The focus of this work is to synthesize and immobilize novel rigid tetraphosphine linkers via the formation of phosphonium groups and by direct adsorption of tetraphosphine salts on oxide surfaces. These methods offer the possibility to study the mechanism of the phosphonium formation in more detail by utilizing solid-state NMR spectroscopy. It has also been a point of interest to study the linkers and catalysts under realistic conditions, in the presence of solvents. Therefore, HRMAS (high-resolution magic angle spinning) NMR spectra of several phosphonium salts, adsorbed on SiO2, have been studied. This technique allows one to probe the leaching and mobility of the linkers on the surface. The mobilities of the linkers and the catalysts are crucial factors for the performance and design of the immobilized catalysts. Finally, since the exact mode of binding to the surface is unknown and is being discussed in the literature, for example, as hydrogen bonding between the F atoms in BF4- and surface silanol protons, the influence of the counteranion on the binding of phosphonium salts on silica surfaces is of utmost interest. For surface mobility studies a monolayer of phosphonium salts on the silica surface, both without solvent and in the presence of solvent, has been studied via 31P and 2H CP/MAS and HRMAS. Our findings show that the integrity of the tetraphosphine scaffold linkers is based upon how it is immobilized. The best system is formed when the phosphine is immobilized on the SiO2 support by adding Cl(CH2)3Si(OEt)3 to the reaction mixture. In this way, phosphonium salts are obtained, which are bound to the surface irreversibly by electrostatic interactions, as proven by solid-state NMR. In addition, leaching and mobility studies prove that the solvents play a crucial role, and the more polar solvents, such as DMSO, lead to the most extensive leaching due to the solvents' strong adsorption on the SiO2 surface. Leaching studies also show that the counteranion has an influence on the binding of the phosphoniumn salts on the SiO2 surface. The leaching proceeds in the following manner: BF4- > I- > Br- > Cl-. This is an indication that there is an additional interaction between the anion and, most probably, the surface silanol protons.

<p> This thesis describes the development of the Wittig olefination reaction of stabilized, semistabilized allylic trialkylphosphorus ylides with various aldehydes to afford E olefins mainly (E>89%). Since the steric demand of trialkylphosphorus ylides was decreased, aldehydes achieved high E selectivity. On the other hand, predominant or exclusive formation of Z olefms was achieved by using allylic triphenylphosphorus ylides and aromatic aldehydes like benzylaldehyde, while the combination of allylic triphenylphosphorus ylides and such sterically hindered aldehydes as cyclohexanecarboxaldehyde led to E olefm formation upon ylide formation with LiHMDS. In the case of olefination reactions of aldehydes with dimethyl thiazole ylide, it was shown that among the aromatic aldehydes only 4-nitrobenzaldehyde reacted with this ylide and provided a pure E olefin product (41% yield). Dimethylmalonyltributylphosphorane (DMTP) reacted with aromatic aldehydes in toluene at 125 °C to give the corresponding alkenes. 4-Nitrobenzaldehyde· gave the alkene in a much higher yield (81%), followed by 4-chlorobenzaldehyde (31%). With benzaldehyde, the corresponding olefin was isolated in only 14% yield under these conditions. Clearly, this highly stabilized ylide only enters into reaction with electron deficient aldehydes. A possible approach to Z-a, P-unsaturated aldehydes was investigated through the olefination of an acetal-ylide followed by hydrolysis. However, E acetal olefins were in fact isolated from this 2'-(1,3-dioxolanyl)-triethylphosphorus ylide with aromatic aldehydes in good yields (62%-76%). This result is still mechanistically interesting in view of the chemoselective formation of such an ylide in the presence ofthree ethyl substituents on phosphorus. </p> <p> Class of flavonoids: Sakuranetin, Naringenin and (28)-7-methoxy-6hydroxyflavanone, have been isolated from the diseased bark of Prunus sp. The structures were elucidated based on the spectroscopic data. Locations of 4-keto, 5-0H and 7-methoxy were deduced from COSY and HMBC spectra. Such compounds are of interest for their potential antibiotic activity against vancomycin-resistant strains of microbes. </p> / Thesis / Master of Science (MSc)

No / Phosphonium tosylates have been investigated as solvents for the Diels¿Alder reactions of isoprene with methyl acrylate, but-3-en-2-one and acrylonitrile. The reactions with oxygen-containing dienophiles showed high regioselectivity. Graphic

