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Productions scientifiques

2017, ICR-2010-2017.

ACL - Articles dans des revues à comité de lecture

109 références.

  • Al Mousawi, A.; Dumur, F.; Garra, P.; Toufaily, J.; Hamieh, T.; Goubard, F.; Bui, T. - T.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Journal of Polymer Science Part a-Polymer Chemistry 2017, 55 (7), 1189–1199.
    Résumé : In this article, novel azahelicenes (AZs) were synthesized and proposed as high performance visible light photoinitiators for both the free radical polymerization of acrylates and the cationic polymerization (CP) of epoxides upon visible light exposure using Light Emitting Diodes (LEDs) @405, @455, and @470 nm. Excellent polymerization initiating abilities are found and high final conversions were obtained. Remarkably, an exceptional long lifetime photoluminescence property of the polymer films was observed when synthesized in presence of AZs. A full picture of the involved chemical mechanisms is given. AZs being high performance photoinitiators, their use in new cationic LED 3D printing resins will be also presented, that is, the cationic process upon LED projector @405 nm can be useful to reduce the shrinkage usually observed for radical polymerization. LED projector printing is very interesting compared to laser writing as this technology projects the profile of an entire layer of a 3D object at one time. (c) 2016 Wiley Periodicals, Inc.
    Mots-clés : cationic polymerization, electron, Free radical polymerization, helicenes, initiators, light-emitting diodes, Photochemistry, Photoinitiators, photopolymerization, sensor, water.

  • Al Mousawi, A.; Dumur, F.; Garra, P.; Toufaily, J.; Hamieh, T.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Macromolecules 2017, 50 (7), 2747–2758.
    Résumé : Four new carbazole derivatives (C1-C4) are synthesized and proposed as high performance visible light photoinitiators/photoredox catalysts for both the free radical polymerization (FRP) of (meth)acrylates and the cationic polymerization (CP) of epoxides upon visible light exposure using light-emitting diodes (LEDs) at 405, 455, and 477 nm. Excellent polymerization initiating abilities are found, and high final reactive function conversions are obtained. Interestingly, these new derivatives exhibit much better visible light polymerization initiating ability compared to a reference UV-absorbing carbazole (CARET, 9H-carbazole-9-ethanol) showing that the new substituents are of great interest to red-shift the absorption of the proposed photoinitiators. More remarkably, in combination with an iodonium salt, C1-C4 are also better than the well-known bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (BAPO) photoinitiator for mild irradiation conditions highlighting their outstanding reactivity. Their use in new cationic resins for LED projector 3D printing is particularly outlined. A full picture of the involved photochemical mechanisms is provided. Originally, these carbazoles behave as metal-free photoredox catalysts active in both oxidative and reductive cycles.
    Mots-clés : atom-transfer, cationic-polymerization, n-vinylcarbazole, Photocatalysts, photopolymerization, transfer radical polymerization, visible-light.

  • Al Mousawi, A.; Garra, P.; Dumur, F.; Bui, T. - T.; Goubard, F.; Toufaily, J.; Hamieh, T.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Molecules 2017, 22 (12), 2143.
    Résumé : Radical chemistry is a very convenient way to produce polymer materials. Here, an application of a particular photoinduced radical chemistry is illustrated. Seven new carbazole derivatives Cd1-Cd7 are incorporated and proposed as high performance near-UV photoinitiators for both the free radical polymerization (FRP) of (meth)acrylates and the cationic polymerization (CP) of epoxides utilizing Light Emitting Diodes LEDs @405 nm. Excellent polymerization-initiating abilities are found and high final reactive function conversions are obtained. Interestingly, these new derivatives display much better near-UV polymerization-initiating abilities compared to a reference UV absorbing carbazole (CARET 9H-carbazole-9-ethanol) demonstrating that the new substituents have good ability to red shift the absorption of the proposed photoinitiators. All the more strikingly, in combination with iodonium salt, Cd1-Cd7 are likewise preferred as cationic photoinitiators over the notable photoinitiator bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (BAPO) for mild irradiation conditions featuring their remarkable reactivity. In particular their utilization in the preparation of new cationic resins for LED projector 3D printing is envisioned. A full picture of the included photochemical mechanisms is given.
    Mots-clés : 3D printing, cationic polymerization, cationic-polymerization, Free radical polymerization, light emitting diodes (LEDs), Photoinitiators, resins, systems, transfer radical polymerization, visible-light.

  • Al Mousawi, A.; Kermagoret, A.; Versace, D. - L.; Toufaily, J.; Hamieh, T.; Graff, B.; Dumur, F.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Polymer Chemistry 2017, 8 (3), 568–580.
    Résumé : Copper complexes (CuCs) bearing pyridine-pyrazole ligands are synthesized and evaluated as new photoredox catalysts/photoinitiators in combination with an iodonium salt (Iod) for the free radical polymerization of (meth) acrylates and the cationic polymerization of epoxides upon visible light exposure using a Light Emitting Diode (LED)@405 nm. The structure/reactivity/efficiency relationships for the copper complexes are studied as well as the chemical mechanisms involved. The different substituents on the pyrazole moiety of the ligand allow tuning of the oxidation potential and the visible light absorbance of the complexes and to optimize the performance of the polymerization photoredox catalysts. The use of a novel additive (CARET) in a three-component system (CuC/Iod/CARET) highly improves the performance. Finally, the high performances of the Cu(I) complexes for the development of new 3D printing resins using an LED projector are demonstrated. Currently, LED projector printing is really advantageous in 3D printing i.e. this technology projects the profile of an entire layer at one time.
    Mots-clés : atom-transfer, click reactions, coordination-compounds, cu(i) complexes, cu-based sensitizers, emitting electrochemical-cells, iridium complexes, oxygen tolerance, pet-raft polymerization, transfer radical polymerization.

  • Al Mousawi, A.; Lara, D. M.; Noirbent, G.; Dumur, F.; Toufaily, J.; Hamieh, T.; Buo, T. - T.; Goubard, F.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Macromolecules 2017, 50 (13), 4913–4926.
    Résumé : This paper is devoted to the effect of a thermally activated delayed fluorescence (TADF) property in new photoinitiators/photoredox catalysts. Four carbazole derivatives A1-A4 exhibiting a TADF character are synthesized and proposed for the first time as high performance visible light photoinitiators/metal-free photoredox catalysts, in the presence of an amine or/and an iodonium salt, for both the free radical polymerization (FRP) of (meth)acrylates and the cationic polymerization (CP) of epoxides upon visible light exposure using light-emitting diodes (LEDs) at 405, 455, and 477 nm. Interestingly, the impact of the substituent effect on the excited state lifetimes and therefore on the photoinitiating ability of a series of substituted carbazoles was clearly evidenced and examined. Upon bromination of the carbazole core, clear effects on the excited state lifetimes and light absorption were demonstrated, enabling to tune the initiator performance. Excellent polymerization initiating abilities are found, and high final monomer conversions are obtained. The use of these novel carbazole-based systems in photocurable cationic formulations for LED projector 3D printing is particularly outlined. TADF molecules allow a more efficient reaction from the excited singlet state as a result of their prolonged lifetimes; i.e., this effect is well highlighted through a comparison with previously published none-TADF metal-free photoredox catalysts. A full picture of the involved photochemical mechanisms is also provided. Carbazoles exhibiting a TADF character pave the way toward metal-free photoredox catalysts active in both oxidative and reductive cycles with efficiency on par with those of the traditional metal-based photoredox catalysts/photoinitiators.
    Mots-clés : fluorophores, n-vinylcarbazole, photoinitiating systems, photopolymerization, promoted cationic-polymerization, resins, uv, visible-light.

  • Al Mousawi, A.; Poriel, C.; Dumur, F.; Toufaily, J.; Hamieh, T.; Fouassier, J. P.; Lalevee, J. Macromolecules 2017, 50 (3), 746–753.
    Résumé : Zinc tetraphenylporphyrin (ZnTPP) is proposed as a high performance visible light photoinitiator for both the free radical polymerization (FRP) of methacrylates (thick films) and the cationic polymerization (CP) of epoxides (thin films) upon visible light exposure using light emitting diodes (LEDs) at 405, 455, 477, and S30 nm. ZnTPP combined with an iodonium salt shows excellent polymerization initiating abilities and high final conversions were obtained. Remarkably, for the ligand alone (tetraphenylporphyrin derivative, H2TPMP) used as photoinitiator, no polymerization occurs, indicating the importance of the metal in the initiating complex for an efficient process. A full picture of the involved chemical mechanisms is given. The high performance of ZnTPP as cationic initiating system is also well shown for new cationic 3D printing resins upon exposure to LED projector at 405 nm.
    Mots-clés : atom-transfer, copper, electron, porphyrins, systems, transfer radical polymerization.

  • Al Ouahabi, A.; Amalian, J. - A.; Charles, L.; Lutz, J. - F. Nature Communications 2017, 8, 967.
    Résumé : In the context of data storage miniaturization, it was recently shown that digital information can be stored in the monomer sequences of non-natural macromolecules. However, the sequencing of such digital polymers is currently limited to short chains. Here, we report that intact multi-byte digital polymers can be sequenced in a moderate resolution mass spectrometer and that full sequence coverage can be attained without requiring pre-analysis digestion or the help of sequence databases. In order to do so, the polymers are designed to undergo controlled fragmentations in collision-induced dissociation conditions. Each byte of the sequence is labeled by an identification tag and a weak alkoxyamine group is placed between 2 bytes. As a consequence of this design, the NO-C bonds break first upon collisional activation, thus leading to a pattern of mass tag-shifted intact bytes. Afterwards, each byte is individually sequenced in pseudo-MS3 conditions and the whole sequence is found.
    Mots-clés : chemistry, defined polymers, DNA, efficient, information-storage, macromolecules, oligonucleotides, phosphoramidite, robust.

  • Alezra, V.; Wan, Y.; Auberger, N.; Thétiot-Laurent, S.; Bouillère, F.; Zulauf, A.; He, J.; Courtiol-Legourd, S.; Guillot, R.; Kouklovsky, C.; Cote des Combes, S.; Pacaud, C.; Devillers, I. European Journal of Organic Chemistry 2017.
    Résumé : We describe here an efficient synthesis of both diastereomers of cyclic b,g-diamino acids starting from L-glutamic acid based on Blaise reaction. We showed that by changing the protecting group, we could have access to either 5-member ring lactam, which can be used as b-amino acid, or to 6-member ring lactam, as g-amino acid. We also discovered an interesting kinetic resolution during the synthesis which allowed easier diastereomer separation. These compounds can be easily used in peptide synthesis and a tetramer alternating trans cyclic g-amino acid and AIB has been synthesized.

  • Amalian, J. - A.; Al Ouahabi, A.; Cavallo, G.; Konig, N. F.; Poyer, S.; Lutz, J. - F.; Charles, L. Journal of Mass Spectrometry 2017, 52 (11), 788–798.
    Résumé : Digital polymers are monodisperse chains with a controlled sequence of co-monomers, defined as letters of an alphabet, and are used to store information at the molecular level. Reading such messages is hence a sequencing task that can be efficiently achieved by tandem mass spectrometry. To improve their readability, structure of sequence-controlled synthetic polymers can be optimized, based on considerations regarding their fragmentation behavior. This strategy is described here for poly(phosphodiester)s, which were synthesized as monodisperse chains with more than 100units but exhibited extremely complex dissociation spectra. In these polymers, two repeating units that differ by a simple H/CH3 variation were defined as the 0 and 1bit of the ASCII code and spaced by a phosphate moiety. They were readily ionized in negative ion mode electrospray but dissociated via cleavage at all phosphate bonds upon collisional activation. Although allowing a complete sequence coverage of digital poly(phosphodiester)s, this fragmentation behavior was not efficient for macromolecules with more than 50 co-monomers, and data interpretation was very tedious. The structure of these polymers was then modified by introducing alkoxyamine linkages at appropriate location throughout the chain. A first design consisted of placing these low dissociation energy bonds between each monomeric bit: while cleavage of this sole bond greatly simplified MS/MS spectra, efficient sequencing was limited to chains with up to about 50units. In contrast, introduction of alkoxyamine bonds between each byte (i.e. a set of eight co-monomers) was a more successful strategy. Long messages (so far, up to 8 bytes) could be read in MS3 experiments, where single-byte containing fragments released during the first activation stage were further dissociated for sequencing. The whole sequence of such byte-truncated poly(phosphodiester)s could be easily re-constructed based on a mass tagging system which permits to determine the original location of each byte in the chain. Copyright (c) 2017 John Wiley & Sons, Ltd.
    Mots-clés : collision-induced dissociation, containing macromolecules, Digital polymers, DNA, encoded poly(alkoxyamine amide)s, fragmentation, information storage, molecular design, ms, MS sequencing, nucleic-acids, phosphoramidite chemistry, polymers, polyphosphates, proteomics, sequence-controlled polymers, storage, tandem mass-spectrometry.

  • Amalian, J. - A.; Poyer, S.; Petit, B. E.; Telitel, S.; Monnier, V.; Karamessini, D.; Gigmes, D.; Lutz, J. - F.; Charles, L. International Journal of Mass Spectrometry 2017, 421, 271–278.
    Résumé : MS/MS sequencing is an unrivaled technique to decipher binary information chemically encoded in the backbone of sequence-controlled synthetic polymers constructed with two co-monomers of different mass, arbitrarily designated as the 0- and 1-bit of the ASCII alphabet. Efficiency of this "reading" step relies however on the simplicity of MS/MS patterns, which depends on both polymer chemistry and chain length. In this context, polyurethanes (PUs) were very promising candidates as dissociation of small deprotonated oligomers (n \textless 8) yielded a single fragment series. The carbamate bond cleavage reaction was hence studied in details to tentatively anticipate the CID behavior of longer chains prior to optimizing their synthesis. In spite of the simplicity of MS/MS spectra, three different mechanisms were evidenced; however, they were not expected to induce MS/MS complexity when activating longer chains, as verified for sequence-controlled PUs containing up to two bytes of information (i.e., 16 co-monomers). In contrast, the ionization step appeared to be an issue: deprotonation yield of the end-group in negative ion mode electrospray was observed to strongly decrease as PU chain length increases. This sensitivity issue was addressed by introducing a second acidic end-group to allow doubly deprotonated oligomers with no impact on their CID behavior. (C) 2017 Elsevier B.V. All rights reserved.
    Mots-clés : Carbamate bond cleavage, collision-induced dissociation, containing macromolecules, Digital polymers, DNA, mass-spectrometry, MS/MS sequencing, phosphoramidite, polymers, Polyurethanes, sequence-controlled polymers, storage.

  • Andre-Barres, C.; Carissan, Y.; Tuccio, B. Acs Omega 2017, 2 (9), 5357–5363.
    Résumé : Mechanism of the addition of molecular oxygen on the dienolic form of the 2-alkylidene-1,3-cyclohexadione was investigated by quantum chemical calculations using the approximate projection method developed by Yamaguchi. The complete reaction pathway of the formation of the endoperoxide is described. The crossing between triplet and singlet potential energy surfaces has been located. A multireference complete active space self-consistent field calculation has been performed to strengthen the results.
    Mots-clés : density, peroxides.

  • Anselmi, C.; Capitani, D.; Tintaru, A.; Doherty, B.; Sgamellotti, A.; Miliani, C. Dyes and Pigments 2017, 140, 297–311.
    Résumé : Motivated by the fugitive and undisclosed nature of eosin-derived pigments as used by Vincent van Gogh, this paper presents the syntheses of monometallic and historical bimetallic eosin-based lakes and structural elucidation by MS, ATR-FTIR and NMR. Specifically two monometallic (Al, Pb) and several bimetallic lakes (on varying Al and Pb constituents) have been synthesized and examined alongside two reference compounds: eosin disodium salt and eosin Y. Resulting monometallic lake complexes are 2:1 adducts (dye:metal) with the carboxylic group coordinating the metal. In historical lake preparations, no correlation between the coordinating metals and the resulting lake color can be made. On production and investigations of different eosin lake substrates, two main anchored species have been distinguished: H-bonded for eosin onto Pb-substrates and a further bridged bidentate for eosin onto alumina. A prominent tendency to form 2:1 eosin:Pb adducts emerged in each Pb-containing recipe. Evidence concerning historical lakes suggests that eosin can diversely coordinate to metals thus producing a variety of nuances in according to experimental pH and reaction conditions. This behavior may well explain observed discrepancies between historical recipes and experimental findings regarding the coordination of eosin to one or more metals. (C)2017 Elsevier Ltd. All rights reserved.
    Mots-clés : angle-spinning nmr, assisted-laser-desorption/ionization, atr-ftir, Carboxylate anchorage, cross-polarization, degradation process, lead chromate, mas-nmr, paintings, Solid state NMR s, spectroscopy, van Gogh's pigments, vincent van gogh, Xanthene dyes, yellow.

  • Audran, G.; Adiche, C.; Bremond, P.; El Abed, D.; Hamadouche, M.; Siri, D.; Santelli, M. Tetrahedron Letters 2017, 58 (10), 945–948.
    Résumé : Enamines derived from cyclic ketones react with arenesulfonyl azides and cyanogen azide, mainly via ring contraction, with formation of the corresponding amidines. The mechanism of this efficient rearrangement, which has not been investigated experimentally, was determined with the aid of quantum-chemical calculations. In the transition state, from the intermediate 5-amino-v-triazolines, the loss of dinitrogen and a cyclic rearrangement occurred in one-step in a quite synchronous manner with a very low transition state energy.
    Mots-clés : 1, 2, 3-dipolar cycloadditions, 3-triazoles, Amidines, Azides, cascade, catalyst, chemistry, derivatives, Enamines, huisgen cycloaddition, ketones, organic azides, Quantum chemical calculations, Ring contraction, upsilon-triazolines.

  • Audran, G.; Bagryanskaya, E.; Bagryanskaya, I.; Edeleva, M.; Marque, S. R. A.; Parkhomenko, D.; Tretyakov, E.; Zhivetyeva, S. Chemistryselect 2017, 2 (12), 3584–3593.
    Résumé : A series of Zn(hfac)(2) alkoxyamines (diethyl(2,2-dimethyl-1-(tert-butyl-(1-pyridylethoxy)amino)propyl)phosphonate) coordinated at ortho, meta and para positions of their pyridyl moiety were prepared and their homolysis rate constants k(d) measured. Up to a 30-fold increase in k(d) was observed for the meta-(Zn-RR/SS) and para-(Zn-RR/SS) regioisomers. Moreover, the activation is also controlled by the amount of pyridine, used as a ligand competitor. XRD, H-1 and P-31 NMR spectra show very different structures for each complexes in solid state and in solution depending on the diastereosiomers and on the regioisomers.
    Mots-clés : activation, alkoxyamines, C-ON bond homolysis, Nitroxide-mediated polymerization, on bond homolysis, polymers, quaternization, rate enhancement, Zn(hfac)(2) complexes.

