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Productions scientifiques

2016, ICR-2010-2017.

ACL - Articles dans des revues à comité de lecture

85 références.

  • Amalian, J. - A.; Trinh, T. T.; Lutz, J. - F.; Charles, L. Analytical Chemistry 2016, 88 (7), 3715-3722.
    Résumé : Tandem mass spectrometry was evaluated as a reliable sequencing methodology to read codes encrypted in monodisperse sequence-coded oligo(triazole amide)s. The studied oligomers were composed of monomers containing a triazole ring, a short ethylene oxide segment, and an amide group as well as a short alkyl chain (propyl or isobutyl) which defined the 0/1 molecular binary code. Using electrospray ionization, oligo(triazole amide)s were best ionized as protonated molecules and were observed to adopt a single charge state, suggesting that adducted protons were located on every other monomer unit. Upon collisional activation, cleavages of the amide bond and of one ether bond were observed to proceed in each monomer, yielding two sets of complementary product ions. Distribution of protons over the precursor structure was found to remain unchanged upon activation, allowing charge state to be anticipated for product ions in the four series and hence facilitating their assignment for a straightforward characterization of any encoded oligo(triazole amide)s.
    Mots-clés : collision-induced dissociation, containing macromolecules, defined oligomers, electrospray-ionization mass, fragmentation pathways, lithium-attachment ions, poly(alkoxyamine amide)s, synthetic-polymers, tandem mass-spectrometry, time-of-flight.

  • Antol, I.; Glasovac, Z.; Margetic, D.; Crespo-Otero, R.; Barbatti, M. Journal of Physical Chemistry A 2016, 120 (36), 7088-7100.
    Résumé : UV/vis spectra of phenylguanidine (PHGU) in the gas phase and in acetonitrile have been simulated by TD-DFT calculations. Several DFT hybrid and long-range corrected functionals were tested with respect to CASPT2 gas phase calculations. Solvent effects were considered using polarizable continuum model (PCM) and compared with the measured data in acetonitrile. Comparison with isoelectronic phenylurea and related phenyltiourea was done as well. The PBE0 and long-range corrected CAM-B3LYP functionals were selected to investigate the effect of protonation on the excitation energies and absorption intensities of PHGU and several guanidine derivatives with different aromatic chromophoric groups (naphthyl, anthracenyl, quinolinyl, anthraquinonyl, and coumarinyl). Also, the effect of complexation and specific interactions through hydrogen bonds with different anions was examined. It was shown that the protonation of the guanidine subunit shifts the low energy absorption bands toward higher energies (hypsochromic shift). The shift is reduced upon complexation with anions. In phenylguanidine salts, lambda(max) values are correlated to the anion basicity and strength of H-bonding. The observed changes diminish upon increase of chromophoric size (naphthyl, anthracenyl). Theoretical predictions of UV/vis spectra correlate well with experimentally measured spectra of selected guanidine derivatives and their salts.
    Mots-clés : 2nd-order perturbation-theory, abiotic guanidinium, anion recognition, binding, density-functional theory, energy, molecular recognition, program, receptors, thermochemical kinetics.

  • Aquilante, F.; Autschbach, J.; Carlson, R. K.; Chibotaru, L. F.; Delcey, M. G.; De Vico, L.; Galvan, I. F.; Ferre, N.; Frutos, L. M.; Gagliardi, L.; Garavelli, M.; Giussani, A.; Hoyer, C. E.; Li Manni, G.; Lischka, H.; Ma, D.; Malmqvist, P. A.; Mueller, T.; Nenov, A.; Olivucci, M.; Pedersen, T. B.; Peng, D.; Plasser, F.; Pritchard, B.; Reiher, M.; Rivalta, I.; Schapiro, I.; Segarra-Marti, J.; Stenrup, M.; Truhlar, D. G.; Ungur, L.; Valentini, A.; Vancoillie, S.; Veryazov, V.; Vysotskiy, V. P.; Weingart, O.; Zapata, F.; Lindh, R. Journal of Computational Chemistry 2016, 37 (5), 506-541.
    Résumé : In this report, we summarize and describe the recent unique updates and additions to the Molcas quantum chemistry program suite as contained in release version 8. These updates include natural and spin orbitals for studies of magnetic properties, local and linear scaling methods for the Douglas-Kroll-Hess transformation, the generalized active space concept in MCSCF methods, a combination of multiconfigurational wave functions with density functional theory in the MC-PDFT method, additional methods for computation of magnetic properties, methods for diabatization, analytical gradients of state average complete active space SCF in association with density fitting, methods for constrained fragment optimization, large-scale parallel multireference configuration interaction including analytic gradients via the interface to the Columbus package, and approximations of the CASPT2 method to be used for computations of large systems. In addition, the report includes the description of a computational machinery for nonlinear optical spectroscopy through an interface to the QM/MM package Cobramm. Further, a module to run molecular dynamics simulations is added, two surface hopping algorithms are included to enable nonadiabatic calculations, and the DQ method for diabatization is added. Finally, we report on the subject of improvements with respects to alternative file options and parallelization. (c) 2015 Wiley Periodicals, Inc.
    Mots-clés : 2-dimensional electronic spectroscopy, 2nd-order perturbation-theory, auxiliary basis-sets, density-functional theory, direct configuration-interaction, electron correlation, field reference functions, gradients, molecular dynamics, multiple active spaces, parallelization, relativistic, retinal chromophore model, single-molecule magnet, transition-metal atoms.

  • Arbelo-Gonzalez, W.; Crespo-Otero, R.; Barbatti, M. Journal of Chemical Theory and Computation 2016, 12 (10), 5037-5049.
    Résumé : Semiclassical methods to simulate both steady and time-resolved photoelectron spectra are presented. These approaches provide spectra with absolute band shapes and vibrational broadening beyond the Condon approximation, using an ensemble of nuclear configurations built either via distribution samplings or nonadiabatic dynamics simulations. Two models to account for the electron kinetic energy modulation due to vibrational overlaps between initial and final states are discussed. As illustrative examples, the steady photoelectron spectra of imidazole and adenine and the time and kinetic-energy-resolved photoelectron spectrum of imidazole were simulated within the frame of time-dependent density functional theory. While for steady spectra only electrons ejected with maximum allowed kinetic energy need to be considered, it is shown that to properly describe time-resolved spectra, electrons ejected with low kinetic energies must be considered in the simulations as well. The results also show that simulations based either on full computation of photoelectron cross section or on simple Dyson orbital norms provide results of similar quality.
    Mots-clés : density-functional theory, electronic-structure, excited-state dynamics, identity approximation, ionization-potentials, molecular-dynamics, nonadiabatic dynamics, polarization propagator, ultraviolet photoelectron, vibrational dynamics.

  • Auberger, N.; Stanovych, A.; Thétiot-Laurent, S.; Guillot, R.; Kouklovsky, C.; Cote des Combes, S.; Pacaud, C.; Devillers, I.; Alezra, V. Amino Acids 2016, 48 (9), 2237-2242.

  • Audran, G.; Bagryanskaya, E. G.; Bremond, P.; Edeleva, M. V.; Marque, S. R. A.; Parkhomenko, D. A.; Rogozhnikova, O. Y.; Tormyshev, V. M.; Tretyakov, E. V.; Trukhin, D. V.; Zhivetyeva, S. I. Polymer Chemistry 2016, 7 (42), 6490-6499.
    Résumé : Recently, new applications of trityl-nitroxide biradicals were proposed. In the present study, attachment of a trityl radical to alkoxyamines was performed for the first time. The rate constants k(d) of C-ON bond homolysis in these alkoxyamines were measured and found to be similar to those for alkoxyamines without a trityl moiety. The electron paramagnetic resonance (EPR) spectra of the products of alkoxyamine homolysis (trityl-TEMPO and trityl-SG1 biradicals) were recorded, and the corresponding exchange interactions were estimated. The decomposition of trityl-alkoxyamines showed more than an 80% yield of biradicals, meaning that the C-ON bond homolysis is the main reaction. The suitability of these labelled initiators/controllers for polymerisation was exemplified by means of a successful nitroxide-mediated polymerisation (NMP) of styrene. Thus, this is the first report of a spin-labelled alkoxyamine suitable for NMP.
    Mots-clés : dynamic nuclear-polarization, epr, fragment, labile alkoxyamines, Nitroxide-mediated polymerization, on bond homolysis, oxygen, radical polymerization, rate-constant, sensitivity.

  • Audran, G.; Bagryanskaya, E.; Bagryanskaya, I.; Bremond, P.; Edeleva, M.; Marque, S. R. A.; Parkhomenko, D.; Tretyakov, E.; Zhivetyeva, S. Inorganic Chemistry Frontiers 2016, 3 (11), 1464-1472.
    Résumé : The metal complexation reactions of bis(hexafluoroacetylacetonato)copper(II)(Cu(hfac)(2)) with alkoxyamines (diethyl(2,2-dimethyl-1-(tert-butyl-(1-(pyridine-4-yl)ethoxy)amino)propyl)phosphonate and diethyl (2,2-dimethyl-1-(tert-butyl-(1-(pyridine-2-yl)ethoxy)amino)propyl)phosphonate) were studied. According to X-ray analysis, the molecular and crystal structures of 1:1 complexes depend on the configuration of the free alkoxyamines, that is dimeric (RSSR) and chain-polymeric (RR/SS) structures for para-pyridyl-substituted alkoxyamines, and cyclic unimeric (RS/SR) structure for ortho-pyridyl derivative. The complex (2:1 ratio Cu(hfac)(2)/alkoxyamine) for ortho-pyridyl-substituted alkoxyamine is not resolved. Upon warming, ortho complexes decomposed into free alkoxyamines and only a weak activation was observed. Upon warming, para complexes decomposed into their corresponding unimers, and then, a 21-fold increase in the rate constant of the C-ON bond homolysis was observed compared to the corresponding free alkoxyamines. Tuning of the homolysis rate constant of the C-ON bond via addition of pyridine is also reported.
    Mots-clés : adducts, cancer, crystal, family, fragment, Nitroxide-mediated polymerization, polymers, theranostic agents.

  • Audran, G.; Bosco, L.; Bremond, P.; Butscher, T.; Franconi, J. - M.; Kabitaev, K.; Marque, S. R. A.; Mellet, P.; Parzy, E.; Santelli, M.; Thiaudiere, E.; Viel, S. Rsc Advances 2016, 6 (7), 5653-5670.
    Résumé : Recently, we published the titration of water in organic solvents and conversely using this family of nitroxides (Org. Biomol. Chem. 2015 ASAP). In this article, we show that the a(beta,P) of persistent cyclic beta-phosphorylated nitroxides decreases with the normalized polarity Reichardt's constant E-T(N). Koppel-Palm and Kalmet-Abboud-Taft relationships were applied to get a deeper insight into the effects influencing a(N) and a(beta,P): polarity/polarizability, hydrogen bond donor property, and structuredness of the cybotactic region.
    Mots-clés : aminoxyl radicals, bond homolysis, epr, esr, mri, nitrogen, polarity, probes, resonance, ring nitroxides.

  • Audran, G.; Bosco, L.; Bremond, P.; Butscher, T.; Marque, S. R. A. Organic & Biomolecular Chemistry 2016, 14 (4), 1288-1292.
    Résumé : For decades, the nitrogene hyperfine coupling constant a(N) of nitroxides has been applied to probe their environment using EPR. However, the small changes observed (approximate to 2 G from n-pentane to water) with the solvent polarity allow only a qualitative discussion. A stable beta-phosphorylated nitroxide exhibiting a small change in a(N) (approximate to 3 G from n-pentane to water) and a striking change (approximate to 25 G from n-pentane to water) in phosphorus hyperfine coupling constant a(P) with the polarity of solvent was prepared and used to develop the first procedure for the titration of water in THF by EPR, down to 0.1% v/v.
    Mots-clés : aminoxyl radicals, constants, epr, esr, mixtures, nitrogen, polarity, preferential solvation, probe, solute-solvent.

  • Audran, G.; Bosco, L.; Bremond, P.; Butscher, T.; Marque, S. R. A.; Viel, S. Chemphyschem 2016, 17 (23), 3954-3963.
    Résumé : Recently, we reported a dramatic solvent effect on the phosphorus hyperfine coupling constant a(P) of beta-phosphorylated six-membered ring nitroxides, that is, a(P)proximately 25G of difference in a(P) from n-hexane to water (Org. Biomol. Chem. 2016, 14, -1228-1292). In this article, we report on the effect of intramolecular hydrogen bonding (IHB) in three nitroxides exhibiting IHB between the hydroxyl and diethylphosphoryl groups and one exhibiting IHB between the hydroxyl group and the nitroxyl moiety. It is observed that for the first three nitroxides, a(P) increases with increasing polarity/polarizability and hydrogen bond donor (HBD) properties of the solvent (pi* and alpha, respectively)-in sharp contrast to the data reported in the literature-and for the last nitroxide, a(P) decreases with pi* and alpha. In fact, the occurrence of IHB induces a large strain, its suppression by hydrogen bond acceptor (HBA) solvents affords an increase in a(P).
    Mots-clés : Alkoxyamines, aminoxyl radicals, electron-paramagnetic-resonance, EPR spectroscopy, esr, fragment, homolysis rate-constant, hydrogen bonds, multiparameter analysis, nitrogen, nitroxides, polarity, probes, radical polymerization, solvent effect.

  • Audran, G.; Bosco, L.; Nkolo, P.; Bikanga, R.; Bremond, P.; Butscher, T.; Marque, S. R. A. Organic & Biomolecular Chemistry 2016, 14 (15), 3729-3743.
    Résumé : In two recent articles (Org. Biomol. Chem., 2015 and 2016), we showed that changes in the phosphorus hyperfine coupling constant a(P) at position beta in beta-phosphorylated nitroxides can be dramatic. Such changes were applied to the titration of water in organic solvents and conversely of organic solvents in water. One of the molecules tested was a non-cyclic nitroxide meaning that a thorough investigation of the solvent effect on the EPR hyperfine coupling constant is timely due. In this article, we show that the aP of persistent non-cyclic beta-phosphorylated nitroxides decrease with the normalized polarity Reichardt's constant ENT. The Koppel-Palm and Kalmet-Abboud-Taft relationships were applied to gain deeper insight into the effects influencing a(N) and a(P): polarity/polarizability, hydrogen bond donor properties, and the structuredness of the cybotactic region.
    Mots-clés : Alkoxyamine, electron-paramagnetic-resonance, homolysis, nitrogen, polarity, probes, radicals.

