La primera parte de la tesis se dedica al estudio del mecanismo de una reacción de activación C-H por un complejo de niobio. Se racionalizó el mecanismo de activación de enlaces C-H del benceno por el complejo TpMe2NbCH3(c-C3H5)(MeCCMe). El intermedio clave es un complejo inusual de 2-ciclopropeno. Conseguimos también racionalizar las selectividades obtenidas para la activación de varios alquilaromáticos por el complejo de niobio 2-ciclopropeno. También se investigó el papel del ligando alquino en estos complejos y su posible papel en procesos de migración de ligandos. En la segunda parte de la tesis, se investigaron las reacciones de acoplamiento cruzado con reactivos basados en silicio. Los resultados sugieren que la transmetalación es más fácil después de la disociación de la fosfina, o cuando un ligando bromuro está coordinado al paladio. El efecto beneficioso de la dibencilidenoacetona en el acoplamiento también fue aclarado. / The first part of the thesis is mainly devoted to the mechanism of a C-H activation reaction by a niobium complex. The mechanism of C-H bond activation of benzene by the TpMe2NbCH3-(c-C3H5)-(MeCCMe) complex was rationalized. The key intermediate is an unusual 2-cyclopropene complex. We rationalized the selectivities obtained for the activation of several alkylaromatics by the 2-cyclopropene niobium complex. The intriguing role of the alkyne ligand of the same complex, and its possible role in the migration processes, was investigated. In the second part of the thesis, we focused on the silicon based cross-coupling. The results suggest than the transmetalation is easier after phosphine dissociation, and in presence of the bromide ligand on the palladium. The beneficial effect of dibenzylideneacetone on the coupling was clarified.

N-phenylpyridin-2-amine , treated with stochiometric amount of palladium(II) acetate in dichloromethane at 65-70¢J for 4 h, to give high yield palladacycle 53. The reaction of palladacycle 53 with potassium aryltrifluoroborates in 1,4-dioxane at 140¢J for 24 h, could give a variety of N-(2-pyridinyl)carbazoles 55a-55m via sequential C-H bond activation. Carbazole derivative 55a reacted with irdium chloride gave iridium dimer, which followed by addition of picolinic acid via ligand exchange will form iridium complexes, which can further be utilized as OLEDs materials.

For companies, the cost of acquiring a new customer is several times the cost of retaining an existing customer. Furthermore, the purchasing power of an existing customer is usually more predominant than a new one. Therefore, more and more companies attempt to establish long-term relationships with customers in order to make them patronize again or do other useful behaviors. The concept of consumer-company identification (C-C identification) has been used to qualify the deep, meaningful, and long-term relationships between consumers and companies. This research analyzes the antecedents and consequences of C-C identification. We suggest that high identity distinctiveness and identity prestige may lead to high C-C identification. Also, high C-C identification should enhance consumers¡¦ repurchase intention and word-of-mouth (WOM). Our survey with questionnaire conducted to investigate and collect data is sent to the consumers who have shopping experience recently in department stores of Taiwan. The valid sample with questionnaire returned is 294. We analyze the results by using structural equation modeling (SEM) and find that identity distinctiveness and identity prestige have a positive relationship with C-C identification separately. Moreover, C-C identification also has a positive effect to repurchase intention and WOM. Eventually, the managerial implications of this study may help corporate managers to ponder their marketing strategies or even improve their firms¡¦ performance.

Under the conditions of transfer hydrogenation utilizing chromatographically purified ortho-cyclometallated iridium C,O-benzoate precatalysts, enantioselective carbonyl crotylation and methallylation can be performed in the absence of stoichiometric metallic reagents and stoichiometric chiral modifiers. In the case of carbonyl crotylation, use of a preformed precatalyst rather than an in situ generated catalyst results in lower reaction temperatures, providing generally higher diastereoselectivity and yields. By utilizing a more reactive leaving group in chloride over acetate on our methallyl donor, the inherently shorter lifetime of the olefin π-complex is compensated for, giving our group’s first report of reactivity utilizing 1,1-disubstituted allyl donors. / text