  • Audran, G.; Bagryanskaya, E.; Edeleva, M.; Marque, S. R. A.; Yamasaki, T. Rsc Advances 2017, 7 (9), 4993–5001.
    Résumé : Dual initiators for controlled radical/ionic polymerization reactions attract much attention in terms of preparation of new materials. We studied the potential of dual-initiator alkoxyamines 3 [based both on para-substituted aromatic ring for external triggering or initiation of orthogonal polymerization and on N-tert-butyl-N-(1-diethylphosphono-2,2-dimethylpropyl) nitroxide (SG1)] for nitroxide-mediated polymerization (NMP) with various monomers such as styrene, styrene sulphonate, 2-vinyl pyridine or methylmethacrylate. Alkoxyamines 3 were found to be as efficient in the NMP process as N-(2-methylpropyl)- N-(1-diethylphosphono-2,2-dimethylpropyl)-O-(2-carboxylprop-2-yl) hydroxylamine (1). Furthermore, in sharp contrast to 1, alkoxyamines 3 were easier to functionalize.
    Mots-clés : acid, fragmentation chain transfer, free-radical polymerization, living cationic-polymerization, macromolecular architectures, methyl-methacrylate, Nitroxide-mediated polymerization, on bond homolysis, sg1-based alkoxyamines, temperature.

  • Audran, G.; Bagryanskaya, E.; Edeleva, M.; Marque, S. R. A.; Yamasaki, T. Rsc Advances 2017, 7 (42), 25891–25891.

  • Audran, G.; Bikanga, R.; Bremond, P.; Edeleva, M.; Joly, J. - P.; Marque, S. R. A.; Nkolo, P.; Roubaud, V. Organic & Biomolecular Chemistry 2017, 15 (39), 8425–8439.
    Résumé : Recent amazing results (Nkolo et al., Org. Biomol. Chem., 2017, 6167) on the effect of solvents and polarity on the C-ON bond homolysis rate constants kd of alkoxyamine R1R2NOR3 led us to re-investigate the antagonistic effect of intramolecular hydrogen-bonding (IHB) on kd. Here, IHB is investigated both in the nitroxyl fragment R1R2NO and in the alkyl fragment R-3, as well as between fragments, that is, the donating group on the alkyl fragment and the accepting group on the nitroxyl fragment, and conversely. It appears that IHB between fragments (inter IHB) strikingly decreases the homolysis rate constant kd, whereas IHB within the fragment (intra IHB) moderately increases kd. For one alkoxyamine, the simultaneous occurrence of IHB within the nitroxyl fragment and between fragments is reported. The protonation effect is weaker in the presence than in the absence of IHB. A moderate solvent effect is also observed.
    Mots-clés : chemistry, constants, derivatives, family, free-radical polymerization, nitroxyl fragment, polar.

  • Audran, G.; Bikanga, R.; Bremond, P.; Joly, J. - P.; Marque, S. R. A.; Nkolo, P. Journal of Organic Chemistry 2017, 82 (11), 5702–5709.
    Résumé : The design of new R1R2NOR3 alkoxyamines for various applications relies on the accurate prediction of two kinetic parameters, the C-ON bond homolysis rate constant (k(d)) and its re-formation rate constant (k(c)). Relationships to describe the steric and polar effects of the R1R2NO fragment ruling k(d) have been developed. For all cyclic nitroxyl fragments, the steric effect is described as the sum of the bulkiness of the R-1 and R-2 groups (i.e., normal steric effect), while for the noncyclic nitroxyl fragment (except for one case), a leveled steric effect is assumed. In this work, we show that the normal steric effect also applies to noncyclic nitroxyl fragments and that for one case an enhanced steric effect is also observed, i.e., experimental k(d) \textgreater 5-fold larger than the predicted value.
    Mots-clés : bearing, family, free-radical polymerization, mediated polymerization, on bond homolysis, polar, polymers, rate-constant, styrene.

  • Audran, G.; Bremond, P.; Marque, S. R. A.; Santelli, M. Tetrahedron 2017, 73 (25), 3492–3496.
    Résumé : Sulfur is one of the most necessary biogenic elements in nature that must be assimilated by all organisms; it is an essential macronutrient for living organisms and has multiple roles in plant development. The oxidation of elemental sulfur is a complex process involving the contact of cells with sulfur particles, the oxidation of sulfur to sulfite, and the oxidation of sulfite to sulfate. To provide hypothesis concerning the most probable processes in the early states, we determined, by quantum-chemical calculations, the energies of some allotropic forms containing up to 32-40 sulfur atoms and energetics of their reactions with triplet dioxygen. The most probable reactions occurred with methylpolysulfane anions with an electron transfer to give the superoxide anion radical (and thiyls radicals) and especially the formation of peroxydic polysulfane anions. Calculations confirmed that the triplet diradical is more stable than the singlet one for acyclic polysulfide chains. (C) 2017 Elsevier Ltd. All rights reserved.
    Mots-clés : base-catalyzed oxidation, batteries, Diradical sulfur chains, elemental sulfur, metabolism, oxidizing enzyme, Polysulfur derivatives, Quantum-chemical calculations, radical-anions, ray-absorption spectroscopy, rich oxides sno, Sulfur metabolism, sulfur oxygenase-reductase, Super oxide anion radical, thiobacillus-thiooxidans cells.

  • Bai, S.; Barbatti, M. Physical Chemistry Chemical Physics 2017, 19 (20), 12674–12682.
    Résumé : Singlet oxygen production upon photosensitization plays a critical role in drugs based on thionucleobases. While for immunosuppressants its yield must be near zero, for phototherapeutic drugs it should be near the unity. In this work, we apply high-level quantum chemical modelling to investigate the decay of the triplet state of thionucleobases, a main determinant of the singlet oxygen yield. Working on CASPT2 optimizations of two prototypical thiothymines (2-thiothymine and 6-aza-2-thiothymine), we showed that the T-1 state is characterized by two pi pi* minima and by the intersection of T-1 with the singlet ground state. On the basis of this topography, we propose a two-step mechanistic model, which, depending on the energetic balance between the two minima, may have as a determining step either a slow transition between minima or a faster intersystem crossing to S-0. Chemical kinetics modelling, as well as simulations of the transient absorption spectra, confirmed that the two-step model can explain the experimental results available for both molecules. Moreover, through additional investigations of 2-thiocytosine and 6-thioguanine, we show that such a T-1 topography is a common theme for nucleobases. We also discuss how the triplet-state topography may be used to control the singlet oxygen yield, aiming at different medical applications.
    Mots-clés : 2-thiouracil, 4-thiothymidine, 6-thioguanine, conical intersections, DNA, excited-state, picture, population, relaxation, uva.

  • Bai, S.; Barbatti, M. Journal of Chemical Theory and Computation 2017, 13 (11), 5528–5538.
    Résumé : Photosensitized singlet oxygen generation occurring in a PS-O-2 complex, where PS is a photosensitizer chromophore, is a weakly coupled intermolecular energy-transfer process, a still challenging problem for theoretical chemistry. To investigate the reaction rate directly from quantum-chemical calculations, we built a semiclassical kinetic model that minimizes the computational effort for the calculation of diabatic couplings, activation energies, and reorganization energies, which are the components of the rate. The model splits the system into sets of orthogonal coordinates, which are then explored to compute the reaction rate. This model offers an effective way to evaluate the reaction probability of singlet oxygen generation along different directions and intramolecular distances of the PS-O-2 complex. The model can also be applied to other similar intermolecular energy-transfer problems, to connect the reaction kinetics and quantum-chemical calculations.
    Mots-clés : cation, couplings, electron-transfer, energy-transfer, fission, generation, master equation methods, population, systems, triplet-states.

  • Bai, S.; Barbatti, M. Journal of Physical Chemistry Letters 2017, 8 (21), 5456–5460.
    Résumé : First-principles quantum-chemical description of photosensitized singlet oxygen generation kinetics is challenging because of the intrinsic complexity of the underlying triplet fusion process in a floppy molecular complex with open-shell character. With a quantum-chemical kinetic model specifically tailored to deal with this problem, the reaction rates are investigated as a function of intermolecular incidence direction, orientation, and distance between O-2 and the photosensitizer. The adopted photosensitizer, 6-azo-2-thiothymine, combines practical interest and prototypical variability. The study quantitatively determined maximum singlet oxygen generation rates for 15 incidence/orientation directions, showing that they span 5 orders of magnitude between the largest and the smallest rate. Such information may provide a hands-on guideline for the experimental molecular design of new photosensitizers as well as further higher-level theoretical research.
    Mots-clés : 6-thioguanine, absorption, charge-transfer, deactivation, energy, generation, molecular-oxygen, population, rate constants, state.

  • Benyahia, Z.; Dussault, N.; Cayol, M.; Sigaud, R.; Berenguer-Daize, C.; Delfino, C.; Tounsi, A.; Garcia, S.; Martin, P. - M.; Mabrouk, K.; Ouafik, L. 'H. Oncotarget 2017, 8 (9), 15744–15762.
    Résumé : Tumor- or cancer-associated fibroblasts (TAFs or CAFs) are active players in tumorigenesis and exhibit distinct angiogenic and tumorigenic properties. Adrenomedullin (AM), a multifunctional peptide plays an important role in angiogenesis and tumor growth through its receptors calcitonin receptor-like receptor/receptor activity modifying protein -2 and -3 (CLR/RAMP2 and CLR/RAMP3). We show that AM and AM receptors mRNAs are highly expressed in CAFs prepared from invasive breast carcinoma when compared to normal fibroblasts. Immunostaining demonstrates the presence of immunoreactive AM and AM receptors in the CAFs (n = 9). The proliferation of CAFs is decreased by anti-AM antibody (alpha AM) and antiAM receptors antibody (aAMR) treatment, suggesting that AM may function as a potent autocrine/paracrine growth factor. Systemic administration of aAMR reduced neovascularization of in vivo Matrigel plugs containing CAFs as demonstrated by reduced numbers of the vessel structures, suggesting that AM is one of the CAFs-derived factors responsible for endothelial cell-like and pericytes recruitment to built a neovascularization. We show that MCF-7 admixed with CAFs generated tumors of greater volume significantly different from the MCF-7 xenografts in nude mice due in part to the induced angiogenesis. aAMR and AM(22-52) therapies significantly suppressed the growth of CAFs/MCF-7 tumors. Histological examination of tumors treated with AM(22-52) and aAMR showed evidence of disruption of tumor vasculature with depletion of vascular endothelial cells, induced apoptosis and decrease of tumor cell proliferation. Our findings highlight the importance of CAFs-derived AM pathway in growth of breast carcinoma and in neovascularization by supplying and amplifying signals that are essential for pathologic angiogenesis.
    Mots-clés : adrenomedullin, autocrine manner, breast cancer, cell-lines, cross-talk, differentiation, expression, in-vitro, invasion, microenvironment, myofibroblast, myofibroblasts, pancreatic-cancer, tgf-beta, tumor growth.

  • Berta, M.; Maria, S.; Phan, T. N. T.; Gigmes, D.; Fina, A.; Camino, G. Journal of Polymer Engineering 2017, 37 (1), 21–30.
    Résumé : Epoxy resin/montmorillonite nanocomposites were obtained via in situ intercalative polymerisation. The polymer matrix consists of anhydride-cured epoxy, and the choice of catalyst allows exchange reactions without depolymerisation. This makes the resin insoluble and reprocessable at the same time and potentially recyclable. In this study, reprocessing of the nanocomposites was done by mechanical grinding and re-welding by compression moulding at high temperature, similarly to thermoplastics. The effect of this process on the level of clay dispersion is discussed. Nanocomposite superstructures were imaged by means of transmission electron microscopy, and montmorillonite interlayer spacings were estimated by small angle X-ray scattering. The thermomechanical and combustion properties of the nanocomposites were investigated by means of dynamic mechanical thermal analysis, thermogravimetric analysis and cone calorimetry. The material tensile complex modulus E* was improved by nanocomposite formation, also after the glass transition occurred. Flammability of the material was moderately affected by the dispersed clay.
    Mots-clés : clay nanocomposites, epoxy, exfoliation, fire, montmorillonite, nanocomposite, polymer nanocomposites, thermosets, transesterification, vitrimer.

  • Biyogo, A. M.; Curti, C.; El-Kashef, H.; Khoumeri, O.; Terme, T.; Vanelle, P. Rsc Advances 2017, 7 (1), 106–111.
    Résumé : Manganese(III) acetate-mediated peroxycyclization between 2-hydroxy-3-methylnaphthoquinone and various alkenes was performed to obtain dihydronaphtho[2,3-c][1,2] dioxine-5,10(3H, 10aH)-diones. The reactivity of symmetrical or unsymmetrical 1,1-disubstituted alkenes and monosubstituted alkenes allowed the synthesis of more than 50 original molecules. Focusing on the excellent reactivity of 2-hydroxy-3-methylnaphthoquinone, we describe the first example of Mn(OAc)(3) reactivity with nitro-substituted alkenes. The scope, limitations and stereochemistry of the products synthesized are discussed. Starting from monosubstituted alkenes, the instability of a pair of diastereoisomers was observed, leading to ring opening.
    Mots-clés : 1, 1-disubstituted alkenes, 2+2+2 cycloaddition, antimalarial, cyclic peroxides, derivatives, endoperoxides, in-vitro activity, manganese(iii) acetate, molecular-oxygen, plasmodium-falciparum.

  • Bloch, E.; Besson, E.; Queyroy, S.; Llewellyn, R.; Gastaldi, S.; Llewellyn, P. L. Acs Applied Materials & Interfaces 2017, 9 (16), 14490–14496.
    Résumé : As the search for functionalized materials for CO2 capture continues, the role of theoretical chemistry is becoming more and more central. In this work, a strategy is proposed where ab initio calculations are compared and validated by adsorption microcalorimetry experiments for a series of, so far unexplored, functionalized SBA-15 silicas with different spacers (aryl, alkyl) and terminal functions (N-3, NO2). This validation then permitted to propose the use of a nitro-indole surface functionality. After synthesis of such a material the predictions were confirmed by experiment. This confirms that it is possible to fine-tune CO2-functional interactions at energies much lower than those observed with amine species.
    Mots-clés : adsorbent, carbon dioxide, co2 capture, design, frameworks, functionalized mesoporous silica, gas-adsorption, in silico design, microcalorimetry, sba-15, separation, sorbents, sorption, zeolites.

  • Bosco, L.; Butscher, T.; Marque, S. R. A. Applied Magnetic Resonance 2017, 48 (4), 379–406.
    Résumé : Recently, we reported a significant solvent effect on the phosphorus hyperfine coupling constant a (P) in beta-phosphorylated 6-membered ring nitroxides (a dagger a (P) = 24 G in Org. Biomol. Chem. 2015). Thus, it led us to investigate the effect of solvent for several 6-membered ring nitroxides. Although smaller than mentioned above, a change of 5-7 G in a (P) with the polarity of solvent was still observed for these nitroxides. As for other beta-phosphorylated nitroxides, a (N) increases with the polarity/polarizability pi* and the Hydrogen Bond Donating alpha properties of the solvent whereas a (P) exhibits the reverse trends. The change of a (P) with the solvent depends a lot on a subtle interplay between the destabilizing steric hindrance due to the bulkiness of the substituents and the stabilizing hyperconjugation interactions SOMO -\textgreater sigma*(C-P) between the anti-bonding orbitals of the C-P bond and the SOMO.
    Mots-clés : aminoxyl radicals, esr, fragment, homolysis rate-constant, nitrogen, probe, resonance.

  • Bouzrati-Zerelli, M.; Frigoli, M.; Dumur, F.; Graff, B.; Fouassier, J. P.; Lalevee, J. Polymer 2017, 124, 151–156.
    Résumé : Two new near-UV and visible-light-sensitive photobase generators (PBGs) are synthesized and investigated. They are built on a near-UV and visible light sensitive (E)-3-(2,2'-bithiophen-5-yl)-2-cyanoacrylic acid chromophore and a latent strong base such as 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD). Upon irradiation, decarboxylation occurs and the base is released. The anionic curing of epoxy/thiol as well as thiol/divinylsulfone formulations in the presence of these PBGs under LEDs at 385 and 405 nm is studied. More than 60% of conversion of the thiol and epoxy functions is achieved upon LED@385 nm without any post baking. (C) 2017 Elsevier Ltd. All rights reserved.
    Mots-clés : acid, ammonium-salts, Photobase generator, photochemical generation, Photochemistry, photodecarboxylation, Photoinitiator, Photoinitiators, photopolymerization, photoreactive materials, Polymerization, superbases.

  • Bouzrati-Zerelli, M.; Zivic, N.; Dumur, F.; Gigmes, D.; Graff, B.; Fouassier, J. P.; Lalevee, J. Polymer Chemistry 2017, 8 (13), 2028–2040.
    Résumé : Eleven diketo pyrrolo-pyrrole (DKPP) derivatives have been synthesized as new high performance photo-initiators and combined with various additives to initiate the free radical polymerization of methacrylates in thin and thick films under visible violet, blue, green, and yellow light irradiation (e.g. LEDs at 405 nm, 470 nm, 477 nm, 520 nm or 565 nm) both in laminate or under air; under red light (@ 635 nm), their performance is lower. Compared to the well-known camphorquinone or Eosin based systems, most of the novel DKPP based photoinitiating systems exhibit much higher efficiencies. The photopolymerization of thick films (1.4 mm) under air is also feasible. Most of these DKPP structures exhibited excellent bleaching properties and can also be used in water-borne formulations. The photochemically generated reactive species have been investigated by steady state photolysis, cyclic voltammetry, fluorescence, laser flash photolysis and electron spin resonance spin trapping techniques.
    Mots-clés : cationic-polymerization, challenges, diketopyrrolopyrrole, efficient, electron, films, long-wavelength photosensitizer, multicolor photoinitiator, thiophene derivatives, Visible lights.

