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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Direct comparison of homogeneous and heterogeneous palladium(II) catalysts for Suzuki-Miyaura cross-coupling reactions

Crawford, Katherine Alexis 30 March 2015 (has links)
The syntheses and catalytic properties of four new 1,2-acenaphthenyl N-heterocyclic carbene-supported palladium(II) catalysts are presented. The acenaphthenyl carbene can be prepared using either mesityl or 2,6-diisopropyl N-aryl substituents. In addition, two new heterogeneous analogs were synthesized with 2,6-diisopropyl N-aryl substituents that were anchored through the backbone to an insoluble silica-support. Comprehensive catalytic studies of the Suzuki coupling of aryl halides with aryl boronic acids were carried out. In general, the homogeneous diisopropyl-functionalized catalyst was found to exhibit superior selectivity and reactivity. A comparison of the performances of the aforementioned catalysts in toluene, dichloromethane and aqueous solutions are also presented. In organic solvents, the catalysts were found to be proficient for the homogeneous Suzuki coupling of aryl iodides, bromides and chlorides with boronic acids at low temperatures (35‒40 °C). Similar reactions that were carried out in aqueous media resulted in the formation of insoluble colloidal catalytic species. Nevertheless, these species still retained high activities in terms of in the Suzuki reaction with aryl chlorides. Moreover, the heterogeneous Pd precipitates can be easily recovered for subsequent use by means of filtration. The activation energies that were determined for the aryl bromide-based Suzuki reactions were found to fall in the range, 159.2‒171.2 kJ mol⁻¹ in organic solvents and 111.3‒115.9 kJ mol⁻¹ in water. The corresponding activation energy for the aryl chloride was found to be 321.8 kJ mol⁻¹ in aqueous media using the homogeneous diisopropyl-functionalized carbene catalyst. Conversely, the heterogeneous catalyst exhibited reactivity toward aryl iodides and bromides exclusively, and required significantly higher temperatures and catalyst loadings in both toluene and water. Additional experimental trials that were performed in tetrahydrofuran solution at lower temperatures resulted in substantially larger catalytic conversions. The heterogeneous catalyst allowed for easy separation and recovery. However, the catalyst exhibited a significant decrease in reactivity toward the aryl halides after two consecutive trials. / text
82

The genesis of Suzuki : an investigation of the roots of talent education

Madsen, Eric January 1990 (has links)
In its short history, Talent Education, also known as the Suzuki Method, has had a profound impact on the teaching of music to the young. However, despite continued guidance from its founder, Shinichi Suzuki, misconceptions about the method persist among both its practitioners and critics. One route to understanding of pedagogical theory is to look at its origins. To that end, this thesis makes a study of history of the method and its founder, drawing on available sources. Further investigation is carried out on the philosophy and teaching techniques. An exploration is then undertaken of the possible antecedents of Suzuki's method taking into account the prevailing ideas and practices of his cultural environment as they relate to the history, philosophy and teaching techniques of Talent Education. Findings indicate that, while Suzuki's method is clearly appropriate to contemporary society, it represents, in many of its aspects, a continuation of several beliefs and practices of traditional Japanese arts.
83

Bodily awareness the theatre writings of Michael Chekhov and Tadashi Suzuki /

Rust, Colin Michael. January 2007 (has links)
Thesis (M.A.)--Bowling Green State University, 2007. / Document formatted into pages; contains v, 88 p. Includes bibliographical references.
84

Studien zur katalytischen Aktivität von Palladium-Komplexen in Suzuki- und Sonogashira-Kreuzkupplungsreaktionen

Heiden, Markus Reinhard an der. Unknown Date (has links)
Techn. Universiẗat, Diss., 2006--Darmstadt.
85

Neue Inhibitoren zellmembranständiger Proteinkinasen

Bracht, Kathrin. January 2007 (has links)
Konstanz, Univ., Diss., 2007.
86

Synthese von neuartigen Oligoacenen und deren Anwendung in organischen Feldeffekttransistoren

Roth, Michael. Unknown Date (has links)
Techn. Universiẗat, Diss., 2006--Darmstadt.
87

Reações de acoplamento suzuki em meio homogêneo : viabilidade de reciclagem do catalisador e síntese de diarilmetanos

