INORGANIC CHEMISTRY (2)

Author: LARA LOPEZ CARLOS JAVIER.
Year: 2005.
University: AUTÓNOMA DE MADRID [www.uam.es].
Place of defense: INSTITUTO DE CERÁMICA Y VIDRIO.
Place of preparation: INSTITUTO DE CERAMICA Y VIDRIO.

Summary: This thesis has been designed and developed a series of compositions that represent a new family of materials vitrocerámicos belonging to the systems MgO-BaO-SiO2 and ZnO-BaO-SiO2 for sealing IT-SOFC configuration flat. The work ranges from identifying the areas of glass formation in both systems, not studied in the literature so far, to the characterization of the glass and vitrocerámicos and its relevant properties. Following the thermal characterization and diltométrica of glassy initial compositions, we selected three compositions that met two of the most important requirements, a CTE between 10-12x10 -5 K-1, and a good introduction to the process of sintering and crystallization, so in principle should lead to stamps dense and homogeneous. With these glasses were studied curves viscosidad-temperatura and electrical properties in the working conditions of the stack, oxidizer and reductive. It was also addressed in-depth study of the crystallization process to characterize the mechanisms operating in each composition as a function of particle size, temperature and heating rate. This study, conducted in collaboration with the LaMaV of Sao Carlos, Brazil, revealed on the crystallization kinetics and compared with the kinetics of sintering, to optimize the conditions under seal, always respecting the working conditions of the stack. After obtaining stamps crystallized homogeneously dense and has been studied chemical compatibility of the same versus different substrates candidates for the interconnector, and the electrolyte, the operating conditions of the stack. Recent trials relating to the determination of oxygen permeability compared with genetic stamps, as measured in terms of pressure gradients, verifying that these materials are suitable for use as seals of solid oxide fuel cell configuration flat.

Author: Soriano Portillo Alejandra.
Year: 2006.
University: VALENCIA [www.uv.es].
Place of defense: Facultad de Química.
Place of preparation: Facultad de Química.

Summary: In this paper, thesis, we have prepared the following types of materials: 1) We have developed a new method for preparing magnetic nanoparticles, cobalt, nickel and palladium encapsulated in apoferritina which is the frame of a natural protein called ferritin. 2) There has been processing in thin films using the technique of Langmuir- Blodgett of magnetic nanoparticles of various derivatives of the natural ferritin. 3) has been prepared in the form of crystals new hybrid materials of molecular basis on which we combine two physical properties of interest. So, have combined magnetic anionic networks based on oxalate ligand with a cation type [Fe (sal2trien)] + ((sal2trien) = C14N4OH22), which provides transition from spin and two cations of the type [X (bzq) 2phen ] + (X = Go, Go) and [Rh (ppy) 2bpy] +, which are chiral and have luminescent properties.

Author: DÍAZ AUÑÓN JOSÉ ANTONIO.
Year: 2006.
University: ALICANTE [www.ua.es].
Place of defense: FACULTAD DE CIENCIAS.
Place of preparation: UNIVERSIDAD DE ALICANTE.

Summary: The heterogeneización metal complex used in homogeneous catalysis is an alternative that aims to combine the advantages of heterogeneous catalysis and the homogeneous catalysis. The aim is to achieve a catalyst using activated charcoal as a medium, which possess catalytic properties similar or superior to those of the compound when used under homogeneous and also is reusable successive times without substantial loss of catalytic activity. This is known as "Catalysts Hybrids." Amina has been synthesized and phosphine complexes of rhodium and palladium-amine. With complexes synthesized hybrid catalysts were prepared by three different methods of heterogeneización: physical adsorption, ion exchange and covalent bond. They have shown to be active in hydrogenation reactions and hidroformilación of olefins in liquid phase, in some cases they remain more active than the homogeneous catalysts. Moreover were obtained for both types of reactions, catalysts that were reusable successive times, reaching the goal set for the proposition. The conclusions of the thesis is as follows: * The activated carbons are appropriate media for obtaining hybrid catalysts complex Pd and Rh. * In hydrogenation reactions, anchoring by physical adsorption is effective catalysts remain stable. The covalent bond produces an effective anchor of the complex, obteniéndose stable catalysts, and reusable assets.

