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Catalytic Main Group Element Bond Formation Reactions Toward the Preparation of Conjugated MaterialsMucha, Neil 01 January 2015 (has links)
Polymers incorporating main group elements offer different and interesting properties compared to their all carbon analogues. For example, π-conjugated polymers incorporating phosphorus in the main chain of the polymer have generated interest due to their unique thermal and electronic properties, which primarily result from delocalization of the phosphorous lone pair within aromatic units. Similarly, interest in polysilanes stems from conductivity resulting from σ electron delocalization, though current methods of preparation for both of these types of materials are lacking. In this dissertation, both early and late transition-metal compounds were used to dehydrocouple phosphine and silane substrates. The use of dehydrocoupling catalysis as a method for the synthesis of main group element-linked polymers was explored utilizing substrates designed to engender solubility in their polymeric products. Progress towards the preparation of silane- and phosphine-based conjugated materials via dehydrocoupling catalysis is reported.
Catalytic reactions of bisphosphinite pincer-ligated iridium compounds p-XR(POCOP)IrHCl (POCOP) = 2,6-(R2PO)2C6H3, R = iPr, tBu, X = H, COOMe, H, NMe2with primary and secondary silanes have been performed. Compounds featuring the less sterically demanding iPr-substituted ligands facilitate silane redistribution reactions, but dehydrocoupling catalysis is observed for more encumbered silane substrates or with aggressive removal of H2. The bulkier tBu-substituted compounds are silane dehydrocoupling precatalysts that also undergo competitive redistribution with less hindered substrates. Products generated from reactions utilizing tBu ligated Ir include low molecular weight oligosilanes with varying degrees of redistribution present or disilanes when employing more sterically demanding substrates. The interplay of steric and electronic effects of the POCOP ligand on the silane product distribution will be presented.
In previous work by our group, a triamidoamine-supported zirconium catalyst,[κ5-(Me3SiNCH2CH2)2NCH2CH2NSiMe2CH2]Zr, 1 has been shown to be effective in catalyzing the formation of phosphorus–element bonds via dehydrocoupling. Substrates including 2,5-bisphosphinofuran and 1,4-bisphosphinobenzene were dehydrocoupled to yield hyperbranched polyphosphine products. Efforts to characterize these products have been limited due to poor solubility. Rational substrate design incorporating aliphatic sidechains in primary phosphine linker molecules to engender solubility has been accomplished. Treatment of these second generation substrates with 1 or [Cp*2ZrH3]Li, 2 leads to sluggish reactions reaching moderate conversions to diphosphine products. The working hypothesis is that steric congestion during the bond forming step hinders additional bond-formation. Efforts toward the characterization and utilization of these insoluble materials as metal ion scavengers will be presented.
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Chimie de coordination du phosphore aux métaux du groupe 11 : progrès en catalyse de couplage C-N au Cu(I) et nouveaux complexes polyphosphines de l'Au(I) / Phosphorous coordination chemistry to group 11 metals : improvements in C-N cross-coupling catalyzed by Cu(I) and new polyphosphinic complexes of Au(I)Rampazzi, Vincent 23 June 2014 (has links)
De nos jours et depuis quelques années maintenant, le principe de développement durable encourage les chimistes de tous horizons à développer de nouvelles méthodes de synthèse économiques et écologiques, les ressources naturelles de notre planète ne sont pas illimitées. Parmi les ressources les plus exploitées, nous trouvons le pétrole et le gaz. Outre ces derniers et le gaz, les métaux précieux sont également devenus indispensables.Cette thèse se concentre sur la valorisation de complexes de cuivre et d’or, obtenus à partir de ligands phosphorés synthétisés au sein du laboratoire. Dans un premier temps, nous verrons la mise au point d’une réaction de N-arylation de pyrazoles catalysée par un complexe de cuivre portant un ligand hybride phosphinoalcène. Dans un deuxième temps, les propriétés de coordination de l’or à différentes polyphosphines ferrocéniques seront étudiées. Plusieurs complexes innovants seront mis en évidence et pourront être utilisés dans le cadre de futures études de catalyse, ou de luminescence. / Nowadays, sustainable development encourages chemists to develop new economic and ecologic synthesis, because natural ressources are reducing. Most exploited ressources are gas and petroleum, but precious metals are also essential. This thesis is focusing on the enhancement of gold and copper complexes, obtained in our laboratory from phosphorous-based ligands. In the first part, we will develop a new system for the N-arylation of pyrazoles from a copper complexe coordinated by a new hybrid phosphinoalkene ligand. In the second part, coordination properties of gold to different ferrocenic polyphosphine will be studied. Several new innovative complexes will be isolated, and could be used in future catalytic or luminescent studies.
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