  • Burel, A.; Carapito, C.; Lutz, J. - F.; Charles, L. Macromolecules 2017, 50 (20), 8290–8296.
    Mots-clés : DNA, information, macromolecules, phosphoramidite, poly(alkoxyamine amide)s, synthetic-polymers, tandem mass-spectrometry.

  • Carissan, Y.; Nava, P.; Tuccio, B.; Commeiras, L.; Parrain, J. - L. Physical Chemistry Chemical Physics 2017, 19 (4), 3409–3413.
    Résumé : The proposal and the comments made by Korth et al. on a biradical intermediate along the isomerization path of the reaction of trans-1,2-tert-butyldimethyldisilyloxybenzocyclobutene 1 with dioxygen are unsuitable in our case. The mechanism scenario that we proposed is in agreement with our experimental observations. Moreover, new calculations were able to give an answer to the crucial question, "is the biradical an intermediate or a transition state?” together with the localization of the two radicals. This full article is a response to the "Comment on "trans-1,2-Disiloxybenzocyclobutene, an adequate partner for the auto-oxidation: EPR/spin trapping and theoretical studies” by J. Drujon et al., Phys. Chem. Chem. Phys. 2014, 16, 7513”.
    Mots-clés : approximation, diels-alder cycloadditions, multireference perturbation-theory, valence.

  • Charles, L.; Cavallo, G.; Monnier, V.; Oswald, L.; Szweda, R.; Lutz, J. - F. Journal of the American Society for Mass Spectrometry 2017, 28 (6), 1149–1159.
    Résumé : In order to improve their MS/MS sequencing, structure of sequence-controlled synthetic polymers can be optimized based on considerations regarding their fragmentation behavior in collision-induced dissociation conditions, as demonstrated here for two digitally encoded polymer families. In poly(triazole amide)s, the main dissociation route proceeded via cleavage of the amide bond in each monomer, hence allowing the chains to be safely sequenced. However, a competitive cleavage of an ether bond in a tri(ethylene glycol) spacer placed between each coding moiety complicated MS/MS spectra while not bringing new structural information. Changing the tri(ethylene glycol) spacer to an alkyl group of the same size allowed this unwanted fragmentation pathway to be avoided, hence greatly simplifying the MS/MS reading step for such undecyl-based poly(triazole amide)s. In poly(alkoxyamine phosphodiester)s, a single dissociation pathway was achieved with repeating units containing an alkoxyamine linkage, which, by very low dissociation energy, made any other chemical bonds MS/MS-silent. Structure of these polymers was further tailored to enhance the stability of those precursor ions with a negatively charged phosphate group per monomer in order to improve their MS/MS readability. Increasing the size of both the alkyl coding moiety and the nitroxide spacer allowed sufficient distance between phosphate groups for all of them to be deprotonated simultaneously. Because the charge state of product ions increased with their polymerization degree, MS/MS spectra typically exhibited groups of fragments at one or the other side of the precursor ion depending on the original alpha or omega end-group they contain, allowing sequence reconstruction in a straightforward manner.
    Mots-clés : Coded monomer sequence, collision-induced dissociation, containing macromolecules, copolymers, fragmentation, information-containing macromolecules, kinetic-energy spectrometry, ms/ms, nomenclature, phosphoramidite, poly(alkoxyamine amide)s, Polymer sequencing, sequence-controlled polymers, tandem mass-spectrometry, time-of-flight.

  • Chaudhari, S. R.; Wisser, D.; Pinon, A. C.; Berruyer, P.; Gajan, D.; Tordo, P.; Ouari, O.; Reiter, C.; Engelke, F.; Coperet, C.; Lelli, M.; Lesage, A.; Emsley, L. Journal of the American Chemical Society 2017, 139 (31), 10609–10612.
    Résumé : Dynamic nuclear polarization (DNP) has recently emerged as a tool to enhance the sensitivity of solid-state NMR experiments. However, so far high enhancements (\textgreater100) are limited to relatively low magnetic fields, and DNP at fields higher than 9.4 T significantly drops in efficiency. Here we report solid-state Overhauser effect DNP enhancements of over 100 at 18.8 T. This is achieved through the unexpected discovery that enhancements increase rapidly with increasing magic angle spinning (MAS) rates. The measurements are made using 1,3-bisdiphenylene-2-phenylallyl dissolved in o-terphenyl at 40 kHz MAS. We introduce a source sink diffusion model for polarization transfer which is capable of explaining the experimental observations. The advantage of this approach is demonstrated on mesoporous alumina with the acquisition of well-resolved DNP surface enhanced Al-27 cross-polarization spectra.
    Mots-clés : enhanced nmr-spectroscopy, high-frequency, mas-dnp, polarizing agents, rotating solids, sensitivity, sites, solid-state nmr, surface, temperature.

  • Climent, C.; Barbatti, M.; Wolf, M. O.; Bardeen, C. J.; Casanova, D. Chemical Science 2017, 8 (7), 4941–4950.
    Résumé : In this study we investigate in detail the photophysics of naphthalene dimers covalently linked by a sulfur atom. We explore and rationalize how the oxidation state of the sulfur-bridging atom directly influences the photoluminescence of the dimer by enhancing or depriving its radiative and non-radiative relaxation pathways. In particular, we discuss how oxidation controls the amount of electronic transfer between the naphthalene moieties and the participation of the SOn bridge in the low-lying electronic transitions. We identify the sulfur electron lone-pairs as crucial actors in the non-radiative decay of the excited sulfide and sulfoxide dimers, which are predicted to proceed via a conical intersection (CI). Concretely, two types of CI have been identified for these dimers, which are associated with the photo-induced pyramidal inversion and reverse fragmentation mechanisms found in aryl sulfoxide dimers. The obtained results and conclusions are general enough to be extrapolated to other sulfur-bridged conjugated dimers, therefore proportionating novel strategies in the design of strongly photoluminescent organic molecules with controlled charge transfer.
    Mots-clés : aryl sulfoxides, basis-set, charge-transfer, density-functional theory, elements, states, systems.

  • Colombani, J.; Chauvet, E.; Amat, S.; Dupuy, N.; Gigmes, D. Analytica Chimica Acta 2017, 960, 53–62.
    Résumé : The effects of radiation on polymeric materials are a topic of concern in a wide range of industries including the sterilization, and the nuclear power industry. While much work has concentrated on systems like polyolefins that are radiation sterilized, some work has been done on epoxy systems. The epoxy system studied is an epoxy/amine paint which is representative of the paint that covers the inner surfaces of the French nuclear reactor containment buildings. In case of a severe accident on a Nuclear Power Plant, fission products can be released from the nuclear fuel to the reactor containment building. Among them, volatile iodine (12) can be produced and can interact with the epoxy-paint. This paint is also subjected to gamma radiation damages (due to the high dose in the containment coming from radio-nuclides released from the fuel). So the epoxy-paint studied was exposed to gamma radiation under air atmosphere after being loaded with I-2 or not. The aim of this study is to characterize by FTIR spectroscopy the iodine-paint interactions, then to identify the radiation damages on the epoxy-paint, and to check their effects on these iodine-paint interactions. This work shows the potential of multi-block analysis method (ANOVA-PCA and COMDIM = AComDim) for such a study as it allows to identify the nature of iodine/epoxy-paint interactions and to characterize the gamma radiation damages on the epoxy-paint. AComDim method conduces to the extraction of Common Components to different tables and highlights factors of influence and their interactions. (C) 2017 Elsevier B.V. All rights reserved.
    Mots-clés : AComDim, anova-pca, charge-transfer complexes, degradation, epoxy coatings, Epoxy-paint, Gamma radiation, Iodine, MIR spectroscopy, molecular-iodine, phebus fp tests, phenoxy resins, radio-oxidation, severe accident simulation, short wavelengths.

  • Curti, C.; Lamy, E.; Primas, N.; Fersing, C.; Jean, C.; Bertault-Peres, P.; Vanelle, P. Pharmazie 2017, 72 (12), 741–746.
    Résumé : Several ocular infections require anti-infectious eye drops prepared by hospital pharmacy. Stability of these preparations is described in the literature, but studies do not always adequately consider physico-chemical parameters or storage conditions. We describe herein a complete study conducted on five anti-infectious eye drops containing vancomycin, gentamicin, ceftazidime, amphotericin B and voriconazole. We looked for significant changes in active pharmaceutical ingredient content, pH, osmolality and subvisible particles. Our study was designed to monitor stability at ambient temperature, at 2-8 degrees C, and also at 2-8 degrees C after various freezing periods. Under ambient storage conditions, eye drops were stable for 15 days, except for ceftazidime, which was stable for less than 1 day only. Under refrigeration conditions (2-8 degrees C), amphotericin B and voriconazole were stable for 60 days, vancomycin and gentamicin were stable for 30 days while ceftazidime was only stable for 15 days. After 90 days freezing and thawing, voriconazole remained stable at 2-8 degrees C for 60 days, vancomycin and amphotericin B for 30 days and gentamicin only for 21 days. Ceftazidime eye drops were stable for only 7 days at 2-8 degrees C after 60 days freezing. Our results are compared to the most relevant publications. Results of this study allow the compounding of large batches of harmonized anti-infectious eye drops.
    Mots-clés : 1-percent, antibiotics, ceftazidime, derivatization, formulation, keratitis, liquid-chromatographic method, phenylisocyanate, vancomycin, voriconazole ophthalmic solution.

  • Da Costa, L.; Scheers, E.; Coluccia, A.; Rosetti, A.; Roche, M.; Neyts, J.; Terme, T.; Cirilli, R.; Mirabelli, C.; Silvestri, R.; Vanelle, P. European Journal of Medicinal Chemistry 2017, 140, 528–541.
    Résumé : Rhinovirus (RV), member of the Enterovirus genus, is known to be involved in more than half of the common colds. Through advances in molecular biology, rhinoviruses have also been associated with exacerbations of chronic pulmonary diseases (e.g. asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis). In the current investigation, we develop a novel series of 4,5-dimethoxybenzyl derivatives that potently inhibits rhinovirus replication. Compound (S)-7f blocks RV-B14 replication with an EC50 value of 0.25 mu M and shows a low toxicity in HeLa cells (CC50 \textgreater 271 mu M). Enantioseparation followed by an absolute configuration determination by a Mosher's method revealed the interest of enantiopure compounds. Molecular docking studies permitted the identification of key biological interactions within the drug-binding pocket and an in silico drug-like study revealed a good potential for the development of these derivatives. (C) 2017 Elsevier Masson SAS. All rights reserved.
    Mots-clés : 14 infection, absolute-configuration, Capsid-binder, common cold, compound, dynamics, Enantioseparation, entry, Heterocycles, inhibitors, Mosher's method, replication, rv-b14, virus, VP1 protein.

  • Dagousset, G.; Simon, C.; Anselmi, E.; Tuccio, B.; Billard, T.; Magnier, E. Chemistry-a European Journal 2017, 23 (18), 4282–4286.
    Résumé : We report the first use of N-trifluoromethylthiosaccharin as the source of SCF3 radical under photoredox catalysis. This allowed an efficient and general visiblelight-mediated carbotrifluoromethylthiolation of alkenes. Under the optimized conditions using fac-[Ir(ppy)(3)] as the photocatalyst, various N-aryl acrylamides as well as a wide range of substituted styrenes can readily be difunctional-ized in an intra- or intermolecular fashion, affording the corresponding SCF3-containing products in good to excellent yield. Importantly, the formation of this SCF3 radical along with other key radical intermediates was unambiguously demonstrated thanks to spin trapping/electron paramagnetic resonance (ST/EPR) experiments, which enabled a clear understanding of the reaction mechanism.
    Mots-clés : activated alkenes, bonds, carbotrifluoromethylthiolation, carboxylic-acids, chloride, cyclization, electrophilic trifluoromethanesulfanylation, EPR spectroscopy, fluorine, mediated oxidative trifluoromethylthiolation, photoredox catalysis, radicals, reagent, trifluoromethylthiosaccharin, visible-light.

  • David, G.; Guillery, N.; Ferre, N. Journal of Chemical Theory and Computation 2017, 13 (12), 6253–6265.
    Résumé : Analytical expressions of the interactions present in the Heisenberg-Dirac van Vleck and Hubbard Hamiltonians have been derived as functions of both the energy of several broken symmetry DFT solutions and their expectation value of the S-2 spin operator. Then, following a strategy of decomposition of the magnetic exchange coupling into its main contributions (direct exchange, kinetic exchange, and spin polarization) and using a recently proposed method of spin decontamination, values of these interactions have been extracted. As already observed, they weakly depend on the correlation functional but strongly depend on the exchange one. In order to distinguish between the effect of the delocalization of the magnetic orbitals and that of the amount of Hartree-Fock exchange (HFX) when hybrid exchange-correlation functionals are used, we have disentangled these two contributions by either freezing the magnetic orbitals and varying the amount of HFX or varying the magnetic orbitals while keeping the same amount of HFX. As expected, increasing the amount of HFX induces a slight relocalization of the magnetic orbitals on the magnetic center which results in a weak increase of the repulsion energy U parameter and a weak decrease of both the direct exchange K-ab and hopping vertical bar t vertical bar parameters. Conversely, the amount of HFX has a huge effect on all the parameters, even when some of the parameters should be exchange-independent, like U. Indeed, it is analytically demonstrated that the physical content of the U parameter extracted from several broken-symmetry solutions depends on the amount of HFX and that this pathological behavior has the same origin as the self-interaction error. This result is interesting not only to theoretical chemists working in the field of magnetic systems but also to DFT methodologists interested in using this theory for studying either excited states or strongly correlated systems. Finally, the performance of the range-separated omega B97XD functional for both ferromagnetic and antiferromagnetic transition-metal compounds and organic systems must be noted.
    Mots-clés : binuclear complexes, computations, density-functional-theory, energy differences, exchange interactions, p-benzyne, performance, proper use, spin states, transition-metal chemistry.

  • Desroches, J.; Kieffer, C.; Primas, N.; Hutter, S.; Gellis, A.; El-Kashef, H.; Rathelot, P.; Verhaeghe, P.; Azas, N.; Vanelle, P. European Journal of Medicinal Chemistry 2017, 125, 68–86.
    Résumé : From 4 antiplasmodial hit-molecules identified in 2-trichloromethylquinazoline series, we conducted a global Structure-Activity relationship (SAR) study involving 26 compounds and covering 5 molecular regions (I - V), aiming at defining the corresponding pharmacophore and identifying new bioactive derivatives. Thus, after studying the aniline moiety in detail, thienopyrimidine, quinoline and quinoxaline bio-isosters were synthesized and tested on the K1 multi-resistant P. falciparum strain, along with a cytotoxicity evaluation on the human HepG2 cell line, to define selectivity indecies. SARs first showed that thienopyrimidines and quinolines were globally more cytotoxic, while quinoxaline analogs appeared as active as- and less cytotoxic than their quinazoline counterparts. Such pharmacomodulation in quinoxaline series not only provided a new antiplasmodial reference hit-molecule (IC50 = 0.4 mu M, selectivity index = 100), but also highlighted an active (IC50 = 0.4 mu M) and quite selective (SI = 265) synthesis intermediate. (C) 2016 Elsevier Masson SAS. All rights reserved.
    Mots-clés : acidic conditions, agents, antimalarial compounds, condensed 4-chloropyrimidines, Heterocycles, In vitro antiplasmodial activity, In vitro HepG2 cytotoxicity, in-vitro evaluation, methyltransferase inhibitors, nitriles, Plasmodium falciparum, Quinazoline, quinazoline derivatives, Quinoline, Quinoxaline, series, Structure-activity relationships, Thienopyrimidine, Trichloromethyl goup.

  • Djeridi, W.; Ben Mansour, N.; Ouederni, A.; Llewellyn, P. L.; El Mir, L. International Journal of Hydrogen Energy 2017, 42 (13), 8905–8913.
    Résumé : Nanoporous carbons were synthesized at certain conditions by sol gel method combined with furnace firing in inert atmosphere from pyrogallol-formaldehyde (PF) mixtures in water using perchloric acid as catalyst. Their morphology was studied experimentally to examine their adsorption capacity for greenhouse gases. The preparation conditions of the nanoporous carbons were explored by changing the pyrolysis temperature. The effect of this factor on determining the pore structures and the adsorption capacities were evaluated. The synthesized xerogels were characterized by X-ray diffraction, nitrogen adsorption desorption isotherms, thermogravimetric analysis (TGA), differential thermal analysis (DTA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that surface areas and nitrogen adsorption capacity are dependent completely on the pyrolysis temperature. Equilibrium and enthalpies studies for the CO2 and CH4 adsorption on PF were measured at room temperature and up to 25 bar. The adsorption capacity on PF was highest for CO2 and then CH4. The best sample shows maximal adsorption capacities as follows 5.50 mmol g(-1) of CH4 and 7.62 mmol g(-1) of CO2 at 25 bar and 30 degrees C. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
    Mots-clés : activated carbon, co2 adsorption, Dioxide carbon adsorption, Enthalpies, hydrogen adsorption, metal-organic frameworks, Methane adsorption, Nanoporous carbon, natural-gas storage, plant flue-gas, polymers, pressure swing adsorption, Sol-gel method, texture, xerogels.

  • Dol, C.; Vibert, F.; Bertrand, M. P.; Lalevee, J.; Gastaldi, S.; Besson, E. Acs Macro Letters 2017, 6 (2), 117–120.
    Résumé : New polysilsesquioxane-based lamellar materials, functionalized with radical precursors, were synthesized. They play a double role in the preparation of composite materials: first, as filler homogeneously dispersed in the monomer after delamination, second as radical initiator in photopolymerization. These polysilsesquioxanes enable fast and efficient photopolymerization upon UV light for thick samples. High conversions in monomers as well as the formation of hybrid polymers covalently linked to the filler are observed. This strategy, based on a double bottom-up approach, avoids the solubility/dispersion problem encountered in the classical preparation of composite polymers from preformed organic polymers.
    Mots-clés : nanocomposites, resonance, silica, spin, sulfur.