Author: VALLES CALLIZO CRISTINA.
Year: 2006.
University: ZARAGOZA [www.unizar.es].
Place of defense: INSTITUTO DE CARBOQUIMICA.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: The main purpose of this thesis was to reach control of the variable parameters that characterize the CVD method to achieve an optimization process that allows selectivity of production to a certain type of material formed by CNTs. You get a massive production of MWNTs with low metal content, using sol-gel catalysts supported on MgO. In this regard, it has been found that the addition of Mo to a sol-gel catalyst comprising Co. supported on MgO presents a significant impact on the production of MWNTs both on the structural characteristics of the materials obtained, as on the activity of catalysts, increasing yields of the reactions by increasing the content Mo arriving even up to a performance of a 4000% when the relationship Mo. / Cor is 30. It has been concluded, based on the results obtained, that the species Co. are the active parts of the catalyst, showing a selectivity towards the formation of CNTs rather than amorphous carbon being thus shown that Mo is not only a promoter and nuclea growth of the CNTs. It has tested the activity of several catalysts sol-gel synthesized with different transition metals and binary mixtures of them, doped with a high amount of Mo and supported MgO. All of them have proved to be very active in the production of carbon nanotubes wall multiple low grafitización of a wall and with a high yield, with the exception of Ytrio, which has proved to be completely inactive in the production of CNTs. It has been found that reducing both the relationship Mo. / Cor like (Mo + Co) / MgO catalyst in the sol-gel Mo-Co/MgO during its preparation process, we arrive at a better dispersion of the particles in the metal Support catalytic surface, resulting in a selectivity towards the production of carbon nanotubes with very small diameters and with a limited number of walls, mainly of two walls (DWNTs, double-walled carbon nanotubes), and three walls (TWNTs, triple-walled carbon nanotubes) following the breakdown of methane on them. For the production of HCNTs and Y-CNTs, has been introduced as a sulfur additive in the system. On the one hand, has been introduced in the catalyst endured during the sol-gel process and preparation, so alternative for the growth of reaction tubes. The sample of MWNTs from catalytic Co. has been subjected to a post consisting of a treatment oxidative CO2. This treatment does not alter the structure of MWNTs organized in large bundles which presented the original sample, but increases the degree of grafitización of tubes that compose it. This observation has been linked to the elimination of amorphous carbon in the sample and / or opening or exfoliation of the tubes. According to the results obtained shows that the BET surface area of the sample is not changed practically with this treatment, while there is a clear decline in the adsorption of H2, which suggests that activation of this treatment is not effective in improving storage capacities of such samples. As a general conclusion, we can say that these post-tratamientos activation, mainly chemical activation with KOH and treatment oxidative air increase, a remarkable way, the hydrogen adsorption capacity of up to achieve even interesting values ( a 1.81% by weight). These values still quite far from 6.5% minimum set by the DOE (Department of Energy of USA), necessary for automotive applications.

Author: ESCUDERO BELMONTE ALBERTO.
Year: 2006.
University: SEVILLA [www.us.es].
Place of defense: INST. DE CIENCIA DE MATERIALES DE SEVILLA.
Place of preparation: INSTITUTO DE CIENCIA DE MATERIALES DE SEVILLA - DEPARTAMENTO DE QUÍMICA INORGÁNICA.

Summary: STUDY OF CHEMISTRY OF SOLID STATE SYSTEMS Lu2Si2O7 - Y2Si2O7; Sc2Si2O7 - Y2Si2O7; Sc2Si2O7 - Lu2Si2O7

Author: CRESPO SOLANA EULALIA.
Year: 2006.
University: AUTÓNOMA DE BARCELONA [www.uab.es].
Place of defense: Departament de Química, UAB.
Place of preparation: INSTITUTO DE CIENCIA DE MATERIALES DE BARCELONA (ICMAB-CSIC).

