, nᵒ 2, p. 179-186.
    Résumé : Control of the ion internal energy in mass spectrometry is needed to establish a workable mass spectral library. The purpose of this study is to understand and to compare the pressure effects on the collision-induced dissociation (CID) spectrum pattern recorded using triple quadrupole instruments. The monoprotonated Leucine enkephalin [YGGFL, H+] was used as a thermometer molecule to calibrate the electrospray ionization (ESI) and the CID internal energies deposited on the molecular species and the time scale of ion decompositions. The survival yield and the ratio of a4/b4 fragment ions were mainly monitored. The energy uptake for the ESI source geometry used in our study has no impact on the CID spectrum fingerprint. The collision cell pressure for the [YGGFL, H+] has a major influence on the SY curves slope and on the experimental time scale. To demonstrate the pressure effect on internal energy distribution, three models (threshold, thermal and collisional) based on RRKM theory were built using the Masskinetics software. As a result, the limit of each model is discussed, and the investigation demonstrates that the thermal model, using truncated Maxwell-Boltzmann internal energy distribution, is well-suited for simulating the experimental data at high pressure widely used in the analytical conditions. Copyright (c) 2013 John Wiley & Sons, Ltd.
    Mots-clés : activation, calibration, CSOB, distributions, electrospray-ionization, fragmentation, guided ion-beam, induced dissociation, internal energy-distribution, Leucine-enkephalin, MassKinetics, POLE 3, pressure effect, RRKM modeling, tandem mass-spectrometry, triple quadrupole.

  • U. Jacquemard, P. Harpainter, et S. Roland, « Introduction of bulky tert-butyl substituents on the core of N,N′-diaryl N-heterocyclic carbenes through the corresponding vicinal diamines », Tetrahedron Letters, vol. 54, nᵒ 35, p. 4793-4795.
    Résumé : Abstract Highly bulky N,N′-diaryl imidazolinium salts substituted by one or two tert-butyl groups on the heterocyclic backbone and the corresponding silver N-heterocyclic carbene complexes are obtained by the addition of tert-butyl magnesium chloride or tert-butyl lithium on symmetrical 1,2-bisimines derived from 2,6-diisopropylaniline, 2,6-diethylaniline and 2,4,6-trimethylaniline.
    Mots-clés : Carbene ligands, Chiral ligands, GOBS, Imidazoliniums, POLE 3, Silver complexes, Vicinal diamines.

  • K. Jellali, P. Pigeon, F. Trigui, S. Top, S. Aifa, G. Jaouen, et M. El Arbi, « Effect of the amino chain length and the transformation into citric acid salts of aryl-diphenyl-butenes and ferrocenyl-diphenyl-butenes bearing two dimethylaminoalkyl chains on their antimicrobial activities », SpringerPlus, vol. 2, p. 508.
    Résumé : In a previous work we have demonstrated the antimicrobial activity of ferrocenyl or phenyl derivatives of diphenyl butene series. This finding has opened a new area of applications of organometallic compounds., In order to improve these activities, we have synthesized new organic and organometallic diaryl butene compounds with different lengths of their amino chains. These new compounds, and also their ammonium salts, were tested against man pathogenic microorganisms Escherichia coli (ATCC 10536), Pseudomonas aeruginosa (ATCC 15442), Staphylococcus aureus (ATCC 6538) and Enterococcus hirae (ATCC 10541)., It emerged from the tests that the Gram+ bacteria are more sensitive to the compounds than Gram-, and the compounds with 3 carbon amino chains have a better antimicrobial activity than the one having a chain of 2 or 4 carbons., The transformation of compounds to citrate salts was accompanied by a significant regression of antibacterial activity against Pseudomonas aeruginosa, for both organic and ferrocenic molecules. This resistance problem has been solved using hydrochlorides salts rather than citrates one.
    Mots-clés : CHEMBIO, POLE 3.

  • I. k Ahmed, R. Farha, Z. Huo, C. Allain, X. Wang, H. Xu, M. Goldmann, B. Hasenknopf, et L. Ruhlmann, « Porphyrin–polyoxometalate hybrids connected via a Tris-alkoxo linker for the generation of photocurrent », Electrochimica Acta, vol. 110, p. 726-734.

  • G. N. Khairallah, C. C. L. Thum, D. Lesage, J. - C. Tabet, et R. A. J. O’Hair, « Gas-Phase Formation and Fragmentation Reactions of the Organomagnesates [RMgX2]− », Organometallics, vol. 32, nᵒ 8, p. 2319-2328.

  • C. M. Kronfel, A. P. Kuzin, F. Forouhar, A. Biswas, M. Su, S. Lew, J. Seetharaman, R. Xiao, J. K. Everett, L. - C. Ma, T. B. Acton, G. T. Montelione, J. F. Hunt, C. E. C. Paul, T. M. Dragomani, M. N. Boutaghou, R. B. Cole, C. Riml, R. M. Alvey, D. A. Bryant, et W. M. Schluchter, « Structural and Biochemical Characterization of the Bilin Lyase CpcS from Thermosynechococcus elongatus », Biochemistry, vol. 52, nᵒ 48, p. 8663-8676.
    Résumé : Cyanobacterial phycobiliproteins have evolved to capture light energy over most of the visible spectrum due to their bilin chromophores, which are linear tetrapyrroles that have been covalently attached by enzymes called bilin lyases. We report here the crystal structure of a bilin lyase of the CpcS family from Thermosynechococcus elongatus (TeCpcS-III). TeCpcS-III is a 10-stranded beta barrel with two alpha helices and belongs to the lipocalin structural family. TeCpcS-III catalyzes both cognate as well as noncognate bilin attachment to a variety of phycobiliprotein subunits. TeCpcS-III ligates phycocyanobilin, phycoerythrobilin, and phytochromobilin to the alpha and beta subunits of allophycocyanin and to the beta subunit of phycocyanin at the Cys82-equivalent position in all cases. The active form of TeCpcS-III is a dimer, which is consistent with the structure observed in the crystal. With the use of the UnaG protein and its association with bilirubin as a guide, a model for the association between the native substrate, phycocyanobilin, and TeCpcS was produced.
    Mots-clés : binding-protein, chromophore attachment, core-membrane linker, crystal-structure analysis, CSOB, cyanobacterial isca homolog, escherichia-coli, heme oxygenase, phycobiliprotein beta-subunits, POLE 3, sp pcc 6803, synechococcus sp pcc-7002.

  • A. - L. Lainé, E. Adriaenssens, A. Vessières, G. Jaouen, C. Corbet, E. Desruelles, P. Pigeon, R. - A. Toillon, et C. Passirani, « The in vivo performance of ferrocenyl tamoxifen lipid nanocapsules in xenografted tripl

    e negative breast cancer », Biomaterials, vol. 34, nᵒ 28, p. 6949-6956, 2013.
    Résumé : Triple-negative breast cancers (TNBC) represent the most aggressive form of breast cancers and their treatment are challenging due to the tumor heterogeneity. The high death rate and the limited systemic treatment options for TNBC necessitate the search for alternative chemotherapeutics. We previously found that FcOHTAM, an organometallic derivative of hydroxytamoxifen, showed in vitro a strong antiproliferative effect on various breast cancer cell lines, including MDA-MB-231 cells, the archetype of TNBC. In this study, we developed stealth FcOHTAM loaded lipid nanocapsules (LNCs) to further evaluate this novel drug on a TNBC xenografted model. Cell cycle analysis of MDA-MB-231 cells confirmed the preservation of the drug activity through LNCs causing a cycle arrest in phase S after 48 h exposure at the IC50 concentration (2 μm). Two intraperitoneal injections of FcOHTAM loaded LNCs (20 mg/kg) administered to luciferase-transfected MDA-MB-231 tumors bearing mice led to a marked delay in tumor growth. As a consequence, a significantly lower tumor volume was obtained at the end of the experiment with a difference of 36% at day 38 compared to the untreated group. These results represent the first evidence of an in vivo effect of FcOHTAM and ferrocenyl derivatives in general on xenografted breast tumors.
    Mots-clés : Bioluminescence, CHEMBIO, Ferrocene, nanoparticle, POLE 3, Triple negative breast cancers.

