Synthesis, X-ray crystal structures, electrochemistry and theoretical investigation of a tetradentate nickel and copper Schiff base complexes

International audienceNew tetradentate mononuclear nickel(II) [NiL] and pentadentate binuclear copper(II) [Cu 2 L 2 H 2 O], H 2 O Schiff base complexes have been synthesized. The crystal structures of [NiL] and [Cu 2 L 2 H 2 O], H 2 O have been determined by X-ray diffraction method showing distorted square-planar geometry for [NiL] and distorted tetragonal pyramid geometry for [Cu 2 L 2 H 2 O], H 2 O. In both complexes, the dehydroacetic acid functional group engages in a deprotonated manner and coordination occurs through the nitrogen atoms of the imine function and the phenolic oxygen. Density Functional Theory calculations are carried out for the determination of the optimized structures. The fundamental vibrational wave numbers are calculated and a good agreement between observed and calculated wave numbers is achieved

Etudes expérimentale et théorique des interactions entre sous-réseaux organique / inorganique dans des systèmes hybrides modèles

L étude réalisée au cours de cette thèse s inscrit dans le vaste domaine d études des matériaux hybrides inorganique/organique. A côté de l élaboration de matériaux hybrides modèles (Hydroxydes Doubles Lamellaires HDL [MII1-xMIIIx(OH)2]x+[Anx/n.mH2O]x- / anions aromatiques fonctionnalisés), ce travail se propose d aborder deux grands types d interaction de nature physique ou chimique respectivement associés aux aspects intercalation et greffage suite à un traitement thermique spécifique. Des systèmes modèles constitués de sels acides (p-hydroxybenzène sulfonate HBS, phydroxybenzoate HBC) intercalés dans des matrices minérales HDL ont été synthétisés par différentes méthodes de préparation (coprécipitation, échange ionique, synthèse hydrothermale). Après avoir caractérisé ces systèmes par des techniques classiques d investigation chimique et structurale (DRX, IR, ATG ), la démarche originale a été d utiliser la Spectroscopie Photoélectronique à Rayonnement X (XPS) comme sonde locale afin de mieux apprécier les transferts électroniques. Parallèlement, des calculs quantiques (de type moléculaire et/ou périodique) ont été menés pour chaque système dans une approche couplée expérience/théorie afin d'établir le caractère et la nature de l'interaction entre sous-réseaux inorganique et organique. Cette démarche couplée a permis d établir des éléments de comparaison entre les systèmes hybrides en fonction de la composition cationique de la matrice minérale HDL (Zn2Al, Cu2Cr) et du groupement fonctionnel anionique de la composante organique (-SO3-, -CO2-)This thesis concerns the large field of studies of inorganic/ organic hybrid materials. In addition of elaboration of model hybrid materials (Layered Doubles Hydroxides LDH [MII1-xMIIIx(OH)2]x+[Anx/n.mH2O]x- / functionalized aromatic anions), this work proposes to address two major types of interaction with physical or chemical nature associated with intercalation and grafting process after a specific heat treatment respectively. Model systems consisting of acid salts (phydroxybenzene sulfonate HBS, p-hydroxybenzoate HBC) intercalated in inorganic matrices LDH were synthesized by different preparation methods (coprecipitation, ion exchange, hydrothermal synthesis). After characterization of these systems by conventional method of chemical and structural investigation (XRD, IR, TGA ...), the original approach was to use the X-Ray Photoelectron Spectroscopy (XPS) as a local probe to best appreciate the electronic transfers. In parallel, quantum calculations (molecular and / or periodical type) were conducted for each system in a experiment / theory coupled approach to establish the character and nature of the interaction between inorganic and organic sub-lattices. This coupled method allowed to establish comparisons between hybrid systems as a function of the cationic composition of the mineral matrix LDH (Zn2Al, Cu2Cr) and as a function of anionic functional group of the organic component (-SO3-,-CO2-)PAU-BU Sciences (644452103) / SudocSudocFranceF

