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Productions scientifiques

2019, ICR-2010-2019.

ACL - Articles dans des revues à comité de lecture

107 références.

  • Abdallah, M.; Al Mousawi, A.; Nechab, M.; Hijazi, A.; Fouassier, J. - P.; Dumur, F.; Lalevee, J. Chemphotochem 2019, 3 (11), 1162-1170.
    Résumé : Diethoxyacetate salts are investigated as new co-initiators for the free radical polymerization (FRP) of (meth)acrylates upon visible light exposure, with light emitting diodes (LEDs; 405 nm, 477 nm) being employed for this purpose. Interestingly, the impact of the counter cation on their initiating ability is clearly highlighted. When these co-initiators are combined with commercial photoinitiators such as 2-isopropylthioxanthone (ITX) or camphorquinone (CQ), good to excellent free radical polymerization initiating performances are found and high final reactive function conversions are achieved. In the absence of these co-initiators, no or poor polymerization occurs, clearly highlighting the importance of these co-initiators for an efficient process. These systems can be interesting for the replacement of aromatic amines opening the way for amine-free Type II photoinitiating systems.

  • Abdallah, M.; Bui, T. - T.; Goubard, F.; Theodosopoulo, D.; Dumur, F.; Hijazi, A.; Fouassier, J. - P.; Lalevee, J. Polymer Chemistry 2019, 10 (45), 6145-6156.
    Résumé : This study highlights the use of four new phenothiazine derivatives (denoted as B compounds: B106, B107, B108, and B111), which are synthesized and proposed as high performance visible light photoinitiators, in combination with an iodonium salt, in both the free radical polymerization (FRP) of acrylates and the cationic polymerization (CP) of epoxides upon visible light exposure using a cheap and safe Light Emitting Diode (LED) at 405 nm. Remarkably, two of them (B108 and B111) are also evaluated as photoredox catalysts (PCs). These phenothiazine compounds can also be used in three-component photoinitiating systems with an iodonium salt and an amine (e.g. N-phenylglycine (NPG)) for the FRP of acrylates upon irradiation with a LED@405 nm. They showed an outstanding polymerization photoinitiation ability; that is, excellent polymerization rates and high final reactive function conversions were obtained. The photoinitiation mechanisms were investigated through different techniques including RT-FTIR, UV-visible spectroscopy, fluorescence spectroscopy, cyclic voltammetry and electron paramagnetic resonance. A full picture of the involved photochemical mechanisms is provided. As high performance photoinitiators, phenothiazine-based systems are especially used in new radical photosensitive 3D printing resins to improve the depth of cure, ensuring the formation of very thick 3D printed polymers. Finally, the use of these new phenothiazine derivatives for the access to thick glass fiber composites using a near-UV conveyor (LED@395 nm) is outlined i.e. thick and filled samples again requiring improved depth of cure.

  • Abdallah, M.; Hijazi, A.; Graff, B.; Fouassier, J. - P.; Rodeghiero, G.; Gualandi, A.; Dumur, F.; Cozzi, P. G.; Lalevee, J. Polymer Chemistry 2019, 10 (7), 872-884.
    Résumé : The goal of this paper concerns the first evaluation of two recently reported coumarins to initiate photopolymerization reactions. These two compounds (CoumA and CoumB) are proposed as high performance visible light photoinitiators and evaluated as photoredox catalysts (PCs), in the presence of an iodonium salt or with an amine, for both the free radical polymerization (FRP) of (meth) acrylates and the cationic polymerization (CP) of epoxides upon visible light exposure using an LED at 405 nm. These coumarin derivatives showed a high photoinitiation ability i. e. excellent polymerization rates and high final monomer conversions were obtained. The photophysical and photochemical properties of the coumarin derivatives were studied in terms of absorption, steady state photolysis and fluorescence spectroscopy. The photoinitiation mechanisms of the coumarin derivatives were discussed from fluorescence quenching, redox behavior and cyclic voltammetry experiments. A full picture of the involved photochemical mechanisms is provided. Coumarin-based systems are high performance photoinitiators, and their use in new photosensitive 3D printing resins will also be presented. Remarkably, CoumB is also found to be very efficient for the preparation of hydrogels under mild conditions due to its high solubility in water i. e. CoumB corresponds to a high-performance water soluble photoinitiator. Finally, the usage of the new coumarin derivatives for photocomposite synthesis with glass fibers (thick samples with a good depth of cure) using a near-UV conveyor (LED @ 395 nm) is particularly outlined.

  • Abdallah, M.; Magaldi, D.; Hijazi, A.; Graff, B.; Dumur, F.; Fouassier, J. - P.; Bui, T. - T.; Goubard, F.; Lalevee, J. Journal of Polymer Science Part a-Polymer Chemistry 2019, 57 (20), 2081-2092.
    Résumé : In this article, new compounds based on the carbazole scaffold (DMs = DM1 and DM2, constituted by a carbazole unit connected on positions 3 and 6 to a two 4,4 '-dimethoxydiphenylamine groups and differing by the substituent present on the nitrogen heteroatom of the carbazole core) were synthesized and proposed as high-performance visible light photoinitiators/photosensitizers for both the free-radical polymerization of methacrylates and the cationic polymerization of epoxides upon visible light exposure using LED@405 nm. Remarkably, DM2 leads to higher final conversions than DM1. In order to study the photophysical and photochemical properties of the carbazole derivatives, different parameters were taken into account such as the light absorption, the steady-state photolysis, and the fluorescence spectroscopy. Using different techniques such as fluorescence quenching, redox behavior, and cyclic voltammetry, we are able to discuss the photosensitization/photoinitiation reactions providing a full coherent picture of the involved chemical mechanisms. The photosensitization of the carbazole derivatives occurred predominantly via singlet excited states at the rate of the diffusion limit. Upon exposure to laser diode at 405 nm, DMs show high performance in initiating systems for 3D resins. Remarkably, DM2 can also be used in photocomposite synthesis using light-emitting diode conveyor. (c) 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019

  • Amalian, J. - A.; Cavallo, G.; Al Ouahabi, A.; Lutz, J. - F.; Charles, L. Analytical Chemistry 2019, 91 (11), 7266-7272.
    Résumé : The defined sequence of two comonomers in sequence-controlled macromolecules can be used to store binary information which is further decoded by MS/MS sequencing. In order to achieve the full sequence coverage requested for reliable decoding, the structure of these polymers can be optimized to minimize their dissociation extent, as shown for poly(alkoxyamine phosphodiester)s (PAPs) where weak alkoxyamine bonds were introduced in each repeating unit to make all phosphate groups MS/MS silent. However, for secret communications, a too high MS/MS readability could be a drawback. In this context, the design of PAPs was further optimized in this work to also include a decrypting key based on slight variation of a fragment collision cross section. This was achieved by employing two different nitroxides to build the alkoxyamine moiety, each containing a coding alkyl segment of the same mass but different architectures. As a result, the digital sequence determined from primary fragments observed in MS/MS had to be decrypted according to appropriate rules that depend on the drift times measured by ion mobility spectrometry for repeating units released as secondary product ions.

  • Astolfi, P.; Clement, J. - L.; Gigmes, D.; Armeni, T.; Carloni, P.; Greci, L. Redox Report 2019, 24 (1), 56-61.
    Résumé : Objectives: Coenzyme Q(10), incorporated in DOPC lyposomes or naturally present in liver bovine mitochondria or in human blood plasma, was reacted with nitrogen dioxide (NO2)-N-center dot or with a (NO)-N-center dot/(NO2)-N-center dot mixture. Methods and Results: The reaction course was monitored by Electron Paramagnetic Resonance (EPR) spectroscopy and in all cases the formation of a di-tert-alkyl nitroxide was observed, deriving from the addition of (NO2)-N-center dot to one of the double bonds, most likely the terminal one, of the isoprenic chain. The rate constant for nitroxide formation was also determined by EPR spectroscopy and an initial rate of ca. 7 x 10(-8 )M s(-1) was obtained.

  • Audran, G.; Bagryanskaya, E.; Bagryanskaya, I.; Edeleva, M.; Joly, J. - P.; Marque, S. R. A.; Iurchenkova, A.; Kaletina, P.; Cherkasov, S.; Hai, T. T.; Tretyakov, E.; Zhivetyeva, S. Rsc Advances 2019, 9 (44), 25776-25789.
    Résumé : Because the C-ON bond homolysis rate constant k(d) is an essential parameter of alkoxyamine reactivity, it is especially important to tune k(d) without a major alteration of the structure of the molecule. Recently, several approaches have become known, e.g., protonation of functional groups and formation of metal complexes. In this paper, coordination reactions of [Zn(hfac)(2)(H2O)(2)] with a series of new SG1-based alkoxyamines affording complexes with different structures are presented. The k(d) values of the complexed forms of the alkoxyamines were compared to those of free and protonated ones to reveal the contribution of the electron-withdrawing property and structure stabilization. Together with previously published data, this work provides clues to the design of alkoxyamines that can be effectively activated upon coordination with metal ions. Furthermore, our results provide insight into the mechanism underlying the influence of complexation on the reactivity of alkoxyamines. This led us to describe different types of coordination: intramolecular in nitroxyl fragment, intramolecular in alkyl fragment, intramolecular between alkyl and nitroxyl fragment, and intermolecular one. All of them exhibit different trends which are dramatically altered by changes in conformation.

  • Audran, G.; Bosco, L.; Bremond, P.; Jugniot, N.; Marque, S. R. A.; Massot, P.; Mellet, P.; Koumba, T. M. M.; Parzy, E.; Rivot, A.; Thiaudiere, E.; Voisin, P.; Wedl, C.; Yamasaki, T. Organic Chemistry Frontiers 2019, 6 (21), 3663-3672.
    Résumé : Alkoxyamine 1 is selectively hydrolyzed by chymotrypsin and substilisin A into alkoxyamine 2H+ for which C-ON bond homolysis occurred with a 4-fold increase in rate constants compared to 1 while non-specific proteases had no effect. This highlights the triggering effect of enzymes. This is a proof of concept for a theranostic approach for treating solid tumors using enzyme-activated alkoxyamines releasing a cytotoxic alkyl radical and a stable nitroxide as a contrast agent for Overhauser-enhanced MRI.

  • Audran, G.; Jacoutot, S.; Jugniot, N.; Marque, S. R. A.; Mellet, P. Analytical Chemistry 2019, 91 (9), 5504-5507.
    Résumé : While optical methods are not efficient enough for the easy, fast, and efficient detection of enzymatic activity in turbid media, the properties of the electron paramagnetic resonance (EPR) technique make it suitable for use in such media. Nitroxides which exhibit a change in their EPR hyperfine coupling constants upon enzymatic activity and are selective to lipases were developed under the name of shiftingnitroxides. Several fatty acids, exhibiting saturated and unsaturated chains of various lengths, were coupled with the shifting-nitroxide via an enol ester link and tested against several lipases. As the solubility of fatty acids is low in HEPES buffer, experiments were performed in turbid aqueous solution. Almost all labeled fatty acids were hydrolyzed by Candida rugosa lipase, and more selectivity is observed with Porcine Pancreas lipase type II. No activity was observed for lipase AK Amano 20, Candida antartica lipase B, and Mucor miehei lipase.

  • Audran, G.; Marque, S. R. A.; Santelli, M. Journal of Physical Chemistry A 2019, 123 (7), 1380-1388.
    Résumé : After quantum calculations of absolute free energies of polyatomic sulfur derivatives or hydrocarbon oligomer compounds, we have studied the variations of G(n) as a function of the number of repeating units n (sulfur atoms or hydrocarbon units, G(n) = 2 to about 60), and observed that these values can be correlated by (a) a nearly perfect linear relationship, Gn = An + B (A and B, constants), with a high accuracy which enables an extrapolation for higher values of n, and (b) a power law:, delta G = G(n)/n - G((n-1)) /(n-1) = C/n(d) (C and d, constants). From comparison of variations of the C-C bond lengths, we show that the conjugation of trans-polyenes (up to C60H62) is more important than for polyynes (up to C60H2).

  • Aupic, C.; Mohamed, A. A.; Figliola, C.; Nava, P.; Tuccio, B.; Chouraqui, G.; Parrain, J. - L.; Chuzel, O. Chemical Science 2019, 10 (26), 6524-6530.
    Résumé : Stereogenic main group elements are clearly generating interest in the enantioselective catalysis field. Surprisingly, while chiral organoboron reagents are very useful in stereoselective transformations, few scaffolds stereogenic at boron and configurationally stable have been reported to date. Herein, we describe an original library of chiral NHC-boranes, stereogenic at the boron atom, that has been prepared in only a few steps and in good yields (up to 93%). Key steps involve a chlorination/arylation sequence in the presence of simple Grignard reagents from bicyclic NHC-boranes. The high and unprecedented diastereoselectivity observed during the second step (up to 99 : 1 dr) has been rationalized through a plausible S(RN)1 mechanism thanks to EPR observations and DFT calculations.

  • Bahramian, A.; Eyraud, M.; Maria, S.; Vacandio, F.; Djenizian, T.; Knauth, P. Corrosion Science 2019, 149, 75-86.
    Résumé : Cu/Ni-P/Au multi-layer systems are employed as electrical contacts. The Au top-layer is thin and porous. These pores deliver the corrosive media to the under-layer, which induces the corrosion by a galvanic coupling mechanism. Therefore, filling these pores is essential to improve the lifetime of electronic devices. The pores can be sealed by the electrodeposition of poly(methyl methacrylate) that decreased the porosity index (about 97%) and increased the corrosion resistance (about

  • Bai, S.; Barbatti, M. Journal of chemical theory and computation 2019, 15 (3), 1503-1513.
    Résumé : Spin-exchange internal conversion (SEIC) is a general class of reactions having singlet fission and triplet fusion as particular cases. Based on a charge transfer (CT) mediated mechanism and analytical derivation with a model Hamiltonian, we propose proxies for estimating the coupling strength in both diabatic and adiabatic pictures for general SEIC reactions. In the diabatic picture, we demonstrated the existence of a bilinear relationship between the coupling strength and molecular orbital overlap, which provides a practical way to predict diabatic couplings. In the adiabatic picture, we showed that nonadiabatic couplings can be approximated by simple functions of the wave function

  • Bailey, D. M.; Brugniaux, J. V.; Filipponi, T.; Marley, C. J.; Stacey, B.; Soria, R.; Rimoldi, S. F.; Cerny, D.; Rexhaj, E.; Pratali, L.; Salinas Salmon, C.; Murillo Jauregui, C.; Villena, M.; Smirl, J. D.; Ogoh, S.; Pietri, S.; Scherrer, U.; Sartori, C. Journal of Physiology-London 2019, 597 (2), 611-629.
    Résumé : Chronic mountain sickness (CMS) is a maladaptation syndrome encountered at high altitude (HA) characterised by severe hypoxaemia that carries a higher risk of stroke and migraine and is associated with increased morbidity and mortality. The present cross-sectional study examined to what extent exaggerated systemic oxidative-inflammatory-nitrosative stress (OXINOS), defined by an increase in free radical formation and corresponding decrease in vascular nitric oxide (NO) bioavailability, is associated with impaired cerebrovascular function, accelerated cognitive decline and depression in CMS. Venous blood was obtained from healthy male lowlanders (80 m, n = 17), and age- and gender- matched HA dwellers born and bred in La Paz, Bolivia (3600 m) with (CMS+, n= 23) and without (CMS-, n= 14) CMS. We sampled blood for oxidative (electron paramagnetic resonance spectroscopy, HPLC), nitrosative (ozone-based chemiluminescence) and inflammatory (fluorescence) biomarkers. We employed transcranial Doppler ultrasound to measure cerebral blood flow (CBF) and reactivity. We utilised psychometric tests and validated questionnaires to assess cognition and depression. Highlanders exhibited elevated systemic OXINOS (P< 0.05vs. lowlanders) that was especially exaggerated in the more hypoxaemic CMS+ patients (P< 0.05 vs. CMS-). OXINOS was associated with blunted cerebral perfusion and vasoreactivity to hypercapnia, impaired cognition and, in CMS+, symptoms of depression. Collectively, these findings are the first to suggest that a physiological continuum exists for hypoxaemia-induced OXINOS in HA dwellers that when excessive is associated with accelerated cognitive decline and depression, helping identify those in need of specialist neurological assessment and support.

