Gold octahedra nanoparticles (Au_0.03 and Au_0.045): Synthesis and impact on marine clams Ruditapes decussatus

The increased use of gold nanoparticles (AuNPs) in several applications has led to a rise in concerns about their potential toxicity to aquatic organisms. In addition, toxicity of nanoparticles to aquatic organisms is related to their physical and chemical properties. In the present study, we synthesize two forms of gold octahedra nanoparticles (Au_0.03 and Au_0.045) in 1.3-propandiol with polyvinyl-pyrrolidone K30 (PVPK30) as capping agent using polyol process. Shape, size and optical properties of the particles could be tuned by changing the molar ratio of PVP K30 to metal salts. The anisotropy in nanoparticles shape shows strong localized surface plasmon resonance (SPR) in the near infrared region of the electromagnetic spectrum. Environmental impact of Oct-AuNPs was determined in the marine bivalve, Ruditapes decussatus exposed to different concentrations of Au_0.03 and Au_0.045. The dynamic light scattering showed the stability and resistance of Au_0.03 and Au_0.045 in the natural seawater. No significant modification in vg-like proteins, MDA level and enzymatic activities were observed in treated clams with Au_0.03 even at high concentration. In contrast, Au_0.045 induced superoxide dismutase (SOD), catalase (CAT), glutathione transferase (GST) activities, in a concentration dependent manner indicating defense against oxidative stress. Enhanced lipid peroxidation represented by malondialdehyde content confirmed oxidative stress of Au_0.045 at high concentration. These results highlight the importance of the physical form of nanomaterials on their interactions with marine organisms and provide a useful guideline for future use of Oct-AuNPs. In addition, Vitellogenin is shown not to be an appropriate biomarker for Oct-AuNPs contamination even at high concentration. We further show that Oct-AuNPs exhibit an important antioxidant response without inducing estrogenic disruption

Synthèse et caractérisation de nanoparticules métalliques vers la nanomédecine

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Mise au point de nanosondes magnétiques chauffantes pour l'hyperthermie (synthèse, fonctionnalisation et évaluation de la puissance de pertes spécifiques)

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

Nouvelles phases hybrides dans les systèmes (M (élément de transition 3d, lanthanide ou cadium) - Carboxylate (succinate, malonate ou pyridine-2,5-dicarboxylate - Eau)

Plusieurs nouvelles phases ont été isolées et caractérisées dans les systèmes ternaires : M (Métal de transition 3d, lanthanide ou cadmium) Anion carboxylate (succinate, malonate, pyridine-2,5-dicarboxylate) - Eau. La plupart de ces composés ont fait l objet de déterminations structurales sur monocristal. Parmi les trois anions, seul l anion succinate favorise l obtention de composés hybrides ionrganique-organiques de structures plus compactes et donc des interactions Métal-Métal plus fortes : Trois nouveaux types structuraux ont été mis en évidence : Cu[O2C(CH2)CO2H]2.2H2O, [Cd][(O2C(CH2)2CO2)] [Cd(OH)]2[O2C(CH2)2CO2]. Les composés des éléments de transition 3d manifestent des comportements magnétiques diverses : ferromagnétisme, ferrimagnétisme ou anti-ferromagnétisme avec des températures d ordre faibles. Les mesures de la fluorescence dans le cas des composés aux terres rares mettent en évidence plusieurs résultats intéressants: (i) le temps de demi-vie est plus élevé pour les composés de symétrie triclinique en comparaison avec ceux de structure monoclinique, (ii) le dopage au samarium améliore nettement le temps de demi-vie, (iii) le transfert d énergie est très important dans le cas de Ce3+ Sm3+. Enfin l étude RMN a permis de mettre en évidence une corrélation entre déplacement chimique du 113Cd et le nombre de groupements hydroxyles premiers proches engagés dans le polyèdre de coordinance autour de ce cation.Several new phases were isolated and characterized in the ternary systems: M (3d transition metal, lanthanide or cadmium) - Anion carboxylate (succinate, malonate, pyridine-2,5-dicarboxylate) - Water. Most of these compounds were the object of structural determinations on single crystal. Among the three anions, only succinate facilitates the obtaining of hybrid inorganic-organic compounds with more compact structures and thus stronger Metal-Metal interactions. Three new structural types were put in evidence: Cu[O2C(CH2)CO2H]2.2H2O, [Cd][(O2C(CH2)2CO2)], [Cd(OH)]2[O2C(CH2)2CO2 ]. 3d transition elements led to compounds with various magnetic behaviours: ferromagnetism, ferrimagnetism or antiferromagnetism with weak magnetic interactions. The measures of the fluorescence in the case of rare earth compounds bring to light several interesting results: i) the half-life time is longer for the compounds of a triclinic symmetry in comparison with those of monoclinic structure, (ii) doping with the samarium improves significantly the half-life time, iii) the transfer of energy is very important in the case of Ce3+ Sm3+. Finally the study RMN allowed bringing to light a correlation between the 113Cd chemical shift and the number of hydroxyl groups engaged in the coordination polyhedron around this cation.PARIS13-BU Sciences (930792102) / SudocSudocFranceF