Nobre, Sabrina Madruga January 2004 (has links)
Este trabalho trata da reação de acoplamento Suzuki (reação entre haletos de arila ou benzila e ácidos arilborônicos) catalisada por compostos de paládio, e foi dividido em duas etapas. Na primeira etapa foi desenvolvido um sistema simples para a reação de Suzuki, em meio homogêneo, utilizando um sistema ternário de solventes (MeOH, PEO e n-heptano) (figura 1), que viabiliza o reciclo do catalisador por várias vezes. No sistema proposto foi utilizado como solvente a mistura metanol / poli( óxido de etileno), e no fmal da reação a bifenila formada foi extraída com solvente apoIar (n-heptano), com elevados rendimentos. Neste estudo, também foi possível obter produtos diferentes (rendimentos 70-80%) a cada reciclo, variando apenas o haleto de arila empregado no acoplamento. Na segunda etapa deste trabalho, foi desenvolvido um sistema para a realização do acoplamento Suzuki entre haletos de benzilas e ácidos arilborônicos catalisado por paládio. Durante o estudo de otimização foi possível verificar que estas reações ocorrem com baixa concentração de catalisador (0,002-1mol%), bem como constatou-se que o tempo de reação variou de 3h30min a 11horas, dependendo da quantidade de catalisador utilizado. O sistema se mostrou eficiente para reações com cloretos de benzila, levando a diarilmetanos com elevados rendimentos (>90%). A partir de reações competitivas se constatou que grupos substituintes no anel do haleto de benzila ou do ácido arilborônico não exercem influência estérica ou eletrônica significativa, bem como foi possível constatar que os brometos de benzilas são cinco vezes mais reativos que os cloretos de benzila. Finalmente, foi possível determinar uma reatividade relativa para os diferentes substratos halogenados frente à reação de Suzuki catalisada pelo sistema Pd(OAc)2IPPh3: (ArI > PhCH2Br > PhCH2CI > ArBr). / In this work the Pd-catalyzed Suzuki cross-coupling reaction of aryl halides or benzyl halides with aryl boronic acids was studied. In the first part of this work, we have fmd out that a system of poly (ethylene oxide) / methanol can be used as solvent medium for the Pd-catalyzed Suzuki cross-coupling reaction under mild condition. Afier the end of the reaction the product is extracted with heptane and the polar phase can be reused several without any change in the activity (Fig.1). Pure biaryl products are obtained from the no polar phase in excellent isolated yields (>90%). The same catalyst-containing polar phase was used to coupling different aryl halides, furnishing the products in good to high isolated yields (70-80%). In the second part of we have developed a simple and efficent catalytic system for the Suzuki cross-coupling reaction of benzyl halides (bromides and chlorides) with aryl boronic acids. The catalyst precursor is prepared in situ from palladium acetate and triphentylphosphine showing high activity for reaction of benzylic bromides and chlorides with arylboronic acids. The reaction can be carried out at low catalys loading (0.002 - lmol%) and under mild conditions (80°C), furnishing diarylmethane derivatives in high yelds (86-99%). Compared with the aryl halides, the Suzuki crosscoupling reaction of benzyl chlorides is much less sensitive to steric and electronic effects. On the other hand, as observed the aryl halides, the cross-coupling reaction of benzyl bromide is five times faster than the coupling of benzyl chlorides. Finally we have obtained a relative reactive for the Pd(OAchIPPh3- catalyzed Suzuki cross coupling reaction: ArI> ArCH2Br > ArCH2Cl > ArBr.
88

Reações de acoplamento suzuki em meio homogêneo : viabilidade de reciclagem do catalisador e síntese de diarilmetanos