  • Bakhta, S.; Kabri, Y.; Crozet, M. D.; Nedjar-Kolli, B.; Vanelle, P. Synthetic Communications 2019, 49 (19), 2561-2571.
    Résumé : A series of imidazo[1,2-a]pyridinylpropenenitriles were synthesized via consecutive one-pot Suzuki-Miyaura and Knoevenagel reactions in water/ethanol mixture between imidazo[1,2-a]pyridine-2-carbaldehydes, arylboronic acids and malononitrile, methyl cyanoacetate or ethyl cyanoacetate. This environmental friendly procedure tolerates a wide range of boronic acids and affords a new substituted imidazo[1,2-a]pyridinyl propenenitriles in good yields under microwave irradiation. [GRAPHICS] .

  • Barbosa, N. M. de A.; Zemmouche, M.; Gosset, P.; Garcia-Iriepa, C.; Ledentu, V.; Navizet, I.; Didier, P.; Ferre, N. Chemphotochem 2019.
    Résumé : The photophysical properties of oxyluciferin, the light emitter responsible for firefly bioluminescence, are pH-dependent. One of the potential proton acceptor/donor is adenosine monophosphate (AMP). We have studied three oxyluciferin synthetic analogues with or without AMP, in water, in the pH=5 to 11 range, using both experimental steady-state absorption spectroscopy or the recently developed computational protocol that uses constant pH molecular dynamics and then hybrid QM/MM calculations (CpHMD-then-QM/MM). The latter features a systematic investigation of all the protonation microstates using molecular dynamics simulations coupled to thousands hybrid QM/MM vertical excitation energies. Our results demonstrate that AMP does not significantly modify the visible light absorption of the analogues, whatever the pH value. We also show that CpHMD-then-QM/MM is capable to qualitatively reproduce the pH-dependent absorption spectrum of the analogues, despite the employed low QM level of theory.

  • Baron, M.; Rakotorinina, M. - D.; El Assil, M. I.; Guillaneuf, Y.; Gigmes, D.; Siri, D.; Gaudel-Siri, A.; Flat, J. - J.; Quinebeche, S.; Cassagnau, P.; Beyou, E. Materials Today Communications 2019, 19, 271-276.
    Résumé : For the first time, the melt radical grafting of diethylmaleate (DEM) and maleic anhydride (MA) onto oligoamide-11 (OA11) and polyamide-11 (PA11) was performed in presence of new acyloxyimide derivatives in the temperature range 190 degrees C-250 degrees C in an autoclave and a mini-extruder, respectively. The DEM grafting degree was studied as a function of reaction temperature, the DEM concentration, the acyloxyimide concentration and its chemical structure. The degree of grafting of DEM was determined by H-1 NMR and we obtained a DES (diethylsuccinimate) functionalization degree (FD) as high as 9 mol% onto OA11 when using tBu-NAPI as Habstractor at 230 degrees C. However, the transposition of this grafting reaction at a pilot scale did not permit to obtain such a high DES FD while the morphological study of PA11/EVOH blends with the grafted copolymer did not significantly improve the adhesion between the two phases.

  • Barthelemy, A. - L.; Tuccio, B.; Magnier, E.; Dagousset, G. Synlett 2019, 30 (13), 1489-1495.
    Résumé : Alkoxyl radicals are highly reactive species which rapidly react by hydrogen atom transfer (HAT) or beta-fragmentation to afford a carbon-centered radical. We discuss herein how these RO center dot radicals can be efficiently trapped in an intermolecular manner by styrene derivatives when they are generated by photoredox catalysis from the corresponding N-alkoxypyridinium salts. This allows for the synthesis of valuable ethers with complete anti-Markovnikov regioselectivity.

  • Besson, E.; Gastaldi, S.; Bloch, E.; Zielonka, J.; Zielonka, M.; Kalyanaraman, B.; Aslan, S.; Karoui, H.; Rockenbauer, A.; Ouari, O.; Hardy, M. Analyst 2019, 144 (14), 4194-4203.
    Résumé : The generation of superoxide radical anion in biological systems is one of the major initiating events in the redox biology of NADPH oxidases and mitochondrial redox signalling. However, the pallette of chemical tools for superoxide detection is very limited, hampering progress in understanding the chemical biology of superoxide. Although EPR spin trapping is regarded as the most rigorous technique for superoxide detection, rapid reduction of the EPR-active superoxide spin adducts to EPR-silent hydroxylamines, or to hydroxyl radical adducts by bioreductants, significantly limits the applicability of this technique in biological systems. To overcome these limitations, in this work, we report the synthesis and characterization of a new mesoporous silica functionalized with a phosphorylated cyclic spin trap (DIPPMPO nitrone). The DIPPMPO-grafted silica is a versatile spin-trap agent enabling the identification of a wide range of carbon or oxygen-centered transient radicals in organic and in aqueous media. Moreover, superoxide was efficiently trapped under in vitro conditions in both cell-free and cellular systems. The generated superoxide adduct exhibited an exceptional half-life of 3.5 h and a resistance toward bioreductant agents such as glutathione for several hours.

  • Bisht, A. S.; Hoang-Thi, K.; Ledoux-Rak, I.; Remita, H.; Dumur, F.; Guerlin, A.; Dumas, E.; Mayer, C. R. Inorganics 2019, 7 (5), 64.
    Résumé : A significant enhancement of the second harmonic generation (SHG) from second-order nonlinear optical (NLO) dyes in solution has been evidenced when these dyes were grafted onto the surface of spherical gold nanoparticles (AuNPs), as compared to their NLO response without AuNPs. The length, as well as the nature of the spacers between the gold particle and the chromophore, is shown to play an important role, a benzene linker being more favorable to AuNP-4-dimethylamino-N-methyl-4-stilbazolium tosylate (DAST) interactions, as illustrated by a higher exaltation of the NLO response for DAST molecules linked to AuNP via a phenyl ring as compared to their equivalent with a CH2-CH2 link.

  • Bonardi, A. H.; Bonardi, F.; Dumur, F.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Macromolecular Rapid Communications 2019, 1900495.
    Résumé : Photo-induced thermal polymerization upon near-infrared (NIR) light irradiation has been reported in the literature. In this approach, a component able to convert the NIR light into heat must be used in combination with a thermal initiator to initiate the free-radical polymerization of (meth)acrylates. In recent studies, some absorbers have been presented as very efficient heat generators (called heaters). In the present work, different fillers are investigated as heaters and compared to organic NIR absorbers. An alkoxyamine (e.g., BlocBuilder-MA) is used as thermal initiator and is dissociated by the heat generated by the NIR photoexcitation of the fillers. In the present work, several fillers are examined: graphene oxide, graphene nanoplatelets, multi-walled carbon nanotubes, and silicon carbide. Due to the energy of the photon delivered, NIR light curing is challenging but offers several advantages compared to visible light. The most interesting feature is the deeper penetration of the light inside the photocurable resin, enabling the polymerization of thick samples. Parallel to this, incorporation of fillers in resins allows unique access to composites through photothermal polymerization of (meth)acrylates. Three different wavelengths of irradiation have been studied: 785, 940, and 1064 nm.

  • Bonardi, A.; Bonardi, F.; Noirbent, G.; Dumur, F.; Dietlin, C.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Polymer Chemistry 2019, 10 (47), 6505-6514.
    Résumé : In this article, near-infrared dyes of different structures have been investigated as new photoinitiators/photosensitizers for the free radical polymerization (FRP) of methacrylates upon Near InfraRed (NIR) light exposure using a laser diode @785 nm, @940 nm and @1064 nm. Interestingly, the use of squaraine, squarylium, boron-pyrromethene and porphyrin derivatives as efficient photoinitiators is clearly highlighted. These dyes are used in combination with an iodonium salt and a phosphine. Additionally, a thermal initiator can be added to the resin to take advantage of the photothermal effect, i.e., to the heat release during the polymerization process, so that polymerization kinetics could be greatly improved compared to the pure photochemical mode. These dyes can be proposed as alternatives to the well-established cyanine dyes, more commonly used for the photopolymerization of (meth)acrylates under NIR light.

  • Bonardi, A. - H.; Zahouily, S.; Dietlin, C.; Graff, B.; Morlet-Savary, F.; Ibrahim-Ouali, M.; Gigmes, D.; Hoffmann, N.; Dumur, F.; Lalevee, J. Catalysts 2019, 9 (8), 637.
    Résumé : Photopolymerization processes, and especially those carried out under visible light, are more and more widespread for their multiple advantages compared to thermal processes. In the present paper, new 1,8-naphthalimide derivatives are proposed as photoinitiators for free-radical polymerization upon visible light exposure using light-emitting diodes (LEDs) at 395, 405, and 470 nm. These photoinitiators are used in combination with both iodonium salts and phosphine. The synthesis of these compounds as well as their excellent polymerization initiation ability for methacrylate monomers are presented in this article. A full picture of the involved chemical mechanisms is also provided thanks to photolysis, radical characterization, and redox measurements.

  • Bonnevide, M.; Jimenez, A. M.; Dhara, D.; Phan, T. N. T.; Malicki, N.; Abbas, Z. M.; Benicewicz, B.; Kumar, S. K.; Couty, M.; Gigmes, D.; Jestin, J. Macromolecules 2019, 52 (20), 7638-7645.
    Résumé : We control nanoparticle (NP) dispersion by leveraging the entropic and enthalpic effects associated with mixing silica NPs grafted with polyisoprene (PI) chains into matrices of varying degrees of chemical dissimilarity. Previous work in this area has primarily focused on entropic factors alone, and hence, this work represents a significant advance over the current state-of-the-art. We show using a combination of transmission electron microscopy/small- angle X-ray scattering that mixing grafted particles with PI matrices of identical microstructure yields dispersion states as found in the literature for such entropic systems. However, replacing the PI matrix chains with dissimilar matrices leads to an introduction of enthalpic interactions that, in some cases, can drastically change the resulting morphology. In particular, while slightly different PI microstructures for the grafted and free chains only yield moderated differences, using styrene-butadiene copolymers as a matrix leads to a completely different behavior. In the last case, phase separation becomes more likely with the increasing graft length, while the PI system (whose behavior is dominated by entropic factors) shows the opposite behavior. Tuning the relative importance of enthalpic versus entropic factors is thus another tool in controlling the self-assembled structure of NPs, which gives rise to enhanced macroscopic properties in the composite.

  • Bonucci, A.; Ouari, O.; Guigliarelli, B.; Belle, V.; Mileo, E. Chembiochem 2019.
    Résumé : Exploring the structure and dynamics of biomolecules in the context of their intracellular environment has become the ultimate challenge for structural biology. As the cellular environment is barely reproducible in vitro, investigation of biomolecules directly inside cells has attracted a growing interest. Among magnetic resonance approaches, site-directed spin labeling (SDSL) coupled to electron paramagnetic resonance (EPR) spectroscopy provides competitive and advantageous features to capture protein structure and dynamics inside cells. To date, several in-cell EPR approaches have been successfully applied to both bacterial and eukaryotic cells. In this review, the major advances of in-cell EPR spectroscopy are summarized, as well as the challenges this approach still poses.

  • Brunel, D.; Noirbent, G.; Dumur, F. Dyes and Pigments 2019, 170, UNSP 107611.
    Résumé : Ferrocene is an exceptional building block for the development of dyes with reversible redox properties. Dyes absorbing int the near infrared and infrared region are actively researched due to their potential applications ranging from telecommunication to defence systems. In this review, an overview of the different NIR and infrared dyes reported to date is presented. Parallel to the photophysical characteristics, the synthetic pathways giving access to these structures is presented.

  • Bruno, R.; Maresca, M.; Canaan, S.; Cavalier, J. - F.; Mabrouk, K.; Boidin-Wichlacz, C.; Olleik, H.; Zeppilli, D.; Brodin, P.; Massol, F.; Jollivet, D.; Jung, S.; Tasiemski, A. Marine Drugs 2019, 17 (9), 512.
    Résumé : Antimicrobial peptides (AMPs) are natural antibiotics produced by all living organisms. In metazoans, they act as host defense factors by eliminating microbial pathogens. But they also help to select the colonizing bacterial symbionts while coping with specific environmental challenges. Although many AMPs share common structural characteristics, for example having an overall size between 10-100 amino acids, a net positive charge, a gamma-core motif, or a high content of cysteines, they greatly differ in coding sequences as a consequence of multiple parallel evolution in the face of pathogens. The majority of AMPs is specific of certain taxa or even typifying species. This is especially the case of annelids (ringed worms). Even in regions with extreme environmental conditions (polar, hydrothermal, abyssal, polluted, etc.), worms have colonized all habitats on Earth and dominated in biomass most of them while co-occurring with a large number and variety of bacteria. This review surveys the different structures and functions of AMPs that have been so far encountered in annelids and nematodes. It highlights the wide diversity of AMP primary structures and their originality that presumably mimics the highly diverse life styles and ecology of worms. From the unique system that represents marine annelids, we have studied the effect of abiotic pressures on the selection of AMPs and demonstrated the promising sources of antibiotics that they could constitute.

  • Capozzi, A.; Patel, S.; Gunnarsson, C. P.; Marco-Rius, I.; Comment, A.; Karlsson, M.; Lerche, M. H.; Ouari, O.; Ardenkjaer-Larsen, J. H. Angewandte Chemie-International Edition 2019, 58 (5), 1334-1339.
    Résumé : Free radicals generated by UV-light irradiation of a frozen solution containing a fraction of pyruvic acid (PA) have demonstrated their dissolution dynamic nuclear polarization (dDNP) potential, providing up to 30% [1-C-13] PA liquid-state polarization. Moreover, their labile nature has proven to pave a way to nuclear polarization storage and transport. Herein, differently from the case of PA, the issue of providing dDNP UV-radical precursors (trimethylpyruvic acid and its methyl-deuterated form) not involved in any metabolic pathway was investigated. The C-13 dDNP performance was evaluated for hyperpolarization of [U-C-13(6),1,2,3,4,5,6,6-d(7)]-D-glucose. The generated UV-radicals proved to be versatile and highly efficient polarizing agents, providing, after dissolution and transfer (10 s), a C-13 liquid-state polarization of up to 32%.

