Thesis (M.S.)--Rochester Institute of Technology, 2004. / Typescript. Includes bibliographical references (leaves 121-123).

Biaryl moieties are important structural motifs in many industries, including pharmaceutical, agrochemical, energy and technology. The development of novel and efficient methods to synthesize these carbon-carbon bonds is at the forefront of synthetic methodology. Since Ullmann’s first report of stoichiometric Cu-mediated homo-coupling of aryl halides, there has been a dramatic evolution in transition metal catalyzed biaryl cross-coupling reactions. Our work focuses on the discovery and development of an unprecedented reagent combination for metal-free cross-coupling. It is hypothesized that direct carbon-carbon bond formation occurs via a triaryl-λ3-iodane and that electrophile/nucleophile pairing is critical for success in the reaction. Proof-of-concept for this approach focused on the reaction between bromo 4-trifluoromethylphenyl (trimethoxybenzene)-λ3-iodane and potassium 3-fluorophenyltriolborate. The spectator ligand and counter ions are important parameters for both reactivity and selectivity of the aryl group transfer in this reaction. Moderate to good yields of biaryl products are obtained by this method. Experimental evidence supports the assertion of a metal-free cross-coupling reaction.

The purpose of this investigation was to study the possibility of using, as electrolyte for the deposition of aluminum, systems containing aluminum phosphate dissolved in fused borate and phosphate mixtures. Aluminum coated metals combine the mechanical properties of the base metal and chemical resistance of aluminum. Electroplating, gives an even and controlled thickness of coating and imparts corrosion resistance. Methods for the deposition of aluminum previously investigated have not been used commercially, to any extent. Electrodeposition of aluminum was attempted, most frequently from nonaqueous organic solutions and from fused mixtures. Aluminum halides, especially aluminum chloride, was the solutes most frequently used. It is known that aluminum oxide is peptized by aluminum chloride. Severe corrosion is expected on articles electroplated in the presence of aluminum chloride. In the present investigation, the use of aluminum halides was avoided. Aluminum phosphate was employed in the system 5Na₂O.10Li₂O.6B₂O₃ as well as in the eutectic mixture of sodium metaphosphate and sodium pyrophosphate. ln none of the investigations was an electrodeposit of aluminum obtained. Investigation of the borates-phosphate mixtures comprised determination of a "fluid range"-composition diagram of the sodium oxide-lithium oxide-boric oxide system. The "fluid range" is a temperature range from an upper value at which, on cooling, liquid becomes viscous, to a lower value at which the solid first appears. These data were plotted on composition diagram which appears as a limiting composition curve and two isothermal, fluid range-composition curves at 600 and at 660 °C. The limiting composition is expressed as the minimum content of the boric oxide which will eliminate all carbon dioxide from the boric acid and alkali carbonates mixture. The area encircled between the 660 °c, upper fluid range and the limiting composition curve is a composition region in which electrodeposition of solid aluminum may be possible. In this region, a mixture of the composition 5Na₂O.10Li₂O.6B₂O₃ was taken as the solvent for the aluminum phosphate, and the fluid range-composition curve of this mixture was determined. It was found that the addition of aluminum phosphate to the molten 5Na₂O.10Li₂O.6B₂O₃ has little effect on the fluid range up to 18.68 per cent by weight of aluminum phosphate. Because the fused electrolyte is very corrosive, its action on different containers was studied. These containers included those made of porcelain, nickel, ampco metal, armco iron, plumbago, graphite and platinum. Except for the graphite and the platinum, no material was suitable for use as a container. No aluminum was electrodeposited from the molten bath of 5Na₂O.10Li₂O.6B₂O₃ or from its solution with aluminum phosphate. Both aluminum anode and platinum cathode were covered with black deposits after electrolysis. The deposits were studied by chemical methods, spectrographical analysis and X-ray analysis. Final results showed that they consisted primarily of carbon. A search for the source of this carbon, formed in the electrodeposition, indicated that it came from the carbon dioxide absorbed from the air by the fused electrolyte. A mechanism for the reaction was proposed. Electrochemical properties of the electrolyte 5Na₂O.10Li₂O.6B₂O₃ as well as those of its solution with aluminum phosphate were studied. Both the molten 5Na₂O.10Li₂O.6B₂O₃ and the molten mixture of 9.4 per cent of aluminum phosphate and 90.6 per cent of 5Na₂O.10Li₂O.6B₂O₃ showed no decomposition potential on electrolyzing with aluminum anode and platinum cathode. If platinum electrodes were used for borates-phosphate system, the current was constant when stirred, when moisture was added, and when the electrodes were immersed periodically. The decomposition potential determined for the borates-phosphate system with platinum electrodes was about 1.40 volts, at 600 ± 10 °C. Qualitative electrodeposition tests showed that no aluminum could be deposited from either electrolyte. Quantitative electrodeposition test with the molten 5Na₂O.10Li₂O.6B₂O₃ showed that the weight loss of the aluminum anode consisted of both electrolytic loss and direct chemical attack. Also, a eutectic mixture of the sodium metaphosphate and sodium pyrophosphate was used as the solvent to dissolve aluminum phosphate for electrolysis. The molten mixture had a strong oxidizing power, the aluminum anode became passive, and a strong anode effect was observed, if an aluminum anode was used. Black coatings were formed on the copper cathode with either an aluminum anode, or an anode of an alloy of 75 per cent of aluminum and 25 per cent of copper, or a platinum anode. The black coating on the copper cathode was found by chemical analysis to be a copper compound. / Ph. D.