Nobre, Sabrina Madruga January 2004 (has links)
Este trabalho trata da reação de acoplamento Suzuki (reação entre haletos de arila ou benzila e ácidos arilborônicos) catalisada por compostos de paládio, e foi dividido em duas etapas. Na primeira etapa foi desenvolvido um sistema simples para a reação de Suzuki, em meio homogêneo, utilizando um sistema ternário de solventes (MeOH, PEO e n-heptano) (figura 1), que viabiliza o reciclo do catalisador por várias vezes. No sistema proposto foi utilizado como solvente a mistura metanol / poli( óxido de etileno), e no fmal da reação a bifenila formada foi extraída com solvente apoIar (n-heptano), com elevados rendimentos. Neste estudo, também foi possível obter produtos diferentes (rendimentos 70-80%) a cada reciclo, variando apenas o haleto de arila empregado no acoplamento. Na segunda etapa deste trabalho, foi desenvolvido um sistema para a realização do acoplamento Suzuki entre haletos de benzilas e ácidos arilborônicos catalisado por paládio. Durante o estudo de otimização foi possível verificar que estas reações ocorrem com baixa concentração de catalisador (0,002-1mol%), bem como constatou-se que o tempo de reação variou de 3h30min a 11horas, dependendo da quantidade de catalisador utilizado. O sistema se mostrou eficiente para reações com cloretos de benzila, levando a diarilmetanos com elevados rendimentos (>90%). A partir de reações competitivas se constatou que grupos substituintes no anel do haleto de benzila ou do ácido arilborônico não exercem influência estérica ou eletrônica significativa, bem como foi possível constatar que os brometos de benzilas são cinco vezes mais reativos que os cloretos de benzila. Finalmente, foi possível determinar uma reatividade relativa para os diferentes substratos halogenados frente à reação de Suzuki catalisada pelo sistema Pd(OAc)2IPPh3: (ArI > PhCH2Br > PhCH2CI > ArBr). / In this work the Pd-catalyzed Suzuki cross-coupling reaction of aryl halides or benzyl halides with aryl boronic acids was studied. In the first part of this work, we have fmd out that a system of poly (ethylene oxide) / methanol can be used as solvent medium for the Pd-catalyzed Suzuki cross-coupling reaction under mild condition. Afier the end of the reaction the product is extracted with heptane and the polar phase can be reused several without any change in the activity (Fig.1). Pure biaryl products are obtained from the no polar phase in excellent isolated yields (>90%). The same catalyst-containing polar phase was used to coupling different aryl halides, furnishing the products in good to high isolated yields (70-80%). In the second part of we have developed a simple and efficent catalytic system for the Suzuki cross-coupling reaction of benzyl halides (bromides and chlorides) with aryl boronic acids. The catalyst precursor is prepared in situ from palladium acetate and triphentylphosphine showing high activity for reaction of benzylic bromides and chlorides with arylboronic acids. The reaction can be carried out at low catalys loading (0.002 - lmol%) and under mild conditions (80°C), furnishing diarylmethane derivatives in high yelds (86-99%). Compared with the aryl halides, the Suzuki crosscoupling reaction of benzyl chlorides is much less sensitive to steric and electronic effects. On the other hand, as observed the aryl halides, the cross-coupling reaction of benzyl bromide is five times faster than the coupling of benzyl chlorides. Finally we have obtained a relative reactive for the Pd(OAchIPPh3- catalyzed Suzuki cross coupling reaction: ArI> ArCH2Br > ArCH2Cl > ArBr.
89

Reações de acoplamento suzuki em meio homogêneo : viabilidade de reciclagem do catalisador e síntese de diarilmetanos