  • Durand, G.; Rosselin, M.; Klein, P. - A.; Zeamari, K.; Choteau, F.; Tuccio, B. Journal of Organic Chemistry 2017, 82 (1), 135–142.
    Résumé : Two bifunctional alpha-phenyl-N-cyclohexyl nitrones were synthesized with the expectation that the cyclohexyl ring will impart lipophilicity to the molecule, high reactivity to the nitronyl group, and stability to the spin adducts formed. The synthesis Of the acid nitrone 4 and its corresponding tent-butyl ester 3 was initiated by a Michael reaction to introduce the cyclohexyl ring. A Zn/AcOH-mediated reduction of the nitro functionality followed by, condensation onto benzaldehyde generated the nitronyl function. In agreement with their high lipophilicity values, nitrone was insoluble in water, while nitrone 4 exhibited a poor water solubility. It was determined that the presence of the cyclohexyl ring did not affect either the reduction or oxidation potentials of the nitronyl group in comparison to the classical alpha-phenyl-N-tert-butylhitrone (PBN). The spin trapping ability of 3 and 4 was investigated by EPR for oxygen- and carbon-centered radicals. In most cases, the nitrones gave rise to a standard six-line EPR spectrum whose values were in agreement with the literature, accompanied by a minor second species. In DMSO, the half-lives of nitrone 3 and 4-OOH adducts were double that of PBN, suggesting that the Stabilization comes from, the cyclohexyl ring and/or the electronic effect of the carboxylic acid.
    Mots-clés : agents, cyclic nitrones, derivatives, in-vitro, oxide, reactivity, superoxide radical-anion, tert-butyl nitrones, therapeutics, trapping properties.

  • Fazzi, D.; Barbatti, M.; Thiel, W. Journal of Physical Chemistry Letters 2017, 8 (19), 4727–4734.
    Résumé : The evolution of the excited-state manifold in organic D/A aggregates (e.g., the prototypical P3HT/PCBM) is investigated through a bottom-up approach via first-principles calculations. We show how the excited-state energies, the charge transfer (CT) states, and the electron hole density distributions are strongly influenced by the size, the orientation, and the position (i.e., on-top versus on-edge phases) of P3HT/PCBM domains. We discuss how the structural order influences the excited-state electronic structure, providing an atomistic interpretation of the photophysics of organic blends. We show how the simultaneous presence of on-top and on-edge phases does not alter the optical absorption spectrum of the blend but does affect the photophysics. Photovoltaic processes such as (i) the simultaneous charge generation obtained from hot and cold excitations, (ii) the instantaneous and delayed charge separation, and (iii) the pump-push-probe charge generation can be interpreted based on our study.
    Mots-clés : delocalization, dissociation, environment, excitations, greens-functions theory, heterojunctions, nonadiabatic dynamics, semiconductors, separated hybrid functionals, solar-cells.

  • Gao, X.; Bai, S.; Fazzi, D.; Niehaus, T.; Barbatti, M.; Thiel, W. Journal of Chemical Theory and Computation 2017, 13 (2), 515–524.
    Résumé : A new versatile code based on Python scripts was developed to calculate spin-orbit coupling (SOC) elements between singlet and triplet states. The code, named PySOC, is interfaced to third party quantum chemistry packages, such as Gaussian 09 and DFTB+. SOCs are evaluated using linear-response (LR) methods based on time dependent density functional theory (TDDFT), the Tamm-Dancoff approximation (TDA), and time-dependent density functional tight binding (TD-DFTB). The evaluation employs Casida-type wave functions and the Breit-Pauli (BP) spin-orbit Hamiltonian with an effective charge approximation. For validation purposes, SOCs calculated with PySOC are benchmarked for several organic molecules, with SOC values spanning several orders of magnitude. The computed SOCs show little variation with the basis set, but are sensitive to the chosen density functional. The benchmark results are in good agreement with reference data obtained using higher-level spin-orbit Hamiltonians and electronic structure methods, such as CASPT2 and DFT/MRCI. PySOC can be easily interfaced to other third-party codes and other methods yielding CI-type wave functions.
    Mots-clés : complex materials, conical intersections, effective nuclear charges, excitation-energies, gaussian-basis sets, generalized-gradient-approximation, light-emitting-diodes, nonadiabatic molecular-dynamics, order regular approximation, tamm-dancoff approximation.

  • Garra, P.; Dumur, F.; Al Mousawi, A.; Graff, B.; Gigmes, D.; Morlet-Savary, F.; Dietlin, C.; Fouassier, J. P.; Lalevee, J. Polymer Chemistry 2017, 8 (38), 5884–5896.
    Résumé : Significant improvements of the recently proposed Cu(I)/vitamin C + water/dibenzoyl peroxide (BPO) system for the redox free radical polymerization of methacrylates in air are presented here, the goal being to avoid the presence of water and to eliminate the unstable BPO compound. Additionally, the use of mechanosynthesized Cu(I) complexes bearing cheap triphenylphosphine and methylpyridine ligands, allowed us to reduce the economical and synthesis costs significantly. Water-free reducing agents such as 6-O-palmitoyl-L-ascorbic acid, organotin or hydrazine derivatives are evaluated. Cumene hydroperoxide and tert-butyl perbenzoate are proposed as a replacement for less stable BPO. Most of these novel combinations are more efficient in air than the usual amine/benzoylperoxide system (4-N, N-TMA/BPO) reference especially at the sample surface. Among them, Cu(I)/organotin/cumene hydroperoxide appears as an efficient and competitive alternative to the conventional amine/BPO couple.
    Mots-clés : confocal raman microscopy, cure, decomposition, dental resins, free-radical polymerization, mechanochemistry, methyl-methacrylate, oxygen inhibition, peroxide, photopolymerization.

  • Garra, P.; Dumur, F.; Gigmes, D.; Al Mousawi, A.; Morlet-Savary, F.; Dietlin, C.; Fouassier, J. P.; Lalevee, J. Macromolecules 2017, 50 (10), 3762–3772.
    Résumé : The free radical polymerization of low viscosity methacrylate blends upon a LED irradiation at 405 nm under air is carried out using Cu(I)/iodonium salt/tin(II) organic derivative as photoinitiating systems. The system exhibits a high reactivity; where tin derivative plays a crucial role. It operates through a catalytic cycle in which Cu(I) is regenerated and can be used at low concentrations (0.1-0.3 wt %). Remarkable performances are achieved. At first, a final methacrylate conversion of 82% after 40 s in 1.4 mm thick samples is obtained for an irradiance of 35 mW/cm(2) whereas such a conversion is only reached only when using Cu(I)/iodonium salt system under a 200 mW/cm(2) light exposure. Second, a 55% conversion is still obtained after 150 s under a very low irradiance (2.5 mW/cm(2)). Third, almost tack-free thick samples (1.4 mm) under air are produced upon sunlight exposure (65% of conversion for the 1.4 mm thick sample after 90 s of irradiation). Fourth, the photocuring of clear samples as thick as 9 cm (and presumably even more) with an impressive homogeneity through the entire polymerizable medium is feasible; the photopolymerization of 8.5 cm thick filled samples is also realized. Fifth and last, a lateral polymerization beyond the irradiated area is demonstrated with unprecedented extensions of 8 mm (tin(II) = 1.3%) and 28 mm (tin(II) = 8%), which allows polymerization reactions to occur in shadowed areas. The Chemical mechanisms are studied by steady state photolysis and ESR-spin trapping experiments. The subsequent role of the hydroperoxides (ROOH) formed during the polymerization reaction is a key point i.e. for the polymerization in shadowed areas (thick and filled samples), these latent species (ROOH) will be generated from the oxygen inhibition and can diffuse for a full curing of the samples through a ROOH/Cu(I) redox initiation.
    Mots-clés : atrp, chemistry, green, initiation, methyl-methacrylate, peroxide, photoinitiating systems, Polymerization, resins, visible-light.

  • Garra, P.; Dumur, F.; Morlet-Savary, F.; Dietlin, C.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Journal of Polymer Science Part a-Polymer Chemistry 2017, 55 (21), 3646–3655.
    Résumé : The first use of a new mechanosynthesized copper complex (Cu(acac)(2dppba)) as a initiator for the redox and redox photoactivated polymerization of methacrylates under air is proposed. This paper (i) describes the mechanosynthesis of this complex, (ii) outlines the relative efficiency of the complex for redox polymerization (mechanosynthesized product vs. solvent synthesized product), (iii) follows the polymerization enhancement under a 405 nm light, and (iv) demonstrates the high performance of this complex in near infrared photoactivated redox polymerization where a completely colorless polymer is obtained (unprecedented under NIR irradiations, 785 nm, here). The light activated polymerization exhibit higher conversions, better time controls (activation control) and higher surface conversions than redox polymerization. The mechanosynthesis is well characterized by two solvent-free methods (visual color change and Electron Spin Resonance) and two solvent-based methods (high resolution-electrospray ionization-mass spectrometry (HR-ESI-MS) and UV-vis spectrometry). The involved mechanisms are discussed. Mechanosynthesis of copper complexes opens new perspectives for copper (photo)redox polymerization catalysts as the environmental impact and economical costs of the complex synthesis are significantly reduced. (c) 2017 Wiley Periodicals, Inc.
    Mots-clés : (photo)initiators, (photo)redox catalysis, confocal raman microscopy, epr, ligands, mechanochemical synthesis, mechanosynthesis, methyl-methacrylate, nir, photosensitizers, Polymerization, resins, x-ray.

  • Garra, P.; Kermagoret, A.; Al Mousawi, A.; Dumur, F.; Gigmes, D.; Morlet-Savary, F.; Dietlin, C.; Fouassier, J. P.; Lalevee, J. Polymer Chemistry 2017, 8 (28), 4088–4097.
    Résumé : Novel copper complex based initiating systems for redox free radical polymerization (FRP) of methacrylate resins under mild conditions are proposed. Remarkably, the FRP performance of the Cu(I)/ascorbic acid (Vitamin C - VitC)/benzoyl peroxide (BPO) redox system is noticeably more significant than that of the amine/BPO reference especially at the top surface where the oxygen inhibition is particularly deleterious. The Cu(I)/BPO interaction leads to a decomposition of the peroxide and generates a benzoyl radical and Cu(II) as a byproduct. The ascorbic acid acts as a reducing agent and allows the regeneration of Cu(I) from Cu(II). Hydroperoxides formed at the surface through the radical/O-2 interaction are also decomposed by the new proposed Cu complex leading to additional polymerization initiating species. The structure/ reactivity relationship of the new proposed Cu(I) complexes in the Cu(I)/VitC/BPO systems is studied. The use of Cu(I)/VitC/BPO/iodonium salt systems in redox photoactivated FRP is also explored.
    Mots-clés : amine, bone cements, confocal raman microscopy, cure, decomposition, dental resins, free-radical polymerization, methyl-methacrylate, oxygen inhibition, reactivity.

  • Garra, P.; Dietlin, C.; Morlet-Savary, F.; Dumur, F.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Polymer Chemistry 2017, 8 (46), 7088–7101.
    Résumé : The photopolymerization processes are currently associated with thin samples for which the light penetration is good enough to activate the photoinitiator or the photoinitiating system for the entre sample's thickness. The photopolymerization of very thick films and in shadow areas where the light penetration is inhibited (e.g. in filled, pigmented, and dispersed samples) remains a huge challenge (e.g. for the access to composites). In the present paper, an overview of the different strategies for the photopolymerization of thick samples is reported. First, strategies based on the optimization of the photonic (light intensity, excitation wavelength, etc.) or chemical (efficiency/reactivity/bleaching of the photoinitiating systems, etc.) parameters are presented that result in a full temporal and spatial control. Then, the main strategies based on propagation/diffusion mechanisms of latent species for the curing beyond the irradiated areas are given (partial loss of spatial resolution and access to shadow areas). Also, dual systems (thermal/ photochemical or photochemical/redox) are described. The state of the art for the access to thick samples by photopolymerization processes as well as some perspectives are provided.
    Mots-clés : 3d printing resins, active-center lifetime, electron-paramagnetic-resonance, free-radical photopolymerization, frontal polymerization, phototriggered base proliferation, redox initiating systems, translucent fiberglass post, up-conversion particles, visible-light.

  • Gaston, F.; Dupuy, N.; Marque, S. R. A.; Barbaroux, M.; Dorey, S. Analytica Chimica Acta 2017, 981, 11–23.
    Résumé : To highlight the main factors involved in the degradation of polymers in multilayer films under girradiation, the ANOVA Common Dimensions (AComDim, Analysis of Variance in Common Dimensions) method is applied on spectra recorded with ATR-FTIR (Attenuated Total Reflection- Fourier Transform Infrared). The present study focuses on the stability of gamma-irradiated polymers used in single-use plastic bags made of multilayer films for the biopharmaceutical and biotechnological industries. The samples are irradiated at several gamma-doses, up to 270 kGy, and compared with a non-irradiated sample used as reference. It shows that the gamma-dose, the natural ageing up to six months and the gamma-dose x ageing interaction are the most influential factors. (C) 2017 Elsevier B.V. All rights reserved.
    Mots-clés : AComDim, common components, degradation, dose-rate, electron-beam, Ethylene vinyl acetate, ethylene-butene, experimental-design, FTIR spectra, gamma-irradiation, low-density polyethylene, oxidation, Polyethylene, radiation, weights analysis.

  • Giner, E.; Tenti, L.; Angeli, C.; Ferre, N. Journal of Chemical Theory and Computation 2017, 13 (2), 475–487.
    Résumé : The present paper reports an original computational strategy for the computation of the isotropic hyperfine coupling constants (hcc). The algorithm proposed here is based on an approach recently introduced by some of the authors, namely, the first-order breathing orbital self-consistent field (FOBO-SCF). The approach is an almost parameter-free wave function method capable to accurately treat the spin delocalization together with the spin polarization effects while staying in a restricted formalism and avoiding spin contamination. The efficiency of the method is tested on a series of small radicals, among which four nitroxide radicals and the comparison with high-level ab initio methods show very encouraging results. On the basis of these results, the method is then applied to compute the hcc of a challenging system, namely, the DEPMPO-OOH radical in various conformations. The reference values obtained on such a large system allows us to validate a cheap computational method based on density functional theory (DFT). Another interesting feature of the model applied here is that it allows for the rationalization of the results according to a relatively simple scheme based on a two-step mechanism. More precisely, the results are analyzed in terms of two separated contributions: first the spin delocalization and then the spin polarization.
    Mots-clés : accurate, binuclear complexes, cluster, free-radicals, gaussian-basis sets, magnetic-interactions, model, perturbation-theory, spin polarization, systems.

  • Gmeiner, C.; Klose, D.; Mileo, E.; Belle, V.; Marque, S. R. A.; Dorn, G.; Allain, F. H. T.; Guigliarelli, B.; Jeschke, G.; Yulikov, M. Journal of Physical Chemistry Letters 2017, 8 (19), 4852–4857.
    Résumé : Site-directed spin labeling of native tyrosine residues in isolated domains of the protein PTBP1, using a Mannich-type reaction, was combined with conventional spin labeling of cysteine residues. Double electron electron resonance (DEER) EPR measurements were performed for both the nitroxide nitroxide and Gd(III) nitroxide label combinations within the same protein molecule. For the prediction of distance distributions from a structure model, rotamer libraries were generated for the two linker forms of the tyrosine-reactive isoindoline-based nitroxide radical Nox. Only moderate differences exist between the spatial spin distributions for the two linker forms of Nox. This strongly simplifies DEER data analysis, in particular, if only mean distances need to be predicted.
    Mots-clés : aspartate transporter, biomacromolecules, deer, distance measurements, electron-paramagnetic-resonance, membrane, nitroxide, nucleic-acids, peldor, rna.

  • Ho, H. T.; Tintaru, A.; Rollet, M.; Gigmes, D.; Phan, T. N. T. Polymer Chemistry 2017, 8 (37), 5660–5665.
    Résumé : In this Communication, we report the synthesis of a series of potassium sulfonyl (trifluoromethanesulfonyl) imide (STFSI) derivatives, bearing at one extremity the STFSI group and at the other extremity either bromo, azido or amine groups. The resultant STFSI derivatives were subsequently used in the post-polymerization functionalization of (co)polymers to yield functionalized (co)polymers by exploiting the highly efficient coupling reactions, namely alkylation, amidation and alkyne-azide cycloaddition.
    Mots-clés : block-copolymers, click chemistry, electrolytes, lithium batteries, membrane, methacrylate, poly(ionic liquid)s, polymers, radical polymerization, triblock copolymers.
  • Ibrahim-Ouali, M.; Dumur, F. Arkivoc 2017, 202–256.
    Résumé : We review the most important achievements of the last decade in the field of steroid synthesis in the presence of copper catalysts. This method shows great promise to allow the development of novel molecules with different functions using copper as catalyst.
    Mots-clés : 1, 2, 3-triazole ring, alkynylsteroids, azide-alkyne cycloaddition, azidosteroids, bile-acid dimers, carbon-monoxide, click chemistry, Copper catalysed reactions, cycloaddition, derivatives, efficient synthesis, in-vitro, ligands, receptors, triazoles.

  • Jankowska, J.; Barbatti, M.; Sadlej, J.; Sobolewski, A. L. Physical Chemistry Chemical Physics 2017, 19 (7), 5318–5325.
    Résumé : Small molecular systems exhibiting Excited State Intramolecular Proton Transfer (ESIPT) attract considerable attention due to their possible role as ultrafast, efficient, and photostable molecular photoswitches. Here, by means of static potential energy profile scan and on-the-fly non-adiabatic dynamics simulations we study the photodeactivation process of a minimal-chromophore aromatic Schiff base, salicylidene methylamine (SMA), and its two derivatives 6-cyano-salicylidene methylamine (6-CN-SMA) and 3-hydroxy-salicylidene methylamine (3-OH-SMA). We show that the dominant character of the lowest excited singlet state -pi pi* vs. n pi* -plays a crucial role in the system's photophysics and controls the ESIPT efficiency. We also show that the relative alignment of the pi pi* and n pi* states may be controlled through chemical substitutions made to the aromatic ring of the Schiff-base molecule. We believe that our findings will improve the rational-design strategies employed for the ESIPT systems, especially in the context of their possible photoswitching.
    Mots-clés : chromophore, density, DNA, electronic-structure, fluorescent protein, hydrogen-atom transfer, photochromism, photodynamics, salicylidene methylamine, switch driven.