Summary: The special properties of anionic boron clusters has led us to use them as doping agents in Organic Conducting Polymers, a kind of materials with a wide range of applications in different technological fields. The cobaltabisdicarbollide anion, [Co(C2B9H11)2]- was the first carborane used as a polypyrrole doping agent. The new material, PPy/[Co(C2B9H11)2], increased the overoxidation resistance limit and it showed a good stability 8 with reg eb1 ard to the redox switching. In this Thesis we have used this anion and other boron clusters as dopants of polypyrrole (PPy) to learn on their influence in the properties of the new materials to ease the surface functionalization, for their use as sensor supports and to facilitate their study by different techniques. In general, boron clusters improve the overoxidation resistance limit of polypyrrole materials, they delay the degradation process when a polypyrrole material is subject to a high anodic potential for a long time. By synthesizing polypyrrole materials doped with functionalized metallocarboranes, boranes and carboranes, and measuring the overoxidation resistance limit (ORL) of each one, we have been able to relate the ORL value with structural, electronic and hydrophobic properties of the dopant. We have established that the most stabilizing anions are those with a peanut or anchor shape, low charge density and polyether side-arms. XPS analyses have demonstrated that the shape of the anion is a fact to point up. The large number of boron atoms in these PPy materials has permitted to study for the first time the in-depth distribution of the anion in the material by XPS analysis during the overoxidation process. A dopant expulsion from the inner layers of the material has observed and in the particular case of anchor shape anions a built-up of the doping anion takes place in the electrolyte near surface area. Self-doped polymers, which have the cobaltabisdicarbollide anion, [Co(C2B9H11)2]-, covalently grafted to polypyrrole chains have been synthesized. Their behaviour against the overoxidation is completely different to the conventional PPy/A- materials. A post-overoxidation self-recovery has been described for the first time. We refer under this name the spontaneous capacity of an electroactive material to recover its electroactivity after having been subjected to an insulting potential so that its electroactivity was nought. It seems that an anion covalently grafted to polypyrrole and having the properties of the metallacarborane is a requirement to observe this self-recovery property. With the aim to create a cobaltabisdicarbollide anionic surface layer on top of a polypyrrole material doped with classical anions (PF6-) we have studied the functionalization of polypyrrole surfaces. Two different routes have been used: the functionalization post-polymerization and the design of bilayers. When the new material surface functionalized is obtained, the anionic layer interacts with specific cations such as methylene blue. The last part of this Thesis is focused on the application of polypyrrole doped with cobaltabisdicarbollide in the design of biosensors, as a platform for developing immunosensor devices and Cu(II) or K+ ion selective electrodes. The ability to create materials with well-controlled structures at the nanometer scale is of intense interest for biomedical devices. For that purpose polypyrrole doped with cobaltabisdicarbollide has been electropolymerized on gold substrates modified with SAMs to get nanoring structures.

Author: SANCHEZ VEGA MARIA GABRIELA.
Year: 2006.
University: OVIEDO [www.uniovi.es].
Place of defense: FACULTAD DE QUIMICA.
Place of preparation: FACULTAD DE QUIMICA.

Summary: The present report describes the efficient synthesis of a family cluster carbonílicos of ruthenium and osmium several nuclearidades those who have joined carbenos N-heterocíclicos (CNHs) with different characteristics such as terminal ligands. The preparation of these compounds is accompanied by studies of its reactivity and thermal stability. The latter have shown that CNHs coordinated on clusters may suffer activation processes relevant links CH and CN showing that these compounds are not very stable at moderate temperatures. The mechanism of one of these processes has been established by analyzing its surface potential energy through Functional Theory of Gravity. The synthesis of such compounds as the reactivity studies undertaken are unprecedented.