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21	<b>Substrate-Directed Heterogeneous Hydrogenation of Olefins Using Bimetallic Nanoparticles</b> William Alexander Swann (19172248) 18 July 2024 (has links) <p dir="ltr">Directed hydrogenation, in which product geometric selectivity is dictated by the binding of an ancillary directing group on the substrate to the catalyst, is typically achieved by homogeneous Rh and Ir complexes. No heterogeneous catalyst has been able to achieve equivalently high directivity due to a lack of control over substrate binding orientation at the catalyst surface. In this work, we demonstrate through structure-activity studies that careful control of surface ensemble geometry in bimetallic nanoparticle catalysts can confer hydroxyl-directed selectivity in heterogeneous double bond hydrogenation. We postulate that the oxophilic alloy component binds hydroxyl groups to pre-orient the molecule on the surface, while proximal noble metal atoms impart facially selective addition of hydride to the olefin. We found that controlling the degree of surface alloying between oxophilic and noble metal component as well as alloy component identity is critical to maximizing reaction selectivity and starting material conversion. Our optimized catalysts exhibit good functional group tolerance on a variety of cyclohexenol and cyclopentenol scaffolds, with Pd-Cu and Pt-Ni systems being developed for the diastereoselective hydrogenation of tri- and more challenging tetra-substituted olefins, respectively. The applicability of this method is then demonstrated in a four-step synthesis of a fine fragrance compound, (1<i>R</i>,2<i>S</i>)-(+)-<i>cis</i>-methyldihydrojasmonate (Paradisone®), with high yield and enantiopurity.</p> Solid state chemistry Transition metal chemistry Nanochemistry Structure and dynamics of materials Organic chemical synthesis Catalysis and mechanisms of reactions Colloid and surface chemistry Directed Hydrogenation Substrate Direction Bimetallic Nanoparticle Catalysis Alloy Ensemble Geometry Stereochemistry
22	SURFACE CHEMISTRY CONTROL OF 2D NANOMATERIAL MORPHOLOGIES, OPTOELECRONIC RESPONSES, AND PHYSICOCHEMICAL PROPERTIES Jacob Thomas Lee (12431955) 12 July 2022 (has links) <p>This dissertation describes how the surface chemistries of 2D nanomaterials can be modified to alter overall material properties. Specifically, through a focus of the ligand-surface atom bonding in addition to the overall ligand structure we highlight the ability to direct morphological outcomes in lead free halide perovskites, maximize optoelectronic responses in substoichiometric tungsten oxide, and alter physicochemical properties titanium carbide MXenes. </p> Transition metal chemistry Macromolecular materials Nanochemistry Optical properties of materials Physical properties of materials Structure and dynamics of materials Supramolecular chemistry Colloid and surface chemistry Localized Surface Plasmon Resonance MXenes WO3-x 2D nanomaterials perovskite lead-free perovskite surface chemistry covalent attachment 2D morphology optoelectronic characteristics Inorganic Chemistry Optical Properties of Materials Physical Chemistry of Materials Synthesis of Materials Transition Metal Chemistry Chemical Characterisation of Materials Colloid and Surface Chemistry

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<b>Substrate-Directed Heterogeneous Hydrogenation of Olefins Using Bimetallic Nanoparticles</b>

SURFACE CHEMISTRY CONTROL OF 2D NANOMATERIAL MORPHOLOGIES, OPTOELECRONIC RESPONSES, AND PHYSICOCHEMICAL PROPERTIES