Crystal structure of (E)-4-hydroxy-3-{1-[(4-hydroxyphenyl)imino]ethyl}-6-methyl-2H-pyran-2-one

In the title Schiff base, C14H13NO4, which adopts the phenol–imine tautomeric form, the dihedral angle between the planes of the benzene and heterocyclic (r.m.s. deviation = 0.037 Å) rings is 53.31 (11)°. An intramolecular O—H...N hydrogen bond closes an S(6) ring. In the crystal, molecules are linked by O—H...O hydrogen bonds to generate C(11) chains propagating in the [010] direction. A weak C—H...O link is also observed, leading to the formation of R55(32) rings extending parallel to the (101) plane

(E)-4-Hydroxy-6-methyl-3-[1-(2-phenylhydrazinylidene)ethyl]-2H-pyran-2-one

The title compound, C14H14N2O3, crystallized with three crystallographically independent molecules (A, B and C) in the asymmetric unit. The three molecules each have an E conformation about the C=N bond but differ in the orientation of the phenyl and pyran rings. The dihedral angles between the phenyl and pyran ring planes are 14.30 (1), 28.38 (1) and 25.58 (1)° in molecules A, B and C, respectively. There is an intramolecular O—H...N hydrogen bond in each molecule with an S(6) ring motif. In the crystal, molecules are linked by N—H...O and C—H...O hydrogen bonds, forming layers parallel to (001), enclosing R22(8) and R33(21) ring motifs. The layers are linked via C—H...π interactions, forming bilayers, which are joined by a further C—H...π interaction, forming a three-dimensional structure

Thermal behaviors and grafting process of LDH/benzene derivative hybrid.

International audienceThermal behaviors of four hybrid layered double hydroxide (LDH) phases have been studied by thermogravimetric analyses coupled with mass spectroscopy, temperature dependence of X-ray powder diffraction measurements, and temperature dependence of infrared spectroscopy measurements. Inorganic zinc-aluminium LDH main layers (with a Zn2+/Al3+ cationic ratio of 2) inserted the following four organic anions: benzene carboxylate, 4-hydroxy-benzene carboxylate, benzene sulfonate and 4-hydroxybenzene sulfonate. The four LDH hybrids have been synthesized by the coprecipitation method. The as-prepared samples have been characterized and their compositions were determined. Thermal evolution of the crystalline phases during the dehydration (occurring before 200 ◦C) and the dehydroxylation (occurring between 200 and 300 ◦C) gave evidence for organic anion grafting onto the inorganic main layer. The thermal stability of the LDH hybrid system depends on the nature of the intercalated aromatic anion. The thermal grafting process can be monitored, as well as its thermal reversibility, by choosing the functionalizations of the benzenic anion and the temperature of the applied heat treatment

Influence of recasting on the quality of dental alloys: A systematic review

Équipe 401 : Nanomatériaux pour la vie et développement durableInternational audienceStatement of problem. Dental alloy manufacturers advise against the reuse of previously melted alloy. However, for economic reasons, dental laboratories often reuse the casting surplus (sprue and metal remaining in the crucible former). Such reuse remains a controversial topic in dental practice. Purpose. The purpose of this systematic review was to assess the effects of remelting dental alloys by evaluating the following parameters: reasons for recasting and associated processes, feasible number of recastings, treatment of alloys before recasting and its effects on cytotoxicity, color of opaque porcelain, castability of alloys, marginal accuracy, mechanical properties, porcelain-metal interfaces, and corrosion. Material and methods. The systematic review included all studies on dental alloy recasting. MEDLINE, Dentistry and Oral Science Source, Science Direct, and ISI Web of Science were searched (up to July 2014). Data were extracted and the quality of studies was assessed. Results. Thirty-four studies published between 1983 and 2014 were included. The number of recastings ranged from 1 to 10. The percentage of new alloy ranged from 0 to 100 wt%, although the mean value was 50 wt%. Conclusions. Evidence for the feasibility of adding 50% new metal at each recasting is limited. The number of recastings should be limited to a maximum of 4. No general test protocol can be deduced from these studies, which limits the comparison and exploitation of data. Furthermore, no consensus protocol exists for the evaluation of recasting. Future studies should work toward establishing a standard protocol