Le besoin accru de stockage d'énergie via Li- et batteries Na-ion nécessite une recherche continue de nouveaux matériaux de cathode ayant une densité énergétique plus élevée et étant sûr et durable. Ainsi, nous avons exploré des composés à base de borate capables de réagir avec Li/ Na-ions de manière réversible, soit par le biais de réactions topotactic- ou de conversion. Nous nous sommes concentrés sur les candidats avec des anions polyborate, qui devraient montrer des potentiels redox élevés par rapport aux matériaux à base BO3. Li6CuB4O10 utilisant comme composé modèle, nous avons montré la possibilité d'obtenir des potentiels d'oxydo-réduction de 4.2 et 3.9 V par rapport à Li pour l'α- et ß polymorphes. L'activité redox a été rationalisée par spectroscopie EPR et calculs DFT. Nous révélons en outre la relation structurelle / synthétique entre les deux polymorphes et montrons une conductivité ionique élevée de 1.4 mS / cm à 500 °C pour une forme de HT d'-Li6CuB4O10. De plus, nous avons pu préparer deux pentaborates 3d-métal nouveau sodium Na3MB5O10 (M = Fe, Co). M = Fe, nous avons observé une intercalation Na réversible à un potentiel moyen de 2.5 V par rapport à Na, alors Na3CoB5O10 avéré être inactif électrochimique. Dévier à partir de composés d'insertion / désinsertion classiques, nous avons étudié la électrochimique entraîné la réaction d'un oxyborate bismuth Bi4B2O9 contre Li par des mesures électrochimiques combinées avec XRD et TEM. Nous avons constaté qu'il est possible de faire défiler ce matériau réversible entre 1.7 et 3.5 V avec un potentiel redox d'environ 2.3 V par rapport à Li avec seulement 5% en poids de carbone et une faible polarisation ~ 300 mV. / The increased need of energy storage via Li- and Na-ion batteries requires a continuous search for new cathode materials having higher energy density and being safe and sustainable. Thus, we explored borate based compounds capable of reacting with Li/ Na-ions in a reversible way either through topotactic- or conversion reactions. We focused on candidates with polyborate anions, that are expected to show elevated redox potentials compared to BO3 based materials. Using Li6CuB4O10 as a model compound we showed the possibility to achieve redox potentials of 4.2 and 3.9 V vs Li for the α- and β-polymorphs. The redox activity was rationalized through EPR spectroscopy and DFT calculations. We further reveal the structural/ synthetic relation between the two polymorphs and show a high ionic conductivity of 1.4 mS/cm at 500°C for a HT form of α-Li6CuB4O10. Moreover we were able to prepare two new sodium 3d-metal pentaborates Na3MB5O10 (M = Fe, Co). For M = Fe we observed a reversible Na intercalation at an average potential of 2.5 V vs Na, whereas Na3CoB5O10 turned out to be electrochemical inactive. Deviating from classical insertion/ deinsertion compounds, we studied the electrochemical driven reaction of a bismuth oxyborate Bi4B2O9 versus Li through electrochemical measurements combined with XRD and TEM. We found that it is possible to reversible cycle this material between 1.7 and 3.5 V with an redox potential of ~2.3 V vs Li with only 5wt% carbon and a small polarization ~300 mV. Owing to the complexity of 3d-metal borate chemistry encountered through this PhD, the chances of having a borate based positive electrode for next generation Li-ion batteries is rather slim.

Le marché de la préservation du bois recherche des alternatives aux traitements anciens, efficaces mais généralement toxiques pour l'environnement comme pour l'Homme. L'étude propose d'évaluer l'amélioration de résistance biologique apportée par l'utilisation de borates combinés à des huiles végétales. Les borates reconnus pour leur efficacité biocide mais lessivés sont en partie retenus par l'ajout d'huile végétale, le tout forme un traitement efficace et à faible impact environnemental contre les champignons et les termites. Les combinaisons simples se sont avérées plus efficaces que les émulsions. La synthèse d'un sel d'ammonium borate oléate s'est également montrée prometteuse. L'amélioration des traitements à l'huile s'est en revanche montrée compliquée, l'impossibilité de fixer l'huile sur le bois, la sensibilité des huiles dégradées aux moisissures et la réaction au feu des bois huilés sont autant de facteurs limitant pour l'instant l'usage de ces traitements.