  • M. - H. Larraufie, M. Malacria, C. Courillon, C. Ollivier, L. Fensterbank, et E. Lacôte, « Synthesis of natural quinazolinones and some of their analogues through radical cascade reactions involving N-acylcyanamides », Tetrahedron, vol. 69, nᵒ 36, p. 7699-7705.
    Résumé : Abstract Two natural quinazolinones and two analogues can be prepared from the cascade cyclizations of alkyl-substituted N-acylcyanamide radicals, including 5-exo-dig or 6-exo-dig cyclizations onto the cyano group, followed by radical arylations of the resulting amidyl radicals. The fact that one can carry out the cascades from alkyl radicals in addition to aryl, vinyl and aminyl ones, shows the versatility of the method to rapidly access nitrogen-containing polycyclic structures.
    Mots-clés : COS, cyanamides, MACO, POLE 1, Quinazolinones, radical reactions.

  • E. Leclerc, X. Pannecoucke, M. Ethève-Quelquejeu, et M. Sollogoub, « Fluoro-C-glycosides and fluoro-carbasugars, hydrolytically stable and synthetically challenging glycomimetics », Chemical Society Reviews, vol. 42, nᵒ 10, p. 4270-4283.
    Résumé : Fluoro-C-glycosides and fluoro-carbasugars are a particular subclass of hydrolytically stable glycomimetics that are expected to have different, hopefully improved properties thanks to the stereoelectronic features of the fluoroalkyl moiety. This review summarizes the studies devoted to the synthesis of such Carbohydrate chemistry
    Mots-clés : GOBS, POLE 3.

  • H. Lenormand, J. - P. Goddard, et L. Fensterbank, « Spirosilane Derivatives as Fluoride Sensors », Organic Letters, vol. 15, nᵒ 4, p. 748-751.
    Résumé : Spirosilane derivatives have been investigated as fluoride sensors. The reactions between these compounds and different fluoride sources, which resulted In structural alterations, have been monitored and quantified by UV and fluorescence spectroscopy. The high selectivity of these probes for fluoride ions has been demonstrated in either organic or aqueous media.
    Mots-clés : anion recognition, aqueous-media, COS, drinking-water, fluorescent, hypervalent sulfur, MACO, organosilicon compounds, pentaorganosilicates, photophysical properties, POLE 1, selective electrode potentiometry, stabilizing bidentate ligand.

  • J. Liang, J. He, S. Zhu, W. Zhao, Y. Zhang, Y. Ito, et W. Sun, « Preparation of Main Iridoid Glycosides in Fructus Corni by Macroporous Resin Column Chromatography and Countercurrent Chromatography », Journal of Liquid Chromatography & Related Technologies, vol. 36, nᵒ 8, p. 983-999.
    Résumé : Loganin, sweroside, and morroniside, three main iridoid glycosides from Fructus Corni were successfully separated by macroporous resin column chromatography and countercurrent chromatography (CCC). In the first step, D101 macroporous resin was selected for cleaning-up, water was used to elute the column to remove the undesired constituents and then 50% aqueous ethanol was used to elute the targets. The total content of three iridoid glycosides was 51.1% in this process. In the second step, the obtained crude sample was then isolated by CCC using a two-phase solvent system composed of dichloromethane-methanol-n-butanol-water-acetic acid (5:5:2:4:0.1, v/v/v/v/v). From 100mg of a crude sample, 12.6mg of loganin, 5.9mg of sweroside, and 28.5mg of morroniside were obtained with purities of 98.6%, 97.3%, and 99.1% and total recoveries of 90.4%, 91.8%, and 89.1%, respectively, after a two-step purification. The HPLC quantitative analysis and response surface methodology were used for optimization of the separation condition and the target compounds were identified by ESI-MS, 1H NMR, and 13C NMR.
    Mots-clés : cells, constituents, countercurrent chromatography, Fructus Corni, GOBS, hsccc, inflammation, loganin, macroporous resin column chromatography, mice, morroniside, officinalis, POLE 3, purification, scopolamine, sweroside.

  • X. Ling, N. Schaeffer, S. Roland, et M. - P. Pileni, « Nanocrystals: Why Do Silver and Gold N-Heterocyclic Carbene Precursors Behave Differently? », Langmuir, vol. 29, nᵒ 41, p. 12647-12656.
    Résumé : Synthesizing stable Au and Ag nanocrystals of narrow size distribution from metal-N-heterocyclic carbene (NHC) complexes remains a challenge, particularly in the case of Ag and when NHC ligands with no surfactant-like properties are used. The formation of nanocrystals by one-phase reduction of metal-NHCs (metal = Au, Ag) bearing common NHC ligands, namely 1,3-diethylbenzimidazol-2-ylidene.(L-1), 1,3-bis(mesityl)imidazol-2-ylidene (L-2), and 1,3-bis(2,6-(Pr2C6H3)-Pr-i)imidazol-2-ylidene (L-3), is presented herein. We show that both Au and Ag nanocrystals displaying narrow size distribution can be formed by reduction with amine boranes. The efficiency of the process and the average size and size distribution of the nanocrystals markedly depend on the nature of the metal and NHC ligand, on the sequence in the reactant addition (i.e., presence or absence of thiol during the reduction step), and on the presence or absence of oxygen. Dodecanethiol was introduced to produce stable nanocrystals associated with narrow size distributions. A specific reaction is observed with Ag NHCs in the presence of thiols whereas Au-NHCs remain unchanged. Therefore, different organometallic species are involved in the reduction step to produce the seeds. This can be correlated to the lack of effect of NHCs on Ag nanocrystal size. In contrast, alteration of Au nanocrystal average size can be achieved with a NHC ligand of great steric bulk (L-3). This demonstrates that a well-defined route for a given metal cannot be extended to another metal.
    Mots-clés : Catalysis, chemistry, complexes, GOBS, Heterocycles, layered structure, metal nanoparticles, nucleation, phase synthesis, POLE 3, size, solid-state, system.

  • M. M. Lorion, D. Gasperini, J. Oble, et G. Poli, « Palladium-Catalyzed Arylic/Allylic Aminations: Permutable Domino Sequences for the Synthesis of Dihydroquinolines from Morita-Baylis-Hillman Adducts », Organic Letters, vol. 15, nᵒ 12, p. 3050-3053.
    Résumé : An efficient palladium-catalyzed synthesis of 1,2-dihydroquinolines has been developed via the reaction between anilines and Morita-Baylis-Hillman adducts derived from o-bromobenzaldehyde. This new Pd(0)-catalyzed pseudo-domino type I sequence Involves a Buchwald-Hartwig arylic amination and an allylic amination. When starting from an o-bromo allylic alcohol, the chronology Is arylic amination/allylic arylation. However, the sequence reverses when the reaction is performed on the corresponding o-bromo allylic acetate.
    Mots-clés : acetates, Allylic alkylation, aromatic-amines, asymmetric-synthesis, cobalt nanoparticles, intramolecular heck reaction, one-pot synthesis, organic-synthesis, POLE 1, ring-closing metathesis, ROCS, sequential actions, SSO.