Les systèmes Na2CO3-(YbF3 ou YF3)-H2O (synthèse hydrothermale, études structurales et spectroscopiques)

Deux systèmes hydrothermaux, Na2CO3-W3-H20 (M=Yb, Y),.sont explorés par chauffage micro-onde à 190'C dans une large gamme de compositions. Trois phases nouvelles (Yb(CO3)(OH,F)-XH20, Na2M(CO3)2F, Na3M(CO3)2F2 (M=Yb, Y) Na4Y(CO3)2F3-H2O) sont mises en évidence dans chaque système. A T>190C, Na3Y(CO3)3-6H20, Na5y(CO3)4 et Nay2(CO3)3F apparaissent. En présence de Li2CO3, une seule phase cubique Na2LiLn(CO3)3 subsiste pour les deux systèmes, ainsi que pour la série des lanthanides Eu-Lu. Un désordre Na-'/Ln 3+ affecte trois des phases mentionnées, Na3M(CO3)2F2 (Yb, Y) et Na2LiLn(CO3)3. Dans Na2LiY(CO3)3, la RMN montre que Li+ est animé d'une agitation rapide dans son polyèdre de coordination. La comparaison des spectres RNIN 3Q-NUS de Na5Y(CO3)4 et Na2LiY(CO3)3 suggère une coordinence proche de 6 pour Na-' dans Na2LiY(CO3)3. La microscopie électronique indique, par ailleurs, que les structures de Na3M(CO3)2F2 (Yb, Y) présentent une modulation liée à l'empilement de feuillets [NaM(CO3)2F2].Two hydrothermal systems, Na2CO3-MF3-H20 (M = Yb, Y), are investigated by mierowave assisted synthesis in large concentration domains at 190'C. Three unknown phases are evidenced in each system: Yb(CO3)(OH,F).H20, Na2Yb(CO3)2F, Na3Yb(CO3)2F2; Na2Y(CO3)2F, Na3y(CO3)2F2. Na4Y(CO3)2F3.H20. At higher température, Na3y(CO3)3-6H20, Na5Y(CO3)4 and Nay2(CO3)3F appear. With Li2CO3, one cubic phase Na2LiLn(CO3)3 exists for both systems and for Ln = Eu- Lu. Na -1 /Ln 3+ disorder affects three of the mentioned phases: Na3M(CO3)2F2, (M = Yb, Y) and the famdy Na2LiLn(CO3)3- hi Na2LiY(CO3)3, NMR spectroscopy indicates that Li+ is only submitted to fast thennal motion in its coordination polyhedron. The comparison of 3Q-NIAS NMR results for Na+ in Na5Y(CO3)4 and Na2LiY(CO3)3 suggests a coordination number close to six for Na+ in Na2LiY(CO3)3- Electron microscopy indicates that the structures of Na3M(CO3)2F2 (M = Yb, Y) present a modulation related to the stacking of the [NaM(CO3)9F2],,,, (M = Yb or Y) layers.LE MANS-BU Sciences (721812109) / SudocSudocFranceF