Nobre, Sabrina Madruga January 2004 (has links)
Este trabalho trata da reação de acoplamento Suzuki (reação entre haletos de arila ou benzila e ácidos arilborônicos) catalisada por compostos de paládio, e foi dividido em duas etapas. Na primeira etapa foi desenvolvido um sistema simples para a reação de Suzuki, em meio homogêneo, utilizando um sistema ternário de solventes (MeOH, PEO e n-heptano) (figura 1), que viabiliza o reciclo do catalisador por várias vezes. No sistema proposto foi utilizado como solvente a mistura metanol / poli( óxido de etileno), e no fmal da reação a bifenila formada foi extraída com solvente apoIar (n-heptano), com elevados rendimentos. Neste estudo, também foi possível obter produtos diferentes (rendimentos 70-80%) a cada reciclo, variando apenas o haleto de arila empregado no acoplamento. Na segunda etapa deste trabalho, foi desenvolvido um sistema para a realização do acoplamento Suzuki entre haletos de benzilas e ácidos arilborônicos catalisado por paládio. Durante o estudo de otimização foi possível verificar que estas reações ocorrem com baixa concentração de catalisador (0,002-1mol%), bem como constatou-se que o tempo de reação variou de 3h30min a 11horas, dependendo da quantidade de catalisador utilizado. O sistema se mostrou eficiente para reações com cloretos de benzila, levando a diarilmetanos com elevados rendimentos (>90%). A partir de reações competitivas se constatou que grupos substituintes no anel do haleto de benzila ou do ácido arilborônico não exercem influência estérica ou eletrônica significativa, bem como foi possível constatar que os brometos de benzilas são cinco vezes mais reativos que os cloretos de benzila. Finalmente, foi possível determinar uma reatividade relativa para os diferentes substratos halogenados frente à reação de Suzuki catalisada pelo sistema Pd(OAc)2IPPh3: (ArI > PhCH2Br > PhCH2CI > ArBr). / In this work the Pd-catalyzed Suzuki cross-coupling reaction of aryl halides or benzyl halides with aryl boronic acids was studied. In the first part of this work, we have fmd out that a system of poly (ethylene oxide) / methanol can be used as solvent medium for the Pd-catalyzed Suzuki cross-coupling reaction under mild condition. Afier the end of the reaction the product is extracted with heptane and the polar phase can be reused several without any change in the activity (Fig.1). Pure biaryl products are obtained from the no polar phase in excellent isolated yields (>90%). The same catalyst-containing polar phase was used to coupling different aryl halides, furnishing the products in good to high isolated yields (70-80%). In the second part of we have developed a simple and efficent catalytic system for the Suzuki cross-coupling reaction of benzyl halides (bromides and chlorides) with aryl boronic acids. The catalyst precursor is prepared in situ from palladium acetate and triphentylphosphine showing high activity for reaction of benzylic bromides and chlorides with arylboronic acids. The reaction can be carried out at low catalys loading (0.002 - lmol%) and under mild conditions (80°C), furnishing diarylmethane derivatives in high yelds (86-99%). Compared with the aryl halides, the Suzuki crosscoupling reaction of benzyl chlorides is much less sensitive to steric and electronic effects. On the other hand, as observed the aryl halides, the cross-coupling reaction of benzyl bromide is five times faster than the coupling of benzyl chlorides. Finally we have obtained a relative reactive for the Pd(OAchIPPh3- catalyzed Suzuki cross coupling reaction: ArI> ArCH2Br > ArCH2Cl > ArBr.
90

Harunobu : an Ukiyo-e artist who experimented with Western- style art

Hockley, Allen F. January 1987 (has links)
From the beginning of serious art historical study of Japanese woodblock prints or Ukiyo-e, the artist Suzuki Harunobu (1725-1770) has been accorded a prominent position in the development of that art form primarily because of his role in the creation of the first full colour prints. This, and his particular conception of feminine beauty which he chose to illustrate most often as the main subject of his art, made him the dominant artist of his generation. The popularity he achieved during his lifetime was monumental, but he met with a premature and untimely death. Shortly after his death Shiba Kōkan (1747-1818), a young artist just beginning his career, made forgeries of Harunobu's prints and later admitted to doing so in his autobiography. Based on Kōkan's confession, there developed among art historians and connoisseurs, a long running, at times heated and, as yet, unresolved debate focussed upon determining which of Harunobu's prints are in fact forgeries. Because Kōkan eventually acquired fame as an artist who experimented with styles and techniques newly imported to Japan from Europe, Harunobu's prints that contain linear perspective, one such Western technique, have traditionally and without question been designated as forgeries. To this author, making such an attribution based on this criterion seems somewhat illogical. Why would Kōkan introduce something foreign to Harunobu's style into prints he intended to pass off as Harunobu's originals? The simplest resolution to this quandary is to assume that Harunobu must have also been experimenting with imported European styles. Based on this premise, this thesis introduces literary and visual evidence linking Harunobu to a number of sources of European-style art. Much of this evidence was uncovered through a re-examination of Harunobu's prints and literary accounts of his life in accordance with the social and artistic context in which he worked. The prints and the documents which this thesis discusses have long been known to art historians. They simply needed to be reworked to support this premise. This thesis does, however, introduce one print from the collection of the Oregon Art Institute which seems to have been overlooked by other scholars. It provides a clear example of Harunobu's Western-style art and through visual analysis of it, its sources can be identified among the Western-style megane-e of Maruyama ōkyo ( 1733-1795). The concluding section of this thesis examines the consequences of this evidence. Two of the so-called forgeries are reattributed to Harunobu and his prints as a whole are recast within the tradition of Western-style art in Japan. / Arts, Faculty of / Art History, Visual Art and Theory, Department of / Graduate

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