  • M. M. Lorion, B. Matt, S. Alves, A. Proust, G. Poli, J. Oble, et G. Izzet, « Versatile Post-functionalization of Polyoxometalate Platforms By Using An Unprecedented Range of Palladium-Catalyzed Coupling Reactions », Chemistry - A European Journal, vol. 19, nᵒ 38, p. 12607-12612.
    Mots-clés : Allylic alkylation, clusters, cross-coupling, CSOB, dawson, E-POM, head groups, Heck reaction, hybrid, Keggin, organic-inorganic hybrids, Palladium, POLE 1, POLE 2, POLE 3, Polyoxometalates, polyoxotungstates, POM, ROCS, SSO, surfaces, surfactants.
  • N. Madern, B. Talbi, et M. Salmain, « Aqueous phase transfer hydrogenation of aryl ketones catalysed by achiral ruthenium(II) and rhodium(III) complexes and their papain conjugates », Applied Organometallic Chemistry, vol. 27, nᵒ 1, p. 6-12.
    Résumé : Several ruthenium and rhodium complexes including 2,2′-dipyridylamine ligands substituted at the central N atom by an alkyl chain terminated by a maleimide functional group were tested along with a newly synthesized Rh(III) complex of unsubstituted 2,2′-dipyridylamine as catalysts in the transfer hydrogenation of aryl ketones in neat water with formate as hydrogen donor. All of them except one led to the secondary alcohol products with conversion rates depending on the metal complex. Site-specific anchoring of the N-maleimide complexes to the single free cysteine residue of the cysteine endoproteinase papain endowed this protein with transfer hydrogenase properties towards 2,2,2-trifluoroacetophenone. Quantitative conversions were reached with the Rh-based biocatalysts, while modest enantioselectivities were obtained in certain reactional conditions. Copyright © 2012 John Wiley & Sons, Ltd.
    Mots-clés : acetophenone, artificial metalloenzyme, CHEMBIO, dipyridylamine, POLE 3, Rhodium, Ruthenium, secondary alcohol.

  • G. Maestri, M. Malacria, et E. Derat, « Radical Pd(III)/Pd(I) reductive elimination in palladium sequences », Chemical Communications, vol. 49, nᵒ 88, p. 10424-10426.
    Résumé : Open-shell mechanisms are often at work in catalytic sequences involving first-row transition metals while usually not considered in palladium chemistry. Herein a computational study suggests their possible relevance in catalytic methods involving paramagnetic Pd(III) intermediates. Indeed C–C bond forming reductive elimination previously thought to occur in Pd(IV) complexes has lower barriers in neutral, radical Pd(III) intermediates instead. These species could form upon addition on Pd(II) of an aryl radical generated via single electron transfer from a photo-active ruthenium complex and have the perfect stereoelectronic arrangement to smoothly undergo the coupling process.
    Mots-clés : c-h arylation, carbon-carbon, Catalysis, chemistry, Copper, COS, coupling reactions, density functionals, MACO, photocatalysis, pincer complex, POLE 1.

  • M. Malacria et G. Maestri, « Palladium/Norbornene Catalytic System: Chelation as a Tool To Control Regioselectivity of Pd(IV) Reductive Elimination », The Journal of Organic Chemistry, vol. 78, nᵒ 4, p. 1323-1328.
    Résumé : Palladium/norbornene joint catalysis gives rise to a unique system in which the three most common formal oxidation states of the metal are at work in the same cycle (0, II, and IV). This paper summarizes a selection of synthetic applications and the feasibility of Pd(IV) formation by oxidative addition of aryl halides. On this intermediate, the presence of a suitable chelating group could trigger unexpected aryl–norbornyl coupling, further broadening the scope of readily available polycyclic frameworks.
    Mots-clés : MACO, POLE 1.

  • R. M. Mallorquin, G. Vincent, E. Derat, M. Malacria, J. - P. Goddard, et L. Fensterbank, « New Elements on the Behaviour of a Bissulfinylmethyl Radical », Australian Journal of Chemistry, vol. 66, nᵒ 3, p. 346-353.
    Résumé : In this article, we have studied the generation of a bissulfinylmethyl radical from the corresponding TEMPO and phenylselenyl bissulfoxide precursors. No univocal formation of the bissulfinylmethyl radical has been observed. Instead, complex mixtures have been obtained in thermal or photochemical conditions, showing prominent C-S homolytic bond cleavage.
    Mots-clés : alkenes, alkoxyamines, alkynes, bis-sulfoxides, COS, MACO, oxidation, POLE 1, thiols.

  • J. de J. C. Marinero, M. Lapierre, V. Cavaillès, R. Saint-Fort, A. Vessières, S. Top, et G. Jaouen, « Efficient new constructs against triple negative breast cancer cells: synthesis and preliminary biological study of ferrocifen–SAHA hybrids and related species », Dalton Transactions, vol. 42, nᵒ 43, p. 15489-15501.
    Résumé : Chemotherapeutic agents combining several active groups within a single molecule can modulate multiple cellular pathways and, thus, exhibit higher efficacy than single-target drugs. In this study, six new hybrid compounds combining tamoxifen (TAM) or ferrocifen (FcTAM) structural motifs with suberoylanilide hydroxamic acid (SAHA) were synthesised and evaluated. Antiproliferative activity was first explored in cancer cell lines. Combining FcTAM and SAHA structural motifs to form the unprecedented FcTAM–SAHA hybrid molecule led to an increased cytotoxicity (IC50 = 0.7 μM) in triple-negative MDA-MB-231 breast cancer cells when compared to FcTAM or SAHA alone (IC50 = 2.6 μM and 3.6 μM, respectively), while the organic hybrid analogue TAM–SAHA was far less cytotoxic (IC50 = 8.6 μM). In hormone-dependent MCF-7 breast cancer cells, FcTAM–SAHA was more active (IC50 = 2.0 μM) than FcTAM (IC50 = 4.4 μM) and TAM–SAHA (IC50 > 10 μM), but less toxic than SAHA (IC50 = 1.0 μM). Surprisingly, FcTAM–PSA, an N1-phenylsuberamide derivative, also possessed strong antiproliferative activity (IC50 = 0.5 μM and 1.8 μM in MDA-MB-231 and MCF-7 cells, respectively). Subsequent biochemical studies indicate that estrogen receptor alpha (ERα) and histone deacetylases (HDAC) are not the main targets of the hybrid compounds for their antiproliferative effect. Interestingly, both organometallic compounds were able to induce p21waf1/cip1 gene expression in MCF-7 breast cancer cells in accordance with their antiproliferative activity.
    Mots-clés : CHEMBIO, POLE 3.

  • B. Matt, J. Fize, J. Moussa, H. Amouri, A. Pereira, V. Artero, G. Izzet, et A. Proust, « Charge photo-accumulation and photocatalytic hydrogen evolution under visible light at an iridium(iii)-photosensitized polyoxotungstate », Energy & Environmental Science, vol. 6, nᵒ 5, p. 1504.