  • Carvalho, V. N. D.; Hertanu, A.; Grelard, A.; Mchinda, S.; Soustelle, L.; Loquet, A.; Dufourc, E. J.; Varma, G.; Alsop, D. C.; Thureau, P.; Girard, O. M.; Duhamel, G. Journal of magnetic resonance (San Diego, Calif. : 1997) 2019, 311, 106668-106668.
    Résumé : T1D, the relaxation time of dipolar order, is sensitive to slow motional processes. Thus T1D is a probe for membrane dynamics and organization that could be used to characterize myelin, the lipid-rich membrane of axonal fibers. A mono-component T1D model associated with a modified ihMT sequence was previously proposed for in vivo evaluation of T1D with MRI. However, experiments have suggested that myelinated tissues exhibit multiple T1D components probably due to a heterogeneous molecular mobility. A bi-component T1D model is proposed and implemented. ihMT images of ex-vivo, fixed rat spinal cord were acquired with multiple frequency alternation rate. Fits to data yielded two T1Ds of about 500mus and 10ms. The proposed model seems to further explore the complexity of myelin organization compared to the previously reported mono-component T1D model.

  • Charles, L.; Chendo, C.; Poyer, S. Rapid communications in mass spectrometry : RCM 2019.
    Résumé : This review covers applications of ion mobility spectrometry (IMS) hyphenated to mass spectrometry (MS) in the field of synthetic polymers.

  • Cheng, G.; Zhang, Q.; Pan, J.; Lee, Y.; Ouari, O.; Hardy, M.; Zielonka, M.; Myers, C. R.; Zielonka, J.; Weh, K.; Chang, A. C.; Chen, G.; Kresty, L.; Kalyanaraman, B.; You, M. Nature Communications 2019, 10, 2205.
    Résumé : Lung cancer often has a poor prognosis, with brain metastases a major reason for mortality. We modified lonidamine (LND), an antiglycolytic drug with limited efficacy, to mitochondria targeted mito-lonidamine (Mito-LND) which is 100-fold more potent. Mito-LND, a tumor selective inhibitor of oxidative phosphorylation, inhibits mitochondrial bioenergetics in lung cancer cells and mitigates lung cancer cell viability, growth, progression, and metastasis of lung cancer xenografts in mice. Mito-LND blocks lung tumor development and brain metastasis by inhibiting mitochondrial bioenergetics, stimulating the formation of reactive oxygen species, oxidizing mitochondrial peroxiredoxin, inactivating AKT/mTOR/p70S6K signaling, and inducing autophagic cell death in lung cancer cells. Mito-LND causes no toxicity in mice even when administered for eight weeks at 50 times the effective cancer inhibitory dose. Collectively, these findings show that mitochondrial targeting of LND is a promising therapeutic approach for investigating the role of autophagy in mitigating lung cancer development and brain metastasis.

  • Cheng, G.; Zielonka, J.; Hardy, M.; Ouari, O.; Chitambar, C. R.; Dwinell, M. B.; Kalyanaraman, B. Oncotarget 2019, 10 (37), 3518-3532.
    Résumé : We demonstrate that combined treatment with metformin (Met) or its mitochondria-targeted analog, mito-metformin (Mito-Met), and various iron chelators synergistically inhibits proliferation of pancreatic and triple-negative breast cancer cells. Previously, we reported that Met (at millimolar levels) and Mito-Met (at micromolar levels) inhibited pancreatic cancer cell proliferation. Inhibition of mitochondrial complex I and mitochondrial oxidative phosphorylation (OXPHOS) through stimulation of mitochondrial redox signaling was proposed as a key mechanism for decreased cancer cell proliferation. Because of its poor bioavailability, the use of Met as a "stand-alone" antitumor drug has been questioned. Iron chelators such as deferasirox (DFX) and dexrazoxane (DXR) exhibit antiproliferative effects in cancer cells. The potency of Met and Mito-Met was synergistically enhanced in the presence of iron chelators, DFX, N,N'-bis(2-hydroxyphenyl)ethylendiamine-N,N'-diacetic acid (HBED), and deferoxamine (DFO). Met, DXR (also ICRF-187), and DFO are FDA-approved drugs for treating diabetes, decreasing the incidence and severity of cardiotoxicity following chemotherapy, and mitigating iron toxicity, respectively. Thus, the synergistic antiproliferative effects of Met and Met analogs and iron chelators may have significant clinical relevance in cancer treatment. These findings may have implications in other OXPHOS-mediated cancer therapies.

  • Combes, S.; Tran, K. T.; Ayhan, M. M.; Karoui, H.; Rockenbauer, A.; Tonetto, A.; Monnier, V.; Charles, L.; Rosas, R.; Viel, S.; Siri, D.; Tordo, P.; Clair, S.; Wang, R.; Bardelang, D.; Ouari, O. Journal of the American Chemical Society 2019.
    Résumé : Triangular shapes have inspired scientists over time and are common in nature, such as the flower petals of oxalis triangularis, the triangular faces of tetrahedrite crystals, and the icosahedron faces of virus capsids. Supramolecular chemistry has enabled the construction of triangular assemblies, many of which possess functional features. Among these structures, cucurbiturils have been used to build supramolecular triangles, and we recently reported paramagnetic cucurbit[8]uril (CB[8]) triangles, but the reasons for their formation remain unclear. Several parameters have now been identified to explain their formation. At first sight, the radical nature of the guest was of prime importance in obtaining the triangles, and we focused on extending this concept to biradicals to get supramolecular hexaradicals. Two sodium ions were systematically observed by ESI-MS in trimer structures, and the presence of Na+ triggered or strengthened the triangulation of CB[8]/guest 1:1 complexes in solution. X-ray crystallography and molecular modeling have allowed the proposal of two plausible sites of residence for the two sodium cations. We then found that a diamagnetic guest with an H-bond acceptor function is equally good at forming CB[8] triangles. Hence, a guest molecule containing a ketone function has been precisely triangulated thanks to CB[8] and sodium cations as determined by DOSY-NMR and DLS. A binding constant for the triangulation of 1:1 to 3:3 complexes is proposed. This concept has finally been extended to the triangulation of ditopic guests toward network formation by the reticulation of CB[8] triangles using dinitroxide biradicals.

  • Corinti, D.; Maccelli, A.; Crestoni, M. E.; Cesa, S.; Quaglio, D.; Botta, B.; Ingallina, C.; Mannina, L.; Tintaru, A.; Chiavarino, B.; Fornarini, S. International Journal of Mass Spectrometry 2019, 444, UNSP 116179.
    Résumé : Anthocyanins are widespread in plants and flowers, being responsible for their different colouring. Two representative members of this family have been selected, cyanidin 3-O-beta-glucopyranoside and 3-O-beta-galactopyranoside, and probed by mass spectrometry based methods, testing their performance in discriminating between the two epimers. The native anthocyanins, delivered into the gas phase by electrospray ionization, display a comparable drift time in ion mobility mass spectrometry (IM-MS) and a common fragment, corresponding to loss of the sugar moiety, in their collision induced dissociation (CID) pattern. However, the IR multiple photon dissociation (IRMPD) spectra in the fingerprint range show a feature particularly evident in the case of the glucoside. This signature is used to identify the presence of cyanidin 3-O-beta-glucopyranoside in a natural extract of pomegranate. In an effort to increase any differentiation between the two epimers, aluminum complexes were prepared and sampled for elemental composition by FT-ICR-MS. CID experiments now display an extensive fragmentation pattern, showing few product ions peculiar to each species. More noteworthy is the IRMPD behavior in the OH stretching range showing significant differences in the spectra of the two epimers. DFT calculations allow to interpret the observed distinct bands due to a varied network of hydrogen bonding and relative conformer stability. (C) 2019 The Authors. Published by Elsevier B.V.

  • Curti, C.; Souab, K. H.; Lamy, E.; Mathias, F.; Bornet, C.; Guinard, B.; Fersing, C.; Primas, N.; Albanese, J.; Vanelle, P. Pharmazie 2019, 74 (6), 357-362.
    Résumé : In intensive care, beta-lactams can be reconstituted in 50 mL polypropylene syringes with NaCl 0.9 % and administered for 8 to 12 h at various concentrations with motor-operated syringe pumps. The feasibility and/or the stability of these antibiotic therapies are often poorly known by clinicians. The purpose of this study was to determine the stability of seven antipyocyanic beta-lactam antibiotics and cilastatin under real-life conditions. Stability indicating HPLC methods allowing quantification in pharmaceutical preparations and subsequent stability studies were performed. The stability studies showed that continuous infusion of piperacillin/tazobactam 80/10 mg/mL, of cefepime

  • Deletraz, A.; Zeamari, K.; Di Meo, F.; Fabre, P. - L.; Reybier, K.; Trouillas, P.; Tuccio, B.; Durand, G. New Journal of Chemistry 2019, 43 (39), 15754-15762.
    Résumé : In this work, alpha-phenyl-N-tert-butylnitrone (PBN), N-benzylidene-1-diethoxyphosphoryl-1-methylethylamine N-oxide (PPN) and N-benzylidene-1-ethoxycarbonyl-1-methylethylamine N-oxide (EPPN) derivatives bearing methoxy groups (MeO-) on the phenyl ring were synthesized. Their electrochemical properties were studied by cyclic voltammetry and the results showed that the position and the number of methoxy substituents influence the redox potential of the nitronyl group. The spin-trapping ability of the derivatives was next investigated by electron paramagnetic resonance spectroscopy for the hydroxymethyl radical (CH2OH). The ortho, meta and para mono-substituted-PBN derivatives exhibited similar trapping rates to the parent PBN while surprisingly, nitrones with two MeO-substituents on the ortho-position failed to trap CH2OH. The trapping rates of the parent compounds were ranked as follows: PPN > EPPN > PBN, indicating that the presence of diethoxyphosphoryl and ethoxycarbonyl electron withdrawing groups on the N-tert-butyl group significantly enhanced the reactivity towards hydroxymethyl radicals. The effect of the substitutions on the atomic partial charges of the nitronyl-moiety and on the ionization potential was computationally rationalized and showed a strong correlation between the ionization potential and the experimentally measured oxidation potential.
  • Delmotte, N.; Roche, M.; Giraud, R.; Roche, M.; Falaise, C.; Chambost, H.; Gensollen, S. Haemophilia 2019, 25, 102-102.

  • Djeridi, W.; Ben Mansour, N.; Ouederni, A.; Llewellyn, P. L.; El Mir, L. Solid State Sciences 2019, 93, 37-43.
    Résumé : Nanoporous carbon was synthesized by blending formaldehyde and pyrogallol in water. In this process picric acid was used as a catalyst and nickel oxide nanoparticles as an incorporated element. The samples were prepared at different pyrolysis temperatures. The impact of the elaboration conditions on the surface properties and methane and carbon dioxide (CH4, CO2) adsorption at room temperature and high pressure up to 25 bars have been investigated. The obtained nanocomposites were characterized by different techniques such as: adsorption-desorption of N-2 at 77 K, X-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The characterization of the samples revealed that the volumes of methane and carbon dioxide adsorbed are not related only to the specific surface area. The samples incorporated with nickel oxide and pyrolysed at less than 650 degrees C have improved the adsorbed amount of CO2 and CH4, but for pyrolysis temperature higher than 650 degrees C we note that the adsorbed amount decreases due to the formation of carbon nanotubes surrounding the nickel nanoparticles which prevents gas to be highly adsorbed. The obtained material is promising for advanced technological applications for selective gas storage.

  • Dol, C.; Gerbaud, G.; Guigliarelli, B.; Bloch, E.; Gastaldi, S.; Besson, E. Physical Chemistry Chemical Physics 2019, 21 (29), 16337-16344.
    Résumé : The development of new open shell systems is essential for advances in spin science. In this work, we report the synthesis and characterization of three nanostructured materials, namely SBA-15 silicas, periodic mesoporous organosilicas (PMOs) and lamellar polysilsesquioxanes, all functionalized with the same diazene-based phenoxyl radical precursor. The impact of the nature of the material, i.e. loading of radical precursor and structure, on half-lifetimes (t(1/2)) and relaxation times of phenoxyl radicals was investigated. Although phenoxyl radicals are transient in solution, their t(1/2) range from hours to years at room temperature (RT) when they are embedded in nanostructured materials. The above mentioned functionalized materials were used to generate the corresponding phenoxyl radicals and their relaxation times were measured (T-1e and T-m) from 50 K to RT. The results were rationalized in terms of limited mobility of the radical as a result of supramolecular interactions and structure rigidity. All these data show that it is possible to design functionalized nanostructured material with radicals possessing specific electronic relaxation properties which can be of interest in fields like DNP, organic magnetism or spin qubit.

  • Dorey, S.; Gaston, F.; Girard-Perier, N.; Dupuy, N.; Marque, S. R. A.; Delaunay, L. Industrial & Engineering Chemistry Research 2019, 58 (31), 14115-14123.
    Résumé : Polymers such as polyethylene (PE) and ethylene vinyl alcohol (EVOH) are primary constituents of multilayer films used in the food and biopharmaceutical packaging. In order to explore the film behavior after gamma-sterilization, several tests are performed (tensile tests, differential scanning calorimetry (DSC), oxygen transmission rate (OTR) and water vapor transmission rate (WVTR). The investigation of the PE/EVOH/PE multilayer film is done at several gamma-irradiation doses up to 270 kGy. For irradiation dose up to SO kGy, mechanical properties are not altered. Whatever the irradiation dose, water barrier in PE/EVOH/PE multilayer film is not altered whereas the oxygen barrier property is increased by 300%. This enhancement is shown not to occur due to reorientation, closer chain packaging and restriction of chain mobility of polymer chains in the amorphous phase of the different polymers. This enhancement rather comes from a change of the chemical environment of the EVOH layer.

  • Dumur, F. Catalysts 2019, 9 (9), 736.
    Résumé : In recent years, polymerization processes activated by light have attracted a great deal of interest due to the wide range of applications in which this polymerization technique is involved. Parallel to the traditional industrial applications ranging from inks, adhesives, and coatings, the development of high-tech applications such as nanotechnology and 3D-printing have given a revival of interest to this polymerization technique known for decades. To initiate a photochemical polymerization, the key element is the molecule capable to interact with light, i.e., the photoinitiator and more generally the photoinitiating system, as a combination of several components is often required to create the reactive species responsible for the polymerization process. With the aim of reducing the photoinitiator content while optimizing the polymerization yield and/or the polymerization speed, photocatalytic systems have been developed, enabling the photosensitizer to be regenerated during the polymerization process. In this review, an overview of the photocatalytic systems developed for polymerizations carried out under a low light intensity and visible light is provided. Over the years, a wide range of organometallic photocatalysts has been proposed, addressing both the polymerization efficiency and/or the toxicity, as well as environmental issues.