Ce travail de thèse réalisé à l’Institut de Chimie Moléculaire de l’Université de Bourgogne et en collaboration avec le PET Research Centre, porte sur la synthèse d’une nouvelle classe de pinces à fluorures dérivés d’aminoacides dans le but de piéger les ions [18F]-fluorures par formation d’une liaison B-F et d’évaluer leur potentiel en tant qu’agent d’imagerie TEP. Les travaux ont tout d’abord concerné la conception, la synthèse et la caractérisation des nouveaux sels de phosphoniums boronatés et trifluoroborates dérivés d’aminoacides. Ainsi, par quaternisation de l’o-boronate phényl phosphine avec des β-iodo amino esters ou des γ-iodo amino esters, les sels correspondants sont obtenus sans racémisation et avec des rendements atteignant 88%. La saponification des phosphoniums boronatés aminoesters donne les dérivés avec la fonction acide libre, tandis que l’acidolyse par HCl mène à l’amine correspondante offrant ainsi, l’opportunité d’un couplage ultérieur à une biomolécule. Ensuite, les dérivés trifluoroboratés sont facilement préparés par réaction de KHF2 en solution dans un mélange hydroalcoolique. Les études de stabilités en milieux aqueux des phosphoniums o-trifluoroborates aminoacides ont permis d’établir que ces dérivés sont extrêmement stables à l’hydrolyse. Enfin, la [18F]-radiosynthèse des sels de phosphonium boronatés a été étudiée selon deux méthodes: par échange isotopique 18F-19F direct à partir d’un trifluoroborate et par marquage direct d’un sel de phosphonium boronaté en présence d’un mélange de fluorures [18F] et KHF2. Intéressement, après une synthèse totale de 50 minutes comprenant le séchage azéotropique, la synthèse et la purification, [18F]-203c a été obtenu avec un rendement radiochimique de 10% corrigé de la décroissance, une pureté radiochimique ≥97% et une activité spécifique de 0.13 GBq/µmol. / This thesis project, which is part of a collaboration between the Institut de Chimie Moléculaire de l’Université de Bourgogne and the Positron Emission Tomography Research Centre, is about the synthesis of fluoride pincers derived from amino acids based on 18F-B bond construction to get a new class of PET imaging agents. First, this project concerned the design, synthesis and characterisation of new boronato and trifluoroborato phosphonium amino acid salts. Quaternisation of o-boronate phenyl phosphine with β-iodo amino esters or γ-iodo amino ester leads to the corresponding salts without racemisation and in yields up to 88%. Saponification of boronato phosphonium amino esters afford the free carboxylic acid derivatives, whereas HCl acidolysis leads to the corresponding amino compounds which offers the opportunity of further biomolecule coupling. Then, o-trifluoroborate phosphonium salts are efficiently prepared by reaction with KHF2 in solution on hydroalcoholic mixture. The kinetic stabilities of these o-trifluoroborate phosphoniums have shown extremely stable compounds to hydrolysis. Finally, [18F]-radiosyntheses of phosphonium salts was studied according to two methods : by 18F-19F isotopic exchange from trifluoroborate or by carrier added preparation of [18F]-fluoride ions from boronate phosphonium salts. Satisfactingly, after a total synthesis of 50 minutes (including azeotropic drying, synthesis and purification), [18F]-203c was obtained with a RCY on 10% decay corrected, a RCP ≥ 97% and a specific activity of 0.13 GBq/µmol.

Two series of stable palladium and silver complexes ligated to hemilabile ligands were prepared. The stability and applicability of these well-defined complexes in promoting various reactions (cycloaddition, hydroamination, cross-coupling reactions, etc.) was investigated. Structure-activity studies with a series of related ligands led us to find a pronounced ligand effect on these reactions. The dichotomous reactivity of triethyl phosphonium hydrobromide salt with dialkyl acetals was used for the synthesis of alkoxy phosphonium salts. Reactivity and applications of these phosphonium salts were described for the synthesis of the biologically active cinnamyl triazoles and ethyl indole-2-carboxylates. Total synthesis of the natural product nostodione A, was developed in eight chemical steps and with 21.6% overall yield from ethyl-2-indolecarboxylates. The synthesis of a mini-panel of structural analogs allowed for the discovery of anti-parasitic biological activity of nostodione A and its analogues for the first time. / Thesis / Doctor of Science (PhD)

No description available.