  • B. Matt, X. Xiang, A. L. Kaledin, N. Han, J. Moussa, H. Amouri, S. Alves, C. L. Hill, T. Lian, D. G. Musaev, G. Izzet, et A. Proust, « Long lived charge separation in iridium(III)-photosensitized polyoxometalates: synthesis, photophysical and computational studies of organometallic–redox tunable oxide assemblies », Chemical Science, vol. 4, nᵒ 4, p. 1737-1745.
    Résumé : Keggin and Dawson-type polyoxometalates (POMs) covalently grafted to heteroleptic cyclometalated iridium(iii) complexes (POM–[Ir] dyads) have been prepared by postfunctionalization of organosilyl and organotin POM derivatives. Electronic properties of these 4 photosensitized POM–[Ir] dyads were evaluated by
    Mots-clés : ARC, CSOB, E-POM, POLE 1, POLE 2, POLE 3, POM.

  • M. - A. Maubert, E. Quévrain, E. Capton, J. P. Grill, G. Thomas, M. Bachelet, D. Rainteau, G. Trugnan, J. - C. Tabet, J. Masliah, et C. Afonso, « High-resolution mass spectrometry and partial <i>de novo</i> sequencing constitute a useful approach for determining the profile of chemokine secretion following the stimulation of human intestinal epithelial cells », Rapid Communications in Mass Spectrometry, vol. 27, nᵒ 19, p. 2179-2187.

  • K. Micoine, M. Malacria, E. Lacôte, S. Thorimbert, et B. Hasenknopf, « Regioselective Double Organic Functionalization of Polyoxotungstates through Electrophilic Addition of Aromatic Isocyanates to [P2W17O61(SnR)]7– », European Journal of Inorganic Chemistry, vol. 2013, nᵒ 10-11, p. 1737–1741.
    Résumé : The direct attachment of several different organic molecules to a single polyoxometalate remains a challenge in the field of functionalized polyoxometalates. In this paper, we show that an organotin-functionalized Dawson-type polyoxotungstate [P2W17O61(SnR)]7– reacts with aromatic isocyanates ArNCO to yield new doubly functionalized compounds [P2W17O61(SnR)(CONHAr)]6–. Both organic moieties, Ar and R, can be varied independently; we have tested nine Ar and three R groups. Therefore, this synthetic methodology represents a way to graft two distinct functional molecules directly onto a polyoxometalate.
    Mots-clés : CHEMBIO, COS, Electrophilic addition, GOBS, Heterocycles, MACO, organic–inorganic hybrid composites, POLE 1, POLE 3, Polyoxometalates, SUPRA, synthesis design, Tungsten.

  • A. Mondal, L. - M. Chamoreau, Y. Li, Y. Journaux, M. Seuleiman, et R. Lescouezec, « WCo Discrete Complex Exhibiting Photo- and Thermo-Induced Magnetisation », Chemistry-a European Journal, vol. 19, nᵒ 24, p. 7682-7685, juin 2013.
    Mots-clés : chain, co, cobalt, crystal-structure, cyanide, cyanide ligand, electron-transfer, ERMMES, MMMAX, Photomagnetism, POLE 2, Tungsten.

  • A. Mondal, P. - I. Dassie, L. - M. Chamoreau, Y. Journaux, M. Julve, L. Lisnard, et R. Lescouëzec, « Combining Cyanometalates and Coordination Clusters: An Alternative Synthetic Route toward Original Molecular Materials », Crystal Growth & Design, vol. 13, nᵒ 10, p. 4190-4194, oct. 2013.
    Résumé : As an original synthetic route to molecular magnetic materials, we have reacted partially blocked cyanometalates with preformed coordination cluster. The association of the fac-[Fe(Tp)(CN)(3)](-) assembling metalloligand with the [Cu-3(OH)(pz)(3)](2+) trigonal cluster has afforded a novel coordination network where the trimetallic copper(II) nodes are linked by the iron(III) complexes into chains and by coordinating acetate into a two-dimensional framework.
    Mots-clés : anisotropy, chain, complexes, crystal-structures, cyanide, ERMMES, magnetic-properties, MMMAX, networks, new-generation, POLE 2, polymers, secondary building units.

  • A. Mondal, S. Durdevic, L. - M. Chamoreau, Y. Journaux, M. Julve, L. Lisnard, et R. Lescouëzec, « A cyanide and hydroxo-bridged nanocage: a new generation of coordination clusters », Chemical Communications, vol. 49, nᵒ 12, p. 1181, 2013.

  • A. Mondal, Y. Li, M. Seuleiman, M. Julve, L. Toupet, M. Buron-Le Cointe, et R. Lescouëzec, « On/Off Photoswitching in a Cyanide-Bridged {Fe <sub>2</sub> Co <sub>2</sub> } Magnetic Molecular Square », Journal of the American Chemical Society, vol. 135, nᵒ 5, p. 1653-1656, févr. 2013.

  • J. - P. Monserrat, K. N. Tiwari, L. Quentin, P. Pigeon, G. Jaouen, A. Vessières, G. G. Chabot, et E. A. Hillard, « Ferrocenyl flavonoid-induced morphological modifications of endothelial cells and cytotoxicity against B16 murine melanoma cells », Journal of Organometallic Chemistry, vol. 734, p. 78-85, 2013.
    Résumé : With the aim of improving the cytotoxic and vascular disrupting activities of flavonoids, several classes of ferrocenyl-modified flavonoids were prepared and tested on cancer and endothelial cells. Three ten-member series of ferrocenyl flavonoids: chalcones ((E)-1-(R-2′-hydroxyphenyl)-3-ferrocenylprop-2-en-1-ones), aurones ((Z)-R-2-(ferrocenylidene)benzofuran-3-ones) and flavones (R-2-ferrocenyl-chromen-4-ones) were synthesized by recently reported methods. Three ferrocenyl flavonols (R-3-hydroxy-2-ferrocenyl-chromen-4-ones) and four ferrocenyl flavanones (3-ferrocenylmethylidenyl-R-2-phenylchroman-4-ones) were also obtained. All compounds were evaluated for their cytotoxic effects on a cancer cell line (B16 murine melanoma) and for their morphological effects on endothelial cells (EAhy 926). Some interesting structure–activity relationships were disclosed: of all the compounds, the halogen-substituted aurones showed the best cytotoxic activity, with IC50 values ranging between 12 and 18 μM. Ferrocenyl flavonols and ferrocenyl flavanones with substitution in the 3-position (–OH and C–Fc respectively) were not active against cancer or endothelial cells. Some of the ferrocenyl flavones caused the endothelial cells to adopt a round shape (“rounding up”) at submicromolar concentrations, which can be predictive of vascular disrupting activity. The most morphologically active flavones showed only moderate cytotoxicity against cancer cells, indicating that they may primarily act as antivascular agents.
    Mots-clés : Antivascular agents, Aurones, Bioorganometallic chemistry, CHEMBIO, cytotoxicity, Ferrocene, Flavones, POLE 3.