  • Audran, G.; Bremond, P.; Joly, J. - P.; Marque, S. R. A.; Yamasaki, T. Organic & Biomolecular Chemistry 2016, 14 (14), 3574-3583.
    Résumé : The application of alkoxyamines as initiators/controllers in nitroxide mediated polymerization and as agents for theranostics requires the development of switchable (from stable one to labile one) alkoxyamines. One way to achieve this is to tune the polarity of various groups carried by either the alkyl fragment or the nitroxyl fragment. Thus, the effect of protonation/deprotonation of the para-functionalized aryl moiety carried by the alkyl fragment in diethyl(2,2-dimethyl-1-((1,1-dimethylethyl)(1-para-subsituted-phenyletho xy) amino) propyl) phosphonate is investigated. An increase in k(d) is observed with increasing localized electrical effect, i.e., in the presence of electron withdrawing groups at the para position of the phenyl ring. A striking effect of the intimate ion pair on kd is also observed.
    Mots-clés : benzyl radicals, constants, methylenecyclopropane rearrangement, Nitroxide, polar, Polymerization, radical stabilization energies, sg1-based alkoxyamines, spin-delocalization, values.

  • Audran, G.; Bremond, P.; Marque, S. R. A.; Santelli, M. Tetrahedron Letters 2016, 57 (50), 5703-5706.
    Résumé : The dehydrodimerization of 2-butanone or 3-pentanone by lead dioxide leads to 3,4-dimethyl-2,5-hexanedione or 4,5-dimethyl-3,6-octanedione in nearly quantitative yield. This very clean and efficient reaction has been studied from mechanistic and stereochemical points of view. Dehydrodimerization of a 1:1 molar mixture of 2-butanone and 3-pentanone leads to 3,4-dimethyl-2,4-heptanedione in similar to 50% yield. From these gamma-diketones, 2,3,4-trimethylcyclopentenone, 3,4,5-trimethylcyclopentenone, 2,3,4,5-tetramethylcyclopentenone or 3-ethyl-2,4,5-trimethylcyclopentenone were obtained. (C) 2016 Elsevier Ltd. All rights reserved.
    Mots-clés : 1,2,3,4,5-pentamethylcyclopentadiene, 1,4-diketones, Acyl radical, carboxylic-acids, coupling reaction, Cyclization, Dehydrodimerization, gamma-Diketones, ketone, Lead dioxide, Photochemistry, stereochemistry, trimethylsilyl enol ethers.

  • Audran, G.; Bremond, P.; Marque, S. R. A.; Siri, D.; Santelli, M. Tetrahedron Letters 2016, 57 (16), 1743-1749.
    Résumé : As the well known protonated cyclopropanes' present calculations confirm the existence of acetylated cyclopropanes, we describe the structure of edge- and corner-acetylated cyclopropanes rising from the energetically favored addition of acetyl cation to cyclopropanes. Some of those explain the few available experimental results concerning the acetylation reaction of cyclopropanes. Structures have been calculated at the B3LYP/6-311++G(3df,3pd) and MP2/6-311++G(3df,3pd) levels of theory in ideal gas and in dichloromethane as solvent. Transition state geometries in ideal gas and in dichloromethane as solvent were confirmed by intrinsic reaction coordinate (IRC) calculations. (C) 2016 Elsevier Ltd. All rights reserved.
    Mots-clés : ab-initio, Acetylated cyclopropanes, acid, Acylation, biosynthesis, carbonium, cation, chemistry, Cyclopropanes, Intrinsic reaction coordinate (IRC) calculations, nonclassical carbocations, protonated cyclopropane, rearrangements, solvolytic reactions, Transition state.

  • Audran, G.; Bremond, P.; Marque, S. R. A.; Yamasaki, T. Journal of Organic Chemistry 2016, 81 (5), 1981-1988.
    Résumé : A few years ago, Bagryanskaya and colleagues (J. Org. Chem. 2011) showed that protonation of the nitroxyl fragment deactivated the alkoxyamine C-ON bond. Conversely, our group showed that protonation (Chem. Commun. 2011), as well as other chemical reactions such as oxidation or amine quaternization (Org. Lett. 2012), of the pyridyl moiety carried by the alkyl fragment was suitable to activate the homolysis of the C-ON bond. To pursue our goal of applying alkoxyamines as theranostic agents (Org. Biomol. Chem. 2014 and Mol. Pharmaceutics 2014) by activation of the C-ON bond homolysis, we turned our interest to the chemical activation of the nitroxyl fragment by oxidation/reduction of selected functions. Conversion of a hydroxyl group located close to the nitroxyl moiety successively into aldehyde, then acid, and eventually into ester, led to a successive decrease in k(d).
    Mots-clés : family, oxidation, radical polymerization.

  • Ay, E.; Raad, Z.; Dautel, O.; Dumur, F.; Wantz, G.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Macromolecules 2016, 49 (6), 2124-2134.
    Résumé : In the present paper, four fluorescent materials currently used in organic light emitting diodes (OLEDs) are presented in an original way as high performance photocatalysts usable in polymerization photoinitiating systems. Their performance is excellent in free radical polymerization, cationic polymerization but also in the synthesis of interpenetrating polymer networks (IPNs). A coherent picture of the chemical mechanisms involved in these new photo catalytic systems is provided. Remarkably, an oligomeric and copolymerizable photocatalyst (PVD2) is proposed here for the first time, i.e., both the high molecular weight of PVD2 and the presence of reactive double bonds as end groups (which could be involved in a copolymerization reaction) ensure a very low migration of the catalyst from the synthesized polymer.

  • Ayari-Riabi, S.; Trimaille, T.; Mabrouk, K.; Bertin, D.; Gigmes, D.; Benlasfar, Z.; Zaghmi, A.; Bouhaouala-Zahar, B.; Elayeb, M. Vaccine 2016, 34 (15), 1810-1815.
    Résumé : Scorpion envenoming represents a public health issue in subtropical regions of the world. Treatment and prevention need to promote antitoxin immunity. Preserving antigenic presentation while removing toxin effect remains a major challenge in toxin vaccine development. Among particulate adjuvant, particles prepared with poly (D,L-lactide) polymer are the most extensively investigated due to their excellent biocompatibility and biodegradability. The aim of this study is to develop surfactant-free PLA nanoparticles that safely deliver venom toxic fraction to enhance specific immune response. PLA nanoparticles are coated with AahG50 (AahG50/PLA) and BotG50 (BotG50/PLA): a toxic fraction purified from Androctonus australis hector and Buthus occitanus tunetanus venoms, respectively. Residual toxicities are evaluated following injections of PLA-containing high doses of AahG50 (or BotG50). Immunization trials are performed with the detoxified fraction administered alone without adjuvant. A comparative study of the effect of Freund is also included. The neutralizing capacity of sera is determined in naive mice. Six months later, immunized mice are challenged subcutaneously with increased doses of AahG50. Subcutaneous lethal dose 50 (LD50) of AahG50 and BotG50 is of 575 mu g/kg and 1300 mu g/kg respectively. By comparison, BotG50/PLA is totally innocuous while 50% of tested mice survive 2875 mu g AahG50/kg. Alhydrogel and Freund are not able to detoxify such a high dose. Cross-antigenicity between particulate and soluble fraction is also, ensured. AahG50/PLA and BotG50/PLA induce high antibody levels in mice serum. The neutralizing capacity per mL of anti-venom was 258 mu g/mL and 186 mu g/mL calculated for anti-AahG50/PLA and anti-BotG50/PLA sera, respectively. Animals immunized with AahG50/PLA are protected against AahG50 injected dose of 3162 mu g/kg as opposed all non-immunized mice died at this dose. We find that the detoxification approach based PLA nanoparticles, benefit the immunogenicity and protective efficacy of venom immunogen. (C) 2016 Elsevier Ltd. All rights reserved.
    Mots-clés : adjuvants, alpha-toxins, antigenicity, Detoxification, immunogenicity, Immunoprotection, Neutralization, PLA nanoparticles, protection, Toxic venom fraction.

  • Bai, S.; Barbatti, M. Journal of Physical Chemistry A 2016, 120 (32), 6342-6350.
    Résumé : Recent experiments replacing oxygen atoms by sulfur in thymine have revealed that absorption and intersystem crossing properties of these derivatives are strongly dependent on the position and number of the substitutions, affecting their potential performance for photodynamical therapy. Using multireference quantum chemical methods (CASPT2 and DFT/MRCI), we calculated absorption spectra and spin orbit coupling matrix elements for thymine (Thy), 2-thiothymine (2tThy), 4-thiothymine (4tThy), and 2,4-dithiothymine (2,4dtThy), to investigate this relation between structure and photophysics. The simulations showed that a simple 4-electrons/4-orbital minimum model can explain the main experimentally observed spectral features. Moreover, the computational estimate of intersystem crossing lifetimes in this sequence of molecules revealed that the experimental value attributed to thymine in water might be underestimated by a factor 20, most probably due to an overlap of singlet/triplet absorption signals in the transient absorption spectrum. The difference between the absorptivity of 2tThy and 2tThd was also investigated, but no conclusive explanation could be found.
    Mots-clés : 2,4-dithiothymine, 4-thiothymidine, 6-aza-2-thiothymine, basis-sets, density-functional theory, DNA, excited-state dynamics, orbital methods, photosensitization, triplet-state.

  • Barbatti, M.; Sen, K. International Journal of Quantum Chemistry 2016, 116 (10), 762-771.
    Résumé : Semiclassical simulations of spectrum and dynamics of complex molecules require statistical sampling of coordinates and momenta. The effects of using thermal and quantum samplings are analyzed taking pyrrole as a test case. It is shown that there are significant differences in the results obtained with each of these two approaches. Overall, quantum sampling based on a Wigner distribution renders superior results, comparing well to the experiments. Dynamics simulations based on surface hopping and ADC(2) reveal that pyrrole internal conversion to the ground state occurs not only through H-elimination path, but also through ring-distortion paths, which have been systematically neglected by diverse experimental setups. The analysis of the reaction paths also shows that the ionization potential varies by more than 5 eV between ionization of the excited state at the Franck-Condon region and at the intersections with the ground state. This feature may have major implications for time-resolved photoelectron spectroscopy. (c) 2015 Wiley Periodicals, Inc.
    Mots-clés : conical intersections, dynamics simulations, electronic-spectrum, excited-state dynamics, general force-field, identity approximation, initial conditions, molecular-dynamics, nonadiabatic dynamics, perturbation-theory, Photochemistry, photodissociation dynamics, polarization propagator, pyrrole, spectrum simulations.

  • Benchekroun, M.; Romero, A.; Egea, J.; Leon, R.; Michalska, P.; Buendia, I.; Jimeno, M. L.; Jun, D.; Janockova, J.; Sepsova, V.; Soukup, O.; Bautista-Aguilera, O. M.; Refouvelet, B.; Ouari, O.; Marco-Contelles, J.; Ismaili, L. Journal of Medicinal Chemistry 2016, 59 (21), 9967-9973.
    Résumé : Novel multifunctional tacrines for Alzheimer's disease were obtained by Ugi-reaction between ferulic (or lipoic acid), a melatonin-like isocyanide, formaldehyde, and tacrine derivatives, according to the antioxidant additive approach in order to modulate the oxidative stress as therapeutic strategy. Compound 5c has been identified as a promising permeable agent showing excellent antioxidant properties, strong cholinesterase inhibitory activity, less hepatotoxicity than tacrine, and the best neuroprotective capacity, being able to significantly activate the Nrf2 transcriptional pathway.
    Mots-clés : acetylcholinesterase, ache inhibitors, derivatives, design, drug candidates, heterodimers, hybrids, hypothesis, mechanisms, neurodegenerative diseases.

  • Besson, E.; Ziarelli, F.; Bloch, E.; Gerbaud, G.; Queyroy, S.; Viel, S.; Gastaldi, S. Chemical Communications 2016, 52 (32), 5531-5533.
    Résumé : Hybrid mesoporous silica materials with wall-embedded nitroxides are shown to efficiently polarize impregnated substrates in high-field dynamic nuclear polarization magic-angle spinning solid-state NMR experiments.
    Mots-clés : solids, spectroscopy.

  • Borie, C.; Ackermann, L.; Nechab, M. Chemical Society Reviews 2016, 45 (5), 1368-1386.
    Résumé : The indanyl core is ubiquitous in a large variety of drugs and natural products. Importantly, the ever-increasing demand for chiral catalysts bearing this scaffold calls for state of the art methods allowing for a step-economical enantioselective access to this structural motif. We herein summarize the asymmetric syntheses of indanes with a particular focus on asymmetric catalysis, covering the literature of the last decade until July 2015.
    Mots-clés : beta-keto-esters, bond-forming reactions, chiral 3-substituted indanones, conjugate addition, hypervalent iodine reagents, insertion reactions, kinetic asymmetric transformations, one-pot synthesis, quaternary stereocenters, reductive-heck reaction.

  • Borie, C.; Vanthuyne, N.; Bertrand, M. P.; Siri, D.; Nechab, M. Acs Catalysis 2016, 6 (3), 1559-1564.
    Résumé : The conversion of propargylic carbonates into allenes via Pd-catalyzed coupling with arylboronic acids, followed by tandem intramolecular Alder-ene cyclization, proceeds with remote diastereocontrol in the formation of indenes possessing two stereogenic elements (stereocenter and chiral axis). Highly configurationally stable atropisomers have been obtained with dr values up to >98:2. The reaction tolerates a range of commercially available functionalized arylboronic acids and allows the creation of C(sp(2))-C(sp(2)) and C(sp(2))-C(sp(3)) bonds in a single operation. Control experiments suggest that synergetic thermal and Pd-catalyzed cyclizations are likely to be involved in the second elementary step.
    Mots-clés : Alder-ene, alder-ene reaction, allenes, atropisomers, bond formation, boronic acids, cascade, cascade rearrangements, coupling reaction, Cyclization, enantioselective synthesis, ene-allenes, indenes, organic-synthesis, oxidative carbocyclization, palladium catalysis, propargylic alcohols, remote diastereocontrol.