  • Jimenez-Sanchez, G.; Terrat, C.; Verrier, B.; Gigmes, D.; Trimaille, T. Chemical Communications 2017, 53 (57), 8062–8065.
    Résumé : An antigen probe (HIV-1 p24) immobilized onto N-succinimidyl ester based micelles was used as a solid phase coating in ELISA test, and induced a significant improvement in antibody detection sensitivity as compared to the standard free antigen coating. The relevance of this straightforward approach to improve the bioassay sensitivity was confirmed by using biotin as a generic probe.
    Mots-clés : antibodies, copolymer, diagnostics, increases, polymer.

  • Kalashnyk, N.; Mouhat, K.; Oh, J.; Jung, J.; Xie, Y.; Salomon, E.; Angot, T.; Dumur, F.; Gigmes, D.; Clair, S. Nature Communications 2017, 8, 14735.
    Résumé : In the blooming field of on-surface synthesis, molecular building blocks are designed to self-assemble and covalently couple directly on a well-defined surface, thus allowing the exploration of unusual reaction pathways and the production of specific compounds in mild conditions. Here we report on the creation of functionalized organic nanoribbons on the Ag(110) surface. C-H bond activation and homo-coupling of the precursors is achieved upon thermal activation. The anisotropic substrate acts as an efficient template fostering the alignment of the nanoribbons, up to the full monolayer regime. The length of the nanoribbons can be sequentially increased by controlling the annealing temperature, from dimers to a maximum length of about 10 nm, limited by epitaxial stress. The different structures are characterized by room-temperature scanning tunnelling microscopy. Distinct signatures of the covalent coupling are measured with high-resolution electron energy loss spectroscopy, as supported by density functional theory calculations.
    Mots-clés : covalent nanostructures, graphene nanoribbons, hydrogen, metal-surfaces, phthalocyanine, Polymerization, polymers, reactivity, terminal alkynes, wires.

  • Kalyanaraman, B.; Cheng, G.; Hardy, M.; Ouari, O.; Sikora, A.; Zielonka, J.; Dwinell, M. Interface Focus 2017, 7 (2), 20160109.
    Résumé : Reports suggest that metformin exerts anti-cancer effects in diabetic individuals with pancreatic cancer. Thus, metformin is currently being repurposed as a potential drug in cancer treatment. Studies indicate that potent metformin analogues are required in cancer treatment because of the low bioavailability of metformin in humans at conventional antidiabetic doses. We proposed that improved mitochondrial targeting of metformin by attaching a positively charged lipophilic triphenylphosphonium group will result in a new class of mitochondria-targeted metformin analogues with significantly enhanced anti-tumour potential. Using this approach, we synthesized various mitochondria-targeted metformin analogues with different alkyl chain lengths. Results indicate that the antiproliferative effects increased with increasing alkyl chain lengths (100-fold to 1000-fold). The lead compound, mito-metformin(10), potently inhibited mitochondrial respiration through inhibition of complex I, stimulation of superoxide and hydrogen peroxide formation and activation of AMPK. When used in combination with ionizing radiation, mito-metformin(10) acted as a radiosensitizer of pancreatic cancer cells. Because of the 1000-fold-higher potency of mitochondria-targeted metformin(10), therapeutically effective plasma concentrations likely can be achieved in cancer patients.
    Mots-clés : ampk, analogs, anti-cancer agent, biguanides, bioenergetics, cancer-cell sensitivity, drugs, endothelium, generation, metabolism, metformin, mitochondria, peroxynitrite, radiosensitization, Reactive oxygen species, redox signalling.

  • Kalyanaraman, B.; Cheng, G.; Hardy, M.; Ouari, O.; Sikora, A.; Zielonka, J.; Dwinell, M. B. Cell Biochemistry and Biophysics 2017, 75 (3-4), 311–317.
    Résumé : Metformin, one of the most widely prescribed antidiabetic drugs in the world, is being repurposed as a potential drug in cancer treatment. Epidemiological studies suggest that metformin exerts anticancer effects in diabetic patients with pancreatic cancer. However, at typical antidiabetic doses the bioavailability of metformin is presumably too low to exert antitumor effects. Thus, more potent analogs of metformin are needed in order to increase its anticancer efficacy. To this end, a new class of mitochondria-targeted metformin analogs (or mito-metformins) containing a positively-charged lipophilic triphenylphosphonium group was synthesized and tested for their antitumor efficacy in pancreatic cancer cells. Results indicate that the lead compound, mito-metformin(10), was nearly 1000-fold more potent than metformin in inhibiting mitochondrial complex I activity, inducing reactive oxygen species (superoxide and hydrogen peroxide) that stimulate redox signaling mechanisms, including the activation of adenosinemonophosphate kinase and inhibition of proliferation of pancreatic cancer cells. The potential use of the low-temperature electron paramagnetic resonance technique in assessing the role of mitochondrial complexes including complex I in tumor regression in response to metformin and mito-metformins in the in vivo setting is discussed.
    Mots-clés : analogs, biguanides, bioenergetics, cell-death, energy-metabolism, hydroethidine, identification, intracellular superoxide, Mitochondrial metabolism, Modified metformin, Pancreatic cancer, pancreatic-cancer, peroxynitrite, Reactive oxygen species, Redox signaling.

  • Kalyanaraman, B.; Hardy, M.; Podsiadly, R.; Cheng, G.; Zielonka, J. Archives of Biochemistry and Biophysics 2017, 617, 38–47.
    Résumé : In this review, some of the recent developments in probes and assay techniques specific for superoxide (O-2(center dot-)) and hydrogen peroxide (H2O2) are discussed. Over the last decade, significant progress has been made in O-2(center dot-) and H2O2 detection due to syntheses of new redox probes, better understanding of their chemistry, and development of specific and sensitive assays. For superoxide detection, hydroethidine (HE) is the most suitable probe, as the product, 2-hydroxyethidium, is specific for O-2(center dot-). In addition, HE derived dimeric products are specific for one-electron oxidants. As red-fluorescent ethidium is always formed from HE intracellularly, chromatographic techniques are required for detecting 2-hydroxyethidium. HE analogs, Mito-SOX and hydropropidine, exhibit the same reaction chemistry with O-2(center dot-) and one-electron oxidants. Thus, mitochondrial superoxide can be unequivocally detected using HPLC-based methods and not by fluorescence microscopy. Aromatic boronate-based probes react quantitatively with H2O2, forming a phenolic product. However, peroxynitrite and hypochlorite react more rapidly with boronates, forming the same product. Using ROS-specific probes and HPLC assays, it is possible to screen chemical libraries to discover specific inhibitors of NADPH oxidases. We hope that rigorous detection of O-2(center dot-) and H2O2 in different cellular compartments will improve our understanding of their role in redox signaling. (C) 2016 Elsevier Inc. All rights reserved.
    Mots-clés : amplex red, cellular bioenergetics, Fluorescent probes, in-vivo, intracellular superoxide, mediated oxidation, Mitochondrial complex I, myeloperoxidase activity, NADPH oxidase, oxidative stress, Oxy radicals, peroxynitrite formation, reactive oxygen, resorufin implications, Signal transducer.

  • Kandouli, C.; Cassien, M.; Mercier, A.; Delehedde, C.; Ricquebourg, E.; Stocker, P.; Mekaouche, M.; Leulmi, Z.; Mechakra, A.; Thetiot-Laurent, S.; Culcasi, M.; Pietri, S. Journal of Ethnopharmacology 2017, 207, 251–267.
    Résumé : Ethnopharmacological relevance: According to Saharian traditional medicine, Anvillea radiata Coss. & Dur. (Asteraceae) has been valued for treating a variety of ailments such as gastro-intestinal, liver and pulmonary diseases, and has gained awareness for its beneficial effect on postprandial hyperglycemia. However, to best of our knowledge, no detailed study of the antidiabetic curative effects of this plant has been conducted yet. Aim of the study: To determine the hypoglycemic and antidiabetic effect of dietary supplementation with Anvillea radiata extracts on high-fat-diet (HFD)-induced obesity and insulin resistance in C57BL/6 J mice in relation with antioxidant, anti-inflammatory, pancreatic beta-cells and skeletal muscle protection, and digestive enzyme inhibiting properties. Materials and methods: Six extracts (water soluble and organic) from aerial parts of the plant were analyzed phytochemically (total phenolic and flavonoid content) and screened for in vitro superoxide (by chemiluminescence) and hydroxyl radical (by electron paramagnetic resonance spin-trapping) scavenging, antioxidant (DPPH, TRAP and ORAC assays), xanthine oxidase, metal chelating, a-amylase and a-glucosidase inhibitory property, and protective effects on copper-induced lipoprotein oxidation. Then selected hydroalcoholic and aqueous extracts were assessed for toxicity in normal human lung fibroblasts and A549 cancer cells using FMCA and MTT assays. Two water-soluble extracts having the best overall properties were assessed for their (i) protective effect at 1-15 mu g/mL on metabolic activity of rat insulinoma-derived INS-1 cells exposed to hyperglycemic medium, and (ii) acute hypoglycemic effect on 16-weeks HFD-induced diabetic mice. Then diabetic mice were administered HFD supplemented by extracts (up to 150 mg/kg/day) for 12 additional weeks using standard diet as control and the antidiabetic drug, metformin (150 mg/kg), as positive control. Then the antidiabetic, anti-inflammatory and antioxidant activity of extracts were determined. Results: Of the highly efficient polyphenolics-enriched hydroalcoholic and ethyl acetate extracts, the lyophilized aqueous (AQL) and butanol extracts were not toxic in cells (\textless= 400 mu g/mL) or when given orally in normal mice (\textless= 2000 mg/kg), exerted a dose-dependent hypoglycemic action in diabetic mice, which was maximal at the dose of 150 mg/kg. Upon administering this dose for 12 weeks, both extracts significantly ameliorated body weight control capacity, recovery of plasma glucose and insulin level, reduced oxidative stress in blood, myocardial and skeletal muscles, and improved hyperlipidemic and inflammatory status. Moreover, diabetes-related complications were optimally ameliorated by oral therapy based on halved doses (75 mg/kg) of a mixture of AQL and metformin. Conclusions: Current investigation supports the traditional medicinal usage of Anvillea radiata and suggests that both readily accessible and low-cost bio-extracts have the potency to develop an antihyperglycemic, antihyperlipidemic and protective agent against beta-cells and muscle dysfunction at doses compatible with the common practices of indigenous people for the management of metabolic disorders.
    Mots-clés : Anvillea radiata, C57/BL6J mice, constituents, diabetic complications, flavonoids, hydroxyl radicals, in-vitro, mechanisms, Medicinal plants, oxidative stress, pancreatic alpha-amylase, Pancreatic beta-cells, phenolic-compounds, plant-extracts, Total phenolics, Type 2 diabetes.

  • Karamessini, D.; Poyer, S.; Charles, L.; Lutz, J. - F. Macromolecular Rapid Communications 2017, 38 (24), 1700426.
    Résumé : Mixtures of uniform sequence-defined oligourethanes are evaluated as 2D molecular barcodes for labeling three different commodity polymers, namely polystyrene, polyvinylchloride and polyethylene terephthalate. Six different oligourethanes are synthesized by solid-phase iterative synthesis and are coded using a binary monomer alphabet. High-resolution mass spectrometry studies indicate that all oligomers are uniform and sequence-defined. However, instead of using them as individual coded chains, oligomers with different chain-length, mass and sequence are mixed into intentionally polydispersed libraries. In particular, a three-component library and a four-component library are created to encode a 2-bytes model binary sequence. These 2D-coded libraries are incorporated in all commodity plastics via a simple solvent casting procedure. Furthermore, in all cases, the oligomer mixtures can be extracted from the host polymer films and deciphered by mass spectrometry, thus opening interesting avenues for anti-counterfeiting and traceability applications.
    Mots-clés : anti-counterfeiting technologies, building-blocks, design, Digital polymers, encoded polymers, information, information-containing macromolecules, macromolecules, oligomers, phase synthesis, phosphoramidite, sequence-controlled polymers, sequencing.

  • Konig, N. F.; Al Ouahabi, A.; Poyer, S.; Charles, L.; Lutz, J. - F. Angewandte Chemie-International Edition 2017, 56 (25), 7297–7301.
    Résumé : A three-step post-polymerization modification method was developed for the design of digitally encoded poly(phosphodiester)s with controllable side groups. Sequence-defined precursors were synthesized, either manually on polystyrene resins or automatically on controlled pore glass supports, using two phosphoramidite monomers containing either terminal alkynes or triisopropylsilyl (TIPS) protected alkyne side groups. Afterwards, these polymers were modified by stepwise copper-catalyzed azide-alkyne cycloaddition (CuAAC). The terminal alkynes were first reacted with a model azide compound, and after removal of the TIPS groups, the remaining alkynes were reacted with another organic azide. This simple method allows for quantitative side-chain modification, thus opening up interesting avenues for the preparation of a wide variety of digital polymers.
    Mots-clés : chemistry, containing macromolecules, cycloaddition, digitally encoded polymers, DNA, efficient, encoded oligomers, information-containing macromolecules, phosphoramidite, polymer modification, sequence-controlled polymers, sequence-defined oligomers, single, solid-phase synthesis, storage.

  • Konig, N. F.; Telitel, S.; Poyer, S.; Charles, L.; Lutz, J. - F. Macromolecular Rapid Communications 2017, 38 (24), 1700651.
    Résumé : A photoregulated phosphoramidite iterative process is studied for the synthesis of non-natural, digitally encoded oligo(phosphodiester)s. The oligomers are prepared using two reactive phosphoramidite monomers containing a 2-(2-nitrophenyl)propoxycarbonyl (NPPOC) protected OH group. The stepwise synthesis is performed on an OH-functional soluble polystyrene support, which allows recycling by precipitation in a nonsolvent. Repeating cycles involving phosphoramidite coupling, oxidation of phosphite to phosphate, and NPPOC deprotection by light irradiation at lambda = 365 nm are performed in order to prepare oligomers with different lengths and sequences. Synthesis is conducted on a micromolar scale and good recycling yields are obtained in all cases. The use of a soluble polymer support allows an in-depth characterization of the NPPOC photo-deprotection step by H-1 NMR, UV spectroscopy, and size exclusion chromatography, and thus identification of optimal synthesis conditions. After cleavage from the support, the oligo(phosphodiester)s are characterized by tandem mass spectrometry, which confirms preparation of uniform sequence-coded oligomers.
    Mots-clés : Digital polymers, encoded polymers, gene synthesis, information, macromolecules, microarrays, phosphoramidite chemistry, Photochemistry, protecting groups, sequence-controlled polymers, sequencing, soluble polymer support, soluble polymer supports.

  • Lassagne, A.; Beaudoin, E.; Ferrand, A.; Phan, T. N. T.; Davidson, P.; Iojoiu, C.; Bouchet, R. Electrochimica Acta 2017, 238, 21–29.
    Résumé : Block copolymer electrolytes (BCEs) are promising solid electrolytes in lithium metal batteries thanks to the versatility of the block chemistry. In this work, several triblock BCEs, based on a modified poly (ethylene oxide) (PEO) central block and two polystyrene (PS) lateral blocks, have been synthetized by controlled radical polymerization. By including few chemical defects homogeneously distributed along the PEO chains, we managed to break its stereo-regularity, which allows lowering significantly its melting temperature, and therefore obtaining good ionic conductivity at 40 degrees C. The mechanical properties were controlled by the length of the peripheral polystyrene blocks, which were varied from 2.9 to 11.3 kg/mol. We performed systematic analysis of morphologies, thermodynamic properties, mechanical properties, and ionic transport properties of these new BCEs that we compared to a triblock copolymer electrolyte based on a PEO central block. Finally, we characterized the performances of the BCE with the best compromise between mechanical strength and conductivity as electrolyte in a lithium metal battery using LiFePO4 as positive electrode active material. This device has been cycled at different rates from 40 degrees C to 80 degrees C with promising performances especially at 40 degrees C. (C) 2017 Elsevier Ltd. All rights reserved.
    Mots-clés : graft copolymer, high ionic-conductivity, high-performance, interfaces, ionic transport, lithium metal, molecular-weight, networks, peo, polymer electrolytes, saxs, state, transport.

  • Lescic, S.; Karoui, H.; Hardy, M.; Charles, L.; Tordo, P.; Ouari, O.; Gaudel-Siri, A.; Siri, D. Journal of Physical Organic Chemistry 2017, 30 (10), e3677.
    Résumé : Spin trapping coupled with electron paramagnetic resonance spectroscopy is the most direct method for detection of very low concentrations of free radicals, and it has been intensively used to detect superoxide or alkylperoxyl radicals in biological systems, using cyclic nitrones as spin traps. The half-life time of the ensuing spin adducts depends dramatically on the spin trap structure; however, their mechanism of decay has never been definitely established. We investigated at the MRMP2/CASSCF (MultiReference second-order Moller-Plesset perturbation theory/Complete Active Set Self Consistent Field) level of theory the mechanism of decay of methylperoxyl and tert-butylperoxyl spin adducts formed with various cyclic nitrones. We showed that no transition state can be located for the O-O homolytic cleavage, which yields an intermediate biradical with the following sequence O-center dot-N-C-O-center dot. Then, homolytic cleavage of the N-C bond yields a nitrosoaldehyde, through an early transition state with a very low activation energy. For each nitrone used as spin trap, electrospray ionization mass spectrometry analysis of the spin trapping mixture allowed to detect the presence of the expected nitrosoaldehyde. We generated tert-butylperoxyl spin adducts in toluene, and we found a good correlation between their half-life time and the bond dissociation energy of their peroxidic O-O bond. The theoretical method was then extended to hydroperoxyl spin adducts in water and provided promising results.
    Mots-clés : 2nd-order perturbation-theory, alkylperoxyl spin adducts, biradical, centered radicals, cyclic nitrones, depmpo, dft, dmpo, epr, half-life time, mrmp2/casscf, radical-anion adduct, spin trapping, superoxide, trapping properties.