  • J. Moussa, L. M. Chamoreau, et H. Amouri, « Planar Chiral Iridium Complexes with the Δ-TRISPHAT Anion: Toward the First Enantiopure o-Quinone Methide π-Complex », Chirality, vol. 25, nᵒ 8, p. 449–454.
    Résumé : We describe the resolution of a planar chiral cationic iridium complex [Cp*Ir(η5-2-methyl-oxodienyl)][OT f] () following the counterion strategy, where anion metathesis by Δ-TRISPHAT generates the two diastereomers (pR, pS)-[Cp*Ir(η5-2-methyl-oxodienyl)][Δ-TRISPHAT] (, ). Upon fractional crystallization both compounds were separated as confirmed by 1H nuclear magnetic resonance (NMR) and circular dichroism studies recorded in solution. The latter represents the key-complex precursors for the enantioselective synthesis of metallated o-quinone methide complexes (, ). Chirality 25:449–454, 2013. © 2013 Wiley Periodicals, Inc.
    Mots-clés : ARC, chirality, circular dichroism, diastereomeric separation, NMR, POLE 1, quinone methides.

  • J. Moussa, K. M. - C. Wong, X. F. Le Goff, M. N. Rager, C. K. - M. Chan, V. W. - W. Yam, et H. Amouri, « Dinuclear Platinum(II) Terpyridyl Complexes with a para-Diselenobenzoquinone Organometallic Linker: Synthesis, Structures, and Room-Temperature Phosphorescence », Organometallics, vol. 32, nᵒ 17, p. 4985-4992.
    Résumé : We report the synthesis of a unique class of luminescent heterotrinuclear complexes of the general formulas [Pt(terpy){Cp*Ir-p-(?4-C6H4Se2)}Pt(terpy)][X]4 (X = OTf, 3a; PF6, 3b; BF4, 3c; ClO4, 3d; BPh4, 3e). In these coordination assemblies two Pt(terpy) moieties are held by a stable ?4-diseleno-p-benzoquinone complex [Cp*Ir-p-(?4-C6H4Se2)]. The molecular structures of solvates of 3a and 3b were ascertained by single-crystal X-ray diffraction study and confirmed the formation of the target molecules. The solid-state packing of two of these complexes confirms the presence of π?π and Pt···Pt interactions among individual units providing a 1D supramolecular chain for 3a, while a dimer species is obtained for 3b, illustrating the effect of the counterion on directing the crystal packing of the individual molecules. All compounds show phosphorescence in the red region (685?705 nm) in fluid solution and in the solid state at room temperature, unlike the analogous compound Pt(terpy){Cp*Ir-p-(?4-C6H4S2)}Pt(terpy)][CF3SO3]4 obtained with a dithiobenzoquinone organometallic linker, which is only luminescent at low temperature.
    Mots-clés : ARC, POLE 1.

  • A. Nion, N. Katsonis, A. Marchenko, C. Aubert, et D. Fichou, « Influence of molecular length on the adsorption of linear trimethylsilylacetylene derivatives at the n-tetradecane/Au(111) interface: chemisorption vs. physisorption », New Journal of Chemistry, vol. 37, nᵒ 8, p. 2261-2265, 2013.
    Résumé : Adsorption of two trimethylsilylacetylene (TMSA) derivatives bearing linear alkyl chains of different lengths has been studied at the n-tetradecane/Au(111) interface. The lying or standing orientation of TMSA compounds on the gold surface shows that adsorption is not only controlled by the chemical reactivity of the molecules but also by their size.
    Mots-clés : au(111), COS, FICHOU, Gold, long, MACO, NASCO, organosilane, POLE 1, POLE 2, scanning-tunneling-microscopy, self-assembled monolayers, stm, surfaces.
    Pièce jointe

  • A. Pancotti, J. Wang, P. Chen, L. Tortech, C. - M. Teodorescu, E. Frantzeskakis, et N. Barrett, « X-ray photoelectron diffraction study of relaxation and rumpling of ferroelectric domains in BaTiO3(001) », Physical Review B, vol. 87, nᵒ 18, p. 184116.
    Résumé : The surface of a ferroelectric BaTiO3(001) single crystal was studied using synchrotron radiation induced x-ray photoelectron diffraction (XPD), x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and low-energy electron diffraction (LEED). AFM, XPS, and LEED show that the surface is BaO terminated with a (1 x 1) reconstruction. The Ba 4d, Ti 2p, and O 1s XPD results were compared with multiple scattering simulations for out-of- (P+, P) and in-plane (P-in) polarizations using a genetic algorithm to determine atomic rumpling and interlayer relaxation. Linear combinations of the XPD simulations of the surface structure of each polarization state allow determination of the domain ordering. The best agreement with experiment is found for 55% P+, 38% P-, and 7% P-in. The rumpling is smaller at the surface than in the bulk, suggesting that both domain ordering and surface structural changes contribute to screening of the polarization.
    Mots-clés : NASCO, NSCO, POLE 2, surface.

  • A. Parrot, G. Izzet, L. - M. Chamoreau, A. Proust, O. Oms, A. Dolbecq, K. Hakouk, H. El Bekkachi, P. Deniard, R. Dessapt, et P. Mialane, « Photochromic Properties of Polyoxotungstates with Grafted Spiropyran Molecules », Inorganic Chemistry, vol. 52, nᵒ 19, p. 11156-11163.
    Résumé : The first systems associating in a single molecule polyoxotungstates (POTs) and photochromic organic groups have been elaborated. Using the (TBA)4[PW11O39{Sn(C6H4I)}] precursor, two hybrid organic?inorganic species where a spiropyran derivative (SP) has been covalently grafted onto a {PW11Sn} fragment via a Sonogashira coupling have been successfully obtained. Alternatively, a complex containing a silicotungstate {PW11Si2} unit connected to two spiropyran entities has been characterized. The purity of these species has been assessed using several techniques, including 1H and 31P NMR spectroscopy, mass spectrometry, and electrochemical measurements. The optical properties of the hybrid materials have been investigated both in solution and in the solid state. These studies reveal that the grafting of SPs onto POTs does not significantly alter the photochromic behavior of the organic chromophore in solution. In contrast, these novel hybrid SP?POT materials display highly effective solid-state photochromism from neutral SP molecules initially nonphotochromic in the crystalline state. The photoresponses of the SP?POT systems in the solid state strongly depend on the nature and the number of grafted SP groups.
    Mots-clés : E-POM, POLE 2, POM.

  • N. Pavlicek, C. Herranz-Lancho, B. Fleury, M. Neu, J. Niedenfuehr, M. Ruben, et J. Repp, « High-resolution scanning tunneling and atomic force microscopy of stereochemically resolved dibenzo[a,h]thianthrene molecules », Physica Status Solidi B-Basic Solid State Physics, vol. 250, nᵒ 11, p. 2424-2430, nov. 2013.
    Résumé : Recently, we reported on the bistable configurational switching of dibenzo[a,h]thianthrene (DBTH) molecules adsorbed on NaCl using combined low-temperature scanning tunneling and atomic force microscopy (STM/AFM). Here, we discuss the intra-molecular contrast in AFM images of the molecules as a function of the tip-molecule distance. Our experiments show that ridges in the frequency shift do not necessarily correlate with chemical bonds in this case of a non-planar molecule. To explain this finding we compare images acquired at different tip-molecule distances to the calculated electron density of the molecules obtained from density functional theory calculations (DFT). In addition, we analyze the probability of finding different configurations after adsorption onto the surface. DBTH molecules in two configurations probed by a CO-functionalized tip. Insets show AFM (left) and STM (right) images of a U molecule.
    Mots-clés : ERMMES, MMMAX, POLE 2.