  • Edeleva, M.; Audran, G.; Marque, S.; Bagryanskaya, E. Materials (Basel, Switzerland) 2019, 12 (5).
    Résumé : Because alkoxyamines are employed in a number of important applications, such as nitroxide-mediated polymerization, radical chemistry, redox chemistry, and catalysis, research into their reactivity is especially important. Typically, the rate of alkoxyamine homolysis is strongly dependent on temperature. Nonetheless, thermal regulation of such reactions is not always optimal. This review describes various ways to reversibly change the rate of C⁻ON bond homolysis of alkoxyamines at constant temperature. The major methods influencing C⁻ON bond homolysis without alteration of temperature are protonation of functional groups in an alkoxyamine, formation of metal⁻alkoxyamine complexes, and chemical transformation of alkoxyamines. Depending on the structure of an alkoxyamine, these approaches can have a significant effect on the homolysis rate constant, by a factor of up to 30, and can shorten the half-lifetime from days to seconds. These methods open new prospects for the application of alkoxyamines in biology and increase the safety of (and control over) the nitroxide-mediated polymerization method.

  • Fersing, C.; Basmaciyan, L.; Boudot, C.; Pedron, J.; Hatter, S.; Cohen, A.; Castera-Ducros, C.; Primas, N.; Laget, M.; Casanova, M.; Bourgeade-Delmas, S.; Piednoel, M.; Sournia-Saquet, A.; Mbou, V. B.; Courtioux, B.; Boutet-Robinet, E.; Since, M.; Milne, R.; Wyllie, S.; Fairlamb, A. H.; Valentin, A.; Rathelot, P.; Verhaeghe, P.; Vanelle, P.; Azas, N. Acs Medicinal Chemistry Letters 2019, 10 (1), 34-39.
    Résumé : Twenty nine original 3-nitroimidazo[1,2-a]pyridine derivatives, bearing a phenylthio (or benzylthio) moiety at position 8 of the scaffold, were synthesized. In vitro evaluation highlighted compound 5 as an antiparasitic hit molecule displaying low cytotoxicity for the human HepG2 cell line (CC50 > 100 mu M) alongside good antileishmanial activities (IC50 = 1-2.1 mu M) against L. donovani, L. infantum, and L. major; and good antitrypanosomal activities (IC50 = 1.3-2.2 mu M) against T. brucei brucei and T. cruzi, in comparison to several reference drugs such as miltefosine, fexinidazole, eflornithine, and benznidazole (IC50 = 0.6 to 13.3 mu M). Molecule 5, presenting a low reduction potential (E degrees = -0.63 V), was shown to be selectively bioactivated by the L. donovani type 1 nitroreductase (NTR1). Importantly, molecule 5 was neither mutagenic (negative Ames test), nor genotoxic (negative comet assay), in contrast to many other nitroaromatics. Molecule 5 showed poor microsomal stability; however, its main metabolite (sulfoxide) remained both active and nonmutagenic, making 5 a good candidate for further in vivo studies.

  • Garniron, Y.; Applencourt, T.; Gasperich, K.; Benali, A.; Ferte, A.; Paquier, J.; Pradines, B.; Assaraf, R.; Reinhardt, P.; Toulouse, J.; Barbaresco, P.; Renon, N.; David, G.; Malrieu, J. - P.; Veril, M.; Caffarel, M.; Loos, P. - F.; Giner, E.; Scemama, A. Journal of Chemical Theory and Computation 2019, 15 (6), 3591-3609.
    Résumé : Quantum chemistry is a discipline which relies heavily on very expensive numerical computations. The scaling of correlated wave function methods lies, in their standard implementation, between O(N-5) and O(e(N)), where N is proportional to the system size. Therefore, performing accurate calculations on chemically meaningful systems requires (i) approximations that can lower the computational scaling and (ii) efficient implementations that take advantage of modern massively parallel architectures. QUANTUM PACKAGE is an open-source programming environment for quantum chemistry specially designed for wave function methods. Its main goal is the development of determinant-driven selected configuration interaction (sCI) methods and multireference second-order perturbation theory (PT2). The determinant-driven framework allows the programmer to include any arbitrary set of determinants in the reference space, hence providing greater methodological freedom. The sCI method implemented in QUANTUM PACKAGE is based on the CIPSI (Configuration Interaction using a Perturbative Selection made Iteratively) algorithm which complements the variational sCI energy with a PT2 correction. Additional external plugins have been recently added to perform calculations with multireference coupled cluster theory and range-separated density-functional theory. All the programs are developed with the IRPF90 code generator, which simplifies collaborative work and the development of new features. QUANTUM PACKAGE strives to allow easy implementation and experimentation of new methods, while making parallel computation as simple and efficient as possible on modern supercomputer architectures. Currently, the code enables, routinely, to realize runs on roughly 2 000 CPU cores, with tens of millions of determinants in the reference space. Moreover, we have been able to push up to 12 288 cores in order to test its parallel efficiency. In the present manuscript, we also introduce some key new developments: (i) a renormalized second-order perturbative correction for efficient extrapolation to the full CI limit and (ii) a stochastic version of the CIPSI selection performed simultaneously to the PT2 calculation at no extra cost.

  • Garra, P.; Brunel, D.; Noirbent, G.; Graff, B.; Morlet-Savary, F.; Dietlin, C.; Sidorkin, V. F.; Dumur, F.; Duche, D.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Polymer Chemistry 2019, 10 (12), 1431-1441.
    Résumé : Ferrocene-based photoredox catalysis is proposed here for the first time. Aryl radicals generated from a Fe(II)*/Ar2I+ reaction can be used as initiating species for efficient free radical photopolymerization of methacrylate resins. Remarkably, these photoredox catalysts can also be used for redox free radical polymerization (without light) in combination with ammonium persulfate for unique access to dual cure (photochemical/thermal redox) systems. The addition of a third component (amine, phosphine or vitamin C reducing agents) enables the regeneration of the catalysts and greatly enhances the radical generation. The motivation with these dual cure systems is to develop orthogonal chemistries where a latent redox polymerization (without light) is able to cure any thickness of polymers (or composite) in combination with fast photopolymerization processes in the irradiated areas. Chemical mechanisms will be discussed in detail using cyclic voltammetry, electron spin resonance spin trapping (ESR-ST), UV-vis-NIR spectroscopy, free energy calculations and molecular modeling at the density functional theory (DFT) level. This study represents, to the best of our knowledge, the first photochemically active iron catalysts that are also efficient in thermal redox catalysis.

  • Garra, P.; Dietlin, C.; Morlet-Savary, F.; Dumur, F.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Progress in Polymer Science 2019, 94, 33-56.
    Résumé : Redox polymerizations are of huge importance throughout academic and industrial polymer science. Many authors propose the reaction of reducing (Red) and oxidizing (Ox) agents to accelerate/initiate radical or cationic polymerizations. As a result of activation energies typically below 80 kJ/mol, such reactions can occur under mild conditions, e.g., at room temperature, with reduced energy consumptions and robust in applications, such as the fabrication of composites. However, a clear definition of redox polymerization can only be found in reviews dealing with redox free radical polymerizations (FRP) published twenty years ago (or more). Therefore, a fresh and broader update is provided here for more recent work. The concepts involved when the Redand Oxagents (constituting the redox initiating system) are mixed under mild conditions are presented, followed by a discussion of the redox FRP initiating systems in bulk. Initiating systems dealing with the redox cationic polymerization (CP) are reviewed, and parallels between conventional FRP/CP and controlled polymerizations, in which redox systems are used, is provided. Many redox agents are useful in both modes. Finally, dual-cure (redox/photochemical; redox dual FRP/CP) systems is presented and selected applications are reviewed. Altogether, the state of the art for redox two-component polymerizations is provided, along with some perspectives. (C) 2019 Elsevier B.V. All rights reserved.

  • Gaudel-Siri, A.; Marchal, C.; Ledentu, V.; Gigmes, D.; Siri, D.; Charles, L. European Journal of Mass Spectrometry 2019, 25 (2), 229-238.
    Résumé : The dissociation behavior of two stable nitroxides, namely 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO center dot) and N-tert-butyl-1-diethylphosphono-2,2-dimethylpropyl nitroxide (SG1(center dot)), subjected as protonated molecules to collisional activation was investigated using a combination of different mass spectrometry experiments and theoretical calculations. Elemental composition of reaction products was derived from accurate mass data measured in high resolution tandem mass spectrometry experiments, primary fragments were distinguished from secondary ions based on both breakdown curves and MS3 data, and H/D exchange experiments were performed to support proposed structures. Postulated fragmentation pathways were then studied in terms of energetic, using the standard B3LYP/6-31G(d) method. While protonation of TEMPO center dot mainly occurred on the oxygen atom of the nitroxyl function, a series of protomers were found for SG1(center dot) with the adducted proton preferentially located onto the P=O group of this phosphorylated species. For both protonated nitroxides, major product ions measured in tandem mass spectrometry arose from reactions occurring at low energy costs via elimination of radical species. Formation of secondary fragments that were detected with low abundance when raising the activation level of both precursor ions could be rationalized with pathways proceeding via high energy transition states.

  • Ghali, M.; Brahmi, C.; Benltifa, M.; Dumur, F.; Duval, S.; Simonnet-Jegat, C.; Morlet-Savary, F.; Jellali, S.; Bousselmi, L.; Lalevee, J. Journal of Polymer Science Part a-Polymer Chemistry 2019, 57 (14), 1538-1549.
    Résumé : New polyoxometalate (POM)/polymer hybrid composites were prepared by photopolymerization under mild conditions for suitable photocatalytic processes. Polyoxometalates were incorporated in special photosensitive resins, which were photopolymerized under visible light to obtain new materials with photocatalytic activity for dye removal. The synthesized composites were characterized by real-time FT-IR, and the photocatalytic ability was investigated on Eosin-Y removal using photolysis under near

  • Guerineau, V.; Rollet, M.; Viel, S.; Lepoittevin, B.; Costa, L.; Saint-Aguet, P.; Laurent, R.; Roger, P.; Gigmes, D.; Martini, C.; Huc, V. Nature Communications 2019, 10, 113.
    Résumé : Calixarenes are cyclic oligomers obtained by condensation of suitable p-functionalised phenols with formaldehyde, usually allowing for the synthesis of the well known small calixarenes (including up to eight phenolic subunits). We report here the discovery of much larger members of this family, exhibiting sizes up to 90 phenolic subunits: the giant calixarenes. These macrocycles are obtained according to simple, easily scalable processes, in yields up to 65%. We show that the formation of these giant macrocycles is favored by an oxygencontaining-group at the para-position of the starting phenol, high concentrations of heavy alkaline bases (rubidium or cesium hydroxides) and long reaction times. A mechanism is proposed to rationalize these observations. These giant macrocycles can also be obtained in the quasi-solid state, opening interesting perspectives in the field of calixarenes chemistry. Along with their intrinsic fundamental interest, these objects are also opening interesting applicative potentialities.

  • Guselnikov, O.; Postnikov, P.; Marque, S. R. A.; Svorcik, V.; Lyutakov, O. Sensors and Actuators B-Chemical 2019, 300, 127015.
    Résumé : In this work, we present the novel analytical procedure for the detection of the radicals in the analytical solutions with an unprecedented detection limit and versatility. The proposed procedure is based on the grafting of stable 2,2,6,6-Tetramethylpiperidin-1-yeoxyl (TEMPO) radical to the surface of the SERS-active gold grating. The presence of radicals in the analytical solution induces the conversion of grafted TEMPO to N-oxoammonium salt accompanied by the appropriate peak shifts in SERS spectra. Observed changes of SERS spectra makes possible to detect the presence of radicals down to 10(-10) M concentration, far exceeding the sensitivity of common analytical methods. Proposed highly regular plasmonic background providing homogeneous distribution of electric field enhancement together with used surface decoration procedure ensuring uniform distribution of grafted TEMPO molecules, result in perfect SERS results reproducibility. Finally, the regeneration of SERS substrate was also demonstrated which is essential for repeated use of created SERS chips in radical's detection.

  • Guselnikova, O.; Marque, S. R. A.; Tretyakov, E.; Mares, D.; Jerabek, V.; Audran, G.; Joly, J. - P.; Trusova, M.; Svorcik, V.; Lyutakov, O.; Postnikov, P. Journal of Materials Chemistry A 2019, 7 (20), 12414-12419.
    Résumé : A plasmon as a stimulus opens up new opportunities for selective and regulated "from-surface" polymerization and functionalization of surfaces. Here, the first example of plasmon-assisted nitroxide-mediated polymerization (NMP) of stimuli-responsive block copolymers poly(N-isopropylacrylamide)-co-4-vinylboronic acid is reported. The growth of a polymer film at room temperature was achieved via plasmon-induced homolysis of alkoxyamines covalently attached to the surface of plasmon-active gold gratings at room temperature. Control of temperature, finite-difference time-domain method simulation of plasmon intensity distribution shift during polymerization, electron paramagnetic resonance experiments and other assays provide strong support for the plasmon-initiated mechanism of NMP. We demonstrated not only the control of the resulting polymer thickness but also the preparation of a surface-enhanced Raman spectroscopy chip for the detection of glycoproteins as a powerful example of plasmon-assisted NMP potential.

  • Ibrahim-Ouali, M.; Dumur, F. Molecules 2019, 24 (7), 1412.
    Résumé : During the past decades, the development of emissive materials for organic light-emitting diodes (OLEDs) in infrared region has focused the interest of numerous research groups as these devices can find interest in applications ranging from optical communication to defense. To date, metal complexes have been most widely studied to elaborate near-infrared (NIR) emitters due to their low energy emissive triplet states and their facile access. In this review, an overview of the different metal complexes used in OLEDs and enabling to get an infrared emission is provided.

  • Konig, N. F.; Al Ouahabi, A.; Oswald, L.; Szweda, R.; Charles, L.; Lutz, J. - F. Nature Communications 2019, 10, 3774.
    Résumé : Light-induced alteration of macromolecular information plays a central role in biology and is known to influence health, aging and Darwinian evolution. Here, we report that light can also trigger sequence variations in abiotic information-containing polymers. Sequence-coded poly (phosphodiester)s were synthesized using four phosphoramidite monomers containing either photo-sensitive or photo-inert substituents. These monomers allow different sequence manipulations. For instance, using two light-cleavable monomers containing o-nitrobenzyl ether and o-nitroveratryl ether motifs, photo-erasable digital polymers were prepared. These polymers can be decoded by tandem mass spectrometry but become unreadable after UVA exposure. The opposite behavior, i.e. photo-revealable sequences, was obtained with polymers made of two isobaric monomers containing light-cleavable o-nitrobenzyl ether and light-inert p-nitrobenzyl ether substituents. Furthermore, when the latter two monomers were used in conjunction with a third monomer bearing a light-inert OH group, site-directed photo-mutations were induced in synthetic polymers. This was used herein to change the meaning of binary sequences.

  • Kossoski, F.; Varella, M. T. do N.; Barbatti, M. Journal of Chemical Physics 2019, 151 (22), 224104.
    Résumé : A novel theoretical framework for describing the dynamics of transient anions is presented. An ensemble of classical trajectories is propagated on-the-fly, where resonance energies are computed with bound state techniques, and resonance widths are modeled with a combination of bound state and scattering calculations. The methodology was benchmarked against quantum dynamics results for model potential energy curves, and excellent agreement was attained. As a first application, we considered the electron induced dissociation of chloroethane. We found that electron attachment readily stretches the C-Cl bond, which stabilizes the transient anion within similar to 10 fs and leads to the release of fast chloride ions. Both magnitude and shape of the computed dissociative electron attachment cross sections are very similar to the available experimental data, even though we found the results to be very sensitive on the accuracy of the underlying methods. These encouraging results place the proposed methodology as a promising approach for studies on transient anions' dynamics of medium sized molecules.