Los compuestos organoborados son considerados de gran interés en síntesis orgánica debido a que el enlace C-B puede ser transformado en una amplia variedad de grupos funcionales. La adicción catalítica de H-B o B-B a enlaces C-C insaturados se considera uno de los procesos catalíticos con mayor control selectivo en la formación de dichos intermedios organoborados. En el capítulo primero de la presente tesis se muestra la evolución a través de la bibliografía de las tres principales reacciones de adición catalítica de boro a alquenos, como son hidroboración, diboración y -boración. El segundo capítulo describe por primera vez la hidroboración catalítica asimétrica tanto en version homogénea como heterogeneizada de sistemas alilícos heterofuncionalizados. También describe el primer ejemplo de diboración de fenil alil sulfonas con sistemas catalíticos de Pt modificados con ligandos N-heterocíclicos. El tercer capítulo muestra la diboración catalítica de alquenos con sistemas catalíticos formados por Cu, Pd e Ir modificados con ligandos NHC. La presencia de una base y la adicción de un exceso de diborano son esenciales para obtener un alto grado de actividad y selectividad. El cuarto capítulo muestra una efectiva síntesis de boro enolatos quirales usando metales de bajo coste como son Cu y Ni modificados con ligandos NHC quirales y ligandos difosfina quirales respectivamente. El quinto capítulo describe las reacciones tándem "in situ" tales como adición de boro-acoplamiento cruzado catalizadas por complejos de Pt modificado con ligandos carbenos y Pd modificados con ligandos difosfina. / Organoboron compounds are some of the most useful reagents in organic synthesis. The carbon-boron bond, once formed, can be cleaved in a variety of ways, with or without homologation, leading to a wide range of useful functional groups. The catalytic addition of H-B or B-B across to unsaturated C-C bond is one of the catalytic processes with higher selective control in the C-B bond formation. In the first Chapter of this thesis shows the evolution through the literature of the three main catalytic reactions of boron addition to alkenes, such as hydroboration, diboration and -boration.Chapter 2 describes the first attempt at the catalytic asymmetric hydroboration in both homogeneous and heterogenised version of functionalised allylic system. In addition, the first example of the diboration reaction of these mentioned substrates with complexes based on Pt modified with NHC ligands is described.Chapter 3 discusses catalytic diboration of alkenes based on Cu, Pd and Ir- catalytic system modified with NHC ligands. The presence of a base and the use of an excess of diboron reagent are essential to obtain high degree of activity and selectivity.Chapter 4 shows the successful synthesis of chiral boron enolates by using inexpensive metals such as copper and nickel modified with chiral NHC ligands and modulated chiral commercially available diphosphines respectively. In Chapter 5 describes complexes containing transition metals such as platinum and palladium modified with NHC ligands and P,P respectively capable to perform the in situ tandem catalytic boron-addition-Suzuki-Miyaura cross-coupling.

Esta tesis doctoral se centró en la síntesis y la caracterización de nanopartículas metálicas (Pd, Ni, Pt) estabilizadas por varios tipos de ligandos y el uso de estas nanopartículas en reacciones de formación de nuevos C-C o C-heteroatomo: a) Reacción de substitución alílica catalizadas por Pd; b) Reacción de acoplamiento asimétrico de Suzuki-Miyaura; c) Reacción de acoplamiento de Suzuki-Miyaura; d) reacción de adición 1,4 de ácidos borónicos a cetonas. En cada una de estas reacciones se llevó a cabo la síntesis y caracterización de nanoparticulas metálica y complejos moleculares usando muchos tipos de ligandos en los sistemas moleculares y los sistemas análogos cataliazados por nanopartículas. Excelentes actividades y enatioselectividades fueron obtenidas en la reacción de alquilación y aminación alílica. Además, estos sistemas fueron reciclados usando líquidos iónicos. También, nuevos y selectivas nanoparticulas fueron sintetizadas y caracterizadas. Estas nanopartículas fueron usadas exitosamente en varias reacciones de formación de nuevos enlaces C-C. / This doctoral thesis focuses on the synthesis and characterization of metal nanoparticles (Pd, Ni, Pt) stabilized by several types of ligands and the used of these nanoparticles in new C-C or C-heteroatom bond formation reactions: a) Pd-catalysed asymmetric allylic substitution reactions; b) Pd-catalysed asymmetric Suzuki-Miyaura coupling reactions; c) Ni-catalysed Suzuki-Miyaura coupling reactions; d) Pt-catalysed 1,4-addition of phenylboronic acid to 2-cyclohexen-1-one reaction. For each reaction, the synthesis and characterization of metal nanoparticles and molecular complexes using several types of ligands were performed and both types of catalytic systems were tested in the appropriate reactions. Remarkably, excellent enantioselectivities using Pd/phosphite ligand were obtained in allylic substitution reaction. An efficient recovery of the catalytic system was carried out using ionic liquids as reaction medium. New active and selective nanoparticles were synthesized and characterized. These nanoparticles were applied successfully in various C-C bond formation reactions.

No description available.