  • D. Plażuk, J. Zakrzewski, M. Salmain, A. Błauż, B. Rychlik, P. Strzelczyk, A. Bujacz, et G. Bujacz, « Ferrocene–Biotin Conjugates Targeting Cancer Cells: Synthesis, Interaction with Avidin, Cytotoxic Properties and the Crystal Structure of the Complex of Avidin with a Biotin–Linker–Ferrocene Conjugate », Organometallics, vol. 32, nᵒ 20, p. 5774-5783, 2013.
    Résumé : Friedel–Crafts acylation of ferrocene with a biotin-derived carboxylic acid having 6-aminohexanoyl linkers attached to the biotin carboxylic group and with desthiobiotin afforded the corresponding ferrocene–biotin bioconjugates. These compounds as well as biotinyl ferrocenyl ketone exhibit high affinity for avidin. Their cytotoxicity against cancer cell lines having various levels of biotin receptors (SMVT) was measured and revealed that lines displaying high levels of SMVT (SW620) were the most susceptible. This suggests that biotin serves as a biological vector delivering cytotoxic ferrocenyl moieties to cancer cells. The crystal structure of the complex of avidin with a conjugate having two linker units between biotin and ferrocene was determined and revealed stabilization of several different conformations of the ligand within the protein binding pocket.
    Mots-clés : CHEMBIO, POLE 3.

  • Y. Prado, M. - A. Arrio, F. Volatron, E. Otero, C. C. D. Moulin, P. Sainctavit, L. Catala, et T. Mallah, « Magnetic Anisotropy of Cyanide-Bridged Core and CoreShell Coordination Nanoparticles Probed by X-ray Magnetic Circular Dichroism », Chemistry-a European Journal, vol. 19, nᵒ 21, p. 6685-6694, mai 2013.
    Résumé : The local symmetry and local magnetic properties of 6nm-sized, bimetallic, cyanide-bridged CsNiCr(CN)6 coordination nanoparticles 1 and 8nm-sized, trimetallic, CsNiCr(CN)6@CsCoCr(CN)6 coreshell nanoparticles 2 were studied by X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD). The measurements were performed at the NiII, CoII, and CrIII L2,3 edges. This study revealed the presence of distorted NiII sites located on the particle surface of 1 that account for the uniaxial magnetic anisotropy observed by SQUID measurements. For the coreshell particles, a combination of the exchange anisotropy between the core and the shell and the pronounced anisotropy of the CoII ions is the origin of the large increase in coercive field from 120 to 890Oe on going from 1 to 2. In addition, XMCD allows the relative orientation of the magnetic moments throughout the coreshell particles to be determined. While for the bimetallic particles of 1, alignment of the magnetic moments of CrIII ions with those of NiII ions leads to uniform magnetization, in the coreshell particles 2 the magnetic moments of the isotropic CrIII follow those of CoII ions in the shell and those of NiII ions in the core, and this leads to nonuniform magnetization in the whole nanoobject, mainly due to the large difference in local anisotropy between the CoII ions belonging to the surface and the NiII ions in the core.
    Mots-clés : absorption, behavior, coordination networks, coreshell structures, ERMMES, MMMAX, POLE 2.

  • S. S. Quadri, R. E. Stratford, S. M. Boué, et R. B. Cole, « Screening and Identification of Glyceollins and Their Metabolites by Electrospray Ionization Tandem Mass Spectrometry with Precursor Ion Scanning », Analytical Chemistry, vol. 85, nᵒ 3, p. 1727-1733.
    Résumé : A method has been developed for screening glyceollins and their metabolites based on precursor ion scanning. Under higher-energy collision conditions with the employment of a triple quadrupole mass spectrometer in the negative ion mode, deprotonated glyceollin precursors yield a diagnostic radical product ion at m/z 148. We propose this resonance-stabilized radical anion, formed in violation of the even-electron rule, to be diagnostic of glyceollins and glyceollin metabolites. Liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) established that scanning for precursors of m/z 148 can identify glyceollins and their metabolites from plasma samples originating from rats dosed with glyceollins. Precursor peaks of interest were found at m/z 337, 353, 355, 417, and 433. The peak at m/z 337 corresponds to deprotonated glyceollins, whereas the others represent metabolites of glyceollins. Accurate mass measurement confirmed m/z 417 to be a sulfated metabolite of glyceollins. The peak at m/z 433 is also sulfated, but it contains an additional oxygen, as c!onfirmed by accurate mass measurement. The latter metabolite differs from the former likely by the replacement of a hydrogen with a hydroxyl moiety. The peaks at m/z 353 and 355 are proposed to correspond to hydroxylated metabolites of glyceollins, wherein the latter additionally undergoes a double bond reduction.
    Mots-clés : CSOB, POLE 3.

    alt="Pièce jointe"/> ACS Full Text PDF w/ Links
  • A. Rajab, M. Touma, H. Rudler, C. Afonso, et M. Seuleiman, « Slow, spontaneous degradation of lansoprazole, omeprazole and pantoprazole tablets: isolation and structural characterization of the toxic antioxidants 3H-benzimidazole-2-thiones. », Die Pharmazie, vol. 68, nᵒ 9, sept. 2013.
    Résumé : The spontaneous degradation of lansoprazole, omeprazole and pantoprazole tablets upon long-term and forced storage conditions was determined by high performance liquid chromatography (HPLC). The more abundant products could be isolated by liquid chromatography and their molecular weights determined by Mass Spectrometry (MS). Their structures, established according to their spectroscopic data, were compared to those of either the literature or of authentic samples. Thus lansoprazole led mainly to a mixture of 3H-benzimidazole-2-thione (2a) and 3H-benzimidazole-2-one (2c), omeprazole mainly to a mixture of 5-methoxy-3H-benzimidazole-2-thione (1a) and 2-hydroxymethyl-3, 5-dimethyl-4-methoxypyridine (1b), and pantoprazole, to 5-difluoromethoxy-3H-benzimidazole-2-thione (3a) and 2-hydroxymethyl-3, 4-dimethoxypyridine (3b). Although some of the degradation products had already been observed under different conditions, the detection of benzimidazole-2-thiones is unprecedented and their involvement as possible physiological, yet toxic antioxidants must be emphasized. Plausible, unified mechanisms for the formation of the different degradation products observed herein and in previous papers from the literature are suggested.
    Mots-clés : ERMMES, MMMAX, POLE 2.

  • M. Raynal, F. Portier, P. W. N. M. van Leeuwen, et L. Bouteiller, « Tunable Asymmetric Catalysis through Ligand Stacking in Chiral Rigid Rods », Journal of the American Chemical Society, vol. 135, nᵒ 47, p. 17687-17690.
    Résumé : Chiral benzene-1,3,5-tricarboxamide (BTA) ligands, comprising one diphenylphosphino group and one or two remote chiral 1-methylheptyl side chains, were evaluated in the rhodium-catalyzed asymmetric hydrogenation of dimethyl itaconate. Despite the fact that the rhodium atom and the chiral center(s) are separated by more than 12 covalent bonds, up to 82% ee was observed. A series of control and spectroscopic experiments confirmed that the selectivity arises from the formation of chiral helical polymers by self-association of the BTA monomers through noncovalent interactions. The addition of a phosphine-free chiral BTA, acting as a comonomer for the chiral BTA ligands, increases the level of enantioselectivity (up to 88% ee). It illustrates how the selectivity of the reaction can be increased in a simple fashion by mixing two different BTA monomers. The concept was further probed by performing the same experiment with an achiral BTA ligand, i.e. a phosphine-functionalized BTA that contains two remote octyl side chains. It afforded an encouraging 31% ee, thus demonstrating the catalytically relevant transfer of chirality between the self-assembled units. It constitutes a unique example of the sergeants-and-soldiers principle applied to catalysis.
    Mots-clés : POLE 4, POLYMERES.