  • Broggi, J.; Rollet, M.; Clement, J. - L.; Canard, G.; Terme, T.; Gigmes, D.; Vanelle, P. Angewandte Chemie-International Edition 2016, 55 (20), 5994-5999.
    Résumé : Polymerization reactions with organic electron donors (OED) as initiators are presented herein. The metal-free polymerization of various activated alkene and cyclic ester monomers was performed in short reaction times, under mild conditions, with small amounts of organic reducing agents, and without the need for co-initiators or activation by photochemical, electrochemical, or other methods. Hence, OED initiators enabled the development of an efficient, rapid, room-temperature process that meets the technical standards expected for industrial processes, such as energy savings, cost-effectiveness and safety. Mechanistic investigations support an electron-transfer initiation pathway that leads to the reduction of the monomer.
    Mots-clés : 2-electron transfer, anionic-polymerization, carbanionic polymerization, chain-growth polymerization, electron transfer, free-radical polymerization, methyl-methacrylate, n-heterocyclic carbenes, organic electron donors, reaction mechanisms, reduction, ring-opening polymerization, single-electron, tetraazafulvalene.

  • Cassien, M.; Petrocchi, C.; Thétiot-Laurent, S.; Robin, M.; Ricquebourg, E.; Kandouli, C.; Asteian, A.; Rockenbauer, A.; Mercier, A.; Culcasi, M.; Pietri, S. European Journal of Medicinal Chemistry 2016, 119, 197-217.
    Mots-clés : Antioxidant, antioxidant activity, Aortic rings relaxation, beta-Diethoxyphosphoryl nitrones, butylnitrone pbn, endothelial-cells, EPR spin trapping, functional theory approach, nitric-oxide release, NO donors, Phenolic acids, protective action, reperfusion injury, superoxide spin adducts, tert-butyl nitrone, xanthine-oxidase.

  • Castera-Ducros, C.; El-Kashef, H.; Piednoel, M.; Remusat, V.; Teulade, J. - C.; Verhaeghe, P.; Rathelot, P.; Vanelle, P. Letters in Organic Chemistry 2016, 13 (7), 519-525.
    Résumé : Background:The imidazo[1,2-alpha] pyridine ring has been widely studied by medicinal chemists and displays great pharmaceutical potential. Methods: In a view to prepare a library of new molecules including an imidazo[1,2-alpha] pyridine scaffold, as original fragments for the conception of novel anti-protozoal compounds, the Sonogashira crosscoupling reaction between 3-halogenoimidazo [1,2-alpha] pyridines and phenylacetylene was studied. Results: From 3-iodoimidazo[1,2-alpha] pyridine, chosen as an optimal substrate for conducting the reaction at room temperature in 2 hours, a variety of terminal alkynes was involved into the reaction, leading to a series of 16 new 3-phenyethynylimidazo [1,2-alpha] pyridines in satisfying to good yields (50-82%) and 4 additional derivatives in moderate yields (30-40%). Conclusion: Such synthetic approach appears efficient for the rapid synthesis of imidazopyridine chemical libraries. The corresponding derivatives will next be evaluated for their anti-infective properties.
    Mots-clés : 3-alkynylimidazoimidazo[1,2-alpha]pyridine, 3-halogenoimidazo[1,2-alpha]pyridines, agents, analogs, aqueous-medium, benzodiazepine-receptors, beta-amyloid plaques, cross-coupling reactions, derivatives, discovery, ligands, series, Sonogashira cross-coupling reaction.

  • Cavallo, G.; Al Ouahabi, A.; Oswald, L.; Charles, L.; Lutz, J. - F. Journal of the American Chemical Society 2016, 138 (30), 9417-9420.
    Résumé : A new orthogonal solid-phase iterative strategy is proposed for the synthesis of sequence-coded polymers. This approach relies on the use of two successive chemoselective steps: (i) phosphoramidite coupling, and (ii) radical radical coupling. These repeated steps can be performed using two different types of building blocks, i.e. a phosphoramidite monomer that also contains an alkyl bromide and a hydroxy-functionalized nitroxide. The phosphoramidite and the hydroxy group are reacted in step (i), thus leading to a phosphite that is oxidized in situ into a phosphate bond. The alkyl bromide is activated by copper bromide in step (ii) to afford a carbon-centered radical that is spin-trapped in situ by the nitroxide. The iterative repetition of these steps allow synthesis of uniform polymers, as evidenced by high resolution electrospray mass spectrometry. Moreover, binary information could be easily implemented in the polymers using different types of phosphoramidite monomers in step (i). Interestingly, it was found that the formed information-containing polymers are very easy to sequence by tandem mass spectrometry due to the presence of easily cleavable alkoxyamine bonds formed in step (ii).
    Mots-clés : block, chemistry, DNA, efficient, encoded polymers, macromolecules, sequence-defined oligomers, solid-phase synthesis.

  • Charles, L.; Laure, C.; Lutz, J. - F.; Roy, R. K. Rapid Communications in Mass Spectrometry 2016, 30 (1), 22-28.
    Résumé : RationaleDigitally encoded oligomers composed of two distinct amide coding units spaced by a nitroxide moiety were recently decrypted using a tandem mass spectrometry (MS/MS) sequencing approach developed for protonated oligomers. Here, the MS/MS behavior of deprotonated oligomers was explored in the negative ion mode to provide both structural and mechanistic complementary information. MethodsBinary-encoded oligo(alkoxyamine)amides, containing coding 0/1 amide units spaced by a TEMPO nitroxide moiety, were ionized in negative ion mode electrospray thanks to their end-group containing a carboxylic acid function. Deprotonated molecules were subjected to collision-induced dissociation in MS/MS and MS3 experiments, combined with accurate mass measurements, for a thorough investigation of their dissociation behavior. ResultsDeprotonated oligomers readily dissociated upon collisional activation via competitive homolytic cleavages of all fragile alkoxyamine linkages between any coding 0 or 1 monomers and a nitroxide moiety. As expected, only product ions holding the deprotonated end-group were detected while complementary moieties containing the termination were released as radicals. The so-formed distonic radical anions were observed to further depolymerize according to a radical-induced process, as evidenced by MS3 experiments. ConclusionsMessages encoded in oligo(alkoxyamine)amides were readily decrypted by MS/MS sequencing performed in the negative ion mode. When compared with results obtained in positive ion mode ESI-MS/MS, these data provided further evidence regarding the influence of adducted proton on the charge-remote homolytic cleavage of alkoxyamine linkages. Copyright (c) 2015 John Wiley & Sons, Ltd.

  • Chendo, C.; Le, D.; Phan, T. N. T.; Gigmes, D.; Charles, L. Journal of Polymer Science Part a-Polymer Chemistry 2016, 54 (20), 3388-3397.
    Résumé : An analytical workflow involving high resolution mass analysis, collision-induced dissociation and ion mobility was implemented to structurally characterize polymeric by-products detected in lieu of intact species when performing matrix-assisted laser desorption/ionization (MALDI) of polystyrenes with fragile end groups. Studied samples were prepared by atom transfer radical polymerization, reversible addition-fragmentation transfer polymerization and nitroxide-mediated polymerization. Spectral resolution enabled by orthogonal injection of MALDI ions into a reflectron time-of-flight mass analyzer allowed a thorough inventory of species, including some with the same nominal m/z value but different elemental composition. Individual end-group mass determination was achieved in MS/MS experiments, implementing an additional separative dimension based on ion mobility prior to CID to assist precursor ion selection in case of interferences. Besides validating commonly reported polystyrene chains terminated with either endo- or exo-double bond, this multidimensional approach permitted to show that initiating moiety could also be affected by the MALDI process. (c) 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 3388-3397
    Mots-clés : atrp, capped polystyrene, Controlled radical polymerization, easy access, end-groups, initiators, ion mobility, liquid-chromatography, maldi-ms, mo(iii)/mo(iv), oxide)/polystyrene block-copolymer, Polystyrene, styrene, synthetic-polymers, tandem mass spectrometry.

  • Chendo, C.; Phan, T. N. T.; Marque, S. R. A.; Gigmes, D.; Charles, L. International Journal of Mass Spectrometry 2016, 405, 50-58.
    Résumé : Reactive MALDI was evidenced to occur when using acidic matrices to assist ionization of poly(4-vinylpyridine) (P4VP) prepared by nitroxide mediated polymerization (NMP). The high accessibility of nitrogen atoms in each 4VP units would allow strong hydrogen bonding with acidic matrix molecules, which was shown to further weaken the fragile C-ON linkage between the last monomeric unit and the nitroxide end-group. As a result, release of the nitroxide upon laser irradiation of the MALDI sample would lead to radical chains capable of reacting with the matrix molecule in interaction with the last 4VP unit, yielding a new polymeric by-product where one matrix molecule is incorporated in the chain termination. The mechanism proposed for this reaction was supported by accurate mass measurements, MS/MS data as well as electron paramagnetic resonance (EPR) experiments. Interestingly, such matrix/polymer covalent adducts were no longer observed when using MALDI source operated at high vacuum. (C) 2016 Elsevier B.V. All rights reserved.
    Mots-clés : assisted-laser-desorption/ionization, Covalent matrix adduct, dynamics model, free sample preparation, ionization, labile end-groups, Mass spectrometry, matrix, mechanism, on bond homolysis, P4VP, Poly(4-vinylpyridine), Reactive MALDI, sinapinic acid, Synthetic polymer, tof ms.

  • Cheng, G.; Zielonka, J.; Ouari, O.; Lopez, M.; McAllister, D.; Boyle, K.; Barrios, C. S.; Weber, J. J.; Johnson, B. D.; Hardy, M.; Dwinell, M. B.; Kalyanaraman, B. Cancer Research 2016, 76 (13), 3904-3915.
    Résumé : Metformin (Met) is an approved antidiabetic drug currently being explored for repurposing in cancer treatment based on recent evidence of its apparent chemopreventive properties. Met is weakly cationic and targets the mitochondria to induce cytotoxic effects in tumor cells, albeit not very effectively. We hypothesized that increasing its mitochondria-targeting potential by attaching a positively charged lipophilic substituent would enhance the antitumor activity of Met. In pursuit of this question, we synthesized a set of mitochondria-targeted Met analogues (Mito-Mets) with varying alkyl chain lengths containing a triphenylphosphonium cation (TPP+). In particular, the analogue Mito-Met(10), synthesized by attaching TPP+ to Met via a 10-carbon aliphatic side chain, was nearly 1,000 times more efficacious than Met at inhibiting cell proliferation in pancreatic ductal adenocarcinoma (PDAC). Notably, in PDAC cells, Mito-Met(10) potently inhibited mitochondrial complex I, stimulating superoxide and AMPK activation, but had no effect in nontransformed control cells. Moreover, Mito-Met(10) potently triggered G(1) cell-cycle phase arrest in PDAC cells, enhanced their radiosensitivity, and more potently abrogated PDAC growth in preclinical mouse models, compared with Met. Collectively, our findings show how improving the mitochondrial targeting of Met enhances its anticancer activities, including aggressive cancers like PDAC in great need of more effective therapeutic options. (C) 2016 AACR.
    Mots-clés : bioenergetics, breast-cancer, death, generation, ionizing-radiation, kinase ampk, lung-cancer, metabolism, proliferation, survival.
  • Da Costa, L.; Roche, M.; Scheers, E.; Coluccia, A.; Neyts, J.; Terme, T.; Leyssen, P.; Silvestri, R.; Vanelle, P. European Journal of Medicinal Chemistry 2016, 115, 453-462.
    Résumé : Human rhinoviruses (HRV) are the predominant cause of common colds and flu-like illnesses, but are also responsible for virus-induced exacerbations of asthma and chronic obstructive pulmonary disease. However, to date, no drug has been approved yet for clinical use. In this study, we present the results of the structure-based lead optimization of a class of new small-molecule inhibitors that we previously reported to bind into the pocket beneath the canyon of the VP1 protein. A small series of analogues that we designed based on the available structure and interaction data were synthesized and evaluated for their potency to inhibit the replication of HRV serotype 14. 2-(4,5-Dimethoxy-2-nitrophenyI)-1-(4-(pyridin-4-yl)phenyl)ethanol (3v) was found to be a potent inhibitor exhibiting micromolar activity (EC50 = 3.4 +/- 1.0 mu M) with a toxicity for HeLa cells that was significantly lower than that of our previous hit (LPCRW_0005, CC50 = 104.0 +/- 22.2 mu M: 3v, CC50 > 263 mu M). (C) 2016 Elsevier Masson SAS. All rights reserved.
    Mots-clés : 3c protease, attachment, Capsid inhibitors, common cold, compound, derivatives, design, hrv14, In silico design, original synthesis, replication, strategy, tdae, tdae methodology, VP1 protein.

  • de Medeiros, V. C.; de Andrade, R. B.; Leitao, E. F. V.; Ventura, E.; Bauerfeldt, G. F.; Barbatti, M.; do Monte, S. A. Journal of the American Chemical Society 2016, 138 (1), 272-280.
    Résumé : State-of-the-art electronic structure calculations (MR-CISD) are used to map five different dissociation channels of CH3Cl along the C-Cl coordinate: (i) CH3((X) over tilde (2)A(2)'') + Cl(P-2), (ii) CH3(3s(2)A(1)') + Cl(P-2), (iii) CH3+((1)A(1)' + Cl-(S-1), (iv) CH3(3p(2)E ') + Cl(P-2), and (v) CH3(3p(2)A(2)'') + Cl(P-2). By the first time these latter four dissociation channels, accessible upon VUV absorption, are described. The corresponding dissociation limits, obtained at the MR-CISD+Q level, are 3.70, 9.50, 10.08, 10.76, and 11.01 eV. The first channel can be accessed through n sigma* and n3s states, while the second channel can be accessed through n(e)3s, n(e)3p(sigma) and sigma 3s states. The third channel, corresponding to the CH3+ + Cl- ion-pair, is accessed through n(e)3p(e) states. The fourth is accessed through n(e)3p(e), n(e)3p(sigma), and sigma 3p(sigma), while the fifth through sigma 3p(e) and sigma(CH)sigma* states. The population of the diverse channels is controlled by two geometrical spots, where intersections between multiple states allow a cascade of nonadiabatic events. The ion-pair dissociation occurs through formation of CH3+center dot center dot center dot Cl- and H2CH+center dot center dot center dot Cl- intermediate complexes bound by 3.69 and 4.65 eV. The enhanced stability of the H2CH+center dot center dot center dot Cl- complex is due to a CH center dot center dot center dot Cl hydrogen bond. A time-resolved spectroscopic setup is proposed to detect those complexes.
    Mots-clés : chlorine atoms, correlated molecular calculations, doppler spectroscopy, excitation-energies, gaussian-basis sets, mr-ci level, nonadiabatic coupling terms, photodissociation dynamics, potential-energy surfaces, rydberg states.