The potential use of Resadiye/Tokat bentonite as a reinforcement in polypropylene (PP) and linear low density polyethylene (LLDPE) polymer matrix nanocomposites filler was investigated. At first, organoclays (OC) were prepared by cation exchange reaction (CER) between the raw bentonite (RB) and three quaternary ammonium salts with long alkyl tails (QA): hexadecyl trimethyl ammonium bromide [HMA] [Br], tetrabutyl ammonium tetrafluoroborate [TBA] [BF4], tetrakisdecyl ammonium bromide [TKA] [Br] and one quaternary phosphonium (QP) salt: tetrabutyl phosphonium tetrafluroborate [TBP] [BF4]. Characterization of resulting materials by XRD, TGA, FTIR and chemical analysis confirmed the formation of organoclays. Ternary composites of PP/organoclay/ maleic anhydride grafted polypropylene (MAPP) were prepared with two different grades of PPs in a co-rotating twin screw extruder. Composites prepared with these organoclays and PPs showed microcomposite formation. In the second part of the study, raw bentonite was purified by sedimentation, and characterization of purified bentonite (PB) by XRD, cation exchange capacity (CEC) measurement and chemical analysis (ICP) confirmed the success of purification method. PB was then modified with two QA`s: dimethyl dioctadecylammonium chloride [DMDA] [Cl], tetrakis decylammonium bromide [STKA] [Br] and one QP: tributyl hexadecyl phosphonium bromide [TBHP] [Br]. Organoclays from PB were used with the PP with lower viscosity, and ternary nanocomposites (PP/Organoclay2/MAPP5) were prepared in the extruder followed by batch mixing in an intensive batch mixer. Use of DMDA and TBHP OCs resulted in nanocomposite formation, while STKA resulted in microcomposite formation as observed by XRD and TEM. Young`s modulus and yield stress of the samples were enhanced through nanocomposite formation. In the last part of the study, ternary composites of LLDPE/Organoclay/ compatibilizer, a random terpolymer of ethylene, butyl acrylate and maleic anhydride (E-BA-MAH, Lotader&reg / 3210), were prepared by melt compounding in the batch mixer at two different clay concentrations (2 and 5 wt %) and fixed compatibilizer/organoclay ratio (&alpha / =2.5). A commercial organoclay, I34, was also used in LLDPE based nanocomposites to make a comparison. XRD and TEM analyses of the compounds prepared by DMDA and TBHP showed mixed nanocomposite morphologies consisting of partially intercalated and exfoliated layers. Young`s modulus and tensile strength of nanocomposites prepared with DMDA and TBHP showed generally higher values compared to those of neat LLDPE, while results were the highest in the composites prepared with commercial organoclay I34. Parallel disk rheometry was used as a supplementary technique to XRD, TEM and mechanical characterizations, and it was shown to be a sensitive tool in assessing the degree of dispersion of clay layers in the polymer matrix.

Un récent rapport de l’OMS met en garde les autorités de santé sur l’émergence de résistances chez les bactéries et le développement de souches bactériennes multi-résistantes aux traitements antibiotiques actuels. La progression de ces phénomènes est dû à différents facteurs. L’environnement hospitalier concentre un usage important de traitements antibiotiques et représente ainsi un terreau favorable au développement de résistances chez les bactéries. Le staphylocoque doré, ainsi que sa souche résistante (SARM), s’avèrent problématiques et entraînent un grand nombre de maladies nosocomiales. Dans ce contexte, il est primordial de mettre au point de nouveaux agents antibactériens permettant de lutter contre ces bactéries. Les liquides ioniques (sels à point de fusion bas) démontrent d’importantes propriétés antibactériennes. Néanmoins les mécanismes de cet effet bactéricide n’ont pas encore été établis. Ainsi nous nous proposons, dans un premier temps, de synthétiser des liquides ioniques di-cationiques afin d’étudier les différents facteurs structuraux qui régissent leur activité antibactérienne. Dans un second temps, nous concevrons des liquides ioniques à base de phosphoniums fonctionnalisés avec une sonde fluorescente. En exploitant les propriétés spectroscopiques, nous tenterons d’observer leurs interactions avec les cellules bactériennes. Enfin, nous nous proposons d'utiliser les phosphoniums comme agents de fonctionnalisation de surface dans le but de mettre au point des surfaces aux qualités bactéricides intrinsèques. Pour ce faire nous utiliserons différentes méthodes comme la conception de monocouches auto-assemblées ou l’électropolymérisation. / A recent WHO report warns the health authorities about the emergence of new bacterial resistances and the development of multi-resistant strains against current antibiotics treatments. The growth of those resistances is due to several factors. The hospital environment concentrates a significant use of antibiotics and disinfectant representing a favorable ground for bacterial resistance development. Among them the Staphylococcus aureus and its methicillin resistant strain (MRSA) represent a crucial issue in care environments and is a major cause of hospital acquired infections. In this context, it is essential to develop new antibacterial agents to fight against these bacteria. Ionic liquid are low melting point salts, they show significant antibacterial properties. However, the fact that the mechanisms of action of their bactericidal effect have not been established yet constitutes a major obstacle to their development as bactericidal agents. Thus, we propose to synthetize ammonium- and phosphonium-based di-cationic ionic liquids in order to study the different structural factors that govern their antibacterial activity. Then we will develop phosphonium based ionic liquids functionalized with a fluorescent probe. By taking advantage of their spectroscopic properties we will try to observe their interactions with bacterial cells. Finally, we propose to use the phosphonium salts as surface functionalization agents in order to design surfaces with intrinsic antibacterial properties. To do so, we will use innovative methods such as conception of self-assembled monolayers or electropolymerization technics.