  • G. Reecht, H. Bulou, F. Scheurer, V. Speisser, B. Carrière, F. Mathevet, et G. Schull, « Oligothiophene Nanorings as Electron Resonators for Whispering Gallery Modes », Physical Review Letters, vol. 110, nᵒ 5, p. 056802.
    Résumé : Structural and electronic properties of oligothiophene nanowires and rings synthesized on a Au(111) surface are investigated by scanning tunneling microscopy. The spectroscopic data of the linear and cyclic oligomers show remarkable differences which, to a first approximation, can be accounted by considering electronic state confinement to one-dimensional boxes having, respectively, fixed and periodic boundary conditions. A more detailed analysis shows that polythiophene must be treated as a ribbon (i.e., having an effective width) rather than a purely 1D structure. A fascinating consequence is that the molecular nanorings act as whispering gallery mode resonators for electrons, opening the way for new applications in quantum electronics.
    Mots-clés : POLE 4, POLYMERES.

  • P. Ribagnac, C. Cannizzo, R. Méallet-Renault, G. Clavier, P. Audebert, R. Pansu, et L. Bouteiller, « Fluorescent Labeling of a Bisurea-Based Supramolecular Polymer », The Journal of Physical Chemistry B, vol. 117, nᵒ 6, p. 1958-1966.
    Résumé : Bisurea-based supramolecular polymer 2-ethylhexyl-3-[3-(3-(2-ethylhexyl)ureido)-4-methyl-phenyl]urea (EHUT) has been shown previously to self-assemble through hydrogen bonding into high-molecular-weight structures. The present publication reports the study of the thermodynamics of these tubular structures by time-resolved fluorescence spectroscopy, with the help of a tetrazine labeled monomer. Results of calorimetry and time-resolved fluorescence spectroscopy show that the as-modified monomer EHUTz does not interfere with the formation of the supramolecular assembly. When incorporated, these labeled monomers exhibit a longer fluorescence lifetime due to the electron-rich tolyl group buried in the structure. Dilution experiments allowed us to measure their partition coefficient, and to compare it with the critical aggregation concentration of EHUT. Measurements at higher dye loads, where interactions between neighboring tetrazines occur, show that EHUTz is uniformly dissolved in the supramolecular polymer. Tetrazine dye is a good reporter of events occurring in solution, such as disruption of the assembly upon heating. Our results confirm the pseudophase diagram for EHUT solution in toluene obtained previously with other techniques such as infrared spectroscopy and calorimetry.
    Mots-clés : POLE 4, POLYMERES.

  • B. Riflade, J. Oble, L. Chenneberg, E. Derat, B. Hasenknopf, E. Lacôte, et S. Thorimbert, « Hybrid polyoxometalate palladacycles: DFT study and application to the Heck reaction », Tetrahedron, vol. 69, nᵒ 27–28, p. 5772-5779, 2013.
    Résumé : The phosphovanadotungstate polyanion [P2W15V3O62]9− is a powerful support to stabilize palladacycles conjugated to the inorganic framework via an organic ligand. The insertion can be directed toward sp2 or sp3 C–H insertion upon appropriate choice of the substitution pattern on the organic ligand. DFT modeling indicates that the strong withdrawing effect of the POM transmitted through the conjugated carbonyl was responsible for this easy insertion. The palladacycles led to the formation of stilbene via a Mizoroki–Heck reaction. However it is likely that the POMs act as Pd-reservoirs for the formation of nanoparticles.
    Mots-clés : catalysis, CHEMBIO, COS, C–H insertion, GOBS, Heck reaction, Heterocycles, Hybrid polyoxometalate, MACO, Palladacycles, POLE 1, POLE 3, SSO, SUPRA.

  • C. Rinfray, G. Izzet, J. Pinson, S. Gam Derouich, J. - J. Ganem, C. Combellas, F. Kanoufi, et A. Proust, « Electrografting of Diazonium-Functionalized Polyoxometalates: Synthesis, Immobilisation and Electron-Transfer Characterisation from Glassy Carbon », Chemistry – A European Journal, vol. 19, nᵒ 41, p. 13838–13846.
    Résumé : Polyoxometalates (POMs) are attractive candidates for the rational design of multi-level charge-storage materials because they display reversible multi-step reduction processes in a narrow range of potentials. The functionalization of POMs allows for their integration in hybrid complementary metal oxide semiconductor (CMOS)/molecular devices, provided that fine control of their immobilisation on various substrates can be achieved. Owing to the wide applicability of the diazonium route to surface modification, a functionalized Keggin-type POM [PW11O39Ge(p-C6H4-CC-C6H4-$\rm N+\hfill \atop 2\hfill$)]3− bearing a pending diazonium group was prepared and subsequently covalently anchored onto a glassy carbon electrode. Electron transfer with the immobilised POM was thoroughly investigated and compared to that of the free POM in solution.
    Mots-clés : diazonium grafting, E-POM, electron transfer, electron transport, POLE 2, Polyoxometalates, POM, surface immobilization.

  • P. - J. Roumanet, F. Laflèche, N. Jarroux, Y. Raoul, S. Claude, et P. Guégan, « Novel aliphatic polyesters from an oleic acid based monomer. Synthesis, epoxidation, cross-linking and biodegradation », European Polymer Journal, vol. 49, nᵒ 4, p. 813-822, 2013.
    Résumé :

    rong> The synthesis of polymeric materials based on monomers from renewable feedstocks is a steadily growing field. New aliphatic polyesters derived from the 1,18-(Z)-octadec-9-enedioic acid (D18:1), a high oleic sunflower oil fatty acid derivative, and aliphatic diols of different molecular weight (from 1,3-propanediol to 1,12-dodecanediol) have been synthesized and characterized. The polymerization was undertaken by direct bulk polycondensation of a diacid with a diol, with or without a metal catalyst, leading to viscous liquid to solid semi-crystalline polyesters at room temperature, depending on the diol type. The molecular weights of polyesters ranged between 7000 and 20,000 g mol−1. The main attractive aspects of these polyesters are the renewable biomass origin of the diacid and the presence of double bonds on the polymer backbone (oleic acid derivative) allowing subsequent chemical modifications. The epoxidation of these double bonds was undertaken on the macromolecular chains to induce the photochemical cross-linking of the epoxide functions. Transparent and homogeneous cross-linked films were made by photo-polymerization of the epoxy units with less than 5% of extractible products. Enzymatic degradation of these polyesters (cross-linked) was poor over 8 weeks.
    Mots-clés : Fatty acids derivatives, POLE 4, Poly(ester), POLYMERES, renewable resources.