  • Dekhil, M.; Mollica, G.; Bonniot, T. T.; Ziarelli, F.; Thureau, P.; Viel, S. Chemical Communications 2016, 52 (55), 8565-8568.
    Résumé : We present a solid-state NMR methodology capable of investigating the carbon skeleton of natural abundance organic powders. The methodology is based on the C-13-C-13 dipolar coupling interaction and allows carbon-carbon connectivities to be unambiguously established for a wide range of organic solids. This methodology is particularly suitable for disordered solids, such as natural or synthetic macromolecules, which cannot be studied using conventional diffraction or NMR techniques.
    Mots-clés : c-13-c-13 correlation, correlation spectroscopy, crystal-structure, disordered solids, isotopic abundance, mas nmr, nuclear-magnetic-resonance, pulse sequence, rotating solids, solid-state nmr.

  • Dol, C.; Bertrand, M. P.; Gastaldi, S.; Besson, E. Tetrahedron 2016, 72 (48), 7744-7748.
    Résumé : Upon irradiation at room temperature, symmetrical diazene precursors enabled the formation of phenoxyl radicals through beta-fragmentation reaction in the solid state. This traceless generation of phenoxyl radicals was investigated by ESR. This study showed that although the fragmentation of beta-phenoxy radicals is a slow process in solution, it could be useful in solid state thanks to the absence of faster competitive pathways. (C) 2016 Elsevier Ltd. All rights reserved.
    Mots-clés : aryloxy-radicals, batteries, beta-fragmentation reaction, chemistry, electron-spin-resonance, esr, hindered phenols, mechanism, oxidation, Phenoxyl radical, rate constants, solvent, spectra.

  • Dumur, F.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Accounts of Chemical Research 2016, 49 (9), 1980-1989.
    Résumé : Photoinitiated polymerization has been the subject of continued research efforts due to the numerous applications in which this polymerization technique is involved (coatings, inks, adhesives, optoelectronic, laser imaging, stereolithography, nanotechnology, etc.). More recently, photopolymerization has received renewed interest due to the emergence of 3D-printing technologies. However, despite current academic and industrial interest in photopolymerization methodologies, a major limitation lies in the slow rates of photopolymerization. The development of new photoinitiating systems aimed at addressing this limitation is an active area of research. Photopolymerization occurs through the exposure of a curable formulation to light, generating radical and/or cationic species to initiate polymerization. At present, photopolymerization is facing numerous challenges related to safety, economic and ecological concerns. Furthermore, practical considerations such as the curing depth and the competition for light absorption between the chromophores and other species in the formulation are key parameters drastically affecting the photopolymerization process. To address these issues, photoinitiating systems operating under low intensity visible light irradiation, in the absence of solvents are highly sought after. In this context, the use of photoredox catalysis can be highly advantageous; that is, photoredox catalysts can provide high reactivities with low catalyst loading, permitting access to high performance photoinitiating systems. However, to act as efficient photoredox catalysts, specific criteria have to be fulfilled. A strong absorption over the visible range, an ability to easily oxidize or reduce as well as sufficient photochemical stability are basic prerequisites to make these molecules desirable candidates for photoredox catalysis. Considering the similarity of requirements between organic electronics and photopolymerization, numerous materials initially designed for applications in organic electronics have been revisited in the context of photopolymerization. Organic electronics is a branch of electronics and materials science focusing on the development of semiconductors devoted to three main research fields; organic light-emitting diodes (OLEDs), organic field-effect transistors (OFETs), and organic solar cells (OSCs). The contribution of organic electronics to the field of electronics is important as it paves the way toward cheaper, lighter, and more energy efficient devices. In the present context of photopolymerization, materials that were investigated as photocatalysts were indifferently organic semiconductors used for transistors, charge-transport materials, and light-emitting materials used in electroluminescent devices or conjugated polymers and small molecule dyes for solar cells. In this Account, we summarize our latest developments in elaborating on photocatalytic systems based on these new classes of compounds. Through an in-depth understanding of the parameters governing their reactivities and our efforts to incorporate these materials into photoinitiating systems, we provide new knowledge and a valuable insight for future prospects.
    Mots-clés : ancillary ligands, cyclometalated iridium(iii) complexes, green-light, high-performance, ir(iii) complexes, light-emitting devices, Photoinitiating systems, transfer radical polymerization, visible-light, zinc-complexes.

  • Dumur, F.; Reculusa, S.; Mruczkiewicz, M.; Perrin, M.; Vignau, L.; Fasquel, S. Optics Express 2016, 24 (24), 27184-27198.
    Résumé : Three-dimensional Langmuir-Blodgett films made of silica beads are theoretically and experimentally investigated in order to improve the relatively small efficiency of blue OLEDs. Using films made of 5 layers of beads, we fabricated OLEDs emitting at 476 nm, and measured a gain of around 40% on their external quantum efficiency. An optical model has been developed to accurately handle the fact that the organic emitting layer and the photonic extraction layer are separated by a distance greater than 1000 wavelength. The latter also permits to describe rapidly this three-dimensional optical OLED cavity, without redoing all the numerical simulations when the optical properties of the organic layers are changed (material index, thicknesses). (C) 2016 Optical Society of America
    Mots-clés : devices, enhancement, extraction efficiency, indium tin oxide, light-emitting-diodes, molecule, organic solar-cells, scattering, spontaneous emission, substrate.

  • Fazzi, D.; Barbatti, M.; Thiel, W. Journal of the American Chemical Society 2016, 138 (13), 4502-4511.
    Résumé : Exciton dynamics governs energy transfer and charge generation in organic functional materials. We investigate high-energy nonadiabatic excited-state dynamics for a bithiophene dimer to describe time-dependent excitonic effects in molecular aggregates. We show that the lowest excited states are populated on the subpicosecond time scale. These states are localized and unproductive in terms of charge separation. Productive high-energy charge-transfer (CT) states are populated within 50 fs during exciton deactivation, but they are short-lived (similar to 100 fs) and quickly transfer their population to lower states. Our simulations offer molecular-level insights into ultrafast photoinduced charge separation potentially triggered by hot CT states in solid-state organic materials. Design rules are suggested to increase hot exciton lifetimes, favoring the population of CT states as gateways for direct charge generation. These rules may boost the CT quantum yield by depleting unproductive recombination channels.
    Mots-clés : conjugated materials, excited-state, internal-conversion, organic semiconductors, photovoltaics, polymer, separation, solar-cells, thiophene, transport.

  • Fouquet, T.; Ziarelli, F.; Sato, H.; Charles, L. International Journal of Mass Spectrometry 2016, 402, 42-48.
    Résumé : Poly(methoxymethylsiloxane)s (PMMS) are silicon-based polymers usually prepared according to a poorly controlled synthesis route, yielding samples of high structural dispersity. Collision induced dissociation of PMMS was hence studied in detail in order to propose MS/MS rules to be usefully employed for end-group characterization. Lithium adduction did not provide meaningful insights through charge remote dissociation while ammonium adduction allowed PMMS to readily dissociate according to two main information-rich charge driven routes. On one hand, after precursor ions have eliminated methanol together with ammonia, a series of 46 Da (CH2O + CH4) losses was observed, the number of which could be used to decipher the polymerization degree of the dissociating precursor. On the other hand, cleavage of Si-O bonds in the polymer backbone generated two series of product ions of low m/z values, each containing one or the other end-group found to be methoxy and tetramethyltetramethoxycyclotetrasiloxy terminations. Proposed mechanisms were all supported by accurate mass measurements and MS3 experiments. Based on these two highly complementary routes, the three main species of a PMMS sample were thoroughly characterized, allowing unique insights on the synthesis mechanism. (C) 2016 Elsevier B.V. All rights reserved.
    Mots-clés : adducts, dissociation, gas-phase, improvement, ions, oligomers, polymer, Polymethoxymethylsiloxane, Silicone, Siloxane, state, Structural characterization, tandem mass spectrometry.

  • Garra, P.; Dumur, F.; Morlet-Savary, F.; Dietlin, C.; Fouassier, J. P.; Lalevee, J. Macromolecules 2016, 49 (17), 6296-6309.
    Résumé : Efficient redox initiating systems for radical polymerizations under air usually show some severe drawbacks such as handling and toxicity of the oxidizing agent (peroxides, persulfates, peroxidiphosphates, disulfides, etc.), toxicity of the reducing agent (aromatic amines such as 4-N,N-trimethylaniline), and more generally a low top surface conversion due to high oxygen inhibition. The originality of the proposed paper relies on the development of new redox initiating systems for the polymerization of (meth)acrylate monomers that does not contain any hazardous compound (no peroxide) and is amine free (low toxicology issues). And these new systems that possess the advantages of redox-initiated polymerization (possibility to cure thick samples) can also be photoactivated in order to have a faster and better curing of the surface of the sample (advantages of the photopolymerization to overcome the oxygen inhibition). The light activations presented in this work have been done with light-emitting diodes (LEDs) as they have a low energy consumption and are safer to the user than UV light. Two wavelengths have been used: 405 nm (in the blue range of the spectrum) and 780 nm (in the near-infrared) showing the versatility of these new photo/redox initiating systems. In particular, the reactivity in the near-IR (not related to any heating, of the sample) is a very original result. In addition with the presentation of the performance of the new Systems in polymerization and photoactivated polymerization, a full analysis of the chemical mechanisms and species involved has been performed. Remarkably, the new proposed Cu(acac)(2)/2dppba system is also able to overcome the oxygen inhibition for free radical redox (photo)polymerization.
    Mots-clés : cationic-polymerization, complexes, copper, crystal-structure, dental resins, depth, ligands, mechanism, raman, visible-light.

  • Gaston, F.; Dupuy, N.; Marque, S. R. A.; Barbaroux, M.; Dorey, S. Radiation Physics and Chemistry 2016, 125, 115-121.
    Résumé : The multilayer films made of polyethylene/polyethylene-co-vinyl alcohol/polyethylene are gamma-irradiated for biopharmaceutical and biotechnological applications. The radiations generate changes in the polymer films. In this study, we focused on the modifications produced on the surface of materials by Fourier transformed infrared (FTIR) spectroscopy combined with chemometric treatments. Principal component analysis (PCA) allows the ordering of the surface modifications according to absorbed doses and the natural ageing. Results show the rising of the acid band and the variation of unsaturated compounds. (C) 2016 Elsevier Ltd. All rights reserved.
    Mots-clés : antioxidants, chain scission, copolymers, degradation, Fourier transform infrared spectroscopy, gamma-irradiation, lldpe, low-density polyethylene, Multilayer film, oxidation-products, Polyethylene, Principal component analysis, radiation, spectroscopy.

  • Gaston, F.; Dupuy, N.; Marque, S. R. A.; Barbaroux, M.; Dorey, S. Polymer Degradation and Stability 2016, 129, 19-25.
    Résumé : In the biopharmaceutical and biotechnological industries, disposable plastic bags are used to replace stainless steel vessels. A single-use bag is made up of a film, very often a multilayer structure, which provides good sealability of the contact layer, robustness and barrier to gas. Ethylene vinyl acetate (EVA) is one of the materials constitutive of this multilayer structure. Because these single-use plastic bags have to be sterile upon delivery, they are irradiated at doses between 25 and 45 kGy. The present work aims to investigate the effects of gamma-irradiation on the surface of the multilayer film by Fourier Transform Infrared (FTIR) spectroscopy. Optical spectroscopy techniques are of great interest for chemical analysis and are used to obtain information on the composition of materials, in our present case polymers. The chemical changes are monitored over time (up to 12 months) after gamma-irradiation (up to 270 kGy) using FTIR to study the composition and stability of the film. The chemometric method called Principal Component Analysis (PCA) is used to highlight the changes in shift or intensity in the oxidation zone and in the unsaturated group zone. (C) 2016 Elsevier Ltd. All rights reserved.
    Mots-clés : antioxidants, behavior, copolymers, degradation, Degradation mechanisms, Ethylene vinyl acetate, Fourier transform infrared spectroscopy, gamma-irradiation, low-density polyethylene, Multilayer film, Principal component analysis, spectroscopy, vinyl-acetate.

  • Geetha, K.; Rekha, T. N.; Umadevi, M.; Rajkumar, B. J. M.; Sathe, G. V.; Vanelle, P.; Terme, T.; Khoumeri, O. Australian Journal of Chemistry 2016, 69 (1), 76-84.
    Résumé : Surface-enhanced Raman scattering (or spectroscopy), commonly known as SERS, has been employed to investigate the adsorption mechanism and orientation of 1,4-dimethoxy-2-nitro-3-methylanthracene-9,10-dione (DMNMAD) molecule onto silver. Silver nanoparticles (Ag NPs) were synthesized based on a solution combustion method using citric acid as a fuel. Scanning electron microscopy and transition electron microscopy studies confirm the crystalline nature and morphology of the synthesized silver nanoparticles. Theoretical normal Raman spectra (nRs) and SERS spectra of the DMNMADmolecule, simulated based on DFT/B3PW91 level of theory were validated experimentally. Experimental and theoretical vibrational modes correlate well, confirming the reliable assignments of the vibrational bands. Enhancement of C=O stretching and C-H in-plane vibrational modes in the SERS spectrum indicates the 'stand-on' orientation of the molecule on the silver nanoparticles after adsorption. The frontier molecular orbitals confirm the charge transfers between the molecule and silver nanoparticles following the process of adsorption. As anthraquinone derivatives have been recently used as potent anti-tumour drugs, the adsorption studies reported in the current investigation can pave way to the potential application of DMNMAD in drug delivery.
    Mots-clés : acid, clusters, density-functional theory, enhanced raman-spectroscopy, ft-raman, homo-lumo, molecular-structure, orientation, torsional barriers, vibrational-spectra.

  • Gellis, A.; Primas, N.; Hutter, S.; Lanzada, G.; Remusat, V.; Verhaeghe, P.; Vanelle, P.; Azas, N. European Journal of Medicinal Chemistry 2016, 119, 34-44.
    Résumé : A DMAP catalyzed synthesis of new 4-benzyloxy- and 4-aryloxy-2-trichloromethylquinazolines was studied, in a view to react 4-chloroquinazolines with poorly nucleophilic alcohols such as benzylic alcohols, via a simple and cheap SNAr reaction approach. A fast (1 h) general operating procedure, affording good reaction yields, was achieved under microwave irradiation. Thus, a series of 35 molecules was obtained and evaluated in vitro on the K1 multi-resistant Plasmodium falciparum strain, in parallel with a cytotoxicity assessment on the human HepG2 cell line. 5 hit-molecules were identified, presenting both promising antiplasmodial activity (1.5 mu M < IC50 < 2 mu M) and low cytotoxicities (25 mu M < CC50 < 45 mu M). Apart for 2 molecules, the global series displayed a satisfying solubility in the aqueous biological media. Structure-activity relationships showed that the molecules presenting a benzyloxy moiety were less cytotoxic than the ones bearing a phenoxy moiety at position 4 of the quinazoline ring. It also appeared that the introduction of a heteroaryl moiety afforded inactive compounds. Finally, the most active and selective molecules (Selectivity Index = 22-27) were the ones presenting either an unsubstituted benzyloxy group or a phenoxy group, this last bearing a p-bromo or an o-acetyl substituent. (C) 2016 Elsevier Masson SAS. All rights reserved.
    Mots-clés : 2-trichloromethylquinazoline, 4-benzyloxyquinazoline, 4-phenoxyquinazoline, agents, agonists, Antiplasmodial activity, biological evaluation, derivatives, design, DMAP-catalysis, HepG2 cytotoxicity, methyltransferase inhibitors, Microwave-assisted chemistry, Plasmodium falciparum, SARs, series, SNAr reaction.