  • Li, S.; Yang, X.; Niu, Y.; Andrew, G. L.; Bardelang, D.; Chen, X.; Wang, R. Chemistryselect 2017, 2 (7), 2219–2223.
    Résumé : Arecoline, as one of the major biologically active compounds extracted from Areca nut, has shown profound links to hepatotoxicity. In this study, the inclusion of arecoline hydrobromide (AH) in a synthetic receptor, cucurbit[7] uril (CB[7]), was demonstrated by (HNMR)-H-1 spectroscopic titration, isothermal titration calorimetry (ITC), electrospray ionization mass spectrometry (ESI-MS), and density functional theory (DFT) molecular modeling. The results showed that AH formed 1: 1 host-guest complexes with CB[7], with a binding constant K-a of 6.59 (+/- 0.23) x10(4) M-1, thermodynamically driven by both enthalpy (Delta H=-4.93 kcal mol(-1)) and entropy (TDS= 1.65 kcal mol(-1)). The hepatotoxicity of AH, when evaluated using MTT assay with a human liver cell line L02, was significantly alleviated (up to four times) upon its encapsulation by CB[7]. This discovery may lead to a novel AH formulation for improved safety of this natural product.
    Mots-clés : affinity, alzheimers-disease, areca nut, arecoline, complexation, drug-delivery, encapsulation, Hepatotoxicity, host-guest, host-guest interactions, in-vivo, inhibition, l02, macrocycles, zebrafish models.

  • Li, W.; Yin, H.; Bardelang, D.; Xiao, J.; Zheng, Y.; Wang, R. Food and Chemical Toxicology 2017, 109, 923–929.
    Résumé : Nitidine chloride (NC) has demonstrated promising anticancer activity. However, NC has also shown nonspecific toxicity in various healthy organs such as the liver. In this study, we aimed to develop a supramolecular formulation of NC and investigate the associated benefits of such a supramolecular formulation on modulating its inherent hepatotoxicity and anticancer activity. The formation of NC-cucurbit[7]uil (NC@CB[7]) complexes was characterized by H-1 nuclear magnetic resonance and Fourier transform infrared spectroscopy, differential scanning calorimetry and powder X-ray diffraction analysis. As a consequence of the supramolecular complexation, NC@CB[7] showed significantly lower toxicity (IC50: 6.87 +/- 0.80 mu M) on a liver cell line (LO2), and higher cytotoxicity (IC50: 2.94 +/- 0.15 mu M) on a breast cancer cell line (MCF-7), when compared with the free drug (IC50 of 3.48 +/- 0.49 mu M and 7.28 +/- 0.36 mu M, on these two cell lines, respectively). Investigation of cellular uptakes revealed that CB[7]'s capability in modulating the toxicity/activity of NC was mainly attributed to the drug's different cellular uptake behaviors that were influenced by CB[7]'s complexation. Taken together, we have demonstrated that supramolecular formulation of NC by CB(7] significantly alleviated its hepatotoxicity and improved its anticancer activity in vitro. (C) 2017 Elsevier Ltd. All rights reserved.
    Mots-clés : Anticancer activity, breast-cancer cells, cucurbituril, cucurbit[7], drug, encapsulation, Hepatotoxicity, in-vitro, Nitidine chloride, signaling pathway, solid-state, toxicity, uril Supramolecular formulation, vivo, zebrafish models.

  • Liao, W. - C.; Ong, T. - C.; Gajan, D.; Bernada, F.; Sauvee, C.; Yulikov, M.; Pucino, M.; Schowner, R.; Schwarzwalder, M.; Buchmeiser, M. R.; Jeschke, G.; Tordo, P.; Ouari, O.; Lesage, A.; Emsley, L.; Coperet, C. Chemical Science 2017, 8 (1), 416–422.
    Résumé : Dynamic Nuclear Polarization Surface Enhanced NMR Spectroscopy (DNP SENS) is an effective method to significantly improve solid-state NMR investigation of solid surfaces. The presence of unpaired electrons (polarizing agents) is crucial for DNP, but it has drawbacks such as leading to faster nuclear spin relaxation, or even reaction with the substrate under investigation. The latter can be a particular problem for heterogeneous catalysts. Here, we present a series of carbosilane-based dendritic polarizing agents, in which the bulky dendrimer can reduce the interaction between the solid surface and the free radical. We thereby preserve long nuclear T-2 of the surface species, and even successfully enhance a reactive heterogeneous metathesis catalyst.
    Mots-clés : biradicals, chemistry, complexes, dynamic nuclear-polarization, efficient, enhanced nmr-spectroscopy, metathesis catalysts, sites, sn-beta zeolite, tempo.

  • Martrou, G.; Leonetti, M.; Gigmes, D.; Trimaille, T. Polymer Chemistry 2017, 8 (11), 1790–1796.
    Résumé : We have here developed a straightforward one-step route to surface modified polystyrene (PS) based microfibers for protein/enzyme immobilization. Our approach consists of wet electrospinning of a poly(styrene-alt-maleic anhydride) (PSMA) polymer in an aqueous solution collector which contains the (macro) molecules to be coupled, here PEG diamine (PEGDA) or hexamethylene diamine (hexDA). The amino groups on the fiber surface were then exploited for immobilization of the horseradish peroxidase (HRP) enzyme. The immobilized HRP amounts were higher on the PEG-and hexyl-modified fibers than on the non-modified PSMA ones. The HRP catalytic activity was evaluated with 2,2'-azino-bis(3-ethyl-benzothiazoline- 6-sulfonic acid) (ABTS) as a substrate. While the retained activity of the enzyme immobilized on unmodified PSMA microfibers was only 2.4% of free enzyme, that of the enzyme immobilized on the PEGylated fibers increased to 34%. As a comparison, HRP fixed on hexyl-functionalized fibers exhibited a retention activity of 19.7%, showing the impact of a PEG spacer on HRP activity. HRP immobilization on PEG and hexyl-coated fibers had also a beneficial impact on enzyme storage stability. This study highlights the impact of surface properties on the activity of the immobilized enzyme and provides a convenient route to simultaneous elaboration/modification of fibers, for suitable protein fixation.
    Mots-clés : adsorption, cellulose fibers, enzyme immobilization, fabrication, horseradish-peroxidase, hydrogen-peroxide sensor, multilayer films, nanofibers, pegylated polyurethane nanoparticles, wet.

  • Masion, A.; Alexandre, A.; Ziarelli, F.; Viel, S.; Santos, G. M. Scientific Reports 2017, 7, 3430.
    Résumé : The determination of the chemical nature of the organic matter associated with phytoliths remains a challenge. This difficulty mainly stems from amounts of organic carbon (C) that are often well below the detection limit of traditional spectroscopic tools. Conventional solid-state C-13 Nuclear Magnetic Resonance (NMR) is widely used to examine the nature and structure of organic molecules, but its inherent low sensitivity prohibits the observation of diluted samples. The recent advent of commercial microwave source in the terahertz range triggered a renewed interest in the Dynamic Nuclear Polarization (DNP) technique to improve the signal to noise ratio of solid-state NMR experiments. With this technique, the C-13 spectrum of a phytolith sample containing 0.1% w/w C was obtained overnight with sufficient quality to permit a semi-quantitative analysis of the organic matter, showing the presence of peptides and carbohydrates as predominant compounds. Considering the natural abundance of the C-13 isotope, this experiment demonstrates that DNP NMR is sufficiently sensitive to observe spin systems present in amounts as low as a few tens of ppm.
    Mots-clés : c-13, carbon sequestration, high-frequency, magnetic-resonance spectra, matter, mineral associations, oxidative-degradation, phytoliths, soil carbon, spectroscopy.

  • Mathias, F.; Kabri, Y.; Crozet, M. D.; Vanelle, P. Synthesis-Stuttgart 2017, 49 (12), 2775–2785.
    Résumé : A one-pot sequential intramolecular cyclization and Suzuki-Miyaura or Sonogashira reaction under microwave irradiation are reported in the 5-nitro-2,3-dihydroimidazo[2,1-b]oxazole series. The intramolecular cyclization of 1-(2,4-dibromo-5-nitro-1H-imidazol-1yl)propan-2-ol between the hydroxyethyl group and the bromine atom at the 2-position is carried out first, followed by optimization and generalization of the Suzuki-Miyaura and Sonogashira cross-coupling reactions of the bromine atom at the 4-position. The various boronic acids and alkynyl derivatives used to perform these palladium-catalyzed cross-coupling reactions allowed to substitute the 6-position of 5-nitro-2,3- dihydroimidazo[2,1-b]oxazole compounds.
    Mots-clés : 5-nitroimidazole, anti-tb agents, cross-coupling reactions, dndi-vl-2098, in-vitro, intramolecular cyclization, microwave, nitroimidazoles, palladium, pharmacokinetics, potential radiosensitizing agents, series, Sonogashira reaction, Suzuki-Miyaura reaction, tuberculosis, visceral leishmaniasis.

  • Mathias, F.; Kabri, Y.; Okdah, L.; Di Giorgio, C.; Rolain, J. - M.; Spitz, C.; Crozet, M. D.; Vanelle, P. Molecules 2017, 22 (8), 1278.
    Résumé : A one-pot regioselective bis-Suzuki-Miyaura or Suzuki-Miyaura/Sonogashira reaction on 2,4-dibromo-1-methyl-5-nitro-1H-imidazole under microwave heating was developed. This method is applicable to a wide range of (hetero)arylboronic acids and terminal alkynes. Additionally, this approach provides a simple and efficient way to synthesize 2,4-disubstituted 5-nitroimidazole derivatives with antibacterial and antiparasitic properties.
    Mots-clés : 5-nitroimidazole, antibacterial, antiparasitic, bacteroides-fragilis, cross-coupling reactions, drug-resistance, giardia-duodenalis, halogenated nitrogen, helicobacter-pylori, metronidazole, microwave, nitroimidazoles, regioselectivity, Suzuki-Miyaura/Sonogashira, thioredoxin reductase, trichomonas-vaginalis.

  • Mokbel, H.; Anderson, D.; Plenderleith, R.; Dietlin, C.; Morlet-Savary, F.; Dumur, F.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Polymer Chemistry 2017, 8 (36), 5580–5592.
    Résumé : The goal of this paper concerns the development of photoinitiating systems usable in industrial processes for coating applications (cationic polymerization of epoxide based resins), the manufacture of Interpenetrating Polymer Networks (IPNs) (polymerization of acrylate/epoxy blends) and the production of thick epoxy/glass fibre composites. For these purposes, a copper photoredox catalyst, G1, is proposed as a high performance photoinitiator. It allows the design of very efficient three component photoinitiating systems (G1/iodonium salt (Iod)/N-vinylcarbazole (NVK)). The effects of the resin, light source (LED@ 375, 395, 405 nm, halogen lamp), G1 concentration, coating thickness (25 mu m and 1.4 mm), water content, formulation stability and hydrolytic stability of the cured coatings were investigated. Examples of IPNs and glass fibre composites are provided. In the studied applications the G1/Iod/NVK system is much better than BAPO/Iod/NVK (BAPO -bis(2,4,6-trimethylbenzoyl) phenylphosphine oxide -Irgacure 819) used as a reference system with good reactivity in the 365-420 nm range. Owing to the catalytic nature of G1, a reduced G1 content (30 fold less compared to the BAPO content) still leads to a higher practical efficiency than BAPO in the photopolymerization of a coating. A comparison with other reference systems based on 2-isopropylthioxanthone or anthracene is also provided and outlines again the very high performance of G1 for industrial applications.
    Mots-clés : air, cationic-polymerization, combination, complexes, initiating systems, light, monomers, photopolymerization.

  • Mousslim, M.; Pagano, A.; Andreotti, N.; Garrouste, F.; Thuault, S.; Peyrot, V.; Parat, F.; Luis, J.; Culcasi, M.; Thetiot-Laurent, S.; Pietri, S.; Sabatier, J. - M.; Kovacic, H. European Journal of Pharmacology 2017, 794, 162–172.
    Résumé : The NADPH oxidase proteins catalyse the formation of superoxide anion which act as signalling molecules in physiological and pathological processes. Nox1-dependent NADPH oxidase is expressed in heart, lung, colon, blood vessels and brain. Different strategies involving Nox1 inhibition based on diphenylene iodonium derivatives are currently tested for colorectal cancer therapy. Here, after peptides screening on Nox1-dependent NADPH oxidase assay in HT-29 cells, we identify a peptide (referred to as NF02), cell-active, that potently block Nox1-dependent reactive oxygen species generation. Study of DEPMPO adduct formation by electron paramagnetic resonance showed that NF02 has no superoxide scavenging activity and no impact on cellular reactive oxygen species-producing enzymes such xanthine oxidase. NF02 was not cytotoxic, inhibited reactive oxygen species production of reconstituted Nox1/Noxo1/Noxa1 complex in HEK293 and did not decrease Nox2 dependent cellular NADPH oxidase reactive oxygen species production. Finally, NF02 inhibited cell migration and invasion of colorectal cancer cells which is consistent with the described impact of Nox1 inhibitors on cell migration. NF02 peptide is a new NADPH oxidase inhibitor specific for Nox1 over Nox2 and xanthine oxidase which might represent a useful Nox1 tool with potential therapeutic insights.
    Mots-clés : 5-(diethoxyphosphoryl)-5-methyl-1-pyrroline n-oxide, activation, Cell migration, colon-cancer-cells, EPR spin trapping, expression, flavin dehydrogenase inhibitors, functional invadopodia, mechanisms, NADPH oxidase, nox family, Nox1, Reactive oxygen species, superoxide, superoxide-generating oxidase, synthetic peptides.

  • Mouysset, D.; Tessonnier, C.; Tintaru, A.; Dumur, F.; Jean, M.; Vanthuyne, N.; Bertrand, M. P.; Siri, D.; Nechab, M. Chemistry-a European Journal 2017, 23 (35), 8375–8379.
    Résumé : Enantioenriched indenes were reached through a chirality conversion strategy using original axially chiral benzylidene cyclanes. Good to high remote diastereocontrol and excellent enantiocontrol were observed in this cascade involving copper-catalyzed homologation of terminal alkynes, in situ allenoate formation and Alder-ene cyclization.
    Mots-clés : 1-methylcyclohexylidene-4-acetic acid, asymmetric synthesis, asymmetric-synthesis, bearing, c-h functionalization, carbocycles, catalyst, chirality, cyclization, enantioselective synthesis, ene reaction, enediynes, indanes.

  • Nehache, S.; Tyagi, P.; Semsarilar, M.; Deratani, A.; Phan, T. N. T.; Gigmes, D.; Quemener, D. Soft Matter 2017, 13 (38), 6689–6693.
    Résumé : Herein, a membrane prepared from the self-assembly of poly(styreneco-acrylonitrile)-b-poly(ethyleneoxide)-b-poly(styrene-co-acrylonitrile) micelles is found to exhibit translocation of nano-objects dispersed in aqueous solution. With the water flow as a driving force, temporary pores are created in between the micelles to facilitate the passage of nano-objects. These temporary pores close afterwards through a self-healing mechanism. As main results, polystyrene and silica nanoparticles exhibited a selective translocation directly influenced by their size and applied pressure.
    Mots-clés : adsorption, bilayer, carbon nanotubes, delivery, nanoparticles, protein, serum-albumin, surfaces.

  • Nkolo, P.; Audran, G.; Bikanga, R.; Bremond, P.; Marque, S. R. A.; Roubaud, V. Organic & Biomolecular Chemistry 2017, 15 (29), 6167–6176.
    Résumé : Throughout the last decade, the effect of electron withdrawing groups (EWGs) has been known to play a role - minor or moderate depending on the nitroxyl fragment R1R2NO - in the change in the homolysis rate constant (k(d)) for C-ON bond homolysis in alkoxyamines (R1R2NOR). It has been shown that the effect of EWGs on k(d) is described by a linear relationship with the electrical Hammett constant sigma(1). Since then, linear multi-parameter relationships f (sigma(RS),nu,sigma(1)) have been developed to account for the effects involved in the changes in k(d), which are the stabilization of the released radical (sigma(RS)) and the bulkiness (nu) and polarity (sigma(1)) of the alkyl fragment. Since a decade ago, new results have been published highlighting the limits of such correlations. In this article, previous multi-parameter linear relationships are amended using a parabolic model, i.e. (sigma(1,nitroxide) - sigma(1,alkyl))(2), to describe the effect of EWGs in the alkyl fragment on kd. In contrast to previous studies, these improved linear multi-parameter relationships f (sigma(RS,)nu,Delta sigma(2)(1)) are able to account for the presence of several EWGs on the alkyl fragment, R. An unexpectedly strong solvent effect - a ca. 1500-fold increase in k(d) - from tert-butylbenzene to the water/methanol mixture is also observed for 3-((2,2,6,6-tetramethylpiperidin-1-yl)oxyl)pentane-2,4-dione 1b in comparison to a ca. 5-fold increase in k(d) that is generally observed.
    Mots-clés : agents, family, free-energy relationships, nitroxyl fragment, polymers, radical polymerization, rate-constant.

  • Nkolo, P.; Audran, G.; Bremond, P.; Bikanga, R.; Marque, S. R. A.; Roubaud, V. Tetrahedron 2017, 73 (23), 3188–3201.
    Résumé : Solvent effects in beta-phosphorylated nitroxides show that nitrogen and phosphorus hyperfine coupling constants a(N) and a(p), increase and decrease with increasing polarity, polarizity, and Hydrogen Bond Donor effects of solvents, respectively. In a series of articles, it was shown that the driving interaction controlling the change in a(p) is the maximization of the N+center dot O-center dot center dot center dot center dot center dot center dot P+-O- dipole - dipole interaction. In this work, we show that the steric strain in Spiro beta-phosphotylated nitroxides affords the opposite trend for a(p) that is, a(p) increases with increasing solvent properties features. (C) 2017 Elsevier Ltd. All rights reserved.
    Mots-clés : electron-transfer, EPR spectroscopy, esr, mri, Multi-parameter analysis, nitrogen, Nitroxides, parameter, probes, resonance, solvation, Solvent effect, solvent polarity.

  • Orozco-Gonzalez, Y.; Manathunga, M.; Marin, M. del C.; Agathangelou, D.; Jung, K. - H.; Melaccio, F.; Ferre, N.; Haacke, S.; Coutinho, K.; Canuto, S.; Olivucci, M. Journal of Chemical Theory and Computation 2017, 13 (12), 6391–6404.
    Résumé : A novel atomistic methodology to perform free energy geometry optimization of a retinal chromophore covalently bound to any rhodopsin-like protein cavity is presented and benchmarked by computing the absorption maxima wavelengths (lambda(max)) of distant rhodopsin systems. The optimization is achieved by computing the Nagaoka's Free Energy Gradient (FEG) within an Average Solvent Electrostatic Configuration (ASEC) atomistic representation of the thermodynamic equilibrium and minimizing such quantity via an iterative procedure based on sequential classical MD and constrained QM/MM geometry optimization steps. The performance of such an ASEC-FEG protocol is assessed at the CASPT2//CASSCF/Amber level by reproducing the lambda(max) values observed for 12 mutants of redesigned human cellular retinol binding protein II (hCRBPII) systems; a set of 10 distant wild-type rhodopsins from vertebrates, invertebrates, eubacteria, and archaea organisms; and finally a set of 10 rhodopsin mutants from an eubacterial rhodopsin. The results clearly show that the proposed protocol, which can be easily extended to any protein incorporating a covalently bound ligand, yields correct lambda(max) trends with limited absolute errors.
    Mots-clés : 77 k, anabaena sensory rhodopsin, aqueous-solution, crystal-structure, gradient-method, high-throughput, hydrogen-bond, molecular-mechanism, sequential qm/mm, transition-state optimization.

