Density functional theory (DFT), a powerful toolbox, can unveil chemical transformations in detail. This dissertation focuses on exploring catalytic puzzles, deciphering experimental results, and occasionally, reevaluating conventional concepts. In the first problem, a combination of DFT and kinetic studies uncovers the hidden role of borane in directed borylation reactions catalyzed by iridium complex. Borane, initially considered a side product, is revealed to be an autocatalyst. Chiral catalysts are pivotal for achieving asymmetric molecular construction. However, when the chirality center in the catalyst changes with each turnover, what impact does this have? In our second investigation, we delved into a thorough mechanistic study of enantiomeric selectivity during ruthenium complex-catalyzed hydroarylation. This study leads to a reevaluation and refinement of our concepts of asymmetric induction, specifically tailored to dynamic chirality. A series of six Ni(II) complexes featuring N-heterocyclic carbene (NHC) ligands demonstrate photocatalytic CO2 reduction to CO. Remarkably, these complexes retain their activity even in the absence of a photosensitizer, exhibiting self-sensitized photocatalytic capabilities. Our investigation involved ultrafast transient absorption spectroscopy (TAS) experiments and computational studies to provide a deeper understanding of these catalytic activities. Throughout my PhD journey at Mississippi State University, I engaged in diverse research areas within the chemistry department. The final chapter presents a series of chemistry problems encountered in the Hand Lab, where the application of DFT offers insightful solutions. These problems emerged from discussions and collaborations among graduate students, reflecting the spirit of teamwork and collective problem-solving in the department: 1. Understanding electronic structure of FAVE polymer (Smith lab); 2. Explaining the unexpected isomerization of RhCl(3-Si,Si,P) complex (Montiel lab); 3. Understanding stable dinitrogen pincer abnormal CCCPt(N2) complex (Hollis lab) and 4. Characterization of Ni tripodal PE (E = Si, Ge) complexes and studies on the hydroboration mechanism (Montiel lab)
| Identifer | oai:union.ndltd.org:MSSTATE/oai:scholarsjunction.msstate.edu:td-7346 |
| Date | 13 August 2024 |
| Creators | Le, Tri Nghia |
| Publisher | Scholars Junction |
| Source Sets | Mississippi State University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Theses and Dissertations |
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