  • Greillier, L.; Tounsi, A.; Berenguer-Daize, C.; Dussault, N.; Delfino, C.; Benyahia, Z.; Cayol, M.; Mabrouk, K.; Garcia, S.; Martin, P. - M.; Barlesi, F.; Ouafik, L. 'H. Journal of Thoracic Oncology 2016, 11 (1), 94-107.
    Résumé : Introduction: Malignant pleural mesothelioma (MPM) grows aggressively within the thoracic cavity and has a very low cure rate, thus highlighting the need for identification of new therapeutic targets. Adrenomedullin (AM) is a multifunctional peptide that is highly expressed in several tumors and plays an important role in angiogenesis and tumor growth after binding to its receptors, calcitonin receptor-like receptor/receptor activity-modifying protein 2 (CLR/RAMP2) and calcitonin receptor-like receptor/receptor activity-modifying protein 3 (CLR/RAMP3). Methods: Real time quantitative reverse transcriptase polymerase chain reaction (RT-PCR) was used to assess the steady-state levels of AM, CLR, RAMP2 and RAMP3 messenger RNA (mRNA) transcripts in normal pleural tissue (n=5) and MPM (n=24). The expression of these candidates at protein level was revealed by immunohistochemistry. We also characterized the expression and regulation by hypoxia of AM system in MPM cell lines and MeT-5A cells. In vitro and in vivo studies were performed to determine the functional role of AM system in MPM. Results: In this study, real-time quantitative reverse transcriptase polymerase chain reaction showed twofold to 10 fold higher levels of AM messenger RNA in MPM tissue than in normal pleural tissue. The MPM cell lines H2452, H2052, and human mesothelioma cell line MSTO-211H showed a significant increase in expression of AM messenger RNA under hypoxic conditions. Our results also show that AM stimulates cell proliferation in vitro through the Raf1 protooncogene, serine/threonine kinase (CRAF)/Mitogen-activated protein kinase kinase 1 (MEIC)/Extracellular regulated MAPKinase (ERK) pathway. Furthermore, the proliferation, migration, and invasion of MPM cells were decreased after treatment with anti-AM (alpha AM) and anti-AM receptor antibodies, thus indicating that MPM cells are regulated by AM. The action of AM was specific and mediated by CLR/RAMP2 and CLR/RAMP3 receptors. In vivo, aAM and AM(22-52) antagonist therapies blocked angiogenesis and induced apoptosis in MSTO-211H xenografts, thereby resulting in tumor regression. Histologic examination of tumors treated with AM(22-52) and aAM antibody showed evidence of disruption of tumor vasculature with depletion of vascular endothelial cells and a significant decrease in lymphatic endothelial cells. Conclusions: Our findings highlight the importance of the AM pathway in growth of MPM and in neovascularization by supplying and amplifying signals that are essential for pathologic neoangiogenesis and lymphangiogenesis. (C) 2015 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.
    Mots-clés : Adrenomedullin, angiogenesis, apoptosis, endothelial growth-factor, glioblastoma cell-lines, in-vitro, Invasion, lymphangiogenesis, Mesothelioma, Neoangiogenesis- and lymphangiogenesis-associated tumors, pancreatic-cancer, receptor-like receptor, Tumor growth, tumor-cells, vivo.

  • Gunay, U. S.; Petit, B. E.; Karamessini, D.; Al Ouahabi, A.; Amalian, J. - A.; Chendo, C.; Bouquey, M.; Gigmes, D.; Charles, L.; Lutz, J. - F. Chem 2016, 1 (1), 114-126.
    Résumé : Polyurethanes (PUs) constitute a popular class of plastic materials with a wide range of applications in construction, coatings, and the automotive industry. PUs are usually synthesized by step-growth polymerization and, therefore, exhibit non-uniform molecular structures. Here, we show that uniform PUs can be prepared by a facile chemoselective multistep-growth approach. This strategy permits precise control of the chain lengths of the PUs formed and their primary structure, thus making the preparation of coded monomer sequences possible. Furthermore, it was found that these polymers are remarkably easy to analyze by tandem mass spectrometry sequencing. Thus, these precision polymers can potentially be used as molecular barcodes in various applications. As a proof of concept, their use as anti-counterfeiting tags for identification of materials is reported here.
    Mots-clés : block, chemistry, design, encoded poly(alkoxyamine amide)s, information-containing macromolecules, oligomers, phase synthesis, polymers.

  • Hajri, M.; Esteve, M. - A.; Khoumeri, O.; Abderrahim, R.; Terme, T.; Montana, M.; Vanelle, P. European Journal of Medicinal Chemistry 2016, 124, 959-966.
    Résumé : We report a novel series of quinoxaline derivatives from which agents with antiproliferative activity have been identified. Two ethyl 3-(arylethynyl)quinoxaline-2-carboxylates demonstrated substantial anti proliferative activity against both human non-small cell lung carcinoma (A549) and glioblastoma (U87-MG) cell lines. Pyrido[4,3-b]quinoxalin-1(2H)-ones demonstrated poor activity against A549 and U87-MG cell lines. Three of the derivatives in ethyl 3-(arylethynyl)quinoxaline-2-carboxylate series demonstrated substantial antiproliferative activity. The arylethynyl derivative 2a and 2d proved to be the most cytotoxic with an IC50 value of 3.3 mu M for both A549 and U87-MG cell lines. (C) 2016 Elsevier Masson SAS. All rights reserved.
    Mots-clés : Antitumor activity, assay, cell-lines, Organic chemistry, Quinoxaline, reactivity, series, Structure-activity relationship, tdae strategy.

  • Huix-Rotllant, M.; Ferre, N. Journal of Chemical Theory and Computation 2016, 12 (10), 4768-4777.
    Résumé : Normal mode analysis is nowadays routinely performed in most quantum chemistry codes as a valuable tool for studying molecular motions. In systems formed by several molecular units, such as noncovalently bound donor acceptor systems, normal modes are frequently delocalized over the whole structure, leading to a complicated interpretation of vibrations. Here, we propose a simple procedure to localize normal modes, based on the definition of fragment Hessian submatrices that lead to legitimate local fragment modes. These fragment modes can be defined for any arbitrary number of atoms and fragments and form in general a complete basis that can be used to expand the total normal modes. We use this fragment basis to explore the molecular origin of the normal modes of benzene, and several peaks in the infrared spectrum of tetraalanine. Additionally, we propose a criteria to define breathing modes in noncovalently bound systems, based on the fact that motions of the center of mass of fragments are not translational and rotational invariant with respect to the total center of mass of the system. By using the Sayvetz-Eckart conditions of fragments, we can quantify the contribution of rotation and translation of the fragments center of mass on the. normal modes of the total system.
    Mots-clés : charge-transfer, complex, energy, frequencies, infrared-spectra, orbital methods, polyatomic-molecules, scattering.

  • Huix-Rotllant, M.; Burghardt, I.; Ferre, N. Comptes Rendus Chimie 2016, 19 (1-2), 50-56.
    Résumé : When initially excited to its first singlet excited state, acetophenone, a prototypical aromatic ketone, is characterized by a singlet to triplet conversion quantum yield close to 100%. In this work, the time evolution of photo-excited acetophenone is theoretically investigated using quantum dynamics simulations based on the Multi Configuration Time Dependent Hartree (MCTDH) method. A model Hamiltonian, comprising both electronic and vibronic terms, is defined and its parameters are fitted to available data obtained by high-level quantum chemical calculations. An exploratory MCTDH dynamics shows a sequential mechanism S-1 -> T-2 -> T-1. The population in the triplet manifold is distributed evenly among the two states, explaining the origin of acetophenone rich photochemistry. Initialement excite vers son premier etat excite singulet, l'acetophenone, une cetone aromatique typique, est caracterisee par une conversion singulet vers triplet proche de 100%. Dans ce travail, l'evolution temporelle de l'acetophenone photo-excitee est etudiee de fa,on theorique par dynamique quantique basee sur la methode Multi Configuration Time Dependent Hartree (MCTDH). Un Hamiltonien modele, comprenant des termes electroniques et vibroniques, est defini et ses parametres sont determines a partir de donnees obtenues par des calculs de chimie quantique de haut niveau. La dynamique MCTDH exploratoire montre un mecanisme sequentiel S-1 -> T-2 -> T-1. La population est distribuee egalement dans les deux etats triplet, expliquant l'origine de la photochimie riche de l'acetophenone. 2015 Academie des sciences. Published by Elsevier Masson SAS.
    Mots-clés : Aromatic ketones, benzaldehyde, Chromophores, Conical intersections, direct diabatization, excitation, Femtochemistry, macrosystems, molecular dynamics, molecular-dynamics, Photochemistry, photodissociation, potential-energy surfaces, Quantum chemistry, relaxation, short-time dynamics.

  • Keloglu, N.; Verrier, B.; Trimaille, T.; Sohier, J. Colloids and Surfaces B-Biointerfaces 2016, 140, 142-149.
    Résumé : To develop bioactive scaffolds of targeted properties for tissue repair or biomedical applications, hybrid microfiber-nanoparticle (MF-NP) matrices capable of controlled nanoparticle (NP) delivery were prepared through two novel approaches. In a first strategy, the suppleness of the jet-spraying method to produce polymer microfibers (MF) was used to deposit poly(D,L-lactide) (PLA) NP on poly(lactic-co-glycolic acid) (PLGA) MF by direct co-projection. The second approach relied on the post-incubation of PLA NP aqueous dispersion with MF preliminarily prepared by jet-spraying. NP coverage density onto MF and NP release was assessed by scanning electron microscopy and fluorescence measurements using coumarin-6 loaded NP. The first process was shown to allow high coverage density of NP onto MF (300 mu g/mg MF) and strong association, with no NP release observed over time. In the second approach, direct incubation of PLA NP with PLA MF led to lower NP coverage density (40 mu g/mg MF) with very fast release of NP from MF. The pre-coating of MF with poly-L-lysine (PLL) or the one of NP with lysozyme as a model protein drug afforded a higher coverage density and stronger association, coupled with a more sustained release of NP from MF over time. These results show the possibility to control the immobilization density and release of NP through appropriate preparation process and surface modification, and are of prime interest for the development of complex scaffolds with orchestrated bioactivity. (C) 2015. Elsevier B.V. All rights reserved.
    Mots-clés : Controlled delivery, drug-delivery, loaded nanoparticles, Microfibers, microspheres, nanoparticles, pla, PLA nanoparticles, regenerative medicine, release properties, scaffold, Scaffolds, tissue engineering applications.

  • Kermagoret, A.; Gigmes, D. Tetrahedron 2016, 72 (48), 7672-7685.
    Résumé : Nitroxide mediated radical polymerization (NMP) is one of the most powerful method for advanced polymer synthesis. However, NMP suffers from some limitations, in particular to mediate the polymerization of unconjugated monomers or to conduct the polymerization of conjugated monomers under low temperatures. The combination of NMP with other reversible-deactivation radical polymerization techniques, such as reversible addition fragmentation chain transfer (RAFT), atom transfer radical polymerization (ATRP) or organometallic mediated radical polymerization (OMRP), offered new possibilities in macromolecular engineering. In this contribution we report different strategies of 'combined NMP', i.e., the exchange of the polymer chain-end controlling agents for sequenced polymerization or the introduction of different polymerization-initiating sites onto alkoxyamines or polymers. (C) 2016 Elsevier Ltd. All rights reserved.
    Mots-clés : Alkoxyamine, atom-transfer, Combined polymerization, hydrogen-transfer reaction, labile end-groups, methyl-methacrylate, mixed homopolymer brushes, n-butyl acrylate, Nitroxide mediated polymerization, poly(methyl methacrylate)/polystyrene brushes, poly(tert-butyl acrylate)/polystyrene brushes, Polymer synthesis, Reversible-deactivation radical polymerization, ring-opening polymerization, silica nanoparticles.

  • Khoumeri, O.; Vanelle, F. - X.; Crozet, M. D.; Terme, T.; Vanelle, P. Synlett 2016, 27 (10), 1547-1550.
    Résumé : We report herein the synthesis of 5-(substituted)quinolino[3,4-b]quinoxalin-6(5H)-one derivatives from ethyl 3-(2-bromophenyl)quinoxaline-2-carboxylate under one-pot Buchwald-Hartwig coupling-lactamization reaction.
    Mots-clés : agents, aromatic anilines, biological-activity, Buchwald-Hartwig reaction, catalyzed cyclization, derivatives, discovery, inhibitors, lactamization reaction, n-heterocycles, pot synthesis, Quinoxaline, quinoxaline antibiotics, series.

  • Kubicki, D. J.; Casano, G.; Schwarzwaelder, M.; Abel, S.; Sauvee, C.; Ganesan, K.; Yulikov, M.; Rossini, A. J.; Jeschke, G.; Coperet, C.; Lesage, A.; Tordo, P.; Ouari, O.; Emsley, L. Chemical Science 2016, 7 (1), 550-558.
    Résumé : A series of 37 dinitroxide biradicals have been prepared and their performance studied as polarizing agents in cross-effect DNP NMR experiments at 9.4 T and 100 K in 1,1,2,2-tetrachloroethane (TCE). We observe that in this regime the DNP performance is strongly correlated with the substituents on the polarizing agents, and electron and nuclear spin relaxation times, with longer relaxation times leading to better enhancements. We also observe that deuteration of the radicals generally leads to better DNP enhancement but with longer build-up time. One of the new radicals introduced here provides the best performance obtained so far under these conditions.
    Mots-clés : c-13, dnp, enhanced nmr, nanoparticles, polarizing agents, resonance, signal enhancement, solid-state nmr, spectroscopy, temperatures.