ABSTRACT TRIBOLOGICAL PROPERTIES OF A TIGHTLY WOVEN CARBON/CARBON COMPOSITE Karaveli, Keriman M.Sc., Department of Metallurgical and Materials Engineering Supervisor: Prof. Dr. Abdullah &Ouml / zt&uuml / rk June 2005, 77 pages Tribological properties of a tightly woven Carbon/Carbon (C/C) composite were assessed experimentally in accord with the ASTM pin on disk technique. The C/C composite used in this study was a commercial material (K-Karb) obtained in a panel form. The composite consists of graphite fiber reinforced graphite matrix developed for aerospace applications. The fiber reinforcement was in a plain weave woven fabric form. The tests were conducted by sliding zirconia ball against the C/C composite. The friction coefficient and wear rate were determined as functions of applied load, sliding speed, sliding distance and lubrication in ambient laboratory conditions. Mean friction coefficient of the composite was 0.135 &micro / when tested at ambient atmosphere and 0.113 &micro / in lubricated environment at a load of 5 N, sliding speed of 0.5 cm/s, and sliding distance of 100 m. The wear volumes determined from surface profile traces obtained on the wear tracks after completion of the tests were used for calculations of the specific wear rates. The specific wear rates of the composite were 0.754 x 10-4 mm3/N.m at ambient atmosphere and 0.437 x 10-4 mm3/N.m in lubricated environment at the load of 5 N, sliding speed of 0.5 cm/s, and sliding distance of 100 m. The specific wear rate of the composite decreased with increasing sliding distance, sliding speed, applied load and also, decreased in lubricated environment. Keywords: C/C composite, tribology, friction, wear, lubricant.

abstract: The turmoil that China endured during the twentieth century triggered a series of social and political revolutions. As China struggled to resolve domestic questions of dynasticism or democracy and nationalism or communism, Western industrialization and imperialism dragged China rapidly into the globalizing world. Likewise, Chinese painting had to confront the West, as Chinese artists dealt with the twentieth-century version of the recurring question of modernizing Chinese painting for its times: how does one reconcile an ancient painting tradition with all the possibilities Western interactions introduced? This dissertation focuses on one artist's lifelong struggle, often overlooked, to answer this question. By examining C. C. Wang (1907-2003) and his life in art, this case study reveals broader truths about how twentieth century Chinese diaspora painters, such as Wang, modernized the tradition of Chinese ink painting. Wang's reputation as a connoisseur of ancient Chinese painting has overshadowed his own artwork, creating a dearth of research on his artistic development. Using public and private sources, this dissertation applied stylistic analysis to track this development. The analysis reveals an artist's lifelong endeavor to establish a style that would lift the Chinese painting tradition into a modern era, an endeavor inspired by modern Western art ideas and a desire to play a role in the larger movement of elevating Chinese painting. The argument is made that these efforts establish Wang as an influential twentieth century Chinese ink painter. To clarify Wang's role within the broader movement of Chinese diaspora painters, this dissertation employs a comparison study of Wang with such established twentieth century ink painting artists as Zhang Daqian, Liu Guosong, and Yu Chengyao. It is asserted that the 1949 diaspora forced this cohort of artists to adjust their style and to transcend traditional Chinese painting by integrating newly-salient ideas from Western art, particularly the abstract movement. Meanwhile, the essential Chinese identity in their art collectively became more significant. The solidarity of purpose and identity is a distinctive part of the answer this group of twentieth century Chinese diaspora painters proposed to their generation's inherited challenge of enriching the tradition. / Dissertation/Thesis / Doctoral Dissertation Art History 2014

La degradación ambiental se ha convertido en un importante problema al que deben enfrentarse la ciencia y la tecnología. Los temas tratados en este trabajo, pretenden aunar, con la introducción de los líquidos iónicos en distintos procesos, la preocupación por el medio ambiente y las inquietudes constantes del progreso. Es por esto que lo largo de esta tesis se han desarrollado nuevos sistemas catalíticos basados en líquidos iónicos, que seguidamente se han aplicado a procesos químicos de interés: - Se ha realizado un estudio de la transposición de Beckmann de oximas cíclicas para la obtención de los monómeros que posteriormente conformarán las fibras de nailon, empleando para ello líquidos iónicos como catalizadores y medios de reacción y estudiando mediante técnicas de resonancia magnética nuclear, el mecanismo que se lleva a cabo en este proceso. - Por otra parte se ha preparado y caracterizado completamente un material híbrido orgánico-inorgánico-metal, mediante el intercambio parcial de los protones de un polioxometalato con la unidad catiónica de un líquido iónico y Pd2+. Este material, como catalizador heterogeneo permite llevar a cabo la reacción de Heck de acoplamiento C-C. - Finalmente se han desarrollado organocatalizadores con características de líquido iónico, que poseen también bifuncionalidad ácido-base, con capacidad para emular la actividad de determinados sistemas enzimáticos. Estos nuevos catalizadores se han aplicado en reacciones de formación de enlaces C-C como Knoevenagel, Claisen-Schmidt, Adición de Michael y Henry. / Montón Molina, R. (2011). Hacia el desarrollo sostenible: Líquidos Iónicos como catalizadores para la transposición de Beckmann y reacciones de formación de enlaces C-C [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/10908 / Palancia