자료유형 | 학위논문 |
---|---|
서명/저자사항 | Computational Investigations of Ruthenium-catalyzed Olefin Metathesis and Rhodium-catalyzed Olefin Hydroboration Reactions. |
개인저자 | Shao, Huiling. |
단체저자명 | University of Pittsburgh. Dietrich School Arts and Sciences. |
발행사항 | [S.l.]: University of Pittsburgh., 2019. |
발행사항 | Ann Arbor: ProQuest Dissertations & Theses, 2019. |
형태사항 | 131 p. |
기본자료 저록 | Dissertations Abstracts International 81-03B. Dissertation Abstract International |
ISBN | 9781085746298 |
학위논문주기 | Thesis (Ph.D.)--University of Pittsburgh, 2019. |
일반주기 |
Source: Dissertations Abstracts International, Volume: 81-03, Section: B.
Advisor: Liu, Peng. |
이용제한사항 | This item must not be sold to any third party vendors. |
요약 | Transition metal catalysis has proven to be a powerful strategy for olefin functionalization and polymerization reactions. Ancillary ligands play an important role in controlling the reactivity and selectivity of these catalytic reactions. Mechanistically guided rational design of ancillary ligands to achieve desired reaction outcomes has been a long-standing challenge in transition metal catalyzed olefin hydrofunctionalization and metathesis reactions because multiple properties of the ligand, including electron donating ability, steric hindrance, and ligand flexibility, could contribute simultaneously to affect the reaction mechanism, reactivity, and selectivity. To date, development of new catalytic systems has been largely dependent on trial-and-error, as well as chemical intuition. Computational investigation is emerging as an effective tool to provide molecular level understanding of reaction mechanisms, substrate effects, and ligand effects. These theoretical insights can rationalize experimental observations and facilitate ligand design. In this thesis, I present a series of computational studies to probe ligand effects in transition metal catalyzed olefin metathesis and hydroboration reactions. The specific catalytic systems investigated include effects of phosphine ligands on the initiation rate of 2nd generation Grubbs catalyst, effects of switchable N-heterocyclic carbene (NHC) ligands on reactivity of Ru-catalyzed ring-opening metathesis polymerization reactions, and effects of NHC, phosphine, and asymmetric phosphite ligands on reactivity, regio-, and stereoselectivity of Rh-catalyzed olefin hydroboration reactions.As a prerequisite to evaluate ligand effects, computational mechanistic investigations will be conducted for each catalytic reaction to identify the rate- and selectivity-determining transition states. Various computational approaches including ligand distortion energy analysis, steric and electronic ligand parameters, ligand steric contour plots, and linear free energy relationships will then be applied to gain molecular level of understanding in effects of ligands on reactivity and selectivity. The revealed dominating catalyst-substrate interactions and electronic and steric properties of ligands will provide experimental chemists with insights into design of new catalysts with improved catalytic activity, controlled selectivity, and greater substrate scope. |
일반주제명 | Chemistry. |
언어 | 영어 |
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