  • Laure, C.; Karamessini, D.; Milenkovic, O.; Charles, L.; Lutz, J. - F. Angewandte Chemie-International Edition 2016, 55 (36), 10722-10725.
    Résumé : A 2D approach was studied for the design of polymer-based molecular barcodes. Uniform oligo(alkoxyamine amide)s, containing a monomer-coded binary message, were synthesized by orthogonal solid-phase chemistry. Sets of oligomers with different chain-lengths were prepared. The physical mixture of these uniform oligomers leads to an intentional dispersity (1st dimension fingerprint), which is measured by electrospray mass spectrometry. Furthermore, the monomer sequence of each component of the mass distribution can be analyzed by tandem mass spectrometry (2nd dimension sequencing). By summing the sequence information of all components, a binary message can be read. A 4-bytes extended ASCII-coded message was written on a set of six uniform oligomers. Alternatively, a 3-bytes sequence was written on a set of five oligomers. In both cases, the coded binary information was recovered.
    Mots-clés : barcodes, containing macromolecules, data storage, electrospray-ionization, encoded poly(alkoxyamine amide)s, ions, ms/ms, oligomers, peptides, sequence-controlled polymers, solid-phase synthesis, tandem mass spectrometry.

  • Le, D.; Phan, T. N. T.; Autissier, L.; Charles, L.; Gigmes, D. Polymer Chemistry 2016, 7 (8), 1659-1667.
    Résumé : A series of carboxylic acid-based alkoxyamines associated with SnBr4, a Lewis acid, have been used as protonic acids of a binary initiating system to control the cationic polymerization of vinyl ether. The living character of the homopolymerization of isobutyl vinyl ether was investigated under various conditions (solvent, amount of catalyst, initiator structure etc.). Among the different studied dual initiators, TEMPO based-alkoxyamine showed high efficiency to lead the polymerization of isobutyl vinyl ether (IBVE) in a controlled manner. The prepared polymers exhibited high TEMPO functionality (> 0.85) and low dispersity (1.2) which is essential for the synthesis of well-defined block copolymers thereafter. TEMPO-functionalized PIBVE was used as a macro-initiator controller in the nitroxide-mediated polymerization (NMP) of styrene at 130 degrees C leading successfully to well-defined block copolymers of poly(isobutyl vinyl ether)-b-polystyrene (PIBVE-b-PS) with a narrow dispersity (1.2).

  • Lepeltier, M.; Appaix, F.; Liao, Y. Y.; Dumur, F.; Marrot, J.; Le Bahers, T.; Andraud, C.; Monnereau, C. Inorganic Chemistry 2016, 55 (19), 9586-9595.
    Résumé : A tris-cyclometalated iridium complex that beats two ligands functionalized by peripheral carbazole groups combines an intense solid state emission and a significant two photon absorption cross section in the near-infrared. After incorporation into a physiological micellar suspension, it can be used for the intravital two-photon fluorescence microscopy of cerebral vasculature.
    Mots-clés : density-based indexes, excited-states, fluorescence lifetime, iii complexes, live cells, nonlinear absorption, photophysics, probe, ruthenium(ii) complexes, vasculature.

  • Lepeltier, M.; Graff, B.; Lalevee, J.; Wantz, G.; Ibrahim-Ouali, M.; Gigmes, D.; Dumur, F. Organic Electronics 2016, 37, 24-34.
    Résumé : Two cationic iridium (III) complexes [Ir(dfppy)(tpy)(bpy)](PF6) and [Ir(dfppy)(tpy)(phen)](PF6) bearing three different ligands were tested as triplet emitters for Light-Emitting Electrochemical Cells (LECs). These two phosphorescent materials only constitute the third and fourth examples of triple heteroleptic cationic iridium complexes to be tested in electroluminescent devices. LECs fabricated with this almost unknown class of iridium complex furnished green-emitting devices. Parallel to investigations devoted to electroluminescent properties, photophysical and electrochemical properties of the two new complexes were examined. Density functional theory calculations were also performed to provide insight into the electronic structure of the two emitters. (C) 2016 Elsevier B.V. All rights reserved.
    Mots-clés : ancillary ligands, blue-green, cyclometalated iridium(iii), efficient blue, Electroluminescence, electroluminescent devices, ionic liquids, Ionic liquid, Iridium complex, Lifetime, Light-emitting electrochemical cells, phosphorescent, photopolymerization, Red, transition-metal-complexes.

  • Liu, X.; Wang, Y.; Chen, C.; Tintaru, A.; Cao, Y.; Liu, J.; Ziarelli, F.; Tang, J.; Guo, H.; Rosas, R.; Giorgio, S.; Charles, L.; Rocchi, P.; Peng, L. Advanced Functional Materials 2016, 26 (47), 8594-8603.
    Résumé : Functional materials capable of responding to stimuli intrinsic to diseases are extremely important for specific drug delivery at the disease site. However, developing on-demand stimulus-responsive vectors for targeted delivery is highly challenging. Here, a stimulus-responsive fluorinated bola-amphiphilic dendrimer is reported for on-demand delivery of small interfering RNA (siRNA) in response to the characteristic high level of reactive oxygen species (ROS) in cancer cells. This dendrimer bears a ROS-sensitive thioacetal in the hydrophobic core and positively charged poly(amidoamine) dendrons at the terminals, capable of interacting and compacting the negatively charged siRNA into nanoparticles to protect the siRNA and promote cellular uptake. The ROS-sensitive feature of this dendrimer boosts specific and efficient disassembly of the siRNA/vector complexes in ROS-rich cancer cells for effective siRNA delivery and gene silencing. Moreover, the fluorine tags in the vector enable F-19-NMR analysis of the ROS-responsive delivery process. In addition, this ingenious and distinct bola-amphiphilic dendrimer is also able to combine the advantageous delivery features of both lipid and dendrimer vectors. Therefore, it represents an innovative on-demand stimulus-responsive delivery platform.
    Mots-clés : androgen ablation, cells, drug-delivery, efficient, in-vivo, nanomedicine, nanoparticles, prostate-cancer, rnai, therapeutics.

  • Manathunga, M.; Yang, X.; Luk, H. L.; Gozem, S.; Manuel Frutos, L.; Valentini, A.; Ferre, N.; Olivucci, M. Journal of Chemical Theory and Computation 2016, 12 (2), 839-850.
    Résumé : While the light-induced population dynamics of different photoresponsive proteins has been investigated spectroscopically, systematic computational. studies have not yet been possible due to the phenomenally high cost of suitable high level quantum chemical methods and the need of propagating hundreds, if not thousands, of nonadiabatic trajectories. Here we explore the possibility of studying the photodynamics of rhodopsins by constructing and investigating quantum mechanics/molecular mechanics (QM/MM) models featuring reduced retinal chromophores. In order to do so we use the sensory rhodopsin found in the cyanobacterium Anabaena PCC7120 (ASR) as a benchmark system. We find that the basic mechanistic features associated with the excited state dynamics of ASR QM/MM models are reproduced using models incorporating a minimal (i.e., three double-bond) chromophore. Furthermore, we show that ensembles of nonadiabatic ASR trajectories computed using the same abridged models replicate, at both the CASPT2 and CASSCF levels of theory, the trends in spectroscopy and lifetimes estimated using unabridged models and observed experimentally at room temperature. We conclude that a further expansion of these studies may lead to low-cost QM/MM rhodopsin models that may be used as effective tools in high-throughput in silico mutant screening.
    Mots-clés : 1st step, anabaena sensory rhodopsin, conical intersection, density-functional theory, model, motion coupled-cluster, perturbation-theory, photoisomerization, potential-energy surface, quantum yield.

  • Melaccio, F.; Marin, M. del C.; Valentini, A.; Montisci, F.; Rinaldi, S.; Cherubini, M.; Yang, X.; Kato, Y.; Stenrup, M.; Orozco-Gonzalez, Y.; Ferre, N.; Luk, H. L.; Kandori, H.; Olivucci, M. Journal of Chemical Theory and Computation 2016, 12 (12), 6020-6034.
    Résumé : We report on a prototype protocol for the automatic and fast construction of congruous sets of QM/MM models of rhodopsin-like photoreceptors and of their mutants. In the present implementation the information required for the construction of each model is essentially a crystallographic structure or a comparative model complemented with information on the protonation state of ionizable side chains and distributions of external counterions. Starting with such information, a model formed by a fixed environment system, a flexible cavity system, and a chromophore system is automatically generated. The results of the predicted vertical excitation energy for 27 different rhodopsins including vertebrate, invertebrate, and microbial pigments indicate that such basic models could be employed for predicting trends in spectral changes and/or correlate the spectral changes with structural variations in large sets of proteins.
    Mots-clés : anabaena sensory rhodopsin, crystal-structure, excited-state relaxation, perturbation-theory, potential-energy surface, protonation state, qm/mm calculations, retinal chromophore model, squid rhodopsin, visual pigments.

  • Mokbel, H.; Dumur, F.; Raveau, B.; Morlet-Savary, F.; Simonnet-Jegat, C.; Gigmes, D.; Toufaily, J.; Hamieh, T.; Fouassier, J. P.; Lalevee, J. Tetrahedron 2016, 72 (48), 7686-7690.
    Résumé : Four perovskites (LaTiO3, LaCrO3, La0.6Sr0.4MnO3 and MAPbl(3)) are proposed here as new photoinitiators (e.g., free radical generators) in combination with iodonium salt and optionally another additive (N-vinylcarbazole-NVK) to initiate both radical and cationic photopolymerization reactions. The proposed systems are efficient phenyl radical generators under polychromatic light sources such as a halogen lamp or a Xe-Hg lamp. The interest of this approach is the ability to work with very stable inorganic structures as photoinitiators. To the best of our knowledge, this is the first time that perovskites are incorporated in photoinitiating systems. Photochemical mechanisms will be proposed as sustained by electron spin resonance spin trapping (ESR-ST) experiments. (C) 2016 Elsevier Ltd. All rights reserved.
    Mots-clés : Cationic polymerization, crystal-chemistry, efficient, Free radical initiators, giant magnetoresistance, initiating systems, n-vinylcarbazole, oxides, Perovskites, Photoinitiator, photopolymerization, Polychromatic light, Polymerization, sensitized solar-cell, state, visible-light.

  • Mokbel, H.; Poriel, C.; Rault-Berthelot, J.; Dumur, F.; Gigmes, D.; Toufaily, J.; Hamieh, T.; Cordella, D.; Detrembleur, C.; Fouassier, J. P.; Lalevee, J. Journal of Applied Polymer Science 2016, 133 (12), 43213.
    Résumé : d A novel photoinitiator based on a spiroxanthene scaffold in the presence of an iodonium salt is proposed for the cationic ring-opening polymerization of a diepoxide, as well as for the free-radical polymerization of an acrylate upon violet LED exposure (385 and 405 nm). Good-to-excellent rates of polymerization and final conversions are obtained. These systems are characterized by a higher reactivity compared with that of anthracene/iodonium salt used as reference for cationic near UV polymerization. The addition of a poly(ionic liquid) improves the cationic polymerization profiles. The photochemical mechanisms are studied by steady-state photolysis, fluorescence, and electron spin resonance spin-trapping techniques. Molecular orbital calculations give an insight into the light absorption properties. (C) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43213.

  • Oswald, L.; Al Ouahabi, A.; Charles, L.; Lutz, J. - F. Chemistry-a European Journal 2016, 22 (10), 3462-3469.
    Résumé : Soluble polystyrene supports with optimal molecular structures for iterative phosphoramidite chemistry were prepared by atom-transfer radical polymerization (ATRP) and subsequent chain-end modification steps. The controlled radical polymerization of styrene was first performed in the presence of an 9-fluorenylmethoxycarbonyl (Fmoc)-protected amino-functional ATRP initiator. Soluble supports of different molecular weight were prepared. Size-exclusion chromatography and NMR analysis indicated formation of well-defined polymers with controlled chain lengths and narrow dispersity. After synthesis, the bromo end group of the ATRP polymer was removed by dehalogenation in the presence of tributyltin hydride, and the Fmoc protecting group of the moiety was subsequently cleaved with piperidine. The resulting -primary amine was afterwards treated with a linker containing a carboxyl group, a cleavable ester site, and a dimethoxytrityl-protected hydroxyl group to afford ideal soluble supports for phosphoramidite chemistry. NMR analysis indicated that these chain-end modifications were quantitative. The supports were tested for the synthesis of a non-natural sequence-defined oligophosphates. High-resolution ESI-MS analysis of the cleaved oligomers indicated formation of uniform species, and thus confirmed the efficiency of the ATRP-made soluble polymer supports. In addition, the synthesis of a thymidine-loaded soluble support was achieved.
    Mots-clés : deoxyribooligonucleotide synthesis, design, encoded polymers, information-containing macromolecules, information-containing oligomers, iterative synthesis, liquid-phase synthesis, peptide-synthesis, Polymerization, polymers, soluble supports, transfer radical polymerization.

  • Rayala, R.; Giuglio-Tonolo, A.; Broggi, J.; Terme, T.; Vanelle, P.; Theard, P.; Medebielle, M.; Wnuk, S. F. Tetrahedron 2016, 72 (16), 1969-1977.
    Résumé : Studies directed toward the oxidative and reductive desulfurization of readily available 2'-S-ary1-2'thiouridine derivatives were investigated with the prospect to functionalize the C2'-position of nucleosides. The oxidative desulfurization-difluorination strategy was successful on 2-(arylthio)allcanoate surrogates, while extension of the combination of oxidants and fluoride sources was not an efficient fluorination protocol when applied to 2'-S-aryl-2'-thiouridine derivatives, resulting mainly in C5 halogenation of the pyrimidine ring and C2'-monofluorination without desulfurization. Cyclic voltammetry of 2'-arylsulfony1-2'-deoxyuridines and their 2'-fluorinated analogues showed that cleavage of the arylsulfone moiety could occur, although at relatively high cathodic potentials. While reductivedesulfonylation of 2'-arylsulfciny1-2'-deoxyuridines with organic electron donors (0EDs) gave predominantly base-induced furan type products, chemical (OED) and electrochemical reductivedesulfonylation of the cc-fluorosulfone derivatives yielded the 2'-deoxy-2'-fluorouridine and 2',3'-didehydro-2',3'-dideoxy-2'-fluorouridine derivatives. These results provided good evidence of the generation of a C2'-anion through carbon-sulfur bond cleavage, opening new horizons for the reductivefunctionalization approaches in nucleosides. (C) 2016 Elsevier Ltd. All rights reserved.
    Mots-clés : acid related-compounds, alkyl aryl thioethers, alpha-fluoro esters, Cyclic voltammetry, desulfurization-difluorination, Desulfurization-fluorination, electrochemical synthesis, Fluorination, medicinal chemistry, Nucleosides, organic electron donors, radical-mediated cleavage, Reductive desulfonylation, super-electron-donors.