  • Le Breton, N.; Longhi, S.; Rockenbauer, A.; Guigliarelli, B.; Marque, S. R. A.; Belle, V.; Martinho, M. Physical Chemistry Chemical Physics 2019, 21 (40), 22584-22588.
    Résumé : During molecular processes, protein flexibility is a fundamental property allowing protein-protein interaction. Following structural changes during these interactions is then of crucial interest. Site-Directed Spin Labeling (SDSL) combined to EPR spectroscopy is a powerful technique to follow structural modifications within proteins and during protein-protein interactions. Usual nitroxide labels target cysteine residues and afford a 3-line spectrum, whose shape is informative of the structural environment of the label. However, it is not possible to probe two regions of a protein or two partner proteins at the same time because of the overlapping of EPR signatures. Previously, we reported the design and the characterization of a spin label based on a beta -phosphorylated (PP) nitroxide yielding a 6-line spectrum. Here, we report the use of two labels with different EPR signatures, namely maleimido-proxyl (P) and PP, to follow structural changes during a protein-protein interaction process in one single experiment. As a model system, we chose a disordered protein that undergoes an induced alpha -helical folding upon binding to its partner. We show that the EPR spectrum of a mixture of labeled interacting proteins can be analyzed in terms of structural changes during the interaction. This study represents an important step forward in the extension of the panoply of SDSL-EPR approaches.

  • Le, D.; Dilger, M.; Pertici, V.; Diabate, S.; Gigmes, D.; Weiss, C.; Delaittre, G. Angewandte Chemie (International ed. in English) 2019, 58 (14), 4725-4731.
    Résumé : We report the straightforward, time-efficient synthesis of radical core-shell nanoparticles (NPs) by polymerization-induced self-assembly. A nitroxide-containing hydrophilic macromolecular precursor was prepared by ring-opening metathesis copolymerization of norbornenyl derivatives of TEMPO and oligoethylene glycol and was chain-extended in situ with norbornene in ethanolic solution, leading to simultaneous amphiphilic block copolymer formation and self-assembly. Without any intermediate purification from the monomers to the block copolymers, radical NPs with tunable diameters ranging from 10 to 110 nm are obtained within minutes at room temperature. The high activity of the radical NPs as chemoselective and homogeneous, yet readily recyclable catalysts is demonstrated through oxidation of a variety of alcohols and recovery by simple centrifugation. Furthermore, the NPs show biocompatibility and antioxidant activity in vitro.

  • Le Tohic, S.; Montana, M.; Koch, L.; Curti, C.; Vanelle, P. European Journal of Clinical Microbiology & Infectious Diseases 2019, 38 (8), 1395-1408.
    Résumé : Melioidosis is a tropical bacterial infection, rarely encountered, and poorly known by clinicians. In non-endemic areas, a misdiagnosis can lead to a fatal outcome. This study aims to identify the main characteristics of imported and diagnosed melioidosis cases in Europe to increase clinician's awareness of this diagnosis. A literature review of imported and diagnosed human melioidosis cases in Europe was performed. PubMed and Web of Science search engines were used for retrieving articles from 2000 to November 2018. Seventy-seven cases of imported melioidosis into Europe described in the literature were identified. More than half of the cases were acquired in Thailand (53%) by men (73%). Patients were usually exposed to Burkholderia pseudomallei during a holiday stay (58%) of less than 1 month (23%) and were hospitalized during the month following their return to Europe (58%). Among travelers, melioidosis is less often associated with risk factor (16%), diabetes being the most frequently comorbidity related (19%). The clinical presentation was multifaceted, pneumonia being the most common symptom (52%), followed by cardiovascular form (45%) and skin and soft tissues damages (35%). The diagnosis was obtained by culture (92%), often supplemented by morphological, biochemical, and molecular identification (23%). Misdiagnoses were common (21%). Over half of the patients received a complete and adapted treatment (56%). Mortality is lower for returning traveler (6%). Imported melioidosis cases into Europe have their own characteristics. This possibility should be considered in patients with pneumonia, fever, and/or abscess returning from endemic areas even years after.

  • Levitre, G.; Dagousset, G.; Anselm, E.; Tuccio, B.; Magnier, E.; Masson, G. Organic Letters 2019, 21 (15), 6005-6010.
    Résumé : We report herein an efficient four-component photoredox-catalyzed reaction. Under the optimized conditions using [Ru(bpy)(3)(PF6)(2)] as the photocatalyst, a wide range of terminal and internal alkenes can efficiently undergo azidoalkoxy-trifluoromethylation in the presence of Umemoto's reagent, carbonyl compound, and TMSN3, giving rise to original and highly complex molecules in a single operation.

  • Liu, R.; Gao, X.; Barbatti, M.; Jiang, J.; Zhang, G. The journal of physical chemistry letters 2019, 10 (6), 1388-1393.
    Résumé : Pure light-atom organic phosphorescent molecules have been under scientific scrutiny because they are inexpensive, flexible, and environment friendly. The development of such materials, however, faces a bottleneck problem of intrinsically small spin-orbit couplings, which can be addressed by seeking a proper balance between intersystem crossing (ISC) and fluorescence rates. Using N-substituted naphthalimides as the prototype molecule, we applied chemical modifications with several electrophilic and nucleophilic functional groups, to approach the goal. The selected electron donating groups actively restrain the fluorescence, enabling an efficient ISC to the triplet manifold. Electron withdrawing groups do not change the luminescent properties of the parent species. The changes in ISC and fluorescence rates are related to the nature of the lowest singlet state, which changes from localized excitation into charge-transfer excitation upon configuration change of excited molecules. This finding opens an alternative strategy for designing pure light-atom organic phosphorescent molecules for emerging luminescent materials applications.

  • Liu, R.; Yang, L.; Yang, T.; Huang, Y.; Barbatti, M.; Jiang, J.; Zhang, G. Journal of Physical Chemistry Letters 2019, 10 (18), 5634-5639.
    Résumé : Tuning electron-transfer (ET) rates from catalysts to substrates is important for modulating photocatalytic organic reactions. In this work, we have taken pyrene-based photocatalysts (Py's) for photocatalytic hydrodefluorination of polyfluoroarenes (FAs) as model systems and conducted a first-principles study on modulating ET rates from Py to FA via the chemical modification of Py with different electron-donating/withdrawing groups (EDGs/EWGs). The computed spatial distributions of frontier Kohn-Sham orbitals suggest that ET is energetically more favorable for Py-EDGs than for Py-EWGs. The estimated

  • Lo Presti, C.; Curti, C.; Montana, M.; Bornet, C.; Vanelle, P. Medecine Et Maladies Infectieuses 2019, 49 (1), 1-8.
    Résumé : Despite its benign characteristics, chickenpox is a childhood disease responsible for complications and deaths, particularly in the high-risk population. VariZIG (R), not commercialized in France, is a good alternative for seronegative individuals exposed to the virus and not eligible for vaccination. The efficacy of routine vaccination has been demonstrated with a decrease in chickenpox incidence and with the development of herd immunity. Over time, the protective antibody titer of vaccinated people decreases and can be maintained by two doses of the vaccine. A tetravalent measles-mumps-rubella-chickenpox vaccine, used in the United States, has a good tolerability in spite of the occurrence of fever and febrile seizures. Routine vaccination would contribute to make savings in France, by reducing direct and indirect costs of chickenpox. (C) 2018 Elsevier Masson SAS. All rights reserved.

  • Luconi, L.; Garino, C.; Vioglio, P. C.; Gobetto, R.; Chierotti, M. R.; Yakhvarov, D.; Gafurov, Z. N.; Morozov, V.; Sakhapov, I. 'yas; Rossin, A.; Giambastiani, G. Acs Omega 2019, 4 (1), 1118-1129.
    Résumé : Four metal halides of the ((PCN)-P-tBu) NiX family [X = F (1), Cl (2), Br (3), or I (4); PCN = 1-[3-[(di-tert-butylphosphino) methyl] phenyl]-1H-pyrazole] have been prepared through a direct reaction of the corresponding anhydrous NiX2 salts and the unsymmetrical PCN pincer ligand. Structural information from single-crystal X-ray data, F-19 solution nuclear magnetic resonance, and combined electrochemical results [cyclic voltammetry (CV) and in situ electron paramagnetic resonance spectro-electrochemistry] reveal that the fluoride complex 1 is different from the other halides 2-4 in terms of electro-oxidation behavior (presence of three anodic peaks instead of one in the CV profile). 1 is also different from its symmetrical analogue ((PCP)-P-tBu) NiF in terms of halogen-bonding capability toward the halogen-bond donor, iodopentafluorobenzene (C6F5I, IPFB). The positive Delta S degrees value for the formation of the 1...IPFB adduct inferred from the van't Hoff plots is in agreement with the existence of (1.H2O) aggregates in solution, not present in 2-4. The high nucleophilicity of the fluoride ligand and the simultaneous presence of electrophilic (acidic) protons on the sidearm of the pyrazole ligand are at the origin of the observed phenomena.

  • Maniego, A. R.; Sutton, A. T.; Guillaneuf, Y.; Lefay, C.; Destarac, M.; Fellows, C. M.; Castignolles, P.; Gaborieau, M. Polymer Chemistry 2019, 10 (19), 2469-2476.
    Résumé : Poly(acrylic acid) s, PAAs and poly(sodium acrylate) s, PNaAs were characterized in detail. Mn was determined using size-exclusion chromatography, H-1 and C-13 NMR spectroscopy. There is no agreement between the results from different methods, possibly due to the surprisingly low solubility of PAA/PNaA in usual solvents such as dioxane, DMSO, and water. Clustering in PAA/PNaA (due to branching) should affect the molar mass determination by SEC and NMR spectroscopy differently. The degree of branching (DB) of PAAs and PNaAs obtained by reversible-deactivation radical polymerization (RDRP) and conventional radical polymerization (CVRP) was quantified by C-13 NMR spectroscopy. Previous investigations indicated that DB in poly(n-butyl acrylate) is lower when synthesized by RDRP than when synthesized by CVRP (without chain transfer agent, CTA). In the present work no substantial differences in DB were observed between PAAs synthesized via RDRP and CVRP in otherwise similar conditions of solvent and temperature. We believe that further investigations are necessary to know whether there are substantial differences in DB between poly(n-butyl acrylate) s synthesized by RDRP and the ones synthesized by CVRP or not. The DB values are higher for PAAs synthesized in dioxane than for PAAs/PNaAs synthesized in water, and adding ethanol to water further lowers the DB values. H-Bonding of ethanol with PAA/PNaA or patching of the mid-chain radical by ethanol can lead to the decrease in DB. The polymerization conditions, polymerization temperature but also solvent, thus allow some tailoring of DB values depending on desired applications. The present manuscript provides an extended, reliable set of experimental data for PAA looking at the influence of polymerization process (controlled versus conventional), temperature, and solvent on DB. This will form a valuable basis for meaningful further in-depth kinetic investigations.

  • Marin, A. C.; Culcasi, M.; Cassien, M.; Stocker, P.; Thetiot-Laurent, S.; Robillard, B.; Chinnici, F.; Pietri, S. Food Chemistry 2019, 285, 67-76.
    Résumé : The efficacy against oxidative degradation in model and sulphite-free white wines of two commercial, insoluble chitosans (one being approved for winemaking) were investigated by electron paramagnetic resonance (EPR). Both compounds at various doses significantly inhibited the formation of alpha-(4-pyridyl-1-oxide)-N-t-butylnitrone (4-POBN)-1-hydroxyethyl adducts under normal wine storage conditions. Pre-incubation with 2 g/L chitosan followed by filtration had a better effect than adding 50 mg/L sulphur dioxide to the experimental Chardonnay wine on the release of 4-POBN adducts after 6 days of incubation with 100 mu M iron(II). In a relevant photo-oxidative system acetaldehyde formation was significantly reduced after 6 days of incubation. Parallel EPR tests were performed to assess the importance of metal chelation (iron and copper) versus direct scavenging of hydroxyl radicals on the effect of chitosan. The present data support the potentiality of using biocompatible chitosan as a healthier complement and/or alternative to sulphur dioxide against white wine oxidative spoilage.

  • Mathias, F.; Curti, C.; Montana, M.; Bornet, C.; Vanelle, P. European Journal of Clinical Microbiology & Infectious Diseases 2019, 38 (2), 209-231.
    Résumé : Clostridium difficile infections (CDI) dramatically increased during the last decade and cause a major public health problem. Current treatments are limited by the high disease recurrence rate, severity of clinical forms, disruption of the gut microbiota, and colonization by vancomycin-resistant enterococci (VRE). In this review, we resumed current treatment options from official recommendation to promising alternatives available in the management of adult CDI, with regard to severity and recurring or non-recurring character of the infection. Vancomycin remains the first-line antibiotic in the management of mild to severe CDI. The use of metronidazole is discussed following the latest US recommendations that replaced it by fidaxomicin as first-line treatment of an initial episode of non-severe CDI. Fidaxomicin, the most recent antibiotic approved for CDI in adults, has several advantages compared to vancomycin and metronidazole, but its efficacy seems limited in cases of multiple recurrences. Innovative therapies such as fecal microbiota transplantation (FMT) and antitoxin antibodies were developed to limit the occurrence of recurrence of CDI. Research is therefore very active, and new antibiotics are being studied as surotomycin, cadazolid, and rinidazole.

  • Medbouhi, A.; Benbelaid, F.; Djabou, N.; Beaufay, C.; Bendahou, M.; Quetin-Leclercq, J.; Tintaru, A.; Costa, J.; Muselli, A. Molecules 2019, 24 (14), 2575.
    Résumé : The chemical composition of essential oils extracted from aerial parts of Eryngium campestre collected in 37 localities from Western Algeria was characterized using GC-FID and GC/MS analyses. Altogether, 52 components, which accounted for 70.1 to 86.8% of the total composition oils were identified. The main compounds were Germacrene D (0.4-53.4%), Campestrolide (1.6-35.3%), Germacrene B (0.2-21.5%), Myrcene (0.1-8.4%), alpha-Cadinol (0.2-7.6%), Spathulenol (0.1-7.6%), Eudesma-4(15)-7-dien-1-beta-ol (0.1-7.6%) and tau-Cadinol (0.3-5.5%). The chemical compositions of essential oils obtained from separate organs and during the complete vegetative cycle of the plant were also studied. With the uncommon 17-membered ring lactone named Campestrolide as the main component, Algerian E. campestre essential oils exhibited a remarkable chemical composition. A study of the chemical variability using statistical analysis allowed the discrimination of two main clusters according to the geographical position of samples. The study contributes to the better understanding of the relationship between the plant and its environment. Moreover, the antimicrobial activity of the essential oil was assessed against twelve strains bacteria and two yeasts involved in foodborne and nosocomial infections using paper disc diffusion and dilution agar assays. The in vitro study demonstrated a strong activity against Gram-positive strains such as S. aureus, B. cereus, and E. faecalis. The cytotoxicity and antiparasitic activities (on Lmm and Tbb) of the collective essential oil and one sample rich in campestrolide, as well as some enriched fractions or fractions containing other terpenic compounds, were also analyzed. Campestrolide seems to be one compound responsible for the cytotoxic and antileishmanial effect, while myrcene or/and trans-beta-farnesene have a more selective antitrypanosomal activity.