Exploration des systèmes (ZrF4, ZrO2) / Ta2O5-amine-HF-(éthanol, eau) (études structurales, condensation par voie thermique)

La motivation principale de cette thèse concerne l'élaboration de fluorures hybrides à structure microporeuse tridimensionnelle (3D) autour des cations à charge élevée Zr4+ et Tas+. Un intérêt considérable est accordé à ce type de matériaux en raison d'applications possibles en catalyse, ONL ou stockage de gaz. L'étude des systèmes (ZrF4' Zr02 et/ou Ta20S)-amine (tren,gua, dabco)-HFaq,-éthanol a été conduite à l'aide de trois méthodes de synthèse différentes à moyenne et basse température : par voies micro-onde et classique en autoclave Parr (T = 190C), par évaporation lente (T = 50C) d'une solution fortement concentrée en acide fluorhydrique. Dix-neuf phases ont été isolées, seize sont maintenant identifiées dont treize sont originales. Les caractérisations structurales de huit nouveaux fluorozirconates hybrides ont été réalisées. Cinq fluorotantalates ont aussi été mis en évidence. L'intégralité des phases nouvelles qui ont été obtenues présente une dimensionnalité de la partie inorganique limitée à 1D. L'environnement dodécaédrique de Zr4+ dans les fluorozirconates hybrides OD et la bipyramide pentagonale pour TaF 7 sont originaux. Il en est de même pour les chaînes doubles (Zr2F 10)2- dans [H2dabco].(Zr2F lo)·1.5H20 et les trimères Ta3O2F16 dans les variétés a et b-[H3tren]2·(Ta3O2F16).F. Le suivi du comportement thermique par ATG et par thermodiffraction des rayons X de deux composés hydratés a été effectué. La déshydratation de [H3tren]2.(ZrF7)2.9H2O comporte trois étapes principales : les deux premières conduisent successivement à un intermédiaire trihydraté [H3tren]2·(ZrF7)2·3H2O à 60C puis à un monohydrate (H3tren]2·(ZrF7)2·H2O à 90C. Vers 285C une réaction de condensation des entités ZrF7 en dimères Zr2F12 intervient dans [H3tren]2·(ZrF6).(Zr2F12). L'évolution thermique de [H2dabco].(Zr2F10).1.5H2O, de structure 1D, aboutit à la phase anhydre [H2dabco].(Zr2F10) dont la structure a été déterminée de façon ab-initio sur poudre. Dans les deux cas étudiés, il est montré que les réactions premières de déshydratation sont réversibles et topotactiques. Il est montré enfin, que des molécules d'eau ou des ions fluorure libres peuvent être encapsulés de façon octaédrique par six groupements amine primaire protonée de deux cations [H3tren)3+. Nous avons tenté d'examiner par RMN de 19F l'environnement de ces ions fluorure dans les deux fluorotantalates a et b-[H3tren]2·(Ta3O2F16)·F.The aim of this work is the synthesis of hybrid fluorides with microporous 3D structures Zr4+ and Ta5+ cations. A considerable interest is devoted to these materials as a reason of possible applications in catalysis, non linear optics (NLO) or gas storage. The study of (ZrF4, ZrO2 and/or Ta2O5)-(tren, gua, dabco) amine-HFaq.-ethanol systems was undertaken at average and low temperatures : in solvothermal conditions with microwave or classical (Parr autoclave) heating (T = 190C), by slow evaporation (T = 50C) of a saturated solution in hydrofluoric acid. Nineteen phases were isolated, sixteen are now identified of which thirteen are original. The structural characterization of eight fluorozirconates was carried out, five fluorotantalates were also evidenced. All new phases have 0D or 1D dimensionnality of the inorganic part. A dodecahedral environment of Zr4+ in 0D hybrid fluorozirconate [H3tren]4.(ZrF8)3.4H2O and a pentagonal bipyramide TaF7 are original. Double chains (Zr2F10)2- in [H2 dabco].(Zr2F10).1.5H2O and Ta3O2F16 trimers in a and b-[H3tren]2.(Ta3O2F16).F are also original. The thermal behavior of two hydrates was investigated by TGA and X-ray thermodiffraction. Dehydration of [H3tren]2.(ZrF7)2.9H2O occurs in three steps and leads successively to the trihydrate [H3tren]2.(ZrF7)2.3H2O at 60C, and to the monohydrate [H3tren]2.(ZrF7)2.H2O at 90C. Above = 285C, a variation of Zr4+ coordination occurs together with a condensation reaction of two ZrF7 units to build Zr2F12 dimers in [H3tren]2.(ZrF6).(Zr2F12). The thermal evolution of the 1D fluorozirconate [H2dabco].(Zr2F10).1.5H2O, leads to the anhydrous phase [H2dabco].(Zr2F10) which structure was determined by ab-initio Rietveld method from X-ray powder diffraction data. It is shown that the first two dehydration steps of [H3tren]2.(ZrF7)2.9H2O and the dehydration of [H2dabco].(Zr2F10)·1.5H2O are reversible and topotactic. Finally, it is shown that water molecules or free fluoride ions can be encapsulated in an octahedral environment by six primary amine groups of two cations [H3tren]3+. The environment of these fluoride ions was tentatively examined by 19F.NMR spectroscopy.LE MANS-BU Sciences (721812109) / SudocSudocFranceF