  • Rodrigues, G. P.; Ventura, E.; do Monte, S. A.; Barbatti, M. Journal of Computational Chemistry 2016, 37 (7), 675-683.
    Résumé : The UV-induced photochemistry of HCFC-132b (CF2ClCH2Cl) was investigated by computing excited-state properties with time-dependent density functional theory (TDDFT), multiconfigurational second-order perturbation theory (CASPT2), and coupled cluster with singles, doubles, and perturbative triples (CCSD(T)). Excited states calculated with TDDFT show good agreement with CASPT2 and CCSD(T) results, correctly predicting the main excited-states properties. Simulations of ultrafast nonadiabatic dynamics in the gas phase were performed, taking into account 25 electronic states at TDDFT level starting in two different spectral windows (8.5 +/- 0.25 and 10.0 +/- 0.25 eV). Experimental data measured at 123.6 nm (10 eV) is in very good agreement with our simulations. The excited-state lifetimes are 106 and 191 fs for the 8.5 and 10.0 eV spectral windows, respectively. Internal conversion to the ground state occurred through several different reaction pathways with different products, where 2Cl, C-Cl bond breakage, and HCl are the main photochemical pathways in the low-excitation region, representing 95% of all processes. On the other hand, HCl, HF, and C-Cl bond breakage are the main reaction pathways in the higher excitation region, with 77% of the total yield. (c) 2015 Wiley Periodicals, Inc.
    Mots-clés : 1,2-dichloro-1,1-difluoroethane, 147 nm, atmospheric photochemistry, chlorine atom reactions, correlated molecular calculations, density functionals, excited states, gaussian-basis sets, hcfc, nonadiabatic dynamics, nonadiabatic dynamics, photo-decomposition, Photochemistry, photodissociation, surface hopping, ultraviolet-absorption, vacuum-ultraviolet.

  • Rollet, M.; Pelletier, B.; Berek, D.; Maria, S.; Phan, T. N. T.; Gigmes, D. Journal of Chromatography A 2016, 1462, 63-72.
    Résumé : Liquid Chromatography under Limiting Conditions of Desorption (LC LCD) is a powerful separation tool for multicomponent polymer systems. This technique is based on a barrier effect of an appropriate solvent, which is injected in front of the sample, and which decelerates the elution of selected macromolecules. In this study, the barrier effects have been evaluated for triblock copolymers polystyrene-b-poly(ethylene oxide)-b-polystyrene (PS-b-PEO-b-PS) according to the content of polystyrene (wt% PS) and PEO-block molar mass. PS-b-PEO-b-PS samples were prepared by Atom Transfer Radical Polymerization (ATRP). The presence of respective parent homopolymers was investigated by applying optimized LC LCD conditions. It was found that the barrier composition largely affects the efficiency of separation and it ought to be adjusted for particular composition range of block copolymers. (C) 2016 Elsevier B.V. All rights reserved.
    Mots-clés : adsorption, Barriers efficiency, complex polymers, diblock copolymers, electrolytes, Liquid chromatography under limiting conditions of desorption, Nitroxide-mediated polymerization, Polystyrene-b-poly(ethylene oxide)-b-polystyrene, size-exclusion chromatography, Triblock copolymers.

  • Salnikov, E. S.; Aisenbrey, C.; Aussenac, F.; Ouari, O.; Sarrouj, H.; Reiter, C.; Tordo, P.; Engelke, F.; Bechinger, B. Scientific Reports 2016, 6, 20895.
    Résumé : Dynamic Nuclear Polarization (DNP) has been introduced to overcome the sensitivity limitations of nuclear magnetic resonance (NMR) spectroscopy also of supported lipid bilayers. When investigated by solid-state NMR techniques the approach typically involves doping the samples with biradicals and their investigation at cryo-temperatures. Here we investigated the effects of temperature and membrane hydration on the topology of amphipathic and hydrophobic membrane polypeptides. Although the antimicrobial PGLa peptide in dimyristoyl phospholipids is particularly sensitive to topological alterations, the DNP conditions represent well its membrane alignment also found in bacterial lipids at ambient temperature. With a novel membrane-anchored biradical and purpose-built hardware a 17-fold enhancement in NMR signal intensity is obtained by DNP which is one of the best obtained for a truly static matrix-free system. Furthermore, a membrane anchor sequence encompassing
    Mots-clés : angle, enhanced nmr, high-frequency, lipid-bilayers, magnetic-resonance, polarizing agents, polypeptides, protein, solids, Temperature.

  • Sauvee, C.; Casano, G.; Abel, S.; Rockenbauer, A.; Akhmetzyanov, D.; Karoui, H.; Siri, D.; Aussenac, F.; Maas, W.; Weber, R. T.; Prisner, T.; Rosay, M.; Tordo, P.; Ouari, O. Chemistry-a European Journal 2016, 22 (16), 5598-5606.
    Résumé : A series of 18 nitroxide biradicals derived from bTurea has been prepared, and their enhancement factors (H-1) in cross-effect dynamic nuclear polarization (CEDNP) NMR experiments at 9.4 and 14.1T and 100K in a DNP-optimized glycerol/water matrix (DNP juice) have been studied. We observe that (H-1) is strongly correlated with the substituents on the polarizing agents, and its trend is discussed in terms of different molecular parameters: solubility, average e-e distance, relative orientation of the nitroxide moieties, and electron spin relaxation times. We show that too short an e-e distance or too long a T-1e can dramatically limit (H-1). Our study also shows that the molecular structure of AMUPol is not optimal and its (H-1) could be further improved through stronger interaction with the glassy matrix and a better orientation of the TEMPO moieties. A new AMUPol derivative introduced here provides a better (H-1) than AMUPol itself (by a factor of ca. 1.2).
    Mots-clés : broadened esr line, dinitroxides, glassy solvents, high-frequency, magnetic-resonance, metal-organic frameworks, molecular dynamics, nitroxyl radicals, organic synthesis, polarizing agents, sensitivity-enhanced nmr, sn-beta zeolite, solid-state nmr, solvent effects, theoretical aspects.

  • Spitz, C.; Mathias, F.; Giuglio-Tonolo, A. G.; Terme, T.; Vanelle, P. Molecules 2016, 21 (11), 1472.
    Résumé : We report here a practical and metal-free synthesis of novel enantiopure amides containing the drug-like 5-nitroimidazole scaffold. The first step was a metal-free diastereoselective addition of 4-(4-(chloromethyl) phenyl)-1,2-dimethyl-5-nitro-1H-imidazole to enantiomerically pure N-tert-butanesulfinimine. Then, the N-tert-butanesulfinyl-protected amine was easily deprotected under acidic conditions. Finally, the primary amine was coupled with different acid chlorides or acids to give the corresponding amides. The mild reaction conditions and high tolerance for various substitutions make this approach attractive for constructing pharmacologically interesting 5-nitroimidazoles.
    Mots-clés : 5-nitroimidazoles, amides, derivatives, in-vitro, metal-free, metronidazole.

  • Spitz, C.; Terme, T.; Vanelle, P. Synlett 2016, 27 (2), 301-303.
    Résumé : A mild and metal-free regioselective 1,2-addition of carbon nucleophiles to alpha,beta-unsaturated imines has been developed. Good yields and total regioselectivities were achieved by addition of p-nitrobenzyl chloride or 2,3-bis(bromomethyl)quinoxaline to alpha,beta-unsaturated tosylimines.
    Mots-clés : addition, agents, aldehydes, alpha,beta-unsaturated tosylimines, derivatives, metal-free, p-nitrobenzyl chloride, regioselectivity, series, strategy, tdae.

  • Stojanovic, L.; Alyoubi, A. O.; Aziz, S. G.; Hilal, R. H.; Barbatti, M. Journal of Chemical Physics 2016, 145 (18), 184306.
    Résumé : In the present study, we examined the UV excitations of a newly introduced molecular set, Halons-9, composed of nine gaseous halon molecules. The performance of the density functional-based multi-reference configuration interaction method (DFT/MRCI) and time-dependent density functional theory with CAM-B3LYP functional (TD-CAM-B3LYP) in the computation of singlet and triplet excited states of this set was evaluated against coupled-cluster with singles and doubles (CCSD). Excited states up to the corresponding ionization limits, including both localized and delocalized excitations, have been benchmarked. TD-CAM-B3LYP significantly underestimates excitation energies of the higher mixed valence-Rydberg and Rydberg states, with computed mean absolute deviations from the equation of motion (EOM)-CCSD results 1.06 and 0.76 eV, respectively. DFT/MRCI gives a significantly better description of higher excited states, albeit still poor, compared to the TD-CAM-B3LYP. The mean absolute deviations of mixed valence-Rydberg and Rydberg states from the reference EOM-CCSD values are 0.66 and 0.47 eV, respectively. The performance of DFT/MRCI for description of strongly correlated states with valence-Rydberg mixing is still not satisfactory enough. On the other hand, oscillator strengths of most of singlet states obtained with both methods are close to the EOM-CCSD values. The largest deviations, occurring in the case of several high-lying multiconfigurational states, are of an order of magnitude. Published by AIP Publishing.
    Mots-clés : absorption cross-sections, asymptotic correction, basis-sets, configuration-interaction, coupled-cluster singles, density-functional theory, electronic excitation, excited-state properties, mp2 energy, photoabsorption spectrum.

  • Stojanovic, L.; Bai, S.; Nagesh, J.; Izmaylov, A. F.; Crespo-Otero, R.; Lischka, H.; Barbatti, M. Molecules 2016, 21 (11), 1603.
    Résumé : After UV excitation, gas phase thymine returns to a ground state in 5 to 7 ps, showing multiple time constants. There is no consensus on the assignment of these processes, with a dispute between models claiming that thymine is trapped either in the first (S-1) or in the second (S-2) excited states. In the present study, a nonadiabatic dynamics simulation of thymine is performed on the basis of ADC(2) surfaces, to understand the role of dynamic electron correlation on the deactivation pathways. The results show that trapping in S-2 is strongly reduced in comparison to previous simulations considering only non-dynamic electron correlation on CASSCF surfaces. The reason for the difference is traced back to the energetic cost for formation of a CO pi bond in S-2.
    Mots-clés : ab-initio, base-pairs, computational theoretical chemistry, density-functional theory, gas-phase thymine, molecular-dynamics, nonadiabatic dynamics, nucleobases, Photochemistry, photoinduced processes, polarization propagator, pyrimidine nucleobases, resolved photoelectron-spectroscopy, rna bases, surface hopping, thymine, ultrafast processes.

  • Telitel, S.; Dumur, F.; Campolo, D.; Poly, J.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Journal of Polymer Science Part a-Polymer Chemistry 2016, 54 (5), 702-713.
    Résumé : This article reports on the presumably first use of iron complexes (FeC) as potential photocatalysts for controlled radical photopolymerization reactions (CRP2). Three compounds were designed and investigated. Good linear evolutions of the molecular weight (Mn) with the conversion were observed. A comparison was provided with a reference iridium (III) complex [Ir(ppy)3 where ppy stands for 2-phenylpyridine]. The on/off photopolymerization experiments highlight the presence of dormant species and a re-initiation on demand upon irradiation. This unique re-initiation property was used for the modification of surfaces (hydrophilic/hydrophobic properties) and surface patterning as well as the synthesis of a block co-polymer (PMMA-b-PBA). A comparative analysis of the behavior of these iron complexes in thermally and photochemically activated polymerization was provided. The chemical mechanisms were studied by steady state photolysis, laser flash photolysis, cyclic voltammetry, luminescence quenching, and electron spin resonance experiments. A catalytic cycle was proposed with two steps: (i) the oxidation of the FeC excited state by an alkyl halide and (ii) the reduction by the oxidized form (FeC degrees+) by an amine or the macroradicals leading to the regeneration of the catalyst. (c) 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 702-713

  • Toure, M.; Charles, L.; Chendo, C.; Viel, S.; Chuzel, O.; Parrain, J. - L. Chemistry-a European Journal 2016, 22 (26), 8937-8942.
    Résumé : A straightforward synthesis of air- and water-stable bis-cationic macrocyclic imidazolylboronium anion receptors is described herein. By taking advantage of the bulky and rigid 9-borabicyclo[3.3.1]-nonane (9-BBN) attaching point and a well-designed bis-imidazolylaryl, highly stable dimeric imidazolylboronium macrocycles were synthesized. Additionally, NMR spectroscopy (H-1, DOSY, and HOESY), mass spectrometry (MS), and X-ray diffraction studies revealed that these macrocyclic scaffolds can bind several monoanions with high association constants in DMSO, and are particularly sensitive for the MS detection of anions (with concentrations in the nm range). This anion/receptor interaction involves eight C-H binding sites, which include C-sp2-H and unusual C-sp3-H hydrogen-bonding donors.
    Mots-clés : anion receptors, binding, boronium cations, chemistry highlights, complexes, dot-center-dot, driven, fluorescent, hydrogen bonds, macrocycles, NMR spectroscopy, preorganization, reactivity, recognition, special-issue.

  • Trimaille, T.; Pertici, V.; Gigmes, D. Comptes Rendus Chimie 2016, 19 (1-2), 157-166.
    Résumé : In spinal cord repair, the challenge consists in combining various therapies that account for multiple deleterious effects in order to induce an efficient recovery. In that context, biomaterial implantation seems to be highly relevant. Indeed, biomaterials not only serve as a growth support to promote sectioned axonal fibers, but are also used for cell transplantation and drug delivery. In this review, we discuss and put into perspective the recent results obtained in the field of spinal cord repair by synthetic hydrogel implantation. The versatility of those biomaterials is presented through the latest chemical strategies developed to enhance their therapeutic effects. (C) 2015 Academie des sciences. Published by Elsevier Masson SAS. This is an open access article under the CC BY-NC-ND license.
    Mots-clés : axonal regeneration, Bioadhesion, biomaterials, block-copolymers, cell-adhesion, central-nervous-system, Degradability, Drug delivery, drug-delivery, functional recovery, injury repair, polymers, reverse thermal gel, Scaffolds, Spinal cord injury, Synthetic hydrogel.