  • Mokbel, H.; Anderson, D.; Plenderleith, R.; Dietlin, C.; Morlet-Savary, F.; Dumur, F.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Progress in Organic Coatings 2019, 132, 50-61.
    Résumé : This investigation presents the use of a photoredox catalyst "G1" as a photoinitiating system for free radical/cationic hybrid polymerization under mild irradiation conditions. The G1 system (G1/iodonium salt/N-vinylcarbazole), can simultaneously initiate the free radical and cationic polymerization reactions upon exposure to a visible (405 nm) light from a Light Emitting Diode (LED) source. The multicomponent G1 system is able to simultaneously generate radical and cationic species through a catalytic photoredox process. The curing of thin samples (25 mu m), thick samples (1.4 mm) as well as the manufacture of hybrid system/glass fibers composites ( 2 to 4 mm thickness) was realized and the influence of the ratio of cationic/radical monomer blends on the polymerization kinetics was studied. The use of G1 in visible light photoinitiating system for the access to composites and 3D printing experiments was particularly outlined. G1 was also shown to have low levels of migration from the cured materials. When compared to reference materials ("F1", a similar copper complex and an anthracene derivative, dibutoxy anthracene), G1 showed better polymerization efficiency. The initiation efficiency was investigated through the real-time Fourier transform infrared (RT-FTIR) spectroscopy and optical pyrometry. Dynamical Mechanical Analysis has been used to determine the glass temperature transition of the cured hybrid system as a complementary technique.

  • Mondal, P.; Huix-Rotllant, M. Physical Chemistry Chemical Physics 2019, 21 (17), 8874-8882.
    Résumé : Cryptochrome is a blue-light absorbing flavoprotein containing a flavin adenine dinucleotide (FAD) cofactor. FAD can accept up to two electrons and two protons, which can be subsequently transferred to substrates present in the binding pocket. It is well known that reactive oxygen species are generated when triplet molecular oxygen is present in the cavity. Here, we investigate the formation and stability of radical oxygen species in Drosophila melanogaster cryptochrome using molecular dynamics simulations and electronic structure calculations. We find that the superoxide and hydroxyl radicals in doublet spin states are stabilized in the pocket due to the attractive electrostatic interactions and hydrogen bonding with partially reduced FAD. These findings validate from a molecular dynamics perspective that [FAD(-)-HO2] or [FADH-O-2(-)] can be alternative radical pairs at the origin of magnetoreception.

  • Mondal, T.; Greff, V.; Petit, B. E.; Charles, L.; Lutz, J. - F. Acs Macro Letters 2019, 8 (8), 1002-1005.
    Résumé : Sequence-defined poly(N-substituted urethanes) were synthesized via a solid-phase iterative protocol including two successive orthogonal coupling steps: the formation of an activated carbonate and its chemoselective reaction with the secondary amine group of amino alcohol building blocks. This simple method was used to write binary information on the formed polymers using four-coded molecules, 2-(methylamino)ethanol, 2-(ethylamino)ethanol, 2-(propylamino)ethanol, and 2-(butylamino)ethanol, symbolizing binary dyads 00, 01, 10, and 11, respectively. The method is fast and allows synthesis of uniform oligomers and polymers with controlled lengths (4-mer to 28-mer) and digital information sequences. Furthermore, the coded poly(N-substituted urethanes) were easily characterized by electrospray mass spectrometry and decoded by tandem mass spectrometry. Overall, these digital macromolecules offer interesting advantages over conventional sequence-coded polyurethanes, i.e., synthesis of longer chains, reduced synthesis times, and better solubility and processing in common organic solvents.

  • Montana, M.; Mathias, F.; Terme, T.; Vanelle, P. European Journal of Medicinal Chemistry 2019, 163, 136-147.
    Résumé : Cancer is a leading cause of death and a major health problem worldwide. While many effective anticancer agents are available, the majority of drugs currently on the market are not specific, raising issues like the common side effects of chemotherapy. However, recent research hold promise for the development of more efficient and safer anticancer drugs. Quinoxaline and its derivatives are becoming recognized as a novel class of chemotherapeutic agents with activity against different tumors. The present review compiles and discusses studies concerning the therapeutic potential of the anticancer activity of quinoxaline derivatives, covering articles published between July 2013 and July 2018. (C) 2018 Elsevier Masson SAS. All rights reserved.

  • Montana, M.; Mathias, F.; Rathelot, P.; Lacroix, J.; Vanelle, P. Journal of Educational Evaluation for Health Professions 2019, 16, 19.
    Résumé : Purpose: To describe our experiences with the development of an elective course on the pharmacist's role in disaster management for third-year pharmacy students and to evaluate its effects on students' knowledge and their perceptions of the introduction of this course into the curriculum. Methods: An expert team of physicians, surgeons, and pharmacists of the Service de Sante des Armees, pharmacists teaching at the Faculty of Pharmacy, and pharmacists from the Bataillon des Marins Pompiers de Marseille developed a program consisting of 30 hours of modules on disaster response training based on previously published recommendations, a literature analysis, and international guidelines. Students' knowledge of key competencies was assessed after some teaching sessions through a multiple-choice quiz. Students' self-perceived knowledge, perceptions of teaching quality, and degree of satisfaction were evaluated through a voluntary survey after the last teaching session on November 15. Results: The final curriculum consisted of 6 modules. Students' knowledge of key competencies was assessed using multiple-choice quizzes, with a mean score of 19 of 25. Almost all students (98.3%) reported that this training program improved their knowledge of the pharmacist's role in disaster management, and 79.3% stated that they would recommend this optional course. Conclusion: This training course demonstrated the potential to increase the number of pharmacists prepared to respond to disasters. It also expanded students' understanding of the pharmacist's role and stimulated their interest in emergency preparedness. Further refinement of the program, including a simulation of mass triage in an emergency setting, will be conducted next year.

  • Nasreldin, M.; Delattre, R.; Marchiori, B.; Ramuz, M.; Maria, S.; de la Tocnaye, J. L. de B.; Djenizian, T. Apl Materials 2019, 7 (3), 031507.
    Résumé : In this work, it is reported the fabrication of highly stretchable electrodes on a polydimethylsiloxane substrate. A laser ablation technique is used to design lithium nickel manganese oxide micropillars supported on serpentine Al interconnects. Morphological, mechanical, and chemical analyses have been investigated by scanning electron microscopy, optical microscopy, and energy dispersive X-Ray spectroscopy. We show that unlike compact and continuous electrode thin-films, vertical micropillar structures supported on Al serpentines can be stretched up to 70% without structural damage, which opens a new alternative for the fabrication and development of truly stretchable devices such as stretchable micro-batteries. (C) 2019 Author(s).

  • Oswald, L.; Al Ouahabi, A.; Laure, C.; Amalian, J. - A.; Charles, L.; Lutz, J. - F. Journal of Polymer Science Part a-Polymer Chemistry 2019, 57 (3), 403-410.
    Résumé : Soluble supports, with optimal molecular structures for iterative oligomer synthesis, were prepared by atom transfer radical copolymerization of styrene with Fmoc-amino ethyl methacrylate. Size exclusion chromatography and nuclear magnetic resonance indicated formation of copolymers with controlled chain lengths, chain ends, dispersity, and comonomer compositions. These polymers were afterward subjected to two subsequent modifications steps: (a) the debromination of their omega-chain ends via a tributyltin hydride treatment and (b) the removal of the Fmoc-protecting groups in acidic conditions, thus leading to bromine-free copolymers with a precise primary amine loading capacity. These universal amine-containing precursors were then derived into a variety of functional supports. A glycine-loaded Wang-type soluble polystyrene support was prepared in two steps and tested for peptide synthesis as well as for the preparation of digital oligo(alkoxyamine amide)s. In both cases, it was possible to obtain uniform sequence-defined oligomers as evidenced by electrospray ionization tandem mass spectrometry. However, each type of oligomer required specific experimental conditions and therefore soluble supports with an adapted loading capacity for optimal synthesis. Furthermore, the amine-containing universal precursors were also transformed into soluble supports for iterative phosphoramidite chemistry. A support was specifically conceived for the iterative synthesis of abiotic digital oligo(phosphodiester)s and another one was designed for oligonucleotide synthesis. (c) 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 403-410

  • Pereira Rodrigues, G.; Lopes de Lima, T. M.; de Andrade, R. B.; Ventura, E.; do Monte, S. A.; Barbatti, M. The journal of physical chemistry. A 2019, 123 (10), 1953-1961.
    Résumé : High-level multireference electronic structure calculations have been performed to study the Cl- yield from photoexcited CF3CH2Cl (HCFC-133a). The analysis of this process tells that it relates to an electron transfer from the carbon to the Cl atom, forming a highly polar contact ion-pair complex, CF3HCH+···Cl-, in the excited (S3) state. This complex has a strong binding energy of 3.53 eV, from which 0.47 eV is due to an underlying hydrogen bond. Through comparison with the results obtained for the prototype CH3Cl system, where a similar ion-pair state associated with Cl- formation has also been observed, it is suggested that photodissociation of HCFC-133a can also yield Cl- through an analogous process. This hypothesis is further supported by nonadiabatic dynamics simulations, which shows formation of the ion-pair complex in the subpicosecond time scale.

  • Pertici, V.; Pin-Barre, C.; Rivera, C.; Pellegrino, C.; Laurin, J.; Gigmes, D.; Trimaille, T. Biomacromolecules 2019, 20 (1), 149-163.
    Résumé : Injectable hydrogels are promising platforms for tissue engineering and local drug delivery as they allow minimal invasiveness. We have here developed an injectable and biodegradable hydrogel based on an amphiphilic PNIPAAm-b-PLA-b-PEG-b-PLA-b-PNIPAAm pentablock copolymer synthesized by ring-opening polymerization/nitroxide-mediated polymerization (ROP/NMP) combination. The hydrogel formation at around

  • Phan, T. N. T.; Issa, S.; Gigmes, D. Polymer International 2019, 68 (1), 7-13.
    Résumé : Nanostructured block copolymer electrolytes (BCEs) based on poly(ethylene oxide) (PEO) are considered as promising candidates for solid-state electrolytes in high energy density lithium metal batteries (LMBs). Because of their self-assembly properties, they confer on electrolytes both high mechanical strength and sufficient ionic conductivity, which linear PEO cannot provide. Two types of PEO-based BCEs are commonly known. There are the traditional ones, also called dual-ion conducting BCEs, which are a mixture of block copolymer chains and lithium salts. In these systems, the cations and anions participate in the conduction, inducing a concentration polarization in the electrolyte, thus leading to poor performances of LMBs. The second family of BCEs are single-lithium-ion conducting BCEs (SIC-BCEs), which consist of anions being covalently grafted to the polymer backbone, therefore involving conduction by lithium ions only. SIC-BCEs have marked advantages over dual-ion conducting BCEs due to a high lithium ion transference number, absence of anion concentration gradients as well as low rate of lithium dendrite growth. This review focuses on the recent developments in BCEs for applications in LMBs with particular emphasis on the physicochemical and electrochemical properties of these materials. (c) 2018 Society of Chemical Industry

  • Pieri, E.; Ledentu, V.; Sahlin, M.; Dehez, F.; Olivucci, M.; Ferre, N. Journal of Chemical Theory and Computation 2019, 15 (8), 4535-4546.
    Résumé : Anabaena Sensory Rhodopsin (ASR), a microbial photoactive protein featuring the retinal chromophore in two different conformations, exhibits a pH-dependent electronic absorption spectrum. Using the recently developed CpHMD-then-QM/MM multiscale protocol applied to ASR embedded in a membrane model, the pH-induced changes in its maximum absorption wavelength have been reproduced and analyzed. While the acidic tiny red-shift is essentially correlated with the deprotonation of an aspartic acid located on the ASR extracellular side, the larger blue-shift experimentally reported at pH values larger than 5 involves a cluster of titrating residues sitting on the cytoplasmic side. The ASR pH-dependent spectrum is the consequence of the competitive stabilization of retinal ground and excited states by the protein electrostatic potential.

  • Pigot, C.; Dumur, F. Materials 2019, 12 (4), 662.
    Résumé : The fabrication of macromolecular organic structures on surfaces is one major concern in materials science. Nanoribbons, linear polymers, and porous nanostructures have gained a lot of interest due to their possible applications ranging from nanotemplates, catalysis, optoelectronics, sensors, or data storage. During decades, supramolecular chemistry has constituted an unavoidable approach for the design of well-organized structures on surfaces displaying a long-range order. Following these initial works, an important milestone has been established with the formation of covalent bonds between molecules. Resulting from this unprecedented approach, various nanostructures of improved thermal and chemical stability compared to those obtained by supramolecular chemistry and displaying unique and unprecedented properties have been developed. However, a major challenge exists: the growth control is very delicate and a thorough understanding of the complex mechanisms governing the on-surface chemistry is still needed. Recently, a new approach consisting in elaborating macromolecular structures by combining consecutive steps has been identified as a promising strategy to elaborate organic structures on surface. By designing precursors with a preprogrammed sequence of reactivity, a hierarchical or a sequential growth of 1D and 2D structures can be realized. In this review, the different reaction combinations used for the design of 1D and 2D structures are reported. To date, eight different sequences of reactions have been examined since 2008, evidencing the intense research activity existing in this field.

  • Pigot, C.; Noirbent, G.; Bui, T. - T.; Peralta, S.; Gigmes, D.; Nechab, M.; Dumur, F. Materials 2019, 12 (8), 1342.
    Résumé : A series of ten push-pull chromophores comprising 1H-cyclopenta[b]naphthalene-1,3(2H)-dione as the electron-withdrawing group have been designed, synthesized, and characterized by UV-visible absorption and fluorescence spectroscopy, cyclic voltammetry and theoretical calculations. The solvatochromic behavior of the different dyes has been examined in 23 solvents and a positive solvatochromism has been found for all dyes using the Kamlet-Taft solvatochromic relationship, demonstrating the polar form to be stabilized in polar solvents. To establish the interest of this polyaromatic electron acceptor only synthesizable in a multistep procedure, a comparison with the analog series based on the benchmark indane-1,3-dione (1H-indene-1,3(2H)-dione) has been done. A significant red-shift of the intramolecular charge transfer band has been found for all dyes, at a comparable electron-donating group. Parallel to the examination of the photophysical properties of the different chromophores, a major improvement of the synthetic procedure giving access to 1H-cyclopenta[b]naphthalene-1,3(2H)-dione has been achieved.

  • Pigot, C.; Noirbent, G.; Peralta, S.; Duval, S.; Nechab, M.; Gigmes, D.; Dumur, F. Helvetica Chimica Acta 2019.
    Résumé : An unprecedented nucleophilic addition of piperidine on an electron acceptor, namely, 2-(3-oxo-2,3-dihydro-1H-cyclopenta[b]naphthalen-1-ylidene)malononitrile is reported. This unexpected behavior was observed during the synthesis of push-pull dyes using the classical Knoevenagel reaction. To overcome this drawback, use of diisopropylethylamine (DIPEA) enabled to produce the expected dyes PP1 and PP2. The optical and electrochemical properties of the different dyes were examined. Theoretical calculations were also carried out to support the experimental results. To evidence the higher electron-withdrawing ability of this electron acceptor, a comparison was established with two dyes (PP3 and PP4) comprising its shorter analogue.