Graduation date: 1995

En vue d'application à l'éclairage ou dans les dispositifs de visualisation à plama, on a étudié la luminescence de l'ion Eu2+ dans les borates BaLnB9O16 (Ln = La, Ce, Gd, Y) et de l'ion Eu3+ dans les diverses phases des systèmes Gd2O3-P2O5 et Y2O3-P2O5. Des informations sur les structures des réseaux-hôtes lorsqu'elles étaient inconnues, ont pu être obtenues par diffraction X et spectroscopie Raman. Pour Ln = Y, Gd, les borates BaLnB9O16:Eu2+ présentent une émission dans le bleu stable...

This thesis covers the synthesis and the characterization of sodium lanthanide oxide phosphates, rare earth added strontium pyrophosphates and the Rietveld structural analysis of rare earth orthoborates. Solid state and microwave-assisted synthesis method was employed for the synthesis of desired materials. The formation of the produced phases was confirmed by X-ray Diffraction (XRD), Infrared FT-IR, Raman, Scanning Electron Microscopy (SEM) methods. By using Rietveld Refinement method, structural analysis of rare earth orthoborates were done and three dimensional crystal structures were found. In the first part of the thesis, some new sodium lanthanide oxide phosphates were synthesized by solid state reaction method from Ln2O3 (where Ln= La, Nd, Sm, Gd, Dy, Ho, Er, Yb), Na2CO3, NH4H2PO4 at 1100 oC. Na2LaOPO4, Na2NdOPO4, and Na2SmOPO4 produced with the space group is Pmm2. With the help of the same procedure new orthorhombic Na2DyOPO4, Na2HoOPO4, Na2ErOPO4, and Na2YbOPO4 were synthesized for the first time in the literature at 1100 oC with the same space group Pmm2. v In the second part of the thesis, Sr2P2O7 - ZrP2O7 solid solution was obtained by the solid state reaction and they were characterized for the first time in literature and subjected to thermoluminescence measurements showing Sr2P2O7 has glow curve around 100 oC. Then CuO and some rare earth oxides (Y2O3, La2O3, CeO2, Pr6O11, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Tb2O3, Dy2O3, Ho2O3, Er2O3, Tm2O3, Yb2O3, Lu2O3) 0.5-15% (by weight) were added to pure Sr2P2O7. After structural determinations by XRD, thermoluminescence studies showed two glow peaks of Pr, Ho, and Nd along with Cu-added samples, one of them is always at around 90 oC and the other TLthermoluminescence- peak around 180, 275, and 285 oC, respectively. This study showed that rare earth added Sr2P2O7 materials can be promising material for dosimetric applications. In the third part of this work, time saving microwave-assisted synthesis method was applied to produce pure LnBO3 (Ln=La, Nd, Dy, Ho) by using urea and sucrose as a microwave active organic additive. For LaBO3 and NdBO3, space group found as Pnma and for DyBO3 and HoBO3 powders crystallized in hexagonal unit cell with P-6c2 space group. All microwave-assisted products have particle sizes lower than 1 micrometer. In the final part of this study, pure LnBO3 (Ln=Y, La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu) powder samples were produced by using solid state reactions of Ln2O3 and H3BO3 (ratio=1:2) heated at 900 oC for 10 hours and 1000 oC for 5 hours. The crystallographic studies conducted with rietveld structural refinement and unit cell parameters, background functions, profile parameters, zero shift, atomic positions, and unisotropic thermal parameters were refined. LaBO3 and NdBO3 were solved based on Pnma orthorhombic structure while the crystal structure of YBO3, DyBO3 and HoBO3 were monoclinic C2/c. SmBO3 showed triclinic P-1 structure.

comme luminophore rouge dans les nouveaux dispositifs de visualisation à panneaux plasma ; le borate Li6(Y,Gd)(BO3)3: Ce3+ est particulièrement approprié pour la détection des neutrons. Outre les borates Li6Ln(BO3)3 (Ln = terre rare) et Li3Ln2(BO3)3 antérieurement connus, l'étude des diagrammes ternaires Li2O-B2O3-Ln2O3 a mis en évidence l'existence de quatre autres compositions : les borates Li3Ln(BO3)2 et les oxyborates LiLn6O5(BO3)3, LiLn2O2BO3 et<br />Li2Ln5O4(BO3)3. Chacune des structures a été résolue sur monocristal par diffraction des rayons X.<br />Une caractéristique des oxyborates est l'existence d'un assemblage de tétraèdres OLn4, tridimensionnel<br />dans les borates LiLn6O5(BO3)3 , bidimensionnel dans les phases Li2Ln5O4(BO3)3 et LiLn2O2BO3 , les groupes (BO3)3- et les ions Li+ se disposent dans des cavités ou entre les couches de ces sous-réseaux. Une étude de la luminescence des ions Eu3+, Tm3+ et Ce3+ a été effectuée afin notamment d'évaluer les performances de ces nouveaux matériaux en tant que luminophores ou scintillateurs. Pour la première fois dans des composés du bore, une luminescence de transfert de charge du lanthane et du cérium tétravalent a par ailleurs été observée.

Thesis (Ph. D.)--Institute of Paper Chemistry, 1964. / Bibliography: leaves 90-93.