Synthesis of hybrid Au-ZnO nanoparticles using a one pot polyol process

cited By 7International audienceIn this work, we report on the synthesis of hybrid Au-ZnO nanoparticles using a one-pot chemical method that makes use of 1,3-propanediol as a solvent, a reducing agent and a stabilizing layer. The produced nanoparticles consisted of Au cores decorated with ZnO nanoparticles. The structure and morphology of the nanoparticles were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray spectrometry (EDX) and Raman spectroscopy. Optical extinction measurements, combined with numerical simulations, showed that the Au-ZnO nanoparticles exhibit a localized surface plasmon resonance (SPR) clearly red-shifted with respect to that of bare Au nanoparticles (AuNPs). This work contributes to the emergence of multi-functional nanomaterials with possible applications in surface plasmon resonance based biosensors, energy-conversion devices, and in water-splitting hydrogen production

Synthesis of La2Mo2O9 powders with nanodomains using polyol procedure

International audiencePowders of oxide-ion conductor La2Mo2O9 presenting nanodomains were synthesized by using polyol processes. The influence of different process parameters on the structure and particles morphology was determined. By the classical polyol process, whatever the polyol solvent used (ethylene glycol, diethylene glycol, 1,2-propanediol and tetraethylene glycol) platelet particles with dimensions of few hundred nanometers long and around twenty nanometers thick were observed, as agglomerates of small sub-particles. Only with diethylene glycol, pure La2Mo2O9 was obtained, whereas with microwave assistance, ethylene glycol also leads to pure product. For both ethylene and diethylene glycol solvent, the microwave assisted process resulted in either agglomerates or desert roses conglomerates after heat treatments at 500 degrees C for 5 min or 2 h. Specific surface areas, ranging between 23 and 36 m(2) g(-1), have been measured for pure La2Mo2O9 powders

Synthesis of La2Mo2O9 powders with nanodomains using polyol procedure

International audiencePowders of oxide-ion conductor La2Mo2O9 presenting nanodomains were synthesized by using polyol processes. The influence of different process parameters on the structure and particles morphology was determined. By the classical polyol process, whatever the polyol solvent used (ethylene glycol, diethylene glycol, 1,2-propanediol and tetraethylene glycol) platelet particles with dimensions of few hundred nanometers long and around twenty nanometers thick were observed, as agglomerates of small sub-particles. Only with diethylene glycol, pure La2Mo2O9 was obtained, whereas with microwave assistance, ethylene glycol also leads to pure product. For both ethylene and diethylene glycol solvent, the microwave assisted process resulted in either agglomerates or desert roses conglomerates after heat treatments at 500 degrees C for 5 min or 2 h. Specific surface areas, ranging between 23 and 36 m(2) g(-1), have been measured for pure La2Mo2O9 powders