  • B. Rudolf, M. Salmain, J. Grobelny, G. Celichowski, et M. Cichomski, « Preparation of metallocarbonyl–gold-antibody bioconjugates for mid-IR optical immunosensing », Journal of Organometallic Chemistry, vol. 734, p. 32-37, 2013.
    Résumé : Metallocarbonyl-labeled gold nanoparticles (displaying specific and intense absorption bands assigned to the stretching vibrations of the carbonyl ligands in IR spectroscopy) were derivatized with an anti-mouse IgG antibody to provide IR reporter immunoprobes that were characterized by several analytical techniques like ELISA, IR and transmission electron microscopy (TEM). These immunoprobes were able to detect a mouse monoclonal anti-staphylococcal enterotoxin A (SEA) antibody chemisorbed to a planar gold-coated glass sensor. The formation of the immune complex between metallocarbonyl–gold nanoparticle-antibody bioconjugate and anti-SEA antibody was assessed by mid-IR surface and atomic force microscopy (AFM) analysis.
    Mots-clés : CHEMBIO, gold nanoparticles, Immunoprobes, immunosensors, Metallocarbonyl labels, POLE 3.

  • C. s Allain, D. Schaming, N. Karakostas, M. Erard, J. - P. Gisselbrecht, S. Sorgues, I. Lampre, L. Ruhlmann, et B. Hasenknopf, « Synthesis, electrochemical and photophysical properties of covalently linked porphyrin–polyoxometalates », Dalton Transactions, vol. 42, nᵒ 8, p. 2745-2754.
    Résumé : Two covalently linked porphyrin–polyoxometalate hybrids have been prepared: an Anderson-type hexamolybdate [N(C4H9)4]3[MnMo6O18{(OCH2)3CNHCO(ZnTPP)}2] with two pendant zinc(ii)-tetraphenylporphyrins, and a Dawson-type vanadotungstate [N(C4H9)4]5H[P2V3W15O59{(OCH2)3CNHCO(ZnTPP)}] with one porphyrin. Electroch
    Mots-clés : GOBS, POLE 3, SUPRA.

  • M. - P. Santoni, F. Nastasi, S. Campagna, G. S. Hanan, B. Hasenknopf, et I. Ciofini, « Understanding the redox properties of dinuclear ruthenium(II) complexes by a joint experimental and theoretical analysis », Dalton Transactions, vol. 42, nᵒ 15, p. 5281-5291.
    Résumé : A combined experimental and theoretical approach has been used to investigate the redox properties of two dinuclear Ru(II) complexes, 2a and 2b, containing the planar dpt-ph-dpt bridging ligand (dpt-ph-dpt = 1 '', 4 ''-bis(2,4-dipyrid-2'-yl-1,3,5-triazin-6-yl) benzene). The redox properties of the free bridging ligand and the X-ray structure of 2a have also been reported, together with the X-ray structure of a related mononuclear compound, for comparison purposes. The photophysical processes of 2a and 2b have also been studied by pump-probe transient absorption spectroscopy. Compounds 2a and 2b are able to reversibly collect six and eight electrons, respectively, upon electrochemical reduction at mild potentials (>-2.0 V vs. SCE). A detailed assignment of the various reduction processes to specific subunits of the dinuclear arrays has been made possible by calculation of the HOMOs and LUMOs of native and bireduced species. For example, computation allowed us to clarify the redox behavior of 2b: the first reduction processes of this compound occur at almost coincident potentials, with successive electrons added on the same subunit (namely, the bridging ligand). Charge redistribution towards the other subunits of the molecular framework upon second reduction, revealed by calculation performed on the bireduced species, is the key to interpreting this peculiar behavior. Inter-ligand electron hopping interconverts the MLCT state involving the peripheral ligand to that of the (lower-lying) MLCT state that involves the bridging ligand. This process is faster than 350 fs in 2a, where its driving force is higher than 0.2 eV, whereas it occurs with a time constant of about 6 ps in 2b, having a smaller driving force for the process. Both compounds decay to the ground state, with MLCT emission on the nanosecond time scale, however a faster component of such decay is kinetically evidenced, indicating a process of about 200-250 ps in both cases, which is tentatively assigned to relatively slow diffusive solvent dynamics.
    Mots-clés : absorption-spectra, artificial photosynthesis, electrochemical oxidation, electron-transfer, energy-gap law, GOBS, photocatalytic hydrogen-production, photophysical properties, POLE 3, SUPRA, transfer excited-states, transition-metal-complexes, tridentate ligands.

  • C. Schäffer, A. M. Todea, H. Bögge, S. Floquet, E. Cadot, V. S. Korenev, V. P. Fedin, P. Gouzerh, et A. Müller, « A further step towards tuning the properties of metal-chalcogenide nanocapsules by replacing skeletal oxide by sulphide ligands », Dalton Transactions, vol. 42, nᵒ 2, p. 330-333.
    Résumé : Addition of [Mo2VO2(μ-O)(μ-S)(aq)]2+ linker-type units to a solution/dynamic library containing tungstates results via the formation of the complementary pentagonal {(W)W5} units logically in the self-assembly of a mixed oxide/sulphide {WVI72MoV60}-type Keplerate, thereby demonstrating the ability to tune th
    Mots-clés : building-blocks, capsule, centers, chemistry, clusters, dynamic library, E-POM, keplerate-type, molybdenum-oxide, POLE 2, POM, pores, x-ray structures.

  • A. Schwarzenberg, F. Ichou, R. B. Cole, X. Machuron-Mandard, C. Junot, D. Lesage, et J. - C. Tabet, « Identification tree based on fragmentation rules for structure elucidation of organophosphorus esters by electrospray mass spectrometry », Journal of Mass Spectrometry, vol. 48, nᵒ 5, p. 576-586.
    Résumé : Organophosphorus compounds have played important roles as pesticides, chemical warfare agents and extractors of radioactive material. Structural elucidation of phosphonates poses a particular challenge because their initial forms can be hydrolyzed, thus, degradation products may predominate in samples acquired in the field. The analysis of non-volatile organophosphorus compounds and their degradation products is possible using electrospray tandem mass spectrometry ESI-MS/MS. Here, we present a generic strategy that allows the unambiguous identification of substituents for two families of organophosphorus compounds: the phosphonates and phosphates. General fragmentation rules were deduced based on the study of decomposition pathways of 55 organophosphorus esters, including examples found in the literature. Multistage MS (MSn) experiments at high resolution in a hybrid mass spectrometer provide accurate mass measurements, whereas collision-induced dissociation experiments in a triple quadrupole give access to small fragment ions. The creation of a specific nomenclature for each possible structure of organophosphorus compound, depending on the alkyl side chain linked to the oxygen, was achieved by applying these fragmentation rules. This led to the creation of an identification tree' based upon the unique consecutive decomposition pathways uncovered for each individual compound. Hence, seven structural motifs were created that orient an unequivocal identification using the identification tree'. Despite the similar structures of the ensemble of phosphate and phosphonate esters, distinct identifications based upon characteristic neutral losses and diagnostic fragment ions were possible in all cases. Copyright (c) 2013 John Wiley & Sons, Ltd.
    Mots-clés : chemical warfare agents, CSOB, decontamination solutions, degradation-products, elucidation, fragmentation tree, high resolution, ionization, mass spectrometry, msn, nmr-spectroscopy, organophosphorus, POLE 3, spectral trees, structure.

0 | ... | 500 | 550 | 600 | 650 | 700 | 750 | 800 | 850 | 900 | 950

--- Exporter la sélection au format