  • Pannequin, A.; Tintaru, A.; Desjobert, J. - M.; Costa, J.; Muselli, A. Flavour and Fragrance Journal 2017, 32 (6), 409–418.
    Résumé : The chemical composition of Frullania tamarisci essential oil from Corsica was investigated using GC-FID, GC-MS and NMR analyses. The essential oil compositions were further studied analyzing samples prepared from three different Corsican locations and during a seasonal vegetative cycle. 40 components, which accounted for 78.3-89.8% of the total amount of F. tamarisci essential oils were identified. The main components were tamariscol coeluted with pacifigorgiol (30.4-41.5%), germacra-1(10)E,5E-dien-11-ol (3.6-7.1%), gamma-cylocostunolide (1.8-20.1%), gamma-dihydrocyclocostunolide (1.2-8.0%) and frullanolide (1.7-4.9%). Among them, germacra-1(10)E,5E-dien-11-ol was never reported in the Frullania genus and pacifigorgiol, a tamariscol GC-overlapped compound, was for the first time reported in Bryophytes. Finally using 1D and 2D NMR experiments, we reported gamma-dihydrocyclocostunolide as a new natural compound. Two Corsican F. tamarisci essential oils with different GC profiles were assessed for their phytotoxic behavior against onion seeds and seedling in order to evaluate their capacity to inhibit germination and alter the development of plantlets. According to the essential oil-compositions, a stimulation of the onion seedling was observed when sesquiterpene lactones amount was higher, whilst the inhibition of roots growth occurs when sesquiterpene alcohols were predominantly.
    Mots-clés : alcohol, allelopathy, bryophytes, chemical-constituents, chemosystematics, components, corsica, essential oil, essential oil composition, Frullania tamarisci, gamma-Dihydrocyclocostunolide, hepaticae, sesquiterpene lactones, tamariscol, valeriana-officinalis, witchweed germination.

  • Popova, N. A.; Sysoeva, G. M.; Nikolin, V. P.; Kaledin, V. I.; Tretyakov, E. V.; Edeeva, M. V.; Balakhnin, S. M.; Lushnikova, E. L.; Audran, G.; Mark, S. Bulletin of Experimental Biology and Medicine 2017, 164 (1), 49–53.
    Résumé : Effect of alkoxyamines on normal and tumor cells was studied in vitro and in vivo. In vitro experiments showed that alkoxyamines produce a dose-dependent toxic effect on cells of human breast tumor MCF7 line. Transplantation of Krebs-2 ascites carcinoma cells preincubated with alkoxyamines to mice did not induce tumor growth. An opposite effect was observed in normal mouse cells: functional activity of peritoneal macrophages increased. The possibility of using alkoxyamines as theranostic agents is discussed.
    Mots-clés : alkoxyamines, cancer, model, phagocytic activity of peritoneal macrophages, therapy, toxicity, transplanted tumor strains, tumor, tumor cell lines.

  • Poulhes, F.; Rizzato, E.; Bernasconi, P.; Rosas, R.; Viel, S.; Jicsinszky, L.; Rockenbauer, A.; Bardelang, D.; Siri, D.; Gaudel-Siri, A.; Karoui, H.; Hardy, M.; Ouari, O. Organic & Biomolecular Chemistry 2017, 15 (30), 6358–6366.
    Résumé : Three new DEPMPO-based spin traps have been designed and synthesized for improved superoxide detection, each carrying a cyclodextrin (CD) moiety but with a different alkyl chain on the phosphorus atom or with a long spacer arm. EPR spectroscopy allowed us to estimate the half-life of the superoxide spin adducts which is close to the value previously reported for CD-DEPMPO (t(1/2) approximate to 50-55 min under the conditions investigated). The spectra are typical of superoxide adducts (almost no features of the HO center dot adduct that usually forms with time for other nitrone spin traps such as DMPO) and we show that at 250 mu M, the new spin trap enables the reliable detection of superoxide by 1 scan at the position opposite to the corresponding spin trap without the CD moiety. The resistance of the spin adducts to a reduction process has been evaluated, and the superoxide spin adducts are sensitive to ascorbate and glutathione (GSH), but not to glutathione peroxidase/GSH, reflecting the exposed nature of the nitroxide moiety to the bulk solvent. To understand these results, 2D-ROESY NMR studies and molecular dynamics pointed to a shallow or surface self-inclusion of the nitrone spin traps and of nitroxide spin adducts presumably due to the high flexibility of the permethyl-beta-CD rim.
    Mots-clés : conjugate, cyclic nitrone, depmpo, epr, in-vivo, inclusion, metabolic stability, radical adducts, resonance, trapping properties.

  • Redon, S.; Roly, A.; Kosso, O.; Broggi, J.; Vanelle, P. Tetrahedron Letters 2017, 58 (28), 2771–2773.
    Résumé : The regioselective selenocyanation of imidazoheterocycles using triselenodicyanide at room temperature is reported. The electrophilic aromatic substitution of a broad range of substrates is promoted by the triselenodicyanide obtained by oxidative coupling of malononitrile and selenium dioxide, under an air atmosphere. The major advantages of the presented method are an easy set-up, excellent yields, short reaction times, use of odorless and inexpensive reagents and easy purification of the final products. (C) 2017 Elsevier Ltd. All rights reserved.
    Mots-clés : aqueous-medium, derivatives, diselenides, Imidazoheterocycles, Malononitrile, potent antileishmanial agents, salts, Selenium dioxide, Selenocyanate, Triselenodicyanide.

  • Salian, G. D.; Lebouin, C.; Demoulin, A.; Lepihin, M. S.; Maria, S.; Galeyeva, A. K.; Kurbatov, A. P.; Djenizian, T. Journal of Power Sources 2017, 340, 242–246.
    Résumé : We report that electrodeposition of polymer electrolyte in nanostructured electrodes has a strong influence on the electrochemical properties of thin-film Li-ion microbatteries. Electropolymerization of PMMA-PEG (polymethyl methacrylate-polyethylene glycol) was carried out on both the anode (self-supported titania nanotubes) and the cathode (porous LiNi0.5Mn1.5O4) by cyclic voltammetry and the resulting electrode-electrolyte interface was examined by scanning electron microscopy. The electrochemical characterizations performed by galvanostatic experiments reveal that the capacity values obtained at different C-rates are doubled when the electrodes are completely filled by the polymer electrolyte. (C) 2016 Elsevier B.V. All rights reserved.
    Mots-clés : batteries, Electrodeposition, electropolymerization, high-energy, Li-ion microbatteries, mechanism, Polymer electrolyte, Porous materials, tio2 nanotube electrodes, titania nanotubes.

  • Sikora, A.; Michalski, R.; Hardy, M.; Ouari, O.; Adamus, J.; Marcinek, A.; Zielonka, J.; Kalyanaraman, B. Free Radical Biology and Medicine 2017, 108, S38–S38.
    Mots-clés : hydroethidine, superoxide radical anion.

  • Spitz, C.; Giuglio-Tonolo, A. G.; Terme, T.; Vanelle, P. Molecules 2017, 22 (7), 1178.
    Résumé : A mild and metal-free regiodivergent addition of carbon nucleophiles to alpha,beta-unsaturated electrophiles was developed. Total 1,2-regioselectivity was observed in the addition of nitrobenzyl chloride derivative 1 to alpha,beta-unsaturated aldehydes 2 in the presence of TDAE. Moreover, the reaction between p-nitrobenzyl chloride 1a and alpha,beta -unsaturated iminium salts 4 led to the formation of the 1,4-adduct with total regioselectivity.
    Mots-clés : aldehydes, alpha, beta-unsaturated electrophiles, diastereoselective synthesis, imines, metal-free, mild, n-tert-butanesulfinylamines, original synthesis, p-nitrobenzyl chloride, regiodivergent, strategy, tdae approach, tetrakis(dimethylamino)ethylene.

  • Stenrup, M.; Pieri, E.; Ledentu, V.; Ferre, N. Physical Chemistry Chemical Physics 2017, 19 (21), 14073–14084.
    Résumé : A minimal electrostatic model is introduced which aims at reproducing and analyzing the visible- light absorption energy shift of a protein with pH. It relies on the existence of a protein structure, the prediction of titratable amino-acid pKa values and a very limited set of parameters. Applied to the case of the photochromic Anabaena sensory rhodopsin protein, the model succeeds in reproducing qualitatively the reported experimental data, confirming the importance of aspartic acid 217 in the observed blue shift in the lambda(max) of ASR at neutral pH. It also suggests for the first time the role of two other amino acids, glutamic acid 36 at basic pH and aspartic acid 120 at acidic pH.
    Mots-clés : bacteriorhodopsin, chromophore, energy-storage, mechanism, membrane-protein, photocycle, pk(a) values, qm/mm, retinal proteins, schiff-base.

  • Stocker, P.; Cassien, M.; Vidal, N.; Thetiot-Laurent, S.; Pietri, S. Talanta 2017, 170, 119–127.
    Résumé : Myeloperoxidase (MPO) is a key enzyme derived from leukocytes which is associated with the initiation and progression of many inflammatory diseases. Increased levels of MPO may contribute to cellular dysfunction and tissues injury by producing highly reactive oxidants such as hypochlorous acid (HOCl). Myeloperoxidase-generated HOCl is therefore considered as a relevant biomarker of oxidative stress-related damage and its quantitation is of great importance to the study of disease progression. In this context, the current study describes a rapid, sensitive and homogeneous fluorescence-based method for detecting the MPO chlorination activity in biological samples. This assay utilizes 7-hydroxy-2-oxo-2H-chromene-8-carbaldehyde oxime as a selective probe for HOCl detection, and is adapted to 96-well microplates to allow high-throughput quantitation of active MPO. The ability of the method to monitor HOCl release was further investigated in hyperglycemic streptozotocin-treated diabetic rats. The data proved that the present assay has a reliable performance when quantitating the active MPO in the plasma of diabetic animals, a feature of inflammatory disease found concomitant with an elevation of protein carbonyls levels and lipid peroxidation and which was negatively correlated with the ratio of reduced-to-oxidized glutathione.
    Mots-clés : 3-chlorotyrosine, 7-hydroxy-2-oxo-2H-chromene-8-carbaldehyde oxime, antioxidant, atherosclerosis, Fluorimetric assay, glutathione synthesis, hypochlorous acid, Myeloperoxidase, myocardial-infarction, nephropathy, oxidants, plasma, stress.

  • Stojanovic, L.; Aziz, S. G.; Hilal, R. H.; Plasser, F.; Niehaus, T. A.; Barbatti, M. Journal of Chemical Theory and Computation 2017, 13 (12), 5846–5860.
    Résumé : We implemented a version of the decoherence-corrected fewest switches surface hopping based on linear-response time-dependent density functional tight binding (TD-DFTB), enhanced by transition density analysis. The method has been tested for the gas-phase relaxation dynamics of two cycloparaphenylene molecules, [8]CPP and [10]CPP, explaining some important features of their nonadiabatic dynamics, such as the origin of their long fluorescence lifetimes (related to the slow radiative emission from the S-1 state) and the trend of increasing the fluorescence rate with the molecular size (related to an increase in the S-1-S-0 energy gaps and oscillator strengths in the larger molecule). The quality of the TD-DFTB electronic structure information was assessed through four quantities: excitation energies; charge-transfer (CT) numbers, which estimate the charge transfer character of states; participation ratio (PR), which describes delocalization of electronic density; and participation ratio of natural transition orbitals (PRNTO), which describes the multiconfigurational character of states. These quantities were computed during dynamics and recomputed for the same geometries with the higher-level long-range-corrected TD-LC-DFTB and a lower-level single-determinant approximation for the excited states, SD-(LC)-DFTB. Taking TD-LC-DFTB as the standard, TD-DFTB underestimates the excitation energies by similar to 0.5 eV and overestimates CT and PR. SD-DFTB underestimates excitation energies and overestimates CT to the same extent that TD-DFTB does, but it predicts reasonable PR distributions. SD-LC-DFTB leads to an extreme overestimation of the excitation energies by similar to 3 eV, overestimates the charge transfer character of the state, but predicts the PR values very close to those obtained with TD-LC-DFTB.
    Mots-clés : ab-initio calculations, carbon, charge-transfer, density-functional-theory, energy-transfer processes, excited-states, molecular-dynamics, polymers, systems, tight-binding method.

  • Szweda, R.; Chendo, C.; Charles, L.; Baxter, P. N. W.; Lutz, J. - F. Chemical Communications 2017, 53 (59), 8312–8315.
    Résumé : Due to their strong tendency to self-aggregate, unfunctionalized oligoarylacetylenes are difficult to synthesize. Here, tailored polystyrene soluble supports, prepared by atom transfer radical polymerization and post-polymerization modification, were tested for preparing sequence-defined oligoarylacetylenes. Controlled aromatic sequences were obtained by iterative Sonogarisha coupling, using phenyl- and pyridine-based building-blocks.
    Mots-clés : block-copolymers, encoded polymers, hydrolysis, liquid-phase synthesis, macromolecules, nanoarchitectures, oligomers, organic-synthesis, phosphoramidite chemistry, transfer radical polymerization.

  • Tarbe, M.; de Pomyers, H.; Mugnier, L.; Bertin, D.; Ibragimov, T.; Gigmes, D.; Mabrouk, K. Fitoterapia 2017, 120, 85–92.
    Résumé : Aconitum karacolicum from northern Kyrgyzstan (Alatau area) contains about 0.8-1% aconitine as well as other aconite derivatives that have already been identified. In this paper, we compare several methods for the further purification of an Aconitum karacolicum extract initially containing 80% of aconitine. Reverse-phase flash chromatography, reverse-phase semi-preparative HPLC, centrifugal partition chromatography (CPC) and re crystallization techniques were evaluated regarding first their efficiency to get the highest purity of aconitine (over 96%) and secondly their applicability in a semi-industrial scale purification process (in our case, 150 g of plant extract). Even if the CPC technique shows the highest purification yield (63%), the recrystallization remains the method of choice to purify a large amount of aconitine as i) it can be easily carried out in safe conditions; ii) an aprotic solvent is used, avoiding aconitine degradation. Moreover, this study led us to the identification of lappaconitine in Aconitwn karacolicum, a well-known alkaloid never found in this Aconttum species.
    Mots-clés : Aconinun karacolicum, Aconitine, Aconitine degradation, alkaloids, counter-current chromatography, Lappaconitine, Plant extract, Purification methods, separation.

  • Tardy, A.; Honore, J. - C.; Siri, D.; Nicolas, J.; Gigmes, D.; Lefay, C.; Guillaneuf, Y. Polymer Chemistry 2017, 8 (34), 5139–5147.
    Résumé : The current study reports on the kinetic analysis of the free-radical polymerization of several seven-membered cyclic ketene acetal monomers and in particular 2-methylene-1,3-dioxepane (MDO) and 5,6-benzo-2-methylene-1,3-dioxepane (BMDO). Such monomers are known to undergo a complete ring-opening to afford polyester chains by a radical pathway. The influence of experimental conditions (e.g., nature and concentration of the initiator, temperature, solvent, etc.) on the kinetics and molar mass distribution was studied. Whereas it was shown that BMDO cannot be polymerized using peroxides due to H-abstraction, the experimental results also demonstrated that the polymerization kinetics were strongly driven by the nature of the propagating radical, with reactivity order: MDO \textgreater BMDO \textgreater 4,7-dimethyl-5,6-benzo-2(chloromethyl)-1,3-dioxepane (MeBMDO). The copolymerization of MDO and BMDO (1 : 1) was also investigated. The incorporation of both monomers was identical but the polymerization kinetics were governed by the monomer with the lowest reactivity. The experimental results were finally rationalized by the combination of DFT calculations of the propagation rate constants with PREDICI modelings.
    Mots-clés : 2-methylene-1, 3-dioxepane, 5, 6-benzo-2-methylene-1, copolymers, limitations, mechanism, methacrylate, polyester, rate coefficients, ring-opening polymerization, styrene.

  • Tardy, A.; Honore, J. - C.; Tran, J.; Siri, D.; Delplace, V.; Bataille, I.; Letourneur, D.; Perrier, J.; Nicoletti, C.; Maresca, M.; Lefay, C.; Gigmes, D.; Nicolas, J.; Guillaneuf, Y. Angewandte Chemie-International Edition 2017, 56 (52), 16515–16520.
    Résumé : Free-radical copolymerization of cyclic ketene acetals (CKAs) and vinyl ethers (VEs) was investigated as an efficient yet simple approach for the preparation of functional aliphatic polyesters. The copolymerization of CKA and VE was first predicted to be quasi-ideal by DFT calculations. The theoretical prediction was experimentally confirmed by the copolymerization of 2-methylene-1,3-dioxepane (MDO) and butyl vinyl ether (BVE), leading to r(MDO) = 0.73 and r(BVE) = 1.61. We then illustrated the versatility of this approach by preparing different functional polyesters: 1) copolymers functionalized by fluorescent probes; 2) amphiphilic copolymers grafted with poly(ethylene glycol) (PEG) side chains able to self-assemble into PEGylated nanoparticles; 3) antibacterial films active against Gram-positive and Gram-negative bacteria (including a multiresistant strain); and 4) cross-linked bioelastomers with suitable properties for tissue engineering applications.
    Mots-clés : 2-methylene-1, 3-dioxepane, aliphatic polyesters, biodegradable polyesters, biomaterials, biomedical applications, caprolactone, click chemistry, combination, copolymerization, cyclic ketene acetals, degradable polymers, DFT calculations, functional polyesters, ring-opening polymerization.