  • Polyak, I.; Hutton, L.; Crespo-Otero, R.; Barbatt, M.; Knowles, P. J. Journal of Chemical Theory and Computation 2019, 15 (7), 3929-3940.
    Résumé : A full-dimensional simulation of the photodissociation of 1,3-cyclohexadiene in the manifold of three electronic states was performed via nonadiabatic surface hopping dynamics using extended multistate complete active space second-order perturbation (XMS-CASPT2) electronic structure theory with fully analytic nonadiabatic couplings. With the 47 +/- 8% product quantum yield calculated from the 136 trajectories, generally 400 fs-long, and an estimated excited lifetime of 89 +/- 9 fs, our calculations provide a detailed description of the nonadiabatic deactivation mechanism, showing the existence of an extended conical intersection seam along the reaction coordinate. The nature of the preferred reaction pathways on the ground state is discussed and extensive comparison to the previously published full dimensional dynamics calculations is provided.

  • Poullin, P.; Delmotte, N.; Sanderson, F.; Roche, M.; Gensollen, S. Transfusion and apheresis science : official journal of the World Apheresis Association : official journal of the European Society for Haemapheresis 2019, 102587-102587.
    Résumé : BACKGROUND: Octaplas LG is the first plasma with marketing authorisation, available in France only since February 2016. This is a double viral inactivated and prion reduced solvent/detergent fresh frozen plasma. Clinical data on Octaplas LG use in thrombotic microangiopathy (TMA) remains very limited. In May 2017, we were the first hospital in France to benefit of this new plasma product now dispensed by hospital pharmacies. We present a prospective review of all therapeutic plasma exchange (TPE) procedures for TMA patients in our hospital to evaluate the new delivery circuit, the efficacy and the adverse events (AE) related to this plasma. STUDY DESIGN AND METHODS: We prospectively reviewed 166 TPE procedures where Octaplas LG was used as replacement fluid in 15 consecutive TMA patients required TPE in our hospital from May 2017 until December 2018. RESULTS: The total replacement plasma volume administered was 763 L (3818 units) with a median on 32 L (range 6-157) per episode. Remission was achieved in all cases after a median of 7 TPE per patient's episode. No exacerbation nor relapse were noted. One patient presented a grade 1 citrate reaction, and another patient an allergic reaction. We deplored pulmonary embolism in 2 patients. CONCLUSION: In our experience OctaplasLG was well-tolerated and was effective at inducing a full clinical remission. Although two PE were noted, the relationship to OctaplasLG in unclear. The new dispensing circuit through the hospital pharmacy has proven to be safe and efficient.

  • Poyer, S.; Chendo, C.; Laure, C.; Lutz, J. - F.; Siri, D.; Charles, L. International Journal of Mass Spectrometry 2019, 438, 29-35.
    Résumé : Information could be stored in the backbone of sequence-defined oligo(alkoxyamine amide)s based on coded amide moieties, and further retrieved by MS/MS sequencing since their collision-induced dissociation only proceeded via competitive homolysis of alkoxyamine linkages. However, when occurring at chain ends, C-ON bond homolysis did not yield the set of complementary product ions expected from such a charge-remote reaction. The actual role of the adducted proton on the dissociation mechanism was then investigated. Using a set of tri(alkoxyamine amide)s that each contained two C-ON bonds, theoretical calculations first showed that protonation most favorably occurred at nitroxide moieties or at the central amide group compared to terminal amides. This result explained why the fragment at the left-hand side of the first C-ON bond was always released as a radical and never detected as a charged product. These calculations also showed that tri(alkoxyamine amide)s would exist as different protomers that could be experimentally evidenced for some of the studied species by traveling wave ion mobility spectrometry (TWIMS). TWIMS-MS/MS experiments were then performed for individual study of the IMS-resolved protomer. So-obtained data suggested that C-ON bond cleavage did not occur when the nitroxide nitrogen was protonated. However, calculations performed on optimized structures evidenced that, prior to alkoxyamine homolysis, the proton adducted to the nitroxide could be transferred onto the nearby amide oxygen atom, hence permitting to rationalize TWIMS-MS/MS data. (C) 2018 Elsevier B.V. All rights reserved.

  • Rakotonirina, M. D.; Baron, M.; Siri, D.; Gaudel-Siri, A.; Quinebeche, S.; Flat, J. - J.; Gigmes, D.; Cassagnau, P.; Beyou, E.; Guillaneuf, Y. Polymer Chemistry 2019, 10 (31), 4336-4345.
    Résumé : Acyloxyimides as a new H-abstracting agent have been developed for the radical grafting of maleic anhydride (MA) onto polyethylene in the melt state. Their model decomposition in DMSO-d6 as well as in tetradecane that mimics polyolefins was performed. These studies confirmed first the complete decomposition of N-acetoxyphthalimide (NAPI) in 1 hour at 180 degrees C by a N-O bond dissociation mechanism and also the patching of the produced macroradicals by the phthalimide group. The reaction was then performed in a mini-extruder at 190-250 degrees C and the hydrogen abstraction ability of N-acyloxyphthalimide (NAP)-, N-acyloxynaphthalimide (NANP)- and N-acyloxysuccinimide (NAS)-based derivatives was demonstrated. Optimal experimental conditions were determined by varying the initial MA content and the degree of grafting of MA was quantified by infrared spectroscopy. The MA grafting degree was as high as 2.98 wt% when using tBu-NAP as the H-abstracting agent at 230 degrees C with only a slight modification of the PE chain structures as proved by rheological experiments while the use of a peroxide (L101) led to a lower grafting degree (1.9 wt%) and a cross-linking of the polymer chains, confirmed by the three-five fold higher complex viscosity.

  • Redon, S.; Kosso, A. R. O.; Broggi, J.; Vanelle, P. Synthesis-Stuttgart 2019, 51 (19), 3758-3764.
    Résumé : The first ipso-selenocyanation of arylboronic acids is achieved using selenium dioxide and malononitrile under mild conditions. The reaction is successful even without metal or base in DMSO. The major advantages of this new method are an easy set-up, excellent yields, and the use of odorless and inexpensive selenium reagents. Basic conditions subsequently afford new access to diaryldiselenides in good yields without isolating the organoselenocyanate intermediates.

  • Rolere, S.; Monge, S.; Rakotonirina, M. D.; Guillaneuf, Y.; Gigmes, D.; Robin, J. - J. Journal of Polymer Science Part a-Polymer Chemistry 2019, 57 (2), 120-129.
    Résumé : Chemical modification of poly(lactic acid) (PLA) with N-acetoxy-phthalimide (NAPI) was performed in the melt by reactive extrusion, without using any peroxide initiator. The aminyl and nitroxide radicals produced from the NAPI thermal degradation, were, respectively, used (a) to create PLA macroradicals, and (b) to functionalize the PLA samples through nitroxide radical coupling. Depending on the extrusion temperature and the initial NAPI concentration, grafting rates up to 0.24 mol % were measured, modifying the PLA optical properties. This study represents an original new way of modification of PLA without the use of conventional peroxide initiators. Indeed, the undesirable side reactions (PLA branching or crosslinking) usually observed when using peroxides to initiate the radical grafting of PLA were avoided when using NAPI. (c) 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 120-129

  • Rolere, S.; Monge, S.; Rakotonirina, M. D.; Guillaneuf, Y.; Gigmes, D.; Robin, J. - J. Journal of Polymer Science Part a-Polymer Chemistry 2019, 57 (8), 917-928.
    Résumé : Radical grafting of poly(lactide) (PLA) during postpolymerization reactive extrusion is usually done with peroxide initiation, leading to undesirable side reactions (branching or crosslinking) and to difficulties to control the process parameters as well as the final macromolecular structure. The use of N-acetoxy-phthalimide (NAPI) was investigated as an alternative to peroxides for the functionalization in the melt of PLA with N-phenylmaleimide (PhM) monomer. The use of NAPI was found to lead to similar grafting rates in comparison to peroxides, with a better control of the PLA macromolecular structure, due to the formation of nitroxide radicals that combine with the produced macroradicals. Also, the grafting site on PLA backbone was identified after hydrolysis of grafted PLA. Above an optimal PhM concentration, homopolymerization of the monomer was also highlighted. (c) 2019 Wiley Periodicals, Inc.

  • Salnikov, E. S.; Aussenac, F.; Abel, S.; Purea, A.; Tordo, P.; Ouari, O.; Bechinger, B. Solid State Nuclear Magnetic Resonance 2019, 100, 70-76.
    Résumé : Whereas specially designed dinitroxide biradicals, reconstitution protocols, oriented sample geometries and NMR probes have helped to much increase the DNP enhancement factors of membrane samples they still lag considerably behind those obtained from glasses made of protein solutions. Here we show that not only the MAS rotor material but also the distribution of the membrane samples within the NMR rotor have a pronounced effect on the DNP enhancement. These observations are rationalized with the cooling efficiency and the internal properties of the sample, monitored by their T-1 relaxation, microwave ON versus OFF signal intensities and DNP effect. The data are suggestive that for membranes the speed of cooling has a pronounced effect on the membrane properties and concomitantly the distribution of biradicals within the sample.

  • Schwinn, K.; Ferre, N.; Huix-Rotllant, M. Journal of Chemical Physics 2019, 151 (4), 041102.
    Résumé : In electrostatic embedding mixed quantum and molecular mechanics (QM/MM) approaches, the QM charge distribution is polarized by the electrostatic interaction with the MM environment. Analytic derivatives of expectation values of operators are required to extract properties such as vibrational spectra. These derivatives usually require solving a set of coupled perturbed equations for each nucleus/atom in the system, thus becoming prohibitive when the MM subsystem contains thousands of atoms. In the context of Electrostatic Potential Fitting (ESPF) QM/MM, we can easily overcome this bottleneck by defining a set of auxiliary coupled perturbed equations called the Q-vector equations. The Q-vector method scales only with the size of the QM subsystem, producing an effective charge tensor that leads to the atomic charge derivative after contraction with the MM electrostatic potential gradient. As an example, we use the charge derivatives as an analysis tool to identify the most important chromophore-polarizing amino-acids in plant cryptochrome. This finding opens up the route of defining polarizable force fields and simulating vibrational spectroscopy using ESPF QM/MM electrostatic embedding at an affordable computational cost.

  • Spitz, C.; Mathias, F.; Pechine, S.; Doan, T. H. D.; Innocent, J.; Pellissier, S.; Di Giorgio, C.; Crozet, M. D.; Janoir, C.; Vanelle, P. Chemmedchem 2019, 14 (5), 561-569.
    Résumé : Metronidazole is one of the first-line treatments for non-severe Clostridium difficile infections (CDI). However, resistance limits its use in cases of severe and complicated CDI. Structure-activity relationships previously described for the 5-nitroimidazole series have shown that functionalization at the 2- and 4-positions can impart better activity against parasites and anaerobic bacteria than metronidazole. Herein we report the synthesis of new 2,4-disubstituted 5-nitroimidazole compounds that show potent antibacterial activity against C. difficile. We used a vicarious nucleophilic substitution of hydrogen (VNS) reaction to introduce a phenylmethylsulfone at the 4-position and a unimolecular radical nucleophilic substitution (S(RN)1) reaction to introduce an ethylenic function at the 2-position of the 5-nitroimidazole scaffold.

  • Tesfaye, A. T.; Dumur, F.; Gigmes, D.; Maria, S.; Monconduit, L.; Djenizian, T. Scientific Reports 2019, 9, 4301.
    Résumé : The high failure strain of thermoplastic elastomers (TPEs) is a very desirable feature for rechargeable Li-ion batteries by improving the lifetime of high specific capacity anode materials that undergo mechanical fractures induced by large volume variations. In this work, poly(styrene-b-2-hydroxyethyl acrylate) called PS-b-PH EA was synthesized by a nitroxide meditated polymerization method. Owing to the use of a specific polystyrene macroinitiator (SG1), a suitable TPE copolymer with long hydroxyethyl acrylate blocks to ensure good mechanical properties is obtained for the first time. We show that the electrochemical properties of the PS-b-PHEA-coated SnSb anode are drastically improved by suppressing the crack formation at the surface of the electrode. Indeed, electrochemical characterization revealed that a high and stable gravimetric capacity over 100 cycles could be achieved. Moreover, excellent capacity reversibility was achieved when cycled at multiple C-rates and fast kinetics confirming the strong protection role of the polymer. The advanced chemical and mechanical properties of PS-b-PHEA open up promising perspectives to significantly improve the electrochemical performance of all electrodes that are known to suffer from large volume variations.

  • Thureau, P.; Carvin, I.; Ziarelli, F.; Viel, S.; Mollica, G. Angewandte Chemie-International Edition 2019, 58 (45), 16047-16051.
    Résumé : Vicinal scalar couplings ((3)J) are extensively used for the conformational analysis of organic compounds in the liquid state through empirical Karplus equations. In contrast, there are no examples of such use for the structural investigation of solids. With the support of first principles calculations, we demonstrate here that C-13-(13)C(3)J coupling constants ((3)J(CC)) measured on a series of isotopically enriched solid amino acids and sugars can he related to dihedral angles by a simple Karplus-like relationship, and we provide a parameterized Karplus function "the conformational analysis of organic molecular crystals. Under the experimental conditions discussed, torsional angles can be estimated from the experimental (3)J(CC) values with an accuracy of 10 degrees using this function. These results open new perspectives towards the use of (3)J(CC), as a new analytical tool that could considerably simplify structure determination of functional organic solids.

  • Thureau, P.; Juramy, M.; Ziarelli, F.; Viel, S.; Mollica, G. Solid state nuclear magnetic resonance 2019, 99, 15-19.
    Résumé : A method based on highly concentrated radical solutions is investigated for the suppression of the NMR signals arising from solvents that are usually used for dynamic nuclear polarization experiments. The presented method is suitable in the case of powders, which are impregnated with a radical-containing solution. It is also demonstrated that the intensity and the resolution of the signals due to the sample of interest is not affected by the high concentration of radicals. The method proposed here is therefore valuable when sensitivity is of the utmost importance, namely samples at natural isotopic abundance.

  • Thureau, P.; Sturniolo, S.; Zilka, M.; Ziarelli, F.; Viel, S.; Yates, J. R.; Mollica, G. Magnetic resonance in chemistry : MRC 2019.
    Résumé : Structure determination of functional organic compounds remains a formidable challenge when the sample exists as a powder. Nuclear magnetic resonance crystallography approaches based on the comparison of experimental and Density Functional Theory (DFT)-computed 1 H chemical shifts have already demonstrated great potential for structure determination of organic powders, but limitations still persist. In this study, we discuss the possibility of using 13 C-13 C dipolar couplings quantified on powdered theophylline at natural isotopic abundance with the help of dynamic nuclear polarization, to realize a DFT-free, rapid screening of a pool of structures predicted by ab initio random structure search. We show that although 13 C-13 C dipolar couplings can identify structures possessing long range structural motifs and unit cell parameters close to those of the true structure, it must be complemented with other data to recover information about the presence and the chemical nature of the supramolecular interactions.

