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1	Mononuclear Ruthenium Complexes that Catalyze Water to Dioxgen Oxidation Tong, Lianpeng January 2012 (has links) The theme of this thesis is the development of mononuclear Ru-based complexes that are capable of catalyzing the water oxidation (or O2-evolving) reaction, e.g. 2 H2O → O2 + 4 H+ + 4 e−. Several families of mononuclear Ru water oxidation catalysts were designed and prepared. They feature with anionic ancillary ligands that contain carboxylate or phenolate donors. The properties of the catalysts were investigated in various aspects including coordination geometry, electrochemical behavior, and ligand exchange. All catalysts showed outstanding catalytic activity towards water oxidation in the presence of cerium(IV) ammonium nitrate as a sacrificial oxidant. High-valent Ru intermediates involved in the reactions were characterized both experimentally and theoretically. The kinetics of catalytic water oxidation was examined based on one catalyst and a prevailing catalytic pathway was proposed. The catalytic cycle involved a sequence of oxidation steps from RuII−OH2 to RuV=O species and O−O bond formation via water-nucleophilic-attack to the RuV=O intermediate. By comparing properties and catalytic performance of Ru catalysts herein with that of previously reported examples, the effect of anionic ancillary ligands was clearly elucidated in the context of catalytic water oxidation. Aiming to further application in an envisaged artificial photosynthesis device, visible light-driven water oxidation was conducted and achieved primarily in a homogeneous three-component system containing catalyst, photosensitizer, and sacrificial electron acceptor. Moreover, one model Ru catalyst was successfully immobilized on ordinary glass carbon surface through a facile and widely applicable method. / <p>QC 20121112</p> Ruthenium complex Homogeneous catalysis Water oxidation O2 evolution anionic ligand Molecular catalyst Electrocatalysis Kinetics Artificial photosynthesis Light-driven Immobilization of catalyst
2	Investigations into cyclopropanation and ethylene polymerization via salicylaldiminato copper (II) complexes Boyd, Ramon Cornell 23 January 2007 Two distinct overall research objectives are in this Masters thesis. Very little relates the two chapters apart from the ligands. The first chapter addresses diastereoselective homogeneous copper catalyzed cyclopropanation reactions. Cyclopropanation of styrene and ethyl diazoacetate (EDA) is a standard test reaction for homogeneous catalysts. Sterically bulky salicylaldimine (SAL) ligands should select for the ethyl trans-2-phenylcyclopropanecarboxylate diastereomer. Steric bulk poorly influences trans:cis ratios. Salicylaldiminine ligands do not posses the correct symmetry to affect diastereoselectivity. The SAL ligand belongs to the Cs point group in the solid state. Other ligand motifs are more effective at altering the trans:cis ratios. The second chapter addresses the general route toward successful copper(II) ethylene polymerization catalysts. Catalytic activity of the copper(II) complexes is very low. Polymer chain growth from a copper catalyst is very unlikely. Copper-carbon bonds decompose by homolytic cleavage or C-H activation. Copper-alkyls and aryls readily decompose into brown colored oils and salts with different colors. Ligand transfer to trimethylaluminum (TMA) appears to explain low yield ethylene polymerization. bulky migratory insertion mechanism coordination/insertion methodology d-block metal late transition metal phenolic ring coordination number ketimine precatalysts ketimine nitrogen bis(salicylaldiminato)copper(II) ratio cyclopropane steric bulk salicylaldiminato TMA salt trimethylaluminum aryl oil alkyl copper-aryls copper-alkyls C-H activation homolytic homolytic cleavage copper(II) polymerization ethylene cis trans symmetry diastereomer salicylaldimine SAL EDA ethyl diazoacetate styrene cyclopropanation copper diastereoselective steric protection stable CH(SiMe3)2 intermediate catalytic activity associated TMA free TMA vacant coordination site hydrolysis Lewis acid halogen anionic anionic ligand donor ligand monodentate anionic ligand aluminum(III) monodentate polymer chain polymer chain aluminum-carbon bond bulky SAL ligand open coordination site first row transition metal PE paramagnetic high molecular weight polyethylene alkylate methylaluminoxane MAO anionic ligands arylate aluminum carbon aluminum carbon bond beta-hydrogen elimination beta hydrogen elimination Aufbau reaction Aufbau neutral dialkyl aluminum aluminum-alkyl aluminum alkyl copper(0)
3	Investigations into cyclopropanation and ethylene polymerization via salicylaldiminato copper (II) complexes Boyd, Ramon Cornell 23 January 2007 (has links) Two distinct overall research objectives are in this Masters thesis. Very little relates the two chapters apart from the ligands. The first chapter addresses diastereoselective homogeneous copper catalyzed cyclopropanation reactions. Cyclopropanation of styrene and ethyl diazoacetate (EDA) is a standard test reaction for homogeneous catalysts. Sterically bulky salicylaldimine (SAL) ligands should select for the ethyl trans-2-phenylcyclopropanecarboxylate diastereomer. Steric bulk poorly influences trans:cis ratios. Salicylaldiminine ligands do not posses the correct symmetry to affect diastereoselectivity. The SAL ligand belongs to the Cs point group in the solid state. Other ligand motifs are more effective at altering the trans:cis ratios. The second chapter addresses the general route toward successful copper(II) ethylene polymerization catalysts. Catalytic activity of the copper(II) complexes is very low. Polymer chain growth from a copper catalyst is very unlikely. Copper-carbon bonds decompose by homolytic cleavage or C-H activation. Copper-alkyls and aryls readily decompose into brown colored oils and salts with different colors. Ligand transfer to trimethylaluminum (TMA) appears to explain low yield ethylene polymerization. bulky migratory insertion mechanism coordination/insertion methodology d-block metal late transition metal phenolic ring coordination number ketimine precatalysts ketimine nitrogen bis(salicylaldiminato)copper(II) ratio cyclopropane steric bulk salicylaldiminato TMA salt trimethylaluminum aryl oil alkyl copper-aryls copper-alkyls C-H activation homolytic homolytic cleavage copper(II) polymerization ethylene cis trans symmetry diastereomer salicylaldimine SAL EDA ethyl diazoacetate styrene cyclopropanation copper diastereoselective steric protection stable CH(SiMe3)2 intermediate catalytic activity associated TMA free TMA vacant coordination site hydrolysis Lewis acid halogen anionic anionic ligand donor ligand monodentate anionic ligand aluminum(III) monodentate polymer chain polymer chain aluminum-carbon bond bulky SAL ligand open coordination site first row transition metal PE paramagnetic high molecular weight polyethylene alkylate methylaluminoxane MAO anionic ligands arylate aluminum carbon aluminum carbon bond beta-hydrogen elimination beta hydrogen elimination Aufbau reaction Aufbau neutral dialkyl aluminum aluminum-alkyl aluminum alkyl copper(0)

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