Spinel Magnetic Iron Oxide Nanoparticles: Properties, Synthesis and Washing Methods

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A multiscale structural study of nanoparticle films prepared by the Langmuir-Blodgett technique

Équipe 401 : Nanomatériaux pour la vie et développement durableInternational audienceArrays of magnetic nanoparticles (NPs) represent a very interesting challenge toward the development of new devices for magnetic applications such as data storage and spintronic. The final properties of such assemblies depending essentially on the spatial arrangement of NPs, it is of first importance to investigate precisely their structure. Here, the structure of monolayer and multilayer films of magnetic iron oxide NPs assembled by the Langmuir-Blodgett (LB) technique has been studied by usual techniques such as SEM, AFM and ellipsometry and by a new and an easy to process enhanced optical technique: the Surface Enhancement Ellipsometry Contrast (SEEC) microscopy. This technique is based on the use of a new generation of microscope slides used as substrates which allow the strong enhancement of the sample contrast to a point where it becomes possible to visualize the structure of monolayer and multilayer films at the nanoscale with a conventional optical microscope. The SEEC microscopy is demonstrated to be complementary to usual characterization techniques to study the structure of NPs films, especially for films containing very small nanosized NPs which are more difficult to analyze by usual techniques. While the film structure is investigated with lateral resolution of microns, the layer thickness is analyzed at the nanoscale (with a precision of 0.3 nm) with a close fit to the experimental measurements on local (AFM) and on larger (ellipsometry) areas. This technique presents the advantage to visualize directly the topography of NPs assemblies on very large areas by extracting information such as the height profile, the film roughness and generating 3D images

Rapid microwave synthesis of magnetic nanoparticles in physiological serum

International audienceAbstract Superparamagnetic Iron Oxide Nanoparticles (SPIONs) are more and more used in biomedical applications such as therapy (treatment for certain cancers, hyperthermia), diagnostic (contrast agent for Magnetic Resonance Imaging) or both. For these applications, SPIONs must be stable in an aqueous solution, monodisperse, with a narrow size distribution and without aggregation. To obtain these nanoparticles, a microwave process is carried out in this study as an easy, fast and reproducible synthesis method. Currently, in the literature, most synthesis of SPIONs are in ultra-pure water or another solvent. To consider the use of SPIONs in biomedical applications, it is essential to ensure the preservation of the physico-chemical parameters of the nanoparticles in the physiological medium to validate a synthesis process. With this objective, this study reports a comparison between the SPIONs synthesis in ultra-pure water and the SPIONs direct synthesis in a physiological serum (containing NaCl). To complete this comparison, the dispersion of SPIONs in physiological serum after an elaboration in ultra-pure water is reported. Characterizations of these different SPIONs samples are carried out to determine the physico-chemical parameters and magnetic properties. SPIONs are characterized by Transmission Electronic Microscopy, Dynamic Light Scattering, X-Ray Diffraction, Raman spectroscopy and magnetic measurements. Finally, to check if SPIONs can be used as contrast agent for MRI, a relaxometry measurement is performed

Diaquabis[4-(dimethylamino)pyridine-κN1]bis[2-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)acetato-κO1]cobalt(II)

In the mononuclear title complex, [Co(C10H6NO4)2(C7H10N2)2(H2O)2], the CoII ion is located on an inversion centre and has a distorted octahedral coordination geometry of type CoN2O4 by two N atoms from the two 4-(dimethylamino)pyridine (DMAP) ligands, two carboxylate O atoms from the two deprotonated N-phthaloylglycine (Nphgly) ligands [systematic name: 2-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)acetate] and two coordination water molecules. In the crystal, O—H...O, C—H...O hydrogen bonds and π–π stacking interactions link the molecules into the supramolecular structure