  • Tardy, A.; Nicolas, J.; Gigmes, D.; Lefay, C.; Guillaneuf, Y. Chemical Reviews 2017, 117 (3), 1319–1406.
    Résumé : Cyclic monomers bearing either vinyl or exomethylene groups have the ability to be polymerized through a radical pathway via a ring-opening mechanism (addition fragmentation process), leading to the introduction of functionalities in the polymer backbone. Radical ring-opening polymerization (rROP) combines the advantages of both ring-opening polymerization and radical polymerization, that is the preparation of polymers bearing heteroatoms in the backbone but with the ease and robustness of a radical process. This current review presents a comprehensive description of rROP by detailing: (0 the various monomers that polymerize through rROP; (ii) the main parameters that govern the rROP mechanism; (iii) the copolymerization by conventional or controlled/living radical polymerization between rROP monomers and traditional vinyl monomers to obtain copolymers with advanced properties; (iv) the different applications (low shrinkage materials and pieparation of (bio)degradable materials) of rROP monomer-containing materials, and (v) the main alternatives to rROP to induce degradability to materials obtained by a radical polymerization.
    Mots-clés : conventional vinyl monomers, cyclic ketene acetals, fragmentation chain transfer, functional degradable polymers, holographic data-storage, intracellular drug-delivery, methacrylate) based polymers, Nitroxide-mediated polymerization, poly(4-hydroxystyrene)s main-chain, tissue engineering applications.

  • Tehfe, M. - A.; Lepeltier, M.; Dumur, F.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Macromolecular Chemistry and Physics 2017, 218 (18), 1700192.
    Résumé : A series of 18 iridium complexes (Ir) have been prepared and studied. Their abilities to initiate both a ring-opening cationic polymerization (CP) using an Ir/iodonium salt couple and a free radical polymerization (FRP) in the presence of an Ir/amine/alkyl halide system under very soft irradiation (i.e., halogen lamp) or upon exposure to laser diodes @457 nm and @532 nm are investigated. Interestingly, these photoinitiating systems operate through an oxidative or a reductive photoredox catalytic cycle, respectively. Excellent polymerization profiles are obtained (reactive function conversions \textgreater70% for the CP of an epoxide and \textgreater60% for the FRP of low viscosity triacrylate). The photochemical mechanisms are studied by fluorescence, steady state photolysis, cyclic voltammetry, and electron spin resonance spin trapping experiments.
    Mots-clés : atom-transfer, atrp, cationic-polymerization, electron, Free radical polymerization, initiator, iridium complexes, led, metal, photocatalysis, photopolymerization, radical polymerization, ring-opening cationic polymerization (ROP), systems.

  • Telitel, S.; Petit, B. E.; Poyer, S.; Charles, L.; Lutz, J. - F. Polymer Chemistry 2017, 8 (34), 4988–4991.
    Résumé : Sequence-coded oligourethanes were tested as macroinitiators for the atom transfer radical polymerization (ATRP) of styrene. These oligomers were synthesized by solid-phase orthogonal iterative chemistry and transformed into ATRP initiators using a three-step modification procedure. A controlled radical polymerization behavior was observed with these macroinitiators, thus opening interesting opportunies for the synthesis of macromolecular architectures containing sequence-defined segments.
    Mots-clés : block-copolymers, initiators, phosphoramidite, polymers, transfer radical polymerization.

  • Tesfaye, A. T.; Yucel, Y. D.; Barr, M. K. S.; Santinacci, L.; Vacandio, F.; Dumur, F.; Maria, S.; Monconduit, L.; Djenizian, T. Electrochimica Acta 2017, 256, 155–161.
    Résumé : Evolution of the electrical and morphological properties of micron-sized SnSb has been investigated to understand the electrochemical behavior observed during cycling experiments. Electron microscopy techniques (scanning electron microscopy and transmission electron microscopy) and electrochemical impedance spectroscopy have been combined to evidence the electrode modifications and particularly the formation of a solid electrolyte interphase (SEI) layer. Evolution of the SEI resistance and the charge transfer resistance with the cell voltage can be explained by the electrolyte degradation and expansion/contraction of the electrode. Furthermore, we show that the SEI formation is not limited at the first discharge/charge of the battery. The continuous growth of the SEI layer up to 50 cycles associated to the electrode pulverization caused by the large volume variations are responsible for the capacity fading. (C) 2017 Elsevier Ltd. All rights reserved.
    Mots-clés : additives, chemistry, Electrochemical Impedance Spectroscopy, Electron Microscopy, graphite, interphase, Li-ion Batteries, lithium intercalation, morphology, sei, SnSb, Solid Electrolyte Interphase, solid-electrolyte, tin-based intermetallics, tisnsb.

  • Thetiot-Laurent, S.; Gosset, G.; Clement, J. - L.; Cassien, M.; Mercier, A.; Siri, D.; Gaudel-Siri, A.; Rockenbauer, A.; Culcasi, M.; Pietri, S. Chembiochem 2017, 18 (3), 300–315.
    Résumé : There is increasing interest in measuring pH in biological samples by using nitroxides with pH-dependent electron paramagnetic resonance (EPR) spectra. Aiming to improve the spectral sensitivity (Delta a(x)) of these probes (i.e., the difference between the EPR hyperfine splitting (hfs) in their protonated and unprotonated forms), we characterized a series of novel linear alpha-carboxy, alpha'-diethoxyphosphoryl nitroxides constructed on an amino acid core and featuring an (alpha or alpha')-C-H bond. In buffer, the three main hfs (a(N), a(H), and a(P)) of their EPR spectra vary reversibly with pH and, from a(P) or a(H) titration curves, a two-to fourfold increase in sensitivity was achieved compared to reference imidazoline or imidazolidine nitroxides. The crystallized carboxylate 10b (pK(a) approximate to 3.6), which demonstrated low cytotoxicity and good resistance to bioreduction, was applied to probe stomach acidity in rats. The results pave the way to a novel generation of highly sensitive EPR pH markers.
    Mots-clés : EPR spectroscopy, intracellular ph, living cells, magnetic-resonance, molecular dynamics, n-oxide, nitroxide, oxidative stress, p-31 nmr, rat-liver, ring nitroxides, sensors, spin labels, stomach acidity, substituted nitroxides.

  • Toldo, J. M.; Barbatti, M.; Goncalves, P. F. B. Physical Chemistry Chemical Physics 2017, 19 (29), 19103–19108.
    Résumé : A three-state model for the photo-Fries rearrangement (PFR) is proposed based on multiconfigurational calculations. It provides a comprehensive mechanistic picture of all steps of the reaction, from the photoabsorption to the final tautomerization. The three states participating in the PFR are an aromatic (1)pi pi*, which absorbs the radiation; a pre-dissociative (1)n pi*, which transfers the energy to the dissociative region; and a (1)pi sigma*, along which dissociation occurs. The transfer from (1)pi pi* to (1)n pi* involves pyramidalization of the carbonyl carbon, while transfer from (1)n pi* to (1)pi sigma* takes place through CO stretching. Different products are available after a conical intersection with the ground state. Among them is a recombined radical intermediate, which can yield ortho-PFR products after an intramolecular 1,3-H tunneling. The three-state model is developed for phenyl acetate, the basic prototype for the PFR, and it reconciles the theory with a series of observations from time-resolved spectroscopy. It also delivers a rational way to optimize PFR yields, since, as shown for four different systems, diverse substituents can change the energetic order of the (1)pi pi* and (1)n pi* states, preventing or enhancing the PFR.
    Mots-clés : 1, 1-naphthyl acetate, 5-sigmatropic hydrogen shifts, aromatic esters, aryl esters, laser flash-photolysis, mfe probe, perturbation-theory, phenyl acetate, photochemical primary process, refractive-index modulation.

  • Tranchida, F.; Rakotoniaina, Z.; Shintu, L.; Tchiakpe, L.; Deyris, V.; Yemloul, M.; Stocker, P.; Vidal, N.; Rimet, O.; Hiol, A.; Caldarelli, S. Scientific Reports 2017, 7 (1).
    Résumé : The metabolic effects of an oral supplementation with a Curcuma longa extract, at a dose nutritionally relevant with common human use, on hepatic metabolism in rats fed a high fructose and saturated fatty acid (HFS) diet was evaluated. High-resolution magic-angle spinning NMR and GC/MS in combination with multivariate analysis have been employed to characterize the NMR metabolite profiles and fatty acid composition of liver tissue respectively. The results showed a clear discrimination between HFS groups and controls involving metabolites such as glucose, glycogen, amino acids, acetate, choline, lysophosphatidylcholine, phosphatidylethanolamine, and β-hydroxybutyrate as well as an increase of MUFAs and a decrease of n-6 and n-3 PUFAs. Although the administration of CL did not counteract deleterious effects of the HFS diet, some metabolites, namely some n-6 PUFA and n-3 PUFA, and betaine were found to increase significantly in liver samples from rats having received extract of curcuma compared to those fed the HFS diet alone. This result suggests that curcuminoids may affect the transmethylation pathway and/or osmotic regulation. CL extract supplementation in rats appears to increase some of the natural defences preventing the development of fatty liver by acting on the choline metabolism to increase fat export from the liver.

  • Vibert, F.; Bloch, E.; Bertrand, M. P.; Queyroy, S.; Gastaldi, S.; Besson, E. New Journal of Chemistry 2017, 41 (14), 6678–6684.
    Résumé : Nanostructured functionalized silicas were used as a platform to compare the behaviour of anchored arylsulfanyl radicals depending on the nature of the precursor (diazene/thiol). The radicals generated from thiols exhibit higher half-lifetimes than the radicals generated from diazenes. The ability of thiols to maintain the sulfanyl radical density via degenerate hydrogen atom transfer is likely to account for this sharp difference.
    Mots-clés : chemistry, confinement, magic-angle, mesoporous silica, molecules, nmr, polarization, proton conductivity, pyrolysis, resonance.

  • Viger-Gravel, J.; Berruyer, P.; Gajan, D.; Basset, J. - M.; Lesage, A.; Tordo, P.; Ouari, O.; Emsley, L. Angewandte Chemie-International Edition 2017, 56 (30), 8726–8730.
    Résumé : Aqueous acrylamide gels can be used to provide dynamic nuclear polarization (DNP) NMR signal enhancements of around 200 at 9.4 T and 100 K. The enhancements are shown to increase with crosslinker concentration and low concentrations of the AMUPol biradical. This DNP matrix can be used in situations where conventional incipient wetness methods fail, such as to obtain DNP surface enhanced NMR spectra from inorganic nanoparticles. In particular, we obtain Cd-113 spectra from CdTe-COOH NPs in minutes. The spectra clearly indicate a highly disordered cadmium-rich surface.
    Mots-clés : acrylamide gels, angle-spinning nmr, correlation spectroscopy, dynamic nuclear polarization, high-frequency, nanoparticles, performance, polarizing agents, polyacrylamide gel, polymer gels, proteins, quantum dots, sensitivity, solid-state nmr.

  • Yang, X.; Huang, Q.; Bardelang, D.; Wang, C.; Lee, S. M. Y.; Wang, R. Organic & Biomolecular Chemistry 2017, 15 (38), 8046–8053.
    Résumé : Small-molecule kinase inhibitors (SMKIs) have been widely used in the treatment of a variety of cancers due to their clinically demonstrated efficacy. However, the use of some SMKIs, such as sorafenib (SO), has been plagued by their cardiotoxicity that has been frequently observed in treated patients. Herein we report that the encapsulation of SO by a synthetic receptor cucurbit[7]uril (CB[7]) alleviated the inherent cardiotoxicity of SO, as demonstrated in an in vivo zebrafish model. Moreover, the anti-cancer activity of SO was well preserved, upon its encapsulation by CB[7], as demonstrated by both in vitro and in vivo cancer/angiogenesis models. This discovery may provide new insights into a novel supramolecular formulation of SMKIs for the management of their side-effects.
    Mots-clés : angiogenesis, bioavailability, cancer, complexation, drug, encapsulation, Hepatotoxicity, sorafenib, synthetic receptor, zebrafish.

  • Yang, X.; Li, S.; Zhang, Q. - W.; Zheng, Y.; Bardelang, D.; Wang, L. - H.; Wang, R. Nanoscale 2017, 9 (30), 10606–10609.
    Résumé : Upon supramolecular encapsulation by using a synthetic nanocontainer (cucurbit[7]uril), the taste of the Guinness World's most bitter substance, denatonium benzoate, was dramatically concealed during a two-bottle preference drinking test in a mammalian model, demonstrating the significant potential of cucurbit[7]uril as a taste-masking nanocontainer for the first time.
    Mots-clés : drugs, encapsulation, forms, medicines, receptors.

  • Yin, H.; Chen, L.; Yang, B.; Bardelang, D.; Wang, C.; Lee, S. M. Y.; Wang, R. Organic & Biomolecular Chemistry 2017, 15 (20), 4336–4343.
    Résumé : Fasudil (FSD), a selective rho kinase (ROCK) inhibitor, was found to form 1 : 1 host-guest inclusion complexes with a synthetic macrocyclic receptor, cucurbit[7] uril(CB[7]), in aqueous solutions, as evidenced by H-1 NMR, photoluminescence and UV-visible spectroscopic titrations, isothermal titration calorimetry (ITC) titration, and electrospray ionization (ESI) mass spectrometry, as well as density functional theory (DFT) molecular modeling. Upon encapsulation, whereas the UV-vis absorbance of FSD experienced a moderate decrease and bathochromic shift, the fluorescence intensity of FSD at 354 nm was dramatically enhanced for up to 69-fold at neutral pH, which could potentially be applied in fluorescent tracking of the drug delivery and release. More interestingly, the binding affinity (K-a = (4.28 +/- 0.21) x 10(6) M-1), of FSD-CB[7] complexes under acidic conditions (pH = 2.0), is approximately three orders of magnitude higher than that (2.2 similar to 6.6 x 10(3) M-1) under neutral pH conditions (pH = 7.0). Accordingly, UV-visible spectroscopic titration of the free and complexed FSD under various pH conditions has demonstrated that the encapsulation of FSD by CB[7] shifted the pK(a) of the isoquinoline-N upward from 3.05 to 5.96 (Delta pK(a) of 2.91). The significantly higher binding affinity of the complexes under acidic conditions may be applied in developing the "enteric" formulation of FSD. Furthermore, our in vitro study of the bioactivity of FSD in the absence and presence of CB[7] on a neural cell line, SH-SY5Y, showed that the complexation preserved the drug's pro-neurite efficacy. Thus this discovery may lead to a fluorescence-trackable, orally administered enteric formulation of rho kinase inhibitors that are stable under gastric conditions, without compromising bioactivity of the drugs.
    Mots-clés : affinity, complexation, drug, encapsulation, fasudil, in-vivo, migration, stability, vitro, zebrafish models.

  • Yin, H.; Dumur, F.; Niu, Y.; Ayhan, M. M.; Grauby, O.; Liu, W.; Wang, C.; Siri, D.; Rosas, R.; Tonetto, A.; Gigmes, D.; Wang, R.; Bardelang, D.; Ouari, O. Acs Applied Materials & Interfaces 2017, 9 (38), 33220–33228.
    Résumé : This work describes latent fluorescence particles (LFPs) based on a new environmentally sensitive carbazole compound aggregated in water and their use as sensors for probing various cavitands and the different stages of aggregating systems. Cyclodextrins (CDs), cucurbit[n]urils (CB[n], n = 6, 7,'8), and a resorcinarene capsule were used to study the dynamic nature of the LFPs. The fluorescence was dramatically enhanced by a proposed disaggregation-induced emission enhancement (DIEE) mechanism with specific features for CB [n]. Then, the aggregated states of the dipeptides Leu-Leu, Phe-Phe, and Fmoc-Leu-Leu (vesicles, crystals, fibers) were studied by fluorescence spectroscopy and confocal fluorescence microscopy thanks to the adaptive and emissive behavior of the LFPs, allowing us to study an interesting polymorphism phenomenon. The LFPs have then been used in the sensing of the aggregation of the polysaccharide alginate, for which distinct fluorescence turn-on is detected upon stepwise biopolymer assembly, and for amylose detection. The carbazole particles not only adapt to various environments but also display multicolor fluorescent signals. They can be used for the fast probing of the aggregation propensity of newly prepared molecules or biologically relevant compounds or to accelerate the discovery of new macrocycles or of self-assembling peptides in water.
    Mots-clés : assemblies, binding, chameleonic dye, cucurbit[n]urils, disaggregation-induced emission enhancement, emission, fluorescent dyes, fluorophore, host-guest complexes, latent fluorescence particles, light, nanostructures, peptide aggregation, polysaccharide aggregation, quantum dots, water.

  • Zielonka, J.; Joseph, J.; Sikora, A.; Hardy, M.; Ouari, O.; Vasquez-Vivar, J.; Cheng, G.; Lopez, M.; Kalyanaraman, B. Chemical Reviews 2017, 117 (15), 10043–10120.
    Résumé : Mitochondria are recognized as one of the most important targets for new drug design in cancer, cardiovascular, and neurological diseases. Currently, the most effective way to deliver drugs specifically to mitochondria is by covalent linking a lipophilic cation such as an alkyltriphenylphosphonium moiety to a pharmacophore of interest. Other delocalized lipophilic cations, such as rhodamine, natural and synthetic mitochondria-targeting peptides, and nanoparticle vehicles, have, also been used for mitochondrial delivery of small molecules. Depending on the approach used, and the cell and mitochondrial membrane potentials, more than 1000-fold higher mitochondrial concentration can be achieved. Mitochondrial targeting has been developed to study mitochondrial physiology and dysfunction and the interaction between mitochondria and other subcellular organelles and for treatment of a variety of diseases such as neurodegeneration and cancer. In this Review, we discuss efforts to target small-molecule compounds to mitochondria for probing mitochondria function, as. diagnostic tools and potential therapeutics. We describe the physicochemical basis for mitochondrial accumulation of lipophilic cations, synthetic chemistry strategies to target compounds to mitochondria, mitochondrial probes, and sensors, and examples of mitochondrial targeting of bioactive compounds. Finally, we review published attempts to apply mitochondria-targeted agents for the treatment of cancer and neurodegenerative diseases.
    Mots-clés : aggregation-induced-emission, alpha-tocopheryl succinate, biomembrane-produced energy, cells-in-vitro, hydrogen-sulfide donor, ischemia-reperfusion injury, mass-spectrometry probe, pancreatic-cancer cells, positron-emission-tomography, ratiometric fluorescent-probe.