Sökning: "nucleophilic attack"
Visar resultat 1 - 5 av 31 avhandlingar innehållade orden nucleophilic attack.
1. (Photo)electrochemical Water Oxidation: From Catalysis to Functional Device
Sammanfattning : The key challenge within artificial photosynthesis is achieving efficient electro- or photo-driven water oxidation catalysis, a necessary process to supply the protons for the reduction reactions, thereby enabling solar fuel production. To facilitate efficient water (photo)electrolysis for solar fuel production, this thesis focuses on two aspects: 1) elucidating the O-O bond formation mechanism and developing efficient, stable, and economical water oxidation catalysts (WOCs); 2) exploring stable, low-cost, light-absorbing photoanode materials that have suitable band structures and excellent charge diffusion properties. LÄS MER
2. Direct Catalytic Nucleophilic Substitution of Non-Derivatized Alcohols
Sammanfattning : This thesis focuses on the development of methods for the activation of the hydroxyl group in non-derivatized alcohols in substitution reactions. The thesis is divided into two parts, describing three different catalytic systems. LÄS MER
3. Stereoselective Nucleophilic Additions to α-Amino Aldehydes: Application to Natural Product Synthesis
Sammanfattning : This thesis deals with the development and application of new synthetic methodology for stereo- or regioselective construction of carbon-carbon bonds in organic synthesis. The first part of this thesis describes the development of a divergent protocol for stereoselective synthesis of chiral aminodiols by employing Mukaiyama aldol additions to syn- and anti-α-amino-β-silyloxy aldehydes. LÄS MER
4. Quantum Chemical Modelling of Biomimetic Phosphoesterase Complexes
Sammanfattning : Phosphoesterases are a class of enzymes that catalyze hydrolysis of phosphoester bonds. They facilitate the modification of nucleic acid sequences, as well as the breakdown of rest products of warfare agents and insecticides. In this thesis, three biomimetic complexes that perform the same tasks are studied using density functional theory. LÄS MER
5. Potential surfaces for chemical reactions investigated by accurate quantum chemical methods
Sammanfattning : The main object of the thesis is the investigation of mechanisms for some inorganic and metallo-organic reactions by means of accurate multiconfigurational SCF and configuration interaction calculations. Stepwise dissociation of diimide into N2+H2 is found to be slightly preferred before a concerted mechanism. LÄS MER