  • Verdoni, M.; Roudaut, H.; De Pomyers, H.; Gigmes, D.; Bertin, D.; Luis, J.; Bengeloune, A. H.; Mabrouk, K. Bioorganic & Medicinal Chemistry 2016, 24 (22), 5685-5692.
    Résumé : To discover new molecules with an inhibitory activity of melanogenesis a hundred of scorpions, snakes, spiders and amphibians venoms were screened for their capacity to inhibit mushroom tyrosinase using 3,4-L-dihydroxyphenylalanine (L-DOPA) as substrate. The Argiope lobata spider venom proved to be the most active. HPLC fraction containing Argiotoxine-636 (ArgTX-636), a polyamine known for its numerous biological activities, was found to also show a good regulation activity of melanogenesis by inhibiting DOPA and 5,6-dihydroxyindole-2-carboxylic acid (DHICA) oxidases activities, wore by tyrosinase (TYR) and tyrosinase-related protein 1 (TRP-1), respectively. Our results demonstrate that ArgTX-636 reduced the mushroom tyrosinase activity in a dose dependent way with a maximal half inhibitory concentration (IC50) value of 8.34 mu M, when L-DOPA is used as substrate. The Lineweaver-Burk study showed that ArgTX-636 is a mixed type inhibitor of the diphenolase activity. Moreover, ArgTX-636 inhibits DHICA oxydase activity of mushroom tyrosinase activity with IC50 at 41.3 mu M. ArgTX-636 has no cytotoxicity in B16F10 melanoma cells at concentrations up to 42.1 mu M. The effect of ArgTX-636 on melanogenesis showed that melanin production in B16F10 melanoma cell decreased by approximatively 70% compared to untreated cells. ArgTX-636 displayed no significant effect on the TYR expression while the protein level of TRP-1 decreased in B16F10 cells. Thus, ArgTX-636 could have particular interest for cosmetic and/or pharmaceutical use in order to reduce important dermatoses in black and mixed skins. (C) 2016 Elsevier Ltd. All rights reserved.
    Mots-clés : 5,6-dihydroxyindole-2-carboxylic acid, Argiotoxine, ArgTX-636, DHICA oxydase activity, DOPA oxydase activity, Hyperpigmentation, melanocytes, Melanogenesis, oxidase activity, receptors, Spider venoms, Tyrosinase, Tyrosinase related protein 1 (TRP-1).

  • Viode, A.; Dagany, X.; Kerleroux, M.; Dugourd, P.; Doussineau, T.; Charles, L.; Antoine, R. Rapid Communications in Mass Spectrometry 2016, 30 (1), 132-136.
    Résumé : RationaleCoupling size-exclusion chromatography (SEC) with mass spectrometry (MS) allowed generation of a SEC calibration curve based on the analyte itself, which is more reliable than calibration based on non-related standards and faster than the use of the multiple detection mode. However, such SEC/MS couplings were limited to rather small synthetic polymers. MethodsBased on the concept of image current detection, charge-detection mass spectrometry (CDMS) coupled to electrospray ionization (ESI) is a useful method for weighing macro-ions from compounds with masses higher than one megadalton (MDa). Using columns designed to allow analysis of synthetic polymers of over 15 million Dalton in mass, performance of the SEC/ESI-CDMS coupling was evaluated for polyacrylamide (PAM, 5-6 MDa) and a poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS, 2 MDa). ResultsThe SEC/ESI-CDMS profiles were first compared with SEC-UV profiles: the systematic shift in retention time was assigned to the slightly different geometries of the two instrumental systems. The SEC/ESI-CDMS data were then compared with results obtained after the direct infusion of each sample into the ESI source. Both the shape of the molecular weight distribution and the mass values were similar with or without separation prior to ESI, and these values were consistent with data provided by the sample supplier. ConclusionsSEC/MS incorporating an online ESI-CDMS coupling was shown to be a rapid and efficient technique for the analysis of water-soluble synthetic polymers with ultra-high molecular mass in the megadalton range. The coupling also afforded an attractive solution for SEC calibration without the use of external standards. Copyright (c) 2015 John Wiley & Sons, Ltd.

  • Zhang, J.; Campolo, D.; Dumur, F.; Xiao, P.; Fouassier, J. P.; Gigmes, D.; Lalevee, J. Journal of Polymer Science Part a-Polymer Chemistry 2016, 54 (14), 2247-2253.
    Résumé : The development of iron complexes for the photoredox catalysis is a huge challenge. Indeed, Iron complexes can be ideal candidates due to their potential visible light absorption and redox properties but also because they are less toxic, inexpensive and environmentally friendly compared to other catalysts. In the present paper, a series of novel iron complexes have been synthesized and utilized to initiate the free radical promoted cationic polymerization of epoxides or the free radical polymerization of acrylates through photoredox catalysis processes upon exposure to near UV (385 nm) or visible violet (405 nm) light emitting diodes (LEDs). When combined with an iodonium salt and N-vinylcarbazole, the iron complex-based photoinitiating systems are able to generate radicals, cations, and radical cations. The initiation efficiency is investigated through real-time Fourier transform infrared spectroscopy and a satisfactory initiating ability is found. The mechanisms for the generation of the reactive initiating species through photoredox catalysis are studied by different methods (steady state photolysis, cyclic voltammetry and electron spin resonance spin trapping techniques) and discussed in detail. (C) 2016 Wiley Periodicals, Inc.
    Mots-clés : amine system, arene complex, atom-transfer, Cationic photopolymerization, epoxy polymerization, fragmentation chain transfer, iridium complexes, iron complexes, LEDs, n-vinylcarbazole, photoinduced electron-transfer, Photoinitiator, Photoinitiators, photopolymerization reactions, Radical photopolymerization.

  • Zhang, J.; Campolo, D.; Dumur, F.; Xiao, P.; Fouassier, J. P.; Gigmes, D.; Lalevee, J. Chemcatchem 2016, 8 (13), 2227-2233.
    Résumé : The novel role of metal-based complexes as photoinitiator catalysts fits well into the concept of green chemistry, as it realizes the activation of polymer synthesis processes by visible light that are abundant in the solar light and allows the marked reduction of photoinitiator amount in the systems. In the present paper, a series of iron complexes (FeC_x) with various ligands have been proposed as new photoinitiator catalysts to initiate the cationic polymerization of epoxides or the free radical polymerization of acrylates upon a near-UV or visible-light LED exposure. The ligands play an important role on the light absorption properties and the photoinitiation ability of the iron complexes. In combination with one or two additives, FeC_x are capable to efficiently generate radicals, cations, and radical cations through an oxidative or a reductive path. Two of the newly developed FeC_x-based photoinitiating systems exhibited comparable photoinitiation efficiency with the commercial TypeI photoinitiator bis(2,4,6-trimethylbenzoyl)phenylphosphineoxide (BAPO). Owing to the photocatalytic effect, remarkable photoinitiation efficiencies have been achieved by using very low concentration of iron complexes (0.02 wt%) in the systems. The involved photochemical mechanisms have been studied using electron spin resonance spin trapping, steady state photolysis, cyclic voltammetry, and laser flash photolysis techniques.
    Mots-clés : aldehydes, cationic-polymerization, Dyes, free-radical photopolymerization, green chemistry, iridium complexes, iron, ligand effects, n-vinylcarbazole, organocatalysis, photocatalysis, Photochemistry, Polymerization, solar-cells, versatile photoinitiators.

  • Zhang, J.; Campolo, D.; Dumur, F.; Xiao, P.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Polymer Bulletin 2016, 73 (2), 493-507.
    Résumé : A carbazole-bound ferrocenium salt [i.e., (eta(6)-Carbazole) (eta(5)-cyclopentadienyl) iron hexafluorophosphate-FS] is proposed as an efficient photoinitiator for the cationic ring-opening polymerization of epoxides under air upon the exposure to a near-UV LED at 385 nm or a visible LED at 405 nm. When using this ferrocenium salt FS (0.2 wt%)/diphenyliodonium hexafluorophosphate or FS (0.2 wt%)/diphenyliodonium hexafluorophosphate/N-vinylcarbazole, final epoxide conversions of 55-66 % can be obtained after 800 s of irradiation at 385 or 405 nm. Reference cationic photoinitiators (i.e., diphenyliodonium hexafluorophosphate; 9-(4-hydroxyethoxyphenyl) thianthrenium hexafluorophosphate and triphenylsulfonium hexafluorophosphate) are unable to initiate the epoxide polymerization under the same conditions. The photochemical mechanisms for the formation of the initiating species are studied using steady-state photolysis, cyclic voltammetry, laser flash photolysis and electron spin resonance spin-trapping techniques. Molecular orbital calculations help to describe the absorption properties and the initiation step. The performance attained when using FS alone is really promising for applications under soft near-UV or visible light-emitting diode irradiation.

  • Zhang, J.; Dumur, F.; Horcajada, P.; Livage, C.; Xiao, P.; Fouassier, J. P.; Gigmes, D.; Lalevee, J. Macromolecular Chemistry and Physics 2016, 217 (22), 2534-2540.
    Résumé : Photoinitiating systems consisting of a highly porous iron(III)-based metal-organic framework (MOF), an iodonium salt, and N-vinylcarbazole are developed to initiate the free radical promoted cationic polymerization of epoxides under air and the free radical polymerization of acrylates in laminate upon exposure to near UV (385 nm) or visible (405 nm) light-emitting diodes. These systems present a satisfactory initiating ability. Among the five tested iron carboxylate MOFs exhibiting different compositions and topologies, the flexible microporous iron(III) terephthalate MIL53 is particularly interesting, leading to a final conversion of 58% for the ring-opening polymerization of epoxides. This provides the possibility of designing MOF/polymer composite materials with enhanced mechanical properties through the in situ incorporation of the MOF structure during the photopolymerization process.
    Mots-clés : catalysis, Cationic photopolymerization, light, metal-organic framework, mil-100(fe), oxide, photocatalyst, Photoinitiator, Photoinitiators, Radical photopolymerization.

  • Zhang, J.; Dumur, F.; Xiao, P.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Journal of Polymer Science Part a-Polymer Chemistry 2016, 54 (9), 1189-1196.
    Résumé : The cations and radicals produced in aminothiazonaphthalic anhydride derivatives (ATNAs) combined with an iodonium salt, N-vinylcarbazole, amine, or chloro triazine initiate the ring-opening cationic polymerization of epoxides and the free radical polymerization of acrylates under LEDs at 405 or 455 nm. The photoinitiating ability of these novel photoinitiating systems is higher than that of the well-known camphor-quinone-based systems. An example of the high reactivity of the new proposed photoinitiator is also provided in resins for 3D-printing using a LED projector@405 nm. The chemical mechanisms are investigated by steady-state photolysis, cyclic voltammetry, fluorescence, laser flash photolysis, and electron spin resonance spin-trapping techniques. (C) 2015 Wiley Periodicals, Inc.

  • Zhang, J.; Xiao, P.; Dumur, F.; Guo, C.; Hong, W.; Li, Y.; Gigmes, D.; Graff, B.; Fouassier, J. - P.; Lalevee, J. Macromolecular Chemistry and Physics 2016, 217 (19), 2145-2153.
    Résumé : A series of conjugated polymers and oligomers previously used in organic photovoltaics and organic light-emitting diodes ( OLEDs) have been examined for the first time as photoinitiators of polymerization. They address the present and future challenges facing photopolymerization: requirement of high extinction molar coefficients, absorption over the whole visible spectrum, ability to easily withdraw or release electrons. Interestingly, these compounds initiate the cationic polymerization of epoxides or the free radical polymerization of acrylates upon exposure of the photocurable formulations to a LED emitting at 405 nm. Some of them can potentially operate under blue, green, or red laser diodes.
    Mots-clés : Acrylate, atom-transfer, bulk heterojunction, derivatives, design, epoxide, led, naphthalimide, organic solar-cells, Photoinitiator, photopolymerization, polymer, power-conversion efficiency, ptb7, radical polymerization.

  • Zielonka, J.; Zielonka, M.; VerPlank, L.; Cheng, G.; Hardy, M.; Ouari, O.; Ayhan, M. M.; Podsiadly, R.; Sikora, A.; Lambeth, J. D.; Kalyanaraman, B. Journal of Biological Chemistry 2016, 291 (13), 7029-7044.
    Résumé : Using high throughput screening-compatible assays for superoxide and hydrogen peroxide, we identified potential inhibitors of the NADPH oxidase (Nox2) isoform from a small library of bioactive compounds. By using multiple probes (hydroethidine, hydropropidine, Amplex Red, and coumarin boronate) with well defined redox chemistry that form highly diagnostic marker products upon reaction with superoxide (O2 arrange=stack.), hydrogen peroxide (H2O2), and peroxynitrite (ONOO-), the number of false positives was greatly decreased. Selected hits for Nox2 were further screened for their ability to inhibit ONOO- formation in activated macrophages. A new diagnostic marker product for ONOO- is reported. We conclude that the newly developed high throughput screening/reactive oxygen species assays could also be used to identify potential inhibitors of ONOO- formed from Nox2-derived O2. and nitric oxide synthase-derived nitric oxide.
    Mots-clés : biology, cancer, cells, disease, extracellular-superoxide, fluorescence probes, high throughput screening (HTS), in-vivo, NADPH oxidase inhibitors, NADPH oxidase, nitric-oxide, nox inhibitors, reactive nitrogen species (RNS), reactive oxygen, reactive oxygen species (ROS), superoxide ion, therapeutic targets.

  • Zivic, N.; Zhang, J.; Bardelang, D.; Dumur, F.; Xiao, P.; Jet, T.; Versace, D. - L.; Dietlin, C.; Morlet-Savary, F.; Graff, B.; Fouassier, J. P.; Gigmes, D.; Lalevee, J. Polymer Chemistry 2016, 7 (2), 418-429.
    Résumé : A series of naphthalimide derivatives containing tertiary amine groups (DNNDs) have been prepared. Some of these derivatives (e.g. DNND3, DNND4 and DNND5) exhibit interesting shifted absorption so that they can be utilized as versatile photoinitiators upon exposure to various violet and blue LEDs (385, 405, 455 and 470 nm). They are particularly efficient for the cationic photopolymerization of an epoxide and the free radical photopolymerization of an acrylate. The thiol-ene photopolymerization, as well as the synthesis of interpenetrating polymer networks (of epoxide/acrylate blend) IPNs, is feasible. Remarkably, the production of hydrogels can also be easily achieved using a DNND derivative after inclusion in a cyclodextrin cavity. The photochemical mechanisms have been comprehensively investigated by steady state photolysis, Electron Spin Resonance (ESR), fluorescence, electrochemistry and laser flash photolysis and discussed in detail.

CH - Chapitres d'ouvrage

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