  • Tran, J.; Pesenti, T.; Cressonnier, J.; Lefay, C.; Gigmes, D.; Guillaneuf, Y.; Nicolas, J. Biomacromolecules 2019, 20 (1), 305-317.
    Résumé : 2-Methylene-1,3-dioxepane (MDO) and different vinyl ether (VE) monomers were successfully copolymerized by free-radical radical ring-opening copolymerization (rROP) to yield P(MDO-co-VE) copolymers with M-n = 7 000-13 000 g.mol(-1) and high molar fractions of MDO (F-MDO = 0.7-0.9). By using VE derivatives of different aqueous solubilities or by grafting PEG chains onto the copolymers by "click" chemistry via azide-containing

  • Trimaille, T.; Lacroix, C.; Verrier, B. European Journal of Pharmaceutics and Biopharmaceutics 2019, 142, 232-239.
    Résumé : Subunit vaccines using recombinant antigens appear as the privileged vaccination technology for safety reasons but still require the development of carriers/adjuvants ensuring optimal immunogenicity and efficacy. Micelles from self-assembled amphiphilic copolymers have recently emerged as highly relevant and promising candidates owing to their ease of preparation, low size (entering in lymphatic capillaries for reaching lymph nodes), size/surface tunability and chemical versatility enabling introduction of stimuli (e.g. pH) responsive features and biofunctionalization with dedicated molecules. In particular, research efforts have increasingly focused on dendritic cells (DCs) targeting and activation by co-delivering (with antigen) ligands of pattern recognition receptors (PRRs, e.g. toll-like receptors). Such strategy has appeared as one of the most effective for eliciting CD 8+ T-cell response, which is crucial in the eradication of tumors and numerous infectious diseases. In this short review, we highlight the recent advances in such micelle-based carriers in subunit vaccination and how their precise engineering can be a strong asset for guiding and controlling immune responses.

  • Viger-Gravel, J.; Avalos, C. E.; Kubicki, D. J.; Gajan, D.; Lelli, M.; Ouari, O.; Lesage, A.; Emsley, L. Angewandte Chemie-International Edition 2019, 58 (22), 7249-7253.
    Résumé : The introduction of high-frequency, high-power microwave sources, tailored biradicals, and low-temperature magic angle spinning (MAS) probes has led to a rapid development of hyperpolarization strategies for solids and frozen solutions, leading to large gains in NMR sensitivity. Here, we introduce a protocol for efficient hyperpolarization of F-19 nuclei in MAS DNP enhanced NMR spectroscopy. We identified trifluoroethanol-d(3) as a versatile glassy matrix and show that 12mm AMUPol (with microcrystalline KBr) provides direct F-19 DNP enhancements of over 100 at 9.4T. We applied this protocol to obtain DNP-enhanced F-19 and F-19-C-13 cross-polarization (CP) spectra for an active pharmaceutical ingredient and a fluorinated mesostructured hybrid material, using incipient wetness impregnation, with enhancements of approximately 25 and 10 in the bulk solid, respectively. This strategy is a general and straightforward method for obtaining enhanced F-19 MAS spectra from fluorinated materials.

  • Villotte, S.; Gigmes, D.; Dumur, F.; Lalevee, J. Molecules (Basel, Switzerland) 2019, 25 (1).
    Résumé : Iodonium salts are well established photoacid generators, cationic photoinitiators, as well as additives commonly used in photoredox catalytic cycles. However, as a strong limitation, iodonium salts are characterized by low light absorption properties for lambda > 300 nm so that these latter cannot be activated with cheap, safe, and eco-friendly near UV or even visible light emitting diodes (LEDs). To overcome this drawback, the covalent linkage of an iodonium salt to a chromophore absorbing at longer wavelength is actively researched. With aim at red-shifting the absorption spectrum of the iodonium salt, the synthesis of new compounds combining within a unique chemical structure both the chromophore (here the naphthalimide scaffold) and the iodonium salt is presented. By mean of this strategy, a polymerization could be initiated at 365 nm with the modified iodonium salts whereas no polymerization could be induced with the benchmark iodonium salt i.e., Speedcure 938 at this specific wavelength. To examine the effect of the counter-anion on the photoinitiating ability of these different salts, five different counter-anions were used. Comparison between the different anions revealed the bis(trifluoromethane)sulfonimide salt to exhibit the best photoinitiating ability in both the free radical polymerization of acrylates and the cationic polymerization of epoxides. To support the experimental results, molecular orbital calculations have been carried out. By theoretical calculations, the initiating species resulting from the photocleavage of the iodonium salts could be determined. The cleavage selectivity and the photochemical reactivity of the new iodoniums are also discussed.

  • Vinciguerra, D.; Jacobs, M.; Denis, S.; Mougin, J.; Guillaneuf, Y.; Lazzari, G.; Zhu, C.; Mura, S.; Couvreur, P.; Nicolas, J. Journal of Controlled Release 2019, 295, 223-236.
    Résumé : Well-defined, heterotelechelic polymer prodrugs for combination therapy were synthesized by using a combination of the "drug-initiated" nitroxide-mediated polymerization from a gemcitabine-alkoxyamine initiator and the nitroxide exchange reaction using TEMPO-bearing drugs to end-cap the drug-polymer chain-end by a second drug. This methodology was successfully applied to two different clinically relevant combinations, gemcitabine/doxorubicin (Gem/Dox) and gemcitabine/lapatinib (Gem/Lap), showing a certain degree of universality of the synthetic methodology. It also represented the first nanocarrier for the co-delivery of Gem and Lap ever reported. Well-controlled, low molar mass heterotelechelic polymers (M-n = 2100-4090 g.mol(-1), D = 1.18-1.38) with similar to 1:1 drug ratios and high overall drug loadings up to 40 wt% were obtained. They were formulated into nanoparticles by nanoprecipitation and exhibited average diameters in the 34-154 nm range, with narrow particle size distributions (PSD= 0.01-0.22) and excellent colloidal stability over time. Their biological evaluation in terms of drug release and cytotoxicity was performed and compared to that of different monofunctional polymer prodrug formulations. We showed that heterobifunctional polymer prodrugs induced cytotoxicity to MCF-7 cells, with IC50 values in the 120-300 nM range depending on the combination tested. Interestingly, whereas Gem/Dox combination did not lead to noticeable improvement over monofunctional therapies, co-nanoprecipitation of Gem/Lap prodrugs led to synergistic effect.

  • Vioglio, P. C.; Thureau, P.; Juramy, M.; Ziarelli, F.; Viel, S.; Williams, P. A.; Hughes, C. E.; Harris, K. D. M.; Mollica, G. The journal of physical chemistry letters 2019, 1505-1510.
    Résumé : Crystallization plays an important role in many areas, and to derive a fundamental understanding of crystallization processes, it is essential to understand the sequence of solid phases produced as a function of time. Here, we introduce a new NMR strategy for studying the time evolution of crystallization processes, in which the crystallizing system is quenched rapidly to low temperature at specific time points during crystallization. The crystallized phase present within the resultant "frozen solution" may be investigated in detail using a range of sophisticated NMR techniques. The low temperatures involved allow dynamic nuclear polarization (DNP) to be exploited to enhance the signal intensity in the solid-state NMR measurements, which is advantageous for detection and structural characterization of transient forms that are present only in small quantities. This work opens up the prospect of studying the very early stages of crystallization, at which the amount of solid phase present is intrinsically low.

  • Yamasaki, T.; Buric, D.; Chacon, C.; Audran, G.; Braguer, D.; Marque, S. R. A.; Carre, M.; Bremond, P. Bioorganic & Medicinal Chemistry 2019, 27 (10), 1942-1951.
    Résumé : Previously, we described alkoxyamines bearing a pyridine ring as new pro-drugs with low molecular weights and theranostic activity. Upon chemical stimulus, alkoxyamines undergo homolysis and release free radicals, which can, reportedly, enhance magnetic resonance imaging and trigger cancer cell death. In the present study, we describe the synthesis and the anti-cancer activity of sixteen novel alkoxyamines that contain an imidazole ring. Activation of the homolysis was conducted by protonation and/or methylation. These new molecules displayed cytotoxic activities towards human glioblastoma cell lines, including the U251-MG cells that are highly resistant to the conventional chemotherapeutic agent Temozolomide. We further showed that the biological activities of the alkoxyamines were not only related to their half-life times of homolysis. We lastly identified the alkoxyamine ( RS/SR)-4a, with both a high antitumour activity and favourable logD(7.4) and pK(a) values, which make it a robust candidate for blood-brain barrier penetrating therapeutics against brain neoplasia.

  • Yang, X.; Giorgi, M.; Karoui, H.; Gigmes, D.; Hornebecq, V.; Ouari, O.; Kermagoret, A.; Bardelang, D. Chemical Communications 2019, 55 (92), 13824-13827.
    Résumé : Metal-organic framework (MOF) type crystals in which rigid, viologen-based pillars are surrounded by cucurbit[7]uril (CB[7]) macrocycles are described. These metal-organic rotaxane frameworks (MORF) are obtained by desolvation of a crystal precursor featuring a network already near-optimal toward 3D metal-ligand reticulation and show reversible photochromism.

  • Yin, H.; Cheng, Q.; Rosas, R.; Viel, S.; Monnier, V.; Charles, L.; Siri, D.; Gigmes, D.; Ouari, O.; Wang, R.; Kermagoret, A.; Bardelang, D. Chemistry-a European Journal 2019, 25 (54), 12552-12559.
    Résumé : The capture of pH-responsive guest molecules by CB[8] macrocycles made it possible to produce 2:2 host:guest complexes, releasing protons initially trapped on the guests, in a manner similar to the proton release observed in biology and operating through cascade supramolecular events. More information can be found in the Full Paper by R. Wang, A. Kermagoret, D. Bardelang, et al. (DOI: 10.1002/chem.201902057).

  • Zanolla, D.; Perissutti, B.; Vioglio, P. C.; Chierotti, M. R.; Gigli, L.; Demitri, N.; Passerini, N.; Albertini, B.; Franceschinis, E.; Keiser, J.; Voinovich, D. European Journal of Pharmaceutical Sciences 2019, 140, 105084.
    Résumé : A rotated Doehlert matrix was utilized to explore the experimental design space around the milling parameters of Praziquantel (PZQ) polymorph B formation in terms of frequency and milling time. Three experimental responses were evaluated on the resulting ground samples: two quantitative responses, i.e. median particle size by Laser Light scattering (LLS) and drug recovery by HPLC, and one qualitative dependent variable, i.e. the obtained PZQ crystalline form, characterized through X-Ray Powder Diffraction (XRPD) and confirmed by Differential Scanning Calorimetry (DSC) and Thermogravimetric analysis (TGA). Temperature inside the jars was kept under constant control during the milling process by using temperature sensor equipped jars (thermojars), thus allowing evaluation of the obtained solid states at each experimental point, considering the specific temperature of the process. This explorative analysis led to the finding of a novel PZQ polymorph, named "Form C", produced without degradation, then fully characterized, including by means of Synchrotron XRPD, Polarimetric, FT-IR, SS-NMR, ESEM and saturation solubility. Crystal structure was solved from XRPD data and its geometry was optimized by DFT calculations (CASTEP). Finally, Form C and Form A activity against adult schistosoma mansoni were compared through in vitro testing, and Form C's physical stability checked. The new polymorph, crystallizing in space group I2/c, physically stable for approximately 2 months, showed a m.p. of 106.84 degrees C and displayed excellent biopharmaceutical properties (water solubility of 382.69 +/- 9.26 mg/l), while preserving excellent activity levels against adult schistosoma mansoni.

  • Zhang, T. - S.; Li, Z. - W.; Fang, Q.; Barbatti, M.; Fang, W. - H.; Cui, G. Journal of Physical Chemistry A 2019, 123 (29), 6144-6151.
    Résumé : Herein, we have employed OM2/MRCI-based full-dimensional nonadiabatic dynamics simulations to explore the photoisomerization and subsequent excited-state decay of a macrocyclic cyclobiazobenzene molecule. Two S-1/S-0 conical intersection structures are found to be responsible for the excited-state decay. Related to these two conical intersections, we found two stereoselective photoisomerization and excited-state decay pathways, which correspond to the clockwise and counterclockwise rotation motions with respect to the N=N bond of the azo group. In both pathways, the excited-state isomerization is ultrafast and finishes within ca. 69 fs, but the clockwise isomerization channel is much more favorable than the counterclockwise one with a ratio of 74% versus 26%. Importantly, the present work demonstrates that stereoselective pathways exist not only in the photoisomerization of isolated azobenzene (AB)-like systems but also in macrocyclic systems with multiple ABs. This finding could provide useful insights for understanding and controlling the photodynamics of macrocyclic nanostructures with AB units as the main building units.

  • Zielonka, J.; Zielonka, M.; Cheng, G.; Hardy, M.; Kalyanaraman, B. Methods in molecular biology (Clifton, N.J.) 2019, 1982, 429-446.
    Résumé : Development of new, selective inhibitors of nicotinamide adenine dinucleotide phosphate oxidase (NOX) isoforms is important both for basic studies on the role of these enzymes in cellular redox signaling, cell physiology, and proliferation and for development of new drugs for diseases carrying a component of increased NOX activity, such as several types of cancer and cardiovascular and neurodegenerative diseases. High-throughput screening (HTS) of large libraries of compounds remains the major approach for development of new NOX inhibitors. Here, we describe the protocol for the HTS campaign for NOX inhibitors using rigorous assays for superoxide radical anion and hydrogen peroxide, based on oxidation of hydropropidine, coumarin boronic acid, and Amplex Red. We propose using these three probes to screen for and identify new inhibitors, by selecting positive hits that show inhibitory effects in all three assays. Protocols for the synthesis of hydropropidine and for confirmatory assays, including oxygen consumption measurements, electron paramagnetic resonance spin trapping of superoxide, and simultaneous monitoring of superoxide and hydrogen peroxide, are also provided.

  • Zivic, N.; Kuroishi, P. K.; Dumur, F.; Gigmes, D.; Dove, A. P.; Sardon, H. Angewandte Chemie-International Edition 2019, 58 (31), 10410-10422.
    Résumé : Photopolymerization, or the use of light to trigger polymerization, is one of the most exciting technologies for advanced manufacturing of polymers. One of the key components in the photopolymerization processes is the photoactive compound that absorbs the light, generating the active species that promotes the polymerization and largely determines the final properties of the material. The field of photopolymerization has been dominated by photoradical generators to mediate radical reactions. In the last decade, to expand the number of polymers that can be prepared by photopolymerization, intensive research has been devoted to the synthesis and utilization of photoactive molecules that are able to generate a base or an acid upon irradiation. These organic compounds are known to promote not only the ring-opening polymerization of various heterocyclic monomers such as lactones, carbonates, or epoxides but also to trigger the step-growth synthesis of polyurethanes. This Minireview highlights the recent advances in the development of organic photobase and photoacid generators, with the aim of encouraging the wider application of these photoactive compounds in the photopolymerization area and to expand the use of these polymers in advanced manufacturing processes.